Re: Temperature

DeLong, Eric wrote:

I never understood how those portable units could help..... A/C works by capturing heat from
the air in the location being cooled, then transporting that heat to

another location where

that energy can be released. If the front side of the unit blows cold air, then the back side
must be blowing hot air. Once the unit is in a room, it seems like the net effect will just
be to increase the overall ambient temperature of the room (the unit itself adds heat as it
operates).... I guess you could leave it in the doorway, but that might cause its own
problems....

You're exactly right. The best that could possibly be accomplished, unless you pipe the waste heat somewhere else (or the cool air into whatever it is you're trying to cool, is to create a bubble of cool air around the front of the unit.

In terms of generally cooling a room without piping any waste heat elsewhere, you'd be better off with a swamp cooler. Assuming it's not already too humid for such a unit to be effective.

When we were in our old building, we put our computers into a closet under a stairwell, with no connection to the outside. Even though we quickly realized that the door had to be left open at all times (and even then, it was a sweatbox), just leaving the door open wasn't enough to keep us from frying a hard drive (maybe more than one). I improvised: there was an opening at the top of the closet, leading into the ceiling cavity, and in the stairwell itself, there was another such opening, covered by two ceiling tiles. I cobbled together an air plenum connecting the two openings (and isolating them from the rest of the ceiling cavity), and mounted 2 24" box-fans where the two ceiling tiles were, blowing into the stairwell 24/7. It worked, after a fashion, and kept us from frying any more hardware. It also made the computer closet a much more pleasant place to work.

When we bought our present building, we looked into exhaust fans. The office park management showed us a big box of bathroom and stove-hood fans, but none of them could move as much air as even one of the two box-fans. So we bought a roof-mounted industrial exhaust fan, and had it ducted into a ceiling grille at the top of the computer closet. Then, to provide an air inlet, we had the door of the closet replaced with a perforated-metal security screen door. It's worked for eight years so far, except for one brief period during which the exhaust fan burned out a bearing.