Start-up control method for high-temperature heat pump with pressure maintaining valve

Abstract

The invention relates to the technical field of heating and water supply systems, in particular to a starting control method for a high-temperature heat pump with a pressure maintaining valve, which comprises the steps that a high-temperature compressor, an evaporator, a condenser and a throttling device are arranged on a high-temperature circulation loop, and the system monitors the suction temperature and suction pressure in real time, dynamically adjusts operating parameters, improves the energy utilization efficiency of the heat pump and reduces the energy consumption. The energy consumption is reduced. The pressure in the system is kept stable through the pressure maintaining valve, and unstable operation of the heat pump caused by pressure fluctuation is avoided. The auxiliary heater rapidly increases the temperature of the high-temperature compressor and the oil separator when the system is started, the high-temperature compressor operates at the optimal working temperature, and energy consumption and abrasion during starting are reduced. Judgment is made according to the external environment temperature and various temperature and pressure values of the system, and heat supplementation is conducted on the specific position of the unit before the unit is started and in the starting process. The liquid refrigerant accumulated in the high-temperature compressor is gasified, and it is guaranteed that the unit is stably started and loaded after being shut down for a long time at various environment temperatures.

Description

Technical Field

[0001] The invention relates to the technical field of heating water supply systems, and in particular to a method for controlling the startup of a high-temperature heat pump with a pressure maintaining valve. Background Art

[0002] Conventional high-temperature heat pump systems are generally equipped with a pressure-maintaining valve to protect the normal oil return of the high-temperature compressor. During normal startup, if the high and low pressure differences are not established, the exhaust gas of the high-temperature compressor will accumulate in the oil separator. Since the exhaust temperature of the high-temperature heat pump unit is much higher than the ambient temperature, it is easy for the high-temperature gas accumulated in the oil separator to exchange heat with the surrounding environment, so that during the startup process, the refrigerant condenses into liquid in the oil separator, and the unit will have low pressure and other faults, leading to machine failure. In addition, the water temperature inside the two devices of the high-temperature screw unit is generally higher than the ambient temperature most of the time, so that the temperature of the high-temperature compressor is lower than the temperature in the evaporator after the unit is shut down, causing the refrigerant to migrate into the cavity of the high-temperature compressor, causing the high-temperature compressor to run with liquid for a long time when it is started, seriously endangering the service life of the high-temperature compressor. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a high-temperature heat pump startup control method that provides a method for judging the external ambient temperature and various temperature and pressure values ​​of the system before and during the startup of the unit by adding heat to specific positions of the unit, thereby gasifying the liquid refrigerant accumulated inside the high-temperature compressor and ensuring the stable startup and loading of the unit at various ambient temperatures and after long-term shutdown.

[0004] The technical problem to be solved by the present invention is achieved through the following technical solutions: a high-temperature heat pump startup control method with a pressure maintaining valve, comprising a high-temperature circulation loop, on which a high-temperature compressor, an evaporator, a condenser and a throttling device are arranged, and an intake temperature sensor and an intake pressure sensor are arranged in sequence along the liquid outlet direction of the pipeline between the evaporator and the high-temperature compressor, the intake temperature sensor detects the intake temperature Ts of the high-temperature compressor, and the intake pressure sensor detects the intake pressure Ps of the high-temperature compressor;

[0005] The high-temperature compressor is also connected to an oil circulation circuit for oil separation and oil return of the high-temperature compressor. The oil circulation circuit is provided with an oil separator and an oil cooler. A pressure maintaining valve is provided on the refrigerant circulation circuit between the liquid outlet of the oil separator and the liquid inlet of the condenser. The top of the pressure maintaining valve is connected to the suction side of the high-temperature compressor. A pressure sensor is provided on the oil separator to detect the internal pressure Po of the oil separator. A temperature sensor is provided on the oil separator to detect the external surface temperature To of the oil separator.

[0006] By installing a pressure maintaining valve between the oil separator and the condenser, the pressure in the system can be effectively kept stable, avoiding unstable operation of the heat pump caused by pressure fluctuations.

[0007] The system dynamically adjusts the operating parameters according to the real-time monitoring of the suction temperature (Ts) and suction pressure (Ps), thereby improving the energy efficiency of the heat pump and reducing energy consumption. The pressure (Po) and temperature (To) inside the oil separator are monitored in real time. In the event of abnormal conditions, the system responds promptly to prevent equipment damage or failure.

[0008] Auxiliary heaters are installed on the high-temperature compressor and oil separator. The auxiliary heaters can quickly increase the temperature of the high-temperature compressor and oil separator when the system starts, ensuring that the high-temperature compressor operates at the optimal operating temperature and reducing energy consumption and wear during startup. At the same time, by accurately controlling the working time and power of the auxiliary heater, the system can effectively save energy, reduce operating costs, and avoid energy waste caused by excessive heating.

[0009] The auxiliary heater and each sensor are respectively connected to the controller through communication, and the controller is also connected to the ambient temperature sensor through communication. The ambient temperature sensor detects the ambient temperature Th. The controller judges whether to turn on or off the auxiliary heater to realize the startup control logic through the data of the high-temperature compressor suction pressure Ps, the high-temperature compressor suction temperature Ts, the oil separator internal pressure Po, the oil separator outer surface temperature To and the ambient temperature Th collected by each sensor; the following steps are included:

[0010] S1: Before the system is put into operation, the start-up conditions of the high-temperature compressor are determined. The controller receives the high-temperature compressor suction pressure Ps and the oil separator internal pressure Po collected by the sensor, and calculates the saturation temperature Tse corresponding to the high-temperature compressor suction pressure Ps and the saturation temperature Toe corresponding to the oil separator internal pressure Po;

[0011] S2: The power-on signal is transmitted to the controller, and the controller performs a logical judgment on Tse and Toe;

[0012] S3: In step S2, when Ts>Tse+1 and To>Toe+1 are satisfied, the high temperature compressor starts and enters the loading logic;

[0013] S4: In step S2, when Ts<Tse+1 and To<Toe+1, or when Ts>Tse+1 and To<Toe+1, or when Ts<Tse+1 and To>Toe+1, the high-temperature compressor is not started, and the auxiliary heater is turned on to heat the high-temperature compressor and the oil separator to supplement heat energy;

[0014] S5: In step S3, during the loading process of the high-temperature compressor, the controller detects the high-temperature compressor suction pressure Ps, the high-temperature compressor suction temperature Ts, the oil separator internal pressure Po, the oil separator outer surface temperature To and the ambient temperature Th in real time. When the high-temperature compression load is loaded to more than 50%, a logical judgment is made on Ts and To, and the cycle enters step S2 to determine whether the unit turns off the auxiliary heater and enters energy regulation;

[0015] S6: In step S5, when Ts>Tse+1 and To>Toe+1 are satisfied, but Po-Ps<set value, the auxiliary heater continues to supplement heat energy to the heat pump system, and the high-temperature compressor continues to execute the loading logic.

[0016] S7: In step S5, when Ts>Tse+1 and To>Toe+1 are satisfied, and Po-Ps≥set value, and lasts for the set time, turn off the auxiliary heater, complete the startup procedure, and enter energy regulation.

[0017] As a further solution of the present invention, the set value is the product of 4 kg pressure and the pressure compensation coefficient corresponding to the ambient temperature, and the pressure compensation coefficient corresponding to the ambient temperature Th is 0.8-1.15.

[0018] The dynamic adjustment of the pressure compensation coefficient enables the system to automatically adapt to changes in ambient temperature, thereby maintaining stable pressure output in the event of climate change or operating condition fluctuations, reducing system failure rates. The system can achieve more precise pressure control, ensuring that the equipment can operate stably under different environmental conditions.

[0019] As a further solution of the present invention, the set time is 10S-30S.

[0020] As a further solution of the present invention, a first stop valve, a regulating valve and a second stop valve are provided on the high temperature circulation loop between the condenser and the evaporator along the liquid outlet direction. The regulating valve allows the liquid flow to be accurately adjusted, thereby meeting the flow requirements of the system under different working conditions and ensuring that the system operates in the best state.

[0021] Through the effective control of flow and pressure, the heat exchange efficiency of the system can be improved, ensuring that the heat transfer between the evaporator and the condenser is more efficient and reducing energy consumption. After setting the valve and, maintenance and cleaning work becomes more convenient, and necessary inspections and replacements can be carried out without interrupting the operation of the entire system, which improves the maintainability of the system.

[0022] As a further solution of the present invention, a fourth stop valve is sequentially provided along the oil outlet direction on the oil circulation loop between the oil separator outlet and the oil cooler, and an oil flow meter and a third stop valve are sequentially provided along the oil outlet direction on the oil circulation loop between the oil outlet of the oil cooler and the oil return port of the high-temperature compressor.

[0023] As a further solution of the present invention, the auxiliary heater is an electric heater.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides a high-temperature heat pump startup control method with a pressure maintaining valve, comprising a high-temperature circulation loop, on which a high-temperature compressor, an evaporator, a condenser and a throttling device are provided, and an intake temperature sensor and an intake pressure sensor are provided in sequence along the liquid outlet direction of the pipeline between the evaporator and the high-temperature compressor, the intake temperature sensor detects the intake temperature Ts of the high-temperature compressor, and the intake pressure sensor detects the intake pressure Ps of the high-temperature compressor; the system dynamically adjusts the operating parameters according to the real-time monitoring of the intake temperature (Ts) and the intake pressure (Ps), thereby improving the energy utilization efficiency of the heat pump and reducing energy consumption.

[0026] The high-temperature compressor is also connected to an oil circulation loop for oil separation and oil return of the high-temperature compressor. The oil circulation loop is equipped with an oil separator and an oil cooler. A pressure maintaining valve is provided on the refrigerant circulation loop between the liquid outlet of the oil separator and the liquid inlet of the condenser, which can effectively maintain the pressure stability in the system and avoid unstable operation of the heat pump caused by pressure fluctuations. The pressure (Po) and temperature (To) inside the oil separator are monitored in real time. In the event of abnormal conditions, the system responds promptly to prevent equipment damage or failure.

[0027] Auxiliary heaters are installed on the high-temperature compressor and oil separator. The auxiliary heaters can quickly increase the temperature of the high-temperature compressor and oil separator when the system starts, ensuring that the high-temperature compressor operates at the optimal operating temperature and reducing energy consumption and wear during startup. At the same time, by accurately controlling the working time and power of the auxiliary heater, the system can effectively save energy, reduce operating costs, and avoid energy waste caused by excessive heating.

[0028] Based on the external environment temperature and various temperature and pressure values ​​of the system, heat is added to specific positions of the unit before and during the startup of the unit. This allows the liquid refrigerant accumulated inside the high-temperature compressor to be vaporized, ensuring stable startup and loading of the unit at various ambient temperatures and after long-term shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of a high temperature heat pump system of the present invention;

[0030] Figure 2 This is a high-temperature heat pump startup control flow chart of the present invention.

[0031] Among them: 1-condenser, 2-oil separator, 201-temperature sensor, 202-pressure sensor, 203-intake pressure sensor, 204-intake temperature sensor, 205-second stop valve, 206-regulating valve, 207-first stop valve, 3-pressure maintaining valve, 4-oil cooler, 401-fourth stop valve, 402-third stop valve, 403-oil flow meter, 5-high temperature compressor, 6-auxiliary heater, 7-evaporator, 8-high temperature circulation loop, 9-controller. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] The serial numbers of the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] As attached Figure 1 -Attached Figure 2As shown, a high-temperature heat pump startup control method with a pressure maintaining valve includes a high-temperature circulation loop 8, a circulating refrigerant is provided in the high-temperature circulation loop, a high-temperature compressor 5, an evaporator 7, a condenser 1 and a throttling device are provided on the high-temperature circulation loop, and an intake temperature sensor 204 and an intake pressure sensor 203 are provided in sequence along the liquid outlet direction of the pipeline between the evaporator and the high-temperature compressor, the intake temperature sensor detects the intake temperature Ts of the high-temperature compressor, and the intake pressure sensor detects the intake pressure Ps of the high-temperature compressor;

[0036] The high-temperature compressor is also connected to an oil circulation circuit for oil separation and oil return of the high-temperature compressor. The oil circulation circuit is provided with an oil separator 2 and an oil cooler 4. The oil circulation circuit between the oil separator oil outlet and the oil cooler is provided with a fourth stop valve 401 in sequence along the oil outlet direction. When the system is in normal working state, the fourth stop valve is opened, and the hydraulic oil in the oil separator enters the oil cooler for heat exchange. The oil circulation circuit between the oil cooler oil outlet and the high-temperature compressor oil return port is provided with an oil flow meter 403 and a third stop valve 402 in sequence along the oil outlet direction. After the hydraulic oil is cooled by the oil cooler, before it flows back into the high-temperature compressor, the third stop valve is opened, and the hydraulic oil flows back to the high-temperature compressor. The oil flow meter measures the flow rate of the hydraulic oil return.

[0037] A pressure maintaining valve 3 is provided on the refrigerant circulation loop between the liquid outlet of the oil separator and the liquid inlet of the condenser. The top of the pressure maintaining valve 3 is connected to the suction side of the high-temperature compressor. A pressure sensor is provided on the oil separator to detect the internal pressure Po of the oil separator. A temperature sensor 201 is provided on the oil separator to detect the external surface temperature To of the oil separator. The pressure maintaining valve 3 transfers the excess pressure to the high-temperature compressor, thereby maintaining the pressure in the system stable and avoiding unstable operation of the heat pump caused by pressure fluctuations.

[0038] The system dynamically adjusts the operating parameters according to the real-time monitoring of the suction temperature (Ts) and suction pressure (Ps), and the heat pump system has low energy consumption. The pressure (Po) and temperature (To) inside the oil separator are monitored in real time. In the event of abnormal conditions, the system responds promptly to prevent equipment damage or failure.

[0039] The high temperature circulation loop between the condenser and the evaporator is provided with a first stop valve 207, a regulating valve 206 and a second stop valve 205 along the liquid outlet direction. The regulating valve 206 allows the liquid flow to be precisely adjusted, thereby meeting the flow requirements of the system under different working conditions and ensuring that the system operates in the best state.

[0040] Through the effective control of flow and pressure, the heat exchange efficiency of the system can be improved, ensuring that the heat transfer between the evaporator and the condenser is more efficient and reducing energy consumption. After setting the valve and, maintenance and cleaning work becomes more convenient, and necessary inspections and replacements can be carried out without interrupting the operation of the entire system, which improves the maintainability of the system.

[0041] The high-temperature compressor and the oil separator are both provided with an auxiliary heater 6, and the auxiliary heater 6 is an electric heater.

[0042] Regardless of the ambient temperature or after a long shutdown, when the system is started, the auxiliary heater 6 is started to quickly replenish the system with heat, quickly increase the temperature of the high-temperature compressor 5 and the oil separator 2, reach the optimal working temperature of the high-temperature compressor, and start the high-temperature compressor stably. At the same time, by accurately controlling the working time and power of the auxiliary heater, the system can operate stably under low energy consumption.

[0043] The auxiliary heater 6 and each sensor are respectively connected to the controller 9 through communication. The controller is also connected to the ambient temperature sensor. The ambient temperature sensor detects the ambient temperature Th. The controller judges whether to turn on or off the auxiliary heater to realize the startup control logic through the data of the high-temperature compressor suction pressure Ps, the high-temperature compressor suction temperature Ts, the oil separator internal pressure Po, the oil separator outer surface temperature To and the ambient temperature Th collected by each sensor; the following steps are included:

[0044] S1: Before the system is operated, the high-temperature compressor start-up condition is determined. The controller 9 receives the high-temperature compressor suction pressure Ps and the oil separator internal pressure Po collected by the sensor, and calculates the saturation temperature Tse corresponding to the high-temperature compressor suction pressure Ps and the saturation temperature Toe corresponding to the oil separator internal pressure Po;

[0045] S2: The power-on signal is transmitted to the controller 9, and the controller performs a logical judgment on Tse and Toe;

[0046] S3: In step S2, when Ts>Tse+1 and To>Toe+1 are satisfied, the high temperature compressor 5 starts and enters the loading logic;

[0047] S4: In step S2, when Ts<Tse+1 and To<Toe+1, or when Ts>Tse+1 and To<Toe+1, or when Ts<Tse+1 and To>Toe+1, the high-temperature compressor 5 is not started, and the auxiliary heater is turned on to heat the high-temperature compressor and the oil separator to supplement heat energy;

[0048] S5: In step S3, during the loading process of the high-temperature compressor 5, the controller detects the high-temperature compressor suction pressure Ps, the high-temperature compressor suction temperature Ts, the oil separator internal pressure Po, the oil separator outer surface temperature To and the ambient temperature Th in real time. When the high-temperature compression load is loaded to more than 50%, a logical judgment is made on Ts and To, and the cycle enters step S2 to determine whether the unit turns off the auxiliary heater and enters energy regulation;

[0049] S6: In step S5, when Ts>Tse+1 and To>Toe+1 are satisfied, but Po-Ps<set value, the set value is the product of 4 kg pressure and the pressure compensation coefficient corresponding to the ambient temperature, and the pressure compensation coefficient corresponding to the ambient temperature Th is 0.9. According to the needs of the system, the pressure compensation coefficient is dynamically adjusted so that the system can automatically adapt to the changes in ambient temperature, thereby maintaining a stable pressure output in the case of climate change or operating fluctuations, and reducing the system failure rate. The system can achieve more precise pressure control to ensure that the equipment can operate stably under different environmental conditions.

[0050] Among them, for the pressure compensation coefficient, under certain measurement or experimental conditions, changes in ambient temperature will affect the measured pressure value. In order to obtain accurate data, corresponding compensation is required. The pressure compensation coefficient is usually obtained through experiments or theoretical calculations, and often depends on the specific gas properties and temperature range. In practical applications, specific formulas or reference tables can be used to obtain the corresponding pressure compensation coefficient.

[0051] The auxiliary heater 6 continues to supplement the heat energy to the heat pump system, and the high-temperature compressor continues to execute the loading logic.

[0052] S7: In step S5, when Ts>Tse+1 and To>Toe+1 are satisfied, and Po-Ps≥set value, and lasts for the set time, the set time is 20S, and the set time can be adjusted within the range of 10-30 seconds according to actual needs, turn off the auxiliary heater 6, complete the startup procedure, and enter energy regulation.

[0053] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for controlling the startup of a high-temperature heat pump with a pressure maintaining valve, characterized in that: The invention comprises a high-temperature circulation loop (8), wherein a high-temperature compressor (5), an evaporator (7), a condenser (1) and a throttling device are provided on the high-temperature circulation loop; an intake temperature sensor (204) and an intake pressure sensor (203) are provided in sequence along the liquid outlet direction of the pipeline between the evaporator and the high-temperature compressor; the intake temperature sensor (204) detects the intake temperature Ts of the high-temperature compressor, and the intake pressure sensor (203) detects the intake pressure Ps of the high-temperature compressor; The high-temperature compressor (5) is also connected to an oil circulation circuit for oil separation and oil return of the high-temperature compressor. The oil circulation circuit is provided with an oil separator (2) and an oil cooler (4). A pressure maintaining valve (3) is provided on the refrigerant circulation circuit between the liquid outlet of the oil separator and the liquid inlet of the condenser. The top of the pressure maintaining valve is connected to the suction side of the high-temperature compressor. A pressure sensor (202) is provided on the oil separator to detect the internal pressure Po of the oil separator. A temperature sensor (201) is provided on the oil separator to detect the external surface temperature To of the oil separator. The high-temperature compressor and the oil separator are both provided with an auxiliary heater (6), the auxiliary heater and each sensor are respectively connected to a controller (9) via communication, the controller is also connected to an ambient temperature sensor via communication, the ambient temperature sensor detects an ambient temperature Th, the controller judges whether to turn on or off the auxiliary heater (6) based on data of the high-temperature compressor suction pressure Ps, the high-temperature compressor suction temperature Ts, the oil separator internal pressure Po, the oil separator outer surface temperature To and the ambient temperature Th collected by each sensor, so as to realize the startup control logic; the following steps are included: S1: Before the system is put into operation, the start-up condition of the high-temperature compressor is determined. The controller (9) receives the high-temperature compressor suction pressure Ps and the oil separator internal pressure Po collected by the sensor, and calculates the saturation temperature Tse corresponding to the high-temperature compressor suction pressure Ps and the saturation temperature Toe corresponding to the oil separator internal pressure Po; S2: The power-on signal is transmitted to the controller (9), and the controller performs a logical judgment on Tse and Toe; S3: In step S2, when Ts>Tse+1 and To>Toe+1 are satisfied, the high temperature compressor (5) starts and enters the loading logic; S4: In step S2, when Ts<Tse+1 and To<Toe+1, or when Ts>Tse+1 and To<Toe+1, or when Ts<Tse+1 and To>Toe+1, the high-temperature compressor (5) is not started, and the auxiliary heater (6) is turned on to heat the high-temperature compressor (5) and the oil separator (2) to supplement thermal energy; S5: In step S3, during the loading process of the high-temperature compressor (5), the controller detects in real time the suction pressure Ps of the high-temperature compressor, the suction temperature Ts of the high-temperature compressor, the internal pressure Po of the oil separator, the external surface temperature To of the oil separator, and the ambient temperature Th. When the high-temperature compression load is loaded to more than 50%, a logical judgment is made on Ts and To, and the cycle enters step S2 to determine whether the unit turns off the auxiliary heater and enters energy regulation; S6: In step S5, when Ts>Tse+1 and To>Toe+1 are satisfied, but Po-Ps<set value, the auxiliary heater (6) continues to supplement heat energy to the heat pump system, and the high-temperature compressor (5) continues to execute the loading logic. S7: In step S5, when Ts>Tse+1 and To>Toe+1 are satisfied, and Po-Ps≥set value, and lasts for the set time, the auxiliary heater (6) is turned off, the startup procedure is completed, and energy regulation is entered.

2. The method for starting up a high-temperature heat pump with a pressure maintaining valve according to claim 1, characterized in that: The set value is the product of 4 kg pressure and the pressure compensation coefficient corresponding to the ambient temperature, and the pressure compensation coefficient corresponding to the ambient temperature Th is 0.8-1.

15.

3. The method for controlling the startup of a high-temperature heat pump with a pressure maintaining valve according to claim 1, characterized in that: The setting time is 10S-30S.

4. The method for controlling the startup of a high-temperature heat pump with a pressure maintaining valve according to claim 1, characterized in that: A first stop valve (207), a regulating valve (206) and a second stop valve (205) are provided on the high-temperature circulation loop between the condenser and the evaporator along the liquid outlet direction.

5. The method for controlling the startup of a high-temperature heat pump with a pressure maintaining valve according to claim 1, characterized in that: The oil circulation loop between the oil outlet of the oil separator and the oil cooler is provided with a fourth stop valve (401) in sequence along the oil outlet direction, and the oil circulation loop between the oil outlet of the oil cooler and the oil return port of the high-temperature compressor is provided with an oil flow meter (403) and a third stop valve (402) in sequence along the oil outlet direction.

6. The method for starting up a high-temperature heat pump with a pressure maintaining valve according to claim 1, characterized in that: The auxiliary heater (6) is an electric heater.

Images