Download HVAC Duct Size Calculator Excel - Free Ductulator. Duct Sizer ( Ductulator) for HVAC air ducts. It is available in SI and British IP units. For professional reports, use this electronic psychrometric chart tool. Click to download this program to your PC. These charts focus on the range of temperatures most suitable for comfort-cooling HVAC applications, and include the Trane coil curves, which depict the condition of the air leaving a cooling coil.
Duct Sizing by Hand vs. Ductulator
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Duct Sizing by Hand vs. Ductulator
Hello,
I have been forced to calculate some ductwork pressure drop by hand and ran into some inconsistancies. For a given rectangular duct size on a Ductulator, the velocity doesn't match up with what you would typically calculate as an average duct velocity. ASHRAE Fundamentals even states that the average velocity in a duct is Flow over Area, but the Ductulator doesn't seem to support this.
For example:
64' x 60' duct, 100,000 CFM
The Ductulator shows a velocity over 4000 FPM. Hand calculation shows an average velocity of 3750 FPM. This velocity affects your Reynolds number, and from there the friction factor and from there the pressure drop. This velocity also affects your calculated velocity pressure.
Can anyone out there straighten this out for me?
Thanks.
I have been forced to calculate some ductwork pressure drop by hand and ran into some inconsistancies. For a given rectangular duct size on a Ductulator, the velocity doesn't match up with what you would typically calculate as an average duct velocity. ASHRAE Fundamentals even states that the average velocity in a duct is Flow over Area, but the Ductulator doesn't seem to support this.
For example:
64' x 60' duct, 100,000 CFM
The Ductulator shows a velocity over 4000 FPM. Hand calculation shows an average velocity of 3750 FPM. This velocity affects your Reynolds number, and from there the friction factor and from there the pressure drop. This velocity also affects your calculated velocity pressure.
Can anyone out there straighten this out for me?
Thanks.