Dock and Door System Industrial door and specialty industrial plant products, reviewed several technology options to solve its food manufacturing client’s doorway energy and maintenance challenges.
The client had already installed a high-speed, insulated rollup door that reduced -5°F freezer air emigration and 60 to 95°F summertime ambient air infiltration from the shipping door area, which is 50 feet away. Despite the high-speed door, humid ambient air still infiltrated through the top of the 12 x 12-foot doorway during its hundreds of daily cycles. The greatest concern was a freezer temperature fluctuation of 8 degrees, which is unacceptable to the client’s internal product quality, refrigeration equipment wear-and-tear and energy conservation standards.
Besides energy losses, humidity infiltration also required periodic ice removal from the ceiling-hung ammonia refrigeration system’s piping, coils, valves and controls just inside the 20,000-square-foot freezer’s doorway. The fire door roller tracks also were continually iced. Additionally, the potential for forklift accidents loomed due to icy floors near the threshold, which also required ongoing maintenance.
Options to Energy loss solutions
One option Fairborn offered was a full perimeter door that re-circulates air horizontally. At a price of more than $30,000 however, the full perimeter door was a cost-prohibitive retrofit. A more economical and equally functional option was a Dock and Door System 12 foot-wide, two-speed, 2,304-cfm Model VSB air curtain mounted above the doorway at one-fifth the cost. Like the full perimeter re circulating air door way, an air curtain is up to 80-percent efficient at separating two environments. Additionally, an air curtain and a rollup door combination–the latter which the client already had already purchased and installed–is a proven effective solution to energy losses in cold storage freezer applications.
Custom Engineering a Solution
To eliminate the need to cantilever the air curtain away from the high speed door mechanism, dock and door system recommendation was to install the air curtain vertically. Because the unit was originally designed for horizontal mounting, dock and door System engineering department modified the air discharge nozzles to produce a thinner, higher velocity air stream, so that the air curtain reaches the volume, velocity and uniformity required to seal a doorway. The modification helps minimize doorway air balance issues between adjoining rooms with significant temperature differentials that are inherent in cold storage facilities.
Most importantly, kroger is realizing an energy and maintenance cost reduction of thousands of dollars per month. Managing better environmental separation at the freezer entry has also prolonged refrigeration equipment lifecycles by cutting back on operational wear-and-tear. The cost of the project is equally impressive for the client because the payback on the air curtain is less than one year, according to dock and door system.