RE: [OT] Help with power usage calculation

["Andy Laurence" <andy@xxxxxxxxxxxxxxxxxx>]

Jim Noble <mailto:yahoo-groups@xxxxxxx>
scribbled on 17 March
2005 10:48:
> David Irwin wrote:
>>> I suspect your bill is in kWh. Multiply the power consumption
of
>>> your appliances by time to get the same units (ie 150W for an
hour
>>> is 0.15kWh).
>>>
>> Just as a little more clarification 1kW/h means:
>> 1 kilo      Watt                  /hour
>> 1 Thousand  (Units of Power)      per hour
>
>
> 1kW/h is a useless metric.
>
> 1 Watt == 1 joule per second.
> 1 kW == 1000 joules per second.
> 1 kW/h == 1000 joules per second per hour ... huh? (1 over time
> squared is an acceleration, not a speed or rate).
>
> If something consumes 1kW/h, don't leave it plugged in for very
> long... ;-)

It's 1 kWh, not 1 kW/h that the leccy board use.  That means it's 1000
joules per second * hour, so it's equivalent to joules, not the
acceleration of power consumption.  It's a measure of the amount of
energy used.

>> So for a 150W device used for 1 hour it will consume 150W/h or
>> 0.15kW/h
>
> 150W for 1 hour is 150Wh or 0.15kWh...
>
> A small point, but might as well get it correct...

Exactly.

Cheers,
Andy
--
http://www.andylaurence.co.uk