Heat generation from PV surplus in the Lavant Valley

The PV system with 11.25 kWp on the roof generates significantly more electricity than the household consumes – even with a battery storage unit in place. This creates ideal conditions for using surplus solar power for heat. Instead of feeding the surplus energy unprofitably into the public grid, the homeowner relies on the AC•THOR, the photovoltaic power manager from my-PV.

After replacing an old oil heating system with a modern pellet boiler, the integration of the AC•THOR followed – based on a recommendation from the crafts business Enerix Solar. The installation was carried out by the technically skilled homeowner himself, supported by my-PV’s customer service, which he describes as “excellent.”

What makes this setup particularly special is the use of operating mode M2: the AC•THOR controls two heating elements in sequence and with continuous modulation – one in a 500-liter buffer tank, the other in a 300-liter domestic hot water tank. As a result, hot water for the five residents is generated almost entirely from PV surplus. During the winter months, the AC•THOR also supports the pellet heating system.

The outcome: In the first year alone, approximately 2,100 kWh of surplus solar power was successfully converted into heat – cost-effective, sustainable, and CO₂-saving. Without the PV solution, the heat would have been supplied by the pellet heating system. However, the cost savings clearly convinced the owner of the advantages of solar-powered heating.

A detailed explanation of how operating mode M2 works, along with all technical components used in the system, can be found in the full reference project description.