DESIGN OF A WASTE HEAT RECOVERY SYSTEM FOR A 250KW DIESEL ENGINE.

ABSTRACT

In this project, calculations were conducted to measure the available waste heat available from a 250 Kw diesel engine. The technology selected for recuperating the waste heat was a shell and tube heat exchanger using air as the working fluid. Energy was to be recovered from both the cooling water and exhaust gas to heat air which in turn was used to dry grains. Two heat exchangers were used: one to recover heat from the cooling system and the other from the exhaust. These two heat exchangers were arranged in series, with air passing through both heat exchangers, before a Y connection directed it into the dryer. Interestingly, Engine speeds and loads affect the amount of heat that can be recovered from a diesel engine. While there are many working fluids in heat recovery such as Organic working fluids, for the purpose of drying cereals, heating air was found to be the most efficient method. This study also found that exhaust gas and cooling water in diesel engines have a good heat energy potential that should recovered and reused instead of going to waste.