Thermal Efficiency Test of Locally Manufactured Solar Flat Plate Collector of Nepal

Solar energy is a perpetual source of energy which is vital for maintenance of the earth system. Solar flat plate collectors have been one of the major innovations for converting solar energy into usable energy form. However, the innovations and R&D regarding this is lacking in Nepal. The study was thus carried out to know the present status of flat plate collectors manufactured in Nepal in terms of their thermal performance and also to envisage some guidelines for efficiency enhancement. The efficiency calculations of local flat plate collectors were done through experimental activities on the site followed by mathematical calculations and analysis. The average efficiency obtained experimentally was 0.39. The value of solar radiation was recorded up to 963 W/m(2) and mass flow rate was in the range of 1.8-9.7 g/s. Some guidelines for local manufacturers were attempted to be suggested in terms of tube spacing, insulating material, insulation thickness, material for absorber plate, number of glass cover, mass flow rate and plate to cover spacing. The collector design efficiency was obtained through the study of design parameters of flat plate collectors followed by simulation. The collector design efficiency was determined to be 0.54. The provided guidelines, if followed, can increase the efficiency of solar collectors to about 0.61.