Development of an ORC for High Temperature Waste Heat Recovery Utilizing Scroll Expanders

摘要

An organic Rankine cycle (ORC) test setup has been constructed to investigate high-temperature waste heat recovery from a stationary internal combustion engine. In particular, an experimental study of a subcritical ORC architecture working with a high temperature heat source is performed to evaluate the feasibility of employing an ORC to recover west heat from small-scale internal combustion engines (～10 kW). The affordability of such a system for the given application has a significant impact on the cycle design. The ORC test setup consists of a diaphragm pump, a plate heat exchanger as regenerator, a novel micro-tube evaporator, an air-cooled condenser, a scroll-type expander, and R245fa as working fluid. Focus is given to constraining the high-side temperatures of R245fa to minimize oil breakdown while decreasing exergy destruction in the evaporator. The cycle performance is evaluated for varying thermal inputs, expander pressure ratios and refrigerant superheating values.