Empa, in cooperation with Eawag, the Swiss institute for aquatic research, has developed a self sufficient and mobile home SELF. SELF is an independent living unit serving as a test and demonstration platform of forefront technologies for future homes with a special focus on  energy and water efficiency and savings. The unit can be occupied by up to two people, and is furnished with a kitchen and bathroom. SELF is designed to operate completely independent from external electricity and water supply. Electric energy and water are sourced from the atmosphere, by photo voltaic solar harvesting and rain water collection respectively. Heating, cooling and ventilation demands are reduced through optimal building skin insulation, heat recovery and control. Innovative novel appliances are installed to further reduce the energy and water consumption. Through a large degree of water recycling minimal overall water demand is achieved. 

Electric Energy Harvesting

All required electric energy is harvested with photo voltaic (PV) solar panels and primarily stored in lithium ion batteries. The entire roof and the movable sun shade are employed to the this purpose.

The PV area is approximately 20 m² and has a peak conversion power of 3.75 kWel

A lithium ion battery with a capacity of 16.5 kWh is installed in the SELF living unit. This battery is able to cover the SELF electric demand of several days and serve as a buffer storage for the conversion to hydrogen for seasonal storage. All electrical energy converters are interconnected via 230 VAC micro grid and controlled from a programmable logic controller (PLC).

Rain Water Harvesting
Water system with drinking and gray water processing

Clean water is a valuable good. In SELF, collected rain water is filtered and used as drinking water. Waste water from sink, shower and dishwasher is recollected filtered by means of a bio membrane filter and used for all purposes apart from drinking. Through this continuous water recycling process, the total water demand is strongly reduced.