[Bldg-sim] "Maslow's" hierarchy of calibration

[Julien Marrec]

Hello Chris,

Apologies if I didn't understand the question correctly, but I understood
it as how to automate (part of) the calibration process.

I don't think you should do without first taking a hard look at your
initial model, refine it until almost satisfied, before you can start the
calibration process itself. One example would be you should probably take a
close look at your output:variables to ensure that you are supplying the
right amount of outside air to your zones.

I also don't think you should blindly let some tool touch *any* parameters
there are in your simulation file. There are things you can measure or
reasonably approximate, and those should be defined in your model. Then
there are things that are hard to guess, or hard to guess right, and those
should be what you play on.

These caveats aside, there are a number of tools and algorithms that can
help you automate the calibration process itself.

One example of such is LBNL's GenOpt
<https://simulationresearch.lbl.gov/projects/genopt> which is software
agnostic (a front-end for it that I have used in the past with both eQuest
and EnergyPlus is ExcaliBEM, from Canada's SIMEB, not sure if still out
there or not)

You basically inform the software of the parameters you want to vary and
how (for eg, infiltration from 0.3 to 1.0 ACH, R-value +- 30%, heating
system efficiency range, etc), and define an objective function, which can
be a python script. I've done one that basically tries to minimize the
CV(RMSE) and NMBE %, and penalizes heavily if not meeting the thresholds of
Guideline 14. The tool will run simulations and try to minimize the
objective function.

The OpenStudio Analysis Framework
<https://github.com/NREL/OpenStudio-server> is a great candidate if you're
working with the OpenStudio ecosystem.

JEPlus+EA <http://www.jeplus.org/wiki/doku.php> can do that for EnergyPlus
(and is (was?) bundled in Design Builder if I recall correctly)

There are a variety of similar questions on unmethours.com

Best,
Julien
--
Julien Marrec, EBCP, BPI MFBA
Owner at EffiBEM <http://www.effibem.com>
T: +33 6 95 14 42 13

LinkedIn (en <https://www.linkedin.com/in/julienmarrec>) *| *(fr
<https://fr.linkedin.com/in/julienmarrec/fr>) :
<http://www.linkedin.com/in/julienmarrec>


Le mar. 23 juil. 2024 à 09:06, Chris Yates via Bldg-sim <
bldg-sim at lists.onebuilding.org> a écrit :

> Dear bldg-sim’rs,
>
>
>
> I’m interested in how people save time and improve accuracy when it comes
> to calibrated simulation.
>
>
>
> Calibrated simulation attempts to model a vast amount of parameters. In
> comparison to regression methods it’s completely overspecified. We do it in
> the hope of creating a model (a “digital twin”) that gives us many more
> what-if? scenarios than regression could on its own.
>
>
>
> However, the process is often fraught with dead ends. Of course it is!
> There are too many details. We can waste a lot of time on getting one
> parameter right, only to find it has little effect. Even worse, we could
> overlook something major and compensate with our own erroneous assumptions.
> Or, we can work through a whole model and find something very late on,
> causing us to backtrack over previous work. The act of calibration seems
> beyond detailed management because of the sheer number of building types,
> servicing approaches, operational parameters, embedded issues (this is a
> longer list but I’ve ran out of words…).
>
>
>
> The exam question is:
>
>
>
>    - Does anybody follow a simple high level framework (a bit like
>    Maslow) for calibration?
>
>
>
> Sorry. I could have asked that at the start of the email 😐
>
>
>
> All the best
>
>
>
> Chris
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