CO2/R170共沸混合制冷剂应用于冷柜系统的热力学性能分析

Thermodynamic performance analysis of CO2/R170 azeotropy refrigerant applied in refrigerated cabinet

基于一套小型冷柜系统建立了热力学模型,将纯CO2制冷剂和CO2/R170共沸混合制冷剂分别应用于该系统,详细计算了系统的性能参数和[火用]效率,并进行了全面的对比。研究结果表明:CO2/R170共沸制冷剂可显著降低排气温度,在所研究的范围内,最高可达16℃;在系统COP及[火用]效率方面,CO2/R170共沸制冷剂存在劣势;随着气冷器出口温度升高,系统的COP及[火用]效率方面的劣势不断减小,而降低排气温度方面的优势在持续增大,且压缩机的压缩比越来越低。因此,将CO2/R170共沸制冷剂应用于冷柜具有很强的可靠性,且更适用于气冷器出口温度较高的系统。

The thermodynamic model based on a small refrigerated cabinet was established in the paper.Pure CO2 and CO2/R170 azeotropic mixture were used in the system as refrigerants.The performances and exergy efficiencies of the two systems were calculated and compared in detail.The results show that the CO2/R170 azeotropic refrigerant could significantly reduce the discharge temperature(up to 16℃ under the studied conditions).In view of COP and exergy efficiency,the CO2/R170 azeotropic refrigerant is inferior compared with the pure CO2.With the increase of gas cooler outlet temperature,the disadvantage of COP and exergy efficiency gradually reduces,while the advantage of discharge temperature continually increases,and the compression ratio of the compressor becomes lower and lower in the meantime.Therefore,the CO2/R170 azeotropic refrigerant can be applied in the refrigerated cabinet with high reliability,and is more suitable for the system with high outlet temperature of gas cooler.