Refrigeration cycle device

Abstract

To provide a hybrid type refrigeration system which controls adsorption / desorption of a refrigerant in an adsorption type refrigeration cycle, by utilizing a pressure change of the refrigerant circulating in a steam compression type refrigeration cycle.SOLUTION: A refrigeration cycle device (1) includes a refrigeration circuit (11) and an adsorption material. The adsorption material adsorbs / desorbs a refrigerant circulating in a first unit. The refrigerant circuit (11) has a high pressure area and a low pressure area. The refrigeration cycle device (1) is operated at least under one condition out of a first condition and a second condition. Under the first condition, the pressure of the refrigerant in the high pressure area is equal to or less than a critical pressure of the refrigerant, and the temperature of the refrigerant in the high pressure area exceeds the critical temperature of the refrigerant. Under the second condition, the pressure of the refrigerant in the low pressure area is lower than a saturation pressure corresponding to the evaporation temperature of the refrigerant in the case where the adsorption material does not adsorb / desorb the refrigerant.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] It relates to a refrigeration cycle device.

Background Art

[0002] Conventionally, a hybrid refrigeration system configured by combining a vapor compression refrigeration cycle and an adsorption refrigeration cycle has been used. Patent Document 1 (International Publication No. 2009 / 145278) discloses a hybrid refrigeration system that alternately cools and heats a pair of adsorbers of an adsorption refrigeration cycle to alternately repeat adsorption and desorption of a refrigerant in order to reduce the mechanical work amount of a compressor of a vapor compression refrigeration cycle.

Summary of the Invention

Problems to be Solved by the Invention

[0003] A hybrid refrigeration system that controls the adsorption and desorption of a refrigerant in an adsorption refrigeration cycle by utilizing the pressure change of the refrigerant circulating in a vapor compression refrigeration cycle has not been conventionally used.

Means for Solving the Problems

[0004] The refrigeration cycle device of the first aspect includes a first unit and an adsorbent. The first unit has a compressor that compresses a refrigerant and an expansion mechanism that decompresses the refrigerant. The first unit constitutes a vapor compression refrigeration cycle in which the refrigerant circulates. The adsorbent adsorbs and desorbs the refrigerant circulating in the first unit. The first unit further has a high-pressure region and a low-pressure region. In the high-pressure region, the refrigerant flows after being compressed by the compressor and before being decompressed by the expansion mechanism. In the low-pressure region, the refrigerant flows after being decompressed by the expansion mechanism and before being compressed by the compressor. The refrigeration cycle device is operated under at least one of a first condition and a second condition. In the first condition, the pressure of the refrigerant in the high-pressure region is equal to or lower than the critical pressure of the refrigerant, and the temperature of the refrigerant in the high-pressure region exceeds the critical temperature of the refrigerant. In the second condition, the pressure of the refrigerant in the low-pressure region is lower than the saturation pressure corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant.

[0005] The refrigeration cycle device according to the first aspect has a vapor compression refrigeration cycle and can utilize the heat of adsorption and desorption of the refrigerant, with a lower operating pressure compared to a refrigeration cycle device having a vapor compression refrigeration cycle and no adsorbent. Therefore, the refrigeration cycle device according to the first aspect can suppress costs and improve the efficiency of the refrigeration cycle.

[0006] The refrigeration cycle device according to the second aspect includes a first unit and an adsorbent. The first unit has a compressor that compresses the refrigerant and an expansion mechanism that decompresses the refrigerant. The first unit constitutes a vapor compression refrigeration cycle in which the refrigerant circulates. The adsorbent adsorbs and desorbs the refrigerant circulating in the first unit. The first unit further has a high-pressure region and a low-pressure region. In the high-pressure region, the refrigerant flows after being compressed by the compressor and before being decompressed by the expansion mechanism. In the low-pressure region, the refrigerant flows after being decompressed by the expansion mechanism and before being compressed by the compressor. The refrigeration cycle device is operated under at least one of a first condition and a second condition. Under the first condition, the pressure of the refrigerant in the high-pressure region is equal to or lower than the critical pressure of the refrigerant, and the temperature of the refrigerant in the high-pressure region exceeds the saturation temperature of the refrigerant corresponding to the pressure of the refrigerant in the high-pressure region. Under the second condition, the pressure of the refrigerant in the low-pressure region is lower than the saturation pressure corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant.

[0007] The refrigeration cycle device according to the second aspect has a lower operating pressure compared to a refrigeration cycle device having a vapor compression refrigeration cycle and no adsorbent, and can utilize the heat of adsorption and desorption of the refrigerant. Therefore, the refrigeration cycle device according to the second aspect can suppress costs and improve the efficiency of the refrigeration cycle.

[0008] The refrigeration cycle device according to the third aspect is the refrigeration cycle device according to the second aspect, wherein the pressure of the refrigerant in the high-pressure region is equal to or lower than the saturation pressure corresponding to 65°C of R32 in a vapor compression refrigeration cycle in which R32 circulates.

[0009] The refrigeration cycle device from the fourth perspective is the refrigeration cycle device from the second perspective, and the pressure of the refrigerant in the high-pressure region is equal to or lower than the saturation pressure corresponding to 65 °C of R134a in a vapor compression refrigeration cycle in which R134a circulates.

[0010] The refrigeration cycle device from the fifth perspective is any one of the refrigeration cycle devices from the second to fourth perspectives, and the adsorbent includes a metal-organic framework containing metal ions and organic ligands.

[0011] The refrigeration cycle device from the sixth perspective is any one of the refrigeration cycle devices from the second to fifth perspectives, and the refrigerant is carbon dioxide.

[0012] The refrigeration cycle device from the seventh perspective includes a first unit and an adsorbent. The first unit has a compressor that compresses the refrigerant and an expansion mechanism that decompresses the refrigerant. The first unit constitutes a vapor compression refrigeration cycle in which the refrigerant circulates. The adsorbent adsorbs and desorbs the refrigerant circulating in the first unit. The first unit further has a high-pressure region and a low-pressure region. In the high-pressure region, the refrigerant flows after being compressed by the compressor and before being decompressed by the expansion mechanism. In the low-pressure region, the refrigerant flows after being decompressed by the expansion mechanism and before being compressed by the compressor. The refrigeration cycle device is operated under at least one of the first condition and the second condition. In the first condition, the pressure of the refrigerant in the high-pressure region is lower than the saturation pressure corresponding to the condensation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant. In the second condition, the pressure of the refrigerant in the low-pressure region is lower than the saturation pressure corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant.

[0013] Compared with a refrigeration cycle device that has a vapor compression refrigeration cycle and no adsorbent, the refrigeration cycle device from the seventh perspective has a lower operating pressure and can utilize the heat of adsorption and desorption of the refrigerant. Therefore, the refrigeration cycle device from the seventh perspective can suppress costs and improve the efficiency of the refrigeration cycle.

[0014] The refrigeration cycle device according to the eighth aspect is the refrigeration cycle device according to the seventh aspect, wherein the adsorbent contains a metal-organic framework containing metal ions and organic ligands.

[0015] The refrigeration cycle device according to the ninth aspect is the refrigeration cycle device according to the seventh aspect or the eighth aspect, wherein the refrigerant is ammonia or propane.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0017] (1) Overall Configuration The refrigeration cycle device 1 includes a hybrid cycle in which a vapor compression cycle and an adsorption cycle are combined. The vapor compression cycle is a vapor compression refrigeration cycle, which is a heat pump cycle that utilizes the transfer of latent heat generated when the refrigerant evaporates and condenses. The adsorption cycle is an adsorption refrigeration cycle, which is a heat pump cycle that utilizes the transfer of latent heat generated when the refrigerant is adsorbed by the adsorbent and when the refrigerant is desorbed from the adsorbent. The refrigeration cycle device 1 is, for example, an air conditioner and a refrigeration device.

[0018] As shown in FIG. 1, the refrigeration cycle device 1 includes a refrigerant circuit 11 and an adsorption circuit 12. The refrigerant circuit 11 constitutes a vapor compression cycle in which the refrigerant circulates. The adsorption circuit 12 constitutes an adsorption cycle in which the adsorbent circulates.

[0019] The refrigeration cycle device 1 may have only one circuit having at least one function of the refrigerant circuit 11 and the adsorption circuit 12. In this case, the refrigeration cycle device 1 may have a circuit in which a mixture of the refrigerant and the adsorbent circulates. Further, the refrigeration cycle device 1 may have a circuit in which only the refrigerant circulates and which is provided with a mechanism for the circulating refrigerant to come into contact with the adsorbent. In this case, the adsorbent does not circulate.

[0020] The refrigeration cycle device 1 may have two circuits including a circuit having the function of the refrigerant circuit 11 and a circuit having the function of the adsorption circuit 12. In this case, the refrigeration cycle device 1 is provided with a mechanism for the refrigerant circulating in the refrigerant circuit 11 to come into contact with the adsorbent circulating in the adsorption circuit 12. In FIG. 1, for the sake of explanation, the refrigerant circuit 11 and the adsorption circuit 12 are depicted as independent circuits.

[0021] The refrigeration cycle device 1 has an adsorption section 21 and a desorption section 22. Both the adsorption section 21 and the desorption section 22 include a part of the refrigerant circuit 11 and a part of the adsorption circuit 12. The refrigerant can freely flow back and forth between the refrigerant circuit 11 and the adsorption circuit 12 in the adsorption section 21 and the desorption section 22. The adsorbent cannot flow back and forth between the refrigerant circuit 11 and the adsorption circuit 12. In the adsorption section 21, the refrigerant flowing from the refrigerant circuit 11 into the adsorption circuit 12 adsorbs to the adsorbent flowing through the adsorption circuit 12. In the desorption section 22, the refrigerant desorbed from the adsorbent flowing through the adsorption circuit 12 flows into the refrigerant circuit 11 from the adsorption circuit 12.

[0022] The refrigerant circuit 11 has a compressor 31 and an expansion mechanism 32. The compressor 31 compresses the refrigerant circulating in the refrigerant circuit 11. The expansion mechanism 32 decompresses the refrigerant circulating in the refrigerant circuit 11. The compressor 31 is, for example, a rotary compressor. The expansion mechanism 32 is, for example, an electronic expansion valve. In the refrigerant circuit 11, the refrigerant is compressed by the compressor 31, passes through the adsorption section 21, decompressed by the expansion mechanism 32, passes through the desorption section 22, and is compressed again by the compressor 31.

[0023] The refrigerant circuit 11 has a high-pressure region and a low-pressure region. In the high-pressure region, the refrigerant flows after being compressed by the compressor 31 and before being decompressed by the expansion mechanism 32. In the low-pressure region, the refrigerant flows after being decompressed by the expansion mechanism 32 and before being compressed by the compressor 31. The high-pressure region corresponds to a part of the refrigerant circuit 11 included in the adsorption section 21. The low-pressure region corresponds to a part of the refrigerant circuit 11 included in the desorption section 22.

[0024] The refrigerant circulating in the refrigerant circuit 11 is carbon dioxide. The refrigerant may be ammonia or propane.

[0025] The adsorption circuit 12 has a pressure booster 41 and a pressure reducer 42. The pressure booster 41 boosts the pressure of the adsorbent circulating in the adsorption circuit 12. The pressure reducer 42 reduces the pressure of the adsorbent circulating in the adsorption circuit 12. The pressure booster 41 is, for example, a powder pump. The pressure reducer 42 is, for example, a powder valve. In the adsorption circuit 12, the adsorbent is boosted in pressure by the pressure booster 41, passes through the adsorption section 21, reduced in pressure by the pressure reducer 42, passes through the desorption section 22, and is boosted in pressure again by the pressure booster 41. Depending on the configuration of the refrigeration cycle device 1, the adsorption circuit 12 may not have the pressure booster 41 and the pressure reducer 42.

[0026] The adsorption circuit 12 may further have a heat exchanger 43. The heat exchanger 43 performs heat exchange between the upstream side of the pressure booster 41 and the upstream side of the pressure reducer 42. The heat exchanger 43 transfers part of the heat of the adsorbent flowing between the adsorption section 21 and the pressure reducer 42 to the adsorbent flowing between the desorption section 22 and the pressure booster 41.

[0027] The adsorbent circulating in the adsorption circuit 12 contains a metal-organic framework containing metal ions and organic ligands. A metal-organic framework (MOF: Metal-Organic Framework) is a porous material with a very large specific surface area obtained by the reaction of metal ions and organic ligands. In a metal-organic framework, when an organic ligand links with metal ions, a polymer structure with innumerable openings inside is obtained. The metal-organic framework can adjust the aperture diameter and topology by selectively selecting and combining metal ions and organic ligands respectively. The metal-organic framework can adjust the aperture diameter by the selection and combination of metal ions and organic ligands, and can selectively adsorb the target substance. The metal-organic framework is used, for example, as a porous material having functions of selective storage and separation of molecules and ions. In the present embodiment, the metal-organic framework is used as an adsorbent for adsorbing and desorbing a refrigerant. The metal-organic frameworks are, for example, MOF-5 and MOF-200. The adsorbent is, for example, a powder of a metal-organic framework.

[0028] (2) Operation The adsorbent adsorbs and desorbs the refrigerant circulating in the refrigerant circuit 11. The adsorbent adsorbs and desorbs the refrigerant according to the change in the pressure of the refrigerant circulating in the refrigerant circuit 11. Specifically, the adsorbent adsorbs the refrigerant under high pressure and desorbs the refrigerant under low pressure.

[0029] It is assumed that the high-pressure region of the refrigerant circuit 11 is filled with a refrigerant at a pressure pH and a temperature TH. It is assumed that the low-pressure region of the refrigerant circuit 11 is filled with a refrigerant at a pressure pL and a temperature TL. The pressure pH is higher than the pressure pL. The temperature TH is higher than the temperature TL. The adsorbent adsorbs the refrigerant in the high-pressure region of the refrigerant circuit 11. The adsorbent desorbs the refrigerant in the low-pressure region of the refrigerant circuit 11. In the adsorption section 21, the refrigerant flowing in the high-pressure region of the refrigerant circuit 11 flows into the adsorption circuit 12 and is adsorbed by the adsorbent. In the desorption section 22, the refrigerant desorbed from the adsorbent flowing through the adsorption circuit 12 flows into the low-pressure region of the refrigerant circuit 11.

[0030] The operation of the heat pump cycle of the refrigeration cycle device 1 will be described with reference to FIGS. 1-4. FIGS. 1-4 show the refrigerant cycle a→b→c→d→a in the refrigerant circuit 11 and the adsorbent cycle a´→b´→c´→d´→a´ in the adsorption circuit 12. The graph in FIG. 2 shows the adsorption amount, which is the mass of the refrigerant adsorbed on the adsorbent per unit mass, and the change in the pressure of the refrigerant adsorbed on the adsorbent in the heat pump cycle. The graph in FIG. 3 shows the adsorption amount of the adsorbent and the change in the enthalpy of the refrigerant adsorbed on the adsorbent in the heat pump cycle. The graph in FIG. 4 shows the change in the pressure and the enthalpy of the refrigerant in the heat pump cycle. In the refrigeration cycle device 1, it is assumed that heat can freely flow between the refrigerant circuit 11 and the adsorption circuit 12.

[0031] In the refrigerant circuit 11, the refrigerant is compressed by the compressor 31 (a→b). In the adsorption circuit 12, the adsorbent is pressurized by the booster 41 (a´→b´). As a result, the pressures of the refrigerant and the adsorbent increase from pL to pH. In this process, a part Q1 of the heat generated by the adiabatic compression of the refrigerant is given to the adsorbent. In other words, the refrigerant is cooled by giving heat to the adsorbent while being compressed. As a result, the temperatures of the refrigerant and the adsorbent increase from TL to TH.

[0032] Next, in the adsorption unit 21, the refrigerant gradually adsorbs to the adsorbent while releasing heat Q2 (b´→c´). In this process, the adsorption amount of the adsorbent increases from mL to mH. As a result, in the adsorption unit 21, most of the refrigerant in the refrigerant circuit 11 adsorbs to the adsorbent in the adsorption circuit 12. In FIG. 1, as shown by the hatched arrows in the adsorption unit 21, in the adsorption unit 21, the refrigerant in the refrigerant circuit 11 moves to the adsorption circuit 12 and adsorbs to the adsorbent.

[0033] Next, in the adsorption circuit 12, the adsorbent is depressurized by the vacuum pump 42 (c´→d´). As a result, the pressure of the adsorbent drops from pH to pL. During this process, due to the isenthalpic expansion of the refrigerant desorbed from the adsorbent, the temperature of the adsorbent drops from TH to TL. Also, due to the temperature difference between the refrigerant and the adsorbent, the depressurized adsorbent in the adsorption circuit 12 is cooled and gives heat Q3 to the refrigerant in the refrigerant circuit 11. Further, heat Q5 is given from the adsorbent before being depressurized to the adsorbent before being pressurized by the heat exchanger 43.

[0034] Next, in the desorption section 22, the refrigerant gradually desorbs from the adsorbent while absorbing heat Q4 (d´→a´). During this process, the adsorption amount of the adsorbent drops from mH to mL. As a result, most of the refrigerant adsorbed on the adsorbent in the adsorption circuit 12 desorbs and flows into the refrigerant circuit 11. In FIG. 1, as indicated by the hatched arrows in the desorption section 22, in the desorption section 22, the refrigerant desorbed from the adsorbent in the adsorption circuit 12 moves to the refrigerant circuit 11.

[0035] As shown in FIG. 2, in the adsorption process (b´→c´) where the refrigerant adsorbs to the adsorbent, the pressure is pH, and the adsorption amount of the adsorbent increases from mL to mH. In the desorption process (d´→a´) where the refrigerant desorbs from the adsorbent, the pressure is pL, and the adsorption amount of the adsorbent drops from mH to mL. As shown in FIG. 3, in the adsorption process, the enthalpy drops by Δh1. In the desorption process, the enthalpy rises by Δh2. In the adsorption process, the heat Q2 released from the adsorption section 21 is proportional to Δh1. In the desorption process, the heat Q4 absorbed by the desorption section 22 is proportional to Δh2.

[0036] Let the change in enthalpy due to heat exchange by the heat exchanger 43 be Δh3. In the pressurization process (a´→b´) of the adsorbent, let the change in enthalpy due to heating of the adsorbent be Δh4. In the depressurization process (c´→d´) of the adsorbent, let the change in enthalpy due to cooling of the adsorbent be Δh5. As shown in FIG. 4, the change in total enthalpy in the compression process (a→b) of the refrigerant is represented by Δh4 - Δh3. The change in total enthalpy in the depressurization process (c´→d´) of the adsorbent is represented by Δh5 - Δh3. In FIG. 4, the state change of the refrigerant during adiabatic compression is indicated by a dashed arrow, and the state change of the refrigerant during isenthalpic expansion is indicated by a dash-dotted arrow.

[0037] FIG. 5 shows isotherms during adsorption and desorption of the refrigerant, which are suitable for the heat pump cycle of the refrigeration cycle device 1. In FIG. 5, the isotherm at temperature TH is shown by a solid line, and the isotherm at temperature TL is shown by a dash-dotted line. In the adsorption process (b´→c´), when the refrigerant is adsorbed by the adsorbent at pressure pH and temperature TH, it is preferable that the adsorption amount of the adsorbent increases from mL to mH at a pressure between pL and pH on the isotherm at temperature TH. In the desorption process (d´→a´), when the refrigerant is desorbed from the adsorbent at pressure pL and temperature TL, it is preferable that the adsorption amount of the adsorbent decreases from mH to mL at a pressure between pL and pH on the isotherm at temperature TL.

[0038] (3) Detailed Configuration The specific configuration of the refrigeration cycle device 1 shown in FIG. 1 will be described with reference to FIG. 6.

[0039] The refrigeration cycle device 301 shown in FIG. 6 has a refrigerant circuit 311 through which the refrigerant circulates. The refrigerant circuit 311 has the functions of both the refrigerant circuit 11 and the adsorption circuit 12 in FIG. 1. The adsorbent flows through a part of the refrigerant circuit 311 together with the refrigerant. In other words, in the refrigeration cycle device 301, a mixture of the refrigerant and the adsorbent circulates in the refrigerant circuit 311.

[0040] The refrigerant circuit 311 includes a compressor 331, an expansion mechanism 332, a first heat exchanger 333, a second heat exchanger 334, a switching unit 335, a first fan 336, a second fan 337, a booster 341, and a separator 351. The compressor 331 corresponds to the compressor 31 in FIG. 1. The booster 341 corresponds to the booster 41 in FIG. 1. The expansion mechanism 332 has the functions of both the expansion mechanism 32 and the pressure reducer 42 in FIG. 1.

[0041] The switching unit 335 switches the flow direction of the mixture of the refrigerant and the adsorbent circulating in the refrigerant circuit 311. The switching unit 335 is, for example, a four-way switching valve. The switching unit 335 switches between a first mode with the flow direction indicated by the solid line in FIG. 6 and a second mode with the flow direction indicated by the broken line in FIG. 6. In the first mode, the discharge sides of the compressor 331 and the booster 341 are connected to the first heat exchanger 333, and the suction sides of the compressor 331 and the booster 341 are connected to the second heat exchanger 334. In the second mode, the discharge sides of the compressor 331 and the booster 341 are connected to the second heat exchanger 334, and the suction sides of the compressor 331 and the booster 341 are connected to the first heat exchanger 333.

[0042] The separator 351 is provided between the suction sides of the compressor 331 and the booster 341 and the switching unit 335.

[0043] The separator 351 separates the mixture of the low-pressure refrigerant and the adsorbent circulating in the refrigerant circuit 311 into the refrigerant and the adsorbent. The separator 351 separates the refrigerant and the adsorbent by, for example, centrifugal separation. The refrigerant separated by the separator 351 is compressed in the compressor 331. The adsorbent separated by the separator 351 is boosted by the booster 341. As shown in FIG. 6, the adsorbent boosted by the booster 341 merges with the refrigerant compressed in the compressor 331. After merging, the refrigerant and the adsorbent are sent to the switching unit 335. In this way, the refrigerant circuit 311 branches at the separator 351 and merges between the compressor 331 / booster 341 and the switching unit 335.

[0044] In the first heat exchanger 333, high-pressure refrigerant is adsorbed by the adsorbent in the first mode, and low-pressure refrigerant is desorbed from the adsorbent in the second mode. In the second heat exchanger 334, low-pressure refrigerant is desorbed from the adsorbent in the first mode, and high-pressure refrigerant is adsorbed by the adsorbent in the second mode. In the first heat exchanger 333 and the second heat exchanger 334, the refrigerant is heated when it is adsorbed by the adsorbent, or the refrigerant is cooled when it is desorbed from the adsorbent. As a result, heat exchange is performed between the heated or cooled refrigerant and air in the first heat exchanger 333 and the second heat exchanger 334. The first fan 336 sends the air heat-exchanged in the first heat exchanger 333 to a predetermined location. The second fan 337 sends the air heat-exchanged in the second heat exchanger 334 to a predetermined location.

[0045] In this way, in the refrigeration cycle device 301, in the process of the mixture of the refrigerant and the adsorbent circulating in the refrigerant circuit 311, the refrigerant is heated or cooled, and the air heat-exchanged with the refrigerant is sent to a predetermined location. The case where the refrigeration cycle device 301 is an air conditioner will be described. Assume that the first heat exchanger 333 is an indoor heat exchanger and the second heat exchanger 334 is an outdoor heat exchanger. When this refrigeration cycle device 301 performs heating operation, by switching to the first mode, the refrigerant is adsorbed by the adsorbent in the first heat exchanger 333 and the refrigerant is heated. The air heated by heat-exchanging with the refrigerant is sent to a predetermined location by the first fan 336.

[0046] The refrigeration cycle device 301 may further include a member that separates the mixture of the high-pressure refrigerant and the adsorbent circulating in the refrigerant circuit 311 into the refrigerant and the adsorbent. In this case, the separated refrigerant is depressurized by a member corresponding to the expansion mechanism 332 in FIG. 6, and the separated adsorbent is depressurized by a member corresponding to the decompressor 42 in FIG. 1.

[0047] The specific configuration of the refrigeration cycle device 1 shown in FIG. 1 is not limited to the refrigeration cycle device 301 shown in FIG. 6. For example, the refrigeration cycle device 1 may not have members corresponding to the booster 341 and the separator 351 of the refrigeration cycle device 301 and may have one circuit in which the mixture of the refrigerant and the adsorbent circulates.

[0048] Further, the refrigeration cycle device 1 may have two circuits including a refrigerant circuit through which the refrigerant circulates and an adsorbent circuit through which the adsorbent circulates. In this case, the refrigeration cycle device 1 has a configuration that allows the refrigerant flowing through the refrigerant circuit to freely enter and exit the adsorbent circuit. For example, the refrigeration cycle device 1 has a mixing section in which the refrigerant circuit and the adsorbent circuit are partitioned by a gas permeable membrane through which the refrigerant can pass but the adsorbent cannot pass. The mixing section corresponds to the adsorption section 21 and the desorption section 22 shown in FIG. 1. In the mixing section, the refrigerant and the adsorbent are mixed, and the refrigerant is adsorbed or desorbed.

[0049] Further, the refrigeration cycle device 1 may have a configuration in which two adsorption sections (a first adsorption section and a second adsorption section) are installed in the refrigerant circuit through which the refrigerant circulates. The first adsorption section and the second adsorption section have an adsorbent that comes into contact with the refrigerant circulating in the refrigerant circuit. In this case, the refrigeration cycle device 1 has a configuration capable of switching between a first mode in which the first adsorbent adsorbs the refrigerant and the second adsorbent desorbs the refrigerant, and a second mode in which the first adsorbent desorbs the refrigerant and the second adsorbent adsorbs the refrigerant.

[0050] (4) Operating conditions The refrigeration cycle device 1 is operated so that at least one of the first condition and the second condition is satisfied. Next, specific examples of the first condition and the second condition will be described with reference to a Mollier diagram (p-h diagram) representing the state of the refrigerant in the refrigeration cycle. In FIGS. 7 and 8, a saturated liquid line L1, a dry saturated vapor line L2, and a critical point CP of the refrigerant are drawn. The critical point CP is the end point on the high-pressure side of the saturated liquid line L1 and the dry saturated vapor line L2. In FIG. 7, isotherms at temperatures TH, TC, and TS are drawn as dashed-dotted lines.

[0051] (4-1) First embodiment In this embodiment, the refrigerant used by the refrigeration cycle device 1 is carbon dioxide. The first condition and the second condition are as follows. · First condition: The pressure of the refrigerant in the high-pressure region is equal to or lower than the critical pressure of the refrigerant, and the temperature of the refrigerant in the high-pressure region exceeds the critical temperature of the refrigerant. · Second condition: The pressure of the refrigerant in the low-pressure region is lower than the saturation pressure corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant.

[0052] In FIG. 7, the refrigeration cycle C1 of the refrigeration cycle device 1 is shown by a solid line, and the refrigeration cycle C2 of a refrigeration cycle device having only a vapor compression cycle is shown by a broken line. Each state of the refrigerant cycle a→b→c→d→a of the refrigerant circuit 11 in FIG. 1 is shown in the refrigeration cycle C1.

[0053] In the first condition, the pressure PH of the refrigerant in the high-pressure region of the refrigeration cycle C1 is equal to or lower than the critical pressure PC of the refrigerant. The critical pressure PC is the pressure at the critical point CP. Also, in the first condition, the temperature TH of the refrigerant in the high-pressure region of the refrigeration cycle C1 exceeds the critical temperature TC of the refrigerant. The temperature TH is the temperature of the high-temperature and high-pressure refrigerant compressed by the compressor 31, and is the temperature of the refrigerant in the state b of the refrigeration cycle C1. The critical temperature TC is the temperature at the critical point CP. In FIG. 7, the temperature TH indicated by the isotherm passing through the state b is higher than the temperature TC indicated by the isotherm passing through the critical point CP.

[0054] In the second condition, the pressure PL of the refrigerant in the low-pressure region of the refrigeration cycle C1 is lower than the saturation pressure PL´ corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant. The saturation pressure PL´ corresponds to the pressure in the low-pressure region of the refrigeration cycle C2.

[0055] The value of the pressure PH of the refrigerant in the high-pressure region of the refrigeration cycle C1 may be set as appropriate. For example, the pressure PH is set to be equal to or lower than the saturation pressure corresponding to 65°C of R32 in a vapor compression refrigeration cycle in which R32 circulates. Also, the pressure PH is set to be equal to or lower than the saturation pressure corresponding to 65°C of R134a in a vapor compression refrigeration cycle in which R134a circulates.

[0056] (4-2) Second embodiment In this embodiment, the refrigerant used in the refrigeration cycle device 1 is propane. The first condition and the second condition are as follows. · First condition: The pressure of the refrigerant in the high-pressure region is lower than the saturation pressure corresponding to the condensation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant. · Second condition: The pressure of the refrigerant in the low-pressure region is lower than the saturation pressure corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant.

[0057] In FIG. 8, the refrigeration cycle C3 of the refrigeration cycle device 1 is shown by a solid line, and the refrigeration cycle C4 of a refrigeration cycle device having only a vapor compression cycle is shown by a broken line. Each state of the cycle a→b→c→d→a of the refrigerant in the refrigerant circuit 11 of FIG. 1 is shown in the refrigeration cycle C3.

[0058] In the first condition, the pressure PH of the refrigerant in the high-pressure region of the refrigeration cycle C3 is lower than the saturation pressure PH' corresponding to the condensation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant. The saturation pressure PH' corresponds to the pressure in the high-pressure region of the refrigeration cycle C4.

[0059] In the second condition, the pressure PL of the refrigerant in the low-pressure region of the refrigeration cycle C3 is lower than the saturation pressure PL' corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb and desorb the refrigerant. The saturation pressure PL' corresponds to the pressure in the low-pressure region of the refrigeration cycle C4.

[0060] (5) Features In FIGS. 7 and 8, the operating pressure of the refrigeration cycle device 1 is PH, and the operating pressure of the conventional refrigeration cycle device is PH'. The operating pressure PH is lower than the operating pressure PH'. Therefore, the refrigeration cycle device 1 has a smaller operating pressure compared to a conventional refrigeration cycle device having a vapor compression refrigeration cycle and no adsorbent. For example, when the refrigerant is carbon dioxide, as shown in FIG. 7, the operating pressure PH' of the conventional refrigeration cycle device is about 10 MPa, and the operating pressure PH of the refrigeration cycle device 1 is about 1.5 MPa. The operating pressure is the pressure of the compressed refrigerant in the refrigeration cycle. The higher the operating pressure, the greater the mechanical work of the compressor, and the higher the pressure resistance (design pressure) required for the members constituting the refrigerant circuit such as the casing of the compressor. Therefore, the higher the operating pressure, the higher the cost of the electric power for driving the compressor and the cost of the members constituting the system tend to be.

[0061] Therefore, since the refrigeration cycle device 1 can operate at a lower operating pressure than the conventional refrigeration cycle device, the manufacturing cost and the operation cost can be reduced. Further, by reducing the design pressure, the refrigeration cycle device 1 can make the members such as the casing of the compressor compact and improve the reliability of the system.

[0062] Also, when the refrigeration cycle device 1 is an air conditioner, the refrigeration cycle device 1 can increase the heating and cooling capacity by using the adsorption heat and desorption heat of the refrigerant for heating and cooling. Therefore, the refrigeration cycle device 1 can improve the efficiency of the refrigeration cycle and reduce the operation cost compared to the conventional refrigeration cycle device by controlling the adsorption heat and desorption heat of the refrigerant.

[0063] (6) Modification (6-1) Modification A In the first embodiment, the first condition may be that the pressure of the refrigerant in the high-pressure region is equal to or lower than the critical pressure of the refrigerant, and the temperature of the refrigerant in the high-pressure region exceeds the saturation temperature of the refrigerant corresponding to the pressure of the refrigerant in the high-pressure region.

[0064] Under this first condition, the pressure PH of the refrigerant in the high-pressure region of the refrigeration cycle C1 is equal to or lower than the critical pressure PC of the refrigerant. Further, the temperature TH of the refrigerant in the high-pressure region of the refrigeration cycle C1 exceeds the saturation temperature TS of the refrigerant corresponding to the pressure of the refrigerant in the high-pressure region. The temperature TH is the temperature of the high-temperature and high-pressure refrigerant compressed by the compressor 31, and is the temperature of the refrigerant in the state b of the refrigeration cycle C1. As shown in FIG. 7, the saturation temperature TS corresponds to the temperature at the point where the line of the pressure PH of the refrigerant in the high-pressure region of the refrigeration cycle C1 intersects the dry saturated vapor line L2.

[0065] (6-2) Modified Example B In the second embodiment, the refrigerant used in the refrigeration cycle device 1 may be ammonia.

[0066] (6-3) Modified Example C The adsorbent used in the refrigeration cycle devices 1 and 301 is a metal-organic framework. However, materials other than metal-organic frameworks may be used as the adsorbent.

[0067] As described above, the embodiments of the present disclosure have been described. It will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims.

Description of Reference Numerals

[0068] 1, 301: Refrigeration cycle device 11, 311: Refrigerant circuit (first unit) 31, 331: Compressor 32, 332: Expansion mechanism

Prior Art Documents

Patent Documents

[0069]

Patent Document 1

Claims

1. A first unit (11,311) having a compressor (31,331) for compressing a refrigerant, An adsorbent that adsorbs and desorbs the refrigerant, Equipped with, The first unit is, A high-pressure region through which the refrigerant compressed by the compressor flows, A low-pressure region through which the refrigerant flows before being compressed by the compressor, It further possesses, The first condition is that the pressure of the refrigerant in the high-pressure region is below the critical pressure of the refrigerant, and the temperature of the refrigerant in the high-pressure region exceeds the critical temperature of the refrigerant, and The second condition is that the pressure of the refrigerant in the low-pressure region is lower than the saturation pressure corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb or desorb the refrigerant. Operated under at least one of the following conditions: Refrigeration cycle device (1,301).

2. A first unit (11,311) having a compressor (31,331) for compressing a refrigerant, An adsorbent that adsorbs and desorbs the refrigerant, Equipped with, The first unit is, A high-pressure region through which the refrigerant compressed by the compressor flows, A low-pressure region through which the refrigerant flows before being compressed by the compressor, It further possesses, The first condition is that the pressure of the refrigerant in the high-pressure region is less than or equal to the critical pressure of the refrigerant, and the temperature of the refrigerant in the high-pressure region exceeds the saturation temperature of the refrigerant corresponding to the pressure of the refrigerant in the high-pressure region, The second condition is that the pressure of the refrigerant in the low-pressure region is lower than the saturation pressure corresponding to the evaporation temperature of the refrigerant when the adsorbent does not adsorb or desorb the refrigerant. Operated under at least one of the following conditions: Refrigeration cycle device (1,301).

3. The pressure of the refrigerant in the high-pressure region is below the saturation pressure corresponding to 65°C of R32 in a vapor compression type refrigeration cycle in which R32 circulates. A refrigeration cycle apparatus according to claim 1 or 2.

4. The pressure of the refrigerant in the high-pressure region is below the saturation pressure of R134a corresponding to 65°C in a vapor compression type refrigeration cycle in which R134a circulates. A refrigeration cycle apparatus according to claim 1 or 2.

5. The adsorbent includes a metal-organic structure containing metal ions and an organic ligand. A refrigeration cycle apparatus according to claim 1 or 2.

6. The aforementioned refrigerant is carbon dioxide. A refrigeration cycle apparatus according to claim 1 or 2.

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