The Science of Heat?

this ties nicely into my per-semester complaints to CIS/library/environmental programs/these forums/etc on leaving comps on all the time

The large THRN lab has ~50 comps, 95% of them are on all the time, and there's typically less than 20 students in the lab at a given time. the computers carry the biggest impact on the temp in the room and the climate control either goes nuts trying to compensate (too cold) or gives up (too hot). also the 'windows' if you can call those tiny apertures windows, are open sometimes, which also toy with the temp

if you are still in one of the comp labs this week, i think you should shut down all the comps, since they will most likely go unused and running for the next several weeks. i did this last year, and 57 of the 60 computers in the room at the time were turned on, and i was the only one in the room

someone wrote notes on the whiteboards to keep the comps on suggesting that they will break down if they are turned off. they are probably breaking down from being on too much, having so much burning dust in the the air, and having the temps fluctuate up and down so much, as you suggest

at least the library allegedly has their comps shut down at night, and most actually get use throughout the day, but they use a 3D-accelerated screensaver, thus invoking the GPU and causing an increase in noise and heat (and electricity usage), when they should just have the screen power down

when you think about how much juice a computer sucks and how easy it is to enable some sort of energy policy on them, then all these lofty plans to make the university 'greener' it makes you wonder..

I asked Rick on your behalf (pcrepair is the place to go for answers to these sorts of questions). Here's what he had to say about heating and leaving PCs on.

1 - When the Thorn labs were built, they screwed up. The architects
original design assumed that the wires would be loose under the
raised floor, allowing air to flow freely and the A/C was designed
for that. Late in the design cycle, someone realized that teflon
insulated cable was too expensive and changed the design to use
large rectangular metal conduits for the cabling instead. (When
cables are put in ventilation spaces, they must be either teflon
insulated or in metal conduits, since PCV insulation gives off
clorine gas when it burns.)

These rectangular conduits interfered with the airflow and screwed
things up. (One A/C guy claims the controls are also incorrectly
wired, the other one claims they are wired up correctly.)

All we can do is have Pam call physical resources and all they'll
do is twiddle the thermostat a bit.

2. On why the I asked that the machines be left on:
We have observed a very high hard drive failure rate when the machines
are turned off for days and then powered up. The failure happens
during power up, with a distinct "clunketty, clunk, clunk" and sometimes
a slight smell of burning components. (It is believed that this is
related to high humidity and the theory is that condensation builds
up on the drive causing failure during power up. When the drive is on,
it stays warm enough that condensation doesn't occur. This is only a
theory, but whether or not the theory is correct, the hard drive
failures do occur. 8-10 over a few days at the end of Sept. No drive
failures since then.)

As for wearing out. Yes, anything with mechanical moving parts will
wear out. However, hard drives are rated for about 120,000 hour mtbf
(mean time between failure). That works out to about 13 years of
continuous operation. The only other moving parts in the HP systems
are the fans and, surprisingly, we have not seen a single fan failure
in 5.5 years of using these systems. (Generic PC hardware usually does
have frequent fan failures.)

Since they are always on, can't we have a Guelph Folding@Home or something... unless that is already done...

Wasted CPU cycles and all...

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"The only thing that interferes with my learning is my education." -- Albert Einstein