Cooling tower-assisted ground source heat pump (GSHP) systems have been widely used in the regions where both cooling and heating are required in recent years. However, the issue of system design and management is still under discussion. The ratio of heat removed by cooling tower to the absorbed by the ground would influence the operation performance of hybrid system. This study developed a method to predict the system comprehensive coefficient of performance (SCOP) of hybrid system to optimize system structure and operation. Taking a cooling tower-assisted GSHP in a residential district in a hot summer and cold winter region as an example, a multivariate nonlinear regression prediction model for SCOP was derived based on the data recorded from May to September 2021 by the Building Energy Management System (BEMS) and the simulation results using TRNSYS software. Outdoor dry bulb, wet bulb temperatures, soil temperature, and auxiliary cooling ratio (ACR) are involved in the model. Based on model prediction and system simulation, the ACR of cooling tower-chiller unit should take 0.7 of the accumulated cooling load, considering the SCOP in summer and sustainability for long-term. An operation strategy has been proposed, prioritizing the operation of cooling tower-chiller and controlling the temperature difference between supply and return chilled water within 6℃. The average SCOP of the existing hybrid system can reach 5.56, and the soil temperature rise is within 4℃ over 15 years. The model can predict the variation of average SCOP with ACR during the cooling season in different regions. The calculation results serve as reference for designing and operating hybrid ground source heat pump (HGSHP) systems, ensuring system sustainability while achieving optimal SCOP.

中文翻译：

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冷却塔辅助地源热泵系统性能的多元非线性回归预测模型


近年来，冷却塔辅助地源热泵 （GSHP） 系统已广泛应用于需要制冷和供暖的地区。然而，系统设计和管理的问题仍在讨论中。冷却塔带走的热量与地面吸收的热量之比会影响混合动力系统的运行性能。本研究开发了一种预测混合动力系统系统综合性能系数 （SCOP） 的方法，以优化系统结构和运行。以夏热冬寒地区住宅小区的冷却塔辅助 GSHP 为例，基于建筑能源管理系统 （BEMS） 2021 年 5 月至 9 月记录的数据以及使用 TRNSYS 软件的仿真结果，推导出了 SCOP 的多元非线性回归预测模型。该模型涉及室外干球温度、湿球温度、土壤温度和辅助冷却比 （ACR）。基于模型预测和系统仿真，考虑到夏季的 SCOP 和长期的可持续性，冷却塔-冷水机组的 ACR 应占累积冷却负荷的 0.7 倍。已经提出了一种运行策略，优先考虑冷却塔-冷水机的运行，并将冷却水的供应和返回之间的温差控制在 6°C 以内。现有杂交系统的平均 SCOP 可达 5.56,15 年土壤温度上升在 4°C 以内。该模型可以预测不同地区降温季节平均 SCOP 与 ACR 的变化。计算结果可作为设计和运营混合地源热泵 （HGSHP） 系统的参考，确保系统可持续性，同时实现最佳 SCOP。