A turbomachine expander engineered at Purdue University optimizes energy efficiency in heating and cooling systems by recovering energy wasted in vapor-compression heat pump cycles. The energy-conserving system The turbomachine expander offers an efficient and safe strategy for heating and cooling. Source: Purdue Universitycan be deployed in most commercial, residential and vehicular applications.

The researchers used a split-system heat pump to compare the performance and control capabilities of a variable nozzle and a fixed nozzle with phase separation combined with evaporator bypass flow metering. Operation with a variable nozzle option reduced expander isentropic efficiency relative to the fixed nozzle design. Evaporator bypass control increased system coefficient of performance (COP) by 2.3% with an expander overall isentropic efficiency of 18.8%. Greater COP gains were realized when the heat pump was operated in cooling versus heating mode.

The researchers are looking for partners to continue developing the expander and are in the process of patenting the technology.