Heat exchangers are used in many chemical and industrial processes, including refrigeration and nuclear power generation. Because of the increasing need for energy, heat exchangers are seen as vital to keep many businesses and industries going. The thermal performance and efficiency of heat exchangers depend on several aspects, including the materials used throughout the system. A good materials engineer knows when to approach suppliers of stainless steel tubing and when another material may be considered more appropriate for a particular application.
General procedure for materials selection
When identifying the best material to use for a specific heat exchanger application, engineers and heat exchanger designers first identify what is required of the heat exchanger. The operating temperatures, pressure, flow rate, and the nature of the fluids are considered, as well as conditions during startup and shutdown. The method used for connecting tubing may also influence the material selection.
Choosing the most appropriate material also involves coming up with a strategy for the evaluation of candidate materials, taking into consideration the cost and reliability. If you cut corners and take cheaper materials, be prepared to rectify any problems down the line.
Factors to consider
When selecting the best materials for a heat exchanger, engineers consider the following:
- Physical Properties – Heat transfer coefficient must be high; thermal expansion coefficient should be low and compatible with materials utilised for tubing
- Mechanical Properties – The material must have high impact strength and fracture resistance as well as good tensile and creep properties.
- Corrosion Resistance – The material must be resistant to corrosion and have tolerance to any chemistry that is a result of the combination of tube material and the fluids they are transporting.
Engineers and heat exchange designers have a lot to consider when choosing the best material to use for a heat exchanger system. Apart from making comprehensive evaluations of candidate materials, they also need to assess the material in view of its initial cost and maintenance. Selecting the right materials is a long but necessary process to ensure a reliable and efficient heat exchanger.