Material decides service life
The plate material decides how long a heat-recovery core lasts and what duty it can safely handle. Choosing it against the real air quality on site is one of the highest-return decisions in a recovery project, because a wrong grade fails quietly at an edge or joint long before its time.
Aluminum and hydrophilic foil
Aluminum and hydrophilic aluminum foil are the default for clean indoor ventilation. They conduct heat well, are light, and cost less, but aluminum is limited by temperature and by corrosive or coastal atmospheres. For most fresh-air and HVAC duties with clean air, aluminum is the right balance of performance and price.
Stainless steel grades
304 stainless steel adds corrosion resistance for mildly aggressive exhaust and higher temperatures than aluminum tolerates. It suits many industrial and process streams that are not strongly acidic or chloride-rich. For the harshest duty, 316L stainless resists chlorides, sulfates, and many chemicals, and is the usual choice for food, pharmaceutical, coastal, and chemical-plant exhaust where longevity matters more than first cost.
Coatings and linings
Protective coatings and polymer linings extend the life of a standard grade in humid or lightly corrosive streams, and food-grade coatings support wash-down regimes in hygiene-sensitive plants. The rule is to match the alloy to the worst-case condition, not the average, because localized attack at a plate edge or weld is what usually ends a core's service life.
Verify before approval
Always request the material certificate and the design temperature envelope before approving the order, and confirm the grade against the actual gas composition rather than accepting a generic "stainless" label. A short verification step prevents the most common and most expensive field failures.
Explore more
- High-temperature heat exchanger materials
- Process exhaust heat recovery in food and pharmaceutical plants
- Industry articles
Key takeaway
If in doubt between two grades, choose the more resistant alloy for the exposed core and save cost on the frame and supports. The plate is the part that fails first, so it deserves the better material, while the structural steel around it can be specified more economically.