Air conditioner

Abstract

To suppress deterioration of operation efficiency in a medium load region.SOLUTION: An air conditioner includes a first compressor 101 which is driven by a gas engine 103, a power generator 123 which is driven by the gas engine 103, a second compressor 102 which is driven by an electric motor 104, an exhaust heat recovery heat exchanger 115 which heats a refrigerant with exhaust heat of the gas engine 103, a first outlet pipe 119 which returns the refrigerant passing through the exhaust heat recovery heat exchanger 115 to a suction pipe of the first compressor 101 and a suction pipe of the second compressor 102, a second outlet pipe 120 which returns the refrigerant passing through the exhaust heat recovery heat exchanger 115 to the suction pipe of the second compressor 102, and a control unit 40 which changes a driving source of the compressor in accordance with a load request of air conditioning. The control unit 40 drives the first compressor 101, the second compressor 102, and the power generator 123 in a medium load region during heating operation.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an air conditioning apparatus. [Background technology]

[0002] Patent Document 1 discloses an air conditioner including a compressor driven by a gas engine, a compressor driven by an electric motor, and a waste heat recovery heat exchanger that heats a refrigerant with waste heat from the gas engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-56944 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides an air conditioner that suppresses a decrease in operational efficiency in the medium load range during heating operation. [Means for solving the problem]

[0005] The air conditioning apparatus of the present disclosure comprises a first compressor driven by a gas engine, a generator driven by the gas engine, a second compressor driven by an electric motor, a heat recovery heat exchanger that heats a refrigerant with exhaust heat from the gas engine, a first outlet pipe that returns the refrigerant that has passed through the heat recovery heat exchanger to the suction pipe of the first compressor and the suction pipe of the second compressor, a second outlet pipe that returns the refrigerant that has passed through the heat recovery heat exchanger to the suction pipe of the second compressor, and a control unit that changes the driving source in accordance with the air conditioning load requirement, and the control unit drives the first compressor, the second compressor, and the generator when the load is in the medium load range during heating operation. Effect of the Invention

[0006] In the air conditioner according to the present disclosure, when in a medium load range during heating operation, the amount of exhaust heat from the gas engine is increased, and a portion of the medium-temperature, medium-pressure refrigerant that has undergone exhaust heat recovery is drawn into the compressor driven by the electric motor, and the remaining refrigerant is drawn into the compressor driven by the gas engine. Therefore, the air conditioner according to the present disclosure can suppress a decrease in operating efficiency in the medium load range. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a configuration diagram showing an air conditioner during cooling operation in a first embodiment. [Diagram 2] FIG. 1 is a configuration diagram showing an air conditioner during heating operation in a first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (The knowledge and other information that formed the basis of this disclosure) At the time when the inventors came up with the present disclosure, there was a technology related to an air conditioner including a compressor driven by a gas engine, a compressor driven by an electric motor, and a heat recovery heat exchanger that heats a refrigerant with the exhaust heat of the gas engine. In this technology, in the case of medium load or more in heating operation, the outdoor heat exchanger pumps heat from the air while heating the refrigerant using the exhaust heat of the gas engine, and the heated refrigerant is sucked into the compressor driven by the electric motor, so that highly efficient operation is possible. However, in the medium load region, the driving range of the compressor driven by the electric motor is limited because the driving of the compressor driven by the electric motor depends on the amount of exhaust heat of the gas engine, and when the rotation speed of the gas engine is reduced, the amount of exhaust heat of the gas engine is reduced, and as a result, the operating ratio of the compressor driven by the gas engine increases, and the efficiency of the air conditioner decreases. The inventors discovered a problem that the subject of the present disclosure was constituted in order to solve the problem. Therefore, the present disclosure provides an air conditioner that suppresses a decrease in operating efficiency in the medium load range during heating operation.

[0009] Hereinafter, the embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming more redundant than necessary and to facilitate understanding by those skilled in the art. It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0010] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIG. [1-1. Configuration] 1 is a diagram showing the configuration of an air conditioner 1 in a first embodiment of the present disclosure. The air conditioner 1 includes a first compressor 101 driven by a gas engine 103, a generator 123 driven by the gas engine 103, and a second compressor 102 connected in parallel to the first compressor 101 and driven by an electric motor 104. The first compressor 101 has a larger capacity than the second compressor 102. The air conditioner 1 comprises an outdoor unit 10 and an indoor unit 20, and these units 10, 20 are connected by a liquid pipe 31 and a gas pipe 32. A plurality of indoor units 20 may be installed in parallel with the outdoor unit 10.

[0011] The outdoor unit 10 includes an oil separator 105, a four-way valve 106, an outdoor heat exchanger 107, a radiator 114, an outdoor fan 108, and an outdoor expansion valve 109 on the discharge side of the compressors 101 and 102. The radiator 114 is disposed downwind of the outdoor heat exchanger 107, and dissipates heat from the engine coolant by the outdoor fan 108.

[0012] The outdoor expansion valve 109 is connected to an indoor heat exchanger 201 of the indoor unit 20 via a liquid pipe 31, and the indoor heat exchanger 201 is connected to the four-way valve 106 of the outdoor unit 10. The indoor unit 20 is equipped with an indoor fan 202 and an indoor expansion valve 203. The outdoor unit 10 is equipped with a low-pressure gas pipe 113 connected to the four-way valve 106, an accumulator 110, a low-pressure gas pipe 124, a first compressor suction pipe 111, and a second compressor suction pipe 112 on the suction side of the compressors 101 and 102.

[0013] The outdoor unit 10 is provided with a branch pipe branching off from the liquid pipe 31 downstream of the outdoor expansion valve 109, and this branch pipe is connected to the exhaust heat recovery expansion valve 116, the exhaust heat recovery heat exchanger 115, and the three-way switching valve 117. The exhaust of the gas engine 103 is supplied to the exhaust heat recovery heat exchanger 115 via the exhaust heat transfer section 125. The exhaust heat transfer section 125 may be configured, for example, as a pipe that directly guides the exhaust of the gas engine 103 to the exhaust heat recovery heat exchanger 115, or may be configured as a pipe that guides the cooling water heated by the gas engine 103 to the exhaust heat recovery heat exchanger 115 to indirectly transfer heat. The three-way switching valve 117 is connected to the outlet of the exhaust heat recovery heat exchanger 115 via a bypass pipe 118. The bypass pipe 118 connects the liquid pipe 31 and the three-way switching valve 117.

[0014] One outlet of the three-way switching valve 117 is connected to a first outlet pipe 119 via a pressure regulating valve 121. The pressure regulating valve 121 adjusts the flow rate of the refrigerant flowing through the first outlet pipe 119. The first outlet pipe 119 is connected to the first compressor suction pipe 111 via a low-pressure gas pipe 113, an accumulator 110, and a low-pressure gas pipe 124. A second outlet pipe 120 is connected to the other outlet of the three-way switching valve 117. The second outlet pipe 120 is connected to a second compressor suction pipe 112 that connects the suction port of the second compressor 102 and a check valve 122. The check valve 122 prevents the refrigerant flowing from the second outlet pipe 120 into the second compressor suction pipe 112 from flowing back toward the first compressor suction pipe 111.

[0015] Depending on the load during heating and cooling operation, the three-way switching valve 117 switches so that the refrigerant flowing in from the bypass pipe 118 flows toward the first outlet pipe 119, or toward the second outlet pipe 120, or toward both the first outlet pipe 119 and the second outlet pipe 120. Although details will be described later, the three-way switching valve 117 causes the refrigerant flowing in from the bypass pipe 118 to flow out to the second outlet pipe 120 in a high load region, and to flow out to both the first outlet pipe 119 and the second outlet pipe 120 in a medium load region.

[0016] The air conditioner 1 is equipped with a control unit 40. The control unit 40 controls the driving of the first compressor 101 and the second compressor 102, switching between cooling operation and heating operation, and switching of the exhaust heat recovery expansion valve 116, the three-way switching valve 117, and the pressure regulating valve 121 according to the magnitude of the load required in the cooling operation and the heating operation.

[0017] [1-2. Operation] Next, the cooling operation and heating operation of the air conditioner 1 will be explained according to the magnitude of the required load.

[0018] (Low load cooling range) FIG. 1 is a diagram of the refrigerant circuit during cooling operation. In the low load region of the cooling operation, the control unit 40 drives only the second compressor 102 driven by the electric motor 104, and closes the exhaust heat recovery expansion valve 116. The control unit 40 sets the four-way valve 106 to the cooling operation position indicated by the dotted line.

[0019] The high-temperature, high-pressure gas refrigerant compressed by the second compressor 102 passes through the oil separator 105 and the four-way valve 106 and enters the outdoor heat exchanger 107. The gas refrigerant exchanges heat with the outside air in the outdoor heat exchanger 107, dissipates heat, and then condenses to become a medium-temperature, high-pressure liquid refrigerant. The medium-temperature, high-pressure liquid refrigerant passes through the outdoor expansion valve 109 and the liquid pipe 31 and becomes a low-temperature, low-pressure liquid refrigerant, which is supplied to the indoor unit 20. The low-temperature, low-pressure liquid refrigerant that has entered the indoor unit 20 is decompressed by the indoor expansion valve 203, becomes a low-temperature, low-pressure two-phase gas-liquid refrigerant, and flows into the indoor heat exchanger 201. The refrigerant in the two-phase gas-liquid state exchanges heat with the indoor air in the indoor heat exchanger 201, absorbs heat, and then evaporates, becoming a low-temperature, low-pressure gas refrigerant and flowing out of the indoor unit 20.

[0020] The gas refrigerant flowing out of the indoor unit 20 passes through the gas pipe 32 and returns to the outdoor unit 10. The gas refrigerant flowing into the outdoor unit 10 passes through the four-way valve 106, the low-pressure gas pipe 113, the accumulator 110, the low-pressure gas pipe 124, and the second compressor suction pipe 112, and is returned to the second compressor 102.

[0021] (Cooling operation high load range) In the high load region of cooling operation, the control unit 40 drives both the first compressor 101 driven by the gas engine 103 and the second compressor 102 driven by the electric motor 104. The control unit 40 opens the exhaust heat recovery expansion valve 116 and sets the outlet of the three-way switching valve 117 to the direction only of the second outlet pipe 120.

[0022] The high-temperature, high-pressure refrigerant compressed by the first compressor 101 and the second compressor 102 passes through an oil separator 105 and a four-way valve 106, and enters an outdoor heat exchanger 107. The gas refrigerant exchanges heat with outside air in the outdoor heat exchanger 107, and becomes a medium-temperature, high-pressure liquid refrigerant. The medium-temperature, high-pressure liquid refrigerant passes through an outdoor expansion valve 109, and becomes a low-temperature, low-pressure liquid refrigerant.

[0023] This low-temperature, low-pressure liquid refrigerant passes through the liquid pipe 31 and flows into the indoor unit 20. The low-temperature, low-pressure liquid refrigerant that has entered the indoor unit 20 is decompressed by the indoor expansion valve 203 and flows into the indoor heat exchanger 201. The refrigerant in a two-phase gas-liquid state exchanges heat with the indoor air in the indoor heat exchanger 201, absorbs heat, and then evaporates, becoming a low-temperature, low-pressure gas refrigerant that flows out of the indoor unit 20. This gas refrigerant passes through the gas pipe 32 and is returned to the outdoor unit 10. This gas refrigerant passes through the four-way valve 106, the accumulator 110, and the low-pressure gas pipe 124, and is then branched, and flows into the first compressor suction pipe 111 and the second compressor suction pipe 112. The refrigerant that passed through the first compressor suction pipe 111 is returned to the first compressor 101.

[0024] The exhaust heat of the gas engine 103 is transported to the radiator 114 where it is exchanged with the outside air, and the engine cooling water is returned to the gas engine 103.

[0025] In this embodiment, in the (high-load cooling operation region), a portion of the low-temperature, low-pressure liquid refrigerant passing through liquid pipe 31 flows into bypass pipe 118 as indicated by the dotted arrow. The low-temperature, low-pressure liquid refrigerant that has flowed into the bypass pipe 118 is decompressed by the exhaust heat recovery expansion valve 116 and flows into the exhaust heat recovery heat exchanger 115. The refrigerant in a gas-liquid two-phase state absorbs the exhaust heat transferred from the gas engine 103 through the exhaust heat transfer section 125, and then evaporates to become a medium-temperature, medium-pressure gas refrigerant. The refrigerant then flows into the three-way switching valve 117. The medium-temperature, medium-pressure gas refrigerant flows out from the outlet of the three-way switching valve 117 to the second outlet pipe 120 , and passes through the second outlet pipe 120 to flow into the second compressor suction pipe 112 .

[0026] The medium-temperature and medium-pressure gas refrigerant flows into the second compressor suction pipe 112 from the second outlet pipe 120 side, and the low-temperature and low-pressure gas refrigerant flows into the second compressor suction pipe 112 from the low-pressure gas pipe 124 side. Therefore, the medium-temperature and medium-pressure gas refrigerant, which has a lower temperature and pressure than the refrigerant flowing in from the second outlet pipe 120 side, is returned to the second compressor 102.

[0027] (Cooling operation medium load area) In the medium load region of cooling operation, the control unit 40 drives the first compressor 101 driven by the gas engine 103 and closes the exhaust heat recovery expansion valve 116. In this case, the drive of the second compressor 102 driven by the electric motor 104 is stopped.

[0028] The high-temperature, high-pressure gas refrigerant compressed by the first compressor 101 passes through an oil separator 105 and a four-way valve 106, and enters an outdoor heat exchanger 107. The gas refrigerant becomes a medium-temperature, high-pressure liquid refrigerant in the outdoor heat exchanger 107, passes through an outdoor expansion valve 109 and a liquid pipe 31, and is supplied to the indoor unit 20 as a low-temperature, low-pressure liquid refrigerant.

[0029] The low-temperature, low-pressure liquid refrigerant that has entered the indoor unit 20 is decompressed by the indoor expansion valve 203 and flows into the indoor heat exchanger 201 . The refrigerant in a two-phase gas-liquid state exchanges heat with the indoor air in the indoor heat exchanger 201, absorbs heat, and then evaporates, becoming a low-temperature, low-pressure gas refrigerant, which flows out of the indoor unit 20. This gas refrigerant passes through the gas pipe 32 and returns to the outdoor unit 10. The gas refrigerant that has flowed into the outdoor unit 10 passes through the four-way valve 106 , the low-pressure gas pipe 113 , the accumulator 110 , the low-pressure gas pipe 124 and the first compressor suction pipe 111 , and is returned to the first compressor 101 .

[0030] The cooling water for the gas engine 103 is transported by the exhaust heat transfer section 125 to the radiator 114 , where it exchanges heat with the outside air and is returned to the gas engine 103 .

[0031] (Heating operation low load range) FIG. 2 shows the refrigerant circuit during heating operation. In the low load region of the heating operation, similarly to the low load region of the cooling operation, the control unit 40 drives only the second compressor 102 using the electric motor 104 as a drive source, and closes the exhaust heat recovery expansion valve 116. The control unit 40 sets the four-way valve 106 to the heating operation position indicated by the solid line.

[0032] The high-temperature, high-pressure refrigerant compressed by the second compressor 102 passes through an oil separator 105 and a four-way valve 106 and is supplied to the indoor unit 20.

[0033] The high-temperature, high-pressure gas refrigerant that has entered the indoor unit 20 flows into the indoor heat exchanger 201, exchanges heat with the indoor air, and becomes a medium-temperature, high-pressure liquid refrigerant. The medium-temperature, high-pressure liquid refrigerant passes through the indoor expansion valve 203 and the liquid pipe 31, becomes a low-temperature, low-pressure liquid refrigerant, and is returned to the outdoor unit 10. This low-temperature, low-pressure liquid refrigerant is depressurized by the outdoor expansion valve 109 and flows into the outdoor heat exchanger 107. The refrigerant in a gas-liquid two-phase state exchanges heat with the outdoor air in the outdoor heat exchanger 107, absorbs heat, and then evaporates, becoming a low-temperature, low-pressure gas refrigerant. This low-temperature, low-pressure gas refrigerant passes through the four-way valve 106, the low-pressure gas pipe 113, the accumulator 110, the low-pressure gas pipe 124, and the second compressor suction pipe 112, and is returned to the second compressor 102.

[0034] (Heating operation high load range) In the high load region of the heating operation, the control unit 40 drives both the first compressor 101 driven by the gas engine 103 and the second compressor 102 driven by the electric motor 104. The control unit 40 opens the exhaust heat recovery expansion valve 116, closes the pressure regulating valve 121, and sets the outlet of the three-way switching valve 117 to only the second outlet pipe 120.

[0035] The high-temperature, high-pressure refrigerant compressed by the first compressor 101 and the second compressor 102 passes through an oil separator 105 and a four-way valve 106 and is supplied to the indoor unit 20.

[0036] The high-temperature, high-pressure gas refrigerant that has entered the indoor unit 20 flows into the indoor heat exchanger 201, where it exchanges heat with the indoor air, dissipates heat, and then condenses to become a medium-temperature, high-pressure liquid refrigerant. The medium-temperature, high-pressure liquid refrigerant passes through the indoor expansion valve 203, becomes a low-temperature, low-pressure liquid refrigerant, and is returned to the outdoor unit 10. This low-temperature, low-pressure liquid refrigerant is depressurized by the outdoor expansion valve 109 and flows into the outdoor heat exchanger 107. The refrigerant in a gas-liquid two-phase state exchanges heat with the outside air in the outdoor heat exchanger 107, absorbs heat, and then evaporates, becoming a low-temperature, low-pressure gas refrigerant. This low-temperature, low-pressure gas refrigerant passes through four-way valve 106, low-pressure gas pipe 113, accumulator 110 and low-pressure gas pipe 124, and a portion of it flows into first compressor suction pipe 111 and the remainder flows into second compressor suction pipe 112.

[0037] The exhaust heat of the gas engine 103 is transported to the radiator 114 and exchanged with the outside air, and the engine cooling water is returned to the gas engine 103.

[0038] A portion of the low-temperature, low-pressure liquid refrigerant flowing through the liquid pipe 31 toward the outdoor heat exchanger 107 flows into the bypass pipe 118 as indicated by the dotted arrow, is depressurized by the exhaust heat recovery expansion valve 116, and flows into the exhaust heat recovery heat exchanger 115. The refrigerant in the gas-liquid two-phase state exchanges heat with the exhaust heat transferred from the gas engine 103 through the exhaust heat transfer section 125 in the exhaust heat recovery heat exchanger 115, absorbs heat, and then evaporates, becoming a medium-temperature, medium-pressure gas refrigerant and flowing to the three-way switching valve 117. Since the outlet of the three-way switching valve 117 is set only to the second outlet pipe 120, the medium-temperature and medium-pressure gas refrigerant flows from the outlet of the three-way switching valve 117 through the second outlet pipe 120 into the second compressor suction pipe 112.

[0039] The medium-temperature and medium-pressure gas refrigerant flows into the second compressor suction pipe 112 from the second outlet pipe 120 side, and the low-temperature and low-pressure gas refrigerant flows into the second compressor suction pipe 112 from the low-pressure gas pipe 124 side. Therefore, the medium-temperature and medium-pressure gas refrigerant, which has a lower temperature and pressure than the refrigerant flowing in from the second outlet pipe 120 side, is returned to the second compressor 102.

[0040] As described above, in the present embodiment, in the heating operation high load region, the outlet of the three-way switching valve 117 is set only on the second outlet pipe 120 side, so that the refrigerant that has undergone exhaust heat recovery in the exhaust heat recovery heat exchanger 115 is drawn in a medium-temperature and medium-pressure state only into the second compressor 102. As a result, since medium-temperature and medium-pressure gas refrigerant is drawn into the second compressor 102, the compression ratio of the gas refrigerant in the second compressor 102 can be made smaller than the case in which the low-temperature and low-pressure gas refrigerant flowing in the low-pressure gas pipe 113 is compressed.

[0041] (Heating operation load range) In the medium load region of heating operation, the control unit 40 drives both the first compressor 101 driven by the gas engine 103 and the second compressor 102 driven by the electric motor 104, as in the high load region of heating operation. Furthermore, the control unit 40 drives the generator 123 by the gas engine 103. In addition, the control unit 40 opens the exhaust heat recovery expansion valve 116 and the pressure regulating valve 121, and sets the outlet of the three-way switching valve 117 to two directions, the first outlet pipe 119 and the second outlet pipe 120.

[0042] The high-temperature, high-pressure refrigerant compressed by the first compressor 101 and the second compressor 102 passes through an oil separator 105 and a four-way valve 106 and is supplied to the indoor unit 20.

[0043] The high-temperature, high-pressure gas refrigerant that enters the indoor unit 20 flows into the indoor heat exchanger 201, where it exchanges heat with the indoor air, dissipates heat, and then condenses to become a medium-temperature, high-pressure liquid refrigerant. The medium-temperature, high-pressure liquid refrigerant passes through the indoor expansion valve 203 and liquid pipe 31, becomes a low-temperature, low-pressure liquid refrigerant, and is returned to the outdoor unit 10. The low-temperature, low-pressure liquid refrigerant that flows into the outdoor unit 10 is depressurized by the outdoor expansion valve 109 and flows into the outdoor heat exchanger 107. The refrigerant in a gas-liquid two-phase state exchanges heat with the outside air in the outdoor heat exchanger 107, absorbs heat, and then evaporates to become a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant flowing out of the outdoor heat exchanger 107 passes through the four-way valve 106, the low-pressure gas pipe 113, the accumulator 110 and the low-pressure gas pipe 124, with a portion of it flowing into the first compressor suction pipe 111 and the remainder flowing into the second compressor suction pipe 112.

[0044] The exhaust heat of the gas engine 103 is transported to the radiator 114 and exchanged with the outside air, and the cooling water is returned to the gas engine 103.

[0045] A portion of the low-temperature, low-pressure liquid refrigerant flowing through the liquid pipe 31 toward the outdoor heat exchanger 107 flows into the bypass pipe 118, as indicated by the dashed arrow, and is reduced in pressure by the exhaust heat recovery expansion valve 116 and flows into the exhaust heat recovery heat exchanger 115. The refrigerant in a gas-liquid two-phase state exchanges heat with the exhaust heat transferred from the gas engine 103 through the exhaust heat transfer section 125 in the exhaust heat recovery heat exchanger 115, absorbs heat, and then evaporates, becoming a medium-temperature / medium-pressure gas refrigerant and flowing to the three-way switching valve 117. A portion of the medium-temperature / medium-pressure gas refrigerant is depressurized by the pressure regulating valve 121 connected to the first outlet pipe 119, becoming a low-temperature / low-pressure gas refrigerant and flowing into the low-pressure gas pipe 113. On the other hand, the remainder of the medium-temperature / medium-pressure gas refrigerant flows from the outlet of the three-way switching valve 117 through the second outlet pipe 120 into the second compressor suction pipe 112.

[0046] The medium-temperature and medium-pressure gas refrigerant flows into the second compressor suction pipe 112 from the second outlet pipe 120 side, and the low-temperature and low-pressure gas refrigerant flows into the second compressor suction pipe 112 from the low-pressure gas pipe 124 side. Therefore, the medium-temperature and medium-pressure gas refrigerant, which has a lower temperature and pressure than the refrigerant flowing in from the second outlet pipe 120 side, is returned to the second compressor 102.

[0047] In the heating operation medium load region, the rotation speed of the gas engine 103 that drives the first compressor 101 is controlled in a low speed region, as compared with the heating operation high load region described above. Since the operation of the second compressor 102 driven by the electric motor 104 depends on the amount of exhaust heat from the gas engine 103, when the rotation speed of the gas engine 103 decreases and the amount of exhaust heat decreases, the operating range of the second compressor 102 driven by the electric motor 104 is restricted. As a result, the operating ratio of the first compressor 101 driven by the gas engine 103 increases, and the efficiency of the air conditioning device 1 decreases.

[0048] In this embodiment, in the heating operation load region, the first compressor 101 and the second compressor 102 are driven while the gas engine 103 drives the generator 123, so that a decrease in the amount of exhaust heat from the gas engine 103 is suppressed. As a result, a decrease in the operation ratio of the second compressor 102 driven by the electric motor 104 is suppressed, and the efficiency of the air conditioner 1 is improved.

[0049] In this embodiment, in the heating operation medium load region, the outlet of the three-way switching valve 117 is set to two directions, that is, to the first outlet pipe 119 and the second outlet pipe 120 . As a result, since a medium-temperature and medium-pressure gas refrigerant is drawn into the second compressor 102, the compression ratio of the gas refrigerant in the second compressor 102 can be made smaller than that in the case of compressing a low-temperature, low-pressure gas refrigerant flowing in the low-pressure gas pipe 113. Furthermore, a portion of the refrigerant drawn into the first compressor 101 can also be used to recover exhaust heat from the gas engine 103. In other words, even during heating operation under medium load, the amount of exhaust heat from the gas engine 103 is improved, and the driving range of the second compressor 102 driven by the electric motor 104 is expanded without being restricted, making it possible to operate with high efficiency even in the medium load range.

[0050] (Additional Note) The above description of the embodiments discloses the following techniques. (Technology 1) An air-conditioning apparatus comprising: a first compressor driven by a gas engine; a generator driven by the gas engine; a second compressor driven by an electric motor; a heat recovery heat exchanger that heats a refrigerant with exhaust heat from the gas engine; a first outlet pipe that returns the refrigerant that has passed through the heat recovery heat exchanger to a suction pipe of the first compressor and a suction pipe of the second compressor; a second outlet pipe that returns the refrigerant that has passed through the heat recovery heat exchanger to a suction pipe of the second compressor; and a control unit that changes a drive source of the compressor in response to an air-conditioning load request, wherein the control unit drives the first compressor, the second compressor, and the generator when the load is in the medium range during heating operation. In this technology 1, during heating operation, in the medium load range, the first compressor, the second compressor, and the generator are driven, so that the reduction in the amount of exhaust heat from the gas engine is suppressed by the amount of driving the generator, and the driving range of the second compressor driven by the electric motor is expanded without being restricted, enabling highly efficient operation.

[0051] (Technical 2) The air conditioner according to Technical 1, wherein the first compressor has a larger capacity than the second compressor.

[0052] (Technology 3) The control unit, during heating operation, in a high load region, drives the first compressor and the second compressor, and returns the refrigerant that has passed through the exhaust heat recovery heat exchanger to the suction pipe of the second compressor via the second outlet pipe, and in a medium load region, drives the first compressor, the second compressor, and the generator, and returns a portion of the refrigerant that has passed through the exhaust heat recovery heat exchanger to the suction pipe of the second compressor via the second outlet pipe, and returns the remainder to the suction pipe of the first compressor via the first outlet pipe, in the air conditioning apparatus described in Technology 1. As a result of this technology 3, since medium-temperature and medium-pressure gas refrigerant is drawn into the second compressor, the compression ratio of the gas refrigerant in the second compressor can be made smaller than when compressing low-temperature, low-pressure gas refrigerant flowing in a low-pressure gas pipe, and a portion of the refrigerant drawn into the first compressor can also be used to recover exhaust heat from the gas engine. In other words, even during heating operation under load, the amount of exhaust heat from the gas engine is improved, and the driving range of the second compressor driven by the electric motor is expanded rather than restricted, enabling highly efficient operation.

[0053] (Technology 4) The air conditioning apparatus described in Technology 3, wherein the control unit, in the case of a high load region, returns the refrigerant to the suction pipe of the second compressor at medium temperature and medium pressure, and in the case of a medium load region, returns a portion of the refrigerant to the suction pipe of the second compressor at medium temperature and medium pressure, and returns the remainder to the suction pipe of the first compressor at low temperature and low pressure. With this technology 4, even in the medium load range of heating operation, the amount of exhaust heat from the gas engine is increased, and the driving range of the second compressor driven by the electric motor is expanded rather than restricted, enabling highly efficient operation.

[0054] (Technology 5) An air conditioning apparatus according to any one of Technologies 1 to 4, further comprising a three-way switching valve at the outlet of the exhaust heat recovery heat exchanger, the first outlet pipe being connected to one outlet of the three-way switching valve, and the second outlet pipe being connected to the other outlet of the three-way switching valve. In this technique 5, switching is performed by a three-way switching valve, so the configuration is simplified.

[0055] (Technical Technique 6) The air conditioning apparatus according to Technical Technique 4, further comprising a pressure regulating valve disposed in the first outlet pipe. In this technique 6, the refrigerant can be returned to the suction pipe of the first compressor at a low temperature and pressure by the pressure regulating valve.

[0056] (Technical Technique 7) The air conditioner according to any one of Technical Techniques 1 to 3, wherein a heat recovery expansion valve is disposed at an inlet of the heat recovery heat exchanger. In this technique 7, the flow rate of the refrigerant flowing through the exhaust heat recovery heat exchanger can be adjusted by the exhaust heat recovery expansion valve.

[0057] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, and the like can be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0058] INDUSTRIAL APPLICABILITY The present disclosure can be suitably used as an air conditioner capable of highly efficient operation by selecting a drive source for a compressor according to an air conditioning load. [Explanation of symbols]

[0059] 1. Air conditioning equipment 10 Outdoor unit 20 Indoor unit 31 Liquid Pipe 32 Gas Pipe 40 Control section 101 First compressor 102 Second compressor 103 Gas Engine 104 Electric motor 106 Four-way valve 107 Outdoor heat exchanger 109 Outdoor expansion valve 110 Accumulator 111 First compressor suction pipe 112 Second compressor suction pipe 115 Waste heat recovery heat exchanger 116 Exhaust heat recovery expansion valve 117 Three-way valve 118 Bypass Pipe 119 First outlet pipe 120 Second outlet pipe 121 Pressure Regulating Valve 122 Check valve 123 Generator 125 Exhaust heat transfer section 201 Indoor heat exchanger 203 Indoor expansion valve

Claims

1. an exhaust heat recovery heat exchanger that heats a refrigerant with exhaust heat from the gas engine; a first outlet pipe that returns the refrigerant that has passed through the exhaust heat recovery heat exchanger to a suction pipe of the first compressor and a suction pipe of the second compressor; a second outlet pipe that returns the refrigerant that has passed through the exhaust heat recovery heat exchanger to a suction pipe of the second compressor; and a control unit that changes a drive source of the compressor according to an air conditioning load request; The control unit drives the first compressor, the second compressor, and the generator in a medium load region during heating operation. Air conditioning equipment.

2. The first compressor has a larger capacity than the second compressor. The air conditioning apparatus according to claim 1.

3. The control unit is During heating operation, in the case of a high load region, the first compressor and the second compressor are driven, and the refrigerant that has passed through the exhaust heat recovery heat exchanger is returned to a suction pipe of the second compressor via the second outlet pipe, In the case of a medium load region, the first compressor, the second compressor, and the generator are driven, and a part of the refrigerant that has passed through the exhaust heat recovery heat exchanger is returned to the suction pipe of the second compressor via the second outlet pipe, and the remainder is returned to the suction pipe of the first compressor via the first outlet pipe. The air conditioning apparatus according to claim 1.

4. The control unit is In the case of a high load region, the gas is returned to the intake pipe of the second compressor at a medium temperature and pressure. In the case of a medium load region, a part of the refrigerant is returned to the suction pipe of the second compressor at a medium temperature and a medium pressure, and the rest is returned to the suction pipe of the first compressor at a low temperature and a low pressure. The air conditioning apparatus according to claim 3.

5. A three-way switching valve is provided at the outlet of the exhaust heat recovery heat exchanger, The first outlet pipe is connected to one outlet of the three-way switching valve, and the second outlet pipe is connected to the other outlet of the three-way switching valve.

5. An air conditioner according to any one of claims 1 to 4.

6. A pressure regulating valve is disposed in the first outlet pipe. The air conditioning apparatus according to claim 5.

7. An exhaust heat recovery expansion valve is disposed at the inlet of the exhaust heat recovery heat exchanger.

5. An air conditioner according to any one of claims 1 to 4.

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