Fronius Ohmpilot Operating Instructions Manual page 108

(14)
(15)
Many heating systems consist of a boiler and a buffer, whereby the central hea-
ting supplies the buffer, and a control system feeds the hot water boiler via a
pump. As with thermal 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 inverter. By controlling the Ohmpilot, the inverter adjus-
ts any surplus energy that is available to zero. In detail, this takes place by conti-
nuously adjusting the heating element connected to the Ohmpilot.
For this application, two heating elements are installed, with preference being gi-
ven to activation of the first heating element (10). Only once the maximum tem-
perature in the boiler (7) has been reached is the second heating element (12) ac-
tivated in a continuously variable 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 attempts to output energy via the first heating element once again. If a
temperature sensor is present, the device switches back to the first heating ele-
ment 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 maxi-
mum temperature 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 laye-
ring in a storage tank, it is also possible to store significantly more energy, as a
minimum temperature is normally maintained in the top part of the boiler. This
means that the temperature difference and therefore the amount of energy is ra-
ther 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 sen-
sor is fitted, an external source (e.g. gas-fired heating) must be used to ensure
the minimum temperature 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. If
heating element 1 (10) does not have a thermostat, the Ohmpilot can also carry
out this task as an alternative (see chapter
However, heating element 2 (12) must have a thermostat.
NOTE!
Heating at the same time.
At no point can both heating elements be heated simultaneously.
108
Automatic circuit breaker max. B16A
Ferrite (included in scope of supply)
Optional settings on page 122).