WO2018097124A1

WO2018097124A1 - Air conditioning device

Info

Publication number: WO2018097124A1
Application number: PCT/JP2017/041785
Authority: WO
Inventors: 増田　哲也; 長谷川　寛; 雄章水藤
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2016-11-24
Filing date: 2017-11-21
Publication date: 2018-05-31
Also published as: JPWO2018097124A1; JP6854455B2; GB2571842A; DE112017005948T5; GB2571842B; GB201905450D0

Abstract

Provided is an air conditioning device which has a plurality of compressors connected in parallel, and can be operated at high efficiency regardless of the magnitude of a required load. This air conditioning device is provided with: a first compressor 101 driven by a gas engine 103; a second compressor 102 connected to the first compressor 101 in parallel and having a different capacity from the first compressor 101; a refrigerant tube 115 provided between an indoor heat exchanger 201 and an outdoor heat exchanger 106; a bypass tube 114 connecting the refrigerant tube 115, a suction tube 134 of the first compressor, and a suction tube 135 of the second compressor; an exhaust heat recovery heat exchanger 112 which is provided to the bypass tube 114 and transfers the exhaust heat of the gas engine 103 to the refrigerant; a switching means comprising a first opening/closing means 119 and a second opening/closing means 120, which are disposed downstream from the exhaust heat recovery heat exchanger 112, and are capable of selectively supplying the refrigerant to the first compressor 101 or the second compressor 102; and an inflow prevention means comprising a first check valve 121 provided upstream from a connection part 136 between the suction tube 134 of the first compressor and the bypass tube 114, and a second check valve 122, provided upstream from a connection part 137 between the second compressor 102 and the bypass tube 114.

Description

Air conditioner

The present invention relates to an air conditioner equipped with a compressor driven by a gas engine.

Conventionally, a plurality of compressors having different capacities are mounted on an outdoor unit, a plurality of driving means provided corresponding to each compressor, and the plurality of compressors individually according to the required load size. There has been proposed an air conditioner including a control unit that is driven or combined. (For example, Patent Document 1)

Japanese Patent Laid-Open No. 2003-56931

However, when the refrigerant is heated using the exhaust heat of the gas engine while pumping up heat from the outdoor air in the outdoor heat exchanger during the heating operation as in Patent Document 1, the two compressors inhale. The pressure of the refrigerant will be equal to the pressure of the outdoor heat exchanger with the lower temperature of air and gas engine cooling water as the heat absorption source, and in the heat exchanger using exhaust heat, the temperature of the engine cooling water as the heat absorption source will be adjusted. On the other hand, the temperature difference increases.
Generally, the outdoor air temperature during heating is about 0 to 10 ° C. Therefore, in order to pump heat from the air in the outdoor heat exchanger, the refrigerant evaporating pressure is set to a saturated vapor pressure of about -5 to 5 ° C. There is a need to. On the other hand, since the engine coolant temperature is about 60 to 70 ° C, it is possible to raise the evaporating pressure of the refrigerant sufficiently with respect to the pressure in the outdoor heat exchanger in order to pump up heat in the heat exchanger using exhaust heat. However, in the configuration in which the refrigerant outlet of the outdoor heat exchanger and the outlet of the exhaust heat utilization heat exchanger join at the suction pipe of the compressor, the evaporation pressure of the refrigerant is set to the outdoor heat exchanger, the exhaust heat utilization heat exchanger, and Cannot be set individually. For this reason, the evaporation pressure of the refrigerant in the heat exchanger utilizing exhaust heat needs to be a saturated vapor pressure of about −5 to 5 ° C. In the heat exchanger using exhaust heat, the temperature difference between the heat absorption source and the refrigerant is large, i.e., it does not become the refrigerant evaporation pressure suitable for the temperature of the heat absorption source, and the pressure is reduced wastefully and is evaporated. There is a problem in that an extra compression power for boosting the pressure by the compressor is required, and an efficient operation is not possible.
The present invention solves the above-described conventional problems, and an object of the present invention is to provide an air conditioner that reduces energy consumption during heating, particularly when the required air conditioning load is high.

This specification includes all the contents of Japanese Patent Application No. 2016-228142 filed on Nov. 24, 2016.
In order to solve the above problems, an air conditioner of the present invention includes a first compressor driven by a gas engine, and a second compression connected in parallel to the first compressor and having a different capacity from the first compressor. And a bypass connecting the refrigerant liquid pipe provided between the indoor heat exchanger and the outdoor heat exchanger, the refrigerant liquid pipe, the suction pipe of the first compressor, and the suction pipe of the second compressor A waste heat recovery heat exchanger that is provided in a pipe, the bypass pipe, and moves the exhaust heat of the gas engine to a refrigerant; and provided downstream of the exhaust heat recovery heat exchanger, the first compressor or the first Switching means capable of selectively supplying refrigerant to the two compressors, and a connection portion between the suction pipe and the bypass pipe of the first compressor, or a connection portion between the second compressor and the bypass pipe Provided in either or both of the upstream, the bypass pipe Refrigerant flowing is characterized in that it comprises, an inflow preventing means for preventing the passage.
Thus, during the heating operation, the refrigerant that evaporates in the outdoor heat exchanger and the refrigerant that evaporates in the exhaust heat recovery heat exchanger are sucked into separate compressors without joining. The heat sinks of the air heat exchanger and exhaust heat recovery heat exchanger are air (outside air) and engine exhaust heat cooling water, respectively, and the engine cooling water temperature is higher than the outside air temperature. The refrigerant evaporation pressure in the exhaust heat recovery heat exchange is higher than the refrigerant evaporation pressure.

In the air conditioner of the present invention, it is possible to appropriately set the pressure of the refrigerant that evaporates in the outdoor heat exchanger and the pressure of the refrigerant that evaporates in the exhaust heat recovery heat exchanger according to the temperature of each heat absorption source. .
Since the pressure of the refrigerant evaporating in the exhaust heat recovery heat exchanger can be set higher than the pressure of the refrigerant evaporating in the air heat exchanger, the power of the compressor that sucks the refrigerant evaporated in the exhaust heat recovery heat exchanger is reduced. That is, the energy consumed by the air conditioner during heating can be reduced.

FIG. 1 is a refrigeration cycle diagram of an air conditioner according to an embodiment of the present invention. FIG. 2 shows the optimum operation ratio according to the load size of the gas engine driven compressor and the electric motor driven compressor of the air conditioner in the embodiment. FIG. 3 is a Mollier diagram comparing the conventional refrigeration cycle operating point and the refrigeration cycle operating point in the present embodiment.

An air conditioner according to a first aspect of the present invention includes a first compressor driven by a gas engine, a second compressor connected in parallel with the first compressor and having a different capacity from the first compressor, and indoor heat exchange. A refrigerant liquid pipe provided between the condenser and the outdoor heat exchanger, a bypass pipe connecting the refrigerant liquid pipe, the suction pipe of the first compressor, and the suction pipe of the second compressor, and the bypass pipe Provided in the exhaust heat recovery heat exchanger for transferring the exhaust heat of the gas engine to the refrigerant, and provided downstream of the exhaust heat recovery heat exchanger, and selective to the first compressor or the second compressor Switching means capable of supplying refrigerant, upstream of a connection portion between the suction pipe of the first compressor and the bypass pipe, or upstream of a connection portion of the second compressor and the bypass pipe, or Provided on both sides, the refrigerant flowing from the bypass pipe passes through. Is obtained and a inflow preventing means for preventing the.
Thus, during the heating operation, the refrigerant that evaporates in the outdoor heat exchanger and the refrigerant that evaporates in the exhaust heat recovery heat exchanger are sucked into separate compressors without joining. The heat sinks of the outdoor heat exchanger and the exhaust heat recovery heat exchanger are air (outside air) and engine exhaust heat cooling water, respectively. The engine cooling water temperature is higher than the outside air temperature. The evaporation pressure of the refrigerant in the exhaust heat recovery heat exchanger becomes higher than the evaporation pressure of the refrigerant.
It is possible to appropriately set the pressure of the refrigerant evaporating in the outdoor heat exchanger and the pressure of the refrigerant evaporating in the exhaust heat recovery heat exchanger according to the temperature of each heat absorption source.
Since the pressure of the refrigerant evaporating in the exhaust heat recovery heat exchanger can be set higher than the pressure of the refrigerant evaporating in the outdoor heat exchanger, the power of the compressor that sucks the refrigerant evaporated in the exhaust heat recovery heat exchanger is reduced. That is, the energy consumed by the air conditioner during heating can be reduced.

In the air conditioner according to a second aspect of the invention, the bypass pipe branches into a first branch pipe and a second branch pipe downstream of the exhaust heat recovery heat exchanger, and the first branch pipe is the first compressor. The second branch pipe is connected to the suction pipe of the second compressor, the switching means includes a first opening / closing means provided in the first branch pipe, and the second branch pipe. And a second opening / closing means provided in the.
Also in this invention, it becomes possible to set appropriately the pressure of the refrigerant | coolant which evaporates in an outdoor heat exchanger, and the refrigerant | coolant which evaporates in an exhaust heat recovery heat exchanger according to the temperature of each heat absorption source.
Since the pressure of the refrigerant evaporating in the exhaust heat recovery heat exchanger can be set higher than the pressure of the refrigerant evaporating in the outdoor heat exchanger, the power of the compressor that sucks the refrigerant evaporated in the exhaust heat recovery heat exchanger is reduced. That is, the energy consumed by the air conditioner during heating can be reduced.

In the air conditioner according to a third aspect of the invention, the inflow prevention means is a check valve.
According to the present invention, the refrigerant that evaporates in the outdoor heat exchanger and the refrigerant that evaporates in the exhaust heat recovery heat exchanger pass through the exhaust heat recovery heat exchanger when sucked into separate compressors without being merged. It is only necessary to switch the switching means to supply the refrigerant to the first compressor or the second compressor.
In this case, since the refrigerant that has passed through the outdoor heat exchanger has a lower pressure than the refrigerant that has passed through the exhaust heat recovery heat exchanger, it has passed through the outdoor heat exchanger by providing a check valve as an inflow prevention means. The refrigerant flows to the compressor on the side where the refrigerant that has passed through the exhaust heat recovery heat exchanger does not flow.
Further, the cost can be reduced by a check valve that is cheaper than the on-off valve.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment)
FIG. 1 shows a circuit diagram of an air conditioner 300 according to an embodiment of the present invention.
An air conditioner 300 according to an embodiment of the present invention includes an outdoor unit 100 and an indoor unit 200.
The outdoor unit 100 includes a gas engine 103 that uses gas as a driving source, a first compressor 101 that compresses refrigerant by obtaining driving force from the gas engine 103, a second compressor 102 that uses an electric motor as a driving source, Is provided. The first compressor 101 having a larger capacity than the second compressor 102 is selected.
The second compressor 102 may be a compressor that compresses the refrigerant by obtaining a driving force from a gas engine.

An oil separator 104 is provided in the merged discharge pipe 123 where the discharge pipe of the first compressor 101 and the discharge pipe of the second compressor 102 merge. The oil separator 104 separates oil contained in the refrigerant gas discharged from the first compressor 101 and the second compressor 102.
The oil separated in the oil separator 104 is returned to the suction pipe 134 of the first compressor and the suction pipe 135 of the second compressor through an oil return pipe (not shown).
A four-way valve 105 is provided downstream of the oil separator 104. The four-way valve 105 is for switching the refrigeration cycle between cooling and heating. In FIG. 1, heating operation is performed when the refrigerant flows through the solid line, and cooling operation is performed when the refrigerant flows through the dotted line.

The junction discharge pipe 123 is connected to one end of the indoor heat exchanger 201 in the indoor unit 200. The indoor unit 200 includes an indoor heat exchanger 201, an indoor blower fan 202, and an indoor decompression device 203.
The refrigerant pipe 130 connected to the other end of the indoor heat exchanger 201 is connected to one end of the outdoor heat exchanger 106 in the outdoor unit 100 via the indoor pressure reducing device 203 and the outdoor pressure reducing device 108.
Of the refrigerant pipes 130, a pipe between the indoor pressure reducing device 203 and the outdoor pressure reducing device 108 is defined as a refrigerant liquid pipe 115.
A radiator 111 is provided on the leeward side of the outdoor heat exchanger 106, and engine cooling water is radiated by the outdoor fan 107.

The suction pipe 133 connected to the other end of the outdoor heat exchanger 106 branches to the suction pipe 134 of the first compressor and the suction pipe 135 of the second compressor via the four-way valve 105. The suction pipe 134 of the first compressor is connected to the suction port of the first compressor 101 via the accumulator 109. The suction pipe 135 of the second compressor is connected to the suction port of the second compressor 102 via the accumulator 110.

The air conditioner 300 includes a bypass pipe 114 that connects the refrigerant liquid pipe 115, the suction pipe 134 of the first compressor, and the suction pipe 135 of the second compressor.
The bypass pipe 114 is provided with a pressure reducing device 113. A waste heat recovery heat exchanger 112 that moves the exhaust heat of the gas engine 103 to the refrigerant is provided downstream of the decompression device 113. Since the decompression device 113 and the exhaust heat recovery heat exchanger 112 are provided, the air conditioner 300 can absorb heat from the engine cooling water during heating.

The bypass pipe 114 branches into a first branch pipe 117 and a second branch pipe 118 at a bypass branch section 116 provided downstream of the exhaust heat recovery heat exchanger 112. The first branch pipe 117 is connected to the suction pipe 134 of the first compressor. The second branch pipe 118 is connected to the suction pipe 135 of the second compressor. The first branch pipe 117 includes first opening / closing means 119. The second branch pipe 118 includes a second opening / closing means 120.
For the first opening / closing means 119, for example, an opening / closing valve can be used.
As the second opening / closing means 120, for example, an opening / closing valve can be used.

The first opening / closing means 119 and the second opening / closing means 120 constitute a switching means.
By selectively opening and closing the first opening / closing means 119 and the second opening / closing means 120, the refrigerant that has passed through the exhaust heat recovery heat exchanger 112 is selectively supplied to the first compressor 101 or the second compressor 102. Can do.

As the switching means, for example, a switching valve such as a three-way valve may be used for the bypass branch portion 116.
Further, for example, the switching means may be only one of the first opening / closing means 119 and the second opening / closing means 120.

A first check valve 121 is provided at a position upstream of the connection 136 between the suction pipe 134 and the first branch pipe 117 of the first compressor. A second check valve 122 is provided at a position upstream of the connection portion 137 between the suction pipe 135 and the second branch pipe 118 of the second compressor.

The first check valve 121 and the second check valve 122 constitute inflow prevention means.
By the first check valve 121 and the second check valve 122, exhaust heat recovery having a higher pressure than the refrigerant supplied from the outdoor heat exchanger 106 is performed on the refrigerant side having a lower pressure supplied from the outdoor heat exchanger 106. It is possible to prevent the refrigerant supplied from the heat exchanger 112 from flowing backward.

The inflow prevention means may be any means that can prevent the refrigerant flowing from the first branch pipe 117 to the suction pipe 134 of the first compressor from flowing back to the suction pipe 133. Further, the inflow preventing means may be any means that can prevent the refrigerant flowing from the second branch pipe 118 to the suction pipe 135 of the second compressor from flowing back to the suction pipe 133.
As the inflow prevention means, for example, a first on-off valve can be used instead of the first check valve 121, and a second on-off valve can be used instead of the second check valve 122.
Further, for example, a switching valve such as a three-way valve is used as a inflow prevention means at a location where three pipes of the suction pipe 133, the suction pipe 134 of the first compressor, and the suction pipe 135 of the second compressor are connected. May be.

Next, the operations of the outdoor unit 100 and the indoor unit 200 will be described using FIG. 1 for the cooling operation, the heating operation, and the respective operation states, divided into required load sizes.

(Cooling operation at low load)
At the time of low load of the cooling operation, only the second compressor 102 using the electric motor as a drive source is driven. The first opening / closing means 119 and the second opening / closing means 120 are closed. The four-way valve 105 is set so that the refrigerant flows along the dotted line.

The high-temperature and high-pressure refrigerant compressed by the second compressor 102 flows into the oil separator 104. The high-purity gas refrigerant from which oil has been separated in the oil separator 104 passes through the four-way valve 105 and enters the outdoor heat exchanger 106. The gas refrigerant exchanges heat with the outside air in the outdoor heat exchanger 106, dissipates heat, condenses, becomes high-pressure liquid refrigerant, passes through the outdoor decompression device 108, and is supplied to the indoor unit 200.
The high-pressure liquid refrigerant that has entered the indoor unit 200 is decompressed by the indoor decompression device 203, enters a gas-liquid two-phase state, and flows into the indoor heat exchanger 201. The refrigerant in the gas-liquid two-phase state evaporates after exchanging heat with the air in the space to be air-conditioned in the indoor heat exchanger 201 and then flows out from the indoor unit 200 as a gas refrigerant.

The gas refrigerant that has flowed out of the indoor unit 200 returns to the outdoor unit 100 again. The gas refrigerant flowing into the outdoor unit 100 returns to the second compressor 102 through the four-way valve 105 and the accumulator 110 and repeats the above process.

(At load during cooling operation)
When the cooling operation is at a medium load, the first compressor 101 using the gas engine 103 as a drive source is driven. The first opening / closing means 119 and the second opening / closing means 120 are closed. The four-way valve 105 is set so that the refrigerant flows along the dotted line.

The high-temperature and high-pressure refrigerant compressed by the first compressor 101 flows into the oil separator 104. The high-purity gas refrigerant from which oil has been separated in the oil separator 104 passes through the four-way valve 105 and enters the outdoor heat exchanger 106. The gas refrigerant exchanges heat with the outside air in the outdoor heat exchanger 106, dissipates heat, condenses, becomes high-pressure liquid refrigerant, passes through the outdoor decompression device 108, and is supplied to the indoor unit 200.
The high-pressure liquid refrigerant that has entered the indoor unit 200 is decompressed by the indoor decompression device 203, enters a gas-liquid two-phase state, and flows into the indoor heat exchanger 201. The refrigerant in the gas-liquid two-phase state evaporates after exchanging heat with the air in the space to be air-conditioned in the indoor heat exchanger 201 and then flows out from the indoor unit 200 as a gas refrigerant.

The gas refrigerant that has flowed out of the indoor unit 200 returns to the outdoor unit 100 again. The gas refrigerant flowing into the outdoor unit 100 returns to the first compressor 101 through the four-way valve 105 and the accumulator 109 and repeats the above process.
The exhaust heat generated in the gas engine 103 is transferred to the radiator 111 by engine cooling water and a pump (not shown), exchanges heat with the outside air, and returns to the gas engine 103 again.

(Cooling operation at high load)
At the time of high load in the cooling operation, both the first compressor 101 using the gas engine 103 as a drive source and the second compressor 102 using the electric motor as a drive source are driven. The first opening / closing means 119 and the second opening / closing means 120 are closed. The four-way valve 105 is set so that the refrigerant flows along the dotted line.

The high-temperature and high-pressure refrigerant compressed by the first compressor 101 and the second compressor 102 flows into the oil separator 104. The refrigerant flowing into the oil separator 104 becomes a high-purity gas refrigerant from which oil has been separated, passes through the four-way valve 105, and enters the outdoor heat exchanger 106. The gas refrigerant exchanges heat with the outside air in the outdoor heat exchanger 106, dissipates heat, condenses, becomes high-pressure liquid refrigerant, passes through the outdoor decompression device 108, and is supplied to the indoor unit 200.
The high-pressure liquid refrigerant that has entered the indoor unit 200 is decompressed by the indoor decompression device 203, enters a gas-liquid two-phase state, and flows into the indoor heat exchanger 201. The refrigerant in the gas-liquid two-phase state evaporates after exchanging heat with the air in the space to be air-conditioned in the indoor heat exchanger 201 and then flows out from the indoor unit 200 as a gas refrigerant.

The gas refrigerant that has flowed out of the indoor unit 200 returns to the outdoor unit 100 again. The gas refrigerant flowing into the outdoor unit 100 flows into the suction pipe 134 of the first compressor or the suction pipe 135 of the second compressor through the four-way valve 105. The gas refrigerant flowing into the suction pipe 134 of the first compressor returns to the first compressor 101 through the accumulator 109 and repeats the above process. The gas refrigerant that has flowed into the suction pipe 135 of the second compressor returns to the second compressor 102 through the accumulator 110 and repeats the above process.
The exhaust heat generated in the gas engine 103 is transferred to the radiator 111 by engine cooling water and a pump (not shown), exchanges heat with the outside air, and returns to the gas engine 103 again.

(When heating operation is under low load)
At the time of low load of the heating operation, only the second compressor 102 using the electric motor as a drive source is driven. The first opening / closing means 119 and the second opening / closing means 120 are closed. The four-way valve 105 is set so that the refrigerant flows through the solid line.

The high-temperature and high-pressure refrigerant compressed by the second compressor 102 flows into the oil separator 104. The high-purity gas refrigerant from which oil has been separated by the oil separator 104 passes through the four-way valve 105 and is supplied to the indoor unit 200.
The high-temperature and high-pressure gas refrigerant that has entered the indoor unit 200 flows into the indoor heat exchanger 201, exchanges heat with the air in the space to be air-conditioned, dissipates heat, condenses, and becomes liquid refrigerant to form the indoor decompression device. It flows out of the indoor unit 200 through 203.

The liquid refrigerant that has flowed out of the indoor unit 200 returns to the outdoor unit 100 again. The liquid refrigerant that has flowed into the outdoor unit 100 is depressurized by the outdoor pressure reducing device 108, enters a gas-liquid two-phase state, and flows into the outdoor heat exchanger 106. The refrigerant in the gas-liquid two-phase state exchanges heat with the outside air in the outdoor heat exchanger 106, absorbs heat, evaporates, becomes a gas refrigerant, returns to the second compressor 102 through the four-way valve 105 and the accumulator 110, and Repeat the process.

(At the time of load during heating operation)
When the heating operation is at a medium load, the first compressor 101 using the gas engine 103 as a drive source is driven. The first opening / closing means 119 and the second opening / closing means 120 are closed. The four-way valve 105 is set so that the refrigerant flows through the solid line.

The high-temperature and high-pressure refrigerant compressed by the first compressor 101 flows into the oil separator 104. The high-purity gas refrigerant from which oil has been separated by the oil separator 104 passes through the four-way valve 105 and is supplied to the indoor unit 200.
The high-temperature and high-pressure gas refrigerant that has entered the indoor unit 200 flows into the indoor heat exchanger 201, exchanges heat with the air in the space to be air-conditioned, dissipates heat, condenses, and becomes liquid refrigerant to form the indoor decompression device. It flows out of the indoor unit 200 through 203.

The liquid refrigerant that has flowed out of the indoor unit 200 returns to the outdoor unit 100 again. The liquid refrigerant that has flowed into the outdoor unit 100 is depressurized by the outdoor pressure reducing device 108, enters a gas-liquid two-phase state, and flows into the outdoor heat exchanger 106. The gas-liquid two-phase refrigerant absorbs heat by exchanging heat with the outside air and then evaporates to become a gas refrigerant. Thereafter, the process returns to the first compressor 101 through the four-way valve 105 and the accumulator 109, and the above process is repeated.

(Heating operation at extremely low temperature)
At the extremely low temperature of the heating operation, the first compressor 101 using the gas engine 103 as a drive source and the second compressor 102 using the electric motor as a drive source are driven. The first opening / closing means 119 and the second opening / closing means 120 are opened, and the outdoor decompression device 108 is closed. The four-way valve 105 is set so that the refrigerant flows through the solid line.

The high-temperature and high-pressure refrigerant compressed by the first compressor 101 and the second compressor 102 flows into the oil separator 104. The high-purity gas refrigerant from which oil has been separated by the oil separator 104 passes through the four-way valve 105 and is supplied to the indoor unit 200.
The high-temperature and high-pressure gas refrigerant that has entered the indoor unit 200 flows into the indoor heat exchanger 201, exchanges heat with the air in the space to be air-conditioned, dissipates heat, condenses, and becomes liquid refrigerant to form the indoor decompression device. It flows out of the indoor unit 200 through 203.

The liquid refrigerant flowing out from the indoor unit 200 returns to the outdoor unit 100 again. The liquid refrigerant that has flowed into the outdoor unit 100 flows through the bypass pipe 114, is decompressed by the decompression device 113, enters a gas-liquid two-phase state, and flows into the exhaust heat recovery heat exchanger 112. The refrigerant in the gas-liquid two-phase state evaporates after exchanging heat with the engine cooling water, and becomes a medium-temperature / medium-pressure gas refrigerant. Thereafter, the medium-temperature and medium-pressure gas refrigerant is branched by the bypass branch 116, and a part of the refrigerant flows through the first branch pipe 117, passes through the first opening / closing means 119 and the accumulator 109, and enters the first compressor 101. Return and repeat the above process. The remaining refrigerant flows through the second branch pipe 118, returns to the second compressor 102 through the second opening / closing means 120 and the accumulator 110, and repeats the above process.
At this time, since the outdoor pressure reducing device 108 is closed, the refrigerant does not flow into the outdoor heat exchanger 106. This is to prevent the outdoor heat exchanger 106 from being frosted because the outside air temperature is low.

(Heating operation at high load)
At the time of high load during heating operation, the first compressor 101 using the gas engine 103 as a drive source and the second compressor 102 using the electric motor as a drive source are driven. The first opening / closing means 119 is closed and the second opening / closing means 120 is opened. The four-way valve 105 is set so that the refrigerant flows through the solid line.

The high-temperature and high-pressure refrigerant compressed by the first compressor 101 and the second compressor 102 flows into the oil separator 104. The refrigerant that has flowed into the oil separator 104 becomes a high-purity gas refrigerant from which oil has been separated, passes through the four-way valve 105, and is supplied to the indoor unit 200.
The high-temperature and high-pressure gas refrigerant that has entered the indoor unit 200 flows into the indoor heat exchanger 201, exchanges heat with the air in the space to be air-conditioned, dissipates heat, condenses, and becomes liquid refrigerant to form the indoor decompression device. It flows out of the indoor unit 200 through 203.

The liquid refrigerant that has flowed out of the indoor unit 200 returns to the outdoor unit 100 again. A part of the liquid refrigerant flowing into the outdoor unit 100 flows into the bypass pipe 114. The remaining liquid refrigerant that has not flowed into the bypass pipe 114 is depressurized by the outdoor pressure reducing device 108, enters a gas-liquid two-phase state, and flows into the outdoor heat exchanger 106. The gas-liquid two-phase refrigerant absorbs heat by exchanging heat with the outside air and then evaporates to become a low-temperature and low-pressure gas refrigerant. Thereafter, it returns to the first compressor 101 through the four-way valve 105 and the accumulator 109.

The liquid refrigerant that has flowed into the bypass pipe 114 is depressurized by the decompression device 113, enters a gas-liquid two-phase state, and flows into the exhaust heat recovery heat exchanger 112. The gas-liquid two-phase refrigerant that has flowed into the exhaust heat recovery heat exchanger 112 absorbs heat from engine cooling water (not shown) and evaporates to become a medium-temperature / medium-pressure gas refrigerant. The medium-temperature and medium-pressure gas refrigerant passes through the bypass branch 116 and the second branch pipe 118 and returns to the second compressor 102. Here, since the first opening / closing means 119 is closed, the medium-temperature medium-pressure gas refrigerant flows into the suction pipe 135 of the second compressor via the second branch pipe 118, and the suction of the second compressor Since the pipe 135 is provided with the second check valve 122, the medium-temperature and intermediate-pressure gas refrigerant is not sucked into the first compressor 101.

Therefore, the low-temperature and low-pressure gas refrigerant evaporated in the outdoor heat exchanger 106 returns to the first compressor 101 and is compressed into the high-temperature and high-pressure gas refrigerant. The medium-temperature and medium-pressure gas refrigerant evaporated in the exhaust heat recovery heat exchanger 112 is returned to the second compressor 102, compressed into a high-temperature and high-pressure gas refrigerant, and the above process is repeated.

Heating operation at extremely low temperatures and high heating loads are divided according to the outside air temperature. For example, when the outdoor air temperature is lower than 0 ° C., the outdoor heat exchanger 106 is more likely to be frosted. Therefore, the operation pattern at the extremely low heating temperature is selected, and the outdoor heat exchanger 106 performs heat absorption. The frost formation is avoided by absorbing heat only from the exhaust heat recovery heat exchanger 112. When the outside air temperature is 0 ° C. or higher, the operation pattern at the time of heating and high load is selected, and the heat absorption in the outdoor heat exchanger 106 and the heat absorption in the exhaust heat recovery heat exchanger 112 are used in combination.

In the above air conditioner 300, as shown in FIG. 2, if the air conditioning load is small, only the second compressor 102 driven by the electric motor is driven, and if the air conditioning load is medium, it is driven by the gas engine. When the air conditioning load is high, the first compressor 101 driven by the gas engine is driven at the maximum output, and the shortage is driven by the second compressor 102 driven by the electric motor. It has been found from the results of the trial calculation by the inventors and the actual machine evaluation results that the highest energy efficiency can be obtained by making up.
The same explanation is given for the conventional air conditioner. However, in the conventional air conditioner, when the air conditioning load is high in the heating operation, the gas engine pumps heat from the outdoor air in the outdoor heat exchanger. The refrigerant is heated using the exhaust heat. The pressure of the refrigerant sucked by the two compressors is equal to the pressure of the outdoor heat exchanger where the temperature of the heat absorption source is lower than the air that is the heat absorption source and the gas engine cooling water. The temperature difference with the refrigerant increases with respect to the engine coolant temperature that is the heat absorption source.

Generally, the outdoor air temperature during heating is about 0 to 10 ° C. Therefore, in order to pump heat from the air in the outdoor heat exchanger, the refrigerant evaporating pressure is set to a saturated vapor pressure of about -5 to 5 ° C. There is a need to. On the other hand, since the engine coolant temperature is about 60 to 70 ° C, it is possible to raise the evaporating pressure of the refrigerant sufficiently with respect to the pressure in the outdoor heat exchanger in order to pump up heat in the heat exchanger using exhaust heat. It is. However, when the refrigerant outlet of the outdoor heat exchanger and the outlet of the exhaust heat utilization heat exchanger are combined in the suction pipe of the compressor, the refrigerant evaporating pressure is exchanged with the outdoor heat exchanger and the exhaust heat utilization heat exchange. Cannot be set individually with the instrument. Therefore, when the refrigerant outlet of the outdoor heat exchanger and the outlet of the exhaust heat utilization heat exchanger are combined in the suction pipe of the compressor, the evaporation pressure of the refrigerant of the exhaust heat utilization heat exchanger is also −5. It is necessary to have a saturated vapor pressure of about 5 ° C. In the heat exchanger using exhaust heat, the temperature difference between the heat absorption source and the refrigerant is large, i.e., it does not become the refrigerant evaporation pressure suitable for the temperature of the heat absorption source, and the pressure is reduced wastefully and is evaporated. There is a problem in that an extra compression power for boosting the pressure again by the compressor is required, and an efficient operation cannot be performed.

In the air conditioning apparatus 300 according to the present embodiment, when the air conditioning load is high during heating operation, the first compressor 101 driven by the gas engine compresses the low-temperature and low-pressure gas refrigerant to high temperature and high pressure, and is driven by the electric motor. The second compressor 102 is configured to compress the medium-temperature and medium-pressure gas refrigerant to a high temperature and a high pressure. Therefore, as shown in the Mollier diagram of the present embodiment in FIG. 3, the suction pressure of the second compressor 102 driven by the electric motor is higher than the suction pressure in the conventional example, and is driven by the electric motor. Since the compression ratio (high pressure / low pressure) of the second compressor 102 becomes low, the energy consumed by the second compressor 102 driven by the electric motor can be reduced as compared with the conventional example.

In this embodiment, at the time of heating and high load, the low-temperature and low-pressure gas refrigerant is sucked into the first compressor 101 driven by the gas engine, and the medium-temperature and medium-pressure gas refrigerant is driven by the electric motor. However, the low temperature and low pressure gas refrigerant may be sucked into the second compressor 102 driven by the electric motor, and the medium temperature and medium pressure gas refrigerant may be sucked into the first compressor 101 driven by the gas engine. . Further, both the first and second compressors may be driven by a gas engine.

In contrast to the present embodiment, the refrigerant liquid pipe 115 has two bypass pipes, two exhaust heat recovery heat exchangers are provided in parallel, one of them is a suction pipe of a compressor driven by a gas engine, and the other is electric As in this embodiment, the first compressor is connected to the suction pipe of the compressor driven by the motor, and an opening / closing valve is provided upstream from the connection portion of the bypass pipe in the suction pipe of each compressor. It is possible to individually set the refrigerant suction pressure and the refrigerant suction pressure in the second compressor.
However, in the above example, since the exhaust heat recovery heat exchangers are provided in parallel, it is necessary to provide two systems of engine cooling water circuits as heat absorption sources, and the cooling water circuit becomes complicated. Furthermore, when both exhaust heat recovery heat exchangers are used at the same time (when heating is extremely low in this embodiment), if one of the exhaust heat recovery heat exchangers has an excess or deficiency in the amount of cooling water, it will be affected. In addition, the amount of cooling water in the other exhaust heat recovery heat exchanger also becomes excessive or insufficient.
For example, if excessive cooling water is supplied to one exhaust heat recovery heat exchanger, the amount of cooling water in the other exhaust heat recovery heat exchanger will be insufficient, and the exhaust heat recovery heat exchanger with insufficient cooling water will Evaporation cannot be performed sufficiently, resulting in liquid back, which may lead to compressor failure. Also, in an exhaust heat recovery heat exchanger supplied with an excessive amount of cooling water, the refrigerant is heated excessively and the discharge temperature of the refrigerant becomes high, so that the oil that lubricates the compressor deteriorates, When the motor is a drive source, there is a problem in reliability such as damage to the motor.
Therefore, when the suction pressure of the refrigerant in the first compressor 101 and the suction pressure in the second compressor 102 are individually set, the exhaust heat recovery heat exchanger 112 is set as one as in this embodiment, It is desirable that the refrigerant flow path that has passed through the exhaust heat recovery heat exchanger 112 is branched and connected to each of the first compressor 101 and the second compressor 102.

As described above, according to the present embodiment, the first compressor 101 driven by the gas engine 103 and the second compressor connected in parallel with the first compressor 101 and having different capacities from the first compressor 101. , The refrigerant liquid pipe 115 provided between the indoor heat exchanger 201 and the outdoor heat exchanger 106, the refrigerant liquid pipe 115, the suction pipe 134 of the first compressor, and the suction pipe 135 of the second compressor Are provided in the bypass pipe 114, the exhaust heat recovery heat exchanger 112 that moves the exhaust heat of the gas engine 103 to the refrigerant, and the downstream of the exhaust heat recovery heat exchanger 112, Connection between the switching means including the first opening / closing means 119 and the second opening / closing means 120 capable of selectively supplying the refrigerant to the compressor 101 or the second compressor 102, and the suction pipe 134 and the bypass pipe 114 of the first compressor Part 1 6 and a first check valve 121 provided upstream of 6, and an inflow prevention means including a second check valve 122 provided upstream of the connecting portion 137 between the second compressor 102 and the bypass pipe 114. .
Thus, when the air conditioning load is high during heating operation, the first compressor 101 driven by the gas engine 103 compresses the low-temperature and low-pressure gas refrigerant to a high temperature and high pressure, and the second compressor 102 driven by the electric motor is in the middle temperature. In order to compress the high-pressure gas refrigerant to high temperature and high pressure, the pressure of the refrigerant evaporating in the outdoor heat exchanger 106 and the pressure of the refrigerant evaporating in the exhaust heat recovery heat exchanger 112 are appropriately set according to the temperature of the respective heat absorption sources. It becomes possible to do.
That is, since the pressure of the refrigerant evaporating in the exhaust heat recovery heat exchanger 112 can be set higher than the pressure of the refrigerant evaporating in the outdoor heat exchanger, the compressor that sucks in the refrigerant evaporated in the exhaust heat recovery heat exchanger 112 The energy consumed by the air conditioner 300 during heating can be reduced.

Further, according to the present embodiment, the bypass pipe 114 branches into the first branch pipe 117 and the second branch pipe 118 downstream of the exhaust heat recovery heat exchanger 112, and the first branch pipe 117 is compressed by the first compression pipe. The second branch pipe 118 is connected to the suction pipe 135 of the second compressor, and the switching means includes a first opening / closing means 119 provided in the first branch pipe 117 and a second branch. And a second opening / closing means 120 provided in the pipe 118.
Also in the present invention, the pressure of the refrigerant evaporating in the outdoor heat exchanger 106 and the pressure of the refrigerant evaporating in the exhaust heat recovery heat exchanger 112 can be appropriately set according to the temperature of each heat absorption source.
Since the pressure of the refrigerant evaporating in the exhaust heat recovery heat exchanger 112 can be set higher than the pressure of the refrigerant evaporating in the outdoor heat exchanger 106, the compressor of the compressor that sucks the refrigerant evaporated in the exhaust heat recovery heat exchanger 112 is set. Power can be reduced, that is, the energy consumed by the air conditioner 300 during heating can be reduced.

Moreover, according to this Embodiment, the 1st check valve 121 and the 2nd check valve 122 were used as an inflow prevention means.
Therefore, when the refrigerant evaporating in the outdoor heat exchanger 106 and the refrigerant evaporating in the exhaust heat recovery heat exchanger 112 are sucked into separate compressors without being merged, the refrigerant that has passed through the exhaust heat recovery heat exchanger 112 The first opening / closing means 119 and the second opening / closing means 120 as switching means need only be switched in order to supply the first compressor 101 or the second compressor 102 with
In this case, since the refrigerant that has passed through the outdoor heat exchanger 106 has a lower pressure than the refrigerant that has passed through the exhaust heat recovery heat exchanger 112, the first check valve 121 and the second check valve 122 are provided. The refrigerant that has passed through the outdoor heat exchanger 106 flows to the compressor on the side where the refrigerant that has passed through the exhaust heat recovery heat exchanger 112 does not flow.
Further, by using the first check valve 121 and the second check valve 122, the cost can be reduced as compared with the case where the on-off valve is used.

As mentioned above, although this invention was demonstrated based on this Embodiment, this invention is not limited to these embodiment. Since the embodiments of the present invention are merely illustrated, modifications and applications can be arbitrarily made without departing from the spirit of the present invention.

The air conditioner according to the present invention is suitably used as an air conditioner capable of performing high-efficiency operation regardless of the air conditioning load by selecting a compressor drive source according to the air conditioning load. Can do.

DESCRIPTION OF SYMBOLS 100 Outdoor unit 101 1st compressor 102 2nd compressor 103 Gas engine 108 Outdoor decompression device 112 Waste heat recovery heat exchanger 113 Decompression device 115 Refrigerant liquid pipe 116 Bypass branch part 117 First branch pipe 118 Second branch pipe 119 1st One open / close valve (switching means)
120 Second on-off valve (switching means)
121 First check valve (inflow prevention means)
122 Second check valve (inflow prevention means)
134 Suction Pipe of First Compressor 135 Suction Pipe of Second Compressor 200 Indoor Unit 203 Indoor Pressure Reduction Device 300 Air Conditioner

Claims

A first compressor driven by a gas engine;
A second compressor connected in parallel with the first compressor and having a different capacity from the first compressor;
A refrigerant liquid pipe provided between the indoor heat exchanger and the outdoor heat exchanger;
A bypass pipe connecting the refrigerant liquid pipe, the suction pipe of the first compressor, and the suction pipe of the second compressor;
An exhaust heat recovery heat exchanger provided in the bypass pipe for moving the exhaust heat of the gas engine to a refrigerant;
Switching means provided downstream of the exhaust heat recovery heat exchanger and capable of selectively supplying a refrigerant to the first compressor or the second compressor;
Provided in either or both of the upstream side of the connection portion between the suction pipe and the bypass pipe of the first compressor or the upstream side of the connection portion of the second compressor and the bypass pipe, and flows from the bypass pipe And an inflow prevention means for preventing the refrigerant to pass.
The bypass pipe branches into a first branch pipe and a second branch pipe downstream of the exhaust heat recovery heat exchanger,
The first branch pipe is connected to a suction pipe of the first compressor;
The second branch pipe is connected to a suction pipe of the second compressor;
2. The air conditioner according to claim 1, wherein the switching unit includes a first opening / closing unit provided in the first branch pipe and a second opening / closing unit provided in the second branch pipe.
3. The air conditioner according to claim 1 or 2, wherein the inflow prevention means is a check valve.