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@xxxxxxxxxxxx'
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@xxxxxxxxxxxx]
Sent: Thursday, January 22, 2004 10:43
AM
To:
BLDG-SIM@xxxxxxxx
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@xxxxxxxxxxxx
Prof.
Emeritus of Architecture Ph./Fax:
1-979-696-2506
Texas
A&M University
=====================================
-----Original
Message-----
From:
postman@xxxxxxxx [mailto:postman@xxxxxxxx] On Behalf Of Varkie Thomas
Sent: Wednesday, January 21, 2004 3:37
PM
To:
BLDG-SIM@xxxxxxxx
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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