The heat exchanger is a device that transfers heat from one medium to another, i.e., liquids, vapours, or gases—of different temperatures. Depending on the type of heat exchanger employed, the heat transferring process can be gas-to-gas, liquid-to-gas, or liquid-to-liquid and occur through a solid separator, preventing mixing of the fluids or direct fluid contact. Heat exchangers can improve a system’s energy efficiency by transferring heat from scenarios where there is no need for other methods to be usefully used.
In many engineering applications, it is desirable to increase the temperature of one fluid while cooling another. A heat exchanger economically accomplishes this double action. Heat exchangers are used extensively in fossil-fuel and nuclear power plants, gas turbines, heating and air-conditioning, refrigeration, and the chemical industry. The devices have different names when they serve a particular purpose.
Heat exchangers classifieds according to flow arrangement and construction features.
• Parallel-flow and counterflow
• Compact heat exchanger
Many industrial processes call for a certain degree of heat to function; however, great care must keep these processes from getting too hot. Within industrial plants and factories, heat exchangers must keep machinery, chemicals, water, gas, and other substances within a safe operating temperature. Heat exchangers may also be used to capture and transfer steam or heat exhaust that is released as a byproduct of a process or operation so that the steam or heat can be better used elsewhere, thereby increasing efficiency and saving the plant money.