Industrial Chillers

Glycol Chillers are a specific kind of refrigeration system, often used to cool a variety of liquids, including alcohol and other beverages. Using a chiller allows producers to lower the temperature of the product dramatically over a short period of time, depending on the production needs. Propylene glycol plays a significant role in the application of a glycol chiller. For cooling in brewing, there are few processes where decreasing or maintaining temperature are important - like crash cooling a beer after fermentation, or keeping a steady temperature during fermentation (which generates heat), or cooling the wort after an initial boiling process.

Glycol is a water-miscible coolant that is frequently used in heat transfer and cooling applications. It provides better heat transfer parameters than water, and can be mixed with water to provide a variety of heat transfer characteristics. Glycol comes in two varieties: ethylene glycol and propylene glycol. Though both materials are bad for living things, propylene glycol is most often used near food and ethylene glycol is most often used in industrial applications.

To understand the purpose of glycol, you must first understand how a chiller works. A chiller consists of two key parts: a refrigeration unit which uses electrical energy to produce a cold fluid, and heat transfer coils which move cold fluid from the refrigeration unit to the target area and hot fluid from the target area to the refrigeration unit. Typically, the target area is the inside of a freezer or some other object that you want to cool. The refrigeration unit often consists of a compressor with some compressible heat transfer fluid such as freon.

Every chiller has an operating temperature range. This temperature range is determined by several variables, the most important of which are the boiling point and freezing point of the heat transfer fluid. Glycol is prized as a heat transfer fluid because it can operate at a wide range of temperatures and can be mixed with water. The boiling and freezing points of glycol mixtures are a function of the relative amounts of glycol and water in the mixture.

Pure water freezes at 0 degrees Celsius (32 F) and pure ethylene glycol freezes at -12.9 C (8.9 F). In between, freezing points are non-linear. For instance, a solution of 10% ethylene glycol freezes at -3.4 C (25.9 F), 30% ethylene glycol freezes at -13.7 C (7.3 F) and 60% ethylene glycol freezes at -52.8 C (-63 F). The freezing point of a 60/40 ethylene glycol/water mixture is much lower than that of either pure ethylene glycol or pure water. Mixtures of propylene glycol with water follow a similar pattern, with a 60/40 mixture of propylene glycol with water having a freezing point of -48 C (-55 F).