| 摘要: |
| CO2是零ODP、低GWP的天然制冷剂，在冷库制冷系统中应用前景广阔。本文针对用于低温冷库的两级节流中间完全冷却CO2跨临界双级压缩制冷循环（DTCC循环）建立数学模型，通过计算不同工况，分析蒸发温度、压缩机等熵效率、气冷器出口温度、排气压力以及回热循环方式对DTCC循环制冷系数的影响规律；给出DTCC循环的最优排气压力和最佳中间压力的计算式。研究表明：在蒸发温度-30~10 ℃、气冷器出口温度30~45 ℃范围内，DTCC循环的最优排气压力约比相同工况下的单级跨临界制冷循环的最优排气压力低0.3 MPa；低压级排气采用预冷气冷器、在高压级气冷器出口设置回热器均可有效改善DTCC循环的制冷系数。 |
| 关键词: CO2 两级节流中间完全冷却 最优排气压力 最优中间压力 回热循环 |
| DOI： |
| Received:January 19, 2022Revised:February 06, 2022 |
| 基金项目:国家自然科学基金创新群体（51521005）资助项目。 |
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| Performance of CO2 Transcritical Two-stage Compression Refrigeration Cycle with Complete Inter-cooling and Double-stage Throttling |
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Niu Heng1, Xiao Hansong1, Li Wuyan1, Wang Peiqing2, Zhang Xianpeng2, Shi Wenxing1
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| (1.Department of Building Science, Tsinghua University;2.Nanjing Jiuding Environmental Technology Co., Ltd.) |
| Abstract: |
| CO2 is considered to have great application potential in cold storage due to its low global warming potential and zero ozone depletion potential. In this study, a mathematical model was established for a CO2 transcritical two-stage compression refrigeration cycle with complete inter-cooling and double-stage throttling (DTCC cycle) used in cold storage applications. The effects of evaporation temperature, compressor efficiency, gas cooler outlet temperature, discharge pressure, and heat recuperative cycle on the refrigeration coefficient of performance (COP) of the cycle were analyzed atdifferent working conditions. The correlation of optimum discharge pressure and intermediate pressure under a maximum COP was given. When the evaporation temperature te = -30–10 ℃ and the gas cooler outlet temperature tgs = 30–45 ℃, the optimal discharge pressure of the two-stage cycle is approximately 0.3 MPa less than that of the single-stage transcritical refrigeration cycle under the same working conditions. Further analysis showed that the refrigeration coefficient of the DTCC cycle was improved by using anadditional gas cooler for low-pressure discharge gas and by setting arecuperatorat the outlet of the high-pressure gas cooler. |
| Key words: CO2 complete inter-cooling and double-stage throttling optimal discharge pressure optimal intermediate pressure recuperative cycle |
