An analysis of convective losses from cavity solar central receivers

Abstract An analytical model is presented which enables the estimation of convective losses from cavity receivers. Evidence from solar experiments is used to test the hypothesized mechanisms. The analytical results and experimental evidence indicate that the convective loss from cavity receivers is appreciable. The model indicates that the influences of the wind on the convective loss at normal operating conditions are minimal. It also shows that the internal thermal resistances, i.e. the ability to heat the air inside the cavity, are of greatest importance. Buoyancy induced flows are, on the other hand, very effective in transferring energy across the aperture.