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re: heat loss through skylight
27 dec 2005
m ransley errs again:
>today and this time of year 6 hr of radiant energy from the sun is all
>you get, if it isnt cloudy out. 18 hrs is your time frame to loose
>energy, 3 times the period of gain.
irrelevant. simple physics and real weather data say a skylight with n
glazing layers will gain 460x0.9^n btu/ft^2 and lose 24h(65-26.7)/n on
an average december day in chicago. with more physics or calculus, you
might figure dgain/dn = 0 makes n = e^(0.505n+1.47). n = 5 on the right
makes n = 5.6 on the left, then 5.77, 5.82, and 5.84, so n = 6 maximizes
the net gain, vs a ***loss*** for mere insulation.
>i still say if your numbers reflected real world weather you would see.
those numbers are nrel's 30-year measured weather data for chicago.
why not give up your excellent imitation of a nitwit? :-)
nick
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