[Greenbuilding] energy and power terms

[David Bergman]

In the article, the analogy they're making is that watts are a 
measure of a flow rate, vs the amount used (kWhm or, in the analogy, 
miles). Works for me.

Water flow rates, of course, are the more commonly cited analogy. So 
fuel flow could work, too (for example, 10 gallons per hour, then 
times the number of hours to get the amount), but a fuel gauge does 
not show the flow rate. A speedometer does. (The fuel gauge shows 
energy remaining, or the opposite of energy used.) And it's more 
tangible for most -- with the exception of planes (and boats?), we 
generally think of fuel flow in terms of mpg (is the metric 
equivalent kpl?), not gph.

The article also says, btw, that watts are comparable to horsepower. 
But I do find their explanation before that rather confusing: "A 
laborer working through the day will put out 75 watts of power. A 
medium-sized car might consume 100,000 watts." Those sound like 
energy totals, not flows.

David

At 06:57 PM 11/20/2011, Nick Pyner wrote:
>I don't think that's a good analogy at all, and probably just adds 
>to the confusion. If you must use automotive terms, I submit it 
>might be better to use the fuel gauge than the speedo. Or how about 
>the engine? A watt is exactly like a horsepower, just 3/4 the size, 
>and most of the world uses just that.
>
>
>Nick Pyner
>
>Dee Why   NSW
>-----Original Message-----
>From: greenbuilding-bounces at lists.bioenergylists.org 
>[mailto:greenbuilding-bounces at lists.bioenergylists.org]On Behalf Of 
>David Bergman
>Sent: Monday, 21 November 2011 7:02 AM
>
>Perhaps the best single way to think of it (per that article): 
>"Watts are like miles-per-hour."
>
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David Bergman  RA   LEED AP
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