Thermodynamic performance of a modified −150 °C refrigeration system coupled with Linde-Hampson and three-stage auto-cascade using low-GWP refrigerants
Thermodynamic performance of a modified −150 °C refrigeration system coupled with Linde-Hampson and three-stage auto-cascade using low-GWP refrigerants
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DOI：
10.1016/j.enconman.2021.114093
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发表时间：
2021-05
影响因子：
10.4
通讯作者：
Yanbin Qin;Nanxi Li;Hua Zhang;Baolin Liu
中科院分区：
文献类型：
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作者：
Yanbin Qin;Nanxi Li;Hua Zhang;Baolin Liu
本研究提出了一种改进的蒸汽压缩制冷循环，结合Linde-Hampson制冷系统和三级自级联制冷系统（LHR-ACR），使用低gwp混合物作为制冷剂。建立了基于能量和火用方法的数学模型，对不同成分和蒸汽质量下的系统性能进行了评价，包括制冷量、性能系数（COP）、蒸发温度、火用破坏和效率。对换热器进行了夹点分析。结果表明，系统性能的提高伴随着蒸发温度和压缩机排气温度的升高。因此，多目标优化方案是LHR-ACR系统设计的最全面、最优方案。结果进一步表明，当R1234yf/R32组分、R170/R14/R50组分和蒸汽质量分别为0.54/0.46、0.52/0.22/0.26和0.45时，LHR-ACR系统具有较好的热力性能，在- 150℃时火用效率为15.18%，COP为0.1438。火用破坏最大的部件是梯级冷凝器- iii，其次是ACR风冷冷凝器和ACR压缩机，后续可以对其进行优化工作。本文所提出的新方法和所得结果对超低温制冷机的优化设计和应用具有一定的参考价值。
This study presents a modified vapor compression refrigeration cycle coupled with a Linde-Hampson refrigeration system and a three-stage auto-cascade refrigeration system (LHR-ACR) using low-GWP mixtures as the refrigerant. A mathematical model based on the energy and exergy methods was developed to evaluate the system performances at varied compositions and vapor qualities, including the cooling capacity, coefficient of performance (COP), evaporation temperature, exergy destruction and efficiency. The pinch point analysis for the heat exchangers was also carried out. The results show that the improvement of the system performance is accompanied by the rise of the evaporation temperature and the compressor discharge temperature. Thus, a multi-objective optimization scheme is the most comprehensive and optimum for the design of an LHR-ACR system. Results further indicate that the LHR-ACR system has a better thermodynamic performance with exergy efficiency of 15.18% and COP of 0.1438 at −150 °C when the R1234yf/R32 composition, R170/R14/R50 composition and vapor quality are 0.54/0.46, 0.52/0.22/0.26 and 0.45, respectively. The component that shows the largest exergy destruction is the cascade condenser-III, followed by the ACR air-cooled condenser and ACR compressor, on which future optimization work can be carried out. The proposed new approach and the results obtained in this paper will be valuable for the optimum design and application of the refrigerator at ultra-low temperature levels.