Heating with solar cells and zeolite – Long-term storage
Heating with solar cells and zeolite – Long-term storage
Researchers at the University of Stuttgart in Germany are set to test a solar heating system with long-term storage capabilities as part of the “Solspaces”, a three-year programme launched in March 2012.
The system is based on a solarthermal system operating in conjunction with a sorption tank, where the heat collected by the solar cells during the warmer months is stored until it is used when temperatures drop.
The Solspaces concept can help reduce the storage space required for solar thermal systems and effectively address the issue of retaining heat for future use.
It is based on a thermochemical heat storage tank with a density three to four times higher than that of water and improved thermal insulation, which allows forstorage in a smaller space with fewer heat losses compared to conventional systems that use water as the storage medium.
The process also utilises the porous mineral zeolite
, which has high energy density, a low drying temperature and the capacity to absorb large quantities of water vapour.
During the winter months, the zeolite
acts as an adsorbent material that ‘collects’ moisture from the atmosphere inside the tank. The combination of water vapour with the adsorbent material produces thermal energy which is used to heat the building.
During the summer months, the process is reversed and the solar cells heat the air circulating in the tank to 180 degrees Celsius.
Through this process, water molecules are expelled, allowing the adsorbent material to dry out and prepare to reabsorb heat. The research team maintains that the process has the potential to virtually eliminate heat loss, as it does not rely on maintaining water at high temperatures in the tank throughout the year.
The experiment will be carried out in a prefabricated house known as ‘Flying Spaces’, provided by the German company SchwörerHaus.
The building has a floor area of 48 square metres and was selected because its size is ideal for the experiment.
The German Ministry for the Environment has funded the programme with 650,000 euros, with completion scheduled for 2015.
http://www.econews.gr/2013/12/04/thermansi-zeolithos-iliakes-108963/