CN116783433A

CN116783433A - Refrigeration cycle device

Info

Publication number: CN116783433A
Application number: CN202180087848.0A
Authority: CN
Inventors: 行德骏哉; 门胁仁隆; 坂本伸英
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2021-01-05
Filing date: 2021-01-05
Publication date: 2023-09-19
Also published as: US20240019186A1; EP4276387A4; JPWO2022149188A1; EP4276387A1; JP7427116B2; WO2022149188A1

Abstract

At the time of heating start, the control device (10) turns on the 1 st four-way valve (6) and turns off the 2 nd four-way valve (7), so that the refrigeration cycle device (100) forms a flow path through which the refrigerant passes through the compressor (1), the load side heat exchanger (3), the 1 st expansion valve (4), the heat source side heat exchanger (2), and the accumulator (8A) and returns to the compressor (1), and at the time of heating operation, the control device (10) turns on the 1 st four-way valve (6) and turns on the 2 nd four-way valve (7), and thereby the refrigeration cycle device (100) forms a flow path through which the refrigerant passes through the compressor (1), the load side heat exchanger (3), the 1 st expansion valve (4), the receiver (8B), and the heat source side heat exchanger (2) returns to the compressor (1).

Description

Refrigeration cycle device

Technical Field

The present disclosure relates to a refrigeration cycle apparatus.

Background

Conventionally, there is a refrigeration cycle apparatus including a refrigerant circuit in which a refrigerant circulates. Patent document 1 discloses a refrigerant circuit including: the refrigerant container functions as an accumulator (liquid separator) until a predetermined time elapses from the time of heating start, and after the predetermined time elapses, the refrigerant container functions as a receiver (receiver).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 10-259963

Disclosure of Invention

Problems to be solved by the invention

In the conventional refrigeration cycle apparatus, switching between the accumulator (liquid separator) and the receiver (liquid receiver) is performed by controlling the 1 st flow path switching means and the 2 nd flow path switching means. Since the 1 st flow path switching means and the 2 nd flow path switching means are each constituted by 3 solenoid valves, the control becomes complicated and the device becomes large.

An object of the present disclosure is to provide a small refrigeration cycle device that can easily perform switching control between a liquid separator and a liquid receiver.

Means for solving the problems

The refrigeration cycle apparatus of the present disclosure is a refrigeration cycle apparatus in which a refrigerant circulates. A refrigeration cycle device is provided with: a compressor; a 1 st heat exchanger; a 2 nd side heat exchanger; a 1 st flow control valve; a 1 st four-way valve that switches a flow path of a refrigerant by switching states between a 1 st state and a 2 nd state; a 2 nd four-way valve that switches a flow path of the refrigerant by switching states between a 3 rd state and a 4 th state; a refrigerant container; and a control device that controls the 1 st four-way valve and the 2 nd four-way valve. At the time of heating start, the control device sets the 1 st four-way valve to the 1 st state and sets the 2 nd four-way valve to the 4 th state, thereby forming a flow path for the refrigerant to return to the compressor through the compressor, the 2 nd side heat exchanger, the 1 st flow control valve, the 1 st heat exchanger and the refrigerant container, and at the time of heating operation, the control device sets the 1 st four-way valve to the 1 st state and sets the 2 nd four-way valve to the 3 rd state, thereby forming a flow path for the refrigerant to return to the compressor through the compressor, the 2 nd side heat exchanger, the 1 st flow control valve, the refrigerant container and the 1 st heat exchanger.

Effects of the invention

According to the present disclosure, a small refrigeration cycle device that can easily perform switching control between a liquid separator and a liquid reservoir can be provided.

Drawings

Fig. 1 is a diagram showing a refrigeration cycle apparatus when the operation of embodiment 1 is stopped.

Fig. 2 is a flowchart showing a flow of control at the time of operation stop in embodiment 1.

Fig. 3 is a simplified diagram of the refrigeration cycle apparatus when the operation of embodiment 1 is stopped.

Fig. 4 is a view showing a refrigerant container.

Fig. 5 is a diagram showing a refrigeration cycle apparatus at the time of heating start-up in embodiment 1.

Fig. 6 is a flowchart showing a flow of control at the time of heating start in embodiment 1.

Fig. 7 is a simplified diagram of the refrigeration cycle apparatus at the time of heating start-up in embodiment 1.

Fig. 8 is a diagram showing a refrigeration cycle apparatus in the heating operation of embodiment 1.

Fig. 9 is a flowchart showing a flow of control during heating operation in embodiment 1.

Fig. 10 is a simplified diagram of the refrigeration cycle apparatus in the heating operation of embodiment 1.

Fig. 11 is a diagram showing a refrigeration cycle apparatus at the time of start-up of cooling in embodiment 1.

Fig. 12 is a flowchart showing a flow of control at the time of start-up of cooling in embodiment 1.

Fig. 13 is a simplified diagram of the refrigeration cycle apparatus at the time of start-up of cooling in embodiment 1.

Fig. 14 is a diagram showing the refrigeration cycle apparatus when the operation of embodiment 2 is stopped.

Fig. 15 is a simplified diagram of the refrigeration cycle apparatus at the time of heating start-up according to embodiment 2.

Fig. 16 is a simplified diagram of the refrigeration cycle apparatus in the heating operation of embodiment 2.

Fig. 17 is a simplified diagram of the refrigeration cycle apparatus at the time of start-up of cooling in embodiment 2.

Detailed Description

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the embodiments described below, when the number, and the like are mentioned, the scope of the present disclosure is not necessarily limited by the number, and the like, except when the description is particularly given. The same reference numerals are given to the same or corresponding components, and the description thereof may not be repeated. The case where the structures in the embodiments are used in appropriate combination is expected from the beginning.

Embodiment 1.

Fig. 1 is a diagram showing a refrigeration cycle apparatus 100 when the operation of embodiment 1 is stopped. Fig. 2 is a flowchart showing a flow of control at the time of operation stop in embodiment 1. Fig. 3 is a simplified diagram of the refrigeration cycle apparatus 100 when the operation of embodiment 1 is stopped. The drawings described below functionally show the connection relationship and arrangement structure of the respective devices in the refrigeration cycle apparatus 100, and do not necessarily show the arrangement in the physical space.

Structure of refrigeration cycle device 100

A refrigeration cycle apparatus 100 according to embodiment 1 will be described. As shown in fig. 1, the refrigeration cycle apparatus 100 includes a compressor 1, a heat source side heat exchanger 2 as a 1 st heat exchanger, a load side heat exchanger 3 as a 2 nd heat exchanger, a 1 st expansion valve 4, a 2 nd expansion valve 5, a 1 st four-way valve 6, a 2 nd four-way valve 7, a refrigerant container 8, and a control device 10.

The heat source side heat exchanger 2 exchanges heat between air and the refrigerant using a fan not shown. The load side heat exchanger 3 is a plate heat exchanger that exchanges heat with a heat medium such as water or brine. The use side piping of the load side heat exchanger 3 is connected to a pump, a heat exchanger, and a fan, which are not shown. The 1 st expansion valve 4 and the 2 nd expansion valve 5 are electronically controlled expansion valves (LEV: linear Expansion Valve; linear expansion valves). In the drawings, the 1 st expansion valve 4 is denoted LEV1, and the 2 nd expansion valve 5 is denoted LEV2. The 1 st expansion valve 4 and the 2 nd expansion valve 5 function as flow control valves for adjusting the flow rate of the refrigerant. In the following description, the 1 st expansion valve 4 may be referred to as LEV1, and the 2 nd expansion valve 5 may be referred to as LEV2.

The 1 st four-way valve 6 has a 1 st port P1, a 2 nd port P2, a 3 rd port P3, and a 4 th port P4. The 2 nd four-way valve 7 has a 5 th port P5, a 6 th port P6, a 7 th port P7, and an 8 th port P8.

The control device 10 is connected to the compressor 1, the 1 st expansion valve 4, the 2 nd expansion valve 5, the 1 st four-way valve 6, the 2 nd four-way valve 7, various sensors, and the like. The control device 10 adjusts the flow rate of the refrigerant by controlling the opening degrees of the 1 st expansion valve 4 and the 2 nd expansion valve 5. The control device 10 switches the flow path of the refrigerant by controlling switching between the ports of the 1 st four-way valve 6 and the 2 nd four-way valve 7.

The 1 st four-way valve 6 is configured to be switchable between a 1 st state in which the 1 st port P1 communicates with the 2 nd port P2 and the 3 rd port P3 communicates with the 4 th port P4 and a 2 nd state in which the 1 st port P1 communicates with the 3 rd port P3 and the 2 nd port P2 communicates with the 4 th port P4. The 1 st four-way valve 6 is controlled to be either one of an on state as a 1 st state and an off state as a 2 nd state according to the control of the control device 10.

The 2 nd four-way valve 7 is configured to be switchable between a 3 rd state in which the 5 th port P5 communicates with the 7 th port P7 and the 6 th port P6 communicates with the 8 th port P8 and a 4 th state in which the 5 th port P5 communicates with the 6 th port P6 and the 7 th port P7 communicates with the 8 th port P8. The 2 nd four-way valve 7 is controlled to be either one of an on state as a 3 rd state and an off state as a 4 th state according to the control of the control device 10.

The on state is a state in which the 1 st four-way valve 6 or the 2 nd four-way valve 7 is energized. The off state is a state in which the 1 st four-way valve 6 or the 2 nd four-way valve 7 is not energized. The control device 10 switches between the cooling operation and the heating operation by switching the states of the 1 st four-way valve 6 and the 2 nd four-way valve 7. The refrigerant container 8 functions as an accumulator (liquid separator) for separating gas from refrigerant or a receiver (liquid receiver) for storing liquefied refrigerant according to the operation state of the refrigeration cycle device 100.

< regarding when operation is stopped >

In the refrigeration cycle apparatus 100, when the operation shown in fig. 1 is stopped, the 1 st four-way valve 6 is turned on, and the 2 nd four-way valve 7 is turned off. In the refrigeration cycle apparatus 100 at the time of the stop of the operation, the refrigerant container 8 functions as an accumulator.

As shown in fig. 2, when the operation is stopped, the control device 10 executes the following processing. The control device 10 controls the compressor 1 to operate at the lowest frequency (step S11). In the refrigeration cycle apparatus 100, the minimum operating differential pressure for operating the valve stably is ensured at the time of switching the state of the 2 nd four-way valve 7 by the process of step S11. After step S11, the control device 10 reduces the valve opening degree in order to reduce the pressure of the LEV1 serving as the 1 st expansion valve 4 (step S12). After step S12, the control device 10 fully opens LEV2 as the 2 nd expansion valve 5 (step S13).

After step S13, the control device 10 determines whether or not the 2 nd four-way valve 7 is in the on state (step S14). When it is determined in step S14 that the 2 nd four-way valve 7 is in the off state (no in step S14), the control device 10 stops the operation of the compressor 1 (step S16), and ends the process. When it is determined in step S14 that the 2 nd four-way valve 7 is in the on state (yes in step S14), the control device 10 controls the 2 nd four-way valve 7 from the on state to the off state (step S15). The control device 10 executes the processing of step S16 after step S15, and then ends the processing.

When the operation is stopped, the control device 10 does not execute the process of determining whether the state of the 1 st four-way valve 6 is the on state or the off state. The 1 st four-way valve 6 can use the refrigerant container 8 as an accumulator, whether in an on state or an off state.

When the control device 10 turns on the 1 st four-way valve 6 and turns off the 2 nd four-way valve 7, the refrigeration cycle apparatus 100 turns into the refrigerant circuit as shown in fig. 3 if the refrigerant circuit is described by omitting the 1 st four-way valve 6 and the 2 nd four-way valve 7. The refrigeration cycle apparatus 100 shown in fig. 3 is a refrigerant circuit in which a compressor 1, a load side heat exchanger 3, a 1 st expansion valve 4, a heat source side heat exchanger 2, a 2 nd expansion valve 5, and an accumulator 8A are connected in this order. At the time of the operation stop, the refrigerant container 8 is used as an accumulator.

< about refrigerant container 8 >)

Fig. 4 is a diagram showing the refrigerant container 8. The refrigerant container 8 includes an inflow pipe 8a, an outflow pipe 8b, an oil return hole 8c, and a suction pipe 8d. The refrigerant container 8 stores a mixed liquid L of oil and refrigerant. When the refrigerant container 8 functions as an accumulator, gas in the gas-liquid two-phase refrigerant is separated to accumulate the liquid refrigerant.

The refrigerant container 8 returns oil from the oil return hole 8c in the low flow area shown on the left side of fig. 4, thereby preventing liquid refrigerant from flowing back to the compressor 1 to cause a decrease in capacity and reliability of the compressor 1. The diameter of the oil return hole 8c is preferably reduced to prevent occurrence of the return liquid. In the high flow rate region shown on the right side of fig. 4, the refrigerant container 8 returns oil only through the oil return hole 8c, and the amount of return oil is insufficient with respect to the amount of discharge oil of the compressor 1, so that the amount of return oil is ensured by returning oil from the suction pipe 8d.

When functioning as a receiver, the refrigerant container 8 accumulates the refrigerant discharged from the heat exchanger functioning as a condenser, thereby appropriately securing the amount of refrigerant that has passed to the heat exchanger functioning as an evaporator.

< related to heating start time >)

Fig. 5 is a diagram showing the refrigeration cycle apparatus 100 at the time of heating start-up in embodiment 1. Fig. 6 is a flowchart showing a flow of control at the time of heating start in embodiment 1. Fig. 7 is a simplified diagram of the refrigeration cycle apparatus 100 at the time of heating start-up according to embodiment 1.

In the refrigeration cycle apparatus 100, at the time of the heating start shown in fig. 5, the 1 st four-way valve 6 is turned on, and the 2 nd four-way valve 7 is turned off. In the refrigeration cycle apparatus 100 at the time of heating start, the refrigerant container 8 functions as an accumulator.

As shown in fig. 6, at the time of the warm-up, the control device 10 performs the following processing. The control device 10 controls the compressor 1 to start (step S21). After step S21, the control device 10 reduces the valve opening degree in order to reduce the pressure of the LEV1 serving as the 1 st expansion valve 4 (step S22). After step S22, the control device 10 fully opens LEV2 as the 2 nd expansion valve 5 (step S23).

After step S23, the control device 10 determines whether or not the 1 st four-way valve 6 is in the on state (step S24). When it is determined in step S24 that the 1 st four-way valve 6 is in the on state (yes in step S24), the control device 10 ends the process. When it is determined in step S24 that the 1 st four-way valve 6 is in the off state (no in step S24), the control device 10 controls the 1 st four-way valve 6 from the off state to the on state (step S25), and ends the process.

When the control device 10 turns on the 1 st four-way valve 6 and turns off the 2 nd four-way valve 7, the refrigeration cycle apparatus 100 turns into a refrigerant circuit as shown in fig. 7 if the refrigerant circuit is described by omitting the 1 st four-way valve 6 and the 2 nd four-way valve 7. The refrigeration cycle apparatus 100 shown in fig. 7 is a refrigerant circuit that forms a flow path through which the refrigerant passes through the compressor 1, the load side heat exchanger 3, the 1 st expansion valve 4, the heat source side heat exchanger 2, the 2 nd expansion valve 5, and the accumulator 8A and returns to the compressor 1. The refrigerant container 8 is used as an accumulator at the time of warm start.

In the refrigeration cycle apparatus 100 at the time of heating start, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the load side heat exchanger 3. Then, the liquid refrigerant condensed in the load side heat exchanger 3 is depressurized by the 1 st expansion valve 4. Then, the decompressed liquid refrigerant is evaporated in the heat source side heat exchanger 2. Then, the gas-liquid two-phase refrigerant evaporated in the heat source side heat exchanger 2 passes through the 2 nd expansion valve 5, is processed in the accumulator 8A, and is then sucked into the compressor 1.

< related to heating operation >)

Fig. 8 is a diagram showing the refrigeration cycle apparatus 100 in the heating operation of embodiment 1. Fig. 9 is a flowchart showing a flow of control during heating operation in embodiment 1. Fig. 10 is a simplified diagram of the refrigeration cycle apparatus 100 in the heating operation of embodiment 1.

In the refrigeration cycle apparatus 100, during the heating operation shown in fig. 8, the 1 st four-way valve 6 is turned on, and the 2 nd four-way valve 7 is turned on. In the refrigeration cycle apparatus 100 during the heating operation, the refrigerant container 8 functions as a receiver.

As shown in fig. 9, at the time of the heating operation, the control device 10 executes the following processing. The control device 10 determines whether or not the degree of superheat (SH: super Heat) of the refrigerant at the inlet of the accumulator 8A at the time of heating start shown in fig. 7 is 2 ℃ or higher (step S31). Step S31 is a process at the time of heating start before starting the heating operation. The degree of superheat refers to the temperature difference between the superheated steam and the dry saturated steam. The temperature of the superheated steam is measured by a temperature sensor not shown. When the liquid refrigerant returns, the liquid refrigerant is sent to the compressor 1, and therefore, the temperature of the refrigerant discharged from the compressor 1 decreases, and accordingly, the degree of superheat decreases. In the refrigeration cycle apparatus 100, a reference value of the degree of superheat is set in advance, and if the degree of superheat is lower than the reference value, it is determined that the liquid return has occurred.

When it is determined in step S31 that SH is not equal to or greater than 2 ℃ (no in step S31), control device 10 repeats the process in step S31. When it is determined in step S31 that SH is not less than 2 ℃ (yes in step S31), control device 10 repeats the process of step S31.

When it is determined in step S31 that SH is not less than 2 ℃ (yes in step S31), the control device 10 controls the fourth-way valve 7 from the off state to the on state (step S32). After step S32, the control device 10 reduces the valve opening degree in order to reduce the pressure of the LEV1 serving as the 1 st expansion valve 4 (step S33). After step S33, the control device 10 reduces the valve opening degree to reduce the pressure of the LEV2 serving as the 2 nd expansion valve 5 (step S34), and ends the process.

In the conventional refrigeration cycle apparatus, when the temperature of the external air is low (for example, -20 ℃ of the external air), a phenomenon (refrigerant immersion) occurs in which the refrigerant accumulates in the heat source side heat exchanger, and the liquid refrigerant may flow to the compressor immediately after the heating start, so that it is not possible to increase the compressor frequency until the steady operation is performed.

In the refrigeration cycle apparatus 100, the refrigerant container 8 functions as the accumulator 8A at the time of heating start, and therefore, by accumulating the refrigerant in the refrigerant container 8, it is possible to prevent the liquid refrigerant from flowing into the compressor 1. The refrigeration cycle apparatus 100 can perform the steady-state heating operation by increasing the frequency of the compressor 1 on the condition that the degree of Superheat (SH) satisfies SH not less than 2 ℃ by the process of step S31, and therefore can shorten the heating start time in low-temperature outside air.

When the control device 10 turns on the 1 st four-way valve 6 and turns on the 2 nd four-way valve 7, the refrigeration cycle apparatus 100 turns into a refrigerant circuit as shown in fig. 10 if the refrigerant circuit is described by omitting the 1 st four-way valve 6 and the 2 nd four-way valve 7. The refrigeration cycle apparatus 100 shown in fig. 10 is a refrigerant circuit that forms a flow path through which the refrigerant passes through the compressor 1, the load side heat exchanger 3, the 1 st expansion valve 4, the receiver 8B, the 2 nd expansion valve 5, and the heat source side heat exchanger 2 and returns to the compressor 1. The refrigerant container 8 is used as a receiver during heating operation.

In the refrigeration cycle apparatus 100 during the heating operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the load side heat exchanger 3. Then, the liquid refrigerant condensed in the load side heat exchanger 3 is depressurized by the 1 st expansion valve 4. Then, the depressurized liquid refrigerant passes through the receiver 8B, is further depressurized in the 2 nd expansion valve 5, and is evaporated in the heat source side heat exchanger 2. The gas refrigerant evaporated in the heat source side heat exchanger 2 is sucked into the compressor 1.

The amount of refrigerant used in the refrigerant circuit during the heating operation is smaller than the amount of refrigerant used in the refrigerant circuit during the cooling operation. The receiver 8B can store the refrigerant remaining during the heating operation. The control device 10 controls the 1 st expansion valve 4 to adjust the amount of refrigerant stored in the receiver 8B. The capacity of the load side heat exchanger 3 can be ensured by adjusting the amount of refrigerant to be used to an optimal amount.

< about refrigeration start time >)

Fig. 11 is a diagram showing the refrigeration cycle apparatus 100 at the time of start-up of cooling in embodiment 1. Fig. 12 is a flowchart showing a flow of control at the time of start-up of cooling in embodiment 1. Fig. 13 is a simplified diagram of the refrigeration cycle apparatus 100 at the time of start-up of cooling in embodiment 1.

In the refrigeration cycle apparatus 100, at the time of the start of the refrigeration shown in fig. 11, the 1 st four-way valve 6 is turned off, and the 2 nd four-way valve 7 is turned off. In the refrigeration cycle apparatus 100 at the time of start-up of cooling, the refrigerant container 8 functions as an accumulator.

As shown in fig. 12, at the time of refrigerant startup, the control device 10 performs the following processing. The control device 10 controls the compressor 1 to start (step S41). After step S41, the control device 10 reduces the valve opening degree in order to reduce the pressure of the LEV1 serving as the 1 st expansion valve 4 (step S42). After step S42, the control device 10 fully opens LEV2 as the 2 nd expansion valve 5 (step S43).

After step S43, the control device 10 determines whether or not the 1 st four-way valve 6 is in the on state (step S44). When it is determined in step S44 that the 1 st four-way valve 6 is in the off state (no in step S44), the control device 10 ends the process. When it is determined in step S44 that the 1 st four-way valve 6 is in the on state (yes in step S44), the control device 10 controls the 1 st four-way valve 6 from the on state to the off state (step S45), and ends the process.

When the control device 10 turns off the 1 st four-way valve 6 and turns off the 2 nd four-way valve 7, the refrigeration cycle apparatus 100 turns into the refrigerant circuit shown in fig. 13 if the refrigerant circuit is described by omitting the 1 st four-way valve 6 and the 2 nd four-way valve 7. The refrigeration cycle apparatus 100 shown in fig. 13 is a refrigerant circuit that forms a flow path through which the refrigerant passes through the compressor 1, the 2 nd expansion valve 5, the heat source side heat exchanger 2, the 1 st expansion valve 4, the load side heat exchanger 3, and the accumulator 8A and returns to the compressor 1. The refrigerant container 8 is used as an accumulator at the time of a cold start.

In the refrigeration cycle apparatus 100 at the time of start of cooling, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the heat source side heat exchanger 2. Then, the liquid refrigerant condensed in the heat source side heat exchanger 2 is depressurized by the 1 st expansion valve 4. Then, the decompressed liquid refrigerant is evaporated in the load side heat exchanger 3. Then, the gas-liquid two-phase refrigerant evaporated in the load side heat exchanger 3 is treated in the accumulator 8A, and then the gas refrigerant is sucked into the compressor 1.

< about the time of cooling operation >)

The refrigeration cycle apparatus 100 forms the same refrigerant circuit at the time of the cooling operation as at the time of the cooling start. The amount of refrigerant used in the refrigerant circuit during the cooling operation is larger than the amount of refrigerant used in the refrigerant circuit during the heating operation. In the refrigeration cycle apparatus 100 during the cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the heat source side heat exchanger 2. Then, the liquid refrigerant condensed in the heat source side heat exchanger 2 is depressurized by the 1 st expansion valve 4. Then, the decompressed liquid refrigerant is evaporated in the load side heat exchanger 3. Then, the gas-liquid two-phase refrigerant evaporated in the load side heat exchanger 3 is treated in the accumulator 8A, and then the gas refrigerant is sucked into the compressor 1.

Embodiment 2.

Fig. 14 is a diagram showing a refrigeration cycle apparatus 200 at the time of heating start-up in embodiment 2. Fig. 15 is a simplified diagram of the refrigeration cycle apparatus 200 at the time of heating start-up according to embodiment 2. Fig. 16 is a simplified diagram of the refrigeration cycle apparatus 200 in the heating operation of embodiment 2. Fig. 17 is a simplified diagram of the refrigeration cycle apparatus 200 at the time of start-up of cooling in embodiment 2.

Structure of refrigeration cycle device 200

The various devices used in the refrigeration cycle apparatus 200 of embodiment 2 are the same as those used in the refrigeration cycle apparatus 100 of embodiment 1. The refrigeration cycle apparatus 200 is different in the position of the 2 nd expansion valve 5 from the refrigeration cycle apparatus 100. In the refrigeration cycle apparatus 100, the 2 nd expansion valve 5 is located between the 1 st four-way valve 6 and the heat source side heat exchanger 2. In the refrigeration cycle apparatus 200, the 2 nd expansion valve 5 is located between the 1 st four-way valve 6 and the refrigerant container 8.

< related to heating start time >)

When the control device 10 turns on the 1 st four-way valve 6 and turns off the 2 nd four-way valve 7, the refrigeration cycle apparatus 200 turns into a refrigerant circuit as shown in fig. 15 if the refrigerant circuit is described by omitting the 1 st four-way valve 6 and the 2 nd four-way valve 7. The refrigeration cycle apparatus 200 shown in fig. 15 is a refrigerant circuit that forms a flow path through which the refrigerant passes through the compressor 1, the load side heat exchanger 3, the 1 st expansion valve 4, the heat source side heat exchanger 2, the 2 nd expansion valve 5, and the accumulator 8A and returns to the compressor 1. The refrigerant container 8 is used as an accumulator at the time of warm start. The arrangement of the devices of the refrigeration cycle apparatus 200 shown in fig. 15 is the same as the arrangement of the devices of the refrigerant circuit shown in fig. 7.

< related to heating operation >)

When the control device 10 turns on the 1 st four-way valve 6 and turns on the 2 nd four-way valve 7, the refrigeration cycle apparatus 200 turns into a refrigerant circuit as shown in fig. 16 if the refrigerant circuit is described by omitting the 1 st four-way valve 6 and the 2 nd four-way valve 7. The refrigeration cycle apparatus 200 shown in fig. 16 is a refrigerant circuit that forms a flow path through which the refrigerant passes through the compressor 1, the load side heat exchanger 3, the 1 st expansion valve 4, the receiver 8B, the 2 nd expansion valve 5, and the heat source side heat exchanger 2 and returns to the compressor 1. The refrigerant container 8 is used as a receiver during heating operation. The arrangement of the devices of the refrigeration cycle apparatus 200 shown in fig. 16 is the same as the arrangement of the devices of the refrigerant circuit shown in fig. 10.

< about refrigeration start time >)

When the control device 10 turns off the 1 st four-way valve 6 and turns off the 2 nd four-way valve 7, the refrigeration cycle apparatus 200 turns into the refrigerant circuit shown in fig. 17 if the refrigerant circuit is described by omitting the 1 st four-way valve 6 and the 2 nd four-way valve 7. The refrigeration cycle apparatus 200 shown in fig. 17 is a refrigerant circuit that forms a flow path through which the refrigerant passes through the compressor 1, the heat source side heat exchanger 2, the 1 st expansion valve 4, the load side heat exchanger 3, the 2 nd expansion valve 5, and the accumulator 8A and returns to the compressor 1. The refrigerant container 8 is used as an accumulator at the time of a cold start. The refrigeration cycle apparatus 200 shown in fig. 17 has the same function as the refrigerant circuit shown in fig. 13, although the position of the 2 nd expansion valve 5 is different.

< about the time of cooling operation >)

The refrigeration cycle apparatus 200 forms the same refrigerant circuit at the time of the cooling operation as at the time of the cooling start. The amount of refrigerant used in the refrigerant circuit during the cooling operation is larger than the amount of refrigerant used in the refrigerant circuit during the heating operation. In the refrigeration cycle apparatus 200 during the cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the heat source side heat exchanger 2. Then, the liquid refrigerant condensed in the heat source side heat exchanger 2 is depressurized by the 1 st expansion valve 4. Then, the decompressed liquid refrigerant is evaporated in the load side heat exchanger 3. Then, the gas-liquid two-phase refrigerant evaporated in the load side heat exchanger 3 is treated in the accumulator 8A, and then the gas refrigerant is sucked into the compressor 1.

< summary >

The present disclosure relates to a refrigeration cycle apparatus 100 in which a refrigerant circulates. The refrigeration cycle apparatus 100 includes: a compressor 1; a heat source side heat exchanger 2; a load side heat exchanger 3; a 1 st expansion valve 4 as a 1 st flow control valve; a 1 st four-way valve 6 that switches a flow path of the refrigerant by switching a state between an on state as a 1 st state and an off state as a 2 nd state; a 2 nd four-way valve 7 that switches a flow path of the refrigerant by switching a state between an on state as a 3 rd state and an off state as a 4 th state; a refrigerant container 8; and a control device 10 that controls the 1 st four-way valve 6 and the 2 nd four-way valve 7. At the time of heating start, the control device 10 turns on the 1 st four-way valve 6 and turns off the 2 nd four-way valve 7, and thereby the refrigeration cycle apparatus 100 forms a flow path through which the refrigerant passes through the compressor 1, the load side heat exchanger 3, the 1 st expansion valve 4, the heat source side heat exchanger 2, and the refrigerant container 8 functioning as the accumulator 8A and returns to the compressor 1, and at the time of heating operation, the control device 10 turns on the 1 st four-way valve 6 and turns on the 2 nd four-way valve 7, and thereby the refrigeration cycle apparatus 100 forms a flow path through which the refrigerant passes through the compressor 1, the load side heat exchanger 3, the 1 st expansion valve 4, the refrigerant container 8 functioning as the receiver 8B, and the heat source side heat exchanger 2 returns to the compressor 1.

With such a configuration, the refrigeration cycle apparatus 100 can easily switch the refrigerant container 8 between the accumulator 8A as the liquid separator and the receiver 8B as the liquid receiver. Therefore, the refrigeration cycle apparatus 100 can be a small and appropriate refrigeration cycle apparatus according to the operation state by simple control of switching the 1 st four-way valve 6 and the 2 nd four-way valve 7.

Preferably, at the time of the start of cooling, the control device 10 turns off the 1 st four-way valve 6 and turns off the 2 nd four-way valve 7, so that the refrigeration cycle apparatus 100 forms a flow path through which the refrigerant passes through the compressor 1, the heat source side heat exchanger 2, the 1 st expansion valve 4, the load side heat exchanger 3, and the refrigerant container 8 functioning as the accumulator 8A and returns to the compressor 1.

With such a configuration, the refrigeration cycle apparatus 100 can be a small and appropriate refrigeration cycle apparatus according to the operation state by simple control of switching the 1 st four-way valve 6 and the 2 nd four-way valve 7.

Preferably, the refrigerant container 8 is used as the accumulator 8A as a liquid separator for separating liquid and gas contained in the refrigerant at the time of heating start-up and at the time of refrigerant start-up, and is used as the receiver 8B as a liquid reservoir for storing liquid contained in the refrigerant at the time of heating operation.

With such a configuration, the refrigerant container 8 can be switched between the function of the accumulator 8A and the function of the receiver 8B according to the operation state, and therefore, compared with the case where the refrigerant container is separately provided, the refrigeration cycle device can be miniaturized.

Preferably, the refrigeration cycle apparatus 100 further includes a 2 nd expansion valve 5 as a 2 nd flow rate control valve. At the time of start-up of cooling, as shown in fig. 13, the 1 st expansion valve 4 is disposed between the heat source side heat exchanger 2 and the load side heat exchanger 3, and the 2 nd expansion valve 5 is disposed between the compressor 1 and the heat source side heat exchanger 2. More specifically, at the time of the start of cooling, as shown in fig. 11, the 1 st expansion valve 4 is disposed between the 2 nd four-way valve 7 and the load side heat exchanger 3, and the 2 nd expansion valve 5 is disposed between the 1 st four-way valve 6 and the heat source side heat exchanger 2.

With such a configuration, the refrigeration cycle apparatus 100 can set the positions of the 1 st expansion valve 4 and the 2 nd expansion valve 5 to appropriate positions in which the flow rate of the refrigerant can be controlled, depending on the operating state.

Preferably, the refrigeration cycle apparatus 200 further includes a 2 nd expansion valve 5 as a 2 nd flow rate control valve. At the time of start-up of cooling, as shown in fig. 17, the 1 st expansion valve 4 is disposed between the heat source side heat exchanger 2 and the load side heat exchanger 3, and the 2 nd expansion valve 5 is disposed between the load side heat exchanger 3 and the refrigerant container 8 functioning as the accumulator 8A. More specifically, at the time of the start of cooling, as shown in fig. 14, the 1 st expansion valve 4 is disposed between the 2 nd four-way valve 7 and the load side heat exchanger 3, and the 2 nd expansion valve 5 is disposed between the 1 st four-way valve 6 and the refrigerant container 8 functioning as the accumulator 8A.

Preferably, the control device 10 controls the opening degrees of the 1 st expansion valve 4 and the 2 nd expansion valve 5, and the control device 10 sets the opening degree of the 1 st expansion valve 4 smaller than the full opening and sets the opening degree of the 2 nd expansion valve 5 to the full opening as shown in fig. 6 and 12 at the time of heating start and at the time of refrigerant start.

With such a configuration, the refrigeration cycle apparatus 100 can appropriately adjust the opening degrees of the 1 st expansion valve 4 and the 2 nd expansion valve 5 according to the operation state.

Preferably, at the time of the heating operation, as shown in fig. 9, the control device 10 makes the opening degree of the 1 st expansion valve 4 smaller than the full opening, and makes the opening degree of the 2 nd expansion valve 5 smaller than the full opening.

Preferably, at the time of the heating start, as shown in step S31 of fig. 9, when the degree of Superheat (SH) of the suction side of the compressor 1 becomes 2 ℃ or higher, the control device 10 controls the 2 nd four-way valve 7 to be in the on state.

With such a configuration, the refrigeration cycle apparatus 100 can perform the steady-state heating operation by increasing the frequency of the compressor 1 on the condition that the degree of Superheat (SH) satisfies SH not less than 2 ℃.

< modification >

The refrigeration cycle apparatus 100 may be a refrigerant circuit having only the 1 st expansion valve 4 without the 2 nd expansion valve 5.

The load side heat exchanger 3 may be a heat exchanger other than a plate heat exchanger.

The embodiments disclosed herein are examples in all respects and should not be considered as limiting. The scope of the present disclosure is not shown by the description of the above embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

Description of the reference numerals

1: a compressor; 2: a heat source side heat exchanger; 3: a load side heat exchanger; 4: a 1 st expansion valve; 5: a 2 nd expansion valve; 6: a 1 st four-way valve; 7: a 2 nd four-way valve; 8: a refrigerant container; 8A: an energy storage; 8B: a receiver; 8a: an inflow tube; 8b: an outflow tube; 8c: an oil return hole; 8d: a suction pipe; 10: a control device; 100. 200: a refrigeration cycle device; l: a mixed solution; p1: port 1; p2: a 2 nd port; p3: 3 rd port; p4: a 4 th port; p5: a 5 th port; p6: a 6 th port; p7: a 7 th port; p8: 8 th port.

Claims

1. A refrigeration cycle apparatus for circulating a refrigerant, the refrigeration cycle apparatus comprising:

a compressor;

a 1 st heat exchanger;

a 2 nd heat exchanger;

a 1 st flow control valve;

a 1 st four-way valve that switches a flow path of the refrigerant by switching states between a 1 st state and a 2 nd state;

a 2 nd four-way valve that switches a flow path of the refrigerant by switching states between a 3 rd state and a 4 th state;

a refrigerant container; and

a control device for controlling the 1 st four-way valve and the 2 nd four-way valve,

at the time of heating start, the control device sets the 1 st four-way valve to the 1 st state and sets the 2 nd four-way valve to the 4 th state, thereby the refrigeration cycle device forms a flow path for the refrigerant to return to the compressor through the compressor, the 2 nd heat exchanger, the 1 st flow control valve, the 1 st heat exchanger and the refrigerant container,

in the heating operation, the control device sets the 1 st four-way valve to the 1 st state and sets the 2 nd four-way valve to the 3 rd state, whereby the refrigeration cycle device forms a flow path through which the refrigerant passes through the compressor, the 2 nd heat exchanger, the 1 st flow control valve, the refrigerant container, and the 1 st heat exchanger and returns to the compressor.

2. The refrigeration cycle apparatus according to claim 1, wherein,

at the time of start-up of cooling, the control device sets the 1 st four-way valve to the 2 nd state and sets the 2 nd four-way valve to the 4 th state, whereby the refrigeration cycle device forms a flow path through which the refrigerant passes through the compressor, the 1 st heat exchanger, the 1 st flow control valve, the 2 nd heat exchanger, and the refrigerant container to return to the compressor.

3. The refrigeration cycle apparatus according to claim 2, wherein,

the refrigerant container is used as a liquid separator for separating a liquid and a gas contained in the refrigerant at the time of the heating start and at the time of the refrigerant start, and is used as a liquid reservoir for storing the liquid contained in the refrigerant at the time of the heating operation.

4. A refrigeration cycle apparatus according to claim 2 or 3, wherein,

the refrigeration cycle apparatus further includes a 2 nd flow control valve,

when the cooling is started, the 1 st flow control valve is disposed between the 1 st heat exchanger and the 2 nd heat exchanger, and the 2 nd flow control valve is disposed between the compressor and the 1 st heat exchanger.

5. A refrigeration cycle apparatus according to claim 2 or 3, wherein,

the refrigeration cycle apparatus further includes a 2 nd flow control valve,

when the cooling is started, the 1 st flow control valve is disposed between the 1 st heat exchanger and the 2 nd heat exchanger, and the 2 nd flow control valve is disposed between the 2 nd heat exchanger and the refrigerant container.

6. A refrigeration cycle apparatus according to claim 4 or 5, wherein,

the control device controls the opening degrees of the 1 st flow control valve and the 2 nd flow control valve,

the control device sets the opening degree of the 1 st flow control valve smaller than the full opening and sets the opening degree of the 2 nd flow control valve to the full opening at the time of the heating start and at the time of the refrigerant start.

7. The refrigeration cycle apparatus according to claim 6, wherein,

in the heating operation, the control device makes the opening degree of the 1 st flow rate control valve smaller than the full opening, and makes the opening degree of the 2 nd flow rate control valve smaller than the full opening.

8. The refrigeration cycle apparatus according to any one of claims 1 to 7, wherein,

the control device controls the 2 nd four-way valve to the 3 rd state when the degree of superheat of the suction side of the compressor becomes 2 ℃ or higher at the time of the heating start.