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      CommentAuthorDamonHD
    • CommentTimeDec 16th 2011
     
    http://www.energysavingtrust.org.uk/Publications2/Energy-efficiency/Lit-Up-an-LED-lighting-field-trial

    http://www.bbc.co.uk/news/science-environment-16199552

    Discuss.

    (We're all LED or CFL at home, basically, though it would be nicer to get slightly higher lumens output in standard bayonet/screw fittings.)

    Rgds

    Damon
    • CommentAuthortony
    • CommentTimeDec 16th 2011
     
    a) do we need lighting to be so much brighter?

    b) I cannot see where they have allowed for the increased heating energy needed to replace the loss of "wasted" heat energy from the old lighting --- THIS IS VERY SIGNIFICANT.

    c) I agree that LEDs will take over.
    •  
      CommentAuthorJSHarris
    • CommentTimeDec 16th 2011
     
    <blockquote><cite>Posted By: tony</cite>

    a) do we need lighting to be so much brighter?

    b) I cannot see where they have allowed for the increased heating energy needed to replace the loss of "wasted" heat energy from the old lighting --- THIS IS VERY SIGNIFICANT.

    c) I agree that LEDs will take over.</blockquote>

    a) Interesting point. Yes, in some areas, no in others. In my view few houses have a "lighting design" a few lights are stuck in with little regard to the needs of the occupants in each area of the house.

    b) The pat answer to this is to just improve the thermal/airtightness standard of buildings to compensate, plus rejoice in the fact that heat isn't being wasted during the times of the year when lighting is needed but heating isn't.

    c) LEDs might well be the next wave of light-producing devices to gain a significant share of the market, but I somehow doubt that LEDs will stay as the "best" lighting solution for long, as they are still relatively inefficient (in absolute terms) especially when driven from high voltage supplies.
    •  
      CommentAuthorDamonHD
    • CommentTimeDec 16th 2011
     
    Tony: a lot of those lights are *exterior*. Are you really going to claim that their heat output is useful at *any* time of year?

    Rgds

    Damon
    • CommentAuthorneelpeel
    • CommentTimeDec 16th 2011 edited
     
    Posted By: tony
    a) do we need lighting to be so much brighter?

    b) I cannot see where they have allowed for the increased heating energy needed to replace the loss of "wasted" heat energy from the old lighting --- THIS IS VERY SIGNIFICANT.


    a) Possibly not, but one of the main points was that the colour temperature was improved as well. Although I guess this could have been achieved by better bulb selection in the first place.

    b) As pointed out above, this is only for part of the year. Also, in social housing much of these bulbs may be in stairwells, corridors and the like where no heating would be required. Finally, heat could probably be more efficiently created using the gas boilers, etc that are likely installed in the accommodation.
    I think it only makes sense to use bulbs to create heat in rare circumstances like your own Tony where a house is extremely well insulated and has no other means of heating.

    d) Longer life (I.e. less maintenance) could be a big benefit in social housing.

    e) Can see bulbs getting nicked once people realise they are worth £30 a pop.
    • CommentAuthortony
    • CommentTimeDec 16th 2011
     
    a) do we need lighting in stair wells and corridors on 24/7? or even all the time when it is dark? -- Exterior lights should all be LED's but NOT on during daylight see their photos!!!!

    b)It is most unscientific and misleading to claim that all the energy saved is being saved when some has to be replaced by additional heating -- money and efficiency issues aside

    d) agreed not just social housing but anywhere people are paid to change luminaries,
    • CommentAuthorCWatters
    • CommentTimeDec 16th 2011 edited
     
    That energy saving trust project is interesting but I noticed they say it involved 4,250 LED fittings costing £900,000. That works out at £211 per fitting. I suppose they were more expensive in 2008 but even so.

    The average payback calculated was 20 years but the range was from 1.4 years to 92 years.

    Quote: Value of energy saving is based on an average unit price of 13.95p (2008 prices)

    That seems high for 2008?
    • CommentAuthortony
    • CommentTimeDec 16th 2011 edited
     
    The higher the cost figure for electricity used the better the savings look
    • CommentAuthorwookey
    • CommentTimeDec 16th 2011 edited
     
    Cwatters: Some of them include emergency lighting features too, which will push up the cost. Commercial fittings like this, especially specced for public areas and outdoors will be surprisingly expensive, even when not LED.
    • CommentAuthordjh
    • CommentTimeDec 22nd 2011
     
    I finally got around to reading the report and found it very disappointing. It seemed to have been written by a marketroid or a spin doctor rather than an engineer or scientist.

    It was very difficult to find hard raw facts in the report, it all seemed to be 'normalised' in different ways in each table and there was very little information about what was installed originally, making it difficult to judge any comparison about savings etc.

    Much was made of different colour temperatures, attributing this as a benefit of LED technology. But both LEDs and fluorescents are available in pretty much any colour temperature you ask for. So as far as I can tell, its simply a different opinion by whoever chose the old and new lighting. As someone who prefers 'daylight' lamps himself, I'm well aware that most people choose 'warm white' - that's why it is most commonly available. It's got nothing to do with LEDs.

    The published photography was hopelessly biassed. (The report writer's bias rather than the photographer's). If I understood the methodology correctly, they deliberately used under-exposed pictures of the original lighting where it was dimmer, which of course makes it look terrible. They should have also published at least the correctly exposed original lighting and the corresponding over-exposed new lighting if they wished to be objective. I think they also deliberately used the wrong colour balance, which again is an unfair trick.

    With regard to the hours of lighting, it looked to me like a lot of this lighting was public safety and security lighting, so it's not too surprising that it was left on 24 hours a day. People having confidence in their own safety is more important than the last bit of energy saving. It is true that modern automatic daylight control systems can help achieve both goals in the right circumstances and these are increasingly being fitted.
    •  
      CommentAuthorDamonHD
    • CommentTimeDec 22nd 2011
     
    There was a long long note by the photographer at the beginning saying how they avoided adjusting any colour balance and made sure that they took exactly paired shots by exposure, etc, before and after.

    Rgds

    Damon
    • CommentAuthordjh
    • CommentTimeDec 22nd 2011
     
    Posted By: DamonHDThere was a long long note by the photographer at the beginning saying how they avoided adjusting any colour balance and made sure that they took exactly paired shots by exposure, etc, before and after.

    Exactly. That's how I know it was the writer's fault not the photographer's. Read it again and think about what they wrote in the context of what I said.
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