Fluids and parameters optimization for the organic Rankine cycles (ORCs) used in exhaust heat recovery of Internal Combustion Engine (ICE)

• Published in: Energy (Oxford) Vol. 47; no. 1; pp. 125 - 136
• Main Authors: Tian, Hua, Shu, Gequn, Wei, Haiqiao, Liang, Xingyu, Liu, Lina
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2012; Elsevier
• Subjects: Applied sciences; boiling point; combustion; Electric power generation; electricity; Energy; evaporation; Exact sciences and technology; Exhaust; Exhaust gas; Fluid dynamics; Fluid flow; Fluids; fuels; generators (equipment); Heat recovery; heat transfer; Internal Combustion Engine (ICE); Internal combustion engines; mass flow; Organic Rankine cycle (ORC); production costs; Techno-economy; temperature; Working fluid; Working fluids; Exhaust gas; Working fluid; Organic Rankine cycle (ORC); Internal Combustion Engine (ICE); Techno-economy
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2012.09.021

An Organic Rankine Cycle (ORC) system used in the Internal Combustion Engine (ICE) exhaust heat recovery was proposed and techno-economically analyzed based on various working fluids. It is significant to recover ICE exhaust heat (about one third of energy generated from the fuel) by ORC system. In this paper, the suitable working fluids have been screened and recommended for the ORC system, among 20 fluids (boiling point temperature range from −51.60 to 32.05 °C) analyzed on the rated condition of one popular commercial diesel generator set. The cycle parameters, including the thermal efficiency (ηth), the expansion ratio (v2/v1), the net power output per unit mass flow rate of hot exhaust (Pnet), the ratio of total heat transfer area to net power output (A/Wnet), and electricity production cost (Epc), have also been analyzed and optimized. Results show that R141b, R123 and R245fa present the highest ηth and Pnet values ranging from 16.60% to 13.30% (ηth value), and from 60 to 49 kJ/kg (Pnet value). Meanwhile, the three fluids also express the lowest Epc values ranging from 0.30 to 0.35$/kWh, and lowest A/Wnet values ranging from 0.436 to 0.516 m2/kW. The optimum evaporating pressures for R141b, R123, R245fa are ranging from 2.8 MPa to 3.6 MPa. Research Subject: Waste heat recovery technology in internal combustion engine; The key technology on the improvement of ICE efficiency. ▸ We proposed an organic Rankine cycle recovering Internal Combustion Engine exhaust heat. ▸ We established techno-economically model and did analysis based on 20 working fluids. ▸ System performance express better at high evaporating pressure. ▸ R141b, R123 and R245fa present the highest thermal efficiency ηth and Pnet values. ▸ R141b, R123 and R245fa express the lowest electricity production cost Epc and A/Wnet values.