Abstract

As energy becomes more expensive, and the ramifications of wasting it become more evident via climate change, the recovery of waste heat is becoming more important. Waste heat is produced in many industrial processes. Most energy conversion processes involve the production of heat as a by-product, which is usually wasted. The waste heat recovery in the system from the high temperature gases can be taken into account as a potential option to enhance the process efficiency of energy in industry. By using the recovery systems, waste heat can be captured, whereas the efficiency values of energy and exergy can be developed will provide the interrogators with knowledge about how effectually and competently a sector utilizes its resources of energy. Large quantities of hot flue gases are generated from boilers, kilns, ovens and furnaces. If some of the waste heat could be recovered then a considerable amount of primary fuel could be saved. The energy lost in waste gases cannot be fully recovered. The essential fact is not the amount of heat, but rather its “value”. The mechanism to recover the unused heat depends on the temperature of the waste heat gases and the economics involved. The waste heats can be classified as waste heats of middle and low temperatures. Some available power plants are suitable to recover the waste heats.