Selection of Working Fluids for the Organic Rankine Cycle

The subject of selecting working fluid and process operating conditions for the waste heat binary power cycle is addressed herein. The waste heat temperature range from 300 F to 500 F was considered the economic resource range. The available literature on selection of a working fluid for the relatively low level binary power cycle has concentrated on the paraffinic and halogenated hydrocarbons. In order to examine a wider variety of potential working fluids, including mixtures tailored to suit the conditions of the power cycle, a fluid screening procedure was developed. The effect of mixture working fluids on Rankine cycle performance is compared with the increased performance that can be achieved with the multiple or cascade boiler configurations. Preliminary studies indicate that mixtures may provide a net power increase of about 20%