WO2024009504A1

WO2024009504A1 - Refrigeration cycle device

Info

Publication number: WO2024009504A1
Application number: PCT/JP2022/027117
Authority: WO
Inventors: 孔明仲島
Original assignee: 三菱電機株式会社
Priority date: 2022-07-08
Filing date: 2022-07-08
Publication date: 2024-01-11

Abstract

This refrigeration cycle device (100) comprises: a first circulation flow path (L1) by which a compressor (10), a first heat exchanger (20), a depressurization device (30), and a second heat exchanger (40) are connected and in which a first refrigerant is circulated; an accumulator (21); and a heat pipe circuit (50). The heat pipe circuit (50) is provided with a heat-absorbing part (51E), a heat-releasing part (51D), and a fixed-pressure valve (55). A second circulation flow path (L2) is provided with a gas phase flow path (50G) and a liquid phase flow path (50L). The fixed-pressure valve (55) attains a closed state when the pressure of a second refrigerant is equal to or greater than a stipulated value, and attains an open state when the pressure of the second refrigerant is less than the stipulated value.

Description

Refrigeration cycle equipment

The present disclosure relates to a refrigeration cycle device.

Conventionally, there are refrigeration cycle devices that include an accumulator to suppress liquid refrigerant from being sucked into the compressor. Accumulators used in refrigeration cycles separate refrigerant into two phases: gas and liquid. Specifically, liquid refrigerant is stored at the bottom of the accumulator, and gas refrigerant is discharged from the top of the accumulator. In such an accumulator, the amount of liquid refrigerant stored in the accumulator increases when the refrigeration cycle is not operated for a long period of time, or when the compressor is operated intermittently with repeated on and off states. . If the amount of stored liquid refrigerant increases excessively, the possibility that the liquid refrigerant will be sucked into the compressor increases, and the amount of circulating refrigerant also decreases.

JP-A-7-301459 (Patent Document 1) discloses that in order to prevent liquid refrigerant from being excessively stored in the accumulator, the liquid refrigerant in the accumulator is heated to evaporate and discharged as a gas refrigerant. A heat pump device is disclosed. In JP-A-7-301459 (Patent Document 1), an electric heater is used as a heating means.

On the other hand, Japanese Unexamined Patent Publication No. 2013-185761 (Patent Document 2) discloses a method in which heat generated in a compressor is transferred to liquid refrigerant in an accumulator without using energy from outside the refrigeration cycle device. A refrigerant heating system having a heat pipe for heating a liquid refrigerant is disclosed. Heat from the compressor side that contacts one end of the heat pipe is transferred to the accumulator side that contacts the other end of the heat pipe. In this manner, the refrigerant heating system disclosed in Japanese Patent Application Publication No. 2013-185761 (Patent Document 2) evaporates the refrigerant in the liquid state in the accumulator without requiring energy from outside the refrigeration cycle device.

Japanese Patent Application Publication No. 7-301459 Japanese Patent Application Publication No. 2013-185761

As described in Japanese Unexamined Patent Publication No. 2013-185761 (Patent Document 2), if a heat pipe is used to heat the liquid refrigerant in the accumulator, the accumulator can be heated without requiring external energy. As long as there is a temperature difference between one end of the pipe in contact with the compressor and the other end in contact with the accumulator, heat exchange will always take place. Therefore, even if there is no liquid refrigerant in the accumulator, the heat pipe transfers the heat generated in the compressor to the accumulator.

As a result, the thermal energy generated in the compressor that should be used for the refrigeration cycle process itself is used to heat the accumulator in which no liquid refrigerant remains. That is, the heat generated in the compressor is transferred unnecessarily.

The present disclosure has been made to solve such problems, and the purpose is to provide a refrigeration cycle that heats an accumulator using thermal energy on the compressor side without requiring energy from outside the refrigeration cycle device. To provide a refrigeration cycle device that suppresses thermal energy generated on a compressor side from being transmitted to an accumulator side when no liquid refrigerant to be evaporated remains in the accumulator. .

A refrigeration cycle device in the present disclosure connects a compressor, a first heat exchanger, a pressure reduction device, a second heat exchanger, a compressor, a first heat exchanger, a pressure reduction device, and a second heat exchanger. The refrigerant refrigerant includes a first circulation channel for circulating the first refrigerant, an accumulator provided on the refrigerant suction side of the compressor, and a heat pipe circuit connecting the compressor and the accumulator. The heat pipe circuit includes a loop-type second circulation flow path that circulates the second refrigerant, a heat absorption part that absorbs heat from the first refrigerant in the compressor, a heat radiation part that radiates heat to the first refrigerant in the accumulator, and a second refrigerant. and a constant pressure valve that can shut off the circulation. The second circulation flow path includes a gas phase flow path through which the second refrigerant in a gaseous state passes, and a liquid phase flow path through which the second refrigerant in a liquid state passes. The constant pressure valve is provided in the liquid phase flow path, and is closed when the pressure of the second refrigerant is equal to or higher than a prescribed value, and is opened when the pressure of the second refrigerant is less than a prescribed value.

According to the present disclosure, in a refrigeration cycle device that heats an accumulator using thermal energy from a compressor without requiring energy from outside the refrigeration cycle device, liquid refrigerant to be evaporated remains in the accumulator. If not, it is possible to suppress the thermal energy generated on the compressor side from being transmitted to the accumulator side.

1 is a diagram showing the configuration of a refrigeration cycle device in Embodiment 1. FIG. FIG. 3 is a diagram for explaining the arrangement relationship of an accumulator, a compressor, and a heat pipe circuit. FIG. 3 is a diagram for explaining the internal structure of a heat pipe circuit. FIG. 3 is a diagram for explaining the pressure increase of the second refrigerant using a Ph diagram (Mollier diagram). FIG. 3 is a diagram for explaining the internal structure of the heat pipe circuit when no liquid refrigerant to be evaporated remains in the accumulator. FIG. 3 is a diagram for explaining the internal structure of a heat pipe circuit in Embodiment 2. FIG. FIG. 7 is a diagram for explaining the internal structure of the heat pipe circuit when no liquid refrigerant to be evaporated remains in the accumulator in Embodiment 2. FIG. 7 is a diagram for explaining a modification of the internal structure of the heat pipe circuit in Embodiment 2. FIG.

Hereinafter, embodiments of the technical idea according to the present disclosure will be described with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

Embodiment 1.
<Configuration of refrigeration cycle system and circulation of first refrigerant>
FIG. 1 is a diagram showing the configuration of a refrigeration cycle device 100 in the first embodiment. Refrigeration cycle device 100 in this embodiment is used as an air conditioner. Below, the outline of each structure with which refrigeration cycle device 100 is provided is explained. The refrigeration cycle device 100 includes a circulation channel L1 in which a first refrigerant is sealed. The refrigeration cycle device 100 performs refrigeration cycle processing by circulating the first refrigerant within the circulation flow path L1. The refrigeration cycle device 100 includes a compressor 10, a four-way valve 45, a first heat exchanger 20, an expansion valve 30, a second heat exchanger 40, and an accumulator 21.

The four-way valve 45 switches the flow path through which the first refrigerant flows in the circulation flow path L1. In this embodiment, the state of the four-way valve 45 is switched between a first state and a second state, and FIG. 1 shows the circulation flow path L1 when the four-way valve 45 is in the first state. When the four-way valve 45 is in the first state, the first refrigerant circulates through the compressor 10, the four-way valve 45, the first heat exchanger 20, the expansion valve 30, the second heat exchanger 40, and the accumulator 21 in this order. The type of the first refrigerant is, for example, an HFC refrigerant or a natural refrigerant. The natural refrigerant is, for example, a refrigerant made of carbon dioxide, hydrocarbon, helium, or the like.

When the four-way valve 45 is switched from the first state to the second state, the first refrigerant flows through the compressor 10, the four-way valve 45, the second heat exchanger 40, the expansion valve 30, the first heat exchanger 20, and the accumulator. It circulates in the order of 21. That is, depending on the state of the four-way valve 45, the inflow direction of the first refrigerant in the pipes connecting each of the four-way valve 45, the first heat exchanger 20, the expansion valve 30, and the second heat exchanger 40 is reversed. Below, the configuration of the refrigeration cycle device 100 will be described in the order in which the first refrigerant flows through the circulation channel L1 in the first state shown in FIG.

The compressor 10 is configured to compress the first refrigerant in a gaseous state within the circulation flow path L1. The refrigerant discharged from the compressor 10 becomes a high-temperature, high-pressure superheated gas state. Direction D is the direction in which the compressor 10 discharges refrigerant. In the following, in the circulation flow path L1, the direction in which the refrigerant flows from an arbitrary position is sometimes referred to as "downstream", and the direction opposite to "downstream" and in which the refrigerant flows is sometimes referred to as "upstream". . For example, accumulator 21 is placed upstream of compressor 10, and compressor 10 is placed downstream of accumulator 21. Although the number of compressors included in the refrigeration cycle device 100 is one in this embodiment, the refrigeration cycle device 100 may be equipped with a plurality of compressors.

When the four-way valve 45 is in the first state, the first heat exchanger 20 functions as a condenser. Due to the forced convection generated by the blower F1, the gas refrigerant passing through the first heat exchanger 20 exchanges heat with the air surrounding the first heat exchanger 20. Thereby, the refrigerant passing through the first heat exchanger 20 is condensed and becomes liquid refrigerant. The liquid refrigerant is depressurized by the expansion valve 30 and becomes a gas-liquid two-phase refrigerant. The expansion valve 30 may correspond to a "pressure reducing device" in the present disclosure.

The refrigerant in a gas-liquid two-phase state passes through the extension pipe P1 and flows into the second heat exchanger 40. When the four-way valve 45 is in the first state, the second heat exchanger 40 functions as an evaporator. In the second heat exchanger 40, the gas-liquid two-phase refrigerant exchanges heat with the air around the second heat exchanger 40 by forced convection generated by the blower F2. As a result, a part of the gas-liquid two-phase refrigerant passing through the second heat exchanger 40 evaporates, and the proportion of the gas-state first refrigerant in the gas-liquid two-phase first refrigerant increases.

However, the first refrigerant after passing through the second heat exchanger 40 also contains liquid refrigerant, and in order to prevent this liquid refrigerant from being sucked into the compressor 10, the accumulator 21 Separate the refrigerant and gas refrigerant. The gas-liquid two-phase first refrigerant that has passed through the second heat exchanger 40 passes through the extension pipe P2, passes through the four-way valve 45, and flows into the accumulator 21. The accumulator 21 stores surplus liquid refrigerant among the gas-liquid two-phase refrigerant flowing from the second heat exchanger 40 .

The gas refrigerant separated by the accumulator 21 returns to the compressor 10 and is compressed by the compressor 10 again. In this way, in the refrigeration cycle device 100, each component included in the refrigeration cycle device 100 forms a refrigeration cycle in which the first refrigerant circulates through the circulation channel L1. Note that when the four-way valve 45 is in the second state, the first heat exchanger 20 functions as an evaporator, and the second heat exchanger 40 functions as a condenser.

The accumulator 21 separates a liquid refrigerant and a gas refrigerant, and stores the separated liquid refrigerant at the bottom of the accumulator 21. If the amount of liquid refrigerant stored in the accumulator 21 increases, the possibility that the liquid refrigerant will be sucked into the compressor 10 will increase, and the amount of refrigerant circulating through the circulation path L1 will decrease. Therefore, the refrigeration cycle device 100 of the present embodiment is provided with a loop-type heat pipe circuit 50 for evaporating the liquid refrigerant stored in the accumulator 21. In this embodiment, the heat absorption part of the heat pipe circuit 50 contacts the compressor 10, and the heat radiation part of the heat pipe circuit 50 contacts the accumulator 21. Thereby, the heat pipe circuit 50 transfers the heat generated by the compressor 10 to the liquid refrigerant remaining in the accumulator 21, and evaporates the liquid refrigerant in the accumulator 21.

As described above, the refrigeration cycle device 100 in this embodiment is used as an air conditioner, and can perform heating operation by switching the four-way valve 45. In the refrigeration cycle device 100 according to the present embodiment, when heating operation is performed, the thermal energy within the compressor 10 is not transferred unnecessarily, thereby making it possible to improve indoor heating efficiency.

<Arrangement relationship among accumulator 21, compressor 10, and heat pipe circuit 50>
FIG. 2 is a diagram for explaining the arrangement relationship among the accumulator 21, compressor 10, and heat pipe circuit 50. In the following description, the vertical direction will be referred to as the "Z-axis direction," the direction perpendicular to the Z-axis direction will be referred to as the "X-axis direction," and the direction perpendicular to both the Z-axis and the X-axis will be referred to as the "Y-axis direction.""axialdirection". Furthermore, hereinafter, the positive direction of the Z-axis in each figure may be referred to as the upper side, and the negative direction may be referred to as the lower side.

As shown in FIG. 2, the gas-liquid two-phase first refrigerant flows into the accumulator 21 through the pipe P3. The accumulator 21 has a container that stores liquid refrigerant, and the container is, for example, cylindrical with a circular cross section. FIG. 2 shows a space 21S inside the container of the accumulator 21 and a liquid level Sf1 of the liquid refrigerant stored in the accumulator 21. In the accumulator 21, liquid refrigerant is stored on the negative side of the Z-axis due to gravity, while gas refrigerant is present on the positive side of the Z-axis. Thereby, only the gas refrigerant is discharged to the compressor 10 through the pipe P4 extending from the negative direction side to the positive direction side of the Z axis shown in FIG.

A part of the heat pipe circuit 50 is arranged in the space 21S within the accumulator 21. In the example shown in FIG. 2, the liquid level Sf1 is on the positive side of the Z-axis of the heat pipe circuit 50 in the space 21S. That is, all of the heat pipe circuits 50 in the space 21S are submerged in the liquid refrigerant in the accumulator 21.

The gas refrigerant passing through the pipe P4 flows into the compressor 10. Compressor 10 includes a shell 11, a shaft 14, a compression mechanism 15, and a motor 17. The compression mechanism 15, the shaft 14, and the motor 17 are arranged in a space 10S inside the shell 11.

A pipe P4 for causing the gas refrigerant to flow into the compression mechanism 15 of the compressor 10 and a pipe P5 for flowing the gas refrigerant to the outside of the compressor 10 are connected to the shell 11. The gas refrigerant that has flowed into the compression mechanism 15 is compressed to a high temperature and high pressure, and is discharged from the pipe P5. That is, the compression mechanism 15 is configured to compress the gas refrigerant that has flowed into the shell 11 from the pipe P4 and discharge it from the pipe P5.

The compression mechanism 15 is, for example, a rotary type compression mechanism. Motor 17 drives compression mechanism 15 through shaft 14 . Motor 17 includes rotor 12 and stator 13. The rotor 12 is connected to a shaft 14 by a connection portion (not shown). The compressed gas refrigerant is discharged from the discharge hole 16 of the compression mechanism 15 into the space 10S. The discharged high-temperature, high-pressure gas refrigerant passes through the gap in the motor 17 (the gap between the rotor 12 and the stator 13, the groove provided on the outer peripheral surface of the stator 13, etc.), and then is discharged from the pipe P5 to the four-way valve 45.

As shown in FIG. 2, a portion of the heat pipe circuit 50 is arranged in the space 10S within the shell 11. That is, all of the heat pipe circuits 50 in the space 10S are exposed to the high temperature and high pressure gas refrigerant.

<Internal structure of heat pipe circuit>
FIG. 3 is a diagram for explaining the internal structure of the heat pipe circuit 50. FIG. 3 shows a cross section of a loop-type heat pipe circuit 50. The heat pipe circuit 50 has a loop-type circulation flow path L2 that circulates the second refrigerant. As shown in FIG. 3, in the first embodiment, the loop-type heat pipe circuit 50 has a rectangular cross section. A second refrigerant is sealed in the circulation flow path L2. The type of second refrigerant is, for example, an HFC refrigerant or a natural refrigerant. The type of first refrigerant and the type of second refrigerant may be the same. In this case, the refrigeration cycle device 100 can be constructed from one type of refrigerant, and therefore, cost increases can be suppressed.

The heat pipe circuit 50 includes a heat radiation section 51D, a heat absorption section 51E, a constant pressure valve 55, a gas phase flow path 50G, and a liquid phase flow path 50L. In FIG. 2, a liquid level Sf2 is shown in the heat radiating part 51D, and a liquid level Sf3 is shown in the heat absorbing part 51E. That is, in the example of FIG. 2, the liquid phase of the enclosed second refrigerant exists on the negative side of the Z-axis of the heat pipe circuit 50. Further, the gas phase of the enclosed second refrigerant exists on the positive side of the Z-axis of the heat pipe circuit 50.

The heat absorbing section 51E absorbs heat from the first refrigerant in a high temperature and high pressure gas state passing through the space 10S in the compressor 10. The heat absorbing portion 51E is a region of the heat pipe circuit 50 that can come into contact with the first refrigerant in a gaseous state at high temperature and high pressure. In the heat absorption section 51E, the second refrigerant in the heat pipe circuit 50 exchanges heat with the first refrigerant in the compressor 10. Thereby, the second refrigerant changes from a liquid state to a gas state in the heat absorption part 51E. In other words, the second refrigerant evaporates.

On the other hand, the heat radiation section 51D radiates heat to the first refrigerant in a liquid state remaining in the space 21S of the accumulator 21. The heat radiation section 51D is a region of the heat pipe circuit 50 that can come into contact with the first refrigerant in the accumulator 21. That is, in the heat radiation section 51D, the second refrigerant in the heat pipe circuit 50 exchanges heat with the first refrigerant in the accumulator 21. As a result, the second refrigerant changes from a gas state to a liquid state in the heat radiation section 51D. In other words, the second refrigerant condenses. On the other hand, as shown in FIG. 2, the first refrigerant evaporates and undergoes nucleate boiling.

As shown in FIG. 3, the heat radiation part 51D has a length D2 with respect to the X-axis direction parallel to the liquid surface Sf1. Moreover, the heat radiation part 51D has a length D1 with respect to the Z-axis direction, which is the normal direction to the liquid surface Sf1. In the example of FIG. 3, length D1 is shorter than length D2.

Due to the evaporation of the second refrigerant in the heat absorption part 51E and the condensation of the second refrigerant in the heat radiation part 51D, a difference Df1 occurs in the height of the liquid surface Sf2 and the liquid surface Sf3 in the Z-axis direction. The density of the second refrigerant in the liquid state is greater than the density of the second refrigerant in the gas state. Therefore, due to the difference Df1 occurring, the second refrigerant in the heat radiation part 51D passes through the liquid phase flow path 50L arranged on the negative side of the Z axis in the circulation flow path L2, and flows to the heat absorption part 51E. Inflow.

Further, the second refrigerant in the heat absorption part 51E passes through the gas phase flow path 50G arranged on the positive side of the Z-axis in the circulation flow path L2, and returns to the heat radiation part 51D. In this way, in the loop-type heat pipe circuit 50, the second refrigerant circulates by evaporating the second refrigerant in the heat absorption section 51E and condensing the second refrigerant in the heat radiation section 51D. In the example cross-sectional view of FIG. 2, the second refrigerant is circulating counterclockwise.

The constant pressure valve 55 is provided on the liquid phase flow path 50L. The constant pressure valve 55 is configured to be able to cut off circulation of the second refrigerant. More specifically, the constant pressure valve 55 is configured to be in a closed state when the pressure of the second refrigerant is equal to or higher than a specified value. That is, the constant pressure valve 55 blocks the circulation of the second refrigerant without allowing the second refrigerant to pass through when the pressure of the second refrigerant is equal to or higher than a specified value. On the other hand, the constant pressure valve 55 is configured to be in an open state when the pressure of the second refrigerant is less than a specified value. That is, the constant pressure valve 55 allows the second refrigerant to pass when the pressure of the second refrigerant is less than a specified value. FIG. 2 shows an example of a state in which the pressure of the second refrigerant is less than a specified value, so the constant pressure valve 55 is in an open state. The constant pressure valve 55 includes, for example, a diaphragm. Note that the constant pressure valve 55 may be configured to be in a closed state when the pressure of the second refrigerant exceeds a specified value, and to be in an open state when the pressure of the second refrigerant is below a specified value.

In this embodiment, when the liquid refrigerant in the accumulator 21 is sufficiently evaporated and the liquid level Sf1 is lowered, the pressure of the second refrigerant in the heat pipe circuit 50 increases. Thereby, the refrigeration cycle device 100 suppresses the transfer of thermal energy generated on the compressor 10 side to the accumulator 21 side when no liquid refrigerant to be evaporated remains in the accumulator 21. . Below, it will be explained that the pressure of the second refrigerant in the heat pipe circuit 50 decreases as the liquid level Sf1 decreases.

The second refrigerant in the heat pipe circuit 50 repeats evaporation and condensation and circulates in the circulation flow path L2. The second refrigerant evaporated in the heat absorption part 51E is condensed in the heat radiation part 51D immediately after passing through the gas phase flow path 50G. Further, the second refrigerant condensed in the heat radiation part 51D is evaporated in the heat absorption part 51E immediately after passing through the liquid phase flow path 50L. That is, the temperature of the second refrigerant in the heat pipe circuit 50 is constant, being the saturation temperature T, regardless of the state of the second refrigerant.

FIG. 4 is a diagram for explaining the pressure increase of the second refrigerant using a Ph diagram (Mollier diagram). The saturation temperature T is shown on the Ph diagram. The second refrigerant moves on a line indicated as the saturation temperature T by exchanging heat between the heat absorption part 51E and the heat radiation part 51D. On the line indicated as the saturation temperature T, the state of the second refrigerant moves from left to right by evaporating in the heat absorption part 51E, and from right to left by condensing in the heat radiation part 51D.

On the right side of FIG. 4, the formulas Qh=Kh×(Th−T) and Qc=Kc×(T−Tc) are shown, which indicate the amount of heat transfer Qh in the heat absorbing portion 51E and the amount Qc of heat transfer in the heat radiating portion 51D. The amount of heat transfer Qh is the value obtained by subtracting the saturation temperature T from the temperature Th of the first refrigerant in the compressor 10 multiplied by the heat passage rate Kh between the second refrigerant and the first refrigerant in the heat absorption section 51E. becomes. On the other hand, the heat transfer amount Qc is calculated by multiplying the value obtained by subtracting the temperature Tc of the first refrigerant in the accumulator 21 from the saturation temperature T by the heat transfer rate Kc between the second refrigerant and the first refrigerant in the heat radiation part 51D. will be the value.

In the heat pipe circuit 50, the amount of heat transfer Qh and the amount of heat transfer Qc are the same, so that the second refrigerant in the circulation flow path L2 circulates stably. FIG. 5 is a diagram for explaining the internal structure of the heat pipe circuit 50 when no liquid refrigerant to be evaporated remains in the accumulator 21. FIG. 5 shows a state in which the liquid refrigerant in the accumulator 21 has sufficiently evaporated and the position of the liquid level Sf1 has become lower than the heat radiation part 51D.

If the position of the liquid level Sf1 becomes lower than the heat radiating part 51D, the target for heat exchange with the second refrigerant in the heat radiating part 51D changes from the first refrigerant in the liquid state in the accumulator 21 to the first refrigerant in the gas state. change. That is, the heat transfer rate Kc shown in FIG. 4 decreases. If the heat transfer rate Kc decreases, the amount of heat transfer Qc will decrease, but the circulation within the heat pipe circuit 50 balances the amount of heat transfer Qc and the amount of heat transfer Qh to be the same. Since the temperature Th and heat transfer rate Kh of the gaseous first refrigerant on the compressor 10 side do not change due to the decrease in the liquid level Sf1 in the accumulator 21, in order to balance the amount of heat transfer Qc and the amount of heat transfer Qh, The saturation temperature T increases. In other words, as the saturation temperature T increases, the amount of heat transfer Qc and the amount of heat transfer Qh become the same value. As shown in FIG. 4, for example, the saturation temperature T rises to the saturation temperature Ta. Thereby, the pressure of the second refrigerant increases from pressure P to pressure Pa.

Based on the increase in the pressure within the heat pipe circuit 50, the constant pressure valve 55 enters the closed state. That is, the circulation of the second refrigerant within the heat pipe circuit 50 is stopped. In this embodiment, the prescribed pressure value for the constant pressure valve 55 to be in the closed state is any value between pressure P and pressure Pa.

As described above, in the refrigeration cycle device 100 according to the present embodiment, when the position of the liquid level Sf1 changes to a position lower than the heat radiation part 51D, the pressure in the heat pipe circuit 50 increases, and the constant pressure valve 55 is brought into the closed state. becomes. That is, in the refrigeration cycle device 100, the heat of the first refrigerant in a gas state on the compressor 10 side is transferred to the first refrigerant in a liquid state on the accumulator 21 side by circulating the second refrigerant in the heat pipe circuit 50. is suppressed. As a result, in the refrigeration cycle device 100 that heats the accumulator 21 using thermal energy from the compressor 10 side without using external energy, if no liquid refrigerant to be evaporated remains in the accumulator 21. In other words, it is possible to suppress the thermal energy generated on the compressor 10 side from being transmitted to the accumulator 21 side.

Further, after the constant pressure valve 55 is in the closed state, for a certain period of time until the equilibrium state is reached, the second refrigerant is condensed in the heat radiation part 51D, and the second refrigerant is evaporated in the heat absorption part 51E. That is, as shown in FIG. 5, the liquid level Sf2 rises and the liquid level Sf3 falls. When the equilibrium state is reached, the liquid level Sf2 and the liquid level Sf3 are held at fixed positions, and the heat pipe circuit 50 no longer absorbs or radiates heat. After reaching the equilibrium state, if the amount of liquid refrigerant remaining in the accumulator 21 increases again and the position of the liquid surface Sf1 becomes higher than the position of the heat radiation part 51D, the heat transfer rate Kc increases and the heat pipe circuit The pressure within 50 decreases. As a result, the constant pressure valve 55 becomes open.

As described above, in this embodiment, the constant pressure valve 55, which changes the open state and closed state according to a prescribed value between the pressure P and the pressure Pa, is operated by liquid phase flow without electrical control. By providing it on the path 50L, it is possible to switch between starting and stopping the circulation of the heat pipe circuit 50. That is, if the liquid refrigerant to be evaporated remains in the accumulator 21, the heat pipe circuit 50 heats the liquid refrigerant in the accumulator 21 using thermal energy on the compressor 10 side, and causes the liquid refrigerant to evaporate in the accumulator 21. If the target liquid refrigerant is not present, thermal energy on the compressor 10 side is not transferred.

Embodiment 2.
In the refrigeration cycle device 100 of the first embodiment, a configuration has been described in which heat exchange is performed using the rectangular loop heat pipe circuit 50. As explained with reference to FIG. 5, after the constant pressure valve 55 is closed, the liquid level Sf2 rises. However, when the liquid level Sf2 rises to the liquid level Sf4 shown in FIG. 5, the second refrigerant in the liquid state can flow backward through the gas phase flow path 50G. That is, the second refrigerant in a liquid state may flow into the heat absorption section 51E from the gas phase flow path 50G. More specifically, the second refrigerant in a liquid state flows backward from the heat radiation part 51D to the heat absorption part 51E on the negative side of the X-axis of the gas phase flow path 50G, and on the positive side of the X-axis of the gas phase flow path 50G. The second refrigerant in a gas state moves from the heat absorption part 51E to the heat radiation part 51D. If such a backflow of the second refrigerant in a liquid state occurs, circulation of the second refrigerant may occur in the gas phase flow path 50G. That is, heat exchange using the second refrigerant is restarted.

In Embodiment 2, a configuration of a heat pipe circuit 50A that suppresses backflow of the second refrigerant in a liquid state will be described. In addition, in the refrigeration cycle apparatus 100 of Embodiment 2, description is not repeated about the structure which overlaps with the refrigeration cycle apparatus 100 of Embodiment 1.

FIG. 6 is a diagram for explaining the internal structure of the heat pipe circuit 50A in the second embodiment. A heat pipe circuit 50A in the second embodiment has a shape as shown in FIG. In the second embodiment, the heat radiating section 51D is arranged at a position lower than the position of the heat absorbing section 51E. The liquid phase flow path 50L includes a conveying section 60 provided between the constant pressure valve 55 and the heat absorption section 51E in the circulation flow path L2. The transport section 60 moves the second refrigerant that has passed through the constant pressure valve 55 to the heat absorption section 51E by capillary force. That is, the conveyance unit 60 conveys the second refrigerant in a vertically upward direction. The conveying section in the second embodiment includes a porous body for generating capillary action.

As shown in FIG. 6, the heat radiation part 51D has a length D4 in the X-axis direction parallel to the liquid surface Sf1. Moreover, the heat radiation part 51D has a length D3 with respect to the Z-axis direction which is the normal direction to the liquid surface Sf1. In the example of FIG. 2, length D4 is longer than length D3.

FIG. 7 is a diagram for explaining the internal structure of the heat pipe circuit 50A when no liquid refrigerant to be evaporated remains in the accumulator 21 in the second embodiment. In FIG. 7, the position of the liquid level Sf1 is lower than the position of the heat radiation part 51D. As a result, the pressure within the heat pipe circuit 50A increases, and the constant pressure valve 55 is switched to the closed state.

As described above, after the constant pressure valve 55 is in the closed state, for a certain period of time until the equilibrium state is reached, the second refrigerant is condensed in the heat radiation part 51D, and the second refrigerant is evaporated in the heat absorption part 51E. . In the second embodiment as well, the liquid level Sf2 rises, but since the heat radiation part 51D is arranged at a position lower than the position of the heat absorption part 51E, the second refrigerant condensed in the heat radiation part 51D flows backward. equilibrium is reached by. Thereby, in the refrigeration cycle device 100 of the second embodiment, after the constant pressure valve 55 is in the closed state, it is possible to suppress the liquid level Sf2 on the heat radiating part 51D side from rising and the second refrigerant flowing backward.

Further, as shown in FIG. 6, in the heat dissipation portion 51D of the second embodiment, the length D4 parallel to the liquid surface Sf1 is longer than the length D3 in the Z-axis direction. Comparing FIG. 3 of Embodiment 1 and FIG. 6 of Embodiment 2, when the liquid level Sf1 gradually decreases due to evaporation of the second refrigerant, the example of FIG. The liquid level Sf1 reaches the upper part of the heat radiation part 51D earlier than in the example. When the liquid level Sf1 is located between the upper and lower parts of the heat radiating part 51D, heat exchange cannot be performed with the liquid refrigerant of the accumulator 21 in the heat radiating part 51D, which is located higher than the liquid level Sf1. . In the configuration shown in FIG. 6, it takes a long period from when the liquid level Sf1 starts to decrease until it reaches the upper part of the heat radiating part 51D, and during that period, the liquid refrigerant in the accumulator 21 is heated using the entire heat radiating part 51D. can be evaporated. That is, compared to the example of FIG. 3, in the example of FIG. 6, the period required to evaporate the liquid refrigerant in the accumulator 21 is shorter.

As described above, in the refrigeration cycle device 100 according to the second embodiment, the constant pressure valve 55, which changes the open state and the closed state according to the pressure within the heat pipe circuit 50A, is connected to the liquid phase flow path without electrical control. By providing it on the heat pipe circuit 50L, it is possible to switch between starting and stopping the circulation of the heat pipe circuit 50A. That is, if the liquid refrigerant to be evaporated remains in the accumulator 21, the heat pipe circuit 50A heats the liquid refrigerant in the accumulator 21 using thermal energy on the compressor 10 side, and causes the liquid refrigerant to evaporate in the accumulator 21. If there is no target liquid refrigerant, no thermal energy is transferred from the compressor 10 side.

[Modified example]
In the refrigeration cycle apparatus 100 of the first embodiment, the configuration has been described in which the second refrigerant is transported from the constant pressure valve 55 to the heat absorption section 51E by the transport section 60 including a porous body. However, the transportation of the second refrigerant by the transportation unit 60 is not limited to porous bodies. In the second embodiment, an example will be described in which the pipe diameter of the transport section 60A is reduced.

FIG. 8 is a diagram for explaining a modification of the internal structure of the heat pipe circuit 50A in the second embodiment. As shown in FIG. 8, the pipe diameter Td1 of the transport section 60A is smaller than the pipe diameter Td2 of the gas phase flow path 50G. In other words, the tube diameter Td1 is smaller than the tube diameter Td2. The tube diameter Td1 is a tube diameter sufficient to cause the second refrigerant to rise due to capillarity. Thereby, also in the modified refrigeration cycle device 100, the second refrigerant can be transported from the constant pressure valve 55 to the heat absorption section 51E. Note that the transport unit 60A is not limited to a mechanism that transports the second refrigerant using capillary phenomenon, but can transport the second refrigerant using a drive mechanism whose driving power is smaller than the power consumption for heating the liquid refrigerant in the accumulator 21. May be transported.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that equivalent meanings and all changes within the scope of the claims are included.

10 compressor, 10S, 21S space, 11 shell, 12 rotor, 13 stator, 14 shaft, 15 compression mechanism, 16 discharge hole, 17 motor, 20 first heat exchanger, 21 accumulator, 30 expansion valve, 40 second heat Exchanger, 45 four-way valve, 50, 50A heat pipe circuit, 50G gas phase flow path, 50L, 60L liquid phase flow path, 51D heat radiation section, 51E heat absorption section, 55 constant pressure valve, 60, 60A transport section, 100 refrigeration cycle device D direction, D1 to D4 length, Df1 difference, F1, F2 blower, Kc, Kh heat transfer rate, L1, L2 circulation flow path, P, Pa pressure, P1, P2 extension piping, P3, P4, P5 piping, Qc , Qh amount of heat transfer, Sf1 to Sf4 liquid level, T, Ta saturation temperature, Tc, Th temperature, Td1, Td2 pipe diameter.

Claims

A refrigeration cycle device,
a compressor;
a first heat exchanger;
a pressure reducing device;
a second heat exchanger;
a first circulation flow path that connects the compressor, the first heat exchanger, the pressure reduction device, and the second heat exchanger and circulates the first refrigerant;
an accumulator provided on the refrigerant suction side of the compressor;
comprising a heat pipe circuit connecting the compressor and the accumulator,
The heat pipe circuit is
a loop-type second circulation flow path that circulates the second refrigerant;
an endothermic part that absorbs heat from the first refrigerant in the compressor;
a heat radiating part that radiates heat to the first refrigerant in the accumulator;
a constant pressure valve capable of cutting off circulation of the second refrigerant;
The second circulation flow path is
a gas phase flow path for passing the second refrigerant in a gaseous state;
a liquid phase flow path for passing the second refrigerant in a liquid state,
The constant pressure valve is
provided in the liquid phase flow path,
It is in a closed state when the pressure of the second refrigerant is equal to or higher than a specified value,
A refrigeration cycle device that is in an open state when the pressure of the second refrigerant is less than a specified value.
The refrigeration cycle device according to claim 1, wherein the heat radiation part is located at a position lower than the position of the heat absorption part.
The liquid phase flow path includes a conveying part provided between the constant pressure valve and the heat absorption part in the second circulation flow path,
The refrigeration cycle device according to claim 2, wherein the transport section moves the second refrigerant from the constant pressure valve to the heat absorption section by capillary force.
The refrigeration cycle device according to claim 3, wherein the transport section includes a porous body.
The refrigeration cycle device according to claim 3, wherein the diameter of the transport section is smaller than the diameter of the gas phase flow path.
A length of the heat radiating section in a first direction parallel to the liquid surface of the first refrigerant is longer than a length of the heat radiating section in a second direction that is a normal direction to the liquid surface of the first refrigerant. The refrigeration cycle device according to any one of claims 1 to 3.
The refrigeration cycle device according to any one of claims 1 to 6, wherein the first refrigerant or the second refrigerant is a natural refrigerant.
The refrigeration cycle device according to claim 1, wherein the first refrigerant and the second refrigerant are the same type of refrigerant.