Dual-working-condition heat pump system integrated with negative pressure phase change cycle and refrigeration and heating method thereof

Abstract

The application discloses a kind of integrated negative pressure phase change cycle dual working condition heat pump system and its refrigeration, heating method, system includes heat pump system, negative pressure circulation system, and for both heat exchange first heat exchanger and second heat exchanger;Heat pump system further includes compressor, four-way valve, condenser, expansion valve and regulating valve, with first heat exchanger and second heat exchanger jointly constitute heat pump circuit;Negative pressure circulation system further includes vacuum pump, circulating pump, water tank and load interface, with first heat exchanger and second heat exchanger jointly constitute negative pressure circulation loop, vacuum pump is established at load interface negative pressure environment to reduce the boiling point of circulating medium.It is in refrigeration mode, first heat exchanger deeply cools circulating medium, and second heat exchanger is precisely reheated temperature control using compressor exhaust waste heat;In heating mode, refrigerant is heated circulating medium by two-stage heat release.This application realizes low-temperature efficient phase change heat transfer and high-precision wide temperature range temperature control, and heat transfer efficiency and system comprehensive energy efficiency are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of heat pump systems that combine heating and cooling, and in particular to a dual-condition heat pump system integrating a negative pressure phase change cycle and its cooling and heating methods. Background Technology

[0002] Traditional single-phase liquid cooling solutions, when faced with ever-increasing heat loads, can only meet heat dissipation demands by increasing the liquid circulation volume. This directly leads to a significant increase in system pumping power consumption, larger pipe sizes, and soaring operating costs. More importantly, single-phase liquid cooling relies on the sensible heat rise of the cooling medium to remove heat, and its heat transfer coefficient is limited, making it difficult to achieve high-energy-density heat transfer. This has gradually become a bottleneck restricting further improvements in equipment performance.

[0003] To address the aforementioned issues, phase change heat dissipation technology has attracted attention due to its ability to utilize the large amount of latent heat released or absorbed during the phase change of the working fluid. The heat transfer coefficient of phase change heat transfer is typically several times, or even an order of magnitude, higher than that of single-phase liquid cooling, enabling higher energy transfer density without significantly increasing the working fluid flow rate. However, conventional phase change heat dissipation systems usually operate under atmospheric or positive pressure environments with relatively high boiling points of the working fluid. This makes it difficult to achieve phase change heat absorption at low temperatures, limiting its application in precision temperature control scenarios. Furthermore, the generated high-temperature steam places stringent requirements on the system's sealing and safety. In addition, while existing heat pump systems can switch between cooling and heating functions, the transition between these modes often requires complex piping switching or additional auxiliary heating devices, resulting in low system integration. Moreover, in cooling mode, the large amount of heat carried by the compressor exhaust is usually directly released into the environment without effective utilization, leading to energy waste. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art, such as low heat transfer efficiency of single-phase liquid cooling, high pumping power consumption, high boiling point of atmospheric pressure phase change system making it difficult to achieve low-temperature phase change and safety risks of high-temperature steam, as well as low energy utilization and insufficient temperature control accuracy of traditional heat pump system when switching between cooling and heating. The present invention provides a dual-condition heat pump system with integrated negative pressure phase change cycle and its cooling and heating methods. It can use the negative pressure environment to reduce the boiling point of the circulating medium to achieve low-temperature and high-efficiency phase change heat transfer. It achieves flexible switching between cooling and heating conditions through a heat pump system with a four-way valve. It adopts a stepped temperature control strategy that combines deep cooling of the first heat exchanger with waste heat reheating of the second heat exchanger, which significantly improves heat transfer efficiency, temperature control accuracy and overall system energy efficiency.

[0005] To solve the above-mentioned technical problems, the present invention provides a dual-condition heat pump system with integrated negative pressure phase change cycle, including a heat pump system, a negative pressure cycle system, and a first heat exchanger and a second heat exchanger for heat exchange between the heat pump system and the negative pressure cycle system. Both the first heat exchanger and the second heat exchanger have a refrigerant side connected to the heat pump system and a circulating medium side connected to the negative pressure circulation system. The heat pump system also includes a compressor, a four-way valve, a condenser, an expansion valve, and a regulating valve. The compressor's discharge port is connected to the refrigerant-side inlet of the second heat exchanger and to the inlet of the regulating valve. The refrigerant-side outlet of the second heat exchanger merges with the outlet of the regulating valve and is connected to the first port of the four-way valve. The second port of the four-way valve is connected to one end of the condenser, the other end of the condenser is connected to the inlet of the expansion valve, the outlet of the expansion valve is connected to the refrigerant-side inlet of the first heat exchanger, the refrigerant-side outlet of the first heat exchanger is connected to the third port of the four-way valve, and the fourth port of the four-way valve is connected to the compressor's suction port. The four-way valve has both cooling and heating flow directions: in the cooling direction, the first port is connected to the second port, and the third port is connected to the fourth port; in the heating direction, the first port is connected to the third port, and the second port is connected to the fourth port. The negative pressure circulation system includes a vacuum pump, a circulation pump, a water tank, and a load interface for connecting the terminal load; the vacuum pump is connected to the load interface to establish a negative pressure environment at the load interface; the outlet of the circulation pump is connected to the circulation medium side inlet of the first heat exchanger and the circulation medium side inlet of the second heat exchanger, respectively.

[0006] In one embodiment of the present invention, the negative pressure circulation system further includes: The first temperature detection device is installed at the outlet of the circulating medium side of the first heat exchanger and is used to detect the temperature of the circulating medium after flowing through the first heat exchanger. The second temperature detection device is installed at the outlet of the second heat exchanger on the circulating medium side and is used to detect the temperature of the circulating medium after flowing through the second heat exchanger. The third temperature detection device is located at the load interface and is used to detect the temperature of the circulating medium delivered to the end load. A pressure detection device is installed at the load interface to detect the pressure at the load interface.

[0007] In one embodiment of the present invention, the pressure value P of the negative pressure environment established by the vacuum pump at the load interface is set according to the target temperature T detected by the third temperature detection device according to the following relationship: P=A×T 4 -B×T 3 +C×T 2 -D×T+E; When the circulating medium is water, A=0.0000012136, B=0.0001043992, C=0.0108137083, D=0.2908714719, E=5.3000714286.

[0008] In one embodiment of the present invention, the opening degree of the expansion valve is adjusted according to the temperature detected by the first temperature detection device: when the temperature detected by the first temperature detection device is higher than the first preset target temperature range, the opening degree of the expansion valve is increased; when the temperature detected by the first temperature detection device is lower than the first preset target temperature range, the opening degree of the expansion valve is decreased. The opening of the regulating valve is adjusted according to the temperature detected by the second temperature detection device: when the temperature detected by the second temperature detection device is higher than the second preset target temperature, the opening of the regulating valve is increased to reduce the refrigerant flow through the refrigerant side of the second heat exchanger; when the temperature detected by the second temperature detection device is lower than the second preset target temperature, the opening of the regulating valve is decreased to increase the refrigerant flow through the refrigerant side of the second heat exchanger.

[0009] In one embodiment of the present invention, the negative pressure circulation system further includes a heater, which is connected in series in the pipeline between the circulation medium side outlet of the second heat exchanger and the load interface; In heating mode, the heater is turned on to further heat the circulating medium.

[0010] In one embodiment of the present invention, the negative pressure circulation system further includes a fourth temperature detection device, which is disposed after the heater and is used to detect the temperature of the circulating medium after being heated by the heater, thereby realizing the control of the heater.

[0011] In one embodiment of the present invention, the negative pressure circulation system further includes an ejector pump, which is associated with the vacuum pump. The power inlet of the ejector pump is connected to the outlet of the circulation pump, and is used to receive part of the circulating medium discharged by the circulation pump as a power source to drive the vacuum pump to work.

[0012] To address the aforementioned technical problems, this invention provides a cooling and heating method for a dual-condition heat pump system with an integrated negative pressure phase change cycle, including a cooling mode and a heating mode: Cooling mode: The four-way valve is controlled to be in the refrigeration flow direction. The refrigerant discharged from the compressor is divided into two paths. One path enters the refrigerant side of the second heat exchanger, where it exchanges heat with the circulating medium in the negative pressure circulation loop and releases heat. The other path bypasses through the regulating valve. The regulating valve adjusts its opening according to the set temperature to control the refrigerant flow rate through the refrigerant side of the second heat exchanger. After the refrigerants are combined, they enter the condenser through the first and second ports of the four-way valve to dissipate heat. After dissipation, the refrigerant enters the refrigerant side of the first heat exchanger after being throttled by the expansion valve. It exchanges heat with the circulating medium in the negative pressure circulation loop and absorbs heat. After absorbing heat, the refrigerant returns to the compressor through the third and fourth ports of the four-way valve. In the negative pressure circulation loop, the vacuum pump establishes a negative pressure environment corresponding to the target temperature at the load interface. The circulation pump drives the circulation medium to flow through the circulation medium side of the first heat exchanger and is cooled. Then it flows through the circulation medium side of the second heat exchanger and is reheated and temperature controlled. It is then delivered to the load interface and undergoes a boiling phase change in the negative pressure environment to absorb heat. Heating mode: The four-way valve is controlled to be in the heating direction, and the regulating valve is closed. The refrigerant discharged from the compressor flows through the refrigerant side of the second heat exchanger, where it exchanges heat with the circulating medium in the negative pressure circulation loop and releases heat. After releasing heat, the refrigerant enters the refrigerant side of the first heat exchanger through the first and third ports of the four-way valve, where it exchanges heat with the circulating medium in the negative pressure circulation loop and further releases heat. Then, the refrigerant enters the condenser to absorb heat after being throttled by the expansion valve. After absorbing heat, the refrigerant returns to the compressor through the second and fourth ports of the four-way valve. In the negative pressure circulation loop, the vacuum pump establishes a negative pressure environment corresponding to the target temperature at the load interface. The circulation pump drives the circulation medium to flow sequentially through the circulation medium side of the first heat exchanger and the circulation medium side of the second heat exchanger. After being heated, the medium is delivered to the load interface. The heated circulation medium partially vaporizes under the negative pressure environment, and the resulting vapor condenses and undergoes a phase change at the load interface to release heat.

[0013] In one embodiment of the present invention, in the cooling mode: The temperature of the circulating medium after flowing through the first heat exchanger is cooled to a level below the target set temperature at the load interface. The temperature of the circulating medium after flowing through the second heat exchanger is reheated to be equal to or close to the target set temperature.

[0014] In one embodiment of the present invention, in the cooling mode, after the circulating medium driven by the circulating pump is cooled on the circulating medium side of the first heat exchanger, the temperature is maintained in the range of 15°C to 30°C to ensure that the circulating pump operates in the high-efficiency operating temperature range. In heating mode, the refrigerant discharged from the compressor heats the circulating medium in the second heat exchanger, and the temperature of the circulating medium reaches 70°C to 85°C; then, the heater is turned on to further heat the circulating medium to a target temperature higher than 85°C.

[0015] The technical solution of the present invention has the following advantages over the prior art: The integrated negative pressure phase change cycle dual-condition heat pump system and its cooling and heating method described in this invention integrate a heat pump system with a negative pressure cycle system, and utilize a first heat exchanger and a second heat exchanger to achieve heat exchange between the two. The system can switch the refrigerant flow direction via a four-way valve according to cooling or heating needs. Simultaneously, the negative pressure cycle system establishes a negative pressure environment at the load interface, thereby achieving efficient phase change heat transfer while effectively utilizing the heat from the heat pump system under different operating conditions, improving system integration and energy utilization efficiency. Attached Figure Description

[0016] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a structural framework diagram of the dual-condition heat pump system with integrated negative pressure phase change cycle of the present invention.

[0017] Explanation of reference numerals in the accompanying drawings: 1. First heat exchanger; 2. Second heat exchanger; 3. Compressor; 4. Four-way valve; 5. Condenser; 6. Expansion valve; 7. Regulating valve; 8. Vacuum pump; 9. Circulation pump; 10. Water tank; 11. First temperature detection device; 12. Second temperature detection device; 13. Third temperature detection device; 14. Fourth temperature detection device; 15. Pressure detection device; 16. Heater. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0019] Reference Figure 1As shown, the present invention provides a dual-condition heat pump system with integrated negative pressure phase change cycle and its cooling and heating methods to solve the aforementioned problems existing in the prior art. In the technical solution proposed in this invention, the system consists of a heat pump system, a negative pressure cycle system, and a first heat exchanger 1 and a second heat exchanger 2 for heat exchange between the two. Both the first heat exchanger 1 and the second heat exchanger 2 have a refrigerant side connected to the heat pump system and a circulating medium side connected to the negative pressure cycle system, forming a thermal coupling interface between the two systems. The heat pump system also includes a compressor 3, a four-way valve 4, a condenser 5, an expansion valve 6, and a regulating valve 7. The discharge port of the compressor 3 is connected to both the refrigerant inlet of the second heat exchanger 2 and the inlet of the regulating valve 7. The refrigerant outlet of the second heat exchanger 2 merges with the outlet of the regulating valve 7 and connects to the first port of the four-way valve 4. The second port of the four-way valve 4 is connected to the refrigerant side of the first heat exchanger 1 via the condenser 5 and the expansion valve 6. The refrigerant outlet of the first heat exchanger 1 is connected to the third port of the four-way valve 4. The fourth port of the four-way valve 4 is connected to the suction port of the compressor 3. By controlling the reversal of the four-way valve 4, the system can switch between cooling and heating flow directions, thereby changing the circulation path of the refrigerant in the heat pump system. The negative pressure circulation system includes a vacuum pump 8, a circulation pump 9, a water tank 10, and a load interface for connecting the end load. The vacuum pump 8 is connected to the load interface to establish a negative pressure environment. The outlet of the circulation pump 9 is connected to the circulation medium side inlet of the first heat exchanger 1 and the second heat exchanger 2, respectively, to drive the circulation medium to flow through the two heat exchangers.

[0020] In terms of specific operation, this invention achieves wide-range, high-precision temperature control through two working modes: cooling mode and heating mode. In cooling mode, the four-way valve 4 switches to the cooling flow direction, and the high-temperature, high-pressure refrigerant gas discharged from the compressor 3 is divided into two paths. One path enters the refrigerant side of the second heat exchanger 2, where it exchanges heat with the circulating medium flowing through it and releases some heat. The other path bypasses through the regulating valve 7. The opening of the regulating valve 7 can precisely control the refrigerant flow through the refrigerant side of the second heat exchanger 2, thereby achieving fine adjustment of the reheat of the circulating medium. The combined refrigerant enters the condenser 5 through the four-way valve 4 for further heat dissipation, and then enters the refrigerant side of the first heat exchanger 1 after being throttled and cooled by the expansion valve 6. Here, it absorbs heat from the circulating medium flowing through it, thus deeply cooling it. The heat-absorbing refrigerant returns to the compressor 3 through the four-way valve 4, completing the heat pump cycle. At the same time, in the negative pressure circulation system, the vacuum pump 8 establishes a negative pressure environment corresponding to the target temperature at the load interface, which significantly reduces the boiling point of the circulating medium. The circulating pump 9 drives the circulating medium to first flow through the circulating medium side of the first heat exchanger 1, where it is cooled to a level below the target temperature to provide sufficient cooling capacity reserve. Subsequently, at least a portion of the circulating medium flows through the circulating medium side of the second heat exchanger 2, where it is precisely reheated back to the required target temperature through heat exchange with the high-temperature refrigerant, and finally delivered to the load interface. Under negative pressure, the circulating medium undergoes a boiling phase change when in contact with a higher-temperature load, efficiently absorbing heat using its latent heat of vaporization. The resulting gas-liquid two-phase fluid then returns to the water tank 10, completing the negative pressure cycle. In this process, the first heat exchanger 1 provides the basic cooling capacity, achieving a wide-range cooling, while the second heat exchanger 2 uses the waste heat from the compressor 3 for precise reheating. The temperature is finely adjusted by regulating the flow distribution through the regulating valve 7. The two work together to form a tiered temperature control strategy of "deep cooling first, then precise reheating," effectively solving the problems of lag in response and poor steady-state accuracy in single-stage cooling control.

[0021] In heating mode, the four-way valve 4 switches to the heating flow direction, and the regulating valve 7 closes. All the high-temperature refrigerant discharged from the compressor 3 flows through the refrigerant side of the second heat exchanger 2, releasing heat to the circulating medium flowing through it. The refrigerant, after releasing heat, enters the refrigerant side of the first heat exchanger 1 through the four-way valve 4, further releasing heat to the circulating medium, achieving two-stage heat release. Subsequently, the refrigerant enters the condenser 5 after being throttled by the expansion valve 6, absorbing heat from the environment, and then returns to the compressor 3 through the four-way valve 4. In the negative pressure circulation system, the vacuum pump 8 also establishes a negative pressure environment at the load interface to lower the boiling point. The circulation pump 9 drives the circulating medium to flow sequentially through the circulating medium sides of the first heat exchanger 1 and the second heat exchanger 2, where it is heated step by step. After the high-temperature circulating medium enters the load interface, some of the liquid flashes vapor in the negative pressure environment. The resulting high-temperature vapor undergoes a condensation phase change upon contact with the lower-temperature load surface, efficiently releasing heat using its latent heat of condensation. By combining the two-stage heat release of the heat pump system with phase change heat transfer under negative pressure, the system can achieve efficient heating output at a relatively low compressor exhaust temperature, breaking through the bottleneck of limited heating temperature in traditional heat pumps.

[0022] Compared with the prior art, the beneficial effects of the present invention include: First, by introducing a negative pressure environment, the saturation temperature of the circulating medium is significantly reduced, enabling the system to achieve boiling or condensation phase change under near-normal or even low-temperature conditions. This fully utilizes the inherent advantages of the phase change process, such as large latent heat and high heat transfer coefficient. Its heat transfer efficiency is several times that of traditional single-phase liquid cooling schemes, and it can transfer higher heat flux density at the same flow rate, or significantly reduce the required working fluid circulation volume and pumping power consumption under the same heat load.

[0023] Secondly, the tiered temperature control architecture adopted in the cooling mode, which first cools and then reheats, decomposes the temperature control into two stages: coarse adjustment of the first heat exchanger 1 and fine adjustment of the second heat exchanger 2. The first heat exchanger 1 is responsible for providing a stable and sufficient cooling capacity, while the second heat exchanger 2 uses the exhaust waste heat of the compressor 3, which would otherwise be lost, for rapid and accurate temperature correction. This not only achieves high-precision control of the terminal liquid supply temperature and improves temperature uniformity, but also realizes tiered energy utilization and improves the overall energy efficiency of the system.

[0024] Furthermore, this invention achieves flexible switching between cooling and heating modes through a heat pump system coupled with the flow direction switching of the four-way valve 4. The structure is compact and highly integrated. In heating mode, the refrigerant releases heat sequentially in the first heat exchanger 1 and the second heat exchanger 2, realizing a two-stage heat release. Combined with the negative pressure phase change heat absorption process, this effectively enhances the heating capacity. In summary, the technical solution provided by this invention has achieved significant technological advancements in heat transfer efficiency, temperature control accuracy, energy utilization, and system integration.

[0025] In the process of implementing the above system, it is also necessary to monitor the temperature and pressure status of key points inside the system in real time and accurately, so as to achieve the regulation of cooling and heating. Specifically, this application further proposes to add multiple detection devices to the negative pressure circulation system, which also includes: a first temperature detection device 11, a second temperature detection device 12, a third temperature detection device 13, and a pressure detection device 15.

[0026] The first temperature detection device 11 is located at the outlet of the circulating medium side of the first heat exchanger 1. Its main function is to detect the temperature of the circulating medium after it flows through the first heat exchanger 1. This device typically uses high-precision thermistors, thermocouples, or platinum resistance temperature sensors to acquire real-time temperature data of the circulating medium through direct contact or non-contact methods and transmit the data to the system controller. By monitoring this temperature, the cooling or preheating effect of the first heat exchanger 1 on the circulating medium can be evaluated, and the temperature can be adjusted in real time by dynamically adjusting the opening of the expansion valve 6.

[0027] Specifically, when the temperature detected by the first temperature detection device 11 is higher than the first preset target temperature range, the opening of the expansion valve 6 is increased; when the temperature detected by the first temperature detection device 11 is lower than the first preset target temperature range, the opening of the expansion valve 6 is decreased.

[0028] The expansion valve 6 is typically an electronic expansion valve, whose opening degree can be precisely adjusted by receiving electrical signals from the controller. As a throttling element in the heat pump system, the opening degree of the expansion valve 6 directly determines the refrigerant flow rate and evaporation pressure entering the refrigerant side of the first heat exchanger 1. When the first temperature detection device 11 detects that the temperature of the circulating medium flowing through the first heat exchanger 1 is too high, it indicates that the cooling capacity of the first heat exchanger 1 is insufficient. At this time, the controller will instruct the expansion valve 6 to increase its opening degree to increase the refrigerant flow rate, thereby enhancing the heat absorption capacity of the first heat exchanger 1 and causing the circulating medium temperature to drop back to the target range. Conversely, when the detected temperature is too low, the opening degree of the expansion valve 6 will be reduced to decrease the refrigerant flow rate and avoid overcooling.

[0029] The second temperature detection device 12 is installed at the outlet of the circulating medium side of the second heat exchanger 2 to detect the temperature of the circulating medium after it flows through the second heat exchanger 2. Similar to the first temperature detection device 11, this device also employs reliable temperature sensing technology to provide real-time feedback on the temperature state of the circulating medium after heat exchange in the second heat exchanger 2. This is crucial for understanding the heat load of the second heat exchanger 2 and the final temperature regulation effect on the circulating medium. By monitoring this temperature, the cooling or preheating effect of the second heat exchanger 2 on the circulating medium can be evaluated, and the temperature can be adjusted in real-time by dynamically adjusting the opening of the regulating valve 7.

[0030] Specifically, when the temperature detected by the second temperature detection device 12 is higher than the second preset target temperature, the opening of the regulating valve 7 is increased to reduce the refrigerant flow rate through the refrigerant side of the second heat exchanger 2; when the temperature detected by the second temperature detection device 12 is lower than the second preset target temperature, the opening of the regulating valve 7 is decreased to increase the refrigerant flow rate through the refrigerant side of the second heat exchanger 2.

[0031] The regulating valve 7 controls the flow rate of refrigerant discharged from the compressor 3 into the refrigerant side of the second heat exchanger 2. This regulating valve 7 can be an electric regulating valve or a solenoid valve, and its opening degree is adjusted by the controller based on real-time temperature feedback. In cooling mode, the second heat exchanger 2 is mainly used for reheating and temperature control of the circulating medium after it has been cooled by the first heat exchanger 1. When the second temperature detection device 12 detects that the temperature of the circulating medium flowing through the second heat exchanger 2 is higher than the second preset target temperature, it indicates that the reheat is too high. At this time, the controller will instruct the regulating valve 7 to increase its opening degree, allowing more refrigerant to bypass, thereby reducing the refrigerant flow rate through the refrigerant side of the second heat exchanger 2 and lowering the reheat. Conversely, when the detected temperature is lower than the second preset target temperature, the opening degree of the regulating valve 7 is reduced to increase the refrigerant flow rate through the refrigerant side of the second heat exchanger 2 and increase the reheat.

[0032] The third temperature sensing device 13 is located at the load interface and its function is to detect the temperature of the circulating medium delivered to the end load. This device directly reflects the quality of heat or cold provided by the system to the user or process and is a key indicator for measuring whether the system meets the end load requirements. It can be implemented using an embedded temperature probe or a surface-mount sensor to ensure the accuracy of the measurement results.

[0033] A pressure detection device 15 is installed at the load interface to detect the pressure at the load interface. Due to the characteristics of the negative pressure phase change cycle, the pressure at the load interface directly determines the boiling or condensation temperature of the circulating medium. This device typically uses a piezoresistive, capacitive, or strain gauge pressure sensor, which can accurately measure the absolute or relative pressure under negative pressure conditions and convert the pressure signal into an electrical signal for processing by the controller.

[0034] In actual operation, accurately setting the negative pressure value at the load interface based on the detected target temperature of the circulating medium to ensure stable boiling phase change of the circulating medium at that temperature, thereby achieving efficient and precise temperature control, is a technical problem that needs to be solved. If the negative pressure setting is inaccurate, the phase change temperature may deviate from the expected value, affecting the cooling or heating efficiency of the system.

[0035] In this regard, this application further proposes that the pressure value P of the negative pressure environment established by the vacuum pump 8 at the load interface is set according to the target temperature T detected by the third temperature detection device 13 according to the following relationship: P = A × T 4 -B×T3 +C×T 2 -D×T+E, where, when the circulating medium is water, A=0.0000012136, B=0.0001043992, C=0.0108137083, D=0.2908714719, E=5.3000714286.

[0036] Specifically, the core of this technical solution lies in establishing a precise mathematical relationship between the target temperature T and the required negative pressure value P. The control unit in the system receives the target temperature T detected by the third temperature detection device 13 and calculates the saturation pressure P required for the circulating medium (e.g., water) to undergo a phase change at that target temperature using a preset mathematical formula. This calculated pressure value P is then used as a command to control the vacuum pump 8. The vacuum pump 8 adjusts its operating state according to this command (e.g., by adjusting the speed, start-stop frequency, or valve opening) to accurately establish and maintain the negative pressure environment at the load interface. The pressure detection device 15 monitors the actual pressure at the load interface in real time and feeds the data back to the control unit, forming a closed-loop control to ensure the accuracy of the negative pressure environment.

[0037] Wherein, the relation P = A × T 4 -B×T 3 +C×T 2 -D×T+E is a polynomial fitting model used to accurately describe the saturated vapor pressure curve of the circulating medium within a certain temperature range. This model, through its continuous function form, avoids the interpolation errors or resolution limitations that may exist in traditional lookup tables, thus providing a highly accurate corresponding pressure value P for any target temperature T. The application of this mathematical model enables the system to achieve refined and dynamic control of the negative pressure environment.

[0038] When the circulating medium is water, the coefficients A, B, C, D, and E in the formula are set to specific values: A = 0.0000012136, B = 0.0001043992, C = 0.0108137083, D = 0.2908714719, and E = 5.3000714286. These coefficients are derived from precise measurements or calculations based on the physical properties of water (such as its saturated vapor pressure curve). Presetting these specific coefficients in the system's control program ensures that when the system uses water as the circulating medium, optimal and precise negative pressure control can be achieved based on its inherent thermodynamic properties.

[0039] In practical use, compared with other circulating media, it is necessary to conduct experiments to refit and calculate the values ​​of coefficients A, B, C, D, and E in the relationship.

[0040] Through the above technical solution, the system can accurately calculate and establish a negative pressure environment at the load interface based on actual needs or the target temperature set by the user. This precise control based on a mathematical model ensures that the circulating medium can stably and efficiently undergo boiling or condensation phase change at the expected target temperature, thereby significantly improving the cooling or heating efficiency of the heat pump system. Compared with empirical or coarse pressure control methods, this solution can achieve more accurate temperature output and more stable system operation, effectively avoiding phase change temperature deviation caused by inaccurate negative pressure setting, thus optimizing the heat exchange process, improving energy utilization, and providing a more reliable and comfortable temperature environment for the terminal load.

[0041] In practical applications, especially in heating mode, relying solely on a heat pump system for heat exchange may not be sufficient to heat the circulating medium to the high temperatures required for certain applications, or the operating efficiency of the heat pump may drop significantly when attempting to reach extremely high temperatures, thus limiting the system's application range and energy efficiency performance.

[0042] To address this, this application further proposes adding a heater 16 to the negative pressure circulation system. This heater 16 is an energy conversion device that converts electrical energy, heat energy generated from gas combustion, or other forms of energy into heat to increase the temperature of the circulating medium flowing through it. Specifically, the heater 16 can take the form of an electric heating rod, a gas burner, or a steam coil. For example, when using an electric heating rod, it typically contains a resistance wire. When energized, the resistance wire heats up and transfers heat to the circulating medium through conduction or convection. The design of the heater 16 should consider its heating power, medium flow rate, pressure resistance, and corrosion resistance to ensure safe and efficient operation under negative pressure conditions.

[0043] The heater 16 is cleverly connected in series in the pipeline between the circulating medium side outlet and the load interface of the second heat exchanger 2. This arrangement ensures that the circulating medium, after being initially heated by the second heat exchanger 2 of the heat pump system, can immediately enter the heater 16 for secondary or supplementary heating. This series connection allows the heater 16 to further increase the temperature of the already heated circulating medium, thereby achieving a higher outlet water temperature. The pipeline connections should be made of materials resistant to negative pressure and high temperature, and the sealing of the connections should be ensured to maintain the vacuum state of the negative pressure circulation system.

[0044] When the system is in heating mode, heater 16 is activated and put into operation. Its core function is to further heat the circulating medium, meaning that heater 16 is not the sole heat source, but rather a supplement to the heat pump system. After the heat pump system heats the circulating medium to a certain temperature through the second heat exchanger 2, if this temperature still does not reach the higher target temperature required by the terminal load, heater 16 will start to provide additional heat to the circulating medium, bringing its temperature to or exceeding the preset high-temperature requirement. This control strategy allows the heat pump to operate in a more efficient temperature range, with heater 16 responsible for providing the final temperature boost, thereby optimizing the overall system's energy efficiency and temperature control accuracy.

[0045] Furthermore, the negative pressure circulation system also includes a fourth temperature detection device 14, which is located after the heater 16 and is used to detect the temperature of the circulating medium after being heated by the heater 16, so as to control the heater 16.

[0046] Specifically, the fourth temperature detection device 14 is a sensor for measuring temperature, capable of converting the measured temperature signal into an electrical signal output. This device can be implemented in various forms. For example, a high-precision resistance temperature detector (RTD) (such as Pt100 or Pt1000) can be used, whose resistance changes with temperature, allowing the temperature to be obtained by measuring the resistance value; a thermocouple (such as K-type or T-type) can also be used, which generates a thermoelectric electromotive force based on the Seebeck effect to indicate temperature; or a semiconductor temperature sensor (such as an NTC thermistor or integrated temperature sensor) can be used, whose resistance or output voltage has a specific relationship with temperature. Placing the fourth temperature detection device 14 after the heater 16 ensures that it can accurately detect the actual outlet temperature of the circulating medium after being heated by the heater 16, rather than the temperature before heating. This is crucial for the subsequent precise control of the output power of the heater 16. The core function of this device is to obtain the actual temperature of the circulating medium at the outlet of the heater 16 in real time and accurately. By acquiring temperature data, the system can adjust the operating status of heater 16. For example, a controller (such as a PID controller or PLC) can receive the signal from the fourth temperature detection device 14 and output a control signal to heater 16 based on the deviation between the set value and the actual value, so as to adjust the power supply voltage, current or on / off time of heater 16, thereby achieving precise control of heater 16.

[0047] In some embodiments described above in this application, the negative pressure circulation system establishes a negative pressure environment at the load interface through the vacuum pump 8 to achieve a phase change of the circulating medium. However, conventional vacuum pumps 8 typically require an independent power source, which not only increases the system's energy consumption but may also make the overall system structure and control more complex.

[0048] In this regard, this application further proposes that the negative pressure circulation system also includes an ejector pump, which is associated with the vacuum pump 8. The power inlet of the ejector pump is connected to the outlet of the circulation pump 9, and is used to receive part of the circulating medium discharged by the circulation pump 9 as a power source to drive the vacuum pump 8 to work.

[0049] An ejector pump is a device that uses the momentum of a high-speed fluid (power fluid) to draw in a low-speed fluid (the fluid being drawn in) and deliver it to a higher pressure. In this application, the ejector pump is designed to provide driving force or directly generate negative pressure to replace or assist a conventional mechanical vacuum pump 8. Its working principle is that the power fluid is accelerated through a nozzle, forming a low-pressure zone, thereby drawing in the fluid being drawn in, mixing it with the power fluid, and then discharging it. The ejector pump is associated with the vacuum pump 8, meaning that the ejector pump works in conjunction with the vacuum pump 8, which is responsible for establishing a negative pressure environment at the load interface. Specifically, the ejector pump can act as a drive unit for the vacuum pump 8, providing it with the necessary power, or the ejector pump itself can function as a fluid-driven vacuum pump 8, directly performing the vacuuming task. This setup aims to utilize the existing fluid power within the system, reducing dependence on external energy sources. A circulation pump 9 is responsible for driving the flow of the circulating medium in the negative pressure circulation system. By connecting the power inlet of the ejector pump to the outlet of the circulation pump 9, the ejector pump can directly utilize the high-pressure circulating medium discharged by the circulation pump 9 as its driving fluid. This means that no separate power source is needed to drive the ejector pump, thus achieving efficient energy utilization and system integration. The circulating medium discharged by the circulating pump 9 has a certain pressure and flow rate. The ejector pump utilizes the kinetic energy of this circulating medium, generating a low-pressure area through its internal nozzle effect, thereby driving the vacuum pump 8, or directly establishing the required negative pressure at the load interface. This method effectively combines the function of transporting the circulating medium with the driving function of the vacuum pump 8, improving the overall efficiency of the system.

[0050] The dual-condition heat pump system with integrated negative pressure phase change cycle based on the above embodiments provides a hardware foundation for achieving efficient cooling and heating. In order to fully utilize the potential of the system and ensure accurate and stable temperature control under different operating conditions, the present invention also provides a cooling and heating method applied to the above-mentioned dual-condition heat pump system with integrated negative pressure phase change cycle, including a cooling mode and a heating mode.

[0051] In cooling mode, the four-way valve 4 is first controlled to flow in the cooling direction. The four-way valve 4 is a key component of the heat pump system; by changing the position of its internal valve core, it can switch the refrigerant flow direction, thereby achieving the system's cooling or heating function. In cooling mode, the four-way valve 4 is configured to direct the high-temperature, high-pressure refrigerant discharged from the compressor 3 to the condenser 5, or partially to the second heat exchanger 2, while the low-temperature, low-pressure refrigerant from the evaporator (i.e., the first heat exchanger 1) flows back to the compressor 3's suction port, completing the refrigeration cycle. Specifically, the high-temperature, high-pressure refrigerant discharged from the compressor 3 is divided into two paths. One path enters the refrigerant side of the second heat exchanger 2, where it exchanges heat with the circulating medium in the negative pressure circulation loop and releases heat. This split-flow design aims to achieve precise control of the cooling capacity and efficient energy utilization. A portion of the high-temperature, high-pressure refrigerant enters the second heat exchanger 2, transferring its heat to the circulating medium in the negative pressure circulation loop, reheating and controlling the temperature of the circulating medium to ensure that its temperature meets requirements before entering the load interface. The other refrigerant bypasses through the regulating valve 7. The regulating valve 7 is typically a variable flow control valve, whose opening degree can be adjusted in real time by the controller based on a preset target temperature or the actual detected temperature signal. By changing the opening degree of the regulating valve 7, the refrigerant flow rate entering the second heat exchanger 2 can be precisely controlled, thereby regulating the heating amount of the negative pressure circulating medium by the second heat exchanger 2, ensuring that the circulating medium reaches the required temperature before entering the load interface. After the refrigerants merge, they enter the condenser 5 for heat dissipation through the first and second interfaces of the four-way valve 4. The condenser 5 is the main device for the refrigerant to release heat to the external environment. The high-temperature and high-pressure refrigerant condenses and releases heat here, becoming a high-pressure liquid. After heat dissipation, the refrigerant enters the refrigerant side of the first heat exchanger 1 after being throttled by the expansion valve 6, where it exchanges heat with the circulating medium in the negative pressure circulation loop and absorbs heat. When the high-pressure liquid refrigerant passes through the expansion valve 6, its pressure and temperature drop sharply, becoming a low-temperature and low-pressure two-phase fluid. Subsequently, this low-temperature and low-pressure refrigerant enters the first heat exchanger 1, acting as an evaporator, absorbing heat from the circulating medium in the negative pressure circulation loop, causing it to evaporate, thereby cooling the circulating medium. After absorbing heat, the refrigerant returns to the compressor 3 through the third and fourth ports of the four-way valve 4, completing one refrigeration cycle. In the negative pressure circulation loop, the vacuum pump 8 establishes a negative pressure environment corresponding to the target temperature at the load port. The vacuum pump 8 operates continuously, maintaining a negative pressure environment below atmospheric pressure at the load port. The pressure value of this negative pressure environment corresponds to the preset target temperature, ensuring that the circulating medium can undergo a boiling phase change at this temperature. The circulation pump 9 drives the circulating medium to flow through the circulating medium side of the first heat exchanger 1, where it is cooled. Then, it flows through the circulating medium side of the second heat exchanger 2, where it is reheated and its temperature controlled. Subsequently, it is delivered to the load port, where it undergoes a boiling phase change under negative pressure to absorb heat. The circulation pump 9 is responsible for driving the circulation medium to flow in the loop. The circulating medium first flows through the first heat exchanger 1, where it is cooled by the refrigerant, lowering its temperature.Subsequently, to precisely control the temperature delivered to the load interface, the circulating medium flows through the second heat exchanger 2, where it is reheated and its temperature controlled through heat exchange with the refrigerant. Finally, the temperature-regulated circulating medium is delivered to the load interface, where, under the negative pressure established by the vacuum pump 8, the circulating medium undergoes a boiling phase change, absorbing heat from the load, thereby achieving a cooling effect.

[0052] In heating mode, the four-way valve 4 is switched to the heating flow direction, and the regulating valve 7 is closed. In heating mode, the four-way valve 4 switches to the heating flow direction, changing the refrigerant circulation path so that the high-temperature, high-pressure refrigerant discharged from the compressor 3 flows to the first heat exchanger 1 and the second heat exchanger 2, releasing heat into the negative pressure circulation loop. Simultaneously, the regulating valve 7 is closed to ensure that all refrigerant discharged from the compressor 3 participates in the heat release process into the negative pressure circulation loop, maximizing heating capacity. The refrigerant discharged from the compressor 3 flows through the refrigerant side of the second heat exchanger 2, exchanging heat with the circulating medium in the negative pressure circulation loop and releasing heat. The high-temperature, high-pressure refrigerant discharged from the compressor 3 first enters the second heat exchanger 2, transferring its heat to the circulating medium in the negative pressure circulation loop, initially heating the circulating medium. After releasing heat, the refrigerant enters the refrigerant side of the first heat exchanger 1 through the first and third ports of the four-way valve 4, exchanging heat with the circulating medium in the negative pressure circulation loop and further releasing heat. After releasing heat in the second heat exchanger 2, the refrigerant, guided by the four-way valve 4, continues into the first heat exchanger 1 to exchange heat with the circulating medium in the negative pressure circulation loop, further releasing heat and reheating the circulating medium to achieve a higher heating temperature. The refrigerant then enters the condenser 5 to absorb heat after being throttled by the expansion valve 6. Having released heat twice, the refrigerant's temperature and pressure have decreased. It then passes through the expansion valve 6 again, further reducing its pressure and temperature, before entering the condenser 5. In heating mode, the condenser 5 acts as an evaporator, absorbing heat from the external environment to evaporate the refrigerant. The refrigerant, after absorbing heat, returns to the compressor 3 through the second and fourth ports of the four-way valve 4, completing one heating cycle. In the negative pressure circulation loop, the vacuum pump 8 establishes a negative pressure environment corresponding to the target temperature at the load port. In heating mode, the vacuum pump 8 also maintains a negative pressure environment corresponding to the target temperature at the load port to promote the phase change of the circulating medium. The circulating pump 9 drives the circulating medium to flow sequentially through the circulating medium side of the first heat exchanger 1 and the second heat exchanger 2, where it is heated and then delivered to the load interface. Under negative pressure, the heated circulating medium partially vaporizes, and the resulting vapor condenses and undergoes a phase change at the load interface, releasing heat. The circulating pump 9 drives the circulating medium to flow sequentially through the first heat exchanger 1 and the second heat exchanger 2, absorbing heat from the refrigerant side and becoming heated. The heated circulating medium is then delivered to the load interface, where, under negative pressure, some of the circulating medium vaporizes to form vapor. This vapor condenses and undergoes a phase change at the load interface, releasing latent heat to the load, thereby achieving a heating effect.

[0053] Specifically, this embodiment further proposes that in cooling mode, the temperature of the circulating medium flowing through the first heat exchanger 1 is cooled to a level below the target set temperature at the load interface; and the temperature of the circulating medium flowing through the second heat exchanger 2 is reheated to equal to or close to the target set temperature. Specifically, in cooling mode, the circulating medium driven by the circulating pump 9 first flows through the circulating medium side of the first heat exchanger 1. During this process, the refrigerant in the heat pump system evaporates and absorbs heat on the refrigerant side of the first heat exchanger 1, thereby cooling the circulating medium. In this embodiment, by precisely controlling the heat exchange capacity of the first heat exchanger 1, for example by adjusting the opening of the expansion valve 6, the temperature of the circulating medium flowing through the first heat exchanger 1 is cooled to a level below the target set temperature at the load interface. This pre-cooling process provides margin for subsequent precise temperature adjustment, ensuring sufficient adjustment space during the subsequent reheating process. Subsequently, the cooled circulating medium continues to flow through the circulating medium side of the second heat exchanger 2, where the refrigerant in the heat pump system condenses and releases heat on the refrigerant side of the second heat exchanger 2, thereby reheating the circulating medium. By adjusting the heat exchange capacity of the second heat exchanger 2, for example by adjusting the opening of the regulating valve 7, the temperature of the circulating medium flowing through the second heat exchanger 2 is precisely reheated to be equal to or close to the target set temperature at the load interface. The target set temperature at the load interface is an ideal temperature determined based on the actual requirements of the terminal load and the negative pressure phase change characteristics to ensure that the circulating medium can efficiently undergo boiling phase change at this temperature.

[0054] Specifically, this embodiment further proposes that in the cooling mode, after the circulating medium driven by the circulating pump 9 is cooled on the circulating medium side of the first heat exchanger 1, its temperature is maintained within the range of 15°C to 30°C to ensure that the circulating pump 9 operates within its efficient operating temperature range. Specifically, as a key component in the negative pressure circulation system, the operating efficiency and lifespan of the circulating pump 9 are significantly affected by the temperature of the circulating medium. When the temperature of the circulating medium is too low, it may cause pressure fluctuations inside the pump body, or even cavitation, thereby reducing the pump's efficiency and shortening its service life; while excessively high temperatures may affect the pump's seals and motor performance. Therefore, precisely controlling the temperature of the circulating medium within the preset range of 15°C to 30°C ensures that the circulating pump 9 is always within its designed efficient operating temperature range, thus guaranteeing the stability and reliability of the system. This temperature control can be achieved by the system controller adjusting parameters such as the opening degree of the expansion valve 6, the opening degree of the regulating valve 7, and the operating frequency of the compressor 3 based on the temperature detected by the first temperature detection device 11, thereby precisely controlling the evaporation temperature and heat absorption of the refrigerant in the first heat exchanger 1, and thus regulating the cooling degree of the circulating medium.

[0055] Meanwhile, in heating mode, the refrigerant discharged from compressor 3 heats the circulating medium in the second heat exchanger 2, raising the medium temperature to 70°C to 85°C. Based on this, heater 16 is then activated to further heat the circulating medium to a target temperature above 85°C. Specifically, the heat pump system uses the high-temperature, high-pressure refrigerant discharged from compressor 3 to exchange heat with the circulating medium in the second heat exchanger 2, raising the medium temperature to a relatively high level of 70°C to 85°C. This temperature range can meet most medium- and high-temperature heating needs. However, for some end loads with higher temperature requirements, such as hot water supply or industrial heating applications requiring 90°C or even higher temperatures, relying solely on the heat pump system may be insufficient. Therefore, this application introduces heater 16, which can be an electric heater 16, a gas heater 16, or other forms of auxiliary heating device. When the system detects a need for a higher temperature output, heater 16 is activated to reheat the circulating medium, which has already been preliminarily heated by the heat pump, further raising its temperature to a preset target temperature above 85°C. The activation of heater 16 and the adjustment of heating power can be precisely controlled based on the temperature detected by the fourth temperature detection device 14 to ensure that the circulating medium can stably reach the required ultra-high temperature.

[0056] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A dual-condition heat pump system integrating a negative pressure phase change cycle, characterized in that, It includes a heat pump system, a negative pressure circulation system, and a first heat exchanger and a second heat exchanger for heat exchange between the heat pump system and the negative pressure circulation system. Both the first heat exchanger and the second heat exchanger have a refrigerant side connected to the heat pump system and a circulating medium side connected to the negative pressure circulation system. The heat pump system also includes a compressor, a four-way valve, a condenser, an expansion valve, and a regulating valve. The compressor's discharge port is connected to the refrigerant-side inlet of the second heat exchanger and to the inlet of the regulating valve. The refrigerant-side outlet of the second heat exchanger merges with the outlet of the regulating valve and is connected to the first port of the four-way valve. The second port of the four-way valve is connected to one end of the condenser, the other end of the condenser is connected to the inlet of the expansion valve, the outlet of the expansion valve is connected to the refrigerant-side inlet of the first heat exchanger, the refrigerant-side outlet of the first heat exchanger is connected to the third port of the four-way valve, and the fourth port of the four-way valve is connected to the compressor's suction port. The four-way valve has both cooling and heating flow directions: in the cooling direction, the first port is connected to the second port, and the third port is connected to the fourth port; in the heating direction, the first port is connected to the third port, and the second port is connected to the fourth port. The negative pressure circulation system includes a vacuum pump, a circulation pump, a water tank, and a load interface for connecting the terminal load; the vacuum pump is connected to the load interface to establish a negative pressure environment at the load interface; the outlet of the circulation pump is connected to the circulation medium side inlet of the first heat exchanger and the circulation medium side inlet of the second heat exchanger, respectively.

2. The dual-condition heat pump system with integrated negative pressure phase change cycle according to claim 1, characterized in that: The negative pressure circulation system also includes: The first temperature detection device is installed at the outlet of the circulating medium side of the first heat exchanger and is used to detect the temperature of the circulating medium after flowing through the first heat exchanger. The second temperature detection device is installed at the outlet of the second heat exchanger on the circulating medium side and is used to detect the temperature of the circulating medium after flowing through the second heat exchanger. The third temperature detection device is located at the load interface and is used to detect the temperature of the circulating medium delivered to the end load. A pressure detection device is installed at the load interface to detect the pressure at the load interface.

3. The dual-condition heat pump system with integrated negative pressure phase change cycle according to claim 2, characterized in that: The pressure value P of the negative pressure environment established by the vacuum pump at the load interface is set according to the target temperature T detected by the third temperature detection device according to the following formula: P=A×T 4 -B×T 3 +C×T 2 -D×T+E; When the circulating medium is water, A=0.0000012136, B=0.0001043992, C=0.0108137083, D=0.2908714719, E=5.3000714286.

4. The dual-condition heat pump system with integrated negative pressure phase change cycle according to claim 2, characterized in that: The opening degree of the expansion valve is adjusted according to the temperature detected by the first temperature detection device: when the temperature detected by the first temperature detection device is higher than the first preset target temperature range, the opening degree of the expansion valve is increased; when the temperature detected by the first temperature detection device is lower than the first preset target temperature range, the opening degree of the expansion valve is decreased. The opening of the regulating valve is adjusted according to the temperature detected by the second temperature detection device: when the temperature detected by the second temperature detection device is higher than the second preset target temperature, the opening of the regulating valve is increased to reduce the refrigerant flow through the refrigerant side of the second heat exchanger; when the temperature detected by the second temperature detection device is lower than the second preset target temperature, the opening of the regulating valve is decreased to increase the refrigerant flow through the refrigerant side of the second heat exchanger.

5. The dual-condition heat pump system with integrated negative pressure phase change cycle according to claim 1, characterized in that: The negative pressure circulation system also includes a heater, which is connected in series in the pipeline between the circulating medium side outlet of the second heat exchanger and the load interface; In heating mode, the heater is turned on to further heat the circulating medium.

6. The dual-condition heat pump system with integrated negative pressure phase change cycle according to claim 5, characterized in that: The negative pressure circulation system also includes a fourth temperature detection device, which is installed after the heater to detect the temperature of the circulating medium after it has been heated by the heater, thereby enabling control of the heater.

7. The dual-condition heat pump system with integrated negative pressure phase change cycle according to claim 1, characterized in that: The negative pressure circulation system also includes an ejector pump, which is associated with the vacuum pump. The power inlet of the ejector pump is connected to the outlet of the circulation pump, and is used to receive part of the circulating medium discharged by the circulation pump as a power source to drive the vacuum pump.

8. A cooling and heating method applied to a dual-condition heat pump system with integrated negative pressure phase change cycle as described in any one of claims 1 to 7, comprising a cooling mode and a heating mode, characterized in that: Cooling mode: The four-way valve is controlled to be in the refrigeration flow direction. The refrigerant discharged from the compressor is divided into two paths. One path enters the refrigerant side of the second heat exchanger, where it exchanges heat with the circulating medium in the negative pressure circulation loop and releases heat. The other path bypasses through the regulating valve. The regulating valve adjusts its opening according to the set temperature to control the refrigerant flow rate through the refrigerant side of the second heat exchanger. After the refrigerants are combined, they enter the condenser through the first and second ports of the four-way valve to dissipate heat. After dissipation, the refrigerant enters the refrigerant side of the first heat exchanger after being throttled by the expansion valve. It exchanges heat with the circulating medium in the negative pressure circulation loop and absorbs heat. After absorbing heat, the refrigerant returns to the compressor through the third and fourth ports of the four-way valve. In the negative pressure circulation loop, the vacuum pump establishes a negative pressure environment corresponding to the target temperature at the load interface. The circulation pump drives the circulation medium to flow through the circulation medium side of the first heat exchanger and is cooled. Then it flows through the circulation medium side of the second heat exchanger and is reheated and temperature controlled. It is then delivered to the load interface and undergoes a boiling phase change in the negative pressure environment to absorb heat. Heating mode: The four-way valve is controlled to be in the heating direction, and the regulating valve is closed. The refrigerant discharged from the compressor flows through the refrigerant side of the second heat exchanger, where it exchanges heat with the circulating medium in the negative pressure circulation loop and releases heat. After releasing heat, the refrigerant enters the refrigerant side of the first heat exchanger through the first and third ports of the four-way valve, where it exchanges heat with the circulating medium in the negative pressure circulation loop and further releases heat. Then, the refrigerant enters the condenser to absorb heat after being throttled by the expansion valve. After absorbing heat, the refrigerant returns to the compressor through the second and fourth ports of the four-way valve. In the negative pressure circulation loop, the vacuum pump establishes a negative pressure environment corresponding to the target temperature at the load interface. The circulation pump drives the circulation medium to flow sequentially through the circulation medium side of the first heat exchanger and the circulation medium side of the second heat exchanger. After being heated, the medium is delivered to the load interface. The heated circulation medium partially vaporizes under the negative pressure environment, and the resulting vapor condenses and undergoes a phase change at the load interface to release heat.

9. The cooling and heating method of the dual-condition heat pump system with integrated negative pressure phase change cycle according to claim 8, characterized in that: In cooling mode: The temperature of the circulating medium after flowing through the first heat exchanger is cooled to a level below the target set temperature at the load interface. The temperature of the circulating medium after flowing through the second heat exchanger is reheated to be equal to or close to the target set temperature.

10. The cooling and heating method of the dual-condition heat pump system with integrated negative pressure phase change cycle according to claim 8, characterized in that: In cooling mode, the circulating medium driven by the circulating pump flows through the circulating medium side of the first heat exchanger and is cooled, and the temperature is maintained in the range of 15°C to 30°C to ensure that the circulating pump operates in the high-efficiency operating temperature range. In heating mode, the refrigerant discharged from the compressor heats the circulating medium in the second heat exchanger, and the temperature of the circulating medium reaches 70°C to 85°C; then, the heater is turned on to further heat the circulating medium to a target temperature higher than 85°C.

Images