Light design compatability/setup

[gazdkw82]

Hi,

As previously mentioned iv been working on lighting design for a family members industrial unit.

I have made designs and ran light output examples with chosen fittings etc on Relux and they are more than happy with what iv come up with.

I have got 3 quotes and they are happy with the final cheapest quote. Almost £1000 cheaper than anyone else has got.

I have then done a yearly, 5 year and 7 year breakdown of costs (current set up and proposed set up)

All looks good, however I am a little unsure on the actual set up within the office area. Within the office area will be x18 LED panels with daylight harvesting. I was then planning on having a PIR so that when people are out the office dealing with deliveries etc the lights can be turned off.

I am concerned the PIR and daylight harvesting wont be a good combination. Is one of the ideas behind daylight harvesting that a PIR is not needed?

Thanks

 

[The Ghost]

Must be a large office for 18 panels! Daylight harvesting, imo, is a trumped up term for a light/lux sensor. A PIR usually will have a lux sensor in it. Frankly although the ideal is that if there is 75% light through natural means there should only be 25% light by electrical means being balanced all the way through, however there are quite a few situations where this cannot be achieved. I have not found a lux sensor that is reliable in say a corridor that has windows all along and flooded by light. Maybe I have just not found the right product yet.

 

[gazdkw82]

These are jcc panels. They are not cheap and are supposedly one if the best for this feature.

Yeh it's a fairly large office but only 2 people inside and some large windows down one side.

It seemed the best idea to go for daylight harvesting (lux sensor) in order to reduce power consumption and maintain a minimum lux level. The fittings will only measure the lux levels directly under it but that's not s problem.

Unfortunately all 18 fitting are on 1 switch and will be too intrusive to change to split the office up into banks

 

[The Ghost]

JCC are good and have a good light quality. KSR do some interesting equivalents. How many sensors are you using? I think if there are only two people in it then 18 panels defeat the whole idea of energy saving.

 

[gazdkw82]

Was thinking of using 2. One either side of the room

 

[The Ghost]

Do they require a neutral? If so it means you will have to get into the wiring for the lighting and put the switching through the sensors. Which means you would be so close to the switching and fiddling about you could (easily?) rearrange the switching to split the lighting. Each sensor maybe switching a different area. I am curious though as to the exact size of the office must be about 150 m²?

 

[gazdkw82]

Nope it's 75m².

TBH I've not put much planning into the the office area other than just changing the existing 4x18w fittings with led panels. What I'll do is run another scene on relux for the office and reduce the amount of fittings because it's obvious to me now that 18 will be far too many.

Reduce the amount of fittings = reduce installation costs = reduce energy consumption.

This is my first attempt at lighting design so forgive my obvious blunder here :-/

 

[The Ghost]

The thing about lux sensors is that they are very myopic and only "see" a very short distance. I fit a lot of sensors and have been dissapointed with the efficacy of them re lux sensing. Consequently I reason that a separate lux sensor master situated close to natural light would be more effective. Just a theory at the moment but will be incorporating it into current work load fitting sensors.

 

[Adam W]

Are you looking at the JCC Skytile Sense? I've had a quick look at those and they appear to cost about £360 each, compared to around £25 for a 'normal' 600x600 LED panel, which should have a very similar power consumption. That could bring your price down by another £6000 or so.
I think I'd be going down the route of 'normal' LED panels with a PIR sensor in the middle of each group of 4 (layout permitting), which will also switch the lights off if there's sufficient daylight.
If they're 600x600 fittings in a suspended ceiling it won't be too difficult to alter the wiring; worst case scenario you could short out the switched live and just use the switch position as a test switch. 18 fittings on one switch sounds like a lot - are you sure it's not controlling several circuits via a contactor?

18 panels does sound like a lot for the size of the room - my experience of LED panels is you need fewer than you would with a fluorescent 'equivalent'.

 

[gazdkw82]

Yeh they are the skytile sense panels. I've got them for £68 a panel.

They are stated as being able to monitor lux levels up to 3m from ceiling to floor.

 

[The Ghost]

Personally I am not sure it is worth paying that extra for JCC. LED is developing so rapidly and the prices falling with more and more facility such as sensing, colour changing etc. that within the lifetime of the lamp it is going to look like a bad investment. I agree with @Adam W the £25 route is better. Also if you have four fluors. then you may well get away with two LED panels.

 

[gazdkw82]

Iv ran a scene on Relux for the office. Its now got 11 fittings in rather than 18. That's averaging out 500 lux throughout the office. I'm quite happy with this layout. Feedback would be more than welcome.