Tricky Duct Static Loss Calculation
Tricky Duct Static Loss Calculation
(OP)
I have been challenged to correct a horrible ductwork installation. I have a host of problems causing me to lose static, but the biggest is described below. I will do my best to explain. Anyone know how to calculate the friction loss in the following ductwork:
3' section of 206" x 21" vertical plenum that drops out of a 54,000 CFM AHU.
A transition from 206" x 21" to 40" x 40". This transition takes place over about 6' of vertical distance. It is a very irregular fitting. If it were piping, I would describe it as an eccentric reducer. It's not quite straight on one side, but the vast majority of the reduction takes place from one end of the long 206' run. Hope that makes sense.
The 40" x 40" duct is only about 3' long. The air dead-heads into the bottom of a 40" x 40" x 40" tee with no turning veins. Coming out the two sides of the tee, the duct expands up to 54" x 20" on one side and 84" x 42" on the other.
I am trying to calculate how much static I am losing on this crazy layout. My AHU is designed for 54,000 CFM at 3" ESP.
3' section of 206" x 21" vertical plenum that drops out of a 54,000 CFM AHU.
A transition from 206" x 21" to 40" x 40". This transition takes place over about 6' of vertical distance. It is a very irregular fitting. If it were piping, I would describe it as an eccentric reducer. It's not quite straight on one side, but the vast majority of the reduction takes place from one end of the long 206' run. Hope that makes sense.
The 40" x 40" duct is only about 3' long. The air dead-heads into the bottom of a 40" x 40" x 40" tee with no turning veins. Coming out the two sides of the tee, the duct expands up to 54" x 20" on one side and 84" x 42" on the other.
I am trying to calculate how much static I am losing on this crazy layout. My AHU is designed for 54,000 CFM at 3" ESP.





RE: Tricky Duct Static Loss Calculation
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Tricky Duct Static Loss Calculation
RE: Tricky Duct Static Loss Calculation
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Tricky Duct Static Loss Calculation
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Tricky Duct Static Loss Calculation
RE: Tricky Duct Static Loss Calculation
RE: Tricky Duct Static Loss Calculation
I calculated the max flow speed which is about 25m/s, the main losses are at the parts of tee and expansion, use a approximate part to estimate them.
If the loss is important, a CFD software can give a more precise result.
System design/optimization for Airplane Environment Control System
and Evaporating refrigerating system
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