LED street lighting the newest challenge to old utility business models

Post by waterlesscloud » Thu, Nov 28, 2013, 7:46 AM UTC

abduhl wrote: post #17

tghw wrote: post #16

Earlier quoted context omitted.

They could be built as a part of the light, since we're changing all of that out anyway. Really not that hard. Also, contractors shouldn't be studying compliance for new things. And you would pay them as you're installing the new lights. So not out of the "goodness of their heart" either. In fact, I have no idea what you're trying to get at here.

Most items installed on a transportation project must meet the standard specifications for the state which generally incorporates federal requirements as needed. Anything installed must be "per spec" and manufacturers or contractors installed items that are not per spec can be grounds for a refusal of payment or refusal of acceptance. Specifications compliance is solely the responsibility of the contractor (who gener…

Post by ars » Thu, Nov 28, 2013, 7:58 AM UTC

BIair wrote: post #15

I wonder what percentage of street lights actually have activity below them? What about a motion sensing light that has dual-brightness levels? A lower level when no pedestrian or car activity is detected, and a brighter level when it is. Not only would this save energy, and look very cool when a car drives down a deserted street as lights brighten in advance of it, but it could enhance security as late night prowler…

Post by mkesper » Thu, Nov 28, 2013, 8:15 AM UTC

abduhl wrote: post #13

Tyr42 wrote: post #10

Earlier quoted context omitted.

Check out http://ledsmagazine.com/features/2/5/8 It says that: The energy consumed by a 100-watt GLS incandescent bulb produces around 12% heat, 83% IR and only 5% visible light. In contrast, a typical LED might produce 15% visible light and 85% heat. You can't always put a LED light in a enclosed fixture, as it might even overheat. It needs some air flow to cool it's heat sinks.

The question is a matter of power then. A 100W bulb at 5% light is 5W of light (assuming power vs energy can be compared this way... I don't do electrical engineering) which would correspond to a 35W LED producing less than one half of the heat when you consider that snow piling up in front of a light and the light enclosure will convert the IR to heat.

Post by adrianN » Thu, Nov 28, 2013, 8:45 AM UTC

ars wrote: post #25

This doesn't make any sense. A high pressure sodium vapor lamp has an efficiency of around 150 lm/W. An LED has an efficiency of under 100 lm/W. Where is the energy savings? If anything an LED uses more energy, not less.

Post by dagw » Thu, Nov 28, 2013, 8:55 AM UTC

arsemouflon wrote: post #29

This is how you add redundant non-information to a sentence: "semiconductor-based, solid-state LED lighting". Someone who doesn't know what a LED is surely won't understand that "clarification". Marketing mindset!