Design of Waste Heat Recovery System from Incinerator for Water Heating Application: The Case of Jimma University Referral Hospital.

Abstract

Energy recovery system of hospital waste heat to useful energy units represents a substantial part of the whole technology which enables to utilize heat contained in flue gas (off-gas) from incinerators or combustion chambers as much as possible. This thesis deals with Modeling Waste heat recovery system from incinerator for water heating application: the case of JURH. For high temperature applications, there are many sources of thermal waste heat, and several recovery systems and potential useful applications have been proposed by researchers. Therefore in this research work an attempt has been made to design and analyses of shell and tube heat exchanger for water heater. The amount of hot water supplied to the hospital throughout the day and the energy needed to heat the demanded hot water. This energy mainly comes from the waste which is discarded from hospital including administrative staff by incineration. A bomb calorimeter is used to determine the energy content of each waste. The total energy available is 26596.6MJ or 7387.95kwh and the energy needed to heat or raise temperature by 1℃ of one liter of water is 4.186kj/kg. A heat exchanger is a heat transfer device to provide heat transfer thermal energy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid available, at different temperatures. The flow is counter flow; on the other hand, the hot and cold fluids enter the heat exchanger at opposite ends and flow in opposite directions. This means One fluid runs through the tubes, and another fluid flows over the tubes (through the shell) to transfer heat between the two fluids. The design procedures are followed by thermal design specification of shell and tube heat exchanger. The energy and cost saving potential is closely linked to the flow of heat in the hospital incinerator in most cases. The basic idea behind waste heat recovery is to try to recover maximum amounts of heat in the incinerator and to reuse it as much as possible, instead of just releasing it into the air or a nearby river. The saving of energy in general became therefore mandatory, being the recovery of the heat from waste flue gases of incineration plants of hospitals one of the possible ways of saving energy. Thus by recovering flue gas 475.25kwh of energy per day is saved and converting this energy in to fee 256.63ETB per day is saved.