Home builder IGC, based in southwestern France, is working with Liten on technologies for tomorrow's energy-independent homes under a research project titled 100%solaire. The goal is to develop new home designs that ensure optimal occupant comfort year-round at the lowest possible cost. A novel cooling system that can be added to the original home heating system for just a small additional cost was developed at the service building at INES, France's national solar energy research institute in Chambéry, and patented. Validation testing was completed in Chambéry before the system was sent to Bordeaux for summertime testing at an experimental building site.

Here's how the surprisingly simple system works: a wall of hollow clay bricks is connected to a water tank under the house. At night, the water is channeled to the brick wall, where it is cooled by convection, radiation, and evaporation. During the day, the cold water flows through the under-floor heating system, cooling the ambient air. At the end of the day, the water—hot again—is channeled back to the brick wall and the cycle begins again.

Liten designed and developed the system and the management software used to adjust the cooling strategy to forecasted weather conditions. Researchers at Liten are now working on a similarly economical heating system for winter.