An improved system for vacuum anti-corrosion and anti-leakage heat pump water storage tank

Abstract

The invention discloses an improved system for a vacuum anti-corrosion and anti-leakage heat pump water storage tank, belonging to the technical field of heat pump water heaters; the system comprises a vacuum water storage tank and a heat pump control method, the vacuum water storage tank comprises an outer shell, an inner tank and a vacuum cover, a cavity is formed between the outer shell and the inner tank, a plurality of microchannels are evenly distributed circumferentially on the outer wall of the inner tank, the vacuum cover is placed in the cavity and covers the outer wall of the inner tank and the plurality of microchannels to form a closed vacuum zone; the heat preservation can be performed and the microchannels can be effectively prevented from being corroded by external water vapor; the heat pump control method comprises the steps of initial vacuum degree detection, vacuum degree adjustment, continuous monitoring of the vacuum degree under normal heating state and vacuum degree abnormality detection; specifically, the system monitors and adjusts the closed vacuum zone pressure value of the vacuum water storage tank in real time, combines a mathematical model based on experimental data regression fitting of the vacuum degree of the closed vacuum zone and the heat preservation effect of the water storage tank, and accurately controls the vacuum degree to achieve the optimal heat preservation effect.

Description

Technical Field

[0001] The invention relates to the technical field of heat pump water heaters, and in particular to an improved system for a vacuum anti-corrosion and anti-leakage heat pump water storage tank. Background Art

[0002] In the current household heat pump water heater market, the design of traditional water storage tanks is gradually tending to adopt aluminum microchannel heat exchangers and polyurethane foam insulation layers to improve heat exchange efficiency and thermal insulation performance. However, this design exposed a series of problems during its application: First, when the aluminum microchannel heat exchanger is installed on the iron inner wall, it is easy to cause electrochemical corrosion due to the physical potential difference between different metals; during the heating process of the heat pump water heater, hot and humid air is easy to condense into water droplets on the surface of the aluminum microchannel. The chloride ions dissolved in these water droplets will accelerate the corrosion of the microchannel, which will lead to leakage problems in the entire system, seriously affecting the service life of the water heater; secondly, the polyurethane foam insulation layer is a key component to improve the thermal insulation performance of the water heater. Its thickness often needs to reach more than 40mm to meet the national standard insulation requirements; therefore, this thickness requirement greatly increases the size of the entire unit and limits the flexibility of the water heater in space utilization; thirdly, the process of wrapping the aluminum microchannel around the condensation of the heat pump water heater is complicated and difficult to control. During the winding process, the surface of the microchannel is easily damaged by scratches and bending, and its anti-corrosion layer is accelerated after encountering water, resulting in refrigerant leakage, making the system unable to operate normally and difficult to repair.

[0003] In response to this problem, Chinese invention patent CN109269100A discloses a highly efficient heat pump insulation system, which forms a closed cavity by configuring the outer shell and the inner tank into a double-layer structure, and at the same time provides a vacuum tube connected to the cavity, so as to maintain the vacuum degree of the closed cavity under the vacuum pump, thereby achieving the purpose of thermal insulation and avoiding corrosion of the insulation layer; however, although the invention effectively improves the thermal insulation performance of the insulation system and reduces the risk of environmental erosion of the insulation layer through the innovative double-layer water tank structure and vacuum cavity design, it does not provide a detailed description of the quantitative relationship between the vacuum degree inside the cavity and the insulation effect of the system, but the optimization of this key parameter plays an important role in further improving the insulation efficiency, reducing energy consumption and ensuring the long-term stable operation of the system. Summary of the invention

[0004] The purpose of the present invention is to provide an improved vacuum corrosion-proof and leak-proof heat pump water storage tank system to solve the problem of the prior art raised in the above background technology regarding the quantitative correlation relationship between the vacuum degree inside the cavity and the thermal insulation effect of the system.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system comprises a vacuum water storage tank and a heat pump control system, wherein the vacuum water storage tank comprises an outer shell, an inner shell and a vacuum cover, a cavity is formed between the outer shell and the inner shell, a plurality of microchannels are uniformly distributed in an annular direction on the outer wall of the inner shell, a same starting point of a plurality of the microchannels are connected to a first main pipe arranged vertically, a same end point of a plurality of the microchannels are connected to a second main pipe arranged vertically, the microchannels and the first main pipe and the second main pipe constitute a condenser, the first main pipe and the second main pipe are parallel to each other and fixed on the outer wall of the inner shell, the first main pipe is connected to a refrigerant inlet pipe, and the second main pipe is connected to a refrigerant outlet pipe; the vacuum cover is placed in the cavity and covers the outer wall of the inner shell and a plurality of the microchannels to form a closed vacuum area, a vacuum port is provided on the top of the vacuum cover, and the vacuum port is connected to the closed vacuum area;

[0007] The heat pump control system includes a refrigerant circulation flow path, which includes a compressor, a throttling device, an evaporator and a condenser. The inlet and outlet of the refrigerant circulation flow path are respectively connected to the refrigerant outlet pipe and the refrigerant inlet pipe, and the refrigerant outlet pipe, the throttling device, the evaporator and the compressor of the vacuum water storage tank are connected to the refrigerant outlet pipe in sequence, and the refrigerant circulation flow path is formed with the condenser. The return air port of the compressor is connected to the vacuum port of the vacuum water storage tank through a negative pressure return air pipe. A pressure sensor is provided near the vacuum port to detect the vacuum degree of the enclosed vacuum area. A first solenoid valve that is controlled to open when the water tank is evacuated is provided on the negative pressure return air pipe. A second solenoid valve that is controlled to close when the water tank is evacuated is provided between the outlet of the evaporator and the return air port of the compressor.

[0008] Since the heat preservation effect of the hot water storage tank is closely related to the vacuum degree of the closed vacuum zone, the pressure value of the closed vacuum zone is set to P, the temperature decay value of the hot water storage tank is ΔT, the surface area of ​​the hot water storage tank is s, the volume of the hot water storage tank is v, the heat preservation time of the hot water storage tank is t, the thermal conductivity of the water tank as a whole is λ, and the ambient temperature is t a; These factors jointly affect the temperature decay value ΔT of the water in the hot water storage tank by affecting the heat exchange process between the hot water storage tank and the environment and the heat storage capacity of the hot water storage tank itself; Generally speaking, the smaller the pressure value P of the closed vacuum zone, the greater the vacuum degree, the less heat loss caused by heat conduction and radiation through the container wall, and the better the insulation effect; Specifically: the surface area to volume ratio S / V of the hot water storage tank directly affects its heat exchange efficiency with the surrounding environment. The larger the S / V, the greater the heat loss through radiation and convection, and the worse the insulation effect; The insulation time t of the hot water storage tank is the duration of the heat transfer and storage process. Under given conditions, the larger t is, the more sufficient the heat exchange between the hot water storage tank and the environment is, and the insulation effect is reduced accordingly; The thermal conductivity λ is a physical quantity that measures the thermal conductivity of a material. For a hot water storage tank, the λ value of its shell material mainly determines the rate at which heat is lost to the environment through the tank wall. The larger the λ value, the faster the heat loss and the worse the insulation effect; The ambient temperature t a It is the reference point for heat loss in the water tank. When the water temperature in the hot water storage tank is higher than t a When t a The greater the difference between the initial temperature of the water in the hot water storage tank, the worse the insulation effect;

[0009] After a large number of experiments, it was found that when the above conditions are certain, the thermal insulation effect of the hot water storage tank is also closely related to the pressure change in the closed vacuum zone. The correlation characteristics can be mainly divided into the following two stages: In the first stage, the air pressure in the closed vacuum zone gradually decreases from the approximate value of the standard atmospheric pressure (about 100,000 Pa) to 2000 Pa. In this process, as the air pressure decreases, that is, the vacuum degree continues to increase, the thermal insulation effect is rapidly enhanced; specifically, as time goes by, the cavity begins to discharge a large amount of air, the air pressure drops rapidly, the thermal insulation performance of the hot water storage tank is significantly enhanced, and the temperature drop rate is significantly slowed down; this is because as the air pressure drops, the air in the cavity is gradually drawn out, resulting in the weakening of heat conduction and convection, thereby continuously slowing down the rate of temperature loss inside the water tank; in the second stage, the air pressure in the vacuum zone continues to drop from 2000 Pa to a lower level, until about 200Pa; in this stage, the change of thermal insulation effect presents different characteristics from the first stage; when the air pressure drops from the beginning to 2000Pa, the air pressure gradually decreases with the increase of the vacuum degree in the cavity, and the thermal insulation effect is significantly enhanced; however, in the process of the air pressure dropping from 2000Pa to 200Pa, although the air pressure in the cavity is still decreasing, the thermal insulation effect does not change significantly. This is mainly because, when the cavity air pressure drops to a lower level (2000Pa), the thermal insulation performance of the hot water storage tank cavity is close to the limit, but the heat conduction of other connectors inside the water tank structure becomes the main heat dissipation path, and the influence of its heat dissipation on the dissipation of hot water temperature covers the influence of the change of cavity vacuum degree; therefore, in the second stage, even if the vacuum degree is further increased, the thermal insulation effect does not change significantly.

[0010] Therefore, when discussing the influence of the above factors on ΔT, especially when discussing the relationship between the temperature attenuation value ΔT of the hot water storage tank and the pressure value P of the closed vacuum area, the changes in the influence rules between the first stage and the second stage and their causes are the research focus of the present invention. Therefore, the subsequent quantitative relationship research is mainly concentrated near the inflection point of the change between the first stage and the second stage.

[0011] According to the influence of the above factors on ΔT, the relationship between the temperature attenuation value ΔT of the hot water storage tank and the pressure value P of the closed vacuum area is regressed and fitted to meet the following formula:

[0012]

[0013] In formula (1), P is the pressure value of the closed vacuum zone (select the air pressure range of 200-6000 Pa), ΔT is the temperature attenuation value of the hot water storage tank, S is the surface area of ​​the hot water storage tank, v is the volume of the hot water storage tank, t is the insulation time of the hot water storage tank, λ is the thermal conductivity of the water tank, t a -Ambient temperature, a, b, c are adjustment coefficients.

[0014] Specifically, a third solenoid valve is provided between the exhaust port of the compressor and the air inlet of the evaporator. When it is detected that the water tank is vacuumed or the evaporator needs to be defrosted, the heat pump control system controls the third solenoid valve to open.

[0015] Specifically, a water inlet and a water outlet are provided on the inner tank, the water inlet is connected to a cold water supply pipe, and the water outlet is connected to a user's hot water supply pipe.

[0016] Furthermore, the vacuum water storage tank also includes a first temperature sensor and a second temperature sensor, wherein the first temperature sensor is arranged on the user's hot water supply pipe to monitor the outlet water temperature T1, and the second temperature sensor is arranged on the cold water supply pipe to monitor the inlet water temperature T2.

[0017] Specifically, one end of the refrigerant inlet pipe connected to the first main pipe is a fluorine circuit inlet, and one end of the refrigerant outlet pipe connected to the second main pipe is a fluorine circuit outlet.

[0018] Preferably, a dense rubber coating layer is provided at the connection between the vacuum cover and the outer wall of the inner container.

[0019] Preferably, the contact surfaces between the inner tank and the plurality of microchannels are coated with a thermally conductive silicone grease coating.

[0020] The control method of the vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system comprises the following steps:

[0021] S1. Initial vacuum degree detection: Based on the regression fitting formula (1) of the temperature attenuation value of the hot water storage tank and the pressure value of the sealed vacuum area, preset the vacuum degree threshold as Z to ensure the maximization of the heat preservation effect; after the improved system of the vacuum anti-corrosion and leak-proof heat pump hot water storage tank is powered on for the first time, read the measured vacuum degree value Z1 of the current air pressure sensor and compare it with the vacuum degree threshold Z;

[0022] S2. Vacuum degree adjustment: If it is detected that Z1>Z, that is, the vacuum degree is insufficient, start the vacuum pumping process, and the steps are as follows:

[0023] a. Immediately open the first solenoid valve and the third solenoid valve; close the second solenoid valve to block other non-air extraction paths;

[0024] b. Start the compressor to start extracting the air in the vacuum chamber to reduce its internal pressure;

[0025] c. Continuously monitor the measured vacuum degree value Z1 of the air pressure sensor until Z1<Z - 50Pa to ensure that it reaches and is slightly lower than the optimal vacuum degree range;

[0026] d. After the vacuum degree reaches Z - 50Pa, stop the operation of the compressor and close the first solenoid valve and the third solenoid valve to exit the vacuum pumping process;

[0027] e. The system components switch to the normal heating state and are ready to start the hot water heating cycle;

[0028] S3. Continuous monitoring of the vacuum degree in the normal heating state: In the normal heating state, continuously monitor the inlet water temperature T1, the outlet water temperature T2 and the measured vacuum degree value Z1 of the vacuum hot water storage tank to ensure that they fluctuate within the set range; and ensure that the first solenoid valve and the third solenoid valve are in the closed state in the heating state to prevent unnecessary gas exchange from affecting the vacuum degree;

[0029] S4. Abnormal vacuum degree detection: If the measured vacuum degree value Z1 of the air pressure sensor is ≥Z + 50Pa within 10 consecutive seconds, it is determined that the vacuum degree is abnormal and needs to be vacuumed again, and continue to perform step S2 and step S3.

[0030] Specifically, in step S4, before it is determined that re-vacuuming is required, start the heat pump unit to run for 5 - 8 minutes; to increase the system temperature and pressure, prepare for the subsequent vacuum pumping operation, and at the same time help to remove some residual moisture and impurities in the system.

[0031] In summary, compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. By setting a vacuum cover between the inner tank and the outer shell, the vacuum cover is placed in the cavity formed by the inner tank and the outer shell and covers the outer wall of the inner tank and several microchannels to form a closed vacuum zone. The vacuum environment, as a poor conductor of heat, greatly reduces the heat conduction and heat convection losses, and achieves efficient heat insulation. Compared with traditional thermal insulation cotton, this heat insulation method does not need to rely on the thickness and density of the material to accumulate the heat insulation effect, but fundamentally blocks the heat transfer path. At the same time, the vacuum environment effectively isolates air and moisture, and can also effectively prevent the inner tank and microchannels from being corroded by external corrosive substances, thereby extending the service life of the water tank; in addition, by accurately fitting the functional relationship between the temperature attenuation value of the hot water storage tank and the pressure value of the closed vacuum zone, it provides clear guidance for the design and manufacturing process to optimize the pressure of the vacuum zone to the optimal value, thereby effectively reducing the heat loss inside the water tank and improving the heat preservation effect; this functional relationship can also calculate the balance point between the heat preservation effect and energy consumption under different vacuum degrees, so as to minimize energy consumption while ensuring sufficient heat preservation effect, improve the system energy efficiency ratio, and effectively reduce operating costs.

[0033] 2. The system is equipped with an air pressure sensor and corresponding control logic. By accurately controlling the operation of the heat pump unit and the maintenance of the vacuum degree, it can ensure the supply of hot water while monitoring the vacuum degree in real time and automatically adjust it as needed. This not only ensures that users always have a stable and comfortable supply of hot water, but also ensures the long-term and efficient operation of the system, and avoids the decrease in thermal efficiency due to insufficient vacuum.

[0034] 3. Through experiments and data analysis, it is found that when the pressure value of the closed vacuum zone is maintained at about 2000pa, the thermal insulation effect of the water storage tank can reach the optimal state. The built-in compressor of the system can accurately adjust the pressure of the vacuum zone to this ideal range during the vacuum operation, thus eliminating the need for additional vacuum pump equipment, simplifying the system structure, and reducing the overall equipment cost and energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the structure of the inner tank of the vacuum water storage tank of the present invention;

[0036] Figure 2 It is a schematic diagram of the vacuum water storage tank system of the present invention;

[0037] Figure 3 for Figure 1 A partial enlarged view of the section A of the vacuum water storage tank;

[0038] Figure 4 This is a flow chart of the vacuum water storage tank control method of the present invention;

[0039] Figure 5 This is a control system diagram of the heat pump system of the present invention;

[0040] Figure 6 It is a functional relationship diagram of the temperature attenuation value of the hot water storage tank of the present invention and the pressure value of the closed vacuum area;

[0041] In the figure: 1- liner, 2- microchannel, 3- vacuum cover, 4- shell, 5- air pressure sensor, 6- condenser, 7- cavity, 8- closed vacuum area, 9- compressor, 10- throttling device, 11- evaporator, 12- first solenoid valve, 13- second solenoid valve, 14- third solenoid valve, 15- first temperature sensor, 16- second temperature sensor, 17- water inlet, 18- water outlet, 19- fluorine inlet, 20- fluorine outlet, 21- vacuum port, 22- first main pipe, 23- second main pipe. DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments given here are only used to illustrate and explain the present invention, and cannot be used to limit the present invention.

[0043] It should be noted that many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention may also have other implementation modes. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0044] By the attached Figure 1-3 As shown, an improved system for a vacuum anti-corrosion and anti-leakage heat pump water storage tank comprises a vacuum water storage tank and a heat pump control system, wherein the vacuum water storage tank comprises an outer shell 4, an inner tank 1 and a vacuum cover 3, a cavity 7 is formed between the outer shell 4 and the inner tank 1, a plurality of microchannels 2 are uniformly distributed in an annular direction on the outer wall of the inner tank 1, the same starting point of the plurality of microchannels 2 are all connected to a first main pipe 22 arranged vertically, and the same end point of the plurality of microchannels 2 are all connected to a second main pipe 23 arranged vertically, the microchannels and the first main pipe 22 and the second main pipe 23 constitute a condenser 6, the first main pipe 22 and the second main pipe 23 are parallel to each other and fixed on the outer wall of the inner tank 1, the first main pipe 22 is connected to a refrigerant inlet pipe, and the second main pipe 3 is connected to a refrigerant outlet pipe; the vacuum cover 3 is placed in the cavity 7 and covers the outer wall of the inner tank 1 and the plurality of microchannels 2 to form a closed vacuum area 8, the top of the vacuum cover 3 is provided with a vacuum port 21, and the vacuum port 21 is connected to the closed vacuum area 8;

[0045] As attached Figure 5As shown, the heat pump control system includes a refrigerant circulation flow path, and the refrigerant circulation flow path includes a compressor 9, a throttling device 10, an evaporator 11 and a condenser 6. The inlet and outlet of the refrigerant circulation flow path are respectively connected to the refrigerant outlet pipe and the refrigerant inlet pipe, and the refrigerant outlet pipe, the throttling device 10, the evaporator 11, and the compressor 9 of the vacuum water storage tank are connected to the refrigerant outlet pipe in sequence, and the refrigerant circulation flow path is formed with the condenser 6. The return air port of the compressor 9 is connected to the vacuum port 21 of the vacuum water storage tank through a negative pressure return air pipe. A pressure sensor 5 is provided near the vacuum port 21 for detecting the vacuum degree of the pressure sensor 8. A first solenoid valve 12 that is controlled to open when the water tank is evacuated is provided on the negative pressure return air pipeline. A second solenoid valve 13 that is controlled to close when the water tank is evacuated is provided between the outlet of the evaporator 11 and the return air port of the compressor 9.

[0046] Since the thermal insulation effect of the hot water storage tank is closely related to the closed vacuum zone, the pressure value of the closed vacuum zone is set to P, the temperature attenuation value of the hot water storage tank is ΔT, the surface area of ​​the hot water storage tank is s, the volume of the hot water storage tank is v, the thermal insulation time of the hot water storage tank is t, the thermal conductivity of the water tank is λ, and the ambient temperature is t a According to the data relationship between the temperature attenuation value ΔT of the hot water storage tank and the pressure value P of the closed vacuum area, the relationship between the temperature attenuation value ΔT of the hot water storage tank and the pressure value P of the closed vacuum area is regressed and fitted to meet the following formula:

[0047]

[0048] In formula (1), P is the pressure value of the closed vacuum zone, ΔT is the temperature attenuation value of the water storage tank, S is the surface area of ​​the water storage tank, v is the volume of the water storage tank, t is the insulation time of the water storage tank, λ is the thermal conductivity of the water tank, and t is the a -Ambient temperature, a, b, c are adjustment coefficients;

[0049] In this specific embodiment, the surface area of ​​the hot water storage tank is 3 m2 and the volume of the hot water storage tank is 0.25 m 3 , the heat preservation time of the hot water storage tank is 6 hours, the thermal conductivity of the water tank is 16.2W / (m·K), and the ambient temperature is 20℃; the corresponding relationship between the pressure value of the closed vacuum area and the temperature attenuation value of the water tank is recorded in detail in Table 1 below:

[0050] P(pa) ΔT(℃) 6000 6.7 5000 6.0 4000 4.9 3000 3.9 2500 3.5 2000 3.0 1800 3.0 1600 2.9 1400 2.9 1200 2.9 1000 2.8 800 2.8 600 2.8 400 2.8 200 2.8

[0051] The above formula can be used to guide the design and optimization of hot water storage tanks to reduce heat loss and improve energy efficiency.

[0052] Specifically, a third solenoid valve 14 is provided between the exhaust port of the compressor 9 and the air inlet of the evaporator 11. When it is detected that the water tank is vacuumed or the evaporator 11 needs to be defrosted, the heat pump control system controls the third solenoid valve 14 to open.

[0053] Specifically, the inner tank 1 is provided with a water inlet 17 and a water outlet 18, the water inlet 17 is connected to a cold water supply pipe, and the water outlet 18 is connected to a user's hot water supply pipe.

[0054] Furthermore, the vacuum water storage tank also includes a first temperature sensor 15 and a second temperature sensor 16. The first temperature sensor 15 is arranged on the user's hot water supply pipe to monitor the outlet water temperature T1, and the second temperature sensor 16 is arranged on the cold water supply pipe to monitor the inlet water temperature T2.

[0055] Specifically, one end of the refrigerant inlet pipe connected to the first main pipe 22 is a fluorine circuit inlet 19 , and one end of the refrigerant outlet pipe connected to the second main pipe 23 is a fluorine circuit outlet 20 .

[0056] Specifically, a dense rubber coating layer is provided at the connection between the vacuum cover 3 and the outer wall of the inner container 1.

[0057] Specifically, the contact surfaces between the inner tank 1 and the plurality of microchannels 2 are coated with a thermally conductive silicone grease coating.

[0058] As attached Figure 4 As shown, the control method of the vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system comprises the following steps:

[0059] S1. Initial vacuum detection: Based on the regression fitting formula (1) of the temperature attenuation value of the hot water storage tank and the pressure value of the closed vacuum area, the vacuum threshold value Z is preset to ensure the maximum insulation effect; after the vacuum corrosion and leakage-proof heat pump hot water storage tank improvement system is powered on for the first time, the vacuum value Z1 of the current air pressure sensor 5 is read and compared with the vacuum threshold value Z; in this embodiment, the vacuum threshold value Z is preset to be 2000pa;

[0060] S2. Vacuum adjustment: If it is detected that Z1>Z, that is, the vacuum is insufficient, the vacuum process is started and the execution steps are as follows:

[0061] a. Immediately open the first solenoid valve 12 and the third solenoid valve 14 to ensure that the air extraction path is unobstructed; close the second solenoid valve 13 to block other non-air extraction paths;

[0062] b. Start the compressor 9 to start extracting the air in the vacuum cover 3;

[0063] c. Continuously monitor the measured vacuum value Z1 of the pressure sensor 5 until Z1 < Z - 50 Pa to ensure there is sufficient vacuum margin;

[0064] d. After the vacuum reaches Z - 50 Pa, stop the operation of the compressor 9, and close the first solenoid valve 12 and the third solenoid valve 14 to exit the vacuum pumping process;

[0065] e. The system components switch to the normal heating state and are ready to start the hot water heating cycle;

[0066] S3. Continuous monitoring of the vacuum degree in the normal heating state: In the normal heating state, continuously monitor the inlet water temperature T1, the outlet water temperature T2, and the measured vacuum value Z1 of the vacuum storage water tank to ensure that they fluctuate within the set range; and ensure that the first solenoid valve 12 and the third solenoid valve 14 are in the closed state during the heating state to prevent unnecessary energy loss and safety hazards;

[0067] S4. Abnormal vacuum degree detection: If the measured vacuum value Z1 of the pressure sensor 5 is ≥ Z + 50 Pa within 10 consecutive seconds, it is determined that the vacuum degree is abnormal and re - vacuum pumping is required. Then continue with steps S2 and S3.

[0068] Specifically, in step S4, before determining that re - vacuum pumping is required, start the heat pump unit to operate for 5 - 8 minutes; to increase the system temperature and pressure, prepare for the subsequent vacuum pumping operation, and at the same time help remove some residual moisture and impurities in the system.

[0069] 1. Working process of the heat pump water heater for heating water:

[0070] In the hot water heating mode, initial state: The first solenoid valve 12 and the third solenoid valve 14 are closed, and the second solenoid valve 13 is open; the compressor 9 is not started, and the refrigerant is in a static state in the system; the water temperature in the vacuum storage water tank is monitored and recorded by the temperature sensor.

[0071] When the user needs to use hot water, the system receives a heating instruction, and the compressor 9 starts. It sucks in the low-temperature and low-pressure refrigerant gas from the evaporator 11 by opening the second solenoid valve 13. The refrigerant gas is compressed into a high-temperature and high-pressure gas, and then discharged into the refrigerant outlet pipe. The high-temperature and high-pressure refrigerant gas enters through the fluorine inlet 19 of the microchannel 2. The microchannel 2 closely attached to the outer wall of the inner tank 1 serves as a heating belt, transferring heat to the water in the inner tank 1. After the water is heated, it flows out from the water outlet 18 for the user to use. The cooled refrigerant liquid flows back to the heat pump control system through the refrigerant outlet 20 of the microchannel 2. After being depressurized by the throttling device 10, it enters the evaporator 11 again to complete a heating cycle. The system adjusts the operating time and frequency of the compressor 9 by monitoring the outlet water temperature T1 and the inlet water temperature T2 to keep the water temperature within the set range.

[0072] 2. Working process of vacuum pumping for the heat pump water heater:

[0073] After the system is powered on, it reads the measured vacuum value Z1 of the current pressure sensor 5 and compares it with the vacuum threshold Z. If the vacuum is insufficient, it starts the vacuum pumping process, opens the first solenoid valve 12 and the third solenoid valve 14, and closes the second solenoid valve 13. The compressor 9 is started to pump the air in the vacuum hood 3. Continuously monitor the measured vacuum value Z1 of the pressure sensor 5 until Z1 < Z - 50 Pa. After the vacuum reaches Z - 50 Pa, stop the operation of the compressor 9 and close the first solenoid valve 12 and the third solenoid valve 14 to exit the vacuum pumping process and complete the vacuum pumping.

[0074] 3. Working process of defrosting for the heat pump water heater:

[0075] When the heat pump control system detects that the surface of the evaporator 11 is severely frosted, the system switches to the defrosting mode. At this time, the second solenoid valve 13 in the heating cycle is closed, and the third solenoid valve 14 is opened. The compressor 9 continues to operate, but at this time the refrigerant flow direction is adjusted, and the compressor 9 releases heat to the surface of the evaporator 11 to melt the frost layer. When the frost layer is completely melted, the heat pump control system switches back to the heating mode to continue heating the water in the water tank.

[0076] The above has described the embodiments of the present invention in detail in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principles and spirit of the present invention, various changes, modifications, substitutions, and variations made to these embodiments still fall within the protection scope of the present invention.

Claims

1. A vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system, characterized by: The invention comprises a vacuum heat storage tank and a heat pump control system, wherein the vacuum heat storage tank comprises an outer shell (4), an inner tank (1) and a vacuum cover (3), wherein a cavity (7) is formed between the outer shell (4) and the inner tank (1), and a plurality of microchannels (2) are evenly distributed in a circumferential direction on the outer wall of the inner tank (1), wherein the same starting point of the plurality of microchannels (2) is connected to a first main pipe (22) arranged vertically, and the same end point of the plurality of microchannels (2) is connected to a second main pipe (23) arranged vertically, and the microchannels are connected to the first main pipe (22) and the second main pipe. (23) constitutes a condenser (6), the first main pipe (22) and the second main pipe (23) are parallel to each other and fixed on the outer wall of the inner tank (1), the first main pipe (22) is connected to the refrigerant inlet pipe, and the second main pipe (23) is connected to the refrigerant outlet pipe; the vacuum cover (3) is placed in the cavity (7) and covers the outer wall of the inner tank (1) and the plurality of microchannels (2) to form a closed vacuum area (8), the top of the vacuum cover (3) is provided with a vacuum port (21), and the vacuum port (21) is connected to the closed vacuum area (8); The heat pump control system comprises a refrigerant circulation flow path, and the refrigerant circulation flow path comprises a compressor (9), a throttling device (10), an evaporator (11) and a condenser (6). The inlet and outlet of the refrigerant circulation flow path are respectively connected to the refrigerant outlet pipe and the refrigerant inlet pipe, and the refrigerant outlet pipe, the throttling device (10), the evaporator (11), the compressor (9) and the refrigerant inlet pipe of the vacuum water storage tank are connected in sequence, and the refrigerant circulation flow path is formed with the condenser (6). The return air port of the compressor (9) is connected to the vacuum port (21) of the vacuum water storage tank through a negative pressure return air pipe. A pressure sensor (5) is provided near the vacuum port (21) for detecting the vacuum degree of the pressure sensor (5). A first solenoid valve (12) is provided on the negative pressure return air pipe and is controlled to be opened when the water tank is evacuated. A second solenoid valve (13) is provided between the outlet of the evaporator (11) and the return air port of the compressor (9) and is controlled to be closed when the water tank is evacuated. Since the heat preservation effect of the hot water storage tank is closely related to the vacuum degree of the closed vacuum zone, the pressure value of the closed vacuum zone is set to P, the temperature decay value of the hot water storage tank is ΔT, the surface area of ​​the hot water storage tank is s, the volume of the hot water storage tank is v, the heat preservation time of the hot water storage tank is t, the thermal conductivity of the water tank is λ, and the ambient temperature is t a According to the data relationship between the temperature attenuation value ΔT of the hot water storage tank and the pressure value P of the closed vacuum area, the relationship between the temperature attenuation value ΔT of the hot water storage tank and the pressure value P of the closed vacuum area is regressed and fitted to meet the following formula: In formula (1), P is the pressure value of the closed vacuum zone, ΔT is the temperature attenuation value of the water storage tank, S is the surface area of ​​the water storage tank, v is the volume of the water storage tank, t is the insulation time of the water storage tank, λ is the thermal conductivity of the water tank, and t is the a -Ambient temperature, a, b, c are adjustment coefficients.

2. The vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system according to claim 1 is characterized by: A third solenoid valve (14) is provided between the exhaust port of the compressor (9) and the air inlet of the evaporator (11); when it is detected that the water tank is evacuated or the evaporator (11) needs to be defrosted, the heat pump control system controls the third solenoid valve (14) to open.

3. The vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system according to claim 1 is characterized by: The inner tank (1) is provided with a water inlet (17) and a water outlet (18), wherein the water inlet (17) is connected to a cold water supply pipe, and the water outlet (18) is connected to a user's hot water supply pipe.

4. The vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system according to claim 3 is characterized by: The vacuum water storage tank further comprises a first temperature sensor (15) and a second temperature sensor (16), wherein the first temperature sensor (15) is arranged on the user's hot water supply pipe to monitor the outlet water temperature T1, and the second temperature sensor (16) is arranged on the cold water supply pipe to monitor the inlet water temperature T2.

5. The vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system according to claim 1 is characterized by: One end of the refrigerant inlet pipe connected to the first main pipe (22) is a fluorine circuit inlet (19), and one end of the refrigerant outlet pipe connected to the second main pipe (23) is a fluorine circuit outlet (20).

6. The vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system according to claim 1 is characterized by: A dense glue coating layer is provided at the connection between the vacuum hood (3) and the outer wall of the inner tank (1).

7. The vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system according to claim 1 is characterized in that: A heat-conducting silicone grease coating is applied to the contact surface between the inner tank (1) and several of the micro-channels (2).

8. The control method of the vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system according to any one of claims 1 to 7, characterized in that: It includes the following steps: S1. Initial vacuum degree detection: Based on the regression fitting formula (1) of the temperature attenuation value of the hot water storage tank and the pressure value of the sealed vacuum area, a vacuum degree threshold Z is preset; after the improved system of the vacuum anti-corrosion and anti-leakage heat pump hot water storage tank is powered on for the first time, the measured vacuum degree value Z1 of the current air pressure sensor (5) is read and compared with the vacuum degree threshold Z. S2. Vacuum degree adjustment: If it is detected that Z1 > Z, that is, the vacuum degree is insufficient, the vacuum pumping process is started, and the following steps are executed: a. Immediately open the first solenoid valve (12) and the third solenoid valve (14); close the second solenoid valve (13) to block other non-air extraction paths. b. Start the compressor (9) to start extracting the air inside the vacuum hood (3). c. Continuously monitor the measured vacuum degree value Z1 of the air pressure sensor (5) until Z1 < Z - 50 Pa to ensure that it reaches and is slightly lower than the optimal vacuum degree range. d. After the vacuum degree reaches Z - 50 Pa, stop the operation of the compressor (9) and close the first solenoid valve (12) and the third solenoid valve (14) to exit the vacuum pumping process. e. The system components switch to the normal heating state and are ready to start the hot water heating cycle. S3. Continuous monitoring of the vacuum degree in the normal heating state: In the normal heating state, continuously monitor the inlet water temperature T1, the outlet water temperature T2 and the measured vacuum degree value Z1 of the vacuum hot water storage tank to ensure that they fluctuate within the set range; and ensure that the first solenoid valve (12) and the third solenoid valve (14) are in the closed state in the heating state. S4. Abnormal vacuum degree detection: If the measured vacuum degree value Z1 of the air pressure sensor (5) ≥ Z + 50 Pa within 10 consecutive seconds, it is determined that the vacuum degree is abnormal and needs to be evacuated again, and steps S2 and S3 are continued.

9. The control method of the vacuum anti-corrosion and anti-leakage heat pump water storage tank improvement system according to claim 8 is characterized by: In step S4, before it is determined that evacuation is required again, start the heat pump unit to run for 5 - 8 minutes.

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