[Greenbuilding] energy and power terms

[Alan Abrams]

methinks that what is problematical is semantical.  if it is gallons of
milk that are important to a mother, and gallons of milk per hour that are
important to a milkmaid, and if these terms are logical and intuitive--then
watts should logically be the term for the volume of electricity consumed,
and watts per hours should be the term for the rate.

but it's not.  hence the confusion.

On Mon, Nov 21, 2011 at 7:06 AM, nick pine <nick at early.com> wrote:

> David Bergman writes:
>
>  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.,
>>
>
> Perhaps the intent was to say that the laborer can generate 75 watts for a
> long time, vs 300 watts for a shorter time. And accelerating a 4000 pound
> car from 0 to 60 mph takes about 1/2mV^2 = 1/2x4000x0.454lb/kg(60x0.447)^*
> *2 = 653K joules. If that happens in 6 seconds, it might require a
> constant 653K/6 = 109K joules per second, ie 109 kW for 6 seconds, or
> perhaps more power and smoke at the beginning and less at the end, at a
> non-constant rate.
>
> Nick Pyner wrote:
>
>  ... If you must use automotive terms, I submit it might be better to use
>> the fuel gauge than the speedo.
>>
>
> The rate of change of the fuel gauge is closer to power 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.
>>
>
> One horsepower is about 3/4 of a kilowatt, like 10 75-watt people.
>
> Nick
>
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