Inverse Optimization of Design Parameters in a Hybrid Solar Pond System With External Heat Addition

Abstract

Abstract External heat supply to solar ponds from various types of solar collectors is a feasible alternative that significantly enhances its performance. In this work, various design parameters in a hybrid solar pond with external heat addition from Evacuated Tube Solar Collector (ETSC) are evaluated using an inverse approach. A forward model based on heat balance equations is solved for various zones of the solar pond to predict temperatures attained by its storage zone under a given climatic condition. Bryant and Colbeck’s relation is used to account for the diminution of the solar radiation as it travels from upper layers of the solar pond to its bottom layers. The relevant differential equations are solved using a Runge-Kutta fourth order scheme. The component of heat addition from ETSC is added to the forward model in the storage zone’s equation. Heat added from ETSC is considered proportional to the fraction of the aperture area to the pond’s base area, the thermal efficiency of ETSC and global solar radiation incident on ETSC. Both the forward model of the solar pond and combined solar pond and ETSC model were validated with previous experimental and numerical studies available in the literature for El Paso, USA, and Melbourne, Australia. An inverse model based on genetic algorithm is proposed for evaluating the set of geometrical parameters of ETSC and solar pond in order to derive a required performance from the combined solar pond-ETSC system.