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Michael Wetter edited this page May 20, 2020 · 3 revisions

SOEP Coordination meeting

Date: May 20, 2020, 8:15am-9am Pacific Times

The purpose of this meeting is to coordinate the Modelica integration for SOEP.

Meeting information

Join from PC, Mac, Linux, iOS or Android: https://lbnl.zoom.us/my/mwetter

Or iPhone one-tap (US Toll): +14086380968,6614042296# or +16465588656,6614042296#

Or Telephone:
Dial: +1 408 638 0968 (US Toll) or +1 646 558 8656 (US Toll) Meeting ID: 661 404 2296 International numbers available: https://lbnl.zoom.us/zoomconference?m=_h5BuJ686mPy3rWEyKf4NROxLaeOV5J8

Agenda

  1. Previous action items.
  2. Kyle, Michael: Refactoring room air heat and mass balance.
  3. Kyle, Michael: EnergyPlus I/O variables.
  4. Michael, Kyle: Support for radiant systems.
  5. Stuart: FMI-QSS.
  6. Kyle, Michael: Optimica license protection.
  7. Jianjun: JSON representation for OS front-end to Modelica
  8. Other items

Participants

Kyle Benne
Jianjun Hu
Stuart Mentzer
Joshua New
Hubertus Tummescheit
Michael Wetter

Minutes

Numerical investigations

This needs analysis of a Modelon staff who can look into the solver.

Refactoring room air balance

Branch issue1129_energyPlus_zone works for multiple buildings for JModelica, Dymola and OpenModelica.

Issues are at https://github.com/lbl-srg/modelica-buildings/issues?q=is%3Aissue+is%3Aopen+label%3Aspawn

Next, work on

  • Kyle to correct wrong radiation temperature, https://github.com/lbl-srg/modelica-buildings/issues/1954
  • Michael to add validation for schedules and EMS actuators, https://github.com/lbl-srg/modelica-buildings/issues/1633
  • Kyle to provide description for user guide for how warmup works.
  • Kyle to provide list of supported output variables, and statement of how non-supported output variables are handled, https://github.com/NREL/Spawn/commit/e443d634ab4f15d5d69e487fcc206c7d4f403353
  • Michael/Milica to use thermal zones in larger model, https://github.com/lbl-srg/modelica-buildings/pull/1663
  • Kyle to remove model.spawn. It has the same information as ModelicaBuildingsEnergyPlus.json (other than that some path are absolute and some are relative in model.spawn).
  • Kyle to look into generating all outputs in the folder tmp-simulation-TwoIdenticalZones. Also avoid multiple copies, for example, tmp-simulation-OneZone.building has most files twice, including the binaries (total 183 MB). Kyle will add a flag to be used to specify the output file directory.
  • Kyle to look into numerical instability (walls may be initialized to wrong temperature). See for example Experimental/EnergyPlus/Examples/VAVReheatRefBldgSmallOffice/FloorOpenLoop or Experimental/EnergyPlus/Validation/OneZone and set the initial room temperature to 10 degC.
  • Kyle and Michael to work out how to filter level of info/error/fatal errors. See code near

const size_t nCat = fmi2_import_get_log_categories_num(bui->fmu); * Kyle to create installer package for all three platforms.

Need to refactor to freeze room air temperatures at initial temperature as requested from Modelica. Rooms not in Modelica will do warm-up to compute their room temperature. Warm-up stops when all inside-facing surface temperatures stabilized at mid-night in all rooms, whether present or not in Modelica.

Actuators and schedule should work on the EnergyPlus side.

Goal is to have a Buildings library release with Spawn before the peer-review.

Kyle to work on emitting all EnergyPlus objects that are supported by Spawn.

Contract:

  1. If there is a thermal zone in Modelica, then there need to be a Zone object in the idf file. Otherwise the simulation stops with an error. EnergyPlus reports a Fatal Error to its error file and to the FMI API call.
  2. If there is an Zone object in the idf file but no thermal zone in Modelica for this EnergyPlus zone, then EnergyPlus simulates the zone using free floating temperature. There is no HVAC system, but may be internal gains. EnergyPlus reports an information message to its error file and to the FMI API call.
  3. All HVAC objects in the idf file will be removed by the Spawn executable before it writes the idf file to the FMU.
  4. For the EnergyPlus envelope, either the CTF transfer function or the finite difference method can be used.
  5. Output variables and EMS actuators need not be present in the idf file.

Radiant systems

Posted specification.

Kyle to review specification.

FMI-QSS

Stuart to work on small example with time events (sampler) and with reinit. Need updated OCT distribution.

Decide when to update output variables that have no state dependency.

u = if t > 1 then 1 else 2;
s = 2 * u; // local variable, not reported at a QSS step
dx/dt = s-x;

Output variables:

s = 2 * u;
y = 2*x;

Make evaluating all internal (non-output) variables an optional flag at discrete sample times (say 2 minutes), and then benchmark using a large model to see the cost.

Optionally, allow all variables to be reported at each QSS step inside a user specified time interval.

CI testing (funnel)

No discussions.

Next:

  • Work on experiment specification.

OS X

Included in this year's NREL contract. Support for Spawn on OS X (won't include the optimization and other Modelon libraries).

Optimica license protection

No discussion, waiting for NREL contract.

Potential paths: Modelon shared initial proposal.

JSON representation for OS front-end to Modelica

Enabled installation and run on Windows OS. Fixed failed parsing due to the DynamicSelect.

To do:

Other items

None.

New action items

Michael to move Modelica/EnergyPlus related open issues to Buildings Library repository issues for easier tracking.

See next steps under "Refactoring room air balance".

Previous action items

Michael to keep working with Modelon on making dp of pressure drop elements a state rather than p using stateSelect.

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