Chiller Water Chemical

Chiller Water Chemical

 

 

For a Chiller Plant, especially in commercial or industrial HVAC systems, chemical treatment is crucial to protect the chiller system from corrosion, scaling, fouling, and microbial growth.

Here's a typical chemical treatment program for a chiller water system (especially closed loop chilled water circuit and open loop cooling tower circuit):

1. Chilled Water Circuit (Closed Loop)

Recommended Chemicals:

Corrosion Inhibitor:
Example: Sodium Nitrite-based or Molybdate-based inhibitor
Purpose: Protect steel, copper, and aluminum from corrosion
Dosage: 500–1500 ppm active nitrite (depends on system volume)

Biocide (Optional for closed loop):
Non-oxidizing biocides like Isothiazolinone or Glutaraldehyde
Purpose: Control bacterial growth
Frequency: Weekly or bi-weekly slug dose

pH Adjuster (if required):
Maintain pH 8.0–9.0
Chemicals: Sodium hydroxide (increase), Sulfamic acid (decrease)

2. Condenser Water Circuit (Open Loop with Cooling Tower)

Recommended Chemicals:

Scale Inhibitor / Antiscalant:
Phosphonate-based blends (e.g., HEDP + polymers)
Purpose: Prevent calcium and magnesium scaling

Corrosion Inhibitor:
Blended with antiscalant or dosed separately
Contains: Phosphates, Zinc, Molybdate

Biocide (Primary & Secondary):

Oxidizing biocide: Sodium hypochlorite or bromine tablets

Non-Oxidizing biocide: Glutaraldehyde, Isothiazolinone, DBNPA
Frequency: Alternating weekly to prevent bacterial resistance

Dispersant:
Acrylic polymer-based
Purpose: Prevents biofilm, sludge, and suspended solids buildup

Typical Targets:

pH: 7.5 – 8.5

Conductivity: As per water source and cycles of concentration

Chlorine residual (cooling water): 0.5 – 1.0 ppm

Nitrite (closed loop): 800 – 1500 ppm

LSI (Langelier Saturation Index): Slightly negative or balanced

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