What is the cost of energy consumption and cooling servers? (109 Views)
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Regular Advisor
Tony Williams
Posts: 174
Registered: ‎08-27-1997
Message 1 of 2 (109 Views)

What is the cost of energy consumption and cooling servers?

I'm trying to develope a spreadsheet that tracks the energy comsumption in kwh and heat dissaption in BTU/hr. I also want to assign a cost to these metrics. Computing energy consumption and cost seems easy enough:
Watts x 8760(hours in a year)/1000 gives you kWH. kWH x .10(cost per kWH) gives you the cost per year for energy consumption.

Computing the cost for heat dissapation proves to be a lot harder. I have only been able to find one formula to do this but I don't understand it.

The formula comes from http://findarticles.com/p/articles/mi_m0BRZ/is_10_23/ai_111062988. A synopsis of the article is:

We're not done with the calculators just yet. There is one other factor that we failed to take into consideration; all electrical products produce heat. Heat is called BTUs (British Thermal Units) and for every watt of power consumed, 3.41 BTUs are created. As a result, the 100TBs of RAID noted above generate approximately 136,400 BTUs per hour. The more power used, the more heat is produced, which must be compensated with cooling to prevent the products from overheating. Air conditioning systems installed on top of buildings are used to introduce cool air into the computer room to keep the temperature constant. Unfortunately, air conditioning systems use power, too, and the age and efficiency of the air conditioning system will determine how much electricity and cost necessary to keep the above storage system cool. The efficiency of an air conditioner is based on the K-Factor. High efficiency units may consume as little as .33 BTU to cool 1 BTU of Heat. Older units may have a 1:1 power to cooling ratio. Therefore the next calculation looks like this:

#BTU/3.4/1000 x .33 x .10 = Cost Or 136400/3.4/1000 x .33 x .125 = $1.32 Or 31.68 per day Or $ 11,563 per year

I don't understand why BTU's are divided by 3.4.

Does anyone know or have a formula to use to calculate the cost of heat dissaption?
Advisor
eric watson
Posts: 19
Registered: ‎08-21-2000
Message 2 of 2 (109 Views)

Re: What is the cost of energy consumption and cooling servers?

Hi Tony,

It appears they are converting the BTU's into kilowatts if I read your description correctly. For every watt of power consumed 3.41 BTU's are produced. So for every 3.41 BTU's of heat produced you consumed 1 watt of power. Then ddevide by 1000 to get KW's you end up being metered for.

Hope it helps, Eric
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