Abstract

Climate change concerns have made the engineering community care more about environmentally friendly working fluids. Currently, the fluid R134a, which has a high global warming potential, is widely used in chiller applications. In this study, several low GWP working fluids, R450A, R513A, R1224yd(Z), and R1234ze(E), are investigated numerically as alternatives to R134a for comparison of their performance under different operating conditions in a centrifugal chiller application. Both the system level performance and component level performance are presented. Increasing the condensing temperature or decreasing the evaporating temperature can lead to a higher compressor power, and thus a lower COP can be obtained. The effect of superheat is trivial for the system level performance. R1224yd(Z) has the lowest value of volumetric capacity, and R513A has a higher value as compared with the baseline. As for retrofit, R1224yd(Z) can only produce \(\sim 20\)% of the baseline cooling capacity. As for the compressor size, the R1224yd(Z) value is more than double as compared with the baseline R134a one, and R513A has a compressor size closest to that of the baseline R134a. R450A and R1234z(E) have a slightly higher value in terms of the compressor size. In general, R513A is the best candidate as an R134a alternative.

中文翻译：

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R134a 低 GWP 替代品在离心式冷水机组中的性能研究

摘要

对气候变化的担忧使工程界更加关注环保工作液。目前，具有高全球变暖潜势的流体 R134a 广泛用于冷却器应用。在这项研究中，对几种低 GWP 工作流体 R450A、R513A、R1224yd(Z) 和 R1234ze(E) 进行了数值研究，作为 R134a 的替代品，以比较它们在离心式冷水机应用中不同操作条件下的性能。介绍了系统级性能和组件级性能。提高冷凝温度或降低蒸发温度可以导致更高的压缩机功率，因此可以获得更低的COP。过热对系统级性能的影响微不足道。R1224yd(Z) 具有最低的容积容量值，与基线相比，R513A 具有更高的值。至于改造，R1224yd(Z)只能生产\(\sim 20\) % 基线冷却能力。至于压缩机尺寸，R1224yd(Z) 值是基准 R134a 的两倍多，而 R513A 的压缩机尺寸与基准 R134a 的压缩机尺寸最接近。R450A 和 R1234z(E) 在压缩机尺寸方面的值略高。一般来说，R513A 是作为 R134a 替代品的最佳候选者。