Fronius Ohmpilot - Heater Selection and Charging Time Calculation

Selection of heater
1-phase heater Controlled in a continuously variable manner from 0.3 to 3 kW
-
Resistive load (no electronic temperature limiters, fans, etc.)
3-phase heater Controlled in a continuously variable manner from 0.3 to 9 kW.
-
Equal load distribution on all 3 phases (e.g. 3 x 3 kW).
-
If a mechanical temperature switch is being used, it must switch all 3 phases
simultaneously.
-
Purely resistive load (no electronic temperature limiters, fans, etc.)
-
Neutral conductor must be connected
N L2L1 L3
Temperature limitation
A mechanical temperature switch sim-
plifies commissioning and use. If no
mechanical temperature switch is
available, a temperature sensor can
also be connected to the Ohmpilot.
This limits the maximum temperature
(see chapter "Temperature limitation"
on page).
Example for cal-
culating the
charging time
500 l boiler, heater is fitted at the very bottom of the boiler,
temperature spread 45 - 60 °C = 15 °C
4.5 kW heater
Possible stored energy = 500 l (storage tank capacity) x 1.16 Wh (energy require-
ment per litre) x 15 °C (temperature spread) = 8.7 kWh. If the heater at full
power (4.5 kW), heating up takes approximately 2 hours.
For optimum utilisation of the surplus power and rapid reheating of the hot wa-
ter, adjust the output of the heating system to the output of the photovoltaic
system, e.g. 5 kWp system output => 4.5 kW heating
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