[Bldg-sim] Explanation of California Energy Commission's new CZ2010 weather files

[Joe Huang]

I am reposting a recent reply I made on the eQuest_Users bulletin board 
explaining the status of California Energy Commission's new weather 
files for Title-24 compliance, because I thought it might be of interest 
to other modelers who might be doing work in California.

Joe

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
http://www.whiteboxtechnologies.com
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"


----------------------------------------------------
Michael,

Your first statement is not quite correct.  The California Energy 
Commission had commissioned in 2009 the creation of a new set of 
standard weather files to replace the pre-existing 16 CZXXRV2 weather 
files, for which I was the contractor.  This work, which was finished in 
December 2011, resulted in a set of 86 CZ2010 weather files and are 
available for public download on my company Web site at 
http://weather.whiteboxtechnologies.com, click on CZ2010  (all files 
contain the same weather file in three formats -  archival *.TM2,  
*.EPW, and *.BINM).

The California Energy Commission has yet to decide whether to allow the 
use of all 86 weather files in Title-24 calculations, or to limit it to 
a subset of 16, i.e., one standard file per Climate Zone as before.  
 From a technical point of view, I strongly support the former position, 
although there are administrative issues that need to be addressed to 
avoid creating confusion or "gaming the system" that I hope the 
Commission will address in the coming year.

As an interim place-holder, I worked with the Commission staff and 
consultants in late 2011 to assign representative locations out of the 
86 for each of the 16  Title-24 Climate Zones.  This list was shown at a 
Nov. 2011 workshop in Sacramento (see attached, full PPT available on 
the Commission Web site - search for "Huang Weather Data Presentation") 
and is probably the basis for what you've heard about the CZ08 file 
changing from El Toro to Fullerton.

Although I am not violently opposed to such an interpretation, I do wish 
to mention the following caveats:
1) the pre-existing CZXXRV2 weather files were adjusted in the early 
1990's (that's the reason for the RV2 designation) to be more 
representative of the climates within each Climate Zone; therefore, it's 
incorrect to refer to any of them as being from a specific location, 
i.e., CZ08RV2 != El Toro.
2) the new CZ2010 weather files have not undergone any such adjustment 
process (nor would I recommend so doing), and should be regarded as 
"representative" rather than "average" weather files for each Climate 
Zone, selected based primarily on population and only secondarily on 
climate considerations.

The last point I want to make is that the CZ2010 files are different 
from the TMY3 weather files for the same stations in many ways:
1) uniform period of record (1996-2009)
2) uniform typical months for all 86 stations
3) solar radiation from remotely-sensed data, i.e., satellite-derived
4) different software used to fill missing data

So, to make a long story short, if you're concerned about the 
Commission's change in standard weather data,  please download the new 
CZ2010 weather files at http://weather.whiteboxtechnologies.com/CZ2010

Joe

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
http://www.whiteboxtechnologies.com
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"


On 7/15/2013 2:01 PM, Busman, Michael R wrote:

It is my understanding that beginning Jan. 2014, California Climate Zone 
8 will change from El Toro MCAS to Fullerton Municipal Airport.

  (portions deleted)

Thank you.

Mike Busman

*Michael R. Busman, CEM*

Lead Project Engineer II

*Chevron Energy Solutions*

A Division of Chevron U.S.A., Inc.

145 S. State College Blvd.

Brea, CA  92821

Direct  714-671-3561

Fax     714-671-3438

eFax   866-420-0335 (Include my Full Name followed by "CAI:MHTZ" on 
Cover Sheet)

Mobile 310-387-2083


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