Integration Study On Solar Hot Air Heating System With Village Buildings

Solar thermal technology is an important way to use solar energy and its rational use could effectively solve the prolem of energy shortage. Solar hot air heating system with its superior features, could make up shortcomings of solar hot water system, such as investment, freezing, leakage, slow startup, etc, and should be widely used. For this, this paper studied integeration of solar hot air heating sysem with villages building, mainly to optimize structural and import parameters of system.Firstly, on the basis of Solar Wall designed by Conserval Corporation, the paper proposed a new type of collector - unglazed transpired air collector with slit-like perforations. Through mathematical model built, external parameters on its thermal efficiency were analyzed.Secondly, in view of shortcomings of unglazed transpired air collector with slit-like perforations, the paper further proposed a glazed transpired collector with slit-like perforation, and studied performance of collectors respectively with ordinary and vacuum glass cover theoretically and experimentally. Here, effective efficiency was raised and combined with thermal efficiency and temperature difference of air inlet and outlet as evaluation indexes, to find out optimized values of structural and import parameters. Using experimental results, empirical relationship of local resistance coefficient was regressed, which proved the collector's superiority. Compared ordinary glass cover collector to vacuum-type, the performance of latter was found to be better.Thirdly, considering characteristics of system working medium and villages, the paper determined pebbles as heat storage material. Taking average heat storage power and pressure loss as evaluation indexes, structural and import parameters on the regenerator performance were studied.Fourthly, requirements of solar building on site and building configuration were summarized, and impact of window opening form and angle on building energy-saving and natural ventilation were analyzed. In view of vital importance of shading on summer heat-resistant, the paper developed an executable programming for visualization design of roof overhang, providing a convenient, practical operational tool for different building structure and size.Finally, using frequency domain regression method to calculate response coefficients, the paper established dynamic heat balance equations of building, which was verified by experimental results. On the basis of study on air collector and regenerator, the paper took a building with rational configuration as simulation object, and analyzed effects of collector area, regenerator volume and absorber plate emissivity on solar fraction. The results showed that on the promise of economic conditions permit, collector area should be increased, and with constant collector area, there existed proper regenerator volume. Besides, selectively coating should be mainly studied, which was very important for system performance. Overall, if designed reasonally, solar fraction of hot air heating system was very high, and in view of its economic, it should be popularized in village buildings, which could accelerate the work of energy saving and emission reduction in villages.