冷却塔辅助地源热泵系统的控制策略优化

Control Strategy Optimization on Cooling Tower Assistance to Ground Source Heat Pump System

基于质量和能量守恒原理,采用集总参数法建立了上海某办公建筑的冷却塔辅助地源热泵系统的非稳态数学模型,考虑系统热容在运行中的延迟衰减作用并适当简化了地埋管管群的建模过程,为地源热泵实际工程的系统模拟优化提供参考。以系统COP及年土壤温度变化为优化目标,以不同控制策略下的设定值为优化变量,以非稳态数学模型为控制方程,对不同模式的系统的运行状况进行了模拟,性能分析结果表明:冷却塔与地埋管并联比串联更有利于实现系统冬夏季对土壤的取放热平衡,且对于并联系统,采用2℃温差控制冷却塔启停辅以地埋管2 h间歇运行的控制策略最佳,既能保证系统较高的COP,又能保证土壤的热平衡。

Based on the mass and the energy conservation principles and the lumped parameter method,a set of unstable mathematical model was established for a ground source heat pump system（ GSHPS） aided by cooling tower in an office building in Shanghai. This modeling process of buried pipes is simplified as taking into consideration of the delaying and attenuation effect of the system heat capacity and reference for the simulation and optimization of the actual projects in the ground source heat pump is provided. Taking COP of the system and annual soil temperature variations as the optimization objective,the set value in different control strategies as the optimization variate,system operational states were simulated using the control equation of unstable mathematical model. Results of performance analysis indicate that the way for cooling tower and buried pipes in parallel is more beneficial to achieve the soil heat balance for the system between winter and summar than the way in series,and the control strategy of setting the temperature difference to be 2 ℃ to control the operation of cooling tower assisted with 2-hour intermittent operation of buried pipes is the best solution for the parallel system,which can make the system achieve high COP value as well as maintain heat balance of the soil.