Question-and-Answer Resource for the Building Energy Modeling Community
Get s tarted with the Help page
Ask Your Question

LED lights fields radiant, visible, convected

asked 2015-04-01 08:13:51 -0600

Alex Vlachokostas gravatar image

updated 2015-07-26 19:03:22 -0600

Under the object lights; E+ considers for fluorescent (FL) lights the following default settings: fraction radiant is 0.72, fraction visible is 0.18, and fraction convected is 0.10. These values are well referenced from the IES lighting handbook.

I would please like to ask if you can suggest well referenced values for: 1) LED lights (e.g., 4ft tube type). (a) radiant, (b) visible, and (c) convected fractions and 2) how much less energy (W) do LEDs consume (e.g., % less than fluorescent).

Thank you.

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2015-04-06 16:06:50 -0600

When the latest edition (Tenth Ed.) of the IES Lighting Handbook came out, the LED replacement lamps for 4' fluorescents were still kind of in the "Wild West" phase, with lots of new product and performance claims but little test data. The DOE's "CALiPER" testing program has addressed this quite a bit; you may find some info in their detailed reports to at least offer some guidance on part one of your question.

As for part two, the manufacturer's data will tell you how much less (possibly) energy the LED lamp uses, but remember that the input watts are only part of the story when evaluating direct replacement of one light source for another.

edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer


Question Tools



Asked: 2015-04-01 08:13:51 -0600

Seen: 2,244 times

Last updated: Apr 06 '15