Power Consumption

by Administrator on August 4, 2007

How Hot is Your Hardware? How hot does your hardware run?  It’s a simple question to ask your vendor that usually provokes, at best, an unknowing shrug from your sales rep, and at worst, a mealy mouthed explanation that this depends on the architecture of your facility, your workload, etc.  

With green IT stories showing up everywhere you look, I wondered why vendors don’t just post a simple power utilization statement with their products.  That would at least allow us to estimate BTUs.  Maybe they don’t know the formula, so, to help them, I asked Margaret to Google it while I was on the road to Connecticut on Thursday and Friday.  She found this article, and this extract…

An average stereo uses 80 watts. To find out how much energy your stereo requires, look on the labels on the back. You should find a number followed by a “W.” For instance 150W would mean 150 watts. Some appliances give the energy requirement in amps (for example 1.5 A).

To convert amps to watts, multiply by 120 (1.5 amps x 120 volts = 180 watts).

Let’s say you listened to your 80 watt stereo for 2 hours. This would be 160 watt-hours.

If you divide watt-hours by 1000, you get kilowatt hours, and 3412 BTU is equivalent to one kilowatt hour.

80 watts x 2 hours = 160 watt-hours

160 watt-hours/1000 = 0.16 kilowatt-hours

0.16 kilowatt-hours x 3412 BTU/kilowatt-hour = 546 BTU

Now, just knowing power consumption in watts or amps doesn’t get us to a full understanding of additional HVAC requirements, which are a secondary consequence of power (in)efficiency.  (Unused energy shows up as heat.)  But, perhaps totalling BTUs would give a partial idea of thermal load that must be offset by HVAC plants.  But, there you begin getting into the doublespeak of storage equipment vendors about variables that effect heat generation.  (Witness this debate between Cisco and Brocade touched off by some basic measurements taken by ESG on behalf of Brocade.)

I am thinking about NOT reporting on products anymore unless the vendors begin including clear statements about power consumption in their briefings and press releases.

Previous post:

Next post: