I was looking at a ductulator and it was from trane and is probably from the 70s i found it in my van but any ways im a little confused on how to use it the first part says friction loss per 100 feet of duct it goes from 10 to .01 how do you find friction loss? and can i use a ductulator to seehow much a certain size duct can handle?
ballane89
A duculator is used after you know how much static pressure you have to use. This is determined by the air handler/furnaces rated ESP minus all device pressure drops. Then you check the equivalent length of the duct fittings(els, take offs, boots, wyes, tees, etc), add that to the linear length to find your Total Equivalent Length(virtually no such thing as only a 100 foot duct system. You do this for both the supply and return duct and add them together. Then multiply ASP(available static pressure) times 100 and divide by the TEL, to find the friction rate to use.
EG: A 326' TEL duct system. .26X100=26, 26/326= .079" friction rate.
You can use it to see how much pressure a certain size duct will lose. However, there has to be enough pressure at the ducts beginning to move X amount of air.
EG: A 326' TEL duct system. .26X100=26, 26/326= .079" friction rate.
You can use it to see how much pressure a certain size duct will lose. However, there has to be enough pressure at the ducts beginning to move X amount of air.
ballane89 If you take it on yourself to really learn how to use your ductulator correctly you will be in the upper 1% of all the techs you run into. It's a good tool.
But another question for some of the other posters. Why does someone need an app when they already have a ductulator?
Kind of like a psychometric app when it's easier to use the chart.
Batteries don't die when using a chart or ductulator.
There are also ductulators that are based on velocity reduction rather than equal friction. Probably also for static regain. So if you are using equal friction be sure you have the right calculator.
Ductulators are easier to use in the design stage. Often a duct system can't be completely visible and it's hard to know things like how elbows were constructed ie: turning vanes, radius elbows Type duct liner etc. That's probably why some just set it to .1 and swag it.
Someone once said "I always use .1 friction rate." I asked them "What are all those other numbers for then?"
But another question for some of the other posters. Why does someone need an app when they already have a ductulator?
Kind of like a psychometric app when it's easier to use the chart.
Batteries don't die when using a chart or ductulator.
There are also ductulators that are based on velocity reduction rather than equal friction. Probably also for static regain. So if you are using equal friction be sure you have the right calculator.
Ductulators are easier to use in the design stage. Often a duct system can't be completely visible and it's hard to know things like how elbows were constructed ie: turning vanes, radius elbows Type duct liner etc. That's probably why some just set it to .1 and swag it.
Someone once said "I always use .1 friction rate." I asked them "What are all those other numbers for then?"
Your return air has approximately a 4 to 5 % increase in cfm and that's why you should use a lower friction factor. It's also easier in most cases to have the return duct size increased and this will help in the overall reduction in friction losses and increase the air flow accordingly. Thank you very much
"I would like to design the duct through McQuay ducting software . please let me know
1 , For Example paricular room 600 l/s
2, Equipment type:AHU
3,How do we calculate head loss"
You should start a new thread for a new topic.
You're going to need a lot more information than what you have provided.
"Head" loss? Do you mean HEAT loss? That's yet another topic.
1 , For Example paricular room 600 l/s
2, Equipment type:AHU
3,How do we calculate head loss"
You should start a new thread for a new topic.
You're going to need a lot more information than what you have provided.
"Head" loss? Do you mean HEAT loss? That's yet another topic.
While reading manual D the friction loss formula is pressure drop ×100/TEL.
Now I realize that is of little use because how can you have a pressure drop on duct work that doesn't exist yet?So the short bus answer they give is .20 × 100/TEL...So I get it why most guys in HVAC just settle on using .067 or .10 as their friction rate because we don't have advanced math degrees and nobody else in HVAC is stepping up with an in depth answer to the friction rate formula.
Now I realize that is of little use because how can you have a pressure drop on duct work that doesn't exist yet?So the short bus answer they give is .20 × 100/TEL...So I get it why most guys in HVAC just settle on using .067 or .10 as their friction rate because we don't have advanced math degrees and nobody else in HVAC is stepping up with an in depth answer to the friction rate formula.
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
