Re: HVAC questions

[Bob LaMontagne <rlamont@POSTOFFICE.PROVIDENCE.EDU>]

cliff parker wrote:

> I was speaking with my brother who is a mechanical engineer working w=
> ith HVAC design in large buildings.  As we discussed some of the phys=
> ics involved with his work he told me that one of the factors that mu=
> st be considered when designing ventilation systems is that humid air=
>  tends to rise to the ceiling.  As I pondered why this may be a few q=
> uestions came to mind that I am having difficulty answering on my own=
> .  The first comes directly from the conversation with my brother. =
> =20
>
> 1) Why should humid air in a building tend to rise to the ceiling?  T=
> he thought that comes to my mind is that the source of humidity is ge=
> nerally people breathing hot air.  Hot air rises and therefor the hum=
> idity goes along for the ride.  However, I am not satisfied with this=
>  answer because it would seem that the air breathed from people would=
>  mix with the room air too quickly to cause much convection movement.=
>   Is there more that I am missing.  It seems like there must be.

Moist air is less dense than dry air at the same temperture.

Bob at PC

This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.