Advantages And Disadvantages Of Heat Exchanger

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1.1 GENERAL
As in any application there is fluctuation in heat load, this fluctuation affects optimal values of efficiency which causes decrement in system's overall efficiency.
1.2 HISTORY AND BACKGROUND
Heat exchangers are equipments that ease the exchange heat between two fluids which are at different temperatures while keeping them apart from mixing with each other. Heat exchangers in their purest sense have been around for as long as man has been cooking in pots and ovens. To understand this, one can remember that there are three types of heat transfer from on fluid to another: conduction, convection and radiation. The typical stew pot or clay oven exchanges heat between the heat source and the food through conduction.
The most common …show more content…

Controlled heat transfer is obtained in heat exchanger by inducing turbulence in fluid (either one or both) to maintain effectiveness of component and maintain overall efficiency of plant.
1.4 ADVANTAGES
By using variable load shell and tube type heat exchanger, controlled heat is transfer between two fluids. It will help to run the pump at constant load and mass flow rate. It will maintain overall efficiency of the pump and save auxiliary power of the whole plant.

1.5 …show more content…

It has been widely reported in literature that heat transfer rates in helical coils are higher as compared to those straight tubes. Due to compact structure and high heat transfer coefficient, helical coil heat exchangers find wide range of application. The heat transfer is enhanced by turbulence is governed by Reynolds number and Nusselt number. Experimental analysis for a helical coil heat exchanger was carried out and the results are compared with the straight coil under similar geometrical and operating conditions. The helical tube allows the fluid to be in contact for greater period of time so that there is an enhanced heat transfer compared to that of straight tube. The swirl of flow helps decrease the boundary layer thickness of the hot air flow and increase residence time of hot air in the inner tube. The enhancement efficiency and Nusselt number increase with decrease in pitch of wire. The most common type of heat exchanger in industrial applications is the shell-and-tube heat exchanger, shown in Figure. Shell-and-tube heat exchangers contain a large number of tubes (sometimes several hundred) packed in a shell with their axes parallel to that of the shell. Heat transfer takes place as one fluid flows inside the tubes while the other fluid flows outside the tubes through the shell. As the turbulence is increase rate of heat transfer between system to surrounding is increases. Often

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