The heat exchanger is essentially a means of transferring heat between two fluids. The distinguishing feature of the heat exchanger is that it makes the heat transfer between these two fluids in liquid or gaseous state by preventing the substances from mixing with each other. Generally, the plate or other heat transfer surfaces used in the heat exchangers both separate the fluids from each other and allow the transfer of heat from one fluid to another. This heat exchange can be heating, cooling or bidirectional simultaneously.