[BLDG-SIM] Day-Lighting and DOE2.1E

[Douglas Mahone]

Varkie - 
 
You raise an old issue (old, in the sense that when I was on the ECB
subcommittee leading up to the adoption of  90.1-1999 we spent a lot of
time talking about this) - how to ensure that th eintent of the standard
is not defeated by the detailed modeling decisions of the analyst.
 
California has a long history of providing detailed technical
specifications for modeling software (or a front end thereto) to ensure
that simulations are done correctly for compliance.  Indeed, one can
only use CEC-certified compliance software for that purpose. The user
inputs and the user interface are specified, modeling assumptions are
built into the software, and outputs are standardized.
 
For 90.1, the committee did not have the resources to develop a
comparably detailed specification.  The effort of the committee was to
clearly state the intention of the standard, and to describe in concise
terms how the proposed and budget designs were to be modeled consistent
with the rest of the standard.  The expectation was that private vendors
would take it from there and generate compliance software that met the
intent of the standard, as well as any locally adopted variations in the
states and jurisdictions that would adopt 90.1.  It was left to the
adopting authorities to certify the software for compliance purposes.
There was even some talk of ASHRAE getting into this business, but no
leadership emerged to capitalize on this opportunity.
 
So that was the intent for how the problems you raise would be
addressed.  I haven't followed the story very closely since then, but it
is my impression that compliance software has not emerged, and that
there is therefore a lot of opportunity for analysts to game the ECB
method. I hope I'm wrong about this.
 
Doug.



Douglas Mahone, Principal
Heschong Mahone Group, Inc.
11626 Fair Oaks Blvd. #302
Fair Oaks, CA  95628

(916) 962-7001 x30
fax (916) 962-0101
dmahone at h-m-g.com

web site: www.h-m-g.com



	-----Original Message-----
	From: Varkie Thomas [mailto:Varkie.Thomas at som.com] 
	Sent: Thursday, January 22, 2004 2:41 PM
	To: BLDG-SIM at GARD.COM
	Subject: [BLDG-SIM] Day-Lighting and DOE2.1E
	
	

	I am forwarding my response to Larry Degelman in case there are
others in the BLDG-SIM Group that might be interested.  Varkie

	 

	-----Original Message-----
	From: Varkie Thomas 
	Sent: Thursday, January 22, 2004 3:03 PM
	To: 'larry at taz.tamu.edu'
	Subject: RE: [BLDG-SIM] Day-Lighting and DOE2.1E

	 

	Larry

	 

	Thanks for your response.  The percent glass of all building
envelopes designed by architects in this office is greater than 50%.
This has to do with exterior appearance, indoor working conditions,
building construction costs, exterior maintenance costs and client
satisfaction.  So we always have to use the energy cost budget method to
show code compliance.  We have been doing this with DOE21.E.  First
analyze the building with Std90 criteria (50% glass with Table B
properties, lighting densities, EERs, COPs, etc.) and then with the
proposed building design using more efficient glass, lights, systems,
equipment and renewable energy sources that will produce less than or
equal to energy use and cost (using thermal storage, etc.) results.  The
attachment to our energy report includes the DOE2 output BDL for the
base and the proposed designs as verification.  I assume we can use this
procedure to show energy savings from day-lighting controls under
Building Envelope Trade-Off Options of Std90, Section 5.4 and
Appendix-C.  Can any other computer program, other than DOE2.1E, be used
to show ECB compliance?

	 

	Based on the responses I received regarding day-lighting and
LEED certification, I could cheat and locate the light sensor in a
perimeter space in the DOE2 program run, so that it produces the highest
lighting energy savings results.  The single sensor location could
represent a space with a perimeter depth of 50 ft or more and any floor
area.  I could also use a computer program that produces higher lighting
energy savings than some other computer program.  Title 24 code requires
compliance using specific computer programs and there are instructions
on using the programs so that everyone is on the same playing field.  I
think the location of the sensors and the geometry of the space (without
going into the X,Y,Z coordinates of all the interior walls since there
aren't any in base speculative office building design) should be
considered in energy codes.

	 

	Can 5 cfm per person of outdoor air be used for all types of
commercial (non-industrial) spaces if the filtration system can produce
the same indoor air quality as, say, 20 cfm per person for an office
space?  Does this qualify under "Energy Cost Budget" and "Energy &
Atmosphere - Optimize Energy Performance"?

	 

	I apologize for sounding so ignorant?  Since we have to use
computer programs to show energy code compliance, the developers of the
programs should adjust the program input and output to make it easier to
use the programs to show code compliance.  We were once asked to show
Std90 compliance for an architecturally complex performing arts center
using ComCheck-Plus.  We had to create an equivalent rectangular box
with 5 zones to do this.  It could have been done with DOE2.1E using the
procedure described above.

	 

	Should I send this message to the BLDG-SIM group?  I don't know
who are out there and whether I am making a fool of myself

	 

	Varkie Thomas

	 

	-----Original Message-----
	From: Larry Degelman [mailto:larry at taz.tamu.edu] 
	Sent: Thursday, January 22, 2004 10:43 AM
	To: BLDG-SIM at GARD.COM
	Subject: [BLDG-SIM] Day-Lighting and DOE2.1E

	 

	Just a side note of interest (with no judgment inferred):

	 

	ASHRAE/IESNA Standard 90.1-1999 no longer allows lighting
control credits.  Compliance is based on connected lighting power alone.
With the 1989 Standard, credits could be taken for automatic
controls/sensors and daylighting controls.  (Inference about the
dependability of lighting sensors/controls??? - I don't know.)

	 

	Furthermore, VLT (Visible Light Transmittance) is not considered
in the Prescriptive Envelope Option, but it is considered in the
Envelope Trade-off Option, a la Chapter 5 (Sect. 5.3.2.4 and 5.4).

	 

	Regards,

	===================================== 

	Larry O. Degelman, P.E.                  larry at taz.tamu.edu 

	Prof. Emeritus of Architecture    Ph./Fax: 1-979-696-2506

	Texas A&M University

	=====================================

	 

	-----Original Message-----
	From: postman at gard.com [mailto:postman at gard.com] On Behalf Of
Varkie Thomas
	Sent: Wednesday, January 21, 2004 3:37 PM
	To: BLDG-SIM at gard.com
	Subject: [BLDG-SIM] Day-Lighting and DOE2.1E

	 

	Can day-lighting controls be considered for LEED certification
under "Energy & Atmosphere - Optimize Energy Performance"?  If so where
should the light sensor be located in the space?  Is there any energy
code that allows credit for day-lighting controls? The DOE2 program
allows two light sensors per space.  Supposing the two sensors are
located 5 ft and 10 ft from the window.  Is the average daylight at
these two points used in determining the reduction in artificial
lighting?

	 

	The DOE2 program expects zones to have 6 surfaces defined with
X,Y,Z coordinates and reflectance values for day-lighting analysis.
Ignoring this produces warning messages but the results show a reduction
in artificial lighting energy.  For day-lighting analysis we only enter
into DOE2 the X,Y coordinates of the window origin relative to the wall
and also the wall and window dimensions.  Can we assume that the energy
savings results from the DOE2 program are on the safe side (the actual
energy saved is more) when we use the program without all the surfaces
and coordinates?

	 

	Are there any rules for day-lighting analysis for establishing
energy savings and for comparing the results from different studies?

	 

	Varkie Thomas

	Skidmore, Owings & Merrill LLP

	Tel: (312) 360-4467 (direct)

	 
	 
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