Solar heating and radiation cooling building energy-saving system integrating cold storage and heat storage and control method

Abstract

The invention discloses a solar heating and radiation cooling building energy-saving system integrating cold storage and heat storage and a control method, the system comprises a hot-cold coupling conversion module, a heat storage container, a cold storage container, a heat exchange adjusting device and a control and switching unit, and the heat storage operation mode, the heat supply operation mode, the cold storage operation mode and the cold supply operation mode can be flexibly switched. According to the hot-cold coupling conversion module, independent and separated heating and cooling channels are constructed, an efficient nanofluid heat absorption medium and a multi-layer film radiation cooler are introduced, the functions of efficient solar energy absorption and atmospheric window wave band radiation emission are achieved, and synchronous management of heat energy and cold energy is achieved. According to the control method, loop switching, flow adjustment, temperature feedback and dynamic optimization control strategies are executed based on real-time environment parameters and indoor thermal load requirements, and switching and adjustment of the system under variable working conditions are ensured. The dynamic response and energy consumption optimization of the annual cooling and heating load of the building can be realized, and the adaptability, the stability and the energy-saving effect of the system are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of building energy conservation and renewable energy utilization, and relates to solar thermal utilization and passive radiative cooling technologies. Specifically, it is a solar heating and radiative cooling building energy conservation system integrated with cold and heat storage and a control method, which is used to achieve annual heating and cooling regulation of building spaces, improve energy utilization efficiency, and reduce operating energy consumption. Background Art

[0002] As two ways of utilizing renewable clean energy, solar heating and radiative cooling technologies have received extensive attention in the field of building energy conservation in recent years. Solar heating utilizes solar radiant energy and converts it into heat energy through a heat collection device for indoor heating or hot water supply. This technology has a relatively high maturity level, but it is usually limited by the diurnal cycle and seasonal variations, and there are intermittency and instability in heat energy utilization. Radiative cooling technology is a passive cooling method, especially in the far-infrared band. By using a high-emissivity surface material, heat is radiated into outer space in the form of radiation to achieve a cooling effect without power consumption. This technology has advantages such as zero energy consumption, no noise, and no pollution, and is particularly suitable for building cooling requirements in summer.

[0003] From the perspective of system integration, the solar heating system and the radiative cooling system are strongly complementary: the former is suitable for heat energy storage requirements in cold seasons or at night, and the latter is suitable for passive cooling requirements in hot seasons or during the day. To meet the dual needs of building heating and cooling throughout the year, some existing technologies have tried to integrate solar heating and radiative cooling functions in the same structure using spectrally tunable materials. Existing hybrid systems mainly achieve dual-function switching by adjusting the spectral selectivity of a single material (such as wet / dry states, color change / phase change, etc.), that is, by changing the absorptivity / emissivity of the material in the solar radiation band and the atmospheric window band to achieve heating and cooling functions. However, this solution has the following technical defects: First, it is difficult to achieve optimal performance in a single functional mode because a compromise needs to be made between heating and cooling performance; second, the function conversion is not convenient enough, usually requiring complex material modification or structural adjustment; third, there are challenges in long-term stable operation, and the material performance may decay over time. In addition, currently, the integrated solar heating and radiative cooling functions generally lack effective heat and cold energy storage mechanisms. The heating and cooling requirements of buildings not only involve seasonal variations but also short-term factors such as diurnal variations and weather changes. When facing complex working conditions such as diurnal temperature differences and weather fluctuations, the continuous operation ability and regulation performance of the system are limited, and it is difficult to achieve continuous regulation of the indoor temperature of the building.

[0004] For example, Chinese Patent CN211345922U discloses a winter and summer temperature regulation device based on radiative cooling and solar energy utilization. This device realizes the seasonal conversion of the heat absorption layer and the radiative cooling layer through a rotating structure, which is respectively used for heating in winter and cooling in summer, and has a certain seasonal adaptability. However, the function switching of this solution relies on mechanical rotation and flipping, with a complex structure, slow response speed, low control accuracy, and lack of an effective energy storage mechanism, making it difficult to meet the continuous regulation requirements of the building for heat / cold energy.

[0005] In summary, the existing technologies cannot achieve low-cost, fast-response dynamic switching between solar heating and radiative cooling while ensuring high performance in a single mode, and lack a cold storage and heat storage coordination mechanism to cope with the imbalance between energy supply and demand. Therefore, it is an urgent technical problem to develop a solar heating-radiative cooling building energy-saving system that integrates cold storage and heat storage, independent optimization of dual modes, and can operate continuously throughout the year. Summary of the Invention

[0006] (1) Objectives of the Invention

[0007] Aiming at the above-mentioned defects and deficiencies of the existing technologies, the present invention aims to provide a solar heating and radiative cooling building energy-saving system and a control method that integrate cold storage and heat storage. By constructing independent and separated heating and cooling channels, introducing highly efficient nanofluid heat absorption media and multi-layer film radiative coolers, and combining heat storage and cold storage units and a switching control module, the present invention realizes the efficient integration and flexible switching of solar heating and radiative cooling functions. Through a time-sharing operation strategy, the present invention respectively realizes solar heat absorption and heat storage under sunlight conditions, realizes passive cooling and cold storage under suitable radiative conditions, and accurately controls the supply air temperature based on a mass flow regulation strategy, thereby realizing the dynamic response of the building's annual heating and cooling loads and optimizing energy consumption, significantly improving the adaptability, stability, and energy-saving effect of the system.

[0008] (2) Technical Solutions

[0009] To achieve the objectives of the invention and solve its technical problems, the present invention adopts the following technical solutions:

[0010] The first objective of the present invention is to provide a solar heating and radiative cooling building energy-saving system that integrates cold storage and heat storage, which is used to realize the efficient switching and combined operation of solar heating and radiative cooling functions in a building space under different seasons and day-night conditions, so as to improve the annual building energy utilization efficiency and reduce the operation energy consumption. The system at least includes a thermal-cold coupling conversion module, a heat storage container, a cold storage container, a heat exchange regulation device, and a control and switching unit, wherein:

[0011] The thermo - cold coupling conversion module includes a top transparent cover plate, a radiative cooler, and a bottom support plate that are arranged at intervals from top to bottom in sequence. Among them: The transparent cover plate is arranged on the outermost layer of the module and is used to transmit solar radiation and reduce energy loss in the visible light band; A hot fluid channel is formed between the top transparent cover plate and the radiative cooler and is used to circulate a nanofluid medium with strong light absorption ability to absorb solar radiation energy in the solar heating mode; The radiative cooler includes multiple layers of thin films arranged in a stack and is integrally configured to have a high reflectivity in the solar spectrum range and a high emissivity in the 8 - 13μm atmospheric window wavelength range, and is used to radiate heat to outer space in the radiative cooling mode; A cold fluid channel is formed between the radiative cooler and the bottom support plate and is used to introduce a cold fluid medium in the radiative cooling mode, and release heat through the radiative cooler to achieve passive cooling.

[0012] The control and switching unit is used to realize the switching and adjustment of four operating modes: heat storage, heat supply, cold storage, and cold supply according to external environmental parameters and indoor heat load requirements. Among them: In the heat storage mode, the cold fluid channel is emptied, and the nanofluid medium absorbs solar radiation energy in the hot fluid channel and stores the thermal energy in the heat storage container; In the heat supply mode, the high - temperature nanofluid medium in the heat storage container heats the air through a heat exchange regulating device to achieve indoor heating; In the cold storage mode, the hot fluid channel is emptied, and the liquid cold fluid medium radiates heat through the radiative cooler in the cold fluid channel and stores the cold energy in the cold storage container; In the cold supply mode, the cooling air directly passes through the cold fluid channel, or the low - temperature liquid cold fluid medium in the cold storage container directly cools the air through a heat exchange regulating device to achieve indoor cold supply.

[0013] The second object of the present invention is to provide a control method for the above - mentioned integrated cold - storage and heat - storage solar heating and radiative cooling building energy - saving system, which at least includes the following steps:

[0014] SS1. Environmental parameter monitoring and operating mode judgment:

[0015] Real - time collect the solar radiation intensity, outdoor ambient temperature, indoor air temperature, heat storage container temperature, cold storage container temperature, and user - set target temperature, and based on the preset control logic, analyze the current environmental conditions and building heat load requirements to determine the operating mode that the system should adopt currently.

[0016] SS2. Initial state clearing of the loop and path preparation:

[0017] According to the determined operating mode, by coordinating the states of each three - way control valve, four - way control valve, circulation pump, and fan, clear the working fluid loop that does not participate in the operation currently, recover the hot fluid or cold fluid to the heat storage container or cold storage container respectively, and isolate the subsystem paths of non - current modes.

[0018] SS3. Fluid Path Construction and Circulation Establishment:

[0019] According to the determined operating mode, control the opening states of each three-way control valve and four-way control valve to reconfigure the fluid path. In the heat storage mode, empty the cold fluid channel and establish a circulation path between the hot fluid channel and the heat storage container. In the heat supply mode, connect the heat exchange loop between the heat storage container and the heat exchange and regulation device. In the cold storage mode, empty the hot fluid channel and establish a circulation path between the cold fluid channel and the cold storage container. In the cold supply mode, select the direct cooling or energy storage cooling path according to the radiative cooling conditions;

[0020] SS4. Regulation and Control of Fluid Delivery Equipment:

[0021] Start and adjust the operating frequencies of the selected circulation pumps and air delivery fans according to the current operating mode, control and regulate the mass flow rates of various fluids. Optimize the circulation rate of the nanofluid medium in the heat storage and heat supply modes to achieve the best solar absorption efficiency and heat exchange efficiency. In the cold storage and cold supply modes, adjust the cold fluid circulation rate and air flow rate to achieve the optimal radiative cooling effect and indoor temperature control;

[0022] SS5. Temperature Feedback and Dynamic Optimization:

[0023] Continuously monitor the temperature changes and energy efficiency indicators during the operation of the system. When it is detected that the indoor temperature deviates from the set target temperature, precisely control the supply air temperature by adjusting parameters such as the fluid mass flow rate, heat capacity flow ratio Rc, and number of transfer units Ntu. At the same time, dynamically optimize the operation strategy according to the energy balance equation and system performance evaluation indicators to ensure that the system can maintain efficient and stable operation and achieve the best energy-saving effect under different seasons and day-night conditions;

[0024] SS6. Mode Switching and Fault Tolerance Regulation:

[0025] Under the conditions of sudden changes in external working conditions or changes in user requirements, trigger the operation mode switching process, give priority to retaining the heat storage or cold storage energy of the system, and then execute the path configuration, valve switching, and circulation regulation under the new mode to ensure the stable and energy-saving operation of the system and its robustness.

[0026] (III) Technical Effects

[0027] Compared with the prior art, the integrated solar heating and radiative cooling building energy-saving system with cold and heat storage and its control method of the present invention have the following beneficial and remarkable technical effects: (1) By constructing a thermal-cooling coupling conversion module, the present invention integrates efficient solar heat absorption and radiative cooling functions that can work day and night, and combines the two-way energy storage mechanisms of the heat storage container and the cold storage container to achieve efficient switching and coordinated operation of the solar heating and radiative cooling functions of the building under different seasons, day and night, and climate conditions; the combination of nanofluids and multi-layer film radiative coolers in the system significantly improves the efficiency of heat / cold energy acquisition, greatly enhancing the low-carbon operation ability and annual adaptability of the building energy system. (2) By setting control valves, circulation pumps, fans, and an environmental monitoring and execution control module, the present invention constructs a control system with real-time response capabilities, which can adjust the operation mode and fluid flow according to parameters such as solar irradiance, indoor and outdoor temperatures, and user-set target temperatures, realizing dynamic switching and precise temperature control in the heat storage, heat supply, cold storage, and cold supply modes; effectively overcoming the problems of slow function switching, low adjustment accuracy, and high energy waste in traditional systems, and improving the stability, comfort, and energy-saving performance of the system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0029] Figure 1 The figure shows a schematic diagram of the integrated solar heating and radiative cooling building energy-saving system with cold and heat storage provided by the embodiment of the present invention;

[0030] Figure 2 The figure shows a schematic diagram of the structure of the thermal-cooling coupling conversion module in the present invention;

[0031] Figure 3 The figure shows a flowchart of the control method of the building energy-saving system of the present invention.

[0032] Figure 4 The figure shows a schematic diagram of the operation of the system of the present invention in the heat storage mode;

[0033] Figure 5 The figure shows a schematic diagram of the operation of the system in the heat supply mode (at night or under low irradiance conditions);

[0034] Figure 6 The figure shows a schematic diagram of the operation of the system in the heat supply mode (under high irradiance conditions during the day);

[0035] Figure 7 The figure shows a schematic diagram of the operation of the system of the present invention in the cold storage mode;

[0036] Figure 8 The figure shows a schematic diagram of the system operating in the cooling mode (with good working conditions for radiative cooling);

[0037] Figure 9 The figure shows a schematic diagram of the system operating in the cooling mode (with poor working conditions for radiative cooling).

[0038] Explanation of reference numerals:

[0039] Thermal - cold coupling conversion module 10, transparent cover plate 11, radiative cooler 12, bottom support plate 13, hot fluid channel 14, cold fluid channel 15, heat storage container 20, cold storage container 30, heat exchange regulation device 40, control and switching unit 50, first three - way control valve 51, second three - way control valve 52, third three - way control valve 53, fourth three - way control valve 54, fifth three - way control valve 55, four - way control valve 56, nanofluid circulation pump 57, liquid cold fluid circulation pump 58, air delivery fan 59. Detailed implementation manners

[0040] The present invention aims to provide an integrated heat storage and cold storage solar heating and radiative cooling building energy - saving system and control method, which is used to realize the efficient switching and combined operation of solar heating and radiative cooling functions in building spaces under different seasons and day - night conditions, so as to improve the annual building energy utilization efficiency and reduce the operation energy consumption. To make the purpose, technical solutions and advantages of the implementation of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, rather than all of the embodiments, and the described embodiments are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0041] Embodiment 1: Building energy - saving system

[0042] As a specific example, as Figure 1 shown, the integrated heat storage and cold storage solar heating and radiative cooling building energy - saving system provided by the embodiment of the present invention includes a thermal - cold coupling conversion module 10, a heat storage container 20, a cold storage container 30, a heat exchange regulation device 40, and a control and switching unit 50, wherein:

[0043] The thermal - cold coupling conversion module 10, as Figure 2As shown, it includes a top transparent cover plate 11, a radiative cooler 12, and a bottom support plate 13 that are arranged at intervals from top to bottom in sequence, where: The transparent cover plate 11 is arranged on the outermost layer of the module 10, and is used to transmit solar radiation and reduce energy loss in the visible light band; A thermal fluid channel 14 is formed between the top transparent cover plate 11 and the radiative cooler 12, and is used to circulate a nanofluid medium with strong light absorption ability to absorb solar radiation energy in the solar heating mode; The radiative cooler 12 includes multiple layers of thin films arranged in a stacked manner, and is integrally configured to have a high reflectivity in the solar spectrum range and a high emissivity in the 8 - 13μm atmospheric window wavelength range, and is used to radiate heat to outer space in the radiative cooling mode; A cold fluid channel 15 is formed between the radiative cooler 12 and the bottom support plate 13, and is used to introduce a cold fluid medium in the radiative cooling mode, and release heat through the radiative cooler to achieve passive cooling.

[0044] In the thermal - cold coupling conversion module 10, the nanofluid medium is a two - component nanofluid in which silver nanoparticles and graphene are compound - dispersed in deionized water. By controlling the nanoparticle concentration at about 100 ppm, its average transmittance in the 0.25 - 2.5μm solar spectrum range is not higher than 5%, and when its depth is 1 cm, its absorption rate of solar radiation reaches more than 99%. The nanofluid medium in the present invention is a nanofluid composed of tiny particles suspended in water. Since the suspended particles can greatly absorb and scatter sunlight, the sunlight absorption rate of the nanofluid is much higher than that of pure water, its thermal conductivity is increased by more than 15% compared with pure water, and its viscosity is increased by no more than 5%. It has both good fluidity and heat storage capacity, and has good photothermal stability and recyclability.

[0045] In addition, the radiative cooler 12 in the thermal - cold coupling conversion module 10 preferably adopts a six - layer thin - film structure, including MgF2, TiO2, MgF2, SiN, SiO2, and MgF2 layers arranged in a stacked manner from top to bottom in sequence. The thickness range of each layer of film is 0.3 - 3.0μm, and spectral design is carried out by the characteristic matrix method, so that the emissivity peak of the multi - layer film radiative cooler overlaps and matches the atmospheric transmittance in the 8 - 13μm atmospheric window band and the radiative emissivity is not lower than 94%, and the reflectivity in the 0.25 - 2.5μm solar spectrum range is not lower than 90%, realizing the radiative cooling ability that can operate day and night.

[0046] The heat exchange regulation device 40 in the present invention preferably adopts a counter - flow plate - type heat exchanger structure, and optimizes the heat exchange efficiency of the heat exchanger by adjusting the heat capacity flow ratio Rc and the number of heat transfer units Ntu between the nanofluid medium and air, where the NTU value is controlled at 2 - 8 and the Rc value is controlled at 0.2 - 1.5 to ensure that the heating / cooling air temperature meets the operating requirements in different seasons.

[0047] The control and switching unit 50 in the present invention is used to realize the switching and adjustment of the heat storage, heat supply, cold storage, and cold supply modes according to the external environmental parameters and the indoor heat load requirements. In the heat storage mode, the cold fluid channel 15 is emptied, and the nanofluid absorbs solar radiant energy in the hot fluid channel 14 and stores the thermal energy in the heat storage container 20; in the heat supply mode, the high-temperature nanofluid in the heat storage container 20 heats the air through the heat exchange adjustment device 40 to achieve indoor heating; in the cold storage mode, the hot fluid channel 15 is emptied, and the liquid cold fluid medium radiates heat through the radiation cooler 12 in the cold fluid channel 15 and stores the cold energy in the cold storage container 30; in the cold supply mode, the cooling air directly passes through the cold fluid channel 15 or the low-temperature liquid cold fluid medium in the cold storage container 30 cools the air through the heat exchange adjustment device 40 to achieve indoor cold supply.

[0048] Further, the control and switching unit includes a number of control valves. A first three-way control valve 51 is provided at the inlet end of the heat storage container 20, and a second three-way control valve 52 is provided at the outlet end; a four-way control valve 56 is provided at the inlet end of the medium heat exchange side of the heat exchange adjustment device, and a third three-way control valve 53 is provided at the outlet end; a fourth three-way control valve 54 is provided at the outlet end of the cold storage container 30; a fifth three-way control valve 55 is provided on the outlet pipeline of the air heat exchange side of the heat exchange adjustment device.

[0049] And among them, as Figure 1 shown, the inlet of the first three-way control valve 51 is communicated with the outlet of the hot fluid channel 14, the first outlet is communicated with the inlet of the heat storage container 20, and the second outlet is communicated with the first inlet of the second three-way control valve 52; the second inlet of the second three-way control valve 52 is communicated with the outlet of the heat storage container 20, and the outlet is communicated with the first inlet of the four-way control valve 56; the second inlet of the four-way control valve 56 is communicated with the outlet of the cold fluid channel 15, the first outlet is communicated with the inlet of the medium heat exchange side of the heat exchange adjustment device 40, and the second outlet is communicated with the first inlet of the fifth three-way control valve 55; the inlet of the third three-way control valve 53 is communicated with the outlet of the medium heat exchange side of the heat exchange adjustment device 40, the first outlet is communicated with the inlet of the hot fluid channel 14, and the second outlet is communicated with the inlet of the cold storage container 30; the first inlet of the fourth three-way control valve 54 is communicated with the outlet of the cold storage container 40, the second inlet is communicated with the air environment, and the outlet is communicated with the inlet of the cold fluid channel 15; the second inlet of the fifth three-way control valve 55 is communicated with the outlet of the air heat exchange side of the heat exchange adjustment device 40, and the outlet is communicated with the air environment; and the inlet of the air heat exchange side of the heat exchange adjustment device 40 is communicated with the air environment.

[0050] Further, a nanofluid circulation pump 57 is provided on the outlet pipeline of the hot fluid channel 14, which is used to drive the nanofluid medium to circulate between the hot fluid channel 14, the heat storage container 20 and the medium heat exchange side of the heat exchange and regulation device 40; a liquid cold fluid circulation pump 58 is provided on the inlet pipeline of the cold storage container 30, which is used to drive the liquid cold fluid medium to circulate between the cold fluid channel 15, the cold storage container 30 and the medium heat exchange side of the heat exchange and regulation device 40; an air delivery fan 59 is provided on the outlet pipeline of the fifth three-way control valve 55, which is used to drive air to pass through the air heat exchange side of the heat exchange and regulation device 40 or directly through the cold fluid channel 15; each circulation pump and fan are equipped with variable frequency speed regulation and real-time feedback interfaces, and cooperate with the control and switching unit 50 to adjust the mass flow rate of each fluid, so as to realize the dynamic control of the supply air temperature, response rate and the overall energy efficiency of the system.

[0051] Further, the control and switching unit 50 further includes an environmental monitoring module and an execution control module. The environmental monitoring module at least includes a plurality of sensors for monitoring and collecting solar radiation intensity, outdoor temperature, indoor temperature, heat storage temperature, cold storage temperature, supply air temperature, and the opening states of each control valve. Each sensor, control valve, circulation pump and air delivery fan are communicatively connected to the execution control module. The execution control module judges the current operating state based on the data collected by the environmental monitoring module and the target temperature or operating mode set by the user, and issues adjustment instructions through the built-in control logic to jointly control each control valve, each circulation pump and the fan in the system.

[0052] In summary, the integrated heat storage and cold storage solar heating and radiative cooling building energy-saving system of Embodiment 1 realizes the organic integration of solar heating and radiative cooling functions. Through the coordinated cooperation of the thermal and cold coupling conversion module, heat storage container, cold storage container, heat exchange and regulation device and control and switching unit, it effectively solves the problem of the mismatch between the intermittency of renewable energy and the building energy demand time, and provides a continuous, efficient and stable heating and cooling solution for the building throughout the year.

[0053] Embodiment 2: Control Method

[0054] Based on the hardware architecture and control valve configuration of the integrated heat storage and cold storage solar heating and radiative cooling building energy-saving system described in Embodiment 1, this Embodiment 2 further elaborates the intelligent control method of the system. Through key steps such as environmental parameter monitoring, fluid path reconstruction, and equipment coordinated regulation, it realizes the automatic switching and optimal control of four operating modes of heat storage, heat supply, cold storage and cold supply, and ensures that the system can maintain efficient and stable operation under different working conditions. As Figure 3 shown, the method includes the following steps when implemented:

[0055] SS1. Environmental parameter monitoring and operating mode judgment:

[0056] Collect the solar radiation intensity, outdoor ambient temperature, indoor air temperature, heat storage container temperature, cold storage container temperature, and the target temperature set by the user in real time. Analyze the current environmental conditions and the building heat load requirements based on the preset control logic to determine the operating mode that the system should adopt currently.

[0057] SS2. Initial state clearing of the loop and path preparation:

[0058] According to the determined operating mode, by coordinating the states of each three-way control valve, four-way control valve, circulation pump, and fan, clear the working fluid loops that are not currently participating in the operation, recover the hot fluid or cold fluid to the heat storage container or cold storage container respectively, and isolate the subsystem paths of non-current modes.

[0059] SS3. Fluid path construction and circulation establishment:

[0060] According to the determined operating mode, control the opening states of each three-way control valve and four-way control valve to reconfigure the fluid path. In the heat storage mode, clear the cold fluid channel and establish the circulation path between the hot fluid channel and the heat storage container. In the heating mode, connect the heat exchange loop between the heat storage container and the heat exchange and regulation device. In the cold storage mode, clear the hot fluid channel and establish the circulation path between the cold fluid channel and the cold storage container. In the cooling mode, select the direct cooling or energy storage cooling path according to the radiation cooling conditions.

[0061] SS4. Regulation and control of fluid conveying equipment:

[0062] Start and adjust the operating frequencies of the selected circulation pump and air delivery fan according to the current operating mode, control and adjust the mass flow rate of each fluid. Optimize the circulation rate of the nanofluid medium in the heat storage and heating modes to achieve the best solar energy absorption efficiency and heat exchange efficiency. In the cold storage and cooling modes, adjust the cold fluid circulation rate and air flow rate to achieve the optimal radiation cooling effect and indoor temperature control.

[0063] SS5. Temperature feedback and dynamic optimization:

[0064] Continuously monitor the temperature changes and energy efficiency indicators during the operation of the system. When it is detected that the indoor temperature deviates from the set target temperature, precisely control the supply air temperature by adjusting the fluid mass flow rate, heat capacity flow ratio Rc, and the number of transfer units Ntu parameters. At the same time, dynamically optimize the operation strategy according to the energy balance equation and the system performance evaluation index to ensure that the system can maintain efficient and stable operation under different seasons and day-night conditions and achieve the best energy-saving effect.

[0065] SS6. Mode switching and fault tolerance adjustment:

[0066] Under the conditions of sudden changes in external operating conditions or changes in user requirements, the operation mode switching process is triggered. First, the heat storage or cold storage energy of the system is preferentially retained, and then the path configuration, valve switching, and cycle regulation under the new mode are executed to ensure the stable, energy-saving operation of the system and its robustness.

[0067] In the heat storage mode, as Figure 4 shown, the control and switching unit 50 first coordinates and controls the opening states of the relevant control valves to empty the cold fluid channel 15, and all liquid cold fluid media are stored in the cold storage container 30 or discharged. Then, the second outlet of the third three-way control valve 52 leading to the cold storage container 30 is closed, and the first outlet leading to the hot fluid channel is opened. At the same time, the fourth three-way control valve 54 is completely closed to ensure that the cold fluid loop does not participate in the current operation. After that, the first three-way control valve 51 opens its inlet and first outlet and closes the second outlet to connect the outlet of the hot fluid channel 14 with the inlet of the heat storage container 20. The second three-way control valve 52 opens its second inlet and outlet and closes the first inlet to connect the outlet of the heat storage container 20 with the first inlet of the four-way control valve 56. And the four-way control valve 56 connects the first inlet and the first outlet at this time, and closes the second inlet and the second outlet. At the same time, the fifth three-way control valve 55 related to the air heat exchange side of the heat exchange regulating device 40 is completely closed, and only the flow path between the hot fluid channel 14 and the heat storage container 20 is retained to avoid unnecessary air heat exchange. In this heat storage state, the nanofluid medium flows in the hot fluid channel 14 driven by the circulation pump 57, absorbs the solar radiation energy passing through the top transparent cover plate 11, and enters the heat storage container 20 after heating for high-temperature sensible heat storage.

[0068] When it is necessary to switch from the heat storage mode to the heating mode, for the indoor heating demand under night or low irradiation conditions, the connection states of the first and second three-way control valves 51 and 52 and the four-way control valve 56 are maintained unchanged. The fifth three-way control valve 55 on the air heat exchange side of the heat exchange regulating device 40 is opened, and the air delivery fan 59 is started to exchange heat between the high-temperature nanofluid and the external supply air in the heat exchange regulating device 40 to achieve indoor heating, as Figure 5 shown; for the heating demand under high irradiation conditions during the day, a direct heating mode of collecting and heating simultaneously or a parallel mode of heating and heat storage is adopted. The first three-way control valve 51 is switched to connect the inlet and the second outlet and the first outlet is closed or partially opened, and the second three-way control valve 52 is switched to connect the first inlet and the outlet and the second inlet is closed or partially opened to achieve immediate use of the heat energy or dynamically divert part of the hot fluid into the heat storage container 20, as Figure 6 shown.

[0069] In the cold storage mode, as Figure 7As shown, the control and switching unit first coordinates and controls the opening states of the relevant control valves to empty the hot fluid channel, and stores all the nanofluid media in the heat storage container 20. Then, it closes all the control valves and the circulation pump 57 that are connected to the hot fluid channel 14 and the heat storage container 20. After that, it opens the inlet and the first outlet of the third three-way control valve 53 and closes the first outlet leading to the hot fluid channel 14, opens the first inlet and the outlet of the fourth three-way control valve 54 and closes the second inlet, and the four-way control valve 56 connects the second inlet and the first outlet while closing the other flow paths, ensuring that only the liquid cold fluid media in the cold storage container 30 enter the cold fluid channel 15 and ensuring that a circulation path is formed between the cold storage container 30 and the cold fluid channel 15. At the same time, the fifth three-way control valve 55 remains fully closed to avoid air heat exchange interfering with the cold storage process. In the cold storage state, the liquid cold fluid media flow in the cold fluid channel 15 driven by the circulation pump 58, radiate heat outward into outer space with a high emissivity within the wavelength range of 8 - 13 μm through the radiation cooler 12, and after the cold fluid media are cooled, they enter the cold storage container 30 for sensible heat storage, which is applicable to high-temperature daytime periods or nighttime cold source reserves.

[0070] When it is necessary to switch from the cold storage mode to the cooling mode, if the radiation cooling working conditions are good (such as high atmospheric window transparency and low external air temperature), the direct radiation cooling ventilation cooling mode is adopted. At this time, the third three-way control valve and the liquid cold fluid circulation pump 58 are closed, the second inlet and the outlet of the fourth three-way control valve 54 are switched to be connected and the first inlet is closed, the four-way control valve 56 is switched to connect the second inlet and the second outlet while closing the other flow paths. At the same time, the first inlet and the outlet of the fifth three-way control valve 55 are opened and the second inlet is closed, and the air delivery fan 59 is started, so that the air in the air environment directly contacts the radiation cooler 12 through the cold fluid channel 15 to achieve passive cooling, and the cooled air is sent into the indoor space through the fifth three-way control valve 55 to achieve cooling, and the liquid cold fluid media in the cold storage container 30 do not participate in the cooling, as Figure 8 shown.

[0071] When the radiation cooling working conditions are poor (such as cloud cover and too high external temperature), it is switched to the active cold source cooling mode. At this time, the second inlet of the fourth three-way control valve 54 is closed and the first inlet and the outlet are opened, and the four-way control valve 56 is switched to connect the second inlet and the first outlet while closing the other flow paths, so that the low-temperature liquid cold fluid media in the cold storage container 30 enter the media heat exchange side of the heat exchange and regulation device 40 through the cold fluid channel 15 and the four-way control valve 56. At the same time, the second inlet and the outlet of the fifth three-way control valve 55 are opened and the first inlet is closed, and the air delivery fan 59 is started to introduce air into the air heat exchange side of the heat exchange and regulation device 40, and perform forced heat exchange with the low-temperature cold fluid to cool the air and then send it into the indoor space to form cold storage-assisted cooling, as Figure 9 shown.

[0072] Through the detailed description of the above steps, this embodiment completely elaborates the control method of the solar heating and radiative cooling building energy-saving system integrating cool storage and heat storage, realizing the intelligent switching of the system operation mode and the efficient utilization of energy. This control method can flexibly adjust the operation state of the system according to environmental parameters and user requirements, ensuring that the system can maintain efficient and stable operation under different seasons and day-night conditions, thereby achieving the goal of building energy conservation.

[0073] Through the above embodiments, the object of the present invention is completely and effectively achieved. Those skilled in the art can understand that the present invention includes but is not limited to the content described in the drawings and the above specific embodiments. Although the present invention has been described with reference to the currently considered most practical and preferred embodiments, it should be understood that the present invention is not limited to the disclosed embodiments, and any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. An energy-saving system for solar heating and radiative cooling of buildings integrated with cold and heat storage, characterized in that, The system at least includes a thermal-cold coupling conversion module, a heat storage container, a cold storage container, a heat exchange regulating device, and a control and switching unit, where: The thermal-cold coupling conversion module includes a transparent cover plate, a radiative cooler, and a support plate that are arranged at intervals from top to bottom in sequence, where: the transparent cover plate is arranged on the outermost layer of the module, and a hot fluid channel is formed between the transparent cover plate and the radiative cooler for flowing a nanofluid medium with strong light absorption ability; the radiative cooler includes multiple layers of thin films arranged in a stack, and is integrally configured to have a high reflectivity in the solar spectrum range and a high emissivity in the 8-13 μm atmospheric window wavelength range; a cold fluid channel is formed between the radiative cooler and the support plate for flowing a cold fluid medium; The control and switching unit is used to realize the switching and regulation of four operating modes of heat storage, heat supply, cold storage, and cold supply according to external environmental parameters and indoor heat load requirements, where: in the heat storage mode, the cold fluid channel is emptied, and the nanofluid medium absorbs solar radiation energy in the hot fluid channel and stores the heat energy in the heat storage container; in the heat supply mode, the high-temperature nanofluid medium in the heat storage container heats air through the heat exchange regulating device to realize indoor heating; in the cold storage mode, the hot fluid channel is emptied, and the liquid cold fluid medium radiatively dissipates heat through the radiative cooler in the cold fluid channel and stores the cold energy in the cold storage container; in the cold supply mode, the cooling air directly passes through the cold fluid channel, or the low-temperature liquid cold fluid medium in the cold storage container cools air through the heat exchange regulating device to realize indoor cold supply.

2. The integrated solar energy heating and radiative cooling building energy-saving system with cold and heat storage according to claim 1, wherein The nanofluid medium is a two-component nanofluid in which silver nanoparticles and graphene are compounded and dispersed in deionized water. By controlling the nanoparticle concentration at about 100 ppm, its average transmittance in the 0.25-2.5 μm solar spectrum range is not higher than 5%, and its absorptance of solar radiation reaches more than 99% when the depth is 1 cm; The radiative cooler adopts a six-layer thin film structure, which is successively MgF2, TiO2, MgF2, SiN, SiO2, and MgF2 layers from top to bottom. The thickness range of each layer of film is 0.3-3.0 μm, and spectral design is carried out by the characteristic matrix method to make the peak emissivity and the atmospheric transmittance overlap and match in the 8-13 μm atmospheric window band and the radiative emissivity is not less than 94%, and the reflectivity in the 0.25-2.5 μm solar spectrum range is not less than 90%, so as to realize the radiative cooling ability that can operate day and night.

3. The integrated solar heating and radiative cooling building energy-saving system with cold and heat storage according to claim 1 or 2, characterized in that The control and switching unit includes several control valves. A first three-way control valve is provided at the inlet end of the heat storage container, and a second three-way control valve is provided at the outlet end; a four-way control valve is provided at the inlet end of the medium heat exchange side of the heat exchange regulating device, and a third three-way control valve is provided at the outlet end; a fourth three-way control valve is provided at the outlet end of the cold storage container; a fifth three-way control valve is provided on the outlet pipeline of the air heat exchange side of the heat exchange regulating device; and The inlet of the first three-way control valve is connected to the outlet of the hot fluid channel, the first outlet is connected to the inlet of the heat storage container, and the second outlet is connected to the first inlet of the second three-way control valve; the second inlet of the second three-way control valve is connected to the outlet of the heat storage container, and the outlet is connected to the first inlet of the four-way control valve; the second inlet of the four-way control valve is connected to the outlet of the cold fluid channel, the first outlet is connected to the inlet of the medium heat exchange side of the heat exchange regulation device, and the second outlet is connected to the first inlet of the fifth three-way control valve; the inlet of the third three-way control valve is connected to the outlet of the medium heat exchange side of the heat exchange regulation device, the first outlet is connected to the inlet of the hot fluid channel, and the second outlet is connected to the inlet of the cold storage container; the first inlet of the fourth three-way control valve is connected to the outlet of the cold storage container, the second inlet is connected to the air environment, and the outlet is connected to the inlet of the cold fluid channel; the second inlet of the fifth three-way control valve is connected to the outlet of the air heat exchange side of the heat exchange regulation device, and the outlet is connected to the air environment; and the inlet of the air heat exchange side of the heat exchange regulation device is connected to the air environment.

4. The solar heating and radiative cooling building energy-saving system integrating cold and heat storage according to claim 3, characterized in that, A nanofluid circulation pump is provided on the outlet pipeline of the hot fluid channel, which is used to drive the nanofluid medium to circulate between the hot fluid channel, the heat storage container and the medium heat exchange side of the heat exchange regulation device; a liquid cold fluid circulation pump is provided on the inlet pipeline of the cold storage container, which is used to drive the liquid cold fluid medium to circulate between the cold fluid channel, the cold storage container and the medium heat exchange side of the heat exchange regulation device; an air delivery fan is provided on the outlet pipeline of the fifth three-way control valve, which is used to drive air to pass through the air heat exchange side of the heat exchange regulation device or directly through the cold fluid channel.

5. The integrated solar energy heating and radiant cooling building energy-saving system with cold and heat storage according to claim 4, wherein The control and switching unit at least includes an environment monitoring module and an execution control module. The environment monitoring module at least includes a plurality of sensors for monitoring and collecting solar radiation intensity, outdoor temperature, indoor temperature, heat storage temperature, cold storage temperature, supply air temperature, and the opening states of each control valve. Each sensor, control valve, circulation pump, and air delivery fan are all communicatively connected to the execution control module. The execution control module judges the current operating state based on the data collected by the environment monitoring module and the target temperature or operating mode set by the user, and issues an adjustment instruction through the built-in control logic to jointly control each control valve, each circulation pump, and the fan in the system.

6. A control method for an integrated solar heating and radiative cooling building energy-saving system with cold and heat storage as claimed in claim 5, characterized in that, At least includes the following steps: SS1. Real-time collect the solar radiation intensity, outdoor ambient temperature, indoor air temperature, heat storage container temperature, cold storage container temperature, and the target temperature set by the user. Based on the preset control logic, analyze the current environmental conditions and the building heat load demand, and determine the operating mode that the system should adopt currently. SS2. According to the determined operating mode, by coordinating the states of each three-way control valve, four-way control valve, circulation pump, and fan, empty the working fluid circuits that do not participate in the operation currently, recover the hot fluid or cold fluid to the heat storage container or cold storage container respectively, and isolate the subsystem paths of non-current modes. SS3. According to the determined operating mode, control the opening states of each three-way control valve and four-way control valve to reconfigure the fluid path. In the heat storage mode, empty the cold fluid channel and establish a circulation path between the hot fluid channel and the heat storage container. In the heat supply mode, connect the heat exchange loop between the heat storage container and the heat exchange regulating device. In the cold storage mode, empty the hot fluid channel and establish a circulation path between the cold fluid channel and the cold storage container. In the cold supply mode, select the direct cooling or energy storage cooling path according to the radiative cooling conditions; SS4. According to the current operating mode, start and adjust the operating frequencies of the selected circulation pumps and air delivery fans, and control and adjust the mass flow rates of each fluid. In the heat storage and heat supply modes, optimize the circulation rate of the nanofluid medium to optimize the solar absorption efficiency and heat exchange efficiency. In the cold storage and cold supply modes, adjust the cold fluid circulation rate and air flow rate to optimize the radiative cooling effect and indoor temperature control; SS5. Continuously monitor the temperature changes and energy efficiency indicators during the system operation. When it is detected that the indoor temperature deviates from the set target temperature, precisely control the supply air temperature by adjusting the fluid mass flow rate, heat capacity flow ratio Rc, and number of transfer units Ntu parameters; SS6. Under the conditions of sudden changes in external working conditions or changes in user requirements, trigger the operating mode switching process, give priority to retaining the heat storage or cold storage energy of the system, and then perform path configuration, valve switching, and circulation adjustment in the new mode to ensure the stable, energy-saving operation of the system and its robustness.

7. The integrated solar heating and radiant cooling building energy-saving system with cold and heat storage according to claim 6, characterized in that, In the heat storage mode, the control and switching unit first coordinately controls the opening states of each relevant control valve to empty the cold fluid channel, and all liquid cold fluid media are stored in the cold storage container or discharged. Then, close the second outlet of the third three-way control valve leading to the cold storage container and open the first outlet leading to the hot fluid channel, and at the same time completely close the fourth three-way control valve; After that, the first three-way control valve opens its inlet and first outlet and closes the second outlet to connect the outlet of the hot fluid channel with the inlet of the heat storage container. The second three-way control valve opens its second inlet and outlet and closes the first inlet to connect the outlet of the heat storage container with the first inlet of the four-way control valve. And at this time, the four-way control valve connects the first inlet with the first outlet, closes the second inlet and second outlet, and at the same time completely closes the fifth three-way control valve related to the air heat exchange side of the heat exchange regulating device; In the heat storage state, the nanofluid medium flows in the hot fluid channel driven by the circulation pump, absorbs the solar radiation energy passing through the top transparent cover plate, and after heating, enters the heat storage container for sensible heat storage.

8. The integrated solar heating and radiative cooling building energy-saving system with cold and heat storage according to claim 7, characterized in that, When it is necessary to switch from the heat storage mode to the heat supply mode, for the indoor heat supply demand under night or low irradiation conditions, maintain the connected states of the first and second three-way control valves and the four-way control valve unchanged, open the fifth three-way control valve on the air heat exchange side of the heat exchange regulating device, and start the air delivery fan to exchange heat between the high-temperature nanofluid and the external supply air to achieve indoor heating; For the heating demand under high irradiation conditions, a direct heating mode of collecting and heating simultaneously or a parallel mode of heating and heat storage is adopted. The first three-way control valve is switched to connect the inlet with the second outlet while the first outlet is closed or partially opened, and the second three-way control valve is switched to connect the first inlet with the outlet while the second inlet is closed or partially opened, so as to realize the immediate use of the heat energy or dynamically divert part of the hot fluid into the heat storage container.

9. The integrated solar heating and radiative cooling building energy-saving system with cold and heat storage according to claim 6, characterized in that, In the cold storage mode, the control and switching unit first coordinates and controls the opening states of the relevant control valves to empty the hot fluid channel, and all the nanofluid media are stored in the heat storage container. Then, all the control valves and the circulation pump connected to the hot fluid channel and the heat storage container are closed. After that, the inlet and the first outlet of the third three-way control valve are opened and the first outlet leading to the hot fluid channel is closed. The first inlet and the outlet of the fourth three-way control valve are opened and the second inlet is closed. The four-way control valve connects the second inlet with the first outlet and the remaining flow paths are closed. At the same time, the fifth three-way control valve remains fully closed to avoid the interference of air heat exchange on the cold storage process. In the cold storage state, the liquid cold fluid medium flows in the cold fluid channel driven by the circulation pump, radiates heat to outer space with a high emissivity in the wavelength range of 8 - 13 μm atmospheric window through the radiation cooler, and the cold fluid medium enters the heat storage container for sensible heat storage after cooling.

10. The integrated solar energy heating and radiative cooling building energy-saving system with cold and heat storage according to claim 9, characterized in that, When it is necessary to switch from the cold storage mode to the cooling mode, if the radiation cooling working conditions are good, a direct radiation cooling ventilation cooling mode is adopted. At this time, the third three-way control valve and the liquid cold fluid circulation pump are closed. The second inlet and the outlet of the fourth three-way control valve are switched to be connected and the first inlet is closed. The four-way control valve is switched to connect the second inlet with the second outlet and the remaining flow paths are closed. At the same time, the first inlet and the outlet of the fifth three-way control valve are opened and the second inlet is closed, and the air delivery fan is started, so that the air in the air environment directly contacts the radiation cooler through the cold fluid channel to realize passive cooling, and the cooled air is sent into the indoor space through the fifth three-way control valve to realize cooling. When the radiation cooling working conditions are poor, it is switched to the active cold source cooling mode. At this time, the second inlet of the fourth three-way control valve is closed and the first inlet and the outlet are opened. The four-way control valve is switched to connect the second inlet with the first outlet and the remaining flow paths are closed, so that the low-temperature liquid cold fluid medium in the heat storage container enters the medium heat exchange side of the heat exchange and regulation device through the cold fluid channel and the four-way control valve. At the same time, the second inlet and the outlet of the fifth three-way control valve are opened and the first inlet is closed, and the air delivery fan is started to introduce air into the air heat exchange side of the heat exchange and regulation device, and perform forced heat exchange with the low-temperature cold fluid to cool the air and then send it into the indoor space to form cold storage assisted cooling.

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