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© Innovative Power Systems
© Doug Shoemaker
© Doug Shoemaker
© Doug Shoemaker
© Innovative Power Systems
© Innovative Power Systems
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reARCH Case Studies
Phillips Eco-Enterprise Center
General Information
Project Name:
The Green Institute at the Phillips Eco-Enterprise Center
Location:
2801 21st Avenue South, Minneapolis, MN
Website:
www.greeninstitute.org
Architect:
LHB
Builder:
Kraus-Anderson
Building Size:
64,000 sq. ft. (Office: 24,000 sq. ft.; Light Industrial:
40,000 sq. ft.)
Building Use:
Office/light industrial
Date of Completion:
September 1999
Ratings and Awards:
| • |
Energy Star Small Business
Award |
| • |
U.S. EPA Award |
| • |
National Award for Environmental Sustainability |
| • |
American Institute of Architects Committee
on the Environment 2000 Earth Day Top 10 |
| • |
President's Council on Sustainable Development/Renew
America |
| • |
City Business Best in Real Estate
(1998) |
Overview
The Phillips Eco-Enterprise Center (PEEC)
is the result of a cumulative effort to reinvest in the Phillips
neighborhood of Minneapolis. After the challenges of EPA superfund
cleanup and an incinerator was prevented from being constructed
in the area, the Green Institute was formed with community advocates
to develop a commercial office space and light industrial facility
to house organizations sharing visions for addressing environmental
and social justice issues. The building helped pioneer green building
and renewable energy approaches in Minnesota. The 34 kW solar electric
system installed on the building is one of the largest in the state.
This solar electric system allows the Green Institute to provide
site-generated renewable energy for a portion of the power used
by the tenants. Along with several integrated strategies, the PEEC
is operated by the Green Institute and has continued to serve as
a demonstration site for educating visitors about sustainable practices
and clean energy production.
Building Performance
Effective Energy
Use Solutions:
| • |
Part of the design approach for the building
was the sharing of facilities such as conference rooms and
office equipment for the tenants. This reduction in systems
and space reduced the energy use for climate control and power,
as well space requirements of the building. Zoned systems
for heating and cooling allowed for individual offices to
maintain climate control isolated from the main corridor and
other offices. |
| • |
Placement of a prominent stairway at the
entrance with the elevator set further in the building was
intended to encourage reduced use of the elevators for energy
conserving purposes and to increase the health of occupants
and visitors. |
| • |
Shared loading docks and a main corridor
in the light industrial section of the building also reduced
the number of bay doors opening and closing to the outside
providing more controllable interior condition. |
| • |
Other strategies include Low-E
glazing, solar-tracking skylights, high-efficiency lighting,
geo-thermal heat pump system, energy recovery ventilation,
and an energy management system. |
Orientation:
Main office spaces face northwest, light industrial wing faces southeast
Daylighting Strategies:
The office spaces have a combined approach for bringing in natural
daylight into the building, utilizing windows and white, reflective
paints to reduce electric lighting. The front atrium allows light
to penetrate into a portion of the open space plan offices through
windows in the walls inside the building. Clerestory windows also
bring natural light into the other office spaces. In the light industrial
section of the building, solar-tracking skylights bring light deeper
into the building. The main corridor is almost entirely naturally
day-lit.
Shading of Structure:
Solar array shades rooftop and upper western side windows
Climate Control Systems:
A ground-source pump system provides heating/cooling for office
space and natural-gas-powered forced air for the light industrial
portion of the building.
Backup Heating/Power:
48-hour emergency systems battery backup
Renewable Energy System Information
Solar System Description
and Size: After construction, the Weidt Group developed
an energy study comparing the cabin with a code-based building.
| • |
The 34 kW solar electric three-phase
system is mounted both on the rooftop with a 30 kW array facing
southeast, and with a smaller 4 kW array on the upper southwestern
wall providing shading on the structure and windows. The net-metered,
grid inter-tied system has a 48 volt battery backup. This
system allows the Green Institute to sell back power to the
utility company on weekends when power use is lower, as well
as have an uninterrupted power source with the battery providing
600 amp-hours of backup power to computer, security, and phone
systems. |
| • |
System Components: Amorphous (thin
film) silicon BP MST 43 watt modules, 696 modules are on the
rooftop, with 92 modules on the southwestern wall. 13 Outback
charge controllers, 12 Outback inverters, and 48 volt battery
make up the balance of systems that convert the DC current
energy from the solar collectors to AC current that matches
with the needs for selling back power to the utility company. |
Solar System Cost:
$195,000
Financial Incentives/Donations:
MN Department of Commerce provided $68,000 in rebates ($2,000/kW);
BP Solar donated 1,200 modules (some sold to other community based
solar projects to reduce cost); and 1,000 hours of volunteer labor
contributed during the installation phase for hauling panels to
the rooftop, mounting the racks and panels.
Payback:
32 years
Date of Installation
Completion: 2005
System Designer/Installer:
Innovative Power
Systems (IPS)
Estimated Amount
of Energy Delivered by System: 40,000 kWh/yr
Percent of Building's
Total Energy Use Provided by Solar: 25%
Motivation for Installation
In addition to the environmental benefits associated
with decreasing Minnesota's dependence on coal and other fossil
fuels, the Green Institute's motivations for developing its PV system
included:
| • |
Planning an installation that
was highly visible to the community, from the ground and by
commuters on the Hiawatha Light Rail Transit line. |
| • |
Connecting renewable energy projects with
local community revitalization opportunities. |
| • |
Demonstrating how local businesses can utilize
renewable energy. |
| • |
Diverting the need for new power stations
to cover peak demand periods by selling excess PV electricity
back to the utility. |
| • |
Having a system that Minnesota utility companies
and state policy makers can use as a successful business model
for planning future projects. |
| • |
Jumpstarting the marketing of Green Power
to rate payers and invested industries. |
(Source: PEEC
Solar Factsheet 2007 courtesy the Green Institute)
Lessons Learned
Part of the process of pioneering new concepts
and technologies includes a level of learning what works and what
needs further development. At the time of installation, the systems
available for balancing the power conversion of such a large solar
electric system required the inclusion of a battery backup.
Based on the improvements of today's technology,
Carl Nelson, one of the staff interviewed from the Green Institute,
suggested that they would exclude batteries if doing the system
again. Nelson went further to say that, "batteries require
ongoing maintenance and replacement, and are the weak environmental
link, having the most environmental impact when utility grid access
is available. The lesson here is to not do a battery system if you
do not have to in an urban setting."
A different aspect of the solar electric system
design that Nelson said would have been included was a monitoring
system to get performance data. As the Green Institute passes on
its utility costs to its tenants, this system interface would simplify
metering and billing, which is challenging when retrofitting the
system.
In an effort to incorporate new technologies
at the time, solar tracking skylights were included in the original
design. Due to climatic conditions they did not perform well. The
tracking systems had a built-in battery, which got discharged during
the winter. The systems were designed originally for California
climate. Solar charged batteries were designed for lower latitudes.
The Minnesota winters did not provide enough sun to keep the batteries
functioning, and so a different system had to be retrofitted.
Other Sustainable Features
Sustainable features include: native prairie
restoration, on-site storm-water retention/biofiltration, green
rooftop, Midtown Eco-Yard, burnished blocks, elimination of dropped
ceilings, design for disassembly and adaptive reuse, pre-cast concrete
panels, local suppliers, construction site recycling, Low-Emissions
paints, reused materials. See www.greeninstitute.org/buildings
for more sustainable features.
Solar Electric Pollution
Offsets:
| • |
30 tons CO2/year |
| • |
180 lbs. NOx/year |
| • |
164 lbs. SO2/year |
| • |
Several lbs. of Mercury |
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