What an interesting discussion. By now I'm working in my PhD and this question -how I could integrate illuminances with solar heat gains through windows- has been one of the hardest things.
Firstly, because when I simulated my models there weren't some tools like DIVA or OpenStudio, or the were starting, so I decided to duplicate the simulations: every model has been calculated with DAYSIM for getting the illuminances for each time step throughout a year, and has been calcualted with DesignBuilder (EnergyPlus) for getting the solar heat gains for the same time step and period. I think you can do as I did with OpenStudio and Radiance.
Secondly, how to integrate both results. Illuminances are given for every sensor and Solar heat gains are given for the whole thermal zone; one is punctual and other is volumetric, so I decided to treat every measure in order to find a common place to be compared and integrated.
So I think the question is not if the programs are coupled or could be coupled (anyway, every engine is design to calculate different aspects so soon or later they will work "together"), the key question is to obtain measures for the same climatic conditions, period, time step (these three are conditions are now able to achieve) and, very important, dimension.
Hope to be able soon to show you how I treated those measures.
···
Date: Tue, 11 Mar 2014 17:19:57 -0400
From: [email protected]
To: [email protected]
Subject: Re: [Radiance-openstudio] Solar Heat Gain Coefficient (SHGC) Calculations in OpenStudio's Coupled Radiance and EnergyPlus Simulations
Thank you for the response everyone, I appreciate your time and efforts. Sorry to ask such a non-straightforward question.
Hello Denis,
Diva4Rhino is actually a tool I've used for solar analysis in the past. It's a really cool tool, especially since I've seen a lot of grasshopper use in architecture practice lately. Unfortunately, the radiation maps are not what we're looking for because we're trying to apply the result to the interior heat gain of the building. I believe Diva has some functionality for determining the solar heat gain to the interior, because I remember using in the past, but for my current project I don't believe its robust enough.
Thank you, I'll look into ESP-r and see if it's something that can apply.
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Hello Rob,
No problem at all, I landed on the page from a google search and didn't notice the subscribe button from the radiance page. Andrew was very helpful.
The EnergyPlus lighting load schedule, generated from the Radiance daylight simulation, makes sense to me. It's really awesome that you made those calculations so streamline. I do whole building simulation in an architecture graduate program and I can already see how it would be applied in many design applications. Though, I'm a bit confused how the solar heat gain is effected from the OpenStudio model, with Radiance turned on.
How does the coupled Radiance and EnergyPlus method impact the solar heat gain calculations in EnergyPlus (if at all)? In other words, if two identical buildings were modeled, one with a CFS and Radiance and one without, would the CFS OpenStudio model have a reduced solar heat gain? Is the BSDF applied somewhere in the EnergyPlus model to determine new solar heat gain values or through Radiance? If so, maybe you can elaborate on how it's applied. Is the reduced solar heat gain due to the modules in EnergyPlus or a data flow between Radiance and EnergyPlus?
You guys are doing awesome stuff at NREL with OpenStudio. I look forward to seeing where it goes in the future. Whole building simulation has been my research interest in my PhD. Through my research, I hope to gain an advanced understanding of what's going in whole building simulation and contribute to the field someday.
Sorry if my questions are a bit confusing. I tried asking the same question in a couple different ways in the hope that one of them is clear.
Thank you,Justin Shultz
PhD Student
On Tue, Mar 11, 2014 at 4:14 PM, Guglielmetti, Robert <[email protected]> wrote:
Hey Justin, welcome, and sorry about the list subscription snafu!
So, let’s see. German is right, in its current form. OpenStudio uses Radiance to do an annual daylight simulation, and runs a tool called mkschedule.rb to generate electric lighting load schedules based on the occupancy schedules and daylighting controls (and setpoints) in the OS model, and the daylight availability as calculated by Radiance. These schedules are then put back onto the OpenStudio model which is then passed to EnergyPlus, which does all the solar thermal stuff on its own. Somewhat convoluted and unfortunately linear, but all managed automatically for you by the OpenStudio application.
We (and others) are using the OpenStudio API to write little helper programs to link things a little bit better, so that BSDFs can be used to model CFS, dynamically, and some of these efforts are currently being integrated in to the OpenStudio application as we speak. In the very near future, a user will be able to assign generic shades to any window or series of windows in your OpenStudio model, and select from a number of the shade control algorithms available in EnergyPlus; OpenStudio will then perform a so-called dynamic daylight simulation of the model both in Radiance (for the daylighting) and E+ (for the thermal); all the shading controls are automatically applied to both the Radiance and EnergyPlus models.
Initial support for this will be rolled out in the next month or so, and will use generic BSDFs that we will either include in OpenStudio or make available via the Building Component Library. Down the road, we will allow the user to specify arbitrary BSDFs and apply them to both the Radiance and EnergyPlus models.
- Rob
From: Justin Shultz <[email protected]<mailto:[email protected]>>
Reply-To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>
Date: Tuesday, March 11, 2014 at 1:06 PM
To: "rad[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>
Subject: Re: [Radiance-openstudio] Solar Heat Gain Coefficient (SHGC) Calculations in OpenStudio's Coupled Radiance and EnergyPlus Simulations
I've heard some things about Radiance solar heat gain calculates but haven't found any papers on how to integrate it within a whole-building simulation yet, I'll keep looking. If anyone knows of a source it would be extremely helpful.
EnergyPlus does have a nicely integrated venetian blind module, but unfortunately that doesn't exactly represent the system we're attempting to model. My project is similar but a bit more complicated in practice, although it does also block direct beam, I'll need to think if this is representative. We were imagining, creating a defined number of geometries (representative of dynamic states), create the BSDF for each, and then chose between them for various states of the annual daylight simulation.Following the three-phase method, with the integration of results in a whole-building simulation.
From your suggestions, it appears as though the best solution to calculate the solar heat gain would be to integrate a BSDF in EnergyPlus. Use E+ to calculate the solar heat gain and then use Radiance (with OpenStudio) for the Daylight and Lighting Load simulations. Though I'm guessing that EnergyPlus cannot handle dynamic BSDFs for various CFS configurations without some form of co-simulation. I'll have to read more into the methods EnergyPlus uses to calculate the solar heat gain from a BSDF and determine if that meets my criteria.
Does anyone know of any articles or publications that discuss advanced methods for integrating Radiance daylight and heat gain into whole-building simulation from dynamic fenestration systems? Maybe I'm looking at the problem from the wrong perspective.
Thank you German, I look forward to receiving your thesis. I watched your SketchUp plug-in video earlier, very cool stuff.
Sincerely,
Justin
On Tue, Mar 11, 2014 at 2:33 PM, Germán Molina Larrain <[email protected]<mailto:[email protected]>> wrote:
Although I have heard some things about calculating solar heat gains with Radiance, I do not think OpenStudio does that... I did not do that, at least.
EnergyPlus allows modelling simple glazing, Venetian Blinds, shades and other shading devices, and also inserting the BSDF of a CFS, and it will calculate the solar heat gains. My understanding is that the BSDF-based modelling of a CFS will be accurate enough for performing the calculation... maybe Radiance would be better for more complex handling geometries and materials though.
I also understand that VenetianBlinds, as defined in EnergyPlus, allow you to choose a "block beam radiation" algorithm. I guess that, from that, you can report the VB position, and perform the lighting simulation in Radiance, and choose the artificial lighting power for the luminaires, and write them down in a schedule. Finally, you can go back to EnergyPlus, and use the lighting power, and use it to control the internal gains caused by the artificial lighting. THIS WOULD BE VALID FOR THIS CASE. In my thesis you might find how to do it with some other kind of shading device.
I will attach my Thesis directly to you later.
Bye!
Germán
2014-03-11 15:11 GMT-03:00 Justin Shultz <[email protected]<mailto:[email protected]>>:
Hello German,
Thank you for the quick reply. Yeah, that's my understanding of the daylight contributions and the mkschedule.rb code. The part that I don't understand is if the OpenStudio simulation of Radiance and EnergyPlus calculates the new solar heat gain (of the CFS) using Radiance or EnergyPlus, if at all.
Let's use a dynamic venitican blind as an example, ones that track the sun's altitude. The intercepted solar irradiance will block some direct sunlight and solar heat gain. The part I'm unclear about is how to implement (if it's not already) the interception of solar heat gain from directly entering the thermal zone modeled in EnergyPlus. If OpenStudio does this already, maybe I'm just missing it and someone can point me in the right direction. If it doesn't, is there a tutorial that goes over Radiance daylight and solar heat gain simulations and how they plug into EnergyPlus. Also, the limitations of using said method.
If you don't mind sharing, I think your thesis would be very helpful in understanding how to apply thermal and daylight simulations to an EnergyPlus simulation.
Thank you,
Justin
On Tue, Mar 11, 2014 at 1:57 PM, Germán Molina Larrain <[email protected]<mailto:[email protected]>> wrote:
Justin,
What do you mean with "transforms the solar heat gain"? The last thing I heard is that OpenStudio uses Radiance to calculate the Daylight contribution, and choose the Artificial Lighting power in each zone, using a script called MKSCHEDULE. EnergyPlus, then, will have to calculate Solar Heat Gain by itself, and the luminaire power will be defined from a Schedule created with the MKSCHEDULE script.
On the other hand, I worked on that topic during my M.Sc. Thesis, working with integrated Thermal and Lighting simulations of spaces with controlled Luminaires and Complex Fenestration Systems. I used Radiance and EnergyPlus, but no OpenStudio. You (and anyone) can ask me for my thesis, or related information.
I wanted to contribute to OpenStudio, but my programming skills and lack of time did not allow me.
Bye!
Germán
2014-03-11 14:42 GMT-03:00 Justin Shultz <[email protected]<mailto:[email protected]>>:
Hello Radiance and OpenStudio users and developers,
I'm new to the radiance and daylight simulation. Sorry if this is a basic
question. I have used EnergyPlus for many basic projects, but my most recent
one is studying a dynamic glazing system. My partner and I have determined
that the three-phase method is probably going to be our best option. We're
looking to model the effects the dynamic glazing system would have on the
electrical lighting loads, as well as, the solar heat gain into the building
zone.
I've been reviewing the tools and methods at are currently available to do
this and found "Challenges of Integrated Daylight and Electrical Lighting
Simulation Methods in a Whole-Building Energy Simulation Context" by Rob
Guglielmetti to be tremendously helpful. OpenStudio appears to be one of the
most integrated and streamline options available for coupled daylight and
whole building simulation.
The question I have, that I haven't been able to find, is whether the
OpenStudio coupled Radiance and EnergyPlus method transforms the solar heat
gain? The daylight is well studied and discussed, but I haven't been able to
find out whether this method will discount the solar heat gain through the
fenestration systems.
Additional side question: When running genBSDF is there a command or
something material property that needs to be added to get the factors for the
SHGC? We have only been able to get the daylight coefficients.
Thank you for your help,
Justin Shultz
PhD Student
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