Numerical study on thermal performance of a solar cavity receiver with different depths

Abstract

Solar cavity receiver usually has an aperture for concentrated sunlight coming in. However, there is apparent heat loss because of this aperture. And the asymmetric approach of energy supply causes highly non-uniform distribution of heat flux inside the cavity. As a result, it is necessary to investigate geometrical effects on thermal performance of the receiver. A saturated water/steam solar cavity receiver with different depths was numerically studied by adopting a combined computational model. The variation trends of thermal efficiency and heat loss with depths were obtained. The influential factors on the change of three kinds of heat loss were specifically analyzed. The net energy absorbed by the boiling panels, the mass flow rate of generated steam and the distributions of heat flux and wall temperature on the boiling panels were also figured out. The results showed that a peak thermal efficiency exists as the receiver is stretched. And the distribution of heat flux on the boiling panels appears more and more uniform with the stretched length increasing. A suitable cavity depth was finally found for the receiver studied in the present work.