Experimental Study Of A Building Envelope System Integrating Solar Panels And Thermoelectric Modules

Faced with the crisis of the depletion of fossil fuels and environmental pollution,a novel building envelope system integrating solar panels and thermoelectric modulesis proposed, given that solar energy is abundant, clean, non-polluting and thermo-electric cooling technology is with small size, but without refrigerant. In the system,the solar panels transfer solar energy into DC power, which can be directly used todrive the thermoelectric modules. Then, the cold or heat generated by the thermo-electric modules is passed to the indoor by radiant panel. The system can meet thedual demands of cooling in summer and heating in winter of buildings.Since the thermoelectric modules generally work stablely under the design stateof maximum cooling capacity or maximum cooling coefficient. But in the buildingenvelope system integrating solar panels and thermoelectric modules, the instantan-eous output power of solar panels fluctuate with the change of solar irradiance,resulting in the thermoelectric modules operating under off-design conditions. To testthe performance of the thermoelectric modules under off-design conditions, a DCpower device instead of the solar panels is used to output unstable current to drive thethermoelectric modules. The results show that the thermoelectric modules refrigeratefast with a strong anti-jamming capability, and can be able to maintain a stableworking performance when its operating voltage and operating current are constantlychanging. Under the experimental conditions, the optimum operating voltage range ofthe thermoelectric modules is between4V and6V, because the cooling capacity ismaximum and the cooling efficiency is more appropriate at this time. In addition,since the heating efficiency is about0.8higher than the cooling efficiency, so we cantake full advantage of its high heating efficiency.In this paper, the studies focuse on the performance of cooling and thermalinsulation of the building envelope system integrating solar panels and thermoelectricmodules. Firstly, the influence of the inclination of the solar panels and the solarirradiance on the building envelope system is analysed. Then, the performance ofcooling and thermal insulation of the building envelope system integrating solarpanels and thermoelectric modules is compared with that of the traditional brick wall.The results show that the conversion efficiency of the solar panels is higher when thepower consumption of the external load and the output power of the solar panels are preferably matched. Under the tilt angle of25degrees, the conversion efficiency ofthe solar panels and the cooling capacity of the thermoelectric modules are bothhighest, which indicates that the performance of cooling and thermal insulation of thebuilding envelope system integrating solar panels and thermoelectric modules is best.The stronger the solar irradiance, the greater the output power of the solar panels, themore the cooling capacity of the thermoelectric modules, the better the performanceof cooling and thermal insulation. Compared with the traditional brick wall, theaverage temperature of radiant panel of the building envelope system integrating solarpanels and thermoelectric modules is15~17℃lower than that of the outdoor brickwall,6~8℃lower than that of the indoor brick wall. Thus, the performance of coolingand thermal insulation of the building envelope system integrating solar panels andthermoelectric modules is superior to that of the traditional brick wall. Not only canthe system effectively block the heat transmitting from outdoor to indoor, but also canprovide a certain amount of cold to the indoor and reduce the energy consumption ofair conditioning in summer.