Flue Gas Duct Thermal Losses

[KeyLargo1324]

I am working on a large heating duct. It seems that the temperature of the air in the duct is dropping significantly in this one section of the duct. The section of the duct goes through an unheated section of a building but the duct insulated. I am looking for an equation that will tell me how much temperature should be lost in this duct over a certain length. I am trying to figure out whether there is something outside of the duct that is causing the temperature drop like air - in leakage.

 

[vpl]

Could you provide a little more information? How much is the temperature dropping? What are the temperatures in the unheated section versus the rest of the segments versus the interior of the duct? How do you know that temperature is dropping in this particular segment (i.e., where are you taking temperature measurements)

Patricia Lougheed

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

 

[zekeman]

You have to give us the temperature inside the duct,the size of the duct, the outside temperature and a description of the insulation.
And how tight are the joints, since leakage could be the problem and what does "significant" mean.