re: natural ventilation
30 apr 2002
>when we lived in sc, the oldtimer across the street told me that the
>humidity gets into your upholstered pcs and carpeting...
i've never seen an upholstered pc, altho my woodcarver-engineer friend
joe and i once built a tactile-matrix display/controller for dyslexia
research, with a hand-carved walnut front panel and a french polish.
these were not part of the customer's specification :-)
>and that it takes energy to pull it out; therefore, once you start your
>a/c for the season, close up your windows and after the first month,
>when the moisture is removed, your bill will be lower.
that sounds like "moisture" vs "humidity," ie condensed liquid water vs
water vapor. poor ventilation management. warm moist outdoor air can enter
a house and condense lots of water on house surfaces with temperatures
below the dew point of the outdoor air, eg a concrete floor under a rug.
the water vapor content of air (humidity) seldom exceeds 2% by weight.
reducing the rh of a 32'x32'x16' houseful of 70 f air at 80% rh with
1.27% water vapor to 70 f air with 60% rh and 0.95% vapor requires about
32x32x16x0.075(0.0127-0.0095)1000 = 3967 btu of cooling, 48 minutes with
a 5000 btu/h window ac under ideal conditions, as a one-time thing.
>...i always kept my house at about 90 in summer, and mostly ran
>a dehumidifier, so my a/c didn't come on all that much...
very stoic. you mighta been better off using the ac for dehumification,
since that dumps the latent heat outdoors.