APPLICATION OF REFRIGERANT WORKING FLUIDS FOR MOBILE ORGANIC RANKINE CYCLE SYSTEMS

asme-orc2015 Tracking Number 41

Cummins Inc. has been a leading developer of ORC systems for application to heavy-duty, on-highway trucks in the United States for several years. Cummins has passed through several generations of ORC system architecture and has fielded several on-highway vehicles equipped with ORC systems as a part of research conducted in partnership with the United States Department of Energy. Throughout this development, Cummins has carefully evaluated potential working fluids for its ORC systems and has remained committed to using safe and environmentally friendly refrigerants such as R245fa and its recently introduced ultra-low GWP replacements. Integration of Organic Rankine Cycle (ORC) systems into heavy duty, on-highway vehicles requires consideration of a significant number of factors, not the least of which is the choice of working fluid. The selection of fluid is primarily driven by potential performance considering the application at hand, potential environmental and health effects of the fluid, safety, availability, serviceability, etc. Given the working fluid, selection of various system components and optimization of system architecture may be made. This paper will present a brief review of Cummins’ ORC history and discuss background leading to Cummins Inc.’s selection of and adherence to refrigerant working fluids for mobile application. Details of technology that allow refrigerant’s safe and effective use will also be discussed. A performance comparison between R245fa, ultra-low GWP replacements, and ethanol will be presented and an architecture comparison between refrigerant and ethanol systems will be provided. Options and considerations for further development and commercialization of the technology will also be briefly discussed.