Plate Heat Exchanger Principle and Its Applications
Heat exchangers are devices that permit efficient exchange of thermal energy between two fluids. Historically, standard shell-and-tube heat exchangers have been used for this purpose. However, in today’s world, a new type of heat exchanger is gaining popularity - the plate heat exchanger (PHE). This article will discuss the basic principle of PHEs and popular applications of this device.
The principle of PHEs involves the use of a set of thin, metallic plates arranged in a compact stack (known as the ‘plate pack’). Each of these sheets is laser-welded along its edges to form a permanent and leak-proof seal. There are circular openings or ‘pockets’ on both sides of each plate for the flue gases (or process media) to pass through. The entire plate pack is sealed in a frame to form the complete PHE assembly. Heat is transferred across the plate as the streams of medium flow in parallel. Thus, the PHE acts as an effective medium for transferring heat between the two fluids.
PHEs are preferred over shell-and-tube heat exchangers because they are smaller, more efficient, and less expensive to manufacture. They can be configured in various ways, making them suitable for many applications. Common applications of PHEs include conden-sation (in refrigeration systems), steam-water heating, and boiler-firebox heating. PHEs are also used in some industrial processes to remove heat from process media such as heat transfer oils. Other applications include heat reclaimers, evaporators, heat pumps, and fin-fan coolers.
PHEs have several advantages over shell-and-tube heat exchangers, one of which is their superior heat transfer efficiency. This is mainly due to the turbulence caused by the triangular plate corrugation. Although PHEs may have a smaller heat transfer surface area, their superior flow characteristics allow them to transfer more heat per surface area, which increases their overall thermal efficiency.
The construction of PHEs is relatively simpler compared to shell-and-tube heat exchangers, as there are fewer parts required for their assembly. This results in a much lower cost of installation and operation. PHEs are also much easier to maintain, as they are accessible from the outside. This makes it easier to check for blockages or other issues that may arise.
In conclusion, plate heat exchangers are becoming increasingly popular for efficient thermal energy transfer. They are smaller in size, more efficient and cheaper to manufacture than shell-and-tube heat exchangers. In addition, their versatility and reliable performance make them invaluable for various applications in the process industry.
