On Sun, Aug 19, 2012 at 12:19 PM, Tom Knox <act...@hotmail.com> wrote:
> > Hi Ed; > I may not have had enough coffee yet, but if Volt X Amps = Watts why would > there be a difference? That relationship holds for DC but with AC the phase relationship between voltage and current depends of the complex impedance of the load. If the load is reactive the phase will not be exactly 90 degrees. When we do the math inour heads most of us always simplify and don't bother with complex numbers but in real life impedance is complex. But for simple back of envelope calculations we can pretend the power is DC and just say Volt X Amps = Watts Another simple way to know if your PC is going to cost you an arm and a leg to run 24x7 is to place your hand over the cooling fan exhaust vent if hot air is coming out you can know for sure that you are paying $$$ to heat that air Even if the PC consumes only 50W that works out to 438 KWH per year at 20 cents per KWH you can still pay for a new $100 Atom motherboard with the savings in power and see a profit 2 years. If gets worse in the summer if you need to run the AC. Let's say the PC burns 1W. That dumps 1W of heat into the building and if your air conditioning runs on a thermostat it will burn a little over 1W to remove the extra heat. The AC is a multiplier of the power used in the house. Using this logic someone at work figured out it was cost effective to trash very old CRT monitor in the building. Same for the light bulbs, we pay a lot to cool the lighting load. (I would have simply installed windows that open and saved even more money.) -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.