The Ekihouse: An energy self-sufficient house based on passive design strategies

• Energy self-sufficient house.
• Full integration of active solar technologies and passive design strategies.
• Industrializable and timber-based modular construction.

The Ekihouse is an industrialized solar house prototype, designed and developed by the University of the Basque Country for the SOLAR DECATHLON EUROPE 2012 competition held in Madrid (Spain). The building design strategies are based on the full integration of active—passive solar technologies and passive design criteria in order to achieve an energy self-sufficient proposal, providing high quality of life to its occupants. Despite its intentionally small surface area (54.6 m2), the house can be adapted to suit a wide range of lifestyles thanks to its flexible, multifunctional open plan design that can be visually and physically expanded outdoors by removing the northern and southern glazed façades (PVC joinery and 0.9 kW/h m2 °C glass). For ease of transportation and assembly, the Ekihouse consists of a modular CLT structure system (two 12.60 m × 3 m modules) that supports the photovoltaic roof (10 kWp) which functions as a canopy to protect the southern facade from direct solar radiation thereby reducing overheating problems in the building interior. In order to control the indoor temperature, PCM panels are mounted in the ceiling. When passive strategies are insufficient in extreme conditions, the house is also equipped with a ventilation and air-conditioning system that allows a 90% energy recovery. Furthermore, an outdoor evaporative cooling system helps lower the ambient temperature by up to 4 °C. A rain and grey water treatment and purification system is also installed. The operation of all this active technology is controlled by an optical domotics system.