620 DualSun hybrid panels for a energy-positive high school - Carquefou (FR)

  • 2017
  • Carquefou, France
  • Power output : 173.6kWp + 250.48kWth
  • Panels : 620 hybrid panels

620 DualSun solar panels (a little over 1000m2) were installed at the new energy-positive high school in Carquefou, France near Nantes on the Atlantic coast.  

The technology was chosen deliberately: “we selected DualSun for the double-benefit of cooling the photovoltaic cells to increase electricity efficiency and generate hot water simultaneously”, confided Jerome Diot, head of Sustainable Development and Energy at Egis, the design firm in charge of this project.  

The Pays de Loire region followed the HQE (High Environmental Quality) label for the design of this new high school.  The high school is designed such that it generates more energy than it consumes! While the energy consumption of the building is estimated at 53 kWhep/m2/year, the production of renewable energy is estimated at 60.8 kWhep/m2/year.

The DualSun panels play a major role in the energy system of this building.  The thermal energy generated by the panels is sent to the Aquaciat heat pumps for the heating and the HELIOPAC heat pumps for the hot water.  The coupling of the panels with water-water heat pumps allow to increase the efficiency of the heat pumps with a renewable source.

The fact that there is zero risk of overheating with the DualSun panel was also a major design advantage for this project: “the panels are auto-regulated to not heat past 80°C.  As the panel is not very insulated on the backside, it is designed to not overheat”, Jerome Diot explains.

As for the solar photovoltaic production of the DualSun panels, the electricity is directly consumed in the building.

This new “high school of the future” opened its doors in September 2017 to 900 students and is an exemplary model of what can be done for buildings with solar energy.

Technical information

Characteristics Energy-positive high school
Number of panels 620 DualSun hybrid panels
Power output 173.6kWp + 250.48kWth
Rooftop installation Inroof integration (EASY ROOF system), south facing, 30° angle
Thermal system For heating: 530 DualSun panels, 2 Aquaciat 100 kW heat pumps, 3 vertical storage tanks (3 x 60,000 L) ; 300 kW wood boiler with 2 1,000 L storage tanks For hot water: 90 DualSun panels, 2 HELIOPAC 11 kW heat pumps
Photovoltaic system Self-consumption of the electricity for the building, surplus is sent and sold to the grid