The Experimental Study On Performance Of Feed-Tube Evacuated Tubular Solar Air Heater

The thermal and flow performance of flat plate and evacuated tube collectors was investigated on this paper. A elementary configuration was determined for feed-tube solar air heater. The heat transfer and flow mechanism was studied experimentally and analytically using air as the working fluid.The influence of geometric parameter of the feed tube was studied experimentally, a optimal size was found for the best performance.A discreet hydrodynamic model was used to determine the flow distribution in a parallel-reverse solar collector. The size of manifolds was determined by calculation.The time constant and instantaneous efficiency of the feed-tube solar air heater were tested on the solar irradiance.The equation for instantaneous efficiency was obtained at the different flow rate.At last, through studying the corresponding testing standard, a standard text for testing the thermal performance of evacuated air heater was put forward based on experiment.