Commercial Architecture January 2018 - 22

PROJECT

geothermal

Cornell's Tech Campus Aims For Net Zero
Geothermal system forms backbone of a versatile HVAC system in the
Bloomberg Center building on Roosevelt Island in NYC.
Jay Egg, Egg Geothermal

even years ago, Mayor Michael Bloomberg requested proposals
from universities for a new or expanded engineering and applied-sciences campus in New York City. Though competition

was stiff, with the likes of Stanford, Columbia, and Carnegie Mellon submitting proposals, Cornell Univ., Ithaca, NY, was awarded the project.
The Bloomberg Center, the education facility on the 12-acre Cornell
Tech campus on Roosevelt Island in NYC, opened in July 2017, welcoming
its first 250 students. The Center is an elegant mix of design features that
include radian- floor heating, dual-purpose modular chiller/heat pumps,
and active chilled-beam cooling, all of which are connected to a decoupled
ground loop. A goal for the building is to earn LEED Platinum status and
net-zero performance.

GEOTHERMAL SYSTEM

GI Energy, New York, was chosen to develop the earth-loop design. The
company has completed numerous projects around the world and is currently engaged in the geothermal design for the new Google campus outside San Francisco.
Cornell's geothermal system uses a vertical-loop design consisting of 80
Above. The Bloomberg Center, on the 12-acre Cornell Tech campus on Roosevelt Island in NYC is an elegant mix of design features
that include radiant floor heating, dual-purpose modular chiller/heat pumps, and active chilled-beam cooling, all of which are
connected to a decoupled ground-loop geothermal system. Photo: Jay Egg

400-ft.-deep vertical boreholes into which close-loop HDPE exchangers
have been inserted. Normally, the boreholes are filled with bentonite grout
to enhance heat transfer and seal the borehole. In this case, the boreholes
were drilled into solid rock with a water-bearing fracture zone below 300 ft.

Below. The geothermal system uses a vertical-loop design consisting of 80,400-ft.-deep vertical boreholes into which closed loop
HDPE exchangers have been inserted (inset). Today, the borehole field serves as a park. Inset photo: Jay Egg

Groundwater movement through the zone enhances the ability of the
HDPE exchangers to extract and reject heat for the 360-ton HVAC system.
Designs such as this are actually fairly common in northern European
locales such as Sweden and Norway (countries that are actively and extensively using geothermal heating and cooling). This unusual, but favorable,
application shows the importance of understanding variables in earth-loop
design. As an example, the city of Drammen, Norway, uses a central river-source geothermal system to heat and cool its 225 commercial buildings,
as well as 65,000 residences.
Could the Cornell project have done something similar to what was
done in Drammen? Yes, that was an option, but NYC authorities having
jurisdiction, and decision-makers across the country for that
matter, do not yet have a sufficient comfort level with placing
heat exchangers in rivers. The
education required to reach
that comfort level is why the
New York state government is
devoting considerable resources
to geothermal-system educa-

COMMERCI A L A RCHI T EC T URE

JANUARY 2018

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