Critical temperature criterion for selection of working fluids for subcritical pressure Organic Rankine cycles
Critical temperature criterion for selection of working fluids for subcritical pressure Organic Rankine cycles
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DOI：
10.1016/j.energy.2014.07.038
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发表时间：
2014-09
期刊：
影响因子：
9
通讯作者：
Jinliang Xu;Chao Yu
中科院分区：
文献类型：
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作者：
Jinliang Xu;Chao Yu
提出了一种将热源与有机朗肯循环（ORCs）耦合的方法。综合平均温差ΔTave量化了蒸发器内的热匹配。ΔTavedecreases随着临界温度（Tc）的增加。当烟气入口温度为t0时，烟气入口温度为t0→0.5 × （t0，烟气入口温度为- T5），称为最优温差，此时热效率最大。当流体为100吨/吨/吨/吨时，ORC性能与最佳工况偏差较小。热效率与临界温度密切相关。除ttc外，ORC热效率随其他流体物理性质随机分布。因此，就热效率而言，临界温度可以作为流体选择的唯一标准。推荐使用Tgas（−20 - 30k,Tgas, + 100k）范围内的有机流体。通过筛选57种流体，建议热源温度范围为（100-300°C）的特定流体。对于低热源温度的orc，有更多的流体可用。有限的流体可用于高温热源应用。由于II区的流体膨胀，一些流体如R245fa可以在很宽的热源温度范围内使用。
A method was proposed to couple the heat source with ORCs (Organic Rankine Cycles). The integrated-average temperature difference, ΔTave, quantifies the thermal match in the evaporator. ΔTavedecreases with increase in critical temperatures (Tc). The fluid withTcapproachingTgas,in(flue gas inlet temperature) can have ΔTave→ 0.5 × (Tgas,out−T5), which is called the optimal temperature difference, at which the thermal efficiency is maximum. The ORC performance with fluids ofTc>Tgas,inhas less deviation from the optimal condition. Thermal efficiencies are well correlated with critical temperatures. The ORC thermal efficiencies are randomly distributed against other fluid physical properties exceptTc. Thus, the critical temperature can be the sole criterion for the fluid selection, as far as the thermal efficiency is concerned. The organic fluids withTcin the range of (Tgas,in− 20–30 K,Tgas,in+ 100 K) are recommended. Specific fluids are recommended for heat source temperature in the range of (100–300 °C) by screening 57 fluids. More fluids are available for ORCs with low heat source temperatures. Limited fluids are available for high temperature heat source applications. Due to the expanded fluids in region II, some fluids such as R245fa can be used over a wide heat source temperature range.