Tips for Choosing the Right Heat Exchanger
Humans have dabbled in alloys and iron for 4,000 years. The additions of elements such as chromium and titanium gave rise to the stainless steel heat exchanger as used today, but despite the best efforts of engineers, it is far from indestructible.
It’s in the News: Feb. 5, 2020 Johnson Controls announced that it has added fully integrated, factory-built and installed wrap-around heat exchangers to its YORK® Solution™ Indoor and Outdoor air-handling units, meeting a growing need for energy-efficient dehumidification methods in a compact footprint.
For industrial-scale heaters to perform well, heat exchanger materials must be compatible with the environment in which they are used. Different humidity levels and the presence of airborne corrosives dictate the type of metal used in heater design. The application and environment in which these heaters are used are critical in determining what exchanger type should be used. Here are some things to keep in mind when selecting an industrial heater to ensure the heat exchanger will perform well over the long haul.
Metals Pros and Cons
- Aluminized Steel
- Pro: The standard material used in a heat exchanger is aluminized steel, which works well in the majority of applications.
- Con: In humid environments, aluminized steel will corrode much more quickly than stainless steel.
- Stainless Steel
- Pro: It helps prolong the life of heat exchangers. While it’s a very robust product, it’s really best suited for high-humidity, noncorrosive applications, such as greenhouses or locations with consistently high levels of humidity such as the south eastern portion of the United States.
- Con: In a corrosive environment it’s likely to break down. It would not be a good choice for a pool environment where chlorine is present.
- 409 Stainless Steel
- Pro: 409 stainless steel offers the best expansion rates and heat transfer. Originally developed for use in auto exhaust systems that needed to withstand condensate in short commutes in cold environments. It is robust, proven and reliable. Its thermal expansion is less than other types of stainless, therefore it is less prone to cracking. It is also easier to weld, a key factor in construction of industrial heaters.
- Con: More expensive than other types of steel but will increase the longevity of the heat exchanger.
- Pro: has many desirable properties for thermally efficient and durable heat exchangers: excellent conductor of heat, corrosion resistant, biofouling resistant, maximum allowable stress and internal pressure, high melting point, alloyability, ease of fabrication, and ease of joining.
- Con: Expensive
- Other Metals
- Carbon Steel
- Pro: As the carbon percentage content rises, steel has the ability to become harder and stronger
- Con: Less ductile, reduced weldability, lower tmelting point.
- Nickel Alloy
- A large variation in alloys exist each with its own pros and cons.
- The two most useful properties of the metal are corrosion resistance and strength-to-density ratio, the highest of any metallic element. Used for pool heaters.
- Carbon Steel
As defined above, the application or the physical geographic location will help determine the preferred heat exchanger. The ROI (return on the investment) will be determined based on: initial cost, the type and frequency of routine maintenance, and the length of warranty. For help in deciding which heat exchanger is correct for your new, replacement or retrofit project, contact your Access Inc sales engineer.
Modified from the original written by Jamie Tuinstra, product manager for Modine Manufacturing Co. and originally published HERE