EP0699883A2 - Refrigerating system - Google Patents
Refrigerating system Download PDFInfo
- Publication number
- EP0699883A2 EP0699883A2 EP95113686A EP95113686A EP0699883A2 EP 0699883 A2 EP0699883 A2 EP 0699883A2 EP 95113686 A EP95113686 A EP 95113686A EP 95113686 A EP95113686 A EP 95113686A EP 0699883 A2 EP0699883 A2 EP 0699883A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- refrigerant
- cool storage
- evaporator
- temperature
- refrigerating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B5/00—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity
- F25B5/04—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity arranged in series
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/31—Expansion valves
- F25B41/33—Expansion valves with the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant
- F25B41/335—Expansion valves with the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant via diaphragms
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/39—Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
- F25D16/00—Devices using a combination of a cooling mode associated with refrigerating machinery with a cooling mode not associated with refrigerating machinery
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/24—Storage receiver heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2500/00—Problems to be solved
- F25B2500/05—Cost reduction
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2500/00—Problems to be solved
- F25B2500/15—Hunting, i.e. oscillation of controlled refrigeration variables reaching undesirable values
Definitions
- the present invention relates to a refrigerating system and more particularly to a refrigerating system for a refrigerating compartment for a refrigerated vehicle, which system includes an evaporator for a cool storage area and an evaporator for a refrigeration area.
- a refrigerating system for a refrigerated vehicle with a cool storage capability as disclosed in Japanese Unexamined Patent Publication No. 64-6654, which apparatus includes a refrigerating device for executing a refrigerating cycle, an outer blower and an inner blower.
- the refrigerating unit includes a compressor, a condenser, temperature responsive automated expansion valves, an evaporator for a refrigeration area, an evaporator for a cool storage area, and a gas-liquid separator or accumulator.
- the first temperature responsive automated valve has a diaphragm opened to a temperature sensitive tube at an outlet of the refrigerating evaporator via a capillary conduit, so that the size of an orifice, i.e., the pressure amount of the refrigerant introduced into the gas/liquid separator, is controlled in accordance with the temperature of the refrigerant at the outlet of the evaporator.
- the second temperature responsive automated valve has, also, a diaphragm opened to a temperature sensitive tube at an outlet of the cool evaporator via a capillary conduit, so that the size of an orifice, i.e., the pressure amount of the refrigerant introduced into the gas/liquid separator, is controlled in accordance with the temperature of the refrigerant at the outlet of the cool storage evaporator.
- the refrigerating evaporator and the cool storage evaporator are arranged in parallel.
- the prior art refrigerating system is further provided with switching valves, which are repeatedly and intermittently operated between open and closed conditions, so as to obtain a refrigerating operation and a cool storage operation.
- the cool storage material in the cool storage evaporator melts, which is effective for maintaining a desired low temperature inside the refrigerating compartment.
- the repeated opening or closing operation of the switching valves in the prior art allows the refrigerating operation and the cool storage operation to be effectively executed.
- the parallel arrangement of the refrigerating evaporator and the cool storage evaporator necessitates two thermo-sensitive automated operation valves as well as two switching valves, which causes the number of the parts to be increased, thereby increasing the production cost.
- melting of the cool storage material is commenced from its outer portion, which can easily contact the air in the refrigerating compartment. In other words, melting of the cool storage material located at the inner side adjacent to the tube of the cool storage evaporator is less likely. As a result, effective use of the latent heat of fusion of the cool storage material cannot be obtained.
- An object of the present invention is to provide a refrigerating system of a reduced cost capable of obtaining a refrigerating operation as well as a cool storage operation, which are effective.
- Another object of the present invention is to provide a refrigerating system capable of preventing the cool storage material from being melted during a de-frosting operation.
- Still another object of the present invention is to provide a refrigerating system capable of obtaining an effective refrigerating operation while obtaining an increased performance during a cool-down operation.
- Another object of the present invention is to provide a refrigerating system capable of preventing a cool keeping operation from being affected by increasing the heat absorbing performance of the refrigerant at the cool storage evaporator.
- Still further object of the present invention is to provide a refrigerating system capable of obtaining an increased cooling performance at an initial phase after a cool storage operation.
- a refrigerating system which comprises: a heat insulated chamber; means for generating a flow of air recirculated in the chamber; means arranged in the chamber for holding an amount of cool storage material; a compressor for compression of a refrigerant; a condenser for receiving the compressed refrigerant from the compressor; an expansion valve for reducing the pressure of the refrigerant from the condenser; a first evaporator for receiving the refrigerant of the reduced pressure for cooling the cool storage material; a second evaporator for receiving the refrigerant of the reduced pressure for cooling the air flow recirculated in the chamber; a closed passageway for the refrigerant being constructed by the compressor, the condenser, the temperature sensitive expansion valve, the first evaporator and the second evaporator; said expansion valve being of a type capable of controlling the amount of the recirculated refrigerant in accordance with the temperature of the refrigerant at an outlet side of the second e
- the refrigerating system further comprises, in addition to the closed passageway, an additional passageway for connecting the recirculating passageway at a location between the compressor and the condenser with the recirculating passageway at a location between the first and second evaporators, and a switching means for obtaining switching between a first condition where the flow of the refrigerant along the closed passageway, i.e., the refrigerant from the compressor is passed through the condenser, the expansion valve and the first evaporator and is introduced into the second evaporator, and a second condition where the refrigerant from the compressor is passed through the additional passageway and is introduced into the second evaporator, i.e., by-passing the cool storage evaporator.
- the by-passing of the cool storage evaporator during the second condition can obtain a de-frosting operation, while preventing the cool storage material in the cool storage evaporator from melting.
- said temperature sensitive expansion valve comprises a first variable orifice in the recirculating passageway, a second variable orifice located downstream from the first orifice, and an actuator responsive to the temperature of the refrigerant at the outlet of the evaporators for controlling the first and second orifices in such a manner that, during the cool storage operation, an adiabatic expansion of the refrigerant occurs at the first orifice, while, during the refrigerating operation, an adiabatic expansion of the refrigerant occurs at the second orifice.
- the refrigerating operation a large amount of the recirculated refrigerant, suitable for the high load operation, is obtained, thereby maintaining a desired performance during a cool-down operation.
- the second orifice can operate within a range where the degree of the superheating is controlled, thereby preventing hunting from occurring.
- the refrigerating system further comprises sensor means for detecting the temperature inside the chamber, and means for controlling the air flow generating means in such a manner that an increased amount of the air flow is obtained when the temperature inside the chamber is higher than a predetermined value during the refrigerating operation.
- sensor means for detecting the temperature inside the chamber and means for controlling the air flow generating means in such a manner that an increased amount of the air flow is obtained when the temperature inside the chamber is higher than a predetermined value during the refrigerating operation.
- an increase in the cooling capacity is obtained at the initial stage of the cool storage or refrigerating operation due to the fact the cool storage material is melted.
- an increase in the evaporating temperature at the refrigerating evaporator cause the melting of the cool storage material to be commenced at a region adjacent the cool storage evaporator.
- an effective use of the latent heat of melting of the cool storage material is realized.
- a refrigerating system comprising: a heat insulated chamber; means for generating a flow of air recirculated in the chamber; means arranged in the chamber for holding an amount of cool storage material, and; a refrigerating recirculating unit including a compressor for compression of a refrigerant, a condenser for receiving the compressed refrigerant from the compressor, an expansion valve for reducing the pressure of the refrigerant from the condenser, a first evaporator for receiving the refrigerant at the reduced pressure for cooling the cool storage material, and a second evaporator for receiving the refrigerant of the reduced pressure for cooling the air flow recirculated in the chamber, a closed passageway for the refrigerant being constructed by the compressor, the condenser, the temperature sensitive expansion valve, the first evaporator and the second evaporator, said expansion valve being of a type capable of controlling the amount of the recirculated refrigerant in accordance with the temperature
- said serpentine tube include portions projected out of and located below said packs.
- the projected portion functions as a heat pipe, thereby improving the cooling of the air inside the chamber.
- FIG. 1 shows a construction of a refrigerating system for a refrigerated vehicle
- Fig. 2 shows the refrigerated vehicle to which the refrigerating system in Fig. 1 is attached.
- the refrigerated vehicle 2 is provided with a refrigerating system 1.
- Fig. 1 shows a construction of a refrigerating system for a refrigerated vehicle
- Fig. 2 shows the refrigerated vehicle to which the refrigerating system in Fig. 1 is attached.
- the refrigerated vehicle 2 is provided with a refrigerating system 1.
- Fig. 1 shows a construction of a refrigerating system for a refrigerated vehicle
- Fig. 2 shows the refrigerated vehicle to which the refrigerating system in Fig. 1 is attached.
- the refrigerated vehicle 2 is provided with a refrigerating system 1.
- Fig. 1 shows a construction of a refrigerating system for a refrigerated vehicle
- Fig. 2
- the refrigerating system 1 includes a refrigerating compartment 3, a refrigerating unit 4 with a cool storage device for cooling the refrigerating compartment 3, an inside blower 6 located inside the refrigerating compartment 3, and outside blower 7 located outside the refrigerating compartment 3, and a control panel 8 in which control circuitry is housed for controlling the energization of the various parts of the system 1.
- the refrigerating compartment 3 is formed with a thermally insulated construction. Namely, the refrigerating compartment 3 is connected to a body of the refrigerated vehicle 2, and is formed as a box of a rectangular parallelepiped shape formed from a heat insulating material having a chamber therein for storing frozen or refrigerated foods. In a well known manner, the refrigerating compartment 3 is provided with a door 2-1 at the rear side thereof.
- the refrigerating unit 4 for executing the refrigerating cycle includes a refrigerant compressor 11, a refrigerant condenser 12, a receiver 12a, a temperature operated automatic valve 13, a cool storage evaporator 14, a refrigerating evaporator 15, an accumulator 16 and a refrigerant flow switching valve 17. Furthermore, pipes are provided for connecting theses components with each other so that a refrigerating cycle is executed.
- the compressor 11 has an outlet 11-1 connected to an inlet 12-1 of the condenser 12.
- the condenser 12 has an outlet 12-2 connected to the receiver 12a.
- the receiver 12a is connected, via the temperature operated automatic valve 13, to an inlet 26 of the cool storage evaporator 14.
- the cool storage evaporator 14 has an outlet 27 connected to an inlet 15-1 of the refrigerating evaporator 15.
- the refrigerating evaporator 15 has an outlet 15-2 connected, via the accumulator 16, to an inlet 11-2 of the compressor 11.
- a reference numeral 20 denotes an internal combustion engine of the refrigerated vehicle 2, and has a crankshaft 20-1, on which a pulley 20-2 is connected.
- the compressor 11 has a rotating shaft 11-3 and a pulley 11-4 on the shaft 11-3.
- a belt 19 is provided for obtaining a kinematic connection between the pulleys 20-2 and 11-4.
- the pulley 11-4 is connected to a clutch 18 for selective transmission of a rotating movement of the pulley 11-4 to the compressor 11. As a result, an engagement of the clutch 18 causes the compressor 11 to be operated for executing a compression operation.
- the gaseous refrigerant sucked from the inlet 11-2 is subjected to a compression, and the compressed gas at a higher temperature and pressure is discharged from the outlet 11-1.
- an electrically operated compressor the rotational speed of which is controlled by an inverter, can be employed.
- the compressor may be of a type of a variable outlet amount.
- the refrigerant condenser 12 is arranged at a desired location of the refrigerated vehicle 2, where an outside air flow, generated by the movement of the vehicle, is effectively contacted, i.e., at a bottom location of the refrigerating compartment 3 as shown in Fig. 2.
- the gaseous refrigerant of high temperature and pressure from the compressor 11 is subjected to a heat exchange with the outside air flow generated by the outside blower 7 and the air flow generated by the movement of the refrigerated vehicle 2.
- the gaseous refrigerant is liquidized and is introduced into the receiver 12a, where the liquid state refrigerant is separated.
- the receiver 12a can be eliminated in case where a complete liquidation occurs at the condenser 11.
- the temperature-sensitive automated valve 13 as an expansion valve is constructed by a valve member 21 as a throttle valve and a temperature sensing unit 22 for operating the valve member 21.
- the valve member 21 forms a throttled orifice (not shown) for ejecting the refrigerant from the condenser 12, so that the refrigerant is subjected to an expansion, thereby obtaining a gas-liquid combined state of the refrigerant at a low temperature and pressure.
- the temperature sensitive unit 22 includes, in a well known manner, a temperature sensitive tube 23, a operating member 24-1 such as a diaphragm actuator, and a capillary tube 24 having a first end opened to the space inside the temperature sensitive tube 23 and a second end opened to the diaphragm 24-1.
- a gas having the same components as the refrigerant is sealingly stored, so that the pressure of the gas in the temperature sensitive tube 23 corresponds to a degree of a superheat of the gaseous refrigerant sucked into the compressor, which corresponds to the change in the temperature of the refrigerant at the outlet of the refrigerating evaporator 15.
- the term "superheat” means an increase in a temperature (enthalpy) after a equibrium state is established during an evaporating phase in a refrigerating cycle.
- the pressure in the temperature sensitive tube 23 is opened to the diaphragm 24-1, so that the valve 21 controls the degree of the throttle in accordance with the pressure change.
- an increase in the temperature of the refrigerant at the outlet of the refrigerating evaporator 15 causes the gas in the pressure sensitive tube to expand, so that the operating unit 24-1 causes the valve 21 to be moved in a direction to increase a flow area thereby increasing the amount of the recirculated refrigerant, which causes the temperature of the refrigerant to be decreased.
- a decrease in the temperature of the refrigerant at the outlet of the refrigerating evaporator 15 causes the gas in the pressure sensitive tube to be compressed, so that the operating unit 24-1 causes the valve 21 to be moved in a direction to decrease a flow area, thereby reducing the amount of the recirculated refrigerant, which causes the temperature of the refrigerant to be increased.
- Fig. 3 illustrates a construction of the cool storage evaporator 14, which is located in the refrigerating compartment 3 at its top portion as shown in Fig. 2.
- the cool storage evaporator 14 is, in the refrigerating circuit, located at a position upstream from the refrigerating evaporator 15.
- a heat exchange occurs between the gaseous-liquid combined state refrigerant and the cool storage material, so that the cool storage material is cooled, on one hand, and the refrigerant is evaporated to a gaseous state, on the other hand.
- the cool storage evaporator 14 is, as shown in Fig.
- the tube 25 is formed as a serpentine shape which is constructed by a straight portions 25-1 spaced in parallel and curved portions 25-2 connecting the straight portions 25-1 with each other. Laterally two adjacent vertical rows of pairs of packs 5 are provided. In each pair, two adjacent straight portions are arranged between the packs 5.
- the refrigerant from the condenser 12 is passed through the tube 25, so as to cool the cool storage material.
- a flattened refrigerant tube can be employed for increasing a heat exchanging surface area for increasing the refrigerating capacity.
- fins can be provided for increasing the heat exchanging capacity.
- a cool storage material is stored, such as a brine (a water solution of calcium chloride or sodium chloride et al.), or methanol water brine.
- a cool storage material is used, which has a soldifing temperature or a melting temperature of, for example, -25°C, which is similar to the evaporating temperature of the refrigerant of, for example, -25°C of the refrigerating evaporator 15, when the temperature of the refrigerating compartment 2 is reached to a first predetermined temperature of, for example, -20°C.
- the cool storage material When the refrigerating system 4 is out of operation, i.e., the clutch 18 in the pulley 11-4 is de-energized for disconnecting the compressor 11 from the rotating movement of the engine crankshaft 20-1, the cool storage material is melted, thereby maintaining a low temperature of the chamber inside the refrigerating compartment 3. In other words, latent heat, which is adsorbed when the cool storage material is melted, deprives heat from the refrigerating compartment 3, thereby maintaining a cooled condition of the refrigerating compartment.
- the soldifing or melting temperature of the cool storage material is -25°C. However, an adjustment of the soldifing or melting temperature of the cool storage material is possible by varying the amount of the solute such as salt in a solvent such as a water of a fixed amount, or a set temperature at the refrigerating compartment 3.
- the refrigerating evaporator 15 is arranged in a duct of a cooling unit 28 arranged at a top side of the refrigerating compartment 3, and is, in a well known manner, constructed as a stacked type heat exchanging device which is constructed by a pair of spaced tanks, a stack of heat exchanging tubes extending between the tanks and fins on the outer surfaces of the heat exchanging tubes.
- a heat exchange occurs between an inflow of refrigerant from the cool storage evaporator and a flow of an inner air generated by the inner blower 6, so that the refrigerant is evaporated.
- the accumulator 16 is for separating the refrigerant from the refrigerating evaporator 15 into a liquid phase and a gaseous phase, and for discharging only the gaseous phase refrigerant into the compressor 11.
- the flow switching valve 17 as an electromagnetic valve is arranged on a hot by-pass passageway 30 having one end connected to a recirculating pipe between the outlet 11-1 of the compressor 11 and the inlet 12-1 of the condenser 12.
- the flow switching valve 17 is switched between a closed position where a normal flow of the refrigerant is obtained via the condenser 12, the receiver 12a, a recirculation pipe 29, the cool storage evaporator 14 and a check valve 29a, and an opened position where a by-passed flow of the refrigerant is obtained via the by-pass passageway 30.
- the passageway 29 allows the refrigerant to pass through the condenser 12, the receiver 12a as shown by an arrow a , the expansion valve 13, and the cool storage evaporator 14.
- the passageway 30 allows the refrigerant to be directly introduce into the refrigerating evaporator 15, as shown by an arrow b , i.e. to by-pass the condenser 12, the receiver 12a, the expansion valve 13, and the cool storage evaporator 14, thereby executing a defrosting operation.
- the check valve 29a prevents the refrigerant from being reversed.
- the inner blower 6 is constructed by a inner fan 31 for generating an air flow in the duct of the cooling unit 28 and an electric motor 32 for generating a rotating movement applied to the inner fan 31.
- a bearing means is provided for rotatably connecting the fan 31 to the duct of the cooling unit 28.
- the fan 31 when the rotating movement from the electric motor 32 is applied, sucks the inner air in the refrigerating compartment 3 into the duct of the cooling unit 28 as shown by an arrow f1, so that the air flow is directed to the refrigerating evaporator 15 arranged in the duct.
- a heat exchange is occurred at the evaporator 15 between the refrigerant and the air flow, which causes the air flow is cooled.
- a control panel 8 is arranged inside the refrigerating compartment 3 for controlling the operation of the inner fan motor 32.
- the electric motor 32 can be provided with a means for obtaining two or more steps of control, or a stepless control, of the motor 32.
- the outside blower 7 is, as shown in Fig. 1, constructed by an outer fan 33 for generating an outside air flow contacting with the refrigerant condenser 12 and an outer fan motor 34 for generating a rotating movement applied to the outer fan 33.
- the outer fan 33 is located adjacent to the condenser 12.
- the outer fan motor 34 is also controlled by the control panel 8, so that the fan motor 34 is selectively operated. It is also possible to construct the control panel 8 such that two or more steps of control, or a stepless control, of the motor 32 is obtained in order to adjust the amount of the air flow generated by the outside fan 33.
- Fig. 4 shows, schematically, a construction of the control panel which is constructed as a microcomputer system including, in a well known manner, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM) and a timer circuit (clock signal generator).
- various switches, setters and sensors are connected to the control panel 8, such as a switch 8-1 for making the refrigerating system operate, a switch 8-2 for obtaining a desired setting of a temperature inside the refrigerating compartment 3, a de-frosting switch 8-3, a sensor 37 for detecting an actual temperature inside the refrigerating compartment 3, and a sensor for detecting a temperature of the cool storage material.
- Relay coils 39 to 42 are also connected to the control panel 8.
- the relay coil 39 has a contact 43 for controlling an on-off operation of the clutch 18.
- the relay coil 40 has a contact 44 for controlling an on-off operation of the refrigerant flow switching valve 17.
- the relay coil 41 has a contact 45 for controlling an on-off operation of the inner fan motor 32.
- the relay coil 42 has a contact 46 for controlling an on-off operation of the outer fan motor 34.
- the control panel 8 responds to signals from the operating switch 8-1, the inner temperature set switch 8-2, the de-frosting switch 8-3, the inner temperature sensor 37 and the cool storage material temperature censor 38 so that the relay coils 39 to 42 are selectively energized in such a manner that a desired manner of operations of the clutch 18, the refrigerant flow switching valve 17, the inner fan motor 32 and the outer fan motor 34 is obtained, as will be fully described later.
- the operation switch 8-1 commences a refrigerating operation as well as a cool storage operation of the refrigerating system 4.
- the operating switch 8-1 is made ON, a signal is issued to obtain the refrigerating operation and the cool storage operation, which are alternately executed.
- the set switch 8-2 can set a temperature inside the refrigerating compartment to a desired temperature of, for example, -18°C.
- the defrost switch 8-3 initiates a defrosting operation, where the refrigerant flow direction switching valve 17 is made ON for a predetermined duration of time, such as one hour, thereby defrosting the refrigerating evaporator 15.
- the inner temperature sensor 37 is constructed as a thermistor or thermostat and is arranged at a suitable location inside the refrigerating compartment 3 to detect the inside temperature.
- the control panel 8 is programmed such that, when the temperature Ta inside the refrigerating compartment 3, as detected by the sensor 37, is reduced to a value which is lower than a first predetermined value T1, which corresponds to the set temperature Ts minus a predetermined temperature reduction ⁇ T (°C) and is, for example, a value of -20°C, the inside fan motor 32 is made OFF, which allows a cool storage operation to be commenced.
- a second predetermined value T2 which corresponds to the set temperature Ts plus a predetermined temperature increase ⁇ T (°C) and is of, for example, a value of -16°C
- ⁇ T a predetermined temperature increase
- the cool storage material temperature sensor 38 is constructed, for example, as a thermistor or thermostat, and is arranged on a surface of the cool storage pack 5 such that the temperature Tb of the cool storage material is detected by the sensor 38.
- the control panel 8 is programmed such that, when the temperature Tb of the cool storage material detected by the sensor 38 is reduced to a temperature lower than a setting temperature Tg of the cool storage material, i.e., when temperature Tb is reduced to the setting temperature Tg minus a predetermined value ⁇ T (°C) (for example 25°C - 2°C), the clutch 18 of the refrigerant compressor 11, the inside fan motor 32 and the outside fan motor 34 are made OFF, thereby executing the cool keeping operation.
- ⁇ T for example 25°C - 2°C
- the relay coils 39 to 42 selectively make on or off the relay switches 43 to 46 for selectively energizing the clutch 18 of the refrigerant compressor 11, the inside fan motor 32 and the outside fan motor 34, respectively.
- a semi-conductor switching circuit using semi-conductors can be employed.
- the refrigerating system can take various modes of operation, including the cooling mode, the cool storage mode, the de-frosting mode, and the OFF mode (cool keeping mode) as selected by the control panel 8.
- Table 1 shows, at these various modes, operating conditions of the refrigerant switching valve 17, the electromagnetic clutch 18, the inside fan motor 32 and the outside fan motor 34.
- Fig. 5 is a flowchart illustrating a operation of the control panel 8 for switching between the refrigerating operation and the cool storage operation.
- a solidifying temperature Tg of the cool storage material minus a predetermined reduced value ⁇ T (°C) is calculated.
- a set temperature Ts set by the inside temperature set switch 8-2 is read out.
- the inner chamber temperature Ta detected by the inner temperature sensor 37 and the cool storage material temperature Tb detected by the sensor 38 are read out.
- step S5 it is determined if the inside temperature Ta detected by the inside temperature sensor 37 is lower than the first predetermined temperature T1 of, for example, -20°C.
- the routine goes to step S6, where it is determined if the inside temperature Ta detected by the inside temperature sensor 37 is higher than the second predetermined temperature T2 of, for example, -16°C.
- step S6 When a result of the determination at the step S6 is "Yes", i.e., the inside temperature Ta is higher than the second predetermined temperature T2, the routine goes to step S7, where the refrigerating operation is executed by making ON the clutch 18 of the refrigerant compressor 11, and the inside and outside fan motors 32 and 34 and by making OFF the refrigerant flow switching valve 17. The routine goes to step S2 for a repetition.
- step S5 When a result of a determination is "Yes” at the step S5, i.e., the inside temperature Ta is lower than the first predetermined temperature T1 (Ta ⁇ -20°C), or a result of a determination is "No” at the step S6, i.e., the inside temperature Ta is lower than the second predetermined temperature T2 and higher than the first predetermined value (-20°C ⁇ Ta ⁇ -16°C), the routine goes to step S8, where it is determined if the temperature of the cool storage material Tb detected by the sensor 38 is lower that the setting temperature Tg (-25°C) minus ⁇ T (-2°C).
- step S8 When a result of "No" is obtained at the step S8 (Tb > -27°C), the routine goes to step S9, where the cool storage operation executed by making ON the clutch 18 of the refrigerant compressor 11 and the outside fan motor 34 and by making OFF the refrigerant flow switching valve 17 and the inside fan motor 32. The routine goes to step S2 for a repetition.
- step S8 When a result of a determination is "Yes” at the step S8 (Tb ⁇ -27°C), the routine goes to step S10, where the cool keeping operation executed by making OFF the clutch 18 of the refrigerant compressor 11, the inside and outside fan motors 32 and 34, and the refrigerant flow switching valve 17. It should be noted that the "No" determination at step S6 (-20°C ⁇ Ta ⁇ -16°C) can cause the routine goes to step S9 without executing the step S8.
- Figs. 6A to 6E illustrate timing charts illustrating an inside temperature, an evaporating temperature, an operating condition of the inside fan, an operating mode of the apparatus and an operating condition of the electromagnetic clutch, respectively.
- the operating switch is made ON, which causes the compressor 11, the inside fan 31 and the outside fan 33 to be brought into operation.
- the refrigerant flow direction switching valve 17 is maintained in its OFF condition, so that a flow of the refrigerant by way of the first refrigerating passageway 29 is obtained.
- the gaseous state refrigerant of a high temperature and pressure from the compressor 11 is introduced into the condenser 12, where the refrigerant is liquidized, and into the receiver 12a where separation occurs between the gaseous and liquid phases. Only the liquid state refrigerant is introduced into temperature operated automatic valve 13, where the liquid state refrigerant is subjected to a rapid expansion, so that the refrigerant is changed to a mist state (gas and liquid combined state) at a low temperature and pressure.
- the mist state refrigerant is introduced into the circular tube 25 of the cool storage evaporator 14, so that a heat exchange occurs between the refrigerant and the cool storage material in the cool storage packs 5, so that the refrigerant is evaporated, so as to obtain a gas and liquid combined state, where the amount of the gaseous component is larger than the amount of the liquid component.
- the combined state refrigerant is introduced into the refrigerating evaporator 15.
- the heat exchange of the refrigerant with the cool storage material causes the temperature of the cool storage material in the cool packs 5 to be reduced due to the evaporation heat of the refrigerant at the cool storage evaporator 14.
- the gas and liquid combined states of refrigerant is, then, introduced into the refrigerating evaporator 15, so that a heat exchange with the refrigerant occurs with respect to the inside air flow generated by the inside fan 31, so that the refrigerant is evaporated and is introduced into the accumulator 16.
- the gaseous state refrigerant is separated from the liquid state refrigerant and is introduced into the compressor 11, thereby repeating the refrigerating cycle.
- the air, cooled at the refrigerating evaporator 15 by means of the evaporating heat of the refrigerant, is discharged from the duct 28-1 of the cooling device into the space inside the refrigerating compartment 3.
- the evaporating temperature of the refrigerant at the cool storage evaporator 14 as well as the refrigerating evaporator 15 is reduced as shown in a line m in Fig. 6B.
- the temperature inside the refrigerating compartment 3 is also reduced as shown by a line n in Fig. 6A.
- the control panel 8 causes the inside fan motor 32 to be made OFF, which prevents the inside fan 31 to be rotated, while maintaining the outside fan 33 as well as the elector-magnetic clutch 18 to be operated, so that the refrigerating cycle is continued, thereby executing the cool storage operation.
- this cool storage operation an air flow contacting with the refrigerating evaporator 15 is stopped, thereby reducing the heat exchange capacity at the evaporator 15. In other words, the refrigerating evaporator 15 does not substantially act to evaporate the refrigerant.
- the temperature of the gaseous refrigerant at the refrigerating evaporator 15 is reduced.
- the pressure at the temperature sensitive tube 23 opened to the diaphragm actuator 24-1 via the conduit 24 causes the degree of the throttle of the valve member 21 of the expansion valve 21 to be reduced, thereby reducing the amount of the refrigerant introduced into the cool storage evaporator 14.
- the evaporating temperature of the refrigerant at the cool storage evaporator 14 is, from the first evaporating temperature Te1 (-25°C) at the timing t1 when the inside fan motor 32 is made off, further reduced to a second evaporating temperature Te2 (-35°C), as shown by a curve o in Fig. 6B.
- Te1 25°C
- Te2 -35°C
- the cool storage material in the cool storage packs 5 covering the circular tube 25 is further cooled, thereby executing cool storage operation.
- the inside temperature is increased as shown by a curve p in Fig. 6A.
- the inside temperature Ta in the refrigerating compartment 3 is increased to the second predetermined value T2 (-16°C), the inside fan motor 32 is again made ON, so that the inside fan 31 generates a flow of the air inside the refrigerating compartment 3 induced by the convection thereby commencing the refrigerating operation.
- T2 16°C
- a refrigerating operation by making ON the electro-magnetic clutch 18 and a rest (cool keeping) operation by making OFF the clutch 18 are repeated for controlling the temperature of the refrigerating compartment.
- the refrigerating operation is continued to a time t4, where the temperature of the refrigerant is reduced to a first temperature T1 Then the clutch 18 and the fan motor 32 are made OFF, so as to commence the cool keeping operation.
- the latent heat of the cool storage material in the packs 4, when it is molten, can prevent the inside temperature form being quickly increased.
- a stoppage of the operation of the internal combustion engine 20 causes the refrigerating unit 4 to be de-energized, which causes the inside temperature of the refrigerating compartment 3 to be increase, thereby the cool storage material to be molten.
- the melting latent heat of the cool storage material in the cool storage packs 5 causes the cool keeping operation of the refrigerating compartment to be executed.
- the refrigerant flow switching valve 17 is made ON, when the defroster switch is made ON by an operator or, during the refrigerating or the cool storage operation of the refrigerating operation, a predetermined condition is detected such that a predetermined value of the evaporating pressure or the temperature of the refrigerating evaporator 15 is detected or a predetermined duration of, for example, 1 hour of the refrigerating or cool storage operation is obtained.
- a switching on of the valve 17 causes the flow of the refrigerant to be switched from the first refrigerating passageway 29 to the second refrigerant flow passageway 30 as shown by the arrow b in Fig. 1. As a result, the defrosting operation is commenced.
- the refrigerant of a high temperature or high pressure is directly introduced into the refrigerant evaporator 15 via the second refrigerating passageway 30.
- the surface of the refrigerant evaporator 15 is defrosted or de-iced.
- the cool storage evaporator 14 and the refrigerating evaporator 15 are connected in series, and the temperature sensitive expansion valve 13 is for controlling the degree of the throttle in accordance with the change in the temperature at the cutlet of the refrigerating evaporator 15. Furthermore, the melting temperature of the cool storage material in the cool storage packs 5 of the cool storage evaporator 14 is determined so that it is the same degree as the evaporating temperature, for example -25°C, of the refrigerant in the refrigerating evaporator 15 when the temperature inside the refrigerating compartment 3 is reached to the first predetermined value.
- a cooling of the cool storage material having such a value of the melting temperature by the cool storage evaporator 14 prevents the cool storage material in the cool storage evaporator 14 from being frozen, thereby preventing the cool storage material from being over-loaded. Furthermore, in the cool storage operation, the throttling operation of the temperature sensitive expansion valve 13 can maintain a suitable difference between the temperature of the cool storage material and the evaporating temperature of the refrigerant in the cool storage evaporator 14. As a result, in the refrigerating system for the refrigerated vehicle, the refrigerating operation and the cool storage operation, which take place alternately, can be executed efficiently.
- the refrigerating evaporator 15 downstream from the cool storage evaporator 14, the refrigerating evaporator 15 is connected in series, and the second refrigerant passageway 30 connects the outlet 11-1 of the compressor 11 directly with the inlet of the refrigerating evaporator 15.
- the gaseous refrigerant of a high temperature and pressure from the outlet of the compressor 11 is introduced into the refrigerating evaporator 15 while by-passing the condenser 12, the expansion valve 13 and the cool storage evaporator.
- the cool storage material in the cool storage packs 5 of the cool storage evaporator 14 is prevented from being melted.
- Fig. 7 shows a second embodiment of the cool storage evaporator 14 of the refrigerating system for a refrigerated vehicle.
- the cool storage evaporator 14 includes a container 52 and a serpentine arrangement of the refrigerant pipe 53.
- the container 52 stores the cool storage material 51 with which the refrigerant pipe 53 is contacted. This construction is advantageous in that the weight of the device is reduced.
- the refrigerant pipe 53 is, on its outer surface, formed with fins 54 of a spiral fin structure or plate fin structure for increasing a heat exchanging capacity.
- the refrigerating pipe 53 has a first end 55 for receiving the refrigerant from the expansion valve 13 and a second end 56 for discharging the refrigerant into the refrigerating evaporator 15.
- the cool storage evaporator of a refrigerating system for a refrigerated vehicle includes a container 52 similar to as that in the second embodiment in Fig. 7, in which container 52 capsules 57 made of resin or metal material for sealingly storing therein the cool storage material are filled.
- the temperature operated automatic expansion valve 13 includes a valve casing 21, a temperature sensitive unit 22, which is constructed by a thermo-sensitive tube 23 and a capillary tube 24, a valve rod 71, a first and second ball shaped valves 61 and 62 fixed on the valve rod 71 and arranged movably in the valve casing 21 so as to create variable throttles 65 and 66, respectively, a diaphragm mechanism 67 for generating a pressure force in the valve rod 71, a coil spring 63 for urging the valve rod 71 toward the diaphragm mechanism 67, a spring seat 73, which receives at its first end the second ball shaped valve 62 and is connected at its second end to the upper end of the spring, and an adjusting screw 74 to which the lower end of the spring 63 rests.
- the valve casing 21 is formed from a metal material such as brass and is formed therein with a passageway 64 of a generally L-shape and for a refrigerant.
- the L-shaped passageway 64 has an upstream end connected to an outlet to the condenser 12 for receiving the liquid state refrigerant as shown by an arrow r and a downstream end connected an inlet of the cool storage evaporator 14 for discharging the refrigerant thereto as shown by an arrow s.
- the first and second orifices 65 and 66 are located in series in the refrigerant passageway 64.
- the first orifice 65 on the upstream side has an inner diameter which is larger than that of the second orifice 66 on the downstream side.
- the inner diameters of the first and second orifices 65 and 66 are such that the first and second balls 61 and 62 are freely movable in the orifices 65 and 66, respectively, without contacting with the inner walls of the orifices 65 and 66, respectively.
- the diaphragm actuator 67 is constructed by a lower diaphragm cover 67-1 connected to a valve casing 21, an upper diaphragm cover 67-2 connected to the lower diaphragm cover 67-1, a diaphragm 70 between the upper and lower diaphragm covers 67-1 and 67-2, and a diaphragm stopper 72 concentrically connected to the rod 71.
- An upper diaphragm chamber 68 is formed on an upper side of the diaphragm 70, while a lower diaphragm chamber 69 is formed on a lower side of the diaphragm 70.
- the upper diaphragm chamber 68 is connected to the capillary tube 24.
- the casing 21 is formed with an opening 21a having a first end opened to the lower chamber 69 and a second end connected to a pressure equalization conduit 60, which is connected to a refrigerating pipe in Fig. 1 at a location between the temperature operated automatic valve 13 and the cool storage evaporator 14, so that the pressure in the lower chamber 69 corresponds to a lower pressure, i.e., an evaporating pressure in the refrigerating recirculation system.
- the temperature sensitive tube 23 Inside the temperature sensitive tube 23, an amount of a gaseous refrigerant, which is the same refrigerant as that recirculated in the refrigerating system, is sealingly stored. Furthermore, as explained with reference to Fig. 1, the temperature sensitive tube 23 is arranged to be in side by side contact with the refrigerant tube at the outlet of the refrigerant evaporator 15. As a result, a pressure inside the temperature sensitive tube 23, i.e., the pressure in the upper chamber 68 is varied in accordance with the temperature of the refrigerant flowing in the refrigerating recirculation system.
- a pressure corresponding to the pressure at the thermo-sensitive tube is generated in the upper chamber 68, which causes the diaphragm 70 to be moved downwardly. Furthermore, a pressure corresponding to the lower pressure in the refrigerating system is generated at the lower diaphragm chamber 69, which causes the diaphragm 70 to be moved upwardly. Furthermore, the spring 63 generates a force for moving the diaphragm 70 upwardly.
- the ball shaped valves 61 and 62 on the shaft 71 connected to the diaphragm 70 are located at respective positions, which are determined by a balance between the downwardly directed force by the pressure at the upper chamber 68 and the upwardly directed forces by the pressure at the lower chamber 69 and by the spring 63, and which determine the degrees of the throttle at the orifices 65 and 66, respectively.
- a screw adjustment of the screw 74 causes the latter to be moved axially, thereby varying the spring force of the spring 63, i.e., the pressure for making the second ball valve 62 open.
- a refrigerating operation for reducing the inside temperature of the refrigerating compartment causes the refrigerating load to be increased, thereby increasing the temperature of the gaseous refrigerant at the outlet of the refrigerant evaporator 15.
- the gaseous refrigerant in the temperature sensitive tube 23 is subjected to expansion, so that the pressure at the upper diaphragm chamber 68 is higher than the pressure at the lower diaphragm chamber 69, which causes the operating rod 71 to be moved downwardly.
- the first ball valve 61 takes a first position as shown in Fig. 1, where the first ball valve 61 is downwardly spaced from the first orifice 65.
- the degree of the throttle of the first orifice is small, which prevents the refrigerant passing through the orifice 65 from being subjected to an adiabatic expansion.
- the liquid state refrigerant introduced into the refrigerant passageway 64 as shown by the arrow r from the condenser is passed through the first orifice 65 as shown by an arrow t without being subjected to the adiabatic expansion, and is introduced into the second orifice 66 in the liquid state.
- the second ball shaped valve 62 is, as shown in Fig.
- the mist state refrigerant flowing into the refrigerant evaporator 15 is subjected to heat exchange with the inside air flow generated by the inside fan 31 as rotated by the electric motor 32, so that the refrigerant is evaporated under a super heated condition at the outlet of the refrigerant evaporator 15.
- the degree of opening of the second orifice 66 is such that a large amount of the refrigerant passing through the orifice 66 suitable for the high load operation is obtained, which allows the inside air in the refrigerating compartment 3 to be effectively cooled, thereby reducing the inside temperature of the refrigerating compartment.
- a cool storage operation is obtained by making OFF the inside fan motor 32, while maintaining the ON conditions of the electromagnetic clutch 18 as well as the outside fan motor 34.
- the stoppage of the inside fan 31 in this cool storage operation causes the heat exchange to be reduced between the refrigerant in the refrigerant evaporator 15 and the inside air in the refrigerating compartment, thereby substantially preventing the refrigerant from being evaporated.
- the reduction of the refrigerating load in the refrigerating compartment 3 causes the temperature of the refrigerant to be reduced at the outlet of the refrigerant evaporator 15, which causes the gas in the temperature sensitive tube to be compacted.
- the pressure at the upper diaphragm chamber 68 is reduced toward the pressure at the lower diaphragm chamber 69, so that the diaphragm 70, i.e., the operating rod 71 is moved upwardly to a position as shown in Fig. 10.
- the first ball shaped valve 61 is located to be vertically aligned with the first orifice 65
- the second ball shaped ball valve 62 is located vertically aligned with the second orifice 66.
- the throttling operation by means of the second ball shaped valve 62 causes the evaporating pressure to be reduced in the refrigerant recirculating system, on one hand, and the recirculated amount of the refrigerant to be reduced, on the other hand.
- the refrigerant passed through the first orifice 65 is subjected to an adiabatic expansion, thereby causing the refrigerant to be in a gas/liquid combined state.
- the state of the refrigerant introduced into the second orifice 66 is under the gas/liquid combined state rather than the liquid state. Due to the combined state of the refrigerant at the second orifice 66, the flow area is increased while maintaining the same amount of the recirculated refrigerant.
- the second ball valve 62 can be operated in a range for controlling the degree of the superheating of the refrigerant.
- the temperature operated expansion valve of a conventional structure employed in the first embodiment in Fig. 1 has a structure as shown in a block b , where only a signal orifice a is provided. Contrary to this, the evaporating temperature is different between the cool storage evaporator 14 and the refrigerant evaporator 15. In this case, the volume as well as the opening pressure of the conventional temperature sensitive valve can be set for the higher evaporating temperature at the refrigerant evaporator 15. In this case, switching to the cool storage operation due to a reduced load causes the temperature sensitive valve to throttle the orifice, so as to make the system to respond to a small necessary amount of the recirculated refrigerant.
- a setting of the volume as well as the opening pressure of the conventional temperature sensitive valve suitable for the lower evaporating temperature at the cool storage evaporator 14 causes the recirculating amount of the refrigerant to be reduced, which causes the cooling capacity of the system to be reduced.
- a single orifice structure b is disadvantageous in that a requirement for stable control during a low load condition (cool storage operation) and a desired cooling capacity during a high load condition can not be harmonized.
- the first and second orifices 65 and 66 controlled by the ball shaped valves 61 and 62, respectively, are provided.
- Such a construction of the fourth embodiment can harmonize the above mentioned contradictory requirements. Namely, during the refrigerating operation wherein the lift of the valve is large, the second orifice 62 functions to vaporize the refrigerant, which is effective for preventing the cooling down capacity from being reduced.
- the first orifice 65 functions to vaporize the refrigerant, downstream of which the second orifice 66 as well as the second valve 62 are located as shown by a block 13 in Fig. 11.
- the second ball valve 62 can obtain a gradual reduction of the recirculated amount with respect to a change in the degree of the throttle as shown by x' in the solid curve in Fig. 11. In other words, the second valve 66 is moved in a range wherein a degree of superheat of the refrigerant is controlled, thereby reducing the amount of hunting to as small as H2 for the same fixed valve lift y.
- a fifth embodiment of the present invention will be explained with reference to Figs. 12 and 13.
- Fig. 12 showing a refrigerant recirculating system, wherein a temperature operated automatic expansion valve 13, of a usual type including, therein, a second throttle portion, and an electromagnetic valve 76 are arranged on the refrigerant tube at a location between the outlet of the condenser 12 and the inlet of the temperature operated expansion valve 13.
- a temperature operated automatic expansion valve 13 of a usual type including, therein, a second throttle portion, and an electromagnetic valve 76 are arranged on the refrigerant tube at a location between the outlet of the condenser 12 and the inlet of the temperature operated expansion valve 13.
- the electromagnetic valve 76 includes a housing 78 having refrigerant passageways 77 and 77-1, a valve opening 79 between the passageways 77 and 77-1 and by-pass port 75 by-passing the valve port 79, the electromagnetic valve 76 further includes a needle valve 80 for selectively opening or closing the valve port 79, a valve seat 84 and a electromagnetic actuator 81 for operating the needle valve 80.
- the electromagnetic actuator 81 is constructed by a plunger 81-1 connected to the needle valve 80, a spring 83 for generating a spring force for causing the needle valve 80 to be seated on the valve seat 84 and a electromagnetic coil 82 for generating an electromagnetic force for causing the plunger 81-1 to be moved against the force of the spring 83.
- the electromagnetic coil 82 is, under the low load condition such as a cool storage operation, de-energized, so that the needle valve 80 shuts off the valve port 79.
- the flow of the refrigerant from the condenser 12 to the expansion valve 13 is occurred by way of the by-pass port 75.
- the refrigerant passing through the by-pass port 75 of a reduced dimension is subjected to an adiabatic expansion so that a gas/liquid combined state of the refrigerant is obtained.
- the electromagnetic coil 82 is energized, so that the plunger 81-1 connected to the needle valve 80 is moved upwardly against the spring force of the spring 83.
- the refrigerant passes the valve port 79 of an increased dimension while maintaining the liquid state, thereby increasing a recirculated amount of the refrigerant.
- the fifth embodiment operates in the same way as the fourth embodiment in that recirculated amount of the refrigerant is controlled in accordance with the refrigerating load.
- the temperature operated expansion valve 13 includes a disk 85 as a first valve and a ball 62 as a second valve.
- a first seat plate 87 includes a central opening 88 through which the valve shaft 71 passes, and a plurality of circumferentially spaced orifices 65.
- Another seat plate 86 is located downstream from the first plate 87 and is formed with an orifice 66.
- a valve 85 of a disk shape faced with the opening 88 is fixedly connected to the shaft 71.
- a valve 62 of a ball shape faced with the orifice 66 is fixedly connected to the valve shaft 71.
- the central communication opening 88 has an effective opening area larger than that of the second orifice 66. Furthermore, the first orifice 65 in the plate 87 has an effective area which is smaller than the effective area of the second orifice 66. AS a result, when the refrigerant passes through the first orifice 65, an adiabatic expansion occurs in the refrigerant.
- a low load operation caused by the cool storage operation causes the diaphragm 70 to be moved upwardly to take a position as shown in Fig. 14, where the plate shaped valve closes the central opening 88, so that the refrigerant from the condenser introduced into the passageway 64 is passed through the first orifices 65, whereat the refrigerant is subjected to adiabatic expansion, thereby obtaining a gas/liquid combined state refrigerant, which is introduced into the second orifice 66.
- the second valve 62 of the ball shape controls the flow of the gas/liquid combined state refrigerant from the first orifice 65.
- a high load operation caused by the refrigerating operation causes the diaphragm 70 to be moved downwardly to take a position as shown in Fig. 15, where the plate shaped valve 85 is displaced from the seat plate 87, thereby opening the central opening 88, so that an increased amount of the refrigerant from the condenser 12 introduced into the passageway 64 is passed through the central opening 88 of an increased dimension while maintaining a liquid state condition.
- a similar operation as that in the fourth embodiment in Figs. 9 to 11 is obtained.
- Fig. 16 shows a refrigerated vehicle provided with a refrigerating system includinq a cool storage evaporator 14.
- the cool storage evaporator 14 is arranged on an upper part of the refrigerating compartment 3, and is constructed by cool storage packs 5 formed as containers for storing a cool storage material made of a resin of an increased heat conductivity and by a serpentine tube 90 of a circular cross sectional shape of an outer diameter of 15.8 mm.
- the serpentine tube 90 extends in a vertical plane and is constructed by straight pipe portions and U-shaped connecting portions, which are arranged alternately.
- Opposite pairs of the cool storage packs 5 are provided, between which the straight portions of the serpentine tube 90 are sandwiched, so that the straight and U-shaped portions are partly downwardly projected out of the cool storage packs 5.
- the straight portions and the U-shaped portions, which are not sandwiched by the cool storage packs 5, construct a heat absorber 91 (lower section), while the straight portions, which are sandwiched by the cool storage packs, construct a heat emitter section 92 (upper section).
- a value of length L of the heat absorbing section 91 from the bottom end of the cool storage packs 5 is in a range between 0.6m to 0.7m.
- the circular cross sectional tube 90 has an inlet 93 for the introduction of the refrigerant and an outlet 94 for the discharge of the refrigerant.
- the heat absorber 91 of the rounded tube 90 may be the type with fins so as to increase a heat exchanging capacity.
- the heat absorber 91 of the rounded tube may be the one with spine fins so as to increase a heat conduction area, thereby improving a cool keeping capacity.
- FIG. 17 illustrates a condition of the refrigerant in the rounded tube under the a cool keeping operation. Namely, at the heat absorber 91 located outside the cool storage packs 5, heat from a low temperature inside air at, for example, -10°C is absorbed by the liquid state refrigerant in the bottom of the tube 90, thereby gasifying the refrigerant.
- the gasified refrigerant is moved upwardly toward the heat emitter 92 as shown by arrows w .
- the tube 90 is sandwiched by the cool storage packs 5, in which the cool storage material is under a refrigerating condition of, for example, temperature of -25°C.
- the cool storage material is condensed and liquidized, so that a heat is emitted to the cool storage packs 5, thereby obtaining a so-called heat pipe effect.
- a refrigerated vehicle In a situation where an emission of an exhaust gas or an operating noise is strongly restricted, it is necessary for a refrigerated vehicle to be provided with means for keeping a low temperature inside the refrigerating compartment under a stopped condition of an internal combustion engine of the refrigerated vehicle.
- a technic has been proposed, where a cool storage material sealingly stored in a metal container is frozen at night by using an outside electric power source. During transportation by a refrigerated vehicle, latent heat generated when the cool storage material is melted is used for keeping a low temperature inside the refrigerating compartment without operating the refrigerating system.
- this prior art is disadvantageous due to an increased weight and manufacturing cost due to the use of the metal container.
- the container is made of a plastic material.
- a container made of a plastic material is disadvantageous due to a large thermal resistance, thereby reducing a cool keeping capacity when compared with the metal container.
- the rounded tube 90 of the heat accumulating evaporator 14 is constructed so as to function as a heat pipe. Due to the employment of the heat pipe construction, an increase in the heat absorbing capacity is obtained, thereby providing a desired cool keeping operation, even if the container for constructing the cool storage packs 5 is made of plastic material.
- the rounded tube 90 is arranged so that its extends vertically along the length thereof in order to construct the heat absorber as constructed to be function as a heat pipe.
- a refrigerant pipe extending horizontally can obtain a similar heat pipe function for executing the cool keeping operation so long as the heat emitter of the cool storage packs 5 is not inclined downwardly with respect to a horizontal direction.
- a solid curve shows a change in a temperature inside the refrigerating compartment after the completion of the freeze for the construction of the seventh embodiment
- a dotted curve shows a result for a conventional structure.
- the present invention can maintain an inside temperature lower than -5°C even after lapse of 60 minutes. Contrary to this, in the conventional structure, the inside temperature is higher than -5°C when 60 minutes has lapsed from the completion of the freeze. In short, an improvement in the cool keeping capacity is obtained by the structure of the present invention.
- Fig. 19 shows a cool storage evaporator 14, in the eighth embodiment, which is arranged on a side wall the refrigerating compartment on a refrigerated vehicle.
- the cool storage evaporator 14 includes six cool storage packs 5 each including a container made of a plastic material of an increased heat conductivity for storing therein a cool storage material, and a rounded tube 35 including vertically spaced straight portions 95 extending horizontally and looped portions 95-1 connecting the straight portions 95 with each other.
- a construction of the rounded tube 90 in Fig. 16 can be employed in order to improve the heat conducting capacity as well as the refrigerating capacity.
- each pack 5 is constructed by a first and a second members 5-1 and 5-2, which are faced with each other by way of the straight portions of the rounded tube 95, thereby obtaining the structure. Furthermore, in the vertical direction, two packs are arranged, while, in the horizontal direction, three packs are arranged. In Fig. 19, only one pack is shown, and remaining five packs are not shown for the sake of the simplicity. Furthermore, an attachment device 200 is provided for fixedly connecting the cool storage evaporator 14 to an inner side wall of the refrigerating compartment 3.
- the attachment device 200 includes two vertically extending ended fixing members 201, two vertically extending intermediate fixing members 202, six vertically extending rear side fixing members 203, three vertically extending front side fixing members 204 and fixing members 205 such as screws or bolts for connecting the fixing members 201, 202, 203 and 204 with each other and for connecting the members to the side wall of the refrigerating compartment 3.
- Each of the end fixing members 201 is made from a metal plate of a substantially C-cross sectional shape and is formed with vertically spaced openings, to which the straight portions of the tube 5 are inserted, respectively, so that the U-shaped portions 95-1 are projected out of the member 201. Furthermore, the end fixing member 201 is further formed with holes 211 and 212 for allowing the screws or bolts to be passed therethrough. As shown in Fig. 9, the rounded hole 211 has an inner diameter larger than that of the rounded hole 212.
- the intermediate fixing members 202 are arranged between the end fixing members 201 and each is formed as a metal plate of a substantially Z-cross sectional shape. Furthermore, the intermediate fixing member 202 forms vertically spaced holes, through which the straight portions of the tube 5 are inserted. Finally, the intermediate fixing member 202 forms rounded holes 213, through which the screws or bolts 205 are inserted.
- the rear side fixing members 203 are arranged between the cool storage evaporator 14 and the side wall of the refrigerating compartment 3 and are, each, constructed by a metal plate of a cross-sectional shape as shown in Fig. 19.
- three vertical pairs of fixing members 203 which are arranged symmetric and contacted along their faced vertical edges, are provided. These vertical pairs are arranged between the plates 201 and 213, between the plates 213 and between the plates 213 and 212, respectively.
- the rear side fixing member 203 forms rounded holes 214 and 215 for receiving the screws or bolts 205.
- the front side fixing members 204 are arranged so as to be extended vertically and are arranged between the plates 201 and 213, between the plates 213 and between the plates 213 and 212, respectively, so that the front side fixing members 204 face corresponding pairs of the rear side fixing members 203. Furthermore, between front side fixing member 204 and the pair of the rear side fixing members 203, two vertically spaced cool storage packs 5 are arranged, each pack includes the first and second members 5-1 between which the four straight pipe portions are arranged. Finally, the front side fixing member 204 forms rounded holes 216 and 217 for the passage of the screws 205.
- the screw members 205 are, at the final stage of a mounting process, introduced into the holes 216 of the front plates 204 and then into the holes 214 of the rear plates 203 and introduced into the holes 217 of the front plates 204 and then into the holes 215 of the rear plates 203, so that the screw members 205 can be tightened. Due to such a tightening force, the cool storage packs 5 are fixed between the faced front plates 204 and the rear plates 203, while the refrigerating tubes 95 are held by the cool storage packs 5, thereby obtaining the cool storage evaporator assembly. Then, the screw 205 are inserted to the holes 211 and then to the hole 212 of the upright members 201. Furthermore, the screws 205 are inserted to the holes 213 of the upright members 202, so that the cool storage evaporator assembly is connected to the inner side wall of the refrigerating compartment 3.
- Figs. 20 and 21 show a cool storage evaporator in a ninth embodiment.
- the cool storage evaporator 14 in this embodiment is connected to a ceiling 300 of the refrigerating compartment 3.
- Each pack 5 is constructed by a container for storing therein a cool storage material.
- the container has at its bottom surface grooves 5-3 along the length thereof.
- the cool storage evaporator 14 is further included with a rounded tube 95 of a serpentine shape for cooling the cool storage material in the packs 5, a resilient plate 302 to be arranged between the packs 5 and the ceiling 300, and a box shaped casing 303 with opened top for storing therein the packs 5, the tube 95 and the resilient plate 312.
- the resilient plate 312 is formed generally as a rectangular plate shape constructed by a sponge, an air cushion, rubber or a plate spring.
- the resilient plate 302 is, as shown in Fig. 20, constructed as a flat plate portion 311 for urging the array of the packs 5 toward the bottom of the casing 303, a pair of side walls 312 extending along the width of the flat plate portion 311 and a pair of side walls 313 extending along the length of the flat plate portion 311.
- the side walls 312 and 313 extend downwardly so as to be sandwiched between the casing 303 and the packs 5.
- the box shaped casing 303 with bottom is made from metal plate of a high heat conductivity by pressing.
- the casing 303 is formed with opposite walls 321 extending along the width, opposite walls 322 extending along the length, and a bottom wall 323 of an elongated rectangular shape.
- the casing 303 is further formed with flanges 324 extending horizontally from the side walls 321 at their top portions.
- the flanges 324 are formed with rounded holes 324-1 for screws or bolt for connecting the casing the top wall 300 of the refrigerating compartment 3.
- the bottom wall 323 of the casing 303 is formed with groove 325 of a arc-shaped cross-sectional shape.
- the groove 325 extends along the serpentine shape of the tube 95 constructed by the straight portions and the U-shaped portions, so that the tube 95 is, at its lower side, fitted to the groove 325 as shown in Fig. 21.
- the side wall 321 of the casing 303 is formed with a hole 326 for inserting the inlet part of the tube 95 and a hole 327 for inserting the outlet part of the tube 95.
- the ninth embodiment in Figs. 20 and 21 is advantageous in that the number of parts are reduced, on one hand, and a work for mounting is reduced, on the other hand. Furthermore, a resilient mounting of the cool storage packs 5 are realized, which is advantageous in preventing the packs from being damaged during the mounting. Namely, in the ninth embodiment, the flanges 324-1 of the casing 303 are directly connected to the inner top wall 300 of the refrigerating compartment 3 without using any additional parts, such as the upright members 201 to 204 in the eighth embodiment. Thus, the cost is reduced in view of the fact that the number of parts is reduced and that the work for the mounting is reduced.
- the resilient plate 302 exists between the ceiling wall 300 and the cool storage packs 5.
- the resilient plate 302 is deformed, so as to absorb the expansion, thereby preventing the packs 5 from being damaged.
- the resilient member 302 functions, also, to absorb a vibration generated due to the running of the refrigerated vehicle, thereby preventing the vibration from being transmitted to the cool storage packs 5, thereby preventing the plastic containers of the packs 5 from being damaged.
- Fig. 23 shows a control panel of the tenth embodiment, which includes, in addition to the elements shown in Fig. 4 with reference to the first embodiment, a relay including a coil 47 and a normally opened relay switch 48 arranged parallel to the relay switch 45 of the relay 41 for controlling an on-off operation of the inner fan motor 32.
- a fixed resistor 49 is arranged in series to the relay contact 45.
- the resistor 49 is for obtaining a low rotational speed of the inside fan motor 32, i.e., a low air flow amount L0 by the inside fan 31 when the relay switch 45 is made ON while the relay switch 48 is made OFF. Contrary to this, when the relay switch 48 is made ON, the resistor 49 is shunted, which causes the rotational speed of the inside fan motor 32 to be increased, thereby obtaining a large air flow amount H1. Stoppage of the inside fan motor 32 is obtained when both of the relay switches 44 and 45 are made OFF.
- a semiconductor switching circuit may be used for operating the inside fan motor 32. Furthermore, in place of obtaining a step-like change in the rotational speed of the fan motor 32 (an air flow amount by the fan 31) by the step-like change in the electric current in the fan motor 32 due to the fixed resistor 49, a continuous change of the rotational speed of the inside fan motor 32 (continuous change in the air flow amount of the inside fan 31) can be obtained by a continuous change in the electric current by a continuously variable resistor.
- step S11 a first, a second and a third values preset temperatures T1, T2 and T3 are calculated in accordance with the set temperature set by the inside temperature set switch. Then, the routine flows into steps S4 and S5.
- the inside temperature Ta detected by the inside temperature sensor 37 would be higher than a third predetermined value T3 which is equal to the set inside temperature Ts plus predetermined value ⁇ such as 10°C.
- the cooling down operation would cause the routine to go to step S14, where the electromagnetic clutch 18 of the compressor 11 and the outside fan motor 34 are made ON, while the flow switching valve 17 is made OFF.
- the relay coil 41 is de-energized to cause the switch 45 to be made OFF, while the relay coil 47 is energized to make switch 48 ON, so that an increased electric current is obtained, thereby obtaining a high rotational speed Hi of the inside fan motor 32.
- the inside temperature Ta is lower than the third predetermined value T3, which causes the result of the judgement at step S12 to be No, so that the routine goes to step S13, where the electromagnetic clutch 18 of the compressor 11 and the outside fan motor 34 are made ON, while the flow switching valve 17 is made OFF.
- the relay coil 41 is energized to cause the switch 45 to be made ON, while the relay coil 47 is de-energized to make switch 48 OFF.
- a reduced electric current is obtained due to the resistor 49, so that a low rotational speed Lo of the inside fan motor 32 is obtained.
- the result of determination of NO at step S6 may directly lead to step S9.
- the larger air flow amount Hi larger than the normal value Lo, is obtained when the system is under a cool down operation.
- the temperature inside the refrigerating compartment 3 is higher than the set temperature Ts plus the predetermined value, i.e., the inside temperature Ta is higher than the set temperature T3.
- the evaporating temperature of the refrigerant at the refrigerant evaporator becomes larger than the melting point of the cool storage material.
- curve (a) is a Mollier diagram during the normal refrigerating operation, where a low speed rotation (a low flow amount L0) of the inside fan 31 is obtained.
- Curve (b) shows a Mollier diagram during the cool storage operation. In this case, the pressure is lowered and a major portion k of the increase in the enthalpy during the evaporating periods is occupied by the cool storage operation.
- Curve (c) shows a Mollier diagram during a high load operation, where a rotational speed of the fan is high, i.e., the air flow amount is as large as L1. In this case, the pressure of the refrigerant is increased and the cool storage material is melted, which causes the enthalpy change n during the evaporating period to be increased.
- the present invention can also be used for a refrigerating system for a stationary type container or refrigerator or for other any types of appliances with refrigerating capability.
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Abstract
A refrigerating system having a cool storage evaporator 14 and a refrigerating evaporator 15 arranged in series. The cool storage evaporator 14 includes a rounded cross sectioned tube 25 which is in contact with a cool storage material stored in containers. The cool storage material has a melting temperature which substantially corresponds to a predetermined value of evaporating temperature of a refrigerant when the temperature inside a refrigerating compartment is reduced to a predetermined value for switching from a refrigerating operation to a cool storage operation. During the refrigerating operation, the cool storage material is prevented from being frozen, thereby preventing a load to the cool storage material. During a cool storage operation obtained by stopping the operation of an inner fan 31, a throttling of a temperature operated expansion valve 13 maintains desired temperature difference between the temperature of the cool storage material and an evaporating temperature of the refrigerant at the cool storage evaporator 14.
Description
- The present invention relates to a refrigerating system and more particularly to a refrigerating system for a refrigerating compartment for a refrigerated vehicle, which system includes an evaporator for a cool storage area and an evaporator for a refrigeration area.
- Known in a prior art is a refrigerating system for a refrigerated vehicle with a cool storage capability, as disclosed in Japanese Unexamined Patent Publication No. 64-6654, which apparatus includes a refrigerating device for executing a refrigerating cycle, an outer blower and an inner blower. The refrigerating unit includes a compressor, a condenser, temperature responsive automated expansion valves, an evaporator for a refrigeration area, an evaporator for a cool storage area, and a gas-liquid separator or accumulator. The first temperature responsive automated valve has a diaphragm opened to a temperature sensitive tube at an outlet of the refrigerating evaporator via a capillary conduit, so that the size of an orifice, i.e., the pressure amount of the refrigerant introduced into the gas/liquid separator, is controlled in accordance with the temperature of the refrigerant at the outlet of the evaporator. Similarly, the second temperature responsive automated valve has, also, a diaphragm opened to a temperature sensitive tube at an outlet of the cool evaporator via a capillary conduit, so that the size of an orifice, i.e., the pressure amount of the refrigerant introduced into the gas/liquid separator, is controlled in accordance with the temperature of the refrigerant at the outlet of the cool storage evaporator. The refrigerating evaporator and the cool storage evaporator are arranged in parallel. The prior art refrigerating system is further provided with switching valves, which are repeatedly and intermittently operated between open and closed conditions, so as to obtain a refrigerating operation and a cool storage operation. When the engine is stopped or an output power of the engine is insufficient for obtaining a desired rotational speed due to the running of the automobile in a traffic jam, the cool storage material in the cool storage evaporator melts, which is effective for maintaining a desired low temperature inside the refrigerating compartment.
- As explained above, the repeated opening or closing operation of the switching valves in the prior art (Japanese Unexamined Patent Publication No. 64-6654) allows the refrigerating operation and the cool storage operation to be effectively executed. However, the parallel arrangement of the refrigerating evaporator and the cool storage evaporator necessitates two thermo-sensitive automated operation valves as well as two switching valves, which causes the number of the parts to be increased, thereby increasing the production cost. Furthermore, in the prior art construction, during the cool storage operation, melting of the cool storage material is commenced from its outer portion, which can easily contact the air in the refrigerating compartment. In other words, melting of the cool storage material located at the inner side adjacent to the tube of the cool storage evaporator is less likely. As a result, effective use of the latent heat of fusion of the cool storage material cannot be obtained.
- An object of the present invention is to provide a refrigerating system of a reduced cost capable of obtaining a refrigerating operation as well as a cool storage operation, which are effective.
- Another object of the present invention is to provide a refrigerating system capable of preventing the cool storage material from being melted during a de-frosting operation.
- Still another object of the present invention is to provide a refrigerating system capable of obtaining an effective refrigerating operation while obtaining an increased performance during a cool-down operation.
- Further another object of the present invention is to provide a refrigerating system capable of preventing a cool keeping operation from being affected by increasing the heat absorbing performance of the refrigerant at the cool storage evaporator.
- Still further object of the present invention is to provide a refrigerating system capable of obtaining an increased cooling performance at an initial phase after a cool storage operation.
- According to the present invention, a refrigerating system is provided which comprises:
a heat insulated chamber;
means for generating a flow of air recirculated in the chamber;
means arranged in the chamber for holding an amount of cool storage material;
a compressor for compression of a refrigerant;
a condenser for receiving the compressed refrigerant from the compressor;
an expansion valve for reducing the pressure of the refrigerant from the condenser;
a first evaporator for receiving the refrigerant of the reduced pressure for cooling the cool storage material;
a second evaporator for receiving the refrigerant of the reduced pressure for cooling the air flow recirculated in the chamber;
a closed passageway for the refrigerant being constructed by the compressor, the condenser, the temperature sensitive expansion valve, the first evaporator and the second evaporator;
said expansion valve being of a type capable of controlling the amount of the recirculated refrigerant in accordance with the temperature of the refrigerant at an outlet side of the second evaporator;
said first and second evaporators being arranged in series with each other;
the expansion valve being arranged in the closed passageway at a location upstream from the evaporators, and;
means for obtaining switching between a refrigerating condition where the flow of the recirculated air by means of the air flow generating means is obtained and a cool storage condition where the flow of the recirculated air by means of the air flow generating means is cancelled. Due to the series arrangement of the cool storage evaporator and the refrigerating system, a reduction of cost is obtained because of a reduced number of the parts, while maintaining an effective refrigerating operation as well as an effective cool storage operation. - Advantageously, the refrigerating system further comprises, in addition to the closed passageway, an additional passageway for connecting the recirculating passageway at a location between the compressor and the condenser with the recirculating passageway at a location between the first and second evaporators, and a switching means for obtaining switching between a first condition where the flow of the refrigerant along the closed passageway, i.e., the refrigerant from the compressor is passed through the condenser, the expansion valve and the first evaporator and is introduced into the second evaporator, and a second condition where the refrigerant from the compressor is passed through the additional passageway and is introduced into the second evaporator, i.e., by-passing the cool storage evaporator. The by-passing of the cool storage evaporator during the second condition can obtain a de-frosting operation, while preventing the cool storage material in the cool storage evaporator from melting.
- Advantageously, said temperature sensitive expansion valve comprises a first variable orifice in the recirculating passageway, a second variable orifice located downstream from the first orifice, and an actuator responsive to the temperature of the refrigerant at the outlet of the evaporators for controlling the first and second orifices in such a manner that, during the cool storage operation, an adiabatic expansion of the refrigerant occurs at the first orifice, while, during the refrigerating operation, an adiabatic expansion of the refrigerant occurs at the second orifice. During the refrigerating operation, a large amount of the recirculated refrigerant, suitable for the high load operation, is obtained, thereby maintaining a desired performance during a cool-down operation. During the cool storage operation (a low load operation), the second orifice can operate within a range where the degree of the superheating is controlled, thereby preventing hunting from occurring.
- Advantageously, the refrigerating system further comprises sensor means for detecting the temperature inside the chamber, and means for controlling the air flow generating means in such a manner that an increased amount of the air flow is obtained when the temperature inside the chamber is higher than a predetermined value during the refrigerating operation. As a result, an increase in the cooling capacity is obtained at the initial stage of the cool storage or refrigerating operation due to the fact the cool storage material is melted. In this case, an increase in the evaporating temperature at the refrigerating evaporator cause the melting of the cool storage material to be commenced at a region adjacent the cool storage evaporator. As a result, an effective use of the latent heat of melting of the cool storage material is realized.
- According to the present invention, a refrigerating system is provided, comprising:
a heat insulated chamber;
means for generating a flow of air recirculated in the chamber;
means arranged in the chamber for holding an amount of cool storage material, and;
a refrigerating recirculating unit including a compressor for compression of a refrigerant, a condenser for receiving the compressed refrigerant from the compressor, an expansion valve for reducing the pressure of the refrigerant from the condenser, a first evaporator for receiving the refrigerant at the reduced pressure for cooling the cool storage material, and a second evaporator for receiving the refrigerant of the reduced pressure for cooling the air flow recirculated in the chamber, a closed passageway for the refrigerant being constructed by the compressor, the condenser, the temperature sensitive expansion valve, the first evaporator and the second evaporator, said expansion valve being of a type capable of controlling the amount of the recirculated refrigerant in accordance with the temperature of the refrigerant at an outlet side of the second evaporator;
said cool storage evaporator comprising a plurality of packs, each of which includes a container for storing therein a cool storage material, and a tube of a serpentine arrangement which is located in the refrigerant recirculated passageway and which is in contact with the cool storage material. - Advantageously, said serpentine tube include portions projected out of and located below said packs. The projected portion functions as a heat pipe, thereby improving the cooling of the air inside the chamber.
- An embodiment of the present invention will be explained with reference to attached drawings in which:
- Fig. 1 is a schematic view of a refrigerating system according to the present invention.
- Fig. 2 is a perspective view of a refrigerated vehicle including the refrigerating system in Fig. 1.
- Fig. 3 is a perspective view of a cool storage evaporator in the refrigerating system in Fig. 1.
- Fig. 4 is a diagrammatic view of a control circuit in the refrigerating system in Fig. 1.
- Fig. 5 is a flow chart illustrating an operation of the control circuit in Fig. 4.
- Figs. 6A to 6E are timing charts illustrating an operation of the control circuit in Fig. 4.
- Fig. 7 is a plan view, partially exploded, of a cool storage evaporator in a second embodiment.
- Fig. 8 is a plan view, partially exploded, of a cool storage evaporator in a third embodiment.
- Fig. 9 is a cross sectional view of a temperature sensitive expansion valve in a fourth embodiment.
- Fig. 10 is similar to Fig. 9 but illustrating it under a low load (cool storage) operation.
- Fig. 11 shows the relationship between the degree of the opening of the expansion valve and a recirculated amount of the refrigerant.
- Fig. 12 is similar to Fig. 1 but illustrates a fifth embodiment.
- Fig. 13 is a cross sectional view of the electromagnetic valve in Fig. 12.
- Fig. 14 is a cross sectional view of a temperature sensitive expansion valve in a sixth embodiment.
- Fig. 15 is similar to Fig. 14 but shows it under a high load (refrigerating) operation.
- Fig. 16 is a cross sectional view of a refrigerated vehicle in a seventh embodiment.
- Fig. 17 is a partially enlarged view of a cool storage evaporator in Fig. 16.
- Fig. 18 is relationship between the time lapse after the start of a refrigerating operation and a inside temperature change in the seventh embodiment.
- Fig. 19 is a perspective view, partially exploded, of a cool storage evaporator in an eighth embodiment.
- Fig. 20 is a perspective view fully exploded of a cool storage evaporator in a ninth embodiment.
- Fig. 21 is a cross sectional view of the cool storage evaporator in a ninth embodiment.
- Fig. 22 is similar to Fig. 21 but illustrates it under a high load condition.
- Fig. 23 is a diagrammatic view of a control circuit in tenth embodiment.
- Fig. 24 is a flow chart illustrating an operation of the tenth embodiment.
- Fig. 25 shows, in tenth embodiment, Mollier diagrams at a refrigerating operation (a), a cool storage operation (b) and a cool down operation (c), respectively.
- A first embodiment of the present invention will be explained with reference to Figs. 1 to 6. Fig. 1 shows a construction of a refrigerating system for a refrigerated vehicle, while Fig. 2 shows the refrigerated vehicle to which the refrigerating system in Fig. 1 is attached. In Fig. 2, the
refrigerated vehicle 2 is provided with arefrigerating system 1. As shown in Fig. 1, the refrigeratingsystem 1 includes arefrigerating compartment 3, a refrigerating unit 4 with a cool storage device for cooling therefrigerating compartment 3, aninside blower 6 located inside therefrigerating compartment 3, and outsideblower 7 located outside therefrigerating compartment 3, and acontrol panel 8 in which control circuitry is housed for controlling the energization of the various parts of thesystem 1. - The
refrigerating compartment 3 is formed with a thermally insulated construction. Namely, therefrigerating compartment 3 is connected to a body of therefrigerated vehicle 2, and is formed as a box of a rectangular parallelepiped shape formed from a heat insulating material having a chamber therein for storing frozen or refrigerated foods. In a well known manner, therefrigerating compartment 3 is provided with a door 2-1 at the rear side thereof. - In Fig. 1, the refrigerating unit 4 for executing the refrigerating cycle includes a
refrigerant compressor 11, arefrigerant condenser 12, areceiver 12a, a temperature operatedautomatic valve 13, acool storage evaporator 14, a refrigeratingevaporator 15, anaccumulator 16 and a refrigerantflow switching valve 17. Furthermore, pipes are provided for connecting theses components with each other so that a refrigerating cycle is executed. Namely, thecompressor 11 has an outlet 11-1 connected to an inlet 12-1 of thecondenser 12. Thecondenser 12 has an outlet 12-2 connected to thereceiver 12a. Thereceiver 12a is connected, via the temperature operatedautomatic valve 13, to aninlet 26 of thecool storage evaporator 14. Thecool storage evaporator 14 has anoutlet 27 connected to an inlet 15-1 of the refrigeratingevaporator 15. The refrigeratingevaporator 15 has an outlet 15-2 connected, via theaccumulator 16, to an inlet 11-2 of thecompressor 11. - A
reference numeral 20 denotes an internal combustion engine of therefrigerated vehicle 2, and has a crankshaft 20-1, on which a pulley 20-2 is connected. Thecompressor 11 has a rotating shaft 11-3 and a pulley 11-4 on the shaft 11-3. Abelt 19 is provided for obtaining a kinematic connection between the pulleys 20-2 and 11-4. Furthermore, the pulley 11-4 is connected to a clutch 18 for selective transmission of a rotating movement of the pulley 11-4 to thecompressor 11. As a result, an engagement of the clutch 18 causes thecompressor 11 to be operated for executing a compression operation. As a result, the gaseous refrigerant sucked from the inlet 11-2 is subjected to a compression, and the compressed gas at a higher temperature and pressure is discharged from the outlet 11-1. In place of thecompressor 11 operated by theinternal combustion engine 20, an electrically operated compressor, the rotational speed of which is controlled by an inverter, can be employed. Furthermore, the compressor may be of a type of a variable outlet amount. - The
refrigerant condenser 12 is arranged at a desired location of therefrigerated vehicle 2, where an outside air flow, generated by the movement of the vehicle, is effectively contacted, i.e., at a bottom location of therefrigerating compartment 3 as shown in Fig. 2. At thecondenser 12, the gaseous refrigerant of high temperature and pressure from thecompressor 11 is subjected to a heat exchange with the outside air flow generated by theoutside blower 7 and the air flow generated by the movement of therefrigerated vehicle 2. As a result, the gaseous refrigerant is liquidized and is introduced into thereceiver 12a, where the liquid state refrigerant is separated. It should be noted that thereceiver 12a can be eliminated in case where a complete liquidation occurs at thecondenser 11. - The temperature-sensitive
automated valve 13 as an expansion valve is constructed by avalve member 21 as a throttle valve and atemperature sensing unit 22 for operating thevalve member 21. Namely, thevalve member 21 forms a throttled orifice (not shown) for ejecting the refrigerant from thecondenser 12, so that the refrigerant is subjected to an expansion, thereby obtaining a gas-liquid combined state of the refrigerant at a low temperature and pressure. - The temperature
sensitive unit 22 includes, in a well known manner, a temperaturesensitive tube 23, a operating member 24-1 such as a diaphragm actuator, and acapillary tube 24 having a first end opened to the space inside the temperaturesensitive tube 23 and a second end opened to the diaphragm 24-1. Inside the temperaturesensitive tube 23, a gas having the same components as the refrigerant is sealingly stored, so that the pressure of the gas in the temperaturesensitive tube 23 corresponds to a degree of a superheat of the gaseous refrigerant sucked into the compressor, which corresponds to the change in the temperature of the refrigerant at the outlet of the refrigeratingevaporator 15. The term "superheat" means an increase in a temperature (enthalpy) after a equibrium state is established during an evaporating phase in a refrigerating cycle. By way of thecapillary tube 24, the pressure in the temperaturesensitive tube 23 is opened to the diaphragm 24-1, so that thevalve 21 controls the degree of the throttle in accordance with the pressure change. Namely, in the operation of thetemperature sensing unit 22, an increase in the temperature of the refrigerant at the outlet of the refrigeratingevaporator 15 causes the gas in the pressure sensitive tube to expand, so that the operating unit 24-1 causes thevalve 21 to be moved in a direction to increase a flow area thereby increasing the amount of the recirculated refrigerant, which causes the temperature of the refrigerant to be decreased. Contrary to this, a decrease in the temperature of the refrigerant at the outlet of the refrigeratingevaporator 15 causes the gas in the pressure sensitive tube to be compressed, so that the operating unit 24-1 causes thevalve 21 to be moved in a direction to decrease a flow area, thereby reducing the amount of the recirculated refrigerant, which causes the temperature of the refrigerant to be increased. - Fig. 3 illustrates a construction of the
cool storage evaporator 14, which is located in therefrigerating compartment 3 at its top portion as shown in Fig. 2. As shown in Fig. 1, thecool storage evaporator 14 is, in the refrigerating circuit, located at a position upstream from the refrigeratingevaporator 15. In thecool storage evaporator 14, a heat exchange occurs between the gaseous-liquid combined state refrigerant and the cool storage material, so that the cool storage material is cooled, on one hand, and the refrigerant is evaporated to a gaseous state, on the other hand. In the first embodiment, thecool storage evaporator 14 is, as shown in Fig. 3, constructed by a plurality ofpacks 5 as a container made of a resin material of a good heat conductivity for filling therein a cool storage material, and atube 25 of a rounded cross sectional shape made from a metal material of a good heat conductivity. Thetube 25 has aninlet 26 for connection with the thermo-sensitive valve 13 for receiving the refrigerant therefrom, and anoutlet 27 for discharging the refrigerant to the refrigeratingevaporator 15. Therefrigerant tube 25 is formed as a serpentine shape which is constructed by a straight portions 25-1 spaced in parallel and curved portions 25-2 connecting the straight portions 25-1 with each other. Laterally two adjacent vertical rows of pairs ofpacks 5 are provided. In each pair, two adjacent straight portions are arranged between thepacks 5. The refrigerant from thecondenser 12 is passed through thetube 25, so as to cool the cool storage material. - In place of the
circular tube 25, a flattened refrigerant tube can be employed for increasing a heat exchanging surface area for increasing the refrigerating capacity. Furthermore, on the outer surface of thecircular tube 25, fins can be provided for increasing the heat exchanging capacity. - In the cool storage packs 5, a cool storage material is stored, such as a brine (a water solution of calcium chloride or sodium chloride et al.), or methanol water brine. In the illustrated embodiment, a cool storage material is used, which has a soldifing temperature or a melting temperature of, for example, -25°C, which is similar to the evaporating temperature of the refrigerant of, for example, -25°C of the refrigerating
evaporator 15, when the temperature of therefrigerating compartment 2 is reached to a first predetermined temperature of, for example, -20°C. - When the refrigerating system 4 is out of operation, i.e., the clutch 18 in the pulley 11-4 is de-energized for disconnecting the
compressor 11 from the rotating movement of the engine crankshaft 20-1, the cool storage material is melted, thereby maintaining a low temperature of the chamber inside therefrigerating compartment 3. In other words, latent heat, which is adsorbed when the cool storage material is melted, deprives heat from therefrigerating compartment 3, thereby maintaining a cooled condition of the refrigerating compartment. In the illustrated embodiment, the soldifing or melting temperature of the cool storage material is -25°C. However, an adjustment of the soldifing or melting temperature of the cool storage material is possible by varying the amount of the solute such as salt in a solvent such as a water of a fixed amount, or a set temperature at therefrigerating compartment 3. - The refrigerating
evaporator 15 is arranged in a duct of acooling unit 28 arranged at a top side of therefrigerating compartment 3, and is, in a well known manner, constructed as a stacked type heat exchanging device which is constructed by a pair of spaced tanks, a stack of heat exchanging tubes extending between the tanks and fins on the outer surfaces of the heat exchanging tubes. In the refrigeratingevaporator 15, a heat exchange occurs between an inflow of refrigerant from the cool storage evaporator and a flow of an inner air generated by theinner blower 6, so that the refrigerant is evaporated. - The
accumulator 16 is for separating the refrigerant from the refrigeratingevaporator 15 into a liquid phase and a gaseous phase, and for discharging only the gaseous phase refrigerant into thecompressor 11. - As shown in Fig. 1, the
flow switching valve 17 as an electromagnetic valve is arranged on a hot by-pass passageway 30 having one end connected to a recirculating pipe between the outlet 11-1 of thecompressor 11 and the inlet 12-1 of thecondenser 12. Theflow switching valve 17 is switched between a closed position where a normal flow of the refrigerant is obtained via thecondenser 12, thereceiver 12a, arecirculation pipe 29, thecool storage evaporator 14 and acheck valve 29a, and an opened position where a by-passed flow of the refrigerant is obtained via the by-pass passageway 30. Namely, when the switchingvalve 17 is in the closed position, thepassageway 29 allows the refrigerant to pass through thecondenser 12, thereceiver 12a as shown by an arrow a, theexpansion valve 13, and thecool storage evaporator 14. When the switchingvalve 17 is in the opened position, thepassageway 30 allows the refrigerant to be directly introduce into the refrigeratingevaporator 15, as shown by an arrow b, i.e. to by-pass thecondenser 12, thereceiver 12a, theexpansion valve 13, and thecool storage evaporator 14, thereby executing a defrosting operation. In the by-pass condition, thecheck valve 29a prevents the refrigerant from being reversed. - The
inner blower 6 is constructed by ainner fan 31 for generating an air flow in the duct of the coolingunit 28 and anelectric motor 32 for generating a rotating movement applied to theinner fan 31. In a well known manner, a bearing means is provided for rotatably connecting thefan 31 to the duct of the coolingunit 28. Thefan 31, when the rotating movement from theelectric motor 32 is applied, sucks the inner air in therefrigerating compartment 3 into the duct of the coolingunit 28 as shown by an arrow f1, so that the air flow is directed to the refrigeratingevaporator 15 arranged in the duct. As a result, a heat exchange is occurred at theevaporator 15 between the refrigerant and the air flow, which causes the air flow is cooled. The thus cooled air is, after contacting thecool storage evaporator 14, discharged to the space inside therefrigerating compartment 3, as shown by an arrow f2. As shown in Fig. 2, acontrol panel 8 is arranged inside therefrigerating compartment 3 for controlling the operation of theinner fan motor 32. In a well known manner, theelectric motor 32 can be provided with a means for obtaining two or more steps of control, or a stepless control, of themotor 32. - The
outside blower 7 is, as shown in Fig. 1, constructed by anouter fan 33 for generating an outside air flow contacting with therefrigerant condenser 12 and anouter fan motor 34 for generating a rotating movement applied to theouter fan 33. Theouter fan 33 is located adjacent to thecondenser 12. Theouter fan motor 34 is also controlled by thecontrol panel 8, so that thefan motor 34 is selectively operated. It is also possible to construct thecontrol panel 8 such that two or more steps of control, or a stepless control, of themotor 32 is obtained in order to adjust the amount of the air flow generated by theoutside fan 33. - Fig. 4 shows, schematically, a construction of the control panel which is constructed as a microcomputer system including, in a well known manner, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM) and a timer circuit (clock signal generator). In a well known manner, various switches, setters and sensors are connected to the
control panel 8, such as a switch 8-1 for making the refrigerating system operate, a switch 8-2 for obtaining a desired setting of a temperature inside therefrigerating compartment 3, a de-frosting switch 8-3, asensor 37 for detecting an actual temperature inside therefrigerating compartment 3, and a sensor for detecting a temperature of the cool storage material. - Relay coils 39 to 42 are also connected to the
control panel 8. Therelay coil 39 has acontact 43 for controlling an on-off operation of the clutch 18. Therelay coil 40 has acontact 44 for controlling an on-off operation of the refrigerantflow switching valve 17. Therelay coil 41 has acontact 45 for controlling an on-off operation of theinner fan motor 32. Therelay coil 42 has acontact 46 for controlling an on-off operation of theouter fan motor 34. Thecontrol panel 8 responds to signals from the operating switch 8-1, the inner temperature set switch 8-2, the de-frosting switch 8-3, theinner temperature sensor 37 and the cool storagematerial temperature censor 38 so that the relay coils 39 to 42 are selectively energized in such a manner that a desired manner of operations of the clutch 18, the refrigerantflow switching valve 17, theinner fan motor 32 and theouter fan motor 34 is obtained, as will be fully described later. - Namely, the operation switch 8-1 commences a refrigerating operation as well as a cool storage operation of the refrigerating system 4. When the operating switch 8-1 is made ON, a signal is issued to obtain the refrigerating operation and the cool storage operation, which are alternately executed.
- The set switch 8-2 can set a temperature inside the refrigerating compartment to a desired temperature of, for example, -18°C.
- The defrost switch 8-3 initiates a defrosting operation, where the refrigerant flow
direction switching valve 17 is made ON for a predetermined duration of time, such as one hour, thereby defrosting the refrigeratingevaporator 15. - The
inner temperature sensor 37 is constructed as a thermistor or thermostat and is arranged at a suitable location inside therefrigerating compartment 3 to detect the inside temperature. Thecontrol panel 8 is programmed such that, when the temperature Ta inside therefrigerating compartment 3, as detected by thesensor 37, is reduced to a value which is lower than a first predetermined value T1, which corresponds to the set temperature Ts minus a predetermined temperature reduction ΔT (°C) and is, for example, a value of -20°C, theinside fan motor 32 is made OFF, which allows a cool storage operation to be commenced. When the temperature Ta inside therefrigerating compartment 3 as detected by thesensor 37, is increased to a second predetermined value T2, which corresponds to the set temperature Ts plus a predetermined temperature increase ΔT (°C) and is of, for example, a value of -16°C, theinside fan motor 32 is made ON, which allows a refrigerating operation to be commenced. - The cool storage
material temperature sensor 38 is constructed, for example, as a thermistor or thermostat, and is arranged on a surface of thecool storage pack 5 such that the temperature Tb of the cool storage material is detected by thesensor 38. Thecontrol panel 8 is programmed such that, when the temperature Tb of the cool storage material detected by thesensor 38 is reduced to a temperature lower than a setting temperature Tg of the cool storage material, i.e., when temperature Tb is reduced to the setting temperature Tg minus a predetermined value ΔT (°C) (for example 25°C - 2°C), the clutch 18 of therefrigerant compressor 11, theinside fan motor 32 and theoutside fan motor 34 are made OFF, thereby executing the cool keeping operation. - As explained above, the relay coils 39 to 42 selectively make on or off the relay switches 43 to 46 for selectively energizing the clutch 18 of the
refrigerant compressor 11, theinside fan motor 32 and theoutside fan motor 34, respectively. In place of such a relay circuit, a semi-conductor switching circuit using semi-conductors can be employed. - As mentioned above, the refrigerating system can take various modes of operation, including the cooling mode, the cool storage mode, the de-frosting mode, and the OFF mode (cool keeping mode) as selected by the
control panel 8. The following Table 1 shows, at these various modes, operating conditions of therefrigerant switching valve 17, the electromagnetic clutch 18, theinside fan motor 32 and theoutside fan motor 34.Table 1 Modes Switching Valve 17 Clutch 18Inner Fan Motor 32Outer fan Motor 34Refrigeration OFF (Close) ON ON ON Cool Storage OFF (Close) ON OFF ON Defrost ON (Open) ON OFF OFF Cool keeping OFF (Close) OFF OFF OFF - Now, an operation of a
control panel 8 of this embodiment will be explained with reference to Figs. 1 to 5. Fig. 5 is a flowchart illustrating a operation of thecontrol panel 8 for switching between the refrigerating operation and the cool storage operation. - When the operation switch 8-1 is made ON, the program begins execution. At step S1, a solidifying temperature Tg of the cool storage material minus a predetermined reduced value ΔT (°C) is calculated. At a following step S2, a set temperature Ts set by the inside temperature set switch 8-2 is read out. At step S3, the first predetermined value T1 = Ts (set temperature) - ΔT is calculated, and the second predetermined value
inner temperature sensor 37 and the cool storage material temperature Tb detected by thesensor 38 are read out. - At step S5, it is determined if the inside temperature Ta detected by the
inside temperature sensor 37 is lower than the first predetermined temperature T1 of, for example, -20°C. When a result of the determination at the step S5 is "No", i.e., the inside temperature Ta is higher than the first predetermined temperature T1, the routine goes to step S6, where it is determined if the inside temperature Ta detected by theinside temperature sensor 37 is higher than the second predetermined temperature T2 of, for example, -16°C. When a result of the determination at the step S6 is "Yes", i.e., the inside temperature Ta is higher than the second predetermined temperature T2, the routine goes to step S7, where the refrigerating operation is executed by making ON the clutch 18 of therefrigerant compressor 11, and the inside andoutside fan motors flow switching valve 17. The routine goes to step S2 for a repetition. - When a result of a determination is "Yes" at the step S5, i.e., the inside temperature Ta is lower than the first predetermined temperature T1 (Ta ≦ -20°C), or a result of a determination is "No" at the step S6, i.e., the inside temperature Ta is lower than the second predetermined temperature T2 and higher than the first predetermined value (-20°C < Ta < -16°C), the routine goes to step S8, where it is determined if the temperature of the cool storage material Tb detected by the
sensor 38 is lower that the setting temperature Tg (-25°C) minus ΔT (-2°C). When a result of "No" is obtained at the step S8 (Tb > -27°C), the routine goes to step S9, where the cool storage operation executed by making ON the clutch 18 of therefrigerant compressor 11 and theoutside fan motor 34 and by making OFF the refrigerantflow switching valve 17 and theinside fan motor 32. The routine goes to step S2 for a repetition. - When a result of a determination is "Yes" at the step S8 (Tb ≦ -27°C), the routine goes to step S10, where the cool keeping operation executed by making OFF the clutch 18 of the
refrigerant compressor 11, the inside andoutside fan motors flow switching valve 17. It should be noted that the "No" determination at step S6 (-20°C < Ta < -16°C) can cause the routine goes to step S9 without executing the step S8. - Now, an operation of the
refrigerating system 1 for a refrigerated vehicle will be explained with reference to Figs. 1 to 4 and 6A to 6E. Figs. 6A to 6E illustrate timing charts illustrating an inside temperature, an evaporating temperature, an operating condition of the inside fan, an operating mode of the apparatus and an operating condition of the electromagnetic clutch, respectively. At time t0, the operating switch is made ON, which causes thecompressor 11, theinside fan 31 and theoutside fan 33 to be brought into operation. The refrigerant flowdirection switching valve 17 is maintained in its OFF condition, so that a flow of the refrigerant by way of the first refrigeratingpassageway 29 is obtained. As a result, the gaseous state refrigerant of a high temperature and pressure from thecompressor 11 is introduced into thecondenser 12, where the refrigerant is liquidized, and into thereceiver 12a where separation occurs between the gaseous and liquid phases. Only the liquid state refrigerant is introduced into temperature operatedautomatic valve 13, where the liquid state refrigerant is subjected to a rapid expansion, so that the refrigerant is changed to a mist state (gas and liquid combined state) at a low temperature and pressure. The mist state refrigerant is introduced into thecircular tube 25 of thecool storage evaporator 14, so that a heat exchange occurs between the refrigerant and the cool storage material in the cool storage packs 5, so that the refrigerant is evaporated, so as to obtain a gas and liquid combined state, where the amount of the gaseous component is larger than the amount of the liquid component. The combined state refrigerant is introduced into the refrigeratingevaporator 15. The heat exchange of the refrigerant with the cool storage material causes the temperature of the cool storage material in thecool packs 5 to be reduced due to the evaporation heat of the refrigerant at thecool storage evaporator 14. The gas and liquid combined states of refrigerant is, then, introduced into the refrigeratingevaporator 15, so that a heat exchange with the refrigerant occurs with respect to the inside air flow generated by theinside fan 31, so that the refrigerant is evaporated and is introduced into theaccumulator 16. At theaccumulator 16, the gaseous state refrigerant is separated from the liquid state refrigerant and is introduced into thecompressor 11, thereby repeating the refrigerating cycle. - During the execution of the refrigerating cycle, the air, cooled at the refrigerating
evaporator 15 by means of the evaporating heat of the refrigerant, is discharged from the duct 28-1 of the cooling device into the space inside therefrigerating compartment 3. As a result of a continuation of such a cooling operation of the refrigerating compartment, the evaporating temperature of the refrigerant at thecool storage evaporator 14 as well as the refrigeratingevaporator 15 is reduced as shown in a line m in Fig. 6B. As a result, the temperature inside therefrigerating compartment 3 is also reduced as shown by a line n in Fig. 6A. - When the inside temperature Ta is reduced to the first predetermined temperature T1 (-20°C) at a timing t1, the
control panel 8 causes theinside fan motor 32 to be made OFF, which prevents theinside fan 31 to be rotated, while maintaining theoutside fan 33 as well as the elector-magnetic clutch 18 to be operated, so that the refrigerating cycle is continued, thereby executing the cool storage operation. In this cool storage operation, an air flow contacting with the refrigeratingevaporator 15 is stopped, thereby reducing the heat exchange capacity at theevaporator 15. In other words, the refrigeratingevaporator 15 does not substantially act to evaporate the refrigerant. As a result, the temperature of the gaseous refrigerant at the refrigeratingevaporator 15 is reduced. Thus the pressure at the temperaturesensitive tube 23 opened to the diaphragm actuator 24-1 via theconduit 24 causes the degree of the throttle of thevalve member 21 of theexpansion valve 21 to be reduced, thereby reducing the amount of the refrigerant introduced into thecool storage evaporator 14. - It should be noted that the evaporating temperature of the refrigerant recirculating in the refrigerating circuit 4, i.e., the temperature of the refrigerant evaporated at the
cool storage evaporator 14 is determined when a capacity Qa at the air side and a capacity QR at the refrigerant side are balanced, which are expressed by the following equations, that areinside fan 31,
φ is a value determined in accordance with shapes of thecool storage evaporator 14 and the refrigeratingevaporator 15 such as a heat transfer area or heat transfer coefficient, and
Δi is a difference in enthalpy in kcal/kg between the inlet side of thecool storage refrigerant 14 and the outlet of the refrigeratingevaporator 15. - As a result, the evaporating temperature of the refrigerant at the
cool storage evaporator 14 is, from the first evaporating temperature Te1 (-25°C) at the timing t1 when theinside fan motor 32 is made off, further reduced to a second evaporating temperature Te2 (-35°C), as shown by a curve o in Fig. 6B. As a result, in thecool storage evaporator 14, the cool storage material in the cool storage packs 5 covering thecircular tube 25 is further cooled, thereby executing cool storage operation. During the execution of the cool storage operation, the inside temperature is increased as shown by a curve p in Fig. 6A. - At a timing t2, the inside temperature Ta in the
refrigerating compartment 3 is increased to the second predetermined value T2 (-16°C), theinside fan motor 32 is again made ON, so that theinside fan 31 generates a flow of the air inside therefrigerating compartment 3 induced by the convection thereby commencing the refrigerating operation. - The repetition between the refrigerating operation and the cool storage operation, taken place alternately, causes the temperature Tb of the cool storage material in the cool storage packs to be lower than the setting temperature Tg (-25°C) minus a predetermined value ΔT (-2°C), by which it is judged that the freezing of the cool storage material is completed. In this case, a refrigerating operation by making ON the electro-
magnetic clutch 18 and a rest (cool keeping) operation by making OFF the clutch 18 are repeated for controlling the temperature of the refrigerating compartment. Namely, the refrigerating operation is continued to a time t₄, where the temperature of the refrigerant is reduced to a first temperature T₁ Then the clutch 18 and thefan motor 32 are made OFF, so as to commence the cool keeping operation. Namely, the latent heat of the cool storage material in the packs 4, when it is molten, can prevent the inside temperature form being quickly increased. - A stoppage of the operation of the
internal combustion engine 20 causes the refrigerating unit 4 to be de-energized, which causes the inside temperature of therefrigerating compartment 3 to be increase, thereby the cool storage material to be molten. The melting latent heat of the cool storage material in the cool storage packs 5 causes the cool keeping operation of the refrigerating compartment to be executed. - By the
control panel 8, the refrigerantflow switching valve 17 is made ON, when the defroster switch is made ON by an operator or, during the refrigerating or the cool storage operation of the refrigerating operation, a predetermined condition is detected such that a predetermined value of the evaporating pressure or the temperature of the refrigeratingevaporator 15 is detected or a predetermined duration of, for example, 1 hour of the refrigerating or cool storage operation is obtained. Such a switching on of thevalve 17 causes the flow of the refrigerant to be switched from the first refrigeratingpassageway 29 to the secondrefrigerant flow passageway 30 as shown by the arrow b in Fig. 1. As a result, the defrosting operation is commenced. Namely, the refrigerant of a high temperature or high pressure is directly introduced into therefrigerant evaporator 15 via the second refrigeratingpassageway 30. As a result, the surface of therefrigerant evaporator 15 is defrosted or de-iced. - As explained above, in the first embodiment, the
cool storage evaporator 14 and the refrigeratingevaporator 15 are connected in series, and the temperaturesensitive expansion valve 13 is for controlling the degree of the throttle in accordance with the change in the temperature at the cutlet of the refrigeratingevaporator 15. Furthermore, the melting temperature of the cool storage material in the cool storage packs 5 of thecool storage evaporator 14 is determined so that it is the same degree as the evaporating temperature, for example -25°C, of the refrigerant in the refrigeratingevaporator 15 when the temperature inside therefrigerating compartment 3 is reached to the first predetermined value. A cooling of the cool storage material having such a value of the melting temperature by thecool storage evaporator 14 prevents the cool storage material in thecool storage evaporator 14 from being frozen, thereby preventing the cool storage material from being over-loaded. Furthermore, in the cool storage operation, the throttling operation of the temperaturesensitive expansion valve 13 can maintain a suitable difference between the temperature of the cool storage material and the evaporating temperature of the refrigerant in thecool storage evaporator 14. As a result, in the refrigerating system for the refrigerated vehicle, the refrigerating operation and the cool storage operation, which take place alternately, can be executed efficiently. - Furthermore, in the first embodiment, downstream from the
cool storage evaporator 14, the refrigeratingevaporator 15 is connected in series, and the secondrefrigerant passageway 30 connects the outlet 11-1 of thecompressor 11 directly with the inlet of the refrigeratingevaporator 15. As a result, during the defrost operation of the refrigerating unit 4 i.e., when the refrigeratingevaporator 15 is defrosted, the gaseous refrigerant of a high temperature and pressure from the outlet of thecompressor 11 is introduced into the refrigeratingevaporator 15 while by-passing thecondenser 12, theexpansion valve 13 and the cool storage evaporator. As a result, the cool storage material in the cool storage packs 5 of thecool storage evaporator 14 is prevented from being melted. - In short, in the
refrigerating system 1 in the first embodiment of the present invention as explained above, only one refrigerant flowdirection switching valve 17 is sufficient for obtaining an effective refrigerating operation with a cool storage function, thereby reducing the number of parts as well as the production cost. - Fig. 7 shows a second embodiment of the
cool storage evaporator 14 of the refrigerating system for a refrigerated vehicle. Thecool storage evaporator 14 includes acontainer 52 and a serpentine arrangement of therefrigerant pipe 53. Thecontainer 52 stores thecool storage material 51 with which therefrigerant pipe 53 is contacted. This construction is advantageous in that the weight of the device is reduced. Furthermore, therefrigerant pipe 53 is, on its outer surface, formed withfins 54 of a spiral fin structure or plate fin structure for increasing a heat exchanging capacity. The refrigeratingpipe 53 has afirst end 55 for receiving the refrigerant from theexpansion valve 13 and asecond end 56 for discharging the refrigerant into the refrigeratingevaporator 15. - In a third embodiment shown in Fig. 8, the cool storage evaporator of a refrigerating system for a refrigerated vehicle includes a
container 52 similar to as that in the second embodiment in Fig. 7, in whichcontainer 52capsules 57 made of resin or metal material for sealingly storing therein the cool storage material are filled. - A fourth embodiment will now be explained. Fig. 9 shows a construction of the temperature
sensitive expansion valve 13 in this embodiment. Namely, as in to the first embodiment, the temperature operatedautomatic expansion valve 13 includes avalve casing 21, a temperaturesensitive unit 22, which is constructed by a thermo-sensitive tube 23 and acapillary tube 24, avalve rod 71, a first and second ball shapedvalves valve rod 71 and arranged movably in thevalve casing 21 so as to createvariable throttles diaphragm mechanism 67 for generating a pressure force in thevalve rod 71, acoil spring 63 for urging thevalve rod 71 toward thediaphragm mechanism 67, aspring seat 73, which receives at its first end the second ball shapedvalve 62 and is connected at its second end to the upper end of the spring, and an adjustingscrew 74 to which the lower end of thespring 63 rests. - The
valve casing 21 is formed from a metal material such as brass and is formed therein with apassageway 64 of a generally L-shape and for a refrigerant. The L-shapedpassageway 64 has an upstream end connected to an outlet to thecondenser 12 for receiving the liquid state refrigerant as shown by an arrow r and a downstream end connected an inlet of thecool storage evaporator 14 for discharging the refrigerant thereto as shown by an arrow s. In Fig. 9, the first andsecond orifices refrigerant passageway 64. Thefirst orifice 65 on the upstream side has an inner diameter which is larger than that of thesecond orifice 66 on the downstream side. Furthermore, the inner diameters of the first andsecond orifices second balls orifices orifices - The
diaphragm actuator 67 is constructed by a lower diaphragm cover 67-1 connected to avalve casing 21, an upper diaphragm cover 67-2 connected to the lower diaphragm cover 67-1, adiaphragm 70 between the upper and lower diaphragm covers 67-1 and 67-2, and adiaphragm stopper 72 concentrically connected to therod 71. Anupper diaphragm chamber 68 is formed on an upper side of thediaphragm 70, while alower diaphragm chamber 69 is formed on a lower side of thediaphragm 70. Theupper diaphragm chamber 68 is connected to thecapillary tube 24. Thecasing 21 is formed with anopening 21a having a first end opened to thelower chamber 69 and a second end connected to apressure equalization conduit 60, which is connected to a refrigerating pipe in Fig. 1 at a location between the temperature operatedautomatic valve 13 and thecool storage evaporator 14, so that the pressure in thelower chamber 69 corresponds to a lower pressure, i.e., an evaporating pressure in the refrigerating recirculation system. - Inside the temperature
sensitive tube 23, an amount of a gaseous refrigerant, which is the same refrigerant as that recirculated in the refrigerating system, is sealingly stored. Furthermore, as explained with reference to Fig. 1, the temperaturesensitive tube 23 is arranged to be in side by side contact with the refrigerant tube at the outlet of therefrigerant evaporator 15. As a result, a pressure inside the temperaturesensitive tube 23, i.e., the pressure in theupper chamber 68 is varied in accordance with the temperature of the refrigerant flowing in the refrigerating recirculation system. - In view of the above, a pressure corresponding to the pressure at the thermo-sensitive tube is generated in the
upper chamber 68, which causes thediaphragm 70 to be moved downwardly. Furthermore, a pressure corresponding to the lower pressure in the refrigerating system is generated at thelower diaphragm chamber 69, which causes thediaphragm 70 to be moved upwardly. Furthermore, thespring 63 generates a force for moving thediaphragm 70 upwardly. As a result, the ball shapedvalves shaft 71 connected to thediaphragm 70 are located at respective positions, which are determined by a balance between the downwardly directed force by the pressure at theupper chamber 68 and the upwardly directed forces by the pressure at thelower chamber 69 and by thespring 63, and which determine the degrees of the throttle at theorifices screw 74 causes the latter to be moved axially, thereby varying the spring force of thespring 63, i.e., the pressure for making thesecond ball valve 62 open. - Now, an operation of the fourth embodiment in Figs. 9 to 11 will be explained. A refrigerating operation for reducing the inside temperature of the refrigerating compartment causes the refrigerating load to be increased, thereby increasing the temperature of the gaseous refrigerant at the outlet of the
refrigerant evaporator 15. As a result, the gaseous refrigerant in the temperaturesensitive tube 23 is subjected to expansion, so that the pressure at theupper diaphragm chamber 68 is higher than the pressure at thelower diaphragm chamber 69, which causes the operatingrod 71 to be moved downwardly. As a result, thefirst ball valve 61 takes a first position as shown in Fig. 1, where thefirst ball valve 61 is downwardly spaced from thefirst orifice 65. In this first position, the degree of the throttle of the first orifice is small, which prevents the refrigerant passing through theorifice 65 from being subjected to an adiabatic expansion. As a result, the liquid state refrigerant introduced into therefrigerant passageway 64 as shown by the arrow r from the condenser is passed through thefirst orifice 65 as shown by an arrow t without being subjected to the adiabatic expansion, and is introduced into thesecond orifice 66 in the liquid state. In this case, the second ball shapedvalve 62 is, as shown in Fig. 9, at a position, where thesecond valve 62 is spaced from thesecond orifice 66, so that a small degree of the throttle of thesecond orifice 66 is obtained, thereby obtaining a large amount of the recirculate amount of the refrigerant passing through thesecond orifice 66 as shown by an arrow u. The refrigerant is, when passing through thesecond orifice 66 as shown by the arrow u, subjected to the adiabatic expansion due to the small inner diameter of theorifice 66. The adiabatic expansion occurred when the refrigerant passes through thesecond orifice 66 as shown by the arrow u causes the refrigerant to be expanded, thereby obtaining a gas/liquid combined state refrigerant at a low temperature and pressure. Such a gas/liquid combined state refrigerant issues from theexpansion valve assembly 13 as shown by the arrow s in Fig. 9, and is introduced into the tube 25 (Fig. 3) of the rounded cross-sectional shape of the cool storage packs 5. As a result, a heat exchange is occurred between the refrigerant and the cool storage material in thepacks 5, so that the refrigerant is evaporated and so that the gas/liquid combined state refrigerant of an increased amount of gaseous state is obtained and is introduced into therefrigerant evaporator 15. The evaporating heat of the refrigerant at thecool storage evaporator 14 causes the cool storage material in the cool storage packs 5 to be subjected to temperature reduction. On the other hand, the mist state refrigerant flowing into therefrigerant evaporator 15 is subjected to heat exchange with the inside air flow generated by theinside fan 31 as rotated by theelectric motor 32, so that the refrigerant is evaporated under a super heated condition at the outlet of therefrigerant evaporator 15. Finally, the degree of opening of thesecond orifice 66 is such that a large amount of the refrigerant passing through theorifice 66 suitable for the high load operation is obtained, which allows the inside air in therefrigerating compartment 3 to be effectively cooled, thereby reducing the inside temperature of the refrigerating compartment. - A cool storage operation is obtained by making OFF the
inside fan motor 32, while maintaining the ON conditions of the electromagnetic clutch 18 as well as theoutside fan motor 34. The stoppage of theinside fan 31 in this cool storage operation causes the heat exchange to be reduced between the refrigerant in therefrigerant evaporator 15 and the inside air in the refrigerating compartment, thereby substantially preventing the refrigerant from being evaporated. The reduction of the refrigerating load in therefrigerating compartment 3 causes the temperature of the refrigerant to be reduced at the outlet of therefrigerant evaporator 15, which causes the gas in the temperature sensitive tube to be compacted. As a result, the pressure at theupper diaphragm chamber 68 is reduced toward the pressure at thelower diaphragm chamber 69, so that thediaphragm 70, i.e., the operatingrod 71 is moved upwardly to a position as shown in Fig. 10. In this case, the first ball shapedvalve 61 is located to be vertically aligned with thefirst orifice 65, while the second ball shapedball valve 62 is located vertically aligned with thesecond orifice 66. The throttling operation by means of the second ball shapedvalve 62 causes the evaporating pressure to be reduced in the refrigerant recirculating system, on one hand, and the recirculated amount of the refrigerant to be reduced, on the other hand. As a result, the refrigerant passed through thefirst orifice 65 is subjected to an adiabatic expansion, thereby causing the refrigerant to be in a gas/liquid combined state. In other words, the state of the refrigerant introduced into thesecond orifice 66 is under the gas/liquid combined state rather than the liquid state. Due to the combined state of the refrigerant at thesecond orifice 66, the flow area is increased while maintaining the same amount of the recirculated refrigerant. Thus, thesecond ball valve 62 can be operated in a range for controlling the degree of the superheating of the refrigerant. - In Fig. 11, the temperature operated expansion valve of a conventional structure employed in the first embodiment in Fig. 1 has a structure as shown in a block b, where only a signal orifice a is provided. Contrary to this, the evaporating temperature is different between the
cool storage evaporator 14 and therefrigerant evaporator 15. In this case, the volume as well as the opening pressure of the conventional temperature sensitive valve can be set for the higher evaporating temperature at therefrigerant evaporator 15. In this case, switching to the cool storage operation due to a reduced load causes the temperature sensitive valve to throttle the orifice, so as to make the system to respond to a small necessary amount of the recirculated refrigerant. However, such a reduction of the recirculated refrigerant occurs very rapidly as shown by a dotted curve x in Fig. 11, thereby causing the valve to be out of a control range, thereby generating hunting as large as H₁ for a fixed valve lift y. Contrary to this, a setting of the volume as well as the opening pressure of the conventional temperature sensitive valve suitable for the lower evaporating temperature at thecool storage evaporator 14 causes the recirculating amount of the refrigerant to be reduced, which causes the cooling capacity of the system to be reduced. In short, a single orifice structure b is disadvantageous in that a requirement for stable control during a low load condition (cool storage operation) and a desired cooling capacity during a high load condition can not be harmonized. - In the fourth embodiment of the present invention, the first and
second orifices valves second orifice 62 functions to vaporize the refrigerant, which is effective for preventing the cooling down capacity from being reduced. During the cool storage operation where the lift of the valve is small, thefirst orifice 65 functions to vaporize the refrigerant, downstream of which thesecond orifice 66 as well as thesecond valve 62 are located as shown by ablock 13 in Fig. 11. Since the refrigerant at thesecond orifice 66 is under a liquid/gas combined state unlike the liquid state at the second orifice during the high load mode, thesecond ball valve 62 can obtain a gradual reduction of the recirculated amount with respect to a change in the degree of the throttle as shown by x' in the solid curve in Fig. 11. In other words, thesecond valve 66 is moved in a range wherein a degree of superheat of the refrigerant is controlled, thereby reducing the amount of hunting to as small as H₂ for the same fixed valve lift y. - Now, a fifth embodiment of the present invention will be explained with reference to Figs. 12 and 13. In Fig. 12, showing a refrigerant recirculating system, wherein a temperature operated
automatic expansion valve 13, of a usual type including, therein, a second throttle portion, and anelectromagnetic valve 76 are arranged on the refrigerant tube at a location between the outlet of thecondenser 12 and the inlet of the temperature operatedexpansion valve 13. As shown in Fig. 13, theelectromagnetic valve 76 includes ahousing 78 havingrefrigerant passageways 77 and 77-1, avalve opening 79 between thepassageways 77 and 77-1 and by-pass port 75 by-passing thevalve port 79, theelectromagnetic valve 76 further includes aneedle valve 80 for selectively opening or closing thevalve port 79, avalve seat 84 and aelectromagnetic actuator 81 for operating theneedle valve 80. Theelectromagnetic actuator 81 is constructed by a plunger 81-1 connected to theneedle valve 80, aspring 83 for generating a spring force for causing theneedle valve 80 to be seated on thevalve seat 84 and aelectromagnetic coil 82 for generating an electromagnetic force for causing the plunger 81-1 to be moved against the force of thespring 83. - In this fifth embodiment, the
electromagnetic coil 82 is, under the low load condition such as a cool storage operation, de-energized, so that theneedle valve 80 shuts off thevalve port 79. As a result, the flow of the refrigerant from thecondenser 12 to theexpansion valve 13 is occurred by way of the by-pass port 75. The refrigerant passing through the by-pass port 75 of a reduced dimension is subjected to an adiabatic expansion so that a gas/liquid combined state of the refrigerant is obtained. Contrary to this, during a high load operation including a refrigerating operation, theelectromagnetic coil 82 is energized, so that the plunger 81-1 connected to theneedle valve 80 is moved upwardly against the spring force of thespring 83. As a result, the refrigerant passes thevalve port 79 of an increased dimension while maintaining the liquid state, thereby increasing a recirculated amount of the refrigerant. Namely, the fifth embodiment operates in the same way as the fourth embodiment in that recirculated amount of the refrigerant is controlled in accordance with the refrigerating load. - Now, a temperature operated expansion valve in sixth embodiment will be explained with reference to Figs. 14 and 15. In Fig. 14, the temperature operated
expansion valve 13 includes adisk 85 as a first valve and aball 62 as a second valve. Afirst seat plate 87 includes acentral opening 88 through which thevalve shaft 71 passes, and a plurality of circumferentially spacedorifices 65. Anotherseat plate 86 is located downstream from thefirst plate 87 and is formed with anorifice 66. Avalve 85 of a disk shape faced with theopening 88 is fixedly connected to theshaft 71. Avalve 62 of a ball shape faced with theorifice 66 is fixedly connected to thevalve shaft 71. Thecentral communication opening 88 has an effective opening area larger than that of thesecond orifice 66. Furthermore, thefirst orifice 65 in theplate 87 has an effective area which is smaller than the effective area of thesecond orifice 66. AS a result, when the refrigerant passes through thefirst orifice 65, an adiabatic expansion occurs in the refrigerant. - During the operation of the temperature operated expansion valve of the sixth embodiment as explained above, a low load operation caused by the cool storage operation causes the
diaphragm 70 to be moved upwardly to take a position as shown in Fig. 14, where the plate shaped valve closes thecentral opening 88, so that the refrigerant from the condenser introduced into thepassageway 64 is passed through thefirst orifices 65, whereat the refrigerant is subjected to adiabatic expansion, thereby obtaining a gas/liquid combined state refrigerant, which is introduced into thesecond orifice 66. Thus, in this low load condition, thesecond valve 62 of the ball shape controls the flow of the gas/liquid combined state refrigerant from thefirst orifice 65. Contrary to this, a high load operation caused by the refrigerating operation causes thediaphragm 70 to be moved downwardly to take a position as shown in Fig. 15, where the plate shapedvalve 85 is displaced from theseat plate 87, thereby opening thecentral opening 88, so that an increased amount of the refrigerant from thecondenser 12 introduced into thepassageway 64 is passed through thecentral opening 88 of an increased dimension while maintaining a liquid state condition. Namely, a similar operation as that in the fourth embodiment in Figs. 9 to 11 is obtained. - As seventh embodiment will now be explained with reference to Figs. 16 to 18. Fig. 16 shows a refrigerated vehicle provided with a refrigerating system includinq a
cool storage evaporator 14. Thecool storage evaporator 14 is arranged on an upper part of therefrigerating compartment 3, and is constructed by cool storage packs 5 formed as containers for storing a cool storage material made of a resin of an increased heat conductivity and by aserpentine tube 90 of a circular cross sectional shape of an outer diameter of 15.8 mm. Theserpentine tube 90 extends in a vertical plane and is constructed by straight pipe portions and U-shaped connecting portions, which are arranged alternately. Opposite pairs of the cool storage packs 5 are provided, between which the straight portions of theserpentine tube 90 are sandwiched, so that the straight and U-shaped portions are partly downwardly projected out of the cool storage packs 5. The straight portions and the U-shaped portions, which are not sandwiched by the cool storage packs 5, construct a heat absorber 91 (lower section), while the straight portions, which are sandwiched by the cool storage packs, construct a heat emitter section 92 (upper section). A value of length L of theheat absorbing section 91 from the bottom end of the cool storage packs 5 is in a range between 0.6m to 0.7m. The circular crosssectional tube 90 has aninlet 93 for the introduction of the refrigerant and anoutlet 94 for the discharge of the refrigerant. Theheat absorber 91 of the roundedtube 90 may be the type with fins so as to increase a heat exchanging capacity. Finally, theheat absorber 91 of the rounded tube may be the one with spine fins so as to increase a heat conduction area, thereby improving a cool keeping capacity. - Now, an operation of the seventh embodiment will be explained with reference to Figs. 16 to 18. A cool keeping operation is executed, when it is required that a low temperature is maintained inside the
refrigerating compartment 3, while the engine is stopped. Such a cool keeping operation is desirable when an emission of an exhaust gas from the engine is not allowed or a reduction of a noise is required. Fig. 17 illustrates a condition of the refrigerant in the rounded tube under the a cool keeping operation. Namely, at theheat absorber 91 located outside the cool storage packs 5, heat from a low temperature inside air at, for example, -10°C is absorbed by the liquid state refrigerant in the bottom of thetube 90, thereby gasifying the refrigerant. The gasified refrigerant is moved upwardly toward theheat emitter 92 as shown by arrows w. At theheat emitter 92, thetube 90 is sandwiched by the cool storage packs 5, in which the cool storage material is under a refrigerating condition of, for example, temperature of -25°C. As a result, at theheat emitter 92, the cool storage material is condensed and liquidized, so that a heat is emitted to the cool storage packs 5, thereby obtaining a so-called heat pipe effect. - In a situation where an emission of an exhaust gas or an operating noise is strongly restricted, it is necessary for a refrigerated vehicle to be provided with means for keeping a low temperature inside the refrigerating compartment under a stopped condition of an internal combustion engine of the refrigerated vehicle. In view of this requirement, a technic has been proposed, where a cool storage material sealingly stored in a metal container is frozen at night by using an outside electric power source. During transportation by a refrigerated vehicle, latent heat generated when the cool storage material is melted is used for keeping a low temperature inside the refrigerating compartment without operating the refrigerating system. However, this prior art is disadvantageous due to an increased weight and manufacturing cost due to the use of the metal container. Thus, a proposal is made wherein the container is made of a plastic material. However, such a container made of a plastic material is disadvantageous due to a large thermal resistance, thereby reducing a cool keeping capacity when compared with the metal container. Contrary to this, in the above mentioned seventh embodiment, the
rounded tube 90 of theheat accumulating evaporator 14 is constructed so as to function as a heat pipe. Due to the employment of the heat pipe construction, an increase in the heat absorbing capacity is obtained, thereby providing a desired cool keeping operation, even if the container for constructing the cool storage packs 5 is made of plastic material. In the seventh embodiment as illustrated above, therounded tube 90 is arranged so that its extends vertically along the length thereof in order to construct the heat absorber as constructed to be function as a heat pipe. However, a refrigerant pipe extending horizontally can obtain a similar heat pipe function for executing the cool keeping operation so long as the heat emitter of the cool storage packs 5 is not inclined downwardly with respect to a horizontal direction. - Now, result of a test by the inventor will be explained with respect to the construction of the seventh embodiment. The test was done when the outside air temperature was 35°C with regard to the refrigerating compartment of a length of 2960 mm, of width of 1600 mm, of a height of 1690 mm and of a wall thickness of 75 mm. Furthermore, for cool storage evaporator of a refrigerating system for a refrigerated vehicle, in addition to the construction in the seventh embodiment of the rounded
tube 90 with the heat pipe function, a construction of a prior art with a refrigerant pipe with the heat pipe function were prepared. For both of the apparatus in the present invention and in the prior art, the temperature inside the refrigerating compartment after the freezing of the cool storage material was detected. The results are shown in Fig. 18. Namely, a solid curve shows a change in a temperature inside the refrigerating compartment after the completion of the freeze for the construction of the seventh embodiment, while a dotted curve shows a result for a conventional structure. As will be clearly seen from the result of the test in Fig. 18, the present invention can maintain an inside temperature lower than -5°C even after lapse of 60 minutes. Contrary to this, in the conventional structure, the inside temperature is higher than -5°C when 60 minutes has lapsed from the completion of the freeze. In short, an improvement in the cool keeping capacity is obtained by the structure of the present invention. - Fig. 19 shows a
cool storage evaporator 14, in the eighth embodiment, which is arranged on a side wall the refrigerating compartment on a refrigerated vehicle. Namely, thecool storage evaporator 14 includes six cool storage packs 5 each including a container made of a plastic material of an increased heat conductivity for storing therein a cool storage material, and a rounded tube 35 including vertically spacedstraight portions 95 extending horizontally and looped portions 95-1 connecting thestraight portions 95 with each other. In place of the construction of the rounded tube 35 in Fig. 19, a construction of the roundedtube 90 in Fig. 16 can be employed in order to improve the heat conducting capacity as well as the refrigerating capacity. - In Fig. 19, the six cool storage packs 5 are arranged to surround the four straight portions of the rounded
tube 95. Namely, eachpack 5 is constructed by a first and a second members 5-1 and 5-2, which are faced with each other by way of the straight portions of the roundedtube 95, thereby obtaining the structure. Furthermore, in the vertical direction, two packs are arranged, while, in the horizontal direction, three packs are arranged. In Fig. 19, only one pack is shown, and remaining five packs are not shown for the sake of the simplicity. Furthermore, anattachment device 200 is provided for fixedly connecting thecool storage evaporator 14 to an inner side wall of therefrigerating compartment 3. Theattachment device 200 includes two vertically extending ended fixingmembers 201, two vertically extending intermediate fixingmembers 202, six vertically extending rearside fixing members 203, three vertically extending frontside fixing members 204 and fixingmembers 205 such as screws or bolts for connecting the fixingmembers refrigerating compartment 3. - Each of the
end fixing members 201 is made from a metal plate of a substantially C-cross sectional shape and is formed with vertically spaced openings, to which the straight portions of thetube 5 are inserted, respectively, so that the U-shaped portions 95-1 are projected out of themember 201. Furthermore, theend fixing member 201 is further formed withholes rounded hole 211 has an inner diameter larger than that of therounded hole 212. - The
intermediate fixing members 202 are arranged between theend fixing members 201 and each is formed as a metal plate of a substantially Z-cross sectional shape. Furthermore, theintermediate fixing member 202 forms vertically spaced holes, through which the straight portions of thetube 5 are inserted. Finally, theintermediate fixing member 202 forms roundedholes 213, through which the screws orbolts 205 are inserted. - The rear
side fixing members 203 are arranged between thecool storage evaporator 14 and the side wall of therefrigerating compartment 3 and are, each, constructed by a metal plate of a cross-sectional shape as shown in Fig. 19. In detail, three vertical pairs of fixingmembers 203, which are arranged symmetric and contacted along their faced vertical edges, are provided. These vertical pairs are arranged between theplates plates 213 and between theplates side fixing member 203 forms roundedholes bolts 205. - The front
side fixing members 204 are arranged so as to be extended vertically and are arranged between theplates plates 213 and between theplates side fixing members 204 face corresponding pairs of the rearside fixing members 203. Furthermore, between frontside fixing member 204 and the pair of the rearside fixing members 203, two vertically spaced cool storage packs 5 are arranged, each pack includes the first and second members 5-1 between which the four straight pipe portions are arranged. Finally, the frontside fixing member 204 forms roundedholes screws 205. - The
screw members 205 are, at the final stage of a mounting process, introduced into theholes 216 of thefront plates 204 and then into theholes 214 of therear plates 203 and introduced into theholes 217 of thefront plates 204 and then into theholes 215 of therear plates 203, so that thescrew members 205 can be tightened. Due to such a tightening force, the cool storage packs 5 are fixed between the facedfront plates 204 and therear plates 203, while the refrigeratingtubes 95 are held by the cool storage packs 5, thereby obtaining the cool storage evaporator assembly. Then, thescrew 205 are inserted to theholes 211 and then to thehole 212 of theupright members 201. Furthermore, thescrews 205 are inserted to theholes 213 of theupright members 202, so that the cool storage evaporator assembly is connected to the inner side wall of therefrigerating compartment 3. - Figs. 20 and 21 show a cool storage evaporator in a ninth embodiment. The
cool storage evaporator 14 in this embodiment is connected to aceiling 300 of therefrigerating compartment 3. Thecool storage evaporator 14 is constructed by agroup 301 ofpacks 5 arranged in a matrix (3 × 4 = 12). Eachpack 5 is constructed by a container for storing therein a cool storage material. The container has at its bottom surface grooves 5-3 along the length thereof. Thecool storage evaporator 14 is further included with arounded tube 95 of a serpentine shape for cooling the cool storage material in thepacks 5, aresilient plate 302 to be arranged between thepacks 5 and theceiling 300, and a box shapedcasing 303 with opened top for storing therein thepacks 5, thetube 95 and theresilient plate 312. - The
resilient plate 312 is formed generally as a rectangular plate shape constructed by a sponge, an air cushion, rubber or a plate spring. Theresilient plate 302 is, as shown in Fig. 20, constructed as aflat plate portion 311 for urging the array of thepacks 5 toward the bottom of thecasing 303, a pair ofside walls 312 extending along the width of theflat plate portion 311 and a pair ofside walls 313 extending along the length of theflat plate portion 311. Theside walls casing 303 and thepacks 5. - The box shaped
casing 303 with bottom is made from metal plate of a high heat conductivity by pressing. Namely, thecasing 303 is formed withopposite walls 321 extending along the width,opposite walls 322 extending along the length, and abottom wall 323 of an elongated rectangular shape. Thecasing 303 is further formed withflanges 324 extending horizontally from theside walls 321 at their top portions. Theflanges 324 are formed with rounded holes 324-1 for screws or bolt for connecting the casing thetop wall 300 of therefrigerating compartment 3. Finally, thebottom wall 323 of thecasing 303 is formed withgroove 325 of a arc-shaped cross-sectional shape. Furthermore, thegroove 325 extends along the serpentine shape of thetube 95 constructed by the straight portions and the U-shaped portions, so that thetube 95 is, at its lower side, fitted to thegroove 325 as shown in Fig. 21. As shown in Fig. 20, theside wall 321 of thecasing 303 is formed with ahole 326 for inserting the inlet part of thetube 95 and ahole 327 for inserting the outlet part of thetube 95. - The ninth embodiment in Figs. 20 and 21 is advantageous in that the number of parts are reduced, on one hand, and a work for mounting is reduced, on the other hand. Furthermore, a resilient mounting of the cool storage packs 5 are realized, which is advantageous in preventing the packs from being damaged during the mounting. Namely, in the ninth embodiment, the flanges 324-1 of the
casing 303 are directly connected to the innertop wall 300 of therefrigerating compartment 3 without using any additional parts, such as theupright members 201 to 204 in the eighth embodiment. Thus, the cost is reduced in view of the fact that the number of parts is reduced and that the work for the mounting is reduced. Furthermore, in a connected condition of thecool storage evaporator 14 to theceiling wall 300 of therefrigerating compartment 3 as shown in Fig. 21, theresilient plate 302 exists between theceiling wall 300 and the cool storage packs 5. Thus, when a cubical expansion of the cool storage material in thepacks 5 due to the freezing of the cool storage material is generated as shown in Fig. 22, theresilient plate 302 is deformed, so as to absorb the expansion, thereby preventing thepacks 5 from being damaged. Furthermore, theresilient member 302 functions, also, to absorb a vibration generated due to the running of the refrigerated vehicle, thereby preventing the vibration from being transmitted to the cool storage packs 5, thereby preventing the plastic containers of thepacks 5 from being damaged. - Now, a tenth embodiment of the present invention will be explained. The construction of the
refrigerating system 1 for a refrigerated vehicle is the same as that shown in Fig. 1 with reference to the first embodiment. Fig. 23 shows a control panel of the tenth embodiment, which includes, in addition to the elements shown in Fig. 4 with reference to the first embodiment, a relay including acoil 47 and a normally openedrelay switch 48 arranged parallel to therelay switch 45 of therelay 41 for controlling an on-off operation of theinner fan motor 32. A fixed resistor 49 is arranged in series to therelay contact 45. The resistor 49 is for obtaining a low rotational speed of theinside fan motor 32, i.e., a low air flow amount L₀ by theinside fan 31 when therelay switch 45 is made ON while therelay switch 48 is made OFF. Contrary to this, when therelay switch 48 is made ON, the resistor 49 is shunted, which causes the rotational speed of theinside fan motor 32 to be increased, thereby obtaining a large air flow amount H₁. Stoppage of theinside fan motor 32 is obtained when both of the relay switches 44 and 45 are made OFF. - In the embodiment, in place of the relay circuit as shown in Fig. 23 (Fig. 4), a semiconductor switching circuit may be used for operating the
inside fan motor 32. Furthermore, in place of obtaining a step-like change in the rotational speed of the fan motor 32 (an air flow amount by the fan 31) by the step-like change in the electric current in thefan motor 32 due to the fixed resistor 49, a continuous change of the rotational speed of the inside fan motor 32 (continuous change in the air flow amount of the inside fan 31) can be obtained by a continuous change in the electric current by a continuously variable resistor. - Now, an operation of the tenth embodiment will be explained with reference to the flow chart in Fig. 24. This flowchart is similar to that in Fig. 5 except that steps S11, S12, S13 and S14 are provided. After the execution of the steps S1 and S2, as shown in Fig. 5, the routine goes to step S11, where a first, a second and a third values preset temperatures T1, T2 and T3 are calculated in accordance with the set temperature set by the inside temperature set switch. Then, the routine flows into steps S4 and S5. During a cool down operation after the cool storage or cool keeping operation, i.e., at the initial stage after the cool storage or cool keeping operation, the inside temperature Ta detected by the
inside temperature sensor 37 would be higher than a third predetermined value T3 which is equal to the set inside temperature Ts plus predetermined value α such as 10°C. As a result, the cooling down operation would cause the routine to go to step S14, where theelectromagnetic clutch 18 of thecompressor 11 and theoutside fan motor 34 are made ON, while theflow switching valve 17 is made OFF. Furthermore, therelay coil 41 is de-energized to cause theswitch 45 to be made OFF, while therelay coil 47 is energized to makeswitch 48 ON, so that an increased electric current is obtained, thereby obtaining a high rotational speed Hi of theinside fan motor 32. Contrary to this, during the usual cooling operation, the inside temperature Ta is lower than the third predetermined value T3, which causes the result of the judgement at step S12 to be No, so that the routine goes to step S13, where theelectromagnetic clutch 18 of thecompressor 11 and theoutside fan motor 34 are made ON, while theflow switching valve 17 is made OFF. Furthermore, therelay coil 41 is energized to cause theswitch 45 to be made ON, while therelay coil 47 is de-energized to makeswitch 48 OFF. As a result, a reduced electric current is obtained due to the resistor 49, so that a low rotational speed Lo of theinside fan motor 32 is obtained. In this embodiment, the result of determination of NO at step S6 may directly lead to step S9. - In the tenth embodiment, the larger air flow amount Hi, larger than the normal value Lo, is obtained when the system is under a cool down operation. At the cool down operation, the temperature inside the
refrigerating compartment 3 is higher than the set temperature Ts plus the predetermined value, i.e., the inside temperature Ta is higher than the set temperature T3. As result, the evaporating temperature of the refrigerant at the refrigerant evaporator becomes larger than the melting point of the cool storage material. As a result, in the cool storage packs 5, the cool storage material located adjacent theround tube 25 of thecool storage evaporator 14 is melted by a latent heat of melting of the cool storage material, which causes the enthalpy at the inlet of therefrigerant evaporator 15 to be reduced for a value of m in Fig. 25(C). Thus, in comparison with the normal refrigerating operation, an increased cooing capacity is obtained during the cooling down operation. Namely, in Fig.25, curve (a) is a Mollier diagram during the normal refrigerating operation, where a low speed rotation (a low flow amount L₀) of theinside fan 31 is obtained. In this case, a major portion j of the increase in the enthalpy during the evaporating periods is occupied by the cooling of the compartment. Curve (b) shows a Mollier diagram during the cool storage operation. In this case, the pressure is lowered and a major portion k of the increase in the enthalpy during the evaporating periods is occupied by the cool storage operation. Curve (c) shows a Mollier diagram during a high load operation, where a rotational speed of the fan is high, i.e., the air flow amount is as large as L₁. In this case, the pressure of the refrigerant is increased and the cool storage material is melted, which causes the enthalpy change n during the evaporating period to be increased. - The present invention can also be used for a refrigerating system for a stationary type container or refrigerator or for other any types of appliances with refrigerating capability.
Claims (12)
- A refrigerating system comprising:
a heat insulated chamber;
means for generating air flow recirculated in the chamber;
means arranged in the chamber for holding an amount of cool storage material;
a compressor for compressing refrigerant;
a condenser for receiving the compressed refrigerant from the compressor via an expansion valve for reducing the pressure of the refrigerant from the condenser;
a first evaporator for receiving the refrigerant of the reduced pressure for cooling the cool storage material;
a second evaporator for receiving the refrigerant of the reduced pressure for cooling the air flows recirculated in the chamber;
a closed passageway of the refrigerant being constructed by the compressor, the condenser, the temperature sensitive expansion valve, the first evaporator and the second evaporator;
said expansion valve being of a type capable of controlling the amount of the recirculated refrigerant in accordance with the temperature of the refrigerant at an outlet side of the second evaporator;
said first and second evaporators being arranged in series with each other;
the expansion valve being arranged in the closed passageway at a location upstream from the first evaporators, and;
means for obtaining switching between refrigerating condition where the flow of the recirculated air by means of the air flow generating means is obtained and a cool storage condition where the flow of the recirculated air by means of the air flow generating means is canceled. - A refrigerating system according to claim 1, wherein said switching means comprise sensor means, for detecting a temperature inside the chamber, and means for controlling the air flow generating means in such a manner that the latter is energized when the temperature inside the chamber is higher than a predetermined value and is de-energized when the temperature inside the chamber is lower than the predetermined value.
- A refrigerating system according to claim 1, wherein the cool storage material has a solidifying temperature which is substantially the same as an evaporating temperature of the refrigerant when the temperature inside the chamber is reduced to a temperature lower than the predetermined value.
- A refrigerating system according to claim 1, wherein it further comprises, in addition to the closed passageway, an additional passageway for connecting the recirculating passageway at a location between the compressor and the condenser with the recirculating passageway at a location between the first and second evaporators, and a switching means of obtaining a switching between a condition where the flow of the refrigerant along the closed passageway, i.e., the refrigerant from the compressor is passed through the condenser, the expansion valve and the first evaporator and is introduced into the second evaporator, and a condition where the refrigerant from the compressor is passed through the additional passageway and is introduced into the second evaporator.
- A refrigerating system according to clam 1, wherein said temperature sensitive expansion valve comprises a first variable orifice in the recirculating passageway, a second variable orifice located downstream from the first orifice, and an actuator responsive to the temperature of the refrigerant at the outlet of the evaporators for controlling the first and second orifices in such a manner that, during the cool storage operation, an adiabatic expansion of the refrigerant occurs at the first orifice, while, during the refrigerating operation, an adiabatic expansion of the refrigerant occurs at the second orifice.
- A refrigerating system according to claim 1, further comprising a sensor means for detecting a temperature inside the chamber, and means for controlling the air flow generating means in such a manner that an increased amount of the air flow is obtained when the temperature inside the chamber is higher than a predetermined value during the refrigerating operation.
- A refrigerating system according to claim 1, further comprising a valve device located in the recirculating passageway at a location between the condenser and the evaporators, and a by-pass opening by-passing the valve device such that, during the cool storage operation, the valve is closed so that an adiabatic expansion of the refrigerant occurs at the by-pass opening but, during the refrigerating operation, an adiabatic expansion of the refrigerant occurs at the valve device.
- A refrigerating system according to claim 1, further comprising means for obtaining switching between a refrigerating condition where the flow of the recirculated air by means of the air flow generating means is obtained and a cool keeping condition where the flow of the recirculated air by means of the air flow generating means is canceled while the compressor is stopped when a condition is obtained where the cool storage material is substantially fully solidified.
- A refrigerating system comprising:
a heat insulated chamber;
means for generating a flow of air recirculated in the chamber;
means arranged in the chamber for holding an amount of cool storage material;
a compressor for compression of a refrigerant;
a condenser for receiving the compressed refrigerant from the compressor;
an expansion valve for reducing the pressure of the refrigerant from the condenser;
a first evaporator for receiving the refrigerant of the reduced pressure for cooling the cool storage material, and;
a second evaporator for receiving the refrigerant of the reduced pressure for cooling the air flow recirculated in the chamber;
a closed passageway of the refrigerant being constructed by the compressor, the condenser, the temperature sensitive expansion valve, the first evaporator and the second evaporator;
said expansion valve being of a type capable of controlling the amount of the recirculated refrigerant in accordance with the temperature of the refrigerant at an outlet side of the second evaporator;
said cool storage evaporator comprising a plurality of packs, each of which includes a container for storing therein a cool storage material, and a tube of a serpentine arrangement which is located in the refrigerant recirculating passageway and which is in contact with the cool storage material. - A refrigerating system according to claim 9, wherein said serpentine tube include portions projected out of and located below said packs.
- A refrigerating system according to claim 9, wherein each of the packs is constructed by a first and second parts, which are connected with each other while the straight portions are arranged between the first and second parts.
- A refrigerating system according to claim 9, wherein the cool storage packs are stored in a casing opened at the top, the casing having a closed bottom for receiving the serpentine tube, on which the packs are arranged, and a resilient plate is arranged at the top of the packs in the casing, so that the resilient plate is located between the packs and a wall of the chamber.
Applications Claiming Priority (8)
Application Number | Priority Date | Filing Date | Title |
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JP20724994 | 1994-08-31 | ||
JP207249/94 | 1994-08-31 | ||
JP1019195 | 1995-01-25 | ||
JP10191/95 | 1995-01-25 | ||
JP74925/95 | 1995-03-31 | ||
JP7492595 | 1995-03-31 | ||
JP156196/95 | 1995-06-22 | ||
JP7156196A JPH08327169A (en) | 1994-08-31 | 1995-06-22 | Refrigerating equipment |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0699883A2 true EP0699883A2 (en) | 1996-03-06 |
EP0699883A3 EP0699883A3 (en) | 1996-07-24 |
Family
ID=27455347
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95113686A Withdrawn EP0699883A3 (en) | 1994-08-31 | 1995-08-31 | Refrigerating system |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0699883A3 (en) |
JP (1) | JPH08327169A (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2329702A (en) * | 1997-09-26 | 1999-03-31 | Gen Motors Corp | Air conditioning system for a motor vehicle |
US6035658A (en) * | 1997-09-26 | 2000-03-14 | General Motors Corporation | Air conditioning system for a motor vehicle |
FR2824388A1 (en) * | 2001-05-07 | 2002-11-08 | Italinnova Sas | COLD GENERATOR FOR VEHICLE AIR CONDITIONING SYSTEM |
DE10308542A1 (en) | 2002-02-28 | 2003-09-11 | Denso Corp | Vehicle air conditioner with cold storage unit |
EP1278031A3 (en) * | 2001-07-19 | 2004-01-21 | TGK Co., Ltd. | Expansion valve unit |
WO2005024314A2 (en) * | 2003-09-05 | 2005-03-17 | Applied Design And Engineering Ltd | Improvements in or relating to refrigeration |
EP1800074A1 (en) * | 2004-07-22 | 2007-06-27 | Era (Environmental Refrigeration Alternatives) Pty Ltd | Refrigeration system |
CN103292388A (en) * | 2013-06-08 | 2013-09-11 | 张家港市江南利玛特设备制造有限公司 | Refrigerating system for engine room |
CN105588376A (en) * | 2016-02-23 | 2016-05-18 | 珠海格力电器股份有限公司 | Refrigerating system, control method thereof and refrigerated transport vehicle |
CN107621091A (en) * | 2017-09-27 | 2018-01-23 | 深圳市英维克科技股份有限公司 | A kind of refrigeration system and electronic refrigerator car |
DE102016223050A1 (en) * | 2016-11-22 | 2018-05-24 | Dometic Sweden Ab | Cooling circuit for a vehicle, in particular for cooling a Kühlgutraums a transport vehicle |
US11833889B2 (en) | 2018-09-13 | 2023-12-05 | Carrier Corporation | Transport refrigeration unit with engine heat for defrosting |
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JP3830239B2 (en) * | 1997-09-29 | 2006-10-04 | カルソニックカンセイ株式会社 | Air conditioner for vehicles |
JP2002115934A (en) * | 2000-10-06 | 2002-04-19 | Denso Corp | Vaporizer and freezer |
JP6699621B2 (en) * | 2017-05-26 | 2020-05-27 | 株式会社デンソー | Refrigeration system |
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US2515825A (en) * | 1945-03-16 | 1950-07-18 | Carrier Corp | Single stage refrigeration utilizing holdover means |
US2922292A (en) * | 1956-05-03 | 1960-01-26 | Sporlan Valve Co | Valve assembly for a refrigeration system |
JPH071128B2 (en) * | 1987-02-27 | 1995-01-11 | 株式会社東芝 | Refrigeration cycle for refrigerator |
IT1244107B (en) * | 1990-09-28 | 1994-07-05 | Costan Spa | REFRIGERATED REFRIGERANT CIRCUIT AND RELATED DEFROSTING METHOD |
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- 1995-06-22 JP JP7156196A patent/JPH08327169A/en active Pending
- 1995-08-31 EP EP95113686A patent/EP0699883A3/en not_active Withdrawn
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Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2329702A (en) * | 1997-09-26 | 1999-03-31 | Gen Motors Corp | Air conditioning system for a motor vehicle |
US6035658A (en) * | 1997-09-26 | 2000-03-14 | General Motors Corporation | Air conditioning system for a motor vehicle |
FR2824388A1 (en) * | 2001-05-07 | 2002-11-08 | Italinnova Sas | COLD GENERATOR FOR VEHICLE AIR CONDITIONING SYSTEM |
EP1278031A3 (en) * | 2001-07-19 | 2004-01-21 | TGK Co., Ltd. | Expansion valve unit |
DE10308542A1 (en) | 2002-02-28 | 2003-09-11 | Denso Corp | Vehicle air conditioner with cold storage unit |
DE10308542B4 (en) * | 2002-02-28 | 2014-09-11 | Denso Corporation | Vehicle air conditioner with cold storage unit |
WO2005024314A2 (en) * | 2003-09-05 | 2005-03-17 | Applied Design And Engineering Ltd | Improvements in or relating to refrigeration |
WO2005024314A3 (en) * | 2003-09-05 | 2005-06-23 | Applied Design & Eng Ltd | Improvements in or relating to refrigeration |
EP1800074A4 (en) * | 2004-07-22 | 2013-03-20 | Era Environmental Refrigeration Alternatives Pty Ltd | Refrigeration system |
EP1800074A1 (en) * | 2004-07-22 | 2007-06-27 | Era (Environmental Refrigeration Alternatives) Pty Ltd | Refrigeration system |
CN103292388A (en) * | 2013-06-08 | 2013-09-11 | 张家港市江南利玛特设备制造有限公司 | Refrigerating system for engine room |
CN105588376A (en) * | 2016-02-23 | 2016-05-18 | 珠海格力电器股份有限公司 | Refrigerating system, control method thereof and refrigerated transport vehicle |
CN105588376B (en) * | 2016-02-23 | 2023-11-24 | 珠海格力电器股份有限公司 | Refrigerating system, control method thereof and refrigerated transport vehicle |
DE102016223050A1 (en) * | 2016-11-22 | 2018-05-24 | Dometic Sweden Ab | Cooling circuit for a vehicle, in particular for cooling a Kühlgutraums a transport vehicle |
DE102016223050B4 (en) * | 2016-11-22 | 2020-03-26 | Dometic Sweden Ab | Cooling circuit for a vehicle, in particular for cooling a refrigerated goods compartment of a transport vehicle |
CN107621091A (en) * | 2017-09-27 | 2018-01-23 | 深圳市英维克科技股份有限公司 | A kind of refrigeration system and electronic refrigerator car |
US11833889B2 (en) | 2018-09-13 | 2023-12-05 | Carrier Corporation | Transport refrigeration unit with engine heat for defrosting |
Also Published As
Publication number | Publication date |
---|---|
JPH08327169A (en) | 1996-12-13 |
EP0699883A3 (en) | 1996-07-24 |
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