[Radiance-openstudio] Solar Heat Gain Coefficient (SHGC) Calculations in OpenStudio's Coupled Radiance and EnergyPlus Simulations

[Justin Shultz]

Thank you for the responses everyone. This has been extremely helpful.

Paula,

I look forward to reading your thesis, sounds very applicatable. I agree, I
think the method that I will need to use will be to tie a Radiance
simulation to EnergyPlus. The trick will be figuring out how to transform
the Radiance result to EnergyPlus input.

------

Rob,

Thank you for your thorough response. Im excited to see where OpenStudio
goes and how it get integrated into the design process. The features you
guys are integrating and streamlining will be really fun to test out in the
future. Unfortunately, I'm going to need more control over the BSDFs
selection and control. This project is also on a short(ish) deadline.

It appears as though to model a custom, dynamic CFS I am going to have to
use the radiance 3-phase simulations and manually tie the results into
EnergyPlus with a schedule and maybe (EMS for the solar heat gain). The
3-phase method seems to be the best method for this so I'm going to have to
read up on that process.

I found "The Three-Phase Method for Simulating Complex Fenestration with
Radiance" tutorial by Andrew McNeil. It looks like a good place to start
but the disconnnect in my head is how to take the annual simulation results
and convert them to a schedule for EnergyPlus. There are a couple programs
that do this already, like DAYSIM and OpenStudio, but I haven't figured out
how to do it manually. Does anyone have any material on how to manually
convert Radiance results to an EnergyPlus schedule?

I've been reading through German Molina's thesis, which has been very
helpful so far. I was wondering if there are any tutorials (over tips) that
step someone through how to convert Radiance result to an EnergyPlus
schedule? I thought there might have been a module in Radiance that did
this but I haven't been able to find it.

Thank you for the help everyone, I really appreciate it. Sorry to keep the
chain going for so long. I hope this is benefitial to others too!
Justin Shultz
PhD Student


On Thu, Mar 13, 2014 at 12:21 AM, Guglielmetti, Robert <
Robert.Guglielmetti at nrel.gov> wrote:

> Hi Justin, a couple of answers below, inline (prefixed with "***RPG:")
>
> - Rob
>
> From: Justin Shultz <jss5237 at gmail.com<mailto:jss5237 at gmail.com>>
> Reply-To: "radiance-openstudio at radiance-online.org<mailto:
> radiance-openstudio at radiance-online.org>" <
> radiance-openstudio at radiance-online.org<mailto:
> radiance-openstudio at radiance-online.org>>
> Date: Tuesday, March 11, 2014 at 3:19 PM
> To: "radiance-openstudio at radiance-online.org<mailto:
> radiance-openstudio at radiance-online.org>" <
> radiance-openstudio at radiance-online.org<mailto:
> radiance-openstudio at radiance-online.org>>
> 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.
>
> ----------------------------------------------------------
>
> 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.
>
> ***RPG: Yes, Andrew generally is. =8-)
>
> 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?
>
> ***RPG: Great question(s). We are implementing using BSDFs on the Radiance
> side to model shades, blinds, and diffusing glass, in a general way. All of
> these things can also be modeled in EnergyPlus. The plan is to upload a
> library of generic BSDFs describing:
>
> 1. Clear glazing (1-91% VLT)
> 2. Clear glazing with venetian blinds (slats preset to something
> aggressive, and blinds fully extended, i.e. covering the entire window)
> 3. Clear glazing with shadecloth material (5% openness, fully extended)
> 4. Diffuse glazing (1-70% VLT)
>
> These BSDFs all correspond to various EnergyPlus Construction
> Assembly.Fenestration.Window elements or material properties. We also have
> exposed several of the EnergyPlus shade control options:
>
> 1. Always on (down)
> 2. Always off (up)
> 3. Operate by schedule (user-supplied)
> 4. On if high solar
>
> The user applies shading controls to one or more windows in the OpenStudio
> model; at run time the OpenStudio-to-Radiance translator will map the
> appropriate BSDF pairs to each window group (windows sharing orientation
> and shading control) so that the daylight availability will be calculated
> by Radiance, and will be based on user-specified operable shades and
> control. After that, OpenStudio works like it always has during a Radiance
> simulation: the electric lighting schedules are computed, and passed back
> to the OpenStudio model, which then computes the building energy use with
> EnergyPlus.
>
> In other words, it's still a serial process, where Radiance goes first and
> does a daylight simulation, thus informing the electric lighting operation,
> which is passed to EnergyPlus for the rest of it. It's integrated, but
> could hardly be called "cosimulation". Not yet, anyway.
>
> Hopefully this all makes sense. (?) We hope to release all of this
> functionality in the next couple of months.
>
> - Rob
>
>
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