山岭隧道衬砌换热器地源热泵能效的影响因素研究

Influencing factors of energy efficiency for heat pump coupled with mountain tunnel lining ground heat exchangers

为了分析山区环境下的隧道衬砌换热器地源热泵能效,建立了隧道衬砌换热器的瞬态传热三维数值计算模型。分析了制冷工况下隧道衬砌换热器地源热泵的运行能效。分析结果表明:地源热泵能效比随着风速的增大先减小后增大;随着围岩导热性的增强而增大,但增大速率逐渐降低;随着围岩初始地温的升高呈线性减小。上述因素敏感性分析结果表明,风速对隧道衬砌换热器地源热泵能效比的影响程度最小,初始地温最大。随着管长的增加,初始地温对地源热泵能效比影响权重逐渐增大,风速和围岩导热系数的影响权重逐渐减小。

To investigate the energy efficiency of the heat pump coupled with tunnel lining ground heat exchangers(GHEs)in a mountain environment,a 3D numerical model is developed to simulate the transient heat transfer of the tunnel lining GHEs.The energy efficiency of the heat pump coupled with tunnel lining GHEs in the cooling mode is evaluated.The results demonstrate that the EER of the ground-source heat pump decreases and then increases with the increase of wind speed.The EER increases with the increase of thermal conductivities of the surrounding rocks,whereas the growth rate decreases gradually.The EER decreases lineally with the increase of initial ground temperature.The results of the sensitivity analysis show that the wind speed has the least influence and the initial ground temperature has the greatest influence on the EER of the ground-source heat pump coupled with tunnel lining GHEs.As the absorber pipe length increases,the weight of the initial ground temperature on the EER increases,while the weights of the wind speed and thermal conductivity of the surrounding rock gradually decrease.