CAJ | 학술논문

跨临界有机朗肯-蒸气压缩制冷系统可以使工质与地热流体更好地匹配，减小系统的不可逆性。本文建立该系统的热力学模型，利用EES软件编程，分别对以R143a、R218及R125为工质的系统进行性能分析。计算结果表明，相比R218及R125，以R143a为工质的系统的性能是最佳的。为了避免膨胀机内产生湿蒸气，对于一定的膨胀机进口温度，膨胀机入口存在一个极限压力，并且存在一个最优压力使得系统的性能最佳。地热流体温度的升高可以提高系统的制冷能力，但系统的性能系数则随之先增大后减小；随着地热流体干度的增加，地热流体释放的潜热会大大增加系统的制冷量，而系统的性能系数保持不变。冷凝温度及蒸发温度对系统性能有着重要影响，其中冷凝温度的影响更为明显。以 R143a 为工质的跨临界有机朗肯-蒸气压缩制冷系统的最佳性能优于以 R245fa 为工质的亚临界有机朗肯-蒸气压缩制冷系统的最佳性能。
과림계유궤랑긍-증기압축제랭계통가이사공질여지열류체경호지필배，감소계통적불가역성。본문건립해계통적열역학모형，이용EES연건편정，분별대이R143a、R218급R125위공질적계통진행성능분석。계산결과표명，상비R218급R125，이R143a위공질적계통적성능시최가적。위료피면팽창궤내산생습증기，대우일정적팽창궤진구온도，팽창궤입구존재일개겁한압력，병차존재일개최우압력사득계통적성능최가。지열류체온도적승고가이제고계통적제랭능력，단계통적성능계수칙수지선증대후감소；수착지열류체간도적증가，지열류체석방적잠열회대대증가계통적제랭량，이계통적성능계수보지불변。냉응온도급증발온도대계통성능유착중요영향，기중냉응온도적영향경위명현。이 R143a 위공질적과림계유궤랑긍-증기압축제랭계통적최가성능우우이 R245fa 위공질적아림계유궤랑긍-증기압축제랭계통적최가성능。
The transcritical Organic Rankine-Vapor Compression refrigeration system can make working fluid well match geothermal fluid, benefit for reducing the irreversibility of the system. A thermodynamical model is set up to analyze the performance of the system selecting R143a, R218 and R125 as working fluid respectively. The calculation is conducted by the EES program. The results show that R143a is the most appropriate working fluid for the system compared with R218 and R125. To avoid wet vapor in the expander, the expander inlet has a limited pressure in a constant temperature. Moreover, there exists an optimum pressure for the system performance. A higher geothermal fluid temperature can improve the refrigerating capacity. However, the system performance coefficient may firstly increases and then decreases with geothermal fluid temperature increasing. As the geothermal fluid dryness increases, the higher system refrigerating capacity can be obtained, which results from the release of large amounts of latent heat, while, the system performance coefficient remains unchanged. The condensation and evaporation temperature have great effects on the system performance. Compared with evaporation temperature, condensation temperature has a more significant effect. The optimum performance of transcritical Organic Rankine-Vapor Compression refrigeration system using R143a as working fluid is better than that of subcritical Organic Rankine-Vapor Compression refrigeration system using R245fa as working fluid.