Transient thermal modelling and optimization of a solar collector-type pond considering an improved decay of radiative intensity

Abstract

In the present work, an improved expression of the radiative intensity decay in solar ponds is proposed through an equivalent absorption coefficient calculated using Beer-Lambert's law. Based on the improved expression, a transient thermal model involving side and bottom heat losses is developed for a solar collector-type pond consisting moving storage zone. Thereafter, the effects of various thermophysical parameters on instantaneous and steady state efficiencies are studied. Finally to maximize the efficiency, simultaneous optimization of lower and middle zones of the pond is proposed. It is highlighted from the present study that the proposed expression of computing radiative intensity overcomes practical drawbacks of earlier models. The optimization also reveals that without its aid, practically unrealizable performance resulting in a net heat loss can occur for many parameters currently available in the literature. From the transient and sensitivity studies, it is observed that the appropriate selection of collector-type pond's parameters is synchronized by a mutual trade-off between the allowable time and the pond's efficiency.