The eTherm S (self-sufficient solution -> plug and play solution for small storage tanks) has a heating rod that is modulated by the controller according to the surplus. Due to the design (heating rod in the storage tank), this system is particularly suitable for small drinking water storage tanks.
The eTherm P (self-sufficient, hydraulic station for PV systems from approx. 4 kWp and storage tank from 400 l) has a coordinated system of surplus measurement and power modulation for constant target temperature loading of the storage tank.
The eTherm C (for PV systems from 8 kWp and storage tanks from 500 l) is a powerful hydraulic station for target temperature loading of the storage tank. The eTherm C relies on external energy management, as described above. Representatives of the switching energy managers are for example (switching 3000W, 6000W, 9000W) Solarwatt, Solarlog, Solaredge, SMA etc.