A KiloWatt is a KiloWatt...

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Externet
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A KiloWatt is a KiloWatt...

Post by Externet » Fri Sep 05, 2003 12:09 pm

Hi.
Have seen advertised several kinds of space heaters, some with special nichrome elements, some with other type of radiator plates, some with oil, some with ceramic elements...
Excepting the heat distribution effects of parabolic mirrors and built-in fans, ¿All 1 KWatt heaters will deliver exactly the same amount of heat to the same room, right?
In other words, no matter what the 'technology' claims or brand of a heater be, all 1KW heaters will heat the same, right ?<p>Miguel
- Abolish the deciBel ! -

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Re: A KiloWatt is a KiloWatt...

Post by chessman » Fri Sep 05, 2003 12:16 pm

I disagree.<p>It seems logical that efficiency would come into play, just the same as it does in DC power supplies.

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Re: A KiloWatt is a KiloWatt...

Post by Euticus » Fri Sep 05, 2003 1:24 pm

Does 1KW mean 1KW of heat produced, or 1KW of power consumed to produce heat? It probably refers to power consumption, so some units will probably convert the power to heat more efficiently. Also, some may be more effecient in distributing the heat around the area you wish to heat.

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Re: A KiloWatt is a KiloWatt...

Post by Externet » Fri Sep 05, 2003 3:38 pm

Hi Euticus.
Does not matter if 'production or consumption' but there must be no RF or other energy created exiting trough the room boundaries.<p>And as said above, no considerations for means of distributing the heat as fans or concentrators. That would only speed up the raise of temperature in certain zones, but would not affect the AMOUNT of heat delivered.<p>I am not trying to choose any brand, just to confirm they ALL must perform the same, no matter if it is a "1KW $800 Elite Atomic Mark IV compact ceramic superheater" or a "1KW $1 1920's refurbished poorman's warmer"<p>-It's about the unscientific ripoffs-
Miguel
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Re: A KiloWatt is a KiloWatt...

Post by Ron H » Fri Sep 05, 2003 4:16 pm

Dissipated power is radiated as electromagetic energy at various wavelengths. If we're talking about heating an enclosed space, my understanding is that any energy that doesn't leave the room - including visible light - is ultimately converted to heat (infrared), even if doesn't start out as infrared energy. Light absorbed by a surface will be re-radiated as heat (witness solar collectors). Any electromagnetic energy that escapes, such as light through a window, will not heat the room. So, for a simple heater to be really efficient, it seems that all it needs to do is not produce much light.
As we all know, you have to jump through hoops to produce electromagnetic energy at lower frequencies (radio frequencies). I don't think we have to worry about a simple resistive heater producing such frequencies, which could, of course, escape through the walls and ceiling.

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Re: A KiloWatt is a KiloWatt...

Post by haklesup » Fri Sep 05, 2003 4:46 pm

Since energy lost to inefficiency in circuits is usually lost as heat, it follows that any heater will convert all of its power into heat regardless of the heating element. Again, I invoke the law of conservation of energy.<p>Some small differences due to varying power factors from elements that are more inductive rather than purely resistive may influence efficiency some but it should be negligable and not worth worrying about.<p>Efficiency does come into play with regards to how well that heat can be transferred to the air and circulated around the room (for example the fan may not be efficient). Add into that the varying manufacturing costs (for different types of heater elements)and safety considerations and you end up with a whole range of features and prices.<p>Choose your heater for appearance, reliability and safety and quietness. Only worry about the wattage when you decide if it is big enough to heat the space you plan.<p>If the heater were oil or gas fired, then the efficiency of the energy conversion would become a factor as well as waste heat lost as flu gasses.<p>Power ratings posted near the power cord are for consumption but those on the packaging or advertizing are most likly for heat output, unless rated in BTU. For electric appliances, they should be the same but for any other energy source there would be losses.<p>Chris

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Re: A KiloWatt is a KiloWatt...

Post by Chris Smith » Fri Sep 05, 2003 9:44 pm

Quartz heaters radiate and re raidiate better than most. They convert watts to IR better than metal element and most other types of heaters.

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Re: A KiloWatt is a KiloWatt...

Post by MrAl » Sat Sep 06, 2003 2:27 am

Hello there,<p>The most efficient device is the space heater :-)
This is because it gets to take advantage
of what causes other circuits to have low
efficiency ratings: energy lost as heat!<p>An ordinary light bulb that is designed to
emit light energy looses about 98% of the
energy input as heat. This means even the
simple light bulb is a great space heater!
If we rate the bulb for light output, it's only
about 2% efficient, but if we rate it for
heat output (used as a space heater) we can
rate it at 98 percent, which is very very good.
How much better then is the same basic kind of
element underdriven so that it doesnt emit
as much light?
The light output from a standard heating element
is probably less then 1 percent, so the space
heater is a very efficient device.
It's hard to find that kind of eff anywhere else.<p>There are space heaters that also make use
of reflectors to DIRECT the heat in a given
direction (like straight at you) but they
arent really more efficient. They might happen
to work better if you arent trying to heat the
whole room because the heat will travel in the
chosen direction, so it could work better than
a heater that allows it's heat to spread out
more in some cases.<p>If there is any difference in efficiencies
between different makes of heaters, it's
going to be less then one percent so it's
going to be very hard to notice.<p>Take care,
Al
LEDs vs Bulbs, LEDs are winning.

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Re: A KiloWatt is a KiloWatt...

Post by Bernius1 » Sat Sep 06, 2003 8:25 am

You'll notice that most 'milkhouse' room heaters are 115V , 15A , and produce about 5100 BTU. That's all you'll get for your 1725 watts. Maybe a super-efficient heater will net 5200BTU, but (Energy Out)=(Energy In)-(consumption losses). FYI, electric heat is mathematically efficient, but still rather impractical.
Can't we end all posts with a comical quip?

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Re: A KiloWatt is a KiloWatt...

Post by desterline » Sat Sep 06, 2003 10:51 am

"electric heat is mathematically efficient, but still rather impractical. "<p>
Ha! Ha!!<p>I live in a an electricly heated apartment. In fact this entire complex is electricly heated. Electric stove's and water heaters too.<p>The difference between my fall electric bill (no heat or air conditioning) and my february heat bill is less than $30.<p>Electric heat here costs about $100 per year.<p>Compare that to the higher initail costs of gas or oil, and for me at least, electric heat is VERY practical.<p>-Denny

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Re: A KiloWatt is a KiloWatt...

Post by Gary » Mon Sep 08, 2003 12:40 am

Waste energy from an electric heater is heat, so they are essentially 100% effecient.<p>I like the "oil heater" type of portable electric heater. It is totally quiet, starts a little slowly but heats as well as any other, and has no glowing parts and is difficult to burn yourself on it.<p>Looks like an old fashioned radiator on casters, is filled with oil, and uses an electric water heater type heating element or two. Some have timers built-in to shut them off when not needed. I added a pilot light to one that lights when the element is running. I like to watch the light go on and off and know its working.

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Re: A KiloWatt is a KiloWatt...

Post by josmith » Tue Sep 09, 2003 4:29 pm

The only electric heater that is more than 100% efficient is a heat pump. Since "cold" air has almost as much heat in it than "warm" air the pump just moves it to where it will do more good.

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