PV / T coupling ground source heat pump heat supply method

Abstract

The invention provides a PV / T coupling ground source heat pump heat supply method. The PV / T coupling ground source heat pump heat supply method comprises the steps that heat supply is achieved for users through a PV / T efficient coupling ground source heat pump heat supply system; the system comprises a heat storage water tank, a ground source heat pump unit, a ground heat exchanger, an electric heating device and a liquid storage tank, the method comprises the steps that the temperature of a heat storage water tank is detected, the user side circulating water trend and / or the ground source side circulating water trend of the ground source heat pump unit side are / is determined according to the temperature of the heat storage water tank, and heating of the user side is achieved according to the user side circulating water trend and / or the ground source side circulating water trend. According to the method provided by the invention, the energy consumption of the ground source heat pump unit can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive utilization of ground source heat pumps and solar photovoltaic and thermal energy, and in particular to a PV / T coupled ground source heat pump heating method. Background Art

[0002] With the continuous development of clean energy technology, single ground source heat pump technology and solar energy technology have gradually matured. However, the use of a single heat source is often limited by certain climatic conditions. An important optimization method is to use the technology of coupling solar photovoltaic thermal system and ground source heat pump system to form a solar photovoltaic thermal-ground source heat pump coupling system to improve the system energy efficiency.

[0003] However, the solar photovoltaic-ground source heat pump coupling system still has the problem of low energy utilization during the actual coupling process and operation. Summary of the invention

[0004] The present invention provides a PV / T coupled ground source heat pump heating method to solve the problem of low energy utilization rate of the current solar photovoltaic thermal-ground source heat pump coupling system during the actual coupling process and operation process.

[0005] A PV / T coupled ground source heat pump heating method, comprising:

[0006] Use PV / T coupled ground source heat pump heating system to provide heating for users; the system includes: PVT photovoltaic thermal panels, hot water storage tanks, ground source heat pump units, buried pipe heat exchangers, electric heating devices, and liquid storage tanks;

[0007] The PV / T photovoltaic thermal panel is connected to the hot water storage tank through a pipeline to form a first circulation loop; the tap water pipeline on the user side passes through the hot water storage tank;

[0008] One side of the ground source heat pump unit is connected to the buried pipe heat exchanger through a ground source side circulating water pipeline to form a second circulation loop, and the other side thereof is connected to the indoor energy supply terminal through a user side circulating water pipeline to form a third circulation loop; a fourth circulation loop is arranged on the third circulation loop, and a part of the fourth circulation loop is arranged in the hot water storage tank;

[0009] The method includes:

[0010] Detect the temperature of the hot water storage tank and, based on the temperature of the hot water storage tank, determine whether to open or close the corresponding circulation loop to achieve heating.

[0011] Furthermore, in the PV / T coupled ground source heat pump heating method as described above, the detecting the temperature of the hot water storage tank and determining to open or close the corresponding circulation loop according to the temperature of the hot water storage tank to achieve heating includes:

[0012] The temperature of the hot water storage tank is detected. When the temperature of the hot water storage tank is within a first preset temperature range, the second circulation loop and the third circulation loop are closed; the first circulation loop and the fourth circulation loop are opened at the same time; the first circulation loop is used to provide heat energy for the hot water storage tank; at the same time, the circulating water in the fourth circulation loop is used to indirectly exchange heat with the hot water storage tank, and then the circulating water after heat exchange is supplied to the user side for heating.

[0013] Furthermore, in the PV / T coupled ground source heat pump heating method as described above, the detecting the temperature of the hot water storage tank and determining to open or close the corresponding circulation loop according to the temperature T2 of the hot water storage tank to achieve heating includes:

[0014] Detecting the temperature of the hot water storage tank, and when the temperature of the hot water storage tank is within a second preset temperature range, opening the first circulation loop, the second circulation loop, and the third circulation loop, and closing the fourth circulation loop;

[0015] and determining the temperature difference between the temperature T2 of the hot water storage tank and the outlet water temperature T3 of the buried pipe heat exchanger. When T2-T3 is greater than or equal to the first threshold, the circulating water in the second circulation loop is firstly indirectly heat-exchanged with the hot water storage tank, and then the circulating water on the ground source side after the heat exchange is heated to the target temperature by the ground source heat pump unit, and finally the user side is heated by the third circulation loop;

[0016] The temperature value of the second preset temperature range is lower than the temperature value of the first preset temperature range.

[0017] Further, in the PV / T coupled ground source heat pump heating method as described above, when T2-T3 is less than the first threshold, firstly, the PVT photovoltaic thermal panel is used to provide heat energy to the hot water storage tank; then, the temperature difference between the temperature T1 of the circulating medium flowing out of the outlet of the PVT photovoltaic thermal panel and the temperature T2 of the hot water storage tank is determined;

[0018] When T1-T2 is greater than or equal to the second threshold, it is determined whether T2-T3 is greater than or equal to the first threshold, and based on the temperature difference between T2 and T3, it is determined whether the circulating water in the second circulation loop first passes through the hot water storage tank for indirect heat exchange.

[0019] Furthermore, in the PV / T coupled ground source heat pump heating method as described above, when the PVT photovoltaic thermal panel provides thermal energy for the water storage tank, if T1-T2 is less than the second threshold, the water storage tank is heated by an electric heating device so that T1-T2 is greater than or equal to the second threshold; the electric energy of the electric heating device comes from the electric energy generated by the PVT photovoltaic thermal panel. When the electric energy generated by the PVT photovoltaic thermal panel is insufficient, the electric energy is provided to it by the power grid.

[0020] Furthermore, in the PV / T coupled ground source heat pump heating method as described above, the detecting the temperature of the hot water storage tank and determining to open or close the corresponding circulation loop according to the temperature of the hot water storage tank to achieve heating includes:

[0021] Detect the temperature of the hot water storage tank. When the temperature T2 of the hot water storage tank is ≥80°C, recycle the circulating medium in the first circulation loop into the liquid storage tank. At the same time, ensure that the PVT photovoltaic thermal panel only generates electricity without transmitting heat to the outside, close the fourth circulation loop, and open the second and third circulation loops. Absorb heat from the ground through the second circulation loop, and reheat the circulating medium to the target temperature through the ground source heat pump unit, and provide heat to users through the third circulation loop.

[0022] Furthermore, in the PV / T coupled ground source heat pump heating method as described above, the detecting the temperature of the hot water storage tank and determining to open or close the corresponding circulation loop according to the temperature of the hot water storage tank to achieve heating includes:

[0023] In the non-heating season, the temperature of the water storage tank is detected. When the temperature T2 of the water storage tank is less than 80°C, the heat generated by the PVT photovoltaic thermal panel is first sent to the water storage tank, and then the circulating water on the ground source side is sent to the water storage tank through the ground source heat pump unit for indirect heat exchange, and the circulating water on the ground source side after heat exchange is sent to the buried pipe heat exchanger to supplement the heat of the soil; the electric energy consumed by the ground source heat pump unit comes from the electric energy generated by the PVT photovoltaic thermal panel.

[0024] Further, in the PV / T coupled ground source heat pump heating method as described above, the first preset temperature range of the hot water storage tank is: 50±5°C≤T2<80°C;

[0025] Furthermore, in the PV / T coupled ground source heat pump heating method as described above, the second preset temperature range of the hot water storage tank is T2<50±5℃; and the first threshold is 3℃.

[0026] Furthermore, in the PV / T coupled ground source heat pump heating method as described above, the second threshold is 3°C.

[0027] The PV / T coupled ground source heat pump heating method provided by the present invention determines the direction of circulating water on the user side and / or the direction of circulating water on the ground source side of the ground source heat pump unit by the temperature of the hot water storage tank, and realizes heating to the user side according to the direction of circulating water on the user side and / or the direction of circulating water on the ground source side. Compared with directly heating the circulating water on the user side to the target temperature, the method provided by the present invention effectively reduces the energy consumption of the ground source heat pump unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1A schematic diagram of a PV / T high-efficiency coupled ground-source heat pump heating system provided by the present invention;

[0029] Reference numerals:

[0030] 1-PVT photovoltaic thermal panel, 2-heat storage tank, 3-ground source heat pump unit, 4-underground pipe heat exchanger, 5-electric heating device, 6-liquid storage tank, 7-inverter, 8-bidirectional electric meter, 9-household appliances, 10-power grid, 11-indoor energy supply terminal, B1-first circulation pump, B2-second circulation pump, B3-third circulation pump, B4-fourth circulation pump, T1-first thermometer, T2-second thermometer, T3-third thermometer, F1-first solenoid valve, F2-second solenoid valve, F3-third solenoid valve, F4-first three-way valve, F5-second three-way valve, F6-fourth solenoid valve, F7-fifth solenoid valve. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of 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.

[0032] The method provided by the present invention is mainly used to effectively reduce the energy consumption of a ground source heat pump unit during the heating season.

[0033] Figure 1 The schematic diagram of the PV / T high-efficiency coupled ground source heat pump heating system provided by the present invention is as follows: Figure 1 As shown, the system includes: PVT photovoltaic thermal panel 1, hot water storage tank 2, ground source heat pump unit 3, buried pipe heat exchanger 4, electric heating device 5, liquid storage tank 6, inverter 7, bidirectional electric meter 8, household appliances 9, power grid 10, indoor energy supply terminal 11, first circulation pump B1, second circulation pump B2, third circulation pump B3, fourth circulation pump B4, first thermometer T1, second thermometer T2, first solenoid valve F1, second solenoid valve F2, third solenoid valve F3, fourth solenoid valve F6, fifth solenoid valve F7, first three-way valve F4, second three-way valve F5.

[0034] Specifically, the hot water storage tank 2 is used to heat tap water, user-side circulating water or ground source-side circulating water; the ground source heat pump unit 3 exchanges heat with the outside through two heat exchange loops; wherein the third circulation loop or the fourth circulation loop is connected to the user's indoor energy supply terminal 11 for heating or cooling the user; the second circulation loop is connected to the buried pipe heat exchanger 4 for absorbing or dissipating heat from the soil; the electric energy of the electric heating device 5 preferably comes from the electric energy generated by the PVT photovoltaic thermal panel 1; when the electric energy generated by the PVT photovoltaic thermal panel 1 is insufficient, the power grid 10 provides it with electric energy. The PVT photovoltaic thermal panel, i.e., the solar photovoltaic / thermal (PV / T) collector, combines the photovoltaic effect and the photothermal effect, and can generate electric energy and thermal energy at the same time, thereby achieving a higher utilization rate of solar energy. Its working principle is: using the photovoltaic effect of sunlight to generate electricity, and using the thermal effect of sunlight to heat the heat transfer medium (such as water or air), thereby improving the heat collection efficiency. It combines photovoltaic panels and collectors organically, takes away the generated heat in time through the medium, controls the working temperature of solar cells, enables them to provide electricity more efficiently, and the heat taken away is also effectively utilized. For example: PVT photovoltaic thermal panels are used to form a PV / T energy supply system. The PV / T energy supply system refers to the use of PV / T solar photovoltaic thermal panels to provide heat energy on the one hand, which is stored in the hot water storage tank 2, and on the other hand, to provide electricity for the local heat pump unit 3 and the pump system in the coupling system. Excess photovoltaic power generation adopts the form of surplus power grid access. The heat generated by the PV / T photovoltaic thermal panel is directly connected to the hot water storage tank 2 through the circulating medium.

[0035] The ground source heat pump unit 2 is also called the geothermal heat pump unit or the ground source heat pump air conditioning system. It uses ground source energy (soil, groundwater, surface water, low-temperature geothermal water and tail water) as the cooling source for heat pump cooling in summer and the low-temperature heat source for heating in winter. It is also a system for heating, cooling and domestic hot water. Its working principle is based on the Carnot cycle and reverse Carnot cycle principles of the heat pump. By inputting a small amount of high-quality energy (such as electricity), it realizes the transfer of energy from the low-temperature heat source to the high-temperature heat source. The ground source heat pump unit is mainly composed of components such as a compressor, an evaporator, a condenser and an expansion valve. When the ground source heat pump unit is in operation, it does not consume water or pollute water, does not require equipment such as boilers and cooling towers, and does not produce emissions. It is pollution-free to the environment and is an energy-saving and environmentally friendly "green air conditioner".

[0036] A heat storage pipe is arranged inside the hot water storage tank 2, and the heat storage pipe is connected to the circulating water pipe arranged on the ground source heat pump unit 3; the ground pipe heat exchanger 4 is connected to the ground source side circulating water pipe arranged on the ground source heat pump unit 3; the electric energy of the electric heating device 5 is preferentially derived from the electric energy generated by the PVT photovoltaic thermal panel 1; when the electric energy generated by the PVT photovoltaic thermal panel 1 is insufficient, the electric energy is provided to it through the power grid 10; the circulating medium flowing out of the hot water storage tank 2 is divided into two branches, and the two branches are respectively connected to the hot water storage tank 2; one branch is directly connected to the hot water storage tank 2 through the first circulating pump B1; and the other branch is connected to the hot water storage tank 2 through the liquid storage tank 6. The PV / T photovoltaic thermal panel 1 is connected to the hot water storage tank 2 through the pipe to form a first circulation loop; one side of the ground source heat pump unit 3 is connected to the ground pipe heat exchanger 4 through the ground source side circulating water pipe to form a second circulation loop, and the other side thereof is connected to the indoor energy supply terminal 11 through the user side circulating water pipe to form a third circulation loop; a second circulation pump B2 is arranged on the second circulation loop. A fourth circulation loop is also connected in parallel to the third circulation loop, a part of which is arranged in the hot water storage tank 2, a fourth circulation pump B4 is arranged on the third circulation loop, and a third circulation pump B3 is arranged on the fourth circulation loop. In winter: the circulating medium flowing out of the ground source heat pump unit 3 supplies energy to the user through the fourth circulation pump B4; in summer, the circulating medium flowing out of the ground source heat pump unit 3 supplies heat to the soil through the second circulation pump B2.

[0037] The present invention provides a PV / T coupled ground source heat pump heating method, comprising:

[0038] The temperature of the hot water storage tank 2 is detected, and according to the temperature T2 of the hot water storage tank 2, it is determined whether to open or close the corresponding circulation loop to realize heating.

[0039] Specifically, the circulating water on both sides of the geothermal heat pump unit 3 is: user-side circulating water and geothermal-side circulating water. Among them, the user-side circulating water is the circulating water supplied to the user side for heating; the geothermal-side circulating water is the circulating water that is preliminarily heated by geothermal energy (soil, groundwater, surface water, low-temperature geothermal water and tail water). After being heated by the geothermal heat pump unit 3, the circulating water becomes the user-side circulating water for heating the user.

[0040] Since the circulating water for heating the user side can only provide heating for the user when it reaches a standard temperature or above, when the circulating water temperature is below the standard temperature, it needs to be reheated by the ground source heat pump unit 3, thereby consuming electric energy. The purpose of the present invention is to detect the temperature of the hot water storage tank 2 and determine to open or close the corresponding circulation loop according to the temperature T2 of the hot water storage tank 2, so as to provide heat energy for the user or provide heat energy for the soil.

[0041] The PV / T coupled ground source heat pump heating method provided by the present invention determines whether to open or close the corresponding circulation loop by the temperature of the hot water storage tank to achieve heating, thereby effectively reducing the energy consumption of the ground source heat pump unit 3.

[0042] Further, the following provides a method for determining to open or close a corresponding circulation loop according to the temperature T2 of the hot water storage tank to achieve heating, specifically including:

[0043] The temperature of the hot water storage tank 2 is detected. When the temperature T2 of the hot water storage tank 2 is within the first preset temperature range, the second circulation loop and the third circulation loop are closed; the first circulation loop and the fourth circulation loop are opened at the same time; the first circulation loop is used to provide heat energy for the hot water storage tank 2; at the same time, the circulating water in the fourth circulation loop is used to indirectly exchange heat with the hot water storage tank 2, and then the user-side circulating water after heat exchange is supplied to the user side for heating.

[0044] Specifically, Figure 1 As shown, the ground source side circulating water is the circulating water on the left side of the ground source heat pump unit 3, and the user side circulating water is the circulating water on the right side of the ground source heat pump unit 3. In the embodiment of the present invention, if the user side circulating water is directly heated to the target temperature for heating the user side, the energy consumption of the ground source heat pump unit 3 will be greatly increased. In order to reduce energy consumption, the present invention uses the fourth circulation loop to pass the user side circulating water through the hot water storage tank 2 for indirect heat exchange, and then detects whether the user side circulating water after heat exchange reaches the target temperature. If the target temperature is reached, the user is directly heated through the fourth circulation loop; if the corresponding target temperature is not reached, the user side circulating water needs to be heated to the target temperature through the ground source heat pump unit 3 to heat the user side. However, if the temperature of the hot water storage tank 2 is low, there is no need for indirect heat exchange. Therefore, the present invention needs to first detect whether the temperature T2 of the hot water storage tank 2 is within the first preset temperature range. If it is within the first preset temperature range, it means that the temperature of the hot water storage tank 2 can meet the heating needs. At this time, the third circulation pump B3, the first three-way valve F4, and the second three-way valve F5 are turned on to directly heat the user side through the fourth circulation loop, that is, the circulating water in the fourth circulation loop directly heats the indoor energy supply terminal 11 after indirect heat exchange through the hot water storage tank 2. Therefore, there is no need to pass through the third circulation loop, so that the ground source heat pump unit 3 does not need to consume energy and can achieve the purpose of heating the user, thereby reducing the energy consumption of the ground source heat pump unit 3. In addition, a third circulation pump B3 is also provided on the fourth circulation loop, and the third circulation pump B3 is powered by the PVT photovoltaic thermal panel 1, thereby further reducing the energy consumption of the entire system.

[0045] The PV / T coupled ground source heat pump heating method provided by the present invention first detects whether the temperature of the hot water storage tank meets the first preset temperature range. If it meets the first preset temperature range, the fourth circulation loop is used to heat the user, thereby effectively reducing the energy consumption of the ground source heat pump unit 3. Moreover, if the inlet water temperature of the ground source heat pump unit 3 is too high or too low, the ground source heat pump will start and stop frequently and malfunction frequently. In order to solve this problem, the present invention firstly provides heating for the user through the fourth circulation loop, thereby avoiding the frequent start and stop caused by the inlet water temperature of the ground source heat pump unit 3 being too high or too low, which not only reduces the energy consumption of the ground source heat pump unit 3, but also increases the life of the ground source heat pump unit 3.

[0046] Furthermore, the first preset temperature range of the hot water storage tank 2 is: 50±5°C≤T2<80°C.

[0047] Specifically, when the temperature of the hot water storage tank 2 is 50±5℃≤T2<80℃, the temperature of the hot water storage tank 2 can fully achieve the purpose of indirectly heating the circulating water on the user side to the target temperature, thereby avoiding the phenomenon that the ground source heat pump unit heats the circulating water on the user side. Therefore, the energy consumption of the ground source heat pump unit 3 is greatly reduced, and there is even no need to consume the energy consumption of the ground source heat pump unit 3.

[0048] Furthermore, the present invention also provides a method for determining to open or close a corresponding circulation loop according to the temperature T2 of the hot water storage tank 2 to achieve heating, comprising:

[0049] Detect the temperature of the hot water storage tank 2. When the temperature T2 of the hot water storage tank 2 is within the second preset temperature range, open the first circulation loop, the second circulation loop, and the third circulation loop, and close the fourth circulation loop; and determine the temperature difference between the temperature T2 of the hot water storage tank 2 and the outlet water temperature T3 of the buried pipe heat exchanger 4. When T2-T3 is greater than or equal to the first threshold, the circulating water in the second circulation loop is first indirectly heat-exchanged with the hot water storage tank 2, and then the circulating water on the ground source side after heat exchange is heated to the target temperature through the ground source heat pump unit 3, and finally the third circulation loop is used to heat the user side. Among them, the temperature value of the second preset temperature range is less than the temperature value of the first preset temperature range.

[0050] Specifically, when the temperature T2 of the hot water storage tank 2 is within the second preset temperature range, the temperature of the hot water storage tank 2 is insufficient to provide indirect heat exchange energy for the user-side circulating water. Therefore, the third circulating pump B3, the first three-way valve F4, and the second three-way valve F5 on the fourth circulating loop are closed, and the first circulating loop, the second circulating loop, and the third circulating loop are opened. If the ground source side circulating water is directly heated to the target temperature through the ground source heat pump unit 3 and then used as the user-side circulating water for heating the user side, the energy consumption of the ground source heat pump unit 3 is too high. In order to solve this problem, the present invention first exchanges heat between the ground source side circulating water and the buried pipe heat exchanger 4 through the second circulating loop to increase the temperature of the ground source side circulating water. When the temperature T2 of the hot water storage tank 2 is within the second preset temperature range, although the user-side circulating water cannot be directly heated to the target temperature through the fourth circulation loop for heating the user, if the temperature T2 of the hot water storage tank 2 is still higher than the outlet water temperature T3 of the detected ground pipe heat exchanger 4, then it is necessary to pass the ground source side circulating water after heat exchange through the ground pipe heat exchanger 4 through the hot water storage tank 2 again for indirect heat exchange, and then heat the ground source side circulating water after heat exchange to the target temperature through the ground source heat pump unit 3, so as to form user-side circulating water for heating the user side, and can also effectively reduce the temperature of the ground source heat pump unit 3. Therefore, the present invention first compares the temperature difference between the temperature T2 of the hot water storage tank 2 and the outlet water temperature T3 of the buried pipe heat exchanger 4. When T2-T3 is greater than or equal to the first threshold, the second circulation pump B2 and the fifth solenoid valve F7 on the second circulation loop are turned on, and the third solenoid valve F3 is closed at the same time, so that the circulating water on the ground source side first exchanges heat indirectly with the hot water storage tank 2, and then the circulating water on the ground source side after heat exchange is heated to the target temperature through the ground source heat pump unit 3, and finally used as the user side circulating water to provide heating for the user side.

[0051] The PV / T coupled ground source heat pump heating method provided by the present invention first performs indirect heat exchange between the ground source side circulating water and the water storage tank when T2-T3 is greater than or equal to the first threshold value, and then heats the ground source side circulating water after heat exchange to the target temperature through the ground source heat pump unit, thereby achieving the purpose of reducing the energy consumption of the ground source heat pump unit.

[0052] Furthermore, the second preset temperature range is T2<50±5°C, and the first threshold is 3°C.

[0053] The present invention can reduce the energy consumption of the ground source heat pump unit to the greatest extent by setting the second preset temperature range to T2<50°C±5°C and the first threshold to 3°C.

[0054] Due to the energy usage habits of different regions and different users, the lower limit value of the first preset temperature and the upper limit value of the second preset temperature of the present invention can be adjusted within the range of ±5°C.

[0055] Further, when it is detected that the temperature T2 of the hot water storage tank 2 is within the second preset temperature range and T2-T3 is less than the first threshold, the PVT photovoltaic thermal panel 1 is first used to provide thermal energy to the hot water storage tank 2; then the temperature difference between the temperature T1 of the circulating medium flowing out of the outlet of the PVT photovoltaic thermal panel 1 and the temperature T2 of the hot water storage tank 2 is determined; when T1-T2 is greater than or equal to the second threshold, it is determined whether T2-T3 is greater than or equal to the first threshold, and based on the temperature difference between T2 and T3, it is determined whether the circulating water in the second circulation loop first passes through the hot water storage tank 2 for indirect heat exchange.

[0056] Specifically, when it is detected that the temperature T2 of the hot water storage tank 2 is within the second preset temperature range and T2-T3 is less than the first threshold, the second circulation pump B2 and the third solenoid valve F3 on the second circulation loop are turned on, and the fifth solenoid valve F7 is closed at the same time, and the PVT photovoltaic thermal panel 1 is used to provide heat energy for the hot water storage tank 2, and then the temperature difference between the temperature T1 of the circulating medium flowing out of the outlet of the PVT photovoltaic thermal panel 1 and the temperature T2 of the hot water storage tank 2 is judged. When T1-T2 is greater than or equal to the second threshold, the first circulation pump B1 and the third solenoid valve F3 on the first circulation loop are turned on. The fourth solenoid valve F6 closes the second solenoid valve F2, so that the circulating medium of the PVT photovoltaic thermal panel 1 forms a cycle between the PVT photovoltaic thermal panel 1 and the water storage tank 2, and continuously provides heat energy to the water storage tank 2 until the temperature difference between the temperature T2 of the water storage tank 2 and the temperature T3 of the circulating medium flowing out of the buried pipe heat exchanger 4 is greater than or equal to 3°C. The circulating water on the ground source side is first indirectly heat exchanged with the water storage tank 2, and then the circulating water on the ground source side after heat exchange is heated to the target temperature through the ground source heat pump unit 3, and finally the user side is heated through the third circulation loop.

[0057] The method provided by the present invention first utilizes the PVT photovoltaic thermal panel to heat the water storage tank, and then utilizes the water storage tank to indirectly exchange heat with the circulating water on the ground source side. Since the heat energy supplied by the PVT photovoltaic thermal panel to the water storage tank comes from solar energy, the temperature of the circulating water on the ground source side is indirectly exchanged. Therefore, it is avoided that the ground source heat pump unit 3 directly heats the circulating water on the ground source side coming out of the buried pipe heat exchanger 4 to the target temperature, thereby reducing the energy consumption of the ground source heat pump unit 3.

[0058] Furthermore, when the PVT photovoltaic thermal panel 1 provides thermal energy for the water storage tank 2, if T1-T2 is less than the second threshold, the water storage tank 2 is heated by the electric heating device 5 so that T1-T2 is greater than or equal to the second threshold; the electric energy of the electric heating device 5 comes from the electric energy generated by the PVT photovoltaic thermal panel 1. When the electric energy generated by the PVT photovoltaic thermal panel 1 is insufficient, the power grid 10 provides electric energy thereto.

[0059] Specifically, when it is detected that the temperature T2 of the hot water storage tank 2 is within the second preset temperature range, and the temperature difference between the temperature T2 of the hot water storage tank 2 and the temperature T2-T3 of the ground source side circulating water flowing out of the ground pipe heat exchanger 4 is less than the first threshold value, the PVT photovoltaic thermal panel 1 provides heat energy to the hot water storage tank 2. When the PVT photovoltaic thermal panel 1 provides heat energy to the hot water storage tank 2, the temperature difference between the PVT photovoltaic thermal panel 1 and the hot water storage tank 2 is still less than the second threshold value, and the first circulation pump B1, the fourth solenoid valve F6, and the second solenoid valve F2 on the first circulation loop are closed to stop the circulation of the circulating medium of the PVT photovoltaic thermal panel 1. At the same time, the hot water storage tank 2 is provided with heat energy by the electric heating device 5 until the hot water storage tank 2 can realize indirect heat exchange for the ground source side circulating water flowing out of the ground pipe heat exchanger 4, wherein the electric energy of the electric heating device 5 that provides heat energy to the hot water storage tank 2 comes from the electric energy generated by the PVT photovoltaic thermal panel 1.

[0060] In the method provided by the present invention, since the electric energy of the electric heating device 5 comes from the electric energy generated by the PVT photovoltaic thermal panel 1, and the electric energy generated by the PVT photovoltaic thermal panel 1 comes from photovoltaic energy, the ground source side circulating water flowing out of the buried pipe heat exchanger 4 can be indirectly heat exchanged through the water storage tank, thereby avoiding the phenomenon that the ground source heat pump unit 3 directly heats the ground source side circulating water coming out of the buried pipe heat exchanger 4 to the target temperature, thereby reducing the energy consumption of the ground source heat pump unit 3.

[0061] Furthermore, the second threshold corresponding to the temperature difference between the PVT photovoltaic thermal panel 1 and the hot water storage tank 2 is 3°C.

[0062] The method provided by the present invention can reduce the energy consumption of the ground source heat pump unit 3 to the greatest extent by controlling the second threshold value at 3°C.

[0063] Furthermore, the method provided by the present invention determines to open or close the corresponding circulation loop according to the temperature T2 of the hot water storage tank 2 based on the detected temperature of the hot water storage tank 2 to realize heating, and further includes:

[0064] Detect the temperature of the hot water storage tank 2. When the temperature T2 of the hot water storage tank 2 is ≥80°C, recycle the circulating medium in the first circulation loop to the liquid storage tank 6. At the same time, ensure that the PVT photovoltaic thermal panel 1 only generates electricity without transmitting heat to the outside, close the fourth circulation loop, and open the second and third circulation loops. Absorb heat from the ground through the second circulation loop, and reheat the circulating medium after absorbing heat to the target temperature through the ground source heat pump unit 3, and provide heat to users through the third circulation loop.

[0065] Specifically, when the temperature T2 of the hot water storage tank 2 is detected to be ≥80°C, the circulating medium flowing between the PVT photovoltaic thermal panel 1 and the hot water storage tank 2 will leak due to the expansion of the antifreeze in the circulating medium due to the heat due to the high temperature; and the equipment will be corroded due to the high temperature. In order to avoid these problems, the PV / T antifreeze recovery system is turned on, that is, the first circulation pump B1 and the second solenoid valve F2 are turned on, and the fourth solenoid valve F6 is closed at the same time. All the circulating medium in the hot water storage tank 2 is temporarily stored in the liquid storage tank 6. At this time, the PVT photovoltaic thermal panel 1 only generates electricity without transmitting heat to the outside; only when the temperature meets the condition that the circulating medium does not leak, the circulating medium is refilled into the hot water storage tank. At this time, the PVT photovoltaic thermal panel 1 generates electricity and transmits heat to the outside at the same time.

[0066] The method provided by the present invention solves the problem of leakage of the circulating medium of the PVT photovoltaic thermal panel due to volume expansion caused by heating under high temperature conditions, and also solves the problem of corrosion of the corresponding equipment.

[0067] Furthermore, the method of detecting the temperature of the hot water storage tank 2 provided by the present invention and determining to open or close the corresponding circulation loop according to the temperature T2 of the hot water storage tank 2 to realize heating also includes:

[0068] In the non-heating season, the temperature of the water storage tank 2 is detected. When the temperature T2 of the water storage tank 2 is less than 80°C, the heat generated by the PVT photovoltaic thermal panel 1 is first sent to the water storage tank 2, and then the ground source side circulating water is sent to the water storage tank 2 through the ground source heat pump unit 3 for indirect heat exchange, and the ground source side circulating water after heat exchange is sent to the buried pipe heat exchanger 4 to supplement the soil; the electric energy consumed by the ground source heat pump unit 3 comes from the electric energy generated by the PVT photovoltaic thermal panel 1.

[0069] Specifically, the heat exchange capacity of geothermal buried pipes has been reduced year by year during continuous operation for many years. Using heat without supplementary heat will inevitably cause the temperature of the soil source to gradually decrease. The method provided by the present invention is to send the heat generated by the PVT photovoltaic thermal panel 1 to the water storage tank 2 in the non-heating season, and the circulating water on the ground source side and the water storage tank 2 first undergo indirect heat exchange before entering the buried pipe heat exchanger 4 for supplementary heat; at the same time, the PVT photovoltaic thermal panel 1 generates electricity to provide electricity for the ground source heat pump unit 3, thereby achieving the effect of non-powered supplementary heat operation of the system in the non-heating season.

[0070] Furthermore, the present invention can also detect the temperature of the hot water storage tank 2. When the temperature T2 of the hot water storage tank 2 is ≤30°C, the electric heating device 5 provides thermal energy to the hot water storage tank 2, and then the hot water storage tank 2 performs indirect heat exchange on the tap water to realize the supply of domestic hot water.

[0071] Specifically, the user's domestic hot water is hot water supplied to the user after the tap water and the water storage tank reach the standard temperature of domestic hot water through indirect heat exchange. Therefore, the present invention sets a thermometer inside the water storage tank. When the temperature is less than or equal to 30°C, the electric heating device 5 is automatically turned on to heat the water storage tank 2, and then the first solenoid valve F1 is turned on to achieve indirect heat exchange between the tap water and the water storage tank.

[0072] The method provided by the present invention realizes cascaded energy use and improves energy efficiency in view of the characteristics of solar energy as an unstable energy source and the energy use habits of users, and has high feasibility. In addition, the method comprehensively considers the disadvantages of the current use of solar thermal collectors and provides an antifreeze recovery method to avoid the problem of premature aging and retirement of the device caused by the waste of antifreeze due to spraying out under high temperature conditions, thereby extending the service life of the entire system and reducing the use cost.

[0073] 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 PV / T coupled ground source heat pump heating method, characterized in that: include: A PV / T coupled ground source heat pump heating system is used to provide heating for users; the system comprises: a PVT photovoltaic thermal panel (1), a hot water storage tank (2), a ground source heat pump unit (3), a buried pipe heat exchanger (4), an electric heating device (5), and a liquid storage tank (6); The PV / T photovoltaic thermal panel (1) is connected to the hot water storage tank (2) via a pipeline to form a first circulation loop; the tap water pipeline on the user side passes through the hot water storage tank (2); One side of the ground source heat pump unit (3) is connected to the ground pipe heat exchanger (4) via a ground source side circulating water pipeline to form a second circulation loop, and the other side thereof is connected to the indoor energy supply terminal (11) via a user side circulating water pipeline to form a third circulation loop; a fourth circulation loop is arranged on the third circulation loop, and a part of the fourth circulation loop is arranged in the hot water storage tank (2); The method includes: The temperature of the hot water storage tank (2) is detected, and according to the temperature of the hot water storage tank (2), it is determined whether to open or close the corresponding circulation loop to realize heating.

2. The PV / T coupled ground source heat pump heating method according to claim 1, characterized in that: The detecting the temperature of the hot water storage tank (2) and determining to open or close a corresponding circulation loop according to the temperature of the hot water storage tank (2) to achieve heat supply comprises: The temperature of the hot water storage tank (2) is detected, and when the temperature of the hot water storage tank (2) is within a first preset temperature range, the second circulation loop and the third circulation loop are closed; the first circulation loop and the fourth circulation loop are opened at the same time; the first circulation loop is used to provide thermal energy for the hot water storage tank (2); at the same time, the circulating water in the fourth circulation loop is used to indirectly exchange heat with the hot water storage tank (2), and then the circulating water after the heat exchange is supplied to the user side for heating.

3. The PV / T coupled ground source heat pump heating method according to claim 1, characterized in that: The detecting the temperature of the hot water storage tank (2) and determining to open or close a corresponding circulation loop according to the temperature of the hot water storage tank (2) to achieve heat supply comprises: Detecting the temperature of the hot water storage tank (2), and when the temperature of the hot water storage tank (2) is within a second preset temperature range, opening the first circulation loop, the second circulation loop, and the third circulation loop, and closing the fourth circulation loop; and determining the temperature difference between the temperature T2 of the hot water storage tank (2) and the outlet water temperature T3 of the buried pipe heat exchanger (4); and when T2-T3 is greater than or equal to a first threshold, firstly indirectly exchanging heat between the circulating water in the second circulation loop and the hot water storage tank (2); and then heating the circulating water on the ground source side after the heat exchange to a target temperature through the ground source heat pump unit (3); and finally heating the user side through the third circulation loop; The temperature value of the second preset temperature range is lower than the temperature value of the first preset temperature range.

4. The method according to claim 3, characterized in that When T2-T3 is less than the first threshold, firstly, the PVT photovoltaic thermal panel (1) provides thermal energy to the hot water storage tank (2); then, the temperature difference between the temperature T1 of the circulating medium flowing out of the outlet of the PVT photovoltaic thermal panel (1) and the temperature T2 of the hot water storage tank (2) is determined; When T1-T2 is greater than or equal to the second threshold, it is determined whether T2-T3 is greater than or equal to the first threshold, and based on the temperature difference between T2 and T3, it is determined whether the circulating water in the second circulation loop first passes through the hot water storage tank (2) for indirect heat exchange.

5. The method according to claim 4, characterized in that The method further comprises: when the PVT photovoltaic thermal panel (1) provides thermal energy for the water storage tank (2), if T1-T2 is less than the second threshold, heating the water storage tank (2) by means of an electric heating device (5) so that T1-T2 is greater than or equal to the second threshold; the electric energy of the electric heating device comes from the electric energy generated by the PVT photovoltaic thermal panel (1); when the electric energy generated by the PVT photovoltaic thermal panel (1) is insufficient, the electric energy is provided to the PVT photovoltaic thermal panel (1) by means of a power grid (10).

6. The method according to claim 1, characterized in that The detecting the temperature of the hot water storage tank (2) and determining to open or close a corresponding circulation loop according to the temperature of the hot water storage tank (2) to achieve heat supply comprises: The temperature of the hot water storage tank (2) is detected. When the temperature T2 of the hot water storage tank (2) is ≥80°C, the circulating medium in the first circulation loop is recovered into the liquid storage tank (6); at the same time, the PVT photovoltaic thermal panel (1) is ensured to only generate electricity without transmitting heat to the outside, and the fourth circulation loop is closed, and the second circulation loop and the third circulation loop are opened; heat is absorbed from the ground through the second circulation loop, and the circulating medium after absorbing heat is heated again to the target temperature through the ground source heat pump unit (3), and heat is provided to the user through the third circulation loop.

7. The method according to claim 1, characterized in that The detecting the temperature of the hot water storage tank (2) and determining to open or close a corresponding circulation loop according to the temperature of the hot water storage tank (2) to achieve heat supply comprises: In the non-heating season, the temperature of the water storage tank (2) is detected. When the temperature T2 of the water storage tank (2) is less than 80° C., the heat generated by the PVT photovoltaic thermal panel (1) is first sent to the water storage tank (2), and then the ground source side circulating water is sent to the water storage tank (2) through the ground source heat pump unit (3) for indirect heat exchange, and the ground source side circulating water after heat exchange is sent to the buried pipe heat exchanger (4) to supplement the soil heat; the electric energy consumed by the ground source heat pump unit (3) comes from the electric energy generated by the PVT photovoltaic thermal panel (1).

8. The method according to claim 2, characterized in that: The first preset temperature range of the hot water storage tank (2) is: 50±5°C≤T2<80°C.

9. The method according to claim 3, characterized in that: The second preset temperature range of the hot water storage tank (2) is T2<50±5°C; the first threshold value is 3°C.

10. The method according to claim 4, characterized in that The second threshold is 3°C.

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