There is an increased focus on the amount of refrigerant used in the HVAC&R systems due to the ongoing phase-down of high GWP refrigerants. In the current work, charge optimization is conducted with a variable speed compressor in an R410A chiller having a nominal cooling capacity of 8 kW, which is installed with a condenser, receiver and dedicated subcooler. This study also provides for the first time insights into how a receiver and a dedicated subcooler can be used to not only obtain optimum subcooling but also account for any potential refrigerant leaks by holding additional charge in the receiver. Results indicate that an ideal charge optimization curve can be achieved by sizing the condenser and subcooler to ensure only the optimum subcooling happens in the subcooler. The impact of dedicated subcooler and condenser sizing on charge optimization as well as the system, and seasonal performance is also studied. This analysis helps in understanding how these components should be sized and when the diminishing returns occur from oversizing. This work also shows that when the system is operating with enough refrigerant to fill the receiver with saturated liquid refrigerant, using a dedicated subcooler decouples the cooling capacity increment from power consumption increase typically observed with increasing subcooling. Results show that for the current system investigated increasing the dedicated subcooler area beyond 8 % of the total available heat rejection area will not yield any additional seasonal performance improvement.

中文翻译：

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带有专用过冷器的 R410A 冷水机组中热交换器尺寸对充注优化影响的实验分析

由于高 GWP 制冷剂的持续淘汰，人们越来越关注 HVAC&R 系统中制冷剂的使用量。在当前的工作中，在标称冷却能力为8 kW的R410A冷水机组中使用变速压缩机进行充注优化，该冷水机组安装有冷凝器、接收器和专用过冷器。这项研究还首次深入了解如何使用接收器和专用过冷器不仅获得最佳过冷，而且还通过在接收器中保留额外的充量来解决任何潜在的制冷剂泄漏问题。结果表明，通过调整冷凝器和过冷器的尺寸以确保过冷器中仅发生最佳过冷，可以实现理想的充气优化曲线。还研究了专用过冷器和冷凝器尺寸对充气优化以及系统和季节性性能的影响。此分析有助于了解如何调整这些组件的规模以及何时因规模过大而导致收益递减。这项工作还表明，当系统使用足够的制冷剂运行以用饱和液体制冷剂填充接收器时，使用专用过冷器可以将冷却能力的增量与通常随着过冷度增加而观察到的功耗增加分开。结果表明，对于当前所研究的系统，将专用过冷器面积增加到总可用排热面积的 8% 以上不会产生任何额外的季节性性能改进。