Hello everyone,
Greetings for the day
We are doing daylighting simulation for the project which will be registered under LEED Version 4.
As per the requirements of LEED v4 EQ Cr7, the project should get 300lux to 3000lux for at least 75% of regularly occupied spaces.
Our project team is working for the same, but we are unable to control illuminance at 9am & 3pm due to low altitude of sun. More than 30% of spaces are getting more than 3000 lux level.
How can we reduce these more illumination areas to improve the percentage of comfortable daylighting?
Note:
• Shading devices are provided already. These shades are not working well at 9am & 3pm (low altitude of sun).
• We are using Ecotect plus Radiance
Please help...
Jill Dalglish, PE
Lighting EngineerMKK Consulting Engineers
LEEDuser Expert
440 thumbs up
June 12, 2014 - 9:29 am
You describe the requirements for Option 2. Simulation. What is the latitude of your project? What is the transmittance of the windows? Can you lower the transmittance value of the windows and still maintain the lower limit on the illuminance level?
Eddy Santosa
Director of SustainabilityDBR Engineering Consultants
376 thumbs up
June 12, 2014 - 3:58 pm
Please be careful with modeling with Ecotect+Radiance. You may not be able to fulfill the requirement for v4. You can model your surrounding building and contour.
SSN Energy Model
Mechanical Engineer5 thumbs up
June 13, 2014 - 1:20 am
Latitude - 6.2 South.
VLT 67%
Sunny Sky (9am & 3pm).
If i reduce the VLT, my overall daylighting will reduce.
I want to convert these more illumination areas into comfortable daylighting areas. Pl help
Jill Dalglish, PE
Lighting EngineerMKK Consulting Engineers
LEEDuser Expert
440 thumbs up
June 13, 2014 - 9:14 am
SS,
Without knowing anything else about your project, it will be difficult to make reliable recommendations as good daylighting can be a very complicated thing. For example, if you are stating that your project is 6.2 degrees south of the equator, it is in one of the best places for using horizontal sunshades to block direct light. Comparatively, your project has one of the highest sun angles at 9am and 3pm. I'm guessing I don't understand what you mean by 6.2 South.
Yes, lowering the VLT will reduce the overall daylighting and this was the idea. I don't know what your levels are now, but if you could afford to lower the overall daylighting to bring down the high values to within range, I don't think you'll be disappointed. Sixty-seven percent VLT is a high number.
This is a very difficult credit to achieve. I believe you can have good dayligting and not meet the credit requirements, but it would take a much longer evaluation of your project to determine the viability of either of these outcomes. It is probably out of the scope of this forum. I would be happy to help you further independently if you would like.