36 Distributed Generation and Alternative Energy Journal Energy From Salt Lakes: A Primer on Salt Gradient (Solar) Ponds

Abstract

Any lake absorbs heat from the sun. Normally, heat is lost aswarmed water rises to the surface and cools by evaporation. But wateris a VERY poor conductor of heat and if this circulation can be stopped,the heat can be trapped in the bottom of the lake. A salt lake, (ideallyabout 3m deep), managed so that the water on top is of relatively lowsalinity (density ~1.0g/cc) and the water on the bottom is of very highsalinity (density ~1.2g/cc), will not circulate to release heat because thewater on the bottom is so heavy with salt it cannot rise—even at quitehigh temperatures. The deeper water gets very hot—in the right circum-stances (the record is 114°C)—70°C degrees is common in even temperateclimates. In Southern Australia 50°C is easily achievable—even in winter.Run like this, such ponds are called ‘Salt Gradient Solar Ponds’ orjust ‘Solar Ponds’.

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Identifiers

DOI

10.13052/dgaej2156-3306.2633

Journal

Distributed Generation & Alternative Energy Journal

Year

2011