PVT and geothermal energy combined in the new Herrsching secondary school building
A pioneering energy concept that combines photovoltaic thermal energy (PVT) with geothermal energy was implemented for the new secondary school in Herrsching am Ammersee. The aim was to realise a high proportion of renewable energy - despite limited space and water regulations.
Project: New high school Herrsching am Ammersee
228 PRISMA® PVT RBX Modules à 450 W
56 Geothermal probes à 90 m depth
Heat pump: 290 kW
Gas boiler: 290 kW (80/60 °C)
Electrical power PVT system: approx. 103 kWp
Assembly: CW 8 / 2026
Hybrid solution comprising PVT, geothermal energy and heat pump for a large-scale municipal project
Reduction of the geothermal probe field through PVT
The original plans envisaged a geothermal probe field with 75 probes. However, this design could not be realised due to limited space and water law requirements.
The solution was to add a PVT system as a second renewable energy source. Through the use of 228 PRISMA® PVT RBX modules, the geothermal probe field could be 56 probes reduced a reduction of around 25 %. At the same time, the system supplies around 103 kWp a relevant contribution to the power supply for school operations.
Efficient combination of heat and power generation
The hybrid collectors used generate usable heat as well as electricity. The waste heat from the PV modules is absorbed via a roll-bond absorber and utilised as source energy for the brine heat pump.
At the same time, the cooling of the PV modules leads to an improved electricity yield. The result is a system that efficiently combines thermal and electrical energy generation and increases the overall output of the system.
Hybrid energy concept
The energy supply is based on the interaction of several components: The 290 kW heat pump covers around 70 % of the heating output, while a 290 kW gas boiler takes care of peak loads and hot water heating (up to 80 °C).
The energy generated is fed into the heating circuits via defined transfer and distribution points. This combination creates a hybrid supply system with high operational reliability and flexibility.
Regeneration and long-term system stability
Outside the heating period, the heat generated by the PVT system is used to regenerate the geothermal probe field. At the same time, the building is cooled via the borehole array. During the heating season, the PVT modules together with the geothermal probes serve as an energy source for the heat pump and thus contribute to the building's regenerative heat supply. In this way, the PVT system fulfils different functions within the overall system over the course of the year.
All images shown on this page with the kind permission of
Taranis Energie GmbH.
