Jamie Bull's profile - activity

I've come across a strange error where two out of three nearly identical IDFs fail with an output like the one shown below. The only differences are in the size of water heater tank, the size of zones (it's a simple two-zone model), and the thermal properties of the walls (density and conductivity).

What sort of errors in a model produce divide by zero Fortran errors like this one, and how do I go about debugging my IDF?

Warming up {1}
forrtl: error (73): floating divide by zero

Image              PC                Routine            Line        Source             
EnergyPlus.exe     000000014077515B  waterthermaltanks        6654  PlantWaterThermalTank.f90
EnergyPlus.exe     0000000140773E30  waterthermaltanks        6398  PlantWaterThermalTank.f90
EnergyPlus.exe     000000014076D3E7  waterthermaltanks        8085  PlantWaterThermalTank.f90
EnergyPlus.exe     0000000140732069  waterthermaltanks         896  PlantWaterThermalTank.f90
EnergyPlus.exe     0000000140DEA4F4  plantloopequip_mp         673  PlantLoopEquipment.f90
EnergyPlus.exe     0000000140FCBA86  plantloopsolver_m        1270  PlantLoopSolver.f90
EnergyPlus.exe     0000000140FC4826  plantloopsolver_m         270  PlantLoopSolver.f90
EnergyPlus.exe     00000001410857D7  plantmanager_mp_m         184  PlantManager.f90
EnergyPlus.exe     00000001410B71BE  hvacmanager_mp_si        1792  HVACManager.f90
EnergyPlus.exe     00000001410AEF35  hvacmanager_mp_si         694  HVACManager.f90
EnergyPlus.exe     00000001410A2E49  hvacmanager_mp_ma         249  HVACManager.f90
EnergyPlus.exe     00000001410C1CD2  heatbalanceairman         123  HeatBalanceAirManager.f90
EnergyPlus.exe     000000014110FF52  heatbalancesurfac         149  HeatBalanceSurfaceManager.f90
EnergyPlus.exe     0000000141145CC0  heatbalancemanage         215  HeatBalanceManager.f90
EnergyPlus.exe     00000001411C4ED9  simulationmanager         376  SimulationManager.f90
EnergyPlus.exe     00000001411F0359  MAIN__                    421  EnergyPlus.f90
EnergyPlus.exe     00000001413BBA1C  Unknown               Unknown  Unknown
EnergyPlus.exe     000000014139941F  Unknown               Unknown  Unknown
kernel32.dll       00000000778959ED  Unknown               Unknown  Unknown
ntdll.dll          0000000077ACC541  Unknown               Unknown  Unknown

Obtaining data for CRREM in the USA/Canada I'm looking at using the EU-developed Carbon Risk Real Estate Monitor (CRREM)

Obtaining data for CRREM in the USA/Canada I'm looking at using the EU-developed Carbon Risk Real Estate Monitor (CRREM)

The documentation for the ProgramControl object states that some portions of EnergyPlus are able to use more than one processor. So firstly, which portions of the code are able to take advantage of this?

And secondly, what types of models are likely to run faster when the Number of Threads Allowed field is set to 0 to use all threads rather set to run on a single thread? Do models with more or less complex geometry benefit? More or less complex HVAC systems? Specific objects or combinations of objects?

I would like to model a gas absorption heat pump and have run into a problem. My first approach was to model it as a regular air-to-water heat pump WaterHeater:HeatPump object, and set the fuel to NaturalGas. I didn't get very far with this since EnergyPlus throws an error if the COP is too low. The absorption heat pump I'm modelling will have a COP of between 1.15 and 1.25 which is low enough to fail.

So my second approach was to search for gas absorption in the documentation, which turned up ChillerHeater:Absorption:DirectFired - link. This looks like it may be a possibility, but it's set up as a chiller which also provides hot water while I just want the hot water. This means I'll have to set up a condenser loop and a cooling loop, neither of which will actually be used which seems like a waste of time.

My question is is the ChillerHeater:Absorption:DirectFired a valid way of modelling a gas absorption heat pump if I can set it so that the chiller is never activated? Am I missing a better way of doing this?

Edit I've set this up and it's running, and with the chiller and condenser loops having operation schemes that are set to always of I think it's OK. A lot of extra lines in the IDF but it's working.

I'm still interested to know if this is the correct way to model this system or if I've missed a simpler alternative.

I'm finding a strange mismatch between zone area and zone volume in some models I'm building. In the affected models this is having the knock-on effect that a huge amount of heating energy is used, since the infiltration rate is specified as air changes per hour. The tables below show the issue I'm seeing. The first shows the very large volume but with the expected ([edit] or at least reasonable looking) floor and wall areas.

The second shows a more normal volume (for a bigger building) and again expected/reasonable wall and floor areas. This second model was been produced using the same Python script, but with different footprint as input.

An example IDF with the problem is here in case that helps.

The strange thing is that of approximately 45 buildings, roughly half show this problem while the other half appear normal. What could be causing this effect?

Answering my own question to get this going. After a lot of searching, I found a procedure from a BRE report from 2016 t

Estimating plant size from annual energy consumption This is more of an avoiding simulation question rather than how to

Is there a script available from the command line which can take an IDF created by EPMacro (or by hand, Python, etc.) and sort it into the "normal" order as produced by the IDF Editor when choosing the "sorted" order when saving the file?

@dhollman I've edited in a current link

Yes, it is possible. See https://bigladdersoftware.com/epx/docs/9-2/ems-application-guide/general.html#weather-data If y

As @mdahlhausen mentioned eppy, I thought I should add an answer here about geomeppy. While there's no GUI, geomeppy is

An ordinary hot water radiator is a ZoneHVAC:Baseboard:RadiantConvective:Water. A ZoneHVAC:HighTemperatureRadiant heate

@Gio it's a calculated field, made available via a helper function which is added to surfaces when reading in the IDF.

Why is this IDF geometry generated from Sketchup plugin? A GeomEppy user has tried to visualise an IDF created using the

Why is this IDF geometry generated from Sketchup plugin? A geomeppy user has tried to visualise an IDF created using the

I'm updating eppy to be able to use EnergyPlus v8.9.0 (I know, I know, v9.0.0 is just coming out, we'll get there), and one test is failing unexpectedly. This test asserts that if EnergyPlus is called with an IDD version that doesn't match the IDF version, the run fails.

I've tested this outside of eppy and it seems to be an issue with EnergyPlus itself. Is this expected behaviour?

Call:

C:\EnergyPlusV8-9-0>energyplus.exe --idd "C:\Users\<snip>\eppy\resources\iddfiles\Energy+V7_2_0.idd" "C:\Users\<snip>\eppy\resources\idffiles\V8_9\smallfile.idf"

Std out:

EnergyPlus Starting
EnergyPlus, Version 8.9.0-40101eaafd, YMD=2018.10.02 11:35
Adjusting Air System Sizing
Adjusting Standard 62.1 Ventilation Sizing
Initializing Simulation
Reporting Surfaces
Beginning Primary Simulation
Initializing New Environment Parameters
Warming up {1}
Starting Simulation at 12/21 for DENVER_STAPLETON ANN HTG 99.6% CONDNS DB
Initializing New Environment Parameters
Warming up {1}
Starting Simulation at 07/21 for DENVER_STAPLETON ANN CLG .4% CONDNS DB=>MWB
Writing tabular output file results using HTML format.
EnergyPlus Completed Successfully.

eplusout.err

Program Version,EnergyPlus, Version 8.9.0-40101eaafd, YMD=2018.10.02 11:35,
       ************* Testing Individual Branch Integrity
       ************* All Branches passed integrity testing
       ************* Testing Individual Supply Air Path Integrity
       ************* All Supply Air Paths passed integrity testing
       ************* Testing Individual Return Air Path Integrity
       ************* All Return Air Paths passed integrity testing
       ************* No node connection errors were found.
       ************* Beginning Simulation
       ************* Simulation Error Summary *************
       ************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.
       ************* EnergyPlus Sizing Error Summary. During Sizing: 0 Warning; 0 Severe Errors.
       ************* EnergyPlus Completed Successfully-- 0 Warning; 0 Severe Errors; Elapsed Time=00hr 00min  0.30sec`

Why does running EnergyPlus with an old IDD no longer fail? I'm updating eppy to be able to use EnergyPlus v8.9.0 (I kno

I'm working with the Prometheus future weather files and would like to present some summary statistics such as heating degree days, cooling degree days, average wind speeds, climate type, etc. as you can find in the .stat files that accompany a lot of EPWs.

The problem is that the Prometheus files don't have .stat files with them. Is there a tool available to generate them? Or another tool to generate key climate statistics from the EPW file?

Just to add, Geomeppy extends Eppy for working with geometry, and has functions for setting WWR

I'm reading through the EMS documentation and I see that I need to include some EMS objects before the .edd file (which tells me what EMS objects are available) is produced. Is this as chicken-and-egg as it sounds or have I missed some higher level EMS object I can add?

I've added this part at the end of the file, but what other object should I add as a starter that will allow the .edd to be produced?

Output:EnergyManagementSystem,
    Verbose,    ! Actuator Availability Dictionary Reporting
    Verbose,    ! Internal Variable Availability Dictionary Reporting
    ErrorsOnly; ! EnergyPlus Runtime Language Debug Output Level

In a space with a roof, how does OpenStudio know whether it should apply a pitched roof or a flat roof construction?

I have a question from a guy in my alumni group, asking what simulation software is available that can handle airflow in stacks, such as concrete/steel/GRP towers?

Does anyone have any specific experience with the CFD module in IES:VE for example, or have any other suggestions/recommendations?

This is based on another user's question. It has has since been deleted but I think it's worth asking anyway.

Air velocity is a required input for thermal comfort calculations but I'm not clear on how it is entered in EnergyPlus. What type of objects need to be included?

Also, what would typical values be in a domestic situation? I'm looking for references, typical values based on engineering experience (rules of thumb), or ways of measuring/estimating air velocity in existing buildings.

The problem is you're missing the "geos_c.dll". I don't know how you're installing shapely, but this error can occur if

How to install geomeppy for windows? Hi! I have been trying to install Geomeppy (0.4.8) for Windows. As I understand, th

Digging in the crates here... This can be done by adding extensions to ASKBOT_ALLOWED_UPLOAD_FILE_TYPES in the django se

Normally I use esoreader to parse the output while staying in the python ecosystem

You need to set an environment variable DYMOLA_RUNTIME_LICENSE to the location of your license file. How to do this depe

You need to set an environment variable DYMOLA_RUNTIME_LICENSE to the location of your license file. How to do this depe