Storing electricity is expensive and inefficient but storing heat has significant benefits. That is why we convert the solar power to electricity after the storage instead of before. Thermal Energy Storage (TES) is the obvious and optimal choice for electricity on-demand all hours of the day.
A Phase Change Material (PCM) is liquefied in the container through direct illumination of the container wall by the concentrated solar heat. During discharge, heat is transferred from the PCM to a heat transfer fluid (HTF).
The HTF transfers heat from the thermal storage to the Stirling engine heat exchanger where the Stirling engine working-gas is heated and cooled off by ambient air, and thereby runs the engine.
The Thermal Energy Storage (TES) is the very heart of our new solution. And it’s made out of metal. Since the greatest energy recovery is obtained in the conversion phase we have chosen an aluminum alloy for its very specific phase changing characteristics.
Choosing an aluminum alloy as the heat storing material is no coincidence, but the result of long and devoted research and development. The high degree of energy density enables local energy production around the clock in remote locations wherever the sun is reliable.
Aluminum has excellent heating storage ability, making it possible to use the Stirling engine to withdraw electricity locally, at full effect, all the dark hours of the day. At a very competitive cost.
Aluminum is the third most common element and the most common metal in the earth’s crust. The environmental impact of aluminum is primarily due to the energy supply in manufacturing. This will be reduced to a minimum when using recycled aluminum, produced exclusively with electricity from wind and hydro – and of course solar energy in a near future.