AC ELWA 2 in Belgium
Belgium relies on AC ELWA 2 and HomeWizard
In Mechelen, a homeowner uses HomeWizard and my-PV to heat water with surplus solar power.
Facts about the project
- Owner
- Location
- Photovoltaic output and orientation
- Inverter
- battery storage
- Heat storage size
- Building type
- Year of construction and square meters
- my-PV product
- System control
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In Flanders, feeding solar power into the grid is hardly worthwhile anymore: PV system owners receive only €0.02 per kWh as compensation. In the near future, feeding into the grid might even become subject to charges – a development that PV operators in the Netherlands are already experiencing.
For this reason, Belgian homeowner Ivo B. looked for an efficient way to increase his self-consumption and minimize grid feed-in as much as possible in the future. His goal was a win-win solution: using excess solar power for heating instead of feeding it into the grid, while at the same time reducing the operating hours of his heat pump. The reduced load extends the heat pump’s lifespan – another clear advantage.
Heat pumps cannot be continuously adjusted to fluctuating PV surpluses. To ensure that not a single watt of excess solar energy goes unused, Ivo B. needed a continuously regulated solution. During his research, he came across the AC ELWA 2, a continuously regulated PV immersion heater for grid-connected PV systems. The solution from my-PV uses every surplus watt for domestic hot water production, ensuring that no excess is fed into the grid.
Personal customer opinion and resumee
“I am very satisfied with the AC ELWA 2. The system works seamlessly with the HomeWizard P1 dongle and the Victron EMS, bringing me one decisive step closer to an energy-independent home – all with a manageable investment.”
Compatibility between my-PV and HomeWizard
Since the resourceful Belgian was already using the HomeWizard P1 Meter, which reads the digital meter and provides insights into grid consumption and feed-in, integrating the AC ELWA 2 into the existing system was particularly easy. Thanks to the compatibility between HomeWizard and my-PV, no additional surplus detector was required, which simplified the integration of the AC ELWA 2 into the existing setup and naturally minimized acquisition costs.
The retrofit was straightforward: after activating the API in the HomeWizard app and configuring the IP address of the HomeWizard P1 Meter via the AC ELWA 2, the system was ready for operation.
How is the system set up?
The house is a detached single-family home in Mechelen, Belgium, built in 1995 and extensively renovated between 2011 and 2024. The 139 m² living space is home to two people, with a daily hot water demand of 50 to 70 liters.
The PV system has a capacity of 5.6 kWp and is connected to a Fronius Primo 5.0 kVA inverter. The modules are south-facing with a tilt angle of 35°. The solar power generated is first consumed directly by household appliances. Surpluses are stored in a 15.36 kWh BYD battery storage system and – if available – used for charging an electric vehicle via a 32 A Alfen Single Pro Line wallbox. Any remaining surplus is now used by the AC ELWA 2 for water heating – continuously regulated, of course, for maximum yield.
The domestic hot water system consists of a 300-liter storage tank, divided into two 150-liter sections. The upper tank is connected to the air-to-water heat pump, which typically heats the water to 50 °C between March and October. The lower tank is connected to a soapstone stove and provides hot water at 45 °C between November and February. The AC ELWA 2 complements the system by heating the upper tank up to 90 °C with PV surplus. In winter, it also ensures hygienic operation by automatically heating the water to 60 °C every 14 days to prevent legionella.
This project is a prime example of step-by-step PV surplus utilization: solar power is first consumed in the household, then stored in the battery, then used for charging the electric car, and finally used for domestic hot water production with the AC ELWA 2. The result is a highly efficient system that maximizes self-consumption, reduces grid feed-in, and simultaneously extends the service life of the heat pump.
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AC ELWA 2
To maximize the self-consumption of your current PV system, AC ELWA 2 harnesses the system's surplus photovoltaic energy to heat your water. Increasing self-sufficiency simultaneously safeguards against unpredictable or rising operating costs.
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