WO2020174684A1

WO2020174684A1 - Refrigeration cycle device

Info

Publication number: WO2020174684A1
Application number: PCT/JP2019/007924
Authority: WO
Inventors: 拓未西山; 伊東　大輔; 健太村田; 幹佐藤
Original assignee: 三菱電機株式会社
Priority date: 2019-02-28
Filing date: 2019-02-28
Publication date: 2020-09-03
Also published as: JP6972422B2; JPWO2020174684A1

Abstract

In a refrigeration cycle device (100) according to the present invention, a refrigerant containing R290 is circulated in a first circulation direction through a compressor (1), a first heat exchanger (3), a first pressure reduction device (31), and a second heat exchanger (4). The refrigeration cycle device (100) comprises a heat storage material (10) and a first flow path switching part (20). The heat storage material (10) is positioned around the compressor (1) and receives heat from the compressor (1). The first flow path switching part (20) can form a first flow path (FP1) and a second flow path (FP2) for leading the refrigerant from the second heat exchanger (4) to the compressor (1). When the first flow path (FP1) is formed, refrigerant flowing from the first flow path (FP1) reaches the compressor (1) without passing through the heat storage material (10). When the second flow path (FP2) is formed, refrigerant flowing from the second flow path (FP2) passes through the heat storage material (10) and then reaches the compressor (1).

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle device in which a heat storage material is formed around a compressor.

Conventionally, a refrigeration cycle device in which a heat storage material is formed around a compressor is known. For example, International Publication No. 2013/065233 (Patent Document 1) discloses a refrigeration cycle device in which a heat storage material is formed around a compressor. In the refrigeration cycle apparatus, in the defrosting operation, a flow path that guides the refrigerant from the outdoor heat exchanger to the suction port of the compressor via the heat storage material formed around the compressor is formed. According to the refrigeration cycle apparatus, it is possible to shorten the defrosting time, suppress a decrease in room temperature due to the defrosting operation, and improve comfort.

International Publication No. 2013/065233

In recent years, from the perspective of preventing global warming, refrigerants with lower GWP (Global Warming Potential) have been demanded. For refrigerants that can reduce GWP more than before, such as R290 (propane), the refrigerant with which the superheat degree of the refrigerant drawn into the compressor increases, the theoretical COP (Coefficient of Performance) of the refrigeration cycle device improves. There is. However, it is known that if the temperature of the refrigerant flowing out of the evaporator is increased in order to increase the degree of superheat of the refrigerant drawn into the compressor, the performance of the evaporator is deteriorated.

Patent Document 1 does not consider suppressing the temperature of the refrigerant flowing out of the evaporator during normal heating operation. When R290 is used for the refrigeration cycle device disclosed in Patent Document 1, the performance of the refrigeration cycle device may be reduced.

The present invention has been made to solve the above problems, and an object thereof is to suppress performance deterioration of a refrigeration cycle apparatus while reducing GWP.

In the refrigeration cycle device according to the present invention, the refrigerant containing R290 circulates in the first circulation direction of the compressor, the first heat exchanger, the first pressure reducing device, and the second heat exchanger. The refrigeration cycle device includes a heat storage material and a first flow path switching unit. The heat storage material is arranged around the compressor and receives heat from the compressor. The first flow path switching unit can form a first flow path and a second flow path for guiding the refrigerant from the second heat exchanger to the compressor. When the first flow path is formed, the refrigerant flowing out from the first flow path reaches the compressor without passing through the heat storage material. When the second flow path is formed, the refrigerant flowing out from the second flow path reaches the compressor via the heat storage material.

According to the refrigeration cycle apparatus of the present invention, the refrigerant containing R290 is used, and the flow path can be formed so that the refrigerant from the second heat exchanger reaches the compressor via the heat storage material. It is possible to suppress the performance deterioration of the refrigeration cycle device while reducing the GWP.

FIG. 3 is a functional block diagram showing the configuration of the refrigeration cycle device according to the first embodiment. It is the figure which planarly viewed the heat storage material of FIG. 1 from the normal direction of the side surface of the compressor 1. It is a figure which shows an example of the flow path formed in the inside of the heat storage material of FIG. It is a figure which shows many examples of the flow path formed inside the heat storage material of FIG. It is a figure which shows the relationship between the superheat degree of the refrigerant suck|inhaled by the compressor, and theoretical COP. FIG. 9 is a ph diagram showing the relationship between enthalpy, pressure, and temperature in a cooling operation under a low load of the refrigeration cycle apparatus according to the comparative example. 6 is a flowchart showing a flow of processing performed on the flow path switching unit by the control device of FIG. 1. It is a figure which shows the concrete structure of the flow-path switching part of FIG. It is a figure which shows the concrete structure of the other example of the flow-path switching part of FIG. It is a figure which shows an example of the heat storage material of FIG. It is a figure which shows the other example of the heat storage material of FIG. It is a functional block diagram which shows the structure of the refrigerating-cycle apparatus which concerns on Embodiment 2. 13 is a flowchart showing a flow of processing performed on the flow path switching unit by the control device of FIG. 12 in a cooling operation. FIG. 13 is a ph diagram showing the relationship between enthalpy, pressure, and temperature when the cooling operation is performed in the refrigeration cycle device according to the modification of the second embodiment. It is a functional block diagram which shows the structure of the refrigerating-cycle apparatus which concerns on Embodiment 3. 16 is a flowchart showing the flow of processing performed by the control device of FIG. 15 on the flow path switching unit during heating operation. It is a functional block diagram which shows the structure of the refrigerating-cycle apparatus which concerns on the modification 1 of Embodiment 3. It is a functional block diagram which shows the structure of the refrigerating-cycle apparatus which concerns on the modification 2 of Embodiment 3.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference symbols and description thereof will not be repeated in principle.

Embodiment 1.
FIG. 1 is a functional block diagram showing the configuration of the refrigeration cycle device 100 according to the first embodiment. As shown in FIG. 1, the refrigeration cycle apparatus 100 includes an outdoor unit 110 and an indoor unit 120. The outdoor unit 110 includes a compressor 1, a four-way valve 2 (second flow path switching unit), an outdoor heat exchanger 3 (first heat exchanger), an electromagnetic expansion valve 31 (first pressure reducing device), and a flow path. The path switching unit 20 (first flow path switching unit), the outdoor fan 41, the control device 90, and the temperature sensors 11 to 15 are included. The indoor unit 120 includes the indoor heat exchanger 4 (second heat exchanger), the indoor fan 42, and the temperature sensors 16-18. The control device 90 may be included in the indoor unit 120, or may be provided separately from the outdoor unit 110 and the indoor unit 120.

The refrigeration cycle apparatus 100 can perform cooling operation and heating operation on the space in which the indoor unit 120 is arranged. In the refrigeration cycle device 100, R290 is used as a refrigerant.

During cooling operation, the four-way valve 2 connects the discharge port Pd of the compressor 1 with the outdoor heat exchanger 3 and also connects the indoor heat exchanger 4 with the flow path switching unit 20. In the cooling operation, the refrigerant is discharged from the discharge port Pd of the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the electromagnetic expansion valve 31, the indoor heat exchanger 4, the four-way valve 2, the flow path switching unit 20, and the compressor 1. It circulates in the order of the suction port Ps.

During heating operation, the four-way valve 2 connects the discharge port Pd of the compressor 1 with the indoor heat exchanger 4, and also connects the outdoor heat exchanger 3 with the flow path switching unit 20. In the heating operation, the refrigerant is discharged from the discharge port Pd of the compressor 1, the four-way valve 2, the indoor heat exchanger 4, the electromagnetic expansion valve 31, the outdoor heat exchanger 3, the four-way valve 2, the flow path switching unit 20, and the compressor 1. It circulates in the order of the suction port Ps.

Referring to FIG. 2 together with FIG. 1, a heat storage material 10 that receives heat from the compressor 1 is arranged around the compressor 1. The heat storage material 10 covers the side surface of the compressor 1 except for the portion where the suction port Ps is formed. Between the compressor 1 and the heat storage material 10, in order to promote heat exchange between the heat storage material 10 and the refrigerant, a metal, grease, gel sheet or the like having high thermal conductivity may be provided. The heat exchange between the heat storage material 10 and the refrigerant may be promoted by tightening the outer peripheral portion of the heat storage material 10 with a belt or the like and bringing the heat storage material 10 into close contact with the compressor 1.

The flow path switching unit 20 can form a flow path FP1 (first flow path) and a flow path FP2 (second flow path). At least one of the flow paths FP1 and FP2 is open. The refrigerant flowing out of the flow path FP1 reaches the suction port Ps of the compressor 1 without passing through the heat storage material 10. The refrigerant flowing out of the flow path FP2 reaches the suction port Ps of the compressor 1 via the heat storage material 10. The flow paths in the heat storage material 10 may be formed so as to meander as shown in FIG. 3, or a plurality of flow paths may be formed in parallel as shown in FIG.

Referring again to FIG. 1, the control device 90 acquires from the temperature sensor 11 the temperature T11 of the refrigerant flowing between the outdoor heat exchanger 3 and the electromagnetic expansion valve 31. The control device 90 acquires the temperature T12 of the refrigerant flowing through the outdoor heat exchanger 3 from the temperature sensor 12 installed in the middle portion of the outdoor heat exchanger 3. The control device 90 acquires the temperature T13 of the outdoor space in which the outdoor unit 110 is arranged from the temperature sensor 13.

The control device 90 acquires the temperature T14 of the heat storage material 10 from the temperature sensor 14. When the heat storage material 10 is heated, convection occurs inside the heat storage material 10, and a high-temperature fluid having a low density gathers at the top of the heat storage material 10. As described later, the temperature T14 measured by the temperature sensor 14 is used to determine whether heating by the heat storage material 10 is possible. When the temperature sensor 14 is installed above the heat storage material 10, it can be determined that heating by the heat storage material 10 is possible, although the heat storage material 10 as a whole does not store sufficient heat. Therefore, the temperature measured by the temperature sensor 14 is preferably the temperature of the portion of the heat storage material 10 where the fluid having the lowest temperature can be collected. The temperature sensor 14 is preferably installed at a position that is ⅓ or less of the height of the heat storage material 10 from the top of the heat storage material 10. It is more preferable that the temperature sensor 14 is installed at a position that is ½ or less of the height of the heat storage material 10 from the top of the heat storage material 10.

The refrigerant passes through the flow path formed inside the heat storage material 10. Therefore, it is preferable that the temperature sensor 14 be able to directly measure the temperature inside the heat storage material 10. When it is difficult to directly measure the temperature inside the heat storage material 10, the other end of the object having a high thermal conductivity (for example, a rod-shaped metal) is exposed to the outside of the heat storage material 10. May be inserted into the heat storage material 10, and the temperature of the one end of the object may be measured by the temperature sensor 14.

The control device 90 acquires the temperature T15 of the refrigerant passing through the suction port Ps from the temperature sensor 15. The control device 90 acquires the temperature T16 of the refrigerant flowing between the indoor heat exchanger 4 and the electromagnetic expansion valve 31 from the temperature sensor 16. The control device 90 acquires the temperature T17 of the refrigerant passing through the indoor heat exchanger 4 from the temperature sensor 17 installed in the middle portion of the indoor heat exchanger 4. The control device 90 acquires the indoor temperature T18 of the indoor space in which the indoor unit 120 is arranged from the temperature sensor 18.

The control device 90 controls the drive frequency of the compressor 1 to control the amount of refrigerant that the compressor 1 discharges per unit time so that the indoor temperature T18 reaches a target temperature (for example, a temperature set by the user). To do. The control device 90 controls the four-way valve 2 to switch the circulation direction of the refrigerant. The controller 90 controls the flow passage switching unit 20 to adjust the amount of refrigerant passing through each of the flow passages FP1 and FP2 per unit time.

The control device 90 electromagnetically expands so that one or both of the degree of superheat of the refrigerant sucked into the compressor 1 and the degree of supercooling of the refrigerant flowing out of the heat exchanger functioning as a condenser have a value within a desired range. The opening degree of the valve 31 is controlled. The heat exchanger functioning as a condenser is the outdoor heat exchanger 3 in the cooling operation and the indoor heat exchanger 4 in the heating operation.

For example, when the superheat degree of the refrigerant sucked into the compressor 1 is set to a value in a desired range, the temperature T15 of the refrigerant sucked into the compressor 1 and the temperature (temperature T12 or T12) flowing through the heat exchanger functioning as an evaporator. The opening degree of the electromagnetic expansion valve 31 is controlled based on the temperature difference from T17). The heat exchanger functioning as an evaporator is the indoor heat exchanger 4 in the cooling operation and the outdoor heat exchanger 3 in the heating operation. When the degree of supercooling of the refrigerant flowing out from the heat exchanger functioning as the condenser is set to a value within a desired range, the temperature of the refrigerant flowing through the heat exchanger functioning as the condenser (temperature T12 or T17) and the heat exchanger concerned. The opening degree of the electromagnetic expansion valve 31 is controlled based on the temperature difference from the temperature (temperature T11 or T16) of the refrigerant flowing out from the.

The control device 90 controls the amount of air blown by the outdoor fan 41 and the indoor fan 42 per unit time. Regarding the outdoor fan 41, according to an operation mode (for example, a rated mode of high-speed rotation or an intermediate mode of low-speed rotation) that is automatically set from the temperature difference between the indoor target temperature and the indoor temperature T18, for each operation mode, The fan is driven at a preset rotational speed. As for the indoor fan 42, the fan is driven at a rotation speed according to a setting (for example, a weak wind mode or a strong wind mode) by the user. Regarding the indoor fan 42 as well, when the controller 90 allows automatic change of the rotation speed of the fan, for example, when the user selects the automatic mode, the fan is driven in the same manner as the outdoor fan. May be.

A temperature sensor that detects the temperature of the refrigerant passing through the discharge port Pd of the compressor 1 may be installed. Based on the temperature difference between the detection result of the temperature sensor and the preset target discharge temperature, the drive frequency of the compressor 1, the amount of air blown per unit time by the outdoor fan 41 and the indoor fan 42, and the electromagnetic expansion valve. The opening degree of 31 may be controlled.

In recent years, from the perspective of preventing global warming, refrigerants with lower GWP (Global Warming Potential) have been demanded. Examples of the refrigerant that can reduce the GWP more than the conventionally used refrigerant (for example, R410A) include R32 or R290.

Since R32 has a high operating pressure, the refrigeration effect of the refrigeration cycle device can be enhanced even with a relatively small compressor. In addition, R32 has no toxicity. However, the GWP of R32 is insufficient for the F-gas regulation or the regulation value of the Montreal Protocol. On the other hand, the GWP of R290 is lower than the GWP of R32. R290 is known as one of the effective refrigerants for these regulations.

Unlike R32 and R410A, R290 has the characteristic that the greater the degree of superheat of the refrigerant sucked into the compressor, the greater the theoretical COP (Coefficient of Performance) of the refrigeration cycle device (see Fig. 5). However, it is known that when the temperature of the refrigerant flowing out of the heat exchanger functioning as the evaporator is increased in order to increase the degree of superheat of the refrigerant sucked into the compressor, the performance of the heat exchanger is deteriorated. There is.

Further, when there is almost no temperature difference between the temperature of the refrigerant flowing out of the heat exchanger functioning as the condenser and the temperature of the refrigerant flowing out of the heat exchanger functioning as the evaporator, the degree of superheat of the refrigerant drawn into the compressor. Becomes difficult to secure. Such a situation may occur, for example, in a cooling operation at a low load.

FIG. 6 is a ph diagram showing the relationship between the enthalpy, the pressure, and the temperature in the cooling operation of the refrigeration cycle apparatus according to the comparative example at a low load. In FIG. 6, curves LC and GC represent a saturated liquid line and a saturated vapor line, respectively. The saturated liquid line and the saturated vapor line are connected at the critical point CP. The same applies to FIG. 14 described later. The process from the states C1 to C2 shows the adiabatic compression process by the compressor. The process from state C2 to C3 represents the condensation process with the heat exchanger functioning as a condenser. The process from the state C3 to C4 represents the depressurization process by the expansion valve. The process from state C4 to C1 represents the evaporation process by the heat exchanger functioning as an evaporator. FIG. 6 shows an isotherm of the outdoor temperature T1.

As shown in FIG. 6, when the temperature of the state C3 representing the state of the refrigerant flowing out of the heat exchanger functioning as the condenser is close to the outdoor temperature T1, the refrigerant is sucked into the compressor through the depressurization process and the evaporation process. The state C1 representing the state of the refrigerant may be on the isotherm of the outdoor temperature T1. In the low load cooling operation, the degree of superheat of the refrigerant drawn into the compressor may be lower than expected.

Therefore, in the refrigeration cycle apparatus 100, the heat generated in the compressor 1 is stored in the heat storage material 10, and the flow path FP2 is formed so that the refrigerant is sucked into the compressor 1 via the heat storage material 10. By using the heat accumulated in the heat storage material 10, it is possible to increase the degree of superheat of the refrigerant sucked into the compressor 1 while suppressing an increase in the temperature of the refrigerant flowing out from the heat exchanger functioning as an evaporator. it can. As a result, it is possible to improve the theoretical COP of the refrigeration cycle apparatus 100 in which the R290 is used to reduce the GWP while suppressing the performance degradation of the heat exchanger that functions as the evaporator.

FIG. 7 is a flowchart showing the flow of processing performed by the control device 90 of FIG. 1 for the flow path switching unit 20. The process shown in FIG. 7 is called at regular time intervals by a main routine (not shown) that performs integrated control of the refrigeration cycle apparatus 100. In the following, the step will be simply referred to as S.

The control device 90 determines in S101 whether the condition (specific condition) that the temperature T14 of the heat storage material 10 is equal to or higher than the reference temperature Tr1 is satisfied. When the temperature T14 of the heat storage material 10 is lower than the reference temperature Tr1 (for example, 30°) (NO in S101), the control device 90 causes the amount of the refrigerant per unit time passing through the flow path FP1 to pass through the flow path FP2 in S102. The flow path switching unit 20 is controlled so that the amount of refrigerant becomes greater than the amount of refrigerant per unit time, and the process is returned to the main routine. When the temperature T14 of the heat storage material 10 is equal to or higher than the reference temperature Tr1 (YES in S101), the control device 90 accumulates in the heat storage material 10 heat capable of heating the refrigerant flowing out from the heat exchanger functioning as the evaporator. In step S103, the flow passage switching unit 20 is controlled so that the amount of the refrigerant passing through the flow passage FP2 per unit time is larger than the amount of the refrigerant passing through the flow passage FP1 per unit time, and the process is performed in the main routine. return.

Note that the specific heat of the heat storage material 10 is preferably lower than the specific heat of water in order to shorten the time for the temperature T14 of the heat storage material 10 to reach the reference temperature Tr1. The reference temperature Tr1 is a temperature indicating that heat capable of heating the refrigerant flowing out from the heat exchanger functioning as an evaporator is accumulated in the heat storage material 10, and can be appropriately calculated by an actual machine experiment or simulation.

FIG. 8 is a diagram showing a specific configuration of the flow path switching unit 20 of FIG. As shown in FIG. 8, the flow path switching unit 20 includes electromagnetic opening/

closing valves

21 and 22. The electromagnetic opening/closing valve 21 is provided in the flow path FP1. When the electromagnetic opening/closing valve 21 is open, the refrigerant can pass through the flow path FP1. When the electromagnetic opening/closing valve 21 is closed, the refrigerant cannot pass through the flow path FP1. The electromagnetic opening/closing valve 22 is provided in the flow path FP2. When the electromagnetic opening/closing valve 22 is opened, the refrigerant can pass through the flow path FP2. When the electromagnetic opening/closing valve 22 is closed, the refrigerant cannot pass through the flow path FP2. The controller 90 opens the electromagnetic opening/closing valve 21 and closes the electromagnetic opening/closing valve 22 in S102 of FIG. 7. The control device 90 closes the electromagnetic opening/closing valve 21 and opens the electromagnetic opening/closing valve 22 in S103 of FIG. 7.

FIG. 9 is a diagram showing a specific configuration of a flow path switching unit 20A which is another example of the flow path switching unit 20 in FIG. As shown in FIG. 9, the flow path switching unit 20A includes

electromagnetic expansion valves

21A and 22A. The electromagnetic expansion valve 21A is provided in the flow path FP1. The controller 90 adjusts the amount of the refrigerant per unit time passing through the flow path FP1 by adjusting the opening degree of the electromagnetic expansion valve 21A. The electromagnetic expansion valve 22A is provided in the flow path FP2. The controller 90 adjusts the amount of the refrigerant per unit time passing through the flow path FP2 by adjusting the opening degree of the electromagnetic expansion valve 22A.

When the flow path switching unit 20 of FIG. 1 is the flow path switching unit 20A, the control device 90 adjusts the opening degree of each of the

electromagnetic expansion valves

21A and 22A, so that the refrigerant passing through the flow path FP1 per unit time. The flow rate ratio between the amount and the amount of refrigerant passing through the flow path FP2 per unit time is controlled.

According to the refrigeration cycle apparatus 100, the heat generated from the compressor 1 is used to heat the refrigerant via the heat storage material 10, so the energy efficiency of the refrigeration cycle apparatus is improved. Further, the heating of the refrigerant by the heat storage material 10 can increase the degree of superheat of the refrigerant drawn into the compressor 1 even in the heating operation and the low load cooling operation.

The amount of refrigerant dissolved in the lubricating oil of the compressor 1 decreases as the temperature of the refrigerant increases. Since the temperature of the refrigerant discharged from the compressor 1 also rises as the temperature of the refrigerant drawn into the compressor 1 rises, the amount of the refrigerant dissolved in the lubricating oil decreases. Since it is possible to suppress a decrease in the amount of the refrigerant circulating in the refrigeration cycle device due to the dissolution of the refrigerant in the lubricating oil, it is possible to reduce the amount of the refrigerant required for stable operation of the refrigeration cycle device.

When the outdoor temperature is relatively low (for example, in winter), the temperature of the heat storage material 10 may be lower than the temperature of the refrigerant flowing out from the heat exchanger functioning as the evaporator. When the refrigerant passes through the heat storage material 10 in such a case, the refrigerant is cooled by the heat storage material 10. Depending on the temperature of the heat storage material 10, the refrigerant may condense into a liquid refrigerant (liquid refrigerant). When the liquid refrigerant is sucked into the compressor 1, the performance of the compressor 1 deteriorates and the possibility of failure increases. In such a case (in step S101 of FIG. 7, NO), the refrigeration cycle apparatus 100 can return the refrigerant to the compressor 1 without passing through the heat storage material 10. As a result, the performance degradation of the compressor 1 can be suppressed.

The side surface of the compressor 1 covered by the heat storage material may be limited to the side surface portion around the motor in the compressor 1 that generates a large amount of heat, such as the heat storage material 10A shown in FIG. Further, the side surface of the compressor 1 covered by the heat storage material is limited to a portion around the flow path that guides the refrigerant from the flow path FP2 to the suction port Ps of the compressor 1 as in the heat storage material 10B shown in FIG. May be. By thus limiting the side surface on which the heat storage material is formed, the cost of the heat storage material can be reduced.

The refrigerant used in the refrigeration cycle device according to the first embodiment is such that the larger the degree of superheat of the refrigerant sucked into the compressor, the greater the theoretical COP (Coefficient of Performance) of the refrigeration cycle device is not lost. , R290 may be included.

In the first embodiment, the refrigeration cycle device including one outdoor unit and one indoor unit has been described. The refrigeration cycle apparatus may be configured to include a plurality of indoor units or may be configured to include a plurality of outdoor units.

In the first embodiment, the refrigeration cycle device such as the room air conditioner or the package air conditioner capable of switching between the cooling operation and the heating operation has been described. The refrigeration cycle apparatus may not have a flow path switching valve such as a four-way valve and may be configured only for cooling operation such as a refrigerator.

As described above, according to the refrigeration cycle device according to the first embodiment, it is possible to suppress the performance deterioration of the refrigeration cycle device while reducing the GWP.

Embodiment 2.
In Embodiment 2, a refrigeration cycle apparatus including an internal heat exchanger (third heat exchanger) will be described. In the internal heat exchanger, when the cooling operation is performed, the refrigerant (high-pressure side refrigerant) after being discharged from the compressor and before being decompressed by the expansion valve and the decompression by the expansion valve are performed. After that, heat is exchanged with the refrigerant (low-pressure side refrigerant) until it is taken into the compressor. In the second embodiment, when the cooling operation is performed, of the heating of the refrigerant by the internal heat exchanger and the heating of the refrigerant by the heat storage material, the degree of superheat of the refrigerant sucked into the compressor is further increased. Those who can do it are selected.

FIG. 12 is a functional block diagram showing the configuration of the refrigeration cycle device 200 according to the second embodiment. The configuration of the refrigeration cycle apparatus 200 is that the internal heat exchanger 51 and the temperature sensor 19 are added to the refrigeration cycle apparatus 100 of FIG. 1, and the control device 90 is replaced with 92. Other than these, it is the same, and therefore the description will not be repeated.

As shown in FIG. 12, the internal heat exchanger 51 is connected between the flow path FP1 and the suction port Ps of the compressor 1, and between the outdoor heat exchanger 3 and the electromagnetic expansion valve 31. It is connected. The control device 92 acquires the temperature T19 of the refrigerant flowing between the internal heat exchanger 51 and the electromagnetic expansion valve 31 from the temperature sensor 19. When the cooling operation is performed, in the internal heat exchanger 51, heat exchange is performed between the high pressure side refrigerant from the outdoor heat exchanger 3 functioning as a condenser and the low pressure side refrigerant from the flow path FP1. The low pressure side refrigerant is heated by the high pressure side refrigerant.

FIG. 13 is a flowchart showing a flow of processing performed on the flow path switching unit 20 by the control device 92 of FIG. 12 in the cooling operation. The process shown in FIG. 13 is called at regular time intervals by a main routine (not shown) that performs integrated control of the refrigeration cycle apparatus 200. The flowchart shown in FIG. 13 is a flowchart in which S101 of the flowchart shown in FIG. 7 is replaced with S201. The process shown in FIG. 7 is performed in the heating operation.

As shown in FIG. 13, the control device 92 satisfies the condition (specific condition) that the temperature T14 is equal to or higher than the reference temperature Tr1 and the difference between the temperatures T11 and T19 is equal to or lower than the reference value Tdr2 in S201. It is determined whether to do. The condition that the difference between the temperatures T11 and T19 is less than or equal to the reference value Tdr2 is a condition that indicates that the heat exchange amount in the internal heat exchanger 51 is smaller than the reference amount. The reference value Tdr2 is appropriately calculated by an actual machine experiment or simulation.

When temperature T14 is lower than reference temperature Tr1 or the difference between temperatures T11 and T19 is higher than reference value Tdr2 (NO in S201), control device 92 performs S102 similarly to the first embodiment to perform the process. Return to main routine. When temperature T14 is equal to or higher than reference temperature Tr1 and the difference between temperatures T11 and T19 is equal to or lower than reference value Tdr2 (YES in S201), control device 92 performs S103 similarly to the first embodiment to perform processing. Is returned to the main routine. In S201, the condition that the temperature T14 is equal to or higher than the reference temperature Tr1 or the difference between the temperatures T11 and T19 is equal to or lower than the reference value Tdr2 may be determined.

Modification of the second embodiment.
In the second embodiment, the case has been described where whether or not the heat exchange amount in the internal heat exchanger 51 is smaller than the reference amount is compared with the temperature difference and the reference value Tdr2. The temperature difference serving as an index of the amount of heat exchange in the internal heat exchanger 51 may change depending on the operating environment of the refrigeration cycle device 200 (for example, the outdoor temperature T13). In the second embodiment, the accuracy of determining whether or not the heat exchange amount in internal heat exchanger 51 is smaller than the reference amount is easily affected by the operating environment of refrigeration cycle apparatus 200.

Therefore, in the modification of the second embodiment, whether the amount of heat exchange in the internal heat exchanger 51 is smaller than the reference amount or not is a temperature ratio or an enthalpy ratio that is difficult to change due to changes in the operating environment of the refrigeration cycle apparatus 200. To determine. According to the refrigeration cycle apparatus according to the modified example of the second embodiment, the accuracy of determining whether the heat exchange amount in the internal heat exchanger 51 is smaller than the reference amount is maintained regardless of the operating environment of the refrigeration cycle apparatus. be able to.

In the configuration of the refrigeration cycle apparatus according to the modification of the second embodiment, the condition of T11-T19≦Tdr2 in S201 of FIG. 13 is changed to a condition related to temperature ratio or a condition related to enthalpy ratio. Other than that, since it is the same, the refrigeration cycle apparatus 200 of FIG. 13 will be described below as appropriate.

FIG. 14 is a ph diagram showing the relationship between the enthalpy, the pressure, and the temperature when the cooling operation is performed in the refrigeration cycle apparatus according to the modified example of the second embodiment. The process from the states C21 to C22 shows the adiabatic compression process by the compressor 1. The process from the state C22 to C25 represents the condensation process by the outdoor heat exchanger 3. The process from state C25 to C26 represents the depressurization process by the electromagnetic expansion valve 31. The process from state C26 to C21 represents the evaporation process by the indoor heat exchanger 4. In FIG. 14, an isotherm of the outdoor temperature T13 is shown.

As shown in FIG. 14, the temperature in the state C23 of the condensation process is the temperature T12 detected by the temperature sensor 12. Since the temperature of the single refrigerant R290 in the gas-liquid two-phase state is almost constant, the temperature of the state C24 of the condensation process on the saturated liquid line (the temperature of the saturated liquid) is the same temperature T12 as the state C23. The temperature in the state C25 is the temperature T19 detected by the temperature sensor 19.

In the following, the temperature ratio ΔT is the ratio of the temperature difference Δ2 between the temperature T12 and the temperature T19 to the temperature difference ΔT1 between the temperature T12 (first temperature) and the outdoor temperature T13. That is, ΔT=ΔT2/ΔT1. Further, the enthalpy ratio Δh is set to the enthalpy h12 (first enthalpy) of the saturated liquid state C24 and the enthalpy h24 of the state C25 (first enthalpy) and the enthalpy h19 (second enthalpy) of the liquid refrigerant at the outdoor temperature T13. 3) Enthalpy difference Δh2. That is, Δh=Δh2/Δh1.

When the operating environment of the refrigeration cycle device changes, both temperature differences ΔT1 and ΔT2 often change at the same rate. When both the denominator and the numerator of the temperature ratio ΔT change at the same rate, the temperature ratio ΔT hardly changes. The same applies to the enthalpy ratio.

In the refrigeration cycle apparatus according to the modification of the second embodiment, the condition of T11-T19≦Tdr2 in S201 of FIG. 13 is replaced with the condition of ΔT≧Rr1 or Δh≧Rr2 using the reference ratios Rr1 and Rr2. .. By comparing the temperature ratio or the enthalpy ratio with a predetermined reference ratio (for example, 0.8), the heat exchange amount in the internal heat exchanger 51 is smaller than the reference amount regardless of the operating environment of the refrigeration cycle device. It is possible to maintain the determination accuracy of whether or not. The reference ratios Rr1 and Rr2 are appropriately calculated by actual machine experiments or simulations. The reference ratios Rr1 and Rr2 may be the same.

As described above, according to the refrigeration cycle apparatus according to the second embodiment and the first modification, even when the heating by the heat storage material cannot be performed in the cooling operation, the superheat degree of the refrigerant sucked into the compressor by the internal heat exchanger is increased. Can be raised. As a result, it is possible to further reduce the performance deterioration of the refrigeration cycle apparatus as compared with the first embodiment while reducing the GWP.

Embodiment 3.
In the second embodiment, when the cooling operation is performed, of the heating of the refrigerant by the internal heat exchanger and the heating of the refrigerant by the heat storage material, the degree of superheat of the refrigerant sucked into the compressor is further increased. The case where the person who can do is selected is explained. In the third embodiment, even in the heating operation, one of the heating of the refrigerant by the internal heat exchanger and the heating of the refrigerant by the heat storage material that can further increase the degree of superheat of the refrigerant sucked into the compressor is selected. The case will be described.

FIG. 15 is a functional block diagram showing the configuration of the refrigeration cycle device 300 according to the third embodiment. The refrigeration cycle apparatus 300 has a configuration in which the electromagnetic expansion valve 32 (second pressure reducing apparatus) and the temperature sensor 19A are added to the refrigeration cycle apparatus 200 of FIG. 12, and the control device 92 is replaced with 93. Other than these, it is the same, and therefore the description will not be repeated.

As shown in FIG. 15, the electromagnetic expansion valve 32 is connected between the outdoor heat exchanger 3 and the internal heat exchanger 51. The control device 93 acquires the temperature T19A of the refrigerant flowing between the electromagnetic expansion valve 32 and the internal heat exchanger 51 from the temperature sensor 19A. The controller 93 fully opens the electromagnetic expansion valve 32 that does not reduce the pressure of the refrigerant during the cooling operation, and controls the opening degree of the electromagnetic expansion valve 31. The controller 93 fully opens the electromagnetic expansion valve 31 that does not reduce the pressure of the refrigerant during the heating operation, and controls the opening degree of the electromagnetic expansion valve 32.

FIG. 16 is a flowchart showing the flow of processing performed on the flow path switching unit 20 in the heating operation by the control device 93 of FIG. The flowchart shown in FIG. 16 is a flowchart in which S201 in FIG. 13 is replaced with S301. Note that the processing shown in FIG. 13 is performed in the cooling operation.

As shown in FIG. 16, the control device 93 satisfies the condition (specific condition) that the temperature T14 is equal to or higher than the reference temperature Tr1 and the difference between the temperatures T16 and T19A is equal to or lower than the reference value Tdr3 in S301. It is determined whether to do. The condition that the difference between the temperatures T16 and T19A is the reference value Tdr3 or less is a condition that indicates that the heat exchange amount in the internal heat exchanger 51 is smaller than the reference amount. The reference value Tdr3 can be appropriately calculated by an actual machine experiment or simulation.

If temperature T14 is lower than reference temperature Tr1 or the difference between temperatures T16 and T19A is higher than reference value Tdr3 (NO in S301), control device 93 performs S102 similarly to the first embodiment to perform the process. Return to main routine. When temperature T14 is equal to or higher than reference temperature Tr1 and the difference between temperatures T16 and T19A is equal to or lower than reference value Tdr3 (YES in S301), control device 93 performs S103 similarly to the first embodiment. Is returned to the main routine.

Note that in S301, the condition that the temperature T14 is equal to or higher than the reference temperature Tr1 or the difference between the temperatures T16 and T19A is equal to or lower than the reference value Tdr3 may be determined. Further, in S301, similarly to the modification of the second embodiment, the condition regarding the temperature ratio or the condition regarding the enthalpy ratio may be used. In that case, temperatures T12, T13, and T19 in the modification of the second embodiment are replaced with temperatures T17, T18, and T19A, respectively.

Modification 1 of the third embodiment.
In the first modification of the third embodiment, a configuration in which a pressure loss is reduced by connecting a check valve in parallel to each of the two electromagnetic expansion valves will be described.

FIG. 17 is a functional block diagram showing the configuration of the refrigeration cycle apparatus 300A according to the first modification of the third embodiment. The refrigeration cycle apparatus 300A has a configuration in which the

check valves

61 and 62 are added to the refrigeration cycle apparatus 300 of FIG. 15 and the control device 93 is replaced with 93A. Other than these, it is the same, and therefore the description will not be repeated.

As shown in FIG. 17, the check valve 61 is connected in parallel to the electromagnetic expansion valve 31 between the indoor heat exchanger 4 and the internal heat exchanger 51. The forward direction of the check valve 61 is the direction from the indoor heat exchanger 4 to the internal heat exchanger 51. The pressure loss when the refrigerant flows in the forward direction of the check valve 61 is smaller than the pressure loss when the refrigerant flows through the fully-opened electromagnetic expansion valve 31.

The check valve 62 is connected in parallel to the electromagnetic expansion valve 32 between the outdoor heat exchanger 3 and the internal heat exchanger 51. The forward direction of the check valve 62 is the direction from the outdoor heat exchanger 3 to the internal heat exchanger 51. The pressure loss when the refrigerant flows in the forward direction of the check valve 62 is smaller than the pressure loss when the refrigerant flows in the fully-opened electromagnetic expansion valve 32.

During the cooling operation, the control device 93A closes the electromagnetic expansion valve 32. In the cooling operation, the refrigerant from the outdoor heat exchanger 3 passes through the check valve 62, the internal heat exchanger 51, and the electromagnetic expansion valve 31 in this order. In the heating operation, the control device 93A closes the electromagnetic expansion valve 31. In the heating operation, the refrigerant from the indoor heat exchanger 4 passes through the check valve 61, the internal heat exchanger 51, and the electromagnetic expansion valve 32 in this order.

In the refrigeration cycle apparatus 300A, the electromagnetic expansion valve that does not reduce the pressure of the refrigerant is closed, and the flow path is formed so that the refrigerant passes through the check valve with the smaller pressure loss. Performance deterioration due to pressure loss of the electromagnetic expansion valve can be suppressed. The user can appropriately select the

refrigeration cycle devices

300 and 300A in consideration of the cost increase and the performance improvement due to the addition of the two check valves.

Modification 2 of the third embodiment.
In the third embodiment and the first modification, in the internal heat exchanger 51, heat exchange is performed between the high pressure side refrigerant from the heat exchanger functioning as a condenser and the low pressure side refrigerant from the flow path FP1. The case was explained. In the second modification of the third embodiment, the case where the high-pressure side refrigerant is the refrigerant discharged from the compressor 1 will be described.

FIG. 18 is a functional block diagram showing a configuration of a refrigeration cycle apparatus 300B according to Modification 2 of Embodiment 3. The configuration of the refrigeration cycle apparatus 300B is such that an internal heat exchanger 51B and a temperature sensor 19B are added in place of the internal heat exchanger 51 and the temperature sensor 19 of FIG. 12, the control device 92 is replaced by 93B, and the temperature sensor 11B and the electromagnetic sensor. This is a configuration in which an expansion valve 32B is added. Other than these, it is the same, and therefore the description will not be repeated.

As shown in FIG. 18, the internal heat exchanger 51B is connected between the flow path FP1 and the suction port Ps of the compressor 1. The internal heat exchanger 51B and the electromagnetic expansion valve 32B are connected in series in this order between the discharge port Pd of the compressor 1 and the flow path between the outdoor heat exchanger 3 and the electromagnetic expansion valve 31. In the internal heat exchanger 51B, heat is exchanged between the high pressure side refrigerant discharged from the compressor 1 and the low pressure side refrigerant from the flow path FP1, and the low pressure side refrigerant is heated by the high pressure side refrigerant.

The control device 93B controls the opening degree of the electromagnetic expansion valve 32B. The controller 93B acquires the temperature T19B of the refrigerant flowing between the internal heat exchanger 51B and the electromagnetic expansion valve 32B from the temperature sensor 19B. The control device 93B acquires the temperature T11B of the refrigerant passing through the discharge port Pd of the compressor 1 from the temperature sensor 11B.

The process flow for the flow path switching unit 20 performed in the cooling operation and the heating operation by the control device 93B is configured such that the temperatures T11, T19 and the reference value Tdr2 in FIG. 13 are replaced with the temperatures T11B, T19B and the reference value Tdr4, respectively. Is. The reference value Tdr4 is appropriately determined by an actual machine experiment or simulation. The reference value Tdr4 may be the same as the reference value Tdr2.

As described above, according to the refrigeration cycle apparatus according to the third embodiment and the modified examples 1 and 2, even when heating by the heat storage material cannot be performed in both the cooling operation and the heating operation, the internal heat exchanger causes the compressor to operate. The degree of superheat of the drawn refrigerant can be increased. As a result, it is possible to further suppress the performance deterioration of the refrigeration cycle apparatus as compared with the second embodiment while reducing the GWP.

-Each embodiment disclosed this time is also planned to be appropriately combined and implemented within a range where there is no contradiction. It should be considered that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

1 compressor, 2 four-way valve, 3 outdoor heat exchanger, 4 indoor heat exchanger, 10, 10A, 10B heat storage material, 11-19, 11B, 19A, 19B temperature sensor, 20, 20A flow

path switching part

21, 22 electromagnetic on-off valve, 21A, 22A, 31, 32, 32B electromagnetic expansion valve, 41 outdoor fan, 42 indoor fan, 51, 51B internal heat exchanger, 61, 62 check valve, 90, 92, 93, 93A, 93B Control device, 100, 200, 300, 300A, 300B refrigeration cycle device, 110 outdoor unit, 120 indoor unit, FP1, FP2 flow path, Pd discharge port, Ps suction port.

Claims

A refrigeration cycle apparatus in which a refrigerant containing R290 circulates in a first circulation direction of a compressor, a first heat exchanger, a first pressure reducing device, and a second heat exchanger,
A heat storage material that is arranged around the compressor and receives heat from the compressor,
A first flow path switching unit capable of forming a first flow path and a second flow path for guiding the refrigerant from the second heat exchanger to the compressor,
When the first flow path is formed, the refrigerant flowing out of the first flow path reaches the compressor without passing through the heat storage material,
A refrigeration cycle apparatus in which, when the second flow path is formed, the refrigerant flowing out of the second flow path reaches the compressor via the heat storage material.
Further comprising a control device for controlling the first flow path switching unit,
The control device is
When the specific condition is satisfied, the first flow path switching unit is controlled to close the first flow path and open the second flow path,
When the specific condition is not satisfied, the first flow path switching unit is controlled to open the first flow path and close the second flow path,
The refrigeration cycle apparatus according to claim 1, wherein the specific condition includes a condition that the temperature of the heat storage material is higher than a reference temperature.
A third heat exchanger in which heat is exchanged between the refrigerant from the first heat exchanger and the refrigerant from the first flow path;
Further comprising a control device for controlling the first flow path switching unit,
The control device is
When the specific condition is satisfied, the first flow is adjusted so that the amount of the refrigerant per unit time passing through the second flow path is larger than the amount of the refrigerant per unit time passing through the first flow path. Controls the path switching unit,
If the specific condition is not satisfied, the amount of the refrigerant per unit time passing through the first flow path may be greater than the amount of the refrigerant per unit time passing through the second flow path. Controls the flow path switching unit,
The refrigeration cycle apparatus according to claim 1, wherein the specific condition includes a condition indicating that a heat exchange amount in the third heat exchanger is smaller than a reference amount.
The condition indicating that the amount of heat exchange in the third heat exchanger is smaller than the reference amount is that the temperature of the refrigerant flowing between the first heat exchanger and the third heat exchanger and the third heat exchanger. The refrigeration cycle apparatus according to claim 3, further comprising a condition that a difference between the refrigerant and the temperature of the refrigerant flowing between the first pressure reducing devices is smaller than a reference value.
The first heat exchanger is arranged outdoors,
The condition indicating that the amount of heat exchange in the third heat exchanger is smaller than the reference amount is that the first temperature with respect to the difference between the first temperature and the outdoor temperature of the saturated liquid of the refrigerant passing through the first heat exchanger. The refrigeration cycle apparatus according to claim 3, further comprising a condition that a ratio of a difference in temperature of the refrigerant flowing out from the third heat exchanger is larger than a reference ratio.
The first heat exchanger is arranged outdoors,
The condition indicating that the amount of heat exchange in the third heat exchanger is smaller than the reference amount is that the first enthalpy of the saturated liquid of the refrigerant passing through the first heat exchanger and the first of the liquid refrigerant at the outdoor temperature. The refrigeration cycle apparatus according to claim 3, further comprising a condition that a ratio of a difference between the first enthalpy and the third enthalpy of the refrigerant flowing out of the third heat exchanger with respect to a difference between two enthalpies is larger than a reference ratio.
The refrigeration cycle apparatus according to any one of claims 3 to 6, wherein the specific condition further includes a condition that the temperature of the heat storage material is higher than a reference temperature.
A second flow path switching unit that switches the circulation direction of the refrigerant between the first circulation direction and a second circulation direction opposite to the first circulation direction;
Further comprising a second pressure reducing device connected between the first heat exchanger and the third heat exchanger,
When the circulation direction of the refrigerant is the first circulation direction, the control device fully opens the opening degree of the second pressure reducing device,
The refrigeration cycle apparatus according to claim 3, wherein when the circulation direction of the refrigerant is the second circulation direction, the control device fully opens the first decompression device.
A second flow path switching unit that switches the circulation direction of the refrigerant between the first circulation direction and a second circulation direction opposite to the first circulation direction;
A second pressure reducing device connected between the first heat exchanger and the third heat exchanger;
A first check valve connected in parallel to the first pressure reducing device between the second heat exchanger and the third heat exchanger;
Further comprising a second check valve connected in parallel to the second pressure reducing device between the first heat exchanger and the third heat exchanger,
The forward direction of the first check valve is a direction from the second heat exchanger to the third heat exchanger,
The forward direction of the second check valve is a direction from the first heat exchanger to the third heat exchanger,
When the circulation direction of the refrigerant is the first circulation direction, the control device closes the second pressure reducing device,
The refrigeration cycle apparatus according to claim 3, wherein the control device closes the first pressure reducing device when the circulation direction of the refrigerant is the second circulation direction.
A third heat exchanger in which heat is exchanged between the refrigerant from the compressor and the refrigerant from the first flow path,
A second pressure reducing device connected between the third heat exchanger and the flow path between the first pressure reducing device and the first heat exchanger;
Further comprising a control device for controlling the first flow path switching unit,
The control device is
When the specific condition is satisfied, the amount of the refrigerant passing through the first flow path per unit time is reduced and the second flow path is opened,
If the specific condition is not satisfied, the amount of the refrigerant per unit time passing through the first flow path is increased and the second flow path is closed,
The refrigeration cycle apparatus according to claim 1, wherein the specific condition includes a condition indicating that a heat exchange amount in the third heat exchanger is smaller than a reference amount.