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Re: [EnergyPlus_Support] Processing multiple years in epw





I'm not a proponant of using short term weather statistics for design decisions. Weather simply varies too much from "year to year" or "5 years to 5 years" if you will. This is what good designday files and sensitivity analysis is for...

...but try explaining that to the owner/client/wife...as soon as it snows in September, it must be due to global warming...they just don't want to believe that the effects of global warming is only to be seen by looking at periods of hundreds of years.

Frankly, I'm starting to doubt myself simply because everyone else does. :-(

On 07.11.2014, at 15:43, "'Edward G. Lyon' eglyon@xxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

It is very helpful for model calibration when you use actual site weather data.  I am currently evaluating a building that has one season baseline with old windows and two seasons new windows.  I am running winter heating season only because there is no mechanical AC for most of the building, so currently I have split years and squeeze them into a one year file.  It will be much easier to have a multi-year block of weather and then just select an appropriate run periods.  It will also be easier to compare different weather sources.  Finally, if I had a natural ventilation model, I would like to show my clients how well it works over something like the last 3 to 5 years of actual weather, not just the artificial year.  

 

Ned Lyon, P.E. (MA, WV)
Staff Consultant

SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct 
617.285.2162 mobile 
781.907.9009 fax
www.sgh.com

 

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Friday, November 07, 2014 6:29 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Processing multiple years in epw

 

 

Hi, thank you for the post. the idea of simulating for more than a year (8760 hours) for the given energy system is really interesting. Just wondering, whether, we as a building owner/ regulator/ simulator, requires that data/ information. Typically, a year covers most weather patterns and climate changes. This leads to another prediction how to include next year weather data in .epw file given the vast uncertainties due to possible "seasonal changes" and so on... Is there any such provision in EP to include second year simulation period? 

 

Regards,

Arun Bhandari

eCUBE solution

Bangalore, India

Sent from my iPhone


On 07-Nov-2014, at 10:22 AM, "'jeannieboef@xxxxxxxxx' jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

I recently accidently entered a start date "older" than the end date. E+ started with the start date, ran to the end of the year, continued flawlessly from January untill it stopped at the end date. It used a regular weatherfile.

 

And after my innial confussion, there came an exclamation :-)

Mit freundlichen GrüÃ?en- Sent from my iPhone (excuse the brevity)

 

i. A.

Jean Marais

b.i.g. bechtold

Tel.   +49 30 6706662-23


On 06.11.2014, at 19:07, "Linda Lawrie linda@xxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

I cannot parse what you are saying, Ned.  I read it over twice.

There are two ways that EnergyPlus can run multiple years -- with the RunPeriod object and the repeat field.
Also we implemented something about actual year -- I can't remember if that applies to the RunPeriod, the CustomRange or both.

The CustomRange expects weather files that are hand crafted to have actual dates in the date fields and in the header (so it knows if the selection is on the weather file or not).  And they are merged together in one large file.

I can likewise send you the files I just sent Jim that implement same.

Linda

At 09:02 AM 11/6/2014, 'Edward G. Lyon' eglyon@xxxxxxx [EnergyPlus_Support] wrote:

I think what is not very clear in the documentation is if the custom weather file is the .csv file format (created from the weather generator opening a .epw or generating form some other source) or the .epw format with more than a year of data actual date order.  I suspect the latter?
 
Ned Lyon, P.E. (MA, WV)
Staff Consultant
SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct 
617.285.2162 mobile 
781.907.9009 fax
www.sgh.com
 
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [ mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Thursday, November 06, 2014 10:49 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Processing multiple years in epw
 
 

Jim is right, of course - as usual.

I can send you both a file that does a custom range and a weather file.

You will need to hand create the weather file (appending the 2nd year onto the first or similar).

 I would send it to you privately. 

At 04:44 AM 11/6/2014, Jim Dirkes jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support] wrote:

Marko,

The purpose of the CustomRange object is for >365 day weather years, as I understand it.Ã?  I think this object became available about 2 years ago.Ã?  I was one of those who requested it so that it would be more practical to model existing buildings where the electricity and gas billing periods extended for longer than one calendar year. As it happens, I have not tested it yet, but expect to do so soon.

Ã?

On Thu, Nov 6, 2014 at 5:38 AM, marko.ignjatovic1980@xxxxxxxxx [EnergyPlus_Support] < EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

Ã? 
Hi all,

I have problem running simulation for two consecutive years, ie. processing raw weather data in epw. I have raw weather data starting from October 15th 2013 until October 31st 2014. Can I create extended epw containing this data period (creating epw for 8760 values is no problem)? I read I/O documentation and found that RunPeriod:CustomRange can do the trick but I am not sure. Any comment is more than welcome

MarkoÃ?



--

Ã?

James V Dirkes II, PE, BEMP, LEED AP
The Building Performance Team
1631 Acacia Drive, Grand Rapids, MI 49504
(M) 616 450 8653

The more one does what is good, the freer one becomes. There is no true freedom except in the service of what is good and just.



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Posted by: "jeannieboef@xxxxxxxxx" <jeannieboef@xxxxxxxxx>


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