Enhanced thermal efficiency in off-highway vehicles using a reheat organic Rankine cycle with a two-stage radial turbine and wet fluids

Off-highway vehicles contribute significantly to environmental pollution, underscoring the need for effective waste heat recovery solutions. Organic Rankine cycles (ORC) recover waste heat from exhaust emissions, converting it into useful power, which helps reduce fuel consumption and harmful emissions. This study presents a reheat ORC system with a two-stage radial turbine using R21, a wet fluid, at various reheat pressures. The results show that using R21 at a reheat pressure of 1100 kPa leads to substantial improvements in turbine power (39.5%), efficiency (21.54%), and system size (86.27%) compared to the dry fluid R123 with conventional ORCs. Additionally, engine power and brake specific fuel consumption (BSFC) improved by 17% and 15.73%, respectively, after implementing the reheat ORC.