Exhaust Heat Energy Recovery Through Use of Absorption Cooling of Internal Combustion Engine Intake Air

Further improving energy efficiency in internal combustion (IC) engines is the research-topic for a large number of investigators. This project covers the integration of an IC-based cogeneration with a vapor-absorption chiller. Heat from the cogen is fed to the generator of the absorption chiller. It is to improve performance and efficiency of internal combustion engines for use in motor vehicles.Less than one third of the total energy in a given amount of fuel is transferred into the rotational motion that drives vehicles forward. The remainder is either used to overcome friction and drive mechanical devices such as the alternator and water pump or is rejected as heat through engine cooling and exhausted gas. The heat rejection from the exhaust is due to the Carnot law and it is low grade heat that cannot be efficiently converted to work in the engine and thus, requires a second system for energy recovery. The two forms of rejected heat each account for approximately a third of the available energy.Traditional methods of improving performance such as increasing capacity and air intake through forced induction also results in more fuel being consumed. Improving fuel efficiency meanwhile has resulted from running the engines leaner and downsizing engines. However the current methods have not taken advantage of the energy supply available in the exhaust stream.Harnessing the thermal waste energy in the exhaust can be achieved through integration of a heat exchanger in order to power a vapor absorption cycle for the purpose of cooling intake air. This cooler, denser charge improves both volumetric and mechanical efficiency of engines with the outcome being improved performance, better fuel economy and lower emissions.Recommendations for future work and other applications will be provided based on the analyzed results contained in the body of this paper.Copyright © 2012 by ASME