WO2020158888A1 - Air conditioner - Google Patents
Air conditioner Download PDFInfo
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- WO2020158888A1 WO2020158888A1 PCT/JP2020/003518 JP2020003518W WO2020158888A1 WO 2020158888 A1 WO2020158888 A1 WO 2020158888A1 JP 2020003518 W JP2020003518 W JP 2020003518W WO 2020158888 A1 WO2020158888 A1 WO 2020158888A1
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- refrigerant
- expansion valve
- temperature
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- target
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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
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
Definitions
- the present disclosure relates to an air conditioner.
- Some outdoor units of air conditioners have a medium-pressure receiver between the condenser and the evaporator, and expansion valves before and after the medium-pressure receiver.
- the two expansion valves are controlled by SC (subcool: supercooling) control of the upstream (condensing side) expansion valve during the heating operation and intake of the downstream (evaporation side) expansion valve during the heating operation SH.
- SC subcool: supercooling
- suction superheat superheat of suction
- the opening degree of the condensation side expansion valve since the opening degree is controlled so that SC reaches a predetermined target value, it is difficult for SC to reach the target value (for example, during operation when the circulation amount of the refrigerant is small or During the cooling operation under high outside temperature), the opening degree of the condensation side expansion valve becomes excessively small.
- the refrigerant does not flow out from the condenser, so the liquid refrigerant accumulates inside the condenser.
- the amount of liquid refrigerant in the medium-pressure receiver decreases, and the amount of refrigerant flowing to the evaporator decreases, so even if the opening of the evaporator-side expansion valve is increased, it is drawn into the compressor.
- the evaporating side expansion valve does not function because the dryness of the refrigerant is not lowered. As a result, there arise problems that the reliability of the compressor is reduced and the rotation speed is reduced due to the occurrence of the protection operation.
- the air conditioner of the present disclosure has a refrigerant circuit, a control unit, a condensation temperature sensor, a condenser outlet temperature sensor, and a condenser ambient temperature sensor.
- a refrigerant pipe is connected so that the refrigerant flows in the order of the compressor, the condenser, the condensation side expansion valve, the intermediate pressure receiver, the evaporation side expansion valve, and the evaporator.
- the control means controls the condensation side expansion valve and the evaporation side expansion valve.
- the condensation temperature sensor detects the condensation temperature.
- the condenser outlet temperature sensor detects the condenser outlet temperature which is the temperature of the refrigerant flowing out from the condenser.
- the condenser ambient temperature sensor detects the ambient temperature of the condenser. Then, the control means performs SC control for controlling the opening degree of the condensation side expansion valve so that the SC value, which is the difference between the condensation temperature and the condenser outlet temperature, becomes the target value SCt, and the difference ⁇ t between the condensation temperature and the ambient temperature.
- the target value SCt is changed accordingly.
- an air conditioner including a medium pressure receiver it is possible to suppress deterioration in reliability of the compressor.
- FIG. 3 is a Mollier diagram (ph diagram) relating to the refrigerant circuit of FIG. 2. It is a figure explaining the refrigerant circuit which has an injection circuit.
- FIG. 5 is a Mollier diagram (ph diagram) relating to the refrigerant circuit of FIG. 4. It is a figure explaining the refrigerant circuit provided with the intermediate pressure receiver in the air conditioner of the embodiment of this indication.
- FIG. 7 is a Mollier diagram (ph diagram) relating to the refrigerant circuit of FIG. 6.
- FIG. 9 is a Mollier diagram (ph diagram) relating to the refrigerant circuit of FIG. 8.
- FIG. It is an operation
- an air conditioner 1 includes an outdoor unit 2 installed outdoors and an indoor unit 3 installed indoors and connected to the outdoor unit 2 by a liquid pipe 4 and a gas pipe 5. Equipped with. Specifically, the liquid-side shutoff valve 25 of the outdoor unit 2 and the liquid pipe connecting portion 33 of the indoor unit 3 are connected by the liquid pipe 4. Further, the gas side closing valve 26 of the outdoor unit 2 and the gas pipe connecting portion 34 of the indoor unit 3 are connected by the gas pipe 5. As described above, the refrigerant circuit 10 of the air conditioner 1 is formed.
- the outdoor unit 2 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, a first expansion valve 24 during heating operation, a liquid side closing valve 25 to which the liquid pipe 4 is connected, and a gas pipe 5 Is connected to the gas side closing valve 26, the outdoor fan 27, the second expansion valve 28 during the heating operation, the injection expansion valve 29, the intermediate pressure receiver 81, and the heat exchanger 82 between refrigerants.
- the respective devices except the outdoor fan 27 are connected to each other by respective refrigerant pipes described later to form an outdoor unit refrigerant circuit 10a forming a part of the refrigerant circuit 10.
- An accumulator (not shown) may be provided on the refrigerant suction side of the compressor 21.
- injection may be described as "INJ.”
- the compressor 21 is a variable capacity compressor whose operating capacity can be changed by controlling the rotation speed by an inverter (not shown).
- the refrigerant discharge side of the compressor 21 is connected to the port a of the four-way valve 22 by a discharge pipe 61.
- the refrigerant suction side of the compressor 21 is connected to the port c of the four-way valve 22 by a suction pipe 66.
- the intermediate pressure receiver 81 is provided in the outdoor unit liquid pipe 63 between the liquid side closing valve 25 and the outdoor heat exchanger 23, sandwiched between the first expansion valve 24 and the second expansion valve 28.
- the medium pressure receiver 81 is for adjusting the amount of refrigerant to an appropriate amount, even if the indoor units 3 of various sizes are connected.
- An injection pipe (also referred to as an injection circuit) 65 is branched on the downstream side of the intermediate pressure receiver 81, and the injection pipe 65 is connected to an intermediate portion of a cylinder (not shown) inside the compressor 21 via an injection expansion valve 29. There is.
- the injection pipe 65 is for injecting the refrigerant into the compressor 21 in order to increase the refrigerant circulation amount of the condenser (the indoor heat exchanger 31 during the heating operation) or lower the discharge temperature of the compressor 21.
- An inter-refrigerant heat exchanger 82 that exchanges heat between the refrigerant flowing through the injection pipe 65 and the refrigerant flowing through the outdoor unit liquid pipe 63 is provided in the middle of the injection pipe 65.
- a series of circuits including the injection pipe 65 and the injection expansion valve 29 is referred to as an injection circuit (in this specification, the injection pipe 65 is a representative example of an injection circuit.
- the injection circuit shown here is an example. And other modes may be used).
- the injection expansion valve 29 can be fully closed, is provided as an opening/closing means for the injection pipe 65, and controls the discharge temperature or the discharge SH of the compressor 21.
- the four-way valve 22 is a valve for switching the flowing direction of the refrigerant, and has four ports a, b, c, d.
- the port a is connected to the refrigerant discharge side of the compressor 21 by the discharge pipe 61 as described above.
- the port b is connected to one refrigerant inlet/outlet of the outdoor heat exchanger 23 by a refrigerant pipe 62.
- the port c is connected to the refrigerant suction side of the compressor 21 by the suction pipe 66 as described above.
- the port d is connected to the gas side closing valve 26 by the outdoor unit gas pipe 64.
- the four-way valve 22 is the flow path switching unit of the present disclosure.
- the outdoor heat exchanger 23 is for exchanging heat between the refrigerant and the outside air taken into the outdoor unit 2 by the rotation of an outdoor fan 27 described later.
- one refrigerant inlet/outlet of the outdoor heat exchanger 23 is connected to the port b of the four-way valve 22 by the refrigerant pipe 62, and the other refrigerant inlet/outlet is connected to the liquid side closing valve 25 and the outdoor unit liquid pipe 63.
- the outdoor heat exchanger 23 functions as a condenser during cooling and functions as an evaporator during heating operation by switching the four-way valve 22 described later.
- the first expansion valve 24 and the second expansion valve 28 during heating operation are electronic expansion valves driven by a pulse motor (not shown). Specifically, the opening degree is adjusted by the number of pulses applied to the pulse motor. The opening degree of the first expansion valve 24 is adjusted so that SC reaches a predetermined target value. In addition, the opening degree of the second expansion valve 28 is adjusted so that the discharge temperature, which is the temperature of the refrigerant discharged from the compressor 21, reaches a predetermined target temperature during the heating operation.
- the outdoor fan 27 is made of a resin material and is arranged near the outdoor heat exchanger 23.
- the outdoor fan 27 is connected at its center to a rotating shaft of a fan motor (not shown).
- the outdoor fan 27 rotates as the fan motor rotates.
- the outside air is taken into the inside of the outdoor unit 2 from the suction port (not shown) of the outdoor unit 2, and the outside air that has exchanged heat with the refrigerant in the outdoor heat exchanger 23 is discharged from the outlet (not shown) of the outdoor unit 2 to the outside. Discharge to the outside of machine 2.
- the outdoor unit 2 is provided with various sensors.
- a discharge pressure sensor 71 for detecting the pressure of the refrigerant discharged from the compressor 21 and a temperature of the refrigerant discharged from the compressor 21 (the above-mentioned discharge temperature) are detected in the discharge pipe 61.
- the discharge temperature sensor 73 is provided.
- a suction pressure sensor 72 for detecting the pressure of the refrigerant sucked into the compressor 21 and a suction temperature sensor 74 for detecting the temperature of the refrigerant sucked into the compressor 21 are connected to the outdoor unit liquid pipe 63.
- a heat exchange temperature sensor 75 for detecting the outdoor heat exchange temperature, which is the temperature of the outdoor heat exchanger 23, is provided at a substantially middle portion of a refrigerant path (not shown) of the outdoor heat exchanger 23.
- An outdoor air temperature sensor 76 that detects the temperature of the outdoor air flowing into the outdoor unit 2, that is, the outdoor air temperature is provided near the suction port (not shown) of the outdoor unit 2.
- the outdoor unit 2 is provided with the outdoor unit control means 200.
- the outdoor unit control means 200 is mounted on a control board stored in an electric component box (not shown) of the outdoor unit 2.
- the outdoor unit control unit 200 includes a CPU 210, a storage unit 220, a communication unit 230, and a sensor input unit 240 (in this specification, the outdoor unit control unit 200 is simply referred to as the outdoor unit control unit 200. Sometimes called control means).
- the storage unit 220 is composed of a flash memory, and stores a control program of the outdoor unit 2, detection values corresponding to detection signals from various sensors, control states of the compressor 21, the outdoor fan 27, and the like. Although not shown, the storage unit 220 stores in advance a rotation speed table in which the rotation speed of the compressor 21 is determined according to the required capacity received from the indoor unit 3.
- the communication unit 230 is an interface that communicates with the indoor unit 3.
- the sensor input unit 240 takes in the detection results of various sensors of the outdoor unit 2 and outputs them to the CPU 210.
- the CPU 210 fetches the detection result of each sensor of the outdoor unit 2 described above via the sensor input unit 240. Further, the CPU 210 takes in the control signal transmitted from the indoor unit 3 via the communication unit 230. The CPU 210 controls the drive of the compressor 21 and the outdoor fan 27 based on the captured detection result, control signal, and the like. The CPU 210 also controls the switching of the four-way valve 22 based on the captured detection result and control signal. Furthermore, the CPU 210 performs opening adjustment of the first expansion valve 24 and the second expansion valve 28, opening/closing control of the injection expansion valve 29, and opening adjustment based on the captured detection result and control signal. The CPU 210 is provided with a liquid storage determination unit that determines whether or not the liquid refrigerant is stored in the medium pressure receiver 81. The liquid storage determination unit is provided in the medium pressure receiver 81, as will be described later in detail. When it is determined that the liquid refrigerant is stored, the injection expansion valve 29 is opened to inject the refrigerant to the intermediate pressure of the compressor 21.
- the indoor unit 3 includes an indoor heat exchanger 31, an indoor fan 32, a liquid pipe connecting portion 33 to which the other end of the liquid pipe 4 is connected, and a gas pipe connecting portion 34 to which the other end of the gas pipe 5 is connected. I have it.
- Each of these devices except the indoor fan 32 is connected to each other by respective refrigerant pipes described in detail below to form an indoor unit refrigerant circuit 10b forming a part of the refrigerant circuit 10.
- the indoor heat exchanger 31 is for exchanging heat between the indoor air taken into the indoor unit 3 from the suction port (not shown) of the indoor unit 3 by the rotation of the refrigerant and the indoor fan 32 described later.
- One of the refrigerant inlet/outlet ports of the indoor heat exchanger 31 is connected to the liquid pipe connecting portion 33 by the indoor unit liquid pipe 67.
- the other refrigerant inlet/outlet of the indoor heat exchanger 31 is connected to the gas pipe connecting portion 34 by an indoor unit gas pipe 68.
- the indoor heat exchanger 31 functions as an evaporator when the indoor unit 3 performs a cooling operation, and functions as a condenser when the indoor unit 3 performs a heating operation.
- the indoor fan 32 is made of a resin material and is arranged near the indoor heat exchanger 31.
- the indoor fan 32 is rotated by a fan motor (not shown) to take in indoor air into the interior of the indoor unit 3 from an intake port (not shown) of the indoor unit 3 and to exchange the indoor air with the refrigerant in the indoor heat exchanger 31 into the indoor air.
- the air is blown out into the room from an air outlet (not shown) of the machine 3.
- the indoor unit 3 is provided with various sensors.
- the indoor unit liquid pipe 67 is provided with a liquid side temperature sensor 77a that detects the temperature of the refrigerant flowing into or out of the indoor heat exchanger 31.
- the indoor unit gas pipe 68 is provided with a gas side temperature sensor 78 that detects the temperature of the refrigerant flowing out from the indoor heat exchanger 31 or flowing into the indoor heat exchanger 31.
- the CPU 210 causes the four-way valve 22 to be in a state shown by a solid line as shown in FIG. 1A, that is, the port a and the port d of the four-way valve 22 communicate with each other and the port b and the port b. Switch so that c communicates.
- the refrigerant circulates in the refrigerant circuit 10 in the direction indicated by the solid line arrow, and the outdoor heat exchanger 23 functions as an evaporator, and the indoor heat exchanger 31 functions as a condenser.
- the high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 61 and flows into the four-way valve 22.
- the refrigerant flowing into the port a of the four-way valve 22 flows from the port d of the four-way valve 22 through the outdoor unit gas pipe 64, and then flows into the gas pipe 5 via the gas side closing valve 26.
- the refrigerant flowing through the gas pipe 5 flows into the indoor unit 3 via the gas pipe connecting portion 34.
- the refrigerant that has flowed into the indoor unit 3 flows through the indoor unit gas pipe 68 and flows into the indoor heat exchanger 31, where it exchanges heat with the indoor air taken into the indoor unit 3 by the rotation of the indoor fan 32 and condenses. To do.
- the indoor heat exchanger 31 functions as a condenser, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 is blown out into the room from an outlet (not shown), so that the indoor unit 3 is installed.
- the heated room is heated.
- the refrigerant flowing out of the indoor heat exchanger 31 flows through the indoor unit liquid pipe 67 and then flows into the liquid pipe 4 via the liquid pipe connection portion 33.
- the refrigerant flowing through the liquid pipe 4 and flowing into the outdoor unit 2 through the liquid side closing valve 25 flows through the outdoor unit liquid pipe 63 and passes through the first expansion valve 24, the intermediate pressure receiver 81, and the second expansion valve 28.
- the opening degree of the first expansion valve 24 is set so that the degree of supercooling (SC) of the refrigerant after the indoor heat exchanger 31 flows out becomes a predetermined target value.
- the opening degree of 28 is adjusted so that the discharge temperature of the compressor 21 reaches a predetermined target value, or the suction superheat degree (intake SH) of the refrigerant sucked into the compressor 21 reaches a predetermined target value. Adjusted to be.
- the refrigerant that has passed through the first expansion valve 24, the intermediate pressure receiver 81, and the second expansion valve 28 and has flowed into the outdoor heat exchanger 23 exchanges heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 27. To evaporate.
- the refrigerant flowing from the outdoor heat exchanger 23 to the refrigerant pipe 62 flows through the ports b and c of the four-way valve 22 and the suction pipe 66, is sucked into the compressor 21 and is compressed again.
- the basic refrigerant circuit 11 will be described with reference to FIGS. 2 and 3.
- the point A is between the compressor 21 and the condenser (corresponding to the indoor heat exchanger 31 during the heating operation.
- the condenser 31 the point B.
- the expansion valve 28 the point C is between the expansion valve 28 and the evaporator (the outdoor heat exchanger 23 during the heating operation).
- the point D indicates between the evaporator 23 and the compressor 21 (the same applies hereinafter).
- the state of the refrigerant from point A to point D, or between each point, is as follows, as shown in FIG. (1)
- the refrigerant (between points D and A) in the compression process in the compressor 21 is compressed, and both the pressure (vertical axis) and the temperature rise to become high-temperature and high-pressure superheated vapor (by heat exchange with ambient air). It becomes easy to condense).
- the refrigerant (point A) discharged from the compressor 21 is a superheated high-pressure gas-phase refrigerant.
- the refrigerant (between points A and B) in the condensation process in the condenser 31 exchanges heat (radiates heat) with the ambient air, so that the pressure remains constant and superheated steam, saturated steam, wet steam, saturated liquid After each of the above states, it becomes high-pressure supercooled liquid.
- the refrigerant (point B) flowing out from the condenser 31 is a high-pressure liquid-phase refrigerant in a supercooled state.
- the refrigerant (between points B and C) in the expansion process in the expansion valve 28 expands and both the pressure (vertical axis) and the temperature decrease to become wet vapor (it is easy to evaporate by heat exchange with ambient air). State).
- the refrigerant in the evaporation process in the evaporator 23 exchanges heat with the ambient air (endothermic heat), so that the pressure of the refrigerant remains constant and passes through the states of wet steam and saturated steam. It becomes low pressure superheated steam.
- the refrigerant (point D) flowing out from the evaporator 23 is a superheated low-pressure gas-phase refrigerant.
- the control method of the compressor 21, the indoor fan 32, the expansion valve 28, and the outdoor fan 27, which are the objects to be controlled in this basic refrigerant circuit 11, is as follows.
- the indoor fan 32 is controlled according to the difference between the room temperature and the set temperature during heating operation (when the condenser is the indoor heat exchanger 31) and during cooling operation (when the condenser is the outdoor heat exchanger 23), or by the user. It is set to obtain the desired air volume.
- the expansion valve 28 is controlled so that the temperature of the point A (discharge temperature) reaches a target value (discharge temperature control), or a control amount (pulse) determined in advance according to the amount of change in the rotation speed of the compressor 21.
- the expansion valve 28 is controlled by a control for adjusting the opening degree (rotational speed pulse control).
- the discharge temperature control is a feedback control that adjusts the opening degree after a disturbance such as the room temperature or the outside air temperature appears in the change of the discharge temperature, whereas the rotation speed pulse control circulates from the change amount of the rotation speed. This is feedforward control in which the amount of change in the amount is predicted and the expansion valve 28 is adjusted in advance so as to have an appropriate opening.
- the outdoor fan 27 is controlled based on the rotation speed of the compressor 21 both during heating operation (when the evaporator is on the heat source side) and during cooling operation (when the evaporator is on the use side).
- the basic operational restrictions in the refrigerant circuit 11 are as follows.
- the reason is that when the two-phase refrigerant flows into the expansion valve 28, there arises inconveniences such as generation of refrigerant flow noise and deterioration of controllability.
- the refrigerant circuit 12 having the injection circuit 65 will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, in the refrigerant circuit 12 having the injection circuit 65, a part of the refrigerant after flowing out from the condenser 31 is caused to flow into the intermediate pressure of the compressor 21.
- the injection circuit 65 includes an injection expansion valve 29 that adjusts the amount of refrigerant injected into the compressor 21, and an inter-refrigerant heat exchanger 82 (SC heat exchanger) to increase the dryness of the injected refrigerant.
- SC heat exchanger inter-refrigerant heat exchanger
- points E to G are added to the reference points of the refrigerant circuit 12 in addition to points A to D, and the point E is the outdoor unit liquid pipe 63 side flow path outlet of the inter-refrigerant heat exchanger 82.
- the purpose of the injection circuit 65 is to increase the refrigerant circulation amount of the condenser 31 (to increase the heating capacity during low outside air ( ⁇ 20 to ⁇ 30° C.) heating operation, etc.) and to lower the discharge temperature of the compressor 21. (By setting the evaporation temperature lower than the outside air temperature during low outside air heating operation, the temperature of the compressor 21 does not become an abnormal temperature even if the pressure difference between the high pressure (condensing pressure) and the low pressure (evaporating pressure) becomes large. It is that).
- the state of the refrigerant in the refrigerant circuit 12 is as shown in FIG. 5, but the points different from the refrigerant circuit 11 are as follows. (1) Between points D and A in the compression process of the compressor 21, a part of the refrigerant in the condensation process flows into the intermediate pressure of the compressor 21 in a two-phase state via the injection circuit 65, and The temperature of the refrigerant compressed in 21 decreases during the compression, and the discharge temperature at point A decreases compared to the case where the refrigerant is not circulated in the injection circuit 65. (2) The refrigerant passes between points A and B in the condensation process and becomes a liquid phase state, and then flows between points F and G of the injection circuit 65 between points B and E and the heat exchanger between refrigerants.
- the heat is exchanged and supercooled by 82.
- the refrigerant flowing between B and E is heat-exchanged by the inter-refrigerant heat exchanger 82 to increase the dryness, and is injected from the point G to the points D to A of the compression process.
- the control method of the expansion valve 28 and the injection expansion valve 29, which are characteristic objects to be controlled in the refrigerant circuit 12, are as follows.
- the expansion valve 28 controls the temperature (discharge temperature) of the point A to be a target value (discharge temperature control), and is predetermined according to the amount of change in the rotation speed of the compressor 21.
- Control rotation speed pulse control
- suction SH temperature at point D-temperature at point C
- suction SH control a target value
- Control rotation speed pulse control
- the injection expansion valve 29 is closed when injection is not performed.
- control is performed so that the temperature at point A (discharge temperature) or discharge SH reaches a target value (discharge temperature control or discharge SH control).
- the refrigerant circuit 13 including the intermediate pressure receiver 81 will be described with reference to FIGS. 6 and 7. As shown in FIG. 6, the reference points of the refrigerant circuit 13 are points A to D as in the basic refrigerant circuit 11.
- the purpose of the medium pressure receiver 81 is to adjust the amount of refrigerant to an appropriate amount, regardless of the size of the indoor unit 3 to be connected. This corresponds to the fact that the amount of refrigerant required for the refrigerant circuit 13 differs depending on the size of the indoor heat exchanger 31 and the lengths of pipes (internal volume) at various places.
- the required amount of refrigerant is different means that the amount of refrigerant required for efficient and reliable operation (appropriate suction SH, SC) is the size of the indoor heat exchanger and the length of the connecting pipe. This means that there is a difference in volume due to such a difference, and the inside of the intermediate pressure receiver 81 is adjusted by letting the refrigerant inside the refrigerant circuit 13 flow in and out.
- the refrigerant circuit 13 having the medium pressure receiver 81 includes the medium pressure receiver 81 between the condenser 31 and the evaporator 23, and the first expansion valve 24 and the first expansion valve 24 are provided on the upstream side and the downstream side of the medium pressure receiver 81, respectively.
- a second expansion valve 28 is provided.
- the state of the refrigerant in the refrigerant circuit 13 is substantially the same as that of the basic refrigerant circuit 11, as shown in FIG. 7.
- the control method of the first expansion valve 24 and the second expansion valve 28, which are characteristic control objects in the refrigerant circuit 13, are as follows.
- SC control
- the refrigerant circuit 10 includes both the injection circuit 65 and the intermediate pressure receiver 81 described above.
- FIG. 8 shows the refrigerant circuit 10 by simplifying FIGS. 1A and 1B.
- the first expansion is performed before the injection circuit 65 branches (upstream side). This is a mode in which the valve 24 and the intermediate pressure receiver 81 are provided.
- the expansion valve 28 in FIG. 4 becomes the second expansion valve 28.
- a point H is added in addition to the points A to D and points E to G, and the point H is between the first expansion valve 24 and the intermediate pressure receiver 81. Point to.
- the state of the refrigerant in the refrigerant circuit 10 is as shown in FIG. 9, but the points different from the refrigerant circuit 12 are as follows. (1) The pressure of the refrigerant decreases after passing through points A and B in the condensation process through the first expansion valve 24 between points B and H, and then between points H and E at point F of the injection circuit 65. Heat is exchanged between G and G by the heat exchanger 82 between refrigerants. (2) The pressure of the refrigerant flowing into the injection circuit 65 branched from the point H between the points A to E decreases via the injection expansion valve 29 between the points H to F, and then the point B between the points F and G. To E and heat is exchanged by the heat exchanger 82 between refrigerants to increase the dryness, and injection is performed from the point G to the points D to A in the compression process.
- FIG. 11A generally shows the relationship between the difference between the condensation temperature and the ambient temperature (hereinafter referred to as ⁇ t) and the SC value.
- ⁇ t the difference between the condensation temperature and the ambient temperature
- FIG. 11B in the range below SCmin (1 to 2 deg), regardless of the value of ⁇ t, the refrigerant becomes two-phase due to the pressure loss before flowing from the condenser 23 to the second expansion valve 28. , Refrigerant flow noise (noise) may occur.
- the refrigerant flowing through the condenser is cooled by the air at ambient temperature, so the SC limit value is ⁇ t. Therefore, when the target SC value is set in the region of SC> ⁇ t (X region), it becomes impossible to reach the target SC value. Therefore, the condition for setting the target SC is the region (Y region and Z region) of “SCmin ⁇ target SC ⁇ t”.
- the liquid single-phase region where a large amount of liquid refrigerant is accumulated does not contribute to heat exchange with air because the refrigerant does not change in latent heat. That is, in the region ( ⁇ t* ⁇ SC ⁇ t), the liquid single-phase region that does not contribute to heat exchange with air increases, so that the heat exchange efficiency of the heat exchanger decreases. Therefore, a preferable condition for setting the target SC is a region (Z region) of “SCmin ⁇ target SC ⁇ t* ⁇ ”.
- the SC value is the one that gives the best performance (for example, COP).
- FIG. 11B shows a case where the target SC value is fixed, that is, a fixed value, in the conventional example.
- the thick line in the figure is the target SC value SCt (fixed).
- the liquid refrigerant accumulates in the condenser 23, and the liquid single-phase region that does not contribute to heat exchange with the air increases, and the heat exchange efficiency decreases.
- the condensation temperature is higher than the ambient temperature, a large amount of the liquid refrigerant is stored in the condenser 23, but the refrigerant flows into the intermediate pressure receiver 81 by increasing the opening degree of the second expansion valve 28.
- the evaporator-side expansion valve 24 located on the downstream side of the intermediate pressure receiver 81 does not depend on the amount of the liquid refrigerant flowing out from the second expansion valve 28, and the suction superheat degree (suction SH) of the refrigerant sucked into the compressor 21. Is adjusted to a predetermined target value. Therefore, when the target SC value is fixed, the medium pressure receiver 81 needs to have a sufficient volume to store the refrigerant flowing out from the second expansion valve 28. That is, it leads to an increase in the size of the air conditioner.
- FIG. 11C shows a case where the target SC value is changed in multiple stages in the air conditioner of the embodiment.
- the thick line in the figure is the target SC value SCt (change).
- the target SC value is switched to four levels (first target SC value, second target SC value, third target SC value, fourth target SC value) according to ⁇ t.
- the first target SC value smaller than the target SC value (fixed) in FIG. 11B is switched.
- the target SC value SCt corresponding to ⁇ t is stored in the storage unit 220 in advance so that the minimum SC value (for example, 2 deg) required for controllability and noise countermeasures becomes the target SC value. deep.
- the minimum SC value required for controllability and noise control is two-phased due to pressure loss until the refrigerant flows from the condenser 23 to the second expansion valve 28, and refrigerant flow noise (noise) does not occur.
- the minimum SC value shall be determined by conducting a test beforehand.
- the target SC value SCt corresponding to ⁇ t is stored in advance in the storage unit 220 so that the SC value that maximizes the performance (for example, COP) as the air conditioner becomes the target SC value (for example, 6 deg).
- COP is a value obtained by dividing the enthalpy difference in the condensation process or the evaporation process by the enthalpy difference in the compression process. That is, if the enthalpy difference in the condensation process or the evaporation process can be increased without increasing the enthalpy difference in the compression process, the COP is improved.
- the larger the target SC value the larger the enthalpy difference in the condensation process. That is, the performance is improved by increasing the target SC value as much as possible. However, if the target SC value is too large ( ⁇ t* ⁇ SC), it takes time for the SC value to reach the target SC.
- the opening degree of the expansion valve 28 decreases until the SC value reaches the target SC value, the density of the refrigerant flowing in the evaporator decreases, and the reliability of the compressor 21 decreases. Therefore, it is possible to select the SC value that has the best performance (for example, COP) as the air conditioner and that can secure the reliability of the compressor 21, and set it as the target SC value.
- SC value that has the best performance (for example, COP) as the air conditioner and that can secure the reliability of the compressor 21, and set it as the target SC value.
- the processing executed by the CPU 210 of the outdoor unit control means 200 when performing the cooling operation will be described using the flowchart shown in FIG.
- the first expansion valve 24 serves as the upstream expansion valve and the second expansion valve serves as the downstream expansion valve.
- FIG. 10 shows the flow of processing when the CPU 210 performs the cooling operation, and ST represents a step and the number following this represents a step number.
- FIG. 10 mainly describes the processes related to the present disclosure, and processes other than this, for example, air control such as control of the refrigerant circuit 10 corresponding to operating conditions such as set temperature and air volume instructed by the user.
- air control such as control of the refrigerant circuit 10 corresponding to operating conditions such as set temperature and air volume instructed by the user.
- the description of the general processing related to the harmony machine 1 is omitted.
- the CPU 210 controls the activation of the compressor 21, the upstream expansion valve (second expansion valve 28), and the downstream expansion valve (first expansion valve 24) (ST101).
- the startup control of the compressor 21 is a control in which the rotation speed is increased stepwise for the purpose of suppressing the amount of oil discharged from the compressor 21.
- the initial pulse corresponding to the outside air temperature determined in advance in a test or the like is stored in the storage unit 220, and the opening degree of each of the initial pulses is set by the initial pulse. It is a fixed control.
- the CPU 210 determines whether or not a termination condition for activation control (for example, 10 minutes have elapsed from the start of activation control) is satisfied (ST102), and if the termination condition is satisfied (ST102-YES), compression is performed.
- the machine 21, the second expansion valve 28, and the first expansion valve 24 are switched to normal control (ST103). If the ending condition is not satisfied (ST102-NO), the process returns to ST102.
- the compressor 21 is controlled to the rotation speed corresponding to the request code
- the second expansion valve 28 is SC control
- the first expansion valve 24 is suction SH control.
- the request code is a signal sent from the indoor unit 3 via the communication unit of the outdoor unit control means 200. For example, when the indoor temperature, which is the detection value of the room temperature sensor 79, greatly exceeds the set temperature of the air conditioner during the cooling operation, the request code increases the rotation speed of the compressor 21 in accordance with the difference. The value to be set is set.
- the CPU 210 sets "2" to the count value n of the counter (not shown) after the processing of ST103.
- the counter is provided in the CPU 210.
- the count value n is used for switching a plurality of target SC values described later.
- four target values SCt (first target SC value, second target SC value, third target SC value, fourth target SC value) are stored in the storage unit 220. ..
- the count value n has a number of values corresponding to the number of target values. Therefore, the maximum value nmax of the count value n is “4” and the minimum value nmin is “1”.
- the count value n of the counter is set to "2" in ST103, it may be another value.
- the CPU 210 determines whether or not ⁇ t* ⁇ nth target SC value (ST105). Since the count value n is set to "2" in ST103, " ⁇ t* ⁇ second target SC value" is the determination condition here. The coefficient ⁇ will be described later.
- the CPU 210 determines whether n is the minimum value nmin (ST106). When n is the minimum value nmin (ST106-NO), the process returns to the determination of ST105. When n is not the minimum value nmin (ST106-YES), the (n-1)th target SC value is set as the target SC value (ST107).
- the first target SC value is set as the target SC value. Then, it is determined whether or not a predetermined time (for example, 10 seconds) has passed (ST108), and when the predetermined time has passed (ST108-YES), the process returns to the determination of ST105. When the predetermined time has not elapsed (ST108-NO), the determination of ST108 is repeated.
- the predetermined time is a control interval of this control. After changing the target SC value SCt, the difference ⁇ t changes due to changes in the rotation speed of the compressor 21 and the like. In order to change the target SC value SCt corresponding to such a case, for example, the predetermined time is set to 10 seconds so that the main control can always be performed.
- the CPU 210 determines whether n is the maximum value nmax (ST109). When n is the maximum value nmax (ST109-NO), the process returns to the determination of ST105. If n is not the maximum value nmax (ST109-YES), the target SC value is set to the (n+1)th target SC value (ST110). Here, the third target SC value is set as the target SC value. Then, the process proceeds to ST108.
- ST108 it is determined whether or not a predetermined time (for example, 30 seconds) has elapsed (ST108), and when the predetermined time has elapsed (ST108-YES), the process returns to the determination of ST105.
- a predetermined time for example, 30 seconds
- ST108-NO the determination of ST108 is repeated.
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Abstract
An air conditioner (1) comprises: a refrigerant circuit (10, 13) in which a refrigerant flows through, in order, a compressor (21), a condenser (23), a second expansion valve (28), a medium pressure receiver (81), a first expansion valve (24), and an evaporator (31) connected by refrigerant piping; and a control means (200) that controls the second expansion valve (28) and the first expansion valve (24). The control means (200) performs SC control to control the degree that a condensing side expansion valve is opened so that the SC value, which is the difference between the condensing temperature and the outlet temperature, is a target value, and changes the target value SCt according to the difference Δt between the condensing temperature and the ambient temperature in the condenser.
Description
本開示は、空気調和機に関する。
The present disclosure relates to an air conditioner.
空気調和機の室外機において、凝縮器と蒸発器の間に中圧レシーバを設け、その前後に膨張弁を備えたものがある。この時の2つの膨張弁の制御としては、暖房運転時の上流側(凝縮側)膨張弁をSC(サブクール:過冷却度)制御、暖房運転時の下流側(蒸発側)膨張弁を吸入SH(吸入スーパーヒート:吸入過熱度)制御又は吐出温度制御としている。
Some outdoor units of air conditioners have a medium-pressure receiver between the condenser and the evaporator, and expansion valves before and after the medium-pressure receiver. At this time, the two expansion valves are controlled by SC (subcool: supercooling) control of the upstream (condensing side) expansion valve during the heating operation and intake of the downstream (evaporation side) expansion valve during the heating operation SH. (Suction superheat: superheat of suction) control or discharge temperature control.
しかしながら、凝縮側膨張弁のSC制御において、SCが予め定めた目標値となるように開度制御することから、SCが目標値に到達しにくい条件(例えば、冷媒の循環量が少ない運転時や、高外気温下における冷房運転時)では、凝縮側膨張弁の開度が過度に小さくなる。
However, in the SC control of the condensation side expansion valve, since the opening degree is controlled so that SC reaches a predetermined target value, it is difficult for SC to reach the target value (for example, during operation when the circulation amount of the refrigerant is small or During the cooling operation under high outside temperature), the opening degree of the condensation side expansion valve becomes excessively small.
そうすると、凝縮器から冷媒が流出しなくなるため、凝縮器の内部に液冷媒が溜まる。凝縮器の内部に液冷媒が溜まると、中圧レシーバ内の液冷媒が減ることによって蒸発器に流れる冷媒の量が減り、蒸発器側膨張弁の開度を大きくしても圧縮機に吸入される冷媒の乾き度が下降しないなど、蒸発側膨張弁が機能しなくなる。その結果、圧縮機の信頼性低下、保護動作発生による回転数低下が発生するという問題が発生する。
▽ Then, the refrigerant does not flow out from the condenser, so the liquid refrigerant accumulates inside the condenser. When liquid refrigerant accumulates inside the condenser, the amount of liquid refrigerant in the medium-pressure receiver decreases, and the amount of refrigerant flowing to the evaporator decreases, so even if the opening of the evaporator-side expansion valve is increased, it is drawn into the compressor. The evaporating side expansion valve does not function because the dryness of the refrigerant is not lowered. As a result, there arise problems that the reliability of the compressor is reduced and the rotation speed is reduced due to the occurrence of the protection operation.
そこで、本開示では、中圧レシーバを備える空気調和機において、圧縮機の信頼性低下を抑制することができる技術を提案する。
Therefore, in the present disclosure, in an air conditioner including a medium-pressure receiver, a technology that can suppress deterioration in reliability of the compressor is proposed.
本開示の空気調和機は、冷媒回路と、制御手段と、凝縮温度センサと、凝縮器出口温度センサと、凝縮器周囲温度センサとを有する。冷媒回路では、冷媒が、圧縮機、凝縮器、凝縮側膨張弁、中圧レシーバ、蒸発側膨張弁、蒸発器の順に流れるように冷媒配管で接続されている。制御手段は、凝縮側膨張弁及び蒸発側膨張弁を制御する。凝縮温度センサは、凝縮温度を検出する。凝縮器出口温度センサは、凝縮器から流出した冷媒の温度である凝縮器出口温度を検出する。凝縮器周囲温度センサは、凝縮器の周囲温度を検出する。そして、制御手段は、凝縮温度と凝縮器出口温度の差であるSC値が目標値SCtとなるように凝縮側膨張弁の開度を制御するSC制御を行い、凝縮温度と周囲温度の差Δtに応じて、目標値SCtを変更する。
The air conditioner of the present disclosure has a refrigerant circuit, a control unit, a condensation temperature sensor, a condenser outlet temperature sensor, and a condenser ambient temperature sensor. In the refrigerant circuit, a refrigerant pipe is connected so that the refrigerant flows in the order of the compressor, the condenser, the condensation side expansion valve, the intermediate pressure receiver, the evaporation side expansion valve, and the evaporator. The control means controls the condensation side expansion valve and the evaporation side expansion valve. The condensation temperature sensor detects the condensation temperature. The condenser outlet temperature sensor detects the condenser outlet temperature which is the temperature of the refrigerant flowing out from the condenser. The condenser ambient temperature sensor detects the ambient temperature of the condenser. Then, the control means performs SC control for controlling the opening degree of the condensation side expansion valve so that the SC value, which is the difference between the condensation temperature and the condenser outlet temperature, becomes the target value SCt, and the difference Δt between the condensation temperature and the ambient temperature. The target value SCt is changed accordingly.
本開示によれば、中圧レシーバを備える空気調和機において、圧縮機の信頼性低下を抑制することができる。
According to the present disclosure, in an air conditioner including a medium pressure receiver, it is possible to suppress deterioration in reliability of the compressor.
以下、本開示の実施形態を、添付図面に基づいて詳細に説明する。なお、本開示は以下の実施形態に限定されることはなく、本開示の主旨を逸脱しない範囲で種々変形することが可能である。
Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The present disclosure is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present disclosure.
<冷媒回路の構成>
まず、図1Aを参照して、室外機2を含む空気調和機1の冷媒回路について説明する。図1Aに示すように、本実施形態における空気調和機1は、屋外に設置される室外機2と、室内に設置され、室外機2に液管4及びガス管5で接続された室内機3を備えている。詳細には、室外機2の液側閉鎖弁25と室内機3の液管接続部33が液管4で接続されている。また、室外機2のガス側閉鎖弁26と室内機3のガス管接続部34がガス管5で接続されている。以上により、空気調和機1の冷媒回路10が形成される。 <Structure of refrigerant circuit>
First, the refrigerant circuit of theair conditioner 1 including the outdoor unit 2 will be described with reference to FIG. 1A. As shown in FIG. 1A, an air conditioner 1 according to this embodiment includes an outdoor unit 2 installed outdoors and an indoor unit 3 installed indoors and connected to the outdoor unit 2 by a liquid pipe 4 and a gas pipe 5. Equipped with. Specifically, the liquid-side shutoff valve 25 of the outdoor unit 2 and the liquid pipe connecting portion 33 of the indoor unit 3 are connected by the liquid pipe 4. Further, the gas side closing valve 26 of the outdoor unit 2 and the gas pipe connecting portion 34 of the indoor unit 3 are connected by the gas pipe 5. As described above, the refrigerant circuit 10 of the air conditioner 1 is formed.
まず、図1Aを参照して、室外機2を含む空気調和機1の冷媒回路について説明する。図1Aに示すように、本実施形態における空気調和機1は、屋外に設置される室外機2と、室内に設置され、室外機2に液管4及びガス管5で接続された室内機3を備えている。詳細には、室外機2の液側閉鎖弁25と室内機3の液管接続部33が液管4で接続されている。また、室外機2のガス側閉鎖弁26と室内機3のガス管接続部34がガス管5で接続されている。以上により、空気調和機1の冷媒回路10が形成される。 <Structure of refrigerant circuit>
First, the refrigerant circuit of the
<<室外機の冷媒回路>>
まずは、室外機2について説明する。室外機2は、圧縮機21と、四方弁22と、室外熱交換器23と、暖房運転時における第1膨張弁24と、液管4が接続された液側閉鎖弁25と、ガス管5が接続されたガス側閉鎖弁26と、室外ファン27と、暖房運転時における第2膨張弁28と、インジェクション膨張弁29と、中圧レシーバ81と、冷媒間熱交換器82を備えている。そして、室外ファン27を除くこれら各装置が後述する各冷媒配管で相互に接続されて、冷媒回路10の一部をなす室外機冷媒回路10aを形成している。なお、圧縮機21の冷媒吸入側には、アキュムレータ(不図示)が設けられてもよい。また、本明細書では「インジェクション」を「INJ」と表記することがある。 <<Refrigerant circuit of outdoor unit>>
First, theoutdoor unit 2 will be described. The outdoor unit 2 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, a first expansion valve 24 during heating operation, a liquid side closing valve 25 to which the liquid pipe 4 is connected, and a gas pipe 5 Is connected to the gas side closing valve 26, the outdoor fan 27, the second expansion valve 28 during the heating operation, the injection expansion valve 29, the intermediate pressure receiver 81, and the heat exchanger 82 between refrigerants. The respective devices except the outdoor fan 27 are connected to each other by respective refrigerant pipes described later to form an outdoor unit refrigerant circuit 10a forming a part of the refrigerant circuit 10. An accumulator (not shown) may be provided on the refrigerant suction side of the compressor 21. Moreover, in this specification, "injection" may be described as "INJ."
まずは、室外機2について説明する。室外機2は、圧縮機21と、四方弁22と、室外熱交換器23と、暖房運転時における第1膨張弁24と、液管4が接続された液側閉鎖弁25と、ガス管5が接続されたガス側閉鎖弁26と、室外ファン27と、暖房運転時における第2膨張弁28と、インジェクション膨張弁29と、中圧レシーバ81と、冷媒間熱交換器82を備えている。そして、室外ファン27を除くこれら各装置が後述する各冷媒配管で相互に接続されて、冷媒回路10の一部をなす室外機冷媒回路10aを形成している。なお、圧縮機21の冷媒吸入側には、アキュムレータ(不図示)が設けられてもよい。また、本明細書では「インジェクション」を「INJ」と表記することがある。 <<Refrigerant circuit of outdoor unit>>
First, the
圧縮機21は、図示しないインバータにより回転数が制御されることで、運転容量を変えることができる容量可変型圧縮機である。圧縮機21の冷媒吐出側は、四方弁22のポートaと吐出管61で接続されている。また、圧縮機21の冷媒吸入側は、四方弁22のポートcと吸入管66で接続されている。
The compressor 21 is a variable capacity compressor whose operating capacity can be changed by controlling the rotation speed by an inverter (not shown). The refrigerant discharge side of the compressor 21 is connected to the port a of the four-way valve 22 by a discharge pipe 61. The refrigerant suction side of the compressor 21 is connected to the port c of the four-way valve 22 by a suction pipe 66.
中圧レシーバ81は、液側閉鎖弁25と室外熱交換器23との間の室外機液管63に、第1膨張弁24と第2膨張弁28に挟まれて設けられている。中圧レシーバ81は、大小様々な室内機3が接続されても、適切な冷媒量に調整するためのものである。中圧レシーバ81の下流側ではインジェクション配管(インジェクション回路ともいう)65が分岐しており、インジェクション配管65は、インジェクション膨張弁29を介して圧縮機21内部の図示しないシリンダの中間部に接続されている。インジェクション配管65は、凝縮器(暖房運転時には室内熱交換器31)の冷媒循環量を増やしたり、圧縮機21の吐出温度を下げたりするため、圧縮機21に冷媒をインジェクションするものである。インジェクション配管65の途中には、インジェクション配管65を流れる冷媒と室外機液管63を流れる冷媒との間で熱交換を行う冷媒間熱交換器82が設けられている。
The intermediate pressure receiver 81 is provided in the outdoor unit liquid pipe 63 between the liquid side closing valve 25 and the outdoor heat exchanger 23, sandwiched between the first expansion valve 24 and the second expansion valve 28. The medium pressure receiver 81 is for adjusting the amount of refrigerant to an appropriate amount, even if the indoor units 3 of various sizes are connected. An injection pipe (also referred to as an injection circuit) 65 is branched on the downstream side of the intermediate pressure receiver 81, and the injection pipe 65 is connected to an intermediate portion of a cylinder (not shown) inside the compressor 21 via an injection expansion valve 29. There is. The injection pipe 65 is for injecting the refrigerant into the compressor 21 in order to increase the refrigerant circulation amount of the condenser (the indoor heat exchanger 31 during the heating operation) or lower the discharge temperature of the compressor 21. An inter-refrigerant heat exchanger 82 that exchanges heat between the refrigerant flowing through the injection pipe 65 and the refrigerant flowing through the outdoor unit liquid pipe 63 is provided in the middle of the injection pipe 65.
インジェクション配管65、インジェクション膨張弁29を含む一連の回路をインジェクション回路という(なお、本明細書では、インジェクション配管65で代表させてインジェクション回路ということがある。また、ここで示すインジェクション回路は一例であって、他の態様であってもよい)。インジェクション膨張弁29は、全閉可能であって、インジェクション配管65の開閉手段として設けられ、圧縮機21の吐出温度又は吐出SHを制御する。
A series of circuits including the injection pipe 65 and the injection expansion valve 29 is referred to as an injection circuit (in this specification, the injection pipe 65 is a representative example of an injection circuit. The injection circuit shown here is an example. And other modes may be used). The injection expansion valve 29 can be fully closed, is provided as an opening/closing means for the injection pipe 65, and controls the discharge temperature or the discharge SH of the compressor 21.
四方弁22は、冷媒の流れる方向を切り替えるための弁であり、a、b、c、dの4つのポートを備えている。ポートaは、上述したように圧縮機21の冷媒吐出側と吐出管61で接続されている。ポートbは、室外熱交換器23の一方の冷媒出入口と冷媒配管62で接続されている。ポートcは、上述したように圧縮機21の冷媒吸入側と吸入管66で接続されている。そして、ポートdは、ガス側閉鎖弁26と室外機ガス管64で接続されている。なお、四方弁22が、本開示の流路切替手段である。
The four-way valve 22 is a valve for switching the flowing direction of the refrigerant, and has four ports a, b, c, d. The port a is connected to the refrigerant discharge side of the compressor 21 by the discharge pipe 61 as described above. The port b is connected to one refrigerant inlet/outlet of the outdoor heat exchanger 23 by a refrigerant pipe 62. The port c is connected to the refrigerant suction side of the compressor 21 by the suction pipe 66 as described above. The port d is connected to the gas side closing valve 26 by the outdoor unit gas pipe 64. The four-way valve 22 is the flow path switching unit of the present disclosure.
室外熱交換器23は、冷媒と、後述する室外ファン27の回転により室外機2の内部に取り込まれた外気を熱交換させるものである。室外熱交換器23の一方の冷媒出入口は、上述したように四方弁22のポートbと冷媒配管62で接続され、他方の冷媒出入口は液側閉鎖弁25と室外機液管63で接続されている。室外熱交換器23は、後述する四方弁22の切替えによって、冷房時は凝縮器として機能し、暖房運転時は蒸発器として機能する。
The outdoor heat exchanger 23 is for exchanging heat between the refrigerant and the outside air taken into the outdoor unit 2 by the rotation of an outdoor fan 27 described later. As described above, one refrigerant inlet/outlet of the outdoor heat exchanger 23 is connected to the port b of the four-way valve 22 by the refrigerant pipe 62, and the other refrigerant inlet/outlet is connected to the liquid side closing valve 25 and the outdoor unit liquid pipe 63. There is. The outdoor heat exchanger 23 functions as a condenser during cooling and functions as an evaporator during heating operation by switching the four-way valve 22 described later.
暖房運転時における第1膨張弁24及び第2膨張弁28は、図示しないパルスモータにより駆動される電子膨張弁である。具体的には、パルスモータに加えられるパルス数によりその開度が調整される。第1膨張弁24は、SCが所定の目標値になるように、その開度が調整される。また、第2膨張弁28は、暖房運転時は圧縮機21から吐出される冷媒の温度である吐出温度が所定の目標温度となるように、その開度が調整される。
The first expansion valve 24 and the second expansion valve 28 during heating operation are electronic expansion valves driven by a pulse motor (not shown). Specifically, the opening degree is adjusted by the number of pulses applied to the pulse motor. The opening degree of the first expansion valve 24 is adjusted so that SC reaches a predetermined target value. In addition, the opening degree of the second expansion valve 28 is adjusted so that the discharge temperature, which is the temperature of the refrigerant discharged from the compressor 21, reaches a predetermined target temperature during the heating operation.
室外ファン27は樹脂材で形成されており、室外熱交換器23の近傍に配置されている。室外ファン27は、その中心部が図示しないファンモータの回転軸に接続されている。ファンモータが回転することで室外ファン27が回転する。室外ファン27の回転によって、室外機2の図示しない吸込口から室外機2の内部へ外気を取り込み、室外熱交換器23において冷媒と熱交換した外気を、室外機2の図示しない吹出口から室外機2外部へ放出する。
The outdoor fan 27 is made of a resin material and is arranged near the outdoor heat exchanger 23. The outdoor fan 27 is connected at its center to a rotating shaft of a fan motor (not shown). The outdoor fan 27 rotates as the fan motor rotates. By the rotation of the outdoor fan 27, the outside air is taken into the inside of the outdoor unit 2 from the suction port (not shown) of the outdoor unit 2, and the outside air that has exchanged heat with the refrigerant in the outdoor heat exchanger 23 is discharged from the outlet (not shown) of the outdoor unit 2 to the outside. Discharge to the outside of machine 2.
以上説明した構成の他に、室外機2には各種のセンサが設けられている。図1Aに示すように、吐出管61には、圧縮機21から吐出される冷媒の圧力を検出する吐出圧力センサ71と、圧縮機21から吐出される冷媒の温度(上述した吐出温度)を検出する吐出温度センサ73が設けられている。吸入管66には、圧縮機21に吸入される冷媒の圧力を検出する吸入圧力センサ72と、圧縮機21に吸入される冷媒の温度を検出する吸入温度センサ74が、室外機液管63には、暖房運転時に第1膨張弁24から流出した冷媒の温度を検出する室外機液管温度センサ77bが設けられている。
Besides the configuration described above, the outdoor unit 2 is provided with various sensors. As shown in FIG. 1A, a discharge pressure sensor 71 for detecting the pressure of the refrigerant discharged from the compressor 21 and a temperature of the refrigerant discharged from the compressor 21 (the above-mentioned discharge temperature) are detected in the discharge pipe 61. The discharge temperature sensor 73 is provided. In the suction pipe 66, a suction pressure sensor 72 for detecting the pressure of the refrigerant sucked into the compressor 21 and a suction temperature sensor 74 for detecting the temperature of the refrigerant sucked into the compressor 21 are connected to the outdoor unit liquid pipe 63. Is provided with an outdoor unit liquid pipe temperature sensor 77b for detecting the temperature of the refrigerant flowing out from the first expansion valve 24 during the heating operation.
室外熱交換器23の図示しない冷媒パスの略中間部には、室外熱交換器23の温度である室外熱交温度を検出する熱交温度センサ75が設けられている。そして、室外機2の図示しない吸込口付近には、室外機2の内部に流入する外気の温度、すなわち外気温度を検出する外気温度センサ76が備えられている。
A heat exchange temperature sensor 75 for detecting the outdoor heat exchange temperature, which is the temperature of the outdoor heat exchanger 23, is provided at a substantially middle portion of a refrigerant path (not shown) of the outdoor heat exchanger 23. An outdoor air temperature sensor 76 that detects the temperature of the outdoor air flowing into the outdoor unit 2, that is, the outdoor air temperature is provided near the suction port (not shown) of the outdoor unit 2.
また、室外機2には、室外機制御手段200が備えられている。室外機制御手段200は、室外機2の図示しない電装品箱に格納されている制御基板に搭載されている。図1Bに示すように、室外機制御手段200は、CPU210と、記憶部220と、通信部230と、センサ入力部240を備えている(なお、本明細書では、室外機制御手段200を単に制御手段ということがある)。
Further, the outdoor unit 2 is provided with the outdoor unit control means 200. The outdoor unit control means 200 is mounted on a control board stored in an electric component box (not shown) of the outdoor unit 2. As shown in FIG. 1B, the outdoor unit control unit 200 includes a CPU 210, a storage unit 220, a communication unit 230, and a sensor input unit 240 (in this specification, the outdoor unit control unit 200 is simply referred to as the outdoor unit control unit 200. Sometimes called control means).
記憶部220は、フラッシュメモリで構成されており、室外機2の制御プログラムや各種センサからの検出信号に対応した検出値、圧縮機21や室外ファン27等の制御状態等を記憶している。また、図示は省略するが、記憶部220には室内機3から受信する要求能力に応じて圧縮機21の回転数を定めた回転数テーブルが予め記憶されている。
The storage unit 220 is composed of a flash memory, and stores a control program of the outdoor unit 2, detection values corresponding to detection signals from various sensors, control states of the compressor 21, the outdoor fan 27, and the like. Although not shown, the storage unit 220 stores in advance a rotation speed table in which the rotation speed of the compressor 21 is determined according to the required capacity received from the indoor unit 3.
通信部230は、室内機3との通信を行うインターフェイスである。センサ入力部240は、室外機2の各種センサでの検出結果を取り込んでCPU210に出力する。
The communication unit 230 is an interface that communicates with the indoor unit 3. The sensor input unit 240 takes in the detection results of various sensors of the outdoor unit 2 and outputs them to the CPU 210.
CPU210は、前述した室外機2の各センサでの検出結果を、センサ入力部240を介して取り込む。さらには、CPU210は、室内機3から送信される制御信号を、通信部230を介して取り込む。CPU210は、取り込んだ検出結果や制御信号等に基づいて、圧縮機21や室外ファン27の駆動制御を行う。また、CPU210は、取り込んだ検出結果や制御信号に基づいて、四方弁22の切替制御を行う。さらには、CPU210は、取り込んだ検出結果や制御信号に基づいて、第1膨張弁24及び第2膨張弁28の開度調整、インジェクション膨張弁29の開閉制御及び開度調整を行う。CPU210には、中圧レシーバ81内に液冷媒が貯まっているか否かを判定する液貯留判定部が設けられており、液貯留判定部は、詳しくは後述するように、中圧レシーバ81内に液冷媒が貯まっていると判定すると、インジェクション膨張弁29を開いて冷媒を圧縮機21の中圧へインジェクションを行う。
The CPU 210 fetches the detection result of each sensor of the outdoor unit 2 described above via the sensor input unit 240. Further, the CPU 210 takes in the control signal transmitted from the indoor unit 3 via the communication unit 230. The CPU 210 controls the drive of the compressor 21 and the outdoor fan 27 based on the captured detection result, control signal, and the like. The CPU 210 also controls the switching of the four-way valve 22 based on the captured detection result and control signal. Furthermore, the CPU 210 performs opening adjustment of the first expansion valve 24 and the second expansion valve 28, opening/closing control of the injection expansion valve 29, and opening adjustment based on the captured detection result and control signal. The CPU 210 is provided with a liquid storage determination unit that determines whether or not the liquid refrigerant is stored in the medium pressure receiver 81. The liquid storage determination unit is provided in the medium pressure receiver 81, as will be described later in detail. When it is determined that the liquid refrigerant is stored, the injection expansion valve 29 is opened to inject the refrigerant to the intermediate pressure of the compressor 21.
<<室内機の冷媒回路>>
次に、図1Aを用いて、室内機3について説明する。室内機3は、室内熱交換器31と、室内ファン32と、液管4の他端が接続された液管接続部33と、ガス管5の他端が接続されたガス管接続部34を備えている。そして、室内ファン32を除くこれら各装置が以下で詳述する各冷媒配管で相互に接続されて、冷媒回路10の一部をなす室内機冷媒回路10bを形成している。 <<Refrigerant circuit of indoor unit>>
Next, theindoor unit 3 will be described with reference to FIG. 1A. The indoor unit 3 includes an indoor heat exchanger 31, an indoor fan 32, a liquid pipe connecting portion 33 to which the other end of the liquid pipe 4 is connected, and a gas pipe connecting portion 34 to which the other end of the gas pipe 5 is connected. I have it. Each of these devices except the indoor fan 32 is connected to each other by respective refrigerant pipes described in detail below to form an indoor unit refrigerant circuit 10b forming a part of the refrigerant circuit 10.
次に、図1Aを用いて、室内機3について説明する。室内機3は、室内熱交換器31と、室内ファン32と、液管4の他端が接続された液管接続部33と、ガス管5の他端が接続されたガス管接続部34を備えている。そして、室内ファン32を除くこれら各装置が以下で詳述する各冷媒配管で相互に接続されて、冷媒回路10の一部をなす室内機冷媒回路10bを形成している。 <<Refrigerant circuit of indoor unit>>
Next, the
室内熱交換器31は、冷媒と後述する室内ファン32の回転により室内機3の図示しない吸込口から室内機3の内部に取り込まれた室内空気を熱交換させるものである。室内熱交換器31の一方の冷媒出入口は、液管接続部33と室内機液管67で接続されている。室内熱交換器31の他方の冷媒出入口は、ガス管接続部34と室内機ガス管68で接続されている。室内熱交換器31は、室内機3が冷房運転を行う場合は蒸発器として機能し、室内機3が暖房運転を行う場合は凝縮器として機能する。
The indoor heat exchanger 31 is for exchanging heat between the indoor air taken into the indoor unit 3 from the suction port (not shown) of the indoor unit 3 by the rotation of the refrigerant and the indoor fan 32 described later. One of the refrigerant inlet/outlet ports of the indoor heat exchanger 31 is connected to the liquid pipe connecting portion 33 by the indoor unit liquid pipe 67. The other refrigerant inlet/outlet of the indoor heat exchanger 31 is connected to the gas pipe connecting portion 34 by an indoor unit gas pipe 68. The indoor heat exchanger 31 functions as an evaporator when the indoor unit 3 performs a cooling operation, and functions as a condenser when the indoor unit 3 performs a heating operation.
室内ファン32は樹脂材で形成されており、室内熱交換器31の近傍に配置されている。室内ファン32は、図示しないファンモータによって回転することで、室内機3の図示しない吸込口から室内機3の内部に室内空気を取り込み、室内熱交換器31において冷媒と熱交換した室内空気を室内機3の図示しない吹出口から室内へ吹き出す。
The indoor fan 32 is made of a resin material and is arranged near the indoor heat exchanger 31. The indoor fan 32 is rotated by a fan motor (not shown) to take in indoor air into the interior of the indoor unit 3 from an intake port (not shown) of the indoor unit 3 and to exchange the indoor air with the refrigerant in the indoor heat exchanger 31 into the indoor air. The air is blown out into the room from an air outlet (not shown) of the machine 3.
以上説明した構成の他に、室内機3には各種のセンサが設けられている。室内機液管67には、室内熱交換器31に流入あるいは室内熱交換器31から流出する冷媒の温度を検出する液側温度センサ77aが設けられている。室内機ガス管68には、室内熱交換器31から流出あるいは室内熱交換器31に流入する冷媒の温度を検出するガス側温度センサ78が設けられている。そして、室内機3の図示しない吸込口付近には、室内機3の内部に流入する室内空気の温度、すなわち室温を検出する室温センサ79が備えられている。
In addition to the configuration described above, the indoor unit 3 is provided with various sensors. The indoor unit liquid pipe 67 is provided with a liquid side temperature sensor 77a that detects the temperature of the refrigerant flowing into or out of the indoor heat exchanger 31. The indoor unit gas pipe 68 is provided with a gas side temperature sensor 78 that detects the temperature of the refrigerant flowing out from the indoor heat exchanger 31 or flowing into the indoor heat exchanger 31. A room temperature sensor 79 for detecting the temperature of the room air flowing into the indoor unit 3, that is, the room temperature, is provided near the suction port (not shown) of the indoor unit 3.
<冷媒回路の動作の概要>
次に、本実施形態における空気調和機1の空調運転時の冷媒回路10における冷媒の流れや各部の動作について、より詳しくは図2から図11A,B,Cを用いて説明するが、図1Aを用いてその概要をまず説明する。以下では、図中、実線で示した冷媒の流れに基づいて、室内機3が暖房運転を行う場合について説明する。なお、破線で示した冷媒の流れが冷房運転を示している。 <Outline of operation of refrigerant circuit>
Next, the flow of the refrigerant and the operation of each part in therefrigerant circuit 10 during the air conditioning operation of the air conditioner 1 according to the present embodiment will be described in more detail with reference to FIGS. 2 to 11A, B, and C. First, the outline will be explained using. Below, the case where the indoor unit 3 performs the heating operation based on the flow of the refrigerant shown by the solid line in the figure will be described. The flow of the refrigerant shown by the broken line indicates the cooling operation.
次に、本実施形態における空気調和機1の空調運転時の冷媒回路10における冷媒の流れや各部の動作について、より詳しくは図2から図11A,B,Cを用いて説明するが、図1Aを用いてその概要をまず説明する。以下では、図中、実線で示した冷媒の流れに基づいて、室内機3が暖房運転を行う場合について説明する。なお、破線で示した冷媒の流れが冷房運転を示している。 <Outline of operation of refrigerant circuit>
Next, the flow of the refrigerant and the operation of each part in the
室内機3が暖房運転を行う場合、CPU210は、図1Aに示すように四方弁22を実線で示す状態、すなわち、四方弁22のポートaとポートdが連通するよう、また、ポートbとポートcが連通するよう、切り替える。これにより、冷媒回路10において実線矢印で示す方向に冷媒が循環し、室外熱交換器23が蒸発器として機能するとともに、室内熱交換器31が凝縮器として機能する暖房サイクルとなる。
When the indoor unit 3 performs the heating operation, the CPU 210 causes the four-way valve 22 to be in a state shown by a solid line as shown in FIG. 1A, that is, the port a and the port d of the four-way valve 22 communicate with each other and the port b and the port b. Switch so that c communicates. As a result, the refrigerant circulates in the refrigerant circuit 10 in the direction indicated by the solid line arrow, and the outdoor heat exchanger 23 functions as an evaporator, and the indoor heat exchanger 31 functions as a condenser.
圧縮機21から吐出された高圧の冷媒は、吐出管61を流れて四方弁22に流入する。四方弁22のポートaに流入した冷媒は、四方弁22のポートdから室外機ガス管64を流れて、ガス側閉鎖弁26を介してガス管5に流入する。ガス管5を流れる冷媒は、ガス管接続部34を介して室内機3に流入する。
The high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 61 and flows into the four-way valve 22. The refrigerant flowing into the port a of the four-way valve 22 flows from the port d of the four-way valve 22 through the outdoor unit gas pipe 64, and then flows into the gas pipe 5 via the gas side closing valve 26. The refrigerant flowing through the gas pipe 5 flows into the indoor unit 3 via the gas pipe connecting portion 34.
室内機3に流入した冷媒は、室内機ガス管68を流れて室内熱交換器31に流入し、室内ファン32の回転により室内機3の内部に取り込まれた室内空気と熱交換を行って凝縮する。このように、室内熱交換器31が凝縮器として機能し、室内熱交換器31で冷媒と熱交換を行った室内空気が図示しない吹出口から室内に吹き出されることによって、室内機3が設置された室内の暖房が行われる。
The refrigerant that has flowed into the indoor unit 3 flows through the indoor unit gas pipe 68 and flows into the indoor heat exchanger 31, where it exchanges heat with the indoor air taken into the indoor unit 3 by the rotation of the indoor fan 32 and condenses. To do. In this way, the indoor heat exchanger 31 functions as a condenser, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 is blown out into the room from an outlet (not shown), so that the indoor unit 3 is installed. The heated room is heated.
室内熱交換器31から流出した冷媒は、室内機液管67を流れ、液管接続部33を介して液管4に流入する。液管4を流れ、液側閉鎖弁25を介して室外機2に流入した冷媒は、室外機液管63を流れて第1膨張弁24、中圧レシーバ81、第2膨張弁28を通過する際に減圧される。上述したように、暖房運転時において、第1膨張弁24の開度は、室内熱交換器31流出後の冷媒の過冷却度(SC)が所定の目標値となるように、第2膨張弁28の開度は、圧縮機21の吐出温度が所定の目標値となるように調整されるか、若しくは、圧縮機21に吸入される冷媒の吸入過熱度(吸入SH)が所定の目標値となるように調整される。
The refrigerant flowing out of the indoor heat exchanger 31 flows through the indoor unit liquid pipe 67 and then flows into the liquid pipe 4 via the liquid pipe connection portion 33. The refrigerant flowing through the liquid pipe 4 and flowing into the outdoor unit 2 through the liquid side closing valve 25 flows through the outdoor unit liquid pipe 63 and passes through the first expansion valve 24, the intermediate pressure receiver 81, and the second expansion valve 28. When the pressure is reduced. As described above, during the heating operation, the opening degree of the first expansion valve 24 is set so that the degree of supercooling (SC) of the refrigerant after the indoor heat exchanger 31 flows out becomes a predetermined target value. The opening degree of 28 is adjusted so that the discharge temperature of the compressor 21 reaches a predetermined target value, or the suction superheat degree (intake SH) of the refrigerant sucked into the compressor 21 reaches a predetermined target value. Adjusted to be.
第1膨張弁24、中圧レシーバ81、第2膨張弁28を通過して室外熱交換器23に流入した冷媒は、室外ファン27の回転により室外機2の内部に取り込まれた外気と熱交換を行って蒸発する。室外熱交換器23から冷媒配管62に流出した冷媒は、四方弁22のポートb及びポートc、吸入管66を流れ、圧縮機21に吸入されて再び圧縮される。
The refrigerant that has passed through the first expansion valve 24, the intermediate pressure receiver 81, and the second expansion valve 28 and has flowed into the outdoor heat exchanger 23 exchanges heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 27. To evaporate. The refrigerant flowing from the outdoor heat exchanger 23 to the refrigerant pipe 62 flows through the ports b and c of the four-way valve 22 and the suction pipe 66, is sucked into the compressor 21 and is compressed again.
<冷媒回路の動作の詳細>
次に、本実施形態における空気調和機1の空調運転時の冷媒回路10における冷媒の流れや各部の動作について、図2から図11A,B,Cを用いて詳しく説明する。説明にあたっては、基本的な冷媒回路11、インジェクション回路65を有する冷媒回路12、中圧レシーバ81を有する冷媒回路13、そして、本実施形態に係るインジェクション回路65及び中圧レシーバ81を有する冷媒回路10を順に説明する。 <Details of refrigerant circuit operation>
Next, the flow of the refrigerant and the operation of each part in therefrigerant circuit 10 during the air conditioning operation of the air conditioner 1 in the present embodiment will be described in detail with reference to FIGS. 2 to 11A, B, and C. In the description, the basic refrigerant circuit 11, the refrigerant circuit 12 having the injection circuit 65, the refrigerant circuit 13 having the medium pressure receiver 81, and the refrigerant circuit 10 having the injection circuit 65 and the medium pressure receiver 81 according to the present embodiment. Will be described in order.
次に、本実施形態における空気調和機1の空調運転時の冷媒回路10における冷媒の流れや各部の動作について、図2から図11A,B,Cを用いて詳しく説明する。説明にあたっては、基本的な冷媒回路11、インジェクション回路65を有する冷媒回路12、中圧レシーバ81を有する冷媒回路13、そして、本実施形態に係るインジェクション回路65及び中圧レシーバ81を有する冷媒回路10を順に説明する。 <Details of refrigerant circuit operation>
Next, the flow of the refrigerant and the operation of each part in the
<<基本的な冷媒回路>>
図2及び図3を用いて、基本的な冷媒回路11について説明する。図2に示すように、冷媒回路11における基準点として、点Aは圧縮機21と凝縮器(暖房運転時の室内熱交換器31に対応。以下、凝縮器31と表記)の間、点Bは凝縮器31と膨張弁(暖房運転時の第2膨張弁28に対応。以下、膨張弁28と表記)の間、点Cは膨張弁28と蒸発器(暖房運転時の室外熱交換器23に対応。以下、蒸発器23と表記)の間、点Dは蒸発器23と圧縮機21の間を指す(以下同様)。 <<Basic refrigerant circuit>>
The basicrefrigerant circuit 11 will be described with reference to FIGS. 2 and 3. As shown in FIG. 2, as a reference point in the refrigerant circuit 11, the point A is between the compressor 21 and the condenser (corresponding to the indoor heat exchanger 31 during the heating operation. Hereinafter, referred to as the condenser 31), the point B. Is between the condenser 31 and the expansion valve (corresponding to the second expansion valve 28 during the heating operation; hereinafter referred to as the expansion valve 28), the point C is between the expansion valve 28 and the evaporator (the outdoor heat exchanger 23 during the heating operation). In the following, the point D indicates between the evaporator 23 and the compressor 21 (the same applies hereinafter).
図2及び図3を用いて、基本的な冷媒回路11について説明する。図2に示すように、冷媒回路11における基準点として、点Aは圧縮機21と凝縮器(暖房運転時の室内熱交換器31に対応。以下、凝縮器31と表記)の間、点Bは凝縮器31と膨張弁(暖房運転時の第2膨張弁28に対応。以下、膨張弁28と表記)の間、点Cは膨張弁28と蒸発器(暖房運転時の室外熱交換器23に対応。以下、蒸発器23と表記)の間、点Dは蒸発器23と圧縮機21の間を指す(以下同様)。 <<Basic refrigerant circuit>>
The basic
点Aから点D、又は各点間における冷媒の状態は、図3に示すように、以下のとおりとなる。(1)圧縮機21での圧縮過程の冷媒(点D~A間)は、圧縮され、圧力(縦軸)・温度共に上昇して高温高圧の過熱蒸気となる(周囲空気との熱交換で凝縮しやすい状態になる)。(2)圧縮機21から吐出された冷媒(点A)は、過熱状態の高圧気相冷媒である。(3)凝縮器31での凝縮過程の冷媒(点A~B間)は、周囲空気と熱交換(放熱)することで、圧力が一定のまま、過熱蒸気、飽和蒸気、湿り蒸気、飽和液の各状態を経て高圧の過冷却液となる。(4)凝縮器31から流出した冷媒(点B)は、過冷却状態の高圧液相冷媒である。(5)膨張弁28での膨張過程の冷媒(点B~C間)は、膨張し、圧力(縦軸)・温度共に下降して湿り蒸気となる(周囲空気との熱交換で蒸発しやすい状態になる)。(6)膨張弁28から流出した冷媒(点C)は、液リッチ(=液相比率が高い)状態の低圧二相冷媒である。(7)蒸発器23での蒸発過程の冷媒(点C~D間)は、周囲空気と熱交換(吸熱)することで、圧力が一定のまま、湿り蒸気、飽和蒸気、の各状態を経て低圧の過熱蒸気となる。(8)蒸発器23から流出した冷媒(点D)は、過熱状態の低圧気相冷媒である。
The state of the refrigerant from point A to point D, or between each point, is as follows, as shown in FIG. (1) The refrigerant (between points D and A) in the compression process in the compressor 21 is compressed, and both the pressure (vertical axis) and the temperature rise to become high-temperature and high-pressure superheated vapor (by heat exchange with ambient air). It becomes easy to condense). (2) The refrigerant (point A) discharged from the compressor 21 is a superheated high-pressure gas-phase refrigerant. (3) The refrigerant (between points A and B) in the condensation process in the condenser 31 exchanges heat (radiates heat) with the ambient air, so that the pressure remains constant and superheated steam, saturated steam, wet steam, saturated liquid After each of the above states, it becomes high-pressure supercooled liquid. (4) The refrigerant (point B) flowing out from the condenser 31 is a high-pressure liquid-phase refrigerant in a supercooled state. (5) The refrigerant (between points B and C) in the expansion process in the expansion valve 28 expands and both the pressure (vertical axis) and the temperature decrease to become wet vapor (it is easy to evaporate by heat exchange with ambient air). State). (6) The refrigerant (point C) flowing out from the expansion valve 28 is a low-pressure two-phase refrigerant in a liquid rich (=high liquid phase ratio) state. (7) The refrigerant in the evaporation process in the evaporator 23 (between points C and D) exchanges heat with the ambient air (endothermic heat), so that the pressure of the refrigerant remains constant and passes through the states of wet steam and saturated steam. It becomes low pressure superheated steam. (8) The refrigerant (point D) flowing out from the evaporator 23 is a superheated low-pressure gas-phase refrigerant.
この基本的な冷媒回路11における制御対象である圧縮機21、室内ファン32、膨張弁28及び室外ファン27の制御方法は、次のとおりである。圧縮機21は、室内機3側の要求される能力に基づいて制御される(要求される能力:室内熱交換器31(暖房運転時:凝縮器、冷房時:蒸発器)の周囲温度(=室温)と目標温度の差に応じて設定)。室内ファン32は、暖房運転時(凝縮器が室内熱交換器31の場合)冷房運転時(凝縮器が室外熱交換器23の場合)ともに室温と設定温度の差に応じて制御、若しくはユーザによって好みの風量となるように設定される。膨張弁28は、点Aの温度(吐出温度)が目標値となるように制御(吐出温度制御)、又は、圧縮機21の回転数の変化量に応じて予め定めた制御量(パルス)で膨張弁28の開度を調整する制御(回転数パルス制御)によって制御される。なお、吐出温度制御は、室内温度や外気温等の外乱が吐出温度の変化に現れてから開度調整を行うフィードバック制御であるのに対し、回転数パルス制御は、回転数の変化量から循環量の変化量を予測して予め膨張弁28が適正な開度となるように調整を行うフィードフォワード制御である。室外ファン27は、暖房運転時(蒸発器が熱源側の場合)冷房運転時(蒸発器が利用側の場合)ともに圧縮機21の回転数に基づいて制御される。
The control method of the compressor 21, the indoor fan 32, the expansion valve 28, and the outdoor fan 27, which are the objects to be controlled in this basic refrigerant circuit 11, is as follows. The compressor 21 is controlled based on the required capacity on the indoor unit 3 side (required capacity: indoor heat exchanger 31 (heating operation: condenser, cooling: evaporator) ambient temperature (= Set according to the difference between room temperature) and the target temperature). The indoor fan 32 is controlled according to the difference between the room temperature and the set temperature during heating operation (when the condenser is the indoor heat exchanger 31) and during cooling operation (when the condenser is the outdoor heat exchanger 23), or by the user. It is set to obtain the desired air volume. The expansion valve 28 is controlled so that the temperature of the point A (discharge temperature) reaches a target value (discharge temperature control), or a control amount (pulse) determined in advance according to the amount of change in the rotation speed of the compressor 21. The expansion valve 28 is controlled by a control for adjusting the opening degree (rotational speed pulse control). The discharge temperature control is a feedback control that adjusts the opening degree after a disturbance such as the room temperature or the outside air temperature appears in the change of the discharge temperature, whereas the rotation speed pulse control circulates from the change amount of the rotation speed. This is feedforward control in which the amount of change in the amount is predicted and the expansion valve 28 is adjusted in advance so as to have an appropriate opening. The outdoor fan 27 is controlled based on the rotation speed of the compressor 21 both during heating operation (when the evaporator is on the heat source side) and during cooling operation (when the evaporator is on the use side).
基本的な冷媒回路11における運転上の制約は、次のとおりである。点Bでは冷媒が液相状態である(=過冷却が取れている)ことが求められる。なぜならば、膨張弁28に二相冷媒が流入すると、冷媒流動音の発生や、制御性の悪化などの不都合が生じるからである。点Dでは冷媒が気相状態である(=過熱が取れている)ことが求められる。なぜならば、圧縮機21に液相冷媒が流入すると液圧縮(液相冷媒は非圧縮性であるため、圧縮機21が破損する。)し、信頼性が低下するからである。
The basic operational restrictions in the refrigerant circuit 11 are as follows. At point B, the refrigerant is required to be in a liquid phase (=subcooled). The reason is that when the two-phase refrigerant flows into the expansion valve 28, there arises inconveniences such as generation of refrigerant flow noise and deterioration of controllability. At the point D, the refrigerant is required to be in a gas phase (=overheated). This is because when the liquid-phase refrigerant flows into the compressor 21, liquid compression (the compressor 21 is damaged because the liquid-phase refrigerant is incompressible) and reliability is reduced.
<<インジェクション回路を有する冷媒回路>>
図4及び図5を用いて、インジェクション回路65を有する冷媒回路12について説明する。図4に示すように、インジェクション回路65を有する冷媒回路12では、凝縮器31からの流出後の冷媒の一部を圧縮機21の中間圧へ流入させる。インジェクション回路65には、圧縮機21へインジェクションする冷媒量を調整するインジェクション膨張弁29を備えるとともに、インジェクションする冷媒の乾き度を上げるため、冷媒間熱交換器82(SC熱交換器)を備える。 <<Refrigerant Circuit Having Injection Circuit>>
Therefrigerant circuit 12 having the injection circuit 65 will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, in the refrigerant circuit 12 having the injection circuit 65, a part of the refrigerant after flowing out from the condenser 31 is caused to flow into the intermediate pressure of the compressor 21. The injection circuit 65 includes an injection expansion valve 29 that adjusts the amount of refrigerant injected into the compressor 21, and an inter-refrigerant heat exchanger 82 (SC heat exchanger) to increase the dryness of the injected refrigerant.
図4及び図5を用いて、インジェクション回路65を有する冷媒回路12について説明する。図4に示すように、インジェクション回路65を有する冷媒回路12では、凝縮器31からの流出後の冷媒の一部を圧縮機21の中間圧へ流入させる。インジェクション回路65には、圧縮機21へインジェクションする冷媒量を調整するインジェクション膨張弁29を備えるとともに、インジェクションする冷媒の乾き度を上げるため、冷媒間熱交換器82(SC熱交換器)を備える。 <<Refrigerant Circuit Having Injection Circuit>>
The
図4に示すように、冷媒回路12の基準点としては、点A~Dのほかに点E~Gが加えられ、点Eは冷媒間熱交換器82の室外機液管63側流路出口と膨張弁28の間、点Fはインジェクション膨張弁29と冷媒間熱交換器82のインジェクション回路65側流路入口の間、点Gは冷媒間熱交換器82のインジェクション回路65側流路出口と圧縮機21の間を指す(以下同様)。
As shown in FIG. 4, points E to G are added to the reference points of the refrigerant circuit 12 in addition to points A to D, and the point E is the outdoor unit liquid pipe 63 side flow path outlet of the inter-refrigerant heat exchanger 82. Between the injection expansion valve 28 and the expansion valve 28, a point F between the injection expansion valve 29 and the injection circuit 65 side flow path inlet of the inter-refrigerant heat exchanger 82, and a point G is the injection circuit 65 side flow path outlet of the inter-refrigerant heat exchanger 82. It points between the compressors 21 (same below).
インジェクション回路65の目的は、凝縮器31の冷媒循環量を増やす(低外気(-20~-30℃)暖房運転時等、暖房能力を上昇させる)こと、また、圧縮機21の吐出温度を下げる(低外気暖房運転時等、蒸発温度を外気温度よりも低くすることで、高圧(凝縮圧力)と低圧(蒸発圧力)の圧力差が大きくなっても、圧縮機21の温度が異常温度とならないようにする)ことである。
The purpose of the injection circuit 65 is to increase the refrigerant circulation amount of the condenser 31 (to increase the heating capacity during low outside air (−20 to −30° C.) heating operation, etc.) and to lower the discharge temperature of the compressor 21. (By setting the evaporation temperature lower than the outside air temperature during low outside air heating operation, the temperature of the compressor 21 does not become an abnormal temperature even if the pressure difference between the high pressure (condensing pressure) and the low pressure (evaporating pressure) becomes large. It is that).
冷媒回路12における冷媒の状態は、図5に示すようになるが、冷媒回路11と異なる点は以下のとおりとなる。(1)圧縮機21での圧縮過程の点D~A間において、インジェクション回路65を介して凝縮過程の冷媒の一部が二相状態で圧縮機21の中間圧に流入することにより、圧縮機21で圧縮される冷媒の温度が圧縮途中で低下し、インジェクション回路65に冷媒を循環させない場合と比較して点Aにおける吐出温度が下がる。(2)冷媒は、凝縮過程の点A~B間を通過して液相状態になった後、点B~E間においてインジェクション回路65の点F~G間を流れる冷媒と冷媒間熱交換器82によって熱交換され過冷却される。(3)点A~B間から分岐したインジェクション回路65に流入した冷媒は、点B~F間でインジェクション膨張弁29を介して低圧の二相状態になり、その後、点F~G間において点B~E間を流れる冷媒と冷媒間熱交換器82によって熱交換されて乾き度が上昇し、点Gから圧縮過程の点D~A間にインジェクションされる。
The state of the refrigerant in the refrigerant circuit 12 is as shown in FIG. 5, but the points different from the refrigerant circuit 11 are as follows. (1) Between points D and A in the compression process of the compressor 21, a part of the refrigerant in the condensation process flows into the intermediate pressure of the compressor 21 in a two-phase state via the injection circuit 65, and The temperature of the refrigerant compressed in 21 decreases during the compression, and the discharge temperature at point A decreases compared to the case where the refrigerant is not circulated in the injection circuit 65. (2) The refrigerant passes between points A and B in the condensation process and becomes a liquid phase state, and then flows between points F and G of the injection circuit 65 between points B and E and the heat exchanger between refrigerants. The heat is exchanged and supercooled by 82. (3) The refrigerant flowing into the injection circuit 65 branched from the points A to B becomes a low-pressure two-phase state via the injection expansion valve 29 between the points B to F, and then becomes a point between the points F and G. The refrigerant flowing between B and E is heat-exchanged by the inter-refrigerant heat exchanger 82 to increase the dryness, and is injected from the point G to the points D to A of the compression process.
この冷媒回路12における特徴的な制御対象である膨張弁28及びインジェクション膨張弁29の制御方法は、次のとおりである。膨張弁28は、インジェクションをしない場合は、点Aの温度(吐出温度)が目標値となるように制御(吐出温度制御)し、また、圧縮機21の回転数の変化量に応じて予め定めた制御量(パルス)で膨張弁28の開度を調整するように制御(回転数パルス制御)する。インジェクションを行う場合は、吸入SH(=点Dの温度-点Cの温度)が目標値となるように制御(吸入SH制御)し、圧縮機21の回転数の変化量に応じて予め定めた制御量(パルス)で膨張弁28の開度を調整するように制御(回転数パルス制御)する。インジェクション膨張弁29は、インジェクションをしない場合は、閉じる。インジェクションを行う場合は、点Aの温度(吐出温度)又は吐出SHが目標値となるように制御(吐出温度制御又は吐出SH制御)する。
The control method of the expansion valve 28 and the injection expansion valve 29, which are characteristic objects to be controlled in the refrigerant circuit 12, are as follows. When injection is not performed, the expansion valve 28 controls the temperature (discharge temperature) of the point A to be a target value (discharge temperature control), and is predetermined according to the amount of change in the rotation speed of the compressor 21. Control (rotation speed pulse control) is performed to adjust the opening degree of the expansion valve 28 by the controlled amount (pulse). When performing injection, control is performed so that the suction SH (=temperature at point D-temperature at point C) reaches a target value (suction SH control), and predetermined according to the amount of change in the rotation speed of the compressor 21. Control (rotation speed pulse control) is performed so as to adjust the opening degree of the expansion valve 28 with a control amount (pulse). The injection expansion valve 29 is closed when injection is not performed. When performing injection, control is performed so that the temperature at point A (discharge temperature) or discharge SH reaches a target value (discharge temperature control or discharge SH control).
<<中圧レシーバを有する冷媒回路>>
図6及び図7を用いて、中圧レシーバ81を有する冷媒回路13について説明する。図6に示すように、冷媒回路13の基準点は、基本的な冷媒回路11と同様に点A~Dである。 <<Refrigerant circuit with medium pressure receiver>>
Therefrigerant circuit 13 including the intermediate pressure receiver 81 will be described with reference to FIGS. 6 and 7. As shown in FIG. 6, the reference points of the refrigerant circuit 13 are points A to D as in the basic refrigerant circuit 11.
図6及び図7を用いて、中圧レシーバ81を有する冷媒回路13について説明する。図6に示すように、冷媒回路13の基準点は、基本的な冷媒回路11と同様に点A~Dである。 <<Refrigerant circuit with medium pressure receiver>>
The
中圧レシーバ81の目的は、接続される室内機3の大きさを問わず、適切な冷媒量に調整することである。これは、室内熱交換器31の大きさや、各所の配管の長さ(管内容積)によって冷媒回路13に必要な冷媒量が異なることに対応するものである。ここで、「必要な冷媒量が異なる」とは、効率の良い、信頼性的に問題ない運転(適性吸入SH、SC)を行うために必要な冷媒量は室内熱交換器大きさや接続配管長さといった容積差で異なることを意味しており、中圧レシーバ81内は、その内部の冷媒を冷媒回路13内に出入りさせることで調整する。
The purpose of the medium pressure receiver 81 is to adjust the amount of refrigerant to an appropriate amount, regardless of the size of the indoor unit 3 to be connected. This corresponds to the fact that the amount of refrigerant required for the refrigerant circuit 13 differs depending on the size of the indoor heat exchanger 31 and the lengths of pipes (internal volume) at various places. Here, "the required amount of refrigerant is different" means that the amount of refrigerant required for efficient and reliable operation (appropriate suction SH, SC) is the size of the indoor heat exchanger and the length of the connecting pipe. This means that there is a difference in volume due to such a difference, and the inside of the intermediate pressure receiver 81 is adjusted by letting the refrigerant inside the refrigerant circuit 13 flow in and out.
中圧レシーバ81を有する冷媒回路13では、凝縮器31と蒸発器23の間に中圧レシーバ81を備えており、中圧レシーバ81の上流側と下流側にはそれぞれ、第1膨張弁24と第2膨張弁28が設けられている。冷媒回路13における冷媒の状態は、図7に示すように、基本的な冷媒回路11と実質的に同様である。
The refrigerant circuit 13 having the medium pressure receiver 81 includes the medium pressure receiver 81 between the condenser 31 and the evaporator 23, and the first expansion valve 24 and the first expansion valve 24 are provided on the upstream side and the downstream side of the medium pressure receiver 81, respectively. A second expansion valve 28 is provided. The state of the refrigerant in the refrigerant circuit 13 is substantially the same as that of the basic refrigerant circuit 11, as shown in FIG. 7.
この冷媒回路13における特徴的な制御対象である第1膨張弁24及び第2膨張弁28の制御方法は、次のとおりである。第1膨張弁24は、SC、すなわち、過冷却度(=点A~B間の二相域の温度-点Bの温度)が目標値となるように制御(SC制御)する。第2膨張弁28は、点Aの温度(吐出温度)が目標値となるように制御(吐出温度制御)、若しくは、吸入SH、すなわち、吸入過熱度(=点Dの温度-点Cの温度)が目標値となるように制御(吸入SH制御)する。
The control method of the first expansion valve 24 and the second expansion valve 28, which are characteristic control objects in the refrigerant circuit 13, are as follows. The first expansion valve 24 performs control (SC control) so that SC, that is, the degree of supercooling (=temperature in the two-phase region between points A and B-temperature at point B) becomes a target value. The second expansion valve 28 is controlled so that the temperature at point A (discharge temperature) becomes a target value (discharge temperature control), or suction SH, that is, the degree of suction superheat (=temperature at point D-temperature at point C). ) Becomes a target value (intake SH control).
<<本実施形態に係るインジェクション回路及び中圧レシーバを有する冷媒回路>>
本実施形態に係る冷媒回路10について、図8及び図9を用いて説明する。図1A,Bに示したように、冷媒回路10は、上記で説明したインジェクション回路65及び中圧レシーバ81の双方を備えている。図8は、図1A,Bを簡略化して冷媒回路10を図示したものであり、図4のインジェクション回路65を有する冷媒回路12において、インジェクション回路65が分岐する手前(上流側)に第1膨張弁24と中圧レシーバ81を設けた態様となる。図4における膨張弁28は、第2膨張弁28となる。図8に示すように、冷媒回路10の基準点としては、点A~D、点E~Gのほかに点Hが加えられ、点Hは第1膨張弁24と中圧レシーバ81の間を指す。 <<Refrigerant Circuit Having Injection Circuit and Medium Pressure Receiver According to Present Embodiment>>
Therefrigerant circuit 10 according to this embodiment will be described with reference to FIGS. 8 and 9. As shown in FIGS. 1A and 1B, the refrigerant circuit 10 includes both the injection circuit 65 and the intermediate pressure receiver 81 described above. FIG. 8 shows the refrigerant circuit 10 by simplifying FIGS. 1A and 1B. In the refrigerant circuit 12 having the injection circuit 65 of FIG. 4, the first expansion is performed before the injection circuit 65 branches (upstream side). This is a mode in which the valve 24 and the intermediate pressure receiver 81 are provided. The expansion valve 28 in FIG. 4 becomes the second expansion valve 28. As shown in FIG. 8, as the reference point of the refrigerant circuit 10, a point H is added in addition to the points A to D and points E to G, and the point H is between the first expansion valve 24 and the intermediate pressure receiver 81. Point to.
本実施形態に係る冷媒回路10について、図8及び図9を用いて説明する。図1A,Bに示したように、冷媒回路10は、上記で説明したインジェクション回路65及び中圧レシーバ81の双方を備えている。図8は、図1A,Bを簡略化して冷媒回路10を図示したものであり、図4のインジェクション回路65を有する冷媒回路12において、インジェクション回路65が分岐する手前(上流側)に第1膨張弁24と中圧レシーバ81を設けた態様となる。図4における膨張弁28は、第2膨張弁28となる。図8に示すように、冷媒回路10の基準点としては、点A~D、点E~Gのほかに点Hが加えられ、点Hは第1膨張弁24と中圧レシーバ81の間を指す。 <<Refrigerant Circuit Having Injection Circuit and Medium Pressure Receiver According to Present Embodiment>>
The
冷媒回路10における冷媒の状態は、図9に示すようになるが、冷媒回路12と異なる点は以下のとおりとなる。(1)冷媒は、凝縮過程の点A~B間を経た後、点B~H間で第1膨張弁24を介して圧力が下がり、その後、点H~E間においてインジェクション回路65の点F~G間と冷媒間熱交換器82によって熱交換される。(2)点A~E間の点Hから分岐したインジェクション回路65に流入した冷媒は、点H~F間でインジェクション膨張弁29を介して圧力が下がり、その後、点F~G間において点B~E間と冷媒間熱交換器82によって熱交換されて乾き度が上昇し、点Gから圧縮過程の点D~A間にインジェクションされる。
The state of the refrigerant in the refrigerant circuit 10 is as shown in FIG. 9, but the points different from the refrigerant circuit 12 are as follows. (1) The pressure of the refrigerant decreases after passing through points A and B in the condensation process through the first expansion valve 24 between points B and H, and then between points H and E at point F of the injection circuit 65. Heat is exchanged between G and G by the heat exchanger 82 between refrigerants. (2) The pressure of the refrigerant flowing into the injection circuit 65 branched from the point H between the points A to E decreases via the injection expansion valve 29 between the points H to F, and then the point B between the points F and G. To E and heat is exchanged by the heat exchanger 82 between refrigerants to increase the dryness, and injection is performed from the point G to the points D to A in the compression process.
<<冷房運転時の処理の流れ>>
ここで、凝縮温度と周囲温度の差とSC制御の関係について、図11A,B,Cを用いて説明する。図11Aは、凝縮温度と周囲温度の差(以下、Δtとする)とSC値との関係を一般的に示している。図11Bに示すように、SCmin(1~2deg)を下回る範囲については、Δtの値に関わらず冷媒が凝縮器23から第2膨張弁28に流れるまでの間に圧力損失によって二相化してしまい、冷媒流動音(騒音)が発生する可能性がある。 <<Processing flow during cooling operation>>
Here, the relationship between the difference between the condensation temperature and the ambient temperature and the SC control will be described with reference to FIGS. 11A, 11B and 11C. FIG. 11A generally shows the relationship between the difference between the condensation temperature and the ambient temperature (hereinafter referred to as Δt) and the SC value. As shown in FIG. 11B, in the range below SCmin (1 to 2 deg), regardless of the value of Δt, the refrigerant becomes two-phase due to the pressure loss before flowing from thecondenser 23 to the second expansion valve 28. , Refrigerant flow noise (noise) may occur.
ここで、凝縮温度と周囲温度の差とSC制御の関係について、図11A,B,Cを用いて説明する。図11Aは、凝縮温度と周囲温度の差(以下、Δtとする)とSC値との関係を一般的に示している。図11Bに示すように、SCmin(1~2deg)を下回る範囲については、Δtの値に関わらず冷媒が凝縮器23から第2膨張弁28に流れるまでの間に圧力損失によって二相化してしまい、冷媒流動音(騒音)が発生する可能性がある。 <<Processing flow during cooling operation>>
Here, the relationship between the difference between the condensation temperature and the ambient temperature and the SC control will be described with reference to FIGS. 11A, 11B and 11C. FIG. 11A generally shows the relationship between the difference between the condensation temperature and the ambient temperature (hereinafter referred to as Δt) and the SC value. As shown in FIG. 11B, in the range below SCmin (1 to 2 deg), regardless of the value of Δt, the refrigerant becomes two-phase due to the pressure loss before flowing from the
また、凝縮器を流れる冷媒は、周囲温度の空気によって冷やされるため、SCの限界値はΔtとなる。そのため、SC>Δtの領域(X領域)に目標SC値を設定した場合、目標SC値に到達させることが不可能となる。よって、目標SCを設定する条件は、「SCmin≦目標SC≦Δt」の領域(Y領域およびZ領域)である。
Also, the refrigerant flowing through the condenser is cooled by the air at ambient temperature, so the SC limit value is Δt. Therefore, when the target SC value is set in the region of SC>Δt (X region), it becomes impossible to reach the target SC value. Therefore, the condition for setting the target SC is the region (Y region and Z region) of “SCmin≦target SC≦Δt”.
一方、「目標SC≦Δt」であっても、SC=Δtや、それに近い領域(Δt*α<SC≦Δt(0<α≦1のとき))でも、SC値が目標SCに到達するのに時間がかかる。これは、凝縮温度と周囲温度との温度勾配が小さい程、単位時間当たりに移動する熱量は小さくなるためである。よって、SC=Δtや、それに近い領域(Δt*α<SC≦Δt (0<α≦1のとき))に目標SCを設定しないことが好ましい。また、もしSC=Δtや、それに近い領域(Δt*α<SC≦Δt (0<α<1のとき))に目標SCを設定した場合、凝縮器の内部において液単相の冷媒が流れる経路が長くなる。これは、当該領域に目標SCを設定すると、凝縮器の内部で過冷却された液単相冷媒が目標SCとなるまで膨張弁の開度が小さくなる。前述の通り、単位時間当たりに移動する熱量は小さいため、凝縮器の内部で過冷却が始まってから、凝縮器出口側の冷媒が目標SCとなるまで、十分な経路の長さをかけて周囲温度の空気で冷媒を冷やす必要がある。その結果、凝縮器の内部において液単相の冷媒が流れる経路が長くなるため、凝縮器の内部において液単相の冷媒が多く溜まってしまう。凝縮器の内部の流路のうち、液冷媒が多く溜まっている液単相領域は、冷媒が潜熱変化をしないため、空気との熱交換にあまり寄与しない。すなわち、当該領域(Δt*α<SC≦Δt)では、空気との熱交換に寄与しない液単相領域が増えるため、熱交換器の熱交換効率が低下する。よって、目標SCを設定する好ましい条件は、「SCmin≦目標SC≦Δt*α」の領域(Z領域)である。なお、このときのαは予め試験などを行い定めたものであり(例えば、0.2≦α≦0.8、好ましくはα=0.5)、Δtの値に対して空気調和機としての性能(例えばCOP)が最も良くなるSC値とする。
On the other hand, even if “target SC≦Δt”, the SC value reaches the target SC even if SC=Δt or a region close to it (Δt*α<SC≦Δt (when 0<α≦1)). Takes time. This is because the smaller the temperature gradient between the condensation temperature and the ambient temperature, the smaller the amount of heat that moves per unit time. Therefore, it is preferable not to set the target SC in SC=Δt or a region close to it (Δt*α<SC≦Δt (when 0<α≦1)). Also, if the target SC is set in SC=Δt or a region close to it (Δt*α<SC≦Δt (when 0<α<1)), the passage of the liquid single-phase refrigerant inside the condenser. Becomes longer. This is because when the target SC is set in this region, the opening degree of the expansion valve becomes small until the liquid single-phase refrigerant supercooled inside the condenser reaches the target SC. As described above, since the amount of heat that moves per unit time is small, it takes a sufficient length of the path from the start of supercooling inside the condenser until the refrigerant on the outlet side of the condenser reaches the target SC. It is necessary to cool the refrigerant with temperature air. As a result, since the path through which the liquid single-phase refrigerant flows inside the condenser becomes long, a large amount of the liquid single-phase refrigerant accumulates inside the condenser. In the flow path inside the condenser, the liquid single-phase region where a large amount of liquid refrigerant is accumulated does not contribute to heat exchange with air because the refrigerant does not change in latent heat. That is, in the region (Δt*α<SC≦Δt), the liquid single-phase region that does not contribute to heat exchange with air increases, so that the heat exchange efficiency of the heat exchanger decreases. Therefore, a preferable condition for setting the target SC is a region (Z region) of “SCmin≦target SC≦Δt*α”. In addition, at this time, α is determined in advance by performing a test or the like (for example, 0.2≦α≦0.8, preferably α=0.5), and the value of Δt corresponds to an air conditioner. The SC value is the one that gives the best performance (for example, COP).
図11Bは、従来例において目標SC値を固定した場合すなわち一定値にした場合を示している。図中の太線が目標SC値SCt(固定)である。Δtが小さい領域A1では、空気調和機としての性能(例えばCOP)が最も良くなるSC値(SC=Δt*α)に対して目標SC値SCt(固定)が大きい。そのため、室外機制御手段200のCPU210は、SCが目標SC値となるように第2膨張弁28の開度を過剰に小さくする。その結果、凝縮器23に液冷媒が溜り、空気との熱交換に寄与しない液単相領域が増えて熱交換効率が低下する。また、凝縮器23に液冷媒が溜ることで、蒸発器31に流れる冷媒の量が減るため、圧縮機21に吸入される冷媒の温度が上昇する。そのため、圧縮機21の信頼性低下や、吐出温度の過昇による圧縮機21の保護動作により能力低下が発生する。また、Δtが小さい領域A1では、凝縮温度と周囲温度との差が小さく、SC値を上昇させにくく、目標SCが高い(SCt>Δt*α)程、SC値を目標SCに到達させるのに時間がかかる。
FIG. 11B shows a case where the target SC value is fixed, that is, a fixed value, in the conventional example. The thick line in the figure is the target SC value SCt (fixed). In the region A1 where Δt is small, the target SC value SCt (fixed) is large with respect to the SC value (SC=Δt*α) at which the performance (for example, COP) as the air conditioner is the best. Therefore, the CPU 210 of the outdoor unit control means 200 excessively reduces the opening degree of the second expansion valve 28 so that SC becomes the target SC value. As a result, the liquid refrigerant accumulates in the condenser 23, and the liquid single-phase region that does not contribute to heat exchange with the air increases, and the heat exchange efficiency decreases. Further, since the amount of the refrigerant flowing to the evaporator 31 is reduced due to the liquid refrigerant accumulated in the condenser 23, the temperature of the refrigerant drawn into the compressor 21 rises. Therefore, the reliability of the compressor 21 is lowered, and the capacity is lowered due to the protective operation of the compressor 21 due to the excessive rise in the discharge temperature. Further, in the region A1 where Δt is small, the difference between the condensing temperature and the ambient temperature is small, it is difficult to increase the SC value, and the higher the target SC (SCt>Δt*α), the more the SC value reaches the target SC. take time.
一方、Δtが大きい領域A2では、空気調和機としての性能(例えばCOP)が最も良くなるSC値(SC=Δt*α)に対して目標SC値SCt(固定)が小さい。そのため、CPU210は、第2膨張弁28の開度を過剰に大きくする。周囲温度に対し凝縮温度が大きいときは、凝縮器23に液冷媒が多く溜まっているが、第2膨張弁28の開度を大きくことで、冷媒が中圧レシーバ81に流れ込む。中圧レシーバ81の下流側に位置する蒸発器側膨張弁24は、第2膨張弁28から流出した液冷媒の量によらず、圧縮機21に吸入される冷媒の吸入過熱度(吸入SH)が所定の目標値となるように調整される。そのため、目標SC値を固定した場合、中圧レシーバ81は、第2膨張弁28から流出した冷媒を貯めるために十分な容積が必要である。すなわち、空気調和機の大型化に繋がってしまう。
On the other hand, in the area A2 in which Δt is large, the target SC value SCt (fixed) is small with respect to the SC value (SC=Δt*α) at which the performance (for example, COP) as the air conditioner is the best. Therefore, the CPU 210 excessively increases the opening degree of the second expansion valve 28. When the condensation temperature is higher than the ambient temperature, a large amount of the liquid refrigerant is stored in the condenser 23, but the refrigerant flows into the intermediate pressure receiver 81 by increasing the opening degree of the second expansion valve 28. The evaporator-side expansion valve 24 located on the downstream side of the intermediate pressure receiver 81 does not depend on the amount of the liquid refrigerant flowing out from the second expansion valve 28, and the suction superheat degree (suction SH) of the refrigerant sucked into the compressor 21. Is adjusted to a predetermined target value. Therefore, when the target SC value is fixed, the medium pressure receiver 81 needs to have a sufficient volume to store the refrigerant flowing out from the second expansion valve 28. That is, it leads to an increase in the size of the air conditioner.
以上に対し、図11Cは、実施形態の空気調和機において目標SC値を多段階に変化する場合を示している。図中の太線が目標SC値SCt(変化)である。本実施形態では、Δtに応じて目標SC値を4段階(第1目標SC値、第2目標SC値、第3目標SC値、第4目標SC値)に切り替えるものである。
In contrast, FIG. 11C shows a case where the target SC value is changed in multiple stages in the air conditioner of the embodiment. The thick line in the figure is the target SC value SCt (change). In the present embodiment, the target SC value is switched to four levels (first target SC value, second target SC value, third target SC value, fourth target SC value) according to Δt.
Δtが小さい領域A3では、図11Bの目標SC値(固定)より小さい第1目標SC値に切替えられる。第1目標SC値について、制御性及び騒音対策として最低限必要なSC値(例えば、2deg)が目標SC値となるように、Δtに対応する目標SC値SCtを予め記憶部220に記憶しておく。制御性及び騒音対策として最低限必要なSC値は、冷媒が凝縮器23から第2膨張弁28に流れるまでの間に圧力損失によって二相化し、冷媒流動音(騒音)が発生することのない最低限のSC値を予め試験など行い定めるものとする。
In the area A3 where Δt is small, the first target SC value smaller than the target SC value (fixed) in FIG. 11B is switched. Regarding the first target SC value, the target SC value SCt corresponding to Δt is stored in the storage unit 220 in advance so that the minimum SC value (for example, 2 deg) required for controllability and noise countermeasures becomes the target SC value. deep. The minimum SC value required for controllability and noise control is two-phased due to pressure loss until the refrigerant flows from the condenser 23 to the second expansion valve 28, and refrigerant flow noise (noise) does not occur. The minimum SC value shall be determined by conducting a test beforehand.
一方、Δtが大きい領域A4では、図11Bの目標SC値(固定)より大きい第3目標SC値に切替えられる。空気調和機としての性能(例えばCOP)が最も良くなるSC値が目標SC値(例えば6deg)となるようにΔtに対応する目標SC値SCtを予め記憶部220に記憶しておく。目標SC値は、予め試験などにより定め、記憶部220に記憶される。また、Δtが大きい領域A4における目標SC値SCtは、「SC=Δt*α」と「SC=SCmin」の中央値でもよい。これにより、空調負荷などが変化した際に、一時的に「Δt*α」を超える、若しくは、「SCmin」未満になることを防止することができる。SC<SCminになってしまうと一時的な騒音が生じ、SC>Δt*αになると熱交換器の熱交換効率が低下する。また、このように目標SC値SCtを設定すると、凝縮器23に液冷媒を溜めることができるので、中圧レシーバ81に必要な容積を低減することができる。
On the other hand, in the area A4 where Δt is large, it is switched to the third target SC value larger than the target SC value (fixed) in FIG. 11B. The target SC value SCt corresponding to Δt is stored in advance in the storage unit 220 so that the SC value that maximizes the performance (for example, COP) as the air conditioner becomes the target SC value (for example, 6 deg). The target SC value is determined in advance by a test or the like and stored in the storage unit 220. Further, the target SC value SCt in the area A4 where Δt is large may be the median value of “SC=Δt*α” and “SC=SCmin”. As a result, when the air conditioning load or the like changes, it is possible to prevent temporarily from exceeding “Δt*α” or less than “SCmin”. When SC<SCmin, temporary noise occurs, and when SC>Δt*α, the heat exchange efficiency of the heat exchanger decreases. Further, when the target SC value SCt is set in this way, the liquid refrigerant can be stored in the condenser 23, so that the volume required for the intermediate pressure receiver 81 can be reduced.
また、空気調和機としての性能(例えばCOP)が最も良くなるSC値について説明する。COPは、凝縮過程、又は、蒸発過程のエンタルピー差を圧縮過程のエンタルピー差で除した値である。すなわち、圧縮過程のエンタルピー差を増加させずに凝縮過程、又は、蒸発過程のエンタルピー差を増加させることができれば、COPは向上する。目標SC値は、大きくした方が凝縮過程におけるエンタルピー差が大きくなる。つまり、できるだけ目標SC値を大きくすることで、性能が良くなる。しかし、目標SC値を大きくし過ぎる(Δt*α<SC)と、SC値が目標SCに到達するのに時間がかかる。SC値が目標SC値に到達するまで膨張弁28の開度は小さくなっていくため、蒸発器に流れる冷媒密度が低下して、圧縮機21の信頼性が低下するなどの問題が生じる。したがって、空気調和機としての性能(例えばCOP)が最も良くなる、且つ、圧縮機21の信頼性を確保できるSC値を選択して目標SC値とすることができる。
Also, the SC value that gives the best performance (eg COP) as an air conditioner will be explained. COP is a value obtained by dividing the enthalpy difference in the condensation process or the evaporation process by the enthalpy difference in the compression process. That is, if the enthalpy difference in the condensation process or the evaporation process can be increased without increasing the enthalpy difference in the compression process, the COP is improved. The larger the target SC value, the larger the enthalpy difference in the condensation process. That is, the performance is improved by increasing the target SC value as much as possible. However, if the target SC value is too large (Δt*α<SC), it takes time for the SC value to reach the target SC. Since the opening degree of the expansion valve 28 decreases until the SC value reaches the target SC value, the density of the refrigerant flowing in the evaporator decreases, and the reliability of the compressor 21 decreases. Therefore, it is possible to select the SC value that has the best performance (for example, COP) as the air conditioner and that can secure the reliability of the compressor 21, and set it as the target SC value.
次に、図10に示すフローチャートを用いて、冷房運転を行う際に、室外機制御手段200のCPU210が実行する処理について説明する。なお、暖房運転を行う場合は、第1膨張弁24が上流側膨張弁となり、第2膨張弁が下流側膨張弁となる。
Next, the processing executed by the CPU 210 of the outdoor unit control means 200 when performing the cooling operation will be described using the flowchart shown in FIG. When performing the heating operation, the first expansion valve 24 serves as the upstream expansion valve and the second expansion valve serves as the downstream expansion valve.
図10に示すフローチャートは、CPU210が冷房運転を行う際の処理の流れを示すものであり、STはステップを表しこれに続く番号はステップ番号を表している。なお、図10では、本開示に関わる処理を中心に説明しており、これ以外の処理、例えば、使用者の指示した設定温度や風量等の運転条件に対応した冷媒回路10の制御といった、空気調和機1に関わる一般的な処理については説明を省略している。
The flow chart shown in FIG. 10 shows the flow of processing when the CPU 210 performs the cooling operation, and ST represents a step and the number following this represents a step number. Note that FIG. 10 mainly describes the processes related to the present disclosure, and processes other than this, for example, air control such as control of the refrigerant circuit 10 corresponding to operating conditions such as set temperature and air volume instructed by the user. The description of the general processing related to the harmony machine 1 is omitted.
CPU210は、冷房運転を開始すると、圧縮機21、上流側膨張弁(第2膨張弁28)、下流側膨張弁(第1膨張弁24)の起動制御を行う(ST101)。圧縮機21の起動制御は、圧縮機21からの吐油量を抑える目的で段階的に回転数を上昇させる制御である。第2膨張弁28及び第1膨張弁24の起動制御は、予め試験等で定められた外気温に応じた初期パルスが記憶部220にそれぞれ記憶されており、当該初期パルスで各々の開度を固定する制御である。次に、CPU210は、起動制御の終了条件(例えば、起動制御開始から10分経過)が成立したか否かを判定し(ST102)、終了条件が成立していれば(ST102-YES)、圧縮機21、第2膨張弁28、第1膨張弁24を通常制御に切り換える(ST103)。終了条件が成立していなければ(ST102-NO)、ST102に戻る。通常制御では、圧縮機21は要求コードに対応する回転数に制御、第2膨張弁28はSC制御、第1膨張弁24は吸入SH制御とする。ここで、要求コードとは、室内機3から室外機制御手段200の通信部を介して送られる信号である。例えば、要求コードは、冷房運転時において、室温センサ79の検出値である室内温度が空気調和機の設定温度に対して大きく上回っている場合、その差に応じて圧縮機21の回転数を大きくする値が設定される。
When the cooling operation is started, the CPU 210 controls the activation of the compressor 21, the upstream expansion valve (second expansion valve 28), and the downstream expansion valve (first expansion valve 24) (ST101). The startup control of the compressor 21 is a control in which the rotation speed is increased stepwise for the purpose of suppressing the amount of oil discharged from the compressor 21. In the startup control of the second expansion valve 28 and the first expansion valve 24, the initial pulse corresponding to the outside air temperature determined in advance in a test or the like is stored in the storage unit 220, and the opening degree of each of the initial pulses is set by the initial pulse. It is a fixed control. Next, the CPU 210 determines whether or not a termination condition for activation control (for example, 10 minutes have elapsed from the start of activation control) is satisfied (ST102), and if the termination condition is satisfied (ST102-YES), compression is performed. The machine 21, the second expansion valve 28, and the first expansion valve 24 are switched to normal control (ST103). If the ending condition is not satisfied (ST102-NO), the process returns to ST102. In the normal control, the compressor 21 is controlled to the rotation speed corresponding to the request code, the second expansion valve 28 is SC control, and the first expansion valve 24 is suction SH control. Here, the request code is a signal sent from the indoor unit 3 via the communication unit of the outdoor unit control means 200. For example, when the indoor temperature, which is the detection value of the room temperature sensor 79, greatly exceeds the set temperature of the air conditioner during the cooling operation, the request code increases the rotation speed of the compressor 21 in accordance with the difference. The value to be set is set.
次に、CPU210は、ST103の処理の後、図示しないカウンタのカウント値nに「2」を設定する。カウンタは、CPU210に設けられている。カウント値nは、後述する複数の目標SC値の切り替えに用いられる。本実施例では、図11Cに示すとおり、4つの目標値SCt(第1目標SC値、第2目標SC値、第3目標SC値、第4目標SC値)が記憶部220に記憶されている。カウント値nは、目標値の数に対応する数の値を有する。よって、カウント値nの最大値nmaxは「4」、最小値nmin「1」となる。なお、ST103において、カウンタのカウント値nを「2」に設定したが、他の値であっても良い。
Next, the CPU 210 sets "2" to the count value n of the counter (not shown) after the processing of ST103. The counter is provided in the CPU 210. The count value n is used for switching a plurality of target SC values described later. In the present embodiment, as shown in FIG. 11C, four target values SCt (first target SC value, second target SC value, third target SC value, fourth target SC value) are stored in the storage unit 220. .. The count value n has a number of values corresponding to the number of target values. Therefore, the maximum value nmax of the count value n is “4” and the minimum value nmin is “1”. Although the count value n of the counter is set to "2" in ST103, it may be another value.
次に、CPU210は、本ステップでは、Δt*α<第n目標SC値であるか否かを判定する(ST105)。ST103において、カウント値nに「2」を設定していたため、ここでは「Δt*α<第2目標SC値」が判定条件となる。係数αについては後述する。ST105の判定において、Δt*αが第n目標SC値未満であれば(ST105-YES)、CPU210は、nが最小値nminであるか否かを判定する(ST106)。nが最小値nminである場合(ST106-NO)、ST105の判定に戻る。nが最小値nminではない場合(ST106-YES)、目標SC値に第(n-1)目標SC値を設定する(ST107)。ここでは、目標SC値に第1目標SC値を設定する。そして、所定時間(例えば、10秒)が経過したか否かを判定し(ST108)、所定時間を経過しているときは(ST108-YES)、ST105の判定に戻る。所定時間を経過していないときは(ST108-NO)、ST108の判定を繰り返す。なお、所定時間は、本制御の制御間隔である。目標SC値SCtを変更した後、圧縮機21の回転数変化などで差Δtが変化する。このような場合に対応する目標SC値SCtに変更できるように、例えば、所定時間を10秒に設定して常時本制御を行えるようにしている。他方、ST105の判定において、Δt*αが第n目標SC値以下の場合(ST105-NO)、CPU210は、nが最大値nmaxであるか否かを判定する(ST109)。nが最大値nmaxである場合(ST109-NO)、ST105の判定に戻る。nが最大値nmaxではない場合(ST109-YES)、目標SC値を第(n+1)目標SC値に設定する(ST110)。ここでは、目標SC値に第3目標SC値を設定する。そして、ST108へ移行する。そして、所定時間(例えば、30秒)が経過したか否かを判定し(ST108)、所定時間を経過しているときは(ST108-YES)、ST105の判定に戻る。所定時間を経過していないときは(ST108-NO)、ST108の判定を繰り返す。
Next, in this step, the CPU 210 determines whether or not Δt*α<nth target SC value (ST105). Since the count value n is set to "2" in ST103, "Δt*α<second target SC value" is the determination condition here. The coefficient α will be described later. In the determination of ST105, if Δt*α is less than the nth target SC value (ST105-YES), the CPU 210 determines whether n is the minimum value nmin (ST106). When n is the minimum value nmin (ST106-NO), the process returns to the determination of ST105. When n is not the minimum value nmin (ST106-YES), the (n-1)th target SC value is set as the target SC value (ST107). Here, the first target SC value is set as the target SC value. Then, it is determined whether or not a predetermined time (for example, 10 seconds) has passed (ST108), and when the predetermined time has passed (ST108-YES), the process returns to the determination of ST105. When the predetermined time has not elapsed (ST108-NO), the determination of ST108 is repeated. The predetermined time is a control interval of this control. After changing the target SC value SCt, the difference Δt changes due to changes in the rotation speed of the compressor 21 and the like. In order to change the target SC value SCt corresponding to such a case, for example, the predetermined time is set to 10 seconds so that the main control can always be performed. On the other hand, in the determination of ST105, when Δt*α is equal to or smaller than the nth target SC value (ST105-NO), the CPU 210 determines whether n is the maximum value nmax (ST109). When n is the maximum value nmax (ST109-NO), the process returns to the determination of ST105. If n is not the maximum value nmax (ST109-YES), the target SC value is set to the (n+1)th target SC value (ST110). Here, the third target SC value is set as the target SC value. Then, the process proceeds to ST108. Then, it is determined whether or not a predetermined time (for example, 30 seconds) has elapsed (ST108), and when the predetermined time has elapsed (ST108-YES), the process returns to the determination of ST105. When the predetermined time has not elapsed (ST108-NO), the determination of ST108 is repeated.
1 空気調和機
2 室外機
3 室内機
4 液管
5 ガス管
10 冷媒回路
10a 室外機冷媒回路
10b 室内機冷媒回路
21 圧縮機
22 四方弁
23 室外熱交換器
24 (暖房運転時)上流側膨張弁
25 液側閉鎖弁
26 ガス側閉鎖弁
27 室外ファン
28 (暖房運転時)下流側膨張弁
29 インジェクション膨張弁
31 室内熱交換器
32 室内ファン
33 液管接続部
34 ガス管接続部
61 吐出管(圧縮機~四方弁)
62 冷媒配管(四方弁~室外熱交換器)
63 室外機液管(室外熱交換器~液側閉鎖弁)
64 室外機ガス管(ガス側閉鎖弁~四方弁)
65 インジェクション配管(中圧レシーバ、冷媒間熱交換器~圧縮機)
66 吸入管(四方弁~圧縮機)
67 室内機液管(液側閉鎖弁~室内熱交換器)
68 室内機ガス管(室内熱交換器~ガス側閉鎖弁)
71 吐出圧力センサ
72 吸入圧力センサ
73 吐出温度センサ
74 吸入温度センサ
75 熱交温度センサ
76 外気温度センサ
77a 液側温度センサ
77b 室外機液管温度センサ
78 ガス側温度センサ
79 室温センサ
81 中圧レシーバ
82 冷媒間熱交換器
200 室外機制御手段
210 CPU
220 記憶部
230 通信部
240 センサ入力部 1air conditioner 2 outdoor unit 3 indoor unit 4 liquid pipe 5 gas pipe 10 refrigerant circuit 10a outdoor unit refrigerant circuit 10b indoor unit refrigerant circuit 21 compressor 22 four-way valve 23 outdoor heat exchanger 24 (during heating operation) upstream expansion valve 25 Liquid side closing valve 26 Gas side closing valve 27 Outdoor fan 28 (during heating operation) Downstream expansion valve 29 Injection expansion valve 31 Indoor heat exchanger 32 Indoor fan 33 Liquid pipe connection 34 Gas pipe connection 61 Discharge pipe (compression) Machine-four-way valve)
62 Refrigerant piping (four-way valve to outdoor heat exchanger)
63 Outdoor unit liquid pipe (outdoor heat exchanger to liquid side closing valve)
64 Outdoor unit gas pipe (gas-side closing valve-four-way valve)
65 injection piping (intermediate pressure receiver, refrigerant heat exchanger to compressor)
66 Suction pipe (four-way valve-compressor)
67 Indoor unit liquid pipe (liquid side closing valve-indoor heat exchanger)
68 Indoor unit gas pipe (indoor heat exchanger to gas side closing valve)
71Discharge pressure sensor 72 Suction pressure sensor 73 Discharge temperature sensor 74 Suction temperature sensor 75 Heat exchange temperature sensor 76 Outside air temperature sensor 77a Liquid side temperature sensor 77b Outdoor unit liquid pipe temperature sensor 78 Gas side temperature sensor 79 Room temperature sensor 81 Medium pressure receiver 82 Heat exchanger between refrigerants 200 Outdoor unit control means 210 CPU
220storage unit 230 communication unit 240 sensor input unit
2 室外機
3 室内機
4 液管
5 ガス管
10 冷媒回路
10a 室外機冷媒回路
10b 室内機冷媒回路
21 圧縮機
22 四方弁
23 室外熱交換器
24 (暖房運転時)上流側膨張弁
25 液側閉鎖弁
26 ガス側閉鎖弁
27 室外ファン
28 (暖房運転時)下流側膨張弁
29 インジェクション膨張弁
31 室内熱交換器
32 室内ファン
33 液管接続部
34 ガス管接続部
61 吐出管(圧縮機~四方弁)
62 冷媒配管(四方弁~室外熱交換器)
63 室外機液管(室外熱交換器~液側閉鎖弁)
64 室外機ガス管(ガス側閉鎖弁~四方弁)
65 インジェクション配管(中圧レシーバ、冷媒間熱交換器~圧縮機)
66 吸入管(四方弁~圧縮機)
67 室内機液管(液側閉鎖弁~室内熱交換器)
68 室内機ガス管(室内熱交換器~ガス側閉鎖弁)
71 吐出圧力センサ
72 吸入圧力センサ
73 吐出温度センサ
74 吸入温度センサ
75 熱交温度センサ
76 外気温度センサ
77a 液側温度センサ
77b 室外機液管温度センサ
78 ガス側温度センサ
79 室温センサ
81 中圧レシーバ
82 冷媒間熱交換器
200 室外機制御手段
210 CPU
220 記憶部
230 通信部
240 センサ入力部 1
62 Refrigerant piping (four-way valve to outdoor heat exchanger)
63 Outdoor unit liquid pipe (outdoor heat exchanger to liquid side closing valve)
64 Outdoor unit gas pipe (gas-side closing valve-four-way valve)
65 injection piping (intermediate pressure receiver, refrigerant heat exchanger to compressor)
66 Suction pipe (four-way valve-compressor)
67 Indoor unit liquid pipe (liquid side closing valve-indoor heat exchanger)
68 Indoor unit gas pipe (indoor heat exchanger to gas side closing valve)
71
220
Claims (2)
- 冷媒が、圧縮機、凝縮器、凝縮側膨張弁、中圧レシーバ、蒸発側膨張弁、蒸発器の順に流れるように冷媒配管で接続された冷媒回路と、
前記凝縮側膨張弁及び前記蒸発側膨張弁を制御する制御手段と、
凝縮温度を検出する凝縮温度センサと、前記凝縮器から流出した冷媒の温度である凝縮器出口温度を検出する凝縮器出口温度センサと、前記凝縮器の周囲温度を検出する凝縮器周囲温度センサと、を備え、
前記制御手段は、前記凝縮温度と前記凝縮器出口温度の差であるSC値が目標値SCtとなるように前記凝縮側膨張弁の開度を制御するSC制御を行い、
前記制御手段は、前記凝縮温度と前記周囲温度の差Δtに応じて、前記目標値SCtを変更する、
空気調和機。 Refrigerant, a refrigerant circuit connected by a refrigerant pipe so that the compressor, the condenser, the condensation side expansion valve, the intermediate pressure receiver, the evaporation side expansion valve, the evaporator flow in order,
Control means for controlling the condensation side expansion valve and the evaporation side expansion valve,
A condensing temperature sensor for detecting a condensing temperature, a condenser outlet temperature sensor for detecting a condenser outlet temperature which is a temperature of a refrigerant flowing out from the condenser, and a condenser ambient temperature sensor for detecting an ambient temperature of the condenser. ,,
The control means performs SC control for controlling the opening degree of the condensation side expansion valve such that the SC value, which is the difference between the condensation temperature and the condenser outlet temperature, becomes a target value SCt.
The control means changes the target value SCt according to a difference Δt between the condensation temperature and the ambient temperature,
Air conditioner. - 前記目標値SCtは、前記差Δtに応じて複数設けられており、前記差Δtが大きい程目標値SCtも大きい値が設定される、
請求項1に記載の空気調和機。 A plurality of target values SCt are provided according to the difference Δt, and a larger target value SCt is set as the difference Δt is larger.
The air conditioner according to claim 1.
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WO2009047906A1 (en) * | 2007-10-10 | 2009-04-16 | Daikin Industries, Ltd. | Air conditioner |
JP2011007482A (en) * | 2009-05-29 | 2011-01-13 | Daikin Industries Ltd | Air conditioner |
JP2012211723A (en) * | 2011-03-31 | 2012-11-01 | Nakano Refrigerators Co Ltd | Freezer and method for detecting refrigerant leakage in the freezer |
JP2013164251A (en) * | 2012-02-13 | 2013-08-22 | Panasonic Corp | Refrigerating apparatus |
JP2014167381A (en) * | 2013-01-29 | 2014-09-11 | Daikin Ind Ltd | Air conditioning device |
JP2015068614A (en) * | 2013-09-30 | 2015-04-13 | ダイキン工業株式会社 | Refrigeration unit |
JP2017075760A (en) * | 2015-10-16 | 2017-04-20 | ダイキン工業株式会社 | Air conditioner |
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WO2009047906A1 (en) * | 2007-10-10 | 2009-04-16 | Daikin Industries, Ltd. | Air conditioner |
JP2011007482A (en) * | 2009-05-29 | 2011-01-13 | Daikin Industries Ltd | Air conditioner |
JP2012211723A (en) * | 2011-03-31 | 2012-11-01 | Nakano Refrigerators Co Ltd | Freezer and method for detecting refrigerant leakage in the freezer |
JP2013164251A (en) * | 2012-02-13 | 2013-08-22 | Panasonic Corp | Refrigerating apparatus |
JP2014167381A (en) * | 2013-01-29 | 2014-09-11 | Daikin Ind Ltd | Air conditioning device |
JP2015068614A (en) * | 2013-09-30 | 2015-04-13 | ダイキン工業株式会社 | Refrigeration unit |
JP2017075760A (en) * | 2015-10-16 | 2017-04-20 | ダイキン工業株式会社 | Air conditioner |
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