An Experimental Study of Natural Convection Heat Loss from a Solar Concentrator Cavity Receiver at Varying Orientation

Convection losses are an important determining factor in the performance of solar thermal power systems with cavity receivers such as those used in paraboloidal dishes. An experimental investigation based on an isothermal electrically heated model receiver, is in progress. The convection loss of the model receiver has been measured at inclinations varying from 0 (cavity aligned horizontally) to 90(cavity facing straight down). The results show that the maximum convection loss occurs at 0 and is a minimum at 90. Numerical analysis of the problem shows good agreement while most previous empirical correlations over predict the losses.