Theoretical and Experimental Analysis of Waste Heat Recovery Effectiveness of a Diesel Engine

The study utilized the exhaust gas from a diesel engine to preheat water in the constructed shell and tube heat exchanger.

The theoretical analysis of the heat exchanger was carried out using the Log Mean Temperature Difference (LMTD) method. The Volumetric flowrate of the water was manipulated using a valve and the resulting output temperature of water leaving the heat exchanger was recorded. Experimentation was carried out to determine the effects of volumetric flow rate on the output temperature and the effectiveness of the heat exchanger. After the test and data analysis, it was discovered that that at flow rate of 3.0 Liter per minute (LPM) the effectiveness of the heat exchanger was peak at 43.34%. The volumetric flow rate of water is inversely proportional to the output temperature of water and it was also established that the effectiveness of the heat exchanger depends on output temperature of and the mass flow rate of the water. Also it was proven that by preheating water before it enters the boiler of the Rankine cycle the efficiency of the cycle increases.