Heat pump unit and control method thereof

Abstract

The present application relates to the technical field of heat pump unit, and particularly provides a heat pump unit and a control method thereof, aiming at solving the problems of high power consumption and low heating efficiency of the existing method for preventing the compressor liquid strike phenomenon when the heat pump unit starts. To this end, the heat pump unit comprises a refrigerant circulation loop and a bypass heating loop, the compressor and the condenser are arranged on the refrigerant circulation loop, at least a part of the bypass heating loop is arranged in the condenser, the heating member is arranged on the bypass heating loop, the heating member is arranged near the compressor, and the heating member is arranged to heat the refrigerant in the compressor. Based on the arrangement of the bypass heating loop, the waste heat generated by the condenser when condensing the refrigerant can be effectively utilized to heat the refrigerant in the compressor, so that the refrigerant is prevented from becoming liquid and dissolving in the refrigerant oil, and the time required for the heat pump unit to start again can be shortened, the cost can be effectively reduced, and resource waste can be avoided.

Description

Technical Field

[0001] This invention relates to the field of heat pump unit technology, and specifically provides a heat pump unit and its control method. Background Technology

[0002] Air source heat pump units start and stop according to user needs during operation. When the heat pump unit stops, the temperature drops, the refrigerant liquefies, and the refrigerant in the compressor easily mixes with the refrigeration oil. Furthermore, the refrigeration oil becomes viscous due to the lower temperature, making the refrigerant more likely to remain in the oil and less prone to evaporation. When the heat pump unit restarts, the compressor is prone to internal component damage due to liquid compression, shortening the compressor's lifespan. Current technology typically installs an electric heating belt at the bottom of the compressor to evaporate the refrigerant in the refrigeration oil from a liquid to a gaseous state before the heat pump unit starts, preventing liquid slugging in the compressor. However, the heating efficiency of electric heating belts is low, and there are potential electrical hazards and high electricity costs.

[0003] Accordingly, there is a need in the field for a new heat pump unit and its control method to solve the above-mentioned technical problems. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned technical problems, namely, to solve the problems of high electricity cost and low heating efficiency of existing methods for preventing compressor liquid slugging during the start-up of heat pump units.

[0005] In a first aspect, the present invention provides a heat pump unit, the heat pump unit including a refrigerant circulation loop and a bypass heating loop, wherein a compressor and a condenser are disposed on the refrigerant circulation loop, at least a portion of the bypass heating loop is disposed in the condenser, a heating element is disposed on the bypass heating loop, the heating element is disposed near the compressor, and the heating element is configured to heat the refrigerant in the compressor.

[0006] In the preferred embodiment of the above-mentioned heat pump unit, the heat pump unit further includes an electric heating belt, which is disposed near the compressor.

[0007] In the preferred embodiment of the above-mentioned heat pump unit, an electromagnetic control valve is provided on the bypass heating circuit. The electromagnetic control valve is located at the outlet of the condenser and is configured to control the connection state of the bypass heating circuit.

[0008] In the preferred embodiment of the above-mentioned heat pump unit, the heating component is a shell-and-tube heat exchanger.

[0009] In another aspect, the present invention also provides a control method for a heat pump unit, the heat pump unit including a refrigerant circulation loop and a bypass heating loop, wherein a compressor and a condenser are disposed on the refrigerant circulation loop, at least a portion of the bypass heating loop is disposed in the condenser, a heating element is disposed on the bypass heating loop, the heating element is disposed near the compressor, the heating element is configured to heat the refrigerant in the compressor, and an electric heating belt is also disposed near the compressor. The control method includes: acquiring the outlet water temperature of the condenser; and selectively controlling the connection state of the bypass heating loop and the on / off state of the electric heating belt according to the outlet water temperature.

[0010] In the preferred embodiment of the above control method, the step of "selectively controlling the connection state of the bypass heating circuit and the opening / closing state of the electric heating belt according to the outlet water temperature" includes: when the heat pump unit stops running or is in standby mode, if the outlet water temperature is greater than or equal to a first preset outlet water temperature, then the bypass heating circuit is connected and the electric heating belt is not turned on.

[0011] In the preferred embodiment of the above control method, the step of "selectively controlling the connection state of the bypass heating circuit and the opening and closing state of the electric heating belt according to the outlet water temperature" further includes: when the heat pump unit stops running, if the outlet water temperature is greater than or equal to the second preset outlet water temperature and less than the first preset outlet water temperature, then the bypass heating circuit is controlled to be disconnected and the electric heating belt is controlled to be turned off, and the heat pump unit is controlled to run.

[0012] In a preferred embodiment of the above control method, when the heat pump unit is running and the outlet water temperature is greater than or equal to the second preset outlet water temperature and less than the first preset outlet water temperature, the control method further includes: obtaining the outlet water temperature of the condenser again; if the obtained outlet water temperature is greater than or equal to the third preset outlet water temperature, then controlling the heat pump unit to stop running and controlling the bypass heating circuit to connect; wherein, the third preset outlet water temperature is greater than the first preset outlet water temperature.

[0013] In the preferred embodiment of the above control method, the step of "selectively controlling the connection state of the bypass heating circuit and the opening and closing state of the electric heating belt according to the outlet water temperature" further includes: if the outlet water temperature is less than the second preset outlet water temperature when the heat pump unit stops running or is in standby mode, then the electric heating belt is controlled to turn on.

[0014] In a preferred embodiment of the above control method, when the heat pump unit is about to operate, the control method further includes: if the bypass heating circuit is connected and the outlet water temperature is greater than or equal to the second preset outlet water temperature, then the bypass heating circuit is controlled to disconnect.

[0015] With the above technical solution adopted, the heat pump unit of the present invention includes a refrigerant circulation loop and a bypass heating loop. A compressor and a condenser are arranged on the refrigerant circulation loop. At least a portion of the bypass heating loop is arranged in the condenser. A heating element is arranged on the bypass heating loop, located near the compressor, and configured to heat the refrigerant in the compressor. Based on the bypass heating loop, the present invention can effectively utilize the waste heat generated by the condenser condensing the refrigerant, using this waste heat to heat the refrigerant in the compressor, preventing the refrigerant from becoming liquid and dissolving in the refrigeration oil. This not only shortens the time required for the heat pump unit to restart but also effectively reduces costs and avoids resource waste. Attached Figure Description

[0016] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0017] Figure 1 This is a schematic diagram of the structure of the heat pump unit of the present invention;

[0018] Figure 2 This is a flowchart of the main steps of the control method of the present invention;

[0019] Figure 3 This is a flowchart illustrating the specific steps of a preferred embodiment of the control method of the present invention;

[0020] Figure label:

[0021] 1. Refrigerant circulation loop; 11. Compressor; 12. Condenser; 13. Throttling component; 14. Evaporator;

[0022] 2. Bypass heating circuit; 21. Shell-and-tube heat exchanger; 22. Solenoid control valve;

[0023] 3. Electric heating belt. Detailed Implementation

[0024] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the invention and are not intended to limit the scope of protection of the invention. Those skilled in the art can make adjustments as needed to adapt to specific applications. For example, the heat pump unit described in this invention can be a residential heat pump unit or a commercial heat pump unit; this is not limiting. Those skilled in the art can define the application of the control method of the present invention according to actual usage requirements. Such changes in the application do not deviate from the basic principles of the present invention and fall within the scope of protection of the present invention.

[0025] It should be noted that, in the description of this preferred embodiment, unless otherwise explicitly specified and limited, the terms "connection" and "linked" should be interpreted broadly. For example, they can refer to mechanical connections or electrical connections, direct connections or indirect connections through an intermediate medium, or connections within two components. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only, and those skilled in the art can understand the specific meaning of these terms in the present invention according to the specific circumstances.

[0026] Furthermore, it should be noted that although the various steps of the control method of the present invention are described in a specific order in the description of the present invention, these orders are not restrictive. Without departing from the basic principles of the present invention, those skilled in the art can perform the steps in different orders.

[0027] First refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of the heat pump unit of the present invention. Specifically, as shown... Figure 1 As shown, the heat pump unit of the present invention includes a refrigerant circulation loop 1 and a bypass heating loop 2. The refrigerant circulation loop 1 is equipped with a compressor 11, a condenser 12, a throttling component 13, and an evaporator 14. Those skilled in the art will understand that the specific structure of the throttling component 13 is not limiting; the throttling component 13 can be a capillary tube or an electronic expansion valve, and those skilled in the art can design it accordingly. Furthermore, it should be noted that the present invention does not impose any limitations on the specific structure of the compressor 11, condenser 12, and evaporator 14. The compressor 11 can be a fixed-frequency compressor or a variable-frequency compressor, and the condenser 12 and evaporator 14 can be finned heat exchangers or shell-and-tube heat exchangers; these are not limiting factors.

[0028] Furthermore, at least a portion of the bypass heating circuit 2 is disposed within the condenser 12, and a heating element is provided on the bypass heating circuit 2. This heating element is located near the compressor 11 and is configured to heat the refrigerant within the compressor 11. Based on the bypass heating circuit 2, this invention effectively utilizes the waste heat generated by the condenser 12 during refrigerant condensation. This waste heat is used to heat the refrigerant within the compressor 11, preventing the refrigerant from becoming liquid and dissolving in the refrigeration oil. This not only shortens the time required for the heat pump unit to restart but also effectively reduces costs and avoids resource waste.

[0029] It should be noted that the present invention does not impose any restrictions on the specific structure of the heating component. For example, the heating component can be a heating tube that can circulate heat exchange medium. In a preferred embodiment, the heating component is a shell-and-tube heat exchanger 21, which is coiled at the bottom of the compressor 11. The shell-and-tube heat exchanger 21 can circulate heat exchange medium (such as water) in the bypass heating circuit 2. The heat exchange medium in the bypass heating circuit 2 absorbs the heat generated after the refrigerant in the condenser 12 is condensed, so as to use the waste heat to fully heat the liquid refrigerant in the compressor 11 and turn it into a gaseous state. This can not only avoid liquid slugging in the compressor 11, but also effectively reduce costs.

[0030] Continue reading Figure 1 Preferably, the heat pump unit further includes an electric heating belt 3, which is disposed near the compressor 11. The placement of the electric heating belt 3 further ensures that there is no liquid refrigerant in the compressor 11 before the heat pump unit starts, avoiding liquid slugging in the compressor 11 and thus effectively ensuring the service life of the compressor 11. It should be noted that the specific placement of the electric heating belt 3 near the compressor 11 is not limiting. The electric heating belt 3 can be placed near the compressor 11 or coiled and wrapped around the compressor 11. These are not limiting, and those skilled in the art can set it according to the actual situation.

[0031] Furthermore, an electromagnetic control valve 22 is provided on the bypass heating circuit 2. The electromagnetic control valve 22 is located at the outlet of the condenser 12, and is configured to control the connection state of the bypass heating circuit 2. Of course, the specific type and structure of the electromagnetic control valve 22 are not limiting; those skilled in the art can set it according to actual conditions. In addition, a circulating water pump can also be provided on the bypass heating circuit 2. The circulating water pump can accelerate the flow rate of water in the bypass heating circuit 2 to improve the heat exchange effect between the shell-and-tube heat exchanger 21 and the refrigerant in the compressor 11. Of course, the specific structure and location of the circulating water pump are not limiting. For example, the circulating water pump can be located downstream of the electromagnetic control valve 22. When the bypass heating circuit 2 is connected, those skilled in the art can selectively turn on the circulating water pump according to actual conditions. When the bypass heating circuit 2 is not connected, the circulating water pump is in a closed state.

[0032] Preferably, a heat storage device can be provided in the condenser 12. The heat storage device can store the heat generated by the condenser 12 during the operation of the heat pump unit, so that when the heat pump unit stops running, the bypass heating circuit 2 can effectively utilize the heat energy stored in the heat storage device, which can further reduce energy consumption.

[0033] Furthermore, the heat pump unit also includes a temperature sensor and a controller. The temperature sensor is used to detect the outlet water temperature of the condenser 12. Those skilled in the art will understand that the specific type, structure, location, and number of the temperature sensor are not limiting; they can be set according to actual needs. The controller can acquire the detection results from the temperature sensor and can also control the on / off state of the heat pump unit, the on / off state of the electric heating belt 3, and the connection state of the bypass heating circuit 2, etc., which are not limiting. Those skilled in the art will understand that this invention does not impose any limitations on the specific structure and model of the controller, and the controller can be either the original controller of the heat pump unit or a controller separately set up to execute the control method of this invention. Those skilled in the art can set the structure and model of the controller according to actual usage requirements.

[0034] First refer to Figure 2 , Figure 2 This is a flowchart of the main steps of the control method of the present invention. Figure 2 As shown, based on the heat pump unit described in the above embodiments, the control method of the present invention mainly includes the following steps:

[0035] S1: Obtain the outlet water temperature of the condenser;

[0036] S2: Selectively control the connection status of the bypass heating circuit and the on / off status of the electric heating belt according to the outlet water temperature.

[0037] First, in step S1, the controller acquires the outlet water temperature of the condenser 12. Those skilled in the art will understand that the outlet water temperature of the condenser 12 can be a real-time temperature or an average outlet water temperature over a period of time; neither is limiting. Preferably, the outlet water temperature of the condenser 12 is a real-time temperature, so that the real-time status of the condenser 12 can be obtained, thereby facilitating the determination that the water temperature in the bypass heating circuit 2 meets the requirements for heating the refrigerant in the compressor 11.

[0038] Next, in step S2, the controller selectively controls the connection state of the bypass heating circuit 2 and the opening and closing state of the electric heating belt 3 according to the outlet water temperature, so that the waste heat of the condenser 12 can be fully utilized to heat the refrigerant in the compressor 11 instead of using the electric heating belt 3 to heat the refrigerant in the compressor 11. This can avoid energy waste, eliminate potential electrical hazards, and ensure personnel safety.

[0039] See next Figure 3 , Figure 3 This is a flowchart illustrating the specific steps of a preferred embodiment of the control method of the present invention. Figure 3 As shown, based on the heat pump unit described in the above embodiments, the control method of the preferred embodiment of the present invention includes the following steps:

[0040] S101: Obtain the outlet water temperature of the condenser;

[0041] S102: When the heat pump unit stops running or is in standby mode, if the outlet water temperature is greater than or equal to the first preset outlet water temperature, the bypass heating circuit is connected and the electric heating belt is not turned on.

[0042] S103: When the heat pump unit stops running, if the outlet water temperature is greater than or equal to the second preset outlet water temperature and less than the first preset outlet water temperature, the bypass heating circuit is disconnected and the electric heating belt is not turned on, and the heat pump unit is turned on.

[0043] S104: Obtain the condenser outlet water temperature again;

[0044] S105: If the outlet water temperature obtained again is greater than or equal to the third preset outlet water temperature, control the heat pump unit to stop running and control the bypass heating circuit to be connected.

[0045] S106: When the heat pump unit stops running or is in standby mode, if the outlet water temperature is lower than the second preset outlet water temperature, the electric heating belt will be turned on.

[0046] S107: When the heat pump unit is about to start, if the outlet water temperature is greater than or equal to the second preset outlet water temperature, the bypass heating circuit will be disconnected.

[0047] First, in step S101, the controller acquires the outlet water temperature of the condenser 12. Those skilled in the art will understand that the outlet water temperature of the condenser 12 can be a real-time temperature or an average outlet water temperature over a period of time; neither is limiting. Preferably, the outlet water temperature of the condenser 12 is a real-time temperature, so that the real-time status of the condenser 12 can be obtained, thereby facilitating the determination that the water temperature in the bypass heating circuit 2 meets the requirements for heating the refrigerant in the compressor 11.

[0048] Next, the controller selectively controls the connection state of the bypass heating circuit 2 and the opening and closing state of the electric heating belt 3 according to the outlet water temperature, so that the waste heat of the condenser 12 can be fully utilized to heat the refrigerant in the compressor 11 instead of using the electric heating belt 3 to heat the refrigerant in the compressor 11. This can avoid energy waste, eliminate potential electrical hazards, and ensure personnel safety.

[0049] Specifically, in step S102, when the heat pump unit stops running or is in standby mode, if the outlet water temperature is greater than or equal to the first preset outlet water temperature, it means that the current condenser 12 can transfer the heat of the refrigerant in the refrigerant circulation loop 1 to the water in the bypass heating loop 2, and the temperature of the water after heat exchange is sufficient to evaporate the refrigerant in the compressor 11. Then the controller controls the bypass heating loop 2 to be connected and controls the electric heating belt 3 to be closed, that is, controls the electromagnetic control valve 22 to be opened so that the bypass heating loop 2 is connected. In this case, it can ensure that the refrigerant in the compressor 11 will not become liquid and dissolve in the refrigeration oil, reduce the risk of electrical hazards, ensure personnel safety, effectively reduce costs, and improve the user experience.

[0050] Furthermore, in step S103, when the heat pump unit stops operating, if the outlet water temperature is greater than or equal to the second preset outlet water temperature and less than the first preset outlet water temperature, it indicates that although the water temperature in the bypass heating circuit 2 can heat the refrigerant in the compressor 11, it is only just enough to make the refrigerant in the compressor 11 insoluble in the refrigeration oil. As the bypass heating circuit 2 continues to circulate, the refrigerant in the compressor 11 is likely to become liquid and mix with the refrigeration oil. At this time, the controller controls the bypass heating circuit 2 to be disconnected and controls the electric heating belt 3 to be turned off, controlling the heat pump unit to operate, so that the condenser 12 can accumulate more heat from the refrigerant circulation circuit 1 in the condenser 12, so that when the heat pump unit stops operating and the bypass heating circuit 2 is connected, the residual heat can be fully utilized to heat the refrigerant in the compressor 11. This setting method can not only enable the heat pump unit to operate to meet the user's normal heating or cooling needs, but also reduce electrical hazards and ensure personnel safety.

[0051] Preferably, in step S104, when the heat pump unit is running and the outlet water temperature is greater than or equal to the second preset outlet water temperature but less than the first preset outlet water temperature, the controller again obtains the outlet water temperature of the condenser 12, and controls the connection state of the bypass heating circuit 2 according to the again obtained outlet water temperature. Specifically, in step S105, if the again obtained outlet water temperature is greater than or equal to the third preset outlet water temperature, the controller stops the heat pump unit and controls the bypass heating circuit 2 to connect; wherein, the third preset outlet water temperature is greater than the first preset outlet water temperature. Regarding step S105, those skilled in the art should understand that the purpose of starting the heat pump unit here is to increase the waste heat in the condenser 12 so that the bypass heating circuit 2 can use this waste heat to heat the refrigerant in the compressor 11. Of course, during the operation of the heat pump unit, the heat pump unit can be in normal operating condition to provide users with normal cooling or heating needs. That is, the operation of the heat pump unit here is carried out under the condition that the user has no unnecessary cooling or heating needs. If the outlet water temperature of the condenser 12 is obtained again and is greater than the third preset outlet water temperature, the controller can shut down the heat pump unit according to the actual situation.

[0052] It should be noted that the present invention does not impose any restrictions on the specific setting values ​​of the first preset outlet water temperature, the second preset outlet water temperature, and the third preset temperature. Those skilled in the art can set them according to actual conditions. Preferably, the third preset outlet water temperature is the sum of the first preset outlet water temperature and 10°C, so that the bypass heating circuit 2 heats the refrigerant in the compressor 11 for a longer period of time before the heat pump unit stops running and starts up again, that is, further effectively avoiding potential electrical hazards and reducing costs.

[0053] In addition, the condenser 12 may also include a heat storage device, which can store the heat released by the condenser 12 during the operation of the heat pump unit to supply the bypass heating circuit 2. Of course, this configuration is not limiting, and those skilled in the art can configure it according to actual conditions.

[0054] Further, in step S106, when the heat pump unit stops operating or is in standby mode, if the outlet water temperature is lower than the second preset outlet water temperature, it indicates that the current bypass heating circuit 2 is insufficient to maintain the refrigerant in the compressor 11 in a gaseous state. In this case, the controller controls the electric heating belt 3 to turn on, ensuring that the heat pump unit can start immediately when the user turns it on, and that the compressor 11 will not experience liquid slugging. Regarding step S106, it should be noted that when the electric heating belt 3 is on, those skilled in the art can selectively connect the bypass heating circuit 2 according to the actual situation. For example, if the temperature of the heat exchange medium in the bypass heating circuit 2 is higher than the temperature inside the compressor 11, the bypass heating circuit 2 can be connected to minimize the power consumption of the electric heating belt 3; if the temperature of the heat exchange medium in the bypass heating circuit 2 is lower than the temperature inside the compressor 11, the bypass heating circuit 2 should not be connected to avoid the electric heating belt 3 generating greater power consumption.

[0055] Further, in step S107, when the heat pump unit is about to operate, if the bypass heating circuit 2 is connected and the outlet water temperature is greater than or equal to the second preset outlet water temperature, the controller controls the bypass heating circuit 2 to disconnect. That is, when the heat pump unit is operating normally, the bypass heating circuit 2 is not connected to ensure the normal operation of the heat pump unit. Also, when the heat pump unit is operating normally, the temperature inside the compressor 11 is high, ensuring that the refrigerant exists in a gaseous state. In addition, it is necessary to determine whether the outlet water temperature is greater than or equal to the second preset outlet water temperature. If the outlet water temperature is less than the second preset outlet water temperature, liquid refrigerant exists inside the compressor 11. If the heat pump unit is turned on, the compressor 11 may experience liquid slugging, which will shorten the service life of the compressor 11. If the outlet water temperature is greater than or equal to the second preset outlet water temperature, it can effectively ensure that the compressor 11 will not experience liquid slugging. This setting method can effectively guarantee the service life of the compressor 11.

[0056] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A control method of a heat pump unit, characterized by, The heat pump unit comprises a refrigerant circulation loop and a bypass heating loop, the refrigerant circulation loop is provided with a compressor and a condenser, at least a part of the bypass heating loop is arranged in the condenser, the bypass heating loop is provided with a heating member, the heating member is arranged near the compressor, the heating member is arranged to heat the refrigerant in the compressor, an electric heating belt is arranged near the compressor, The control method comprises: obtaining the outlet water temperature of the condenser; selectively controlling the communication state of the bypass heating loop and the on-off state of the electric heating belt according to the outlet water temperature, which comprises: if the outlet water temperature is greater than or equal to a first preset outlet water temperature when the heat pump unit is in a stop state or a standby state, it indicates that the temperature of the refrigerant medium in the bypass heating loop after heat exchange can make the refrigerant in the compressor evaporate, then the bypass heating loop is controlled to be connected and the electric heating belt is controlled not to be turned on.

2. The control method according to claim 1, characterized by, The step of "selectively controlling the communication state of the bypass heating loop and the on-off state of the electric heating belt according to the outlet water temperature" further comprises: if the outlet water temperature is greater than or equal to a second preset outlet water temperature and less than the first preset outlet water temperature when the heat pump unit is in a stop state, the bypass heating loop is controlled not to be connected and the electric heating belt is controlled not to be turned on, and the heat pump unit is controlled to be operated; if the outlet water temperature is less than the second preset outlet water temperature, it indicates that the current bypass heating loop is insufficient to make the refrigerant in the compressor maintain gaseous state.

3. The control method according to claim 2, characterized by, When the heat pump unit is operated and the outlet water temperature is greater than or equal to the second preset outlet water temperature and less than the first preset outlet water temperature, the control method further comprises: obtaining the outlet water temperature of the condenser again; if the outlet water temperature obtained again is greater than or equal to a third preset outlet water temperature, the heat pump unit is controlled to be stopped and the bypass heating loop is controlled to be connected; wherein the third preset outlet water temperature is greater than the first preset outlet water temperature.

4. The control method according to claim 2, characterized by, The step of "selectively controlling the communication state of the bypass heating loop and the on-off state of the electric heating belt according to the outlet water temperature" further comprises: if the outlet water temperature is less than the second preset outlet water temperature when the heat pump unit is in a stop state or a standby state, the electric heating belt is controlled to be turned on.

5. The control method according to any one of claims 2 to 4, characterized by, When the heat pump unit is about to be operated, the control method further comprises: if the bypass heating loop is connected and the outlet water temperature is greater than or equal to the second preset outlet water temperature, the bypass heating loop is controlled to be disconnected.

6. The control method according to claim 1, characterized by The bypass heating loop is provided with an electromagnetic control valve, the electromagnetic control valve is arranged at the outlet of the condenser, and the electromagnetic control valve is arranged to control the communication state of the bypass heating loop.

7. The control method according to claim 1, characterized by, The heating member is a jacketed heat exchanger.

Images