The solar pond as a possible source of solar energy — First results of experiments on a Northern Italian farm

Abstract

The report is divided into two parts. The first deals with operating principles and the main technologies of solar pond construction on the basis of data obtained from the literature. The second part covers the experience gathered in 2 years of experimental work on a small solar pond (20 m 2, 0.8 m deep) installed at the experimental farm of the University of Milan. A saline gradient was obtained by diffusion of salt (NaCl) from the pond bottom. The maximum temperatures achieved were 55–60°C and the mean energy harnessing efficiency was 10–20%. The major problems encountered concerned the need to maintain the transparency and efficiency of the saline gradient layer at optimum conditions. This study is part of a research project for the assessment of the practicability of solar pond technologies under Northern Italian ambient conditions. The small pond is a preliminary to larger facilities (140–160 m 2) to be built into an existing farm.