Exhaust waste heat recovery from a heavy-duty truck engine: Experiments and simulations

Waste heat recovery using an (organic) Rankine cycle is important and promising technology for improving engine efficiency thereby reducing the CO2 emissions due to heavy-duty transport. Experiments were performed a with water waste from exhaust gases of Diesel engine. The experimental results used calibrate validate steady-state models main components in cycle: pump, pump bypass valve, evaporator, expander, condenser. Simulations evaluate performance over wide range operating conditions three working fluids: water, cyclopentane, ethanol. Additionally, simulations these fluids typical long haul truck driving cycle. predicted net power output as fluid varied between 0.5 5.7 kW, where optimal expander speed was dependent on point. cyclopentane 1.8 9.6 kW that ethanol 1.0 7.8 kW. Over cycle, total recovered energy 11.2, 8.2, 5.2 MJ ethanol, respectively. These values correspond recoveries 3.4, 2.5, 1.6%, respectively, relative requirement contribution this paper presentation data complete cycle-based WHR system coupled component simulations, allowing realistic estimation under type system.