PVT heat pump system, heating control method, defrosting control method and water heater

Abstract

The invention discloses a PVT heat pump system, a heating control method, a defrosting control method and a water heater. The system further comprises a second condenser, an electromagnetic valve, a second electronic expansion valve, a third electronic expansion valve, a first three-way valve and a second three-way valve. According to the PVT heat pump system, the structure of the PVT heat pump system is improved, the condenser and other components are additionally arranged, different branches are set up, based on the novel PVT heat pump system structure, high-temperature hot water of 65-70 DEG C can be produced, the requirements for hot water of 65 DEG C or above in the industries of hot spring hotels, metal processing, food, chemical engineering and the like are met, and the system still has high COP performance when the water temperature is 50 DEG C or above. In addition, the new PVT heat pump system can perform heating while defrosting, extra mains supply is almost not needed to be provided for defrosting, and the electricity utilization cost of a user is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump systems, and in particular to a PVT heat pump system, a heating control method, a defrosting control method, and a water heater. Background Art

[0002] Currently, the maximum hot water produced by conventional air-source heat pumps and existing PVT heat pumps is 60°C, which is difficult to meet the demand for hot water above 65°C in industries such as hot spring hotels, metal processing, food and chemical industries. Moreover, when the water temperature of the unit reaches 50°C or above, the system will have problems such as high condensing temperature, large compression ratio and decreased system performance.

[0003] In addition, the current conventional air-source heat pump system uses a reverse cycle defrosting method in winter to solve the problem of frosting on the heat exchanger. This will result in a failure to heat during defrosting, affecting the user experience and increasing system energy consumption.

[0004] Currently, no effective solution has been proposed for the problem that the PVT heat pump system in the prior art cannot produce high-temperature hot water and cannot generate heat during defrosting. Summary of the invention

[0005] The embodiments of the present invention provide a PVT heat pump system, a heating control method, a defrosting control method, and a water heater to solve the problem in the prior art that the PVT heat pump system cannot produce high-temperature hot water and cannot heat during defrosting.

[0006] In order to solve the above technical problems, the present invention provides a PVT heat pump system, which includes a compressor, a first condenser, a fin heat exchanger, a first electronic expansion valve, and a PVT component connected in parallel with the fin heat exchanger in sequence; the system also includes:

[0007] A second condenser is arranged on the first branch, one end of the first branch is located on the pipeline between the compressor and the first condenser, and the other end of the first branch is located on the pipeline between the first condenser and the fin heat exchanger;

[0008] A solenoid valve, arranged on a water inlet pipe of the second condenser;

[0009] a second electronic expansion valve, arranged on the first branch and between the compressor and the second condenser;

[0010] a third electronic expansion valve, arranged on the second branch, one end of the second branch being located on the pipeline between the compressor and the first condenser, and the other end being located on the pipeline between the fin heat exchanger and the first electronic expansion valve;

[0011] A first three-way valve, whose port a is connected to the first condenser, whose port b is connected to the second condenser, and whose port c is connected to tap water;

[0012] The second three-way valve is arranged on the pipeline between the first condenser and the fin heat exchanger, wherein the a port thereof is connected to the fin heat exchanger, and the b port and the c port thereof are connected to the first condenser.

[0013] Furthermore, the system further comprises:

[0014] A pressure sensor is arranged at the exhaust port of the compressor;

[0015] A temperature sensor is arranged at the water outlet of the first condenser;

[0016] The irradiance meter is arranged at the PVT component.

[0017] Furthermore, port b and port c of the second three-way valve are both one-way valves.

[0018] The present invention also provides a heating control method for a PVT heat pump system, which is applied to the above-mentioned PVT heat pump system, wherein the method includes: in the heating mode, controlling the water and refrigerant of the PVT heat pump system to exchange heat only through the first condenser; detecting the exhaust pressure of the compressor and the water outlet temperature of the first condenser, and after the exhaust pressure meets the preset pressure condition and / or the water outlet temperature meets the preset temperature condition, controlling the water and refrigerant of the PVT heat pump system to exchange heat through the first condenser and the second condenser.

[0019] Further, the preset pressure condition of the exhaust pressure includes: exhaust pressure ≥ preset pressure threshold; the preset temperature condition of the outlet water temperature includes: outlet water temperature ≥ preset temperature threshold.

[0020] Furthermore, the water and refrigerant of the PVT heat pump system are controlled to exchange heat only through the first condenser, including: controlling the solenoid valve to close, controlling the a port and the c port of the first three-way valve to be connected, controlling the a port and the c port of the second three-way valve to be connected, controlling the first electronic expansion valve to open, and controlling the second electronic expansion valve and the third electronic expansion valve to close.

[0021] Furthermore, controlling the water and refrigerant of the PVT heat pump system to exchange heat through the first condenser and the second condenser includes: controlling the solenoid valve to open, controlling the second electronic expansion valve to open, and controlling the a port and the b port of the first three-way valve to be connected.

[0022] Furthermore, after controlling the water and refrigerant of the PVT heat pump system to exchange heat through the first condenser and the second condenser, the method further includes: detecting the solar irradiance, and adjusting the opening of the second electronic expansion valve according to the irradiance.

[0023] Further, adjusting the opening of the second electronic expansion valve according to the irradiance includes: after the irradiance exceeds a preset irradiance threshold, increasing the opening of the second electronic expansion valve according to a corresponding opening adjustment ratio based on a change in the irradiance.

[0024] Furthermore, while increasing the opening of the second electronic expansion valve, the method also includes: detecting the exhaust temperature of the compressor and maintaining the exhaust temperature within a preset safety range; if the exhaust temperature exceeds the preset safety range, stopping increasing the opening of the second electronic expansion valve.

[0025] The present invention also provides a defrost control method for a PVT heat pump system, which is applied to the above PVT heat pump system, wherein the method includes: in the defrost mode, controlling part of the refrigerant of the PVT heat pump system to defrost the fin heat exchanger; at the same time, part of the refrigerant is used to make hot water through the first condenser; detecting the solar irradiance, determining whether to execute the fast defrost mode or the conventional defrost mode according to the irradiance, and controlling the opening of the third electronic expansion valve in different defrost modes.

[0026] Furthermore, part of the refrigerant of the PVT heat pump system is controlled to defrost the fin heat exchanger; at the same time, part of the refrigerant is used to heat water through the first condenser, including: controlling the solenoid valve to close, controlling the a port and the c port of the first three-way valve to be connected, controlling the a port and the b port of the second three-way valve to be connected, controlling the first electronic expansion valve and the second electronic expansion valve to close, and controlling the third electronic expansion valve to open.

[0027] Furthermore, the execution of a quick defrost mode or a conventional defrost mode is determined according to the irradiance, and the opening of the third electronic expansion valve is controlled in different defrost modes, including: if the irradiance is less than a preset value, the conventional defrost mode is executed; if the irradiance is greater than or equal to the preset value, the quick defrost mode or the conventional defrost mode is executed.

[0028] Further, executing a conventional defrosting mode includes: controlling the opening degree of the third electronic expansion valve to be k1;

[0029] Executing a fast defrost mode or a regular defrost mode includes: if the fast defrost mode is executed, controlling the opening of the third electronic expansion valve to be k2; if the regular defrost mode is executed, controlling the opening of the third electronic expansion valve to be k3; wherein k1<k3<k2.

[0030] The present invention also provides a water heater, wherein the water heater comprises the above-mentioned PVT heat pump system.

[0031] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the program implements the heating control method of the PVT heat pump system as described above, or the defrost control method of the PVT heat pump system as described above.

[0032] By applying the technical solution of the present invention, the structure of the PVT heat pump system is improved, and a second condenser, a solenoid valve, a second electronic expansion valve and a first three-way valve are added. A third electronic expansion valve and a second three-way valve and other components are also added. Different branches are built. Based on the new PVT heat pump system structure, high-temperature hot water of 65-70°C can be produced to meet the needs of hot spring hotels, metal processing, food and chemical industries for hot water above 65°C. The system still has a high COP performance when the water temperature is 50°C or above. In addition, the new PVT heat pump system can also heat while defrosting, and there is almost no need to provide additional city electricity for defrosting, reducing the user's electricity cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic structural diagram of a PVT heat pump system according to an embodiment of the present invention;

[0034] Figure 2 is a flow chart of a heating control method of a PVT heat pump system according to an embodiment of the present invention;

[0035] Figure 3 is a flow chart of a defrost control method for a PVT heat pump system according to an embodiment of the present invention;

[0036] Reference numerals:

[0037] Compressor 1, first condenser 2, fin heat exchanger 3, first electronic expansion valve 4, PVT assembly 5, second condenser 6, solenoid valve 7, second electronic expansion valve 8, third electronic expansion valve 9, first three-way valve 10, second three-way valve 11, pressure sensor 12, temperature sensor 13, irradiance meter 14. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0040] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0041] It should be understood that although the terms first, second, third, etc. may be used to describe the electronic expansion valve in the embodiments of the present invention, these should not be limited to these terms. These terms are only used to distinguish the electronic expansion valves. For example, without departing from the scope of the embodiments of the present invention, the first electronic expansion valve may also be referred to as the second electronic expansion valve, and similarly, the second electronic expansion valve may also be referred to as the first electronic expansion valve.

[0042] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0043] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0044] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0045] Example 1

[0046] Figure 1 is a schematic structural diagram of a PVT heat pump system according to an embodiment of the present invention, Figure 1 The solid line represents the refrigerant path, and the dotted line represents the water path. Figure 1As shown, the PVT heat pump system includes a compressor 1 , a first condenser, a fin heat exchanger 3 , a first electronic expansion valve 4 , and a PVT component 5 connected in parallel with the fin heat exchanger 3 , which are connected in sequence.

[0047] The PVT heat pump system is a heat pump system based on PVT (photovoltaic-thermal) technology, which can achieve heating and cooling through the use of solar energy. PVT components are photovoltaic thermal components. Figure 1 In the figure, the PVT assembly 5 including PVT1, PVT2...PVTn is taken as an example for schematic illustration, where n represents the number of PVT panels. A plurality of PVT panels are connected in parallel to form a PVT assembly, and the PVT assembly is connected in parallel with the fin heat exchanger.

[0048] The PVT heat pump system also includes:

[0049] The second condenser 6 is arranged on the first branch, one end of the first branch is located on the pipeline between the compressor 1 and the first condenser, and the other end is located on the pipeline between the first condenser and the fin heat exchanger 3;

[0050] A solenoid valve 7 is arranged on the water inlet pipe of the second condenser 6;

[0051] The second electronic expansion valve 8 is arranged on the first branch and between the compressor 1 and the second condenser 6 .

[0052] The third electronic expansion valve 9 is arranged on the second branch, one end of the second branch is located on the pipeline between the compressor 1 and the first condenser, and the other end is located on the pipeline between the fin heat exchanger 3 and the first electronic expansion valve 4;

[0053] The first three-way valve 10, whose port a is connected to the first condenser, whose port b is connected to the second condenser 6, and whose port c is connected to tap water;

[0054] The second three-way valve 11 is arranged on the pipeline between the first condenser and the fin heat exchanger 3, with its port a connected to the fin heat exchanger 3, and its ports b and c connected to the first condenser.

[0055] In the structure of the existing heat pump system, normal temperature tap water directly flows to the first condenser and performs heat exchange through the first condenser. The PVT heat pump system of this embodiment is additionally provided with a second condenser 6, a solenoid valve 7, a second electronic expansion valve 8 and a first three-way valve 10. When the solenoid valve 7 is opened, normal temperature tap water can flow into the second condenser 6 for heat exchange, and then enter the first condenser through the first three-way valve 10. The second electronic expansion valve 8 is arranged on the first branch, and can control the refrigerant flow from the compressor 1 to the second condenser 6. When the opening of the second electronic expansion valve 8 is small, the refrigerant flowing to the second condenser 6 is small, then the ac conduction of the first three-way valve 10 can be set, and part of the normal temperature tap water can flow directly to the first condenser.

[0056] In addition, the PVT heat pump system of this embodiment is further provided with a third electronic expansion valve 9 and a second three-way valve 11. Ports b and c of the second three-way valve are both one-way valves. When the PVT heat pump system is defrosted, the system refrigerant undergoes phase change and absorbs heat through the PVT component (photovoltaic thermal component), and after the compressor works, a high-temperature and high-pressure gaseous refrigerant is generated. After the third electronic expansion valve is opened, part of the high-temperature and high-pressure gaseous refrigerant enters the fin heat exchanger. At this time, the fin heat exchanger is equivalent to a condenser, and the high-temperature and high-pressure gaseous refrigerant releases heat in the fin heat exchanger, thereby achieving the effect of defrosting the fin heat exchanger; another part of the high-temperature and high-pressure gaseous refrigerant passes through the first condenser to exchange heat with water to produce hot water. In this way, it is possible to defrost and produce hot water at the same time in a low-temperature environment.

[0057] The PVT heat pump system also includes: a pressure sensor 12, which is arranged at the exhaust port of the compressor 1 and can detect the exhaust pressure of the compressor; a temperature sensor 13, which is arranged at the water outlet of the first condenser and can detect the outlet water temperature of the first condenser; and an irradiance meter 14, which is arranged at the PVT component 5 and can detect the solar irradiance. The above three parameters are key parameters for the PVT heat pump system to perform control operations during the hot water production process and the defrosting process.

[0058] This embodiment proposes a PVT heat pump system for high-temperature and high-efficiency heating and low-temperature and high-efficiency defrosting, including a fluorine system and a water system, wherein the key components that realize the functional difference between the PVT heat pump system of this embodiment and the existing system are: a second electronic expansion valve 8, a third electronic expansion valve 9, a first electronic expansion valve 4, a first three-way valve 10, a second three-way valve 11, and a second condenser 6. Based on the new PVT heat pump system structure, it can produce high-temperature hot water of 65-70°C, meeting the needs of hot spring hotels, metal processing, food and chemical industries for hot water above 65°C, and the system still has a high COP performance when the water temperature is 50°C and above. In addition, the new PVT heat pump system can also heat while defrosting, and there is almost no need to provide additional city electricity for defrosting, reducing the user's electricity cost.

[0059] This embodiment also proposes a water heater, which includes the PVT heat pump system described above. The water heater can produce high-temperature hot water at 65-70°C, meeting the needs of hot spring hotels, metal processing, food and chemical industries for hot water above 65°C.

[0060] Example 2

[0061] According to an embodiment of the present invention, a heating control method embodiment of a PVT heat pump system is provided, which is applied to the PVT heat pump system described in the above embodiment. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0062] Figure 2 is a flow chart of a heating control method of a PVT heat pump system according to an embodiment of the present invention. Figure 2 As shown, the method comprises the following steps:

[0063] Step S201, in the heating mode, controlling the water and refrigerant of the PVT heat pump system to exchange heat only through the first condenser;

[0064] Step S202, detect the exhaust pressure of the compressor and the outlet water temperature of the first condenser, and when the exhaust pressure meets the preset pressure condition and / or the outlet water temperature meets the preset temperature condition, control the water and refrigerant of the PVT heat pump system to exchange heat through the first condenser and the second condenser.

[0065] It should be noted that the exhaust pressure meets the preset pressure conditions, including: exhaust pressure ≥ preset pressure threshold (for example, 3MPa); the outlet water temperature meets the preset temperature conditions, including: outlet water temperature ≥ preset temperature threshold (for example, 50°C).

[0066] In the structure of the existing heat pump system, normal temperature tap water directly flows to the first condenser, and heat is exchanged through the first condenser. The PVT heat pump system of this embodiment is additionally provided with a second condenser, a solenoid valve, a second electronic expansion valve and a first three-way valve. When the solenoid valve is opened, normal temperature tap water can flow into the second condenser for heat exchange, and then enter the first condenser through the first three-way valve. Through double heat exchange, hot water above 65°C can be produced, meeting the demand for hot water above 65°C in industries such as hot spring hotels, metal processing, food and chemical industry. This embodiment can solve the problem that conventional air energy heat pump systems and existing PVT heat pump systems cannot produce hot water above 65°C.

[0067] The heating mode of the PVT heat pump system specifically refers to the hot water mode, and its working process is as follows:

[0068] 1. The PVT heat pump system starts up according to the preset startup logic. When it just enters the heating mode, the pressure sensor detects the exhaust pressure P0 of the compressor and the temperature sensor detects the outlet water temperature T1 of the first condenser. If the exhaust pressure does not meet the preset pressure condition (P0 ≥ P 预设 , P 预设The value can be 3MPa), and the outlet water temperature does not meet the preset temperature condition (T1≥T 预设 , T 预设 The value can be taken as 50℃), then the control solenoid valve is closed, the first three-way valve (two inlets and one outlet) is ac conductive, the second three-way valve (one inlet and two outlets) is ac conductive, the first electronic expansion valve is opened, and the second and third electronic expansion valves are fully closed.

[0069] It should be noted that when the system is just turned on and enters the heating mode, it will generally not immediately reach the exhaust pressure ≥ preset pressure threshold and the water outlet temperature ≥ preset temperature threshold. Therefore, it can also be set to directly execute the above control operations, that is, in the heating mode, control the water and refrigerant of the PVT heat pump system to exchange heat only through the first condenser, specifically including: controlling the solenoid valve to close, controlling the a port and c port of the first three-way valve to be connected, controlling the a port and c port of the second three-way valve to be connected, controlling the first electronic expansion valve to open, and controlling the second electronic expansion valve and the third electronic expansion valve to close.

[0070] Based on the above control operations, water and refrigerant exchange heat through the first condenser. The water temperature should not reach 50°C during this process. There is still a large temperature difference between the refrigerant temperature at the compressor outlet and the water temperature. Directing all high-temperature and high-pressure refrigerant to the first condenser can achieve rapid heat exchange.

[0071] 2. Detect the exhaust pressure P0 of the compressor and the outlet water temperature T1 of the first condenser. If P0≥P and / or T1≥50℃, the solenoid valve is controlled to open, the second electronic expansion valve is opened, and the first three-way valve is switched to ab conduction.

[0072] That is, after the exhaust pressure meets the preset pressure condition, and / or the outlet water temperature meets the preset temperature condition, the water and refrigerant of the PVT heat pump system are controlled to exchange heat through the first condenser and the second condenser, specifically including: controlling the solenoid valve to open, controlling the second electronic expansion valve to open, and controlling the a port and b port of the first three-way valve to be connected. Based on the above control operation, through the opening of the second electronic expansion valve, the high-temperature and high-pressure gaseous refrigerant at the outlet of the compressor is partially diverted to the second condenser for rapid heat exchange, thereby preventing the outlet pressure of the compressor from further increasing and affecting the stability of the system, and further ensuring that the water temperature can be heated to above 65°C. At the same time, the heat exchange efficiency of the refrigerant diverted to the second condenser is higher.

[0073] It should be noted that when the outlet water temperature of the second condenser reaches 50°C, the heat exchange efficiency between the refrigerant and water will be greatly reduced. At the same time, the condensation temperature of the refrigerant coming out of the second condenser is relatively high, which in turn leads to a high exhaust pressure at the compressor outlet. When the exhaust pressure of the compressor exceeds the protection value, the system will shut down. This is why the current conventional air-to-water heat pump system can only produce hot water at 60°C.

[0074] 3. After entering the high-temperature hot water process, the opening of the second electronic expansion valve is the preset opening (the size of the preset opening is related to its model and can be adjusted). In order to ensure that the PVT heat pump system still has a high COP performance when the water temperature is 50°C and above. Solve the problem that the system performance decreases when the water temperature reaches 50°C and above. This embodiment proposes a preferred implementation method, that is, to monitor the solar irradiance in real time through an irradiance meter. When the irradiance value exceeds the preset value (800w / m 2 ), as the irradiance increases, the opening of the second electronic expansion valve is increased in a certain proportion.

[0075] That is, after controlling the water and refrigerant of the PVT heat pump system to exchange heat through the first condenser and the second condenser, the solar irradiance is detected, and the opening of the second electronic expansion valve is adjusted according to the irradiance. Specifically, after the irradiance exceeds the preset irradiance threshold, the opening of the second electronic expansion valve is increased according to the corresponding opening adjustment ratio according to the change value of the irradiance. This can effectively ensure that the PVT heat pump system still has a high COP performance when the water temperature is 50°C or above.

[0076] While increasing the opening of the second electronic expansion valve, the safety of the compressor needs to be ensured. Therefore, the exhaust temperature of the compressor needs to be detected at the same time to maintain the exhaust temperature within a preset safety range. If the exhaust temperature exceeds the preset safety range, stop increasing the opening of the second electronic expansion valve.

[0077] It should be noted that when the exhaust temperature of the compressor is high, the exhaust pressure of the compressor will be very high. If the second electronic expansion valve is not opened, it will cause the pressure alarm of the compressor, so the second electronic expansion valve needs to be opened. When the light intensity is high, the PVT component brings a lot of heat, resulting in a higher suction temperature of the compressor, which will lead to higher exhaust pressure. Therefore, it is necessary to further increase the opening of the second electronic expansion valve, which can reduce the temperature of the first condenser and reduce the exhaust pressure of the compressor. When the opening of the second electronic expansion valve is small and the water volume of the second condenser is small, a, b, and c of the first three-way valve are connected; when the opening of the second electronic expansion valve is large and the water volume of the second condenser is large, a and b of the first three-way valve are connected.

[0078] Example 3

[0079] Figure 3 is a flow chart of a defrost control method for a PVT heat pump system according to an embodiment of the present invention. The defrost control method is applied to the PVT heat pump system described in the above embodiment. Figure 3 As shown, the method comprises the following steps:

[0080] Step S301, in the defrost mode, controlling part of the refrigerant of the PVT heat pump system to defrost the fin heat exchanger; at the same time, part of the refrigerant is used to heat water through the first condenser;

[0081] Step S302, detecting the solar irradiance, determining whether to execute the fast defrost mode or the normal defrost mode according to the irradiance, and controlling the opening of the third electronic expansion valve in different defrost modes.

[0082] This embodiment can solve the problem that the existing air-energy water heater cannot generate heat during defrosting, which affects the user experience and increases the energy consumption of the system.

[0083] The working process of the defrost control method of the PVT heat pump system is as follows:

[0084] 1. The PVT heat pump system is turned on according to the preset defrost mode. At this time, the solenoid valve is closed, the first three-way valve is ac-conducted, the second three-way valve is ab-conducted, the first electronic expansion valve and the second electronic expansion valve are closed, and the third electronic expansion valve is opened.

[0085] That is, the present embodiment performs heating while defrosting, which is achieved through the following control operations: controlling the solenoid valve to close, controlling the a and c ports of the first three-way valve to be connected, controlling the a and b ports of the second three-way valve to be connected, controlling the first electronic expansion valve and the second electronic expansion valve to close, and controlling the third electronic expansion valve to open.

[0086] Based on the above control operation, the system refrigerant passes through the PVT component (photovoltaic thermal component) to absorb heat through phase change, and then passes through the compressor to produce high-temperature and high-pressure gaseous refrigerant. Since the third electronic expansion valve is open, part of the high-temperature and high-pressure gaseous refrigerant enters the fin heat exchanger. At this time, the fin heat exchanger is equivalent to a condenser. The high-temperature and high-pressure gaseous refrigerant releases heat in the fin heat exchanger, thereby achieving the effect of defrosting the fin heat exchanger; another part of the high-temperature and high-pressure gaseous refrigerant passes through the first condenser to exchange heat with water to produce hot water. In this way, it is possible to defrost and produce hot water at the same time in a low-temperature environment.

[0087] 2. Adjust the opening of the third electronic expansion valve according to the defrost mode (fast defrost mode, normal defrost mode).

[0088] That is, determining whether to execute the fast defrost mode or the conventional defrost mode according to the irradiance, and controlling the opening degree of the third electronic expansion valve in different defrost modes, including:

[0089] If the irradiance is less than the preset value, it means that the current light is not strong enough and the PVT component cannot obtain much heat, so only the conventional defrost mode can be executed;

[0090] Executing a conventional defrosting mode includes: controlling the opening degree of the third electronic expansion valve to be k1;

[0091] If the irradiance is ≥ the preset value, it means that the light intensity is strong and the PVT component can obtain more heat. You can choose to execute the fast defrost mode or the regular defrost mode.

[0092] Executing the fast defrost mode or the regular defrost mode includes: if the fast defrost mode is executed, controlling the opening of the third electronic expansion valve to be k2; if the regular defrost mode is executed, controlling the opening of the third electronic expansion valve to be k3; wherein k1<k3<k2.

[0093] It should be noted that the larger the opening of the third electronic expansion valve, the more high-temperature and high-pressure gaseous refrigerant flows to the fin heat exchanger, and the better and faster the defrosting effect. Therefore, when executing the fast defrost mode, the opening of the third electronic expansion valve is controlled to be k2, and the value of k2 is set to be higher. When the conventional defrost mode is executed when the light intensity is not strong, the opening of the third electronic expansion valve cannot be set too large, because it is necessary to ensure the effect of hot water production while defrosting, and it is necessary to ensure that when the light intensity is not strong, more high-temperature and high-pressure gaseous refrigerant passes through the first condenser to exchange heat with water to produce hot water. Therefore, the value of k1 is set to be lower.

[0094] The following is a detailed introduction:

[0095] After entering the defrost mode, first read the irradiance E0 and compare it with the preset value E (300w / m 2 ) comparison, if E0<E, the PVT heat pump system is not allowed to enter the fast defrost mode. The details are as follows:

[0096] 21) When E0≥E, two modes can be selected: conventional defrost and fast defrost. The stronger the light intensity, the more heat the PVT components obtain, and the fast defrost mode can be executed.

[0097] In normal defrost mode:

[0098] Overall, it is ensured that the refrigerant flow through the third electronic expansion valve (i.e. the flow to the fin heat exchanger) accounts for about 1 / 3 of the total flow through the compressor outlet. Taking a 2.0C electronic expansion valve as an example, the opening is about 200 steps.

[0099] In fast defrost mode:

[0100] Overall, it is ensured that the refrigerant flow rate flowing through the third electronic expansion valve accounts for about 1 / 2 of the total flow rate flowing through the compressor outlet. Taking a 2.0C electronic expansion valve as an example, the opening degree is about 350 steps.

[0101] 22) E0<<E, only conventional defrost mode can be performed, and the overall refrigerant flow through the third electronic expansion valve must account for about 1 / 4 of the total flow through the compressor outlet. Taking a 2.0C electronic expansion valve as an example, the opening is about 150 steps.

[0102] Example 4

[0103] This embodiment provides an electronic device, which is used in a heating control method of a PVT heat pump system. The electronic device includes: at least one processor; and a memory connected to the at least one processor in communication; wherein:

[0104] The memory stores instructions executable by the one processor, the instructions being executed by the at least one processor to enable the at least one processor to:

[0105] In the heating mode, the water and refrigerant of the PVT heat pump system are controlled to exchange heat only through the first condenser; the exhaust pressure of the compressor and the water outlet temperature of the first condenser are detected, and when the exhaust pressure meets the preset pressure condition and / or the water outlet temperature meets the preset temperature condition, the water and refrigerant of the PVT heat pump system are controlled to exchange heat through the first condenser and the second condenser.

[0106] Example 5

[0107] This embodiment provides an electronic device, which is used in a defrost control method for a PVT heat pump system. The electronic device includes: at least one processor; and a memory connected to the at least one processor in communication; wherein:

[0108] The memory stores instructions executable by the one processor, the instructions being executed by the at least one processor to enable the at least one processor to:

[0109] In the defrost mode, part of the refrigerant of the PVT heat pump system is controlled to defrost the fin heat exchanger; at the same time, part of the refrigerant is used to heat water through the first condenser; the solar irradiance is detected, and the execution of the fast defrost mode or the conventional defrost mode is determined according to the irradiance, and the opening of the third electronic expansion valve is controlled in different defrost modes.

[0110] Example 6

[0111] The embodiment of the present invention provides a software, which is used to execute the technical solutions described in the above embodiment and preferred implementation manner.

[0112] An embodiment of the present invention provides a non-volatile computer storage medium, which stores computer executable instructions. The computer executable instructions can execute the heating control method and the defrost control method of the PVT heat pump system in any of the above method embodiments.

[0113] The above-mentioned software is stored in the above-mentioned storage medium, which includes but is not limited to: a CD, a floppy disk, a hard disk, an erasable memory, etc.

[0114] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0115] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0116] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0117] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0118] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0119] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0120] The above product can execute the method provided by the embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not described in detail in this embodiment, please refer to the method provided by the embodiment of the present invention.

[0121] The electronic devices of the embodiments of the present invention exist in various forms, including but not limited to:

[0122] (1) Mobile communication devices: These devices are characterized by their mobile communication functions and their main purpose is to provide voice and data communications. These terminals include: smart phones (such as iPhone), multimedia phones, functional phones, and low-end phones.

[0123] (2) Ultra-mobile personal computer devices: These devices fall into the category of personal computers, have computing and processing capabilities, and generally also have mobile Internet access features. These terminals include: PDA, MID and UMPC devices, such as iPad.

[0124] (3) Portable entertainment devices: These devices can display and play multimedia content. They include audio and video players (such as iPods), handheld game consoles, e-books, as well as smart toys and portable car navigation devices.

[0125] (4) Server: A device that provides computing services. The server consists of a processor, hard disk, memory, device bus, etc. The server is similar to the general computer architecture, but because it needs to provide highly reliable services, it has higher requirements in terms of processing power, stability, reliability, security, scalability, manageability, etc.

[0126] (5) Other electronic devices with data interaction functions, such as televisions, large-screen cars, etc.

[0127] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A PVT heat pump system, characterized in that: The system includes a compressor, a first condenser, a fin heat exchanger, a first electronic expansion valve, and a PVT component connected in parallel with the fin heat exchanger in sequence; the system also includes: A second condenser is arranged on the first branch, one end of the first branch is located on the pipeline between the compressor and the first condenser, and the other end of the first branch is located on the pipeline between the first condenser and the fin heat exchanger; A solenoid valve, arranged on a water inlet pipe of the second condenser; A second electronic expansion valve is arranged on the first branch and between the compressor and the second condenser; a third electronic expansion valve, arranged on the second branch, one end of the second branch being located on the pipeline between the compressor and the first condenser, and the other end being located on the pipeline between the fin heat exchanger and the first electronic expansion valve; A first three-way valve, whose port a is connected to the first condenser, whose port b is connected to the second condenser, and whose port c is connected to tap water; The second three-way valve is arranged on the pipeline between the first condenser and the fin heat exchanger, wherein the a port thereof is connected to the fin heat exchanger, and the b port and the c port thereof are connected to the first condenser.

2. The system according to claim 1, characterized in that The system further comprises: A pressure sensor is arranged at the exhaust port of the compressor; A temperature sensor is arranged at the water outlet of the first condenser; The irradiance meter is arranged at the PVT component.

3. The system according to claim 1, characterized in that Port b and port c of the second three-way valve are both one-way valves.

4. A heating control method for a PVT heat pump system, applied to the PVT heat pump system according to any one of claims 1 to 3, characterized in that: The method comprises: In the heating mode, the water and the refrigerant of the PVT heat pump system are controlled to exchange heat only through the first condenser; Detect the exhaust pressure of the compressor and the outlet water temperature of the first condenser. When the exhaust pressure meets the preset pressure condition and / or the outlet water temperature meets the preset temperature condition, control the water and refrigerant of the PVT heat pump system to exchange heat through the first condenser and the second condenser.

5. The method according to claim 4, characterized in that The preset pressure condition of the exhaust pressure includes: exhaust pressure ≥ preset pressure threshold; The preset temperature condition of the outlet water temperature includes: the outlet water temperature ≥ the preset temperature threshold.

6. The method according to claim 4, characterized in that Controlling the water and the refrigerant of the PVT heat pump system to exchange heat only through the first condenser, comprising: Control the solenoid valve to close, control the a port and c port of the first three-way valve to be connected, control the a port and c port of the second three-way valve to be connected, control the first electronic expansion valve to open, and control the second electronic expansion valve and the third electronic expansion valve to close.

7. The method according to claim 4, characterized in that Control the water and refrigerant of the PVT heat pump system to exchange heat through the first condenser and the second condenser, including: The solenoid valve is controlled to open, the second electronic expansion valve is controlled to open, and the port a and port b of the first three-way valve are controlled to be connected.

8. The method according to claim 4, characterized in that After controlling the water and the refrigerant of the PVT heat pump system to exchange heat through the first condenser and the second condenser, the method further includes: The solar irradiance is detected, and the opening of the second electronic expansion valve is adjusted according to the irradiance.

9. The method according to claim 8, characterized in that Adjusting the opening of the second electronic expansion valve according to the irradiance includes: After the irradiance exceeds a preset irradiance threshold, the opening of the second electronic expansion valve is increased according to the change value of the irradiance and the corresponding opening adjustment ratio.

10. The method according to claim 9, characterized in that While increasing the opening of the second electronic expansion valve, the method further includes: Detecting the exhaust temperature of the compressor and maintaining the exhaust temperature within a preset safe range; If the exhaust gas temperature exceeds the preset safety range, the step of increasing the opening of the second electronic expansion valve is stopped.

11. A defrost control method for a PVT heat pump system, applied to the PVT heat pump system according to any one of claims 1 to 3, characterized in that: The method comprises: In the defrost mode, part of the refrigerant of the PVT heat pump system is controlled to defrost the fin heat exchanger; at the same time, part of the refrigerant is used to heat water through the first condenser; The solar irradiance is detected, and the execution of the quick defrost mode or the conventional defrost mode is determined according to the irradiance, and the opening degree of the third electronic expansion valve is controlled in different defrost modes.

12. The method according to claim 11, characterized in that Controlling part of the refrigerant of the PVT heat pump system to defrost the fin heat exchanger; at the same time, part of the refrigerant is used to heat water through the first condenser, including: Control the solenoid valve to close, control the a and c ports of the first three-way valve to be connected, control the a and b ports of the second three-way valve to be connected, control the first and second electronic expansion valves to close, and control the third electronic expansion valve to open.

13. The method according to claim 11, characterized in that Determining whether to execute a fast defrost mode or a conventional defrost mode according to the irradiance, and controlling the opening of the third electronic expansion valve in different defrost modes, including: If the irradiance is less than the preset value, a conventional defrosting mode is executed; If the irradiance is greater than or equal to the preset value, the fast defrost mode or the normal defrost mode is executed.

14. The method according to claim 13, characterized in that Executing a conventional defrosting mode includes: controlling the opening degree of the third electronic expansion valve to be k1; Executing a fast defrost mode or a regular defrost mode, comprising: if the fast defrost mode is executed, controlling the opening degree of the third electronic expansion valve to be k2; if the regular defrost mode is executed, controlling the opening degree of the third electronic expansion valve to be k3; Among them, k1<k3<k2.

15. A water heater, characterized in that: The water heater comprises the PVT heat pump system according to any one of claims 1 to 3.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the heating control method of the PVT heat pump system according to any one of claims 4 to 10 or the defrosting control method of the PVT heat pump system according to any one of claims 11 to 14 is implemented.

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