ASE CALCULATION

Thank you for your great program. I was wondering how to calculate the ASE with honeybee. I can get the grid based percentage of time over 1000 lux over the year but this is not exactly what ASE is, do you have any suggestions how it can be calculated using the honeybee components?

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Permalink Reply by Cheney on April 29, 2016 at 12:57pm

Hi Chris,

Thanks for the great example in the first place.

I am using your example file for a quick ASE test. But I notice:

by using this method, to get ASE1000lx,250h below 10% is almost impossible (even use your 4000lux as the benchmark)? Unless very abnormal sun shades are introduced.
the example is not sensitive to orientation? I just rotate the model by 180 degree and manage to observe ASE at North. The results are quite similar to those from South.

I have a feeling the example may 'overestimate' sunlighthours. But I am only a beginner of GH/LB/HB and probably I misunderstood it somewhere. Could you please let me know your comments? Many thanks!

Cheney

Permalink Reply by Chris Mackey on April 29, 2016 at 2:10pm

Cheney,

I don't have a hard time getting ASE1000lx,250h below 10% of the floor area and I get pretty expected results for a North-Facing room:

I attached the file with a North facgin room so that you can see how it works.

-Chris

Attachments:

Estimate of Glare Potential Over a Year_North.gh, 437 KB

Permalink Reply by Cheney on April 29, 2016 at 7:38pm

Wow, thank you Chris for your lightening reply. So I must do something wrong at my side. I notice you actually rotate the model in Rhino. What I did was to assign 180 number to "_north" at GH. Do the two methods generate different results? Anyway, I will double check my model next monday and report back to you if I still have questions. Thanks a lot and have a nice weekend! Cheney

Permalink Reply by Mostapha Sadeghipour Roudsari on April 29, 2016 at 10:06pm

What I did was to assign 180 number to "_north" at GH.

Grasshopper doesn't have project north like Revit. All the input should be assigned locally for the component. North component is just for generating a north arrow.

Permalink Reply by Cheney on April 29, 2016 at 10:29pm

Thanks Mostapha,

Two more newbie questions:

1.So for a parametric study, if I'd like to rotate my model for orientation testing, I can only rotate it in rhino?

2. When I apply 180 to "sun path", I see the diagram changes direction. It will not affect any calcultion result?

Regards, Cheney

Permalink Reply by Theodoros Galanos on April 30, 2016 at 12:36am

Hi Cheney,

I believe HB has a rotation study in one of the components but you can replicate that function quite easily in GH.

If your model is quite simple, and only used for daylighting, you can simply plug in its Brep to a rotate component and connect the output to the Run component. Then you can add a slider or values of the degrees you want it to rotate and use the fly component to run all values off of that. If you have true in your daylighting workflow that should generate parametric runs for you. Ofc, if I believe you can do the same thing on the North input of the Run components in HB.

Just remember to link each run to a different file name in the Run daylighting component so you don't overwrite your results each time (a concatanate component to do smth like NameOfSimulation_#Run would be enough).

There are other, a bit more intricate ways, which actually provide much more functionality and ease of working (once you are more comfortable with GH) if you create the model itself parametrically in GH. Then you just use a similar method to all the parameters that can be influenced.

Hope this helps.

Kind regards,
Theodore.

Permalink Reply by Cheney on April 30, 2016 at 12:35pm

Thanks Theodore, your reply gives me the confidence to proceed my parametric study.

Permalink Reply by Mostapha Sadeghipour Roudsari on April 30, 2016 at 5:30pm

Theodore already answered the questions but just for the future reference the short answers are:

1. No. You can rotate it inside Grasshopper either before creating Honeybee objects using Grasshopper native components or after that using RotateHBObjects component.

2. That will change the analysis results. My comment was about the north component and not the north input.

Permalink Reply by Theodoros Galanos on April 30, 2016 at 12:38am

This is a very interesting discussion, especially with the upcoming LEED v4.

I will soon try some calculations of the sort, I actually did use Chris's definition with very good results so far. However, I did not compare results to v4 criteria yet. In my specific region, I would think achieving ASE would be very easy due to very low direct illuminance, which makes it interesting for other people around the world to share any results they get on this.

I had a question on Alstan's presentation. Is it a LEED requirement or a sensible thing to calculate sDA by compiling the 3 scenarios detailed there. Is this how the calculation is performed in HB as well? By combining shades open/close and ab=0? I must be getting that slide (8) wrong I guess.

Kind regards,

Theodore.

Permalink Reply by Cheney on April 30, 2016 at 1:00pm

My two cents here...

sDA calculation and 2% rule are dictated by IES LM-83-12 and LEED v4 adopts sDA metric. Unlike DA or other annual metrics, blind operation should be embedded in sDA calculation. The aim is to prevent overestimating the amount of usable light or underestimating lighting energy consumption (Daylighting performance will be penalized when users will lower blind to prevent potential glare issue at certain period of time).

More details could be found at sDA and blinds operation

I have the same question whether HB can support sDA calculation.

Permalink Reply by Mostapha Sadeghipour Roudsari on April 30, 2016 at 5:27pm

Hi Cheney,

Currently Honeybee is using Daysim which unless you have only a single window in your room, or all the blinds go up and down together can't model blind operations as suggested by IES LEM-83-12. Sarith is implementing Radiance's 3-5 phase methods to Honeybee which will make the process possible.

Your best bet at this point is OpenStudio and using RadianceDaylight measure. Honeybee let's you to export the model as osm and then you can use OpenStudio for the rest.

We also have an experimental workflow under development that let's you run OpenStudio measures form inside Honeybee but it won't work for daylighting measure for some OpenStudio limitations that you can read here and here.

Permalink Reply by Cheney on May 1, 2016 at 11:18am

Hi Mostapha,

Thanks for your clarification!

Actually I am using one room+ single window in HB for my parametric study which will help architects make design decision at initial design stage. Am I right to say, based on your reply, that it is still possible to follow IES LEM-83-12 to estimate sDA in HB? It would be great if you are able to show me any example or workaround.

For LEED v4 calculation, currently I am using Diva4Rhino. But I am very interested in the HB/OpenStudio workflow and expect to compare sDA/ASE results generated by different workflows. According to my current understanding, it is very difficult to achieve LEED v4 daylight points under option 1.

Thanks again for your prompt reply.

Regards, Cheney