[TriLUG] OT: thermodynamics of A/C question

[Steve Litt]

On Fri, 22 Jun 2012 13:25:45 -0700 (PDT), Joseph Mack NA3T said:
 
> I can either
> 
> o set the A/C to 82degF and have it run during the day 
> dumping to air at 90degF (say). Then at night the A/C 
> doesn't run much (at least in the current weather). In the 
> morning, the house is still 82degF.
> 
> o set the A/C to 76degF when I go to bed. I wake up to a 
> cold house in the morning and set the A/C back to 82. The 
> A/C doesn't run during the day (at least for today, with 
> 90degF outside).

If your house is anything like my house, then in the absence of air
conditioning or open windows, every hour it goes about half way toward
the external temperature. By 2PM it's basically as hot as the (90+, I
live in Orlando) external temperature. I don't think your house is
going to function as a heat sink long enough to have your morning
running start carry through til 6pm. Unless of course you're a lot more
insulated than my house.

If you have lots of computers, one thing you might do is, for each
computer, have all fans incoming except the power supply fan, and fit a
large hose (shop vac hose?) over the power supply fan outlet going
directly to the outside, so your computers never heat up the internal
air. Or if you really want to get tough, get the incoming air from the
outside too, although 90+ degree air might not sufficiently cool your
computer.

I don't know if your area is humid or dry, but if it's dry you can
always get an evaporative cooler. I saw one of those used with great
effect in California's San Fernando Valley, where it's dry.

SteveT

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