Heat Exchangers

Heat exchangers are used to transfer heat from one medium to another. These media may be a gas, liquid, or a combination of both. The media may be separated by a solid wall to prevent mixing or may be in direct contact.Boilers, condensers, and evaporators are heat exchangers which employ a two-phase heat transfer mechanism. As mentioned previously, in two-phase heat exchangers one or more fluids undergo a phase change during the heat transfer process, either changing from a liquid to a gas or a gas to a liquid.In a gas furnace, the heat exchanger is located close to the combustion chamber. In an electric furnace, it is located close to the coil. The heat exchanger is heated by the heat source and warms the air outside. From there, a blower fan distributes the heated air through the ducts.