halogen efficiency

[Alex Coleman]

I am using four or five CFLs (a mixture of 11W, 15W and 20W) as room
lighting plus an 18W tubular rather than halogen. It may seem odd but
it is an ad-hoc arrangement to replace my too-warm 300W halogen
floodlight which I used to use!

http://www.aps.com/images/pdf/Lighting.pdf says that typical efficencies
are roughly:

CFLs = 20 to 55 lumens/watt
Tubular fluorescent = 60 to 100 lumens/watt

Is the 15 to 25 lumens/watt figure it gives for tungsten-halogen for low
voltage or mains voltage bulbs (which is 230v here in the UK)?

Does such a lumens/watt efficiency figure for low-voltage halogen
include typical power losses in the step-down transformer?

 

[Victor Roberts]

I am using four or five CFLs (a mixture of 11W, 15W and 20W) as room
lighting plus an 18W tubular rather than halogen. It may seem odd but
it is an ad-hoc arrangement to replace my too-warm 300W halogen
floodlight which I used to use!

http://www.aps.com/images/pdf/Lighting.pdf says that typical efficencies
are roughly:

CFLs = 20 to 55 lumens/watt
Tubular fluorescent = 60 to 100 lumens/watt

The low end of your ranges seem too low, unless you are
including some very small lamps.

Is the 15 to 25 lumens/watt figure it gives for tungsten-halogen for low
voltage or mains voltage bulbs (which is 230v here in the UK)?

These must be for low voltage halogen, as 230-volt lamps
with ratings of 100 watts and less usually are less than 15
lm/W as far as I know. (Someone from the Europe will have a
more definitive answer.)

Does such a lumens/watt efficiency figure for low-voltage halogen
include typical power losses in the step-down transformer?

Usually not. Unfortunately, lamp efficacy for all types of
lamps typically does not include the
ballast/driver/transformer losses.

--
Vic Roberts
http://www.RobertsResearchInc.com
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[Andrew Gabriel]

These must be for low voltage halogen, as 230-volt lamps
with ratings of 100 watts and less usually are less than 15
lm/W as far as I know. (Someone from the Europe will have a
more definitive answer.)

On one of GE's IR reflecting ones, 225W = 5000 lumens, which
is 22 lumens/watt. I don't have a standard halogen, but if I
assume this is same light output as a standard 300W halogen
(as the packet claims), then that would be 16.7 lumens/watt.

Usually not. Unfortunately, lamp efficacy for all types of
lamps typically does not include the
ballast/driver/transformer losses.

unless it's integral in the bulb.

 

[Jeff Waymouth]

The low end of your ranges seem too low, unless you are
including some very small lamps.




These must be for low voltage halogen, as 230-volt lamps
with ratings of 100 watts and less usually are less than 15
lm/W as far as I know. (Someone from the Europe will have a
more definitive answer.)




Usually not. Unfortunately, lamp efficacy for all types of
lamps typically does not include the
ballast/driver/transformer losses.

Vic, you comment that "the low end of (the fluorescent) range might be
too low". Unfortunately, you are incorrect. Consider the "specialty"
phosphors, for example F40DSGN50. This is a full wattage F40 with 2200
initial lumens for an LPW of 55.

Jeff Waymouth

 

[Don Klipstein]

Generally the higher end is for low voltage. The highest efficacy of
any low voltage tungsten halogen we could find on the market about
eighteen months ago was Osram IRC capsules, with the 12V 50W unit
delivering 26.4 lumens per watt.

With what life expectancy and wattage constraints is 26.4 lm/w the
ultimate overall luminous efficacy of low voltage halogen?
I suspect you are implicitly excluding photographic and projection and
similarly specialized lamps - I know of 32 lm/w there among low voltage
halogens - although with life expectancy impractically short for
illuminating my living room!

Well, yes 26.4 does look good compared to 120V ones 500 watts or less
and with life expectancy at least 2,000 hours and excluding the HIR
ones getting at most about 21 or 22 lm/w (as far as I know). Lower
voltage ones do better with some "economies of scale" that favor thicker
filament wire.

- Don Klipstein ([email protected])

 

[Paul M. Eldridge]

Hi Don,

I've had excellent luck with Osram Sylvania's 37-watt MR16 IRC which
is rated for 4,000 hours service. High efficiency, long life,
consistent product quality and a very competitve price (I pay the
equivalent of $6.50 US per bulb, in single quantities).

Philips has a 45-watt MR16 IR lamp that produces up to 1180 lumens
(26.2 lumens/watt); it has a rated life of 5,000 hours.

Source:
http://www.nam.lighting.philips.com...df?PHPSESSID=8283e7ee9bdb0cbbd54ade3fa9b28ec0

Cheers,
Paul