Refrigeration equipment

Abstract

In refrigeration systems equipped with an adsorption refrigeration cycle, repeated starting and stopping of the compressor during operation may reduce the reliability of the compressor. [Solution] The refrigeration system 100 comprises a refrigerant flow path 111, a compressor 131, a first adsorbent 121, a second adsorbent 122, a switching mechanism 135, a bypass flow path 211, a bypass valve 212, and a control unit 105. The first adsorbent 121 and the second adsorbent 122 have an adsorbent material 181. The bypass flow path 211 connects the first adsorbent 121 and the second adsorbent 122 without passing through the compressor 131. The bypass valve 212 is provided in the bypass flow path 211. The control unit 105 repeatedly performs a first cycle operation in which the refrigerant flow path 111 is sequentially switched in the order of first state, third state, second state, and third state. In the third state, the bypass valve 212 is at the first opening. The control unit 105 continuously drives the compressor 131 while the first cycle operation is being performed.

Description

Technical Field

[0004]

[0001] It relates to a refrigeration device.

Background Art

[0002] Conventionally, a refrigeration device having an adsorption refrigeration cycle has been used. As such a refrigeration device, Patent Document 1 (U.S. Patent Application Publication No. 2023 / 0417459) discloses a heat source side circuit having a pair of adsorbers in which adsorption and desorption of a refrigerant are alternately repeated, and a utilization side circuit in which a heat medium for recovering the adsorption heat or desorption heat of the refrigerant circulates. In the heat source side circuit, a mode in which the refrigerant is adsorbed in one adsorber and desorbed in the other adsorber, and a mode in which the refrigerant is desorbed in the one adsorber and adsorbed in the other adsorber are alternately switched. Thereby, in the utilization side circuit, heat is continuously recovered from the heat source side circuit by the heat medium.

Summary of the Invention

Problems to be Solved by the Invention

[0003] If control is performed to stop the compressor every time the mode of the heat source side circuit is switched, the compressor may be repeatedly started and stopped during the operation of the refrigeration device, which may reduce the reliability of the compressor.

Means for Solving the Problems

[0004] The refrigeration system of the first aspect comprises a refrigerant flow path through which the refrigerant flows, a compressor, a first adsorbent, a second adsorbent, a switching mechanism, a bypass flow path, a bypass valve, and a control unit. The compressor draws in low-pressure refrigerant, compresses it, and discharges it as high-pressure refrigerant. The first and second adsorbents have adsorbents that adsorb and desorb refrigerant in accordance with changes in the refrigerant pressure. The first and second adsorbents recover the heat generated when the adsorbent material adsorbs the refrigerant and the cold generated when the adsorbent material desorbs the refrigerant. The bypass flow path connects the first and second adsorbents without passing through the compressor. A bypass valve is provided in the bypass flow path. The bypass valve's opening degree is adjustable. The control unit controls the switching mechanism and the bypass valve to switch the refrigerant flow path between a first state, a second state, and a third state. The first state is a state in which the first adsorbent is under high pressure and the second adsorbent is under low pressure. The second state is one in which the first adsorbent is under low pressure and the second adsorbent is under high pressure. The third state is one in which the bypass valve is open to the first degree and the first and second adsorbents are in communication. The control unit repeatedly performs the first cycle operation, sequentially switching the refrigerant flow path in the order of the first state, the third state, the second state, and the third state. The control unit continuously drives the compressor while the first cycle operation is being performed.

[0005] The refrigeration system described in the first aspect can continuously drive the compressor, thus suppressing a decrease in the reliability of the compressor.

[0006] The refrigeration system in the second perspective is the same as the refrigeration system in the first perspective, wherein the control unit changes the rotational speed of the compressor during the execution of the first cycle.

[0007] The refrigeration system from the second perspective can maintain the reliability of the compressor while performing control based on a predetermined capacity by controlling the rotational speed of the compressor and maintaining the pressure in the first and second adsorbents within a predetermined range.

[0008] The refrigeration system of the third aspect is the refrigeration system of the second aspect, wherein the control unit makes the average rotational speed of the compressor in the first period higher than the average rotational speed of the compressor in the second period following the first period, while the refrigerant flow path is in the first or second state. The first period includes the time when the first or second state begins. The second period includes the time when the first or second state ends.

[0009] The refrigeration system of the fourth aspect is a refrigeration system of the second or third aspect, wherein the control unit reduces the rotational speed of the compressor when the pressure in the first or second adsorbent reaches a predetermined value while the refrigerant flow path is in the first or second state.

[0010] The refrigeration system of the fifth aspect is a refrigeration system of any one of the second to fourth aspects, wherein the control unit makes the average rotational speed of the compressor when the refrigerant flow path is in the first or second state higher than the rotational speed of the compressor when the refrigerant flow path is in the third state.

[0011] The refrigeration system of the sixth aspect is a refrigeration system of any one of the second to fifth aspects, wherein the control unit changes the opening degree of the bypass valve during the execution of the first cycle operation. The control unit sets the opening degree of the bypass valve to zero for a predetermined period including the time when the first or second state begins, while the refrigerant flow path is in the first or second state.

[0012] The refrigeration system in the sixth aspect can maintain the reliability of the compressor while performing control based on a predetermined capacity by controlling the opening degree of the bypass valve to maintain the pressure in the first and second adsorbents within a predetermined range.

[0013] The refrigeration system of the seventh aspect is the refrigeration system of the sixth aspect, wherein the control unit performs a first control, which reduces the rotational speed of the compressor while the refrigerant flow path is in the first or second state. The control unit performs a second control, which increases the opening degree of the bypass valve from zero while the refrigerant flow path is in the first or second state. The control unit starts the second control after starting the first control.

[0014] The refrigeration apparatus of the eighth aspect is the refrigeration apparatus of the seventh aspect, wherein the control unit starts the second control when the pressure in the first adsorbent or the second adsorbent reaches a predetermined value.

[0015] The refrigeration system of the ninth aspect is a refrigeration system of the seventh or eighth aspect, wherein the control unit starts the second control after the compressor rotation speed has decreased to a first value during the execution of the first control.

[0016] The refrigeration device of the 10th aspect is a refrigeration device of any one of the 7th to 9th aspects, wherein the control unit, when executing the second control, raises the opening degree of the bypass valve from zero to a second opening degree that is smaller than the first opening degree.

[0017] The refrigeration system of the 11th aspect is a refrigeration system of any one of the 7th to 10th aspects, wherein the control unit starts the second control when the pressure in the first adsorbent rises to a second value or the pressure in the second adsorbent falls to a third value while the refrigerant flow path is in a first state. The control unit starts the second control when the pressure in the second adsorbent rises to a second value or the pressure in the first adsorbent falls to a third value while the refrigerant flow path is in a second state.

[0018] The refrigeration apparatus of the 12th aspect is a refrigeration apparatus of any one of the seventh to 11th aspects, wherein the control unit performs a first control so as to increase the pressure in the first adsorbent while the refrigerant flow path is in a first state. The control unit performs a first control so as to increase the pressure in the second adsorbent while the refrigerant flow path is in a second state.

[0019] The refrigeration apparatus of the 13th aspect is a refrigeration apparatus of any one of the first to 12 aspects, wherein the adsorbent includes a metal-organic structure containing metal ions and an organic ligand.

[0020] A refrigeration apparatus of the 14th aspect is a refrigeration apparatus of any one of the first to 13 aspects, wherein the refrigerant includes at least one of carbon dioxide, hydrocarbons, ammonia, water, HFCs, and HFOs. [Brief explanation of the drawing]

[0021] [Figure 1] It is a schematic diagram of the refrigeration device 100 of the first embodiment. [Figure 2] It is a block diagram of the refrigeration device 100 of the first embodiment. [Figure 3] It is a schematic diagram of the first adsorber 121 and the second adsorber 122 of the first embodiment. [Figure 4] It is a time chart of the control of the refrigeration device 100 of the first embodiment. [Figure 5] It is a time chart of the control of the refrigeration device 100 of the second embodiment. [Figure 6] It is a time chart of the control of the refrigeration device 100 of the third embodiment. [Figure 7] It is a flowchart of the control of the first state and the second state of the third embodiment. [Figure 8] [[ID=?]]It is a flowchart of the control of the third state of the third embodiment.

Embodiments for Implementing the Invention

[0022] - First Embodiment - (1) Overall Configuration of the Refrigeration Device 100 As shown in FIG. 1, the refrigeration device 100 of the first embodiment includes a heat source side circuit 101, a utilization side circuit 102, a first fan 143, and a second fan 153. The heat source side circuit 101 has a refrigerant flow path 111 through which refrigerant flows. The utilization side circuit 102 has a heat medium flow path 112 through which a heat medium flows. In FIG. 1, the refrigerant flow path 111 is drawn with a thick line. The refrigeration device 100 is, for example, an air conditioner. When the refrigeration device 100 is an air conditioner, one of the first fan 143 and the second fan 153 is provided in the indoor unit, and the other is provided in the outdoor unit.

[0023] Please note that there seems to be a mistake in the original text where the ID for the "It is a flowchart of the control of the third state of the third embodiment." is marked as 25 in the original but translated as 24 in the above. It should be corrected according to the correct ID in the original text.The refrigerant flowing through the refrigerant channel 111 includes at least one of carbon dioxide, hydrocarbons, ammonia, water, HFCs (hydrofluorocarbons), and HFOs (hydrofluoroolefins). The hydrocarbons are selected from the group consisting of, for example, propane, butane, and isobutane.

[0024] The heat transfer medium flowing through the heat transfer medium channel 112 is selected from the group consisting of, for example, water, brine, and air. Brine is a liquid with a freezing point of 0°C or lower.

[0025] The refrigeration system 100 further includes a control unit 105. As shown in Figure 2, the control unit 105 controls the operation of each element constituting the heat source side circuit 101 and the utilization side circuit 102. Here, a processor is given as an example of the control unit 105. The processor consists of various computing devices such as a CPU (Central Processing Unit), DSP (Digital Signal Processor), FPGA (Field-Programmable Gate Array), and GPU (Graphics Processing Unit). The processor reads various programs of the device into memory and executes them. The processor loads the programs stored in memory into the working area of ​​the memory and executes them, and by controlling each component through the execution of the programs, it realizes functions that match a predetermined purpose.

[0026] (1-1) Heat source side circuit 101 The heat source circuit 101 constitutes a refrigeration cycle that functions as a heat pump utilizing the heat (warmth or cold) generated when the refrigerant is adsorbed or desorbed from the adsorbent. The adsorbent is a powder of an adsorbent material.

[0027] The heat source circuit 101 includes a compressor 131, a first adsorbent 121, a second adsorbent 122, a switching mechanism 135, a bypass flow path 211, and a bypass valve 212. The refrigerant flow path 111 connects the compressor 131, the first adsorbent 121, the second adsorbent 122, and the switching mechanism 135.

[0028] The compressor 131 compresses the refrigerant flowing through the refrigerant passage 111. The compressor 131 is, for example, a rotary compressor. The compressor 131 has an inverter for controlling the rotational speed of the motor. The compressor 131 draws in low-pressure refrigerant from the refrigerant passage 111, compresses it, and discharges it back into the refrigerant passage 111 as high-pressure refrigerant. Low-pressure refrigerant is the refrigerant in the refrigerant passage 111 before it is compressed by the compressor 131. High-pressure refrigerant is the refrigerant in the refrigerant passage 111 after it has been compressed by the compressor 131. During operation of the compressor 131, the sliding parts of the compressor 131 are supplied with lubricating oil sealed in the refrigerant passage 111. A portion of the lubricating oil is stored at the bottom of the compressor 131's casing.

[0029] The first adsorbent 121 and the second adsorbent 122 have adsorbents that adsorb and desorb refrigerant. In the first adsorbent 121 and the second adsorbent 122, the heat of adsorption or the heat of desorption is recovered in the heat medium flowing through the heat medium channel 112. The heat of adsorption is the warmth generated when the adsorbent adsorbs the refrigerant. The heat of desorption is the coldness generated when the adsorbent desorbs the refrigerant. The generation of warmth means that the temperature of the heat medium rises as the heat medium absorbs heat. The generation of coldness means that the temperature of the heat medium decreases as it absorbs heat from the heat medium. The first adsorbent 121 and the second adsorbent 122 are connected to a switching mechanism 135 in the refrigerant channel 111.

[0030] The switching mechanism 135 switches the flow direction of the refrigerant flowing through the refrigerant passage 111. The switching mechanism 135 is, for example, a four-way switching valve. The switching mechanism 135 is configured to switch the refrigerant passage 111 between a first direction, which is the flow direction shown by the solid line in Figure 1, and a second direction, which is the flow direction shown by the dashed line in Figure 1. When the flow direction of the refrigerant passage 111 is the first direction, the discharge side of the compressor 131 is connected to the first adsorbent 121, and the suction side of the compressor 131 is connected to the second adsorbent 122. When the flow direction of the refrigerant passage 111 is the second direction, the discharge side of the compressor 131 is connected to the second adsorbent 122, and the suction side of the compressor 131 is connected to the first adsorbent 121.

[0031] The bypass channel 211 connects the first adsorbent 121 and the second adsorbent 122 without passing through the compressor 131. Specifically, as shown in Figure 1, the bypass channel 211 connects the channel between the first adsorbent 121 and the switching mechanism 135, and the channel between the second adsorbent 122 and the switching mechanism 135 in the refrigerant channel 111.

[0032] The bypass valve 212 is a valve whose opening degree can be adjusted. The bypass valve 212 is, for example, an electrically operated valve. The bypass valve 212 is installed in the bypass passage 211. Specifically, the bypass valve 212 is attached to the piping through which the refrigerant flows in the bypass passage 211. When the bypass valve 212 is open, the space in the first adsorber 121 where the refrigerant exists communicates with the space in the second adsorber 122 where the refrigerant exists via the bypass passage 211.

[0033] The control unit 105 controls the compressor 131, the switching mechanism 135, and the bypass valve 212. The control unit 105 controls the rotational speed of the compressor 131. The control unit 105 controls the timing for starting the compressor 131 and the timing for stopping the compressor 131. The control unit 105 controls the switching mechanism 135 to switch the flow direction of the refrigerant flow path 111 between the first direction and the second direction. The control unit 105 controls the opening and closing of the bypass valve 212 to allow or block the flow of refrigerant in the bypass flow path 211.

[0034] The control unit 105 controls the switching mechanism 135 and the bypass valve 212 to switch the refrigerant flow path 111 between a first state, a second state, and a third state. The first state is a state in which the first adsorbent 121 is under high pressure and the second adsorbent 122 is under low pressure. In the first state, the flow direction of the refrigerant flow path 111 is the first direction. The second state is a state in which the first adsorbent 121 is under low pressure and the second adsorbent 122 is under high pressure. In the second state, the flow direction of the refrigerant flow path 111 is the second direction. The third state is a state in which the bypass valve 212 is at a first opening and the first adsorbent 121 and the second adsorbent 122 are in communication. The first opening is a value greater than zero. The first opening is less than or equal to the opening when the bypass valve 212 is fully open. In the first and second states, the opening of the bypass valve 212 is zero. In other words, in the first and second states, the first adsorbent 121 and the second adsorbent 122 are not in communication via the bypass flow path 211. In the third state, the flow direction of the refrigerant flow path 111 switches between the first and second directions.

[0035] The control unit 105 repeatedly performs a first cycle operation, sequentially switching the refrigerant flow path 111 in the order of first state, third state, second state, and third state. The control unit 105 continuously drives the compressor 131 while the first cycle operation is being performed. Therefore, while the refrigeration system 100 is operating, the control unit 105 keeps the compressor 131 running without stopping it.

[0036] (1-2) User side circuit 102 The utilization-side circuit 102 functions as a heat transfer means for utilizing the heat generated in the heat source-side circuit 101 via a heat transfer medium. The heat transfer medium flowing through the heat transfer medium channel 112 transfers the heat of adsorption or desorption recovered by the first adsorbent 121 or the second adsorbent 122 to a predetermined location.

[0037] The user-side circuit 102 includes a first adsorbent 121, a second adsorbent 122, a first fluid pump 141, a first heat exchanger 142, a second fluid pump 151, a second heat exchanger 152, and flow path changing sections 156-159. The heat transfer medium flow path 112 connects the first adsorbent 121, the second adsorbent 122, the first fluid pump 141, the first heat exchanger 142, the second fluid pump 151, the second heat exchanger 152, and flow path changing sections 156-159.

[0038] The first fluid pump 141 sends the heat transfer medium to the first heat exchanger 142. The first heat exchanger 142 performs heat exchange between the heat transfer medium and air. The first fan 143 generates an airflow that passes through the first heat exchanger 142 so that heat exchange can take place in the first heat exchanger 142.

[0039] The second fluid pump 151 sends the heat transfer medium to the second heat exchanger 152. The second heat exchanger 152 performs heat exchange between the heat transfer medium and air. The second fan 153 generates an airflow that passes through the second heat exchanger 152 so that heat exchange can take place in the second heat exchanger 152.

[0040] The flow path changing units 156-159 switch the connection mode of the heat transfer medium flow path 112 to change the flow path through which the heat transfer medium flows. The flow path changing units 156-159 are, for example, three-way switching valves. The flow path changing units 156-159 are configured to allow the heat transfer medium flow path 112 to switch between a first mode, shown by the solid line in Figure 1, and a second mode, shown by the dashed line in Figure 1.

[0041] The heat transfer fluid channel 112 has two independent channels, a first circulation channel and a second circulation channel, in each of the first and second modes. The heat transfer fluid circulates through each of the first and second circulation channels. In Figure 1, the flow direction of the heat transfer fluid in the first mode is shown by a solid line, and the flow direction of the heat transfer fluid in the second mode is shown by a dashed line.

[0042] In the first mode, the first circulation path connects the first fluid pump 141, the first heat exchanger 142, the flow path changing section 156, the first adsorbent 121, and the flow path changing section 157. In the first mode, the second circulation path connects the second fluid pump 151, the second heat exchanger 152, the flow path changing section 158, the second adsorbent 122, and the flow path changing section 159.

[0043] In the second mode, the first circulation path connects the first fluid pump 141, the first heat exchanger 142, the flow path changing section 156, the second adsorbent 122, and the flow path changing section 157. In the second mode, the second circulation path connects the second fluid pump 151, the second heat exchanger 152, the flow path changing section 158, the first adsorbent 121, and the flow path changing section 159.

[0044] The control unit 105 controls the first fluid pump 141, the first fan 143, the second fluid pump 151, the second fan 153, and the flow path changing units 156-159. The control unit 105 controls the capacity of the first fluid pump 141 and the second fluid pump 151. The control unit 105 controls the rotation speed of the first fan 143 and the second fan 153. The control unit 105 controls the flow path changing units 156-159 to switch the heat transfer medium flow path 112 between the first mode and the second mode.

[0045] (1-3) First adsorbent 121 and second adsorbent 122 The first adsorbent 121 and the second adsorbent 122 each comprise a heat recovery member, an adsorbent, and a casing. The first adsorbent 121 and the second adsorbent 122 each have a first space through which a refrigerant flows and a second space through which a heat transfer medium flows. The first space is part of the refrigerant flow path 111. The second space is part of the heat transfer medium flow path 112. The first space and the second space do not communicate with each other.

[0046] The heat recovery component separates the first space from the second space. The adsorbent is provided in the first space. The adsorbent adsorbs and desorbs the refrigerant in the first space in response to changes in the refrigerant pressure in the first space. The adsorbent is supported on the first surface, which is the surface of the heat recovery component.

[0047] The adsorbent supported on the first surface includes a metal-organic framework (MOF) containing metal ions and organic ligands. A 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, the organic ligands bind to the metal ions, resulting in a polymeric structure with countless openings inside. The opening diameter and topology of a metal-organic framework can be adjusted by selectively combining metal ions and organic ligands. Therefore, by selecting and combining metal ions and organic ligands, the opening diameter of a metal-organic framework can be adjusted, and it can selectively adsorb target substances. Metal-organic frameworks are used, for example, as porous materials that have the function of selective storage and separation of molecules and ions.

[0048] In the refrigeration system 100, a metal-organic structure is used as an adsorbent for adsorbing and desorbing the refrigerant flowing through the refrigerant channel 111. Examples of metal-organic structures include MOF-5, MOF-200, UiO-66, and MIL-101. The adsorbent used in the refrigeration system 100 is, for example, a powder of the metal-organic structure or a molded article of the metal-organic structure. In this case, the adsorbent is supported on the first surface by adhering a mixture of the adsorbent and a binder to the first surface. Examples of binders include acrylic resins, polyester resins, polyolefin resins, and polyurethane resins.

[0049] The heat recovery member is of the cross-fin type. As shown in Figure 3, the heat recovery member includes a plurality of fins 161 and a heat transfer tube 162. The heat transfer tube 162 has a plurality of straight sections 162a extending in a straight line and a folded section 162b connecting two straight sections 162a. In Figure 3, the thickness of the heat transfer tube 162 is omitted. The plurality of fins 161 have through holes in their thickness direction through which the straight sections 162a of the heat transfer tube 162 pass. The plurality of fins 161 are arranged around the straight sections 162a of the heat transfer tube 162 so as to be stacked at predetermined intervals along the direction in which the straight sections 162a extend. The first end 162c and the second end 162d of the heat transfer tube 162 are connected to the heat transfer medium flow path 112. The plurality of fins 161 and the heat transfer tube 162 are housed in a casing 163. The casing 163 has an inlet 163a that is connected to the refrigerant flow path 111.

[0050] The refrigerant flowing through the refrigerant channel 111 flows into the casing 163 through the inlet 163a and flows out of the casing 163 through the inlet 163a. ​​The heat transfer medium flowing through the heat transfer medium channel 112 flows into the heat transfer tube 162 through the first end 162c and flows out of the heat transfer tube 162 through the second end 162d.

[0051] As shown in Figure 3, the first space 164a through which the refrigerant flows is the space inside the casing 163 and outside the heat transfer tubes 162. The second space 164b through which the heat transfer medium flows is the space inside the casing 163 and inside the heat transfer tubes 162. The first surface 182 on which the adsorbent 181 on which the refrigerant is adsorbed and desorbed is supported includes at least a portion of the outer surfaces of the multiple fins 161 and the heat transfer tubes 162. The first surface 182 is, for example, the surfaces of the multiple fins 161 and the outer surfaces of the heat transfer tubes 162. The first surface 182 is in contact with the first space 164a. Therefore, the refrigerant in the first space 164a is in contact with the adsorbent 181 supported on the first surface 182.

[0052] The adsorbent 181 adsorbs the refrigerant in the first space 164a when the pressure of the refrigerant in the first space 164a is equal to or greater than the adsorption pressure. The adsorbent 181 desorbs the refrigerant in the first space 164a when the pressure of the refrigerant in the first space 164a is equal to or less than the desorption pressure. The adsorption pressure is the minimum pressure range in which the adsorbent 181 can adsorb the refrigerant at the temperature of the first space 164a. The desorption pressure is the maximum pressure range in which the adsorbent 181 can desorb the refrigerant at the temperature of the first space 164a. The adsorption pressure and desorption pressure vary depending on the type of adsorbent 181 and the refrigerant.

[0053] (2) Operation of the refrigeration unit 100 The operation of the refrigeration system 100 will be described in the case where the refrigeration system 100 is an air conditioning system. In this case, the first heat exchanger 142 is an indoor heat exchanger, and the second heat exchanger 152 is an outdoor heat exchanger.

[0054] The adsorbents 181 of the first adsorbent 121 and the second adsorbent 122 adsorb and desorb the refrigerant in the refrigerant flow path 111. The adsorbent 181 adsorbs refrigerant when it is in contact with refrigerant in the first space 164a whose pressure is equal to or greater than the adsorption pressure. The adsorbent 181 desorbs refrigerant when it is in contact with refrigerant in the first space 164a whose pressure is equal to or less than the desorption pressure.

[0055] When the refrigerant flow path 111 is in the first state, it is possible to create a high-pressure state inside the first adsorbent 121 and a low-pressure state inside the second adsorbent 122. When the first adsorbent 121 is in a high-pressure state, the adsorbent material 181 of the first adsorbent 121 is in contact with the high-pressure refrigerant in the first space 164a. When the second adsorbent 122 is in a low-pressure state, the adsorbent material 181 of the second adsorbent 122 is in contact with the low-pressure refrigerant in the first space 164a.

[0056] When the refrigerant flow path 111 is in the second state, it is possible to create a low-pressure state inside the first adsorbent 121 and a high-pressure state inside the second adsorbent 122. When the first adsorbent 121 is in a low-pressure state, the adsorbent material 181 of the first adsorbent 121 is in contact with the low-pressure refrigerant in the first space 164a. When the second adsorbent 122 is in a high-pressure state, the adsorbent material 181 of the second adsorbent 122 is in contact with the high-pressure refrigerant in the first space 164a.

[0057] This section describes the change in the adsorption amount, which is the amount of refrigerant adsorbed on the adsorbent material 181, when the refrigerant flow path 111 is in the first state. When the control unit 105 switches the refrigerant flow path 111 from the second state to the first state via the third state, the adsorption amount of the adsorbent material 181 of the first adsorber 121 is the first adsorption amount, and the adsorption amount of the adsorbent material 181 of the second adsorber 122 is the second adsorption amount. The second adsorption amount is greater than the first adsorption amount. The second adsorption amount is the maximum amount of refrigerant that the adsorbent material 181 can adsorb. The second adsorption amount includes not only the theoretical maximum amount, but also an amount that can change depending on the high pressure or the time the high pressure state is maintained. The pressure of the high-pressure refrigerant is greater than or equal to the adsorption pressure, and the pressure of the low-pressure refrigerant is less than or equal to the desorption pressure.

[0058] When the refrigerant flow path 111 is in the first state, the adsorbent 181 of the first adsorbent 121 is in contact with the high-pressure refrigerant, and the adsorbent 181 of the second adsorbent 122 is in contact with the low-pressure refrigerant. In the first adsorbent 121, the adsorbent 181 gradually adsorbs the refrigerant, and in the process, the adsorbent 181 releases heat. In the second adsorbent 122, the adsorbent 181 gradually desorbs the refrigerant, and in the process, the adsorbent 181 absorbs heat. Therefore, the amount of adsorbent 181 in the first adsorbent 121 increases from the first adsorption amount to the second adsorption amount, and the amount of adsorbent 181 in the second adsorbent 122 decreases from the second adsorption amount to the first adsorption amount.

[0059] The change in the amount of refrigerant adsorbed on the adsorbent material 181 when the refrigerant flow path 111 is in the second state will be explained. When the control unit 105 switches the refrigerant flow path 111 from the first state to the second state via the third state, the amount of adsorbent on the adsorbent material 181 of the first adsorber 121 is the second adsorbent amount, and the amount of adsorbent on the adsorbent material 181 of the second adsorber 122 is the first adsorbent amount.

[0060] When the refrigerant flow path 111 is in the second state, the adsorbent 181 of the first adsorbent 121 is in contact with the low-pressure refrigerant, and the adsorbent 181 of the second adsorbent 122 is in contact with the high-pressure refrigerant. In the first adsorbent 121, the adsorbent 181 gradually desorbs the refrigerant, and in the process, the adsorbent 181 absorbs heat. In the second adsorbent 122, the adsorbent 181 gradually adsorbs the refrigerant, and in the process, the adsorbent 181 releases heat. Therefore, the amount of adsorbent 181 in the first adsorbent 121 decreases from the second adsorption amount to the first adsorption amount, and the amount of adsorbent 181 in the second adsorbent 122 increases from the first adsorption amount to the second adsorption amount.

[0061] When the refrigerant flow path 111 is in the first state and the heat transfer fluid flow path 112 is in the first mode, the heat generated in the first adsorbent 121 during the process of the adsorbent 181 adsorbing the refrigerant in the first space 164a is recovered into the heat transfer fluid in the second space 164b. On the other hand, in the second adsorbent 122, the cold energy generated in the process of the adsorbent 181 desorbing the refrigerant adsorbed on it is recovered into the heat transfer fluid in the second space 164b. Therefore, in the first adsorbent 121, heat is recovered into the heat transfer fluid flowing through the first circulation flow path, and in the second adsorbent 122, cold energy is recovered into the heat transfer fluid flowing through the second circulation flow path.

[0062] Subsequently, when the amount of adsorption by the adsorbent material 181 of the first adsorber 121 reaches the second adsorption amount, the adsorbent material 181 of the first adsorber 121 becomes less able to adsorb refrigerant. When this state is reached, the control unit 105 switches the refrigerant flow path 111 from the first state to the third state and then to the second state, and also switches the heat transfer medium flow path 112 from the first mode to the second mode.

[0063] When the refrigerant flow path 111 is in the second state and the heat transfer fluid flow path 112 is in the second mode, the heat generated in the second adsorbent 122 during the process of the adsorbent 181 adsorbing the refrigerant in the first space 164a is recovered into the heat transfer fluid in the second space 164b. On the other hand, in the first adsorbent 121, the cold energy generated during the process of the adsorbent 181 desorbing the refrigerant adsorbed on it is recovered into the heat transfer fluid in the second space 164b. Therefore, in the first adsorbent 121, cold energy is recovered into the heat transfer fluid flowing through the second circulation flow path, and in the second adsorbent 122, heat energy is recovered into the heat transfer fluid flowing through the first circulation flow path.

[0064] Subsequently, when the amount of adsorption by the adsorbent material 181 of the second adsorbent 122 reaches the second adsorption amount, the adsorbent material 181 of the second adsorbent 122 becomes less able to adsorb refrigerant. When this state is reached, the control unit 105 switches the refrigerant flow path 111 from the second state to the third state and then to the first state, and also switches the heat transfer medium flow path 112 from the second mode to the first mode.

[0065] As described above, by the refrigerant flow path 111 alternately transitioning between the first state and the second state via the third state, the refrigerant can be continuously adsorbed or desorbed onto the adsorbent material 181 in either the first adsorbent material 121 or the second adsorbent material 122. By alternately switching the heat transfer medium flow path 112 between the first mode and the second mode in conjunction with the switching of the refrigerant flow path 111 to the first to third states, the heat generated when the adsorbent material 181 adsorbs the refrigerant can be continuously recovered by the heat transfer medium flowing through the first circulation flow path.

[0066] Furthermore, when the refrigerant flow path 111 is in the first state and the heat transfer fluid flow path 112 is in the second mode, heat is recovered in the heat transfer fluid flowing through the second circulation path in the first adsorbent 121, and cold energy is recovered in the heat transfer fluid flowing through the first circulation path in the second adsorbent 122. When the refrigerant flow path 111 is in the second state and the heat transfer fluid flow path 112 is in the first mode, cold energy is recovered in the heat transfer fluid flowing through the first circulation path in the first adsorbent 121, and heat is recovered in the heat transfer fluid flowing through the second circulation path in the second adsorbent 122. Therefore, by switching the heat transfer fluid flow path 112 alternately between the second mode and the first mode in accordance with the switching of the refrigerant flow path 111 to the first to third states, the cold energy generated when the adsorbent 181 desorbs the refrigerant can be continuously recovered by the heat transfer fluid flowing through the first circulation path.

[0067] Therefore, the refrigeration device 100 can continuously supply the first heat exchanger 142, which is connected to the first circulation channel, with a heat transfer medium heated by the recovered thermal energy, or a heat transfer medium cooled by the recovered cold energy. The air that has exchanged heat with the heat transfer medium in the first heat exchanger 142 is sent to a predetermined location by the first fan 143.

[0068] (3) Control of the refrigeration unit 100 Figure 4 is a control time chart for the refrigeration system 100 of this embodiment. The time chart in Figure 4(a) shows the state of the compressor 131. "Operating" in Figure 4(a) shows the state in which the compressor 131 is running. "Stopped" in Figure 4(a) shows the state in which the compressor 131 is stopped. The time chart in Figure 4(b) shows the opening degree of the bypass valve 212. "Zero" in Figure 4(b) shows the state in which the opening degree of the bypass valve 212 is zero and the bypass valve 212 is closed. "First opening degree" in Figure 4(b) shows the state in which the opening degree of the bypass valve 212 is a first opening degree greater than zero and the bypass valve 212 is open. The time chart in Figure 4(c) shows the state of the switching mechanism 135. "First direction" in Figure 4(c) shows the state in which the flow direction of the refrigerant flow path 111 is the first direction. In Figure 4(c), "Second Direction" indicates the state where the flow direction of the refrigerant flow path 111 is the second direction. The time chart in Figure 4(d) shows the change in refrigerant pressure in the first space 164a of the first adsorbent 121. The time chart in Figure 4(e) shows the change in refrigerant pressure in the first space 164a of the second adsorbent 122. In Figures 4(d) and (e), "Adsorption Setting Pressure" is a predetermined target pressure that is greater than or equal to the adsorption pressure. In Figures 4(d) and (e), "Desorption Setting Pressure" is a predetermined target pressure that is less than or equal to the desorption pressure. Hereafter, as necessary, the refrigerant pressure in the first space 164a of the first adsorbent 121 will be described as "Pressure in the First Adsorbent 121," and the refrigerant pressure in the first space 164a of the second adsorbent 122 will be described as "Pressure in the Second Adsorbent 122."

[0069] As shown in Figure 4, the control unit 105 repeatedly performs a first cycle operation in which the refrigerant flow path 111 is sequentially switched in the order of first state, third state, second state, and third state. When the control unit 105 transitions from the first or second state to the third state, it raises the opening of the bypass valve 212 from zero to the first opening. When the control unit 105 transitions from the third state to the first or second state, it lowers the opening of the bypass valve 212 from the first opening to zero. Therefore, in the third state, the first adsorbent 121 and the second adsorbent 122 are in communication via the bypass flow path 211. In the third state following the first state, the control unit 105 controls the switching mechanism 135 to switch the flow direction of the refrigerant flow path 111 from the first direction to the second direction. In the third state following the second state, the control unit 105 controls the switching mechanism 135 to switch the flow direction of the refrigerant flow path 111 from the second direction to the first direction.

[0070] (4) Features As shown in Figure 4, when the refrigerant flow path 111 is in the first state, the pressure in the first adsorbent 121 increases and the pressure in the second adsorbent 122 decreases. In the first state, the pressure in the first adsorbent 121 approaches the adsorption setting pressure, and the pressure in the second adsorbent 122 approaches the desorption setting pressure. When the pressure in the first adsorbent 121 reaches a predetermined pressure below the adsorption setting pressure, or when the pressure in the second adsorbent 122 reaches a predetermined pressure above the desorption setting pressure, the control unit 105 increases the opening of the bypass valve 212 from zero to the first opening. As a result, the refrigerant flow path 111 transitions from the first state to the third state. In the third state, the first adsorbent 121 and the second adsorbent 122 are in communication via the bypass flow path 211. Therefore, in the third state after the first state, the increase in pressure in the first adsorbent 121 and the decrease in pressure in the second adsorbent 122 are suppressed without stopping the compressor 131.

[0071] As shown in Figure 4, when the refrigerant flow path 111 is in the second state, the pressure in the first adsorbent 121 decreases and the pressure in the second adsorbent 122 increases. In the second state, the pressure in the first adsorbent 121 approaches the desorption setting pressure, and the pressure in the second adsorbent 122 approaches the adsorption setting pressure. When the pressure in the first adsorbent 121 reaches a predetermined pressure that is above the desorption setting pressure, or when the pressure in the second adsorbent 122 reaches a predetermined pressure that is below the adsorption setting pressure, the control unit 105 increases the opening of the bypass valve 212 from zero to the first opening. As a result, the refrigerant flow path 111 transitions from the second state to the third state. In the third state, the first adsorbent 121 and the second adsorbent 122 are in communication via the bypass flow path 211. Therefore, in the third state after the second state, the decrease in pressure in the first adsorbent 121 and the increase in pressure in the second adsorbent 122 are suppressed without stopping the compressor 131.

[0072] As a result, the refrigeration system 100 can continuously drive the compressor 131 while maintaining the pressure in the first adsorbent 121 and the second adsorbent 122 at a predetermined value or range during the execution of the first cycle operation by setting the opening of the bypass valve 212 to the first opening while the refrigerant flow path 111 is in the third state. If the compressor 131 is stopped each time the refrigerant flow path 111 is switched between the first and second states, the compressor 131 will be repeatedly started and stopped during the operation of the refrigeration system 100, which may reduce the reliability of the compressor 131. Therefore, the refrigeration system 100 can suppress the reduction in the reliability of the compressor 131 by having the control unit 105 repeatedly execute the first cycle operation in which the refrigerant flow path 111 is sequentially switched in the order of first state, third state, second state, and third state.

[0073] —Second Embodiment— The basic configuration and operation of the refrigeration system 100 of the second embodiment are the same as those of the refrigeration system 100 of the first embodiment. The main difference between the refrigeration system 100 of the second embodiment and the refrigeration system 100 of the first embodiment is the control by the control unit 105.

[0074] (1) Control of the refrigeration unit 100 In this embodiment, the control unit 105 changes the opening degree of the bypass valve 212 in the third state during the execution of the first cycle operation, similar to the first embodiment. The control unit 105 also changes the rotational speed of the compressor 131 during the execution of the first cycle operation.

[0075] Figure 5 is a control time chart for the refrigeration system 100 of this embodiment. The time chart in Figure 5(a) represents the rotational speed of the compressor 131. The "set value" in Figure 5(a) is the set value for the rotational speed of the compressor 131 during normal operation of the refrigeration system 100. The "lower limit" in Figure 5(a) is the lower limit for the rotational speed of the compressor 131 during normal operation of the refrigeration system 100. The "lower limit" is greater than zero. During the execution of the first cycle operation, the control unit 105 changes the rotational speed of the compressor 131 within the range from the "lower limit" to the "set value". Therefore, as in the first embodiment, the control unit 105 continues to operate the compressor 131 without stopping it while the refrigeration system 100 is operating. The time charts in Figures 5(b) to 5(e) correspond to the time charts in Figures 4(b) to 5(e), respectively.

[0076] As shown in Figure 5(a), the control unit 105 reduces the rotational speed of the compressor 131 while the refrigerant flow path 111 is in the first or second state. Specifically, the control unit 105 makes the average rotational speed of the compressor 131 in the first period P1 higher than the average rotational speed of the compressor 131 in the second period P2, which is after the first period P1. The first period P1 is the initial period of the first and second states. In other words, the first period P1 is the period that includes the time when the first or second state begins. The second period P2 is the final period of the first and second states. In other words, the second period P2 is the period that includes the time when the first or second state ends. The start of the second period P2 is after the end of the first period P1. The average rotational speed is the average of the rotational speeds over a predetermined period. In Figure 5(a), the first period P1 is the period during which the average rotational speed of the compressor 131 is at a set value, and the second period P2 is the period during which the average rotational speed of the compressor 131 is at a lower limit. The period from the end of the first period P1 to the start of the second period P2 is the period during which the rotational speed of the compressor 131 decreases. During the period during which the rotational speed of the compressor 131 decreases, the control unit 105 may monotonically decrease the rotational speed of the compressor 131, or it may decrease the rotational speed of the compressor 131 while increasing or maintaining it.

[0077] The control unit 105 reduces the rotational speed of the compressor 131 when the pressure in the first adsorbent 121 or the second adsorbent 122 reaches a predetermined value while the refrigerant flow path 111 is in the first or second state. As shown in Figure 5, in the first state, when the pressure in the first adsorbent 121 reaches a predetermined first pressure that is higher than the desorption setting pressure and lower than the adsorption setting pressure, the control unit 105 reduces the rotational speed of the compressor 131. This reduces the change in pressure in the first adsorbent 121. Subsequently, when the pressure in the first adsorbent 121 reaches a predetermined third pressure that is lower than the adsorption setting pressure and higher than the first pressure, the control unit 105 maintains the rotational speed of the compressor 131 at the lower limit. Also, in the second state, when the pressure in the first adsorbent 121 reaches a predetermined second pressure that is higher than the desorption setting pressure and lower than the adsorption setting pressure, the control unit 105 reduces the rotational speed of the compressor 131. This reduces the change in pressure in the first adsorbent 121. Subsequently, when the pressure inside the first adsorber 121 reaches a predetermined fourth pressure that is higher than the desorption setting pressure and lower than the second pressure, the control unit 105 maintains the rotational speed of the compressor 131 at its lower limit.

[0078] The control unit 105 sets the average rotational speed of the compressor 131 higher when the refrigerant flow path 111 is in the first or second state than when the refrigerant flow path 111 is in the third state. In Figure 5, the rotational speed of the compressor 131 when the refrigerant flow path 111 is in the third state is the lower limit. When the refrigerant flow path 111 transitions from the third state to the first or second state and the first period P1 begins, the control unit 105 increases the rotational speed of the compressor 131 from the lower limit to the set value, as shown in Figure 5.

[0079] The control unit 105 performs control to reduce the rotational speed of the compressor 131 so that the pressure in the first adsorbent 121 increases and the pressure in the second adsorbent 122 decreases while the refrigerant flow path 111 is in the first state. The control unit 105 performs control to reduce the rotational speed of the compressor 131 so that the pressure in the second adsorbent 122 increases and the pressure in the first adsorbent 121 decreases while the refrigerant flow path 111 is in the second state.

[0080] (2) Characteristics As shown in Figure 5, when the refrigerant flow path 111 is in the first state, the pressure in the first adsorbent 121 increases and the pressure in the second adsorbent 122 decreases. In the first state, after the start of the first period P1, when the pressure in the first adsorbent 121 reaches a predetermined first pressure lower than the adsorption setting pressure, or when the pressure in the second adsorbent 122 reaches a predetermined second pressure higher than the desorption setting pressure, the first period P1 ends, and the control unit 105 reduces the rotational speed of the compressor 131. As a result, the rate of increase in the pressure in the first adsorbent 121 and the rate of decrease in the pressure in the second adsorbent 122 become smaller. Subsequently, when the pressure in the first adsorbent 121 reaches a predetermined third pressure lower than the adsorption setting pressure and higher than the first pressure, or when the pressure in the second adsorbent 122 reaches a predetermined fourth pressure higher than the desorption setting pressure and lower than the second pressure, the rotational speed of the compressor 131 reaches its lower limit and the second period P2 begins. As a result, the rate of increase in pressure in the first adsorbent 121 and the rate of decrease in pressure in the second adsorbent 122 are further reduced. During the second period P2, the control unit 105 maintains the rotational speed of the compressor 131 at the lower limit. During the second period P2, the pressure in the first adsorbent 121 approaches the adsorption set pressure, and the pressure in the second adsorbent 122 approaches the desorption set pressure. When the second period P2 ends, the system transitions from the first state to the third state. Therefore, in the first state and the subsequent third state, the increase in pressure in the first adsorbent 121 and the decrease in pressure in the second adsorbent 122 are suppressed without stopping the compressor 131.

[0081] As shown in Figure 5, when the refrigerant flow path 111 is in the second state, the pressure in the first adsorbent 121 decreases and the pressure in the second adsorbent 122 increases. In the second state, after the start of the first period P1, when the pressure in the first adsorbent 121 reaches the second pressure, or the pressure in the second adsorbent 122 reaches the first pressure, the first period P1 ends, and the control unit 105 reduces the rotational speed of the compressor 131. As a result, the rate of decrease in the pressure in the first adsorbent 121 and the rate of increase in the pressure in the second adsorbent 122 become smaller. Subsequently, when the pressure in the first adsorbent 121 reaches the fourth pressure, or the pressure in the second adsorbent 122 reaches the third pressure, the rotational speed of the compressor 131 reaches its lower limit and the second period P2 begins. As a result, the rate of decrease in the pressure in the first adsorbent 121 and the rate of increase in the pressure in the second adsorbent 122 become even smaller. During the second period P2, the control unit 105 maintains the rotational speed of the compressor 131 at a lower limit. During the second period P2, the pressure in the first adsorbent 121 approaches the desorption setting pressure, and the pressure in the second adsorbent 122 approaches the adsorption setting pressure. When the second period P2 ends, the system transitions from the second state to the third state. Therefore, in the second state and the subsequent third state, the decrease in pressure in the first adsorbent 121 and the increase in pressure in the second adsorbent 122 are suppressed without stopping the compressor 131.

[0082] As a result, the refrigeration system 100 can continuously drive the compressor 131 while maintaining the pressure in the first adsorber 121 and the second adsorber 122 at a predetermined value or range during the execution of the first cycle operation by reducing the rotational speed of the compressor 131 while the refrigerant flow path 111 is in the first or second state. Therefore, the refrigeration system 100 can suppress a decrease in the reliability of the compressor 131, similar to the first embodiment.

[0083] —Third Embodiment— The basic configuration and operation of the refrigeration system 100 of the third embodiment are the same as those of the refrigeration system 100 of the second embodiment. The main difference between the refrigeration system 100 of the third embodiment and the refrigeration system 100 of the second embodiment is the control by the control unit 105.

[0084] (1) Control of the refrigeration unit 100 In this embodiment, during the execution of the first cycle operation, the control unit 105 changes the opening degree of the bypass valve 212 in the third state and changes the rotational speed of the compressor 131, similar to the second embodiment. Furthermore, during the execution of the first cycle operation, the control unit 105 also changes the opening degree of the bypass valve 212 in the first and second states.

[0085] Figure 6 is a control time chart for the refrigeration system 100 of this embodiment. The time charts in Figures 6(a) to 6(e) correspond to the time charts in Figures 5(a) to 5(e), respectively.

[0086] As shown in Figure 6(a), the control unit 105 performs a first control to reduce the rotational speed of the compressor 131 while the refrigerant flow path 111 is in the first or second state. As shown in Figure 6(b), the control unit 105 performs a second control to increase the opening degree of the bypass valve 212 from zero while the refrigerant flow path 111 is in the first or second state. The control unit 105 starts the second control after starting the first control. In Figure 6, the control unit 105 starts the first control at the end of the first period P1 and starts the second control at the start of the second period P2. When the second control is executed, the control unit 105 increases the opening degree of the bypass valve 212 from zero to a second opening degree which is smaller than the first opening degree. Therefore, as shown in Figure 6(b), the opening degree of the bypass valve 212 while the refrigerant flow path 111 is in the third state is higher than the opening degree of the bypass valve 212 at the end of the second period P2.

[0087] The control unit 105 performs a first control to reduce the rotational speed of the compressor 131 when the pressure in the first adsorbent 121 or the second adsorbent 122 reaches a predetermined value while the refrigerant flow path 111 is in a first or second state. As shown in Figure 6, in the first state, when the pressure in the first adsorbent 121 reaches a predetermined pressure that is higher than the desorption setting pressure and lower than the adsorption setting pressure, the control unit 105 starts the first control. This reduces the change in pressure in the first adsorbent 121. Subsequently, when the pressure in the first adsorbent 121 reaches the adsorption setting pressure, the control unit 105 maintains the rotational speed of the compressor 131 at the lower limit. Also, in the second state, when the pressure in the first adsorbent 121 reaches a predetermined pressure that is higher than the desorption setting pressure and lower than the adsorption setting pressure, the control unit 105 starts the first control. This reduces the change in pressure in the first adsorbent 121. Subsequently, when the pressure inside the first adsorber 121 reaches the desorption set pressure, the control unit 105 maintains the rotational speed of the compressor 131 at the lower limit.

[0088] The control unit 105 may start the second control when the pressure in the first adsorbent 121 or the second adsorbent 122 reaches a predetermined value. For example, while the refrigerant flow path 111 is in the first state, the control unit 105 starts the second control when the pressure in the first adsorbent 121 rises to a predetermined pressure below the adsorption setting pressure, or when the pressure in the second adsorbent 122 falls to a predetermined pressure above the desorption setting pressure. Alternatively, while the refrigerant flow path 111 is in the second state, the control unit 105 starts the second control when the pressure in the first adsorbent 121 falls to a predetermined pressure above the desorption setting pressure, or when the pressure in the second adsorbent 122 rises to a predetermined pressure below the adsorption setting pressure.

[0089] The control unit 105 may start the second control after the rotational speed of the compressor 131 has decreased to a predetermined value during the execution of the first control. For example, as shown in Figure 6, the control unit 105 starts the second control when the rotational speed of the compressor 131 reaches a lower limit in the first or second state.

[0090] Figure 7 is a flowchart of the control by the control unit 105 when the refrigerant flow path 111 is in the first and second states. Figure 8 is a flowchart of the control by the control unit 105 when the refrigerant flow path 111 is in the third state. While the control unit 105 is performing the first cycle operation, the "end" step in Figure 7 means transitioning to the "start" step in Figure 8, and the "end" step in Figure 8 means transitioning to the "start" step in Figure 7.

[0091] When the refrigerant flow path 111 is in the first state or the second state, the control unit 105 executes the processes in steps S11 to S16 of Figure 7.

[0092] In step S11, the control unit 105 sets the rotational speed of the compressor 131 to a set value. Then, the process proceeds to step S12.

[0093] In step S12, the control unit 105 determines whether the pressure in the first adsorbent 121 has reached the adsorption setting pressure, or whether the pressure in the second adsorbent 122 has reached the desorption setting pressure, if the refrigerant flow path 111 is in the first state. If the refrigerant flow path 111 is in the second state, the control unit 105 determines whether the pressure in the first adsorbent 121 has reached the desorption setting pressure, or whether the pressure in the second adsorbent 122 has reached the adsorption setting pressure. If it is determined that the pressure in the first adsorbent 121 or the second adsorbent 122 has reached the adsorption setting pressure or the desorption setting pressure, the process proceeds to step S13. If it is not determined that the pressure has reached the set2 again after a predetermined period of time has elapsed.

[0094] In step S13, the control unit 105 determines whether it is time to switch the flow direction of the refrigerant flow path 111 by the switching mechanism 135. If it is determined that it is time to switch the flow direction of the refrigerant flow path 111, the system proceeds to the "Start" step in Figure 8; otherwise, it proceeds to step S14.

[0095] In step S14, the control unit 105 determines whether the rotational speed of the compressor 131 is at the lower limit. If it is determined that the rotational speed of the compressor 131 is at the lower limit, the process proceeds to step S15; otherwise, the process proceeds to step S16.

[0096] In step S15, the control unit 105 increases the opening degree of the bypass valve 212 from zero to the second opening degree. Then, the process proceeds to step S12.

[0097] In step S16, the control unit 105 reduces the rotational speed of the compressor 131. Then, the process proceeds to step S12.

[0098] When the refrigerant flow path 111 is in the third state, the control unit 105 executes the processes in steps S21 to S24 of Figure 8.

[0099] In step S21, the control unit 105 increases the opening degree of the bypass valve 212 from the second opening degree to the first opening degree. Then, the process proceeds to step S22.

[0100] In step S22, the control unit 105 determines whether the pressure in the first adsorbent 121 and the second adsorbent 122 has been equalized. Specifically, the control unit 105 determines whether the difference between the pressure in the first adsorbent 121 and the pressure in the second adsorbent 122 is less than or equal to a predetermined value. If it is determined that the pressure has been equalized, the process proceeds to step S23; otherwise, the process proceeds to step S24.

[0101] In step S23, the control unit 105 switches the flow direction of the refrigerant flow path 111 using the switching mechanism 135. Then, the process proceeds to step S24.

[0102] In step S24, the control unit 105 reduces the opening of the bypass valve 212 to zero. Then, the process proceeds to the "Start" step in Figure 7.

[0103] (2) Characteristics As shown in Figure 6, when the refrigerant flow path 111 is in the first state, the pressure in the first adsorbent 121 increases and the pressure in the second adsorbent 122 decreases. In the first state, when the rotational speed of the compressor 131 reaches its lower limit, the control unit 105 increases the opening of the bypass valve 212 from zero to the second opening. As a result, in the first state, the first adsorbent 121 and the second adsorbent 122 are in communication via the bypass flow path 211. Therefore, in the first state and the subsequent third state, the increase in pressure in the first adsorbent 121 and the decrease in pressure in the second adsorbent 122 are suppressed without stopping the compressor 131.

[0104] As shown in Figure 6, when the refrigerant flow path 111 is in the second state, the pressure in the first adsorbent 121 decreases and the pressure in the second adsorbent 122 increases. In the second state, when the rotational speed of the compressor 131 reaches its lower limit, the control unit 105 increases the opening of the bypass valve 212 from zero to the second opening. As a result, in the second state, the first adsorbent 121 and the second adsorbent 122 are in communication via the bypass flow path 211. Therefore, in the second state and the subsequent third state, the decrease in pressure in the first adsorbent 121 and the increase in pressure in the second adsorbent 122 are suppressed without stopping the compressor 131.

[0105] As a result, the refrigeration system 100 can continuously drive the compressor 131 while maintaining the pressure in the first adsorber 121 and the second adsorber 122 at a predetermined value or range during the execution of the first cycle operation by increasing the opening of the bypass valve 212 from zero to the second opening while the refrigerant flow path 111 is in the first or second state. Therefore, the refrigeration system 100 can suppress a decrease in the reliability of the compressor 131, similar to the first embodiment.

[0106] Furthermore, the refrigeration system 100 can accommodate multiple adsorption setting pressures and multiple desorption setting pressures by appropriately setting the lower limit of the rotational speed of the compressor 131 and the second opening degree of the bypass valve 212. Therefore, the refrigeration system 100 can perform control based on a predetermined capacity while maintaining the reliability of the compressor 131.

[0107] —Revised Version— (1) Variation A In the first to third embodiments, the bypass passage 211 connects the passage between the first adsorbent 121 and the switching mechanism 135 and the passage between the second adsorbent 122 and the switching mechanism 135 in the refrigerant passage 111. However, the position of the bypass passage 211 is not limited as long as the bypass passage 211 connects the first adsorbent 121 and the second adsorbent 122 without passing through the compressor 131.

[0108] The bypass channel 211 may directly connect the first adsorbent 121 and the second adsorbent 122 in the refrigerant channel 111. In this case, the piping through which the refrigerant flows in the bypass channel 211 is connected to the casings 163 of the first adsorbent 121 and the second adsorbent 122. The bypass channel 211 is connected to the first space 164a of the first adsorbent 121 and the first space 164a of the second adsorbent 122.

[0109] The bypass passage 211 may connect the passage between the suction side of the compressor 131 and the switching mechanism 135, and the passage between the discharge side of the compressor 131 and the switching mechanism 135, within the refrigerant passage 111. Alternatively, the bypass passage 211 may directly connect the suction side and the discharge side of the compressor 131.

[0110] (2) Modification B In the first to third embodiments, the control unit 105 reduces the opening degree of the bypass valve 212 from the first opening degree to zero when transitioning from the third state to the first or second state. The control unit 105 may reduce the opening degree of the bypass valve 212 to zero simultaneously with the start of the first and second states, or it may reduce the opening degree of the bypass valve 212 to zero after the start of the first and second states. For example, the control unit 105 may reduce the opening degree of the bypass valve 212 to zero during the first period P1 in Figures 5 and 6.

[0111] (3) Variation C In the first to third embodiments, the control unit 105 may control at least one of the opening degree of the bypass valve 212 and the rotational speed of the compressor 131 in accordance with the pressure in the first adsorbent 121 and the second adsorbent 122. In this case, pressure sensors may be provided in the first space 164a of the first adsorbent 121 and the first space 164a of the second adsorbent 122, and the control unit 105 may control at least one of the opening degree of the bypass valve 212 and the rotational speed of the compressor 131 based on the values ​​detected by the pressure sensors.

[0112] (4) Modification D In the third embodiment, the control unit 105 performs a second control to increase the opening degree of the bypass valve 212 from zero after starting a first control to reduce the rotational speed of the compressor 131. The control unit 105 may also perform the first control after starting the second control. For example, the control unit 105 may perform the second control to increase the opening degree of the bypass valve 212 to a third opening degree, which is lower than the second opening degree, then start the first control, and then perform the second control to increase the opening degree of the bypass valve 212 from the third opening degree to the second control.

[0113] (5) Variation E In the first to third embodiments, the casings 163 of the first adsorbent 121 and the second adsorbent 122 have an inlet 163a connected to a refrigerant flow path 111. The refrigerant in the refrigerant flow path 111 flows into the casing 163 through the inlet 163a and flows out from the casing 163 through the inlet 163a. ​​The inlet 163a serves as both an inlet and an outlet for the refrigerant of the first adsorbent 121 and the second adsorbent 122.

[0114] In this modified example, the casing 163 has an inlet and an outlet. In this case, the refrigerant flowing through the refrigerant flow path 111 flows into the interior of the casing 163 through the inlet, and the refrigerant inside the casing 163 flows out from the interior of the casing 163 through the outlet. The inlet functions as the inlet for the refrigerant of the first adsorbent 121 and the second adsorbent 122. The outlet functions as the outlet for the refrigerant of the first adsorbent 121 and the second adsorbent 122.

[0115] (6) Modification F In the first to third embodiments, the adsorbent used in the refrigeration device 100 is a metal-organic structure. However, materials other than metal-organic structures may be used as the adsorbent. Examples of materials other than metal-organic structures include activated carbon, zeolite-based materials, silica-based materials, and alumina-based materials.

[0116] While embodiments of this disclosure have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of this disclosure as described in the claims. [Explanation of Symbols]

[0117] 100: Refrigeration equipment 105: Control Unit 111: Refrigerant flow path 121: 1st adsorption device 122:Second adsorption device 131: Compressor 135: Switching mechanism 181: Adsorbent 211: Bypass channel 212: Bypass valve [Prior art documents] [Patent Documents]

[0118] [Patent Document 1] U.S. Patent Application Publication No. 2023 / 0417459

Claims

1. A refrigerant flow path (111) through which the refrigerant flows, A compressor (131) that inhales low-pressure refrigerant, compresses it, and discharges it as high-pressure refrigerant, A first adsorbent (121) and a second adsorbent (122) are provided, each having an adsorbent (181) that adsorbs and desorbs refrigerant in response to changes in the pressure of the refrigerant, and the heat generated when the adsorbent adsorbs the refrigerant and the cold generated when the adsorbent desorbs the refrigerant are recovered. Switching mechanism (135), A bypass channel (211) connects the first adsorbent and the second adsorbent without passing through the compressor, A bypass valve (212) is provided in the bypass passage and its opening degree can be adjusted, Control unit (105) and Equipped with, The control unit controls the switching mechanism and the bypass valve to switch the refrigerant flow path between a first state, a second state, and a third state. The first state is a state in which the first adsorbent is under high pressure and the second adsorbent is under low pressure. The second state is a state in which the inside of the first adsorbent is in a low-pressure state and the inside of the second adsorbent is in a high-pressure state. The third state is a state in which the bypass valve is at a first opening and the first adsorbent and the second adsorbent are in communication. The control unit repeatedly performs a first cycle operation in which the refrigerant flow path is sequentially switched in the order of the first state, the third state, the second state, and the third state, and continuously drives the compressor during the execution of the first cycle operation. Refrigeration device (100).

2. The control unit changes the rotational speed of the compressor during the execution of the first cycle operation. The refrigeration apparatus according to claim 1.

3. The control unit, while the refrigerant flow path is in the first state or the second state, makes the average rotational speed of the compressor in the first period higher than the average rotational speed of the compressor in the second period which follows the first period. The first period includes the time when the first or second state begins, The second period includes the time when the first or second state ends. The refrigeration apparatus according to claim 2.

4. The control unit reduces the rotational speed of the compressor when the pressure in the first or second adsorbent reaches a predetermined value while the refrigerant flow path is in the first or second state. The refrigeration apparatus according to claim 2 or 3.

5. The control unit makes the average rotational speed of the compressor when the refrigerant flow path is in the first or second state higher than the rotational speed of the compressor when the refrigerant flow path is in the third state. The refrigeration apparatus according to claim 2 or 3.

6. The control unit, During the execution of the first cycle, the opening degree of the bypass valve is changed. While the refrigerant flow path is in the first state or the second state, the opening degree of the bypass valve is set to zero for a predetermined period including the time when the first state or the second state begins. The refrigeration apparatus according to claim 2 or 3.

7. The control unit, A first control, and, while the refrigerant flow path is in the first state or the second state, reduces the rotational speed of the compressor. Second control: While the refrigerant flow path is in the first or second state, the opening degree of the bypass valve is increased from zero. Execute, The control unit starts the second control after the start of the first control. The refrigeration apparatus according to claim 6.

8. The control unit starts the second control when the pressure in the first or second adsorbent reaches a predetermined value. The refrigeration apparatus according to claim 7.

9. The control unit starts the second control after the rotational speed of the compressor has decreased to a first value during the execution of the first control. The refrigeration apparatus according to claim 7.

10. When the second control is executed, the control unit raises the opening degree of the bypass valve from zero to a second opening degree that is smaller than the first opening degree. The refrigeration apparatus according to claim 7.

11. The control unit, While the refrigerant flow path is in the first state, if the pressure in the first adsorbent rises to a second value, or if the pressure in the second adsorbent falls to a third value, the second control is started. While the refrigerant flow path is in the second state, if the pressure in the second adsorbent rises to the second value, or if the pressure in the first adsorbent falls to the third value, the second control is started. The refrigeration apparatus according to claim 7.

12. The control unit, While the refrigerant flow path is in the first state, the first control is performed so that the pressure in the first adsorbent increases. While the refrigerant flow path is in the second state, the first control is performed so that the pressure in the second adsorbent increases. The refrigeration apparatus according to claim 7.

13. The adsorbent includes a metal-organic structure containing metal ions and an organic ligand. A refrigeration apparatus according to any one of claims 1 to 3.

14. The refrigerant comprises at least one of carbon dioxide, hydrocarbons, ammonia, water, HFCs, and HFOs. A refrigeration apparatus according to any one of claims 1 to 3.

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