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RE: LED lighting

asked 2014-11-18 08:20:29 -0500

RMAK gravatar image

updated 2014-11-18 09:46:42 -0500

Hello, I was wondering if there is a way to model LED lighting in Openstudio ? If so how would I do it ?

Kind Regards, RMAK

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answered 2014-11-18 09:53:25 -0500

There are multiple ways to model lighting in OpenStudio. The type of lighting (LED, T5, CFL, MH, etc) doesn't really matter to OpenStudio and EnergyPlus.

You can specify individual lamp types, and then place the lamps individually within each room, using multipliers where appropriate. Use this if you have shop drawings which show which lamp types and how many in each room.

You could also specify a lighting power density, and apply it to a space. You would use this if you don't know specific lamps, and only know a target LPD.

You could also specify a lighting power per person in the space.

You can also control how the lamps are implemented: how much of the lighting energy is heat vs how much is light, as well as how much heat from lighting goes into the return air plenum.

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answered 2014-11-18 09:51:43 -0500


Sure, you'd do it the same as you would model any other electric lighting in OpenStudio. You could start with an existing lighting load schedule and modify it to reflect the actual luminaire load of your LED light fixture (source plus driver). OpenStudio and EnergyPlus do not model the actual photometric distribution of luminaires, so you don't need photometry files; you just need to know the individual load(s). Make sense?

And before you ask, the OpenStudio Radiance support does not currently support spatial distribution simulations, either. =(

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answered 2014-11-18 10:36:56 -0500

RMAK gravatar image

updated 2014-11-18 10:50:45 -0500

Thank you everyone. I love this forum :D


Sorry but I came across another problem. An LED light uses less Watt than the usual fluorescent lights so for example if I put the power consumption for a LED panel to be 45W then how would open studio know that, that is sufficient lighting ? I mean Open studio wont know that LED lights has a higher light efficacy. Would this be a problem in the model ?

Kind Regards, RMAK

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Yep, this is why I ranted thusly, here: Without a proper lighting design analysis, you can't know whether your lighting design is satisfying the other very important aspects of a lighting design. You can do a simple zonal cavity analysis to see if your new layout is meeting design criteria such as task illuminance, but EnergyPlus doesn't really care about such things. The onus is on you to ensure that the proposed design works as a lighting design before doing the energy analysis.

rpg777 gravatar imagerpg777 ( 2014-11-18 11:09:52 -0500 )edit

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Asked: 2014-11-18 08:20:29 -0500

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Last updated: Nov 18 '14