Chiller Chemical Water Treatment Guide

Chillers are effective at cooling in commercial environments. Chillers require chemical water treatment maintenance to perform efficiently and to prevent problems.

How do Chillers Cool Water?

Chillers are common in various commercial and industrial applications such as HVAC cooling, manufacturing machinery cooling, ice rink cooling, and much more. Water and glycol are used as the medium to transfer heat. Chillers utilize refrigerant, a commonly utilized chemical that is able to transfer heat. The refrigerant in the chiller will change from liquid to gas, or from gas to liquid. Inside a chiller, water or glycol enters the evaporator heating the refrigerant. Then the refrigerant boils and changes from a state of liquid to a gas. This gas then moves to the compressor where it adds significant pressure. Next, the high-temperature and high-pressure refrigerant gets cooled in the condenser. In the condenser, the gas changes its state back into a liquid.  Finally, the liquid is sent to the expansion valve which reduces its pressure. The cycle then begins again as it moves into the evaporator. To keep a chiller cooling efficiently with minimal energy and water usage, a chemical water treatment program is needed. Common issues such as corrosion, scale, and bacteria fouling will cause inefficiency and damage to your chiller system without chemicals.

Necessary Chiller Chemicals

• Corrosion Inhibitor (Protective Film)- These chemicals work by forming a protective film layer on the chiller and loops to protect it from corroding. The rust-forming chemical reactions cannot occur between the water/glycol or air present in the chiller and loops. They also can work as an “oxygen scavenger,” which remove dissolved oxygen present in water. Common corrosion inhibitor film chemicals include borate, molybdate, nitrate, and silicate. If there are copper pipes in the chiller loop, Azoles are another type of protective film that is effective in preventing cathodic corrosion in loops with copper or brass.

• Scale Inhibitor- Scale inhibitor chemicals work by suspending all solid materials in water. These keep the solids from attaching to the metal surfaces of the chiller or loops and forming scale deposits. Common scale inhibitors utilized in chillers include polymers, copolymers, phosphonates, and polyphosphates. There are many products for inhibiting both scale and corrosion in one chemical mixture.

• Biocide- Biocides are utilized to kill organic organisms like bacteria and to prevent biofilm. There are two important types of bacteria to look out for, aerobic and anaerobic. It is advisable to use each kind of biocide. Oxidizing biocides include bromine/chlorine or sodium hypochlorite, which is essentially properly labeled bleach. Non-oxidizing biocides include Glutaraldehyde or Isothiazolin.

Chiller Glycol

US Ethylene Glycol Price Index Over Six Years

Glycol is an effective liquid medium of heat transfer with antifreeze properties for chiller systems. Its drawbacks include its low thermal conductivity compared to water and its price, which has increased significantly in recent years. There are two main types of glycols, ethylene and propylene. Ethylene is not food-grade and is less expensive than its counterpart. Additionally, ethylene glycol is more efficient at conducting heat. Propylene Glycol is food-safe and does not have as many regulations when it comes to flushing it. Glycols are mixed with water at different concentrations.

Water in Chiller Systems

Chillers can either have just water or a combination of water and glycol. It is important that the temperature does not reach freezing or below or it is susceptible to damage and reduced water flow if only water is used. Cheap, and highly conductive, having a higher concentration of water flowing in your chiller system does come with benefits. Not all water is the same, however. High pH, or hard water, will not be as efficient as softer water. At Chardon Labs, we have noticed how much more chemicals and flushing are required in our hard water locations such as Indianapolis, vs our soft water locations such as Newark. In chiller systems with cooling towers, more regular flushing is required to maintain water quality, the number of flushes required is significantly reduced by chemical treatment, however.

Closed Loop vs Open Loop Chiller Systems

A chiller can be utilized with a cooling tower, in an open loop. It can also be used without one, in a closed loop system. A closed loop system does not flush the water (usually for a long period of time), and it recirculates. In contrast, an open loop system has a cooling tower or water reservoir that exposes the water to the air. Open loop chiller systems require more chemicals to continually feed into the system, vs closed loops where this is mostly done initially.

Regular Chiller Maintenance with Chardon Labs

Chardon Labs offers routine chemical testing and treatment services for chillers. In addition to this, we also treat the loops and cooling towers, taking care of all of the water treatment processes. We set up chemical feed pumps and controllers with remote monitoring. We select the appropriate chemicals necessary for your application, make regular adjustments based on on-site water tests, feed the chemicals at specific intervals, and then take care of the disposal of all chemical tanks. Need help? Contact Chardon Labs with a short contact form or call (380) 224-7395. Either way, we will get in touch with one of our expert local service managers.

Matt Welsh

Matt Welsh is the Vice President and Water Consultant at Chardon Labs. He helps consult a wide range of customers utilizing various methods of water treatment, from chemical to chemical-free approaches, large and small applications, and across a wide range of geographical influences. With 20 years of water treatment experience, including a wide range of troubleshooting and service in potable water and non-potable HVAC and industrial applications, he is an expert in water treatment chemistry for cooling towers, boilers, and closed-loop systems.