Time consuming simulation


#1

Hi
I am trying to simulate a curved building with the least activity within the components and it takes way much of time just for one simple day. I changed my PC to a one with much stronger CPU and RAM , but it also didn’t change a lot. My first PC was working with 50% of its RAM and 25% of CPU, and the second works with the same percentages, which means the second should work with much capacity of RAM and a faster CPU.The most time consuming part is the solar reflections in both computers. How could it be possible to save the time?
Thanks


#2

Hi @EhsanFouladi

You can decrease the solar distribution factor to a less accurate condition … the default is 4 which is the most accurate one as recommended…


#3

Thanks Amir,
By the way, the question is why the solution time for both computers doesn’t differ considerably.


#4

What kind of simulation are you running? If this is energy simulation then energy plus runs on a single thread so a faster CPU will help a bit but adding more cores will not change anything. If you are running radiance then there are a few options to speed up the process:

  1. Split the simulation into smaller simulations and run them in parallel
  2. Download accelerad and get a good GPU

#5

Hi @EhsanFouladi You should tell me which type of performance analysis. Time consuming is very different based different type. In my experience, time consuming from short to long is: grid-based sunlight hour <grid-based solar radiation <grid-based daylighting<image-based daylighting< thermal load < HVAC annual energy usage.


#6

Thanks for your replies.
I want to simulate annual energy consumption of my conceptual model. I made it just with one simple zone and no HVAC system is included. So you mean increasing RAM capacity doesn’t affect the simulation time?


#7

Thanks @minggangyin
The simulation is annual energy consumption run by EnergyPlus.


#8

My understanding is that RAM won’t change much. RAM is used to retrieve data quicker but not to process it quicker. The bottleneck with energyplus is processing. If you want to dive deep into how to optimise for EnergyPlus I would recommend checking this thread out.

It would be good to understand what you feel is too much time for a simulation. eg: 5 min simulation is not a problem if you just want to run 1 simulation. 5 mins is a problem if you want to run 5000. If you want to run many then I’d recommend looking into running simulations in parallel by using cloud services or a PC with 8+ cores in the CPU.

Good luck!


#9

I have faced the same issue before, RAM doesnt change much but converting your hard drive to a SSD hard disk definitely changes the simulation time … However, I imagine writing the least complex algorithm increase the simulation speed as well…