Thermal performance of one-ended evacuated tube solar air collector at different flow rates: experimental investigation

A solar-powered air heating system using one-ended normal evacuated tubes is experimentally investigated and used for heating. In this experimental setup, a header which works as a heat exchanger has been used. The header consists of a hollow pipe (circular pipe) in the centre through which the air flows. The experimental setup contains a fluid which works as a heat-collecting medium and collects the solar heat which falls on the tubes. This heat is delivered to the air flows through the circular pipe. To enhance the outlet temperature, copper coil and reflectors are used. Both configurations of parallel and counter flows are experimentally examined by changing the position of the blower. It is found that the setup operates more efficiently at high flow rate and counter flow, in the model with reflector and coil. The attained maximum temperate difference is found to be 36.8 degrees C at a flow rate of 0.0268 kg/s.