[Bldg-sim] 100 simulations

Thu Sep 10 14:33:48 PDT 2015

Aaron and Jason, I like this thread. I noticed that the curve Aaron
presented for WWR vs. Source Energy shows only a 4% difference in Source
Energy over a range of 0-50% WWR---I would say a negligible difference from
optimizing this component alone. An architect would shrug this off, despite
the thought and computing power that went into it. This got me to thinking
that, as an architect, the aspect my colleagues most have trouble with is
the arrangement of building elements, rather than the optimization of each
one.

Jason's questions related to arrangement---how many floors? what shape
building?---would be the most useful for conceptual design, in my opinion.
I would leave alone insulation levels and even WWR at the
programming/conceptual stage, and instead run hundreds of simulations with
different *arrangements* of zones. I would further clarify this point by
adding to Jason's questions list:

1. Does the conference room go on the east or west (re: sun exposure)?
Under the roof, or in the basement?
2. How deep can floor plates be, and still achieve adequate daylighting?
3. What aspect ratio of the atrium vs. the floor plates gives us adequate
natural ventilation?
4. If I put the fume hoods in the classroom, I have to ventilate the whole
classroom, but if I put them only in prep rooms, that is a much smaller air
volume...what difference does this make?
5. If I cluster all my public circulation to one side, and naturally
ventilate this, how much energy do I save vs. distributed circulation that
is conditioned with fans?
6. Add a giant, beautiful glass staircase---do I save enough elevator
energy to offset the conditioning of the staircase?

In typical optimization modeling, the geometry is fixed and we vary the
component parameters. I'd like to see the opposite.

If the auto-generating algorithm could produce a 3D mass diagram of
color-coded zone blobs, perhaps as a Sketchup object, that would
communicate well.

Again, architects tend to have trouble with the spatial arrangement of
zones as something driven by performance. Perhaps the most useful thing at
the programming/concept design stage is help with arrangement. Thank you,
Dan J

Dan Johnson | Design and Energy | 510.325.5672
Assoc. AIA, ASHRAE, LEED AP, CEPE, CPHC | 907 Ramona Ave. Albany California
94706

> ---------- Forwarded message ----------
> From: Aaron Powers <caaronpowers at gmail.com>
> To: Jason Glazer <jglazer at gard.com>
> Cc: bldg-sim at onebuilding.org
> Date: Thu, 10 Sep 2015 12:46:16 -0500
> Subject: Re: [Bldg-sim] 100 simulations
> Jason,
>
> This is something I'm interested in as well.  I think all the preliminary
> design factors that you mentioned are great things to look at.  On the
> later parts of the design process, control parameters are also good things
> to look at (CHW plant control optimization, air-side control optimization,
> etc.).
>
> One way to convey the information is through simple 2D plots.  Below is an
> example of 200 DOE2 simulations while varying the window to wall ratio and
> another plot of 81 simulations varying the window shading coefficient.
>
> [image: Inline image 1][image: Inline image 2]
>
>
>
> Unfortunately, this does not convey the interactive nature of optimization
> over multiple variables.  Using multidimensional optimization algorithms
> can be another useful tool, but they can be tricky.  As an example, below
> is a case of looking for the optimal minimum condenser water flow in a
> variable flow condenser system.  From looking at the first plot, the
> function seems relatively smooth and it's obvious that there's an optimal
> in the neighborhood of 0.6.  However, if you zoom in (second plot), you can
> see that the data is not very smooth, and there are all kinds of jagged
> local minima/maxima.  These will tend to throw off most optimization
> algorithms, which is why I think it's helpful to consider looking at
> automated mass simulations before taking on the problem of optimization.
>
> [image: Inline image 5]
>
> [image: Inline image 4]
> Aaron
>
> On Wed, Sep 9, 2015 at 4:33 PM, Jason Glazer <jglazer at gard.com> wrote:
>
>> I am just finishing up a project that performed about 60 automated
>> simulations (using Python with EnergyPlus and Eppy) for a series of
>> buildings in a bunch of cities. The power of automating simulations to
>> understand the energy savings of different measures is very impressive no
>> matter what tools are being used.  It has made me wonder about when does
>> automation make the most sense during the design process and what
>> information can be provided to an architect or entire building design team
>> to encourage low energy building design.  I am thinking one of the most
>> influential times might be during the architectural programming and early
>> conceptual design steps. At this point the number of separate pieces of
>> information is probably low enough that it could be filled out on a web
>> form:
>>
>>  - number of occupants
>>
>>  - amount of area needed for different types of spaces
>>
>>  - location of the lot lines
>>
>>  - building location
>>
>> Conceivably, with that information, all sorts of various building
>> configurations could be created automatically by a clever script then
>> simulated and the resulting answers summarized.
>>
>>  - How many floor building uses the least energy?
>>
>>  - What shape building uses the least energy?
>>
>>  - What is the impact of more roof insulation?
>>
>>  - What is the impact of more or less fenestration on loads and
>> daylighting?
>>
>> I would not expect the design team to use any of the automatically
>> created building models directly but it might influence the design process
>> in a good way if it was easy to get and easy to understand. I understand
>> people have been researching the optimization of these kinds of factors but
>> I am not sure that is necessary. Maybe just several different series of
>> simulations illustrating various building options and their impact onenergy
>> might be enough to get the discussion going.
>>
>>  - So what questions do you think could be answered by such an automated
>> system during early conceptual design?
>>
>>  - How would you best convey that information to the building design team?
>>
>>  - Are there other times that a suite of automated simulations would make
>> sense?
>>
>> A lot of useful information could be generated with a hundred automated
>> simulations!
>>
>> Jason
>>
>> --
>> Jason Glazer, P.E., GARD Analytics, 90.1 ECB chair
>> Admin for onebuilding.org building performance mailing lists
>>
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>
>
>
> --
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>
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