Arch Solar

Little River Flower Farm

For over 18 years Bruce and Nancy Stedman have worked their land year-round. They are certified organic, in-ground growers that sell via Whole Foods, CSAs and direct to Portland area restaurants.

Little River Flower Farm wanted to expand production while reducing significant energy bills associated with heating and lighting costs. Over the past three years, Bruce and Nancy lost several greenhouses to the considerable weight of snow that accumulates during Maine winters. They commissioned ArchSolar to build a structurally sound greenhouse that would reduce their energy inputs while raising crop outputs. They wanted a solution that was sustainable both environmentally and economically, and would allow them to switch to renewable energy as well as generate their own electricity.

Building the PV Greenhouse at Little River Flower Farm

Design Considerations

•  Glazing needs to maximize light infiltration, insulation and structural rigidity

•  Structure needs to withstand 70lb/s.f.  snow load and 105 mph winds

•  Structure needs to generate electricity, use renewable heat resources and minimize conductive losses


Building Features

•  Fiberglass I-Beams: Many times less conductive than carbon steel, these outperform steel from a thermal standpoint. The I-Beams allow us to span 45 ft in a single span.

•  Polycarbonate Building Skin: This feature allows for important light to come into the building and incorporates active solar thermal heating into the structure.

• Phase Change Materials: These thermal storage mediums are integrated throughout the building to absorb heat harvested from the south wall, and provide cooling in summer months.

•  Integrated  Climate Control Sensors:  These monitor heat, relative humidity and carbon dioxide throughout the building.

•  21.4 KWp array of Flexible CIG Solar Panels produced by Miasolé.


Project Highlights 
45’ wide “clear span”x 18’ high x 140’ long14.4 KWp solar array built into greenhouse roof
6,400 sf of production areaR-2.4 glazing
25’ radius pultruded fiberglass arches
Biomass fueled root zone radiant heat system
Built to withstand 70 lb snow load, 105 mph windPhase change materials for heat storage
Miasolé flexible CIGS solar panels30% Investement Tax Credit for PV array and solar thermal system
Different sections of solar covering 17%, 25%, 33% respectivelyRecipient of 25% USDA REAP Grants for Biomass and PV

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