Difference in E+ results

asked 2019-05-22 16:03:38 -0500

Mamak
181 ●1 ●3

updated 2019-05-22 18:00:38 -0500

__AmirRoth__

4436 ●5 ●17 http://bleedinggreenna...

Hi everyone, I have noticed a difference between the results of the “district heating meter” When i run the model in 2 modes.

First, I run the model in open studio,and check the energy plus results in the open studio report tab.

Second,I export an idf file , defining the proper meter and run the simulation using the EP lunch.

The first one is higher (about 4000 kwh more) and I don’t know why...and which one is realistic!!!! Thanks in advance if you help me understand this problem.

answered 2019-05-22 21:43:30 -0500

David Goldwasser

20295 ●94 ●14 http://www.openstudio.net/

Do you have any EnergyPlus measures in your workflow when running through OpenStudio? When you export an IDF file, it exports it from the current OSM, prior to any measures being applied to it. If that isn't the case then the next thing I would look at is if the EP Launch run is using a different weather file. While an OSM file has link to EPW file, in EP Launch you have specify that similar to how you specify the IDF file.

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Dear David, Thank you so much for your answer. Yes I have used many Energy plus measures and I thought they would be exported to the idf file. Thanks for the clarification.

Mamak ( 2019-05-23 04:57:31 -0500 )edit

If you want to get the IDF file out of OpenStudio with those measure applied, you can look in the run directory after the simulation has run, so while not as clean as export IDF, it does work. Ideally in future there could be to export IDF options. One with and one without the measures.

If you are comfortable with a command line you can use the OpenStudio CLI with the --measures_only flag to run through the OpenStudio and EnergyPlus measure, but stop there without the simulation.