EXPERIMENTAL STUDY ON THE THERMAL EFFICIENCY OF THE FORCED CONVECTION EVACUATED TUBE SOLAR AIR COLLECTORS WITH AND WITHOUT ABSORBER PLATE
For the present world, the energy requirement is very high. To fulfill the demands for energy in future, renewable source energy is used. As the usage of fossil fuel was increased, it causes more pollutants in the environment. In considering the above factors, cost effective alternate energy is being developed. Solar energy is one of its best energy sources. The current methods of industrial process heating employ huge amount of fossil fuel which in turn increase the import of fuels. Shifting the methods to greener technologies give potential savings in foreign exchange and reduction in dependence of fuel from other countries. The proposed technologies clearly shows the industries can get a good amount of cost saving immediately (lower payback period) and also emission control contributing to lower carbon foot prints. Drying of agricultural food products is one of the most attractive and cost–effective application of solar energy as it becomes a potentially viable substitute for fuel-wood in much of the developing world. Numerous types of solar dryers have been designed and developed in various parts of the world, yielding varying degrees of technical performance. The objectives of the experiment were to investigate the thermal performance on evacuated tube solar air collector with and without absorber plate by testing various air flow rates. The experiment consists of four main parts such as evacuated tube, manifolds, blower, and absorber plate. Evacuated tube collector based air heating system has 30 Numbers of modules having 4.8 m2 apparatus area. The manifold channel consists of two parts. The first part is made up of Outer hollow circular tube and second part by inner circular tube. Air is made to flow through inside tub, he processed to heat, then by pressure difference the air flows through the outside manifold. The proposed innovative system i.e., evacuated tube solar air collector to reduce the auxiliary power (Blower) requirement, since the air flow friction through evacuated type collector is very high in magnitude, it draws high blower power requirement. The absorber plate is made up of aluminum block coated sheet. The performance efficiency of the solar air collector evacuated tubes increased by enhanced absorber plate which is inserted at the bottom of the evacuated tube. Comparing with evacuated tube solar air collector without absorber plate, high outlet temperature and better efficiency is seen with the absorber plate.
S. BABU SASI KUMAR AND M. CHINNAPANDIAN