[Greenbuilding] Passive solar in hot, humid climate / no simple answer

[Alan Abrams]

If you want to graphically analyze solar performance, I highly recommend
using Sketchup.  You can extrude a simplified model of the hosue, dial in
the latitude and azimuth, click on "shadows," and cast virtual sunshine on
your virtual house for any time of day or day of the year.

See http://greenbuilding.abramsdesignbuild.com/2006/09/post_1.php

What I've learned is that you do not necessarily design for the solstice.
In our DC area climate, we have more heating load than cooling load, so we
skew for solar gain.  We still need heat in April, but not so much in
October.  So we design for near or full solar admittance in April, even
though it means we've got heat gain in August, with similar solar angles.
We attempt to resolve this unbalance by planting deciduous trees--that leaf
out in May, and shed in October, as well as providing cross ventilation.
Other options would include vegetated trellis-overhangs, using vines that
follow the same May-October cycle.

Alan Abrams  


<<<<
Hi,

I'm planning to build a house in the Austin, Texas area, and I
want to incorporate passive solar heating and cooling into the
design.  Common wisdom around here is that a 2 foot overhang on
the south wall is enough to block the sun in the summer.