Best Water Treatment Methods for Chiller Systems

Commercial buildings, industrial plants, hospitals, data centers and HVAC rely on chillers to keep things cool. When left untreated, chiller systems can experience scaling, corrosion, biological fouling and inefficient heat exchange. These issues drive up energy costs, maintenance budgets and equipment downtime.

Treating water correctly can prolong equipment life, improve cooling efficiency and stabilize system operation. In this article we review ideal water treatment methods for chillers and how they boost HVAC efficiency.

Common Water Problems in Chiller Systems

Scaling
Calcium, magnesium and other minerals found in hard water develop scale build-up on heat transfer surfaces. Scale deposits increase energy costs and decrease thermal efficiency.

Corrosion
Dissolved oxygen, pH and chemical imbalances can lead to corrosion on steel, copper and aluminum surfaces. Equipment lifespan is reduced when corrosion causes leaks or system failure.

Biological Fouling
Cooling towers, open loops, and piping are susceptible to bacteria, algae and biofilm. Biological contamination clogs pipelines and inhibits cooling capacity.

Suspended Solids
Dust, rust, sand and sludge that collect inside the system hinder water flow and damage equipment.

Best Water Treatment Methods for Chiller Systems

1. Chemical Treatment

Chemical treatment can be one of the most commonly used treatment processes for HVAC chillers. Specific chemicals are used to help manage scale, corrosion, and biological growth.

Typical chemicals used are:

Corrosion inhibitors

Scale inhibitors

Biocides

pH adjusters

Dispersants

Chemical feed systems inject treatment chemicals directly into the water circulating system automatically.

2. Side Stream Filtration

Side stream filtration constantly removes suspended solids/debris from circulating water. Simply stated, it’s one of the best ways to keep chilled water systems clean.

Filtration equipment may include:

Sand filters

Cartridge filters

Automatic self-cleaning filters

Magnetic filters

By removing particles before they settle, side stream filtration improves system cleanliness and reduces fouling.

3. Automatic Dosing Systems

Systems can be designed to monitor the water quality and inject chemicals based on those real-time parameters. This allows for better treatment and less hands-on time.

Typical monitored parameters include:

pH level

Conductivity

Oxidation-reduction potential (ORP)

Chemical concentration

The more you automate, the more stable your water parameters will be and you will avoid over-dosing or under-dosing.

4. Deaeration and Air Separation

Air and dissolved oxygen inside chiller systems can accelerate corrosion and reduce circulation efficiency. Vacuum deaerators and microbubble air separators remove unwanted gases from the system.

This treatment method is especially important in closed-loop chilled water systems.

5. Water Softening

Water softeners can remove hardness minerals, like calcium and magnesium, before they enter the chiller system. Softened water significantly reduces scaling risk.

Ion exchange softeners are commonly used in commercial HVAC systems.

6. UV sterilization
UV sterilization uses ultraviolet light to kill bacteria, algae, and microorganisms present in the circulating water without chemicals.
UV sterilization units are commonly paired with filtration and chemical treatment for complete biological control.

Selecting Your Water Treatment Solution
Determining which water treatment solution is right for you can be based on a few factors:

System size

Open-loop or closed-loop design

Water source quality

Cooling load

Operating environment

Maintenance requirements

Filters, chemicals, deaerators, and sterilizers are often used together to provide the best efficiency for your facility. Working with a water treatment equipment expert can help you properly treat your HVAC system.

Conclusion
Proper water treatment keeps chillers systems running smoothly and efficiently. When water isn't treated properly, scaling, corrosion, biological fouling, and sludge damage can occur. Cooling tower efficiency will decrease, harming HVAC performance and equipment.
Chemical treatment, side stream filtration & automatic dosing, deaeration, water softening, UV sterilization, and continuous water analysis are some of the top water treatment methods for chillers. Utilizing these technologies can ensure your system runs more efficiently, saving money on operating costs and prolonging equipment life.
Investing in commercial grade water treatment from a professional is one of the best ways you can increase long-term performance of your industrial or commercial HVAC system.