Fig。4 (b) shows that schemes CS1 and CS3 had same chiller performance when the chiller load was less than half of the rated cooling capacity。 The COP could increase or reduce when the chiller load is more than 50% of the rated chiller capacity, depending on the working conditions。 The chiller COP could be improved up to 56。3%, which was due to the fact that the circuit 1 was fully loaded with higher compressor efficiency, and the average COP of the two circuits was greater than that of scheme SC1。 However, the COP of scheme CS3 was less than that of scheme CS1 when PLR was great than 0。8, because the two compressors worked with relative higher efficiency in CS1 compared with CS3 under such conditions。 

图4（b）显示方案CS1和CS3有相同的制冷性能当机组负荷低于额定冷却能力的一半。COP可以增加或减少当冷水机组负荷超过额定冷水机组容量的50%，这取决于工作条件。冷水机组COP可提高到56。3%，这是由于电路1是满载高压缩机的效率，和两个电路的平均COP大于方案1。然而，方案CS3的COP低于方案CS1当PLR大于0。8，因为这两个压缩机工作在较高的效率下CS1 CS3等条件比较。来*自-优=尔,论:文+网www.youerw.com

For the scheme CS4, the optimal CLS was implemented, the chiller COP was improved by various degrees up to 56。4% when PLR was greater than 0。25。 It revealed that the optimal CLS could obviously improve the chiller COP for the chillers with multiple refrigeration circuits。 When the optimal CLS and variable condensing temperature control were applied together, the chiller COP could be further improved for all operating conditions up to 66。7% for scheme SC5。 As shown in Fig。 4 (d), the extent of improvement of the chiller COP was much larger when the PLR ranged from 0。5 to 0。75, as under such conditions the optimal load sharing between the two refrigeration circuits could greatly improve the chiller efficiency。 Schemes CS5 and CS1 had same chiller performance when the chiller load was less than 25% of the rated chiller capacity, as only one compressor for the two schemes operated under such conditions。 

该方案实现了CS4，最佳的CLS，冷水机组COP由不同程度达56。4%时，PLR大于0。25的改进。结果表明，最佳CLS可以明显提高冷水机组的制冷机COP与多个制冷电路。当最优CLS和变冷凝温度控制应用，冷水机组COP可用于所有的操作条件下，高达66。7%的SC5进一步改进方案。如图4（d），冷水机组的COP提高的程度大得多的时候，时间范围从0。5到0。75，这样的条件下的最佳负载两制冷电路之间的共享可以大大提高制冷效率下。方案的CS5和CS1具有相同的主机性能当机组负荷低于额定制冷能力的25%，至于两方案在这种情况下只有一个压缩机操作。