Circulating type steam heat pump unit and control method thereof

Abstract

The invention relates to the technical field of heat pump units, and discloses a circulating type steam heat pump unit and a control method thereof.The circulating type steam heat pump unit effectively solves the technical problem that a compressor of a traditional unit is insufficient in cooling by constructing a linkage structure of oil way circulation and water side heat exchange. Accurate cooling is directly carried out on the high-temperature operation working condition of the compressor, the damage risk caused by overheating of the compressor and accessories is greatly reduced, and the operation reliability of a unit is remarkably improved; meanwhile, heat generated in the oil way cooling process is efficiently recycled for steam water replenishing and preheating, heat waste caused by a traditional external cooling mode is avoided, the heating capacity and heating efficiency of the unit are improved, and overall energy consumption is reduced; the electric connection design of the control device and all the mechanisms lays a solid structure foundation for subsequent accurate regulation and control, it is guaranteed that parameters in all links of cooling, preheating and steam production are highly matched, it is guaranteed that all the mechanism units of the circulating steam heat pump unit operate cooperatively and orderly, and the stability of the unit during working is improved.

Description

Technical Field

[0001] This invention relates to the field of heat pump unit technology, and in particular to a circulating steam heat pump unit and its control method. Background Technology

[0002] A steam heat pump unit is an energy-saving device that uses the reverse Carnot cycle principle to convert low-grade heat energy into high-grade heat energy to produce steam by consuming a small amount of high-grade energy. Currently, there are conventional products that can produce high-temperature steam through heat pump cycles.

[0003] However, conventional steam heat pump units of this type require the generation of steam, with operating condensing temperatures as high as 100℃~120℃ and above, and exhaust temperatures reaching 130~150℃. The operating conditions are extremely harsh, and the compressor and its components are prone to overheating and damage due to insufficient cooling. To solve this problem, some systems use oil cooling, but usually rely on external cooling water for oil cooling. Although this can reduce the oil temperature, a large amount of heat is lost during the cooling process, causing the heating capacity of the heat pump system to decrease by 10%~20% due to the oil cooling process. This makes it difficult to improve the energy efficiency of the heat pump unit, resulting in low efficiency and high energy consumption.

[0004] Although some conventional steam heat pump units use heat recovery from the oil cooler for steam makeup water, the amount of recovered hot water often does not match the amount of steam makeup water. This is mainly because the amount of steam makeup water needs to be dynamically adjusted according to the steam output load, while the amount of heat recovery water from the oil cooler is determined by the compressor's operating load and cooling demand. The two control logics are independent and lack a linkage mechanism, which can easily lead to supply and demand imbalance. When the amount of steam makeup water is less than the amount of heat recovery water, the oil cooling is insufficient, and the compressor is prone to overheating, resulting in unreliable operation, high failure rate, and instability. When the amount of steam makeup water is greater than the amount of heat recovery water, the water level in the steam generator will be too high due to the excessive amount of makeup water, triggering a water level fault alarm, which also makes it difficult for the heat pump unit to operate stably.

[0005] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a circulating steam heat pump unit to solve the problem of insufficient cooling in the prior art. By recovering the heat generated during the oil cooling process, the energy efficiency and stability of the unit can be improved.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A circulating steam heat pump unit includes a control device and a heat pump circulation mechanism, a preheating mechanism, and a steam generating mechanism, all electrically connected to the control device. The heat pump circulation mechanism includes a compressor, a second heat exchanger, and a condenser. The oil side of the second heat exchanger is connected to the oil inlet and oil outlet of the compressor, forming an oil circulation loop. The water side of the second heat exchanger is connected to the preheating mechanism to provide a heat source for preheating. The circulation outlet of the compressor is connected to the refrigerant side of the condenser. The water inlet of the condenser is connected to the output end of the preheating mechanism, and the water outlet of the condenser is connected to the steam generating end of the steam generating mechanism. The compressor is electrically connected to the control device.

[0008] In the aforementioned circulating steam heat pump unit, the heat pump circulation mechanism further includes an auxiliary circulation unit, an evaporator, and a first expansion valve. The circulation outlet of the compressor is connected to the refrigerant inlet of the condenser, the refrigerant outlet of the condenser is connected to the main inlet of the auxiliary circulation unit, the main outlet of the auxiliary circulation unit is connected to the input end of the evaporator through the first expansion valve, and the output end of the evaporator is connected to the circulation inlet of the compressor. The auxiliary inlet of the auxiliary circulation unit is connected to the connecting pipe between the first expansion valve and the evaporator, and the auxiliary outlet of the auxiliary circulation unit is connected to the economizer inlet of the compressor.

[0009] In the circulating steam heat pump unit, the auxiliary circulation unit includes a first heat exchanger and a second expansion valve; the main inlet of the first heat exchanger is connected to the refrigerant outlet of the condenser, and the main outlet of the first heat exchanger is connected to the input end of the evaporator through the first expansion valve; the auxiliary inlet of the first heat exchanger is connected to the connecting pipe between the first expansion valve and the evaporator through the second expansion valve, and the auxiliary outlet of the first heat exchanger is connected to the economizer inlet of the compressor.

[0010] In the circulating steam heat pump unit, the heat pump circulation mechanism further includes a second temperature sensor, a third temperature sensor, and a solenoid valve, which are electrically connected to the control device respectively. The second temperature sensor is installed on the connecting pipe between the oil outlet of the second heat exchanger and the oil inlet of the compressor. The third temperature sensor is installed on the connecting pipe between the oil outlet of the compressor and the oil inlet of the second heat exchanger. The oil outlet of the compressor is also connected to the connecting pipe between the oil outlet of the second heat exchanger and the oil inlet of the compressor through the solenoid valve.

[0011] In the circulating steam heat pump unit, the preheating mechanism includes a water storage tank, a first check valve, and a first electric valve, a second electric valve, a first water pump, a third electric valve, a fourth electric valve, and a first liquid level sensor, all electrically connected to the control device. The input end of the first electric valve is connected to the water inlet, the output end of the first electric valve is connected to the water-side inlet of the second heat exchanger, the water-side outlet of the second heat exchanger is connected to the input end of the water storage tank, the output end of the water storage tank is connected to the input end of the second electric valve, and the output end of the second electric valve is connected to the first drain outlet. The output end of the water storage tank is connected to the input end of the third electric valve via the first water pump and the first check valve, and the output end of the third electric valve is connected to the input end of the steam generating mechanism. The output end of the third electric valve is also connected to the input end of the fourth electric valve, and the output end of the fourth electric valve is connected to the second drain outlet. The first liquid level sensor is used to acquire the liquid level information in the water storage tank.

[0012] In the circulating steam heat pump unit, the steam generating mechanism includes a second check valve and a steam generator, a second water pump, a pressure sensor, a first temperature sensor, and a second liquid level sensor, all electrically connected to the control device. The output end of the third electric valve is connected to the water-side inlet of the condenser via the second water pump, and the water-side outlet of the condenser is connected to the input end of the steam generator. The pressure sensor and the first temperature sensor are installed at one output end of the steam generator, and the other output end of the steam generator is connected to the input end of the fourth electric valve via the second check valve. The second liquid level sensor is used to acquire the liquid level information within the steam generator.

[0013] The present invention also provides a control method for a circulating steam heat pump unit, the control method being implemented based on any of the circulating steam heat pump units described above, the circulating steam heat pump unit further including a second temperature sensor for acquiring the compressor oil inlet temperature; the control method includes: acquiring the real-time oil inlet temperature fed back by the second temperature sensor, and acquiring a preset oil inlet temperature control range, the oil inlet temperature control range including an lower limit value and an upper limit value; when the lower limit value ≤ the real-time oil inlet temperature ≤ the upper limit value, controlling the water-side water inlet flow of the second heat exchanger to remain unchanged; when the real-time oil inlet temperature > the upper limit value, controlling the water-side water inlet flow of the second heat exchanger to increase; when the real-time oil inlet temperature < the lower limit value, controlling the water-side water inlet flow of the second heat exchanger to decrease.

[0014] In the control method of the circulating steam heat pump unit, the preheating mechanism includes a water storage tank and a first liquid level sensor. The input end of the water storage tank is connected to the water-side outlet of the second heat exchanger, and the output end of the water storage tank is connected to the water-side input end of the condenser. The first liquid level sensor is used to acquire the liquid level information in the water storage tank. The control method further includes: acquiring the real-time water level of the water storage tank fed back by the first liquid level sensor, and acquiring a preset water level control range, wherein the water level control range includes a lower limit value and an upper limit value of the water level; when the lower limit value of the water level ≤ the real-time water level ≤ the upper limit value of the water level, the drainage volume of the water storage tank is kept constant; when the real-time water level > the upper limit value of the water level, the drainage volume of the water storage tank is increased; when the real-time water level < the lower limit value of the water level, the drainage volume of the water storage tank is decreased.

[0015] In the control method of the circulating steam heat pump unit, the steam generating mechanism includes a steam generator and a second liquid level sensor. The input end of the steam generator is connected to the water-side outlet of the condenser, and the output end of the steam generator is connected to the output end of the preheating mechanism. The second liquid level sensor is used to acquire liquid level information in the steam generator. The control method further includes: acquiring the real-time steam liquid level of the steam generator fed back by the second liquid level sensor, and acquiring a preset steam liquid level control range, the steam liquid level control range including a lower limit value and an upper limit value of the steam liquid level; when the lower limit value of the steam liquid level ≤ the real-time steam liquid level ≤ the upper limit value of the steam liquid level, the water-side water inlet of the condenser is kept constant; when the real-time steam liquid level > the upper limit value of the steam liquid level, the water-side water inlet of the condenser is increased; when the real-time steam liquid level < the lower limit value of the steam liquid level, the water-side water inlet of the condenser is decreased.

[0016] In the control method of the circulating steam heat pump unit, a pressure sensor is installed at one output end of the steam generator; the control method further includes: acquiring the real-time exhaust pressure fed back by the pressure sensor, and acquiring a preset exhaust pressure control range, wherein the exhaust control range includes a lower limit value and an upper limit value of the exhaust pressure; when the lower limit value of the exhaust pressure ≤ the real-time exhaust pressure ≤ the upper limit value of the exhaust pressure, the compressor is controlled to maintain its working state unchanged; when the real-time exhaust pressure > the upper limit value of the exhaust pressure, the compressor is controlled to unload; when the real-time exhaust pressure < the lower limit value of the exhaust pressure, the compressor is controlled to load.

[0017] Beneficial effects: This invention provides a circulating steam heat pump unit that effectively solves the technical pain point of insufficient compressor cooling in traditional units by constructing a linkage structure of oil circuit circulation and water-side heat exchange. It directly and precisely cools the compressor under high-temperature operating conditions, significantly reducing the risk of damage to the compressor and its components due to overheating and significantly improving the unit's operational reliability. At the same time, the heat generated during oil circuit cooling is efficiently recovered for steam preheating, avoiding the heat waste caused by traditional external cooling methods. This improves the unit's heating capacity and efficiency while reducing overall energy consumption. The electrical connection design of the control device and various mechanisms lays a solid structural foundation for subsequent precise control, ensuring a high degree of matching of parameters in the cooling, preheating, and steam production stages. This guarantees the coordinated and orderly operation of all units in the circulating steam heat pump unit and improves the stability of the unit during operation. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of the circulating steam heat pump unit provided by the present invention; Figure 2 A first logic flowchart of the control method provided by the present invention; Figure 3 A second logic flowchart of the control method provided by the present invention; Figure 4 The third logic flowchart of the control method provided by the present invention; Figure 5 The fourth logic flowchart of the control method provided by the present invention.

[0019] Key component symbols: 101-Compressor, 102-Second heat exchanger, 103-Condenser, 104-Evaporator, 105-First expansion valve, 106-First heat exchanger, 107-Second expansion valve, 108-Second temperature sensor, 109-Third temperature sensor, 110-Solenoid valve, 21-Water storage tank, 22-First check valve, 23-First electric valve, 24-Second electric valve, 25-First water pump, 26-Third electric valve, 27-Fourth electric valve, 28-First liquid level sensor, 31-Second check valve, 32-Steam generator, 33-Second water pump, 34-Pressure sensor, 35-First temperature sensor, 36-Second liquid level sensor. Detailed Implementation

[0020] This invention provides a circulating steam heat pump unit and its control method. To make the purpose, technical solution and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] In the description of this invention, it should be understood that the terms "installation" and "connection" should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] Please see Figure 1 This invention provides a circulating steam heat pump unit, including a control device and a heat pump circulation mechanism, a preheating mechanism, and a steam generating mechanism, all electrically connected to the control device. The heat pump circulation mechanism includes a compressor 101, a second heat exchanger 102, and a condenser 103. The oil side of the second heat exchanger 102 is connected to the oil inlet and oil outlet of the compressor 101, forming an oil circulation. The water side of the second heat exchanger 102 is connected to the preheating mechanism to provide a preheating heat source. The circulation outlet of the compressor 101 is connected to the refrigerant side of the condenser 103. The water inlet of the condenser 103 is connected to the output end of the preheating mechanism, and the water outlet of the condenser 103 is connected to the steam generating end of the steam generating mechanism. The compressor 101 is electrically connected to the control device.

[0023] The circulating steam heat pump unit disclosed in this invention effectively solves the technical pain point of insufficient cooling of the compressor 101 in traditional units by constructing a linkage structure of oil circuit circulation and water-side heat exchange. It directly and precisely cools the compressor 101 under high-temperature operating conditions, significantly reducing the risk of damage to the compressor 101 and its components due to overheating, and significantly improving the reliability of unit operation. At the same time, the heat generated during the oil circuit cooling process is efficiently recovered for steam preheating, avoiding the heat waste caused by traditional external cooling methods. This not only improves the heating capacity and heating efficiency of the unit, but also reduces the overall energy consumption. The electrical connection design of the control device and various mechanisms lays a solid structural foundation for subsequent precise control, ensuring a high degree of matching of parameters in each stage of cooling, preheating, and steam production. This ensures the coordinated and orderly operation of all mechanisms and units of the circulating steam heat pump unit, and improves the stability of the unit during operation.

[0024] In this embodiment, the second heat exchanger 102 in the heat pump circulation mechanism forms a bidirectional heat exchange channel between the oil circuit and the water side. Its oil side is connected to the oil circuit inlet and oil circuit outlet of the compressor 101 respectively, forming a closed oil circuit circulation, which is specifically used to cool the compressor 101. Its water side is connected to the preheating mechanism, which transfers the heat generated during the oil circuit cooling process to the preheating mechanism, providing a heat source for water preheating. The circulation outlet of compressor 101 is connected to the refrigerant side of condenser 103. The refrigerant releases heat in condenser 103. The water-side inlet of condenser 103 is connected to the output end of preheating mechanism, receiving preheated makeup water. The makeup water absorbs the heat released by the refrigerant on the water side of condenser 103, and its temperature rises. It is then transported to the steam generation end of steam generation mechanism through the water-side outlet of condenser 103, ultimately generating steam. After releasing heat in condenser 103, the steam flows back to the circulation inlet of compressor 101 along the refrigerant circulation loop, completing the heat release and circulation process of the refrigerant. The control device, as the control center of the entire unit, obtains the operating parameters of each mechanism in real time through electrical connection, including temperature, liquid level, pressure, etc., and sends control commands to compressor 101, various valves and other actuators to ensure the coordinated and orderly operation of the entire system. Furthermore, the heat pump circulation mechanism also includes an auxiliary circulation unit, an evaporator 104, and a first expansion valve 105. The circulation outlet of the compressor 101 is connected to the refrigerant inlet of the condenser 103, the refrigerant outlet of the condenser 103 is connected to the main inlet of the auxiliary circulation unit, the main outlet of the auxiliary circulation unit is connected to the input end of the evaporator 104 through the first expansion valve 105, and the output end of the evaporator 104 is connected to the circulation inlet of the compressor 101. The auxiliary inlet of the auxiliary circulation unit is connected to the connecting pipe between the first expansion valve 105 and the evaporator 104, and the auxiliary outlet of the auxiliary circulation unit is connected to the economizer inlet of the compressor 101.

[0025] In this embodiment, the working principle of the main circulation of the auxiliary circulation unit is as follows: the high-temperature and high-pressure refrigerant output from the circulation outlet of the compressor 101 enters the refrigerant inlet of the condenser 103. After releasing heat in the condenser 103, it flows out from the refrigerant outlet and enters the main inlet of the auxiliary circulation unit. After flowing out from the main outlet of the auxiliary circulation unit, it is throttled and depressurized through the first expansion valve 105, and then enters the input end of the evaporator 104. The refrigerant absorbs external heat in the evaporator 104 to complete evaporation, and then flows out from the output end of the evaporator 104 and flows back to the circulation inlet of the compressor 101, completing the heat release and heat absorption process of the main circulation of the refrigerant. The core function of the auxiliary circulation unit is to realize the cascade recovery and utilization of refrigerant energy, effectively reduce the operating load of compressor 101, and further improve the unit's energy efficiency. Specifically, the auxiliary inlet of the auxiliary circulation unit is connected to the connecting pipe between the first expansion valve 105 and the evaporator 104. The refrigerant in this section of the pipe is in a low-temperature state. After the low-temperature refrigerant enters the auxiliary circulation unit, it absorbs heat and rises in temperature. Then, it is transported to the energy-saving inlet of compressor 101 through the auxiliary outlet of the auxiliary circulation unit to supplement the energy for the operation of compressor 101, thereby reducing the power consumption of compressor 101.

[0026] In this embodiment, the main function of the evaporator 104 is to provide a low-temperature heat source for refrigerant evaporation, ensuring that the refrigerant can fully absorb heat and evaporate in the main circulation, thereby improving the thermodynamic efficiency of the refrigerant circulation. The refrigerant flow directions of the main and auxiliary circuits are coordinated with each other. The refrigerant in the main circuit undertakes the main heat release task, while the refrigerant in the auxiliary circuit further optimizes the energy-saving effect of the entire heat pump cycle through energy recovery, thereby improving the thermodynamic performance of the refrigerant circulation.

[0027] In this embodiment, the auxiliary circulation unit, evaporator 104 and first expansion valve 105 form a dual-circulation refrigerant system, which makes the refrigerant flow and heat transfer more balanced, avoids the problem of local overheating or insufficient heat exchange that may occur in a single circulation, extends the service life of the refrigerant circulation components, and improves the overall stability and reliability of the heat pump circulation mechanism.

[0028] Furthermore, the auxiliary circulation unit includes a first heat exchanger 106 and a second expansion valve 107; the main inlet of the first heat exchanger 106 is connected to the refrigerant outlet of the condenser 103, and the main outlet of the first heat exchanger 106 is connected to the input end of the evaporator 104 through the first expansion valve 105; the auxiliary inlet of the first heat exchanger 106 is connected to the connecting pipe between the first expansion valve 105 and the evaporator 104 through the second expansion valve 107, and the auxiliary outlet of the first heat exchanger 106 is connected to the economizer inlet of the compressor 101.

[0029] In this embodiment, the first heat exchanger 106 has a bidirectional heat exchange function. Its main circuit and auxiliary circuit are independent of each other and heat transfer is achieved through the wall. The main circuit is dedicated to receiving high-temperature refrigerant from the condenser 103. The high-temperature refrigerant enters the main circuit inlet of the first heat exchanger 106, releases heat and cools down in the main circuit, and then flows out from the main circuit outlet and enters the evaporator 104 through the first expansion valve 105. The auxiliary circuit delivers low-temperature refrigerant from between the first expansion valve 105 and the evaporator 104. The high-temperature main circuit refrigerant and the low-temperature auxiliary circuit refrigerant exchange heat in the first heat exchanger 106. The main circuit refrigerant is further cooled down, and the auxiliary circuit refrigerant is further heated up, realizing efficient energy transfer and cascade utilization. The second expansion valve 107 is connected to the connecting pipe between the auxiliary inlet of the first heat exchanger 106 and the first expansion valve 105 and evaporator 104. The low-temperature refrigerant in the connecting pipe flows through the second expansion valve 107 for throttling and regulation, and then enters the auxiliary inlet of the first heat exchanger 106. After absorbing heat and rising in temperature in the first heat exchanger 106, it flows out from the auxiliary outlet and connects to the inlet of the energy-saving device of the compressor 101. The core function of the second expansion valve 107 is to precisely regulate the flow rate and pressure of the refrigerant entering the auxiliary circuit of the first heat exchanger 106, ensuring that the temperature and pressure of the refrigerant in the auxiliary circuit strictly match the inlet requirements of the energy-saving device of the compressor 101, avoiding adverse effects on the operation of the compressor 101 due to fluctuations in refrigerant parameters, and further improving the energy efficiency and operational stability of the heat pump cycle mechanism.

[0030] Furthermore, the heat pump circulation mechanism also includes a second temperature sensor 108, a third temperature sensor 109, and a solenoid valve 110, which are electrically connected to the control device respectively. The second temperature sensor 108 is installed on the connecting pipe between the oil outlet of the second heat exchanger 102 and the oil inlet of the compressor 101. The third temperature sensor 109 is installed on the connecting pipe between the oil outlet of the compressor 101 and the oil inlet of the second heat exchanger 102. The oil outlet of the compressor 101 is also connected to the connecting pipe between the oil outlet of the second heat exchanger 102 and the oil inlet of the compressor 101 through the solenoid valve 110.

[0031] In this embodiment, the second temperature sensor 108 is installed on the connecting pipe between the oil outlet of the second heat exchanger 102 and the oil inlet of the compressor 101. It is specifically used to collect the oil inlet temperature of the compressor 101 in real time. The real-time oil inlet temperature data directly reflects the cooling effect of the oil circuit and provides a key basis for the control device to judge the cooling status. The third temperature sensor 109 is installed on the connecting pipe between the oil outlet of the compressor 101 and the oil inlet of the second heat exchanger 102. It is used to collect the oil outlet temperature of the compressor 101. The oil outlet temperature can directly reflect the heat intensity generated by the operation of the compressor 101, and assist the control device in making a comprehensive judgment on the oil circuit heat load. One end of the solenoid valve 110 is connected to the oil outlet of the compressor 101, and the other end is connected to the connecting pipe between the oil outlet of the second heat exchanger 102 and the oil inlet of the compressor 101, forming an oil bypass channel. Its core function is to adjust the amount of oil entering the second heat exchanger 102 through switching action, thereby dynamically adjusting the cooling intensity. Specifically, the control device receives monitoring data from two temperature sensors in real time. When the inlet oil temperature is too high, it is judged that the cooling is insufficient, and the solenoid valve 110 is closed, so that all the oil in the oil circuit flows through the second heat exchanger 102 for cooling. When the inlet oil temperature is too low, it is judged that the cooling is excessive, and the solenoid valve 110 is opened, so that some of the oil flows directly back to the inlet of the compressor 101 through the bypass channel, reducing the amount of oil participating in cooling, thereby reducing the cooling amount and ensuring that the oil temperature is stable within a reasonable range. Through the collaborative design of dual temperature sensors and solenoid valve 110, real-time and accurate monitoring of the oil circuit temperature of compressor 101 is achieved. When the oil temperature changes, it can quickly respond to oil temperature fluctuations, avoiding the impact of excessively high or low oil temperature on the operating performance of compressor 101, and further improving the reliability of unit operation. A stable oil temperature environment can effectively reduce the aging and wear of oil circuit components, reduce the risk of compressor 101 failure due to abnormal oil temperature, extend the overall service life of the unit, and optimize the operating efficiency of the oil circuit system, providing a guarantee for the efficient operation of the entire heat pump cycle.

[0032] Further, the preheating mechanism includes a water storage tank 21, a first check valve 22, and a first electric valve 23, a second electric valve 24, a first water pump 25, a third electric valve 26, a fourth electric valve 27, and a first liquid level sensor 28, all electrically connected to the control device. The input end of the first electric valve 23 is connected to the water inlet, the output end of the first electric valve 23 is connected to the water-side inlet of the second heat exchanger 102, the water-side outlet of the second heat exchanger 102 is connected to the input end of the water storage tank 21, and the output end of the water storage tank 21 is connected to the second electric valve 25. The input end of the second electric valve 24 is connected to the first drain outlet; the output end of the water storage tank 21 is connected to the input end of the third electric valve 26 via the first water pump 25 and the first check valve 22 connected in sequence; the output end of the third electric valve 26 is connected to the input end of the steam generating mechanism; the output end of the third electric valve 26 is also connected to the input end of the fourth electric valve 27; the output end of the fourth electric valve 27 is connected to the second drain outlet; the first liquid level sensor 28 is used to obtain the liquid level information in the water storage tank 21.

[0033] In this embodiment, the water inlet adjustment of the preheating mechanism is achieved by the first electric valve 23. The input end of the first electric valve 23 is connected to the external water inlet, and its output end is connected to the water-side inlet of the second heat exchanger 102. The control device adjusts the opening of the first electric valve 23 to precisely control the amount of water entering the second heat exchanger 102, ensuring that the water inlet flow rate matches the cooling heat. In the preheating and water storage process of the preheating mechanism, external water enters the water side of the second heat exchanger 102 through the first electric valve 23. After absorbing the heat generated by the oil cooling to complete the preheating, it is transported to the water storage tank 21 for storage. The water storage tank 21 serves as a buffer device to provide a stable source of preheating water for steam production and avoid the impact of water supply fluctuations on steam production. The drainage regulation of the preheating mechanism is completed by the second electric valve 24. The second electric valve 24 is connected between the output end of the water storage tank 21 and the first drain outlet, and is used to drain excess water or sediment in the water storage tank 21. The first liquid level sensor 28 is installed in the water storage tank 21 to collect liquid level information in real time and feed it back to the control device, providing data support for drainage regulation. In the water supply and diversion process of the preheating mechanism, the output end of the water storage tank 21 is connected in sequence to the first water pump 25 and the first check valve 22, and then connected to the input end of the third electric valve 26. The first water pump 25 provides power for water replenishment and delivery, and the first check valve 22 effectively prevents water backflow and ensures stable pipeline pressure. The output end of the third electric valve 26 is divided into two paths. One path is connected to the input end of the steam generator to directly supply water for steam production, and the other path is connected to the input end of the fourth electric valve 27. The output end of the fourth electric valve 27 is connected to the second drain outlet to discharge excess water or to achieve pipeline cleaning function.

[0034] In this embodiment, the preheating mechanism achieves controllable preheating and stable supply of water through a complete water inlet, preheating, storage, diversion, and drainage system. The preheating effect of the second heat exchanger 102 effectively increases the water supply temperature, reducing the heating energy consumption of the steam generating mechanism. The coordinated operation of the first electric valve 23 and the first water pump 25 allows the water supply volume to be precisely adjusted according to actual needs, perfectly matching the dynamic requirements of steam production. The real-time monitoring of the first liquid level sensor 28 and the drainage adjustment of the second electric valve 24 are linked to effectively prevent the water level in the storage tank 21 from being too high. This design significantly improves the operational stability of the preheating mechanism, preventing water waste or low liquid levels that could affect the continuity of steam production. The first check valve 22 prevents water backflow and avoids abnormal pipeline pressure. The diversion drainage design of the fourth electric valve 27 facilitates pipeline cleaning and impurity removal, reducing the risk of preheating mechanism failure. The overall structural design enhances the matching between preheating and steam production. The diversion design allows the water supply to be dynamically adjusted according to the needs of the steam generating mechanism, fundamentally solving the technical problem of mismatch between heat recovery water and steam supply in traditional units.

[0035] Furthermore, the steam generating mechanism includes a second check valve 31 and a steam generator 32, a second water pump 33, a pressure sensor 34, a first temperature sensor 35, and a second liquid level sensor 36, all electrically connected to the control device. The output end of the third electric valve 26 is connected to the water-side inlet of the condenser 103 via the second water pump 33, and the water-side outlet of the condenser 103 is connected to the input end of the steam generator 32. The pressure sensor 34 and the first temperature sensor 35 are installed at one output end of the steam generator 32, and the other output end of the steam generator 32 is connected to the input end of the fourth electric valve 27 via the second check valve 31. The second liquid level sensor 36 is used to obtain liquid level information within the steam generator 32.

[0036] In this embodiment, in the water supply heating and conveying process of the steam generator, the water supply at the output end of the third electric valve 26 is pressurized by the second water pump 33 and then conveyed to the water-side inlet of the condenser 103. The water supply is fully heated by the high-temperature refrigerant on the refrigerant side of the condenser 103. After the water supply is heated to a high temperature, it is conveyed from the water-side outlet of the condenser 103 to the input end of the steam generator 32 to provide a high-temperature water source for steam generation. In the steam generation and output stage of the steam generating mechanism, after high-temperature makeup water enters the steam generator 32, it completes the vaporization reaction to generate steam in the steam generator 32. The steam is discharged from the output end on one side of the steam generator 32. The output end is equipped with a pressure sensor 34 and a first temperature sensor 35 to monitor the pressure and temperature parameters of the steam in real time to ensure that the steam quality meets the usage requirements. In the liquid level monitoring and backflow protection of the steam generator, the second liquid level sensor 36 is installed inside the steam generator 32 to collect the liquid level information of the steam generator 32 in real time, providing data support for liquid level regulation; the output end of the other side of the steam generator 32 is connected to the input end of the fourth electric valve 27 through the second check valve 31. When the liquid level of the steam generator 32 is too high, the excess water can flow back to the drainage system through this path, effectively avoiding failure caused by excessive liquid level. The second check valve 31 can prevent steam or water backflow and ensure pipeline safety.

[0037] In this embodiment, the linkage design of the condenser 103 and the steam generator 32 enables the water to undergo two heating processes—preheating and heating by the condenser 103—significantly improving steam generation efficiency. The pressurization effect of the second water pump 33 ensures stable water delivery, avoids interruption of steam generation, and guarantees the continuity of steam supply. The real-time monitoring function of the pressure sensor 34 and the first temperature sensor 35 provides the control device with accurate steam pressure and temperature data, facilitating subsequent dynamic adjustment of core components such as the compressor 101 to ensure that steam parameters strictly meet usage requirements. The liquid level monitoring of the second liquid level sensor 36 and the backflow protection of the second check valve 31 work together to effectively prevent the steam generator 32 from malfunctioning due to excessively high liquid levels or dry burning due to excessively low liquid levels, greatly improving the reliability and safety of the steam generation mechanism. The overall structural design enhances system synergy, with the input end of the steam generation mechanism and the output end of the preheating mechanism closely linked. The monitoring data from the output end is fed back to the control device in real time, achieving precise parameter matching for each stage of preheating, heating, and steam generation, comprehensively ensuring the stable and efficient operation of the entire system.

[0038] Please see Figure 2 The present invention also provides a control method for a circulating steam heat pump unit, the control method being implemented based on any of the circulating steam heat pump units described above, the circulating steam heat pump unit further comprising a second temperature sensor 108 for acquiring the oil inlet temperature of the compressor 101; the control method includes: 101. Obtain the real-time oil inlet temperature fed back by the second temperature sensor 108, and obtain the preset oil inlet temperature control range, wherein the oil inlet temperature control range includes the lower limit of the oil inlet temperature and the upper limit of the oil inlet temperature. In this embodiment, the oil inlet temperature control range is determined through experimental testing and simulation calculation based on the rated operating oil temperature of compressor 101, the cooling efficiency of the second heat exchanger 102, and the overall operating parameters of the unit. It is the optimal range to ensure the safe and efficient operation of compressor 101.

[0039] 102. When the lower limit of the oil inlet temperature is less than or equal to the real-time oil inlet temperature and the upper limit of the oil inlet temperature, the water inlet flow rate of the second heat exchanger 102 is kept constant. In this embodiment, when the real-time oil inlet temperature is between the lower limit of the oil inlet temperature and the upper limit of the oil inlet temperature, it indicates that the oil circuit cooling effect meets the preset requirements, and there is no need to adjust the water inlet flow. The control device issues a command to keep the water inlet flow of the second heat exchanger 102 in its current state.

[0040] 103. When the real-time oil inlet temperature is greater than the upper limit of the oil inlet temperature, the water inlet flow rate of the second heat exchanger 102 is increased. In this embodiment, when the real-time oil inlet temperature is higher than the upper limit of the oil inlet temperature, it indicates that the oil circuit cooling is insufficient and the cooling intensity needs to be increased. The control device issues a command to increase the water inlet flow of the second heat exchanger 102. By increasing the water-side heat exchange area or water flow velocity, the heat absorption efficiency is improved, thereby reducing the oil temperature.

[0041] 104. When the real-time oil inlet temperature is less than the lower limit of the oil inlet temperature, the water inlet flow rate of the second heat exchanger 102 is reduced. In this embodiment, when the real-time oil inlet temperature is lower than the lower limit of the oil inlet temperature, it indicates that the oil circuit is overcooled, which may cause heat waste or affect the preheating effect. The control device issues a command to reduce the water inlet volume of the second heat exchanger 102, reduce the cooling intensity, and allow the oil temperature to rise back to a reasonable range.

[0042] In this embodiment, the water inlet flow rate of the second heat exchanger 102 is adjusted by the opening degree of the first electric valve 23. Increasing the opening degree of the first electric valve 23 increases the water inlet flow rate, while decreasing it decreases the water inlet flow rate. This embodiment uses the oil inlet temperature as the core control indicator to construct a precise closed-loop control system for oil circuit cooling, ensuring that the oil temperature of the compressor 101 remains stable within the optimal operating range. This completely solves the technical problems of insufficient or excessive cooling in traditional units, significantly improving the operational reliability of the compressor 101. The dynamic adjustment of the water inlet flow rate ensures a high degree of match between the heat exchange efficiency of the second heat exchanger 102 and the oil temperature requirement. When the oil temperature is high, the water intake is increased to fully absorb the cooling heat for preheating and replenishment. When the oil temperature is low, the water intake is reduced to avoid excessive cold water leading to a decrease in preheating effect, thus maximizing the heat recovery and utilization rate. Precise cooling regulation avoids ineffective water consumption and heat waste. At the same time, a stable oil temperature environment significantly improves the operating efficiency of compressor 101, further reducing the overall energy consumption of the unit. The entire control process requires no manual intervention. The control device automatically completes the adjustment based on the data collected by the sensors, reducing human error and greatly improving the practicality and convenience of the unit, thus promoting the automation level of the unit's operation.

[0043] Further, please refer to Figure 1 and Figure 3The preheating mechanism includes a water storage tank 21 and a first liquid level sensor 28. The input end of the water storage tank 21 is connected to the water-side outlet of the second heat exchanger 102, and the output end of the water storage tank 21 is connected to the water-side input end of the condenser 103. The first liquid level sensor 28 is used to acquire liquid level information in the water storage tank 21. The control method further includes: 201. Obtain the real-time water level of the water tank 21 fed back by the first liquid level sensor 28, and obtain a preset water level control range, wherein the water level control range includes a lower limit value and an upper limit value of the water level. In this embodiment, the setting of the water storage level control range is determined by comprehensive calculation based on the capacity of the water storage tank 21, the water replenishment requirements of steam production, and the operating parameters of the preheating mechanism. It is a reasonable range to ensure a stable supply of water replenishment.

[0044] 202. When the lower limit of the water storage level is less than or equal to the real-time water storage level and the upper limit of the water storage level, the drainage volume of the water storage tank 21 is kept constant. 203. When the real-time water level is greater than the upper limit of the water level, the drainage volume of the water storage tank 21 is increased. 204. When the real-time water level is less than the lower limit of the water level, the drainage of the water tank 21 is reduced. In this embodiment, when the real-time water level is between the lower and upper limits of the water level, it indicates that the water level in the water tank 21 can meet the water replenishment requirements for steam production, and there is no need to adjust the drainage volume. The control device issues a command to keep the drainage volume of the water tank 21 at its current state. When the real-time water level is higher than the upper limit of the water level, it indicates that there is too much water in the water tank 21, which may lead to overflow waste or affect the stability of the water temperature in the tank. The control device issues a command to increase the drainage volume of the water tank 21. By adjusting the opening of the second electric valve 24, the excess water is quickly discharged, and the water level returns to a reasonable range. When the real-time water level is lower than the lower limit of the water level, it indicates that there is insufficient water in the water tank 21, which may lead to an interruption of water replenishment for steam production. The control device issues a command to reduce the drainage volume of the water tank 21. If necessary, the second electric valve 24 can be closed to retain the water in the tank and ensure the continuity of water replenishment supply. In this embodiment, by dynamically adjusting the drainage volume, the water level in the water storage tank 21 is effectively maintained, preventing overflow or water shortage. This ensures a continuous and stable supply of preheating water to the steam generating mechanism, guaranteeing the continuity and stability of steam production. A stable water level prevents fluctuations in water temperature caused by drastic changes in water volume, ensuring a stable preheating water temperature and providing strong support for the efficient operation of the steam generator 32. This method avoids water waste due to excessively high water levels and reduces unit shutdowns due to water shortages, significantly improving the unit's water resource utilization and operating efficiency. By controlling the water level, the synergy between the preheating mechanism and the steam generating mechanism is strengthened, ensuring that the water supply flow of the preheating mechanism always matches the water replenishment demand of the steam generating mechanism. This further solves the problem of mismatch between water replenishment and steam demand in traditional units, promoting the improvement of the overall system operating efficiency.

[0045] Further, please refer to Figure 1 and Figure 4 The steam generating mechanism includes a steam generator 32 and a second liquid level sensor 36. The input end of the steam generator 32 is connected to the water-side outlet of the condenser 103, and the output end of the steam generator 32 is connected to the output end of the preheating mechanism. The second liquid level sensor 36 is used to acquire liquid level information within the steam generator 32. The control method further includes: 301. Obtain the real-time steam level of the steam generator 32 fed back by the second liquid level sensor 36, and obtain a preset steam level control range, wherein the steam level control range includes a lower limit value of the steam level and an upper limit value of the steam level. In this embodiment, the setting of the steam level control range is determined through scientific calculation based on the rated capacity of the steam generator 32, the steam generation efficiency, and the safety operation requirements. It is the optimal range to ensure the safe and stable generation of steam.

[0046] 302. When the lower limit of the steam level is less than or equal to the real-time steam level and the upper limit of the steam level, the water inlet flow rate of the condenser 103 is kept constant. 303. When the real-time steam level is greater than the upper limit of the steam level, the water inlet flow rate of the condenser 103 is increased. 304. When the real-time steam level is less than the lower limit of the steam level, the water inlet flow of the condenser 103 is reduced. In this embodiment, when the real-time steam level is between the lower and upper limits of the steam level, it indicates that the level of the steam generator 32 meets the requirements for steam production, and there is no need to adjust the water inlet flow. The control device issues a command to maintain the current water inlet flow of the condenser 103. When the real-time steam level is higher than the upper limit of the steam level, it indicates that there is too much water in the steam generator 32, which may lead to increased steam humidity or a level alarm. The control device issues a command to increase the water inlet flow of the condenser 103. By increasing the water flow rate, the heating and vaporization efficiency of the water is improved, water accumulation is reduced, and the level drops to a reasonable range. When the real-time steam level is lower than the lower limit of the steam level, it indicates that there is insufficient water in the steam generator 32, which may lead to interruption of steam generation or dry burning of the equipment. The control device issues a command to reduce the water inlet flow of the condenser 103 to avoid excessive water consumption and allow the level to rise back to a reasonable range.

[0047] In this embodiment, by dynamically adjusting the water inlet flow rate, the liquid level in the steam generator 32 is kept stable within a reasonable range, effectively avoiding steam quality degradation or fault alarms caused by excessively high liquid levels, as well as the risk of dry burning caused by excessively low liquid levels, significantly improving the reliability and safety of the steam generating mechanism. The stable liquid level ensures that the vaporization space and water volume within the steam generator 32 are matched, making the steam generation process more complete, the steam humidity and pressure more stable, and significantly improving the steam quality. At the same time, the precise adjustment of the water inlet flow rate avoids the impact of too much or too little water on vaporization efficiency, further improving the steam generation efficiency. This control method strengthens the system's coordinated adjustment capability, making the liquid level in the steam generator 32 and the water inlet flow rate on the water side of the condenser 103 closely linked, making the operation of the preheating mechanism, the heat pump circulation mechanism, and the steam generating mechanism more coordinated, comprehensively improving the overall operational stability and energy efficiency of the unit. The stable liquid level environment can reduce the wear and corrosion of the components inside the steam generator 32, extend the service life of the steam generator 32, reduce the unit's maintenance costs, and improve the unit's economy and practicality.

[0048] Further, please refer to Figure 1 and Figure 5 A pressure sensor 34 is provided at one output end of the steam generator 32; the control method further includes: 401. Obtain the real-time exhaust pressure fed back by the pressure sensor 34, and obtain a preset exhaust pressure control range, wherein the exhaust control range includes a lower limit value and an upper limit value of the exhaust pressure. In this embodiment, the setting of the exhaust control range is determined by comprehensive calculation based on the pressure requirements of the steam usage scenario, the rated power of the compressor 101, and the overall operating parameters of the unit. It is the optimal range to ensure the steam usage effect and equipment safety.

[0049] 402. When the lower limit of the exhaust pressure is less than or equal to the real-time exhaust pressure and the upper limit of the exhaust pressure, the compressor 101 is controlled to remain in a constant working state. 403. When the real-time exhaust pressure is greater than the upper limit of the exhaust pressure, control the compressor 101 to unload; 404. When the real-time exhaust pressure is less than the lower limit of the exhaust pressure, control the compressor 101 to load; In this embodiment, when the real-time exhaust pressure is between the lower and upper limits of the exhaust pressure, it indicates that the steam pressure meets the usage requirements. No adjustment to the compressor 101's operating state is needed, and the control device issues a command to keep the compressor 101 in its current operating state. When the real-time exhaust pressure is higher than the upper limit, it indicates that the steam pressure is too high, which may lead to equipment overpressure or safety risks. The control device issues a command to unload the compressor 101, reducing its operating power and refrigerant circulation, thereby reducing the heat release from the condenser 103, slowing down the steam generation rate, and gradually lowering the pressure to a reasonable range. When the real-time exhaust pressure is lower than the lower limit, it indicates that the steam pressure is insufficient and cannot meet the usage requirements. The control device issues a command to load the compressor 101, increasing its operating power and refrigerant circulation, thereby increasing the heat release from the condenser 103, accelerating the steam generation rate, and causing the pressure to rise back to a reasonable range.

[0050] In this embodiment, a precise and stable steam pressure control system is constructed with exhaust pressure as the core indicator, ensuring that the steam pressure always meets the usage requirements. This effectively solves the problem of large steam pressure fluctuations in traditional units and significantly improves the stability and reliability of steam supply. By dynamically adjusting the operating status of compressor 101, overpressure damage or safety accidents caused by excessively high steam pressure are avoided, while excessively low pressure is prevented from affecting the performance, providing a solid safety guarantee for unit operation and personnel operation. The loading and unloading adjustment of compressor 101 ensures that the operating power of compressor 101 is highly matched with the steam demand, avoiding long-term full-load operation or inefficient operation of compressor 101, which reduces the energy consumption of compressor 101 and extends its service life. This control method has good flexibility and can flexibly adjust the preset pressure range according to the pressure requirements of different usage scenarios, making the unit suitable for various steam pressure requirements, greatly expanding the application range of the unit, and improving the market applicability and competitiveness of the unit.

[0051] It is understood that those skilled in the art can make equivalent substitutions or changes to the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A circulating steam heat pump unit, characterized in that, The system includes a control device and a heat pump circulation mechanism, a preheating mechanism, and a steam generating mechanism, all electrically connected to the control device. The heat pump circulation mechanism includes a compressor, a second heat exchanger, and a condenser. The oil side of the second heat exchanger is connected to the oil inlet and oil outlet of the compressor, forming an oil circulation loop. The water side of the second heat exchanger is connected to the preheating mechanism to provide a heat source for preheating. The circulation outlet of the compressor is connected to the refrigerant side of the condenser. The water inlet of the condenser is connected to the output end of the preheating mechanism, and the water outlet of the condenser is connected to the steam generating end of the steam generating mechanism. The compressor is electrically connected to the control device.

2. The circulating steam heat pump unit according to claim 1, characterized in that, The heat pump circulation mechanism further includes an auxiliary circulation unit, an evaporator, and a first expansion valve. The circulation outlet of the compressor is connected to the refrigerant inlet of the condenser, the refrigerant outlet of the condenser is connected to the main inlet of the auxiliary circulation unit, the main outlet of the auxiliary circulation unit is connected to the input end of the evaporator through the first expansion valve, and the output end of the evaporator is connected to the circulation inlet of the compressor. The auxiliary inlet of the auxiliary circulation unit is connected to the connecting pipe between the first expansion valve and the evaporator, and the auxiliary outlet of the auxiliary circulation unit is connected to the economizer inlet of the compressor.

3. A circulating steam heat pump unit according to claim 2, characterized in that, The auxiliary circulation unit includes a first heat exchanger and a second expansion valve; the main inlet of the first heat exchanger is connected to the refrigerant outlet of the condenser, and the main outlet of the first heat exchanger is connected to the input end of the evaporator through the first expansion valve; the auxiliary inlet of the first heat exchanger is connected to the connecting pipe between the first expansion valve and the evaporator through the second expansion valve, and the auxiliary outlet of the first heat exchanger is connected to the economizer inlet of the compressor.

4. A circulating steam heat pump unit according to claim 1, characterized in that, The heat pump circulation mechanism further includes a second temperature sensor, a third temperature sensor, and a solenoid valve, which are electrically connected to the control device. The second temperature sensor is installed on the connecting pipe between the oil outlet of the second heat exchanger and the oil inlet of the compressor. The third temperature sensor is installed on the connecting pipe between the oil outlet of the compressor and the oil inlet of the second heat exchanger. The oil outlet of the compressor is also connected to the connecting pipe between the oil outlet of the second heat exchanger and the oil inlet of the compressor through the solenoid valve.

5. A circulating steam heat pump unit according to claim 1, characterized in that, The preheating mechanism includes a water storage tank, a first check valve, and a first electric valve, a second electric valve, a first water pump, a third electric valve, a fourth electric valve, and a first liquid level sensor, all electrically connected to the control device. The input end of the first electric valve is connected to the water inlet, the output end of the first electric valve is connected to the water-side inlet of the second heat exchanger, the water-side outlet of the second heat exchanger is connected to the input end of the water storage tank, the output end of the water storage tank is connected to the input end of the second electric valve, and the output end of the second electric valve is connected to the first drain outlet. The output end of the water storage tank is connected to the input end of the third electric valve via the first water pump and the first check valve, and the output end of the third electric valve is connected to the input end of the steam generating mechanism. The output end of the third electric valve is also connected to the input end of the fourth electric valve, and the output end of the fourth electric valve is connected to the second drain outlet. The first liquid level sensor is used to acquire the liquid level information in the water storage tank.

6. A circulating steam heat pump unit according to claim 5, characterized in that, The steam generating mechanism includes a second check valve and a steam generator, a second water pump, a pressure sensor, a first temperature sensor, and a second liquid level sensor, all electrically connected to the control device. The output end of the third electric valve is connected to the water-side inlet of the condenser via the second water pump, and the water-side outlet of the condenser is connected to the input end of the steam generator. The pressure sensor and the first temperature sensor are installed at one output end of the steam generator, and the other output end of the steam generator is connected to the input end of the fourth electric valve via the second check valve. The second liquid level sensor is used to acquire the liquid level information within the steam generator.

7. A control method for a circulating steam heat pump unit, characterized in that, The control method is implemented based on the circulating steam heat pump unit as described in any one of claims 1-6, wherein the circulating steam heat pump unit further includes a second temperature sensor for acquiring the compressor oil inlet temperature; the control method includes: The real-time oil inlet temperature fed back by the second temperature sensor is obtained, and a preset oil inlet temperature control range is obtained, wherein the oil inlet temperature control range includes an lower limit value and an upper limit value of the oil inlet temperature. When the lower limit of the oil inlet temperature is less than or equal to the real-time oil inlet temperature and the upper limit of the oil inlet temperature, the water inlet flow rate of the second heat exchanger is kept constant. When the real-time oil inlet temperature is greater than the upper limit of the oil inlet temperature, the water inlet flow rate of the second heat exchanger is increased. When the real-time oil inlet temperature is less than the lower limit of the oil inlet temperature, the water inlet flow rate of the second heat exchanger is reduced.

8. The control method for a circulating steam heat pump unit according to claim 7, characterized in that, The preheating mechanism includes a water storage tank and a first liquid level sensor. The input end of the water storage tank is connected to the water-side outlet of the second heat exchanger, and the output end of the water storage tank is connected to the water-side input end of the condenser. The first liquid level sensor is used to acquire liquid level information in the water storage tank; the control method further includes: The real-time water level of the storage tank is obtained from the feedback of the first liquid level sensor, and a preset water level control range is obtained, wherein the water level control range includes a lower limit value and an upper limit value of the water level. When the lower limit of the water storage level is less than or equal to the real-time water storage level and the upper limit of the water storage level, the drainage volume of the water storage tank is kept constant. When the real-time water level exceeds the upper limit of the water level, the drainage volume of the water tank is increased. When the real-time water level is less than the lower limit of the water level, the drainage of the water tank is reduced.

9. The control method for a circulating steam heat pump unit according to claim 7, characterized in that, The steam generating mechanism includes a steam generator and a second liquid level sensor. The input end of the steam generator is connected to the water-side outlet of the condenser, and the output end of the steam generator is connected to the output end of the preheating mechanism. The second liquid level sensor is used to acquire liquid level information within the steam generator. The control method further includes: The real-time steam level of the steam generator is obtained from the feedback of the second level sensor, and a preset steam level control range is obtained, which includes a lower limit value and an upper limit value of the steam level. When the lower limit of the steam level is less than or equal to the real-time steam level and the upper limit of the steam level, the water inlet flow rate of the condenser is kept constant. When the real-time steam level is greater than the upper limit of the steam level, the water inlet flow rate of the condenser is increased. When the real-time steam level is less than the lower limit of the steam level, the water inlet flow rate of the condenser is reduced.

10. The control method for a circulating steam heat pump unit according to claim 9, characterized in that, A pressure sensor is installed at one output terminal of the steam generator; the control method further includes: The real-time exhaust pressure fed back by the pressure sensor is obtained, and a preset exhaust pressure control range is obtained, wherein the exhaust pressure control range includes a lower limit value and an upper limit value of the exhaust pressure. When the lower limit of the exhaust pressure is less than or equal to the real-time exhaust pressure and the upper limit of the exhaust pressure, the compressor is controlled to remain in a constant working state. When the real-time exhaust pressure exceeds the upper limit of the exhaust pressure, the compressor is controlled to unload. When the real-time exhaust pressure is less than the lower limit of the exhaust pressure, the compressor is controlled to load.

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