Efficiency increase in the entire system thanks to the eTank’s low plant expenditure figure (ep-count) of < 0.3.

In a complete economic overview of the system, the focus lies on the unit’s expenditure figure – the ep-count. The ep-count describes the relation of heating warmth demand to the used primary energy. It takes into account the kinds of fuel used, the regenerative energy applied and the losses caused by storage, distribution and the transfer of energy.

We aim for the lowest possible ep-count. Conventional units (gas condensing boiler with solar heating support) reach an ep-count of ca. 1.1. A very efficient unit consisting of a heat pump, geothermal drilling, solar unit and controlled airing can reach an ep-count of ca. 0.7.

The ep-count stands in direct relation to the running costs and the environmental friendliness of the system. It has a linear influence on the primary energy demand of a building and thereby on the energetic evaluation according to the energy saving ordinance (EnEV). The intrinsic value and the economical evaluation of a new building or a renovation are decisively defined by the ep-count.

Graphic: Primary energy demand of a 50 kWh/m2 heating warmth demand and 1100m2 living space. (example calculation of a multiple family house)