Active vs Passive Daylighting systems

The only system I know is called 'dead reckoning'.

Its where you turn the lights on if its dark and turn them off if its light.

John.

I was expecting something rather professional, not janitorial. But thanks for at least being awake so early in the morning.

I don't know where you are but here its 2 o clock in the afternoon - but good morning anyway!

Oooops! just re-read your post, you're in Michigan USA....

Pesumably you are talking about controlling lighting in a big building...

I'm with Electroman on this...
GPS and computercontrolled systems seem like a case of overthink and 'complicating to the point of uselessness'.

The bottom line question is ..'when do you wwant the lighs on' ...
answer...'when it is dark'
This would be easilly achieved by a sensor in each room. Computer controlling an entire building is a recipe for disaster.

Keep it simple.....

A light sensor in each room is actually 'tracking the sun'...
The system you describe sounds like something sold on a late night shopping channel to gullible people with more money than sense.

Del

Hmmmmm Del, you've given me an idea for a revolutionary new product to sell on ebay...

Ohhhh I think its already been done, they sell security lights which switch on when it gets dark and switch off when it gets light???

Only a couple of quid each as well

Hmmmmmm, Guest I wonder why the street lights don't do that?

They work on if its dark turn on, if its light turn them off...

I guess a passing car's headlights must make for one hell of a confusion?!!

John _{releases ferret from its leash}

D'oh, read this after the next post!!

Ok..Smarty Cat.

So the sensor sees it's dark and turns on the lights...then
The sensor sees it's light so turns 'em off...
So the sensor sees it's dark and turns on the lights...then
The sensor sees it's light so turns 'em off...
So the sensor sees it's dark and turns on the lights...then
The sensor sees it's light so turns 'em off...
So the sensor sees it's dark and turns on the lights...then
The sensor sees it's light so turns 'em off...
Whadda you do eh? eh? Smarty Cat.

Smites furry head with mallet

That is exactly how the smart ones work.

A really dumb one works on a timer.

PS Beware of the sharp ends of cats.

Is this what seemingly intelligent engineers do on their days off, or is this one of the leading causes of our continued dependence on fossil fuels. How close are you to retirement? The sooner, the better.

I think you need to lift the sensor out of the lit area, if it was on a lamppost and had become detached and was in the lit area of the street light this is just what would happen.

Idiot!

I do believe that I have found the system and it seems that it has been installed in several major corporations. I would wonder if you are gainfully employed at this time? Perhaps I mis-understand the difference between a scientist and an engineer. Scientists search until they find the plausible answer, engineers justify their continued existence, along with their consultation hours, by convincing their employers and clients they know the answers already. Hmmmmm. I believe the reason for turning off the electrical lighting during the daylight hours by using daylight brought inside, would be to reduce the use of electricity. The result is saving money, reducing greenhouse emissions. That is about as simple as possible.

Maybe read my profile?
Maybe read my post?
As Bob Dylan once wrote..

'You don't need a weatherman to know which way the wind blows..'

Similarly you don't need a solar tracking computer system to know if the sun is shining.

Hmmmmm. I believe the reason for turning off the electrical lighting during the daylight hours by using daylight brought inside, would be to reduce the use of electricity. The result is saving money, reducing greenhouse emissions.

Yes indeed, an excellent aim, which I never contaradicted... I merely said your suggested implementation sounded over complicated.

Del

Hi Yooper1946

All the controlled light systems I know of is passive, using on/off light sensors.

Adding an infrared sensor may turn the lights down when the office is empty in daytime or off at night.

An active system may also turn lights down at the lowest satisfying level for the occupant and thereby save some energy.

Maybe controlling the lights according to brain activity will save some energy as well.

Yooper1946,

There are products on the market using older 5mm (approx 1/4inch) fibre optics to bring daylight into office spaces.

The two that I know a little bit about both use fresnel lenses to collect the light from outout doors and bring it up to 20meters indoors via fibre.

One is passive and just becomes part of the fabric of the building,
the other tracks the sun by timers or a photo optic controller and collects more light.

Regards,
Sapper.

Thank you, it is a help, but after looking at the site, the light in the photos seems limited in its illumination field. It is a start though, thanks again.

Those illustrations are the basic concept for the system.

Depending on the diffusers on the emmitter end they will behave just like any other light fitting.

Regards,
Sapper.

The Japanese have a solar mirror reflector that follows the sun allowing the light to strike a bundle of fiber optic cables. These cables are then routed throughout the building to down light into special areas. The light spectrum is of course true sun light, so they filter it with diffusers over work stations. Decorative plants within the buildings grow very well from this natural light.

Passive day-lightening would entail building bigger windows and positioning building is such way to allow for maximum sunlight, numerous light diffusers and skylight are also used to reduce glare and minimize solar heat entering the building, in summer this is negative aspect of day-lightening, in winter this would obviously be positive aspect. Active day-lightening takes numerous forms; fiber optic transportation of light into rooms is one, sun trackers and heliostats would be other forms. please note that heliostats reflect sunlight onto the building (or other target), however the reflected shape of sun ranges from being highly ellipsoid (almost linear) to fairly circular, dependant on time of the day and position of the sun. There are numerous other reflecting forms on the market... follow links

http://www.lightkinetics.com/

http://zomeworks.com/products/sunbenderae-reflector-shade

http://www.iwilltry.org/w/index.php?title=How_to_build_a_heliostat_for_solar_heating_and_lighting

http://egis.org/index2.html

Passive "daylighting" is no system at all.

Here's a link to one vendor:

http://www.soluminaire.com/

This is one approach to solar illumination. A solar illumination retrofit builds solar lighting into an existing building. Active solar illumination uses moving reflectors to enhance the collection of daylight.

Heating, cooling, and lighting a building without the expenditure of additional energy is called passive solar heating, cooling, lighting, and so on. Passive solar is almost always better, because the cost of installation is the last cost, except for maintenance. Unfortunately, this is not often possible in a retrofit.

Heating, Cooling, and Lighting by Norbert Lechner is an accessible book that addresses these topics in some detail. It's worth a look if you are interested in optimizing the relationship between buildings and their environment.

I guess what I mean by active daylighting involves a system that is not just a skylight in a roof. The desired light level would be maintained throughout the building, room by room by an active system. The only light coming through a passive skylight would simply shine into the room whenever the sun is in a position to enter the hole in the roof.

Ah Yooper...I have re-read the original thread...

It is somewhat ambiguous...
I now gather you are want to actually use the Sun's light for illumination rather than just controlling the lights (which was the original impression).

The only real way to do this effectively is in the original architectural design of the building.

Adding light pipes (which are commonly available and very effective... ) is rather problematical.
Any idea of adding solar tracking and GPS is still barking mad on grounds of complexity.
Del

(PS. You shoot down post#7 who appeared to be chastising me by showing that a simple room sensor would cause oscillation/hunting!? I'm not sure how both #7 and #4 can be wrong?)

I'll go a step further. I don't see any possible way to use GPS in this application. Is the building moving?

Tad

I looked at Yooper's link in #24.
The mirror looks like it's on a simple little motor (motor/gearbox ass'y) powered/directed by a little solar cell, a bit like those solar lights you can get for the garden. (I hope they are more reliable than those )
Nice enough idea but I wouldn't fancy the repairs... it probably gets quite hot in there....How many would you need an a building.

I think the whole point of passive lighting is the 'passive'.

Maybe the GPS is just marketing bull?

Del

It uses GPS technology as an automatic locator, therefore making it unnecessary to program the location. It is not equipped with a GPS unit. The mirror is moved by the motor, which is powered by a rechargable solar battery. The battery storage is 30 days even if not exposed to sunlight. The dome is equipped with a dual thermal barrier, bring heat gain/loss to an absolute minimum. Go on the website, watch the product demos, and the testimomials. I found the company's founder and was able to talk to him. I will be flying out to Las Vegas to the LightFair to meet them and several of their satisfied customers. They have appointed a distributor for the Eastern half of the USA, Green Power Management of New Hampshire. Staples, a major office supply company, here in the USA is installing the Ciralight system in 20 of their stores in Connecticut next month. They had an independent lab test the system and are ready to roll out with it. This is not some newfangled gadget, it has undergone testing and weathered things quite nicely. Each Ciralight requires a 48" X 48" opening, illuminating 400SqFt. By placing the systems on the roof at a proper spacing, the individual rooms should be very nicely illuminated. It is very simple, not complex at all. Now, you guys get ready for the next really cool thing. A very affordable LED replacement for T8 florescent tubes. Go away you annoying flickering buzzing toxic long white thingys. This technology is coming out of Korea, special coating on the surface of the LEDs to significantly kick up the lumen output.

"I overheard a discussion between a representative and the purchasing agent . "

Maybe before you start slagging off everyone here...you should ask yourself how 'Scientific' these two guys were?

Guest #7

If you go this post (You're an engineer if...) you'll find one characteristic I mentioned that seems to describe what you just said (...you make things incredibly simple or overly complicated).

Okay, let's say you go ahead and want to track the sun to utilize sunlight for lighting a building (using light pipes, reflectors, etc). Would I use GPS? Certainly not! Light sensors would do nicely. The sensors would determine where the sun is by following the bright spot in the sky.

In case of clouds, the system would switch to a simple motorized thingamajig (the name escapes me, it's something telescopes use to track stars, equatorial-something). Once the sun comes out of the clouds, the light sensors just pick it up again.

What you overheard sounds a little fishy. If it was a rep and an design engineer, I wouldn't wonder but a rep and a purchasing agent? Sounds like a deal in the making.

I found a website www.ciralight.com This is what I am looking for, since our buildings are all flat roofs, with ceiling heights no higher than 36 ft. Seems it has been on the market for a while and according to people who actually bought and installed it, saves a great deal of energy, improves human performance, and in retail stores has actually been proven to increase sales when properly researched by independent agents. This looks like it will do the job for our retrofit. My brother is a top engineer for Masco Corp near Detroit, he says it won't work. That is why I will go ahead to pursue it. He always shoots down anything I learn about before he does. When he goes on the defensive, that usually means it will not work, it can have tremendous results. It is a big/little brother syndrome thing. I will post further info as I pursue this. Thank all of you for you input, some of the more juvinile responses were better than yesterday's funny papers, so not all was lost.

Ahhhh I am so glad to hear that you do have a sense of humour afterall....

John

I meant to say that when my little brother says something that I learned about before he did will not work, it will indee work very well.

I'm not convinced a well designed static reflector wouldn't be as almost as good, cheaper and more reliable?

Whadda ya think guys eh? eh? eh?

Del

I have learned that this product is being used by companier in England, quite successfully I might add eh eh??

Is that like a magnifying glass held above the little ants on a sunny day.

Using natural light is very good but artificial light must be installed as well. Even at 100% use of natural light there would be days when it must be supplemented. Yesterday for example it was heavily overcast in sunny SA.

Some of the shops also require to be open outside of daylight hours.

Also bear in mind that less light is available in winter.

Some intelligent control is needed.

I have located a company that has developed a wireless light control system to bring the artificial lighting up to the required foot candles or lumens. This total system of the Cira light combinte with dimmable LED florescent replacements, seems will provide us with what we need for our circumstances. We will let everyone know when we decide to test this in one of our 24/7 warehouses. The lighting cost is currently over 300,000USD/year. I don't yet know the costs involved, but we will do it if we can recover costs in 3 to 4 years. There may even be some sort of government tax incentive to retrofit the skylight system.

Look at http://www.solar-track.com/ I met them at an International Green Summit Conference last month, currently have a number of installations with Retail and Fortune 100 companies many whom attended the conference.

I would provide contact details but can not locate their card. If I do find shortly I will send you a PM