End-Effect of Linear Fresnel Collectors

Linear Fresnel collectors usually have wider apertures and higher receivers in comparison with parabolic trough collectors. The end-effect of the receiver is very important, especially in small-scale linear Fresnel collector fields. The equations for estimating the end-effect for the north-south and east-west linear Fresnel collectors were derived from analyzing the angles between incident sunlight and the tacking axes of the mirrors. The end-effect varies with mirror focal distances for the north-south collector field at solar noon on monthly average days and with time of the day for the east-west collector field at latitude 25°01´N are discussed.