Saving on lighting cost for underground car park

[tomtomato]

Hi,

I live in a block of flat that has a large underground car park. In the car park, all the fluorescent lights are always on, so the electricity bill is quite large (about £2,500 just for those).

We have about 60 tubes (58w each).

I was thinking about getting some motion sensors to be installed, but advice given was that switching on/off the tubes frequently would reduce their lifespan (I would expect around 50 cycles per day) and also those take a while to switch on (so safety concern).

When going abroad, I see many private car parks with fluorescent tubes and motion sensors, so surely, it can't be that bad of a solution.

In order to have a fairly quick return on investment, I don't really want to spend more than £2000 on the project, so replacing everything by LED lights is probably out of scope. My understanding is that replacing fluorescent tubes by LED lights require some modification to each fitting (ballast and starter), so on top of buying the lights, the labour cost is likely to be high.

Any ideas?
Thanks,
Tom

 

[bhm1712]

every place ive ever worked has PIR's on the office lighting because trying to get office staff to turn off lights is almost impossible they just cannot be trained to do it. They dont take long at all to turn on - no different than if you flick the switch. It depends how old the control gear in the light fittings is. I wouldnt have ever imagined its a safety concern, and the cost to replace lamps would not cost as much as the electricity to run them 24/7. In fact, they still last a long long time when on a pir.

 

[tomtomato]

Thanks.

Those were installed about 10 years ago. As there is no switch currently, I don't know how long they take to switch on. As cars would enter the car park at speed, there is a safety concern that the lights could take a while to come up.

Reading on forums, it seems that there are many different opinions on connecting PIRs to fluorescent lights...

 

[bhm1712]

well as said, ive worked in loads of factories and all of them had PIR's on fluorescent tubes in various offices throughout. I have seen it in airports, car parks, toilet blocks, offices.....loads and loads of places. Its never been a problem where i have worked either so it must be ok.....50 cycles a day is not a massive figure if you divide it by 24 hours. How big is this car park? how many cars can it hold?

As for the cars entering the car park and turning the lights on, why not have a inductive sensor just before the entrance which will activate the lights? and have a PIR for foot traffic....

 

[bhm1712]

i just edited my above post so re read it!

There are other types of lights which could be used, and maybe even the lighting design of the car park could be changed. It would cost money but i doubt at £2500 a year that you currently pay, that it would take long to break even.

 

[tomtomato]

The car park is only for residents and has 30 spaces. So if we consider each car leaving and coming back once per day, it would be 60 cycles.

The car park has an electric gate, so maybe opening the gate (i.e. coming in) could also trigger the lights. As the gate takes a few seconds to open, this would give time for the lights to come up.

 

[bhm1712]

That would be a good idea with the gates. I would imagine it would probably be pretty easy to get a signal from the gate controller, or if not you could use a sensor attached to the gate...

Well if there are 50 fittings for a car park with 30 spaces, at 58 watt each maybe it would be an idea to split the lighting of the car park up a bit. Maybe it could have 2 lighting circuits. One which is on all the time providing ambient lighting to the main foot routes through the car park and access doors etc, and these would be low power single lamp fittings. And then have a second PIR and gate sensor activated circuit which provides lighting to the car parking spaces, driveways through etc. These can be the 58 watt fittings. Theres so many options

 

[dhutch]

That would be a good idea with the gates. I would imagine it would probably be pretty easy to get a signal from the gate controller, or if not you could use a sensor attached to the gate...

Exactly, keep the system isolated, just put a PIR by the gate, assuming thats not going to get a load of false triggers.

But I agree, that sounds like a hell of a lot of fixtures/tubes for only 30 spaces, its either fairly complex layout, or a lot of lights.

I presume there is not a lot or no naterial light, so you can/could have cars driving into darkness without there lights on.


Daniel

 

[OwainDIYer]

I would also suggest splitting the lights into always-on and PIR.

It might be worth painting the ceiling and possibly even the floor with lighter colour paint to reflect more light, then reducing the number and power of fittings.

The car park judged to have the best lighting was perceived to have an illuminance of 200-300 lux but the measured value was only 100 lux. This example provided a high degree of uniformity (more than 0.8) for both horizontal illuminance at floor level and vertical illuminance at 1.5m. The ceiling, floor and walls all had very light finishes so the overall effect was a bright appearance with no dark corners and where faces could be recognised
at distances up to 60m.

http://www.cibse.org/pdfs/factf2.pdf

 

[dhutch]

There is a lot to be said for spraying it all white!

 

[tomtomato]

Sure, apart from the cost and my budget of £2000 for the work!

I think spraying all walls and ceiling in white would cost more than my total budget.

 

[ricicle]

You need to ascertain what control gear is in the lights as a lot of PIRs don't like switching iron ballasts. HF gear will start pretty quick. I know an underground office car park that has fluorescents on a PIR and they don't have to change tubes that often as far as I know.
There are two PIRs - one as you drive in to the car park and one by the pedestrian door.

If they are iron ballasts and you can set up a system with contactors then it might be worth fitting electronic starters as they prolong the life of the tube and start them better in colder environments.

 

[bhm1712]

That would be a good idea with the gates. I would imagine it would probably be pretty easy to get a signal from the gate controller, or if not you could use a sensor attached to the gate...

Exactly, keep the system isolated, just put a PIR by the gate, assuming thats not going to get a load of false triggers.

But I agree, that sounds like a hell of a lot of fixtures/tubes for only 30 spaces, its either fairly complex layout, or a lot of lights.

I presume there is not a lot or no naterial light, so you can/could have cars driving into darkness without there lights on.


Daniel

I was thinking more of a spring roller switch which activated with the gate movement, or an inductive sensor which recognised the gate being in the closed position and activated the output when the gate starts to open.

My other idea was to have an inductive sensor in the ground like what you find at traffic lights etc. The car driving over it will activate the lights..

 

[RF Lighting]

I don't see an issue with using PIR(s). I've seen this done lots of times without any problems.

 

[SimonH2]

I think spraying all walls and ceiling in white would cost more than my total budget.

Actually, I suspect you might find that it gives the quickest and highest rate of return. If the walls/ceiling aren't a light colour now (eg raw concrete or blocks) then painting them white would vastly increase the brightness (actual and perceived) and you might find you could disable every other light fitting (remove the tube and starter) while still keeping it bright enough.

Doing that (removing some tubes) would also be something you can try without actually doing any modifications - and try different combinations at no cost other than your time.

AFAIK, with a magnetic choke fitting, it's OK to just remove the tube - we've taken quite a few out of the fittings in the office as it was too bright (typically taking 2 of the 4 tubes out of a 4foot fitting).

I have to agree with the others, it's hard to see why so many lights. I'm more accustomed to seeing one tube per group of spaces (perhaps 6 or rather than 2 tubes/space. So at first sight, it looks like you have 12-16 times ore fittings than it normal in public car parks !