On Thu, 09 Apr 2009 15:16:37 -0400, Ernie Willson
wrote:
stan wrote:
On Apr 9, 3:32 pm, N8N wrote:
On Apr 9, 12:17 pm, "HeyBub" wrote:
Twice as much.
"Every CFL light contains a small ac-dc power supply with reactive
components in it that will affect the CFL's power factor (PF) - that is, the
load presented to the ac line. The closer the PF is to 1, the better. A load
with low power factor (.85) draws more current and is less efficient than a
load with a high power factor for the same amount of useful power. ... These
power losses don't show up directly on our electricity bill, but the
utilities sure see the effects.
"I put one of my home CFL bulbs on my Kill-O-Watt power meter recently and
measured its power factor: It was .57. This is lousy. "
http://www.edn.com/blog/1470000147/post/450043045.html
that is pretty crappy, even old style fluorescent fixtures are
generally 0.8 or better.
Now I'm going to have to try that when I get home to satisfy my
curiosity.
nate
One reservation we have about the use of CFLs is that since we heat
most homes here with electricity (hydro generated) anyway and never
need, in this climate AC, the so-called wasted heat from cheap (25
cent) incandescents (when on at night for example) is merely an
alternative to our electric heating!
One place that CFLs do make sense is outside, where they are sometimes
left on at night for safety and insurance reasons. But CFLs in very
cold climates do not seem to be always the best choice and ot you have
to buy expensive ones to get good starting and colour!
Also CFLs do not seem to be a good or necessary choice for locations
where they are flipped on for a short time, such as stairs, cupboards
etc. they supposed to be used (like strip fluorescents) where they
will be left on continuously.
We have a bunch of those, with electronic ballasts, (from a school
renovation) in our workshop.
Interesting finding; what about switching power supplies also?
It is true that the old incandescent bulbs do provide heat, however,
like resistance heat, they are very inefficient.
I think what you meant to say is that using electricty only** is a
very expensive way to make heat. That doesn't meant that incandescent
light bulbs are an inefficient way to provide heat. I believe that
they are 100% efficient, in that all the electric power that is used
is converted to heat and light, and the light is converted to heat
when it lands on a surface (except for the light that that gets out
through a window.)
Light is absorbed by a black surface and converted to heat at that
time. Light is partially reflected from a white surface, so part of
the energy is converted and part is reflected. You can tell that not
all of the light is reflected because if it were, when the light
source is turned off in an all white room, there would still be light
inside the room, when in fact it goes dark almost instantaneusly.
**As opposed to using electricity to power a heat pump or an oil
furnace.
IIRC a good heat pump
will provide about four to six times as much heat as a resistance heater
or incandescent for the same power consumption.
That's because the heat pump brings heat from the outside to the
inside, and the electricity just powers the process. An electric
powered coal stoker, that brought coal from a coal pile to a coal
furnace would generate even more heat per KWHour, although I don't
know that people would call a coal stoker an even more efficient means
of heating. Although maybe they would.
EJ in NJ