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2022 12 13 coordination
Date: December 13, 2022, 8am-9am Pacific Times.
The purpose of this meeting is to coordinate the Modelica IBPSA Working Group.
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
Miscellaneous
PV collector, battery and electrical component models (Laura Maier)
Modular heat pump (Fabian Wüllhorst)
Fan efficiency based on Euler method (Hongxiang Fu)
Creation of reduced order building models (Alessandro Maccharini)
New state selection (Michael Wetter)
Equivalent borehole g functions (Massimo Cimmino)
Weekly schedule (Michael, Dre)
Progress on pull requests, https://github.com/ibpsa/modelica-ibpsa/pulls
Michael Wetter, Ettore Zanetti, Christoph Nytsch, Alessandro Maccarini, Dre Helmns, Fabian Wuhllhorst, Filip Jorissen, H. Casper Fu, Jelger Jensen, Kathryn Grace Hinkelman, Laura Maier, Liu Mingzhe, Wei Mingjun.
Suggested new structure with 15 min presentation at beginning.
Laura Meier presented work done on electrical package for IBPSA library.
The package takes inspiration from Buildings electrical package developed by Marco Bonvini and expands on it.
Main features:
General replaceable connector (DC,AC one phase, AC two phases,...).
There are two main model packages one for DC and one for AC. Some models could be mode replaceable, but two separate packages were chosen for the sake of readability by the user.
PV model and Wind turbine model introduced as sources for DC package.
Two PV models were developed and validated from IEEE use cases. One is a 1 diode model and the other a 2 diode. They are a mix of physical and empirical models to make the equations simpler for the solver. Validation examples are present in Validation.PVSingleDiodeNISTValidation . Christoph is also planning to create a PV test bench in Aachen RWTH, where more validation cases could be created.
The PV model is structured in three different replaceable sub components (swap IV curves, mounting types for heat transfer correlations, radiation models)
Q&A:
Question 1: PV parameters available on datasheets? It may be useful to derive physical parameters starting from datasheets available parameters.
Answer: Single diode models can be parametrized with datasheets. two diode models cannot be directly parametrized. It would be useful to develop a database of pre parametrized models to choose from.
Question 2: Why weatherBus was not used?
Answer: Not all libraries use the weatherBus. Therefore in this way the model could be used by everyone. However, an additional wrapper should be added in libraries that do use the weatherBus (maybe use conditional components for lat and lon definitions)
Questions 3: Connect heat pump with PV (electrical coupling)?
Answer: Use-cases may not justify the model complications. Using Voltage and current instead of power would imply introducing power factor into the equations and new control issues (i.e. if control signal is 100% do power draw = 100% from line or I consider Voltage = 230 and power draw = electrical balance). One suggestion was to design models using the same approach as for pumps/fans by changing the causality of the equations.
https://github.com/ibpsa/modelica-ibpsa/pull/1628.
Fabian is implementing 5 examples using the heat pump in different configurations. Should be done by Christmas and then ready for review. Michael and Fabian need to discuss offline about the bus connections.
https://github.com/ibpsa/modelica-ibpsa/pull/1646 Casper presented updates on the fan model and in particular on the efficiency calculation.
Q&A
Question1: Care should be taken for default curves because smaller pumps/fans (residential) have much lower efficiencies with respect to their bigger commercial counterparts (would be interesting to add).
Question2: Issue with motor efficiency around 0 (No load), problem with spike in power?
Answer: Still unresolved (regularized for now). One proposal is to actually model the motor instead of using curves, but it would complicate the equations.
Question3: What if we want to use our own efficiency curve?
Answer: This new model is just a wrapper, so the old one with the per parameter exposed will be still available.
https://github.com/ibpsa/modelica-ibpsa/pull/1627
Alessandro is still working on review comments. The main one remaining is about surface vectorization. After that it will be ready for merging.
Nothing conclusive. Working on it with Dassault, Modelon and OpenModelica. Running on some issues on the solver side.
https://github.com/ibpsa/modelica-ibpsa/issues/1412
https://github.com/ibpsa/modelica-ibpsa/pull/1623
Massimo was not present at the meeting.
https://github.com/ibpsa/modelica-ibpsa/pull/1602
Move forward with merge (requires new OpenModelica image from Michael, to be done soon as 0/0 divison in OMC is about to be fixed).
Hot water profile from Dre still not ready yet.
- Anyone presentation to share?
- Dre to provide Data package for new weekly schedule object (
IBPSA.Utilities.IO.Files.WeeklySchedule).
Nov 2022: Dre to provide Data package for new weekly schedule object (IBPSA.Utilities.IO.Files.WeeklySchedule).