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

Varkie Thomas Varkie.Thomas at som.com
Thu Jan 22 14:41:02 PST 2004


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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