Power and watts

[avoid3d]

Ok guys not to be a douchenozzle for too long but:

When referring to bitcoin mining rigs and mains electricity in general:

Power is measured in: kilowatts

Energy used is measured in kilowatt hours/b]

So if I have a rig pulling 500watts, I am drawing 0.5kw

That is 1 kilowat hour every 2 hours

That is 0.5 kilowat hours per hour. which is 0.5kw

So to say kllowat hours per hour is redundant just say kilowatts, and say killowat hours when talking about energy consumed over time.

There is no such thing as killowatts / hour. What you often mean is kilowatt hours per hour. Which is the same as kilowatts

[Anillos]

A kw is 1000 Joules in one second. If these 1000 joules was spent in two seconds, the power was 0.5 kw.

A wkh is 3 600 000 joules (It's doesn't depend on time).

If a card power is 500w, it takes a kwh in two ours, 12 kwh in a day.

There is no such thing as killowatts / hour. What you often mean is kilowatt hours per hour. Which is the same as kilowatts

True. A "Kilowatts / hour" measure could be refered as a "increase of power consumption in a certain time", like acceleration, speed and space.

Of course, if someone talks about "kwh" is Kw × h, not kw / h.

[BitBlitz]

Is there a semantics merit badge?

[PatrickHarnett]

capacity is in watts or a multiple thereof, like kilowatts
energy consumed adds a time element giving kW * h

Because most measurement systems are looking for total over time (like a month or year) and consumption or supply is no consistent you get load factor and average kilowatts and total kWh. 

In AC systems there is also power factor to consider (leading or lagging voltage and current phases), so more correctly it is kVA rather than kW.

However, when referring to the more obscure measurements, it is not correct to say that such and such a measurement does not exist.  One example is cubic acres (a six dimensional value) and this is perfectly allowable (although odd) when describing volume variance.  So having kW * h^-1 may have relevance in the right context.

[DeathAndTaxes]

Thermal conductivity, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction.
Heat transfer across materials of high thermal conductivity occurs at a faster rate than across materials of low thermal conductivity. Correspondingly materials of high thermal conductivity are widely used in heat sink applications and materials of low thermal conductivity are used as thermal insulation.  Thermal conductivity of materials is temperature dependent. In general, materials become more conductive to heat as the average temperature increases.  The reciprocal of thermal conductivity is thermal resistivity.

[avoid3d]

Thermal conductivity, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction.
Heat transfer across materials of high thermal conductivity occurs at a faster rate than across materials of low thermal conductivity. Correspondingly materials of high thermal conductivity are widely used in heat sink applications and materials of low thermal conductivity are used as thermal insulation.  Thermal conductivity of materials is temperature dependent. In general, materials become more conductive to heat as the average temperature increases.  The reciprocal of thermal conductivity is thermal resistivity.

While interesting, I assume you are mocking me? Don't you like knowlege?

[PatrickHarnett]

Just for a practical application, power station ramp rates are quoted in MW per hour.  For example, a hydro power station might be rated at 3000 MW per hour.  That means a 600 MW plant can go from zero to 600 MW in 10 minutes.

So kilowatts per hour is a valid measure in this case.

[avoid3d]

Just for a practical application, power station ramp rates are quoted in MW per hour.  For example, a hydro power station might be rated at 3000 MW per hour.  That means a 600 MW plant can go from zero to 600 MW in 10 minutes.

So kilowatts per hour is a valid measure in this case.

I hadn't considered this, but of course it is obvious in hind site.

Lol you could probably differentiate one more time and figure out the plants ability to change the rate of changing the power output. If it wasn't a technical limitation it would still be true because of the latency between sensing a higher demand and issuing the new output.

So I guess kw/hour/hour is a unit too.

[PatrickHarnett]

Just for a practical application, power station ramp rates are quoted in MW per hour.  For example, a hydro power station might be rated at 3000 MW per hour.  That means a 600 MW plant can go from zero to 600 MW in 10 minutes.

So kilowatts per hour is a valid measure in this case.

I hadn't considered this, but of course it is obvious in hind site.

Lol you could probably differentiate one more time and figure out the plants ability to change the rate of changing the power output. If it wasn't a technical limitation it would still be true because of the latency between sensing a higher demand and issuing the new output.

So I guess kw/hour/hour is a unit too.

I think that becomes important when considering start-up conditions.  For instance, when you turn on an incandescent lamp, the current changes as the filliment warms up.  A * t^-2 

And picking up on the thermal conductivity post of a few days ago, at aluminium smelters, power outages are a problem because as the metal cools, it takes more energy (current) to reheat - another kw/time measure.

The short answer is probably blame the boffins - they have a measurement for everything.