Determination of Thermal-Degradation Rates of Some Candidate Rankine-Cycle Organic Working Fluids for Conversion of Industrial Waste Heat Into Power

Serious concerns over the long-term thermal stability of organic working fluids and its effect on system performance, reliability, and overall economics have impeded widespread development and deployment of organic Rankine-cycle power systems (ORCPSs) for conversion of industrial waste heat into power. Prototype systems built using thermal stability information derived from static capsule tests have often operated less than satisfactorily. This investigation is an attempt by the U.S. Department of Energy (DOE) to alleviate these fears, dissipate the remaining road blocks, and accelerate the further development and deployment of this vital industrial energy-conservation technology. This paper presents some interim results of an experimental investigation undertaken determine degradation rates (as a function of maximum cycle temperature) of four organic working fluids considered potential candidates for use in a Rankine-cycle power-conversion system. The four fluids under investigation are Fluorinol 85, 2methylpyridine/water, toluene, and Freon R-113