Re: Computer room cooling

Back when we were in Lake Forest, we put our 400s and WinDoze servers in a closet under the stairwell. And the alarm company put a reed switch on the door thereto. That was a double mistake.

Even with the door wide open, the temperature was hot enough that we called it "The Sweatbox." So instead of closing the door at night, we had to override that whole circuit when setting the alarm. Had we ever closed that door, we probably would have had a lot more failures than we did.

After one particularly painful failure, I noticed that there was a fairly large opening from the closet into the ceiling cavity, and that there was a 2' x 4' opening from the ceiling cavity into the stairwell, covered only with a couple of ceiling tiles. So I jury-rigged a plenum out of a blue tarp, leading from one opening to the other, and replaced the two ceiling tiles with 24" box-fans, running 24/7, blowing the sweatbox air into the stairwell.

When we moved to Costa Mesa, I took charge of ventilating the new computer closet. As with Lake Forest, it didn't have any exterior walls, and we didn't have the budget for the sort of air conditioner that would be of any use without them, so what we ended up with was one of those perforated steel high-security screen doors on the closet (which we dubbed, "The Cage"), and started looking for an exhaust fan that would be at least the equal of the two box-fans. We looked at bathroom exhaust fans, and laughed out loud. We ultimately ended up with a big industrial roof-mount exhaust fan, ducted to an opening in the Cage ceiling, and after the first week or so, we added a speed control, so that we can slow it down in winter, or run it full-blast in summer. And (just as I did in the Sweatbox) I hung a thermometer on the rack.

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JHHL