scottb's profile - activity

I find myself in the need of a diagnostic for visualizing heat transfer through various surfaces either on a design day, monthly or annual basis.

Anybody else on this forum come across a similar need? Any open source solutions?

My solution reads in the following variables and identifies appropriate surfaces (walls, ceilings, windows, doors, etc) from the SQLite database. It's a python script.

       'Surface Outside Face Conduction Heat Loss Rate [W]',
       'Surface Outside Face Net Thermal Radiation Heat Gain Rate [W]',
       'Surface Outside Face Convection Heat Gain Rate [W]',
       'Zone Infiltration Total Heat Loss Energy [J]',
       'Zone Infiltration Total Heat Gain Energy [J]',
       'Surface Window Heat Loss Rate [W]', # Total heat transfer through window

The thing is I get strange results which I am not confident in. This could be due to several reasons such as not characterizing convective, conductive or radiative heat transfer in my outputs. Could be for other reasons.

Would like to compare solutions to others to build more confidence in these types of diagnostics.

call me old fashioned, but what's wrong with?:

from glob import glob
for f in glob('*idf'):
    for w in glob('*epw'):
        # RUN EPLUS

I mean it's not a one-liner like in shell. But, hey, what the heck. Why wait till you're 60 to start acting wise?

Amir- I know you're joking, but seriously learn shell! There is an old saying: "When the only tool you have is a hammer, everything starts to look like a nail". I am a big python fan, but there are often simpler solutions. Why reinvent a perfectly good wheel?

Shell rules! Look at all the text in this solution...

Consider simplifying your python script using glob('*idf') and glob('*epw'). Cleans things up a bit

If I was on a linux/mac machine I would use bash:

From command line:

for f in *idf; do runenergyplus $f WFILE; done

Where WFILE is the path to your weather file

If you want to run on all IDFs and all EPWs

for f in *idf; for w in *epw; do runenergyplus $f $w; done

You can put this into a script if you want.

This will work on windows too but you will have to install cygwin first.

Mods- Can we move this to a separate question?

Check out the option unitsOfExecution defined in OptimizationSettings{}

It defaults to the number of processors on your machine. You can set it to the number of threads

Example:

OptimizationSettings{

MaxIte = 2000;

MaxEqualResults = 100;

WriteStepNumber = false;

UnitsOfExecution = 8;

}

Do you have the same unmet hours in both cases?

Check your HTML output for 'Time Setpoint Not Met During Occupied Heating' and 'Time Setpoint Not Met During Occupied Cooling'

Why not use E+ directly and side-step OpenStudio?

Just make sure the following system variables are setup in bash/zsh

Ex.

export ENERGYPLUS_DIR=~/energyplus/EnergyPlus-8-2-0

export ENERGYPLUS_WEATHER=$ENERGYPLUS_DIR/WeatherData

export PATH=$PATH:$ENERGYPLUS_DIR

You can then just use:

runenergyplus XXX.idf WEATHERFILE

As of E+ v8 and onwards, the bin directory is no longer used. So 'PreProcess' and 'PostProcess' is the standard install.

Great! Glad I brought this up. I was confused by the f90 vs cpp issue as well

Is there any intent to open source the ExpandObjects tool for pre-processing IDFs?

I find myself occasionally wishing I could develop new HVACTemplate objects to suite my needs.

Thanks

Attach the IDF please

Also, specify how you originally created it.

How do others set up Design Day objects (0.4%, 1%, 2% and 99%, 99.6% variants) for purchased weather data sources (WeatherAnalytics, etc)? Should I be nagging WA for more information?

I have been using the dated DOE weather sources (slight tendency to oversize in my climate zone). I know ASHRAE handbooks provide information for some climates. I assume best practice would be to extract this directly from the weather file. If not, how do others do it?

Curious if anyone is willing to share a script to automate this process.

Thanks!