Patent ID: 8287337

Claim:
An air curtain arrangement for a cold storage doorway, comprising: a discharge means that discharges an air stream across a doorway having a cold side and a warm side; a heater that warms the air stream; a control unit that operates the heater to maintain an air stream temperature; an air return means that receives the air discharged across the opening; and an air stream temperature sensor that provides an air stream temperature input to the control unit; wherein the control unit continuously monitors the air stream temperature, and operates the heater to maintain the air stream temperature at the greater of (1) a first temperature represented by an intersection on a psychrometric saturation chart of a warm side tangent line to a psychrometric saturation curve and a humidity ratio line based on a humidity ratio, and (2) a second temperature represented by an intersection of a cold side tangent line to the curve and the humidity ratio line, wherein the humidity ratio is predetermined based upon an intersection of the warm and cold side tangent lines to the psychrometric saturation curve on a psychrometric saturation chart.