Guide Of Cooling Tower Water Filter System

A cooling tower water filter system is used to remove suspended solids, debris, and biological matter from circulating water, protecting fill, spray nozzles, heat exchangers, and pumps while improving overall tower efficiency and water quality.

Below is a clear, industry-practical guide focused on HVAC and industrial cooling towers.

1. Why a Cooling Tower Needs a Water Filter

Without filtration, cooling tower water typically contains:

* Dust, sand, pollen

* ale particles

* Rust & corrosion products

* Biological debris (algae, slime)

Problems without filtration

❌ Nozzle clogging

❌ Fill fouling

❌ Reduced heat transfer

❌ Higher chemical consumption

❌ Increased blowdown & water loss

2. Common Cooling Tower Water Filter System Types

2.1 Side-Stream (Slip-Stream) Filter  ⭐ Most Common

Filters 5–15% of circulating water continuously.

Types

* Sand filter

* Multimedia filter

* Disc filter

* Screen filter

Advantages

✔ Low cost

✔ Easy retrofit

✔ Continuous cleaning of system

Typical filtration range: 10–50 microns

2.2 Full-Flow Filter

Filters 100% of circulating water.

Applications

* Critical process cooling

* High fouling environments

Advantages

✔ Maximum protection

✘ High capital cost

✘ Larger pressure drop

2.3 Basin Sweeper System

Targets debris that settles in the cold water basin.

Features

* Uses filtered water jets

* Pushes solids to drain or filter

* Often combined with side-stream filters

2.4 Hydrocyclone (Centrifugal Separator)

Removes heavy particles like sand and grit.

Advantages

✔ No moving parts

✔ Low maintenance

✘ Ineffective for light organics

3. Cooling Tower Water Filter System Media Options

Media Type	Best For	Micron Range
Sand / Multimedia	General solids	10–40 µm
Disc filters	Fine filtration	5–20 µm
Screen filters	Large debris	50–200 µm
Cartridge filters	Polishing	1–10 µm

4. Cooling Tower Water Filter System Design Parameters

4.1 Flow Rate

* Side-stream flow: 5–15% of circulation flow

* Basin sweepers: 3–5%

4.2 Pressure Drop

* Clean filter: 0.3–0.7 bar

* Dirty filter: ≤ 1.5 bar

4.3 Filtration Rating

* HVAC towers: 25–50 µm

* Industrial/process towers: 5–25 µm

5. Typical Cooling Tower Water Filter System Layout

Cooling Tower Basin

       ↓

Circulation Pump

       ↓

Side-Stream Takeoff (5–15%)

       ↓

Filter System

       ↓

Return to Basin / Make-up Line

6. Materials & Construction Of Cooling Tower Water Filter System

Component	Material
Filter housing	Carbon steel / FRP / SS
Piping	PVC / HDG / SS
Valves	PVC / brass / SS

Choose materials based on water chemistry & corrosion level.

7. Automation & Controls Of Cooling Tower Water Filter System

* Differential pressure switch

* Automatic backwash valve

* Timer-based backwash

* Integration with chemical dosing system

8. Maintenance Requirements Of Cooling Tower Water Filter System

Filter Type	Maintenance
Sand filter	Media change every 2–5 years
Disc filter	Periodic disc cleaning
Screen filter	Manual or auto flushing
Hydrocyclone	Occasional purge

9. Common Problems & Solutions Of Cooling Tower Water Filter System

Issue	Cause	Solution
Frequent nozzle cloggin	Undersized filter	Reduce micron rating
High blowdown	High TSS	Increase side-stream flow
High pressure drop	Dirty media	Backwash or clean
Algae growth	Poor filtration	Add basin sweeper

10. Selection Guidelines (Quick) For Cooling Tower Water Filter System

✔ Choose side-stream filtration for most towers

✔ Select 25 µm for HVAC, 10 µm for industrial

✔ Ensure automatic backwash

✔ Combine with proper water treatment