Waste Heat Recovery as an Alternative Energy Source

摘要

Heat recovery can substantially lower the operating costs for a manufacturing facility byutilizing the heat generated from one process for another. Most manufacturing processes requirea specific amount of heat by elevating the temperature of a fluid or a substance to a given leveland once that heat is used for the process it is rejected to the atmosphere. Generally only a smallportion of the energy is used for the actual process. It seems illogical to utilize only a portion ofthe energy and wasting the remaining which could be used for something else. Heat recoverysystems use that energy being rejected, which was already paid for by the company, for additionalpurposes that will lower the company’s cost of operation. Heat can be extracted from solids,liquids, and gaseous media. The classifications of waste heat recovery are low, medium, and hightemperature ranges which fall within the temperature ranges of below 450°F, 450-1200°F and1200° + °F respectively. For the low temperature range there is no applicability for recoveringwork, and the heat that is recovered is used for things such as preheating the intake air, heatingdomestic water supplies, or producing low pressure steam. The medium temperature range can beused to produce some mechanical work. The high temperature range could be used to produce asubstantial amount of mechanical work that could possibly be used to drive a steam turbinethrough the use of an industrial boiler.Several heat reclamation devices are available commercially. The efficiency of thesedevices involves several factors. However, technical and economic feasibility of heat recovery isgoverned by the physical location of the heat source and sink, timings of availability and need forusing waste heat, and the overall efficiency of the heat recovery system. The purpose of thispaper is to demonstrate that even though waste heat is generated in a manufacturing facility, it isnot always feasible to use it for all of the applications and when it is feasible it cuts costs.