Fronius Ohmpilot Bedienungsanleitung Seite 105

Many heating systems consist of a boiler and a buffer, whereby the central heating sup-
plies the buffer and a control system charges the hot water boiler via a pump. As with ther-
mal photovoltaic systems, the Ohmpilot is also capable of heating the hot water boiler first
and then the buffer, so that the maximum amount of photovoltaic surplus energy can be
stored.
The Fronius Smart Meter records the current power at the feed-in point and transfers the
data to the Datamanager. By controlling the Ohmpilot, the Datamanager adjusts any sur-
plus energy that is available to zero. In detail, this takes place by continuously adjusting
the heating element connected to the Ohmpilot.
For this application, two heating elements are installed, with preference being given to ac-
tivation of the first heating element (10). Only once the maximum temperature in the boiler
(7) has been reached is the second heating element (12) activated in a continuously vari-
able manner, so that the remaining energy can, for example, be stored in a buffer.
If no temperature sensor is connected to the Ohmpilot, after 30 minutes the Ohmpilot at-
tempts to output energy via the first heating element once again. If a temperature sensor
is present, the device switches back to the first heating element as soon as a temperature
difference of 8 °C is reached (compared to the temperature measured prior to switch-over).
This switching can also be used for layering in a boiler/buffer, so that the maximum tem-
perature is reached in the top part of the boiler using minimal energy and the remaining
energy is stored in the lower part of the boiler. By using layering in a storage tank, it is also
possible to store significantly more energy, as a minimum temperature is normally main-
tained in the top part of the boiler. This means that the temperature difference and there-
fore the amount of energy is rather small. In the lower part of the boiler, a high temperature
difference of, for example, 50 °C can be used.
The switching must be realised by an external contactor. If no temperature sensor is fitted,
an external source (e.g. gas-fired heating) must be used to ensure the minimum tempera-
ture is met.
Alternatively, the Ohmpilot can also ensure the minimum temperature. This may result in
electricity being sourced from the grid.
The maximum temperature must be set on the heating element thermostat and on the heat
pump. If heating element 1 (10) does not have a thermostat, the Ohmpilot can also carry
Optional settings on page 116). However,
out this task as an alternative (see chapter
heating element 2 (12) must have a thermostat.
NOTE!
Heating at the same time.
At no point can both heating elements be heated simultaneously.
105