Overlooking the Mississippi River in downtown Saint Paul, Minn.,
is one of the premier convention centers in the Midwest: Saint Paul
RiverCentre. Since it opened in 1998, the 162,000-sq-ft facility has hosted
a wide variety of meetings, trade exhibitions, festivals and other events,
including the 2008 Republican National Convention and President George
W. Bush’s 2001 energy policy address. It is owned by the city of Saint
Paul and managed, together with the adjacent Xcel Energy Center and
Roy Wilkins Auditorium, by Saint Paul Arena Co. A customer of District
Energy St. Paul from the start, Saint Paul RiverCentre is known as a model
of sustainability practices that include its most recent green project: a
groundbreaking solar thermal installation.
Saint Paul RiverCentre relies on hot water district heating and
chilled-water district cooling from District Energy St. Paul. In March, District
Energy partnered with the convention center to launch the Midwest’s
largest solar installation. The project consists of 144 solar thermal
collectors on the Saint Paul RiverCentre roof, which peak at 4.09 MMBtu/hr
of thermal energy, reducing carbon dioxide emissions by 900,000 lb each
year. The solar energy produced is primarily used by the convention center
for space heating and domestic hot water. Any excess energy is exported
to District Energy’s downtown hot water district heating network. The
624 MMBtu-hr system already receives the majority of its energy from a
biomass-fueled combined heat and power plant.
The solar thermal project was made possible through the U.S.
Department of Energy (DOE) Solar America Communities program in
partnership with the city of Saint Paul, the city of Minneapolis and the
Minnesota Division of Energy Services. The city of Saint Paul secured a
$1 million DOE Market Transformation grant matching $1.1 million in
funding from District Energy St. Paul.
Preliminary design began in December 2010, and District Energy
selected Saint Paul’s TKDA, along with the firm’s partner Ramboll, to
assist with design and engineering. Saint Paul RiverCentre met the
technical requirements for installation, with additional panel structural
considerations for wind, ice and snow loading specifications.
Solar panel selection was crucial to maximize the $2.1 million budget
and 30,000 sq ft of roof space. ARCON Solar collectors from Denmark were
chosen for their high performance. Most importantly, these panels have a
starting efficiency of more than 0.70, minimal thermal losses and can reach
temperatures up to 200 degrees F.
After panel selection and final design, local contractors spent a
cold, snowy winter installing the steel frames, piping and collectors. The
convention center’s internal systems were upgraded for the solar heat source
in conjunction with District Energy’s supply of hot water to the building.
Saint Paul RiverCentre
and District Energy St. Paul:
Courtesy District Energy St. Paul.
An installation of 144 solar panels atop Saint Paul RiverCentre generates
4.09 MMBtu/hr of thermal energy annually that is used at the convention
center and by District Energy St. Paul.
After three months of operation, the system had outperformed
expectations during available solar production hours. Positive performance
data have led more than a dozen other cities and universities to inquire
about developing similar projects that will rely on this system’s experience
to lead the way. In particular, there is great potential for solar installations
integrated with steam-based district systems.
As the solar success moves forward, so does the convention center’s
broader sustainability initiatives, including its ‘buy green’ program
(supporting the purchase of recycled, compostable and/or high-efficiency
products) and a multifaceted waste reduction program that significantly
increased recycling and introduced composting in public areas. Last year,
Saint Paul RiverCentre launched a new “ 80-20 in 3” initiative to cut the
facilities’ carbon footprint by 80 percent and become 20 percent more
efficient than average within three years. A major lighting replacement and
upgrades to HVAC equipment, doors and window coverings are all planned.
District Energy St. Paul and Saint Paul RiverCentre are proud to
collaborate on solar and sustainability, and are excited to see how the new
solar thermal installation will further advance the possibilities for integrated
For more information, visit www.solarsaintpaul.com or contact District
Energy St. Paul Project Manager Nina Axelson or Project Engineer Ray Watts
To view other Customer Closeup profiles, visit District Energy magazine
online at www.districtenergy-digital.org/districtenergy/2011Q2 and
search “Customer Closeup” in all issues.