Stainless Steel Coil Advantages

Stainless steel is initially produced in slab form and then undergoes a conversion process using a Z mill, which converts the slab into coil before further rolling. These wide coils are usually made around 1250mm (sometimes slightly wider) and are called "edge coils".

Often, using stainless steel components seems like an easy solution to coil corrosion. You may see signs of corrosion in the fins or tubes or other parts of the system, and it seems your best bet is to replace the coil with stainless steel, which will permanently fix the corrosion problem. While this seems like a simple solution to a major problem in HVAC, industrial and commercial systems where coils are found, the answer to the question "Should I make all stainless steel coils?" Much more complicated.

While stainless steel does have excellent corrosion resistance, its heat transfer properties can be poor when used in heat exchangers. Therefore, solving the corrosion problem by using stainless steel may cause other system problems. When changing the system material to stainless steel, performance degradation, exceeding fan or motor capacity, and exceeding the space or structural constraints of existing installations are all possible. Finally, there's economics - is a stainless steel solution a viable commercial option for installation?

As a systems engineer, you face a dilemma: meet overall system constraints, address corrosion issues, and stay on budget to keep projects moving forward. Often these priorities conflict with each other, but the assessment and balancing of these goals is where the Super Radiator can help.

To better understand the potential impact of using an all stainless steel heat exchanger, let's evaluate an example 400,000 BTU/HR (33 tons or 119 kW) cooling coil. For example, we will use 45°F water and a 36” x 45” coil with standard copper tubing and aluminum fins. The unit's coil is 12 inches deep, weighs 320 pounds, and has a cost factor of 1.0. This is our base unit and is the component currently installed in the system.

In some systems, stainless steel or other highly corrosion-resistant materials may be the only option: high temperatures, abrasive environments, extremely aggressive chemical solutions. In many cases, a basic coil with a high-quality coil coating can solve most coil corrosion problems. Let's evaluate the impact of this option.

Using a coil coating has little effect on the thermal performance of the coil, according to the Super Heatsink study. However, coatings do incur additional costs compared to uncoated coils. Electrodeposition (E-coat) and baked phenolic resins (such as Heresite P413) are the most common premium coil coatings. The coated example coil has a cost factor of 1.3. Prices are higher than bare coils, but coatings are an excellent choice for addressing corrosion issues, meeting system performance needs, and fitting spaces.