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

[Mike Nolan]

> 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