Second law analysis of novel working fluid pairs for waste heat recovery by the Kalina cycle

作者：Eller Tim; Heberle Florian; Brueggemann Dieter

来源：Energy, 2017, 119: 188-198.

DOI：10.1016/j.energy.2016.12.081

• Waste heat recovery
• Second law analysis
• Kalina cycle
• Efficiency increase
• Alcohol mixtures
• Organic Rankine cycle

The organic Rankine cycle (ORC) and the Kalina cycle (MC) are potential thermodynamic concepts for decentralized power generation from industrial waste heat at a temperature level below 500 degrees C. The aim of this work is to investigate in detail novel zeotropic mixtures as working fluid for the KC and compare to sub- and supercritical ORC based on second law efficiency. Heat source temperature is varied between 200 degrees C and 400 degrees C. The results show that second law efficiency of MC can be increased by applying alcohol/alcohol mixtures as working fluid instead of ammonia/water mixtures; especially for heat source temperatures above 250 degrees C. Efficiency increase is in the range of 16% and 75%. Despite this efficiency improvements, ORC with zeotropic mixtures in sub- and supercritical operation mode proves to be superior to KC in the examined temperature range. Second law efficiency is up to 13% higher than for KC. A maximum second law efficiency of 59.2% is obtained for supercritical ORC with benzene/toluene 36/64 at 400 degrees C heat source temperature. The higher level of efficiency and the lower complexity of ORC in comparison to MC indicate that ORC with zeotropic mixtures offers the greater potential for waste heat recovery.

• 出版日期2017-1-15