Choi, Jongmin; Kang, Byun; Cho, Honghyun - In: Renewable Energy 71 (2014) C, pp. 414-424
Solar heat and geothermal energy are widely used renewable energy which is one of important issue for future. Besides, R744 as environmental friendly refrigerant has advantage to apply into heat pump system. In this study, the performance the R22 and R744 solar-geothermal hybrid heat pumps was...