A quaternary heat recovery type air conditioning unit and working method

Abstract

The application relates to the technical field of dehumidification air conditioning units, and particularly discloses a four-element heat recovery type air conditioning unit and a working method, wherein the heat recovery air conditioning unit comprises an air conditioner filter, a front heat recovery heat exchanger, a main heat exchanger, a rear heat recovery heat exchanger, a reheating heat exchanger and a supply fan; the heat recovery exhaust fan unit comprises an exhaust filter, an exhaust heat recovery heat exchanger and an exhaust fan; and the heat pump device comprises a compressor, a three-way valve and a four-way reversing valve. The heat pump system is arranged between the air conditioning unit and the exhaust fan unit, the cold of the exhaust air is recovered in summer, the air inlet of the air conditioning unit is pre-cooled, deep dehumidification and reheating are realized, the evaporation temperature of the rear heat recovery heat exchanger of the heat pump is low, the deep dehumidification can be realized, the cold source temperature of the main heat exchanger can be raised, the energy efficiency of the cold source is improved, the heat of the exhaust air can be recovered in winter, the air inlet of the air conditioning unit is preheated and reheated, the supply air temperature can be stabilized through reheating, constant temperature and humidity are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dehumidification air conditioning unit, in particular to a four-element heat recovery type air conditioning unit and working method. BACKGROUND

[0002] Heat recovery units are mostly used for heat recovery between new exhaust air and exhaust air in industrial and civil buildings. Heat recovery units are widely used in most areas. Especially in hospitals, office buildings, libraries, hotels, laboratories, public transportation buildings, production plants and other environments with a large amount of exhaust air and a large temperature difference or enthalpy difference between new exhaust air.

[0003] Common heat recovery forms include plate heat recovery, rotary heat recovery, solution heat recovery, heat pipe heat recovery and several other forms. However, the above devices can only recover heat through heat transfer when recovering heat, and the recovered energy is subject to the enthalpy difference between the recovered air and the air to be recovered. The heat recovery system constructed by the heat pump can achieve higher heat recovery through the phase change of the refrigerant. Even if the enthalpy difference between the recovered air and the air to be recovered is very small, because the refrigerant used for energy transfer changes phase, there is a larger temperature difference between the refrigerant and the air, and through the switching of the pipeline and the adjustment of the expansion valve, not only can the energy of the exhaust air be recovered, but also the low-temperature refrigerant can achieve deep dehumidification of the air, and the high-temperature refrigerant can be used for air reheating, meeting the temperature and humidity control requirements of the air handling unit, achieving three goals at once.

[0004] Therefore, it is urgent to design a four-element heat recovery type air conditioning unit and working method to solve the problem that the current air conditioning unit is subject to a large temperature difference or a large enthalpy difference. SUMMARY

[0005] In view of the problems in the prior art, the purpose of the present application is to provide a four-element heat recovery type air conditioning unit and working method, which sets a heat pump device between the air conditioning unit and the exhaust air handling unit to recover the cold energy of the exhaust air in summer cooling conditions, pre-cool the air inlet of the air conditioning unit, and also dehumidify and reheat the air. Recover the heat of the exhaust air in summer heating conditions, pre-heat the air inlet of the air conditioning unit, prevent freezing of the unit, and also reheat the humidified air, achieving four goals at once. The heat recovery efficiency is as high as 75% or more.

[0006] The technical scheme adopted by the present application to solve its technical problems is: a four-element heat recovery type air conditioning unit, comprising a heat recovery air conditioning unit, a heat recovery exhaust air handling unit and a heat pump device, the heat recovery air conditioning unit comprising an air conditioning filter, a front heat recovery heat exchanger, a main heat exchanger, a rear heat recovery heat exchanger, a reheating heat exchanger and a supply fan, the heat recovery exhaust air handling unit comprising an exhaust air filter, an exhaust air heat recovery heat exchanger and an exhaust fan, and the heat pump device comprising a compressor, a three-way valve and a four-way reversing valve.

[0007] The exhaust port of the compressor is connected with the inlet of the three-way valve, one outlet of the three-way valve is connected with the inlet of the reheating heat exchanger, the other outlet of the three-way valve is connected with the outlet of the reheating heat exchanger in parallel and then connected with the inlet of the four-way reversing valve, and a one-way valve one is arranged on the outlet of the reheating heat exchanger.

[0008] Specifically, the outlet of the exhaust heat recovery heat exchanger is divided into two paths, one path of the outlet of the exhaust heat recovery heat exchanger is connected with the inlet of the post heat recovery heat exchanger through the heating electronic expansion valve and the main electronic expansion valve, and the other path of the outlet of the exhaust heat recovery heat exchanger is connected with the inlet of the pre heat recovery heat exchanger through the auxiliary electronic expansion valve.

[0009] Specifically, the heating electronic expansion valve is connected with four one-way valves in parallel, and the auxiliary electronic expansion valve is connected with three one-way valves in parallel.

[0010] Specifically, the heat pump device is provided with four sets of pipelines, and the four sets of pipelines are respectively connected with the pre heat recovery heat exchanger, the post heat recovery heat exchanger, the reheating heat exchanger and the exhaust heat recovery heat exchanger in the heat recovery air conditioning unit.

[0011] Specifically, the main heat exchanger is connected with an external cold and heat source device through a pipeline, and the external cold and heat source device adopts one of a wind-cooled heat pump, a cold water host, a wind-cooled direct expansion machine and a water-cooled direct expansion machine.

[0012] Specifically, the pre heat recovery heat exchanger, the main heat exchanger, the post heat recovery heat exchanger, the reheating heat exchanger and the exhaust heat recovery heat exchanger are all finned heat exchangers.

[0013] Specifically, an air conditioner filter is installed at the air inlet of the heat recovery air conditioning unit, a supply fan is installed at the air outlet of the heat recovery air conditioning unit, an exhaust filter is installed at the return air inlet of the heat recovery exhaust fan unit, and an exhaust fan is installed at the exhaust air outlet of the heat recovery exhaust fan unit.

[0014] Specifically, the supply fan and the exhaust fan both adopt one of an alternating current motor and a direct current brushless EC motor.

[0015] Specifically, the air inlet of the heat recovery air conditioning unit takes outdoor fresh air or indoor return air or mixed air of fresh air and return air.

[0016] A working method of a four-element heat recovery type air conditioning unit, comprising the following steps:

[0017] S1, when the heat recovery air conditioning unit is refrigerating, the heat pump device operates according to the refrigeration condition, the front heat recovery heat exchanger and the rear heat recovery heat exchanger become evaporators, the reheating heat exchanger becomes a primary condenser, and the exhaust air heat recovery heat exchanger becomes a secondary condenser;

[0018] S2, air is purified through the air conditioner filter first, then pre-cooled through the front heat recovery heat exchanger, secondary cooled and dehumidified through the main heat exchanger, deeply dehumidified through the rear heat recovery heat exchanger, and reheated through the reheating heat exchanger, wherein whether the reheating heat exchanger is heated is realized by controlling the flow direction of freon through the three-way valve of the heat pump device, and the compressor condensing heat that is not used by the reheating heat exchanger is dissipated into the exhaust fan through the exhaust air heat recovery heat exchanger and discharged to the outdoor;

[0019] S3, when the heat recovery air conditioning unit is heating, the heat pump device operates according to the heating condition, the reheating heat exchanger is still a primary condenser, the front heat recovery heat exchanger becomes a secondary condenser, the rear heat recovery heat exchanger does not work, the refrigerant is cut off by the four one-way valves and three electronic expansion valves, and the exhaust air heat recovery heat exchanger becomes an evaporator;

[0020] S4, air is purified through the air conditioner filter first, then pre-heated through the front heat recovery heat exchanger, secondary heated through the main heat exchanger, and reheated through the reheating heat exchanger, wherein whether the reheating heat exchanger is heated is realized by controlling the flow direction of freon through the three-way valve of the heat pump device.

[0021] The application has the following beneficial effects:

[0022] The four-element heat recovery type air conditioning unit and the working method are characterized in that a heat pump system is arranged between the air conditioning unit and the exhaust fan, the heat of the exhaust air is recovered in summer to pre-cool, deeply dehumidify and reheat the air entering the air conditioning unit, the evaporation temperature of the rear heat recovery heat exchanger of the heat pump is low and can meet the requirement of deep dehumidification, so the cold source temperature of the main heat exchanger is raised to improve the energy efficiency of the cold source, the condensing heat of the heat pump is used to reheat the dehumidified air for free to achieve constant temperature and humidity, the heat of the exhaust air is recovered in winter to pre-heat and reheat the air entering the air conditioning unit, especially in the system using isenthalpic humidification, the temperature after the humidifier is low, the temperature of the supply air can be stabilized through reheating to achieve constant temperature and humidity, and the heat recovery efficiency is as high as 75% or more. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of the four-element heat recovery type air conditioning unit.

[0024] In the diagram: 1. Heat recovery air conditioning unit housing; 2. Heat recovery exhaust fan unit housing; 3. Heat pump unit; 4. External cold and heat source unit; 1-1. Air conditioning filter; 1-2. Pre-heat recovery heat exchanger; 1-3. Main heat exchanger; 1-4. Post-heat recovery heat exchanger; 1-5. Reheat heat exchanger; 1-6. Supply fan; 2-1. Exhaust air filter; 2-2. Exhaust air heat recovery heat exchanger; 2-3. Exhaust fan; 3-1. Compressor; 3-2. Three-way valve; 3-3. Check valve one; 3-4. Four-way reversing valve; 3-5. Main electronic expansion valve; 3-6. Auxiliary electronic expansion valve; 3-7. Check valve two; 3-8. Check valve three; 3-9. Check valve four; 3-10. Heating electronic expansion valve. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, a quaternary heat recovery type air conditioning unit includes a heat recovery air conditioning unit 1, a heat recovery exhaust fan unit 2, a heat pump device 3, and heat recovery pipes.

[0027] It should be noted that the heat recovery exhaust fan unit 2 includes: exhaust filter 2-1, exhaust heat recovery heat exchanger 2-2, and exhaust fan 2-3.

[0028] It should be noted that the heat recovery air conditioning unit 1 includes: air conditioning filter 1-1, pre-heat recovery heat exchanger 1-2, main heat exchanger 1-3, post-heat recovery heat exchanger 1-4, reheat heat exchanger 1-5, and blower 1-6.

[0029] It should be noted that the heat pump unit 3 includes: compressor 3-1, three-way valve 3-2, four-way reversing valve 3-4, one-way valve 1 3-3, one-way valve 2 3-7, one-way valve 3-8 and one-way valve 4 3-9, main electronic expansion valve 3-5, auxiliary electronic expansion valve 3-6, heating expansion valve 3-10 and piping.

[0030] It should be noted that the heat pump unit 3 has four sets of pipelines (one inlet and one outlet constitute one set). Among them, e-1 and e-2 are connected to the inlet and outlet of the pre-heat recovery heat exchanger 1-2 in the heat recovery air conditioning unit, respectively; d-1 and d-2 are connected to the inlet and outlet of the post-heat recovery heat exchanger 1-4, respectively; c-1 and c-2 are connected to the inlet and outlet of the reheat heat exchanger 1-5, respectively; and o-1 and o-2 are connected to the inlet and outlet of the exhaust heat recovery heat exchanger 2-2 in the heat recovery exhaust fan unit, respectively.

[0031] The outlet of the compressor 3-1 is connected with the inlet of the three-way valve 3-2, the outlet a of the three-way valve 3-2 is connected with the inlet c-1 of the reheating heat exchanger 1-5, the outlet c-2 of the reheating heat exchanger 1-5 is connected with the inlet f-1 of the one-way valve 3-3, the outlet b of the three-way valve 3-2 is connected with the outlet f-2 of the one-way valve 3-3, and then connected with the inlet i of the four-way valve 3-4 in parallel; the outlet m of the four-way valve 3-4 is connected with the inlet o-1 of the exhaust heat recovery heat exchanger 2-2, the outlet j is connected with the outlet e-2 of the preheat recovery heat exchanger 1-2 and the outlet g-2 of the one-way valve 3-7 in parallel, the outlet d-2 of the postheat recovery heat exchanger 1-4 is connected with the inlet g-1 of the one-way valve 3-7; the outlet k of the four-way valve 3-4 is connected with the suction port of the compressor 3-1; the outlet o-2 of the exhaust heat recovery heat exchanger 2-2 is divided into two paths, the outlet o-2 is connected with the one-way valve 3-9 and the heating expansion valve 3-10 in parallel, one path of the outlet of the exhaust heat recovery heat exchanger 2-2 is connected with the h-2 port of the main electronic expansion valve 3-5, and the other path is connected with the p-2 port of the auxiliary electronic expansion valve 3-6, the h-1 port of the main electronic expansion valve 3-5 is connected with the inlet d-1 of the postheat recovery heat exchanger 1-4, and the p-1 port of the auxiliary electronic expansion valve 3-6 is connected with the inlet e-1 of the preheat recovery heat exchanger, the heating electronic expansion valve 3-10 is connected with the one-way valve 4 3-9 in parallel, and the auxiliary electronic expansion valve 3-6 is connected with the one-way valve 3 3-8 in parallel.

[0032] It should be noted that when the heat recovery air conditioning unit 1 is cooling, the heat pump device 3 operates according to the cooling condition, the front heat recovery heat exchanger 1-2 and the rear heat recovery heat exchanger 1-4 become evaporators, the reheating heat exchanger 1-5 becomes a primary condenser, and the exhaust air heat recovery heat exchanger 2-2 becomes a secondary condenser. The air first passes through the filter 1-1 for purification, then passes through the front heat recovery heat exchanger 1-2 for pre-cooling, the main heat exchanger 1-3 for secondary cooling and dehumidification, then passes through the rear heat recovery heat exchanger 1-4 for deep dehumidification, and finally passes through the reheating heat exchanger 1-5 for reheating. The refrigerant flow direction of the heat pump device 3 is that the high-temperature and high-pressure refrigerant discharged from the compressor 3-1 flows into the reheating heat exchanger 1-5 through the three-way valve 3-2. When the condensation heat is needed for reheating, the a port of the three-way valve 3-2 is opened and the b port is closed, the high-temperature and high-pressure refrigerant flows into the reheating heat exchanger 1-5, and the air flowing through the reheating heat exchanger 1-5 is reheated. When reheating is not needed, the b port of the three-way valve 3-2 is opened and the a port is closed, the high-temperature and high-pressure refrigerant flow is blocked by the one-way valve 3-3 and cannot enter the reheating heat exchanger 1-5. The high-temperature refrigerant flowing out of the reheating heat exchanger 1-5 or the high-temperature refrigerant directly flowing out of the b port of the three-way valve 3-2 flows into the exhaust air heat recovery heat exchanger 2-2 through the i port of the four-way reversing valve 3-4 and then flows out through the m port and enters the exhaust air heat recovery heat exchanger 2-2 through the o-1 port. The high-temperature and high-pressure refrigerant entering the heat recovery heat exchanger 2-2 exchanges heat with the exhaust air and dissipates heat into the exhaust air, becoming a high-pressure liquid, and then flows out through the o-2 port. The liquid refrigerant flowing out through the o-2 port flows out through the one-way valve four 3-9, at this time the heating expansion valve 3-10 is closed, and after the one-way valve four 3-9, it is divided into two ways, one way through the auxiliary electronic expansion valve 3-6 after throttling enters the front heat recovery heat exchanger 1-2, and the other way through the main electronic expansion valve 3-5 after throttling enters the rear heat recovery heat exchanger 1-4. The liquid refrigerant evaporated in the evaporator becomes a gaseous state and is combined into the j port of the four-way reversing valve 3-4 through the d-2 and e-2 ports, and then returns to the compressor 3-1 through the k port, completing the cycle.

[0033] It should be noted that when the heat recovery air conditioning unit 2 is in heating mode, the heat pump unit 3 operates according to the heating condition. The reheat heat exchanger 1-5 remains a primary condenser, the pre-heat recovery heat exchanger 1-2 becomes a secondary condenser, the post-heat recovery heat exchanger 1-4 is not working (the refrigerant inflow is cut off by the one-way valve 3-3 and the main electronic expansion valve 3-5), and the exhaust heat recovery heat exchanger 2-2 becomes an evaporator. The refrigerant flow of the heat pump unit 3 is from the high-temperature, high-pressure refrigerant discharged from the compressor 3-1 through the three-way valve 3-2. When reheating using condensation heat is required, port a of the three-way valve 3-2 is open and port b is closed, allowing the high-temperature, high-pressure refrigerant to flow into the reheat heat exchanger 1-5, which can reheat the air flowing through it. When reheating is not required, port b of the three-way valve 3-2 is open and port a is closed, preventing the high-temperature, high-pressure refrigerant from entering the reheat heat exchanger 1-5 due to the one-way valve 3-3. The high-temperature refrigerant flowing from the reheat heat exchanger 1-5 or directly from port b of the three-way valve 3-2 flows into the four-way reversing valve 3-4 through port i, then out through port j and enters the pre-heat recovery heat exchanger 1-2 through port e-2. The high-temperature, high-pressure refrigerant in the pre-heat recovery heat exchanger 1-2 exchanges heat with the air inside the heat recovery air conditioning unit 1, dissipating the heat into the air and becoming a high-pressure liquid, which then flows out through port e-1. The liquid refrigerant flowing out through port e-1 flows out through check valve 3-8. At this time, the auxiliary electronic expansion valve 3-6 is closed, and the refrigerant from check valve 3-8 passes through the heating electronic expansion valve 3-10 and enters the exhaust heat recovery heat exchanger 2-2. The liquid refrigerant, after evaporating in the evaporator, becomes a gas and enters the four-way reversing valve 3-4 through port o-1, then returns to the compressor 3-1 through port k, completing the cycle. When heating, the main electronic expansion valve 3-5 is closed, and the high-temperature and high-pressure refrigerant flow is blocked by the one-way valve 2 3-7 and cannot enter the post-heat recovery heat exchanger 1-4, so the post-heat recovery heat exchanger does not work.

[0034] In this embodiment, the main heat exchangers 1-3 of the heat recovery air conditioning unit 1 and the external cold and heat source device 4 are one of the following: air-cooled heat pump, chiller, air-cooled direct expansion machine, and water-cooled direct expansion machine.

[0035] In this embodiment, the preheating heat exchanger 1-2, main heat exchanger 1-3, postheating heat exchanger 1-4, and reheat heat exchanger 1-5 in the heat recovery air conditioning unit 1 are finned heat exchangers.

[0036] In this embodiment, the exhaust fan 2-3 in the heat recovery exhaust fan unit 2 is either an AC motor or a DC brushless EC motor.

[0037] In this embodiment, the blowers 1-6 in the heat recovery air conditioning unit 1 are either AC motors or DC brushless EC motors.

[0038] In the embodiment, the air conditioner unit of the heat recovery air conditioner unit 1 takes outdoor fresh air or indoor return air or mixed air of fresh air and return air.

[0039] In the embodiment, the heat recovery air conditioner unit 1 is provided with primary, medium and high efficiency filters or purifiers (forms are not limited) according to requirements, and can be provided with humidifiers (types are not limited) and other functional components.

[0040] In the embodiment, the system of the heat pump device 3 can be provided with filters, oil separators, liquid storage tanks, gas-liquid separators and other refrigeration components according to requirements.

[0041] The present application is not limited to the above-mentioned embodiments, and any person should know that the structural changes made under the inspiration of the present application, any technical solution with the same or similar to the present application, falls within the scope of the present application.

[0042] The technical, shape, structure parts not described in detail in the present application are all known technologies.

Claims

1. A quaternary heat recovery type air conditioning unit, characterized in that, It includes a heat recovery air conditioning unit, a heat recovery exhaust fan unit, and a heat pump device. The heat recovery air conditioning unit includes an air conditioning filter, a pre-heat recovery heat exchanger, a main heat exchanger, a post-heat recovery heat exchanger, a reheat heat exchanger, and a blower. The heat recovery exhaust fan unit includes an exhaust filter, an exhaust heat recovery heat exchanger, and an exhaust fan. The heat pump device includes a compressor, a three-way valve, and a four-way reversing valve. An air conditioning filter is installed at the air inlet of the heat recovery air conditioning unit, a blower is installed at the air outlet of the heat recovery air conditioning unit, an exhaust filter is installed at the return air outlet of the heat recovery exhaust fan unit, and an exhaust fan is installed at the exhaust outlet of the heat recovery exhaust fan unit. The compressor's discharge port is connected to the inlet of a three-way valve. One outlet of the three-way valve is connected to the inlet of the reheat heat exchanger. The other outlet of the three-way valve is connected in parallel with the outlet of the reheat heat exchanger and then connected to the inlet of a four-way reversing valve. A check valve is installed on the outlet of the reheat heat exchanger. One reversing outlet of the four-way reversing valve is connected to the inlet of the exhaust heat recovery heat exchanger. The other reversing outlet of the four-way reversing valve is connected to a pipeline that connects the outlets of the pre-heat recovery heat exchanger and the post-heat recovery heat exchanger in parallel. A check valve is installed on the outlet pipeline of the post-heat recovery heat exchanger. The outlet of the four-way reversing valve is connected to the compressor's suction port. The outlet of the exhaust heat recovery heat exchanger is split into two paths. One path of the exhaust heat recovery heat exchanger outlet is connected to the inlet of the post-heat recovery heat exchanger through the heating electronic expansion valve and the main electronic expansion valve. The other path of the exhaust heat recovery heat exchanger outlet is connected to the inlet of the pre-heat recovery heat exchanger through the auxiliary electronic expansion valve. The heating electronic expansion valve is connected in parallel with check valve four, and the auxiliary electronic expansion valve is connected in parallel with check valve three.

2. The quaternary heat recovery air conditioning unit according to claim 1, characterized in that, The heat pump device is equipped with four sets of pipelines, which are respectively connected to the pre-heat recovery heat exchanger, post-heat recovery heat exchanger, reheat heat exchanger in the heat recovery air conditioning unit, and the exhaust heat recovery heat exchanger in the heat recovery exhaust fan unit.

3. The quaternary heat recovery type air conditioning unit according to claim 1, characterized in that, The main heat exchanger is connected to an external heat source device via pipelines. The external heat source device can be one of the following: an air-cooled heat pump, a chiller, an air-cooled direct expansion machine, or a water-cooled direct expansion machine.

4. The quaternary heat recovery air conditioning unit according to claim 1, characterized in that, The preheating heat recovery heat exchanger, main heat exchanger, postheating heat recovery heat exchanger, reheat heat exchanger, and exhaust heat recovery heat exchanger are all finned heat exchangers.

5. The quaternary heat recovery type air conditioning unit according to claim 1, characterized in that, Both the blower and the exhaust fan are powered by either an AC motor or a DC brushless EC motor.

6. The quaternary heat recovery type air conditioning unit according to claim 1, characterized in that, The air inlet of the heat recovery air conditioning unit takes in outdoor fresh air, indoor return air, or a mixture of fresh and return air.

7. The operating method of the quaternary heat recovery air conditioning unit according to any one of claims 1-6, characterized in that, Includes the following steps: S1. When the heat recovery air conditioning unit is cooling, the heat pump device operates according to the cooling condition. The pre-heat recovery heat exchanger and the post-heat recovery heat exchanger become evaporators, the reheat heat exchanger becomes the first-stage condenser, and the exhaust heat recovery heat exchanger becomes the second-stage condenser. S2. The air is first purified by the air conditioning filter, then pre-cooled by the pre-heat recovery heat exchanger, then cooled and dehumidified by the main heat exchanger, then deeply dehumidified by the post-heat recovery heat exchanger, and then reheated by the reheat heat exchanger. Whether the reheat heat exchanger can generate heat is controlled by the three-way valve of the heat pump unit to control the flow of Freon. The compressor condensation heat that cannot be utilized by the reheat heat exchanger is dissipated to the exhaust fan through the exhaust heat recovery heat exchanger and discharged to the outside. S3. When the heat recovery air conditioning unit is in heating mode, the heat pump device operates according to the heating condition. The reheat heat exchanger is still the first-stage condenser, the pre-heat recovery heat exchanger becomes the second-stage condenser, the post-heat recovery heat exchanger does not work, and the refrigerant is cut off by four one-way valves and three electronic expansion valves. The exhaust heat recovery heat exchanger becomes the evaporator. S4. The air is first purified by the air conditioning filter, then preheated by the preheating heat recovery heat exchanger, then reheated by the main heat exchanger, and then reheated by the reheat heat exchanger. Whether the reheat heat exchanger can heat is controlled by the three-way valve of the heat pump device to control the flow of Freon.

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