LED lamps and polystyrene slabs

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roboc
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LED lamps and polystyrene slabs




by roboc » 13/10/11, 11:06

Hello everybody

I'm in the process of having my basement finished and the ceiling is made of polystyrene humps. A false ceiling in BA13 will be placed approximately 2cm from the slabs (ceiling height required).

I would like to install led spots on the ceiling. I installed spotlights in the light fixture of one of my children (Xanlite xxx and the results are as good as with the old 50W. I have the impression that these spots hardly heat up, including rearward).

Suddenly, do you think it is possible to dig the slabs (kind of spaces of e 20-30 cm in width and 10 groin in height) by spot to be able to embed them?

I would not do it with classic 50W spots, but there the question arises!

Thank you for your help.
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by Christophe » 13/10/11, 11:37

Yes you have to dig them: there are still watts to dissipate even if 10 times less than with a halogen. You can do the test by enclosing a led bulb in a small insulated box, after a few (tens of?) Minutes, it will be as hot as a halogen (which is it after a few seconds)

So if you do not dissipate these watts, in the end, it will obviously heat up with the risks that we imagine!

To know the dimensions of the safety space to create, I think you should ask the seller, if not the manufacturer ...

Ah my opinion, will not get wet and advise you the same as with halogens (the norm is the norm) ...
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dedeleco
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by dedeleco » 13/10/11, 14:07

The downside is that LEDs have a lifespan that plummets the body with temperature and softened unless nothing at the usual temperature of fluorescent lamps (not to mention the usual spots), which do not seem huge but kill the LEDs quickly !!!
So insulating the LED lamp even in a little insulation, is a delight for sellers of LEDs who will then sell 10 to 100 times more, at very high prices !!!
If the LED heats up a little internally (40 to 80 ° C) its lifespan (50000 to 80000 hours when very cold) tumbles enormously by 10 to 100 times less !!

So it must be well cooled to T of the room (no more than 10 ° C more !!!) with full of drafts, which often remain weak because the LED with only 10 ° C more does not trigger a detectable thermal convection air flow !!!

So put the LEDs clearly visible, ventilated, far from corners and even lampshades which cut the air circulation !!

Otherwise they must be cooled with solid metal which is a good conductor of heat or cold (copper or aluminum).

Otherwise you will change them 5 to 100 times more often !!!

See the scientific LED life curves already put on econology, to reflect and also those of the heat exchanges by convection (put for VMC double flux !!) !!

Otherwise the old 50W spots with their transformer buried in the ceiling insulation without any air circulation, do not last long, not to mention the real fire risk (personal experience with my electrician 10 years ago who forced me to take over with my hands the whole installation of these spots so that the air circulates around !!)
Last edited by dedeleco the 13 / 10 / 11, 14: 15, 2 edited once.
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by Christophe » 13/10/11, 14:10

+10

Right, I thought about it but I did not dare to talk about it so as not to scare Roboc since it is his first participation :)
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roboc
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by roboc » 13/10/11, 14:16

Thank you for these responses.

The plaster ceiling will be 2 cm and it is expected that air can circulate. In fact, I double my walls, also leaving a space of 2cm of air between the insulation and the concrete block wall. High and low ventilations in the partitions to circulate the air behind + VMC for the renewal of the air which will come from English courses with opening on the outside to bring in the fresh air (in all senses of the term), like with CMV which is in the rest of my house.

The 2cm of the ceiling will be 'in engagement' with the two cm of air from the partitions. so normally, it should ventilate.

The hole in the insulation will still be important so I hope it does not heat up too much for my dear ones : Mrgreen: led (not even afraid of deleco and Christophe :? )
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dedeleco
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by dedeleco » 13/10/11, 15:31

The best test measure the T of the LEDs on site during operation (max 10 ° C more) !!
The ventilation between wall and insulation reduces the insulation, so calculate it well.
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roboc
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by roboc » 13/10/11, 16:00

Except that I will not be able to measure ... the ceiling is not yet put and when it will be put ... the holes will have to be made!

For the ventilation between wall and insulation I did not calculate anything :? it was my architect who advised me to do this. The basement is completely buried and he thinks that helps prevent possible risks of humidity on the wall.

On the other hand the question which arises is: should one leave the two small current openings to ventilate with the outside air between the wall and the partition and put a grid at the bottom of the walls to "pull" all this with the CMV?
Or should we close the two small current openings, and only make, from the inside, high and low openings on the wall?

But here we leave the starting point!


For now the only thing I could see on this wall is condensation ... but that was before I broke everything in the basement : Mrgreen:
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Re: LED lamps and polystyrene slabs




by hic » 13/10/11, 17:22

roboc wrote:Hello everybody

I'm in the process of having my basement finished and the ceiling is made of polystyrene humps. A false ceiling in BA13 will be placed approximately 2cm from the slabs (ceiling height required).

I would like to install led spots on the ceiling. I installed spotlights in the light fixture of one of my children (Xanlite xxx and the results are as good as with the old 50W. I have the impression that these spots hardly heat up, including rearward).

Suddenly, do you think it is possible to dig the slabs (kind of spaces of e 20-30 cm in width and 10 groin in height) by spot to be able to embed them?
I would not do it with classic 50W spots, but there the question arises!

Thank you for your help.

Hi Roboc

Alternatives
Embed on condition of cooling with a passive external radiator
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roboc
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Registration: 13/10/11, 09:37




by roboc » 13/10/11, 18:42

It is for what type of spots passive radiators
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dedeleco
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by dedeleco » 13/10/11, 21:52

Once mounted, drilled, with LED radiator in direct contact with the LED (different from incandescent spots) measure the T in situ, (small thermocouple or other fine thermometer).

Sinon the next problem is full of traps even for an architect (at least the one who worked for me and who lost to justice for poor workmanship !!):
For the ventilation between wall and insulation I did not calculate anything. It was my architect who advised me to do like this. The basement is completely buried and he thinks that will prevent possible risks of humidity on the wall.

On the other hand the question which arises is: should one leave the two small current openings to ventilate with the outside air between the wall and the partition and put a grid at the bottom of the walls to "pull" all this with the CMV?
Or should we close the two small current openings, and only make, from the inside, high and low openings on the wall?
For now the only thing I could see on this wall is condensation ... but that was before I broke everything in the basement


Indeed the physics of the condensation of water vapors (and its evaporation) is essential and therefore we must think carefully about the temperatures and degrees of hygrometry at different periods of time.
Summer and winter are very different, otherwise the VMC can have the opposite effect of condensing all the external water vapor on the wall (summer case with T outside higher than T inside !!) with a quantity of water proportional to the flow of humid air coming from outside !!
Phenomenon identical to the condensation in a wide open fridge with the fan of VMC sending the hot air inside !!

If not reflected the VMC can be a machine to make humidity !!

Ask this architect for a quantitative analysis with T wall, T outside air, function of the seasons,% humidity of the outside air also variable, VMC flow, size of the openings, and quantity of water condensed or not !!!

It is also necessary to check if the wall is porous to the humidity of the soil and if a correct drainage exists around the house to remove the humidity from the soil !!

If your architect does not give an analysis that you clearly understand thoroughly, you can be sure of errors !!!

In my case, 10 years ago I trusted too much and for lack of supervision by my architect, I had humidity (without VMC which would not solve anything, poorly drained soil), and won a lawsuit against this architect and his mason !!!
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