温室调温系统中埋管换热器传热模型构建与分析OACHSSCD

Closed-loop ground heat exchangers(GHEs),also known as buried pipe heat exchangers,are widely applied in greenhouse climate control.However,the heat transfer models of GHEs are often complex and consider only a limited number of influencing factors.In this study,a heat transfer model for GHEs was developed using the shape factor method,and the heat transfer characteristics of the exchangers were analyzed.The results show that the maximum relative error of model-calculated outlet water temperature and experimental measurements is 5.14％.A pipe-laying area of 10 m × 5 m,pipe arrangement,soil type,burial depth,inlet water temperature,and water flow rate significantly influence the heat exchange capacity,whereas the diameter and material type of the pipe exhibit minimal effects.Considering both heat transfer performance and operational costs,the optimized configuration and operating parameters are as follows:polyethylene(PE)pipes with 16 or 20 mm outer diameter laid along the greenhouse length,burial depth of 0.4 m,pipe spacing of 0.3 m,inlet water temperature of 30-35℃,and water mass flow rate of 0.03-0.04 kg/s.