Effect of Diesel-engine Operating Conditions on Performance of Waste Heat Recovery Cycles: A 4E Analysis

In waste heat recovery from a heavy-duty diesel engine, with a focus on engine speed’s impact, is explored. The critical problem of enhancing energy efficiency and reducing emissions through waste heat utilization is addressed. Waste heat in internal combustion engines, vital for sustainable energy use and environmental preservation, is investigated. Experimental analysis and thermodynamic modeling introduce Organic Rankine Cycle (ORC), Steam Rankine Cycle (SRC), and Combined Steam and Organic Rankine Cycle (CSO) for waste heat recovery. A non-linear relationship between engine speed and waste heat is identified.  Waste heat increases up to 1600 rpm and decreases thereafter. The CSO cycle outperforms ORC and SRC cycles, achieving 43.4% higher efficiency. Fuel energy savings demonstrate CSO’s superior economy, along with excellence in Annual Carbon Dioxide Emissions Reduction (ACO2ER). Waste heat recovery knowledge is advanced by introducing the efficient CSO cycle, contributing significantly to existing research.