Analysis Of Optimal Thermal Process Of Building Integrated With The Solar Air Collector

Solar air collector is a kind of the economic, high-performance solar energy equipments for heating in winter.At present, the problems such as the low efficiency of solar air collector, overheating in summer and the impact on the appearance of the building restrict its application in buildings. However, lots of researchers focused on the thermal performance of solar air collector, and there are few studies concerning the whole year operation of solar air collector and its integration with the buildings.In this study, the heat efficiency, air circulation characteristics and the approach of the integration with the buildings are investigated. By field measurement and theoretical calculation, several constructive and useful conclusions can be obtained as follows:1) Based on the former research results, and considering the improvement of the collector efficiency and the elimination of the overheat problem in summer, the porous flat-plate solar air collector with baffle board is proposed and used as the form for a whole year operation. Compared with the traditional form, the efficiency of the porous flat-plate solar air collector increases 50%. Furthermore, mechanical exhaust with inner shading is concluded to be the best way to avoid overheat for solar air collector in summer. The heat efficiency of solar air collector can reach more than 75%, and the cooling load of south wall installed the collector is 12.5 percent of that for the collector without exhaust in summer. 2) Combining the field measurement, this study sets up a porous flat-collector model to predict the air temperature at the collector outlet. The optimization approaches for the solar air collcetor are discussed and thermal performance of the optimal collector in winter is predicted. The results show that heat supply of the solar air collector can meet the heat load of the building with the energy-saving of 65% demand with its aspect ratio of 6 and the ratio of inner air gap thickness to the outer air gap thickness of 3 and the solar radiation intensity greater than 230W/m~2. In the case, 0.011kg standard coal can be saved for 1 square meter of building area by calculation. For a six-storey, four-units building in Dalian, 3032.64kg standard coal could be saving in a heating period. The results from this study offer some important information for solar air collector design, and have great significances and application value for developing solar energy technology.