Solar Air Collection-Storage Technology Research For Room Heating In Northern China Shallow Hills Region

Solar energy is a widely distributed, renewable green energy. However, the sun radiationis always affected by day and night, seasons, rain and snow and other weather factors.Therefore, collecting and storage of solar energy are equal important especially when it isused for room heating. A solar air collector is a device to absorb solar radiation by plate and toheat air, it is a simple way for room heating. As solar radiation is fluctuating in a day, tocombine a solar energy collector and thermal storage device is a reasonable way in solarthermal utilization.This thesis investigated the solar air collector with thermal storage device theoreticallyand experimentally. Mathematical model of phrase changing process of paraffin encapsul ballwas established and simulated by both Matlab and Fluent; melting and condensing time andthe diameter of the parrifin ball was analyzed.Many factors might affect the solar air thermal collection-storage device, there are16possible design schemes designed by orthogonal experiment method. Each scheme simulatedand analyzed by FLUENT software. The best design and running parameters obtained withthe maximum thermal storage efficiency. The optimal parameters are: the entrance flow rate is1.6m/s; cover plate is double layer of high transparent glass; the entrance air temperature is263.15K; the air layer thickness is80mm, and the thickness of thermal storage material is80mm; the maximum solar radiation intensity is592.2W/m~2at noon.Based on the theory research, a test bed was build and tested. The structure and thermalcharacteristics of the solar air thermal collection-storage device tested relatively, including thecollector plate, natural and forced convection of the air layer and thermal storage materials.Experimental results verified that the air layer thickness between70mm and90mm isappropriate choice. Under static condition, the average thermal collection efficiency of thesolar air thermal collection-storage device is64%; while the device without thermal storagematerials, the average collection efficiency is24%. In dynamic condition, thermal collectionefficiency of the solar air thermal collection-storage device is ranged38%to56%; and thedevice without heat storage materials, the collection efficiency is ranged30%to61%. Besides,thermal storage efficiency of the solar air thermal collection-storage device is at the ranged21%to25%. The experimental research also verified the numerical simulations.