TY - JOUR
TI - Numerical investigation on free cooling performance of ground-source heat pump in a solar greenhouse
AU - Hou Zhao
AU - Hu Yuqiu
AU - Liu Xiaojie
AU - Wang Jianhua
AU - Yang Mei
AU - Fan Jun
JN - Thermal Science
PY - 2023
VL - 27
IS - 6
SP - 4719
EP - 4732
PT - Article
AB - This paper presents the numerical study of a ground source heat pump with borehole free cooling in a solar greenhouse. The system is mainly composed of a solar greenhouse with a water-water heat pump, a ground heat exchanger, and several pipes for free cooling. Thermal performances of ground source heat pump with and without borehole free cooling are investigated. The cooling time of the solar greenhouse is divided into transitional seasons (May and September) and summer seasons (from June to August). The mixed mode, including the free cooling mode and the ground source heat pump cooling mode, runs in summer seasons. During the entire transition seasons, the free cooling mode consumes 33.6% of the electricity in the ground source heat pump cooling mode and the soil thermal storage in free cooling mode is 76.3% of that in ground source heat pump cooling mode. Throughout the summer seasons, the power consumption of the mixed mode is 4.3% lower than that of the ground source heat pump cooling mode, and mixed mode soil thermal storage is 19.5% lower than that of ground source heat pump cooling mode. The results indicate that borehole free cooling system has better energy-saving performance during whole cooling period. In addition, a borehole free cooling system can also reduce the thermal imbalance in the soil.