Long-Term Thermal Performance Evaluation of a Solar Heating System of Greenhouse with High Temperature Underground Seasonal Thermal Energy Storage

Hee-Won Lim, Hyun-Seung Lee, Wang-Je Lee, U-Cheul Shin
2021 Journal of the Korean Solar Energy Society  
In this study, we analyzed the long-term feasibility of a solar heating system for a citrus greenhouse to address the financial difficulties facing farms and to reduce greenhouse gas emissions. The solar heating system consisted of an auxiliary boiler, a solar storage tank with a capacity of 100 m 3 and a cylindrical borehole thermal energy system (BTES) with a storage volume of 2,905 m 3 . We installed an evacuated tube collector and flat-plate collector (both with a capacity of 302 m 2 ) to
more » ... asure and compare each solar fraction and thermal storage efficiency. TRNSYS 18 was used as the simulation tool. The annual solar fraction was found to be 83.2%, and the efficiency of thermal storage was 35.7%. In this case, the efficiency of evacuated tube collector and flat-plate collector was 68.7% and 33.2% respectively. This shows that the evacuated tube collector, operating at a relatively high temperature, was more efficient than the flat-plate collector. Despite the high solar fraction, the maximum operating temperature of the solar storage tank was 90° or less, indicating that the tank was less likely to fail due to overheating.
doi:10.7836/kses.2021.41.6.059 fatcat:zytvxfz2mbhipg5beyqkr7exky