Thermodynamic and Thermoeconomic Optimization of an Organic Rankine Cycle for Heat Recovery from a Cement Plant

In this study, optimization of a waste heat recovery system (WHRS) that works by an organic Rankine cycle (ORC) from a cement plant is investigated. Energy and economic models of the system are presented. The energy model and thermo-economic model are developed according to the first law of thermodynamics and specific exergy costing method respectively. To design ORC, there are two major issue that are considered here. One issue with recperator and another without that. The first law of thermodynamic as an objective function to maximize the efficiency and economic objective function to minimize the total cost of electricity produced are used. Optimization methodology is based on genetic algorithm and performed by EES software. Also in order to determine the effect of the fluids on the cycle, three fluid included R245fa, R123 and n-pentene are examined and their results is discussed. The results showed that in the case of thermodynamics optimization without recuperator, R123 with 17.76% has the highest efficiency compared with the other fluids and with recuperator versus R123 with 20% is the best fluid. Moreover in thermoeconomic optimization R123 has the lowest total production cost compared with the other fluids with 0.199€/hr and 0.315€/hr in cycle without recuperator and with recuperator respectively. Here, it can be concluded that for the thermal recovery of medium-temperature sources, in thermodynamic optimization and thermoe-conomic optimization, R123 can be identified as a good choice for ORC cycles.