Mahyar Ebrahimi - Department of Materials Science and Engineering of Sharif University of Technology, Tehran, Iran
Marzieh Akhoundi - Faculty of Aerospace Engineering K.N.Toosi University of Technology, Tehran, Iran

This paper presents a comprehensive theoretical, experimental, and economic study on the application of nanofluids as heat transfer fluid in waste heat recovery systems. The research work was conducted in a steel-making complex in which a plate heat exchanger had been used to recover heat from hot process water. The system was theoretically modelled and the effects of using nanofluids as heat transfer fluid were investigated. Nanofluids with ZnO, Al2O3, SiO2, and CuO as nanoparticles and water as base fluid were used in the analysis. It was found that the best performance is obtained with Al2O3 nanofluid. This can increase the effectiveness of the plate heat exchanger by up to four per cent. Based on this analysis, the existing heat transfer fluid (demineralized water) was replaced by Al2O3 nanofluid. The experiment confirmed the theoretically predicted increase of the heat exchanger’s effectiveness but this increase was a little lower than what was expected. Finally, an economic analysis was done using the net present value method. This economic analysis was performed twice: once with local market prices and once with global market prices. The results show that the project is economical based on global market prices.

Economic Analysis, Net Present Value, Heat Recovery Nanofluid, Case Study, Nanofluid