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Can you point out to what opening fraction you are referring to?

I would also recommend adding energy monitor for specific window(s). Like this: Output:Variable,WindowNameHere,Surface W

That is correct. No limit on BSDF resolution. Just make sure that basis definition matches matrix size.

EMS should replace it with CFS_Window and it looks like that is not happening. Will look into this as soon as I catch so

EMS should replace it with CFS_Window and it looks like that is not happening. Will look into this as soon as I catch so

I see now that visible optical data are not created. This seems to be a bug in WINDOW. Thanks for catching it. I will send you spectral data file that you can use to create glass layer in OPTICS which then you can import in WINDOW. When creating layer in WINDOW please put that layer to have very big conductivity and front and back emissivities equal to one. In this way you will be able to have thermal analysis of the system (please note that airflow will not be simulated correctly in this case) because "virtual" layer will block it.

Can you do that without using OPTICS. Do not copy any DAT file. Just got to glass library and create glass with perfect transmittances. Use that glass and not one copied from OPTICS. It is however interesting that you got the error by just copying data.

Did you try to create BSDF of single layer with perfect transmittance by itself? You cannot do that by applying single perfect layer (physics in optical routines break). Can you put triple layer right away and see how that performs?

You can use WINDOW7.4 for that (no need for OPTICS). As you already mentioned, you would have to put one glass layer that you can create in WINDOW. Just put 1.0 for solar and visible transmittances (it is important to put for both of them). Then create IGU with two shades and perfectly transmitted glass in between. Latest step would be to create Report->Energy Plus BSDF IDF (the only way to get BSDF matrices printed out). Note that if you turn debugging on, WINDOW will create Debug folder with layer by layer BSDF, which would be good way to check if data that WINDOW is using are correct.

Updated: You do have to go into OPTICS, make a 100% transmittance glazing. Import that into WINDOW and use that as the layer for the above procedure.

Alos to update on current status (limit here is 600 characters so I did separate comment). LBNL is finishing new shared WINDOW engine module that is replacing current somewhat conflicting set of 3 different modules with the one that includes all of functionalities of WINDOW. This new shared engine will also provide NFRC style U, SHGC, VT, and CR as one of standard outputs. The new shared module is planned for inclusion in the next release of EnergyPlus.

EnergyPlus does use thermal part of WINDOW engine for calculation. When using "standard" windows, EnergyPlus will use engine that is bit old (implemented around 2000), while using BSDF type of windows will use newer engine that is implemented around 2012. That engine does have SHGC and U-value calculations and that is reported in EnergyPlus output. However, report is only per windows construction and not for every window in a building. So if entire building uses same window construction then you should have only one window in report.

You should have U-value report only for certain constructions (center of glazings) and not for every window in the building. U-value of a window plus frame is not reported (and not calculated as such), however, I would need to check if that report is actually not part of eio file, but at a moment I am 99.99% sure that it is not. Note that U-value of COG is calculated by using standard NFRC conditions and not conditions from weather file that are used in simulation.

You should see the biggest difference with shading devices that redirect light. Lets say your shading device redirects light towards the floor and floor is highly absorptive compared to other surfaces. Then you should expect much bigger solar gain compared to standard approach. With specular systems, you will not see big difference. So it is all good.

BSDF is used for optical calculations. It will distribute solar and optical properties in a way it is described in BSDF matrix. It will not have huge influence on thermal except that will have little bit different solar distribution inside the room and therefore will have some influence on thermal flow through the window. Note that BSDF will have most of the impact on daylighting calculations and you should get illuminance distribution that is quite different than split-flux method. Speaking of BSDF, the most important improvement should have been seen in windows with shading devices.

Is pleated shade created by XML or in some other way? Same like in upper post. Check if you have data for back transmittance and reflectance. They cannot be zero or otherwise program will not converge since it non-physical case.

Any chance to get file that W7 created? Or even better, what window construction did you use in W7?

Did you use WINDOW 7 to create IGU?

It depends what you want to compare and in what way? If you want to compare energy transmitted through the window then solar transmittance is definitely not the only parameter that is needed.

Hi,

let me answer to some of your questions.

Where do patches start and end? Regarding to where patches start and end:

Center angle (we call it theta) is in degrees. Now, for standard basis you would get this (pay attention that first patch is not from 0 to 45 but rather from -22.5 to 22.5 - talking of phi angle here):

I suppose this would answer you question on how pathces are created?

Also, in what unit are these values in the 2d matrix of e+?

As for use in BSDF there are no units except for description of theta angle which is given in degrees.

Are there any other things i should consider using this approach?

Need more details on what exactly are you doing. In general, BSDF should give you pretty much correct results. Pay attention that daylighting model is single-bounce. So no multiple ray bouncing. Everything that goes through BSDF window in EnergyPlus will hit some surface and then will be bounced as perfectly diffuse.

How large can the matrix be to get reasonable runtime?

Go ahead and play with it. We are generally using standard basis (matrix that you exactly described above). However, you are not limited to this. One problem is that WINDOW 7 that is often used to create does not support yet anything that is not standard. It have only: quarter, half and full (standard) basis. Hopefully, that will be changed in near future.

Is it possible to have asymmetric matrices?

No. That is of course possible, but not implemented either in EnergyPlus nor in WINDOW.

Is it possible to treat direct and diffuse separately?

There should be some variables in EnergyPlus that should give you what is coming from diffuse and what is coming from direct beam. Just run it once and take a look at rdd file. That file contains all possible output variables for a given simulation. Once you find desired variable, you still have to insert it into IDF file.

Hope this helps.

Simon

Hi,

I can help you with this problem. First of all can you tell me what version of EnergyPlus did you use? I would also like to see window model that you have created by using WINDOW 7 and which weather file you have used in you simulation?

Thanks, Simon

UPDATE: Have you tried to do calculations in WINDOW 7 for this system? Seems that you are missing data for back transmittance and reflectance (shading device). Is it safe to assume that your shading device is symmetrical? So if it is then you can just copy/paste yours front measured data into back transmittance (and reflectance) and then perform the simulation. Of course, edit data in WINDOW 7 and then generate IDF in WINDOW 7.

Yes you can. Take a look at Construction:ComplexFenestrationState in Input/Output reference. I would highly recommend to use LBNLs WINDOW software to generate IDF for the window.

One way to model operable windows is to use Energy Management System. You can set-up several constructions for windows and then vary between them according to certain physical values. You can find manual in EnergyPlus installation folder under Documents/EMSApplicationGuide.pdf