Irascible - Computers & A/C

[joeyjoey]

Not really a question - just a comment.

Irascible mentioned in another thread possible effect computers might have on a/c. Before coming to this website, I never would have thought that your avg PC sitting in a corner of a room could put much of a load on a house a/c but I have to admit whenever the PC is on, the room seems a good bit warmer than other rooms on that floor

[mark beiser]

IF that PC is a high end system with fancy vidio cards and such, it can have very high heat output.
The system I'm using right now makes a little over 1,100 BTUH when I'm playing some games that make heavy use of my vidio card, CPU and disk drive RAID array at the same time.
The heat ouput is much smaller when I'm just surfing the net and such, but still significant.

A few years back I had a system with a Celeron 300a CPU that was overclocked to >900 Mhz, ran dual Voodoo2 3d accellerators in tandum, as well as its 2d vidio card, and had a level 5 RAID array in it and 9 cooling fans. All for gaming!
It had 2 power supplies and consumed roughly 750 watts of power, thats >2,500 BTUH of heat output during heavy use.

[Irascible]

My statement had to do with a guy trying to figure out why his AC no longer cools like it use to. I believe he already had techs tell him it was OK (not sure). So I was expanding to other areas. This was the exact statement:

" Still... behavioral and environmental changes shouldn’t be discounted. Did you have a couple of mild summers during those two years? Is this one a lot worse in terms of either temperature or humidity? Do you now run computers all day when perhaps you use to shut them off? Did you chop a tree down that use to provide shade?"

Six years ago there wasn't one computer in my house. Now we have six of them. If I lived in a small place with a marginally performing AC and added six computers that ran all day I'd have major problems during hot weather. Like Mark was talking about, a lot of newer powerful computers can put out a couple hundred watts of heat when they're not even doing much.

Just one computer isn't going to affect the house that much. But as you say Joe it certainly can affect one room. Add a half dozen and you've got yourself an electric heat system. In fact, I always close my diffuser to my bedroom tight in the winter. I have so much electronics in my room that I rarely need the heat.

[wilson502]

i can attest to that. MY room gets quite warm. But the carrier 2 ton unit on our side of the house has no problem keeping our rooms somewhat cool, my dad adjusted the vents to blow more air into our rooms.

[faith]

Yep, a PC generates heat! Just visit a NOC (Network Operations Center) with thousands of rack-mounted servers that would melt down without massive cooling input. A small business operation with a dozen servers or so in a small room (typical setup) will see a delta of 10 to 15 degrees on a summer day. Many servers now have thermal cutouts to protect the equipment. Additionally servers are managed remotely thus have no CRT monitors (the BIG heat generator in the mix).

Since this is a residential forum, the good news is that the shift toward passive flat screen is a godsend both to sore eyes and over worked cooling systems. The flat screen monitors are sans the massive heat output CRT's are known for.

Do your health a favor, consider flat screen a must have... The CRT is an electron gun aimed in your face, and way too many electron's miss the phosphor screen altogether and make it through to your retinas, not good...

But then you do factor all of this into your ACCA Manual J heating/cooling loads don’t you?

[travisfl]

Originally posted by faith
The CRT is an electron gun aimed in your face, and way too many electron's miss the phosphor screen altogether and make it through to your retinas, not good...

Um, well, it is really the x-ray's generated by the impact of the electrons on the phosphor screen that you need to worry about. But all modern CRTs have leaded glass on the faceplace, so the amount of x-ray emission that gets through to you is negligible.

http://repairfaq.ece.drexel.edu/REPA...html#TVFAQ_018

[jacob perkins]

Originally posted by faith
The CRT is an electron gun aimed in your face, and way too many electron's miss the phosphor screen altogether and make it through to your retinas, not good...

But then you do factor all of this into your ACCA Manual J heating/cooling loads don’t you?

Ahhh...that explains it then.I thought these headaches were caused by too much strong coffee.


And so, if you have a 300 watt computer then it is producing 1023 btu/h? (1 watt=3.41 btu)

[jfs1138]

in older tube sets it was the high voltage rectifier tube that acted more like an X-Ray tube as a lot more power was sent through it. I wouldn't worry about x-Rays from the CRT, it doesn't put out enough power to generate much and is lead shielded.

As far as heat load, if you're running a distributed computing program or a screen saver that uses a lot of CPU you're generating a lot more heat when it's just sitting there. I stopped doing this because the AC did run more with those things on. But getting the monitor to switch off is a much better reducer of heat.

Along the same vein this is why I love compact fluorescent bulbs so much is that they make so much less heat! It cost me $100 bucks to replace the entire array of recessed lights in my kitchen with CF bulbs, but I made that back in just one month in the summer from my reduced AC and electric bill! And the kitchen is much nicer to be in now during the afternoon and while cooking.

[travisfl]

Originally posted by jfs1138
Along the same vein this is why I love compact fluorescent bulbs so much is that they make so much less heat! It cost me $100 bucks to replace the entire array of recessed lights in my kitchen with CF bulbs, but I made that back in just one month in the summer from my reduced AC and electric bill!

At 10 cents/KWh you saved 1000 KWh, or 33.3 KWh/day? You must have an awful lot of light bulbs in your kitchen.

[jfs1138]

let see, 9 recessed cans with 75 watt bulbs in them for a total of 675 watts, 90% of which would have been heat, or 607 and a half watts of heaters. Converted to CF's at a third or less of the wattage. I dont' know how to calculate BTU's

Or perhaps it had something to do with the fact that was the same month I realized that the cold air return in the attic had come completely off the furnace and I was cooling 110 degree attic air for the house... lol...

But after those things my electric bill did drop over $100 the following summer month!

[Irascible]

Originally posted by jfs1138
Or perhaps it had something to do with the fact that was the same month I realized that the cold air return in the attic had come completely off the furnace and I was cooling 110 degree attic air for the house.

You think?

[travisfl]

Originally posted by jfs1138
I dont' know how to calculate BTU's

1 watt = 3.41 BTU

Originally posted by jfs1138
Or perhaps it had something to do with the fact that was the same month I realized that the cold air return in the attic had come completely off the furnace and I was cooling 110 degree attic air for the house...

Aha. I think you've got it!