Does Thermal Analythis consider light ray direction or diffused light ?

Dear all

Hi. I'm now trying thermal analysis to evaluate the performance of the daylighting louver.

I saw the description in this site that we are possible to "test the relative effect of different daylighting and controls strategies on the energy consumption of a typical daylit space". 

 

It was also explained that "Climate-based simulations including all desired shading and lighting schedules should be run before a thermal analysis. The generated schedules will be offered as input options into the thermal simulation."

So, I would like to ask how does the lighting schedule influence the thermal analysis. 

Will it be calculated by real light ray tracing situation, or the only light percentage will be considered and calculated ?

In our study, the light ray's direction (and diffused light) also influence the energy consumption.

Could you tell me the method of calculation used in DIVA ?

Regards,

Yuki

Views: 161

Reply to This

Replies to This Discussion

Hello Yuki,

Please forgive the late reply.

So, I would like to ask how does the lighting schedule influence the thermal analysis. 

Will it be calculated by real light ray tracing situation, or the only light percentage will be considered and calculated ?

When you run a full climate-based simulation in DIVA, two things are generated:

  1. A shading schedule -- when shades are up / down.
  2. An electric lighting schedule using a linear dimming system.

For this to work, both need to be defined in DIVA. Then these schedules are used as hourly inputs in EnergyPlus for a related thermal simulation . The first schedule controls the blinds, but only in a full up / full down state as EnergyPlus will not let you schedule more than open / closed in a reasonable way. The electric lighting system is scheduled in number 2. In this way, the results of the raytrace simulation are controlling the electric lighting loads and the shading state in EnergyPlus. Thermal gains are still calculated within EnergyPlus but based on the blind status determined in the raytracing analysis.

I hope that is clear!

Could you tell me the method of calculation used in DIVA ?

DIVA is using Daysim internally. If you want to read more about this, please see the below.

J.A. Jakubiec, C.F. Reinhart, DIVA 2.0: integrating daylight and thermal simulations using Rhinoceros 3D, DAYSIM and EnergyPlus. Proceedings of Building Simulation 2011, Sydney.
Full Paper
Presentation

Best,

Alstan

Deae Alstan

Thank you for your reply in detail.

Now I understand almost I wanted to know.

I wanted to evaluate the performance of the "fixed" daylighting louver, but it seems to be impossible to get how it influence lighting energy.

Thank you for the link about energyplus too.

Regards,

Yuki

Hi Yuki,

You can do that -- but you need to run a daylight simulation (1) with no operable shading but (2) an electric lighting simulation. Then in your energy model, you need to add your lover as a shading device(s) to the model on the ep_shading layer. When DIVA asks, load the lighting control schedule into the EnergyPlus model.

Best,

Alstan

Dear Alstan,

Thank you for early reply.I'll try that way.

Thank you !

Regards,

Yuki

Reply to Discussion

RSS

© 2019   Created by jeff niemasz.   Powered by

Badges  |  Report an Issue  |  Terms of Service