Abstract

With a raising concern about climate change and global warming, various environmental regulations such as Kigali Amendment and EU Directive 517/2014 have already set the target to gradually phase out R134a and R123 refrigerants. In the current study, both the medium-pressure refrigerants (R134a and its alternatives R513A and R1234ze(E)) and low-pressure refrigerants (R123 and its alternatives R514A and R1233zd(E)) have been theoretically investigated for multistage chiller systems with a fixed cooling capacity. Compared with a single-stage chiller, a multistage chiller gives a \(\sim 4\)%–8% COP enhancement for medium-pressure refrigerants and \(\sim 4\)%–6% COP increase for low pressure refrigerants. Multistage systems can help to downsize the evaporator and provide more than 5% lifetime emission reductions. A two-stage chiller system is more preferable than the others for its high operating energy saving potential with limited additional component cost increase. In addition, R134a exhibits a better heat transfer performance than its candidates, while R123 exhibits a reverse behavior. R513A can exhibit a \(\sim 9\)% emission reduction as compared with R134a, and R1234ze(E) can provide a \(\sim 18\)% emission drop benefit as compared with R134a. R513A and R134a have a close compressor impeller diameter, and a similar trend can also be exhibited between R514A and R123. Accordingly, R513A is more preferred to replace R134a, and R514A to replace R123 for drop-in considerations due to their close compressor size, close COP, and reduced lifetime emissions. With approaching more strict refrigerant regulations and laws in the future, R1234ze(E) can be the ultimate option to replace R134a.

中文翻译：

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不同低全球变暖潜能值制冷剂的多级离心冷水机组性能指标评估

摘要

随着对气候变化和全球变暖的日益关注，基加利修正案和欧盟指令 517/2014 等各种环境法规已经设定了逐步淘汰 R134a 和 R123 制冷剂的目标。在目前的研究中，中压制冷剂（R134a 及其替代品 R513A 和 R1234ze(E)）和低压制冷剂（R123 及其替代品 R514A 和 R1233zd(E)）均已针对具有固定制冷量。与单级制冷机相比，多级制冷机 对中压制冷剂和\(\sim 4\)的 COP 提高了\(\sim 4\) %–8%低压制冷剂的 COP 增加 %–6%。多级系统有助于缩小蒸发器的尺寸并提供超过 5% 的寿命排放减少。两级冷水机组比其他冷水机组更可取，因为它具有较高的运行节能潜力，且附加组件成本增加有限。此外，R134a 表现出比其候选者更好的传热性能，而 R123 表现出相反的行为。与 R134a 相比， R513A 可以表现出 \(\sim 9\) % 的排放减少，而 R1234ze(E) 可以提供 \(\sim 18\)与 R134a 相比，排放下降收益百分比。R513A和R134a的压气机叶轮直径接近，R514A和R123之间也可以表现出类似的趋势。因此，R513A 更优选替代 R134a，而 R514A 更优选替代 R123，因为它们的压缩机尺寸接近、COP 接近且寿命排放减少。随着未来制冷剂法规和法律越来越严格，R1234ze(E) 可以成为替代 R134a 的最终选择。