Perspectives for Waste Heat Recovery by Means of Organic Fluid Cycles

Abstract

Organic compounds, employed as working fluids for low temperature heat recovery, are shown to exhibit a performance better than that of steam cycles. The potential influence on efficiency and specific work of organic fluid power recovery applied to existing open cycle gas turbine, diesel and gas engines is illustrated on the base of a statistical documentation. The basic characteristics of a typical combined cycle layout are analyzed with respect to fuel economy, air consumption and heat exchange surface requirements. The possibility of improving the performance of closed cycle (helium) gas turbines by means of an organic fluid heat recovery cycle is then examined. The potential benefits deriving from the use of the power turbine of the organic fluid cycle as a direct driver for the compressor of a refrigerating cycle or heat pump employing the same working fluid are discussed. The basic results of a test program aiming to determine the decomposition rates and the corrosion characteristics of some organic working media are presented.