Tenant space in
Center is designed for
solar DC-to-DC power.
“We simply ask, ‘Why do double—or more—the conversions
from DC to AC to DC?’” Patterson said. “The inherent inef-
ficiency of low-current, low-voltage conversions waste power
from the single digits to as high as 20 percent, depending on
equipment and setup.”
Patterson also said AC 60-hertz (Hz) power significantly
complicates source integration (synchronization) and phase
control in a digitally controlled world, while DC (commonly
“At this level [24V] the power is touch-safe, so you use
exposed busses and eliminate ground wires,” he said. “The wir-
ing is also less expensive and easier to install. DC systems also
better accommodate digital electronics. Like we are seeing in
lighting, we’d like to see the electrical world go digital.”
Even so, Patterson said AC power has its place.
“With relatively few modifications, traditional AC bulk power
[the grid] will continue as a key electricity production and trans-
mission resource,” he said. “Technologies like induction cooking
and wireless power charging that use AC [albeit not fixed 60 Hz]
will also be important. We need both AC and DC electricity but
in the right form for the right job and in the right place.”
Right form, right job and right place influenced how DC/DC
factored into the development of a product that served as the
germination of the EMerge Alliance and its standards.
“Skidmore, Owings & Merrill LLP [SOM], Philips Light-
ing and Armstrong World Industries had an idea,” Patterson
said. “SOM was saying to Philips, ‘You’re developing LEDs as
a broader based lighting source. And, Armstrong, you are doing
innovative things with ceilings and other interior architecture.
What if we bring them together in an innovative, smart way that
delivers lighting and energy dividends?’”
That led to discussion with Nextek Power Systems, Detroit,
which designed the new product to run with DC and solar
energy. The first standard for “Occupied Space” was modeled
after the collective work on the solar-LED-ceiling concept.
The resulting product and first EMerge certification was Arm-
strong’s DC FlexZone, a DC-powered ceiling-suspension-grid
system offering plug-and-play flexibility for LED lighting, con-
trols and other building operations. DC main beams run through
the grid-ceiling system. Twelve major lighting and controls
manufacturers have products compatible with FlexZone.
Today, EMerge is also working on whole-building/campus
energy use in nonlighting systems such as data centers/IT;
heating, ventilating and air conditioning (HVAC)/air handling;
plug loads; desktop IT; and other power consumers.
A DC/DC focus
Nextek’s office is located in the Next Energy Center, called
“a living laboratory for advanced energy and transportation
technology development.” Working with the center, Nextek
helped create the NextHome living lab, which allows companies to develop and commercialize DC technologies. The lab
is equipped with Nextek’s Direct Coupling power distribution
platform for DC power. The DC modular home features appliances, fast-charging (Level 3) electric vehicle charging stations,
energy storage, lighting and photovoltaic HVAC.
In another DC-to-DC project, Nextek had great success
without incorporating green energy or storage.
“Our work on an office building for the state of Michigan in
Flint consisted of a wireless, low-voltage mesh network featuring
1,200 nodes that provide control for the entire 100,000-square-
foot building,” said Paul Savage, Nextek CEO. “This project is all
direct current without on-site solar or batteries.”
Savage said his firm works to achieve a 10–42 percent
energy savings on all of its DC-to-DC projects.
EMerge has more than 100 organizations, including universities and national labs (e.g., Lawrence Berkeley National Labs),
assisting in research and development. Lawrence Berkeley’s
interest in DC-to-DC has led to a collaboration with the Electrical Training Institute.