INTRODUCTION

The I.C engine is a device which converts the chemical energy of fuel into heat and again heat energy in to mechanical work. It is the fact that the total heat supplied to the engine in the form of fuel approximately only 30-40% get converted in to useful mechanical work and remaining almost 70% of the energy released from fuel due to combustion is lost mainly in the form of Heat. Approximately 25-30% of the total energy generated by the engine is dissipated in the form of Exhaust loss energy. Increase in economy the energy demand also increases which results in more usages of fossil fuels which causes the emission of harmful greenhouse gases. Large amount of heat is released in the atmosphere from the engines without utilizing for any purpose. If some amount of this waste heat could be recovered it possible to reduce the primary fuel required. Waste heat utilization is the major source of cost saving. If exhaust gases of engines are directly released into atmosphere it will not only waste heat but also causes the environmental problems, so it is required to utilize the waste heat for useful work to increase the efficiency of engine.The- recovery and utilization of waste heat from engine results in reduction in fuel consumption, reduction in waste heat loss and engine emission, increases the engine efficiency. It is necessary that continuous and serious efforts should be taken for conserving this waste heat by using proper waste heat recovery techniques. This project shows, Heat available from engine exhaust and existing and possible waste heat recovery systems for I.C engine .Benefits of waste heat recovery from engines can be broadly classified in two categories

Direct Benefits:

Recovery of waste heat has a direct effect on the combustion process efficiency. This is reflected by reduction in the utility consumption and process cost.

        Indirect Benefits:

1) Reduction in pollution: A number of toxic combustible wastes such as carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and particulate matter (PM) etc, releasing to atmosphere. Recovering of heat reduces the environmental pollution levels.

2) Reduction in equipment sizes: Waste heat recovery reduces the fuel consumption, which leads to reduction in the flue gas produced. This results in reduction in equipment sizes.

3) Reduction in auxiliary energy consumption: Reduction in equipment sizes gives additional benefits in the form of reduction in auxiliary energy consumption