Below are descriptions for air-cooled systems designed to dispense short distances remotely from walk-in style keg coolers. Air-cooled systems are any system that uses circulating cold air to keep the beer cool in the walk-in cooler, around the beer lines, and up to the faucet – that’s about as simple as it gets. The method of forcing chilled air from the walk-in cooler to tap was the only way to chill your draft lines until the arrival of glycol. Despite its status as the O.G. when it comes to cooling, it is still a viable and less expensive option to glycol chilling for short draw draft systems. The cost of an air-cooled beer system is relatively low, making them a great starting point for most beer enthusiasts or mom-and-pop restaurant owners.

Two types are utilized - a double duct and a single duct. In both systems, cold air from the walk-in cooler is forced via a blower through the ducts to the dispense tower and then returned to the cooler. A return is critical as the air must have a continuous cold air path back to cooler. Otherwise, the cold air would not move.

How Effective is a Forced Air System?

The effectiveness of this type of system, whether it’s a single or dual duct setup, will be the refrigeration temperature. Your foodservice design company or refrigeration engineer will need to factor in the standard design criteria for a walk-in cooler, the air ducts’ length, and the heat generated from the blower. For this setup to be successful, the walk-in cooler for beer storage must maintain a consistent temperature of 34-38˚ F. The maximum recommend length for this setup is 25 ft. requiring approximately 1,000 Btu per hour of additional refrigeration capacity. The system can exceed 25 ft., but you would need to minimize the amount of 90-degree bends in the system and make sure the walk-in cooler is not frequently opened. Each 90-degree bend in the system will result in lost cooling efficiency. A walk-in keg cooler used for food storage where the door is continuously opened directly impacts air-cooled systems' performance due to air temperature fluctuations.

Key Tips:

1. Properly size the blower to deliver the proper amount of CFMs.
2. Limit the number of 90-degree bends in the air duct(s).
3. Seal all seams to reduce air leaks through the duct(s).
4. Secure all beer connections to prevent air leaks or cooling loss.
   
   

Double Duct Air Cooled System — Dispensing Up To 25 Feet

The double duct air-cooled keg beer system is defined as two ducts with a blower for continuous air circulation. One duct is for the cold air supply from the walk-in-cooler to the point of dispense. The second duct is for the cool air to return from the point of dispense to the walk-in cooler. The trunkline(s) are housed inside a larger diameter flexible tubing connected to the cooler and the beer tower at the other end. A blower fan mounted in the walk-in cooler forces cold air through the tube to the beer behind the faucet keeping the beer lines cold. This first line would be considered the supply side of the forced air loop. Once the air has reached the beer tower, it returns to the cooler through the other section of tubing called the return. The supply and return create an infinite loop of forced air to maintain the temperature of the beer trunkline(s).

Usually, the double duct system is used in conjunction with a shaft box or double pedestal draft beer tower to ensure proper air return to the walk-in cooler.

Single Duct Air Cooled System — Dispensing Up To 15 Feet

The trunkline(s) are housed inside a smaller diameter (i.e., 3″)  flexible tubing, which is contained with a larger diameter (i.e., 4″)  insulated flexible metal tubing that is connected to the cooler at one end and the beer tower. A blower fan is mounted in the walk-in cooler forces cold air through the smaller diameter tubing to the beer tower behind the faucet(s) to keep the beer lines cold. Once the cold air has reached the beer tower, it returns to the cooler through the larger diameter tubing. Usually, an air separator kit and a baffle plate are required in the draft beer tower to ensure proper air circulation. This type of system is used with a single column beer tower.