Heat Transfer, An Overview

This paper analyzes the growing need of efficient way of heat transfer in present day environment. The present standard of living became possible by the energy available in the form of heat obtained from a variety of sources, for example fuels. The process of this energy conversion falls under the scope of Thermodynamics. Thermodynamics is main subject of mechanical engineering that deals with the end state of processes involving heat or work transfer and provides no information concerning the nature of the interaction or the time rate at which it occurs. In practical or industrial applications, time factor i. e. the rate of energy (called power) transferred plays a very important role. That is why an efficient way of heat transfer is necessary. So the equipments used in heat transfer are designed according to the rate of heat transfer considering practical aspects. There is a long list of various equipments where heat transfer rate influences their operation. Heat is in fact, a low grade energy where work is high grade energy. The driving force which causes the transfer of energy as heat is the temperature difference between the systems. Other parameters which affect the heat transfer are material properties like conductivity, emissivity, flow parameters like velocity of flow and geometry In addition to the temperature difference. Some other transport processes of the heat transfer the transfer of mass, electrical energy and momentum. The amount of energy transferred as heat can be calculated from the law of conservation of energy (First law of Thermodynamics)