[Greenbuilding] An annotated St. Louis TMY2 simulation

[nick pine]

"Doug Kalmer" <dougkalmer at gmail.com> writes re:

>... movable window insulation. I've been using mine for over 22 
>years-

Historically, most people quickly tire of moving insulation twice a 
day.

>... window technology has increased, greatly improving R-value and 
>heat retention.

Windows on living spaces without movable insulation lose heat on 
cloudy days...

Johannes Martinez <johannes.martinez at gmail.com> writes:

> Hi Nick, i wonder if there's a reason you didn't include losses 
> through the floor, is that usually negligible?

It's less than losses through walls in December, when the ground is 
warmer than the air. It's one of many refinements that can be added to 
the simulation I posted...

> Do you have a helpful resource for all the formulas you use

It's mainly Ohm's law for heatflow, I = E/R. In US units, I is in 
Btu/h, E is an F temperature difference, and R is an R-value divided 
by an area in square feet. And a thermal mass equation: Tnew = Told + 
Idt/C, where dt is a time difference in hours (1 hour in the 
simulation I posted) and I a rate of heatflow into a thermal 
capacitance C (mass) in Btu/F, eg 1 Btu/F for a pound of water or a 
board foot of drywall and 25 Btu/F for a cubic foot of concrete.

Sounds like John Straube's book (which I haven't seen) would help, or 
"Heating and Cooling of Buildings" by Kreider and Rabl or "Mechanical 
and Electrical Equipment for Buildings (MEEB)" by Stein, Reynolds, 
Grondzik, Kwok, or "Principles of HVAC," 6th Ed., Howell, Coad, and 
Sauer, ASHRAE , 2010, or any edition of the ASHRAE Handbook of 
Fundamentals, or the 2nd edition of Schaum's Heat Transfer Outline, 
for more detail and complexity.

> I'm looking to build a 3d house construction and simulator in lisp.

I used to program in something like... And APL :-) A lot of 3rd 
graders used to speak BASIC.

> I could cull some from your code, but my eyes start to go wonky 
> after staring at basic for a while, too many repressed memories of 
> typing in increasingly more difficult to comprend, obfuscated basic 
> code until it evolved into reams of hexadecimal...you know you've 
> gone to far when you can start recognizing opcodes.

Nathan Hurst wrote a Nick BASIC to Python converter to deal with my 
simulations :-)

http://njhurst.com/blog/01234664809

Nick