Ductwork Heat Loss or Heat Gain & Condensation Analysis[ back to full computer program list ]1. This computer program calculates the heat loss or heat gain from insulated round or rectangular ductwork. The program also checks for condensation on the inside duct surface and on the outside duct surface. The program will check for condensation at the start of the duct run and at the end of the duct run. 2. When you compare the air flow into the duct, to the air flow leaving the duct you will see the airflow (ACFM) has changed due to a change in the density of the air.. When air flows through a duct it will experience a pressure drop and a temperature change which changes the ACFM flow because of the change in air density. The mass flows (lbs/hour) are not affected by the air pressure change or the temperature change, therefore the mass flows are the same unless there is leakage. 3. Below are 2 examples one for rectangular ductwork and one for a round duct.  Example #1 - Ductwork Heat Gain & Condensation Analysis Computer Program Input Data1. Duct Size: 12" x 12"2. Insulation Type & Thickness:
Fiberglass Insulation Density 6.0 lb/ft3 3 ½ inches thick 450 F max. 3. Insulation Jacket:
Aluminum 0.016 inches thick Emissivity = 0.11 4. Air Entering The Duct:
Dry Bulb = 55 F Relative Humidity = 80 % Air Flow = 2,467.1345 ACFM Dry air Mass Flow = 11,274.4717 lbs da/hour Water Vapor Flow = 82.6950 lb w.v./hour 5. Ambient Conditions On The Outside Of The Duct:
Dry Bulb = 90 F Relative Humidity = 80 % Air Velocity = 100 ft/min 6. Ductwork:
Aluminum Duct
0.040 inches thick 50 feet long AMBIENT3.txt
Condensation Analysis of Air Flow Thru Insulated Pipe or Duct (PDF) |
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