On Tuesday 08 March 2005 02:23, Duncan Lithgow wrote: >On Mon, 2005-03-07 at 16:27 -0800, Brian Mury wrote: >> Of course an electric heater is 100% efficient. A lightbulb is not >> 100% >> efficient - it's job is to produce light, but it has loss in the >> form of >> heat. An electric heater's job is to produce heat - and it has >> loss in the form of what? Heat? Every bit of energy consumed by an >> electric heater generates heat. All of it. Every last bit. > >Sorry Brian - I think you need to do some homework on this one. > >- Anything which gives out some light is giving out less heat. And that light, when its absorbed by a surface thats not 100% reflective becomes what? Thats right, heat. >- Anything which gives out some noise is giving out less heat (thou > this depends _marginally_ on the surface the sound hits) And the result of the sound absorbtion isn't friction which makes heat? >- A computer screen and several components convert electricity to >electro-magnetic fields Yes, with an overall circuit efficiency in terms of recovering that magnetic energy, to be put back into the next cycle, is often >90%, that just means the supply doesn't have to furnish but maybe 10% of the energy circulating in that circuit. And thats the heat dissipation. As far as its doing work that is non-heat, in the form of bending a beam of electrons as they go by. The amount of work, considering the weight of the beam and its potential mass gain from relativistic effects, are so small as to be ignorable in the string of zero's to the right of the decimal point. >- All those capacitors also loose energy - I'm not sure what it is > lost as, maybe heat - possibly chemical changes Its all heat, primarily from ESR at medium and lower frequencies, and by dielectric heating at the higher frequencies. Either way, the conversion to heat is 100%. Any chemical changes are temp related, and are accompanied by the fact that anything you put into a capacitor had better be 100% recoverable. Anything less means the capacitor is defective. >- A computers fan is actively using electricity to _cool_ space. And its 4-10 watts consumed is pumped into the passing air to keep itself cool. The air it moves may be cooler, but the heat in that box is still 100% from i2R losses. >It's never a good idea to claim anything is 100% good at anything. >Electronics and thermodynamics are a bit more complicated than at > first sight. There may be lots of intermediate stages for the energy, but at the end of the day, the end result is heat. Always. >Duncan -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) 99.34% setiathome rank, not too shabby for a WV hillbilly Yahoo.com attorneys please note, additions to this message by Gene Heskett are: Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
