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Glycol Chilling Systems: Understanding the Basics



Glycol chillers are incredible refrigeration systems that are commonly utilized for industrial purposes. They use a type of antifreeze referred to as glycol, which is often mixed with water to lower the cooling system’s freezing point. This article will expound on all the details you need to know about glycol small industrial chillers.

The Different Types of Glycol

Glycol refers to a certain class of organic compounds that belong to the alcohol family. It’s often mixed with water and then pumped through a chilling system’s pipes to slow down the rate of freezing. This, in turn, helps in maintaining temperature consistency in your industrial application. Some glycol products also inhibit corrosion as well as bacterial growth within the system.

Glycol is available in two varieties that shouldn’t be mixed together: propylene glycol and ethylene glycol. Both types provide the same level of freeze protection and they also guard against corrosion.

Ethylene Glycol: This is a moderately toxic chemical with a sweet taste- but it can be potentially harmful when ingested. For this reason, it shouldn’t be utilized in food or potable water processing systems. And this is particularly true when leakage is a possibility. Due to its affordable cost, ethylene glycol is widely used in various industrial applications, including ice rinks and factories. Plus they can also be customized to offer specialized cooling solutions.

Propylene Glycol: Propylene glycol features a lower toxicity level and makes an incredible anti-freeze. It’s safer to handle than ethylene and can easily be disposed of. Propylene glycol is commonly utilized in the food industry as well as industrial refrigeration systems where people might come into contact with the fluid.

When used at low temperatures, propylene can become more viscous than ethylene. It’s therefore important to note that mixing different types of glycol is dangerous, as it makes the product to congeal and clog the filters in your refrigeration system. And this potentially causes problems with the fluid flow as well as heat transfer.

Type of Water to Use

Although you shouldn’t mix different types of glycol, there’s something that must be added: water. For glycol to function properly, it should be mixed with water. The type and amount of water are key factors to consider.

Each glycol chiller features its own set of manufacturer recommendations regarding the best water to use for that particular system. Though city water might be acceptable at the beginning, it isn’t advisable to use de-ionized water for so long as it could end up causing adverse effects to certain components of the chiller. At times, manufacturers recommend that the chiller uses distilled or reverse-osmosis water. So, make sure that you check with the manufacturer to see the specific needs of your refrigeration system.

The ratio of Water to Glycol

The ratio of glycol to water that your chilling system needs usually depends on the coldest temperature that’ll be attained by the glycol solution during operation. If the chilling system is used in an indoor setting, there’s no chance of freezing and the amount of glycol required would be much less than that required by a glycol chiller utilized outdoors.

If the application needs to operate at a very low temperature, it’s advisable to use a glycol mixture that’s similar to that of an outdoor system. This will go a long way in ensuring that you get the best quality out of your application and significantly improve your plant’s productivity.  

Exploring the Different Options

When choosing a cooling system, a BAT (Best Available Technologies) evaluation should be performed. This procedure entails performing a detailed examination of the system’s heat flow hence improving plant efficiency and minimizing heat rejection demands. Here are some of the most popular choices:

Cooling towers – Wet evaporative systems are often limited by the wet-bulb air temperature whereas dry systems tend to be limited by the dry-bulb air temperature. These limitations might cause your plant to operate at reduced capacity or at a lower cooling efficiency. A system’s cooling capacity can be increased by incorporating additional cooling cells or by rectifying design sizing errors.

Automation – Modern controls provide advanced ways to improve efficiency through the continuous monitoring of key system parameters and the automated Adjustment of pumps as well as fans.

Fans and pumps – Pumps, fans, and blowers might be idled or slowed down during times of favorable weather conditions. Variable Speed Drives (VSDs) are commonly used on a fan, pump, as well as blower motors since they greatly improve system efficiency at partial loads. Halving the speed of a fan or pump can significantly reduce its energy demand.

Cooling medium temperature – A cooling system’s efficiency solely depends on the temperature of the medium through which the heat is being expelled. Typically, cooler mediums are easier to transfer heat to, and less cooling medium flow is therefore required. This, in turn, reduces pumping and blowing energy demands. In most cases, the temperature of the water source will be lower than the surrounding air temperature. Thus, utilizing water-based cooling systems can be quite energy efficient.

Approach temperature –The temperature different existent between the cooled working fluid and the incoming cooling medium is referred to as the approach temperature. Smaller approach temperatures demand greater cooling capacity. So, be sure not to specify approach temperatures that are less than the required. As compared to air-cooled systems, water-cooled systems tend to have smaller approach temperatures. This is because it’s easier to vent out heat into the water than air.

Offshore cooling systems – Normally, cooling systems can be installed in offshore-based facilities. Thus, they use seawater to cool. This is because seawater is plentifully available. Plus, water in these facilities has a steady temperature.

The Bottom-Line

When it comes to refrigeration, glycol is an important ingredient. And for you to get the most out of your glycol chiller, you need to choose the right type and amount of water. Once you’ve done that go ahead and determine the required approach temperature, the heat load, and the cooling medium temperature. All these specs will help you purchase the best glycol chiller for your process.