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

[Mike Tillou]

Varkie,
 
The answer to your question is Yes.  LEED is going to allow the inclusion of daylighting as part of EA1.  They have been working with ASHRAE to develop Appendix G for ASHARAE 90.1-2001 Energy Code.  Appendix G provides a methodology for modeling the energy performance of a building using ASHRAE 90.1-2001 as the baseline.  I think (don't quote me) the intent is that LEED will adopt Appednix G as an acceptable methodology for determining energy performance.  The methodology addresses many of the issues that are not addressed by the Cost Budget Method to show code compliance.  Appendix G will not replace the Cost Budget Method as a means for showing code compliance.  
 
Appendix G has not been officially released by ASHRAE, I am sure it will be soon though.
 
Here is some of what it says about the simulation of lighting systems that pertains to your question.
 
(f) Credit may be taken for the use of automatic controls for daylight utilization but only if their operation is either modeled directly in the building simulation or modeled in the building simulation through schedule adjustments determined by a separate daylighting analysis approved by the rating authority.
(g) For automatic lighting controls in addition to those required for minimum code compliance under 9.2, credit may be taken for automatically controlled systems by reducing the connected lighting power by the applicable percentages listed in Table G3.8. Alternatively, credit may be taken for these devices by modifying the lighting schedules used for the proposed design provided credible technical documentation for the modifications are provided to the rating authority. Table G3.8 is shown below.
 	  	 Non 24 hr.
 	  	 &
All
Automatic Control Devices(s)
<=5,000ft2
Other
(1) Programmable timing control
10%
0%
(2) Occupancy sensor
 	 15%
10%
(3) Occupancy sensor and
programmable
timing
 	
control
 	 15%
10%
Notes: The 5,000 ft2 condition pertains to the total conditioned floor area of
the building.
 	  	  	
					
G4.4 Baseline Lighting Systems. Lighting power in the baseline building design shall be determined using the same categorization procedure (Building Area or Space Function) and categories as the proposed design with lighting power set equal to the maximum allowed for the corresponding method and category in 9.3. No automatic lighting controls (e.g., programmable controls or automatic controls for daylight utilization) shall be modeled in the baseline building design, as the lighting schedules used are understood to reflect the mandatory control requirements in this standard.
Hope this helps.
 
Michael Tillou, PE
etc Group, Inc.
PO Box 749 
North Adams, MA 01247
413-664-9070
 

________________________________

From: postman at gard.com on behalf of Larry Degelman
Sent: Thu 1/22/2004 9:43 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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