Feasibility study of a hybrid renewable energy system with geothermal and solar heat sources for residential buildings in South Korea

This study investigates the economic feasibility of a hybrid renewable energy system (HRES) that uses geothermal and solar heat sources for water heating, space heating, and space cooling in a residential building in Korea. A small-scale HRES consists of a geothermal heat pump for heating and cooling, solar collectors for hot water, a gas-fired backup boiler, and incidental facilities. To determine whether the HRES will produce any economic benefits for homeowners, an economic analysis is conducted to compare the HRES with conventional methods of space heating and cooling in Korea. The payback period of a small-scale HRES is predicted as a maximum of 9 yrs by life cycle costing based on a performance index compared with conventional systems. However, the payback period of large-scale HRES above 400 RT is 6 yrs to 7 yrs.