The Experimental Research On Thermal Performance Of Flat-Plate-Type Heat Pipe Solar Air Collector

Currently, Solar energy is clean, resourceful and inexhaustible. Solar thermal utilization has been the most efficiency and maturest technology above the various kinds of solar energy exploit in the time. Solar air collector, as the key thermal-absorbed components in the solar energy heat utilize, has an immense applications in the fields of indoor heating, ventilation and products drying.Heat pipe owns such excellent features as higher transfer coefficient, lower transfer temperature-difference and a one-way transfer, etc. A new flat-plate-type heat pipe solar air collector was designed and built in this thesis, with thermal-absorbed and transfered device of heat pipe. The theoretical analyzes about the thermal performances was gaved and the experiment device for daily average thermal performance was finished.With the records of solar radiation, temperature and humidity of environment and inlet or outlet air temperature of air collector exchanged by the time in any circumstance by orthogonal experiment, we can get day-averaged thermal efficiency, heat loss coefficient and instantaneous thermal efficiency of the new collector and analyze the thermal efficiency under different solar radiation, inlet air temperature and air flow rate in flow channel. The conclusions are as follows:(1) Air temperature-difference from inlet and outlet of the collector is 1.8 to 49.2℃ with total solar radiation of 14.4 MJ/m2-19.8MJ/m2 daily, and the maximum air temperature from outlet can reach 79.1＞, day-averaged thermal efficiency can get 32.6%-53.5%, the instantaneous thermal efficiency is 15.3%-74.5%.(2) The day-averaged thermal efficiency under air flow mass rate of 46.1 kg/ h·m~2 can reach 52.3%-53.5%, air temperature-difference from inlet and outlet of the collector is 2.1 to 43.9℃, and the maximum air temperature from outlet can reach 79.1 ℃, heat loss coefficient being 3.6-8.4W/(m~2·K) while the air temperature from outlet is 30℃-80℃.(3) The thermal efficiency of solar air collector, dropping with the air temperature from inlet raised, soared and stabled finally with the air flow rate increased, increases to the peck and dropps down with the solar radiation increased.(4) The air temperature from outlet in the flow channel of solar air collector, dropping with the air flow rate increased, soared with the solar radiation increased, increases with the inlet-air temperature and heated time raised, as well as the temperature on the face of heat pipes.