Waste Heat Recovery System for a Turbocharged Diesel Generator at Full and Part Load Operating Conditions Using Rankine and Organic Rankine Cycles 2018-01-1370

Waste Heat Recovery System (WHRS) is used to extract heat from the exhaust gas from internal combustion (IC) engines to produce additional power with increase in overall efficiency of the engine. Amongst various WHRS, this paper focuses on WHRS using Rankine Cycle (RC) and Organic Rankine Cycle (ORC). A 100 kVA (80 kW engine) diesel generator was used for this research. Water, R245fa, and R134a were used as the working fluids for the cycle. To assess the performance of WHRS, the system was designed for 80 kW, 70 kW and 60 kW loads and then, for each designed load the WHRS was run for other loads and then compared. Assessment provide simulation results of RC and ORC using Engineering Equation Solver (EES) software. It was found that using water as the working fluid around 20% additional power was achieved. But it limited the working range of the system making it unsuitable for lower loads of 10 and 20 kW for this generator. R245fa and R134a on the other hand provided comparatively less efficiency but covered wide load range. R245fa showed power improvement of 11.2%, and R134a showed a power improvement of 7.0% at 80 kW. At lower powers of 10 and 20 kW the additional powers were 0.84 kW, 1.35 kW and 0.2 kW, 0.43 kW, for R245fa and R134a, respectively and water as the working fluid could not produce any additional power at these lower loads.