增强型CO_(2)跨临界冷电联产系统性能分析

Performance Analysis of Combined Cooling and Power Production with Enhanced CO_(2) Transcritical Cycle System

二氧化碳(CO_(2))作为一种天然制冷剂,越来越受到人们的重视,但CO_(2)制冷循环效率低,限制了其应用范围。为提高CO_(2)制冷循环效率,提出了一种增强型CO_(2)跨临界冷电联产系统。该系统以有机朗肯循环(ORC)回收CO_(2)跨临界循环的部分冷凝热,将其转换成电能,达到提高系统COP的目的。在不同蒸发温度、CO_(2)冷凝压力和CO_(2)过热度条件下,分别对比分析了增强型CO_(2)跨临界循环和传统CO_(2)跨临界循环COP变化。结果表明:增强型CO_(2)跨临界循环可以有效提高系统COP,在分析范围内,最大提高率为22%。此外,分析了ORC循环部分使用6种不同有机工质条件下系统COP变化,结果表明:采用R227ea时,系统整体COP值较高。

As a natural refrigerant, carbon dioxide(CO_(2)) has attracted more and more attention. However, the low efficiency of CO_(2) refrigeration cycle limits its application. An enhanced transcritical CO_(2) combined cooling and power production system is proposed. In the system, the organic Rankine cycle(ORC) is used to recover part of the condensation heat of the CO_(2) transcritical cycle and convert to electricity to improve the system COP. The COP of enhanced and traditional CO_(2) transcritical cycle is analyzed under different evaporation temperature, CO_(2) condensation pressure and CO_(2) superheat, respectively. The results show that the enhanced transcritical system could effectively improve the system COP, and the maximum increase ratio is 13.5% within the analysis range. In addition, the study is performed with six different organic working fluids in ORC sub-cycle. The results indicate that R227 ea was better in improving the COP of the overall system.