re: how does one beat the heat?
23 jun 1998
>...things i have observed that seem to help:
> * lots of trees shading the house...
how about vines, and so on? trees high enough to make
high angle summer sun shade may also fall on the roof.
> * basements (they seem to lower the thermal mass
> of the house).
basements raise thermal mass, but they can cool if air near
the floor is brought up into the house with a fan. a slowly-moving
surface air film has a thermal conductance of about 1.5 btu/h-f-ft^2,
so a 1000 ft^2 55 f basement floor might make (75f-55f)x1.5x1000
= 30k btu/h of house cooling, like 6 window acs, for a while,
until it warms up. sprinkling some water on the floor might
keep it from warming up, or running the air through an old
car radiator with some wellwater flowing through it.
thermal mass can also help cool a house by venting at night when
outdoor air temps are lower, then buttoning up the house during
the day, and allowing its thermal mass to absorb heat. one might
add more thermal mass to the basement... a house with 2,000 ft^2
of 1/2" drywall and 2 dozen 55 gallon drums in the basement
(c = 1,000 + 10,560 btu/f) and a thermal conductance of 400 btu/h-f
in the philadelphia area might be cooled to 70 f on an average july
night, using 67.2 f outdoor air and a whole-house fan, and rise to
about 70 + 18hours(82f-70f)400/c = 77 f when the average daily max
outdoor temp is 86.1.