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Re: [EnergyPlus_Support] Re: Why does this output file show no cooling electricity use ?





Jeremiah,

I 've checked.  There were no differences in the output variables and formats between the 7.0 and 7.1 IDFs (see attached).   In fact, if you ignore the comments, there are literally just a handful of differences, all in the design day inputs.

Multi-threading helps if you're just doing one run at a time, because you're utilizing other processors that might otherwise be idle.  However,  when you have a large set of runs, you don't get any advantage, because what's typically done is to run processes on each core at the same time. For example, a couple of weeks ago I created a "largish" data base of 12,000 DOE-2 runs for the energy saving potentials of awnings and shade screens in 50 US cities. Since I have a 4-core machine, I just gave each core a quarter of the runs to do.  The whole thing took about an hour.

Joe
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga CA 94556
yjhuang@xxxxxxxxxxxxxxxxxxxxxxxx
www.whiteboxtechnologies.com
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

On 6/7/2012 1:46 PM, CleanTech Analytics wrote:
Joe, 
I think I remember changing some output variables and formats, possibly the issue for Energy Plus 7 was the problem?

The latest version of Energy Plus uses OpenMP processing, to use it you choose number of threads dependent on:
  • How many processors are available on the system.
  • If <= 30 nominal surfaces, arbitrarily setting the number of threads to 1.
  • For more surfaces add more threads, 
The feature when used correctly saves computational time- for large files with many surfaces by using more threads. The issue is that for a large file with lots of surfaces using one thread takes more time, or if you are doing parallel processing you have to be careful not to stack to many parallel  runs on top of threads or the excessive computer memory space slows down the run. 

Glad your up and running with your file and best regards-



There should also be a non-threded version in your a folder. I use the non-threded version for jE+ becuse it uses parallel processing, also when runing multaple files from EP Launch it may be better to run the non-threded version. 



Jeremiah D. Crossett
CleanTech Analytics
503-688-8951

This document may contain valuable information proprietary to CleanTech Analytics which is private and confidential. It may not be shared, copied, stored or transmitted in any form without the prior written consent of CleanTech Analytics




On Thu, Jun 7, 2012 at 1:27 PM, Joe Huang <yjhuang@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
First, I'd like to thank Jeremiah, Justin, and Dru for bothering to look into this problem, and those others who've given me their best wishes.

Although the inquisitive side of me wanted to know what I was doing wrong, I finally took up Jeremiah's suggestion and upgraded to Version 7.1, and the problem went away, i.e., I'm now getting cooling electricity for the exact same file, upgraded from Version 7.0 to Version 7.1.  I've also gone back and ran the original Version 1.4 IDF straight from doe2ep, and there too the Cooling Electricity reported normally.

So, I'm chalking this up to some bug in the reporting routines in Version 7.0.  I am quite surprised that nobody else has reported this major problem earlier; isn't the cooling electricity consumption one of the most important variables in a building energy simulation ?

Attached are the multiple IDFs and *.mtr from Versions 1.4, 7.0, and 7.1, in case anyone wants to do some forensics on this glitch.

As a sidelight, I also recorded the run times between the 3 versions.  EnergyPlus seems to have sped up by a third from V1.4 to V7.0, but then slowed back down in V7.1.  I thought there was an effort to make EnergyPlus run faster the past 3-4 years.
   Version 1.4   132.8 seconds
   Version 7.0     90.3 seconds
   Version 7.1   145.5 seconds
Just as a contrast, DOE-2.2 took 66.0 seconds to do the entire set of 33 runs, or 2.0 seconds per run.


Joe
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga CA 94556
yjhuang@xxxxxxxxxxxxxxxxxxxxxxxx
www.whiteboxtechnologies.com
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

On 5/31/2012 10:33 PM, CleanTech Analytics wrote:
Joe, 
I made some small changes to your file, ran it and found cooling energy use, see attached and below.

Let me know if you have any questions and best regards-

Source Energy End Use Components Summary


Source Electricity [kWh] Source Natural Gas [kWh] Source Other Fuel [kWh] Source District Cooling [kWh] Source District Heating [kWh]
Heating 32441.55 0.00 0.00 0.00 0.00
Cooling 804178.78 0.00 0.00 0.00 0.00
Interior Lighting 2491523.65 0.00 0.00 0.00 0.00
Exterior Lighting 0.00 0.00 0.00 0.00 0.00
Interior Equipment 1214184.16 0.00 0.00 0.00 0.00
Exterior Equipment 0.00 0.00 0.00 0.00 0.00
Fans 361727.88 0.00 0.00 0.00 0.00
Pumps 0.00 0.00 0.00 0.00 0.00
Heat Rejection 0.00 0.00 0.00 0.00 0.00
Humidification 0.00 0.00 0.00 0.00 0.00
Heat Recovery 0.00 0.00 0.00 0.00 0.00
Water Systems 0.00 0.00 0.00 0.00 0.00
Refrigeration 0.00 0.00 0.00 0.00 0.00
Generators 0.00 0.00 0.00 0.00 0.00
           
Total Source Energy End Use Components 4904056.01 0.00 0.00 0.00 0.00


Jeremiah D. Crossett
CleanTech Analytics

This document may contain valuable information proprietary to CleanTech Analytics which is private and confidential. It may not be shared, copied, stored or transmitted in any form without the prior written consent of CleanTech Analytics




On Wed, May 30, 2012 at 10:24 PM, Joe Huang <YJHuang@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
 

I made a mistake in my last posting. I had attached the DOE-2 packed weather file instead
of the EPW weather file. However, the good news
is that file is quite small. This time, I'm attaching the correct EPW weather file along
with the IDF and CSV output files, but zipped to reduce the size of the file.

Joe



Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga CA 94556
yjhuang@xxxxxxxxxxxxxxxxxxxxxxxx
www.whiteboxtechnologies.com
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

On 5/30/2012 10:11 PM, Joe Huang wrote:
> I've created a set of idf files for a set of large retail models originally developed in
> DOE-2.2. The outputs show plenty ofcooling going on (Cooling Rate) , but no cooling
> electricity use. I suspect the problem is a mismatch in the output variables, but I
> can't find the source of the problem. Any help would be appreciated. Attached are the
> IDF, weather file, and monthly CSV output files.
>
> Joe
>




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