Optimization of waste heat based organic Rankine cycle powered cascaded vapor compression-absorption refrigeration system
Optimization of waste heat based organic Rankine cycle powered cascaded vapor compression-absorption refrigeration system
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DOI：
10.1016/j.enconman.2017.11.045
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发表时间：
2017-12
影响因子：
10.4
通讯作者：
Bhavesh Patel;N. Desai;S. S. Kachhwaha-S.
中科院分区：
文献类型：
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作者：
Bhavesh Patel;N. Desai;S. S. Kachhwaha-S.
本文对基于余热的有机朗肯循环复叠式蒸汽压缩-吸收制冷系统进行了热经济性优化。采用干燥有机工质的有机朗肯循环作为发电循环，为蒸汽压缩制冷系统提供输入。此外，膨胀机出口处的高温有机工质用于提供蒸汽吸收制冷系统的热量需求。本系统实现了高效的低温冷却。然而，初始资本成本和复杂性是目前系统的实际限制。计算了该系统在单独制冷模式和热电联产模式(制冷供热)下的能量效率分别为22.3%和79%。可以注意到，除了蒸汽吸收系统的热能需求之外，可用的额外热量被视为热电联产模式中的过程热。简单回收期和盈亏平衡点(对于基本情况)分别计算为5.26年 年和4.22年 年。利用基于共轭方向法的非线性规划方法，对系统规模和年化成本进行了优化，使系统具有潜在的工业部门吸引力。优化结果表明，与基本情况相比，本系统的年化成本降低了约12%。此外，简单回收期和盈亏平衡点分别降至4.5 年和3.48 年。对现有蒸汽压缩制冷系统与单机蒸汽压缩制冷系统的经济比较研究结果表明，较高的电价和较低的折扣率有利于选择现有的蒸汽压缩制冷系统。
In this paper, the thermo-economic optimization of the waste heat based organic Rankine cycle powered cascaded vapor compression-absorption refrigeration system is presented. Organic Rankine cycle with dry organic working fluid is used as a power generating cycle to provide input to the vapor compression refrigeration system. Moreover, the high temperature organic working fluid at the expander outlet is used to supply thermal need of the vapor absorption refrigeration system. The present system achieves low temperature cooling efficiently. However, initial capital cost and complexity are the practical limitations for the present system. The energetic efficiency of the present system for only cooling mode and cogeneration mode (cooling and heating) are calculated to be 22.3% and 79%, respectively. It may be noted that the extra heat available, apart from the thermal energy requirement of the vapor absorption system, is taken as process heat in the cogeneration mode. The simple payback period and break-even point are calculated (for the base case) to be 5.26 years and 4.22 years, respectively. The system size and annualized cost are optimized, using nonlinear programming based on conjugated directions method, to make the system potentially attractive for the industrial sector. Optimization results reveal that the annualized cost of the present system is decreased by about 12% compared to the base case. Moreover, the simple payback period and break-even point are reduced to 4.50 years and 3.48 years, respectively. The results of comparative economic study, between the present and stand-alone vapor compression refrigeration systems, show that the higher value of electricity price and the lower value of discount rate are favorable for the selection of the present system.