BTUs, Mini-Fridges, AC and the Math

sevisehda · 07-04-2003, 11:47 PM

With summer approaching and the ambient temps rising I'm contemplating getting a small AC unit for my computer room.

420W PS would use .420 KW/H so thats about 1450BTUs. So would a 1500BTU AC unit conteract the computer as a whole, or is there more 'real world variables' to take into account. I know I'd have to get a stronger unit to suck the heat from my monitor, TV, speakers, and myself. I'm just confirming the max heat output of the comp.

On a similar note some people place computers into mini-fridges. Now if I were to place the 420W comp into a fridge and the fridge wasn't at least 1500BTUs the fridge would just insulate the computer and both would over heat. Any know how to find the specs on mini-fridges

tritium · 07-05-2003, 01:03 AM

You gotta consider the delta of the system. 1500BTUs in open air is a lot different than 1500BTUs with "negative" BTUs generated by the 'fridge.

Somebody here is probably a lot better thermodynamics expert then myself, they'll be able to explain it better.

hara · 07-05-2003, 04:08 AM

How much Power does a 1500BTU airconditioner consume?

If a server room has a temperature of 15C and an outside temp of 30C and the computers dump X watts, how much does the airconditioner consume.

I'm asking this for our project.

sevisehda · 07-05-2003, 04:16 AM

Ironically just after posting this I found a similar thread at HardForums. As a read the posts I relized that a fridge-mod is very inefficent and basically the opposite of what you should do if you were gonna go spend that much time.

A fridge-mod works by cooling the air which then in turn cools the hotspots(CPU,NB,GPU) by fans or by water cooling. So your cooling air then water then the hot areas. Plus you can't go too cold or else your coolant will freeze.

My idea was to take an insulated/sealed container(old fridge) and put the guts into it. Water cool the whole system(CPU, NB, GPU, Mem, Mosfets, HDs,etc) withs pelts. Then instead of insulating the pelts insulate the tubing. This way your cooling the hottest parts directly. The 'cold' will spead ******d from the pelts. The key is having enough total pelt power to cool everything in the container. You'd have to purge the container of water vapor(easily done with some silica-gel or drop a block of dry ice in the bottom and the CO2 will displace the air). After its sealed there shouldn't be any condensation or frost because theres no water to freeze. The system will probobly stabilize subzero and can go very low because your coolant is 'hot'. The hardpart is having enough radiator to cool an entire sytem plus all those peltiers.

I'm not planning on trying this anytime soon(unless someone wishes to be a sponser). My original post was to make sure my math/idea that a computer with a 420W PS basically acted like a 1500BTU heater in my room. And that I'd need at least that much in an AC to cool my room off.

redleader · 07-05-2003, 06:57 PM

Compressor wattage is NOT cooling power. Typically a good compressor can pump 4 or 5 watts for every one you give it. Though it seems you've thought better of the idea.

Also, compressors are almost always AC.

07-04-2003, 11:47 PM	#1
sevisehda Cooling Savant Join Date: May 2003 Location: NY Posts: 234	BTUs, Mini-Fridges, AC and the Math With summer approaching and the ambient temps rising I'm contemplating getting a small AC unit for my computer room. 420W PS would use .420 KW/H so thats about 1450BTUs. So would a 1500BTU AC unit conteract the computer as a whole, or is there more 'real world variables' to take into account. I know I'd have to get a stronger unit to suck the heat from my monitor, TV, speakers, and myself. I'm just confirming the max heat output of the comp. On a similar note some people place computers into mini-fridges. Now if I were to place the 420W comp into a fridge and the fridge wasn't at least 1500BTUs the fridge would just insulate the computer and both would over heat. Any know how to find the specs on mini-fridges

07-05-2003, 04:08 AM	#3
hara Cooling Savant Join Date: Oct 2002 Location: Malta, Mediterranean Posts: 662	How much Power does a 1500BTU airconditioner consume? If a server room has a temperature of 15C and an outside temp of 30C and the computers dump X watts, how much does the airconditioner consume. I'm asking this for our project. __________________ - Every great HD crash day is the day before back-up day. - My Past System - "Better to reign in Hell than serve in Heaven." - Milton, Paradise Lost. - FMZ

07-05-2003, 01:03 AM	#2
tritium Cooling Neophyte Join Date: Apr 2003 Location: USA Posts: 1	You gotta consider the delta of the system. 1500BTUs in open air is a lot different than 1500BTUs with "negative" BTUs generated by the 'fridge. Somebody here is probably a lot better thermodynamics expert then myself, they'll be able to explain it better.

07-05-2003, 04:16 AM	#4
sevisehda Cooling Savant Join Date: May 2003 Location: NY Posts: 234	Ironically just after posting this I found a similar thread at HardForums. As a read the posts I relized that a fridge-mod is very inefficent and basically the opposite of what you should do if you were gonna go spend that much time. A fridge-mod works by cooling the air which then in turn cools the hotspots(CPU,NB,GPU) by fans or by water cooling. So your cooling air then water then the hot areas. Plus you can't go too cold or else your coolant will freeze. My idea was to take an insulated/sealed container(old fridge) and put the guts into it. Water cool the whole system(CPU, NB, GPU, Mem, Mosfets, HDs,etc) withs pelts. Then instead of insulating the pelts insulate the tubing. This way your cooling the hottest parts directly. The 'cold' will spead ******d from the pelts. The key is having enough total pelt power to cool everything in the container. You'd have to purge the container of water vapor(easily done with some silica-gel or drop a block of dry ice in the bottom and the CO2 will displace the air). After its sealed there shouldn't be any condensation or frost because theres no water to freeze. The system will probobly stabilize subzero and can go very low because your coolant is 'hot'. The hardpart is having enough radiator to cool an entire sytem plus all those peltiers. I'm not planning on trying this anytime soon(unless someone wishes to be a sponser). My original post was to make sure my math/idea that a computer with a 420W PS basically acted like a 1500BTU heater in my room. And that I'd need at least that much in an AC to cool my room off.

07-05-2003, 06:57 PM	#5
redleader Thermophile Join Date: Jun 2001 Location: The deserts of Tucson, Az Posts: 1,264	Compressor wattage is NOT cooling power. Typically a good compressor can pump 4 or 5 watts for every one you give it. Though it seems you've thought better of the idea. Also, compressors are almost always AC.

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