GSA has implemented VRF technology in 10 projects, according to Kevin Kampschroer, director of GSA’s Office of Federal High-Performance Green Buildings.
BUILDINGS content director Chris Olson spoke with Kampschroer about three retrofit projects: the Wayne Aspinall Federal
Building and U.S. Courthouse in Grand Junction, CO; the Bishop
Henry Whipple Federal Building in Fort Snelling, MN; and the
Byron Rogers Federal Building in Denver.
What has been GSA’s experience
with VRF retrofits?
I’ll mention three projects because
each is interesting in its own way.
The smallest is the Aspinall build-
ing, which is the first building on
the National Register of Historic
Places to achieve net zero. It uses a
combination of VRF, ground source
heat pumps, rooftop solar, efficient
windows, and extraordinary atten-
tion to increasing the envelope insu-
lation from the inside as the historic
exterior can’t be tampered with.
This is a particularly good facility for the application of
variable refrigerant flow because of its location in what is
essentially a high desert. For half of the year there is a large
temperature differential between the east and west facades.
As the sun heats up the east side of the building, it requires
cooling while the west side calls for heat. Variable refrigerant
flow allows you to move heat from one side of the building to
the other, making everyone more comfortable.
The building’s heat pumps make a great combination
with VRF. Geothermal wells and VRF are like a marriage
made in heaven.
Has GSA used this VRF/geothermal combination on
Yes, the Whipple building in Fort Snelling, MN. It’s a much
bigger building – 618,000 square feet – but it also needed
replacement of the entire HVAC system. It is one of the largest
buildings in our inventory with geothermal wells and VRF.
For Whipple, the east-west orientation was not such a big fac-
tor. Much of the savings from the VRF involves the ventilation.
The energy it takes to push air around a building typically makes
ventilation the largest single energy cost in maintaining building
temperature. Pumping refrigerant in the VRF system is more ef-
ficient than using fans to move air. You can vary the pump speed
and the pump pressure, which saves on energy distribution.
The renovated facility is 72% more energy-efficient, in
part due to the VRF system. The efficiency makes it a
Does your third example also use geothermal wells?
The third example is not ground source. It’s the Byron Rogers Fed-
eral Building in Denver, which was built in 1964. At 620,000
square feet, it’s about
the same size as
Whipple but it’s tall.
Because of its down-
town location, ground
source heat pumps
were not an option.
From an energy per-
spective, the Denver
tion could not be
worse – long facades
on the east and west
and short facades on
the north and south.
Through the day we
need to move heat
from the east side of
the building to the
west or back in the
other direction. By
switching over to VRF,
we save space because
we’re not moving as much air. Instead, we’re moving chilled
water through beams for cooling.
The condensing units are installed within the existing boiler
room. They serve VRF fan coils on each floor, which are the
equivalent of a radiator that heats and cools. And the separation
of heating and cooling from the ventilating system enables us to
concentrate on high-quality, super-filtered outside air.
The retrofit saved a lot of area on every floor by eliminat-ing ductwork running up and down the building. On the top
mechanical level, it was the equivalent of adding a new floor. If
you imagine an 8 ½ by 11 sheet of paper as the cross section of a
duct, you need a pipe about the diameter of a nickel to move the
same amount of heat. That gives you an idea of the space that
you’re saving. B
VRF APPLICATIONS IN THE PUBLIC SECTOR
GSA APPLIES VRF TO DIVERSE BUILDINGS