Experimental Analysis and Design Improvements on Combined Viper Expansion Work Recovery Turbine and Flow Phase Separation Device Applied in R410A Heat Pump

摘要

In light of recent trends towards energy efficiency and environmental consciousness, the heating, ventilation, air conditioning and refrigeration (HVAC&R) industry has been pushing for technological developments to meet both of these needs. As such, several solutions for harnessing the energy released from refrigerants during the free expansion process of a conventional vapor-compression cycle have been developed to increase overall cycle efficiency. The goal of this research is to investigate the potential impact of installing an energy recovery expander, named Viper Expander, into an R410A heat pump cycle and to increase the efficiency of the expander. To improve the expander design, flow visualization of the two-phase refrigerant leaving the nozzle has been performed. Additionally, a housing redesign that would allow the expander to act as both an expansion work recovery device as well as a flash tank economizer has been proposed and tested as a system solution. Implementing phase separation is intended to have the combined effect of reducing turbine performance losses while also serving as an open economizer to increase overall cycle performance. An experimental investigation of these effects is presented herein, with preliminary experimental results of an expander isentropic efficiency of 18%.