Photovoltaic photo-thermal heat pump system, control method thereof and air conditioning system

Abstract

The invention discloses a photovoltaic photo-thermal heat pump system, a control method of the photovoltaic photo-thermal heat pump system and an air conditioning system. The photovoltaic photo-thermal heat pump system comprises a main refrigerant flow path provided with a compressor, a first branch connected with the main refrigerant flow path and provided with a photovoltaic photo-thermal assembly, and a second branch connected with the main refrigerant flow path and provided with a first heat exchanger. A first adjusting valve is arranged at the joint of the main refrigerant flow path and the first branch and the joint of the main refrigerant flow path and the second branch, and the first adjusting valve can distribute the proportion of refrigerants flowing into the first branch and the second branch in the main refrigerant flow path. Compared with the prior art, according to the system for connecting the heat pump system and the photovoltaic photo-thermal assembly in parallel and the control method, the refrigerant pump is matched with the adjusting valve, so that the power consumption of the compressor under various working conditions is reduced; and meanwhile, the working point of the photovoltaic photo-thermal heat pump system is adjusted by comparing the power consumption increment of the compressor with the total gain of the photovoltaic photo-thermal heat pump system, so that the optimal energy efficiency working point is achieved.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic power generation, and in particular to a photovoltaic thermal heat pump system and a control method thereof, and an air conditioning system. Background Art

[0002] Photovoltaic thermal heat pump systems can utilize both photovoltaic (electrical energy) and thermal (thermal) solar energy. Due to the temperature characteristics of crystalline silicon photovoltaic thermal modules, the power generation efficiency of crystalline silicon modules under high temperature conditions is often lower than the test results under its standard state. In addition, high temperature will also affect the life of photovoltaic cells. Photovoltaic thermal modules are currently able to carry away and utilize the waste heat of photovoltaic thermal modules while generating photovoltaic power. The basic principle of the photovoltaic thermal heat pump system is to use the heat generated in the photovoltaic power generation process to improve the energy efficiency of the heat pump system or achieve energy saving and carbon reduction.

[0003] The current photovoltaic thermal modules are roughly divided into two categories according to the structure or the type of circulating medium: one is that the refrigerant flows directly through the photovoltaic thermal module and takes away the heat, which includes common structures such as direct expansion type and tube-sheet type; the other is that the coolant flows through the photovoltaic thermal module and takes away the heat to a heat exchanger, and the other side of the heat exchanger is connected to the refrigerant circulation system. Obviously, the former belongs to direct heat exchange, which is more efficient and more compact. But there are also problems as follows.

[0004] Photovoltaic thermal modules generally have a large plane area and a small thickness, which reduces weight and volume and facilitates transportation and installation. Photovoltaic thermal modules are equivalent to adding a cold plate to the back of conventional photovoltaic thermal modules. Although the thickness has increased to a certain extent, it will not increase significantly in the optimal design (because the convenience of using conventional photovoltaic thermal modules must be taken into account). This results in greater resistance when the refrigerant or other working fluid flows through the photovoltaic thermal module (compared to the radiator of a conventional heat pump system), resulting in greater parasitic power consumption, which ultimately limits the improvement of system energy efficiency, and even reduces energy efficiency under extreme conditions.

[0005] Therefore, how to design a photovoltaic thermal heat pump system and its control method and air-conditioning system that can solve the problem of low energy efficiency of the photovoltaic thermal heat pump system under certain working conditions is a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention proposes a photovoltaic thermal heat pump system and a control method thereof, and an air conditioning system.

[0007] The technical solution of the present invention is to propose a photovoltaic thermal heat pump system, comprising a main refrigerant flow path provided with a compressor, a first branch connected to the main refrigerant flow path and provided with a photovoltaic thermal component, and a second branch connected to the main refrigerant flow path and provided with a first heat exchanger;

[0008] A first regulating valve is provided at the connection between the main refrigerant flow path and the first branch and the second branch, and the first regulating valve can distribute the ratio of the refrigerant in the main refrigerant flow path flowing into the first branch and the second branch.

[0009] Furthermore, it also includes a refrigerant pump arranged in the first branch and a second regulating valve arranged in the second branch, the refrigerant pump can adjust the flow rate of the refrigerant in the first branch, and the second regulating valve is used to adjust the resistance characteristics of the second branch.

[0010] Furthermore, it also includes a first sensor and a second sensor arranged in the first branch;

[0011] The first sensor is located at the input side of the photovoltaic thermal assembly, and the second sensor is located at the output side of the photovoltaic thermal assembly;

[0012] The first sensor and the second sensor are used to detect the physical state of the photovoltaic thermal component.

[0013] Furthermore, it also includes a third regulating valve arranged on the main refrigerant flow path, the third regulating valve is connected to a refrigerant bypass, and the other side of the refrigerant bypass is connected to the first branch.

[0014] Further, when the photovoltaic thermal heat pump system operates in a heating mode, the photovoltaic thermal component is used as an evaporator, and the first heat exchanger is configured as a condenser;

[0015] When the photovoltaic thermal heat pump system operates in a cooling mode, the photovoltaic thermal component is used as a condenser, and the first heat exchanger is configured as an evaporator.

[0016] Furthermore, the main refrigerant flow path is also provided with a first throttle valve, a second throttle valve, and a second heat exchanger;

[0017] The second heat exchanger serves as an input side of the main refrigerant flow path, and is used to receive the refrigerant returning from the first branch and the second branch;

[0018] The first throttle valve is disposed between the compressor and the first regulating valve, and the second throttle valve is disposed between the compressor and the second heat exchanger.

[0019] Furthermore, the average temperature of the photovoltaic thermal assembly satisfies the calculation model:

[0020] Tcell=f(Q,a,m1,m2,T1,T2,c,Tf,h)

[0021] Among them, Q is the irradiance, a is the photoelectric conversion efficiency, T1 is the refrigerant temperature detected by the first sensor, T2 is the refrigerant temperature detected by the second sensor, m1 is the refrigerant flow detected by the first sensor, m2 is the refrigerant flow detected by the second sensor, c is the specific heat capacity of the refrigerant, Tf is the ambient temperature, h is the comprehensive heat transfer coefficient, and Tcell is the average temperature of the photovoltaic thermal component.

[0022] The present invention also proposes a control method using the above-mentioned photothermal heat pump system, which comprises:

[0023] Detecting the operating condition of the photovoltaic thermal heat pump system;

[0024] When the photovoltaic thermal heat pump system works in a heating mode, the photovoltaic thermal component is used as an evaporator, and waste heat from the photovoltaic thermal component is used to heat the refrigerant;

[0025] When the photovoltaic thermal heat pump system operates in a cooling mode, the photovoltaic thermal component is used as a condenser, and the radiation heat dissipation capacity of the photovoltaic thermal component is used to cool the refrigerant.

[0026] Furthermore, it also includes:

[0027] When the photovoltaic thermal assembly is in a power generation state, detecting the increase in compressor power consumption and the total gain of the photovoltaic thermal heat pump system;

[0028] Determining whether the increase in compressor power consumption is less than the total gain of the photovoltaic thermal heat pump system;

[0029] When the judgment is yes, the refrigerant flow rate of the first branch is increased so that the increase in the power consumption of the compressor is equal to the total gain of the photovoltaic thermal heat pump system.

[0030] The present invention also proposes an air conditioning system, which has the above-mentioned photovoltaic thermal heat pump system.

[0031] Compared with the prior art, the present invention has at least the following beneficial effects:

[0032] 1. The present invention is provided with a first regulating valve, a second regulating valve, and a refrigerant pump, which can reasonably distribute the refrigerant flow rate. When a large amount of heat absorption is required, more refrigerant can pass through the photovoltaic thermal component, and when a large amount of heat dissipation is required, more refrigerant can flow through the radiator, thereby reducing the energy consumption of the compressor under some working conditions;

[0033] 2. The present invention also detects the increase in compressor power consumption and the total gain of the photovoltaic thermal heat pump system, and when the photovoltaic thermal component is in the power generation state, adjusts the working point of the photovoltaic thermal heat pump system to make the increase in compressor power consumption and the total gain of the photovoltaic thermal heat pump system equal. Through this control, the photovoltaic thermal heat pump system can operate at the optimal energy efficiency working point to ensure the optimization of system energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Figure 1 This is a basic principle diagram of the photovoltaic thermal heat pump system proposed in the present invention;

[0036] Figure 2 This is an overall control flow chart of the photovoltaic thermal heat pump system of the present invention;

[0037] Figure 3 This is a basic principle diagram of a photovoltaic thermal heat pump system in another embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0040] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0041] Photovoltaic thermal modules generally have a large plane area and a small thickness, which reduces weight and volume and facilitates transportation and installation. Photovoltaic thermal modules are equivalent to adding a cold plate to the back of conventional photovoltaic thermal modules. Although the thickness has increased to a certain extent, it will not increase significantly in the optimal design (because the convenience of using conventional photovoltaic thermal modules must be taken into account). This results in greater resistance when the refrigerant or other working fluid flows through the photovoltaic thermal module (compared to the radiator of a conventional heat pump system), resulting in greater parasitic power consumption, which ultimately limits the improvement of system energy efficiency, and even reduces energy efficiency under extreme conditions.

[0042] In response to the above problems, the design idea of ​​the present invention is to connect the photovoltaic thermal component and the heat exchanger in parallel, and distribute the refrigerant flowing through the photovoltaic thermal component and the refrigerant flowing through the heat exchanger through a regulating valve, to ensure that when a large amount of heat absorption is needed, more refrigerant passes through the photovoltaic thermal component, and when a large amount of heat dissipation is needed, more refrigerant flows through the radiator, so as to reduce the power consumption of the compressor under some working conditions.

[0043] Based on the above ideas, the photovoltaic thermal heat pump system proposed in the present invention includes: a main refrigerant flow path provided with a compressor, a first branch connected to the main refrigerant flow path and provided with a photovoltaic thermal component, and a second branch connected to the main refrigerant flow path and provided with a first heat exchanger;

[0044] Wherein, a first regulating valve is provided at the connection between the main refrigerant flow path and the first branch and the second branch, and the first regulating valve can distribute the ratio of the refrigerant in the main refrigerant flow path flowing into the first branch and the second branch.

[0045] See also Figure 1 , the main refrigerant flow path is a flow path provided with throttle 1 (i.e., the first throttle valve), a compressor, a sensor 3 (i.e., the third sensor), throttle 2 (i.e., the second throttle valve), and a heat exchanger 2 (i.e., the second heat exchanger);

[0046] The first branch is a flow path provided with a refrigerant pump, a sensor 1 (also the first sensor), a photovoltaic thermal component, and a sensor 2 (also the second sensor);

[0047] The second branch is a flow path provided with a heat exchanger 1 (also known as the first heat exchanger) and a valve 2 (also known as the second regulating valve);

[0048] The first regulating valve is also valve 1;

[0049] It can be seen that the first branch and the second branch are in a parallel relationship and are connected through the first regulating valve;

[0050] Based on the above connection relationship, the first regulating valve can realize the diversion of the total refrigerant flow, one way enters the first branch, and the other way enters the second branch, and the flow ratio of the two can be adjusted from 1:0 to 0:1 by adjusting the opening of the first regulating valve;

[0051] The purpose of setting the above distribution method in the present invention is to adjust the heat exchange characteristics of the first branch and the second branch. Although the above structure connects the photovoltaic thermal component and the first heat exchanger in parallel, the refrigerant flow rate flowing through them is not fixed (that is, the flow distribution ratio is not fixed). When a large amount of heat absorption is required, more refrigerant can flow through the first branch, that is, heat absorption is performed through the photovoltaic thermal component. When a large amount of heat dissipation is required, more refrigerant can flow through the first heat exchanger;

[0052] Based on the above allocation, the power consumption of the compressor under some working conditions can be reduced to a certain extent.

[0053] See also Figure 1 The present invention also includes a refrigerant pump arranged in the first branch and a second regulating valve arranged in the second branch. The refrigerant pump can adjust the flow rate of the refrigerant in the first branch, and the second regulating valve is used to adjust the resistance characteristics of the second branch.

[0054] It should be noted here that during the normal operation of the photovoltaic thermal heat pump system, the MAP diagram of the compressor is reflected as an area rather than a line. Although the flow rate of the refrigerant can be adjusted by adjusting the opening of the first regulating valve, the adjustment range takes priority and there is no way to meet all working conditions, especially there is no way to achieve energy efficiency optimization under some working conditions. For this reason, the present invention is provided with a refrigerant pump, which only needs to consume less energy to achieve the flow and distribution of the refrigerant, and sometimes the compressor does not even need to be started.

[0055] The present invention adopts a low-power refrigerant pump to achieve precise regulation of refrigerant flow and distribution under low-flow conditions, thereby achieving energy consumption optimization while meeting system requirements.

[0056] See also Figure 1 , the present invention further comprises a first sensor and a second sensor arranged in the first branch;

[0057] The first sensor is located at the input side of the photovoltaic thermal assembly, and the second sensor is located at the output side of the photovoltaic thermal assembly;

[0058] The first sensor and the second sensor are used to detect the physical state of the photovoltaic thermal assembly.

[0059] from Figure 1It can be seen that for the main refrigerant flow path and the first branch, the flow direction of the refrigerant is: compressor, first throttle valve, first regulating valve, refrigerant pump, first sensor, photovoltaic thermal component, second regulating valve, second heat exchanger, second throttle valve, third sensor, compressor;

[0060] It can be seen that, for the photovoltaic thermal assembly, the side where the refrigerant flows in is the side where the first sensor is arranged, that is, the input side mentioned above, and the side where the refrigerant flows out is the side where the second sensor is arranged, that is, the output side mentioned above;

[0061] The first sensor and the second sensor may be integrated temperature and pressure sensors, or may be sensors formed by connecting a plurality of single sensors in parallel, and may be specifically designed according to cost control requirements;

[0062] After the first sensor and the second sensor are set, the physical state of the refrigerant entering and exiting the photovoltaic thermal assembly can be accurately detected in real time, and the physical state includes: temperature, pressure, flow, etc.;

[0063] After identifying the above-mentioned physical states such as temperature, pressure, flow, etc., the phase state of the refrigerant (gas, liquid, or two-phase flow state) can be determined, so that unfavorable working conditions can be identified to avoid damage to the compressor or refrigerant pump caused by inappropriate phase state;

[0064] In addition, since photovoltaic thermal components generally have a large heat exchange area, the blowing plates or other structures commonly used in the refrigerant flow space of the device are very likely to leak. After the present invention detects the flow difference or pressure difference between the input side and the output side of the photovoltaic thermal component through the above-mentioned first sensor and second sensor, it can reflect the airtightness of the refrigerant flow path of the photovoltaic thermal component based on whether the flow difference or pressure difference is abnormal (a certain pressure drop is set when the photovoltaic thermal component leaves the factory. If the pressure drop is exceeded, it indicates that there may be a leakage problem), thereby improving the reliability of the system.

[0065] See also Figure 3 The present invention further comprises a third regulating valve disposed on the main refrigerant flow path, the third regulating valve being connected to a refrigerant bypass, the other side of which is connected to the first branch;

[0066] The above design is a connection method under another embodiment of the present invention. Figure 1 In terms of connection mode, a refrigerant bypass and a third regulating valve connected to the refrigerant bypass are added in this embodiment, so that not all refrigerant needs to flow through the compressor, which further broadens the working range of the present invention under several extreme working conditions.

[0067] For example, in case 1: in the heating cycle, the photovoltaic thermal module acts as an evaporator (e.g., the sunlight irradiance is good during the day), and its performance is higher than the conventional evaporator of the air source heat pump, and when the heat demand of the above photovoltaic thermal heat pump system is less than the solar heat absorbed by the photovoltaic thermal module;

[0068] In case 2: In the refrigeration cycle, the photovoltaic thermal module acts as a condenser (for example, the radiation heat dissipation is stronger at night), and its performance is higher than the conventional condenser of the air source heat pump, and when the cooling demand of the photovoltaic thermal heat pump system is less than the radiation heat dissipation of the photovoltaic thermal module;

[0069] For the above situations 1 and 2, after the refrigerant passes through the second throttle valve, it can directly distribute the flow through the third regulating valve, so that a larger proportion or all of the refrigerant directly enters the refrigerant pump without passing through the compressor, which can further improve the energy efficiency of the photovoltaic thermal heat pump system.

[0070] That is, in the above introduction, the working range of the present invention under certain extreme working conditions is further broadened.

[0071] Based on the above principle, it can be seen that the above photovoltaic thermal assembly can be used as an evaporator or a condenser. For example, in case 1, the photovoltaic thermal assembly is used as an evaporator, which can provide heat through the solar energy absorbed by the photovoltaic thermal assembly;

[0072] As another example, in situation 2, the photovoltaic thermal component is used as a condenser, which can radiate heat outward through the photovoltaic thermal component.

[0073] See also Figure 1 The first heat exchanger and the second heat exchanger can both be evaporators or condensers. Together with the throttle valve and the compressor, the loop formed by the second branch connected to the main refrigerant flow path actually constitutes the four major components of the air-conditioning system. Therefore, when the photovoltaic thermal heat pump system works in the heating mode, when the photovoltaic thermal component is used as an evaporator, in order to cooperate with the refrigerant distribution of the first regulating valve, the first heat exchanger can be set as a condenser;

[0074] Similarly, when the photovoltaic thermal heat pump system operates in cooling mode, the photovoltaic thermal component is used as a condenser, and the first heat exchanger can be set as an evaporator to cooperate with the refrigerant distribution of the first regulating valve.

[0075] Specifically, the second branch and the main refrigerant flow path constitute four major components of the air conditioning system, and can also independently perform cooling or heating cycles. The main refrigerant flow path is also provided with a first throttle valve, a second throttle valve, and a second heat exchanger;

[0076] The specific connection method is:

[0077] The second heat exchanger serves as the input side of the main refrigerant flow path, and is used to receive the refrigerant returning from the first branch and the second branch;

[0078] The first throttle valve is arranged between the compressor and the first regulating valve, and the second throttle valve is arranged between the compressor and the second heat exchanger.

[0079] Among them, for the above-mentioned second branch, which constitutes the four major components of the air conditioning system, its compressor is used to compress the gaseous refrigerant into a high-temperature and high-pressure liquid refrigerant at high temperature and high pressure;

[0080] The condenser is used to convert high temperature and high pressure liquid refrigerant into room temperature and high pressure liquid refrigerant under room temperature and high pressure;

[0081] The evaporator is used to convert the liquid refrigerant at room temperature and high pressure into the gaseous refrigerant at low temperature and low pressure;

[0082] The low-temperature and low-pressure gaseous refrigerant will return to the compressor to form a refrigeration cycle.

[0083] Furthermore, the average temperature of the photovoltaic thermal assembly in the present invention satisfies the calculation model:

[0084] Tcell=f(Q,a,m1,m2,T1,T2,c,Tf,h)

[0085] Among them, Q is the irradiance, a is the photoelectric conversion efficiency, T1 is the refrigerant temperature detected by the first sensor, T2 is the refrigerant temperature detected by the second sensor, m1 is the refrigerant flow detected by the first sensor, m2 is the refrigerant flow detected by the second sensor, c is the specific heat capacity of the refrigerant, Tf is the ambient temperature, h is the comprehensive heat transfer coefficient, and Tcell is the average temperature of the photovoltaic thermal component.

[0086] Based on the above principle, the average temperature of the photovoltaic thermal module is a function of irradiance, environmental conditions, and refrigerant heat dissipation. At the same time, the power generation of the photovoltaic thermal module is affected by the temperature of the photovoltaic thermal module, showing a negative correlation.

[0087] Obviously, under higher irradiance (such as noon), the temperature of photovoltaic thermal components will rise. In order to ensure that the temperature of photovoltaic thermal components is not too high and affect the power generation efficiency and life, it can generally only be cooled by increasing the heat dissipation of the refrigerant circulation: that is, increasing the refrigerant flow rate (when the refrigerant temperature remains unchanged), so the power consumption of the refrigerant pump increases and the power consumption of the compressor increases.

[0088] Fine-tune the operating point of the photovoltaic-thermal heat pump system at a certain operating point (for example, increase the operating temperature of the photovoltaic-thermal component by 1°C), and detect the increase in power consumption dQ of the refrigerant pump and compressor and the total gain dB of the photovoltaic-thermal heat pump system (mainly power generation gain and life extension gain). When dQ < dB, continue to adjust the operating point of the system in the positive direction of the fine-tuning of the operating point according to a certain step size until dQ and dB are equivalent.

[0089] A certain threshold can also be set to maintain the existing operating state unchanged when the component temperature is not higher than a certain temperature.

[0090] Here, continuing to adjust the operating point of the system in the positive direction of the fine-tuning of the operating point is because when the increase in compressor power consumption is less than the total gain of the photovoltaic-thermal heat pump system, that is, when dQ < dB, it means that increasing a little compressor power consumption can换来 more benefits than this part of the power consumption. Therefore, the system can continue to be adjusted in the direction of increasing compressor power consumption to obtain greater benefits.

[0091] On the contrary, when the increase in compressor power consumption is greater than the total gain of the photovoltaic-thermal heat pump system, that is, when dQ > dB, it is not appropriate to continue the adjustment.

[0092] Based on the above principle, the present invention proposes a control method for a photovoltaic-thermal heat pump system, which includes:

[0093] Detect the operating conditions of the photovoltaic-thermal heat pump system;

[0094] When the photovoltaic-thermal heat pump system operates in the heating mode, use the photovoltaic-thermal component as an evaporator and use the waste heat of the photovoltaic-thermal component to heat the refrigerant;

[0095] When the photovoltaic-thermal heat pump system operates in the cooling mode, use the photovoltaic-thermal component as a condenser and use the radiation heat dissipation ability of the photovoltaic-thermal component to cool the refrigerant.

[0096] And further includes:

[0097] When the photovoltaic-thermal component is in the power generation state, detect the increase in compressor power consumption and the total gain of the photovoltaic-thermal heat pump system;

[0098] Judge whether the increase in compressor power consumption is less than the total gain of the photovoltaic-thermal heat pump system;

[0099] When it is determined to be yes, increase the refrigerant flow rate of the first branch to make the increase in compressor power consumption and the total gain of the photovoltaic-thermal heat pump system equal.

[0100] Please refer to Figure 2 , which is the overall control flowchart of the photovoltaic-thermal heat pump system of the present invention. This appendix Figure 2Here, “component” represents the photovoltaic thermal component mentioned above, “dB” represents the total gain of the photovoltaic thermal heat pump system mentioned above, and “dQ” represents the increase in compressor power consumption mentioned above.

[0101] Should Figure 2 The flowchart corresponds to the control method of the photovoltaic thermal heat pump system in the above text, which first determines whether the current photovoltaic thermal heat pump system is working in the heating mode or the cooling mode;

[0102] If it is in heating mode, the working principle at this time is: absorb and utilize the waste heat of the components as the evaporator of the refrigeration cycle to achieve high energy efficiency heating, that is, "when the photovoltaic thermal heat pump system works in heating mode, the photovoltaic thermal components are used as evaporators, and the waste heat of the photovoltaic thermal components is used to heat the refrigerant" in the previous text;

[0103] If it is in cooling mode, the working principle at this time is: using the strong radiation heat dissipation capacity of the component as the condenser of the refrigeration cycle to achieve high-efficiency refrigeration, that is, "When the photovoltaic thermal heat pump system works in cooling mode, the photovoltaic thermal component is used as a condenser, and the radiation heat dissipation capacity of the photovoltaic thermal component is used to cool the refrigerant."

[0104] Then, in the heating mode, determine whether the component is generating electricity. If it is not generating electricity, it means that the heat dissipation effect of the component is good and it is not suitable to be used as an evaporator in the heating cycle at night, so maintain or reduce the flow of the branch where the component is located;

[0105] In cooling mode, determine whether the module generates electricity. If it does not generate electricity, it means that the module has a good heat dissipation effect at this time, and the module should be used as a condenser for the night refrigeration cycle. However, due to the large pressure drop of the module, the relationship between dB and dQ should still be examined;

[0106] Regardless of heating mode or cooling mode, when it is determined that the photovoltaic thermal module is in the power generation state, the module needs to be shielded. However, if the total gain brought by the reduction of module temperature is considered, the module branch flow should be adjusted and the relationship between dB and dQ should be examined;

[0107] Then determine whether dB>dQ, which is the aforementioned “determine whether the increase in compressor power consumption is less than the total gain of the photovoltaic thermal heat pump system”;

[0108] When the judgment is yes, the refrigerant flow rate of the component branch is maintained unchanged or reduced;

[0109] When the judgment is no, the refrigerant flow rate of the branch where the component is located is further increased and the component temperature is lowered (it can be maintained unchanged when it is below the threshold), which is the "increase the refrigerant flow rate of the first branch so that the increase in compressor power consumption is equal to the total gain of the photovoltaic thermal heat pump system" mentioned above.

[0110] In addition, if the energy efficiency of the photovoltaic thermal heat pump system is mainly considered (without paying attention to the total gain of the component itself), it is also necessary to adjust and distribute the flow of the refrigerant in the two branches (still through the first regulating valve and the refrigerant pump). The main factors are: 1. During the heating process, when the gain brought by the heat collection effect of the photovoltaic thermal component is not enough to cover its pressure drop energy loss, or 2. During the cooling process, when the gain brought by the heat dissipation effect of the photovoltaic thermal component is not enough to cover its pressure drop energy loss, the flow of the component cooling branch should be adjusted or reduced.

[0111] The gain brought by the heat collection effect during the heating process can be estimated by the heating cost of the air source heat pump under the same heating capacity. Similarly, the gain brought by the heat dissipation effect during the cooling process can be estimated by the cooling cost of the air source heat pump under the same heat dissipation capacity.

[0112] Based on the above design, the present invention also proposes an air conditioning system, which has the above photovoltaic thermal heat pump system.

[0113] In summary, compared with the prior art, the present invention has at least the following beneficial effects:

[0114] 1. The present invention is provided with a first regulating valve, a second regulating valve, and a refrigerant pump, which can reasonably distribute the refrigerant flow rate. When a large amount of heat absorption is required, more refrigerant can pass through the photovoltaic thermal component, and when a large amount of heat dissipation is required, more refrigerant can flow through the radiator, thereby reducing the energy consumption of the compressor under some working conditions;

[0115] 2. The present invention also detects the increase in compressor power consumption and the total gain of the photovoltaic thermal heat pump system, and when the photovoltaic thermal component is in the power generation state, adjusts the working point of the photovoltaic thermal heat pump system to make the increase in compressor power consumption and the total gain of the photovoltaic thermal heat pump system equal. Through this control, the photovoltaic thermal heat pump system can operate at the optimal energy efficiency working point to ensure the optimization of system energy efficiency.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A photovoltaic thermal heat pump system, characterized in that: It includes a main refrigerant flow path provided with a compressor, a first branch connected to the main refrigerant flow path and provided with a photovoltaic thermal component, and a second branch connected to the main refrigerant flow path and provided with a first heat exchanger; A first regulating valve is provided at the connection between the main refrigerant flow path and the first branch and the second branch, and the first regulating valve can distribute the ratio of the refrigerant in the main refrigerant flow path flowing into the first branch and the second branch.

2. The photovoltaic thermal heat pump system according to claim 1, characterized in that: It also includes a refrigerant pump arranged in the first branch and a second regulating valve arranged in the second branch. The refrigerant pump can adjust the flow rate of the refrigerant in the first branch, and the second regulating valve is used to adjust the resistance characteristics of the second branch.

3. The photovoltaic thermal heat pump system according to claim 2, characterized in that: Also included is a first sensor and a second sensor disposed in the first branch; The first sensor is located at the input side of the photovoltaic thermal assembly, and the second sensor is located at the output side of the photovoltaic thermal assembly; The first sensor and the second sensor are used to detect the physical state of the photovoltaic thermal component.

4. The photovoltaic thermal heat pump system according to claim 1, characterized in that: It also includes a third regulating valve disposed on the main refrigerant flow path, wherein the third regulating valve is connected to a refrigerant bypass, and the other side of the refrigerant bypass is connected to the first branch.

5. The photovoltaic thermal heat pump system according to claim 1, characterized in that: When the photovoltaic thermal heat pump system operates in a heating mode, the photovoltaic thermal component is used as an evaporator, and the first heat exchanger is configured as a condenser; When the photovoltaic thermal heat pump system operates in a cooling mode, the photovoltaic thermal component is used as a condenser, and the first heat exchanger is configured as an evaporator.

6. The photovoltaic thermal heat pump system according to claim 1, characterized in that: The main refrigerant flow path is also provided with a first throttle valve, a second throttle valve, and a second heat exchanger; The second heat exchanger serves as an input side of the main refrigerant flow path, and is used to receive the refrigerant returning from the first branch and the second branch; The first throttle valve is disposed between the compressor and the first regulating valve, and the second throttle valve is disposed between the compressor and the second heat exchanger.

7. The photovoltaic thermal heat pump system according to claim 3, characterized in that: The average temperature of the photovoltaic thermal assembly satisfies the calculation model: Tcell=f(Q,a,m1,m2,T1,T2,c,Tf,h) Among them, Q is the irradiance, a is the photoelectric conversion efficiency, T1 is the refrigerant temperature detected by the first sensor, T2 is the refrigerant temperature detected by the second sensor, m1 is the refrigerant flow detected by the first sensor, m2 is the refrigerant flow detected by the second sensor, c is the specific heat capacity of the refrigerant, Tf is the ambient temperature, h is the comprehensive heat transfer coefficient, and Tcell is the average temperature of the photovoltaic thermal component.

8. A control method for a photovoltaic thermal heat pump system according to any one of claims 1 to 7, characterized in that: include: Detecting the operating condition of the photovoltaic thermal heat pump system; When the photovoltaic thermal heat pump system works in a heating mode, the photovoltaic thermal component is used as an evaporator, and waste heat from the photovoltaic thermal component is used to heat the refrigerant; When the photovoltaic thermal heat pump system operates in a cooling mode, the photovoltaic thermal component is used as a condenser, and the radiation heat dissipation capacity of the photovoltaic thermal component is used to cool the refrigerant.

9. The control method of the photovoltaic thermal heat pump system according to claim 8, characterized in that: Also includes: When the photovoltaic thermal assembly is in a power generation state, detecting the increase in compressor power consumption and the total gain of the photovoltaic thermal heat pump system; Determining whether the increase in compressor power consumption is less than the total gain of the photovoltaic thermal heat pump system; When the judgment is yes, the refrigerant flow rate of the first branch is increased so that the increase in the power consumption of the compressor is equal to the total gain of the photovoltaic thermal heat pump system.

10. An air conditioning system, characterized in that: The air conditioning system has a photovoltaic thermal heat pump system as claimed in any one of claims 1 to 7.

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