The best balance of performance, longevity, and cost is Aluminum fins mechanically expanded onto Cupronickel 90/10 tubes. If budget is a constraint, Aluminum fins on AISI 316L stainless steel tubes is the next best option.
2. Structure & Casing (The Frame and Panels)
This supports the core and directs airflow.
- Hot-Dip Galvanized Steel (HDG): This is the standard and a good choice.
- Why it works: The zinc coating provides cathodic (sacrificial) protection to the underlying steel. The coating is thick and durable.
- Enhancement: For a seashore, specify an additional powder-coated paint system over the galvanizing. This creates a dual-layer defense: the paint is the first barrier, and the zinc is the second. This system is often more cost-effective than using all-stainless steel for the structure.
- Stainless Steel (AISI 304L or 316L):
- Why it works: Provides excellent corrosion resistance without needing a coating.
- Verdict: More expensive than HDG, but used for critical structural elements or in the most aggressive splash zones. 304L is often sufficient for the structure, but 316L is better.
. Fans & Louvers
- Fans:
- Fiberglass Reinforced Plastic (FRP): This is often the best choice. It is completely immune to salt corrosion, lightweight, and strong. Ensure the resin used is suitable for UV exposure.
- Stainless Steel (AISI 316L): An excellent, though more expensive, corrosion-resistant alternative.
- Avoid: Aluminum or coated steel fans, as they are more susceptible to damage and corrosion.
- Louvers (which guide air and prevent rain ingress):
- FRP or Stainless Steel are the preferred choices for the same reasons as the fans.
4. Fasteners, Bolts, and Hardware
This is a small but critical detail. Using the wrong fasteners can lead to catastrophic failures.
- Mandatory Material: Stainless Steel AISI 316 (or 316L).
- Never use: Galvanized, cadmium-plated, or especially carbon steel fasteners. They will corrode (“galvanic corrosion”) and fail, potentially leading to fan detachment or structural integrity issues.
Material Selection Guide for a Seashore Dry Cooling Tower
| Component | Recommended Material | Alternative (if budget is constrained) |
| Heat Exchanger Tubes | Cupronickel (90/10 or 70/30) | Stainless Steel AISI 316/316L |
| Heat Exchanger Fins | Aluminum | Aluminum |
| Structure & Frame | Hot-Dip Galvanized Steel with a Marine-Grade Paint System | Stainless Steel AISI 304L |
| Casing / Panels | Hot-Dip Galvanized Steel with Paint | Stainless Steel AISI 304L |
| Fans | Fiberglass Reinforced Plastic (FRP) | Stainless Steel AISI 316/316L |
| Louvers | FRP or Stainless Steel AISI 304/316 | Heavily coated aluminum |
| Fasteners & Hardware | Stainless Steel AISI 316/316L | None. Do not compromise here. |