Glycol cooled draft beer dispensing systems are typically used in commercial applications such as bars, restaurants, and stadiums.
These systems use a secondary refrigeration unit (called a power pack
or glycol chiller) to maintain draft beer at the proper temperature all the way from the walk-in cooler to the point of dispense. This is done by the power pack chilling and constantly circulating a water and a food grade anti-freeze (glycol) solution
next to the beer tubing all the way from the walk-in cooler to the point of dispense.
The tubing used is called trunk line
, or also known as python. In it the beer and coolant tubing are wrapped with a plastic moisture barrier, a foil wrap to transfer cooling, closed cell insulation, and some type of outside jacket to protect the insulation.