Heat exchangers are heat transferring devices used to move heat from one gaseous or liquid substance to another for the purpose of either heating or cooling a substance for another process. Constructed with thermally conductive plates or tubes, heat exchangers are used to transfer heat from water to water, air to air, water to air or steam to other liquids – such as lubrication oil.
Many industrial processes require heat exchangers to perform a crucial role in the design, operation and maintenance of heating systems, air-conditioning systems, vehicle operation, power generation, refrigeration, chemical processing, offshore oil rigging and engineering systems. They can also be used in the process of waste heat recovery in industrial facilities. Read More…
There are a number of varieties of heat exchangers which are used according to their location and purpose. They are typically constructed with a shell and tube design or a flat plate design, in which fluids, steam and/or air flow through heat-conducting tubes or conductive plate-walled cavities. Plate heat exchangers can be configured as plate and frame heat exchangers or flat plate heat exchangers, while shell and tube heat exchangers in a tubular design may be designed as tube heat exchangers, finned tube heat exchangers, oil coolers or spiral heat exchangers.
Water to water heat exchangers and marine heat exchangers typically have a shell and tube or spiral design, while air to air heat exchangers and water to air heat exchangers are generally configured in a plate, flat plate or plate and frame design.
Although tubular and plate heat exchangers are configured differently in terms of layout, they both apply the same principles of thermodynamics. The tube walls or conductive metal plates are partitions, acting as thermal conductors between the two fluids or gases while keeping the substances from intermingling. Stainless steel is commonly used as a wall or plate as it is a highly durable metal and is able to withstand the pressure and high temperatures that typically come with the heat exchange process while still acting as a conductor.
A hot solution flowing on one side of the barrier transfers its heat to a cooler solution flowing on the other side, temporarily creating thermal stress within the plate or wall. Thermal energy flows in the direction of the cooler substance from the hotter in the substance’s attempt to reach equilibrium on the surface. The size of the surface area of these conductive partitions affects the speed and efficiency of the process.
The larger the surface area the substance is exposed to, the faster and more efficient the heat transfer; this is why plate heat exchangers are used to transfer heat between air or gases, which do not transfer heat as easily as liquids. Heat exchanger manufacturers typically construct exchangers from durable, corrosion-resistant materials such as steel, titanium, copper, bronze, stainless steel, aluminum or cast iron.
Typically power generation facilities rely on heat exchangers to keep processes from dangerously overheating and/or to recycle process heat. Other industries that integrate heat exchangers into equipment and products include aerospace, chemical, marine, semiconductor, petrochemical, electronic and automotive. Another common use for heat exchangers is the process of waste heat recovery which is used to capture excess heat from one industrial process and use it in another process requiring heat.
This environmentally conscious manufacturing practice may also be used to cool process fluids, or it may be used to cool air for refrigeration and air conditioning. It saves money and energy as it uses an existing source of heat thus eliminating the need to use an electrical supply or fossil fuels to create heat. Heat exchangers are also important for process cooling and waste heat recovery in pharmaceutical, food processing, water treatment, textile manufacturing, pulp and paper and steel manufacturing processes.