Compact Turbo-Rankine Bottoming Cycle

Electric generators for military and civilian applications produce large amounts of waste heat. This heat can produce additional electric power via a bottoming cycle. The resulting power would enable the use of more electronic devices and/or reduce fuel consumption and its associated costs and logistical burdens. Large power plants frequently use bottoming cycles, but smaller generators rarely include them. The primary reason is that the bottoming systems would be relatively large and inefficient for the low heat source temperatures and low power capacities associated with mobile generators. Fundamental thermodynamic limits, scaling penalties, and manufacturing constraints are the greatest limitations. Fortunately, Creare has focused intense effort on the development of miniature turbomachines, heat exchangers, and thermodynamic systems for nearly 30 years, making us an ideal candidate for this project. We propose to develop a 10 kWe turbo-Rankine system that can be used as either a bottoming cycle or a standalone generator. The resulting system will have extremely high power density and efficiency. We will perform design analyses, conduct trade studies, develop preliminary designs for the components and system, and assess producibility and life-cycle costs during Phase I; followed by fabrication and testing of a breadboard turbo-Rankine generator during Phase II.