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    • CommentAuthorSimonH
    • CommentTimeNov 16th 2008
     
    I'm at work on a Sunday and was appalled to find all the lights left on from Friday. Woudln't be too bad if there weren't 96 4x18W fluourscent tubes or about 7 kW.

    I'd already been putting a business case together to get intellignet lighting done and had assumed a 5 days x 12 hour lighting pattern. So it should make it much easier to justify.

    However - anyone know of real world costs and savings of such systems. I have costs of kits from various wholesalers, but wondered what typical costs are for replacing a 8 way panel with an automated backend with internal light level, dusk sensors and seasonal timers. And anyone seen any real world savings. I think a straight replacement of the switches would be cheapest , but there's potential to swap 25mm T8 tubes for lower energy T5 tubes which can also be dimmed with suitable replacement ballasts. This is useful in our building as we get lots of daylight at certain times of day so along with luighting zones could throttle back the energy use.

    My fag packet calcs worked out £4,000 a year current, £1,500 potential. That was before I realisied they were potentially left on at night / weekend!. This includes a demand based change which is based on your peak use - usually taken sometime around 4:30 pm on a cold winter night. Even if we spend £5,000 in the first year it will pay back in 2 years.

    The short term fix is going to be sticking explanations of the lighting switches next to each switch and encouraging my colleages to use them - I think everyone thinks security turn them off - which they don't.

    The worst thing is this is one of 3 floors, which itself is one of 18 buildings we have in our vacinity ( I work for a large company). I dread to think what wastage we have, but have now found the person to talk too - we actually have a Green representative. The next hurdle is working out who pays for the lighting bill and has the most to gain - my company, the landlord, facilities management company, or the client (who subleases the building to us)!!?

    Simon.
    •  
      CommentAuthornigel
    • CommentTimeNov 16th 2008 edited
     
    You can convert T8 lighting to take T5 Bulbs - much cheaper.http://www.saveiteasy.co.uk/electronic-ballast-conversion-units.htm

    An light and motion system based on zones would seem the most sensible.

    A good control system will also reduce lighting loads in the summer and save on cooling requirement to remove excess heat from the offices.
    • CommentAuthorstephendv
    • CommentTimeNov 17th 2008 edited
     
    The light and motion sensors seem like a much better idea than a timer. Means that the lights can adapt to circumstances, e.g. everyone finishes early on friday or there's no one in on bank holidays etc. Our quite small office has them fitted and they're on small groups of lights, so if you're the only one in on a sunday then just the light above your desk would be on.
    • CommentAuthorSimonH
    • CommentTimeNov 17th 2008
     
    Thanks for the link Nigel. Its a nice quick way to do it without having to wire in a new ballast. Less automation potential (ie.e .no dimming) but will include several cost scenarios in the business case.

    I've also been reading more on this - a good ideas seems to be cut down the overhead lighting to minimum legal levels, (300 lux I think it was) and just have 500 lux over the walkways. Luckily this is possbile due to the way the banks are arranged. Then you can add "angle poise" lamps over the work areas, which people turn on individually. The advantage of doing this is that light level falls off in proportion to distance (twice as dim at 2m as it is at 1m) so bringing the light source closer to the desk means a lower wattage can be used. In my office, the desks are usually occupied about 60% but the bank occupancy would be 100%. So cutting the overhead and going individual would work better... as long as people turn them off when going to meetings! I can see see us needing countdown timers on them :-(

    The other think seems to be have an internal light sensor for each bank so lights can follow the sun. Although today we do need all the banks on.

    Stephen - The idea of timer is for the corridor lighting - where it would always be dark, but there are actually 2 light circuits - one to maintain a minimal background level - and another day time which doubles the light output. So the second circuit could be on a timer. The seasonal timer can be used for external lighting like pathways etc, but yes - i think these are best left to light sensors - then they would also work during an eclipse, or volcanic eruption ;-)

    Toilet lights need PIR sensors and probably an "occupied switch sensor " too, as I found out the 2 of the 4 loo lights had been left on too!

    I'm trying to find more about something my last employer was investigating - apparently there's an occupancy system which is based on you using a PC. I.e. if it detects you are at your workstation (and presumably typing and/or sending network traffic) then your bank will be lit up. haven't found it yet.

    Simon
  1.  
    I've often thought this could work in a domestic situation. Occupancy sensor could turn of lights a couple of minutes after the room is empty, with the sockets turned off after more than 30mins or so, you could also have a kill switch near the door so you can just knock out the room in one go as you leave, no standby devices + and very handy if you want to leave dramatically in the middle of an argument! Some sockets would be on an 'essentials' circuit that's unaffected. Perhaps if you wanted to get really swish a control interface a bit like the power settings on a windows PC and the sockets turn off one at a time and the lights dim off (where the LED or dimable CFL naturally).

    J
    • CommentAuthorchuckey
    • CommentTimeNov 19th 2008
     
    I would not go with any form of dimming , the colour of the light changes. Corridor and toilet lights should be on a PIR,so they switch on when required with a photo cell. This is a cheap mod. and actually makes life easier for those like me who used to be the only person (except for security) in an office block that has 200 + desks and many other areas, for manufacturing/drawing/wiring/software developement. etc. Walking down a 100yard corridor , even if its dead straight lit only by moonlight is very spooky!
    Depending on their work, the actual illumination of any given work area is a very person sort of thing, I think the cheapest option is to go with desk lights with a CFl bulb, or two or what ever the desk user needs, BUT arrange them to have a 1hr timer that dims them to off over say 2 minutes. So the user will have to switch them on every hour, this takes care of personal preference, hours of working, time of year. . .
    There could be some legal hassle about relative lighting levels, as the factory acts were written before timers, PIRs, light level sensors etc.
    P.S. While you onto this sort of thing - How many PCs are left on, with just their screens dimmed?
    Frank
    • CommentAuthorDaveK
    • CommentTimeNov 19th 2008
     
    Maybe you can persuade your company to implement ISO 14001 Enviromental Management?
  2.  
    <blockquote><cite>Posted By: James Norton</cite>I've often thought this could work in a domestic situation. Occupancy sensor could turn of lights a couple of minutes after the room is empty, with the sockets turned off after more than 30mins or so, you could also have a kill switch near the door so you can just knock out the room in one go as you leave, no standby devices + and very handy if you want to leave dramatically in the middle of an argument! Some sockets would be on an 'essentials' circuit that's unaffected. Perhaps if you wanted to get really swish a control interface a bit like the power settings on a windows PC and the sockets turn off one at a time and the lights dim off (where the LED or dimable CFL naturally).

    J</blockquote>

    The application works better for industrial situations, but as a lot of residential properties have cats and dogs, I think theyd be setting the things off at all hours.
  3.  
    Ok so the dimming out thing is a bit over the top but what about the kill switch?

    J
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