In recent years, a new family of coolants has been introduced to the industry called Extended Life Coolants (ELC), or Long-Life Coolants (LLC). These fluids were developed for use in heavy equipment diesel engines, such as payloaders, bulldozers and other over-the-road vehicles.

Using ELC or LLC products in your gas compressor system can lead to hard-to-remove buildup in your equipment, reduced heat transfer and frequent system changes.

Why? These products were designed for aluminum parts in diesel engines, and they contain a low level of silicate inhibitor to protect the surface of the aluminum. When used in a gas compressor system, the silicate coating can react with the glycol coolant to form a silicate gel. The gel reduces heat transfer and builds up over time. A silicate scale can even form from low flow rates if the fluid isn’t replaced regularly, and the system cleaned. This scale further reduces heat transfer and is extremely hard to remove, leading to costly down time. If not addressed, the buildup can cause the system to overheat and the engine to fail.

Consider the following example when comparing heat transfer loss:

A 1-inch-thick piece of steel with 1/16-inch-thick silicate scale buildup (the width of most business cards) has the same heat transfer characteristics of a 4-inch piece of steel. That is to say that your heat transfer is 4 times less efficient – a significant loss with just a small level of buildup.

Industrial heat transfer fluids like AMBITROL™ and NORKOOL™ SLH do not contain silicates. The specially designed inhibitor package in these products works by reacting directly with the metal surface, meaning no additional thickness on the metal. The inhibitors are fully compatible with glycol, and if properly maintained Dow heat transfer fluids can offer twenty years or more of effective service. Dow’s analytical services are available to recommend the correct inhibitor if your system drops below the protective level and can be added without shutting down the system or replacing the coolant.

As the temperature drops and winter sets in, it’s critical to check the glycol concentration in your system. This is an important measurement to ensure freeze protection.

Coolant suppliers typically provide established minimum and maximum concentrations to help optimize performance, including protecting against freeze. Those for NORKOOL™ and AMBITROL™ Industrial Coolants can be found here.

Before winter months, it’s important to confirm the concentration and associated freeze point of your coolant is adequate for your location. The freeze point should not be higher than your region’s low temperature. Glycol concentration and freeze point can be measured with a handheld refractometer or on a coolant analysis from Dow. You can also refer to the chart included in the NORKOOL and AMBITROL Engineering Guides for a complete list of concentration and associated freeze points.

In the instance your concentration is too low, or freeze point is higher than your region’s low temperature, the recommendation is to increase concentration by adding glycol to the system. However, operators need to keep in mind freeze protection is reduced when glycol concentrations exceed 70 percent.

Freeze point refers to the temperature the first ice crystal forms. The burst point, a much lower temperature, is the point the fluid will expand and cause piping to burst. Confirming your coolant is at the appropriate concentration to protect against freezing will mean little concern about pipes bursting, even if your location shuts down during cold winter months.