EFFECT OF SOME PARAMETERS ON LINEAR FRESNEL SOLAR CONCENTRATING COLLECTORS

Solar concentrating systems are best suited for medium-grade (60-250°C) thermal applications. The absorber of the linear solar concentrating device play very important roll in collection of solar energy. The non-evacuated solar absorber painted with ordinary black paint yield poor performance. To achieve higher efficiency of the solar collector, there should be minimum thermal losses from the absorber. The overall heat loss coefficient of the absorber includes convection, radiation and conduction heat losses. Surface coating on the absorber surface, glass cover, shape and size of the absorber surface, temperature of the absorber etc. affects thermal performance of the absorber. Transparent glass cover at bottom allows light entry and at the same time reduced heat loss due to wind. Rise in oil temperature with increase in number of mirrors, but the increase was not found to be linear. The time required to reach peak temperature reduced proportionally with increase in number of mirrors.