The eTank is part of a heating and cooling system that functions on the basis of a brine water heat pump. Along with the dynamic energy manager, layered storage (water-based) and a standard solar thermal system, the e-Tank can produce heat, as well as provide cooling power, at highly efficient levels.

The eTank can also buffer the yield of other regenerative heat sources over long time periods. These sources include: exhaust air units and/or chimneys with heat recovery, water cooled photovoltaic systems and process or emission heat.