A salt hydrate fireplace is among the energy-efficient features of a floating house planned for Lake Geierswalde near Hoyerswerda, Germany.
The Fraunhofer Institute has partnered with the Technical University of Dresden and the Technical University of Brandenburg and local businesses on the two-story houseboat, which will sit on a 13x13-meter steel pontoon. Solar cells will be integrated in the building envelope; lithium polymer batteries will store the collected energy.
The project is scheduled for completion in 2017. Research in Germany describes the home's heating and cooling systems:
"A salt hydrate fireplace provides heat on cold winter days: above the fireplace there is a tub filled with water and salt hydrates.
" 'When the fireplace is on, the salt hydrates liquefy and begin to absorb heat,' Dr. Burkhardt Fassauer [of the Fraunhofer Institute for Transportation and Infrastructure Systems] explains. When the salt hydrates are completely liquefied, the thermal energy can be stored almost indefinitely. In order to release the heat when required, radio-based technology is used to induce crystallization. ...
"However, a fireplace is not enough to heat the house during the winter. This is where a zeolith thermal storage unit in the pontoon can help: the zeolith minerals are dried during the summer – a purely physical process in which heat is stored.
" 'In winter, the moist air is enough for the storage unit to give off heat,' Fassauer explains.
"An adiabatic cooling system provides for cool air in the summer. Unlike conventional air conditioning systems, it does not require electricity but uses the principle of evaporative humidification to cool. A surface on the side of the house is landscaped and moistened and the process of evaporation then cools the building envelope."