Study On Prabolic Through Solar Collection And Its Utilization

Parabolic trough solar collector (PTC) is one type of the intermediate/high temperature collectors. It is widely used in the field of electricity generation, air-conditioning, heating,desalination and so on. Conventional absorber used in PTC is the vacuum tube. It contains an interior metallic tube and an exterior glass tube. The working fluid flows in the metallic tube, and there is spectrally selecting absorption coating on its surface. It is kept vacuum between the metallic and glass tube to restrain thermal loss. Because of different expanding coefficients, the cost of vacuum tube absorber is relatively high, and it useful life is short. A new cavity absorber in this paper is investigated, and its thermal loss is constrained by the cavity radiation.This paper discusses 4 different types (triangle, square, circle,hemi-circle) of cavity absorber from the aspects of analog computation and experiment. Analog computation contains the thermal performance analysis based on FLUENT software and optical performance simulation based on TracePro. The effect analysis of absorb surface temperature (90℃/150℃), tilt angle (α) and different glass covers on thermal performance has also been taken. In the experiment research, optical efficiency and optimal opening width test system has been built. The results show that the triangle cavity has the best optical performance. Then the thermal loss (indoor) and thermal efficiency experiments in which solar energy is replaced by electricity heat pellicle has been carried on, the results aslo show that triangle cavity has the optimal thermal performance. Its thermal efficiency is 65.8% when Ti=90℃and when condense width is 3m(optical efficiency is 70%). The circle cover (compared with plant PB and V type covers)has the minimal thermal loss coefficient which is 1.3635W/m2.K. In the end, a geothermal-solar power generation system, which is based on PTC has been analyzed. A feasibility analysis of this combined system with fixed solar collector area (1000 m2) which is used in Tibet has been carried out. It shows that the hybrid system produces 10% more electric power output than that of geothermal-only power plant.