Maximum Leaving Air Temperature
Maximum Leaving Air Temperature
(OP)
What is generally the maximum leaving air temperature for VAV system with ceiling diffusers? I have seen temperatures ranging from 85 to 110 degrees. What is the most commonly accepted method for lowering this temperature and achieve desired heating? Are minimum airflows generally increased until acceptable leaving air temps are achieved?
Thanks.
Thanks.





RE: Maximum Leaving Air Temperature
As for the rest, what you ask is essentially a very subjective issue: human comfort. Supply temperatures are generally governed by comfort tolerances. For instance, residential heat pumps supply air for heating on the lower scale of the numbers you cite. Often, comfort is sacrificed as the lower temperature, higher airflow causes a "drafty," cool sensation compared to higher temperature alternatives.
As long as the ratios of airflow vs. temperature are kept the same, the same heating capacity will result. However, there is a wide divergence on the sensation of comfort.
RE: Maximum Leaving Air Temperature
RE: Maximum Leaving Air Temperature
Walkes - My system is hot water reheat vav in an office environment.
I guess I am just looking for a ballpark figure/ROT. Do you generally try to stay under 90 F? This seems to be the most common.
My follow up was that if I need heat to a certain BTU but this will yield a temp of say 130F what is the most common way to lower this to around 90 and still achieve the necessary heating (ie increase the minimum airflow on the box so that the temp goes down, airflow goes up)?
RE: Maximum Leaving Air Temperature
85°F to 90°F supply should be fine. Here is a link to check for further design information.
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RE: Maximum Leaving Air Temperature
RE: Maximum Leaving Air Temperature
CME's minimum standard is one that works.
Other than that, walkes and myself are in agreement, too.