CHALLENGE: How to get an efficient yet professional and/or decorative looking T8 fixture without losing most of the light and energy?
Sarah Austin
guess it's evolving into something, based on some observations.
The thought process started with bird lighting, as I mentioned.
Look at the right hand photo on page 2 of this:
http://www.naturallighting.com/pdf_files/interior_fixtures.pdf
These are fixtures that we bought from this company for our bird
lighting. They can be purchased with an optional polished reflector,
which costs significantly more. ( $45 in this case, though I'm wondering
if add-on reflectors like this could be found for less? )
But it's great because so many light fixtures lose or waste an enormous
amount of light and energy because of not having a polished reflector
like this.
This fixture holds two 48" T8 tubes but look at the amount of reflected
angles of the tubes that it projects downwards:
http://lakewoodcolorado.net/Sarah/T8%20fixtures%20with%20reflectors.jpg
Then I go to a friend's office who's a local professional.
His office is professional looking and leased, so he has limited options
of changing things. But the lighting over his front desk is dismal, at
best.
It appears to have four T12 cool white tubes, stuck up in the ceiling
and most of the light output is blocked by a diffuser lens, so it casts
a bluish gray pall of light down into the room. Plus 50% of the light
isnt even being projected downward. All that for 160 watts of light, so
I'm guessing that 80% of the light and energy is kept up in there and
wasted.
But hey, it looks "professional" for an office setting, and is what most
offices use. He has little choice, it seems, being the office is rented
and it has to look professional.
So I'm getting intrigued by this.
We have these fixtures in the bird room and they're great for the birds.
People expect them in there, so fine.
But being they're much more efficient and project most of the light
downwards and outwards so it's useful light, it still makes no
difference in the rest of the house, or office, where people expect
"decorative" and/or "professional" lighting and they'd be appalled if we
used these same fixtures.
( Home Depot sells a less expensive shop light that's similar to this
called "Diamond Plate" by Lithonia
http://www.lithonia.com/product/resi.aspx?
pt=Decorative+Fluorescent&family=140
but again, it has an industrial look. You might get away with it in a
loft setting, but not for decorative or professsional office use.
It has a similar polished reflector, though it doesnt seem to project
quite as well. )
But think of the energy saved and the light that can come out of just
two of these T8 tubes. What a waste NOT to have fixtures like these that
CAN be tastefully used in settings where people expect professional
and/or decorative lighting styles.
So here's the challenge for lighting designers, as I see it, and I think
an enormous amount of good, AND energy savings, is to be gained by
meeting this challenge.
Come up with fixture designs that arent fancy or expensive ( I happen to
like fake woodgrain metal ), yet incorporate this polished reflector
efficiency and energy savings ( more light projected down from two T8
tubes, means less need for having 4 tube fixtures to compensate for it,
thus significant energy savings ), yet will work from up in the ceiling,
hanging from the ceiling, for example over a desk, by lamp chain, or
that can be surface mounted on a ceiling.
It needs to be open, with no diffuser, so that the polished reflector
can efficiently project the maximum amount of light down into the room
area. Yet it needs both decorative and professional looking choices of
enclosures that can be offered with it, so that people can accept this
enormous advantage in light output and energy savings in professional
and decorative settings.
I think that those who can meet this challenge AND market it to the
public, can reap enormous profits in a world conscious of energy costs
and the need to save and conserve.
Victor Roberts
<SAu...@pndfnospam.com> wrote:
>This goes back to the topic I started posting about here recently, but I
>guess it's evolving into something, based on some observations.
>
>The thought process started with bird lighting, as I mentioned.
>
>Look at the right hand photo on page 2 of this:
>http://www.naturallighting.com/pdf_files/interior_fixtures.pdf
>
>These are fixtures that we bought from this company for our bird
>lighting. They can be purchased with an optional polished reflector,
>which costs significantly more. ( $45 in this case, though I'm wondering
>if add-on reflectors like this could be found for less? )
>
>But it's great because so many light fixtures lose or waste an enormous
>amount of light and energy because of not having a polished reflector
>like this.
Polished, or spectral, reflectors do reflect more light than
white diffuse reflectors, but the difference is no where
near "enormous." (Your perception of the difference in
reflectivity is biased by the fact that spectral reflection
is highly directional, while diffuse reflection, is, by
definition, not.) In most cases, we care about the total
amount of light emitted by the fixture, not only the light
emitted in one direction.
Also, in some applications, spectral reflectors produce too
much glare and are not used for that reason.
>This fixture holds two 48" T8 tubes but look at the amount of reflected
>angles of the tubes that it projects downwards:
>http://lakewoodcolorado.net/Sarah/T8%20fixtures%20with%20reflectors.jpg
>
>Then I go to a friend's office who's a local professional.
>
>His office is professional looking and leased, so he has limited options
>of changing things. But the lighting over his front desk is dismal, at
>best.
>
>It appears to have four T12 cool white tubes, stuck up in the ceiling
>and most of the light output is blocked by a diffuser lens, so it casts
>a bluish gray pall of light down into the room. Plus 50% of the light
>isnt even being projected downward. All that for 160 watts of light, so
>I'm guessing that 80% of the light and energy is kept up in there and
>wasted.
While T12 lamps, especially those on magnetic ballasts, are
far less efficient than T8 lamps on electronic ballasts,
your estimates that 80% of the light is trapped are far too
high.
>But hey, it looks "professional" for an office setting, and is what most
>offices use. He has little choice, it seems, being the office is rented
>and it has to look professional.
[snip]
--
Vic Roberts
http://www.RobertsResearchInc.com
http://www.cflfacts.com
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Sarah Austin
> Polished, or spectral, reflectors do reflect more light than
> white diffuse reflectors, but the difference is no where
> near "enormous." (Your perception of the difference in
> reflectivity is biased by the fact that spectral reflection
> is highly directional, while diffuse reflection, is, by
> definition, not.) In most cases, we care about the total
> amount of light emitted by the fixture, not only the light
> emitted in one direction.
I'd bet that if you put a device below each fixture and measured the
total light out ( diffused or not ) that many of these closed fixtures
would be putting out 30% of the open reflector ones we have.
> Also, in some applications, spectral reflectors produce too
> much glare and are not used for that reason.
Hmm.
> While T12 lamps, especially those on magnetic ballasts, are
> far less efficient than T8 lamps on electronic ballasts,
> your estimates that 80% of the light is trapped are far too
> high.
I'd love to have the equipment to prove it.
TKM
"Sarah Austin" <SAu...@pndfnospam.com> wrote in message
news:Xns9CAE981F6A3BSn...@216.196.97.142...
What you're asking is, of course, what (good) lighting designers do
routinely. It's hard to go into a big box store or even lighting stores
which have professionally-trained staff and get luminaires which are more
than a match to your aesthetic desires. Appearance usually trumps anything
else especially in residential lighting where the luminaires are seldom
phtometered (because of the extra cost), so it is difficult to know how
efficient they are.
But, as I've indicated previously, luminaire efficacy (lumens/watt) and,
better yet, application efficacy where lumens delivered to the visual task
or lighted area per watt is a figure of merit is being applied more than
ever.
What you can do is ask for luminaire efficiency (lumens out of the
luminaire/lamp lumens) or luminaire efficacy (lumens out of the
luminaire/input watts) where you buy luminaires or via e-mail to the
luminaire manufacturer. Eventually, enterprising manufacturers will get the
message.
By the way, a polished reflector is not necessarily the most reflective.
White paint of high reflectance and properly applied can actually reflect
more light. A polished reflector can "aim" the light more accurately
though.
Also, any luminaire with T12 lamps these days is not optimized for efficacy.
Luminaires designed for T8 or T5 lamps will likely do better.
One final point -- fixture efficiency is important; but there is a classic
trade-off between fixture efficiency and glare. A bare lamp hanging in a
room has 100% fixture efficacy, but it's not good office, school, etc.
lighting today. Now, we put the "green eyeshades" on the luminaires,
instead of the people who work in the space because low glare lighting where
there are important and difficult visual tasks increases human productivity
which is usually the reason that electric lighting is installed.
Terry McGowan
Sarah Austin
Over my desk, I find that by putting the light directly overhead,
between the monitor and me, it keeps it out of my eyes, while doing a
great job of lighting. I've been running an open fixture that way for
years.
> Also, any luminaire with T12 lamps these days is not optimized for
> efficacy. Luminaires designed for T8 or T5 lamps will likely do
> better.
>
> One final point -- fixture efficiency is important; but there is a
> classic trade-off between fixture efficiency and glare. A bare lamp
> hanging in a room has 100% fixture efficacy, but it's not good
> office, school, etc. lighting today. Now, we put the "green
> eyeshades" on the luminaires, instead of the people who work in the
> space because low glare lighting where there are important and
> difficult visual tasks increases human productivity which is usually
> the reason that electric lighting is installed.
I'd have no problem with that, except for the transmission loss of the
diffusers.
hr(bob) hofmann@att.net
> "TKM" <nom...@no.net> wrote :
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You could put aluminum foil above the bulbs or even a cut-down el-
cheapo wall mirror that they sell for mounting on walls at Walmart or
K-mart for 1/3 or less of what you said you paid for a reflector.