Photovoltaic photo-thermal energy storage multi-element coupled all-weather self-adaptive building energy system and method

Abstract

The invention discloses a photovoltaic photo-thermal energy storage multi-element coupled all-weather self-adaptive building energy system and method, and belongs to the crossing field of solar comprehensive utilization and building energy saving. The system integrates a Fresnel lens, a frequency division film, a photovoltaic power generation unit, a thermoelectric power generation unit and a multi-temperature-zone phase change energy storage device, and the surface of the photovoltaic and thermoelectric unit is covered with an aerogel heat collection and insulation layer. Sunlight is focused by a Fresnel lens and then is separated into short-wave light and long-wave light by a frequency division film, and power generation waste heat is stored in a cascade mode through a phase change energy storage device; the intelligent control unit switches a heat supply season mode or a cold supply season mode according to seasons and energy consumption requirements. The system improves the solar spectrum utilization rate, achieves all-weather self-adaptive supply of electricity and heat of the building, is compact in structure, low-carbon and efficient, and is suitable for various building energy scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of comprehensive utilization of solar energy and building energy saving, and particularly relates to a photovoltaic-photothermal energy storage multi-element coupling all-weather self-adaptive building energy system and method. BACKGROUND

[0002] With the continuous advancement of the double carbon target and the growing demand for green buildings, solar energy, as a renewable and clean energy, its efficient integration and multi-dimensional utilization in building energy systems are becoming the focus of research and engineering practice. Currently, the main utilization methods of solar energy include photovoltaic power generation and photothermal conversion. Photovoltaic technology directly converts light energy into electrical energy through semiconductor materials, which has the advantages of clean conversion process and easy distributed deployment. However, its main response band is concentrated in the visible light range, and the utilization ability of infrared and other medium and long wave energy is weak, and the efficiency will decrease with the increase of component working temperature. Photothermal technology absorbs radiant heat through a heat collector and uses it for domestic hot water, space heating or heat and power generation. The response band is wider, but most systems are large in size, slow in response and low in flexibility, making it difficult to meet the diversity and intelligent requirements of modern buildings for energy supply methods.

[0003] To overcome the limitations of single technology, some research has begun to explore multi-energy complementary systems that combine photovoltaic and photothermal technologies. However, most current joint utilization schemes still have the following key problems: first, the spectral utilization efficiency is low, and there is a lack of mechanism for dividing the waveband functions of sunlight, resulting in competition for absorption and mutual interference between photovoltaic and photothermal components, and low overall conversion efficiency; second, the energy regulation and storage capacity is insufficient, and traditional thermal energy storage methods are difficult to achieve dynamic matching with building cooling and heating loads, lacking efficient thermal energy gradient management and release mechanisms; third, the system integration is not high, and photovoltaic, photothermal and energy storage components are often deployed in a stacked and spliced manner, resulting in loose structure, large space occupation and complex maintenance; fourth, the operation mode lacks intelligent control, making it difficult to automatically switch and optimize energy efficiency according to environmental conditions and user loads, especially in regions with significant seasonal changes, where system operation efficiency decreases significantly.

[0004] In addition, current photothermal power generation technology is mostly based on large-scale turbine power generation mode, which requires a high temperature difference and a large system, and is not suitable for small and medium-sized building energy scenarios. In contrast, thermoelectric material-based thermoelectric power generation technology can achieve thermoelectric conversion at a lower temperature gradient, with the advantages of compact structure, high modularity, easy integration with buildings, and other advantages, making it a potential technology path to improve the thermal energy utilization efficiency of building energy systems.

[0005] In summary, the existing solar energy utilization system is still difficult to meet the comprehensive demand of multi-energy cooperation, efficient conversion, flexible energy storage, intelligent control and compact integration in building scenarios. Therefore, it is urgent to design a building energy system integrating spectral separation, photovoltaic power generation, thermoelectric power generation, multi-temperature zone phase change heat storage, intelligent fluid control and seasonal self-adaptive operation mode, to realize the full-spectrum, high-efficiency and multi-purpose comprehensive utilization of solar energy in buildings, and help to realize the low-carbonization and intelligent upgrading of distributed energy systems. SUMMARY

[0006] The present application aims to solve the problems of low spectral utilization rate, single energy output, insufficient heat storage regulation and low seasonal operation efficiency in the existing solar energy utilization system, and proposes a photovoltaic-thermal energy storage multi-element coupling all-weather self-adaptive building energy system and method. Through multiple integrated innovations such as optical frequency division, thermoelectric cooperative conversion, cascade heat storage and intelligent control, the system realizes efficient, flexible and all-year applicable comprehensive utilization of solar energy in building energy scenarios.

[0007] To solve the above technical problems, the present application realizes the following technical scheme: In a first aspect, the present application provides a photovoltaic-thermal energy storage multi-element coupling all-weather self-adaptive building energy system, comprising: a Fresnel lens for focusing sunlight; a frequency division film arranged on the light path of the Fresnel lens for separating sunlight into short-wave light and long-wave light according to wavelength; a photovoltaic power generation unit for receiving the short-wave light and performing photoelectric conversion; a thermoelectric power generation unit for receiving the long-wave light and heating the working medium, and utilizing temperature difference to generate electricity; an energy storage system connected to the photovoltaic power generation unit and the thermoelectric power generation unit respectively, for storing heat energy generated during power generation and releasing heat according to demand.

[0008] As a preferred technical scheme of the present application, the light-receiving surface of the photovoltaic power generation unit and the hot end of the thermoelectric power generation unit are sequentially covered with an anti-reflection coating and an aerogel heat collection and insulation layer from the inside to the outside.

[0009] As a preferred technical scheme of the present application, the anti-reflection coating is composed of one or more materials selected from SiO2, MgF2 or TiO2, with a thickness of 100-120 nm and a reflectivity not higher than 5%.

[0010] As a preferred technical scheme of the present application, the aerogel heat collection and insulation layer is high-transmittance silica aerogel with a thickness of 5-20 mm, a visible light transmittance not lower than 80% and a thermal conductivity not higher than 0.02 W / m·K.

[0011] As a preferred technical solution of the present application, the energy storage system comprises a heat storage circuit, the heat storage circuit comprising a first heat exchanger, a second heat exchanger, a phase change energy storage device, a circulating pipeline and a circulating pump, the first heat exchanger being arranged on the back of the photovoltaic power generation unit, the second heat exchanger being arranged on the cold end of the thermoelectric power generation unit, the second heat exchanger outlet being connected with the phase change energy storage device inlet, the first heat exchanger inlet being connected with the phase change energy storage device outlet, and the two heat exchangers being connected in series.

[0012] As a preferred technical solution of the present application, the energy storage system further comprises a heat dissipation circuit, the heat dissipation circuit comprising a three-way valve and a radiator, the three-way valve being installed on the circulating pipeline of the heat storage circuit, the first port of the three-way valve being connected with the second heat exchanger outlet, the second port being connected with the phase change energy storage device inlet, and the third port being connected with the radiator inlet, and the radiator outlet being connected with the first heat exchanger inlet.

[0013] As a preferred technical solution of the present application, the circulating pipelines of the heat storage circuit and the heat dissipation circuit are both provided with throttling valves.

[0014] As a preferred technical solution of the present application, the phase change energy storage device comprises a high-temperature phase change material layer, a medium-temperature phase change material layer and a low-temperature phase change material layer arranged in sequence, and an internal spiral pipe penetrating through the layers; a heat insulation layer is arranged between the layers, and a heat exchange pipeline connecting different heat supply ends is arranged in each layer.

[0015] As a preferred technical solution of the present application, the phase change temperature of the high-temperature phase change material layer is 40-60℃, and the phase change latent heat is not less than 250J / g; the phase change temperature of the medium-temperature phase change material layer is 20-40℃, and the phase change latent heat is not less than 200J / g; the phase change temperature of the low-temperature phase change material layer is 5-20℃, and the phase change latent heat is not less than 150J / g; the heat insulation layer is one or more laminates of aerogel composite felt, glass wool or polyurethane foam, and the thickness is 30-50mm, and the thermal conductivity coefficient is not higher than 0.03 W / m·K.

[0016] In the second aspect, the present application provides an operation method of the all-weather self-adaptive building energy system for the photovoltaic-thermal energy storage multi-element coupling, which is characterized by comprising the following steps: In the heating season, sunlight is focused by the Fresnel lens, and after the frequency separation film separates the wave bands, the short waves are introduced into the photovoltaic power generation unit to generate electricity, the long waves are introduced into the thermoelectric power generation unit to generate electricity, and the hot working medium is guided to flow into the phase change energy storage device through the three-way valve to heat the heat supply end or supply hot water; In the cooling season, when the building has no heat demand, the hot working medium is guided to flow into the radiator through the three-way valve to reduce the cold end temperature of the power generation unit. In the transition season, the system intelligently allocates heat to the heat storage circuit or the heat dissipation circuit according to the real-time energy consumption demand, balances the heat storage and heat dissipation demand.

[0017] Compared with the prior art, the present application has the following beneficial effects: The application discloses a photovoltaic-thermoelectric energy storage multi-element coupling all-weather self-adaptive building energy system, and aims to solve the problems of low spectral utilization, single energy output, insufficient heat storage regulation and low seasonal operation efficiency in existing solar energy utilization systems.

[0018] The system takes a Fresnel lens and a frequency division film as optical cores. The Fresnel lens is responsible for high-density focusing of incident sunlight, improving the light energy flux density. The application introduces a silicon dioxide / fluorosilane composite protective coating on the surface of the Fresnel lens. The coating can significantly improve the wear resistance and anti-pollution ability of the lens surface, maintain high light transmittance, and have hydrophobic and oleophobic properties, so that the mirror surface remains clean under long-term outdoor operating conditions, reducing maintenance costs. The frequency division film adopts a multi-layer dielectric interference structure design. By alternately depositing high refractive index materials (such as TiO2) and low refractive index materials (such as SiO2) on a quartz substrate, the film can accurately regulate the sunlight spectrum: the transmittance of the short-wave band (300-800 nm) is greater than 90%, and the reflectivity of the long-wave band (800-2500 nm) is greater than 85%. The structure has the characteristics of high transmittance, low absorption, strong ultraviolet resistance and weather resistance, and is suitable for long-term operation of outdoor building energy systems. Based on the interference and reflection principles, the focused light is separated by wavelength: short-wave band light (about 300-800 nm) is transmitted to the photovoltaic power generation unit for photoelectric conversion; medium and long-wave band light (about 800-2500 nm) is reflected to the thermoelectric power generation unit for heating the hot end and realizing thermoelectric power generation. This spectrum allocation mechanism avoids the competition for light energy between traditional photovoltaic and photothermal systems, significantly improving the comprehensive energy conversion efficiency.

[0019] In the energy conversion part, the photovoltaic unit uses high-efficiency crystalline silicon or multi-junction solar cells to directly convert short-wave light into direct current to power building lighting, household appliances or energy storage systems; the thermoelectric power generation unit uses the temperature difference between the hot end and the cold end heated by the infrared wave band to generate electricity to supplement the power output. The present application sets an anti-reflection coating on the surface of the photovoltaic unit and covers an aerogel heat collecting and insulating layer on the outer layer. The anti-reflection coating can reduce the reflectivity to below 5% to improve the light incidence rate; the aerogel heat collecting and insulating layer reduces infrared loss through the mechanism of "high light transmission + low thermal conductivity", and the synergistic effect of the two significantly improves the power generation efficiency of the photovoltaic module and the overall energy utilization rate of the system. The introduction of the aerogel heat collecting and insulating layer forms a transparent thermal barrier on the surface of the photovoltaic and thermoelectric units, which can not only ensure the effective penetration of solar radiation but also block the loss of infrared heat, forming a local greenhouse effect, thereby improving the stability of the photovoltaic cell and the temperature difference efficiency of the thermoelectric unit. At the same time, the aerogel heat collecting and insulating layer also has the functions of wind and sand resistance, anti-fouling and weather protection, prolonging the service life of the module. The waste heat generated in the thermoelectric power generation process is transferred to the multi-temperature zone phase change heat storage device through a high-thermal-conductivity heat exchanger, and is stored in high-temperature (40-60℃), medium-temperature (20-40℃) and low-temperature (5-20℃) zones in gradient, realizing on-demand energy supply for different needs such as domestic hot water, building heating and low-temperature heating.

[0020] In terms of energy management, according to the environmental temperature, light intensity, heat storage state and energy demand, the system automatically switches the operation mode through a three-way valve. The system is configured with a circulating pump to provide the power source for the working medium circulation, and can realize variable speed regulation in combination with an intelligent control module to adapt to the flow demand in different operation modes. In the heating season mode, the heat is preferentially output to the heating terminal, and the photovoltaic and thermoelectric power generation are simultaneously performed; in the cooling season mode, the heat is discharged to the environment through the radiator to reduce the cold end temperature and improve the power generation efficiency; in the transition season mode, the electric energy and the thermal energy are flexibly distributed to balance the heat storage and heat dissipation demand.

[0021] To solve the intermittency and instability of solar energy, the present application introduces multi-temperature zone phase change heat storage material, which uses its high latent heat characteristics to store excess heat when the sunlight is sufficient, and releases it on demand at night or on cloudy days, realizing peak clipping and valley filling. The heat storage device adopts a heat preservation and insulation structure and a spiral heat exchanger pipe to ensure efficient heat transfer and long-time heat preservation. The present application sets an insulation and heat preservation layer on the outer wall of the heat storage unit and the outer layer of the circulating pipeline, and optimally adopts a composite structure of aerogel composite felt and glass wool superimposed, with a thickness range of 20-50mm and a thermal conductivity ≤0.03W / m·K. This structure not only has excellent insulation performance but also has the characteristics of high temperature resistance, aging resistance and high mechanical strength, suitable for long-term outdoor use. The present application uses a water-glycol mixed solution as the circulating working medium, and the volume fraction ratio of water to glycol is preferably 70:30-50:50. This ratio can effectively prevent the working medium from freezing under low temperature conditions, and can also maintain a high thermal conductivity and a low viscosity to ensure stable operation of the system under different climate conditions.

[0022] In addition, the present application introduces aerogel thermal insulation layer and throttle valve, further improving the stability and energy efficiency of the system operation. The aerogel heat collecting and insulating layer described in the present application preferably uses a silica aerogel composite board with a thickness of 5-20 mm, which can not only ensure high light transmittance to enhance the light energy acquisition of photovoltaic and thermoelectric units, but also form good thermal insulation effect to reduce infrared loss. According to different climate conditions, the thickness can be selected within the range of 5-10 mm (light transmittance priority) and 10-20 mm (thermal insulation priority). The throttle valve is used for dynamic regulation of working fluid flow and pressure, and the three-way valve is combined to form a double-valve intelligent control mechanism, so that the system can realize smooth transition during mode switching, avoiding energy impact and efficiency loss.

[0023] In terms of structural design, the system uses modular and high-integration arrangement, closely combining light collection, frequency division, photovoltaic, thermoelectric, heat exchange, heat storage and control modules, which is suitable for installation on building roofs, balconies or ground platforms, and can be equipped with solar tracking devices to maximize the annual sunshine utilization rate. The system can expand multiple photovoltaic and thermoelectric units according to the application scale, which can be integrated into the power grid for operation, or used as an off-grid independent energy system in remote areas, communication base stations and other scenarios.

[0024] In summary, the present application utilizes the full-spectrum characteristics of solar energy, realizes the collaborative work of photovoltaic power generation, thermoelectric power generation and multi-temperature zone heat storage through precise spectral separation and multiple energy conversion paths, and realizes adaptive switching of operation mode through intelligent control, with the advantages of high energy efficiency, strong flexibility, wide application range, etc., which can provide clean, safe and efficient comprehensive solutions for building energy systems. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Figure 1 is a schematic diagram of the overall structure of the present application.

[0026] Figure 1 is a schematic diagram of the overall structure of the present application. DETAILED DESCRIPTION

[0027] In order for those skilled in the art to better understand the technical solutions of the present application, the preferred embodiments of the present application are described below in combination with specific examples, but it should be understood that the drawings are only used for illustrative description and cannot be understood as a limitation on the patent; in order to better illustrate the examples, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationship described in the drawings is only used for illustrative description and cannot be understood as a limitation on the patent.

[0028] The photovoltaic-photothermal energy storage multi-element coupled all-weather adaptive building energy system of the present application is mainly applicable to the energy supply scene of high-rise civil buildings, commercial office buildings, schools and hospital public buildings, and is particularly suitable for regions with significant seasonal temperature difference (such as winter minimum temperature ≤-10℃, summer maximum temperature ≥30℃) and annual sunshine hours ≥2000h (such as North China, East China and part of Northwest China), which can realize the integrated protection of building electricity, domestic hot water supply and winter heating, and at the same time support off-grid mode (such as remote communication base station) or grid-connected mode operation, with the characteristics of high integration, low operation and maintenance cost and strong environmental adaptability.

[0029] As shown in Figure 1 The present application provides a photovoltaic-photothermal energy storage multi-element coupled all-weather adaptive building energy system, which comprises a Fresnel lens, a frequency separation film, a photovoltaic power generation unit, a thermoelectric power generation unit, an energy storage system, an anti-reflection coating and an aerogel heat collection and heat preservation layer.

[0030] In some embodiments, the Fresnel lens 1 is used to focus sunlight; the frequency separation film 2 is arranged on the light path of the Fresnel lens and is used to spectrally separate the focused light by wavelength.

[0031] Specifically, the Fresnel lens 1 is injection molded with polymethyl methacrylate (PMMA) material, with a diameter of 1200-1500mm and a focal length of 800-1000mm; its surface is coated with a fluorosilane composite anti-fouling and wear-resistant coating based on silica nanoparticles, with a coating thickness of 5-10µm; the silica nanoparticles are embedded in the silicone matrix through inorganic-organic composite process and modified by fluorosilane; the actual transmittance is ≥90%, the pencil hardness is ≥3H, and the water contact angle is ≥100°, which can realize dust prevention, self-cleaning and ultraviolet aging resistance (weather resistance test meets 5000h ultraviolet irradiation without cracking, transmittance attenuation ≤5%) in outdoor environment, ensuring long-term stable light collection of the lens in outdoor environment, and being able to have high transmittance, anti-fouling and wear resistance.

[0032] Specifically, the frequency division film 2 adopts quartz glass as the substrate, and a 20-layer multi-layer dielectric film structure is formed by alternately depositing high refractive index layers and low refractive index layers through an electron beam evaporation process; the high refractive index layer is selected from titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), or niobium pentoxide (Nb2O5), and is preferably titanium dioxide (TiO2), with a thickness of 80-120 nm; the low refractive index layer is selected from silicon dioxide (SiO2), magnesium fluoride (MgF2), or aluminum oxide (Al2O3), and is preferably silicon dioxide (SiO2), with a thickness of 100-150 nm; by precisely controlling the thickness and number of layers, the spectral separation characteristics are achieved: the transmittance of short-wave light of 300-800 nm is ≥90%, and the reflectivity of long-wave light of 800-2500 nm is ≥85%; the film layer parameters can be fine-tuned according to the actual application scenario (such as the need to improve long-wave utilization in high-latitude areas) to optimize the spectral matching degree of photovoltaic and thermoelectric units.

[0033] In some embodiments, the photovoltaic power generation unit 4 is used to receive short-wave light transmitted by the frequency division film and generate electricity through photovoltaic effect; the thermoelectric power generation unit 3 is used to receive long-wave light reflected by the frequency division film and heat the working medium, respectively realizing short-wave light photoelectric conversion and long-wave light temperature difference power generation.

[0034] Specifically, the photovoltaic power generation unit 4 adopts crystalline silicon cells, multi-junction solar cells, or perovskite components (conversion efficiency ≥23%), and forms a 2x3 array (total power about 300W) with high conversion efficiency and good weak light response capability; the output power can be used for building electricity load or grid-connected power supply.

[0035] Further, the surface of the photovoltaic power generation unit 4 is sequentially covered by an anti-reflection coating 5 and an aerogel heat collecting and insulating layer 6 from the inside to the outside: the anti-reflection coating 5 is composed of one or more materials selected from SiO2, MgF2, or TiO2, and preferably uses a single layer of SiO2 material prepared by sol-gel method, with a thickness of 100-120 nm and a measured reflectivity of ≤5%. The aerogel heat collecting and insulating layer 6 is a silica-based transparent composite material, with a thickness of 10-20 mm (20 mm is recommended in North China to enhance insulation, and 10 mm can be selected in South China to balance light transmission and insulation), a light transmittance of ≥85%, and a thermal conductivity of ≤0.018 W / m·K; the aerogel heat collecting and insulating layer 6 has high light transmittance and low thermal conductivity, which can not only transmit short-wave sunlight to enhance the energy acquisition of photovoltaic and thermoelectric units, but also reduce long-wave heat radiation loss to improve heat collecting efficiency. The composite structure is sealed and fixed by an aluminum alloy frame and weather-resistant silicone to form a "glass-aerogel-battery" sandwich structure, which not only ensures high transmittance of visible light, but also blocks long-wave heat radiation loss, so that the battery operating temperature is stable at 25-40℃ (5-8℃ lower than the temperature of traditional photovoltaic components, and the conversion efficiency is increased by 1.5-2%).

[0036] Specifically, the thermoelectric power generation unit 3 is integrated with multiple thermoelectric modules, the hot end is connected with the heating area of the split infrared light beam, and the cold end can be temperature-maintained through the heat exchanger and the radiator to maintain stable temperature difference conditions and output direct current power.

[0037] Further, the thermoelectric power generation unit 3 is composed of 8 bismuth telluride-based thermoelectric modules (model: TEG12706, single module power ≥ 6W) in series, the hot end is aligned with the focusing area of the long-wave light reflected by the frequency splitting film 2 (focusing light power density is about 1000W / m 2 ), and the cold end is closely attached to the second heat exchanger 8 (plate heat exchanger, heat exchange area 0.5m 2 , heat exchange efficiency ≥ 90%); the hot end of the thermoelectric module is also covered with an anti-reflection coating 5 and an aerogel heat collecting and insulating layer 6 (parameters are consistent with the photovoltaic power generation unit), and the local greenhouse effect is used to increase the temperature of the hot end (stabilized at 80-100℃), and a temperature difference of 50-70℃ is formed between the cold end (30-40℃), to ensure that the thermoelectric conversion efficiency is ≥ 5%. The anti-reflection coating 5 is used in cooperation with the aerogel heat collecting and insulating layer 6 covered on the outside to further improve the light transmittance and heat collecting efficiency of the power generation unit.

[0038] In some embodiments, the energy storage system includes a heat storage circuit, a heat dissipation circuit and a matching control component, and realizes heat energy gradient storage and dynamic regulation.

[0039] Specifically, the heat storage circuit includes a first heat exchanger 7 (back of the photovoltaic unit, parameters are the same as those of the second heat exchanger 8), a second heat exchanger 8, a phase change energy storage device 9, a circulating pipeline 10 (polyurethane foam insulation, thickness 20mm, pipe diameter DN32), and a circulating pump 11 (variable frequency electric pump, flow rate 0.5-2m 3 / h, head 15m). The first heat exchanger 7 is connected with the outlet of the phase change energy storage device 9, the second heat exchanger 8 is connected with the inlet of the phase change energy storage device 9, forming a series circuit, and the working medium is driven by the circulating pump to successively absorb the waste heat of the photovoltaic unit and the thermoelectric unit and is transported to the phase change energy storage device 9 for storage.

[0040] Specifically, the heat dissipation circuit includes a three-way valve 12 (intelligent electric regulating valve, response time ≤ 1s), a radiator 13 (air-cooled, heat dissipation area 2m 2 , air volume 1500m 3h) and a throttle valve 14 (manual control valve, control accuracy ± 5%). The three-way valve 12 is installed on the circulating pipeline 10 between the outlet of the second heat exchanger 8 and the inlet of the phase change energy storage device 9, the first port is connected to the outlet of the second heat exchanger 8, the second port is connected to the inlet of the phase change energy storage device 9, and the third port is connected to the inlet of the radiator 13; the outlet of the radiator 13 is connected to the inlet of the first heat exchanger 7, forming a heat dissipation branch. The throttle valve 14 is respectively arranged in the heat storage circuit (before the inlet of the phase change energy storage device 9) and the heat dissipation circuit (before the inlet of the radiator 13), and cooperates with the three-way valve 12 to realize flow buffering and pressure regulation, avoiding energy impact during mode switching.

[0041] Further, the phase change energy storage device 9 has a cylindrical structure (diameter 800 mm, height 1200 mm), and inside it, from bottom to top, are sequentially arranged a high-temperature phase change material layer 901, a medium-temperature phase change material layer 902, and a low-temperature phase change material layer 903, each layer is separated by a heat insulation layer, and each layer is provided with a heat exchange pipeline, and the outer diameter D0=12-20 mm.

[0042] The parameters of each layer are as follows: The high-temperature phase change material layer 901 selects a polyethylene glycol-6000 (PEG-6000) composite phase change material, the phase change temperature is 40-60℃, the phase change latent heat is ≥250 J / g, and the layer thickness is 50-90 mm, which corresponds to the demand for building high-temperature hot water (50-60℃).

[0043] The medium-temperature phase change material layer 902 selects a paraffin-based composite phase change material (paraffin content 80%), the phase change temperature is 20-40℃, the phase change latent heat is ≥200 J / g, and the layer thickness is 70-120 mm, which corresponds to the demand for building heating in winter (25-30℃).

[0044] The low-temperature phase change material layer 903 selects a hydrated salt phase change material (Na2SO4·10H2O), the phase change temperature is 5-20℃, the phase change latent heat is ≥150 J / g, and the layer thickness is 40-70 mm, which corresponds to the demand for low-temperature insulation or auxiliary cooling in spring and autumn.

[0045] The heat insulation layer is composed of an aerogel composite felt layer (thickness 10-20 mm) and a glass wool layer (thickness 20-30 mm), and the total thickness is 30-50 mm, the thermal conductivity is ≤0.03 W / m·K, and the outer layer is an aluminum foil composite film as a protective layer. The aerogel composite felt layer ensures low thermal conductivity, the glass wool layer provides mechanical support and fireproof performance, and the aluminum foil composite film plays a role in waterproofing and radiation heat protection.

[0046] The device is internally provided with an internal spiral tube 904 made of copper-nickel alloy (model: Cu-Ni 90 / 10), with an outer diameter of 12-20 mm and a spiral spacing of 50 mm, and the tube is filled with water-glycol mixed working medium (volume ratio: 7:3 in North China in winter, 5:5 in severe cold regions, and the freezing point is as low as -37°C), so as to realize heat transfer between each phase change layer and the heat exchanger, meet the winter anti-freezing requirements in most regions, and ensure the safe operation of the system.

[0047] Further, the system is provided with a PLC intelligent control unit (model: Siemens S7-1200), which is integrated with multiple types of sensors: an illumination intensity sensor (TSL2561, measurement range 0-100000 lux, accuracy ±5%); a temperature sensor (DS18B20, measurement range -55-125°C, accuracy ±0.5°C), which is arranged on the surface of the photovoltaic unit, the hot end / cold end of the thermoelectric unit, each layer of the phase change energy storage device, and indoors and outdoors; an electric power sensor (current and voltage integrated, measurement range 0-500V / 0-10A, accuracy ±0.2%); a flow sensor (electromagnetic type, measurement range 0-5m³ / h, accuracy ±1%); the control unit automatically executes operation mode switching, circulating pump speed regulation, three-way valve on-off control by collecting the above parameters, and supports RS485 communication interface and building energy management platform networking, realizes remote monitoring, data storage (storage period ≥1 year) and energy efficiency optimization (target makes the system annual energy self-sufficiency rate ≥60%).

[0048] Example 1: Heating season operation mode (North China winter, outdoor temperature -10-10°C, building needs heating and hot water) 1. Optical and energy conversion process: sunlight is focused by Fresnel lens 1 (concentration ratio 10:1), when passing through the frequency division film 2, 300-800nm short wave light is transmitted to the photovoltaic power generation unit 4, which is converted into direct current (daily average power generation about 2kWh), which is preferentially supplied to building lighting and household appliances (the remaining electric energy is connected to the grid through an inverter); 800-2500nm long wave light is reflected to the thermoelectric power generation unit 3, which heats the hot end to 90°C, and the cold end (35°C, cooled by the second heat exchanger 8) forms a temperature difference of 55°C, and the thermoelectric module generates about 0.5kWh of electricity per day, which supplements the building power consumption.

[0049] 2. Waste heat storage and heating process: the intelligent control unit controls the three-way valve 12 to switch to "heat storage mode" (the first port is connected to the second port, and the third port is closed), the circulating pump 11 is started at 1.5m / s, and the phase change energy storage device 5 is heated to 55°C, and the heat is stored in the form of latent heat and sensible heat. 3The water-ethylene glycol working fluid flows through the first heat exchanger 7 (absorbing the waste heat of the photovoltaic unit, the temperature rising from 30°C to 35°C), the second heat exchanger 8 (absorbing the waste heat of the thermoelectric unit, the temperature rising from 35°C to 55°C), and the phase change energy storage device 9 (heating the high-temperature layer 901 to 50°C and the medium-temperature layer 902 to 30°C), forming a cycle. When the high-temperature layer of the phase change energy storage device 9 is completely phase changed (storing about 50 kWh of heat), the control unit starts the heating terminal 15 (the floor heating coil, the water supply temperature being 30-35°C), and the working fluid is transported to the floor heating after being heated by the medium-temperature layer of the phase change energy storage device 9, meeting the building heating demand (the daily average heat consumption being about 30 kWh); the hot water is supplied by heating the high-temperature layer, the water supply temperature being 50-55°C, and the daily average water supply being about 100 L.

[0050] 3. Night heat supplement process: when there is no light at night, the circulating pump 11 runs at a flow rate of 0.8 m 3 / h, the working fluid absorbs the heat released by each layer of the phase change energy storage device 9, and is used for building heating and hot water supply in turn, until the next day when the sunlight is restored, ensuring that the indoor temperature is stable at 18-22°C at night.

[0051] Example 2: cooling supply mode (summer in East China, outdoor temperature 25-35°C, building without heat demand, and electricity generation is preferred) 1. Optical and energy conversion process: after the sunlight is focused by the Fresnel lens 1, the short-wave light separated by the frequency separation film 2 drives the photovoltaic power generation unit 4 to generate electricity (the daily average power generation being about 2.5 kWh, which is increased by 25% in summer due to strong light); the long-wave light drives the thermoelectric power generation unit 3, and the hot end temperature rises to 95°C, at this time, if there is no heat dissipation, the cold end temperature will rise to 45°C, the temperature difference will decrease to 50°C, and the thermoelectric efficiency will decrease to 4.5%.

[0052] 2. Heat dissipation and electricity generation optimization process: the intelligent control unit detects that there is no heat demand in the room (the indoor temperature being ≤ 26°C), controls the three-way valve 12 to switch to the “heat dissipation mode” (the first port → the third port being open, and the second port being closed), and the circulating pump 11 runs at a flow rate of 2 m 3 / h, the working fluid flows through the second heat exchanger 8, the temperature rising from 40°C to 60°C, enters the radiator 13, is cooled to 35°C by air cooling, and then flows through the first heat exchanger 7 to absorb the waste heat of the photovoltaic unit (the temperature of the photovoltaic unit decreasing from 35°C to 30°C, and the conversion efficiency increasing by 1%), forming a cycle; at this time, the cold end temperature of the thermoelectric unit is stable at 35°C, and a temperature difference of 60°C is formed with the hot end (95°C), the thermoelectric efficiency is maintained at 5%, and the daily average power generation is about 0.6 kWh; the total daily average power generation of the photovoltaic and thermoelectric units is about 3.1 kWh, and the excess electricity (about 1.5 kWh) is connected to the grid, meeting 30% of the building air conditioning electricity demand in summer.

[0053] Embodiment 3: Transition season operation mode (spring season in East China, outdoor temperature 10-20℃, building heat load fluctuates greatly) 1. Dynamic mode switching logic: the intelligent control unit collects indoor temperature (set threshold 18-24℃) and phase change energy storage device 9 storage (set threshold: full capacity 80%, low capacity 20%) in real time: When the indoor temperature is less than or equal to 18℃ (heating is needed) and the phase change energy storage device 9 storage is greater than or equal to 20%, the three-way valve 12 switches to the "heat storage-heat supply mode", and the working medium preferentially delivers residual heat to the phase change energy storage device 9, and then releases heat to the heat supply terminal 15 according to the heating demand; When the indoor temperature is greater than or equal to 24℃ (heating is not needed) and the phase change energy storage device 9 storage is greater than or equal to 80%, the three-way valve 12 switches to the "heat dissipation mode" to avoid overheating of the heat storage device; When the light intensity is less than or equal to 20000 lux (overcast day), the circulating pump 11 reduces the speed to 0.5m 3 / h to reduce energy consumption, and at the same time the phase change energy storage device 9 releases heat to maintain building basic electricity and insulation demand.

[0054] 2. Operation effect: in the transition season (April and October), the system generates about 1.8kWh of electricity per day, stores about 20kWh of heat per day, and the building energy self-sufficiency rate is greater than or equal to 50%, which is 15-20% higher in energy efficiency than the traditional solar system (without spectrum separation and cascade heat storage).

[0055] The present embodiment realizes the following technical effects through the organic combination of optical frequency division, thermoelectric cooperation, cascade heat storage and intelligent control: The present application breaks through the technical bottlenecks of "insufficient spectrum utilization, single energy output form, simple heat storage structure, and rigid system operation mode" in the traditional solar building energy system by constructing a solar building energy system integrated with spectrum separation, photovoltaic power generation, thermoelectric power generation, multi-temperature zone heat storage and intelligent control, realizing light, heat and electricity multi-path cooperation, high efficiency conversion and multi-scene adaptation, and having significant technical advantages and wide application prospect.

[0056] Firstly, the present application separates the focused sunlight by wavelength by setting a frequency separation film, directs the visible light part into a photovoltaic module to realize photoelectric conversion, and directs the infrared long wave part to a thermoelectric unit to generate power by temperature difference, effectively avoiding the spectrum interference between the traditional photovoltaic-photothermal system, realizing the efficient and collaborative utilization of full-band and multi-function of solar energy. This spectrum functional design significantly improves the comprehensive energy efficiency under unit area sunshine, and the advantage is more obvious especially in the building environment with large annual sunshine variation and strong heat load fluctuation.

[0057] Secondly, the present application innovatively couples the thermoelectric conversion unit with the multi-temperature-zone phase change heat storage device, breaking the dependence on large temperature difference and continuous heat source in traditional thermoelectric systems. The multi-level phase change material is distributed according to temperature zones, which can not only store the excess heat energy in the daytime in stages, but also release heat to multiple ends such as domestic hot water, building heating or auxiliary power generation as needed, effectively improving the scheduling accuracy and utilization efficiency of heat energy. The internal spiral heat exchange structure of the energy storage device enhances the heat coupling efficiency and improves the response speed of the system.

[0058] Furthermore, the system has the ability of adaptive operation switching based on seasons and environment. Through the logical linkage of the electric three-way valve and the circulating pipeline, the system can intelligently switch between operation modes such as "power generation + heating", "power generation + cooling", and "heat storage priority", to meet various demands such as winter heating, summer cooling, and power priority in intermediate seasons. Especially in areas with significant seasonal changes, this adaptive strategy can effectively avoid energy waste and reduce operating efficiency.

[0059] In addition, the present application adopts modular and high-integration design, and the optical, heat exchange, power and control module structure is compact, which can be installed in limited space such as building roof and balcony, with less land occupation, flexible layout, especially suitable for the modification or new construction demand of urban buildings. At the same time, the system supports the extension configuration of photovoltaic and thermoelectric modules, and has good upgradeability and engineering application adaptability.

[0060] Finally, the system is configured with an intelligent control unit, integrating multiple types of sensors and automatic control logic, which can realize real-time monitoring, data collection and scheduling optimization of the system operation state, and supports remote control and platform access, providing interface support for smart energy systems. The overall operation of the system is clean, low-carbon and safe, which meets the mainstream direction of green building and renewable energy integration development, and has good energy saving benefit, social benefit and promotion value.

[0061] In summary, the photovoltaic-thermal energy storage multi-element coupling system of the present embodiment effectively solves the problems of low spectral utilization, poor seasonal adaptability and insufficient energy storage capacity of traditional solar systems, and provides an engineeringable technical solution for clean and intelligent building energy.

[0062] According to the description and drawings of the present application, those skilled in the art can easily manufacture or use the photovoltaic-thermal energy storage multi-element coupling all-weather adaptive building energy system and method of the present application, and can produce the positive effects described in the present application.

[0063] Unless otherwise defined, all terms used in disclosing aspects of the application, such as professional terms and technical terms, have the meanings as commonly understood by one of ordinary skill in the art to which this application belongs. By way of non-limiting example, the following definitions are provided.

[0064] Unless otherwise defined, all terms used in disclosing aspects of the application, such as professional terms and technical terms, have the meanings as commonly understood by one of ordinary skill in the art to which this application belongs. By way of non-limiting example, the following definitions are provided.

[0065] The above description is only the preferred embodiment of the application, not any form of limitation on the application, any simple modification, equivalent change of the above embodiment according to the technical essence of the application, falls within the protection scope of the application.

Claims

1. A photovoltaic photo-thermal energy storage multi-element coupling all-weather self-adaptive building energy system, characterized in that, The application relates to a solar energy conversion system, which comprises the following components: a Fresnel lens (1) for focusing sunlight; a frequency separation film (2) arranged on the light path of the Fresnel lens (1) for separating sunlight into short-wave light and long-wave light according to wavelength; a photovoltaic power generation unit (4) for receiving the short-wave light and performing photoelectric conversion; a thermoelectric power generation unit (3) for receiving the long-wave light and heating a working medium and generating electricity by utilizing temperature difference; an energy storage system connected with the photovoltaic power generation unit (4) and the thermoelectric power generation unit (3) respectively, for storing heat energy generated in the process of power generation and releasing heat according to requirements.

2. The photovoltaic photo-thermal energy storage multi-element coupled all-weather self-adaptive building energy system according to claim 1, characterized in that, The light-receiving surface of the photovoltaic power generation unit (4) and the hot end of the thermoelectric power generation unit (3) are sequentially covered with an anti-reflection coating (5) and an aerogel heat collection and heat preservation layer (6) from inside to outside.

3. The all-weather self-adapting building energy system of photovoltaic photo-thermal energy storage and multi-element coupling according to claim 2, characterized in that, The anti-reflection coating (5) is composed of one or more materials selected from SiO2, MgF2 and TiO2, has a thickness of 100-120 nm and a reflectivity of not higher than 5%.

4. The all-weather self-adapting building energy system of poly-element coupling of photovoltaic photo-thermal energy storage according to claim 2 or 3, characterized in that, The aerogel heat collection and heat preservation layer (6) is high-transmittance silica aerogel, has a thickness of 5-20 mm, a visible light transmittance of not lower than 80% and a thermal conductivity coefficient of not higher than 0.02 W / m*K. 5.The all-weather self-adapting building energy system of photovoltaic photo-thermal energy storage and multi-element coupling according to claim 1, wherein, The energy storage system comprises a heat storage circuit, the heat storage circuit comprises a first heat exchanger (7), a second heat exchanger (8), a phase change energy storage device (9), a circulating pipeline (10) and a circulating pump (11), the first heat exchanger (7) is arranged on the back surface of the photovoltaic power generation unit (4), the second heat exchanger (8) is arranged on the cold end of the thermoelectric power generation unit (3), the outlet of the second heat exchanger (8) is connected with the inlet of the phase change energy storage device (9), the inlet of the first heat exchanger (7) is connected with the outlet of the phase change energy storage device (9), and the two heat exchangers are connected in series.

6. The photovoltaic photo thermal energy storage multi-element coupled all-weather self-adaptive building energy system according to claim 5, characterized in that, The energy storage system further comprises a heat dissipation circuit, the heat dissipation circuit comprises a three-way valve (12) and a radiator (13), the three-way valve (12) is installed on the circulating pipeline (10) of the heat storage circuit, the first port of the three-way valve (12) is connected with the outlet of the second heat exchanger (8), the second port is connected with the inlet of the phase change energy storage device (9), the third port is connected with the inlet of the radiator (13), and the outlet of the radiator (13) is connected with the inlet of the first heat exchanger (7).

7. The photovoltaic photo thermal energy storage multi-element coupled all-weather self-adaptive building energy system according to claim 6, characterized in that, The circulating pipeline (10) of the heat storage circuit and the heat dissipation circuit is provided with a throttling valve (14). 8.The all-weather self-adapting building energy system of photovoltaic photo-thermal energy storage and multi-element coupling according to claim 5, wherein, The phase change energy storage device (9) comprises a high-temperature phase change material layer (901), a medium-temperature phase change material layer (902) and a low-temperature phase change material layer (903) arranged in sequence, and an internal spiral pipe (904) penetrating through the layers; heat insulation layers are arranged between the layers, and heat exchange pipelines connected with different heat supply ends (15) are arranged in the layers. 9.The all-weather self-adapting building energy system of photovoltaic photo-thermal energy storage and multi-element coupling according to claim 8, wherein, The phase change temperature of the high-temperature phase change material layer (901) is 40-60℃, and the latent heat of phase change is not less than 250J / g; the phase change temperature of the medium-temperature phase change material layer (902) is 20-40℃, and the latent heat of phase change is not less than 200J / g; the phase change temperature of the low-temperature phase change material layer (903) is 5-20℃, and the latent heat of phase change is not less than 150J / g; the heat insulation and heat preservation layer is one or more laminates of aerogel composite felt, glass wool or polyurethane foam, the thickness is 30-50mm, and the thermal conductivity is not higher than 0.03W / m·K.

10. A method for operating the all-weather self-adapting building energy system of poly-element coupling of photovoltaic, photo-thermal and energy storage according to any one of claims 1-9, characterized in that, The method comprises the following steps: In the heating season, sunlight is focused by the Fresnel lens (1), and after the frequency separation film (2) separates the wave bands, the short wave is introduced into the photovoltaic power generation unit (4) to generate electricity, the long wave is introduced into the thermoelectric power generation unit (3) to generate electricity, and at the same time, the heat working medium is guided to flow into the phase change energy storage device through the three-way valve (12) and to heat the heating terminal (15) or to supply hot water; In the cooling season, when the building has no heat demand, the heat working medium is guided to flow into the radiator (13) through the three-way valve (12) to reduce the cold end temperature of the power generation unit; In the transition season, the system intelligently distributes heat to the heat storage circuit or the heat dissipation circuit according to the real-time energy consumption demand, balances the heat storage and heat dissipation demand.

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