Re: [EnergyPlus_Support] Simulation Time

Attached is an example jE+ project of a modified version of the USDOE large office. It models 10 floors, 4 orientations with ASHRAE constructions and varris PCM configurations for each orientation.

It is in version 8 and works fine with the JESS server and uses the surrogate model approach I mentioned before.

If you wanted to use this for your study, you could simply change the people, lights, hot water and electrical equipment to match your model, then delete the surfaces, fenestrations and replace them with those from your model to this file then modify the parametric options within jE+.

You could do zone models for the key areas that have the most impact, then use the results to decide what changes you wish to make on your larger model. The only thing is that because this is ideal loads your HVAC options are limited..

Jeremiah D. Crossett | Senior Analyst | Phase Change Energy Solutions

120 E. Pritchard St. | Asheboro, NC 27203 | Mobile 503-688-8951

www.phasechange.com

On Thu, Jul 25, 2013 at 2:53 PM, Yi Zhang <yizhang@xxxxxxxxx> wrote:

Hey, this is my favourite topic!

Touraj, do you know which i7 processor you have in your laptop? Whichever it is, I bet that I can cut the simulation time by half if you convert your model to v8 and send it to my i7 desktop. You can do that by getting the latest JESS Client from http://www.iesd.dmu.ac.uk/~jeplus/wiki/doku.php?id=jeplusplus:download. I will then send you the address of my desktop with a passcode.

Cheers,

Yi

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of rahul a
Sent: 25 July 2013 21:33

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Simulation Time

You might want to look at the error file for recurring errors. Look for warnings starting with "SimHVAC." If HVAC loops don't converge then it might add to simulation time. Here's what the error looks like:

SimHVAC: Maximum iterations (25) exceeded for all HVAC loops, at SALEM OR USA TMY2-24232 WMO#=726940, 02/05 10:50 - 10:55

This usually means two or more components or setpoint managers are fighting with each other.

Also, if you have a big model, and it looks like you do, then more zones can sometimes result in lower simulation times. This is because if a single zone has a large number of surfaces, it takes longer to solve than more zones with fewer surfaces per zone.

Rahul

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