US3326277A - Heating and cooling system - Google Patents

Description

June .20, 1967 w. T. OSBORNE 3,326,277

HEATING AND COOLING SYSTEM Original Filed June 22 19 4 moi INVENTOR. WILLIAM T. OSBORNE.

ATTORNEY.

United States Patent 3,326,277 HEATING AND COOLING SYSTEM William T. Osborne, East Syracuse, N.Y., asslgnor to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Original application June 23, 1964, Ser. N 377,262, now Patent No. 3,286,766, dated Nov. 22, 196(. Divided and this application June 8, 1966, Ser. No. 556,084

Claims. (Cl. 165-62) This application is a division of application Ser. No. 377,262, filed June 23, 1964, now Patent No. 3,286,766 granted Nov. 22, 1966, entitled, Heating and Cooling System, and relates broadly to a heating and cooling system wherein a refrigeration system is employed and, more particularly, to improved refrigerant handling means for storing refrigerant in such system.

A copending patent application of Louis H. Leonard for a Heating and Cooling System, Ser. No. 377,319, filed June 23, 1964, now Patent No. 3,288,203 granted Nov. 29, 1966, discloses a system for heating and cooling in which a cooler has a chilled water line flooded with liquid refrigerant for cooling a load during cooling operation of the system, and a steam condenser is purged of noncondensible vapor, preferably refrigerant vapor, to control operation of the system and to provide eflicient heating of a load to be heated. During winter heating operation, When cooling is not required, it may be desirable to withdraw the refrigerant from the normal refrigeration circuit, for example, in order to reduce the load on the purge system. It is also sometimes necessary to withdraw the refrigerant in order to service the machine. In order to facilitate shipping the machine precharged with refrigerant, thus reducing the over-all cost of the equipment when it is installed and ready to operate, some means should be provided to isolate the refrigerant from the refrigerant circuit.

It is a primary object of this invention to provide a new and improved refrigeration system. A related object is provision in such a system for handling and storing refrigerant.

Another object is the provision of a new and improved arrangement for passing refrigerant from a refrigeration circuit to a refrigerant storage vessel upon termination of the refrigeration system. A related object is provision for passing refrigerant from the vessel to the refrigeration circuit upon starting the system in normal cooling operatlon.

Another object is provision of a new and improved refrigeration system including a storage vessel for holding refrigerant when the system is inoperative for cooling, together with a circuit connected with the storage vessel for the passage of liquid refrigerant to the vessel when the system is inoperative for cooling, and operable for withdrawing the refrigerant from the storage vessel and for circulating the refrigerant to cool a load during cooling operation of the system.

Another object of this invention is provision of a neW and improved heating and cooling system for heating a load during heating operation when the system may be inoperative for cooling and in which a refrigerant is circulated through a refrigerant circuit to cool a load during cooling operation of the system, and a storage vessel communicating with a low portion of the refrigerant circuit for draining liquid refrigerant from the refrigerant circuit when the system is inoperative for cooling to provide more eflicient heating and to avoid high refrigerant pressures in the circuit, and for the passage of liquid refrigerant into the circuit upon commencing cooling operation of the system.

Additional objects and advantages of the invention will be apparent from the drawing, in which:

3,326,277 Patented June 20, 1967 FIGURE 1 is a flow diagram of an embodiment of the invention in a heating and cooling system; and

FIGURE 2 is a modification of a portion of FIGURE 1 and illustrates another embodiment of the invention.

The invention is illustrated in the form of a heating and cooling system for providing cooling, heating, or simultaneous heating and cooling. The system is preferably hermetic in that fluids in the system are prevented from escaping and ambient air is prevented from entering the system. The system may be considered as having a power side including a circuit for the circulation of a power fluid, a refrigerant side including a storage vessel for refrigerant and a refrigeration circuit for the flow of a refrigerant fluid under the influence of operating means driven by the power fluid, with the operation of the system regulated by a control system.

The invention will be described with reference to a preferred power fluid, which is water, and a preferred refrigerant, which is octaliuorocyclobutane, commonly referred to as C318 and having a chemical formula C F These fluids are particularly preferred because of their relative immiscibility and because they are inherently highly stable and do not tend to decompose or chemically react with each other or other materials in the system, or cause or promote corrosion or undesirable by-products. Also, this refrigerant is a relatively noncondensible vapor at the temperatures and pressures at which the power fluid (water) condenses, as well as at the usual ambient atmospheric conditions of temperature and pressure. However, other power fluids and refrigerants having these desired chemical and physical properties may be utilized within the scone of this invention.

As illustrated in the drawing, the power side includes a suitable steam generator 12 which supplies steam at a substantially constant pressure (15 p.s.i.g., for example) as controlled by a constant pressure regulating valve 13 in a steam supply line 14 to operating means in the form of a turbocompressor 15 and, more particularly a turbine 16 for driving a compressor 17 and discharging steam through a discharge line 18 to a steam condenser 19. A steam condensate pump 20 returns the steam condensate through a return line 21 from the steam condenser 19 to the steam generator 12 for recirculation through the power side of the system. The turbocompressor 15 has flow restricting means in the form of labyrinth type seals, as 22, for retarding leakage of steams and refrigerant from the turbine 16 and the compressor 17, respectively, and water lubricated bearings, as 23. The steam condensate pump 20 pumps steam condensate through a lubricant water line 24 including a lubricant cooling heat exchanger 25 for lubricating the bearings 23. Leakage from the turbine and compressor, and water from the bearings passes into a chamber 26 and through a drain line 27 to the steam condenser 19.

The refrigerant side of the system includes a refrigerant circuit and refrigerant storage means for holding refrigerant when the system is inoperative for cooling. The refrigerant circuit includes the compressor 17 of the turbocompressor 15. The compressor 17 is drivingly connected with the turbine 16 for passing compressed refrigerant vapor to a refrigerant condenser 28 having a condensing bundle 29. Condensed refrigerant passes from the refrigerant condenser 28 to a refrigerant subcooler 30 in FIG- URE 1, and 30' in FIGURE 2, and through a suitable refrigerant flow metering means 31 in FIGURE 1, and 32 in FIGURE 2, and then through a cooler refrigerant supply line 33 into an evaporator or cooler 34, from which the refrigerant vapor is withdrawn by the refrigerant compressor 17 through a suction line 35, thus completing the refrigeration circuit of the system. The cooler includes a water supply sump 38 and provides means for separating water and refrigerant, as is described in my copending United States patent application for a Cooler, Ser. No. 377,317, filed June 23, 1964, now Patent No. 3,279,210. A line 39 communicates with a tube bundle 40 in the cooler for carrying a heat exchange medium, here in the form of chilled water. The chilled water tube bundle 40 is flooded by liquid refrigerant and is cooled by the refrigerant and circulated by a pump 41 to an area having a cooling requirement. The cooling capacity of the system varies in proportion to the compressor output and general speed.

A cooling tower or condensing water pump 42 circulates tower water through an inlet line 43 to the refrigerant subcooler 30 and into the refrigerant condenser bundle 29 and then the steam condenser bundle 46 and back to the tower through an outlet line 44. A branch line 45 in the condensing water inlet line 43 provides tower water to the lubricant waterheat exchanger 25 for cooling the lubricant water, and this branch terminates in the return line 44 to the tower. In general, control of condensing water temperature and fiow rate is unnecessary, thus minimizing scaling of condensing surfaces in the condensers.

A suitable hot gas bypass 45' may be provided for effectively preventing compressor surge.

The control'system regulates the cooling and simultaneous cooling and heating capacities of the refrigeration system by varying the steam condenser pressure which is related to the condensing rate of steam discharged into the steam condenser 19, as is described in the previously mentioned Leonard application. In brief, the condensing rate of the steam condenser 19 is regulated by controlled blanketing of a first condensing portion or tube bundle 46 with a noncondensible vapor, herein refrigerant vapor, introduced through a refrigerant line 47 from the cooler 34.

The quantity of noncondensible vapor effectively blanketing the first condensing portion 46 of the steam condenser is regulated by a modulating refrigerant flow regulating valve 48 in the line 47. The valve 48 is actuated responsive to chilled water temperature by means of a temperature sensor 49 on the chilled water line 39. For example, as the cooling load drops, more refrigerant is introduced into the steam condenser 19, thus reducing the steam condensing rate to increase the steam condenser pressure andtherefore the temperature of the saturated steam in the condenser, and the turbine discharge pressure to reduce the turbocompressor output and in general the turbocompressor speed.

A purge system withdraws refrigerant from the steam condenser 19, preferably at a constant rate. Herein a constant speed water supply pump 50 in a water line 51 recirculates impeller water from the cooler sump 38 for operating a jet pump 52 in the sump to withdraw noncondensible vapor from the steam condenser 19 through a purge line 53 opening into the throat of the jet pump 52. The water supply pump 50 further provides make-up water for the steam generator 12 through a make-up water line 54 to the steam condenser 19 when a valve 55 in the line 54 is open, as controlled by a float sensor 56 in a steam condensate chamber 57 of the steam condenser 19. The purge line 53 opens into the steam condensate chamber 57 at a level to withdraw steam from the chamber should the condensate level rise too high.

Simultaneous heating and cooling, wherein the heating and cooling capacities of the system vary inversely of each other, is provided. A second condensing portion or tube bundle 58 in the steam condenser 19 is maintained effectively free of blanketing :by refrigerant vapor to maintain its full condensing capacity and maximum heating of a heating medium, herein water, recirculated through the bundle 58, and to a load to be heated by means of a heating water pump 59 in a heating line 60 between the area having a heating requirement and the second condensing portion 58.

The refrigerant injected into the steam condenser 19 through the refrigerant line 47 from the cooler 34 enters the steam condense-r through a refrigerant port -61 at one end of the steam condenser 19 between the first condensing tube bundle 46 and the second condensing tube bundle 58. A baffle 62 extends between upper and lower portions of the steam condenser between the first and second condensing tube bundle 46 and 58, to prevent the flow of fluids therebetween except in a limited area of communication 63 at the refrigerant port 61. The entering steam first flows from the discharge line 18 through a steam condenser inlet port 64 at an end of the condenser 19 opposite the area of limited communication 63, and across the second condensing tube bundle 58, then through the area of limited communication 63 and past the refrigerant inlet port 61, and with the refrigerant vapor, along the first condensing bundle 46.

During cooling operation of the system, the turbine 16 drives the compressor 17 so that refrigerant vapor in the refrigeration circuitis compressed and passes through a compressor discharge line 65 and into the refrigerant condenser 28 where it is condensed and cooled. The refrigerant condensate flows through a refrigerant condensate line 66 into the refrigerant subcooler 30 from which it passes through the refrigerant flow restricting means 31 or 32, here in the form of a float valve unit, and flows through the cooler refrigerant supply line 33 and into a pan 67 spaced above the bottom of the cooler which defines the sump 38. The chiller water bundle 40 is flooded with liquid refrigerant in the pan 67 so that during normal cooling operation of the system, the bundle is supplied with liquid refrigerant which vaporizes and passes through the suction line 35 to the compressor 17.

As is more fully described in my previously mentioned application, refrigerant vapor in the sump 38 passes upwardly about a left end wall 68 of the refrigerant pan 67 and into the suction line 35, and water collects on top of liquid refrigerant in the pan 67 and passes to the left end of the pan from which it flows through a suitable weir or port 69 in the pan end wall 68 and into the sump. Thus, means is provided for separating water and refrigerant and returning the separated fluids for reuse in the system.

To shut down the system when it is in cooling operation, a valve 69' in a line 69" between the refrigerant condenser 28 and the steam condenser 19 is opened to pass a large quantity of refrigerant into the steam condenser, thus increasing the turbine discharge pressure to that of the driving steam for stopping the turbine. The refrigerant in the steam condenser migrates throughout the power side so that the system is pressurized above ambient pressure, thus effectively preventing entry of ambient air into the system.

When it is desired to provide only heating, as for winter heating, the tower water pump 42 is shut off and valve means 70 in the steam supply line 14 to the turbocompressor 15 is adjusted so that the steam bypasses the turbine 16 and is injected through a bypass line 71 into the steam condenser 19 for heating the second condensing bundle 58. During winter heating, the heating capacity of the system is preferably controlled by regulating the steam generator output. Refrigerant may migrate into the steam condenser 19, as from the refrigerant condenser 28 which envelopes t-he steam condenser, or through the turbine drain 27, and must be removed from the steam condenser along with any residual refrigerant therein in order to effect maximum heating of the second tube bundle 58 which provides hot water to the load to be heated. The noncondensible refrigerant vapor is withdrawn through the purge line 53, and the water supply pump 50 is therefore in operation to provide impeller water for the jet pump 52. In order to prevent water from flashing at the jet pump 52, the impeller water must be below the water saturation temperature of the steam condenser 19. Therefore, the water line 51 to the jet pump 52 passes through a jet impeller Water heat exchanger 72 for cooling the impeller water.

The refrigerant storage means is preferably in a rela tively cool area to avoid high refrigerant pressure when storing refrigerant during winter heating operation, and when shipping or servicing the machine, and for reducing the load on the purge system during winter heating operation at which time the refrigeration system is not in operation.

In the embodiment of FIGURE 1, the storage means is in the form of a storage vessel 73 below a low portion of the refrigeration circuit. Passage means in the form of a pipe 74 connects the cooler refrigerant supply line 33 and the storage vessel 73 for draining liquid refrigerant from the refrigeration circuit. The float unit 31 is at the lowest portion of the refrigeration circuit and in the embodiment of FIGURE 1 is formed integrally with one end of the subcooler 30. A vent or equalizer line 75 connects the chamber of float valve 31 and the refrigerant condenser 28, and the storage vessel 73 is vented to the equalizer line 75 by means of a conduit 76. Both the pipe 74 and conduit 76 are provided with suitable valves 77 and 78, respectively, to prevent refrigerant from passing from the refrigeration circuit into the storage vessel 73 during normal cooling operation of the system.

Upon stopping cooling operation of the system, the refrigerant pressure throughout the refrigeration circuit rises to about 50 p.s.i.g. During winter heating operation, when the refrigeraion circuit is inoperative for cooling and steam to the steam condenser bypasses the turbine 16, the pressure in the refrigeration circuit could rise substantially higher and possibly render the purge system inoperative. Therefore, prior to heating operation, the valves 77 and 78 in the lines to the storage vessel 73 are opened and liquid refrigerant is drained from the refrigeration circuit. In order to remove refrigerant vapor from the refrigeration circuit, the tower water pump 42 may be maintained in operation to pass tower water through the subcooler 30 and refrigerant condenser 29 to condense the vapor which then flows into the vessel. Furthermore, the shell of the storage vessel 73 may be cooled as by running cool water over it, or a suitable conduit such as a condensing tube bundle 79 may be provided in the storage vessel 73 for connection with a suitable source of cool water, to condense vapor in the vessel and provide a low pressure area therein, so that refrigerant vapor passes into the storage vessel. When the refrigerant in the refrigeration circuit has passed into the storage vessel, the valves 77 and 78 are closed to prevent the refrigerant from passing back into the refribgeration circuit.

In the embodiment shown in FIGURE 1, the storage vessel 73 may be secured to the heating and cooling machine, or it may be installed in a location remote from the machine and connected therewith by relatively small size tubing.

In the embodiment shown in FIGURE 2, a storage vessel 80 is preferably mounted on the machine and is again at a low portion of the refrigeration circuit. The float valve unit 32 is integral with an end of the storage vessel 80 and the storage vessel is :between the subcooler 30 and the cooler 34. A drain and vent standpipe 81 extends upwardly from an upper portion of a shell forming the storage vessel 80 and the chamber of the float valve unit 32, and opens into the discharge end of the subcooler 30. The .standpipe 81 has a drain port 82 for the passage of refrigerant into the storage vessel 80. As previously described, upon stopping cooling operation of the system, refrigerant liquid drains to the lowest portion of the cincuit and into the storage vessel 80. Refrigerant vapor in the refrigeration circuit may be passed into the storage vessel 80 either by first condensing the vapor in the refrigeration circuit or by condensing the vapor in the storage vessel, as previously described. After the refrigerant has passed into the storage vessel 80, suitable valves 83 and 84 in the standpipe and cooler refrigerant supply line, respectively, may be closed for retaining the refrigerant in the storage vessel.

Preparatory to cooling operation, the storage vessel valves either 77 and 78 in FIGURE 1, or 83 and 84 in FIGURE 2, are opened, again pressurizing the machine. Upon starting, the purge system slowly removes refrigerant vapor from the power side and particularly from the steam condenser 19 for slowly starting the turbocompressor in operation. As the turbocompressor slowly comes up to design speed, a pressure differential is created between the refrigerant condenser and the cooler to force the refrigerant (liquid and vapor, if any) in the storage vessel 73 or into the cooler. By the time the turbocompressor reaches design speed (25,000 r.p.-m. in 15 minutes, for example) the liquid refrigerant has been transferred from the storage vessel to the cooler 34 and the system is in normal cooling operation. With reference to the embodiment of FIGURE 1, when the refrigerant is again in the refrigeration circuit, the storage vessel valves may be closed to prevent refrigerant from circulating through the storage vessel and producing an additional load on the compressor.

While this invention has been described and illustrated in a preferred embodiment, it will be understood that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

I claim:

1. In a refrigeration system, the combination comprising, a refrigeration circuit including a high pressure portion and a low pressure portion including a cooler having a chilled water line to be flooded in a body of liquid refrigerant to cool a load during cooling operation of the system, a storage vessel communicating with a low portion of said refrigeration circuit between .said high and low pressure portions for draining liquid refrigerant from said circuit into said vessel when the system is inoperative for cooling and for the passage of the refrigerant from said vessel into said cooler when the system is operative preparatory to cooling.

2. The system of claim 1, and condensing means operable to condense the refrigerant vapor when the system is inoperative for cooling, whereby the resultant liquid drains into said storage vessel.

3. In a refrigeration system, the combination comprising, a power side having a portion normally at a pressure below atmospheric pressure during cooling operation of the system, means for pressurizing said power side with refrigerant vapor when the system is inoperative for cooling, a refrigerant side including, a refrigeration circuit having a cooler with a chilled water line to be flooded m a body of liquid refrigerant for cooling a load, a refrigerant compressor driven by said power side for withdrawing refrigerant vapor from the cooler to provide a low pressure area therein during cooling operation of the system, and a closed storage vessel at a low portion of said refrigerant side, means selectively operable when the system is inoperative for cooling to provide a temperature in a portion of the refrigerant side to condense refrigerant vapor, means selectively operable for passing the pressurizing refrigerant vapor from said power side to said refrigerant side when the system is inoperative for cooling, and connecting means providing communication between said vessel and a low portion of said refrigeration c rcuit for draining liquid refrigerant from said refrigeration circuit into the vessel when the system is inoperative for cooling and for the passage of the refrigerant from the vessel to the cooler when the system is operative for cooling.

4. In the system of claim 3, said refrigeration circuit including refrigerant flow metering means in a low portion of the refrigeration circuit for metering refrigerant to said cooler, said storage vessel being below said refrigerant flow metering means, and said connecting means opening into said refrigeration circuit on opposite sides of said refrigerant flow metering means.

5. In the system of claim 3, said refrigeration circuit including a refrigerant condenser and refrigerant flow 7 8 metering means between said condenser and said cooler, References Cited said refrigerant flow metering means including a cham- UNITED STATES PATENTS her for refrigerant, sald chamber dependmg frcm sa d 3,065,610 11/1962 Maudlin storage vessel, and said connecting means 1nc1ud1ng said chamber 0 enin into said vessel and assa e means com- 5' 3O74249 1/1963 Henderson 62 149 P g P g 3,153,442 10/1964 Silvern 16550 municating With said chamber and opening into said refrigeration circuit between said chamber and said re- MEYER PERLIN, Primary Examiner.

frigerant condenser C. SUKALO, Assistant Examiner.

Claims (1)

1. 3. IN A REFRIGERATION SYSTEM, THE COMBINATION COMPRISING, A POWER SIDE HAVING A PORTION NORMALLY AT A PRESSURE BELOW ATMOSPHERIC PRESSURE DURING COOLING OPERATION OF THE SYSTEM, MEANS FOR PRESSURIZING SAID POWER SIDE WITH REFRIGERANT VAPOR WHEN THE SYSTEM IS INOPERATIVE FOR COOLING, A REFRIGERANT SIDE INCLUDING, A REFRIGERATION CIRCUIT HAVING A COOLER WITH A CHILLED WATER LINE TO BE FLOODED IN A BODY LIQUID REFRIGERANT FOR COOLING A LOAD, A REFRIGERANT COMPRESSOR DRIVEN BY SAID POWER SIDE FOR WITHDRAWING REFRIGERANT VAPOR FROM THE COOLER TO PROVIDE A LOW PRESSURE AREA THEREIN DURING COOLING OPERATION OF THE SYSTEM, AND A CLOSED STORAGE VESSEL AT A LOW PORTION OF SAID REFRIGERANT SIDE, MEANS SELECTIVELY OPERABLE WHEN THE SYSTEM IS INOPERATIVE FOR COOLING TO PROVIDE A TEMPERATURE IN A PORTION OF THE REFRIGERANT SIDE TO CONDENSE REFRIGERANT VAPOR, MEANS SELECTIVELY OPERABLE FOR PASSING THE PRESSURIZING REFRIGERAN VAPOR FROM SAID POWER SIDE TO SAID REFRIGERANT SIDE WHEN THE SYSTEM IS INOPERATIVE FOR COOLING, AND CONNECTING MEANS PROVIDING COMMUNICATION BETWEEB SAID VESSEL AND A LOW PORTION OF SAID REFRIGERATION CIRCUIT FOR DRAINING LIQUID REFRIGERANT FROM SAID REFRIGERATION CIRCUIT INTO THE VESSEL WHEN THE SYSTEM IS INOPERASTIVE FOR COOLING AND FOR THE PASSAGE OF THE REFRIGERANT FROM THE VESSEL TO THE COOLER WHEN THE SYSTEM IS OPERATIVE FOR COOLING.

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