A drying device of a rotary coupling compression heat pump and a method for operating the same

Abstract

A rotary coupling compression heat pump drying device and its operation method, comprising: a dehumidification rotary, a four-way reversing valve, a heat pump compressor, a gas-liquid separator, a supply air system, a drying system, a regeneration system, a one-way valve, a liquid storage tank, an evaporator, an electronic expansion valve, a solenoid valve, a heat pump channel and a defrosting auxiliary channel. Compared with the prior art, the dehumidification rotary and the compression heat pump are coupled, the drying effect of the drying device is improved, and the system energy consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of dehumidifying rotors and heat pump drying technology, specifically to a drying device and its operation method using a rotor-coupled compression heat pump. Background Technology

[0002] Material drying is a huge energy-consuming process. According to statistics, the energy consumed in drying accounts for 7%-15% of the country's total energy consumption, while the thermal efficiency is only 25%-50%.

[0003] Heat pump drying units are increasingly widely used in agricultural and industrial product drying, sewage and sludge treatment, and commercial or residential drying equipment. They feature high energy efficiency, low initial investment, high drying quality, wide applicability, no combustion process, and minimal environmental pollution.

[0004] In certain humidity control applications, dehumidifying rotor technology is used to achieve low dew point drying. Moisture in the air is adsorbed by the rotor, reducing its moisture content, while in the regeneration zone, moisture is carried away by high-temperature regeneration air. However, its dehumidification capacity is relatively small, and it consumes a lot of power, resulting in low energy efficiency.

[0005] Traditional heat pump drying equipment primarily transfers heat from the external low-temperature environment to the drying chamber through heat pump circulation and condensation. Its supply air temperature is typically around 50℃ to 80℃, and the relative humidity is around 15% to 40%. However, in some special cases, such as with heat-sensitive materials (food and biological materials), excessively high temperatures can adversely affect their color, nutrition, flavor, and texture. Furthermore, in the drying process of spray paint, to ensure the smoothness of the paint surface and prevent wrinkles and bubbles, there are relatively strict requirements for drying air velocity and drying time.

[0006] Therefore, for the above-mentioned special scenarios, those skilled in the art are committed to providing a new type of drying device that effectively combines the advantages of dehumidifying rotor and compression heat pump. Summary of the Invention

[0007] The purpose of this invention is to provide a drying device and its operation method for a rotary coupling compression heat pump, so as to overcome the above-mentioned shortcomings and deficiencies of the prior art.

[0008] A drying device for a rotary coupled compression heat pump includes: a dehumidifying rotor, a four-way reversing valve, a heat pump compressor, a gas-liquid separator, an air supply system, a drying system, a regeneration system, a one-way valve, a liquid storage tank, an evaporator, an electronic expansion valve, a solenoid valve, a heat pump channel, and a defrosting auxiliary channel. One end of the dehumidifying rotor is connected to the evaporator. The four-way reversing valve is connected to the other end of the dehumidifying rotor, the heat pump compressor, the gas-liquid separator, and the drying system. The heat pump compressor is connected to the gas-liquid separator. The drying system is connected to the one-way valve through the defrosting auxiliary channel. The drying system is connected to the solenoid valve and the one-way valve through the heat pump channel. The regeneration system is connected to the one-way valve. The regeneration system is connected to the liquid storage tank through the defrosting auxiliary channel. The liquid storage tank is connected to the evaporator. The electronic expansion valve is located between the liquid storage tank and the evaporator.

[0009] The dehumidification impeller includes a regeneration air duct and a drying air duct. The air inlet of the drying air duct is connected to the air-side air duct of the evaporator, the air outlet of the drying air duct is connected to the regeneration system, and the air inlet of the regeneration air duct is connected to the drying system.

[0010] The drying system includes: a first condenser and a first electric heater. The first condenser and the first electric heater are respectively connected to the air inlet of the regeneration air duct. The first port on the refrigerant side of the first condenser is connected to the second port of the four-way reversing valve. The second port on the refrigerant side of the first condenser is connected to the solenoid valve, the one-way valve and the regeneration system via the heat pump channel.

[0011] The regeneration system includes: a second condenser and a second electric heater, the second condenser and the second electric heater being connected to the air outlet of the drying air duct respectively, the first port of the refrigerant side of the second condenser being connected to the second port of the refrigerant side of the first condenser via a heat pump channel, the second port of the refrigerant side of the second condenser being connected to the first port of the liquid storage tank, and the second port of the refrigerant side of the second condenser being connected to the second port of the refrigerant side of the first condenser via a defrosting auxiliary channel and a one-way valve.

[0012] The one-way valve includes: a first one-way valve and a second one-way valve, wherein the first one-way valve is connected to a second port on the refrigerant side of the first condenser, and the second one-way valve is connected to a second port on the refrigerant side of the second condenser and a second port on the refrigerant side of the first condenser.

[0013] Furthermore, the air supply system includes a drying air supply fan and a regeneration air supply fan, wherein the drying air supply fan is located in the air duct between the second condenser and the second electric heater, and the regeneration air supply fan is located in the air duct between the first condenser and the first electric heater.

[0014] A method for operating a drying device using a rotary coupling compression heat pump includes the following steps:

[0015] Step 1: Ambient air enters from the air inlet of the drying air duct, and is pre-cooled to the dew point temperature by the action of the evaporator driven by the drying blower. It is then sent into the dehumidification wheel for adsorption and dehumidification. The dried air is heated by the action of the second condenser and sent into the drying room.

[0016] Step 2: The ambient air required for regeneration enters from the air inlet of the regeneration air duct and is heated by the first condenser under the drive of the regeneration blower for the regeneration of the dehumidification wheel.

[0017] Step 3: The second electric heater is used for supplementing the heat and temperature control of the drying air, and the first electric heater is used for supplementing the heat and temperature control of the regenerated air.

[0018] Step 4: By switching the four-way reversing valve and the solenoid valve on and off, the drying device is controlled to switch between normal drying mode and automatic defrosting mode.

[0019] Furthermore, step 1 achieves normal mode operation by switching between a four-way reversing valve and a solenoid valve, including the following steps: the heat pump circulating working fluid, driven by the heat pump compressor, sequentially passes through the four-way reversing valve, the first condenser, the solenoid valve, the first check valve, the second condenser, the liquid receiver, the electronic expansion valve, the evaporator, the four-way reversing valve, the gas-liquid separator, and finally returns to the heat pump compressor suction port.

[0020] Furthermore, step 2 achieves automated defrosting operation mode by switching through a four-way reversing valve, including the following steps: the heat pump circulating working fluid, driven by the heat pump compressor, sequentially passes through the four-way reversing valve, evaporator, electronic expansion valve, liquid receiver, second check valve, first condenser, four-way reversing valve, gas-liquid separator, and finally returns to the heat pump compressor suction port.

[0021] The beneficial effects of this invention are:

[0022] Compared with traditional technologies, this invention improves the drying effect of the drying device while reducing system energy consumption by coupling a dehumidifying impeller with a compression heat pump. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the drying device structure of the dehumidifying rotary coupling compression heat pump of the present invention.

[0024] Figure 2 This is a schematic diagram of the device structure and operating principle of the heat pump cycle of the present invention.

[0025] Figure label:

[0026] Dehumidifying impeller 100, regeneration air duct 110 and drying air duct 120.

[0027] Four-way reversing valve 300, heat pump compressor 200, and gas-liquid separator 400.

[0028] Air supply system 500, drying air supply fan 510 and regeneration air supply fan 520.

[0029] The system includes a drying system 600, a first condenser 610, and a first electric heater 620.

[0030] The regeneration system 700, the second condenser 710, and the second electric heater 720.

[0031] One-way valve 800, first one-way valve 810 and second one-way valve 820.

[0032] Liquid storage tank 900, evaporator 1000, electronic expansion valve 1100, solenoid valve 1200, heat pump channel 1300 and defrosting auxiliary channel 1400. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0034] Figure 1 This is a schematic diagram of the drying device structure of the dehumidifying rotary coupling compression heat pump of the present invention. Figure 2 This is a schematic diagram of the device structure and operating principle of the heat pump cycle of the present invention.

[0035] Example 1

[0036] like Figure 1 and 2As shown, a drying device of a rotary coupling compressor heat pump includes: a dehumidifying rotary wheel (100), a four-way reversing valve (300), a heat pump compressor (200), a gas-liquid separator (400), an air supply system (500), a drying system (600), a regeneration system (700), a one-way valve (800), a liquid storage tank (900), an evaporator (1000), an electronic expansion valve (1100), a solenoid valve (1200), a heat pump channel (1300), and a defrosting auxiliary channel (1400). One end of the dehumidifying rotary wheel (100) is connected to the evaporator (1000), and the other end of the four-way reversing valve (300) is connected to the heat pump compressor (200), the gas-liquid separator (400), and the air supply system (500), the drying system (600), the regeneration system (700), the one-way valve (800), the liquid storage tank (900), the evaporator (1000), the electronic expansion valve (1100), the solenoid valve (1200), the heat pump channel (1300), and the defrosting auxiliary channel (1400). The heat pump compressor (200) is connected to the gas-liquid separator (400). The drying system (600) is connected to the one-way valve (800) through the defrosting auxiliary channel (1400). The drying system (600) is connected to the solenoid valve (1200) and the one-way valve (800) through the heat pump channel (1300). The regeneration system (700) is connected to the one-way valve (800). The regeneration system (700) is connected to the liquid storage tank (900) through the defrosting auxiliary channel (1400). The liquid storage tank (900) is connected to the evaporator (1000). The electronic expansion valve (1100) is located between the liquid storage tank (900) and the evaporator (1000).

[0037] The dehumidification impeller (100) includes a regeneration air duct (110) and a drying air duct (120). The air inlet of the drying air duct (120) is connected to the air-side air duct of the evaporator (1000), the air outlet of the drying air duct (120) is connected to the regeneration system (700), and the air inlet of the regeneration air duct (110) is connected to the drying system (600).

[0038] The drying system (600) includes a first condenser (610) and a first electric heater (620). The first condenser (610) and the first electric heater (620) are respectively connected to the air inlet of the regeneration air duct (110). The first port of the refrigerant side of the first condenser (610) is connected to the second port of the four-way reversing valve (300). The second port of the refrigerant side of the first condenser (610) is connected to the solenoid valve (1200), the one-way valve (800) and the regeneration system (700) through the heat pump channel (1300).

[0039] The regeneration system (700) includes: a second condenser (710) and a second electric heater (720). The second condenser (710) and the second electric heater (720) are respectively connected to the air outlet of the drying air duct (120). The first port of the refrigerant side of the second condenser (710) is connected to the second port of the refrigerant side of the first condenser (610) via a heat pump channel (1300). The second port of the refrigerant side of the second condenser (710) is connected to the first port of the liquid storage tank (900). The second port of the refrigerant side of the second condenser (710) is connected to the second port of the refrigerant side of the first condenser (610) via a defrosting auxiliary channel (1400) and a one-way valve (800).

[0040] The one-way valve (800) includes: a first one-way valve (810) and a second one-way valve (820), wherein the first one-way valve (810) is connected to the second port on the refrigerant side of the first condenser (610), and the second one-way valve (820) is connected to the second port on the refrigerant side of the second condenser (710) and the second port on the refrigerant side of the first condenser (610).

[0041] The air supply system (500) includes a drying air supply fan (510) and a regeneration air supply fan (520), wherein the drying air supply fan (510) is located in the air duct between the second condenser (710) and the second electric heater (720), and the regeneration air supply fan (520) is located in the air duct between the first condenser (610) and the first electric heater (620).

[0042] A method for operating a drying device using a rotary coupling compression heat pump includes the following steps:

[0043] Step 1: Ambient air enters from the air inlet of the drying duct (120), and is pre-cooled to the dew point temperature by the action of the evaporator (1000) driven by the drying blower (510) and sent into the dehumidification wheel (100) for adsorption and dehumidification. The dried air is heated by the action of the second condenser (710) and sent into the drying room.

[0044] Step 2: The ambient air required for regeneration enters from the air inlet of the regeneration air duct (110) and is heated by the regeneration blower (520) under the action of the first condenser (610) for the regeneration of the dehumidification rotor (100).

[0045] Step 3: The second electric heater (720) is used for supplementing the heat and temperature regulation control of the drying air, and the first electric heater (620) is used for supplementing the heat and temperature regulation control of the regenerated air.

[0046] Step 4: By switching the four-way reversing valve (300) and the solenoid valve (1200) on and off, the drying device is controlled to switch between normal drying mode and automatic defrosting mode.

[0047] Step 1 achieves normal mode operation by switching between a four-way reversing valve (300) and a solenoid valve (1200), including the following steps: the heat pump circulating working fluid, driven by the heat pump compressor (200), passes sequentially through the four-way reversing valve (300), the first condenser (610), the solenoid valve (1200), the first check valve (810), the second condenser (710), the liquid storage tank (900), the electronic expansion valve (1100), the evaporator (1000), the four-way reversing valve (300), the gas-liquid separator (400), and finally returns to the suction port of the heat pump compressor (200).

[0048] Step 2 achieves automated defrosting operation mode by switching through a four-way reversing valve (300), including the following steps: the heat pump circulating working fluid, driven by the heat pump compressor (200), passes through the four-way reversing valve (300), evaporator (1000), electronic expansion valve (1100), liquid storage tank (900), second one-way valve (820), first condenser (610), four-way reversing valve (300), gas-liquid separator (400) in sequence and finally returns to the suction port of the heat pump compressor (200).

[0049] The principle of this invention: During use, ambient air enters from the air inlet of the drying duct 120, is pre-cooled to the dew point temperature by the drying blower 510 under the action of the evaporator 1000 and sent into the dehumidification wheel 100 for adsorption and dehumidification. The dried air is heated by the second condenser 710 and sent into the drying room.

[0050] The ambient air required for regeneration enters from the air inlet of the regeneration duct 110 and is heated by the first condenser 610 under the drive of the regeneration blower 520 for the regeneration of the dehumidification rotor 100.

[0051] The second electric heater 720 is located at the rear end of the second condenser 710 and at the front end of the inlet of the adsorption zone of the dehumidification rotor 100. When the drying air temperature of the second condenser 710 is insufficient, the heating power of the second electric heater 720 can be controlled to ensure a stable output temperature of the finished product drying air.

[0052] The first electric heater 620 is located at the rear end of the first condenser 610 and at the front end of the inlet of the regeneration zone of the dehumidifying rotor 100. To ensure the regeneration effect of the dehumidifying rotor 100, when the temperature of the regeneration air in the first condenser 610 is insufficient, the heating power of the first electric heater 620 can be controlled to ensure that the temperature of the regeneration air reaches the conditions required for the regeneration of the dehumidifying rotor 100.

[0053] In the heat pump cycle, the four-way reversing valve 300 and the solenoid valve 1200 can be switched to achieve normal operation. Driven by the heat pump compressor 200, the heat pump working fluid sequentially passes through the four-way reversing valve 300, the first condenser 610, the solenoid valve 1200, the first check valve 810, the second condenser 710, the liquid receiver 900, the electronic expansion valve 1100, the evaporator 1000, the four-way reversing valve 300, the gas-liquid separator 400, and finally returns to the suction port of the heat pump compressor 200, completing the cycle. At this time, the evaporator 1000 has an evaporation temperature lower than the ambient air dew point temperature, absorbs heat from the outside, and pre-cools and pre-dehumidifies the ambient air entering the adsorption zone of the dehumidifying rotor 100; the first condenser 610 releases heat to the outside, and its condensation heat is recovered for the preheating of regenerated air at the inlet of the regeneration zone of the dehumidifying rotor 100; the second condenser 710 releases heat to the outside, and its condensation heat is recovered for the heating of dry air at the outlet of the adsorption zone of the dehumidifying rotor 100.

[0054] In the heat pump cycle, the four-way reversing valve 300 can switch to achieve an automated defrosting operation mode. Driven by the heat pump compressor 200, the heat pump working fluid sequentially passes through the four-way reversing valve 300, evaporator 1000, electronic expansion valve 1100, liquid receiver 900, second one-way valve 820, first condenser 610, four-way reversing valve 300 again, gas-liquid separator 400, and finally returns to the suction port of the heat pump compressor 200, completing the cycle. At this time, the evaporator 1000 releases heat to defrost, the first condenser 610 absorbs heat, and the second condenser 710 is bypassed and inactive under the action of the solenoid valve 1200 and the second one-way valve 820. After defrosting is complete, the heat pump cycle control system switches the four-way reversing valve 300 and solenoid valve 1200 back to normal operation.

[0055] In summary, the innovation of this invention lies in the following: This invention discloses a drying device and its operation method of a rotary coupling compression heat pump, which utilizes the heat pump evaporator to precool the air processed on the adsorption side of the dehumidifying rotary wheel, utilizes the first condenser of the heat pump to preheat the air on the regeneration side, and utilizes the second condenser of the heat pump to heat the drying air supply. This improves the drying effect of the drying device while reducing system energy consumption.

[0056] The present invention provides a drying device and its operation method of a rotary coupling compression heat pump. Through the dehumidification and drying effect of the dehumidification rotary wheel, the condensation heating of the second condenser, and the heating and temperature regulation effect of the second electric heater, high temperature and low humidity drying air is generated, which can reduce the air volume and ensure the drying effect at low wind speed.

[0057] The present invention provides a drying device and its operation method for a rotary coupling compression heat pump. By recovering the waste heat from the first condenser and supplementing it with the heating effect of the first electric heater, high-temperature regenerated air is formed, ensuring the regeneration effect of the dehumidifying rotor.

[0058] The present invention provides a drying device and its operation method for a rotary coupling compression heat pump, which can adjust the cooling capacity and pre-cooling effect of the evaporator by means of an electronic expansion valve according to the changes in the air being processed by the environment, thereby ensuring the efficient and stable operation of the heat pump cycle.

[0059] The present invention provides a drying device and its operation method for a rotary coupling compression heat pump. By switching between a four-way reversing valve and a solenoid valve, the normal operation mode and the automatic defrosting mode of the heat pump cycle can be realized, ensuring the normal and stable operation of the system.

[0060] The core technical feature of this invention is that it satisfies the requirements of two series recovery systems. The operating conditions of the refrigeration system cannot meet the requirements of all-weather operation according to conventional design. Under this premise, the difficulty and core of this invention is that the two simultaneous series recovery systems must not only ensure recovery under two different operating conditions, but also ensure that the refrigeration system can operate normally.

[0061] The regenerative blower 520 powers the regenerated air from the dehumidifying impeller 100 and employs variable frequency control. Condensers are connected in series to ensure operation under various conditions. By adjusting the frequency of the regenerative blower 520 and thus the regenerated airflow, the refrigeration system is ensured to operate normally under different conditions.

[0062] The first one-way valve 810 is a refrigerant bypass for the second condenser 710. By adjusting the flow ratio between the bypass and the second condenser 710, the supply air temperature can be adjusted, and the condensing pressure of the refrigeration system can be adjusted to ensure that the refrigeration system adapts to different operating conditions.

[0063] Other auxiliary features include a gas injection and enthalpy adjustment device to address the low enthalpy and excess cooling capacity of the environment during transitional seasons. This invention can also be configured with an additional dual-external-venting condenser to handle extreme high-temperature conditions. Under extreme high-temperature conditions, this external venting condenser cooling channel will be activated to ensure the stability of the refrigeration system.

[0064] The specific embodiments of the present invention have been described above, but the present invention is not limited thereto. Various changes can be made to the present invention as long as they do not depart from the spirit of the present invention.

Claims

1. A drying device for a rotary coupling compression heat pump, characterized in that, include: The system includes a dehumidifying impeller (100), a four-way reversing valve (300), a heat pump compressor (200), a gas-liquid separator (400), an air supply system (500), a drying system (600), a regeneration system (700), a one-way valve (800), a liquid storage tank (900), an evaporator (1000), an electronic expansion valve (1100), a solenoid valve (1200), a heat pump channel (1300), and a defrosting auxiliary channel (1400). One end of the dehumidifying impeller (100) is connected to the evaporator (1000), and the other end of the four-way reversing valve (300) is connected to the heat pump compressor (200), the gas-liquid separator (400), and the drying system (600). The heat pump compressor (200) is connected to the gas-liquid separator (400), the drying system (600) is connected to the one-way valve (800) through the defrosting auxiliary channel (1400), the drying system (600) is connected to the solenoid valve (1200) and the one-way valve (800) through the heat pump channel (1300), the regeneration system (700) is connected to the one-way valve (800), the regeneration system (700) is connected to the liquid storage tank (900) through the defrosting auxiliary channel (1400), the liquid storage tank (900) is connected to the evaporator (1000), and the electronic expansion valve (1100) is located between the liquid storage tank (900) and the evaporator (1000). The dehumidification impeller (100) includes a regeneration air duct (110) and a drying air duct (120). The air inlet of the drying air duct (120) is connected to the air-side air duct of the evaporator (1000), the air outlet of the drying air duct (120) is connected to the regeneration system (700), and the air inlet of the regeneration air duct (110) is connected to the drying system (600). The drying system (600) includes: a first condenser (610) and a first electric heater (620). The first condenser (610) and the first electric heater (620) are respectively connected to the air inlet of the regeneration air duct (110). The first port of the refrigerant side of the first condenser (610) is connected to the second port of the four-way reversing valve (300). The second port of the refrigerant side of the first condenser (610) is connected to the solenoid valve (1200), the one-way valve (800) and the regeneration system (700) through the heat pump channel (1300). The regeneration system (700) includes: a second condenser (710) and a second electric heater (720). The second condenser (710) and the second electric heater (720) are respectively connected to the air outlet of the drying air duct (120). The first port of the refrigerant side of the second condenser (710) is connected to the second port of the refrigerant side of the first condenser (610) via a heat pump channel (1300). The second port of the refrigerant side of the second condenser (710) is connected to the first port of the liquid storage tank (900). The second port of the refrigerant side of the second condenser (710) is connected to the second port of the refrigerant side of the first condenser (610) via a defrosting auxiliary channel (1400) and a one-way valve (800). The one-way valve (800) includes: a first one-way valve (810) and a second one-way valve (820), wherein the first one-way valve (810) is connected to the second port on the refrigerant side of the first condenser (610), and the second one-way valve (820) is connected to the second port on the refrigerant side of the second condenser (710) and the second port on the refrigerant side of the first condenser (610).

2. The drying device of a rotary coupling compression heat pump according to claim 1, characterized in that: The air supply system (500) includes a drying air supply fan (510) and a regeneration air supply fan (520), wherein the drying air supply fan (510) is located in the air duct between the second condenser (710) and the second electric heater (720), and the regeneration air supply fan (520) is located in the air duct between the first condenser (610) and the first electric heater (620).

3. The operating method of the drying device of the rotary coupling compression heat pump according to claim 1, characterized in that, Includes the following steps: Step 1: Ambient air enters from the air inlet of the drying duct (120), and is pre-cooled to the dew point temperature by the action of the evaporator (1000) driven by the drying blower (510) and sent into the dehumidification wheel (100) for adsorption and dehumidification. The dried air is heated by the action of the second condenser (710) and sent into the drying room. Step 2: The ambient air required for regeneration enters from the air inlet of the regeneration air duct (110) and is heated by the regeneration blower (520) under the action of the first condenser (610) for the regeneration of the dehumidification rotor (100). Step 3: The second electric heater (720) is used for supplementing the heat and temperature regulation control of the drying air, and the first electric heater (620) is used for supplementing the heat and temperature regulation control of the regenerated air; Step 4: By switching the four-way reversing valve (300) and the solenoid valve (1200) on and off, the drying device is controlled to switch between normal drying mode and automatic defrosting mode.

4. The operating method of the drying device of the rotary coupling compression heat pump according to claim 3, characterized in that: Step 1 achieves normal mode operation by switching between a four-way reversing valve (300) and a solenoid valve (1200), including the following steps: the heat pump circulating working fluid, driven by the heat pump compressor (200), passes sequentially through the four-way reversing valve (300), the first condenser (610), the solenoid valve (1200), the first check valve (810), the second condenser (710), the liquid storage tank (900), the electronic expansion valve (1100), the evaporator (1000), the four-way reversing valve (300), the gas-liquid separator (400), and finally returns to the suction port of the heat pump compressor (200).

5. The operating method of the drying device of the rotary coupling compression heat pump according to claim 3, characterized in that: Step 2 achieves automated defrosting operation mode by switching through a four-way reversing valve (300), including the following steps: the heat pump circulating working fluid, driven by the heat pump compressor (200), passes through the four-way reversing valve (300), evaporator (1000), electronic expansion valve (1100), liquid storage tank (900), second one-way valve (820), first condenser (610), four-way reversing valve (300), gas-liquid separator (400) in sequence and finally returns to the suction port of the heat pump compressor (200).

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