I need a questioned that I am absolutely not able to answer…
At our school, our computer teacher is all about saving the environment. He goes on and on about not wasting paper, and to do everything electronically. We also have budget issues with a limited amount of money.
At the same time, he keeps the aircon on in both computer labs 24hrs a day, 365 days a year. he keeps it at a cool 20 c degrees. he also keeps the computers on 24 hrs a day, 365 days a year. His justification for the aircon is that the computers will last longer under climate controlled conditions.
I am basically looking for a figure in both costs and destruction of the environment that i can confront him with…
How important is it to keep them cool?
How much savings would it be to keep the room at a comfortable 25 instead of 20
How much does it cost to keep 40 computers running 24 hrs a day, 365 days a year
What effect does this have on the environment, and what type of resources are depleted?
I just want as much firepower as possible next time he goes off on our teachers about the waste of paper.
Thank you
CRAC (Computer Room Air Conditioning) is a huge energy eater.
What sort of computers are these? Are we talking about servers in racks or desktop PCs?
In a server room or data center, the new way of thinking is that if the room is chilly, you’re wasting gobs of energy by cooling the room, rather than directing the cooling into the racks and servers themselves.
If it’s a bunch of desktop PCs, they do at least have LCD monitors, right? Old CRT monitors use much more power and give off much more heat than LCDs, resulting in needing more electricity to run them and cool the room.
68 degrees (20 C) is a bit colder than the computers and occupants need to be. Your figure of 25 works out to 77 degrees Fahrenheit, and that’s warmer than most people like to be at. AFAIK, most offices aim for around 72-74 degrees - about 23 C.
The days of computers needing to be at a steady and cool temperature are pretty much gone - if it’s comfortable for people, the computers will be OK.
As for power consumption, you can estimate about 150 watts to run a typical PC, and 75 for a CRT or 25 watts for an LCD. If computers with LCD monitors never go to sleep, you’re looking at 175 watts with an LCD, times 24 hours a day, or 4200 watt-hours - 4.2 kWh - each. At my current local prices for electricity, that’s close to 75 cents per day, and that’s just one computer. Your computer lab is sucking down over $1,000 a year just to run those computers, plus whatever the room cooling costs. Not exactly “carbon neutral” is it? 
thank you gotpasswords…the 40 or so computers are all new imacs.
Ah, in that case… You couldn’t have hoped for a much more power-efficient computer. The newer imacs run at about 95 watts while active, and can go to sleep at about 2 watts - not really even enough to bother counting. Even when active, they don’t put out a lot of heat, either, so they put less load on the air conditioning. And I still think the temperature is excessively low. Raising it a couple degrees will reduce the overall power costs a lot - possibly even to the point of making the computers “free” to run all day long.
One of them will cost about $140 per year to run if it’s in constant use. More likely, it’s only being used half the day, if even that often, so $70 or less per year. (Is the lab open 24 hours a day, and are all 40 being constantly used?)
I just realized I slipped a decimal earlier, and 40 standard PCs will gobble down roughly $5,000 - 10,000 in electricity per year, depending on usage.
As for what resources are being used, that depends on what your local electricity generation is using - coal, natural gas, hydro, nuclear, etc. - and to what extent they’re “renewable.” As an example, a dam and hydroelectric power uses water flow to make power, and nothing’s really consumed. Coal, on the other hand, is burned, and is definitely and irreversibly consumed.
As for what resources are being used, that depends on what your local electricity generation is using - coal, natural gas, hydro, nuclear, etc. - and to what extent they’re “renewable.” As an example, a dam and hydroelectric power uses water flow to make power, and nothing’s really consumed. Coal, on the other hand, is burned, and is definitely and irreversibly consumed.
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gotpasswords…thanks again. well, we live in japan (working at an international school), so being that most of our power is nuclear i believe…this makes me wonder how many barrels of non-biodegradable nuclear waste is being produced in order to generate the power to run the aircon, and the computers?!