Inter-seasonal series heat storage solar heating system and method based on heat shield principle

Abstract

The present invention discloses an inter-seasonal series heat storage solar heating system and method based on the heat shield principle, comprising a solar thermal collection and heating heat storage circuit, an inter-seasonal hot water storage tank heating circuit, a secondary heating circuit and a heat pump auxiliary heating circuit, and realizes inter-seasonal heat storage and winter heating by dynamically switching working modes, and simulates the constructed system with TRNSYS software, verifying the energy-saving advantage of the system compared with the boiler auxiliary heating system; the present invention arranges a high-temperature cylindrical hot water storage tank at the center of the heat storage system in series with a low-temperature concentric annular water tank on the outside, stores the hot water heated by the solar collector with a temperature gradient, and at the same time, the low-temperature annular water tank on the outside acts as a heat shield in space, which can greatly reduce heat storage losses, improve solar energy utilization, and provide a practical engineering technical solution for realizing green heating of buildings in winter.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar heating, and in particular relates to a cross-seasonal series heat storage solar heating system and method based on the heat shield principle. Background Art

[0002] In northern China, space heating energy consumption accounts for a large proportion of building energy consumption, and coal, natural gas and electricity are still the main forms of energy used for space heating. Northern China is rich in solar energy resources, so using solar energy to achieve clean building heating is an important way to help achieve the dual carbon goals as scheduled.

[0003] Solar energy not only has low energy density, but also has daily and seasonal fluctuations in solar radiation intensity, which is bound to lead to great defects in the stability of solar energy in space heating. In northern China, there is sufficient sunlight in the summer, but strong demand for heating in the winter, so equipping the solar heating system with a low-cost heat storage system is a key technical means to achieve the "summer storage and winter use" of solar energy and solve the seasonal mismatch between solar energy supply and demand.

[0004] Large-scale inter-seasonal underground heat storage tanks have been widely used in engineering practice due to their simple principle, low construction cost and high heat storage density per unit volume. However, large-scale inter-seasonal underground heat storage tanks also have the problem of large heat dissipation losses due to their large heat dissipation area and long heat storage time. In addition, in order to meet the heating demand, the heat storage temperature of the heat storage tank is generally designed to be high, which further aggravates the heat loss of the heat storage tank. Therefore, seeking a solar inter-seasonal heat storage heating system with high heat storage efficiency and low heat storage cost has strong engineering application value. Summary of the invention

[0005] In order to overcome the problem of large heat loss in cross-seasonal heat storage in the above-mentioned solar heating system, the present invention provides a cross-seasonal series heat storage solar heating system and method based on the principle of heat shield. The high-temperature cylindrical water storage tank at the center of the heat storage system is arranged in series with the low-temperature concentric annular water tank on the outside, so that the hot water heated by the solar collector is stored in a temperature gradient. At the same time, the low-temperature annular water tank on the outside acts as a heat shield in space, which can greatly reduce heat storage losses and improve solar energy utilization.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] An inter-seasonal series heat storage solar heating system based on the heat shield principle, which achieves inter-seasonal heat storage and winter heating by dynamically switching working modes, including a solar heat collection and heating storage circuit, an inter-seasonal hot water storage tank heating circuit, a secondary side heating circuit, and a heat pump auxiliary heating circuit;

[0008] The solar thermal heat collection and heat storage circuit includes a plate collector, an inter-seasonal hot water storage tank and a plate countercurrent heat exchanger. The outlet of the plate collector is connected to the inlet of the diverter valve three. The outlet working medium of the diverter valve three is selectively connected to the inlet one of the inter-seasonal hot water storage tank or the inlet of the plate countercurrent heat exchanger. The outlet one of the inter-seasonal hot water storage tank and the outlet of the plate countercurrent heat exchanger are connected to the inlet of the mixing valve one. The outlet of the mixing valve one is connected to the inlet of the plate collector after passing through the water supply pump one.

[0009] The inter-seasonal hot water storage tank heating circuit includes an inter-seasonal hot water storage tank and a plate countercurrent heat exchanger. The second outlet of the inter-seasonal hot water storage tank is connected to the second inlet of the diverter valve, and enters the plate countercurrent heat exchanger after passing through the mixing valve three and the water supply pump two. The outlet of the plate countercurrent heat exchanger is connected to the second inlet of the inter-seasonal hot water storage tank after passing through the diverter valve one; the primary and secondary side flows of the plate countercurrent heat exchanger are controlled by the second water supply pump and the fourth water supply pump;

[0010] The heat pump auxiliary heating circuit includes an inter-seasonal hot water storage tank, a buffer water tank, a photovoltaic panel and a water source heat pump. The second outlet of the inter-seasonal hot water storage tank is connected to the inlet of the second diverter valve, the outlet of the second diverter valve is connected to the inlet of the third water supply pump, the outlet of the third water supply pump is connected to the inlet of the heat source side of the water source heat pump, and the outlet of the heat source side of the water source heat pump is connected to the second inlet of the inter-seasonal hot water storage tank after passing through the second mixing valve and the first diverter valve; the second outlet of the buffer water tank is connected to the inlet of the load side of the water source heat pump after being diverted by the fourth diverter valve, the outlet of the load side of the water source heat pump is connected to the inlet of the fourth mixing valve, and the outlet of the fourth mixing valve is connected to the second inlet of the buffer water tank. The heat source side and load side circuits of the water source heat pump together constitute a secondary heating circuit, and the photovoltaic panel is used to provide power for the water source heat pump;

[0011] The secondary side heating circuit includes a buffer water tank, a mixing valve five, a temperature control valve and a user-side heat load. The buffer water tank outlet one located at the top of the buffer water tank and the temperature control valve outlet one are respectively connected to the two inlets of the mixing valve five. The outlet of the mixing valve five is connected to the user-side heat load through a water supply pump five for heating. The low-temperature return water after heating enters the temperature control valve, and the temperature control valve outlet two is connected to the buffer water tank inlet one.

[0012] A further improvement of the present invention is that the circulating working fluid in the process of the system is liquid water.

[0013] A further improvement of the present invention is that the inlet of the cross-seasonal water storage tank is arranged at the top of the inner cylindrical water storage tank, and the bottom of the inner cylindrical water storage tank is connected to the inlet of the top of the outer annular water storage tank through the internal connecting pipe of the water tank. The cross-seasonal water storage tank forms a temperature spatial position distribution in which the temperature of the cylindrical water storage tank in the center is higher and the temperature of the outer annular water storage tank is lower.

[0014] A further improvement of the present invention is that the outer annular heat storage tank acts as a heat shield in the cross-seasonal heat storage tank. According to the basic principles of heat transfer, the introduction of the heat shield adds two surface thermal resistances and one space thermal resistance to the original thermal resistance network diagram. When the emissivity of each surface is ε, the introduction of the heat shield will reduce the heat loss by nearly half.

[0015] A further improvement of the present invention is that the cylindrical water storage tank at the center of the cross-seasonal water storage tank and the outer annular water storage tank will automatically form thermal stratification, that is, the working fluid temperature in the upper part of the water tank is high, and the working fluid temperature in the lower part of the water tank is low.

[0016] A further improvement of the present invention is that the buffer water tank naturally forms thermal stratification due to the density difference of the working fluid, the working fluid with a higher temperature is located in the upper part of the buffer water tank, and the working fluid with a lower temperature is located in the lower part of the buffer water tank.

[0017] A further improvement of the present invention is that the data of the user-side heat load is obtained by simulation calculation using SketchUp and TRNSYS software according to the building structure.

[0018] A further improvement of the present invention is that the temperature control valve dynamically adjusts the flow distribution according to the top temperature of the buffer water tank and the heating return water temperature to ensure that the heating temperature is basically stable at the heating temperature set value.

[0019] A cross-seasonal series heat storage solar heating method based on the heat shielding plate principle, the method is based on the cross-seasonal series heat storage solar heating system based on the heat shielding plate principle, comprising:

[0020] In the non-heating season, when the difference between the collector outlet water temperature and the top temperature of the hot water storage tank is greater than or equal to 10°C, the feed pump 1 starts running, the diverter valve 3 opens the outlet 1, and the plate collector stores heat to the inter-seasonal hot water storage tank. When the top temperature of the central cylindrical hot water storage tank of the inter-seasonal hot water storage tank reaches 90°C, the diverter valve 3 opens the outlet 2, the feed pump 2 and the feed pump 4 start running, and the plate collector stores heat to the buffer water tank; when the difference between the collector outlet water temperature and the top temperature of the hot water storage tank is less than 10°C, the feed pump 1 stops running;

[0021] In the heating season, when the solar normal radiation intensity is greater than the winter set value and the temperature difference between the plate collector outlet water temperature and the top of the buffer water tank is greater than 10°C, feed water pump 2 and feed water pump 4 are turned on, and the plate collector supplies heat to the buffer water tank through the plate countercurrent heat exchanger, and the system is in direct heating mode; when the solar normal radiation intensity is greater than the winter set value and the temperature difference between the plate collector outlet water temperature and the top of the buffer water tank is less than or equal to 10°C, feed water pump 1 runs, diverter valve 3 opens outlet 1, and the plate collector stores heat in the cross-seasonal hot water storage tank; when the solar normal radiation intensity is less than or equal to the winter set value, if the temperature at the top of the buffer water tank is greater than or equal to 65°C, the temperature control valve and feed water pump 5 start running, and the system The system is in the buffer water tank heating mode; when the solar normal radiation intensity is less than or equal to the winter set value, if the temperature at the top of the buffer water tank is less than 65°C and the temperature difference between the top of the inter-seasonal hot water storage tank and the top of the buffer water tank is greater than or equal to 10°C, diverter valve two opens outlet two, and water supply pump two starts running, and the system is in the inter-seasonal hot water storage tank heating mode; when the solar normal radiation intensity is less than or equal to the winter set value, if the temperature at the top of the buffer water tank is less than 65°C and the temperature difference between the top of the inter-seasonal hot water storage tank and the top of the buffer water tank is less than 10°C, diverter valve two opens, diverter valve one opens, water supply pump three, water supply pump five and water supply pump six start running, and the system is in the water source heat pump heating mode.

[0022] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0023] The present invention provides a cross-seasonal series heat storage solar heating system based on the heat shield principle, which couples solar heat collection, cross-season heat storage and water source heat pump as the heat source for winter heating, ensuring the reliability of green energy heating in winter. Through the dynamic control of the diverter valve, mixing valve, temperature control valve and water supply pump in the system, intelligent switching of multiple operating modes is realized, solving the problem of mismatch between seasonal energy supply and demand in traditional solar heating systems.

[0024] The inter-seasonal heat storage based on the heat shield principle proposed in the present invention uses the high-temperature cylindrical water storage tank in the center as the primary heat storage carrier, and the low-temperature concentric annular water tank on the outside as the secondary heat storage carrier. The temperature gradient storage of the heat storage medium is cleverly achieved through the series arrangement of the two. At the same time, the annular water tank on the outside can play the role of a heat shield in terms of spatial position, thereby reducing inter-seasonal heat storage losses and solving the problem of low inter-seasonal heat storage efficiency of solar heating.

[0025] The cross-seasonal series heat storage solar heating method based on the heat shield principle provided by the present invention adopts advanced temperature difference control for the start and stop of the collector and the heat pump, that is, the heat collector pump starts to run when the difference between the outlet water temperature of the collector and the top temperature of the hot water storage tank is greater than or equal to 10°C, and stops running when it is less than 5°C. The start and stop control principle of the heat pump is similar to that of the collector. The above temperature difference control can not only effectively suppress the system volatility on the basis of ensuring the heat collection and heating effects, but also reduce the start and stop times of the heat collector pump and the heat pump, and improve the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural block diagram of the system of the present invention.

[0027] Figure 2 This is a schematic diagram of the structure of a cross-seasonal hot water storage tank.

[0028] Figure 3 Schematic diagram of the inlet and outlet of the buffer water tank.

[0029] Figure 4 It is the simulation interface for boiler auxiliary solar heating system.

[0030] Figure 5 Simulation interface for heat pump assisted solar heating system.

[0031] Figure 6 This is the simulation result diagram of the total energy consumption of the boiler-assisted solar heating system.

[0032] Figure 7 This is the simulation result diagram of the total energy consumption of the heat pump assisted solar heating system.

[0033] Description of reference numerals:

[0034] 1 is a plate collector, 2 is an inter-seasonal hot water storage tank, 3 is a diverter valve three, 4 is a water supply pump three, 5 is a mixing valve three, 6 is a mixing valve four, 7 is a buffer water tank, 8 is a photovoltaic panel, 9 is a water source heat pump, 10 is a water supply pump five, 11 is a water supply pump six, 12 is a user-side heat load, 13 is a mixing valve five, 14 is a temperature control valve, 15 is a diverter valve four, 16 is a water supply pump four, 17 is a plate countercurrent heat exchanger, 18 is a water supply pump two, 19 is a mixing valve two, 20 is a diverter valve two, 21 is a diverter valve one, 22 is a mixing valve one, and 23 is a water supply pump one.

[0035] 2-1 is the inlet 1 of the cross-seasonal hot water storage tank, 2-2 is the outlet 1 of the cross-seasonal hot water storage tank, 2-3 is the inlet 2 of the cross-seasonal hot water storage tank, 2-4 is the outlet 2 of the cross-seasonal hot water storage tank, 2-5 is the central high-temperature cylindrical cross-seasonal hot water storage tank, 2-6 is the low-temperature annular cross-seasonal hot water storage tank, 2-7 is the internal connecting pipe of the water tank, and 2-8 is the inner and outer water tank reinforcement ribs.

[0036] 7-1 is the buffer water tank outlet 1, 7-2 is the buffer water tank inlet 1, 7-3 is the buffer water tank outlet 2, and 7-4 is the buffer water tank inlet 2. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings, and the contents thereof are intended to explain the present invention rather than to limit it.

[0038] like Figure 1 As shown: the present invention consists of four circuits, namely a solar thermal collection and heating storage circuit, a cross-seasonal hot water storage tank heating circuit, a secondary side heating circuit and a heat pump auxiliary heating circuit. The four circuits operate in coordination to complete the dynamic switching of multiple working modes.

[0039] The high-temperature water heated by the plate collector 1 in the solar thermal heat collection and heat storage circuit is connected to the inlet of the diverter valve 3, and the diverter valve 3 can selectively open the outlet 1 or the outlet 2 according to the control signal. In the inter-seasonal hot water storage tank heat storage mode, the diverter valve three 3 opens outlet one and is connected to the inter-seasonal hot water storage tank inlet one 2-1. At this time, the inter-seasonal hot water storage tank outlet one 2-2 is opened and connected to the inlet of the mixing valve one 22. The water at the outlet of the mixing valve one 22 is pressurized by the water supply pump one 23 and enters the plate collector 1 for circulation heating; in the solar direct heating mode, the diverter valve three 3 opens outlet two and is connected to the mixing valve three 5. After being pressurized by the water supply pump two 18, it enters the plate countercurrent heat exchanger 17 to complete the heating of the water inside the buffer water tank 7. The outlet of the plate countercurrent heat exchanger 17 enters the diverter valve one 21 after passing through the mixing valve two 19. At this time, the diverter valve one 21 opens valve two and is connected to the mixing valve one 22. After being pressurized by the water supply pump one 23, it enters the plate collector 1 for circulation heating.

[0040] In the inter-seasonal hot water storage tank heating circuit, outlet 2-4 of the inter-seasonal hot water storage tank is connected to the inlet of diverter valve 20. At this time, diverter valve 20 opens outlet 2 and is connected to the inlet of mixing valve 3 5. The outlet of mixing valve 3 5 is connected to water supply pump 2 18. After pressurization, it enters plate countercurrent heat exchanger 17 to complete the heating of the water inside buffer water tank 7. The outlet of plate countercurrent heat exchanger 17 is connected to the inlet of diverter valve 1 21 after passing through mixing valve 2 19. The low-temperature water after heating returns to the bottom of the inter-seasonal hot water storage tank 2 via outlet 1 of diverter valve 21.

[0041] The high-temperature water in the upper layer of the buffer water tank 7 in the secondary heating circuit enters the mixing valve 13 from the buffer water tank outlet 7-1 to mix with the heating return water, and enters the user-side heat load 12 for heating after reaching the heating temperature set by the temperature control valve 14. After the heating, the low-temperature return water flows through the temperature control valve 14, and a part of it enters the buffer water tank 7 through the outlet 1 of the temperature control valve 14, and the other part is connected to the inlet of the mixing valve 13 through the outlet 2 of the temperature control valve 14 for direct winter heating.

[0042] In the heat pump auxiliary heating circuit, the high-temperature water at the top of the inter-seasonal hot water storage tank 2 enters the diverter valve 20 through the inter-seasonal hot water storage tank outlet 2-4, and the outlet of the diverter valve 20 is connected to the inlet of the water supply pump 3 4. After being pressurized by the water supply pump 3 4, it enters the heat source side of the water source heat pump 9. After the high-temperature water completes heating in the water source heat pump 9, it returns to the inter-seasonal hot water storage tank 2 through the mixing valve 2 19 and the diverter valve 1 21; the high-temperature water at the top of the buffer water tank 7 enters the diverter valve 4 15 through the buffer water tank outlet 2 7-3, and enters the load side of the water source heat pump 9 after diversion. The high-temperature water after absorbing heat and heating in the water source heat pump 9 returns to the buffer water tank 7 through the buffer water tank inlet 2 7-4 after the mixing valve 4 6 for secondary side heating.

[0043] As a preferred embodiment of the present invention, the plate collector 1 determines the heat collection area and installation angle according to the "Technical Specifications for Solar Energy Heating".

[0044] As a preferred embodiment of the present invention, the cross-seasonal heat storage tank 2 and the buffer water tank 7 have good temperature stratification, high-temperature water enters from the top inlet, and low-temperature water enters from the bottom inlet, and the temperature stratification is not destroyed when switching between multiple working modes.

[0045] As a preferred embodiment of the present invention, the water supply pumps are all variable frequency pumps, which can perform variable flow control according to control signals.

[0046] As a preferred embodiment of the present invention, the photovoltaic panel 8 is connected to an energy storage battery pack, and the energy storage battery pack is connected to the water source heat pump 9.

[0047] As a preferred embodiment of the present invention, the water source heat pump 9 is connected to an external power supply to provide power to the water source heat pump 9 when the power of the energy storage battery group is insufficient, thereby ensuring winter heating.

[0048] As a preferred embodiment of the present invention, the water storage capacity of the cross-seasonal hot water storage tank 2 is 3500m 3 , the burial depth is 1.5m.

[0049] As a preferred embodiment of the present invention, the plate-type collector 1 and the photovoltaic panel 8 are both provided with an azimuth angle adjustment mechanism and a pitch angle adjustment mechanism.

[0050] As a preferred embodiment of the present invention, the high-temperature cylindrical water storage tank 2-5 at the center and the low-temperature concentric annular water tank 2-6 at the outside are both covered with insulation layers on the top and sides.

[0051] As a preferred embodiment of the present invention, the high-temperature cylindrical water storage tank 2-5 at the center and the low-temperature concentric annular water tank 2-6 at the outside are both provided with 5 temperature sensors in the height direction, and the collected temperature data are used as input signals of the control system.

[0052] As a preferred embodiment of the present invention, the operating flow rates of the primary and secondary sides of the plate counterflow heat exchanger 17 can be adjusted accordingly according to the specific engineering application conditions. At the same time, in order to ensure the heat exchange efficiency of the heat exchanger, the heat exchange temperature difference between the primary and secondary sides should be greater than 10°C.

[0053] The above-mentioned inter-seasonal series heat storage solar heating system based on the heat shield principle includes the following working modes:

[0054] Summer heat storage mode: The high-temperature water heated by the plate collector 1 is connected to the inlet of the diverter valve 3, and the diverter valve 3 can selectively open the outlet 1 or outlet 2 according to the control signal. 2 ) and the top temperature of the inter-seasonal hot water storage tank 2 is less than the set value, the diverter valve three 3 opens outlet one and is connected to the inlet 2-1 of the inter-seasonal hot water storage tank. At this time, the outlet 2-2 of the inter-seasonal hot water storage tank is opened and connected to the inlet of the mixing valve 22. The water at the outlet of the mixing valve 22 is pressurized by the water supply pump 23 and enters the plate collector 1 for circulating heating. The system operates in the heat storage mode of the inter-seasonal hot water storage tank; when the normal solar radiation intensity is greater than the set value and the top temperature of the inter-seasonal hot water storage tank 2 is greater than or equal to the set value, the diverter valve three 3 opens outlet two, the water supply pump two 18 and the water supply pump four 16 start to run, and the solar thermal collection system stores heat to the buffer water tank.

[0055] Winter heating mode: When the solar normal radiation intensity is greater than the winter setting value (600W / m 2 ) and the temperature difference between the outlet water temperature of the plate collector 1 and the top temperature of the buffer water tank 7 is greater than 10°C, the feed water pump 2 18 and the feed water pump 4 16 are turned on to drive the working medium flow and heat exchange on the primary and secondary sides of the plate countercurrent heat exchanger 17. At this time, the plate collector 1 supplies heat to the buffer water tank 7 through the plate countercurrent heat exchanger 17, and the system is in direct heating mode; when the solar normal radiation intensity is greater than the winter setting value (600W / m 2 ) and the temperature difference between the outlet water temperature of the plate collector 1 and the top temperature of the buffer water tank 7 is less than or equal to 10°C, the water pump starts to operate, the diverter valve 3 opens the outlet 1, and the plate collector 1 stores heat in the inter-seasonal hot water storage tank 2; when the solar normal radiation intensity is less than or equal to the winter setting value (600W / m 2 ), if the top temperature of the buffer water tank 7 is greater than or equal to 65°C, the temperature control valve 14 and the water supply pump 10 start to operate, and the system is in the buffer water tank heating mode; when the solar normal radiation intensity is less than or equal to the winter setting value (600W / m 2), if the top temperature of the buffer water tank 7 is less than 65°C and the temperature difference between the top temperature of the inter-seasonal hot water storage tank 2 and the top temperature of the buffer water tank 7 is greater than or equal to 10°C, the diverter valve 20 opens the outlet 2, and the feed water pump 2 18 and the feed water pump 4 16 start to run, driving the plate countercurrent heat exchanger 17 to flow and exchange heat on the primary and secondary sides of the working medium, and the system is in the inter-seasonal hot water storage tank heating mode; when the solar normal radiation intensity is less than or equal to the winter setting value (600W / m 2 ), if the top temperature of the buffer water tank 7 is less than 65°C and the temperature difference between the top temperature of the inter-seasonal hot water storage tank 2 and the top temperature of the buffer water tank 7 is less than 10°C, the diverter valve 20 is opened, the diverter valve 1 21 is opened, the water supply pump 3 4, the water supply pump 5 10 and the water supply pump 6 11 start running, and the system is in the water source heat pump heating mode.

[0056] See also Figure 4 and Figure 5 Through TRNSYS simulation software, a solar cross-seasonal heat storage boiler auxiliary heating system model and a solar cross-seasonal heat storage heat pump auxiliary heating system model were built. Under the above advanced temperature difference control strategy, a 3000m 2 Heating simulation of the building.

[0057] See also Figure 6 and Figure 7 Under the same building heat load and control strategy, the monthly energy consumption of using heat pump as auxiliary heat source for winter heating is lower than that of boiler auxiliary heating. In the first year of system operation, compared with the solar inter-seasonal heat storage boiler auxiliary heating system, the cumulative energy consumption of this system is reduced by 141248kWh, saving 61% energy.

[0058] The description of the above embodiments is to facilitate those skilled in the art to fully understand and use the invention. Those skilled in the art can obviously make various modifications to the above embodiments and apply the general principles of this description to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A cross-seasonal series heat storage solar heating method based on the heat shield principle, characterized in that: The method is based on a cross-seasonal series heat storage solar heating system based on the principle of heat shielding plates. The system realizes cross-seasonal heat storage and winter heating by dynamically switching working modes, including a solar heat collection and heating storage circuit, a cross-seasonal hot water storage tank heating circuit, a secondary side heating circuit and a heat pump auxiliary heating circuit. The solar thermal heat collection and heat storage circuit includes a plate collector, an inter-seasonal hot water storage tank and a plate countercurrent heat exchanger. The outlet of the plate collector is connected to the inlet of the diverter valve three. The outlet working medium of the diverter valve three is selectively connected to the inlet one of the inter-seasonal hot water storage tank or the inlet of the plate countercurrent heat exchanger. The outlet one of the inter-seasonal hot water storage tank and the outlet of the plate countercurrent heat exchanger are connected to the inlet of the mixing valve one. The outlet of the mixing valve one is connected to the inlet of the plate collector after passing through the water supply pump one. The inter-seasonal hot water storage tank heating circuit includes an inter-seasonal hot water storage tank and a plate countercurrent heat exchanger. The second outlet of the inter-seasonal hot water storage tank is connected to the second inlet of the diverter valve, and enters the plate countercurrent heat exchanger after passing through the mixing valve three and the water supply pump two. The outlet of the plate countercurrent heat exchanger is connected to the second inlet of the inter-seasonal hot water storage tank after passing through the diverter valve one; the primary and secondary side flows of the plate countercurrent heat exchanger are controlled by the second water supply pump and the fourth water supply pump; The heat pump auxiliary heating circuit includes an inter-seasonal hot water storage tank, a buffer water tank, a photovoltaic panel and a water source heat pump. The second outlet of the inter-seasonal hot water storage tank is connected to the inlet of the second diverter valve, the outlet of the second diverter valve is connected to the inlet of the third water supply pump, the outlet of the third water supply pump is connected to the inlet of the heat source side of the water source heat pump, and the outlet of the heat source side of the water source heat pump is connected to the second inlet of the inter-seasonal hot water storage tank after passing through the second mixing valve and the first diverter valve; the second outlet of the buffer water tank is connected to the inlet of the load side of the water source heat pump after being diverted by the fourth diverter valve, the outlet of the load side of the water source heat pump is connected to the inlet of the fourth mixing valve, and the outlet of the fourth mixing valve is connected to the second inlet of the buffer water tank. The heat source side and load side circuits of the water source heat pump together constitute a secondary heating circuit, and the photovoltaic panel is used to provide power for the water source heat pump; The secondary heating circuit includes a buffer water tank, a mixing valve five, a temperature control valve and a user-side heat load. The buffer water tank outlet one located at the top of the buffer water tank and the temperature control valve outlet one are respectively connected to the two inlets of the mixing valve five. The outlet of the mixing valve five is connected to the user-side heat load through the water supply pump five for heating. The low-temperature return water after heating enters the temperature control valve. The temperature control valve outlet two is connected to the buffer water tank inlet one. The inlet of the cross-seasonal hot water storage tank is arranged at the top of the inner cylindrical hot water storage tank, and the bottom of the inner cylindrical hot water storage tank is connected to the inlet of the top of the outer annular hot water storage tank through the internal connecting pipe of the water tank, so that the cross-seasonal hot water storage tank forms a temperature spatial position distribution in which the temperature of the central cylindrical hot water storage tank is higher and the temperature of the outer annular hot water storage tank is lower; The outer annular heat storage tank acts as a heat shield in the inter-seasonal heat storage tank. According to the basic principle of heat transfer, the introduction of the heat shield adds two surface thermal resistances and one space thermal resistance to the original thermal resistance network diagram. When the emissivity of each surface is ε, the introduction of the heat shield will reduce the heat loss by nearly half. The method includes: In the non-heating season, when the difference between the collector outlet water temperature and the top temperature of the hot water storage tank is greater than or equal to 10 ℃, the feed pump 1 starts running, the diverter valve 3 opens the outlet 1, and the plate collector stores heat to the inter-seasonal hot water storage tank. When the top temperature of the central cylindrical hot water storage tank of the inter-seasonal hot water storage tank reaches 90 ℃, the diverter valve 3 opens the outlet 2, the feed pump 2 and the feed pump 4 start running, and the plate collector stores heat to the buffer water tank; when the difference between the collector outlet water temperature and the top temperature of the hot water storage tank is less than 10 ℃, the feed pump 1 stops running; In the heating season, when the solar normal radiation intensity is greater than the winter set value and the temperature difference between the plate collector outlet water temperature and the top of the buffer water tank is greater than 10 ℃, feed pump 2 and feed pump 4 are turned on, and the plate collector supplies heat to the buffer water tank through the plate countercurrent heat exchanger, and the system is in direct heating mode; when the solar normal radiation intensity is greater than the winter set value and the temperature difference between the plate collector outlet water temperature and the top of the buffer water tank is less than or equal to 10 ℃, feed pump 1 is running, diverter valve 3 opens outlet 1, and the plate collector stores heat in the inter-seasonal hot water storage tank; when the solar normal radiation intensity is less than or equal to the winter set value, if the temperature at the top of the buffer water tank is greater than or equal to 65 ℃, the temperature control valve and feed pump 5 start to operate, and the system is in the buffer water tank heating mode; when the solar normal radiation intensity is less than or equal to the winter set value, if the temperature at the top of the buffer water tank is less than 65 ℃ and the temperature difference between the top of the inter-seasonal hot water storage tank and the top of the buffer water tank is greater than or equal to 10 ℃, diverter valve two opens outlet two, and water supply pump two starts running at the same time, and the system is in the inter-seasonal hot water storage tank heating mode; when the solar normal radiation intensity is less than or equal to the winter set value, if the top temperature of the buffer water tank is less than 65 ℃ and the temperature difference between the top temperature of the inter-seasonal hot water storage tank and the top temperature of the buffer water tank is less than 10 ℃, diverter valve two opens, diverter valve one opens, water supply pump three, water supply pump five and water supply pump six start running, and the system is in the water source heat pump heating mode.

2. The cross-seasonal series heat storage solar heating method based on the heat shield principle according to claim 1 is characterized in that: The circulating working fluid in this system process is liquid water.

3. The cross-seasonal series heat storage solar heating method based on the heat shield principle according to claim 1 is characterized in that: The cylindrical water storage tank at the center of the cross-seasonal water storage tank and the outer annular water storage tank will automatically form thermal stratification, that is, the working fluid temperature at the upper part of the water tank is high, and the working fluid temperature at the lower part of the water tank is low.

4. The cross-seasonal series heat storage solar heating method based on the heat shield principle according to claim 1 is characterized in that: The buffer water tank naturally forms thermal stratification due to the density difference of the working fluid, the working fluid with a higher temperature is located in the upper part of the buffer water tank, and the working fluid with a lower temperature is located in the lower part of the buffer water tank.

5. The cross-seasonal series heat storage solar heating method based on the heat shield principle according to claim 1 is characterized in that: The user-side heat load data is obtained by simulation calculation using SketchUp software according to the building structure.

6. The cross-seasonal series heat storage solar heating method based on the heat shield principle according to claim 1 is characterized in that: The user-side heat load data is obtained by simulation calculation using TRNSYS software according to the building structure.

7. The cross-seasonal series heat storage solar heating method based on the heat shield principle according to claim 1 is characterized in that: The temperature control valve dynamically adjusts the flow distribution according to the top temperature of the buffer water tank and the heating return water temperature to ensure that the heating temperature is basically stable at the heating temperature set value.

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