[Hai-users] Temperature & Humidity sensor (fwd)

[Dan Barclay]

While using enthalpy may be a help, it's certainly not necessary.  You're
looking at how someone "feels".

A simple tweak of temperature based on humidity (or one of the other "feel
sensitive" parameters like air velocity) will do the same thing for you,
though not as elegant.  The simple table you refer to is an example of this.
Bump 'er down a bit when it's wet, bump 'er up when it's dry<g>.

Some homes (or offices) can also benefit by accounting for radiant heat from
outside walls and windows if the insulation value isn't what it should be,
and a number of other things.

There are about 3 zillion possible variables (give or take a dozen)
affecting comfort so I wouldn't get toooo scientific about just one of them.

Dan

> -----Original Message-----
> From: hai-users-bounces at tssi.com [mailto:hai-users-bounces at tssi.com] On
> Behalf Of Mike Nolan
> Sent: Tuesday, November 01, 2005 9:09 PM
> To: hai-users at romaine.tssi.com
> Subject: Re: [Hai-users] Temperature & Humidity sensor (fwd)
> 
> > If anyone has access to an ASHRAE book the enthalpy chart is in there.
> It's
> > not a simple algorithm. If you see the chart you'll know why, nothing
> linear
> > about it. However, since memory is cheap these days and with some
> > constraints on the input variables (limit the temperature and humidity
> > inputs to reasonable values) you could probably come up with a lookup
> table.
> > Would take some time but you'd only have to do it once.
> 
> I haven't done thermodynamic calculations since I was an undergrad at
> Northwestern.  :-)
> 
> I don't have the book, here's a paper that includes an enthalpy graph.
> It should be possible to pull several values directly off the table
> and interpolate enough to build a simple table.
> 
> http://ohioline.osu.edu/aex-fact/0120.html
> 
> And here's a site that you can download a humidity calculation app from.
> You will need IE with Active-X enabled:
> http://www.thunderscientific.com/web_humicalc/index.php
> --
> Mike Nolan
> 
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