Russell McMahon wrote:
> This is both a request and a reference to resources:
>
> I'm looking for a set of algorithms which allow the characteristics of 
> moist air to be determined.
> Lots of people seem keen to sell me books and programs on the subject 
> and there are numerous online calculators covering the core variables.
>
> The essential algorithms which I'm after are here, courtesy of the 
> ASHRAE handbook.
> This rather messy set of algorithms will probably allow most requisite 
> calculations
>
>         http://www.ageng.ndsu.nodak.edu/envr/PsycEqns.htm
>
> Not rocket-science but annoyingly fiddly.
>
>
>
> Question: has anyone got any useful comments on the subject and/or 
> practical useful algorithms for psychrometric or hygrometric 
> calculations. These may be simplifications to or modifications of the 
> ASHRAE algorithms or distilled arcane knowledge or ... .
>
>
>         Russell
>
> ____________________________
>
> Other resources:
>
>
> Online calculators of various capabilities
>
>         http://www.sugartech.co.za/psychro/index.php
>
>         http://www.linric.com/webpsysi.htm
>
>
> Books
>
> Distressingly thick book give the title :-) - "Understand 
> Psychrometrics"
> Looks good
>
>     http://www.buildingsciencepress.com/books.asp?CatID=19
>
> Search list - hygrometry tables. For money.
>
>         http://www.worldcatlibraries.org/search?q=su%3AHygrometry+Tables.&qt=hot_subject
>
> Program $US169.
>
>         http://www.123supply.com/hdpsancdbene.html
>
> ASHRAE* Handbook.             * The 600 pound gorilla
>
>         http://www.ashrae.org/pressroom/detail/13624
>
> Psychrometric equations.
> Gargoyle says -
>
>         http://www.google.com/search?num=100&hl=en&rls=com.microsoft%3Aen-US&q=psychrometric+equations
>
>
> ________________________
>
> FWIW - The set of parameters that one usually wants to play with 
> (taken from my 1st reference above) include enthalpy, latent heat of 
> vaporization, heat of sublimation, humidity ratio, pressure, 
> saturation vapor pressure, vapor pressure, relative humidity, dry bulb 
> temperature, dewpoint temperature, wet bulb temperature, specific 
> volume, saturation humidity ratio.
>
>
>   
Russ,

These equations (in FORTRAN) are well documented,
with check values (important)!

http://wahiduddin.net/calc/density_algorithms.htm

Good comparison of "leading" vapor pressure calculations

http://cires.colorado.edu/%7Evoemel/vp.html

This one has some of the "rocket science" stuff

http://maths.ucd.ie/met/msc/PhysMet/PhysMetLectNotes/node26.html

excellent resource for all sorts of weather related physics.

here's another good place to surf around in

http://amsglossary.allenpress.com/glossary/search?id=reversible-moist-adiabatic-proc1

Let me know if you need more. Most of my links are at work.

Jim

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