Villa Tannheim - Home of ISES Headquarters

When ISES decided to move its Headquarters from Australia to Germany in 1995 the City of Freiburg offered the Society the Villa Tannheim at a charitable price. In addition, Mrs. Marta Weeks provided a generous donation making the purchase of the Villa possible. Before the old, historically significant building could be occupied a thorough and energy-saving renovation was required. The aim of the renovation was to reconstruct the outer appearance of the patrician building, maintaining the general appearance, while using renewable energy sources to show how a building can be changed to save energy. The Fraunhofer Institute for Solar Energy Systems developed the energy saving concept, with the result of an annual energy saving of 27 tons of CO2.

  • Exterior wall insulation
  • Transparent insulation made with glass attached to a heat-absorbing background to reduce thermal losses
  • Ecologically safe roof insulation, produced from recycled paper, treated to make it inflammable
  • Tripe glazed windows reducing heat loss by 90 %
  • Heating and domestic water supported by a roof-top solar thermal system
ISES continues to improve and expand this performance. In 2006, ISES initiated an ambitious strategy to expand on the existing energy savings strategies and renewable technologies the building uses. In addition to the opened SolarCarpot in 2007, ISES has replaced its existing gas heater with a new pellet heating system in 2008.
Pellets heating oven


The ISES SolarCarport is a shining example of how renewable energy technology can be integrated in the built environment. The design by Freiburg-based solar architect Rolf Disch incorporates the following features:
  • 18 by 6.30 meters hot-dip galvanized steel frame
  • Totaling an area of 113 m2, 108 photovoltaic (PV) modules manufactured by Kyocera, mounted on a diagonal inclination (6° south and 10° east), to maximize sunlight exposure
  • The panels are attached directly to the steel carport frame using the SOLRIF® system
  • Peak capacity of 14.04 kWh of solar electricity
  • The Carport saves about 8.2 tons of CO2 per year
The ISES SolarCarport has been made possible by the generous support of several sponsors. We would like to express our sincere gratitude to these companies:
  • Kyocera Fineceramics GmbH
  • Tritec AG
  • Ernst Schweizer AG
  • Rolf Disch Solar Architect
Solar carport

Pellet Heating System

he new wood pellet heating system is the latest addition to the Villa Tannheim and represents another step towards becoming renewable energy powered and CO2 neutral. The pellet heater replaces the old gas heater and operates in conjunction with the existing solar thermal collectors on the south facing roof of the Villa. With the pellet heater, ISES takes advantage of an ideal combination of solar and bio-energy to meet the Villa’s heating and hot water needs. The new system is made up of the following:
SolvisLino pellet heater boiler with
  • Capacity of 30 kW
  • 93.5% efficiency
  • Using 6 tons of pellets per year – 1 delivery per year
  • Fully Automatic – ignition and operation
 Solvis Max Solar Storage Tank
  • 950 litre capacity
  • Most efficient
The pellet heating system was made possible by generous support from the companies bad & heizung Kreuz GmbH and Solvis GmbH & CO KG. ISES would like to express its sincere thanks to both for making this lasting contribution towards achieving the ISES vision.