Stack effect airflow #1246

kldjonge · 2022-01-10T10:32:03Z

Development of the two-port infiltration/interzonal airflow implementation introducing density-columns.

Got rid of the unnecessary initial equations

kldjonge · 2022-01-10T14:55:52Z

The error occurs in this model when used in a full building model: IDEAS.Buildings.Components.Interfaces.PartialSurface.PowerLaw_q50_stack.

The error:
Current version of the Modelica translator can only handle
conditional components with fixed condition.
But component struct.W1.res1.col_a_pos had non-fixed condition if ColApos

But I don't know which of the conditions it assumes as non-fixed. All conditions are fixed parameters.

The point of this model to either have:

No density column
A positive column (port_a connecting to the bottom port)
or a negative column (port_a connecting to the top port)

Mathadon · 2022-01-17T09:55:17Z

IDEAS/Buildings/Components/Interfaces/PartialSurface.mo

+
+      /*ERROR:  Current version of the Modelica translator can only handle
+*/
+      final parameter Boolean ColApos=StackEff and h_a>0;


@kldjonge can you try to add annotation(Evaluate=true) to the definition of these variables to try to fix your issue?

I tried but it doesn't seem to solve the error.

New implementation for the density columns to avoid error due to conditional statements in the column heights

Changed error in input of door component.

kldjonge · 2022-01-19T11:23:34Z

I changed the implementation entirely to avoid the conditional statements altogether. First results for the holzkirchen case show a slight underestimation of temperatures but it seems like the dynamics match better.

… and flow element(s) Assign height difference between meteorological pressure measurements and flow element(s). Also, by default corrects for the windspeed using this height when the TwoPort implementation is used.

cosmetic change

kldjonge · 2022-01-19T16:06:37Z

@Mathadon, everything seems to work except for the models using the IDEAS.Buildings.Components.Examples.BaseClasses.SimpleZone (Rectangular zone). They error because of a singularity without further clarification. As most examples use this implementation, I guess it is used often (?)

E.g. in IDEAS.Buildings.Components.Examples.LightingControl when I change the settings to twoPort in the sim.

option added to get better default for roofs. This needs to be fine-tuned based on available data.

Table introduced from Energy efficient guide to ventilation, Appendix 2 Table 2.1

… examples Examples not connected to case 900 for the rectangular zone template including "simulate and plot" scripts. Error for TwoPort still needs to be fixed.

kldjonge · 2022-01-24T17:53:35Z

At this point, a review of the implementation would be nice. If no major changes are necessary I will start to work on the CONTAM model for reference results.

…as#1232

added trickle vent model for open-ideas#1232

bugfix for open-ideas#1251

Mathadon · 2022-08-26T13:25:16Z

This is a new parameter and it should probably have a default indeed!

Todo FJ:

Add epsSW_shading default

When an opening is horizontal, no different flows are expected due to the lack of stack effect, thus simplifying to less compartments is logical. Can this be 1?

kldjonge · 2022-08-26T14:51:58Z

This is a new parameter and it should probably have a default indeed!

Todo FJ:

Add epsSW_shading default

Great that you would have a look at it so I can test it. In the meantime I updated the CONTAM model (and did some minor changes to the default modelica implementation along the way).

In the CONTAM model, the stack-effect airflow trough the staircase openings is +- 50m³/h. So it will be a good case to verify the model implementation with.

…g/Interfaces/PartialShading.mo

Mathadon · 2022-08-27T14:04:34Z

done in a681abf !

Mathadon · 2022-08-27T14:05:39Z

50 m3/h is substantial but not that big, for what ∆T is that?

commit 121cb9c Merge: 06aa135 a681abf Author: kldjonge <46526840+kldjonge@users.noreply.github.com> Date: Mon Aug 29 09:00:13 2022 +0200 Merge branch 'open-ideas:master' into master commit a681abf Author: Filip Jorissen <filip.jorissen@gmail.com> Date: Sat Aug 27 16:04:04 2022 +0200 default value for epsSw_shading in IDEAS//Buildings/Components/Shading/Interfaces/PartialShading.mo

kldjonge · 2022-08-29T15:12:49Z

Annoying news, the 2-port implementation has become singular. I've been trying to pin-point the problem but can't seem to find it as the error-message isn't particularly helpful.

The CONTAM simulation is with a fixed indoor temperature of 20°C in all spaces.

Mathadon · 2022-08-30T20:07:58Z

Yikes.. I tried using OpenModelica but I'm not getting a clear error message there either.

kldjonge · 2022-08-31T07:57:47Z

When I put the Holzkirchen model to two ports, it only fails at initialization. Maybe you know what to do with this?

Warning: Failed to solve nonlinear system using Newton solver.
  During initialization at time: 15000000
  Tag: initialization.nonlinear[8]
  For debugging information enable
  Simulation/Setup/Debug/Nonlinear solver diagnostics/Detailed logging of failed nonlinear solutions.
Trying to solve non-linear system using global homotopy-method.

Warning: Failed to solve nonlinear system using Newton solver.
  During initialization at time: 15000000
  Tag: initialization.nonlinear[8]
Error: Integrator failed to start model.

ERROR: The simulation of IDEAS.Examples.TwinHouses.BuildingO5_Exp1_1Port FAILED

And warnings in the translation log:

So it seems that the singularity error might only be related to the rectangular zone model.

kldjonge · 2022-08-31T08:22:07Z

How can I couple my forked branch to this PR again? New commits don't show up here anymore because you merged it into open-ideas:StackEffectAirflow (for which I don't have write acces).

Simple models with two-port airflow do seem to work just fine.

Mathadon · 2022-08-31T08:36:09Z

You can just make a new PR, I think?

kldjonge · 2022-08-31T08:48:25Z

Getting closer! IDEAS.Examples.Example5 works with the two-port implementation on but fails after a while when also a cavity is added in the internal wall.

Mathadon · 2022-08-31T11:45:15Z

Alright! What error message is thrown?

kldjonge · 2022-08-31T12:14:32Z

Warning: Failed to solve nonlinear system using Newton solver.
  Time: 10160091.04919381
  Tag: simulation.nonlinear[1]
  For debugging information enable
  Simulation/Setup/Debug/Nonlinear solver diagnostics/Detailed logging of failed nonlinear solutions.

Integration terminated before reaching "StopTime" at T = 1.02e+07

But, so it turns out, it also happens when in the 1 port version, a cavity is added.

In general I am thinking that maybe the number of available ports is the issue? Particularly the fact that when the infiltration models need 2 ports and the door model needs another 2, double connections are made at the moment (Same thing for the trickle vent model). I'm not sure what happens in these fluid-connectors when each time, a density column is used.

Mathadon · 2022-08-31T17:30:05Z

The problem is that an algebraic loops is not converging. This probably either means that the system is ill-conditioned or it has no solution. I'm guessing it's the former because the cavity causes relatively large mass flow rates for small pressure drops, which can cause ill-conditioning.

Can you try setting in IDEAS.Airflow.Multizone.BaseClasses.DoorDiscretized

  parameter Modelica.Units.SI.PressureDifference dp_turbulent(
    min=0,
    displayUnit="Pa") = 0.1;

(instead of 0.01) and see whether that helps?

kldjonge · 2022-09-01T09:37:15Z

No that doesn't solve it.

On the hunch that it might cause errors to make double use of the fluid-ports I tried to make the amount of fluid ports in the zone connector variable with the goal to then 'count' the amount of ports in the zone. I didn't manage for now because it wants to know the amount of connection beforehand. (https://github.com/kldjonge/IDEAS/tree/More-ports)

Update PartialSurface.mo

96a4087

Got rid of the unnecessary initial equations

Mathadon reviewed Jan 17, 2022

View reviewed changes

kldjonge added 4 commits January 18, 2022 08:54

Update PartialSurface.mo

d0f7ab6

Updated airflow part of PartialSurface

7795acd

New implementation for the density columns to avoid error due to conditional statements in the column heights

Update InternalWall.mo

c86cad2

Changed error in input of door component.

Changed documentation of PowerLaw_q50_stack

1444989

kldjonge added 4 commits January 19, 2022 15:59

Update PartialSurface.mo

a9e4c01

cosmetic change

Internal references for Cs

cb815c6

Update Window.mo

7797995

kldjonge added 5 commits January 19, 2022 17:12

Check Ceiling vs Floor succesfull

40ed854

Added replaceable records for wind pressur coefficient

82c4b3d

option added to get better default for roofs. This needs to be fine-tuned based on available data.

Fine-tuned default voor Cp_table

164357a

Table introduced from Energy efficient guide to ventilation, Appendix 2 Table 2.1

Update Lowrise_Square_Exposed.mo

82cfd9f

Simple zone template examples with 3 different airflow implementation…

894876e

… examples Examples not connected to case 900 for the rectangular zone template including "simulate and plot" scripts. Error for TwoPort still needs to be fixed.

kldjonge mentioned this pull request Jan 24, 2022

RectangularZone combined with InterZonalAirFlow.TwoPorts #1247

Closed

kldjonge marked this pull request as ready for review January 24, 2022 17:50

kldjonge and others added 9 commits February 18, 2022 17:01

Merge branch 'open-ideas:master' into master

a316235

added HSha in PartialShading

7bfa46d

trickle vent refactor for open-ideas#1232

c5c978a

Merge branch 'master' into 1232_tricklevent

6af90e9

displayunit = pa in IDEAS/Buildings/Components/Window.mo for open-ide…

4605d06

…as#1232

Merge pull request open-ideas#1234 from open-ideas/1232_tricklevent

5986ad9

added trickle vent model for open-ideas#1232

bugfix for open-ideas#1251

349c413

heat flow rate sensor added

3d4c78b

Merge pull request open-ideas#1252 from open-ideas/1251_latGai

491cbdf

bugfix for open-ideas#1251

final Habs_surf

728119e

kldjonge added 2 commits August 26, 2022 15:32

Simplify horizontal openings

466e8de

When an opening is horizontal, no different flows are expected due to the lack of stack effect, thus simplifying to less compartments is logical. Can this be 1?

Assigned column heights for sloped roof

e25590c

default value for epsSw_shading in IDEAS//Buildings/Components/Shadin…

a681abf

…g/Interfaces/PartialShading.mo

kldjonge and others added 11 commits August 29, 2022 09:00

Merge branch 'open-ideas:master' into master

121cb9c

Uprotected A0, a and Hwin and moved it to Overwrite tab

b274c74

Fixed internal references

95e84bf

Update OutsideAir.mo

c39e5cc

Update Structure.mo

a8f089b

Merge branch 'master' into StackEffectAirflow

39e8984

Merge branch 'master' into BeforeMergefault_210042022

55bf8c6

Merge fixes

2d5604a

Merge branch 'BeforeMergefault_210042022' into StackEffectAirflow

f61f67f

Update Window.mo

1a8139b

Mathadon merged commit 678ef99 into open-ideas:StackEffectAirflow Aug 30, 2022

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Stack effect airflow #1246

Stack effect airflow #1246

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Stack effect airflow #1246

Stack effect airflow #1246

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