Is it possible in Openstudio to set the intensity of the artificial lights, depending of the daylight comfort and of the temperature?

asked 2016-10-03 12:32:40 -0600

poppo92
875 ●3 ●14

updated 2017-05-04 08:48:45 -0600

__AmirRoth__

4436 ●5 ●17 http://bleedinggreenna...

In Open Studio I set the number and the intensity of the artificial lights in every thermal zone, and the schedules as well. I would like to know if it is possible to set a certain value of daylight comfort for a large office. The lights are internal gains, and I want to avoid overheating problems in summer caused by artificial lights, without loosing the daylight comfort. Something like in Summer is too hot and the daylight is good --> the artificial lights decrease their intensity, but they rest switched on (or switched off if the natural daylight reaches a certain value). So is it possible to vary automatically the intensity of artificial lights during the summer days when daylight is good and temperature is too high? Thank you

answered 2016-10-05 01:01:14 -0600

David Goldwasser

20395 ●94 ●14 http://www.openstudio.net/

updated 2016-10-05 07:29:23 -0600

OpenStudio and EnergyPlus can controls lights based on daylight comfort by using the Daylighting Control object. They don't however offer a way to factor in zone or outdoor temperature or to change the Daylighting Control object characteristics seasonally. If you want to do either of those you would have to use EMS (Energy Management System) objects in a measure. You could also manually adjust the lighting schedule to mimic this by lowering the peak levels lower in summer vs. winter.

If your goal is just to avoid any excessive electric lighting, could you just set the Daylighting Control characteristics at the lowest level that provides enough light all year round, or do you want to be more aggressive in summer than in winter with target lighting level?

The thing to be careful about is that OpenStudio and EnergyPlus do not run an electric lighting simulation to calculate lighting levels. If you undersize your HVAC system you will see unmet hours. There isn't any obvious indication of an under lit building. You need to look at the efficacy of your lighting technology and make sure that the installed and scheduled lighting power (installed watts * fractional schedule value at timestep) is enough to light your zone.