heat exchanger design

Heat exchangers are used for maintaining the required temperature in the applications. The basic principle on which these devices work is the temperature difference between two mediums. These devices transfer heat between two mediums like gas to gas, liquid to liquid, liquid to gas, or gas to liquid. These devices are manufactured using material that can conduct heat efficiently. These include metals like aluminum, copper, stainless steel, and non-metal materials like plastic and ceramics also.

For the simple applications like heating or cooling of our homes or offices, usually, heat exchanger manufacturers offer ready-to-use products which you can start using immediately after installation. But for the complex applications, you need to decide what type and configuration of the device would be needed. Thermal engineers study the requirements and suggest the correct type and configuration of the device.

Designing Heat exchangers

Several aspects are taken into consideration for the heat exchanger design and these include the required volume of the heat to be transferred, heat transfer rate, nature of the application, space to fix the device, material selection, heat transfer medium selection, cost and maintenance issues.
Heat exchangers can be designed in various shapes and sizes. Based on the shapes, these can be classified as plate, plate fin, tube, tube fin, shell and tube, double pipe types. Thermal design engineers calculate the volume and rate of the heat transfer is required. Based on these parameters they will recommend the exact type and size of the device.

Selecting the type of heat exchanger

The nature of the application plays an important role while deciding what type of device would be appropriate for the application. In industries like petroleum refining where huge volume of heat transfer is required shell and tube types of devices are used. While separating oil from gas and water, the heat recovery process in the petroleum industry uses this type of device. In applications where a high rate of heat transfer is required but there is a small place to fit the device, then plate or plate fin type of heat exchangers are recommended because these types of devices are the most efficient design.

Selecting the material

Different materials like copper, aluminum, stainless steel, plastic and ceramic are used for manufacturing heat exchangers. Metals like copper, aluminum, and stainless steel are good conductors of heat and are used widely for manufacturing these devices. When the heat transfer is between very high-temperature mediums, metals can melt down, in such cases ceramic is considered an ideal material for manufacturing the device because it can withstand high temperatures. The pharmaceutical and food industry use high-grade stainless steel to address the concern of contamination. If the heat exchangers are using tubes then the material of the tube, the diameter, length, and the thickness of the tube are selected based on the required heat volume and heat transfer rate.

Selecting heat transfer medium

Water is used widely as a heat transfer medium in the liquid heat exchangers because it is a cost-effective solution. But for the electronics cooling applications, freshwater is not considered an ideal solution because the ions present in it can cause short circuits and damage the equipment. For applications where the required heat transfer rate is low and generates a low volume of heat, and there is a small place to fix the device, air to air heat exchangers are considered an ideal solution.

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