연구홍보포털

논문 초록 (Abstract)

There is increasing demand for domestic and industrial refrigeration, space heating and air conditioning. Heat pump systems oer economical alternativ es for recovering heat from dierent sourc es for usein these applications. As a renewable energy technology f or sustainable environment,the heat pump's high e켧iency and low environmental impact have already drawn a fair amount of attentio n all over the world. Some of these domestic and industrial applications require very low evaporating temperatures and very high condensing te mperatures which induce high compressor pressure ratios beyond the pract ical range for single-stage heat pump cycles. These high pressure rat ios also produce low coe켧ient of performance (COP) values and expose the compressor to high discharge temperature, low volumetric e켧iency and damage. However, this challenge can be overcome by adopting two-stage heat pump cycles. In this pape r, recent works on two-stage heat pump systems for various applicati ons are reviewed. They include two-stage cycle with intercool ing, two-stage cycle with refrigerant injection and two-stage cascade c ycle. Research and innovative designs of systems that make use of these two-stage cycles have been able to get heat pumps to handle applicat ions with lower