Fronius PVI1903OHM Operating Instructions Manual page 98

(10)
(11)
(12)
(13)
(14)
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
thermal photovoltaic systems, the Ohmpilot is also capable of heating the hot water boi-
ler 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
activation of the first heating element (9). Only once the maximum temperature in the
boiler (6) has been reached is the second heating element activated 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 sen-
sor is present, the device switches back to the first heating element as soon as a tempe-
rature 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
maintained in the top part of the boiler. This means that the temperature difference and
thus the amount of energy is rather small. In the lower part of the boiler, a high tempera-
ture difference of, for example, 50 °C can be used.
Both the first and the second heating element can be 1-phase or 3-phase. For two 3-
phase heating elements, see
an external source (e.g. gas-fired heating) must be used to ensure the minimum tempe-
rature 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 (9) does not have a thermostat, the
Ohmpilot can also carry out this task as an alternative (see chapter
on page 112). However, heating element 2 (11) must have a thermostat.
NOTE!
Heating at the same time.
At no point can both heating elements be heated simultaneously.
98
Buffer
Heating element 2 (max. 9 kW)
Residual current circuit breaker
Automatic circuit breaker max. B16A
Ferrite (included in scope of supply)
Application example 6. If no temperature sensor is fitted,
Optional settings