Relieving the heating system and heating the service water with ELWA

Supporting the oil boiler with solar energy

A customer from Hoher Westerwald saves expensive heating oil and protects the environment with ELWA.

Datos sobre el proyecto

Construction type:
Construction year and number of square meters:
PV-power and orientation:
Heat storage size:
my-PV product in use:
Referenz Dirk Hartstang

How did you find my-PV?

The owner of the single-family house, built in 1974 in the High Westerwald in Germany, came across my-PV while looking for solar heating options. In regard of the sharp rise in operating costs for all (fossil) energy sources, it was clear for Mr. Hartstrang to take the path towards solar heating with a photovoltaic system.

Obstacles/specialities during the installation

It is important to consider whether the buffer tank – or in this case the boiler – offers a free space for a connection via 1.5 inch thread. If this is the case, the ELWA is ready to go!

Brief explanation of the system – what should be mentioned?

The ELWA could be installed below the combustion chamber on the 420 liter steel boiler with fuel oil for heating and service water. The ELWA uses the direct current (without an inverter and without a grid connection!) directly from the installed photovoltaic modules on the roof. In the case of Mr. Hartstang, the amount of the photovoltaic system, placed on the roof facing southwest or west at an angle of 40°, was 1.66 kWp.

The benefit of the system with the ELWA is that it supports the heating during the cold months and thus enables lower oil consumption. And during the warmer months, when no heating is required, the ELWA replaces the oil heating and still guarantees warm service water.

The ELWA uses solar energy to supply a heating circuit (weather-compensated via a four-way mixer) and the service water via two heat exchangers; the power of the oil boiler is 20 kW. The heat input of the ELWA is monitored by a small power meter from the accessory trade.

Before the ELWA was installed, the heating oil consumption (for heating and hot water) was on average around 1700 liters per year.

Persons in the household and hot water demand?

In the detached house in northern Rhineland-Palatinate, two people permanently live on the 120 m². The number of persons in the household would be relevant for the hot water requirement, but in this case the focus is more on heating support and heating the service water.

Is hot water backup with mains power used?

Mains power is not necessary to ensure the comfort temperature of the heating system, as the oil burner would still be available as a backup.

Opinión personal del cliente y resumen

“The ELWA really is 'simple and brilliant' – very easy to assemble and operate. In the cold season, it relieves my oil burner and in summer it guarantees me warm service water,” enthuses the owner of the single-family house. He expects up to 2,000 kWh yield from the PV modules, which is then converted into hot water for heating purposes. This corresponds to a saving of 200 liters of heating oil per year!

Referenz ELWA Dirk Hartstang - alternative Perspektive
Referenz ELWA Dirk Hartstang Montage
Referenz ELWA Dirk Hartstang Montage 2
Referenz Dirk Hartstang

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