Specifically, my group is working on thermal modeling of EVs i.e cabin cooling and battery cooling. We have used most elements from the two-phase-fluid sub-library of simscape. But at two connections we want a controlled separation of the refrigerant flow. For that, there is an element called flow divider but it's in the hydraulics sub-library. So how do I use these libraries simultaneously? I'm trying since yesterday but nothings seem to work. Thank you.
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I have been working with Anylogic for about 6 months now and my goal is to model a generic energy supply chain for an energy demand (e.g. storm and heat for a house). As a result I want to evaluate how suitable the components in the energy supply chain are to meet the energy demand.
My idea would be to model the components (Ex. PV->Battery Storage->House) as agents. I would have modeled the energy flow in the agents with SD and individual events of the components (e.g. charging and discharging at the battery) via state diagrams.
Currently I have two problems:
Which possibilities are there to create a variable interconnection of my components (agents). For example, if I do not want to evaluate the scenario PV->Battery Storage->House, but PV->Electrolysis->Tank->Fuel Cell->House. My current approach would be to visually connect the agents with ports and connectors and then pass input and output variables for DS calculation via set and get functions. Are there other possibilities, e.g. to realize such a connection via an input Excel? I have seen a similar solution in the video: "How to Build a True Digital Twin with Self-Configuring Models Using the Material Handling Library" by Benjamin Schumann, but I am not sure if this approach can be applied to SD.
To evaluate the energy supply chain, I would like to add information to the energy flow, for example the type (electricity, heat), generation price (depending on which components the energy flow went through) and others. Is there a way to add this information to a flow in SD? My current approach would be to model the energy flow as an agent population with appropriate parameters and variables. Then agents could die when energy is consumed or converted from electricity to heat type. However, I don't know if this fits with the SD modeling of the energy flow.
Maybe you can help me with my problems? I would basically be interested in the opinion of more experienced Anylogic users if my approaches would be feasible or if there are other or easier approaches. If you know of any tutorial videos or example models that address similar problems, I would also be happy to learn from them.
Best
Christoph
Sounds like what you need is a model that combine agent-based and system dynamics approaches with Agents populating the stocks (in your case energy that then gets converted into heat) depending on their connection. There is an example of AB-SD combination model in 'Example' models and I also found one on cloud.anylogic.com, although it is from a different domain.
Perhaps if you can put together a simple example and share then I'll be able to provide more help.
In the Thermal Power Library from Modelon, there are two kinds of connectors: flow connector and volume connector.
Based on the tutorial shipped with the library, these two kinds of connectors should NOT be connected with the same kind of connector.
But I checked their code, it seems the codes are the same.
I checked the code in the ThermoSysPro library from EDF and ThermoPower library, too. They also use two kinds of connectors, and the recommendation of connecting principle is also the same.
So I read the code of “MixVolume” and “SteamTurbineStodola”, which include volume connectors and flow connectors respectively, but I am not sure the difference between these two kinds of connectors.
My question is :
Could someone tell me the philosophy of using such two kinds of connectors in thermo-hydraulic systems, and in the code of every component, how should I deal with them so they work like they’re designed for.
Here is a very short and simplified explanation applying to thermo-hydraulic systems.
In flow models (pipes, valves etc.) enthalpy is unchanged and mass flow/pressure drop are related with a static equation.
In volume models pressure and enthalpy are dynamic state variables, that is, mass and energy conservation is "elastic".
As a rule of thumb, you should build thermo-hydraulic system models of alternating flow and volume models (in a staggered grid scheme) to decouple nonlinear systems.
For the dynamic pipe model in the top figure in your post the connectors merely indicate that, internally, the pipe model begins with a volume model and ends with a flow model.
Claytex has a nice blog post on the subject here https://www.claytex.com/blog/how-to-avoid-computationally-expensive-fluid-networks-in-dymola/
Also the authors of the Modelica Buildings Library have done a great effort explaining this in various papers. See e.g. https://buildings.lbl.gov/publications/simulation-speed-analysis-and
These kind of connectors are indeed the same due to modelica language specification. You can only connect two connectors that are interchangeable, that have the exact same amount and type of flow and potential variables. At every node all flows have to sum up to zero and all potentials have to be the same, therefore they have to be type consistent.
The difference is just information wise for the modeler or someone trying to understand the model and all components have been designed with such a thing in mind. It is easiest to understand with electrical components, where you have positive and negative pins which indicate in which direction the current should flow, but this is actually never really forced. Positive and negative pins are, ignoring their name, identical.
Although i don't know the connectors you are talking about i would assume that the VolumePort is a connector of something that has a volume and passes that information, whereas FlowPort passes the information about the mass flow rate. Usually a pipe i guess (?). Broken down to abstract dae theory one could say the names indicate if the potential or the flow variable are considered unknown for the component.
I have to emphasize that these are only indicators and that it is never actually forced by the model or the compiler. It is just how it should logically resolve in the end if you respect these restrictions of only connecting VolumePortto FlowPort connectors.
i implement a network simulation in Simulink/SimEvents (2018b) containing a Ethernet bus, which consists of three different subsystems like shown in the figure.
The blocks send entities to each other. This results to a quite complex scene, i'd like to improve by changing the position of the ports (like input port and output port on the same side of the subsystem). I haven't found a way how to do it.
I hope someone can help me.
It's not possible. Inports and Outports are always positioned on opposite sides of the block, and cannot be changed.
The exceptions are trigger and/or enable ports, which appear on a side which doesn't have inports or outports - but they can't be changed either.
In early versions of SimEvents you could position inports and outports on the same side, however I believe that functionality was removed in about R2017a or thereabouts.
In your case you could rotate your Node block to tidy up those connections, but there's nothing you can really do with the other signals crossing each other. (You could use GoTo and From blocks, although I'm not a fan of doing that.)
For Matlab simulink, how does one go about generating multiple step function at different conditions for a system
I am trying to simulate a simple flow through a tank and controlling the temperature within. At various interval say time at 10ses and 20secs i intend to draw out different flowrate/flow amount of water.
With the system designed, how do I show on a single scope how Flow in changes with the different amount of flow out drawn.
Appreciate any kind advises
There are many different ways of doing this, for example defining the data in MATLAB and using a From Workspace block or using multiple Step blocks summed together appropriately. But to start I'd suggest you look at the Signal Builder block.
To view multiple signals at once in the same Scope, either set the scope up to have multiple inports, or Mux the signals together and feed them in in the usual way.
I'm trying to evaluate an application that runs on a vehicular network using OMNeT++, Veins and SUMO. Because the application relies on realistic traffic behavior, so I decided to use the LuST Scenario, which seems to be the state of the art for such data. However, I'd like to use specific parts of this scenario instead of the entire scenario (e.g., a high and a low traffic load fragment, perhaps others). It'd be nice to keep the bidirectional functionality that VEINS offers, although I'm mostly interested in getting traffic data from SUMO into my simulation.
One obvious way to implement this would be to use a warm-up period. However, I'm wondering if there is a more efficient way -- simulating 8 hours of traffic just to get a several-minute fragment feels inefficient and may be problematic for simulations with sufficient repetitions.
Does VEINS have a built-in mechanism for warm-up periods, primarily one that avoids sending messages (which is by far the most time consuming part in the simulation), or does it have a way to wait for SUMO to advance, e.g., to a specific time stamp (which also avoids creating vehicle objects in OMNeT++ and thus all the initiation code)?
In case it's relevant -- I'm using the latest stable versions of OMNeT++ and SUMO (OMNeT++ 4.6 with SUMO 0.25.0) and my code base is based on VEINS 4a2 (with some changes, notably accepting the TraCI API version 10).
There are two things you can do here for reducing the number of sent messages in Veins:
Use the OMNeT++ Warm-Up Period as described here in the manual. Basically it means to set warmup-period in your .ini file and make sure your code checks this with if (simTime() >= simulation.getWarmupPeriod()). The OMNeT++ signals for result collection are aware of this.
The TraCIScenarioManager offers a variable double firstStepAt #unit("s") which you can use to delay the start of it. Again this can be set in the .ini file.
As the VEINS FAQ states, the TraCIScenarioManagerLaunchd offers two variables to configure the region of interest, based on rectangles or roads (string roiRoads and string roiRects). To reduce the simulated area, you can restrict simulation to a specific rectangle; for example, *.manager.rioRects="1000,1000-3000,3000" simulates a 2x2km area between the two supplied coordinates.
With both solutions (best used in combination) you still have to run SUMO - but Veins barely consums any of the time.