JP2008051474A - Supercritical refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a supercritical refrigerating cycle device capable of preventing the fall of a coefficient of performance even under a change in the operating state of an evaporator. <P>SOLUTION: The vapor compression type supercritical refrigerating cycle device wherein high pressure in a refrigerating cycle becomes the critical pressure of a refrigerant or higher, is provided with a plurality of high pressure side branch passages 121, 122 branching off on the refrigerant lower reaches of a radiator 120; a plurality of pressure reducers 131, 132 reducing the pressure of a refrigerant flowing in the plurality of high pressure side branch passages 121, 122; a plurality of evaporators 141, 142 evaporating the refrigerant flowing out of the plurality of pressure reducers 131, 132 to flow out to the compressor 110 side; and a plurality of internal heat exchangers 171, 172 exchanging heat between a high pressure refrigerant flowing from a branch point A of the high pressure side branch passages 121, 122 out of the plurality of high pressure side branch passages 121, 122 to the plurality of pressure reducers 131, 132, and a low pressure refrigerant flowing out of the plurality of evaporators 141, 142. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a supercritical refrigeration cycle apparatus including a plurality of evaporators using a refrigerant whose refrigerant pressure on the high pressure side is in a supercritical state, such as carbon dioxide (CO ₂ ).

Conventionally, as a supercritical refrigeration cycle apparatus, for example, as shown in Patent Document 1 (FIG. 5 in Patent Document 1), a compressor capable of increasing the pressure of the refrigerant to a pressure exceeding the critical pressure, and the compressor compressed by the compressor A radiator that cools the refrigerant, an expansion device that controls the refrigerant pressure on the radiator outlet side to a predetermined pressure that is determined based on the refrigerant temperature on the radiator outlet side, and a decompressor that is disposed in parallel and decompressed by the expansion device The first and second evaporators that evaporate the refrigerant are connected in a ring to form a cycle, and in the middle of the cycle, a high-pressure refrigerant that is led from the radiator to the expansion device, and a low-pressure that is led from the evaporator to the compressor A device provided with an internal heat exchanger for exchanging heat with a refrigerant is known.
JP-A-2005-106318

  However, the supercritical refrigeration cycle apparatus as described above has the following problems.

  In the case of having a plurality of evaporators, the flow rate of the refrigerant varies greatly depending on the number of evaporators through which the refrigerant flows, so that the heat exchange amount in the internal heat exchanger and the discharge temperature after discharge of the compressor change.

  For example, if the high pressure is the same, when the refrigerant is flowing through one evaporator, the amount of refrigerant evaporated in the evaporator is small compared to when the refrigerant is flowing through multiple evaporators. The suction pressure of the machine is low and the refrigerant flow rate is low. For this reason, the temperature difference between the outlet refrigerant temperature of the radiator (= high-pressure inlet refrigerant temperature of the internal heat exchanger) and the low-pressure inlet refrigerant temperature of the internal heat exchanger is large, and the refrigerant flow rate is small. The degree of superheat of the refrigerant sucked into the compressor by the internal heat exchanger increases, and the discharge temperature after discharge from the compressor also increases.

  Conversely, when the refrigerant is flowing through a plurality of evaporators, the amount of refrigerant evaporated in the evaporators increases, the suction pressure of the compressor increases, and the refrigerant flow rate increases. For this reason, the temperature difference between the outlet refrigerant temperature of the radiator (= high-pressure inlet refrigerant temperature of the internal heat exchanger) and the low-pressure inlet refrigerant temperature of the internal heat exchanger is small, and the refrigerant flow rate is also large. The degree of superheat of the refrigerant sucked by the compressor becomes small, and the discharge temperature after discharge from the compressor becomes low.

  In the supercritical refrigeration cycle apparatus, the coefficient of performance (COP) is improved when the superheat degree of the refrigerant sucked into the compressor is increased by increasing the performance (heat exchange amount) of the internal heat exchanger, but the refrigerant discharge temperature is It must be below the allowable temperature of high-pressure parts. The performance of the internal heat exchanger must be determined based on the condition that the discharge temperature is the highest so that the discharge temperature does not exceed the allowable temperature, and the refrigerant is flowing through one evaporator. When flowing, the degree of superheat of the refrigerant sucked in the compressor becomes small as described above, and the discharge temperature becomes low. For this reason, it will drive | operate in the state where COP is low compared with the case where it operates by the allowable upper limit temperature of discharge temperature.

  In view of the above problems, an object of the present invention is to provide a supercritical refrigeration cycle apparatus that can prevent a decrease in coefficient of performance (COP) even when the operating state of an evaporator changes.

  In order to achieve the above object, the present invention employs the following technical means.

  According to the first aspect of the present invention, in the vapor compression supercritical refrigeration cycle apparatus in which the high pressure in the refrigeration cycle is equal to or higher than the critical pressure of the refrigerant, the compressor (110) that sucks and compresses the refrigerant, and the compressor A radiator (120) that radiates the refrigerant discharged from (110), a plurality of high-pressure side branch channels (121, 122) that branch on the refrigerant downstream side of the radiator (120), and a plurality of high-pressure side branches A plurality of decompressors (131, 132) for decompressing the refrigerant flowing through the flow paths (121, 122), respectively, and a refrigerant flowing out from the plurality of decompressors (131, 132) are evaporated to compress (110) side. Among the plurality of evaporators (141, 142) that flow out to the bottom and the plurality of high-pressure side branch channels (121, 122), a plurality of decompressors from the branch point (A) of the high-pressure side branch channel (121, 122) (131, 1 2) including a plurality of internal heat exchangers (171, 172) for exchanging heat between the high-pressure refrigerant flowing between each of up to 2) and the low-pressure refrigerant flowing out from the plurality of evaporators (141, 142). It is a feature.

  Accordingly, since the plurality of internal heat exchangers (171, 172) can be operated so as to correspond to each of the plurality of evaporators (141, 142), the plurality of evaporators (141, 142) can be operated. 142), regardless of the operation state (the number of evaporators (141, 142) in which the refrigerant is flowing), the refrigerant sucked into the compressor (110) can always have a stable degree of superheat, and the refrigeration cycle The coefficient of performance (COP) can be prevented from decreasing.

  In the first aspect of the present invention, as in the second aspect of the present invention, a gas-liquid separator that collects the refrigerants flowing out from the plurality of evaporators (141, 142) and separates them into a gas-liquid separator ( 150) and a plurality of low-pressure side branch flow paths (161, 162) branched at the refrigerant downstream side of the gas-liquid separator (150) and joined again to the compressor (110) to provide a plurality of internal heat The low-pressure refrigerant that exchanges heat with the exchangers (171, 172) can be refrigerants that respectively flow through the plurality of low-pressure side branch channels (161, 162).

  Further, in the first aspect of the invention, as in the third aspect of the invention, the low pressures that collect the refrigerants respectively flowing out from the plurality of evaporators (141, 142) and flow into the compressor (110). It is good also as a refrigerant | coolant which provides a side aggregate flow path (163) and flows through a low pressure side collective flow path (163) sequentially as a low pressure refrigerant | coolant heat-exchanged with a some internal heat exchanger (171,172).

  Further, in the first aspect of the invention, as in the fourth aspect of the invention, the low pressure that collects the refrigerants flowing out from the plurality of evaporators (141, 142) and flows into the compressor (110). A side collective channel (163) is provided, and the plurality of internal heat exchangers (171, 172) are a plurality of high-pressure channels (171a, 172a) through which high-pressure refrigerant flows, and one low-pressure channel through which low-pressure refrigerant flows. (171b) may be integrally provided so that the refrigerant flowing through the low-pressure channel (163) flows through the low-pressure channel (171b).

  And, the internal heat exchanger (171, 172) according to claim 4 has a plurality of high-pressure channels (171a, 171b) around one low-pressure channel (171b) as in the invention according to claim 5. 172a) or a plurality of high-pressure channels (171a, 172a) arranged side by side in one low-pressure channel (171b).

  Further, in the invention according to claim 6, in the vapor compression supercritical refrigeration cycle apparatus in which the high pressure in the refrigeration cycle is equal to or higher than the critical pressure of the refrigerant, a compressor (110) that sucks and compresses the refrigerant; A radiator (120) that radiates the refrigerant discharged from the compressor (110), a decompressor (131) that decompresses the refrigerant that flows out of the radiator (120), and a refrigerant downstream side of the decompressor (131) And a plurality of evaporators that evaporate the refrigerant flowing through the plurality of low-pressure side branch flow paths (121b, 122b) and the plurality of low-pressure side branch flow paths (121b, 122b) and flow out to the compressor (110) side. (141, 142) and a plurality of high-pressure refrigerants flowing between the radiator (120) and the decompressor (131) and a plurality of low-pressure refrigerants flowing out from the plurality of evaporators (141, 142). internal And a plurality of internal heat exchangers (171, 172), a plurality of low-pressure channels (171b, 172b) through which the low-pressure refrigerant flows, and a single high-pressure flow through which the high-pressure refrigerant flows. The road (171a) is integrally provided.

  Thereby, with respect to the invention described in claim 4, the number of decompressors (131) used is reduced, and the setting of the plurality of high-pressure side branch channels (121, 122) is unnecessary, and a plurality of evaporations are performed. Regardless of the operation state of the compressors (141, 142) (the number of evaporators (141, 142) in which the refrigerant is flowing), the refrigerant sucked into the compressor (110) can always have a stable degree of superheat. It is possible to prevent the coefficient of performance (COP) of the refrigeration cycle from being lowered.

  The internal heat exchangers (171, 172) in the invention described in claim 6 are, as in the invention described in claim 7, a plurality of low-pressure channels (171b, 171b) around one high-pressure channel (171a). 172b) or a plurality of low-pressure channels (171b, 172b) arranged in one high-pressure channel (171a).

  In the invention described in claim 1, as in the invention described in claim 8, the refrigerants flowing out from the plurality of evaporators (141, 142) are combined on the compressor (110) side, respectively. The high-pressure refrigerant and low-pressure refrigerant in each of the plurality of internal heat exchangers (171, 172) can be formed so that the high-pressure refrigerant and low-pressure refrigerant in each of the plurality of evaporators (141, 142) correspond to each other.

  In the invention according to claim 9, the gas-liquid separator (150) for separating the gas-liquid of the refrigerant to the downstream side of the refrigerant of at least one of the evaporators (141, 142). Is featured.

  Thereby, since the outflow of the liquid-phase refrigerant with respect to a compressor (110) can be eliminated, the liquid compression in a compressor (110) can be prevented reliably.

  In the invention described in claim 10, the degree of superheat of the low-pressure refrigerant after heat exchange of the internal heat exchangers (171, 172) is controlled to be a predetermined value by the pressure reducer (132). It is a feature.

  Thereby, since the superheat degree in the refrigerant | coolant exit part of an evaporator (141, 142) can be made small, while being able to improve the cooling performance in an evaporator (141, 142), distribution of blowing temperature is reduced. be able to. Further, since the superheat degree of the refrigerant sucked into the compressor (110) can be directly controlled, it is possible to reduce the variation in the coefficient of performance (COP) due to the difference in the operation state of the plurality of evaporators (141, 142). it can.

  According to the tenth aspect of the present invention, the decompressor (132) adjusts the valve opening degree according to the degree of superheat of the low-pressure refrigerant after the heat exchange, as in the case of the eleventh aspect. A mechanical control valve (132).

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIG. A supercritical refrigeration cycle apparatus (hereinafter referred to as a refrigeration cycle apparatus) 100 according to the present embodiment is a vapor compression refrigeration cycle apparatus including a plurality of evaporators 141 and 142, and a dual type used for an automobile or the like as an example. What is applied to the vehicle air conditioner will be described. Further, in the refrigeration cycle apparatus 100, carbon dioxide (CO ₂ ) is used as the refrigerant, and a supercritical refrigeration cycle in which the high pressure is equal to or higher than the critical pressure is achieved.

  As shown in FIG. 1, the refrigeration cycle apparatus 100 is configured by sequentially connecting a compressor 110, a radiator 120, expansion valves 131 and 132, evaporators 141 and 142, an accumulator 150, internal heat exchangers 171 and 172, and the like. Has been.

  The compressor 110 is a fluid machine that sucks and compresses refrigerant and discharges the refrigerant as a high-temperature and high-pressure refrigerant to the radiator 120 described later, and its operation is controlled by a control device (ECU) (not shown). The refrigerant is compressed by the compressor 110 so as to be equal to or higher than the critical pressure. The compressor 110 may be a variable displacement type that adjusts the discharge amount so that the discharge capacity per rotation can be changed, or the discharge capacity per rotation is fixed to a predetermined value, but the ON-OFF operation A fixed displacement type that adjusts the discharge amount according to the operation ratio is used.

  The radiator 120 is a high-pressure side heat exchanger that radiates heat of the high-temperature and high-pressure refrigerant discharged from the compressor 110. The radiator 120 is provided with a blower fan 120a, and the radiator 120 is between the high-temperature and high-pressure refrigerant discharged from the compressor 110 and the air blown by the blower 120a (or running wind when the vehicle is running). Heat is exchanged in order to cool the refrigerant. The blower fan 120a can be configured by, for example, an electric fan driven by a motor, an engine fan driven by an engine, a hydraulic motor fan driven by a hydraulic motor, or the like.

  On the downstream side of the refrigerant of the radiator 120, two flow paths are formed with a first high-pressure side branch flow path 121 and a second high-pressure side branch flow path 122 with A as a branch point. A high-pressure control expansion valve 131 and a superheat expansion valve 132 are provided in the middle of the high-pressure side branch flow paths 121 and 122.

  The high-pressure control expansion valve 131 constitutes a first pressure reducer. Here, the refrigerant temperature at the outlet side of the radiator 120 is detected by the temperature sensing unit, and the coefficient of performance (hereinafter, COP) of the refrigeration cycle is optimal (maximum). ), And a mechanical expansion valve that decompresses and expands the refrigerant toward the first evaporator 141 described later. The high-pressure control expansion valve 131 may be an electric expansion valve that is electrically controlled by the ECU in addition to the mechanical type described above.

  The superheat control valve 132 constitutes a second pressure reducer. Here, the outlet side refrigerant temperature of the second evaporator 142 and the refrigerant pressure in the second evaporator 142 are detected to detect the second evaporator. 142 is a mechanical expansion valve (mechanical control valve) that controls the degree of superheat (superheat amount) of the outlet side refrigerant at a predetermined degree of superheat. The superheat control valve 132 has a relationship of being arranged in parallel with the high-pressure control expansion valve 131 in the refrigeration cycle.

  In the second high-pressure side branch flow path 122, an electromagnetic valve 122 a that is controlled to be opened and closed by the ECU is provided on the refrigerant upstream side of the superheat control valve 132. The electromagnetic valve 122a opens and closes to block the case where the refrigerant that has flowed out of the radiator 120 and has flowed through the second high-pressure side branch flow path 122 is allowed to flow into the second evaporator 142 side. It is a valve that can switch between cases.

  The first evaporator 141 is a first low-pressure side heat exchanger that evaporates the liquid refrigerant decompressed and expanded by the high-pressure side control expansion valve 131, and the first evaporator 141 of the high-pressure side control expansion valve 131 of the first high-pressure side branch flow path 121. It is connected to the refrigerant downstream side. The first evaporator 141 absorbs heat from the blown air blown by the first blower 141a and evaporates the liquid refrigerant. The blown air is cooled while deprived of heat from the refrigerant and dehumidified, and is sent as air-conditioning air from the front side of the passenger compartment toward the passenger in the front seat.

  The second evaporator 142 is a second low-pressure side heat exchanger that evaporates the liquid refrigerant decompressed and expanded by the superheat expansion valve 132 with a predetermined superheat degree on the outflow side. The superheat expansion valve 132 is connected to the refrigerant downstream side. The second evaporator 142 absorbs heat from the blown air blown by the second blower 141a and evaporates the liquid refrigerant. The blown air is cooled while deprived of heat from the refrigerant and dehumidified, and is blown as a cooling wind from the rear side of the passenger compartment toward the passenger in the rear seat.

  The refrigerant flowing out from the first evaporator 141 and the second evaporator 142 is merged (collected) and flows into the accumulator 150. The accumulator 150 is a gas-liquid separator that accumulates surplus refrigerant in the refrigeration cycle and separates the refrigerant flowing in from both the evaporators 141 and 142 into a liquid phase refrigerant and a gas phase refrigerant. The accumulator 150 is disposed between the refrigerant downstream sides of the evaporators 141 and 142 and first and second internal heat exchangers 171 and 172 described later.

  Two flows of the first low-pressure side branch flow path 161 and the second low-pressure side branch flow path 162 that are branched once at the refrigerant downstream of the accumulator 150 and are joined again and connected to the suction side of the compressor 110. A road is formed.

  A first internal heat exchanger 171 is provided between the first high pressure side branch flow path 121 and the first low pressure side branch flow path 161, and the second high pressure side branch flow path 122 and the second low pressure side branch flow path 161 are provided. A second internal heat exchanger 172 is provided between the flow path 162.

  The first internal heat exchanger 171 is a heat exchanger that exchanges heat between the high-pressure refrigerant that flows through the first high-pressure side branch flow path 121 and the low-pressure refrigerant that flows through the first low-pressure side branch flow path 161. The first internal heat exchanger 171 includes two channels, a high-pressure channel 171a through which a high-pressure refrigerant flows and a low-pressure channel 171b through which a low-pressure refrigerant flows, and is disposed so that both the channels 171a and 172b are close to each other. It is formed as a heat exchanger.

  Similarly to the first internal heat exchanger 171, the second internal heat exchanger 172 has a high-pressure refrigerant flowing through the second high-pressure side branch flow path 122 and a low-pressure flowing through the second low-pressure side branch flow path 162. It is a heat exchanger that exchanges heat with a refrigerant. The second internal heat exchanger 172 includes two flow paths, a high-pressure flow path 172a through which high-pressure refrigerant flows and a low-pressure flow path 172b through which low-pressure refrigerant flows, and is disposed so that both flow paths 172a and 172b are close to each other. It is formed as a heat exchanger.

  Next, the operation of the refrigeration cycle apparatus 100 based on the above configuration will be described.

  First, when both the first and second evaporators 141 and 142 are operated, the electromagnetic valve 122a is opened by an ECU (not shown).

  The refrigerant is compressed to a high temperature and a high pressure by the operation of the compressor 110 and discharged to the radiator 120. The radiator 120 cools the refrigerant by the air blown by the blower fan 120a. The refrigerant flowing out of the radiator 120 flows into the first high pressure side branch flow path 121 and the second high pressure side branch flow path 122 at the branch point A. The high-pressure refrigerant flowing through the first high-pressure side branch channel 121 passes through the high-pressure channel 171a of the first internal heat exchanger 171 and is decompressed and expanded while maintaining the high pressure at a predetermined pressure by the high-pressure control expansion valve 131. It reaches the first evaporator 141.

  The high-pressure refrigerant flowing from the branch point A through the second high-pressure side branch flow path 122 is decompressed and expanded by the superheat expansion valve 132 via the high-pressure flow path 172a and the electromagnetic valve 122a of the second internal heat exchanger 172. It reaches the second evaporator 142.

  Each evaporator 141, 142 absorbs heat from the blown air from the first and second blowers 141a, 142a, evaporates the low-pressure refrigerant, and cools the blown air with latent heat of vaporization at that time. In the second evaporator 142, the superheat expansion valve 132 maintains the degree of superheat of the outlet side refrigerant at a predetermined degree of superheat.

  The low-pressure refrigerant that has flowed out of each of the evaporators 141 and 142 is gas-liquid separated by the accumulator 150, and the gas-phase refrigerant is discharged to flow through the first low-pressure side branching channel 161 and the second low-pressure side branching channel 162. Flowing.

  In the first internal heat exchanger 171, the high-pressure refrigerant flowing from the first high-pressure side branch flow path 121 to the high-pressure flow path 171a and the low-pressure refrigerant flowing from the first low-pressure side branch flow path 161 to the low-pressure flow path 171b flow. . The high-pressure refrigerant is cooled (supercooled) by the low-pressure refrigerant, and the low-pressure refrigerant is superheated by the high-pressure refrigerant. The cooled high-pressure refrigerant reaches the high-pressure control expansion valve 131, and the overheated low-pressure refrigerant is sucked into the compressor 110.

  In the second internal heat exchanger 172, high-pressure refrigerant that flows from the second high-pressure side branch flow path 122 to the high-pressure flow path 172a, and low-pressure refrigerant that flows from the second low-pressure side branch flow path 162 to the low-pressure flow path 172b Flows. The high-pressure refrigerant is cooled (supercooled) by the low-pressure refrigerant, and the low-pressure refrigerant is superheated by the high-pressure refrigerant. Then, the cooled high-pressure refrigerant reaches the superheat expansion valve 132 through the electromagnetic valve 122a, and the overheated low-pressure refrigerant is sucked into the compressor 110.

  Next, when the first evaporator 141 is operated and the second evaporator 142 is not operated, the electromagnetic valve 122a is closed by an ECU (not shown). At this time, the refrigerant flowing out of the radiator 120 and flowing into the second high-pressure side branch flow path 122 is stopped by the electromagnetic valve 122a, and the high-pressure flow path 172a of the second internal heat exchanger 172 and the second evaporator. The refrigerant flow at 142 is blocked.

  Therefore, the refrigerant that has flowed out of the radiator 120 flows through the first high-pressure side branch flow path 121, is evaporated by the first evaporator 141, passes through the accumulator 150, and passes through the first and second low-pressure side branch flow paths 161. , 162 and return to the compressor 110. That is, the 1st internal heat exchanger 171 and the 1st evaporator 141 will be in an operation state, and the 2nd evaporator 142 will be in a non-operating state.

  As described above, in the present embodiment, the high-pressure branch channels 121 and 122 and the low-pressure branch channels 161 and 162 are provided so as to correspond to the two evaporators 141 and 142, and the branch channels 121 are provided. , 122, 161, 162 are provided with two internal heat exchangers 171, 172 that perform heat exchange between refrigerants. As a result, the two internal heat exchangers 171 and 172 can be operated so as to correspond to the two evaporators 141 and 142, respectively. Therefore, the operating state of the two evaporators 141 and 142 (the refrigerant is flowing). Regardless of the number of evaporators 141 and 142, it is possible to always give a stable degree of superheat to the refrigerant sucked in the compressor 110, and to prevent the COP of the refrigeration cycle from being lowered.

(Second Embodiment)
A second embodiment of the present invention is shown in FIG. In the second embodiment, the high-pressure side control expansion valve 131 serving as the first pressure reducer and the superheat expansion valve 132 serving as the second pressure reducer are respectively set to a predetermined opening with respect to the first embodiment. Orifices (fixed restrictors) 131a and 132a are changed.

  In addition, the first and second low-pressure side branch channels 161 and 162 are formed as one low-pressure side collective channel 163, and the low-pressure channels 171b and 172b of the internal heat exchangers 171 and 172 are the low-pressure side collective flow. In line 163, the refrigerant flows in the order of accumulator 150 → second internal heat exchanger 172 → first internal heat exchanger 171 → compressor 110 so as to be connected in series between accumulator 150 and compressor 110. It is configured.

  As a result, the first and second pressure reducers can be simplified, and the branching section and the joining section of the low-pressure side collecting flow path 163 can be reduced. Therefore, it is possible to cope with the low cost.

  In addition, it is good also as what changed only the superheat expansion valve 132 side into the orifice 132a with respect to 1st Embodiment.

(Third embodiment)
A third embodiment of the present invention is shown in FIGS. The third embodiment integrates the two internal heat exchangers 171 and 172 with respect to the first embodiment by using a box type high pressure control valve 131b as a first pressure reducer and changing the refrigerant flow path. The internal heat exchanger 171A is formed.

  The Box-type high-pressure control valve 131b is formed integrally with a temperature sensing part 131c and a valve body part 131d, and the high-temperature and high-pressure refrigerant flowing out from the radiator 120 first passes through the temperature sensing part 131c and will be described later. The valve body 131d is circulated again after flowing through the internal heat exchanger 171A (high-pressure channel 171a). The temperature sensing part 131c of the Box type high pressure control valve 131b is provided on the refrigerant downstream side of the branch point A of both the high pressure side branch flow paths 121 and 122.

  The temperature sensing part 131c includes two pressure chambers sandwiching the diaphragm, and the diaphragm is displaced by a pressure balance between the two pressure chambers generated according to the refrigerant temperature. The valve body 131 is connected to the diaphragm, and the valve opening degree is changed by being displaced according to the displacement of the diaphragm.

  The refrigerant flow path as the refrigeration cycle is changed as follows. That is, the refrigerant downstream side of the first evaporator 141 is connected to the accumulator 150. In addition, the refrigerant downstream side of the second evaporator 142 is joined with the outflow side of the accumulator 150 so as to be connected to the compressor 110 as one low pressure collecting channel 163 hereinafter.

  As shown in FIGS. 4 and 5, the internal heat exchanger 171A includes an inner tube 173 and an outer tube 174, and a double tube in which both tubes 173 and 174 are connected by a plurality of ribs 175 arranged in the circumferential direction. It is formed on the base. A partition portion 176 that partitions the longitudinal direction of the outer tube 174 is formed at the center of the double tube. Therefore, the inner pipe 173, the outer pipe 174, and the partition portion 176 form three internal spaces in the internal heat exchanger 171A. One is a space formed inside the inner pipe 173, which is used as a low-pressure channel 171b. The second and third are spaces formed between the inner tube 173 and the outer tube 174 with the partition portion 176 as a boundary in the longitudinal direction of the inner tube 173, and one (right side in FIG. 4) is formed. A high pressure channel 171a is provided, and the other (left side in FIG. 4) is a high pressure channel 172a. That is, the internal heat exchanger 171A is formed such that a plurality of high-pressure channels 171a and 172a are arranged in the longitudinal direction of one low-pressure channel 171b.

  And the high-pressure inflow part 177a and the high-pressure outflow part 177b which are each connected to this high-pressure channel 171a are formed in the both-ends side of the longitudinal direction of the high-pressure channel 171a. Similarly, a high-pressure inflow portion 178a and a high-pressure outflow portion 178b that respectively communicate with the high-pressure channel 172a are formed on both ends in the longitudinal direction of the high-pressure channel 172a. Furthermore, a low pressure inflow portion 179a and a low pressure outflow portion 179b that respectively communicate with the internal flow channel 171b are formed on both ends in the longitudinal direction of the low pressure flow channel 171b.

  The high pressure inflow portion 177a is connected to the radiator 120 (the temperature sensing portion 131c side of the Box type high pressure control valve 131b), and the high pressure outflow portion 177b is the first evaporator 141 (the valve body portion 131d side of the Box type high pressure control valve 131b). It is connected to the. The high pressure inflow portion 178a is connected to the radiator 120, and the high pressure outflow portion 178b is connected to the superheat expansion valve 132 (on the second evaporator 142 side). Further, the low pressure inflow portion 179 a is connected to the accumulator 150, and the low pressure outflow portion 179 b is connected to the compressor 110.

  In the present embodiment, when both the first and second evaporators 141 and 142 are operated (when the electromagnetic valve 122a is opened), the internal heat exchanger 171A has the first high-pressure side branch channel 121 to the high-pressure channel 171a. The high-pressure refrigerant flows into the high-pressure flow path 172a from the second high-pressure side branch flow path 122. Further, the low-pressure refrigerant flows from the low-pressure side collecting channel 163 into the low-pressure channel 171b. Then, heat exchange is performed between the high-pressure refrigerant in the high-pressure channel 171a and the high-pressure channel 172a and the low-pressure refrigerant in the low-pressure channel 171b. That is, the internal heat exchanger 171A functions as two independent heat exchangers corresponding to the high-pressure channels 171a and 172a. The high-pressure refrigerant is cooled (supercooled) by the low-pressure refrigerant, and the low-pressure refrigerant is superheated by the high-pressure refrigerant. The cooled high-pressure refrigerant reaches the Box type high-pressure control valve 131b and the superheat expansion valve 132, and the overheated low-pressure refrigerant is sucked into the compressor 110.

  Next, when the first evaporator 141 is operated and the second evaporator 142 is not operated, the high-pressure refrigerant flows from the first high-pressure side branch channel 121 to the high-pressure channel 171a in the internal heat exchanger 171A. . Further, the refrigerant that has passed through the first evaporator 141 flows from the low-pressure side collective flow path 163 into the low-pressure flow path 171b. Then, heat exchange is performed between the high-pressure refrigerant in the high-pressure channel 171a and the low-pressure refrigerant in the low-pressure channel 171b. The high-pressure refrigerant is cooled (supercooled) by the low-pressure refrigerant, and the low-pressure refrigerant is superheated by the high-pressure refrigerant. The cooled high-pressure refrigerant reaches the Box type high-pressure control valve 131b, and the overheated low-pressure refrigerant is sucked into the compressor 110.

  Similarly to the first embodiment, this embodiment can also exchange heat with the internal heat exchanger 171A so as to correspond to each of the two evaporators 141 and 142. Therefore, the operating state of the two evaporators 141 and 142 Regardless of (the number of evaporators 141 and 142 in which refrigerant is flowing), it is possible to always give a stable degree of superheat to the refrigerant sucked in the compressor 110, and the COP of the refrigeration cycle is reduced. Can be prevented.

  Further, it is not necessary to branch the refrigerant flow path downstream of the evaporators 141 and 142 with respect to the first embodiment (the low pressure side branch flow paths 161 and 162 are abolished as the low pressure side collective flow path 163). Formation), the branching section, and the joining section can be abolished to make a simple refrigerant pipe.

  In addition, along with the formation of the low-pressure side collective flow path 163, the internal heat exchanger 171A can be integrally configured, and the simplification and mountability of the internal heat exchanger can be improved.

  Further, a Box-type high pressure control valve 131b is used as the first pressure reducer, and a simple configuration can be achieved with respect to the high pressure control expansion valve 131.

  The temperature sensing part 131c of the Box type high pressure control valve 131 is provided on the refrigerant downstream side of the branch point A of the high pressure side branch passages 121 and 122, but is provided on the refrigerant upstream side of the branch point A. May be.

(Fourth embodiment)
A fourth embodiment of the present invention is shown in FIGS. 4th Embodiment changes the structure of internal heat exchanger 171A with respect to the said 3rd Embodiment, and is set as internal heat exchanger 171B.

  The internal heat exchanger 171B is formed by stacking three tubes having a flat cross section. The inside of the tube is partitioned into a plurality of spaces by, for example, extrusion molding, and is joined so that the long side surfaces with a flat cross section are in contact with each other. Of the three tubes, the middle tube forms a low-pressure channel 171b, and the two outer tubes form high-pressure channels 171a and 172a, respectively. That is, the periphery of one low-pressure channel 171b is formed so as to be surrounded by two high-pressure channels 171a and 172a (so as to be sandwiched here).

  A joint is joined to an end portion side in the longitudinal direction of each tube to form an inflow portion and an outflow portion with respect to the inside of the tube. Specifically, a first high-pressure inflow portion 177a is formed on one end side of the high-pressure channel 171a, and a first high-pressure outflow portion 177b is formed on the other end side. In addition, a second high-pressure inflow portion 178a is formed on one end side of the high-pressure channel 172a, and a second high-pressure outflow portion 178b is formed on the other end side. Furthermore, a low-pressure outflow portion 179b is formed on one end side of the low-pressure channel 171b, and a low-pressure inflow portion 179a is formed on the other end side. The other side of each inflow portion 177a, 178a, 179a and each outflow portion 177b, 178b, 179b is the same as that in the third embodiment.

  The operation of the refrigeration cycle apparatus 100 of the fourth embodiment is the same as that of the third embodiment, whereby the same effect as that of the third embodiment can be obtained.

(Fifth embodiment)
A fifth embodiment of the present invention is shown in FIG. The fifth embodiment is different from the third embodiment in that the refrigerant flow path is changed and an internal heat exchanger 171B is adopted instead of the internal heat exchanger 171A.

  The refrigerant flow path as the refrigeration cycle is changed as follows. That is, the refrigerant downstream side of the radiator 120 is replaced with the first and second high-pressure side branch channels 121 and 122 as one high-pressure refrigerant channel 123, and the high-pressure controlled expansion is performed on the refrigerant downstream side of the high-pressure refrigerant channel 123. A valve 131 is provided. The refrigerant downstream side of the high-pressure control expansion valve 131 in the high-pressure refrigerant flow path 123 is connected to one flow path opening of the three-way flow rate adjustment valve 124. Further, the remaining two flow path ports of the three-way flow control valve 124 are connected to the first low pressure side branch flow path 121b and the second low pressure side branch flow path 122b, respectively. The first and second low-pressure side branch flow paths 121b and 122b are merged on the refrigerant downstream side (between the internal heat exchanger 171B and the compressor 110) to form a low-pressure side collective flow path 163. The refrigerant downstream side of the flow path 163 is connected to the refrigerant suction side of the compressor 110.

  The three-way flow rate adjustment valve 124 is a valve whose valve opening degree is adjusted with respect to the first and second low-pressure side branch passages 121b and 122b by an ECU (not shown). The amount of refrigerant flowing from the passage 123 to the low-pressure side branch passages 121b and 122b is adjusted (distributed).

  A first evaporator 141 and an accumulator 150 are sequentially arranged in the first low pressure side branch flow path 121b, and a second evaporator 142 is arranged in the second low pressure side branch flow path 122b. Yes.

  The internal heat exchanger 171B is a heat exchanger including one high-pressure channel 171a and two low-pressure channels 171b and 172b, and two low-pressure channels so as to sandwich (enclose) the high-pressure channel 171a. 171b and 172b are disposed and integrally formed.

  The refrigerant flowing through the high-pressure refrigerant channel 123 flows from the radiator 120 to the high-pressure control expansion valve 131 through the high-pressure channel 171a, and flows out from the first evaporator 141 → accumulator 150 into the low-pressure channel 171b. The refrigerant flowing through the low pressure side branch flow path 121b flows, and the refrigerant flowing out of the second evaporator 142 and flowing through the second low pressure side branch flow path 122b flows through the low pressure flow path 172b.

  In the present embodiment, when both the first and second evaporators 141 and 142 are operated, the valve opening degree of the three-way flow rate adjustment valve 124 is adjusted so that both the first and second evaporators 141 and 142 are opened. In addition, the ratio of both valve openings is set to a predetermined value. The high-temperature and high-pressure refrigerant discharged from the compressor 110 reaches the radiator 120 → the high-pressure refrigerant flow path 123 → the high-pressure control expansion valve 131 → the three-way flow rate adjustment valve 124. The refrigerant is distributed by the three-way flow control valve 124, one flows through the first evaporator 141 → accumulator 150 (first low-pressure side branch flow path 121b), and the other flows through the second evaporator 142 (second low-pressure side branch flow path). 122 b), merged in the low-pressure side collecting flow path 163, and sucked into the compressor 110.

  In the internal heat exchanger 171B, the high-pressure refrigerant flows from the high-pressure refrigerant channel 123 into the high-pressure channel 171a. Further, the low-pressure refrigerant flows into the low-pressure channel 171b from the first low-pressure side branch channel 121b on the downstream side of the accumulator 150 (first evaporator 141). Further, the low pressure refrigerant flows from the second low pressure side branch flow path 122b downstream of the second evaporator 142 into the low pressure flow path 172b. Then, heat exchange is performed between the high-pressure refrigerant in the high-pressure channel 171a and the low-pressure refrigerant in the low-pressure channels 171b and 172b. That is, the internal heat exchanger 171B functions as two independent heat exchangers corresponding to the low pressure channels 171b and 172b. The high-pressure refrigerant is cooled (supercooled) by the low-pressure refrigerant, and the low-pressure refrigerant is superheated by the high-pressure refrigerant. The cooled high-pressure refrigerant reaches the high-pressure control expansion valve 131, and the overheated low-pressure refrigerant is sucked into the compressor 110.

  Next, when the first evaporator 141 is operated and the second evaporator 142 is not operated, the valve opening degree of the three-way flow rate adjustment valve 124 is adjusted, the second evaporator 142 side is closed, and the first evaporator 142 is closed. It is set so that the evaporator 141 side has a predetermined valve opening. That is, the refrigerant flow to the second low-pressure side branch flow path 122b and the second evaporator 142 is blocked.

  The high-temperature and high-pressure refrigerant discharged from the compressor 110 is the radiator 120 → the high-pressure refrigerant flow path 123 → the high-pressure control expansion valve 131 → the three-way flow control valve 124 → the first evaporator 141 → the accumulator 150 (first low-pressure side branch flow) Channel 121 b) → flows through the low-pressure side collecting channel 163 and is sucked into the compressor 110.

  In the internal heat exchanger 171B, the high-pressure refrigerant flows from the high-pressure refrigerant channel 123 into the high-pressure channel 171a. Further, the low-pressure refrigerant flows into the low-pressure channel 171b from the first low-pressure side branch channel 121b on the downstream side of the accumulator 150 (first evaporator 141). Then, heat exchange is performed between the high-pressure refrigerant in the high-pressure channel 171a and the low-pressure refrigerant in the low-pressure channel 171b. The high-pressure refrigerant is cooled (supercooled) by the low-pressure refrigerant, and the low-pressure refrigerant is superheated by the high-pressure refrigerant. The cooled high-pressure refrigerant reaches the high-pressure control expansion valve 131, and the overheated low-pressure refrigerant is sucked into the compressor 110.

  As a result, as in the third embodiment, heat exchange can be performed in the internal heat exchanger 171B so as to correspond to the two evaporators 141 and 142, so that the operating states of the two evaporators 141 and 142 ( Regardless of the number of evaporators 141 and 142 that are flowing refrigerant), the refrigerant sucked into the compressor 110 can always have a stable degree of superheat, and the COP of the refrigeration cycle is prevented from being lowered. can do.

  Further, compared to the third embodiment, the number of decompressors (131b, 132 → 131) can be reduced, and the setting of a plurality of high-pressure side branch channels (121, 122) is not required, and the number of branch portions is reduced. Thus, a low-cost system can be obtained.

(Sixth embodiment)
A sixth embodiment of the present invention is shown in FIG. The sixth embodiment employs a Box-type high pressure control valve 131b (same as the third embodiment) as a first pressure reducer and an orifice 132a as a second pressure reducer, compared to the first embodiment. The internal heat exchangers 171 and 172 are formed by changing the flow path on the refrigerant downstream side of the evaporators 141 and 142.

  The flow paths on the refrigerant downstream side of the evaporators 141 and 142 respectively extend in parallel toward the compressor 110, and are joined and connected before the compressor 110. And between the refrigerant | coolant downstream side of the 1st evaporator 141, and the compressor 110, the accumulator 150 and the 1st internal heat exchanger 171 are arrange | positioned in order. Further, a second internal heat exchanger 172 is disposed between the refrigerant downstream side of the second evaporator 142 and the compressor 110.

  In the present embodiment, when the refrigeration cycle apparatus 100 is operated, heat is exchanged in the first internal heat exchanger 171 by the refrigerant flowing into the first evaporator 141 and the refrigerant flowing out of the first evaporator 141. . Further, heat exchange is performed in the second internal heat exchanger 172 by the refrigerant flowing into the second evaporator 142 and the refrigerant flowing out of the second evaporator 142.

  Therefore, the two internal heat exchangers 171 and 172 can be operated to completely correspond to each of the evaporators 141 and 142, that is, each of the evaporators 141 and 142 can be operated. Regardless of the operating state (the number of evaporators 141 and 142 in which refrigerant is flowing), the refrigerant sucked in the compressor 110 can always have a stable degree of superheat, and the COP of the refrigeration cycle is reduced. Can be prevented.

  Further, since the refrigerant downstream flow path of the second evaporator 142 is directly connected to the compressor 110 without passing through the accumulator 150, the second internal heat exchanger 172 is disposed in the engine room of the vehicle. There is no need to do this, and it can be arranged under the floor of the vehicle or in the vicinity of the second evaporator 142 as shown in FIG. For this reason, it is not necessary to arrange | position the 2nd internal heat exchanger 172 in a narrow engine room, and mountability can be improved.

  Also, even if there is a refrigeration cycle unit for the rear seats depending on the vehicle, the related equipment for the rear seat unit can be mounted compactly in addition to the engine room, so the number of changes in the engine room can be reduced. This makes mounting design easy.

  The refrigerant downstream side of the second internal heat exchanger 172 may be connected between the accumulator 150 and the first internal heat exchanger 171.

(Seventh embodiment)
A seventh embodiment of the present invention is shown in FIG. The seventh embodiment adopts a high pressure control expansion valve 131 (same as the first embodiment) as the first pressure reducer instead of the Box type high pressure control valve 131b, and the second pressure reducer. The superheat expansion valve 132 (same as in the first embodiment) is used instead of the orifice 132a. The temperature sensing part of the superheat expansion valve 132 is arranged between the refrigerant downstream side of the second evaporator 142 and the second internal heat exchanger 172.

  In the present embodiment, the refrigerant amount can be appropriately adjusted even when the refrigerant amount fluctuation of the second evaporator 142 is large. In addition, since the degree of superheat on the downstream side of the refrigerant in the second evaporator 142 is stabilized, the variation in COP due to the operating state can be reduced.

(Eighth embodiment)
FIG. 12 shows an eighth embodiment of the present invention. In the eighth embodiment, the basic configuration is the same as that in the seventh embodiment, but the position of the temperature sensing unit in the decompressor is changed.

  That is, the temperature sensing part of the high-pressure control expansion valve 131 is disposed between the junction A and the first internal heat exchanger 171. Further, the temperature sensing part of the superheat expansion valve 132 is disposed on the refrigerant downstream side of the second internal heat exchanger 172. The electromagnetic valve 122 a is disposed on the refrigerant upstream side of the second internal heat exchanger 172 in the second high-pressure side branch flow path 122.

  Thereby, since the superheat degree in the refrigerant | coolant exit part of a 2nd evaporator can be made small, while the cooling performance in the 2nd evaporator 142 can be improved, distribution of blowing temperature can be reduced. Furthermore, since the degree of superheat of the refrigerant sucked into the compressor 110 (the outlet refrigerant of the second internal heat exchanger 172) can be directly controlled, the variation in COP due to the difference in the operating state of the plurality of evaporators 141 and 142 can be reduced. Can be small.

(Other embodiments)
In each of the above embodiments, a supercritical refrigeration cycle using carbon dioxide as a refrigerant has been described. In addition to carbon dioxide, for example, a refrigerant used in a supercritical region such as ethylene, ethane, or nitrogen oxide is used. Also good.

  Moreover, in each embodiment, although it is set as the structure provided with the two evaporators 141 and 142 and the two internal heat exchangers 171 and 172, it also exists in the refrigerating cycle apparatus provided with three or more evaporators and an internal heat exchanger, respectively. It may be applied. For example, in the case of an apparatus including three evaporators, a high-pressure control expansion valve that controls the flow rate of refrigerant flowing through one of the evaporators, and a superheat expansion valve that controls the flow rate of refrigerant flowing through the remaining two evaporators And a configuration including

  In addition, since the internal heat exchangers 171 and 172 can give the superheat degree to the refrigerant sucked into the compressor 110, the gas-liquid separator 150 in the refrigeration cycle may be abolished.

It is a schematic diagram which shows the structure of the supercritical refrigeration cycle apparatus in 1st Embodiment. It is a schematic diagram which shows the structure of the supercritical refrigeration cycle apparatus in 2nd Embodiment. It is a schematic diagram which shows the structure of the supercritical refrigeration cycle apparatus in 3rd Embodiment. It is sectional drawing which shows the internal heat exchanger in FIG. It is sectional drawing which shows the AA part in FIG. It is an external appearance perspective view which shows the internal heat exchanger in 4th Embodiment. It is sectional drawing which shows the BB part in FIG. It is a schematic diagram which shows the structure of the supercritical refrigeration cycle apparatus in 5th Embodiment. It is a schematic diagram which shows the structure of the supercritical refrigeration cycle apparatus in 6th Embodiment. It is a perspective view which shows the vehicle mounting state of the supercritical refrigeration cycle apparatus in FIG. It is a schematic diagram which shows the structure of the supercritical refrigeration cycle apparatus in 7th Embodiment. It is a schematic diagram which shows the structure of the supercritical refrigeration cycle apparatus in 8th Embodiment.

Explanation of symbols

100 Supercritical refrigeration cycle apparatus 110 Compressor 120 Radiator 121 First high-pressure side branch flow path (high-pressure side branch flow path)
121b First low pressure side branch flow path (low pressure side branch flow path)
122 2nd high pressure side branch flow path (high pressure side branch flow path)
122b Second low pressure side branch flow path (low pressure side branch flow path)
131 High-pressure control expansion valve (first pressure reducer)
132 Superheat expansion valve (second pressure reducer, mechanical control valve)
141 First evaporator (evaporator)
142 Second evaporator (evaporator)
150 Accumulator (gas-liquid separator)
161 First low pressure side branch flow path (low pressure side branch flow path)
162 Second low pressure side branch flow path (low pressure side branch flow path)
163 Low pressure side collective flow path 171 First internal heat exchanger (internal heat exchanger)
171a High pressure flow path 171b, 172b Low pressure flow path 172 Second internal heat exchanger (internal heat exchanger)

Claims (11)

A vapor compression supercritical refrigeration cycle apparatus in which the high pressure in the refrigeration cycle is equal to or higher than the critical pressure of the refrigerant,
A compressor (110) for sucking and compressing the refrigerant;
A radiator (120) for radiating the refrigerant discharged from the compressor (110);
A plurality of high-pressure side branch channels (121, 122) branching on the refrigerant downstream side of the radiator (120);
A plurality of pressure reducers (131, 132) that respectively depressurize the refrigerant flowing through the plurality of high-pressure side branch channels (121, 122);
A plurality of evaporators (141, 142) that evaporate the refrigerant flowing out from the plurality of pressure reducers (131, 132) and flow out to the compressor (110) side;
Among a plurality of the high-pressure side branch flow paths (121, 122), between the branch points (A) of the high-pressure side branch flow paths (121, 122) to the plurality of decompressors (131, 132). A supercritical refrigeration cycle comprising a plurality of internal heat exchangers (171, 172) for exchanging heat between flowing high-pressure refrigerant and low-pressure refrigerant flowing out from the plurality of evaporators (141, 142). apparatus. A gas-liquid separator (150) for collecting the refrigerant respectively flowing out from the plurality of evaporators (141, 142) and separating the refrigerant,
A plurality of low-pressure side branch flow paths (161, 162) branched at the refrigerant downstream side of the gas-liquid separator (150) and joined again to the compressor (110),
The low-pressure refrigerant that is heat-exchanged by the plurality of internal heat exchangers (171, 172) is a refrigerant that flows through the plurality of low-pressure side branch channels (161, 162), respectively. The supercritical refrigeration cycle apparatus described. A low-pressure side collective flow path (163) for collecting refrigerant flowing out from the plurality of evaporators (141, 142) and flowing into the compressor (110);
The supercritical fluid according to claim 1, wherein the low-pressure refrigerant heat-exchanged by the plurality of internal heat exchangers (171, 172) is a refrigerant that sequentially flows through the low-pressure side collecting flow path (163). Refrigeration cycle equipment. A low-pressure side collective flow path (163) for collecting refrigerant flowing out from the plurality of evaporators (141, 142) and flowing into the compressor (110);
The plurality of internal heat exchangers (171, 172) are integrally formed with a plurality of high-pressure channels (171a, 172a) through which the high-pressure refrigerant flows and one low-pressure channel (171b) through which the low-pressure refrigerant flows. In preparation for
2. The supercritical refrigeration cycle apparatus according to claim 1, wherein a refrigerant flowing through the low pressure side collecting flow path (163) flows through the low pressure flow path (171 b).   The internal heat exchangers (171 and 172) are arranged so that a plurality of the high-pressure channels (171a and 172a) surround the one low-pressure channel (171b), or one low-pressure channel ( The supercritical refrigeration cycle apparatus according to claim 4, wherein a plurality of the high-pressure flow paths (171a, 172a) are arranged in 171b). A vapor compression supercritical refrigeration cycle apparatus in which the high pressure in the refrigeration cycle is equal to or higher than the critical pressure of the refrigerant,
A compressor (110) for sucking and compressing the refrigerant;
A radiator (120) for radiating the refrigerant discharged from the compressor (110);
A decompressor (131) for decompressing the refrigerant flowing out of the radiator (120);
A plurality of low-pressure side branch channels (121b, 122b) branching on the refrigerant downstream side of the pressure reducer (131);
A plurality of evaporators (141, 142) that evaporate the refrigerant flowing through the plurality of low-pressure side branch channels (121b, 122b) and flow out to the compressor (110) side;
A plurality of internal heat exchangers for exchanging heat between the high-pressure refrigerant flowing from the radiator (120) to the decompressor (131) and the low-pressure refrigerant flowing out from the plurality of evaporators (141, 142). (171, 172),
The plurality of internal heat exchangers (171, 172) integrate a plurality of low-pressure channels (171b, 172b) through which the low-pressure refrigerant flows and one high-pressure channel (171a) through which the high-pressure refrigerant flows. A supercritical refrigeration cycle apparatus comprising:   The internal heat exchangers (171 and 172) are arranged so that a plurality of the low-pressure channels (171b and 172b) surround the one high-pressure channel (171a), or one high-pressure channel ( The supercritical refrigeration cycle apparatus according to claim 6, wherein a plurality of the low-pressure flow paths (171b, 172b) are arranged side by side in 171a). Refrigerants flowing out from the plurality of evaporators (141, 142) are joined together on the compressor (110) side,
The high-pressure refrigerant and the low-pressure refrigerant in each of the plurality of internal heat exchangers (171, 172) are formed so that the high-pressure refrigerant and the low-pressure refrigerant in each of the plurality of evaporators (141, 142) correspond to each other. The supercritical refrigeration cycle apparatus according to claim 1, wherein   Among the plurality of evaporators (141, 142), a gas-liquid separator (150) for separating gas and liquid of the refrigerant is provided on the refrigerant downstream side of at least one evaporator (141). The supercritical refrigeration cycle apparatus according to any one of claims 3 to 8.   The superheat degree of the low-pressure refrigerant after heat exchange of the internal heat exchanger (172) is controlled so as to become a predetermined value by the decompressor (132). Item 12. The supercritical refrigeration cycle apparatus according to any one of Items 9.   The pressure reducer (132) is a mechanical control valve (132) for adjusting the valve opening degree to reduce the pressure of the refrigerant according to the degree of superheat of the low-pressure refrigerant after the heat exchange. The supercritical refrigeration cycle apparatus according to claim 10.

Images