A low-temperature evaporation and concentration system and method based on a solar phase change energy storage heat pump

Abstract

This invention relates to the field of low-temperature evaporation and concentration technology, specifically a low-temperature evaporation and concentration system and method based on a solar phase change energy storage heat pump. The system includes a heat storage unit, a heat pump unit, an evaporation and concentration unit, and a vacuum unit. The PVT solar collector is constructed using flat glass, photovoltaic cells, a polyvinyl fluoride composite film, and thermally conductive adhesive, and stores heat through a phase change energy storage tank to achieve low-temperature evaporation and concentration. Under conditions such as increased vacuum, increased ambient temperature, or improved heat exchange performance, the system's energy efficiency ratio and evaporation rate can be effectively improved, resulting in increased heating capacity, reduced power consumption, and improved steam recovery efficiency. This invention can be widely applied in the field of low-temperature evaporation and concentration in industries such as chemical and pharmaceutical manufacturing.

Description

Technical Field

[0001] This invention relates to the field of low-temperature evaporation and concentration technology, and in particular to a low-temperature evaporation and concentration system and method based on a solar phase change energy storage heat pump. Background Technology

[0002] Economic development and the improvement of people's living standards are inseparable from energy support. Under the major context of "carbon reduction" and "dual control of energy consumption," improving energy efficiency is imperative. Statistics show that currently, energy consumption in my country's industrial sector accounts for more than 60% of the country's total energy consumption. Reducing industrial energy consumption, improving energy efficiency in industrial production, and fully recovering and utilizing waste heat are issues that need to be addressed at this stage.

[0003] In evaporation and concentration operations, heat pump evaporation and multi-effect evaporation are the two main ways to improve energy efficiency. In multi-effect evaporation, steam is generated using coal-fired boilers or electric heating to heat the raw material liquid for evaporation and concentration. This results in: 1. a significant waste of energy; 2. the high specific volume of steam, placing high demands on the compressor; 3. the need to maintain good airtightness, thus requiring high-quality equipment; and 4. the need for high energy consumption in the evaporation and concentration of materials that are heat-sensitive or corrosive. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems of energy waste and high vacuum requirements of compressors in the above or existing technologies, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to provide a low-temperature evaporation and concentration system and method based on a solar phase change energy storage heat pump.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a heat storage unit, including a PVT solar collector, a solenoid valve, and a phase change energy storage box, wherein one side of the solenoid valve is connected to the phase change energy storage box and the other side is connected to the PVT solar collector;

[0008] The heat pump unit includes an air-cooled finned evaporator, a compressor, a four-way valve, a phase change energy storage tank, and a throttling valve. The air-cooled finned evaporator is connected to the four-way valve on one side and the throttling valve on the other side. The compressor is connected to the four-way valve on one side and the phase change energy storage tank on the other side.

[0009] As a preferred embodiment of the low-temperature evaporation and concentration system based on solar phase change energy storage heat pump of the present invention, the evaporation and concentration unit includes an evaporation and concentration tank, an insulation layer, a stirrer, a vacuum gauge, an antifoaming component, a stirring plate, a heating coil, a water pump, a raw material tank, and a concentrated liquid tank. The stirrer is connected to one side of the evaporation and concentration tank, the vacuum gauge is located on one side of the evaporation and concentration tank, the insulation layer is located on the inner wall of the evaporation and concentration tank, the antifoaming component is located inside the evaporation and concentration tank, the output end of the stirrer extends into the evaporation and concentration tank, and the stirring plate is wound around the output end of the stirrer.

[0010] As a preferred embodiment of the low-temperature evaporation and concentration system based on solar phase change energy storage heat pump of the present invention, the vacuum unit comprises an expansion valve, a heat exchanger, a vacuum jetter, a water tank, a porous tube, and a vacuum circulation pump. The heat exchanger is connected to the expansion valve on one side and the vacuum jetter on the other side. The water tank is connected to the vacuum circulation pump on one side and the vacuum jetter on the other side. The porous tube is located inside the water tank.

[0011] As a preferred embodiment of the low-temperature evaporation and concentration system based on solar phase change energy storage heat pump of the present invention, wherein: the PVT solar collector includes flat glass, photovoltaic cells, polyvinyl fluoride composite film and thermally conductive adhesive, heat absorption plate, insulation layer and heat collection tube, the bottom of the flat glass is connected to the photovoltaic cells, the bottom of the polyvinyl fluoride composite film and thermally conductive adhesive is connected to the heat absorption plate, the insulation layer is located at the bottom of the heat absorption plate, and the heat collection tube is located inside the insulation layer.

[0012] As a preferred embodiment of the low-temperature evaporation and concentration system based on solar phase change energy storage heat pump of the present invention, the phase change energy storage box includes a box body, a constant temperature layer, a heat exchange coil, a refrigerant, a filter box, a phase change heat storage ball, and a fixing buckle. The constant temperature layer is located inside the box body, the heat exchange coil is located inside the box body, the refrigerant is wrapped around the outside of the heat exchange coil, the phase change heat storage ball is located inside the filter box, and the fixing buckle is located on the top of the filter box.

[0013] As a preferred embodiment of the low-temperature evaporation and concentration method based on solar phase change energy storage heat pump of the present invention, wherein: by reducing the vacuum degree, the efficiency of the heat exchanger and the steam recovery utilization rate are improved;

[0014] By increasing the vacuum level and reducing energy consumption, the heating capacity is increased while the power consumption is decreased.

[0015] By increasing the vacuum level and temperature, the COP (Coefficient of Performance) and evaporation rate of the heat pump can be improved.

[0016] As a preferred embodiment of the low-temperature evaporation and concentration method based on solar phase change energy storage heat pump of the present invention, the following steps are taken: heating the raw material liquid, controlling the vacuum degree of the evaporation and concentration tank, and increasing the vacuum degree of the vacuum pump.

[0017] As a preferred embodiment of the low-temperature evaporation and concentration method based on solar phase change energy storage heat pump of the present invention, the heat exchange rate is determined by adjusting the vacuum degree and the evaporation temperature; the energy consumption of the compressor is determined by adjusting the vacuum degree and the evaporation temperature of the raw material liquid.

[0018] As a preferred embodiment of the low-temperature evaporation and concentration method based on solar phase change energy storage heat pump of the present invention, the COP and evaporation rate are changed by adjusting the vacuum degree; the compressor exhaust temperature, system energy consumption, heating capacity, evaporation rate and COP rise and fall are determined by adjusting the rise and fall of ambient temperature.

[0019] As a preferred embodiment of the low-temperature evaporation and concentration method based on solar phase change energy storage heat pump of the present invention, the air temperature and steam utilization rate are changed by adjusting the vacuum degree, the evaporation temperature of the raw liquid, the heat exchange performance and the fan temperature.

[0020] The beneficial effects of the low-temperature evaporation concentration system and method based on solar phase change energy storage heat pump of the present invention are as follows: The application of the present invention can provide efficient, energy-saving, and environmentally friendly low-temperature evaporation concentration technology for industrial production, wastewater treatment, and other fields. This technical solution utilizes a low-temperature evaporation concentration system based on solar energy storage and a heat pump to achieve effective treatment and recycling of raw material liquids such as wastewater, thereby saving energy and resources. Simultaneously, by controlling and adjusting the vacuum degree and ambient temperature, the system's energy efficiency ratio and evaporation rate can be improved, reducing energy consumption and production costs, thus possessing very broad application prospects. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0022] Figure 1 A schematic diagram of the overall system of the present invention.

[0023] Figure 2 This is a schematic diagram of a cross-section of a solar photovoltaic thermal panel.

[0024] Figure 3 This is a schematic diagram of the phase change energy storage box of the present invention.

[0025] Figure 4 A cross-sectional schematic diagram of the phase change energy storage box of the present invention.

[0026] Figure 5 A schematic diagram showing the temperature changes of the feed liquid under different vacuum levels.

[0027] Figure 6Schematic diagram of heat exchange temperature difference and heat exchange volume changes under different vacuum levels.

[0028] Figure 7 A schematic diagram showing the changes in heating capacity and power consumption under different vacuum levels.

[0029] Figure 8 A schematic diagram showing the changes in COP and evaporation rate of a heat pump under different vacuum levels.

[0030] Figure 9 A schematic diagram illustrating the effect of ambient temperature on the temperature of the air after heat exchange.

[0031] Figure 10 A schematic diagram illustrating the effect of ambient temperature on compressor exhaust temperature.

[0032] Figure 11 A schematic diagram illustrating the impact of ambient temperature on system energy consumption and heating capacity.

[0033] Figure 12 Schematic diagram showing the effect of ambient temperature on the system's evaporation rate and COP. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0036] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0037] Example 1

[0038] Reference Figure 1-4 This is the first embodiment of the present invention, which provides a low-temperature evaporation and concentration system based on a solar phase change energy storage heat pump.

[0039] Specifically, the heat storage unit 100 includes a PVT solar collector 101, a solenoid valve 102, and a phase change energy storage box 103. One side of the solenoid valve 102 is connected to the phase change energy storage box 103 and the other side is connected to the PVT solar collector 101.

[0040] The heat pump unit 200 includes an air-cooled finned evaporator 201, a compressor 202, a four-way valve 203, a phase change energy storage box 103, and a throttling valve 204. The air-cooled finned evaporator 201 is connected to the four-way valve 203 on one side and the throttling valve 204 on the other side. The compressor 202 is connected to the four-way valve 203 on one side and the phase change energy storage box 103 on the other side.

[0041] Evaporation and concentration unit 300 includes evaporation and concentration tank 301, insulation layer 302, stirrer 303, vacuum gauge 304, defoaming component 305, stirring blade 306, heating coil 307, water pump 308, raw material tank 309, and concentrated liquid tank 310. Stirrer 303 is connected to one side of evaporation and concentration tank 301. Vacuum gauge 304 is located on one side of evaporation and concentration tank 301. Insulation layer 302 is located on the inner wall of evaporation and concentration tank 301. Defoaming component 305 is located inside evaporation and concentration tank 301. The output end of stirrer 303 extends into evaporation and concentration tank 301. Stirring blade 306 is wound around the output end of stirrer 303.

[0042] The vacuum unit 400 comprises an expansion valve 401, a heat exchanger 402, a vacuum jet injector 403, a water tank 404, a porous tube 405, and a vacuum circulation pump 406. The heat exchanger 402 is connected to the expansion valve 401 on one side and the vacuum jet injector 403 on the other side. The water tank 404 is connected to the vacuum circulation pump 406 on one side and the vacuum jet injector 403 on the other side. The porous tube 405 is located inside the water tank 404.

[0043] The PVT solar collector 101 includes a flat glass plate 101a, a photovoltaic cell 101b, a polyvinyl fluoride composite film and thermally conductive adhesive 101c, a heat-absorbing plate 101d, a heat insulation layer 101e, and a heat-collecting tube 101f. The bottom of the flat glass plate 101a is connected to the photovoltaic cell 101b, the bottom of the polyvinyl fluoride composite film and thermally conductive adhesive 101c is connected to the heat-absorbing plate 101d, the heat insulation layer 101e is located at the bottom of the heat-absorbing plate 101d, and the heat-collecting tube 101f is located inside the heat insulation layer 101e.

[0044] The phase change energy storage box 103 includes a box body 103a, a constant temperature layer 103b, a heat exchange coil 103c, a refrigerant 103d, a filter box 103e, a phase change heat storage ball 103f, and a fixing buckle 103g. The constant temperature layer 103b is located inside the box body 103a, the heat exchange coil 103c is located inside the box body 103a, the refrigerant 103d is wrapped around the outside of the heat exchange coil 103c, the phase change heat storage ball 103f is located inside the filter box 103e, and the fixing buckle 103g is located on the top of the filter box 103e.

[0045] Furthermore, the present invention provides a low-temperature evaporation and concentration system based on a solar phase change energy storage heat pump, including a PVT solar composite heat pump operation mode. When it is a sunny day, the PVT solar collector 101 works alone. Part of the electricity generated by the PV panel is used by the air source heat pump system, and the excess electricity is connected to the power grid. The PVT solar collector 101 serves as a low-temperature heat source, and the working fluid placed in it directly absorbs solar radiation to produce low-temperature hot water. The low-temperature hot water is used for heat storage in the phase change energy storage tank 103.

[0046] In the air-source heat pump operation mode, during nighttime or extreme weather conditions such as continuous cloudy, rainy, or snowy periods when solar radiation is weak and the temperature of the circulating refrigerant in the PT plate is low, the solar heat pump cycle stops, and the system automatically switches to air-source heat pump operation to provide a low-temperature heat source. The operating principle of the air-source heat pump is as follows: the refrigerant evaporates in the air-cooled finned evaporator 201, absorbing heat from the air. After being compressed by the compressor 202, it becomes a high-temperature, high-pressure superheated gaseous refrigerant. The high-temperature, high-pressure refrigerant then passes through the condenser heat exchange coil 603, transferring heat to the low-temperature circulating refrigerant, raising the refrigerant temperature, and storing heat in the phase change energy storage tank 103. Part of the refrigerant enters the throttling valve 204, which throttles the medium-temperature, high-pressure liquid refrigerant into low-temperature, low-pressure wet vapor, which then enters the air-cooled finned evaporator 201 to complete the cycle.

[0047] The phase change energy storage box 103 includes a box body 103a and several filter boxes 103e and several heat exchange coils 103c installed inside the box body 103a. Cooling water flows through the heat exchange coils 103c, and a refrigerant flows through the heat exchange coils 103c. The coils are opened during heat storage. The filter boxes 103e are detachably installed inside the box body 103a. The remaining space inside the box body 103a is filled with a refrigerant 103d. The filter boxes 103e are filled with phase change heat storage balls 103f. The phase change heat storage balls 103f are hollow spheres, and the cavities of the phase change heat storage balls 103f are filled with... The device contains phase change heat storage materials, and the phase change heat storage ball 103f is made of plastic. Phase change heat storage technology utilizes the heat storage material to undergo a phase change to store or utilize heat. The adjustable filter box 103e inside the phase change energy storage box 103 can be pulled out from inside the phase change energy storage box 103 and is fixed inside the phase change energy storage box 103. The phase change heat storage ball 103f is placed inside the adjustable filter box 103e. The phase change heat storage materials can be combined in various ways and placed inside the adjustable protective filter box 103e to ensure that the phase change process occurs in real time and to fully utilize the phase change heat storage function. The inner wall of the housing 103a is coated with a constant temperature layer 103b. The filter box 103e is slidably connected to the housing 103a and is connected to the housing 103a by a fixing buckle 607. The filter box 103e and the housing 103a have a pull-out structure. The filter box 103e is arranged in a 4x4 array inside the housing 103a. The pull-out structure design can effectively solve the problems of difficult selection and replacement of heat storage materials. The filter box 103e includes a top plate, a bottom plate, and a filter plate arranged between the top plate and the bottom plate. The filter plate is arranged along the perimeter of the top plate, and a handle is installed on the top surface of the top plate for easy pulling.

[0048] The dilute material in raw material tank 309 is pumped into evaporation and concentration tank 301 by water pump 308. Under vacuum conditions, the heat from phase change energy storage tank 103 heats the heating coil 307 to the boiling point, initiating boiling and evaporation. During the heating process, the agitator 303 rotates, driving the stirring blades 306 to continuously agitate the liquid, enhancing heat exchange and steam escape while reducing adhesion and coking. The generated steam is purified by defoaming component 305 and then enters the condensation stage above evaporation and concentration tank 301. The concentrated material that meets the processing requirements is discharged through the outlet pipe below evaporation and concentration tank 301 and enters concentrated liquid tank 310.

[0049] The remaining steam and non-condensable gases, such as air, after being processed by the evaporation and concentration tank 301 are discharged through vacuum pumping. The vacuum circulation pump 406 draws water from the water tank 404. A portion of this water is drawn into the water tank 404 via the vacuum ejector 403 and discharged through the porous pipe 405. The remaining portion is sent to the heat exchanger 402 to exchange heat with the refrigerant, increasing the heat recovery of the heat pump system while lowering the water temperature in the water tank 404. A liquid-blocking baffle is installed at the vacuum pumping pipe inlet of the vacuum ejector 403 to prevent the intake of condensate. The porous pipe 405 is located inside the water tank 404 and is submerged in water to directly absorb the remaining steam, thereby improving the efficiency of the vacuum system.

[0050] In summary, phase change energy storage and temperature regulation are achieved through a heat storage unit and a heat pump unit. The phase change heat storage ball 103f in the phase change energy storage tank 103 utilizes phase change heat storage technology to store and utilize heat, while the detachable and adjustable filter box 103e effectively solves the problem of heat storage material replacement. The evaporation and concentration unit 300 achieves the evaporation and concentration of raw materials through a heating coil 307 and a stirrer 303. The vacuum unit 400 recovers residual steam and reduces water temperature through a heat exchanger and a vacuum jet injector.

[0051] Example 2

[0052] Reference Figures 5-12 This is the second embodiment of the present invention. Unlike the previous embodiment, this embodiment provides a low-temperature evaporation and concentration method based on a solar phase change energy storage heat pump.

[0053] Specifically, by reducing the vacuum level, the efficiency of heat exchanger 402 and the steam recovery and utilization rate are improved;

[0054] By increasing the vacuum level and reducing energy consumption, the heating capacity is increased while the power consumption is decreased.

[0055] By increasing the vacuum level and temperature, the COP (Coefficient of Performance) and evaporation rate of the heat pump can be improved.

[0056] Furthermore, the experiment investigated the device performance at vacuum levels of 0.05, 0.06, and 0.07 MPa. During the experiment, the feed rate was kept stable and the ambient temperature was maintained within the range of (26±2)℃.

[0057] S1: As Figure 5 It is known that heating the raw material liquid controls the vacuum level of the evaporation and concentration tank, and increases the vacuum level of the vacuum pump. Figure 5In the diagram, 1 represents 0.05 MPa; 2 represents 0.06 MPa; and 3 represents 0.07 MPa. For each group of experiments, under stable room temperature conditions, the heat pump was first turned on to heat the raw material solution to 55°C. Then, the vacuum degree of the evaporation and concentration tank was controlled, and the evaporation temperature of the raw material solution was measured at vacuum degrees of 0.05, 0.06, and 0.07 MPa. The vacuum pump was then turned on continuously for 4 hours, and the changes in the evaporation temperature of the raw material solution were as follows: Figure 1 As shown. By Figure 1 It can be seen that after the water temperature in the evaporation and concentration tank reaches its boiling point, the liquid undergoes slow boiling, followed by fluctuations. The fluctuations are not significant at a vacuum of 0.05 MPa, but become more pronounced at a vacuum of 0.07 MPa. This is because after the vacuum pump is turned on at 55℃, the boiling point at 0.07 MPa is relatively low. As the heat pump continuously inputs heat, the boiling point is quickly reached. Once boiling, the water in the tank experiences superheating due to the continuous heating by the heat pump. This superheating leads to a sudden and violent boiling, absorbing a large amount of heat. This results in insufficient heating from the heat pump working fluid, causing the water to absorb its own internal heat, causing the water temperature to drop. After the violent boiling ends, the water temperature reaches the lowest value under that pressure, but does not boil. Subsequently, with the continued supply of heat from the heat pump, the water temperature gradually rises, and violent boiling occurs again. Therefore, it can be concluded that as the vacuum level inside the tank increases, the superheat of the water in the tank increases, so the higher the vacuum level, the more prone the water temperature is to fluctuations.

[0058] S2: As Figure 6 It can be seen that the increase or decrease in heat exchange can be determined by adjusting the vacuum level and the rise and fall of the evaporation temperature. Figure 5 In the diagram, 1 represents 0.05 MPa; 2 represents 0.06 MPa; and 3 represents 0.07 MPa. During the experiment, water temperature fluctuations caused the heat exchanger's temperature difference to not remain constant, and the amount of heat exchanged also fluctuated with the water temperature. Significant changes in ambient temperature before and after heat exchange affected the evaporation of the heat pump's working fluid. Therefore, instantaneous heat exchange was used for data analysis of the heat exchange temperature difference. Figure 2 It can be seen that under a vacuum of 0.05 MPa and an evaporation temperature of 75°C, the temperature of the steam generated during the evaporation of the raw material liquid increases, and the temperature difference between air and steam in the heat exchanger is relatively large, reaching 36°C. Under a vacuum of 0.07 MPa, the evaporation temperature decreases, and the heat exchange temperature difference decreases. Through the heat exchanger, the heat exchange capacity can reach 10 kW after heat exchange between steam and air, and the effect is more obvious when the vacuum decreases and the evaporation temperature increases. Therefore, the heat exchange capacity increases with the decrease of vacuum and the increase of evaporation temperature. The increase in heat exchange temperature difference and heat exchange capacity, as well as the improvement of the heat exchanger's heat exchange performance, fully demonstrate that the experimental equipment can recover and utilize the steam generated during the boiling of the material in the evaporation and concentration tank.

[0059] S3: By Figure 7It can be seen that the relationship between changes in vacuum degree and system energy consumption and heating capacity is as follows: as the vacuum degree increases and the evaporation temperature of the raw material liquid decreases, the system energy consumption gradually decreases, while the system heating capacity increases. Figure 7 In the diagram, 1 represents power consumption and 2 represents heating capacity. The system's power consumption decreased from 3.6 kW at a vacuum of 0.05 MPa to 2.87 kW at a vacuum of 0.07 MPa. The main reasons for this change in power consumption are twofold: firstly, the evaporation temperature of the feed liquid decreases as the vacuum increases, resulting in less compressor power consumption and reduced compressor energy consumption; secondly, the temperature in the evaporation and concentration tank gradually increases over time. At a vacuum of 0.05 MPa, the evaporation temperature of the feed liquid in the tank is the highest, leading to increasingly higher water temperatures in the heat exchanger within the evaporation tank. This, in turn, causes a gradual increase in condensation temperature and pressure, a larger suction and discharge pressure difference, and a higher pressure ratio, resulting in higher power consumption for the equipment at this point.

[0060] The system's heating capacity increases with increasing vacuum and decreasing feed liquid evaporation temperature. This is because at high vacuum, the evaporation temperature of water decreases, and the feed liquid evaporation temperature also decreases. As heating time progresses, the increasing temperature difference between the system's exhaust temperature and the hot water enhances heat exchange. Simultaneously, with a constant water volume in the evaporator, increasing vacuum and decreasing feed liquid evaporation temperature leads to a decrease in the working fluid condensation temperature, reducing the compressor's suction specific volume while the compressor's theoretical delivery volume remains constant. This results in an increase in the refrigerant volumetric flow rate entering the compressor. This increased refrigerant circulation leads to an increase in heating capacity.

[0061] S4: As Figure 8 It can be seen that by adjusting the vacuum level to change the COP and evaporation rate, the performance parameters of a heat pump, represented by the heat pump energy efficiency ratio (COP), are determined by the system's heating capacity and compressor energy consumption. From Figure 8 It can be seen that as the vacuum level increases, the COP gradually increases. For the coefficient of performance COP, when the evaporation temperature decreases, the heating capacity increases, while the power consumption of the compressor increases. Therefore, the COP value decreases as the temperature of the raw material liquid in the evaporator increases. Increasing the vacuum level can effectively increase the COP and evaporation rate of the equipment.

[0062] S5: As Figure 9-12 It can be seen that the ambient temperature is the indoor temperature under different weather conditions, and the vacuum degree is maintained at 0.07MPa, which shows the impact of ambient temperature on system performance. Figure 9 and Figure 10 In the diagram, 1 represents 0℃, 2 represents 10℃, and 3 represents 20℃. Figure 11 In the diagram, 1 represents power consumption and 2 represents heating capacity.

[0063] Depend on Figure 9-12It can be seen that by adjusting the rise and fall of ambient temperature, the compressor's discharge temperature, system energy consumption, heating capacity, evaporation rate, and COP can be determined; by adjusting vacuum degree, feed liquid evaporation temperature, heat exchange performance, and fan temperature, air temperature and steam utilization rate can be changed. With increasing ambient temperature, the compressor's discharge temperature, system energy consumption, heating capacity, evaporation rate, and COP all increase. At an ambient temperature of 20℃, the heat pump's performance improves. At this ambient temperature, the water in the tank begins to boil in a shorter time compared to when the ambient temperature is 0℃. After boiling, the higher ambient temperature leads to a larger heat exchange temperature difference, increasing the heat exchanger's heat exchange performance and causing the evaporation temperature of the heat pump working fluid to rise, resulting in increased compressor discharge temperature, heating capacity, and energy consumption. The main reason for these experimental results is that as the working fluid evaporation temperature increases, the corresponding evaporation pressure and condensation pressure also increase. This leads to an increase in the compressor discharge temperature, increasing the unit enthalpy difference of the heat pump working fluid at the condenser outlet. Simultaneously, while the theoretical discharge capacity of the compressor is constant, as the evaporation temperature rises, the compressor suction specific volume increases, and the mass flow rate of the working fluid increases. Therefore, the system's power consumption and heating capacity increase with increasing ambient temperature. The system's heating capacity increased from 9.7 kW at 0°C to 17.7 kW at 20°C, an increase of 83%. The heat pump system's COP increased from 3.39 to 5.38 with increasing ambient temperature, resulting in an increased evaporation rate, rising from 9.70 kg / h to 17.71 kg / h. These results are largely consistent with the effects of increased evaporation temperature on the system under different vacuum levels, demonstrating that increased evaporation temperature has a significant impact on heat pump performance.

[0064] In summary, as the vacuum level decreases, the evaporation temperature of the feed liquid in the evaporation and concentration tank increases. The heat exchanger's heat exchange performance also increases with the evaporation temperature of the feed liquid, reaching a maximum heat exchange temperature of 36℃ and a heat exchange capacity of 10kW. The increase in ambient temperature and the decrease in vacuum level result in a significant heat exchange effect. The temperature of the air entering the heat exchanger increases, and the steam recovery and utilization rate is significantly improved.

[0065] The system's power consumption decreases as the vacuum level increases, while the system's heating capacity increases, with power consumption decreasing from 3.6 kW to 2.87 kW. As the ambient temperature rises, both heating capacity and power consumption increase, with the heating capacity increasing significantly, rising from 9.7 kW at 0°C to 17.7 kW at 20°C, an increase of 83%.

[0066] The COP and evaporation rate increase with increasing vacuum level and ambient temperature. The COP of this system increased from a minimum of 3.39 to 6.00, and the evaporation rate increased to 22.0 kg / h. After steam recovery and utilization, the heat pump efficiency and evaporation rate after heat exchange are significantly improved.

[0067] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A low-temperature evaporation and concentration system based on a solar phase change energy storage heat pump, characterized in that: include, The heat storage unit (100) includes a PVT solar collector (101), a solenoid valve (102), and a phase change energy storage box (103). The solenoid valve (102) is connected to the phase change energy storage box (103) on one side and to the PVT solar collector (101) on the other side. The PVT solar collector (101) includes a flat glass (101a), a photovoltaic cell (101b), a polyvinyl fluoride composite film and thermally conductive adhesive (101c), a heat absorber plate (101d), an insulation layer (101e), and a heat collection tube (101f). The bottom of the flat glass (101a) is connected to the photovoltaic cell (101b). The bottom of the polyvinyl fluoride composite film and thermally conductive adhesive (101c) is connected to the heat absorber plate (101d). The insulation layer (101e) is located at the bottom of the heat absorber plate (101d), and the heat collection tube (101f) is located inside the insulation layer (101e). The heat pump unit (200) includes an air-cooled finned evaporator (201), a compressor (202), a four-way valve (203), a phase change energy storage tank (103), and a throttling valve (204). The air-cooled finned evaporator (201) is connected to the four-way valve (203) on one side and to the throttling valve (204) on the other side. The compressor (202) is connected to the four-way valve (203) on one side and to the phase change energy storage tank (103) on the other side. An evaporation and concentration unit (300) includes an evaporation and concentration tank (301), an insulation layer (302), a stirrer (303), a vacuum gauge (304), a defoaming component (305), a stirring blade (306), a heating coil (307), a water pump (308), a raw material tank (309), and a concentrate tank (310). The stirrer (303) is connected to one side of the evaporation and concentration tank (301). The vacuum gauge (304) is located on one side of the evaporation and concentration tank (301). The insulation layer (302) is located on the inner wall of the evaporation and concentration tank (301). The defoaming component (305) is located inside the evaporation and concentration tank (301). The output end of the stirrer (303) extends into the evaporation and concentration tank (301). The stirring blade (306) is wound around the output end of the stirrer (303). The vacuum unit (400) includes an expansion valve (401), a heat exchanger (402), a vacuum jet injector (403), a water tank (404), a porous tube (405), and a vacuum circulation pump (406). The heat exchanger (402) is connected to the expansion valve (401) on one side and to the vacuum jet injector (403) on the other side. The water tank (404) is connected to the vacuum circulation pump (406) on one side and to the vacuum jet injector (403) on the other side. The porous tube (405) is located inside the water tank (404).

2. The low-temperature evaporation and concentration system based on a solar phase change energy storage heat pump as described in claim 1, characterized in that: The phase change energy storage box (103) includes a box body (103a), a constant temperature layer (103b), a heat exchange coil (103c), a refrigerant (103d), a filter box (103e), a phase change heat storage ball (103f), and a fixing buckle (103g). The constant temperature layer (103b) is located inside the box body (103a), the heat exchange coil (103c) is located inside the box body (103a), the refrigerant (103d) is wrapped around the outside of the heat exchange coil (103c), the phase change heat storage ball (103f) is located inside the filter box (103e), and the fixing buckle (103g) is located on the top of the filter box (103e).

3. A low-temperature evaporation and concentration method based on a solar phase change energy storage heat pump, characterized in that: Including the low-temperature evaporation and concentration system based on a solar phase change energy storage heat pump as described in any one of claims 1 to 2, and, By reducing the vacuum level, the efficiency of the heat exchanger (402) and the steam recovery rate are improved; By increasing the vacuum level and reducing energy consumption, the heating capacity is increased while the power consumption is decreased. By increasing the vacuum level and temperature, the COP (Coefficient of Performance) and evaporation rate of the heat pump can be improved.

4. The low-temperature evaporation and concentration method based on a solar phase change energy storage heat pump as described in claim 3, characterized in that: The change in heat exchange is determined by adjusting the vacuum level and the rise and fall of the evaporation temperature; The raw material liquid is heated, the vacuum level of the evaporation and concentration tank is controlled, and the vacuum level of the vacuum pump is increased.

5. The low-temperature evaporation and concentration method based on a solar phase change energy storage heat pump as described in claim 4, characterized in that: The energy consumption of the compressor can be determined by adjusting the vacuum level and the evaporation temperature of the raw material liquid.

6. The low-temperature evaporation and concentration method based on a solar phase change energy storage heat pump as described in claim 5, characterized in that: The COP and evaporation rate can be changed by adjusting the vacuum level; By adjusting the rise and fall of ambient temperature, the compressor's exhaust temperature, system energy consumption, heating capacity, evaporation rate, and COP can be determined.

7. The low-temperature evaporation and concentration method based on a solar phase change energy storage heat pump as described in claim 6, characterized in that: By adjusting the vacuum level, the evaporation temperature of the raw liquid, the heat exchange performance, and the fan temperature, the air temperature and steam utilization rate can be changed.

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