一次泵变流量系统部分负荷特性实验

Experimental study on partial load characteristics of variable primary flow air-conditioning system

搭建了变流量空调系统实验台,对一次泵变流量空调系统在定干管压差控制策略下部分负荷工况的运行特性进行了实验。结果表明:随着负荷率的降低,冷水机组COP先升高后降低,且在60%负荷率时COP最高;水泵综合效率始终降低;冷水机组输入功率与水泵输入功率呈现出不同的变化趋势——水泵输入功率始终降低,而冷水机组输入功率先降低后升高,导致27.2%负荷率下冷水机组和水泵的总输入功率高于45.1%负荷率下的总输入功率;水泵的变频运行不满足相似定律,推导出水泵输入功率与流量的关系方程,得出其输入功率与定压差阻力和机房侧阻力所占比重以及水泵综合效率有关,实验中水泵的输入功率近似与流量的二次幂成正比。

An experiment table of variable flow air conditioning system was set up for studying the operation characteristics of variable primary flow air-conditioning system under partial load conditions with constant differential pressure control strategy. The results show that as the load rate decreases, the COP of the chiller increases first and then decreases, and the highest COP appears at 60% load rate. The integrated efficiency of the pump is always reduced, while the chiller input power and pump input power show different trends—the pump input power is always reduced, and the chiller input power decreases first and then increases, resulting in the total input power of chiller and pump at 27.2% load rate being higher than that at 45.1% load rate. The variable frequency operation of the pump does not satisfy the affinity law. The equation of correlations between pump input power and flow rate is obtained, reasoning out that pump input power is related to the ratio of the constant differential pressure, the resistance of the equipment room and the integrated efficiency of the pump.The input power of the pump in this experiment is approximately proportional to the second power of the flow rate.