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High efficiency table tennis lighting

Discussion in 'Lighting' started by markp, Sep 1, 2003.

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  1. markp

    markp Guest

    Hi All,

    My TT club currently has five 500W halogen lamps per table. They are
    prone to overheating and are very inefficient, but the lighting quality is
    excellent.

    We are now looking for more efficient lighting systems with longer lifespan.
    They should have the same colour spectrum as the halogens and not have any
    strobing effects.

    Does anyone have any recommendations for high efficiency alternatives to
    halogen lighting? From what I've read so far it looks like we will need a
    colour temperature of around 3000K and a very high CRI. High frequency warm
    flourescents look interesting, but is it possible to use a combination of
    HPS and HID to give the desired spectrum, if so how do you reduce the
    strobing effects?

    Any info or links appreciated!

    Mark.
     
  2. First, I should say I am a light source and ballast designer. You may
    get different and perhaps better answers from the lighting designers
    that frequent this group.

    To eliminate strobing you should use high frequency (electronic)
    ballasts. These are common for fluorescent lamps, but now just
    starting to be available at reasonable cost for HID lamps. Also, HPS
    has terrible color rendition, and while metal halide is better, it is
    not as good as fluorescent.

    I recommend that you use high CRI tri-phosphor T8 lamps on commercial
    grade electronic ballasts. Some electronic ballasts have inadequate
    line frequency filtering and will produce flicker. There is no way to
    identify these high ripple electronic ballasts from the ballast data
    sheet. You might be able to get power line ripple data from the
    ballast manufacturer, or you may have to test products yourself.
     
  3. Why is very high CRI relevant to TT?
    Do you put priceless artworks round the walls,
    or lay out fabric samples on the table?
     
  4. markp

    markp Guest

    No, but people are used to playing under halogen and incandescent lights
    which do have very high CRI. The shirts players wear for example are
    multicoloured, the balls can be yellow or white, bat surfaces are red and
    black. It must look as much like incandescent lighting as possible otherwise
    people are going to barf at it. The venue we have is purpose built for TT
    and is of international standard, in fact we've had international matches
    played there. We're not talking about a leisure centre ping-pong setup,
    otherwise we wouldn't have 2500W of halogen lighting over each table!

    Mark.
     
  5. I would highly recommend to use a high efficiency Compact Fluorescent Lamp.
    (With a built in Ballast). Check out www.turolight.com.
     
  6. I'm not sure the term "warm white" is used with tri-phopshor lamps, as
    it was one of the "official" colors for halophosphate lamps. It seems
    you need a 3000 K lamp, or perhaps even a 2700 K if it is available.
     
  7. markp

    markp Guest

    As far as I can see this way of describing colour temperature still seems to
    be used, e.g :
    http://www.edw-uk.com/e-wholesaler/ewcats/cat8212.htm

    Mark.
     
  8. The designations used on the Web site you give seem to be made up by
    the distributor. Neither the Philips North American catalog or the
    Philips UK Web site use the term "warm white". In addition, Philips
    uses TL-D in Europe instead of T8. The use of "warm white" could be OK
    to describe a 3000 K lamps except for the fact that there is no
    indication which of three Philips warm white lamps they are *really*
    selling.

    Philips has 32-watt T8 lamps with 3000 K rare earth phosphor with
    three different CRI's: 78, 86, and 95, using the designation TL730,
    TL830 and TL930. From the site you give I can't figure out which of
    these 3000 K Philips lamps is being sold as "warm white".
     
  9. Also note that this distributor gives a rated *voltage* for each of
    the T8 lamps. Fluorescent lamps are rated for an operating *current*,
    not voltage. While they do have a typical operating voltage when
    operated at rated current and rated temperature, the operating voltage
    of a 600mm long T8 lamp is less than a 1200mm long T8 lamp, which in
    turn is less than a 1500mm long T8 lamp which in turn is less than a
    1800mm long T8 lamp. Yet, this distributor lists the voltage of each
    of these four lamps as 240 volts!
     
  10. JM

    JM Guest

    quoting:

    500w hologen lamps are aprox. 10,500 lumens each.

    5 x 10,500 = 52,500 lumens


    For standard T8 fluorescent lamps, you would need aprox. 19 32w lamps to do
    the job. The resulting wall of lamps would probably run too hot and
    inefficient.

    T5 HO 80w lamps are approx. 6,500 lumens each. You would need only 8 lamps
    to do the job. Downside is ballasts will operate only one lamp, so 8
    ballasts will be needed. Input power 91w per ballast will yield approx
    52,000 lumens for all 8 ballasts, with 72 LPW system efficiency.

    ballast: Sylvania QTP1x80T5HO120PSNE 120V 20/CS 1/SKU
    lamp: Sylvania FP80/830/HO


    T8 HO 86w is approx. 7,600 lumens initial each. You would need 7 lamps to do
    the job at 1 BF. Each ballast can operate either 1 or 2 lamps each, so you
    would need only 4 ballasts. Input power for the two-lamp ballasts is 185w,
    and the one-lamp ballast is 99w, total 654w input power. This will yield
    53,200 lumens @ 81 lpw initial system efficiency.

    ballast: Advance RCN-2S86
    lamp: Philips F96T8/HO/TL830 PLUS ALTO
     
  11. markp

    markp Guest

    Thank you very much for providing this information!

    The lights at the moment are standard halogen floodlight types mounted to
    point downwards. They actually had to drill holes in the top to stop
    overheating, but they also had to mount quite high above the table to spread
    the light out evenly. The general feeling is they can be brought down to 2/3
    of this height with suitable reflectors which I guess would just about halve
    the amount of light needed (assuming square law). This has to be
    experimented with, but you have given me an excellent starting point to do
    this.

    Thanks again!

    Mark.
     
  12. I don't understand your message here. See below.
    Four-foot, 32 watt T8 lamps are more efficient than either T5/HO or
    T8/HO lamps. For the same amount of light they would produce less
    heat, not more, in spite of the fact that you would need to use more
    lamps. T5/HO or T8/HO might be the best lamps for this application,
    but not because they would be more efficient or cooler.
     
  13. markp

    markp Guest

    Would that not require more ballasts? Wouldn't the inefficiencies that this
    introduces negate the extra efficiency of using 32 Watt T8 lamps over T8 HO
    lamps?

    Another quickie if I may, presumably these electronic ballasts have high
    power factor inputs as standard. Is that correct? This is of concern for
    lighting many tables.

    Thanks!

    Mark.
     
  14. markp

    markp Guest

    OK, For each electronic ballast I assume there's an active PF correction
    circuit producing DC which is then used to drive some kind of inverter (?).
    Having many active PF correctors and inverters to me is less efficient than
    having one of each, but having thought about it more there's going to be
    higher current in a larger one and lower current in the smaller ones and
    some power loss is proportional to the square of the current, so I'm not
    sure now whether that logic stands up!

    For example are you saying that four small electronic ballasts driving one
    lamp each would have the same efficiency as a single large ballast driving
    four lamps?
    OK, I'll check. Why high PF input stages need nowadays to have high inrush
    currents is a little confusing, I thought they would use active power factor
    correction circuit with controlled smooth inrush, but I'll look out for it
    too!

    Thanks!

    Mark.
     
  15. AC/DCdude17

    AC/DCdude17 Guest

    X-No-Archive: Yes

    A 500W halogen lamp can put out 10,000 lumens from a lamp no larger than a
    pencil.

    To get the same amount of light out of F32T8 fluorescent lamps, assuming each
    puts out 2600 lumens on a ballast factor 0.88 ballast(considered normal output),
    you'll need four lamps and each one of these lamps is 4' long by 1" diameter and
    light can not be focused the same way a halogen light can.

    Since you have five halogen lights per table, you're looking at installing
    TWENTY 4' lamps.

    Once you figure out how you're going to arrange those twenty lamps, it's not
    hard at all.


    What kind of halogen lamp do you have? If you have a standard RSC T3 (similar
    diameter and slightly shorter than a pencil), you can try a GE HIR lamps. They
    will put out the same amount of light as 500W halogen while using 350W. While
    it's not the best result, it's an improvement.
     
  16. As far as I remember, no one in this discussion has claimed that
    fluorescent lamps are as small as an incandescent lamp that produces
    the same amount of light. And, until we know more about THIS
    APPLICATION, it is not clear that five concentrated sources would be
    better than 20 larger sources.
     
  17. From his earlier post, you'll find he's currently using floodlamps
    pointing downward. You can't assume that he's using a 500W T-3 bulb in
    a fixture. He also says they're mounted quite high off the table to get
    a uniform illuminance around the table. He also says that he will be
    bringing the lights 2/3rds closer to the tables, so matching fluxes
    won't work in this case.
     
  18. If the same size wire and power semiconductors were used, it might,
    but higher power ballasts used larger wire and ferrite cores in their
    transformers and inductors, and larger power semiconductors. The goal
    is to keep the ballast efficiency in a "reasonable" region while not
    making it too expensive.
    Well, we started discussing "normal" power linear lamps vs. fewer HO
    lamps. But the situation is basically the same for two lamp vs. four
    lamp ballasts. I will have to check the manufacturers data to give you
    a real answer, but my experience is that most electronic ballasts
    operate with an efficiency of about 90% or slightly better. I will
    check some real data and get back to you.
     
  19. I did say that, but, here is one comparison that indicates I am wrong.

    Consider two rather normal and similar electronic ballasts: the
    Advance REL-2P-32-SC and the Advance REL-4P-32-SC. The first runs two
    32 watt T8 lamps with a ballast factor of 0.88 while consuming 58
    watts. The second runs four of the same lamps at the same 0.88 ballast
    factor while consuming 112 watts. This means that one REL-4P-32-SC and
    four 32-watt T8 lamps will operate with 3.6% higher efficacy than two
    REL-2P-32-SC ballasts and the same four 32-watt T8 lamps. Note that
    the input wattage numbers are rounded to the nearest watt, so the
    actual difference in efficacy could be different than the number I
    calculated.

    The question for HO lamps is different in. In this case the HO lamp is
    less efficient than the normal power lamp, so any improvement in
    ballast efficiency would have to more than offset the loss in lamp
    efficacy. Let me see if I can find some data.
     
  20. OK, here is an example of HO vs. normal power lamps. I decided to use
    T5 because the T8 situation is more complicated. Most regular power T8
    lamps run on instant start electronic ballasts while all HO lamps are
    rapid start or one of its variants, such as programmed rapid start. On
    the other hand, all T5 lamps run in programmed start or programmed
    rapid start mode. I also decided to compare two-lamp systems, because
    as shown in my previous note, there is a small difference between
    two-lamp and four-lamp ballasts. It is also important to compare lamps
    with the same length, as, all else being equal, longer lamps will have
    higher efficacy.

    The first system uses an Advance [email protected] programmed start ballast
    operating two Philips 46-inch F28T5/830 lamps. The lamps are rated for
    2900 lumens at 28 watts, the ballast has a ballast factor of 1.03 with
    two F28T5 lamps and draws 64 watts. This gives a system efficacy of
    93.34 lm/W.

    The second system uses an Advance [email protected] programmed start
    ballast operating two Philips 46-inch F54T5/830/HO lamps. The lamps
    are rated for 5000 lumens at 54 watts, the ballast has a ballast
    factor of 1.0 with two F54T5 lamps and draws 120 watts. This gives a
    system efficacy of 83.33 lm/W.

    The normal power T5 system has higher efficacy.

    BTW - premium T8 lamps on premium instant start electronic ballasts
    can have system efficacies as high as 98 lm/W. So they beat both T5
    systems.
     
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