TYPES OF FILLS
Fills are categorized by their heat transfer mechanism and material.
1. Splash Fill
- Mechanism: Relies on splash action. Water falls onto staggered layers of bars, grids, or slats, breaking into smaller droplets.
- Construction: Grids of PVC, wood, or polypropylene.
- Advantages:
- Excellent for dirty water (large passages resist clogging).
- Low pressure drop.
- Durable, easy to clean.
- Disadvantages:
- Lower thermal efficiency per unit volume compared to film fill.
- Requires more tower volume for the same cooling duty.
- Typical Use: Industrial applications with suspended solids (e.g., steel mills, river water), or in very cold climates where ice formation is a concern.
2. Film Fill
- Mechanism: Relies on film formation. Water spreads into a thin, continuous film over closely spaced, corrugated sheets.
- Construction: Sheets of PVC or polypropylene, typically arranged in blocks.
- Advantages:
- Very high thermal efficiency (more surface area per volume).
- Allows for more compact tower design.
- Generally lower pumping head.
- Disadvantages:
- Prone to fouling and scaling (small passages clog easily).
- Higher air-side pressure drop.
- Can be damaged by improper cleaning.
- Typical Use: Most common in modern towers for clean water applications (HVAC, power plants, refineries with good water treatment).
3. Hybrid / Trickle Fill
Mechanism: Combines features of both splash and film fill. Upper section may be splash for water
- distribution, lower section is film for efficient heat transfer.
- Purpose: Balances fouling resistance with high efficiency.