Abstract

VON BACKSTROM, T.W.  and  GANNON, A.J.. The solar chimney air standard thermodynamic cycle. R&D j. (Matieland, Online) [online]. 2000, vol.16, pp.16-24. ISSN 2309-8988.

The paper presents an air standard thermodynamic analysis for the solar chimney cycle. A solar chimney is a power plant in which air, heated under a glass-decked solar collector, escapes through a power generating turbine at the base of a chimney. Simple equations were derived for the cycle efficiency, power per unit mass flow and available turbine pressure drop, assuming ideal air as process gas and ideal reversible processes. The main conclusions were the following: the cycle efficiency is directly proportional to the chimney height; unlike the gas turbine cycle, there is no optimal pressure ratio (chimney height) for maximum specific power; the power per unit mass flow developed by the plant is directly proportional to the cycle efficiency and the temperature rise in the solar collector; the pressure drop across the turbine is proportional to the chimney height and the collector temperature rise. A design condition where the chimney exit temperature equals the collector inlet temperature was also proposed for initial calculations. The specific power of the plant is then approximately proportional to the square of the cycle efficiency. The analysis enables one to do initial sizing of a plant for a given required power.

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