CREJ - Journal

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42 / BUILDING DIALOGUE / MARCH 2015
I n 2008, we were chosen as the electrical de-
sign-build partner for the National Renew-
able Energy Laboratory Research Support Facil-
ity. The Department of Energy and NREL wanted
this building to be the most energy-efficient
office building in the world, and wanted the
building to be net zero, if possible. The term “net
zero” in this case is defined as a building that
achieves zero net energy consumption; the total
amount of energy used by the building on an
annual basis is equal to the amount of renewable
energy created on the site. NREL wanted the Re-
search Support Facility to achieve net zero energy
consumption through the use of renewable energy
sources mounted within the building footprint.
As the electrical design contractor, our job was to
provide the most energy-efficient electrical solu-
tion possible. The design team of RNL Design and
Haselden Construction led the effort by designing
a building 60 feet deep with an east-west orienta-
tion, which would maximize the opportunity for
harvesting daylight and provide for an open office
design, which allowed the daylight to be cast deep
into the building.
Exploring Innovative Lighting System Options
Our primary focus during the design of the RSF
was the building lighting system. Typically, the
building lighting system consumes 30 percent to
40 percent of the energy used by the building. Our
goal during the design phase was to achieve a level
of energy efficiency never before realized. We did
not assign an energy goal because we did not want
to limit our thinking as we approached this project.
Our first step was to consider the LED fixtures. LED
was just beginning to be considered for commer-
cial projects similar to the RSF and, in my opinion,
was the lighting “rage” at that time. The problem
was that in 2008, LED fixtures were only capable of
producing 80 lumens per watt. Fluorescent lamps
produced 90 or 95 lumens per watt at that time and,
from an energy use only standpoint, were the only
choice for the lighting system in the RSF. Having
decided on a fluorescent solution, we examined T5
versus T8 lamps and discovered – to our surprise
– that the T8 lamp ballast combination was the
most energy-efficient solution. The primary light-
ing source in the RSF is a 25-watt, T8 direct-indirect
linear fixture.
Engineering Lighting Controls to Maximize Efficiency
The next system we examined was the lighting
control system. We designed an elaborate lighting
control scheme that maximized the amount of
harvested daylight and created micro occupancy
zones to assure the most energy-efficient lighting
Jim Dent, LEED
AP BD+C
Preconstruction
Manager,
Weifield
Group
Contracting
Let in the light: NREL RSF’s open office area
TRENDS in Lighting Design