| Title |
Thermal Performance Analysis of a Hybrid Solar-Assisted GSHP Heating System in a Greenhouse Using TRNSYS |
| Authors |
Hee Won Lim ; Wang Je Lee ; U Cheul Shin |
| DOI |
https://doi.org/10.6110/KJACR.2023.35.6.286 |
| Keywords |
애플망고; 보어홀 열저장; 온실; 지열히트펌프; 태양열시스템 Apple mango; Borehole thermal energy storage; Greenhouse; Ground source heat pump; Soar heating system |
| Abstract |
In this study, we proposed a hybrid solar-assisted GSHP heating system with underground seasonal thermal energy storage and evaluated the thermal performance and dynamic operating characteristics of the greenhouse for apple mango with a total area of 2,300 m2. The heating load in winter was supplied by the solar thermal system, and the remaining load was met by the closed-loop vertical GSHP System. The surplus solar heat in the non-winter season was stored in underground storage, which compensated for the winter ground temperature drop. The system was mainly composed of four parts: an evacuated tube solar collector with a gross area of 380 m2, GSHP with a 210 kW heating capacity, a solar storage tank of 100 m3, and a cylinder-shaped borehole thermal energy storage system with a storage volume of 64,910 m3. TRNSYS 18 was used as the analysis tool, and the main results are summarized as follows. First, the peak heating load and total annual heating load of the greenhouse were 546 kW and 327 MWh, respectively. Second, the annual average collector efficiency was 49.5%, and the total annual useful heat gain was 227.5 MWh. Of this, 100 MWh was directly supplied for greenhouse heating, and the remaining 150 MWh was stored in underground storage. The solar fraction was found to be 30%. Third, the amount of heating supplied by the GSHP was 231.1 MWh, which was 70% of the total heating load. As a result, the renewable energy fraction reached 100%. Fourth, the heat storage efficiency of underground seasonal thermal energy storage by surplus solar heat was 70%. Even though the GSHP operated mainly on heating, the ground temperature did not fall. |