How to reduce simulation time with EnergyPlus compiled from source code?

asked 2017-10-11 02:22:24 -0500

Stefan Koenders
23 ●3

updated 2017-10-16 18:52:43 -0500

__AmirRoth__

4436 ●5 ●17 http://bleedinggreenna...

Hi all,

I have a question about the simulation time of EnergyPlus when using the developers code. The reason I want to use the developers code is that I need to adjust some small things in one of the source codes of a module.

First of all I would like to state that I am completely new to the developers side of EnergyPlus, so perhaps it is just an easy fix. I have downloaded the source code from EnergyPlus GitHub page and have followed all the steps which are described in the tutorial on building EnergyPlus (also on the GitHub page). Using CMake and Visual Studio I can build a functional model of the EnergyPlus source code as downloaded (I have made no adjustments to the source code so far).

When I run a simple simulation which calculates the heating load of a single room over a year, my approximate simulation time with the standard EnergyPlus 8.6.0. version is 30 seconds. So it is a simple, not demanding simulation model. However, when I use my self-compiled developers version of EnergyPlus 8.6.0., my simulation time increases to 550 seconds. Using other simulations which are a bit more complex, results in an increase in computation time from 2.5 minutes to approximately an hour.

I have the suspicion that the standard version of EnergyPlus is optimized for speed, but certain compiler settings make the developer version a lot slower. Am I right about this and do other people experience similar results?

Perhaps some of you have some tips for building a fast self-compiled version of EnergyPlus based on the developers code? For these simple simulations the computation time is not that big of a problem, but my goal is to simulate a whole building, which would now result in very long simulation times.

Thank you in advance!

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answered 2017-10-11 22:05:14 -0500

Jason DeGraw

2208 ●6 ●10 https://github.com/jasondegraw

There could be some differences in the released versions and what you're building, but that speed difference sounds like you're building in Debug mode. Double check that you're building in Release mode first. If you are building in Release mode already, then there might be something wrong with your build, and it would help if you provided details like Visual Studio and Windows versions, CPU etc.

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Thank you very much! Indeed, the problem was that I built from Visual Studio in Debug mode. Now that I have changed it to Release mode, my file works perfectly!