Photovoltaic heat for holidays at the farm

How did you come to my-PV?

Family Wolfsgruber was looking for a way not to feed excess photovoltaic energy into the grid, but to use it directly for the operation of the farm instead, including residential buildings. “Full feed-in was never the goal,” explains Stefan Wolfsgruber, pointing out the greatest possible self-sufficiency for operating his farm. At the same time, the existing biomass heating should be relieved as much as possible in order to protect the life of the boiler. Precisely these needs can be perfectly met with the solutions from my-PV.

Obstacles/specialities during the installation

A photovoltaic thermal solution does not require any permits. For heating technology, the installation of heating rods in a heat accumulator is a completely normal standard application. Even the linear power modulation by my-PV, with which these electric heaters are finally suitable for photovoltaics, does not change anything. This means that there are no expenses for administrative procedures or permits.

Brief explanation of the system - what should be mentioned?

A 4,000 liter heating tank was already part of the existing wood chip heating system. An ideal storage capacity for my-PV, in order to accommodate surplus PV from the new, high-performance photovoltaic system. The two 9 kW immersion heaters were easy to install as the required 1.5” connection sockets on the buffer were already available.
In addition, an extra electricity meter from my-PV was not even required to detect the surplus at the grid connection point. Thanks to the system openness of our company for control by third-party providers, the measurement signal from the inverter manufacturer could be used. Thus, family Wolfsgruber saved another essential component and there was no additional space requirement in the house junction box.

Persons in the household – hot water needs etc.?

Stephan and Nina Wolfsgruber live at the farm together with their three children and Stephan's parents. In addition, there is a heat requirement for hot water and heating for five holiday apartments and two further residential units, which are connected to the buffer storage tank via a small local heating network. Overall, the heat requirement is immense. Unfortunately, even with a 40 kWp PV system and an 18 kW heating solution from my-PV, it is not possible to switch off the heating in summer, as it could easily be done in a one- or two-family house, for example. The benefit at the Attwengerhof in Traunkirchen lies in the relief and protection of the wood chip boiler, as well as in increased self-sufficiency and higher self-consumption.

Is a hot water backup with mains power used?

The biomass heating is in operation all year round. During the summer months, however, the boiler is only fired up in the late afternoon to give the system the opportunity to load the storage tank with photovoltaic heat during the day and not to block any storage reserves.