The Efficiency of Increasing Heated Air Curtain Air Stream

Air curtain applications that were barely imaginable 10 years ago are being created as a result of a deluge of recent technological advancements.

From more efficient electric heaters to manufacturing improvements advancements have ranged that now extend lengths up to 16 feet. Earlier the air curtains with explosion and spark-proof components for hazardous industrial locations. Now they are standardized catalog items. Once, for industrial shipping doors these were energy-saving devices. Now air curtains for restaurants are also available. These are embraced by hotels, retailers, food service operators as tools for saving energy, eliminating flying insect infiltration, and increasing employee air comfort.

To separate indoor and outdoor environments the air curtains are typically mounted inside the top of a doorway, continually discharging a steady stream of air down to the threshold. From infiltrating an open doorway during winter or summer, the air stream keeps unwanted cold or hot air,respectively. For employees,they also keep out flying insects and maintain a comfortable working environment.

The Venturi style: The Venturi style heater is one of the new technological advancements. For decades air doors have offered electric heating coil options; however, the laminar flow is disrupted by their traditional mounting in the air stream, that’s critical to its efficacy. Air stream efficiency can be cut down up to 40 percent with such an obstructing placement. Furthermore, air curtain’s all-important volume, velocity, and uniformity (VVU), which is critical for maintaining an air seal across the entire doorway for ultimate efficacy is disrupted by electric heater placements in the air stream.

Besides in the discharge air, at the inlet screen where air is drawn into the air curtain, electric heaters have also been mounted. As the air curtain enclosure itself becomes heated, it’s less energy-efficient, while this positioning doesn’t affect discharge. Radiated through the cabinet that doesn’t reach the targeted area, this causes up to a wasteful 5 percent heat loss.

Essentially, the heating element is on the incoming side versus the discharge end of the fan/blower. Electrically-heated air doors with no discharge obstruction, is result of the Venturi effect heater. Thus nearly 100 percent of the airstream’s aerodynamic potential is achieved by the air curtains.