Thermo-economic analysis of a novel hybrid multigeneration system based on an integrated triple effect refrigeration system for production of power and refrigeration

Multigeneration systems provide substantial benefits in terms of improving efficiency and economics as well as environmental benefits. In this study, a multigeneration system is proposed for generating power and triple effect refrigeration at different evaporation temperatures. The system hybridizes a 25 MW recuperative Brayton cycle with an organic Rankine cycle (ORC) and an integrated refrigeration system that combines a branched generator-absorber heat exchange (GAX) absorption refrigeration system with a dual-evaporator cascade carbon dioxide-ammonia compression refrigeration system. The exhaust gas from the Brayton cycle is divided into two streams: one is supplied to the generator of the GAX cycle and the remaining is supplied to the ORC for additional power generation. Results show that additional power generation by ORC increases thermal efficiency from 0.394 to 0.510 and reduces the levelized cost of electricity from $75.5/MWh to $64.4/MWh. The integration of GAX cycle and cascade cycle is beneficial from both thermodynamic and economic viewpoints. Due to their integration, the coefficient of performance of the cascade cycle increases substantially from 2.37 to 4.69. Also, the levelized cost of cooling for the production of triple effect refrigeration decreases from $0.08/ton-hr to $0.059/ton-hr. Environmental analysis shows that the development of multigeneration system can lead to avoiding 24,185 tons of CO2 per year. The proposed multigeneration system brings a possibility to efficiently recover the waste energy for additional power generation and refrigeration production at different temperatures. Waste energy recovery by the ORC and GAX cycle as well as the integration of the GAX cycle with a cascade refrigeration cycle provide good potential for cleaner production of all products with improved efficiency, economics and environmental benefit. (C) 2019 Elsevier Ltd. All rights reserved.