Do long names affect simulation run time?

asked 2022-10-28 04:31:24 -0500

Keigo's avatar

updated 2022-10-28 04:49:29 -0500

I am having trouble with long running times. I saw some posts (What is the best hardware setup to minimize run time?, EnergyPlus Simulation Run Time Diagnostics) and Tips, but still have the trouble.

Indeed, my model is large. It has approximately:

  • 1000 zones in total
  • 600 conditioned zones
  • 14000 surfaces
  • 100 AirLoops
  • 15 PlantLoops with HeatExchanger:FluidToFluid (Primary, Secondary, Tertiary and Quaternary Loops)

But, I think the run time is too long even taking them into account. The sizing run with 3 design days took 3 hours, and I have not completed the annual simulation yet. As long as I keep an eye on the progress, I guess it will take more than one week.

CPU of my PC is Intel Xeon (3.7Ghz). HVAC systm is not complecated except for the plant loops. VAV, CAV, DOAS, FCU and VRF are modelled using HVACTemplate. The model includes SwimmingPool:Indoor, but I don't think that's the cause of long run time. Only a few simple shadings. No AirflowNetwork. It has many ZoneCross:Mixing objects, but I tried a test case wihtout them and the run time looked the same.

I'm just wondering if the length of names affect the simulation run time. My model has many long Zone Names e.g., 5F_Restaurant_PAU-P-S2M-102_FCU-10x10. I included the designation and number of HVAC equipment in zone names as a reminder because the HVAC drawings are so messy.

Some Eqipment Names are also long e.g., AHU-P-S5-201_301to303_306_307_309_310_402to408_501to503_702. I tried my best to combine AHUs serving the same large zone.

Some equipment names have "/", but no warnings and severe errors about it. I think it is allowed and irrelevant to the simulation time.

For CFD simulation, the long names affect the simulation run time because it stores the names and use use much memory, but I'm not sure if it's the same in energy simulation.

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Comments

It most likely is the number of multizone airloops. I have noticed that the same model with a VAV takes significantly longer to run than a model with, let's say, fan coil units.

Luis Lara's avatar Luis Lara  ( 2022-10-28 09:40:24 -0500 )edit