Poly-generation system with waste heat of low-temperature flue gas in power plants based on organic Rankine cycle

Abstract

Besides fossil energy and water resources, waste heat resources have attracted more and more attention because of their wide distribution and large quantity. This paper studies a system using low-grade waste heat emitted in a coal-fired power plants as the heat source, which coupled with low-temperature organic Rankine cycle (ORC), humidification and dehumidification and desalting system (HDH) and desiccanting cooling system (DCS) with different heat recovery system strategies, aiming at using low-temperature waste heat for power generation, desalting saline wastewater/sea water and providing space cooling for residential systems. The influences of control parameters on system productivity and system performance index were studied. In addition, the effects of different ORC working media on optimal system performance were also studied and discussed. Condenser exergy loss decreased by about 33% compared to an independent ORC system. In the range of control parameters studied, the total gain output of the poly-generation system was increased by about 47% compared to that of the independent system. The system is more productive when using n-Octane and Toluene, and has the highest system performance indicators when using R245fa and R113.