Performance comparison and working fluid analysis of subcritical and transcritical dual-loop organic Rankine cycle (DORC) used in engine waste heat recovery
Performance comparison and working fluid analysis of subcritical and transcritical dual-loop organic Rankine cycle (DORC) used in engine waste heat recovery
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DOI：
10.1016/j.enconman.2013.04.037
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发表时间：
2013-10
影响因子：
10.4
通讯作者：
G. Shu;Lina Liu;H. Tian;Haiqiao Wei;Xiaofei Xu
中科院分区：
文献类型：
--
作者：
G. Shu;Lina Liu;H. Tian;Haiqiao Wei;Xiaofei Xu
提出了一种由高温循环和低温循环组成的新型双回路有机朗肯循环（DORC），用于回收发动机排气和冷却液的余热以及高温循环的余热。采用两种不同的系统。根据LT循环采用的循环模式，系统可定义为亚临界-亚临界（sub-sub）DORC或亚临界-跨临界（sub-transic）DORC。选择R125、R143 a和R218作为sub-trans-DORC低温循环的候选工质，R124、R134 a、R245 fa、R600、R600 a和R1234 yf作为sub-sub DORC低温循环的候选工质。选择净输出功率和火用效率作为目标函数。结果表明，以R143 a为工质的次transDORC系统性能最好，其净输出功率和火用效率分别为39.91 kW和48.42%。高温循环的冷凝温度越低，越有利于性能的优化。蒸发器EHT、冷凝器CLT和两台汽轮机（THT和TLT）的不可逆性是前四位的优化目标。对于基于R143 a的次变速器DORC，系统在100%运行负荷下性能最佳。
In this paper, a new dual-loop organic Rankine cycle (DORC) consisting of a high-temperature (HT) cycle and a low-temperature (LT) cycle is proposed to recover the waste heat of the exhaust and the engine coolant and the residual heat of the HT cycle. Two different systems are adopted. According to the cycle mode adopted in the LT cycle, the system can be defined as subcritical–subcritical (sub–sub) DORC or subcritical–transcritical (sub–trans) DORC. R125, R143a and R218 are chosen as the candidate working fluids in the LT cycle of the sub–trans DORC, while R124, R134a, R245fa, R600, R600a and R1234yf are the candidates of the sub–sub DORC. Net output power and exergy efficiency are selected as the objective functions. Results show that R143a-based sub–trans DORC system performs the best and the net output power and the exergy efficiency are 39.91 kW and 48.42%, respectively. Small condensation temperature of the HT cycle is advantageous for the performance optimization. Irreversibilities of evaporator EHT, condenser CLTand the two turbines (THTand TLT) are the top four, which are the optimization objectives. For R143a-based sub–trans DORC, system performs best with 100% operating load.