Optimum Size of Non-Convective Zone of Salt Gradient Solar Pond pp. 57-82
Authors: (Mujahid Husain, Sanjoy Kumar Samdarshi, Shram Sadhna Bombay Trust’s College of Engineering and Technology, Bambhori, Jalgaon, MS, India, and others)
Abstract: Salt gradient solar ponds have history over a century. Kalecsinsky (1902) first reported a pond like phenomenon is Hungarian lakes. Since then researchers have explored various aspects of ponds. Weinberger (1964) first developed analytical solution of pond‘s equations. This made it possible to design ponds for commercial applications. The first finite difference based computer simulation of pond was presented by Hull (1980). It was based up on the iterative approach proposed by Tybout (1966). Tabor has contributed significantly for commercial use of pond especially in Israel. The country has an ambitious plan of meeting complete electricity demand by ponds only by the year 2020 (Amnon Einav 2004). This shows that with the rising energy demand coupled with the severe environmental concerns of traditional fossil fuel energy; solar ponds are emerging as cost effective, environmental friendly viable technology for twenty first century. The thermal performance of SGSP is principally governed by its NCZ size. The present article aims to propose a complete and rational design of NCZ. It proposes analytical approach for selection of NCZ size considering thermal and salt gradient stability aspects. When a SGSP is started, it is filled with saline water in layers. Initially the entire depth of liquid is at ambient temperature. As the time descends, solar radiation penetrates through the liquid content of pond and the pond warms up. The initial warming may take several months depending up on pond‘s vertical dimensions and meteorological conditions. This initial warming is termed as ‗maturation of pond‘ (Husain et al 2003). After initial warm-up pond temperature (temperature of STZ as well as NCZ temperature profile function) does not remain constant, because it is a function of meteorological parameters which themselves are not constant. The meteorological parameters are subjected to cyclic variations. Hence pond temperature also oscillates within certain range. This phase of working of pond is termed as ‗mature phase‘. As such a pond never acquires a true thermal steady state.