Coil Bypass Factor Formula
Coil Bypass Factor: How much of the air is going through a coil unaffected?
Coil Bypass Factor=((Leaving Air Dry Bulb -Effective Coil Temperature))/((Entering Air Dry Bulb -Effective Coil Temperature) )
Example: Supply air is 60° DB, return air is 80° DB and the effective coil temperature (ECT) (Also called Apparatus Dew Point Temperature (ADP) is 47.5°F as either measured with a thermometer or plotted on the psychrometric chart.
Step 1: Coil Bypass Factor=((LA DB -ECT))/((EA DB -ECT) )
Step 2: Coil Bypass Factor=((60°F -47.5°F))/((80°F -47.5°F) )
Step 3: Coil Bypass Factor=(12.5°F)/(32.5°F)
Step 4: Coil Bypass Factor= .384 or 38% of the air moving across the coil is unaffected.