JP5641004B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus using a refrigerant such as a fluid in a supercritical state, and particularly to a configuration of a refrigeration cycle apparatus having good performance such as efficiency improvement.

  The following is an example of an air conditioning system that separates latent heat and sensible heat of air, which is a conventional air conditioning load for performance improvement, and this air conditioning system can reduce drain piping and introduce outside air. An air conditioning system with a high degree of freedom of arrangement of the sensible heat cooling unit is known even when it is performed. That is, it is an air conditioning system that cools a predetermined space, and includes a sensible heat cooling unit and an outside air supply unit. The sensible heat cooling unit controls the cooling heat source so as to be equal to or higher than the dew point temperature of the air in the space to sensible heat cool the space. The outside air supply unit is a unit that supplies outside air to the space, and reduces the absolute humidity of the outside air supplied to the space to reduce the latent heat load of the outside air.

  Specifically, the conventional air conditioning system includes an indoor unit, an outdoor air supply unit, and an outdoor unit. The indoor unit includes an intake air temperature / relative humidity detector, and the absolute humidity of the indoor space is determined based on the detection result. Is calculated. The outside air supply unit includes a blown air temperature / relative humidity detector and a controller, and calculates the absolute humidity of the outside air supplied to the indoor space based on the detection result. The target evaporation temperature calculation unit calculates the target evaporation temperature of the refrigerant for performing an appropriate latent heat treatment based on the absolute humidity calculated by each control unit (see, for example, Patent Document 1). .

  Furthermore, a plurality of heat exchangers are provided in the load-side unit of the two-stage compression refrigeration cycle, one of which is a sensible heat treatment heat exchanger having one end connected to the suction side of the high-stage compressor. One is a heat exchanger for latent heat treatment, one end of which is connected to the suction side of the low-stage compressor, and an apparatus capable of controlling the indoor temperature and humidity with a simple structure with this configuration is known (for example, Patent Document 2). reference).

Japanese Patent Laying-Open No. 2005-49059 (Claim 1, FIG. 2, etc.) Japanese Patent Laying-Open No. 2005-98607 (column 0009, FIG. 1)

  In the conventional example, in the refrigeration cycle apparatus that separates the latent heat load and the sensible heat load in the air-conditioning target space, and adopts a single-stage compression method, the refrigerant is removed from the low evaporation temperature of the outside air supply unit that processes the latent heat load. There was a need to compress. Therefore, there has been a problem that the efficiency is lowered as compared with a two-stage compression refrigeration cycle using a compressor corresponding to the evaporation temperature of each of the sensible heat cooling unit and the outside air supply unit. Moreover, when using the refrigerant | coolant which will be in a supercritical state, such as a carbon dioxide, while the expansion loss became large, the freezing effect became small and there existed a subject that efficiency fell.

  The present invention has been made in order to solve the conventional problems as described above, and an object thereof is to obtain a refrigeration cycle apparatus capable of increasing the efficiency when a supercritical fluid is used. It is a further object of the present invention to obtain an efficient apparatus for processing a thermal load by separating it into latent heat and sensible heat. Further, the present invention improves efficiency by cooling the condensed refrigerant from the outside.

A refrigeration cycle apparatus according to the present invention includes a first compressor that discharges a refrigerant that is in a supercritical state, first flow path switching means that can switch between a cooling operation and a heating operation, and a heat source side heat exchanger. A load device having a heat source device, a first pressure reducing means, and a first load side heat exchanger, and a first pipe for supplying a refrigerant from the heat source device to the load device during cooling operation, An expander driven by a refrigerant, a gas-liquid separator provided in the first pipe for gas-liquid separation, and refrigerant from the heat source side heat exchanger so as to bypass the expander to the gas-liquid separator And a second expansion valve provided on the downstream side of the liquid refrigerant of the gas-liquid separator, and the pressure is reduced by the second decompression means and the second load side heat exchanger. The second compressor driven by the expander increases the pressure Because, the refrigerant becomes a high pressure by the second compressor is drawn from the load device to the first compressor via the second pipe for supplying refrigerant during the cooling operation to the heat source unit, before Symbol the first expansion valve, at least one of the previous SL expander and the second compressor power by adjusting the degree of opening so as to match the said second expansion valve and the first pressure reducing means, wherein When the power does not match only by adjusting the opening of the first expansion valve, the opening is adjusted so as to match the power .

In the refrigeration cycle apparatus of the present invention, the power of the second compressor is not required, and a highly efficient refrigeration cycle apparatus can be obtained.

It is a figure which shows the refrigerant circuit structure using the internal heat exchanger which concerns on Embodiment 1 of this invention. It is a figure which shows the operation | movement of the air_conditionaing | cooling operation on the Ph diagram which concerns on Embodiment 1 of this invention. It is a figure which shows the operation | movement of the heating operation on the Ph diagram which concerns on Embodiment 1 of this invention. It is a figure which shows the other example using the internal heat exchanger which concerns on Embodiment 1 of this invention. It is a figure which shows the watering method to the heat exchanger which concerns on Embodiment 1 of this invention. It is a figure which shows the heat exchanger suitable for the watering which concerns on Embodiment 1 of this invention. It is a figure which shows the other heat exchanger suitable for the watering which concerns on Embodiment 1 of this invention. It is a figure which shows the refrigerant circuit structure using the ejector which concerns on Embodiment 1 of this invention. It is a figure which shows the internal structure of the ejector which concerns on Embodiment 1 of this invention, and the pressure change of a flow direction. It is a figure which shows the operation | movement of the air_conditionaing | cooling operation on the Ph diagram which concerns on Embodiment 1 of this invention. It is the figure which made the heat exchanger 12 and the heat exchanger 18 which concern on Embodiment 1 of this invention integrated. It is the figure which made the indoor unit 200 and the external air processing unit 300 which concern on Embodiment 1 of this invention integrated. It is a figure which shows the form of the heat exchanger which processes the sensible heat which concerns on Embodiment 1 of this invention. It is a figure which shows the other example of the refrigerant circuit structure using the ejector which concerns on Embodiment 1 of this invention. It is a figure which shows the refrigerant circuit structure using the expander which concerns on Embodiment 1 of this invention. It is a figure which shows the operation | movement of the air_conditionaing | cooling operation on the Ph diagram which concerns on Embodiment 1 of this invention. It is a figure which shows the humidification method at the time of heating operation.

Embodiment 1 FIG.
Hereinafter, the refrigeration cycle apparatus according to Embodiment 1 of the present invention will be described. FIG. 1 is a schematic diagram showing a refrigeration cycle apparatus according to Embodiment 1 of the present invention. In the figure, the refrigeration cycle apparatus according to the present embodiment includes a heat source unit 100 including a heat source side heat exchanger 3, indoor units 200a and 200b including first load side heat exchangers 5a and 5b, and a second load side. The outside air processing unit 300 incorporating the heat exchanger 12, the liquid pipe 52 and the gas pipe 51 that connect the heat source unit 100 to the outside air processing unit 300 and the like are configured. For example, carbon dioxide that is in a supercritical state at a critical temperature (about 31 ° C.) or higher is sealed inside the cycle as a refrigerant.

  In the heat source unit 100 arranged outdoors, a first compressor 1 for compressing the refrigerant gas, and a first refrigerant flow switching means for switching the direction in which the refrigerant flows according to the cooling operation and the heating operation of the indoor unit. The four-way valve 2, the outdoor heat exchanger 3, which is a heat source side heat exchanger that becomes a condenser or an evaporator according to the operation mode, and an illustration for forcing the outside air to the outer surface of the outdoor heat exchanger 3 The blower which does not do is stored. The outdoor unit 100 is connected to the outside air processing unit 300 via a liquid pipe 52 and a gas pipe 51. In the cooling operation in which the refrigerant shown by the solid line in FIG. 1 flows, the first port 2a of the four-way valve 2 is the discharge side of the first compressor 1, the second port 2b is one end of the outdoor heat exchanger 3, and the third The port 2 c is connected to the suction side of the first compressor 1, and the fourth port 2 d is connected to the gas pipe 51.

  The indoor units 200a and 200b are indoor heat exchangers 5a and 5b, which are first load-side heat exchangers, and first pressure-reducing means capable of changing the opening to adjust refrigerant distribution to the indoor heat exchangers 5a and 5b. Electronic expansion valves 4a and 4b, a blower (not shown) for forcibly blowing room air to the outer surfaces of the indoor heat exchangers 5a and 5b, and piping for connecting them are incorporated. One end of each of the indoor heat exchangers 5a and 5b is connected to the outside air processing unit 300, and the other end is connected to the outside air processing unit 300 via the electronic expansion valves 4a and 4b. In this embodiment, two indoor units 200a and 200b are used, but one or three or more indoor units may be used.

  In the outside air processing unit 300, the second compressor 10 that boosts the refrigerant to the suction pressure of the first compressor 1, the four-way valve 11 that is the second flow path switching means, and the indoor heat that is the second load side heat exchanger. The exchanger 12, the electronic expansion valve 13 that is a second decompression means that can change the opening degree, and the first internal heat exchanger that exchanges heat between the outlet portion of the outdoor heat exchanger 3 and the suction portion of the first compressor 1 during the cooling operation. 14, a second internal heat exchanger 15 that exchanges heat between the outlet portion of the internal heat exchanger 14 and the suction portion of the second compressor 10, an electromagnetic valve 30 that is an opening / closing means for switching the flow path between the cooling operation and the heating operation, 31 and piping for connecting them are built in. The first port 11a of the four-way valve 11 is the discharge side of the second compressor 10, the second port 11b is one end of the indoor heat exchanger 12, the third port 11c is the suction side of the second compressor 10, and the fourth The ports 2d are connected to the gas pipe 51, respectively.

  The operation of the refrigeration cycle apparatus configured as described above will be described. First, the case where the cooling operation is performed will be described with reference to FIGS. 1 and 2. FIG. 2 shows the refrigerant state of symbols A to J shown in the refrigerant circuit of FIG. 1 on the Ph diagram. In the cooling operation, the indoor heat exchangers 5a and 5b in the indoor units 200a and 200b are set to have a high evaporation temperature, and the sensible heat load in the air-conditioning target space is mainly processed. On the other hand, the indoor heat exchanger 12 in the outside air processing unit 300 is set to have a low evaporation temperature, and the latent heat load in the air-conditioning target space is mainly processed. That is, the indoor heat exchangers 5a and 5b for processing the sensible heat have heat transfer areas sufficiently large with respect to the heat exchange amount for heat exchange of the indoor heat load, and the blower that blows air to the heat exchanger. It has an air volume and the refrigerant temperature of the heat exchanger is equal to or higher than the dew point temperature of the room air. As a result, it has a heat exchange capability in which a high evaporation temperature is set such that the temperature difference between the liquid refrigerant inside the heat exchanger and the room air is within 10 degrees. On the other hand, the indoor heat exchanger 12 for processing latent heat has a heat exchange processing capacity smaller than that of the heat exchanger of sensible heat treatment, for example, about 1/3 of the heat transfer area, and the refrigerant temperature is lower than the dew point temperature to perform dehumidification. . A low evaporation temperature is set such that the difference between the air temperature and the refrigerant temperature is 10 degrees or more.

  In the cooling operation, the four-way valve 2 inside the outdoor unit 100 is set so that the first port 2a and the second port 2b communicate with each other and the third port 2c and the fourth port 2d communicate with each other (solid line in FIG. 1). Moreover, the electromagnetic valves 30 and 31 in the outside air processing unit 300 are closed, and the opening degree of the electronic expansion valve 13 is such that an appropriate degree of superheat (for example, 5 to 10 ° C.) is obtained at the outlet of the indoor heat exchanger 12. The opening degree of the electronic expansion valves 4a and 4b in the indoor unit 200 is adjusted so that an appropriate degree of superheat (for example, 5 to 10 ° C.) is obtained at the outlets of the indoor heat exchangers 5a and 5b. The By setting such a degree of superheat or supercooling, the capacity of each heat exchanger can be fully exhibited.

  At this time, the high-temperature and high-pressure gas refrigerant discharged from the first compressor 1 passes through the first port 2a of the four-way valve 2 through the second port 2b (state B), and is heated by the outdoor heat exchanger 3 as a medium to be heated. It radiates heat to certain air (state C), passes through the liquid pipe 52 and the internal heat exchanger 14 (state D), and further passes through the internal heat exchanger 15 (state E). After that, a part of the refrigerant flows into the indoor unit 12 and processes the latent heat load of the air-conditioning target space (state F), passes through the internal heat exchanger 15 (state G), and passes through the second port 11b of the four-way valve 11. It flows into the second compressor 10 through the third port 11c. The refrigerant compressed by the second compressor 10 passes from the first port 11a of the four-way valve 11 through the fourth port 11d (state H) and merges into the gas pipe 51 (state J). The other part that has passed through the internal heat exchanger 15 flows into the indoor units 200a and 200b.

  The liquid refrigerant that has flowed into the indoor units 200a and 200b is decompressed by the electronic expansion valves 4a and 4b to become a gas-liquid two-phase refrigerant, and is uniformly distributed to the indoor heat exchangers 5a and 5b, for example. The gas-liquid two-phase refrigerant absorbs heat from indoor air (not shown) in the indoor heat exchangers 5a and 5b, and evaporates itself. This low-temperature and low-pressure gas refrigerant (state I) merges with the refrigerant discharged from the second compressor 10 in the outside air processing unit 300 (state J), and the merged refrigerant passes through the internal heat exchanger 14 to the gas pipe. 51, Return from the fourth port 2d of the four-way valve 2 to the suction side of the first compressor 1 through the third port 2c (state A). At this time, the indoor air sent to the indoor heat exchangers 5a and 5b by an indoor blower (not shown) is cooled by the low-temperature and low-pressure liquid refrigerant and blown into the room to cool the room. That is, during cooling operation, the engine is operated at two different low pressures, in other words, two different evaporation pressures.

  In this embodiment, by using the internal heat exchangers 14 and 15 connected in series, the enthalpy difference of the evaporator can be increased from ΔH1 to ΔH2, as shown in FIG. 2, and the operation is performed at a low evaporation temperature. Thus, the refrigerant flow rate Gr2 (compression work) on the lower stage side (latent heat treatment side) can be reduced, and the operation at the low evaporation temperature can be reduced as much as possible. When the internal heat exchanger is used, the refrigerant at the outlet of the evaporator is further superheated by the high-temperature refrigerant, so that the conventional HFC-based refrigerant has a problem that the discharge temperature increases with the intake temperature. In the case of carbon dioxide, the compression ratio at each stage is significantly lower than that of the HFC refrigerant, so that the compression work is reduced and the discharge temperature does not rise excessively. Therefore, using an internal heat exchanger in a two-stage compression refrigeration cycle using carbon dioxide is a measure for improving performance suitable for the refrigerant used.

  Next, the heating operation will be described with reference to FIGS. The internal heat exchangers 14 and 15 are not used during the heating operation. In this case, the four-way valve 2 in the outdoor unit 100 is set so that the first port 2a and the fourth port 2d communicate with each other, and the second port 2b and the third port 2c communicate with each other. 11 is set such that the first port 11a and the second port 11b communicate with each other, and the third port 11c and the fourth port 11d communicate with each other. Further, the electromagnetic valves 30 and 31 in the outside air processing unit 300 are opened, and the opening degree of the electronic expansion valve 13 is adjusted so that the outlet of the indoor heat exchanger 12 becomes an appropriate temperature according to the room temperature. The opening degree of the electronic expansion valves 4a and 4b in the 200 is adjusted so that the outlets of the indoor heat exchangers 5a and 5b have an appropriate temperature according to the room temperature.

  At this time, the refrigerant that has been compressed by the first compressor 1 and is in a supercritical state of high temperature and pressure flows from the first port 2a of the four-way valve 2 into the outside air processing unit 300 through the fourth port 2d and the gas pipe 51. The high-temperature and high-pressure refrigerant that has flowed into the outside air processing unit 300 passes through the electromagnetic valve 30 (state J), and partly flows into the indoor units 200a and 200b (state I). Here, heat is released to indoor air (not shown) to heat the room, and the temperature itself decreases. The medium-temperature and high-pressure refrigerant is decompressed by the electronic expansion valves 4a and 4b, enters a gas-liquid two-phase state, and flows into the outside air processing unit 300. The gas-liquid two-phase refrigerant that has flowed into the outside air processing unit 300 merges with the refrigerant from the electronic expansion valve 13 (state E), passes through the internal heat exchanger 15, the internal heat exchanger 14, and the liquid pipe 52, and is used as outdoor heat. It flows into the exchanger 3. However, the internal heat exchanger does not exchange heat as in cooling.

  On the other hand, the other part of the refrigerant that has passed through the electromagnetic valve 30 passes through the fourth port 11d and the third port 11c of the four-way valve 11 and is further compressed by the second compressor 10, and the first port of the four-way valve 11 is further compressed. It passes through the electromagnetic valve 31 (state F) through 11a and the second port 11b and flows into the indoor heat exchanger 12. The refrigerant radiated by the indoor heat exchanger 12 is decompressed by the electronic expansion valve 13 and merges with the refrigerant that has flowed into the outside air processing unit 300 from the electronic expansion valves 4a and 4b.

  The low-temperature and low-pressure liquid refrigerant flowing into the outdoor heat exchanger 3 absorbs heat from the outside air sent by an outdoor fan (not shown) and evaporates itself (state B). The evaporated gas refrigerant returns from the second port 2b of the four-way valve 2 to the suction side (state A) of the first compressor 1 through the third port 2c. Thus, during heating operation, the engine is operated at two different high pressures, in other words, two different supercritical pressures. That is, the refrigerant of the indoor heat exchanger 12 is a high-pressure and high-temperature refrigerant as compared with the refrigerant of the indoor heat exchangers 5a and 5b.

  A configuration example of another refrigeration cycle is shown in FIG. 1 differs from FIG. 1 in that the outlet refrigerant gas of the indoor heat exchangers 4a and 4b and the indoor heat exchanger 12 is used as the low-temperature heat source of the internal heat exchanger. In FIG. A part of this is decompressed by electronic expansion valves 16 and 17 which are decompression means, and a gas-liquid two-phase refrigerant is used. In FIG. 4, the internal heat exchanger 14 on the upstream side during cooling operation is cooled with a gas-liquid two-phase refrigerant in which a part of the liquid refrigerant is decompressed by the electronic expansion valve 16, and the internal heat exchanger 15 on the downstream side is internally heated. A part of the liquid refrigerant cooled by the exchanger 14 is cooled by the gas-liquid two-phase refrigerant decompressed by the electronic expansion valve 17.

  Specifically, in the cooling operation, the liquid refrigerant flowing into the outside air processing unit 300 from the liquid pipe 52 is a low-pressure gas-liquid two-phase refrigerant in which a part of the liquid refrigerant is decompressed by the electronic expansion valve 16 in the internal heat exchanger 14. Cooled by. On the other hand, the low-pressure gas-liquid two-phase refrigerant evaporates in the internal heat exchanger 14 and joins the gas pipe 51. A part of the liquid refrigerant cooled by the internal heat exchanger 14 is further cooled by the gas-liquid two-phase refrigerant decompressed by the electronic expansion valve 17 in the internal heat exchanger 15. On the other hand, the low-pressure gas-liquid two-phase refrigerant evaporates in the internal heat exchanger 15 and merges with the outlet portion of the indoor heat exchanger 12. Another part of the liquid refrigerant cooled by the internal heat exchanger 14 flows into the indoor units 200a and 200b without being cooled by the internal heat exchanger 15. Here, the opening degree of the electronic expansion valves 16 and 17 is controlled so that the degree of superheat at the low pressure side outlet of the internal heat exchangers 14 and 15 becomes an appropriate value (for example, the degree of superheat is 5 to 10 ° C.). . The superheat degree is calculated by, for example, installing a thermistor at the low pressure side inlet / outlet portion of the internal heat exchangers 14 and 15 (the inlet side is TH1 and the outlet side is TH2), and the superheat degree SH is calculated from the difference. (SH = TH2-TH1).

  In this example, a gas-liquid two-phase refrigerant in which a part of the liquid pipe 52 is decompressed by the electronic expansion valves 16 and 17 is used as a low-temperature heat source for the internal heat exchangers 14 and 15. Therefore, the enthalpy difference of the evaporator can be expanded without increasing the suction temperature of the first compressor 1 and the second compressor 10, and the low stage side (latent heat treatment side) operated at the low evaporation temperature can be increased. Refrigerant flow rate Gr2 (compression work) can be reduced, and low-efficiency operation at a low evaporation temperature can be reduced as much as possible. Although FIG. 4 shows an example in which the internal heat exchanger 15 cools the inlet portion of the indoor heat exchanger 12, the mainstream refrigerant that has passed through the internal heat exchanger 14 can be cooled in the same manner as in FIG. In the heating operation shown in FIG. 4, the electronic expansion valves 16 and 17 are fully closed, and the internal heat exchangers 14 and 15 are not used.

  Furthermore, the example which cools the exit part of the heat source side heat exchanger 3 with watering is demonstrated based on FIG. 5 as another structural example. In FIG. 5, the heat source side heat exchanger 3 in the outdoor unit 100 is divided into two, the heat exchanger arranged on the leeward side with respect to the air blown from the blower is 3a, and the heat exchanger arranged on the upwind side is 3b. And The refrigerant discharged from the compressor 1 first passes through the heat exchanger 3a, and then passes through the heat exchanger 3b. On the other hand, low-temperature water supplied as the feed water 42 is jetted from the nozzle 41 toward the heat exchanger 3b to cool the outlet portion 3b of the heat source side heat exchanger. Thus, the outlet part of the heat exchanger that becomes a radiator can be cooled by watering, and the outlet temperature of the heat exchanger can be lowered to improve the efficiency. If the water spray from the nozzle 41 is linked to the operation operation of the compressor, or the refrigerant temperature, the high pressure, the outside air temperature of the heat exchanger 3b is detected, or it is performed corresponding to the control operation of the indoor unit. It becomes more effective.

  FIG. 6 is another example in which the outlet of the heat source side heat exchanger 3 is cooled by watering. In FIG. 6, the row arranged on the leeward side is 3a, the row arranged on the leeward side is 3b, the refrigerant is flowed opposite to the flow direction of the wind, and the row arranged on the leeward side is cooled by watering. It is. In this configuration, since the heat transfer tubes arranged in the leeward row are cooled by water spray, and the heat transfer tubes arranged in the leeward row are cooled by air, the refrigerant is used in the leeward row and the leeward row. The temperature difference increases. In such a case, as shown in FIG. 7, if a heat blocking slit 43 for blocking heat transfer by heat conduction is provided between the leeward row and the leeward row, the heat generated by the temperature difference between the rows. Loss can be prevented. 6 and 7 show the case where the number of columns is two, the same effect can be obtained even when the number of columns is three or more. In this way, the heat exchanger composed of heat transfer tubes and fins is separated into a plurality of pieces as shown in FIG. 5, or the refrigerant flow flowing in the heat transfer tubes as shown in FIG. 6 is divided into a plurality of portions such as the inlet side and the outlet side. In any of the structures using integral fins, water is sprinkled on the refrigerant outlet side of the heat source side heat exchanger to improve efficiency.

  In this way, spraying water to the outlet of the heat source side heat exchanger can lower the refrigerant temperature, expand the enthalpy difference in the evaporator, and improve the performance. Carbon dioxide has a larger specific heat at the radiator outlet than an HFC-based refrigerant, and the effect of watering is larger than that of an HFC-based refrigerant. This performance improvement measure by watering is irrelevant to the configurations of the outdoor air processing unit 300 and the indoor unit 200, and can be widely applied to various refrigerant circuit configurations. Therefore, it is also possible to connect the internal heat exchangers 14 and 15 shown in FIG. 1 and FIG. 4 in series and use the watering and the internal heat exchanger in combination. Therefore, the efficiency is improved in a cycle that uses a refrigerant that is in a supercritical state without using a two-stage compression or in a refrigeration cycle that is not a refrigeration cycle that is divided into latent heat and sensible heat. By the way, since an internal heat exchanger is a form which heat-exchanges between refrigerant | coolants, for example, a double pipe heat exchanger is used and the heat exchange amount of about 0 to 20% of the heat exchange amount in the indoor heat exchangers 200a and 200b. Should be obtained. The form of the heat exchanger is not limited to the double tube heat exchanger, and for example, a heat exchanger having a shape in which a plate heat exchanger or a flat tube is bonded may be used.

  As described above, in the present embodiment, an internal heat exchanger is provided during the cooling operation for the two-stage compression refrigeration cycle apparatus that generates two different evaporation temperatures during the cooling operation and two different condensation temperatures during the heating operation. It can be used to provide a highly efficient refrigeration cycle apparatus. Also, two internal heat exchangers are provided in series at the outlet of the radiator, and the upstream internal heat exchanger is a low-pressure refrigerant of the indoor heat exchangers 5a and 5b having a high evaporation temperature for processing the sensible heat load, The internal heat exchanger on the downstream side is cooled by the low-pressure refrigerant of the indoor heat exchanger 12 having a low evaporation temperature for processing the latent heat load. Therefore, heat can be used in stages (cascade), and a highly efficient refrigeration cycle apparatus can be provided. Further, since the internal heat exchangers 14 and 15 are connected in series, the enthalpy difference of the evaporator can be increased from ΔH1 to ΔH2, and the refrigerant flow rate Gr2 (compression work) on the low stage side (latent heat treatment side) can be increased. It is possible to reduce the operation at a low evaporation temperature as much as possible and provide a highly efficient refrigeration cycle apparatus. Furthermore, by spraying water on the outlet portion of the heat source side heat exchanger, the refrigerant temperature can be lowered, the enthalpy difference can be expanded, and the performance can be improved. By using the internal heat exchanger in combination, a more efficient air conditioner can be obtained.

Next, a configuration example of the configuration of the refrigeration cycle apparatus according to the present invention, which is another measure for improving efficiency, will be described. FIG. 8 is a schematic diagram showing a refrigeration cycle apparatus different from those shown in FIGS. 1 and 4. In FIG. 8, an ejector is used that operates at two different evaporation temperatures during cooling operation and performs normal heating operation during heating operation. Type refrigeration cycle apparatus. During the cooling operation, the latent heat load is processed by the low-stage ejector 20, and the sensible heat load is processed by the high-stage first compressor 1. The refrigeration cycle apparatus includes an outdoor unit 100 that is a heat source side unit, indoors 200a and 200b that are first load side units, an outdoor air processing unit 300, a liquid pipe 52 and a gas pipe that connect the outdoor unit 100 and the outdoor air processing unit 300. 51. It is comprised from the piping which connects the external air processing unit 300 and indoor unit 200a, 200b. For example, carbon dioxide that is in a supercritical state at a critical temperature (about 31 ° C.) or higher is sealed as a refrigerant.

  In the outdoor unit 100, the first compressor 1, the four-way valve 2 as the first refrigerant flow switching means between the cooling operation and the heating operation, the outdoor heat exchanger 3 as the heat source side heat exchanger, and the outside air are forced A blower (not shown) for blowing air to the outer surface of the outdoor heat exchanger 3 is housed in the room. In the outside air processing unit 300, an ejector 20 that depressurizes the refrigerant to form wet steam in a two-phase state, an indoor heat exchanger 12 that is a second load side heat exchanger, an electronic expansion valve 13 that is a pressure reducing means, a gas-liquid A separator 19, a bypass flow path that guides the gas refrigerant separated by the gas-liquid separator 19 to the gas pipe 51 through the indoor heat exchanger 18 that is a third heat exchanger and the electronic expansion valve 32 that is a decompression unit; Piping for connecting them is built in. The indoor heat exchanger 18 is provided in order to prevent liquid return to the first compressor 1 when the separation in the gas-liquid separator 19 is insufficient, and the non-evaporated liquid from the gas-liquid separator 19 Evaporates in the indoor heat exchanger 18. The first port 2a of the four-way valve 2 is the discharge side of the compressor 1, the second port 2b is one end of the outdoor heat exchanger 3, the third port 2c is the suction side of the compressor 1, and the fourth port 2d is a gas. Each is connected to the pipe 51.

  The indoor units 200a and 200b include indoor heat exchangers 5a and 5b that are first load-side heat exchangers, electronic expansion valves 4a and 4b that depressurize refrigerant to be supplied to the indoor heat exchanger, A blower (not shown) for blowing air to the outer surfaces of the heat exchangers 5a and 5b and piping for connecting them are incorporated. One end of each indoor heat exchanger 5a, 5b is connected to the outside air processing unit 300, and the other end is connected to the outside air processing unit 300 via the electronic expansion valves 4a, 4b. In this embodiment, two indoor units 200a and 200b are used, but one or three or more indoor units may be used.

  In the outside air processing unit 300, the ejector 20, the indoor heat exchanger 12 that is the second load side heat exchanger, the electronic expansion valve 13 that is the second pressure-reducing means whose opening degree can be changed, and the piping for connecting them Is built-in.

Next, an internal structure diagram of the ejector 20 is shown in FIG. The ejector is a means for recovering expansion power that performs compression work by converting pressure energy into kinetic energy at the nozzle portion and sucking the suction flow to increase the suction pressure of the compressor. As shown in FIG. 9, it is comprised from a nozzle part, a mixing part, and a diffuser part. In the nozzle portion, the high-pressure fluid (drive flow) having the flow rate Gn and the pressure Pc is decompressed, and the speed increases. The driving flow becomes sonic at the nozzle throat, accelerates and expands to supersonic speed at the nozzle wide end, and reaches the nozzle outlet (pressure Ps, flow velocity Vn). In the mixing portion, the driving flow (flow velocity Vn) ejected from the nozzle outlet portion sucks the gas refrigerant from the suction portion, and is decelerated by mixing with the suction flow (flow velocity Ve), so that the pressure is restored to Pmix. Furthermore, the refrigerant pressure in the diffuser portion flows out the ejector recovered to P _D. The ejector 20 has a configuration in which the opening degree of the ejector 20 can be changed by a needle.

  Next, the operation of the refrigeration cycle apparatus configured as described above will be described. First, the case where the cooling operation is performed will be described with reference to FIGS. FIG. 10 shows the refrigerant state at symbols A to K shown in the refrigerant circuit of FIG. 8 on the Ph diagram. In the cooling operation, the indoor heat exchangers 5a and 5b in the indoor units 200a and 200b are set to have a high evaporation temperature, and the sensible heat load in the air-conditioning target space is mainly processed. On the other hand, the indoor heat exchanger 12 in the outside air processing unit 300 is set to have a low evaporation temperature, and the latent heat load in the air-conditioning target space is mainly processed.

  In the cooling operation, the four-way valve 2 inside the outdoor unit 100 is set so that the first port 2a and the second port 2b communicate with each other and the third port 2c and the fourth port 2d communicate with each other (solid line in FIG. 8). In addition, the electronic expansion valve 32 in the outside air processing unit 300 is set to an opening degree at which a liquid level is stably formed in the gas-liquid separator 19, and the opening degree of the electronic expansion valve 13 is the outlet of the indoor heat exchanger 12. It adjusts so that a suitable superheat degree (for example, 5-10 degreeC) may be obtained for a part. The opening degree of the electronic expansion valve 32 at which the liquid level is stably formed in the gas-liquid separator 19 is obtained as the opening degree through which the gas flow rate determined from the dryness of the refrigerant flowing into the gas-liquid separator 19 flows. Actually, the total refrigerant flow rate is obtained from the rotational speed of the compressor, the intake temperature, and the intake pressure, the dryness is obtained from the refrigerant temperature and pressure conditions, the gas flow rate is estimated, and the pressure difference before and after the electronic expansion valve 32 is calculated. It is only necessary to detect and calculate the opening degree from the gas flow rate and the pressure difference. In addition, the relationship between the operating conditions, such as environmental conditions such as outside air temperature and room temperature, operating conditions such as compressor speed, refrigerant pressure and temperature, and the opening, is determined in advance by experiment and calculation, and the opening is set. You may make it do. The opening degree of the electronic expansion valves 4a and 4b in the indoor units 200a and 200b is adjusted so that an appropriate degree of superheat (for example, 5 to 10 ° C.) is obtained at the outlets of the indoor heat exchangers 5a and 5b.

At this time, the high-temperature and high-pressure gas refrigerant discharged from the first compressor 1 passes through the first port 2a of the four-way valve 2 through the second port 2b (state B), and is heated by the outdoor heat exchanger 3 as a medium to be heated. The heat is radiated to a certain air (state C), depressurized by the liquid pipe 52 and the ejector 20 (state D), and flows into the gas-liquid separator 19. The gas-liquid two-phase refrigerant that has flowed into the gas-liquid separator 19 is separated into a gas refrigerant (state E) and a liquid refrigerant.
The separated gas refrigerant is decompressed by the electronic expansion valve 32 through the indoor heat exchanger 18, and joins the inlet of the gas pipe 51 (state I). On the other hand, a part of the separated liquid refrigerant is further depressurized by the electronic expansion valve 13 (state J), flows into the indoor heat exchanger 12, processes the latent heat load of the air-conditioning target space, and is then sucked into the ejector 20. The

  The other part of the separated liquid refrigerant flows into the indoor units 200a and 200b (state F) and is decompressed by the electronic expansion valves 4a and 4b to become a gas-liquid two-phase refrigerant (state G and pressure Pe). This gas-liquid two-phase refrigerant absorbs heat from indoor air (not shown) in the indoor heat exchangers 5a and 5b, and evaporates itself (state H). This low-temperature and low-pressure gas refrigerant (state H) merges with the refrigerant from the electronic expansion valve 32 in the outside air processing unit 300 (state I). The merged refrigerant returns from the gas pipe 51 and the fourth port 2d of the four-way valve 2 to the suction side of the first compressor 1 through the third port 2c (state A). At this time, the indoor air sent to the indoor heat exchangers 5a and 5b by an indoor blower (not shown) is cooled by the low-temperature and low-pressure liquid refrigerant and blown into the room to cool the room.

  In the example of the configuration in FIG. 8, the power consumption can be reduced by using the recovered power recovered by the ejector 20 instead of the compression power of the second compressor 10 illustrated in FIG. 1 and the like. Further, as shown in the structural diagram of FIG. 11, the heat exchanger 12 and the heat exchanger 18 may be integrated. In FIG. 11, the windward row of the heat exchanger is the heat exchanger 18, the leeward row is the heat exchanger 12, and the unevaporated liquid from the gas-liquid separator 19 is evaporated by the windward heat exchanger 18. The leeward heat exchanger 12 is configured to process the latent heat load of air. In this way, the outside air processing unit 300 can be configured in a compact manner by integrating the heat exchanger 12 and the heat exchanger 18 into an integrated structure.

  Next, the heating operation will be described with reference to FIG. During the heating operation, heating operation in a single stage by the first compressor 1 is performed. In this case, the four-way valve 2 inside the outdoor unit 100 is set so that the first port 2a and the fourth port 2d communicate with each other and the second port 2b and the third port 2c communicate with each other (dotted line in FIG. 8). Further, the electronic expansion valve 32 and the electronic expansion valve 13 in the outside air processing unit 300 are fully closed. The opening degree of the electronic expansion valves 4a and 4b in the indoor unit 200 is adjusted so that the outlets of the indoor heat exchangers 5a and 5b have an appropriate temperature corresponding to the room temperature.

  At this time, the refrigerant that has been compressed by the first compressor 1 and is in a supercritical state of high temperature and pressure flows from the first port 2a of the four-way valve 2 into the outside air processing unit 300 through the fourth port 2d and the gas pipe 51. The high-temperature and high-pressure refrigerant that has flowed into the outside air processing unit 300 flows into the indoor units 200a and 200b. Here, heat is released to indoor air (not shown) to heat the room, and the temperature itself decreases. The medium-temperature and high-pressure refrigerant is slightly decompressed by the electronic expansion valves 4 a and 4 b and flows into the outside air processing unit 300. The medium-temperature high-pressure refrigerant that has flowed into the outside air processing unit 300 passes through the gas-liquid separator 19, is depressurized by the ejector 20, passes through the liquid pipe 52, and flows into the outdoor heat exchanger 3.

  The low-temperature and low-pressure liquid refrigerant flowing into the outdoor heat exchanger 3 absorbs heat from the outside air sent by an outdoor fan (not shown) and evaporates itself. The evaporated gas refrigerant returns from the second port 2b of the four-way valve 2 to the suction side of the first compressor 1 through the third port 2c.

  By the way, the outside air processing unit 300 and the indoor unit 200 may be integrated. That is, the heat exchangers 5, 18, and 12 are stored together in one box, and the air from the blower, which is one air blowing means, is passed through each heat exchanger in parallel, in series, or in series and parallel to cool the air. Air conditioning such as heating, heating, or dehumidification can be performed. FIG. 12 is a structural diagram, in which the heat exchanger 5 that performs sensible heat treatment is disposed on the leeward side, and the heat exchanger 12 that performs latent heat treatment is disposed on the leeward side. Furthermore, the heat exchanger 12 and the heat exchanger 18 have an integral structure, and the heat exchanger 18 is arranged as the leeward row, and as a result, the heat exchanger 12 that performs the latent heat treatment is arranged as the leeward row. Thus, the system can be made compact by using the indoor unit 200 in which the outside air processing unit 300 and the indoor unit 200 are integrated. The outside air processing unit 300 is named because it can be arranged outside the room to process the outside air and blow out the air-conditioned air to the air conditioning area. However, in the case of an integrated heat exchanger configuration as shown in FIG. 12, indoor air can be sucked and blown into the room, that is, it can be provided inside an indoor unit provided in the air conditioning area. In this way, an integrated heat exchanger structure can be obtained with the structure in which the heat exchanger is separated as an indoor unit or the refrigerant flow to the heat transfer tube is separated.

  By the way, in the heat exchanger 5 which processes the sensible heat load in the indoor unit 200 or the indoor units 200a and 200b described above, the condensed water seen in the normal cooling operation is not generated. Therefore, a tray (drain pan) or drain pipe for receiving condensed water is not necessary. Further, since no dew condensation water is generated, it is possible to employ a special form of heat exchanger that has been difficult to use for conventional air conditioning. FIG. 13 is an example thereof, and is a structural diagram showing a corrugated fin tube heat exchanger using a flat tube heat exchanger as the heat transfer tube 45 and a corrugated fin 46 with slits as fins. The flat tube 45 is provided with a plurality of refrigerant channels therein. Conventionally, since condensed water is generated during cooling operation, the condensed water is trapped in the corrugated fins 46 and there is a problem that the performance of the heat exchanger is deteriorated. However, no practical product has been obtained. In the case of this structure, since the heat exchanger 5 processes only sensible heat, the conventional restriction condition of drainage of condensed water becomes unnecessary, and a high-performance heat exchanger can be used. By using such a high-performance heat exchanger, the outer dimensions of the heat exchanger can be reduced. In other words, by using heat exchangers having the same outer dimensions, the evaporation temperature can be increased, and a heat exchanger suitable for processing sensible heat can be provided.

  On the other hand, in order to process latent heat, the heat exchanger 12 employs a structure in which a plurality of plate fins that are easily treated with condensed water are arranged in the vertical direction. Further, it is preferable that a wire-shaped fin is wound around a thin heat transfer tube and the wire-shaped fin is stretched obliquely so that the condensed water easily flows. In this way, the heat exchanger that processes sensible heat and the heat exchanger that processes latent heat can be a combination of completely different heat transfer tube shapes and dimensions, fin shapes and dimensions, etc. No special consideration is required for the connecting portion, and it may be simply arranged in the order of the windward side and the leeward side.

  As described above, in the present embodiment, in the two-stage compression refrigeration cycle apparatus that generates two different evaporation temperatures during the cooling operation, it is possible to provide a highly efficient refrigeration cycle apparatus using the ejector during the cooling operation. . That is, the recovery power in the ejector 20 can be used instead of the second compressor 10 that processes the latent heat load, and the power consumption of the second compressor 10 is reduced, thereby providing a highly efficient refrigeration cycle apparatus. it can.

  Hereinafter, another refrigeration cycle apparatus of the present invention will be described. FIG. 14 is a schematic diagram showing the refrigeration cycle apparatus according to the present invention. In FIG. 14, a two-stage operation is performed at two different evaporating temperatures during cooling operation and heating operation at two different high pressures during heating operation. This is a compression type refrigeration cycle apparatus. The difference from the structure of FIG. 8 is that the latent heat load is processed by the ejector 20 during the cooling operation and the sensible heat load is processed by the first compressor 1 on the higher stage side. If the latent heat load is large, the ejector 20 It is a point that the latent heat load that cannot be processed can be processed by the second compressor 10 on the lower stage side. The difference from FIG. 8 is that an on-off valve 31 is provided, which is opened during cooling and closed during heating. The rest of the structure is almost the same as that shown in FIG.

  In the cooling operation, the four-way valve 2 inside the outdoor unit 100 is set so that the first port 2a and the second port 2b communicate with each other and the third port 2c and the fourth port 2d communicate with each other (solid line in FIG. 14). Further, the four-way valve 10 in the outside air processing unit 300 is set so that the first port 11a and the fourth port 11d communicate with each other and the second port 11b and the third port 11c communicate with each other (solid line in FIG. 14). The electronic expansion valve 32 is set to an opening degree at which a liquid level is stably formed in the gas-liquid separator 19, and the on-off valve 31 is fully opened. The opening degree of the electronic expansion valve 13 is adjusted so that an appropriate degree of superheat (for example, 5 to 10 ° C.) is obtained at the outlet of the indoor heat exchanger 12. The opening degree of the electronic expansion valves 4a and 4b in the indoor unit 200 is adjusted so that an appropriate degree of superheat (for example, 5 to 10 ° C.) is obtained at the outlets of the indoor heat exchangers 5a and 5b. The frequency of the second compressor is set to an appropriate number of rotations that can handle the shortage of the latent heat load, and the on-off valve 31 provided in the suction portion of the ejector 20 is opened.

  At this time, the high-temperature and high-pressure gas refrigerant discharged from the first compressor 1 passes through the first port 2a of the four-way valve 2 through the second port 2b (state B), and is heated by the outdoor heat exchanger 3 as a medium to be heated. The heat is radiated to a certain air (state C), depressurized by the liquid pipe 52 and the ejector 20 (state D), and flows into the gas-liquid separator 19. The gas-liquid two-phase refrigerant that has flowed into the gas-liquid separator 19 is separated into a gas refrigerant (state E) and a liquid refrigerant. The separated gas refrigerant is decompressed by the electronic expansion valve 32 through the indoor heat exchanger 18, and joins the discharge part of the second compressor 10. On the other hand, a part of the separated liquid refrigerant is decompressed by the electronic expansion valve 13 and flows into the indoor heat exchanger 12 (state J), passes through the on-off valve 31 after processing the latent heat load of the air-conditioning target space. And sucked by the ejector 20. When the latent heat load is large, a part of the refrigerant passing through the indoor heat exchanger 12 is sucked into the second compressor 10 from the second port 11b of the four-way valve 11 through the third port 11c, and from the first port 11a. It merges with the refrigerant from the electronic expansion valve 32 through the fourth port 11d and then merges with the inlet of the gas pipe 51 (state I).

  The other part of the separated liquid refrigerant flows into the indoor units 200a and 200b (state F) and is evenly distributed to the indoor heat exchangers 5a and 5b by the electronic expansion valves 4a and 4b (state G). . The distributed liquid refrigerant absorbs heat from indoor air (not shown) by the indoor heat exchangers 5a and 5b, and evaporates itself (state H). This low-temperature and low-pressure gas refrigerant joins the refrigerant that has processed the latent heat load in the outside air processing unit 300 and the refrigerant that has passed through the electronic expansion valve 32 (state I). The merged refrigerant returns from the gas pipe 51 and the fourth port 2d of the four-way valve 2 to the suction side of the first compressor 1 through the third port 2c (state A). At this time, the indoor air sent to the indoor heat exchangers 5a and 5b by an indoor blower (not shown) is cooled by the low-temperature and low-pressure liquid refrigerant and blown into the room to cool the room.

  In the configuration of FIG. 14, power consumption can be reduced by using the recovery power in the ejector 20 instead of the compression power of the second compressor 10 shown in FIG. 1. Further, since the latent heat load is processed by both the ejector 20 and the second compressor 10 on the lower stage side, it is possible to cope with a large latent heat load. The second compressor 10 is driven as follows. That is, the outside air processing unit 300 includes a blown air temperature / relative humidity detector and a controller, and calculates the absolute humidity of the outside air supplied to the indoor space based on the detection result. On the other hand, the indoor unit 200 includes an intake air temperature / relative humidity detector, and calculates the absolute humidity of the indoor space based on the detection result. When the absolute humidity calculated in the outdoor air processing unit is larger than the absolute humidity calculated in the indoor unit, it is determined that the latent heat load is large, and a start command for the second compressor 10 is issued from the control unit of the outdoor air processing unit. For example, proportional control is performed on the rotation speed of the second compressor 10 based on the difference in absolute humidity.

  Next, the heating operation will be described. During the heating operation, the heating operation is performed at two different high pressures using the first compressor 1 and the second compressor 10. In this case, the four-way valve 2 inside the outdoor unit 100 is set so that the first port 2a and the fourth port 2d communicate with each other and the second port 2b and the third port 2c communicate with each other (dotted line in FIG. 14). The four-way valve 11 inside the outside air processing unit 300 is set so that the first port 11a and the second port 11b communicate with each other and the third port 11c and the fourth port 11d communicate with each other. Further, the open / close valve 31 in the outside air processing unit 300 is closed, and the electronic expansion valve 32 is fully closed. The opening degree of the electronic expansion valve 13 is adjusted to an appropriate temperature corresponding to the room temperature at the outlet of the indoor heat exchanger 12, and the opening degree of the electronic expansion valves 4a and 4b in the indoor unit 200 is determined based on the indoor heat. The outlets of the exchangers 5a and 5b are adjusted so as to have an appropriate temperature corresponding to the room temperature.

  At this time, the refrigerant that has been compressed by the first compressor 1 and is in a supercritical state of high temperature and high pressure flows from the first port 2a of the four-way valve 2 into the outside air processing unit 300 through the fourth port 2d and the gas pipe 51. Some of the high-temperature and high-pressure refrigerant that has flowed into the outside air processing unit 300 flows into the indoor units 200a and 200b. Here, heat is released to indoor air (not shown) to heat the room, and the temperature itself decreases. This medium-temperature and high-pressure refrigerant passes through the electronic expansion valves 4 a and 4 b and flows into the outside air processing unit 300. The refrigerant that has flowed into the outside air processing unit 300 merges with the refrigerant from the electronic expansion valve 13, passes through the gas-liquid separator 19, is decompressed by the ejector 20, passes through the liquid pipe 52, and flows into the outdoor heat exchanger 3. To do.

  On the other hand, the other part passes through the fourth port 11d and the third port 11c of the four-way valve 11, is further compressed by the second compressor 10, and passes through the first port 11a and the second port 11b of the four-way valve 11. It flows into the indoor heat exchanger 12. The refrigerant radiated by the indoor heat exchanger 12 is decompressed by the electronic expansion valve 13 and merges with the refrigerant that has flowed into the outside air processing unit 300 from the electronic expansion valves 4a and 4b.

  The low-temperature and low-pressure liquid refrigerant flowing into the outdoor heat exchanger 3 absorbs heat from the outside air sent by an outdoor fan (not shown) and evaporates itself. The evaporated gas refrigerant returns from the second port 2b of the four-way valve 2 to the suction side of the first compressor 1 through the third port 2c.

  As described above, in this configuration, in the two-stage compression refrigeration cycle apparatus that generates two different evaporation temperatures during the cooling operation, it is possible to provide a highly efficient refrigeration cycle apparatus using the ejector during the cooling operation. Further, when the latent heat load cannot be processed with the recovery power of the ejector, the assist operation with the second compressor 10 can be performed, and a refrigeration cycle apparatus that can cope with a wide range of dehumidifying loads can be provided. Therefore, a decrease in efficiency can be suppressed even when carbon dioxide is used.

  Hereinafter, another refrigeration cycle apparatus of the present invention will be described. FIG. 15 is a schematic diagram showing this refrigeration cycle apparatus. In FIG. 15, an expander-based refrigeration cycle that operates at two different evaporating temperatures during cooling operation and operates at two different high pressures during heating operation. The second compressor 10 is driven by the recovery power of the expander 22. During the cooling operation, the low-stage second compressor 10 processes the latent heat load, and the high-stage first compressor 1 processes the sensible heat load. This refrigeration cycle apparatus connects an outdoor unit 100 that is a heat source side unit, indoors 200a and 200b that are first load side units, an outdoor air processing unit 300 that is a second load side unit, and the outdoor unit 100 and the outdoor air processing unit 300. The liquid pipe 52 and the gas pipe 51 are connected to the outside air processing unit 300 and the indoor units 200a and 200b. For example, carbon dioxide that is in a supercritical state at a critical temperature (about 31 ° C.) or higher is sealed as a refrigerant.

  In the outdoor unit 100, the first compressor 1, the four-way valve 2 as the first refrigerant flow switching means between the cooling operation and the heating operation, the outdoor heat exchanger 3 as the heat source side heat exchanger, and the outside air are forced A blower (not shown) for blowing air to the outer surface of the outdoor heat exchanger 3 is housed in the room. In the outside air processing unit 300, an expander 22 that depressurizes the refrigerant to form wet steam in a two-phase state, a four-way valve 21 that controls the refrigerant flow direction of the expander 22, and a second flow path between the cooling operation and the heating operation. The gas refrigerant separated by the four-way valve 11 that is the switching means, the indoor heat exchanger 12 that is the second load side heat exchanger, the electronic expansion valve 13 that is the decompression means, the gas-liquid separator 19, and the gas-liquid separator 19 , A bypass passage that leads to the discharge section of the second compressor 10 via the third heat exchanger 18 and the electronic expansion valve 32, and the recovery power and the rotational speed of the expander 22 are the compression power and rotation of the second compressor 10. Electronic expansion valves 33 and 34 whose opening degree can be changed to match the number and piping for connecting them are incorporated. The first port 21a of the four-way valve 21 is a liquid pipe 52, the second port 21b is an inlet of the expander 22, the third port 21c is one end of the indoor units 200a and 200b, and the fourth port 21d is a gas-liquid separator. 19 is connected to an electronic expansion valve 34 at the liquid side outlet. Since the other four-way valves 2 and 11 are set in the same manner as in the second embodiment, detailed description thereof is omitted.

  The indoor units 200a and 200b include indoor heat exchangers 5a and 5b that are first load-side heat exchangers, electronic expansion valves 4a and 4b that depressurize refrigerant to be supplied to the indoor heat exchanger, A blower (not shown) for blowing air to the outer surfaces of the heat exchangers 5a and 5b and piping for connecting them are incorporated. One end of the indoor heat exchangers 5a and 5b is connected to the outside air processing unit 300, and the other end is connected to the outside air processing unit via the electronic expansion valves 4a and 4b.

  Next, the operation of the refrigeration cycle apparatus configured as described above will be described. First, a case where the cooling operation is performed will be described with reference to FIGS. 15 and 16. FIG. 16 shows the refrigerant state at symbols A to L shown in the refrigerant circuit of FIG. 15 on the Ph diagram. In the cooling operation, the indoor heat exchangers 5a and 5b in the indoor units 200a and 200b are operated at a high evaporation temperature, and the sensible heat load in the air-conditioning target space is mainly processed. On the other hand, the indoor heat exchanger 12 in the outside air processing unit 300 is operated at a low evaporation temperature, and the latent heat load in the air-conditioning target space is mainly processed.

  In the cooling operation, the four-way valve 2 inside the outdoor unit 100 is set so that the first port 2a and the second port 2b communicate with each other and the third port 2c and the fourth port 2d communicate with each other (solid line in FIG. 15). In addition, the electronic expansion valve 32 in the outside air processing unit 300 is set to an opening degree at which a liquid level is stably formed in the gas-liquid separator 19, and the opening degree of the electronic expansion valve 13 is the outlet of the indoor heat exchanger 12. It adjusts so that a suitable superheat degree (for example, 5-10 degreeC) may be obtained for a part. The opening degree of the electronic expansion valves 4a and 4b in the indoor unit 200 is adjusted so that an appropriate degree of superheat (for example, 5 to 10 ° C.) is obtained at the outlets of the indoor heat exchangers 5a and 5b. The opening degree of the electronic expansion valve 33 provided so as to bypass the expander 22 and the opening degree of the electronic expansion valve 34 provided on the downstream side of the gas-liquid separator 19 are the same as those of the expander 22 and the second compressor 10. The speed and power are adjusted to match.

Specifically, if the refrigerant flow rate passing through the expander 22 is Gr and the enthalpy difference at the inlet / outlet of the expander 22 is ΔH1, the recovered power We in the expander 22 is expressed by the following equation (1).
We = Gr × ΔH1 (1)
Similarly, the compression work W2 in the second compressor is expressed by the following equation (2), where the refrigerant flow rate is Gr2 and the enthalpy difference in the second compressor 10 is ΔH2.
W2 = Gr2 × ΔH2 (2)
Since the recovered power is equal to the compression work in the second compressor 10 (We = W2), the expression (3) is obtained from the expressions (1) and (2).
Gr2 = Gr × (ΔH1 / ΔH2) (3)
Here, ΔH1 / ΔH2 in the equation (3) is a ratio of the enthalpy difference of the expander to the enthalpy difference of the compressor.

On the other hand, the expander 22 and the second compressor 10 are connected coaxially, and the second compressor 10 rotates at the same rotational speed as the expander 22. As an example, both the expander 22 and the second compressor 10 are of a scroll type that is a positive displacement fluid machine with a constant displacement volume, and the displacement volume ratio is ε (= second compressor displacement volume / expansion chamber displacement volume). = Vc / Ve), and the suction densities of the expander 22 and the second compressor 10 are ρe and ρc, respectively, the equation (4) can be obtained from the condition of constant rotation speed.
Gr2 = Gr × ε × (ρc / ρe) (4)
From equations (3) and (4), equation (5) is obtained.
ρc / ρe = (ΔH1 / ΔH2) / ε (5)
From the above, the expression (5) is established so that any one of the suction density ρc and the enthalpy difference ΔH2 of the second compressor 10, the suction density ρe of the expander 10, the inlet and outlet enthalpy difference ΔH1, and ε (= Vc / Ve) is established. Need to control. For example, an electronic expansion valve 33 may be provided in the expander 22 and the flow rate passing through the expander 22 may be controlled. This corresponds to adjusting ε in equation (5). Note that ρc, ρe, ΔH1, and ΔH2 can be easily estimated by detecting the pressure and temperature of the refrigerant circuit and using the physical properties of the refrigerant.

  If only the adjustment of the opening degree of the electronic expansion valve 33 does not hold the formula (5), and an imbalance occurs between the recovery power of the expander 22 and the compression power of the second compressor 10, the opening degree of the electronic expansion valve 34 Is appropriately controlled so that the expression (5) is satisfied. That is, the opening degree of the electronic expansion valve 34 is adjusted so that the expression (5) is satisfied, and the pressure difference ΔPe between the expander outlet and the evaporator inlet is adjusted.

  In the present embodiment, the example in which the opening degree of the electronic expansion valve 34 is adjusted and the expression (5) is established is shown, but the present invention is not limited to this, and the electronic expansion valves 4a in the indoor units 200a and 200b You may comprise so that the opening of 4b may be adjusted and Formula (5) may be materialized.

  At this time, the high-temperature and high-pressure gas refrigerant discharged from the first compressor 1 passes through the first port 2a of the four-way valve 2 through the second port 2b (state B), and is heated by the outdoor heat exchanger 3 as a medium to be heated. Heat is dissipated to a certain air (state C), passes through the liquid pipe 52, passes through the first port 21a to the second port 21b of the four-way valve 21, and is decompressed by the expander 22 (state D). Inflow. The gas-liquid two-phase refrigerant that has flowed into the gas-liquid separator 19 is separated into a gas refrigerant (state E) and a liquid refrigerant. The separated gas refrigerant is decompressed by the electronic expansion valve 32 through the indoor heat exchanger 18, and joins the discharge part of the second compressor 10. On the other hand, the separated liquid refrigerant is decompressed to some extent by the electronic expansion valve 34, passes through the third port 21 c from the fourth port 21 d of the four-way valve 21 (state F), and a part of the liquid refrigerant is further decompressed by the electronic expansion valve 13. (State J), after flowing into the indoor heat exchanger 12 and processing the latent heat load of the air-conditioning target space (State K), the second compressor 10 passes from the second port 11b of the four-way valve 11 through the third port 11c. Sucked into.

  The other part of the separated liquid refrigerant flows into the indoor units 200a and 200b (state F) and is equally distributed to the indoor heat exchangers 5a and 5b by the electronic expansion valves 4a and 4b (state G). The distributed refrigerant absorbs heat from indoor air (not shown) in the indoor heat exchangers 5a and 5b, and evaporates itself (state H). This low-temperature and low-pressure gas refrigerant (state H) merges with the refrigerant discharged from the second compressor 10 and the refrigerant from the electronic expansion valve 32 in the outside air processing unit 300 (state I). The merged refrigerant returns from the gas pipe 51 and the fourth port 2d of the four-way valve 2 to the suction side of the first compressor 1 through the third port 2c (state A). At this time, the indoor air sent to the indoor heat exchangers 5a and 5b by an indoor blower (not shown) is cooled by the low-temperature and low-pressure liquid refrigerant and blown into the room to cool the room.

  As described above, since the recovered power recovered by the expander 22 is used as the compression power of the second compressor 10, the lower-stage compression power can be reduced and the power consumption can be reduced as compared with the two-stage compression method. Can do.

  Next, the heating operation will be described. During the heating operation, the heating operation is performed with two types of high pressures using the first compressor 1 and the second compressor 10. During the heating operation, the four-way valve 2 inside the outdoor unit 100 is set so that the first port 2a and the fourth port 2d communicate with each other and the second port 2b and the third port 2c communicate with each other (dotted line in FIG. 15). ). The four-way valve 11 in the outside air processing unit 300 is set so that the first port 11a and the second port 11b communicate with each other and the third port 11c and the fourth port 11d communicate with each other. The electronic expansion valve 32 is fully closed, and the electronic expansion valve 13 is set to an opening at which the outlet of the indoor heat exchanger 12 has an appropriate temperature corresponding to the room temperature. Similarly, the opening degree of the electronic expansion valves 4a and 4b in the indoor unit 200 is adjusted so that the outlets of the indoor heat exchangers 5a and 5b have an appropriate temperature corresponding to the room temperature.

  At this time, the refrigerant that has been compressed by the first compressor 1 and is in a supercritical state of high temperature and high pressure flows from the first port 2a of the four-way valve 2 into the outside air processing unit 300 through the fourth port 2d and the gas pipe 51. Some of the high-temperature and high-pressure refrigerant that has flowed into the outside air processing unit 300 flows into the indoor units 200a and 200b. Here, heat is released to indoor air (not shown) to heat the room, and the temperature itself decreases. This medium-temperature and high-pressure refrigerant passes through the electronic expansion valves 4 a and 4 b and flows into the outside air processing unit 300. The refrigerant that has flowed into the outside air processing unit 300 merges with the refrigerant from the electronic expansion valve 13, flows from the third port 21 c of the four-way valve 21 through the second port 21 b, and flows into the expander 22. The refrigerant depressurized by the expander 22 flows into the gas-liquid separator 19, passes through the electronic expansion valve 34, passes through the liquid pipe 52 through the first port 21 a from the fourth port 21 d of the four-way valve 21, and the outdoor heat. It flows into the exchanger 3.

  On the other hand, the other part that has passed through the gas pipe 51 passes through the fourth port 11d and the third port 11c of the four-way valve 11, and is further compressed by the second compressor 10, and the first port 11a of the four-way valve 11 is further compressed. It flows into the indoor heat exchanger 12 through the second port 11b. The refrigerant radiated by the indoor heat exchanger 12 is decompressed by the electronic expansion valve 13 and merges with the refrigerant that has flowed into the outside air processing unit 300 from the electronic expansion valves 4a and 4b.

  The low-temperature and low-pressure liquid refrigerant flowing into the outdoor heat exchanger 3 absorbs heat from the outside air sent by an outdoor fan (not shown) and evaporates itself. The evaporated gas refrigerant returns from the second port 2b of the four-way valve 2 to the suction side of the first compressor 1 through the third port 2c.

  As described above, in the present embodiment, in the two-stage compression refrigeration cycle apparatus that generates two different evaporation temperatures during the cooling operation, the carbon dioxide refrigerant having a large adiabatic heat drop is used and the expansion power on the high-pressure gas side is increased. 14, that is, in the ejector of FIG. 14, the high pressure gas drive flow is used to boost the pressure of the refrigerant from the second load heat exchanger, and in FIG. 15, the second compression on the lower stage side using the recovered power in the expander 22. Since the compressor 10 is driven to increase the pressure of the refrigerant in the second load side heat exchanger, the compression power of the second compressor 10 becomes unnecessary, and a highly efficient refrigeration cycle apparatus can be provided. Moreover, since the compression power of the 2nd compressor 10 used as the high stage side can be reduced also at the time of heating operation, a highly efficient air conditioner can be provided also when carbon dioxide is used. In the description of the cycle of FIG. 8, FIG. 14 and FIG. 15, each load side heat exchanger is described in a separated form, and the load device has been described as being different like an outside air processing unit and an indoor unit. These may be arranged as different load devices, for example, outdoors and indoors, or as a single box, such as a wall-mounted indoor unit, ceiling-embedded cassette type air conditioner, floor-standing indoor unit, etc. There is no problem with the structure. In that case, components forming the refrigerant cycle such as each expansion valve, on-off valve, ejector, expander, and second compressor may be housed in the box or provided separately.

  In the example of FIG. 15 of the present invention, since the compression power of the second compressor 10 is linked with the compression power of the first compressor 1, only the rotation speed of the second compressor is increased when the latent heat load is increased. The latent heat load cannot be processed by increasing That is, since the rotational speed of the first compressor is increased as the latent heat load increases, the sensible heat treatment capacity is also increased at the same time. However, if a certain amount of air conditioning load (variation in the ratio between the sensible heat load and the latent heat load) can be predicted in advance, the refrigerant circuit can be simplified and power consumption can be reduced by applying this system. .

  By the way, in the above description, the example in which the outlet portion of the outdoor heat exchanger 3 is cooled by watering during the cooling operation to improve the performance has been shown. Similarly, the indoor heat exchangers 5a and 5b and the indoor heat are also used during the heating operation. High performance and high functionality can be realized by cooling the outlet of the exchanger 12 with water supply. In FIG. 17, a supercooling heat exchanger 53 is provided at the outlet of the indoor heat exchanger 12 during heating operation, and the refrigerant exiting the indoor heat exchanger 12 is cooled by the supercooling heat exchanger 53 and simultaneously supplied as a cold heat source. This is an example of increasing the temperature of water. The supplied water is water supplied to the humidifier, and the humidifier operates during heating operation such as in winter. According to the configuration of the present invention, the supply water supplied to the humidifier can be preheated with the refrigerant, so that the humidification amount (water evaporation) of the humidifier can be increased. Or the heater input of the humidifier conventionally required for preheating water supply can be reduced, and an energy saving effect can be obtained. Specifically, as shown in FIG. 17, a supercooling heat exchanger 53 is provided between the indoor heat exchanger 12 and the electronic expansion valve 13 that are on the high pressure side during heating, and vaporization is performed on the outlet side of the indoor air. A type humidifier is provided.

  The cooling water source of the supercooling heat exchanger 53 uses the feed water 42 supplied to the feed water tank 47 serving as a humidification source. The refrigerant that has passed through the indoor heat exchanger 12 is cooled by the feed water 42 in the supercooling heat exchanger 53 and flows into the electronic expansion valve 13. On the other hand, the temperature of the water supply 42 rises in the supercooling heat exchanger 53 and flows into the water supply tank 47. A humidifying element 48 is installed in the water supply tank 47. After the indoor air receives heat from the indoor heat exchanger 12 and rises in temperature, the humidity rises with moisture evaporated by the humidifying element 48 and blows out into the room. Is done. At this time, in the present invention, the water temperature in the water supply tank 47 and the humidifying element 48 can be increased, and the amount of humidification can be increased by increasing the saturation absolute humidity.

  From the above, it is possible to simultaneously realize an increase in the amount of humidification during heating operation and a performance improvement by cooling the outlet portion of the indoor heat exchanger 12, and a high-performance and high-performance refrigeration cycle apparatus can be obtained. In addition, although the example of the vaporization type humidifier was shown above, it is not restricted to this, It can apply also to the heater type humidifier which raises water temperature with a heater and humidifies. In this case, the power consumption of the heater necessary for obtaining a predetermined humidification amount can be reduced. Moreover, although the example which raises feed water temperature was shown, cooling the exit part, ie, radiator outlet part, of the indoor heat exchanger 12 which is a condenser, it does not restrict to this. That is, when it is desired to increase the amount of humidification, heat supply is exchanged with the radiator inlet, or the radiator inlet and outlet are exchanged at the same time or switched as necessary, and the water supply temperature is changed. You may make it raise and increase a humidification amount. Thereby, water supply can be heated up and the power consumption required for humidification can be reduced. In other words, it can be humidified even if the heating capacity is slightly reduced.

  As described above, the refrigeration cycle apparatus shown in FIGS. 1 and 4 of the present invention is provided with the internal heat exchanger that cools the outlet portion of the heat source side heat exchanger during the cooling operation, and therefore is efficient even when carbon dioxide is used. High refrigeration cycle apparatus can be obtained. As described above, in the present invention, carbon dioxide has been described as an example of the refrigerant. However, a mixed refrigerant containing at least a part of carbon dioxide may be used, or a refrigerant such as hydrofluorocarbon may be used as the second compressor by an ejector or an expander. The efficiency improvement effect for other than the configuration that drives the refrigeration cycle, for example, cooling the refrigerant at the outlet side of the radiator with an internal heat exchanger or watering, and the refrigeration cycle configuration that separates the latent heat processing and sensible heat processing Needless to say, this is not limited to the carbon dioxide refrigerant.

  In addition, the refrigeration cycle apparatus according to FIGS. 5 and 6 of the present invention connects at least the first compressor, the heat source side heat exchanger, and the first load side heat exchanger with piping, and uses carbon dioxide as a refrigerant. Since the outlet of the heat source side heat exchanger is cooled by spraying water, a highly efficient refrigeration cycle apparatus can be obtained even when carbon dioxide is used.

  The refrigeration cycle apparatus according to the present invention is provided with a first flow path switching means, a second flow path switching means, a second compressor, and a second load side heat exchanger, and is capable of switching between a cooling operation and a heating operation. In the cycle device, since carbon dioxide is used as a refrigerant and an internal heat exchanger for cooling the outlet portion of the heat source side heat exchanger during cooling operation is provided, a highly efficient refrigeration cycle device even when carbon dioxide is used. Can be obtained.

  In the refrigeration cycle apparatus according to the present invention, the internal heat exchanger is composed of two parts, a first internal heat exchanger and a second internal heat exchanger, and the first internal heat exchanger and the second internal heat exchanger are provided. Since they are connected in series, cascade use of heat can be realized, and a highly efficient refrigeration cycle apparatus can be provided even when carbon dioxide is used.

  Further, the refrigeration cycle apparatus according to the present invention uses the low-pressure refrigerant of the first load-side heat exchanger as the cooling heat source of the first internal heat exchanger and the second cooling heat source of the second internal heat exchanger during the cooling operation. Since the low-pressure refrigerant of the load-side heat exchanger is used, the use of heat cascade can be realized, and a highly efficient refrigeration cycle apparatus can be provided even when carbon dioxide is used.

  The refrigeration cycle apparatus according to the present invention includes at least a first compressor, a first flow path switching means, a heat source side heat exchanger, an ejector, a gas-liquid separator, a first load side heat exchanger, and a second load side heat. In a refrigeration cycle apparatus configured by connecting exchangers with piping and capable of switching between cooling and heating operation, carbon dioxide is used as the refrigerant, and the refrigerant flow rate of the second load side heat exchanger that has a low evaporation temperature during the cooling operation Is sucked by the ejector, the power of the second compressor becomes unnecessary, and a highly efficient refrigeration cycle apparatus can be obtained.

  Further, the refrigeration cycle apparatus according to the present invention is provided with a second compressor, a second flow path switching means, and a third flow path switching means, and assists the recovery power of the ejector with the compression power of the second compressor during the cooling operation. Therefore, a refrigeration cycle apparatus that can cope with a wide range of latent heat loads can be obtained.

  The refrigeration cycle apparatus according to the present invention includes at least a first compressor, a first flow path switching means, a heat source side heat exchanger, an expander, a second compressor driven by the expander, a gas-liquid separator, Since the first load side heat exchanger and the second load side heat exchanger are connected by piping, the compression power of the second compressor can be reduced, and a highly efficient refrigeration cycle apparatus can be obtained.

  In the refrigeration cycle apparatus according to the present invention, during the heating operation, the outlet portion of the first load side heat exchanger or the second load side heat exchanger is cooled with water, while the hot water whose temperature has been increased is used as a humidification source. Therefore, the amount of humidification can be increased while cooling the outlet of the radiator, and a high-performance and high-performance refrigeration cycle apparatus can be obtained.

  The present invention has been described by taking an air conditioner that can be switched between cooling and heating as an example, but it is naturally a refrigeration cycle that can be used in various air conditioners such as a dedicated cooling unit or an air conditioner that includes cooling and introduction of outside air. It is. Furthermore, the structures of the heat exchangers 5, 18, and 12 can be freely combined. Since the heat exchangers 5 and 18 that mainly process sensible heat have a refrigerant temperature that is equal to or higher than the dew point temperature of the room air, dew condensation is unlikely to occur and a simple drain processing structure may be used. Therefore, it is not necessary to consider the structure of water flow on the fin surface, such as sandwiching corrugated fins between flat heat transfer tubes, and it is possible to easily receive drainage, and the arch structure in which the heat exchanger surrounds the blower from the top is free. You can choose. On the other hand, the heat exchanger that processes latent heat needs to allow drain water to flow properly to the water storage part, and is structured to spray water to the outlet part of the first load side heat exchanger or the second load side heat exchanger that functions as a condenser during heating. Then, a deep drain water storage structure like the water storage tank 47 with respect to the humidification element 48 of FIG. 17 is required for the spraying of water and the resulting water treatment structure. Although these heat exchangers have mainly been described as having different structures, that is, heat transfer tubes and fins having different dimensions and shapes, the refrigerant flow that is the path of the heat transfer tubes attached to the same fin as shown in FIG. It is good also as a thing of each role of each heat exchanger by changing only a path.

  DESCRIPTION OF SYMBOLS 1 1st compressor, 2, 11, 21 Four-way valve, 3, 3a, 3b Heat source side heat exchanger, 4a, 4b, 16, 17, 32, 33, 34 Electronic expansion valve, 18 3rd heat exchanger, 19 Gas-liquid separator, 20 ejector, 5a, 5b first load side heat exchanger, 10 second compressor, 12 indoor unit, 13 electronic expansion valve, 14, 15 internal heat exchanger, 31 on-off valve, 41 watering nozzle, 42 Water supply, 43 Heat insulation slit, 45 Heat transfer tube, 46 Corrugated fin, 47 Water supply tank, 48 Humidification element, 51 Gas piping, 52 Liquid piping, 53 Supercooling heat exchanger, 100 Outdoor unit, 200a, 200b Indoor unit, 300 Outside air processing unit.

Claims (6)

A heat source machine having a first compressor that discharges a refrigerant that is in a supercritical state, first flow path switching means that can be switched between a cooling operation and a heating operation, and a heat source side heat exchanger;
A load device having a first pressure reducing means and a first load side heat exchanger;
An expander that is provided in a first pipe that supplies a refrigerant during cooling operation from the heat source unit to the load device, and that is driven by a high-pressure refrigerant;
A gas-liquid separator provided in the first pipe for gas-liquid separation;
A first expansion valve provided to bypass the expander by bypassing the refrigerant from the heat source side heat exchanger to the gas-liquid separator;
A second expansion valve provided on the downstream side of the liquid refrigerant of the gas-liquid separator,
The second compressor driven by the expander increases the pressure of the refrigerant that has become low pressure by the second decompression means and the second load side heat exchanger, and the pressure becomes high by the second compressor. The refrigerant is sucked into the first compressor through a second pipe that supplies the refrigerant from the load device to the heat source unit during the cooling operation.
Before the first expansion valve SL adjusts the degree of opening so as to match the power of the previous SL expander and the second compressor,
At least one of the second expansion valve and the first pressure reducing means adjusts the opening degree so that the powers match when the powers do not match only by adjusting the opening degree of the first expansion valve. A refrigeration cycle apparatus characterized by: The second pressure reducing means and the second load-side heat exchanger are provided via a second flow path switching means and a second compressor provided between the first pipe and the second pipe. The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is provided. An opening / closing valve that adjusts an opening degree so as to stabilize the liquid level of the gas-liquid separator, and a bypass circuit that bypasses the refrigerant from the gas-liquid separator is provided in the second pipe. The refrigeration cycle apparatus according to any one of claims 1 and 2. An internal heat exchanger that is provided in the vicinity of the outlet portion of the heat source side heat exchanger and cools the outlet portion refrigerant of the heat source side heat exchanger with a refrigerant having a pressure lower than that of the outlet portion refrigerant of the heat source side heat exchanger during cooling operation. When,
The refrigeration cycle apparatus according to any one of claims 1 to 3, further comprising: The heat source side heat exchanger that condenses the refrigerant discharged from the first compressor, a part of the refrigerant outlet side of the first load side heat exchanger, or another heat exchanger connected to the refrigerant outlet side, The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is sprayed or supplied with water. The water sprayed or supplied to at least one of the refrigerant outlet side and the refrigerant inlet side of the first load side heat exchanger that condenses the refrigerant discharged from the first compressor is supplied to the humidifier. Item 5. The refrigeration cycle apparatus according to any one of Items 1 to 4.

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