- Innovative hybrid concept in Berlin metropolitan area: A residential com-plex combines Sunmaxx PVT modules with a GeoCollect geothermal sys-tem and an existing gas heating in a cost-effective and gradually imple-mentable decarbonization strategy.
- Highly efficient energy supply through sector coupling: An 80 m² PVT sys-tem generates both electricity and heat at the same time, while excess summer heat is stored underground and utilized during winter for effi-cient heat pump operation.
- Practical example of the heating transition: The project demonstrates how hybrid heating systems can reduce operating costs, meet sustaina-bility requirements, and ensure security of supply.
Dresden/Berlin, 18 June 2026: A residential complex in the greater Berlin area is relying on an innovative integrated energy concept that combines photovoltaic-thermal hybrid modules with geothermal energy. The project serves as a practical example of how an economically viable hybrid approach can support the gradual decarbonization of the building sector. Starting from a conventional gas heating system, renewable energy sources have been intelligently integrated into the existing infrastructure. While PVT modules manufactured by Sunmaxx generate both electricity and heat, geothermal collectors from Chemnitz-based GeoCollect provide renewable ground-source energy. This approach reduces the load on the existing gas boiler, lowers operating costs, and helps ensure compliance with current sustainability requirements.
The combination of PVT technology and the GeoCollect system enables highly efficient and reliable operation of renewable heat sources. Excess thermal energy generated by the PVT modules – particularly during the summer months – is transferred into the ground via a brine circuit and stored there. During winter, this stored energy is recovered to support highly efficient heat pump operation.
To achieve this, an approximately 80-square-meter PVT array equipped with Sunmaxx PX-1 modules was installed. The project’s lead designer, Prof. Dr.-Ing. Daniel John of WP engineering, explains: “This project demonstrates that the heating transition does not necessarily require radical, all-at-once system replacements. Hybrid energy concepts provide an economically sensible and sustainable entry point into decarbonization – whether in residential buildings, larger district developments, or even commercial and industrial applications.”
Ralf Janssen, Managing Director of Consulting Janssen GmbH, which was responsible for implementing the project, adds: “What makes this project particularly interesting is the clever integration of different energy sources – both conventional and renewable. By combining them, a robust and future-proof energy supply concept emerges. Hybrid approaches like this represent a pragmatic compromise that helps reduce concerns associated with the transition to renewable energy systems. Thanks to their scalability, they can make a significant contribution to the heating transition.”
GeoCollect GmbH also views the project as an important step toward integrated energy systems based on sector coupling. Dr. rer. nat. Lucie Novakova, Ph.D., of GeoCollect comments: “The combination of geothermal energy and PVT technology opens up new possibilities for efficient and economically attractive heat supply solutions. Particularly in district-scale developments, this creates enormous potential for the long-term reduction of fossil fuel consumption.”
For Sunmaxx, practical feasibility is a key consideration. The company will showcase regenerative heat supply solutions based on PVT technology at Intersolar Europe 2026 (June 23–25, 2026, Munich) at booth A1.554. Michael Gehenzig, Head of Sales at Sunmaxx, says: “Germany’s economic situation remains challenging. Homeowners and businesses alike recognize the need for energy-efficient modernization, yet many are currently hesitant to invest. What the market needs right now are realistic solutions that successfully balance economic viability, energy security, and sustainability. This project demonstrates that such a balanced approach can work very effectively.”
Hybrid energy supply concepts are playing an increasingly important role on the path toward affordable and climate-friendly energy systems, particularly in situations where a complete transition to fully renewable solutions is not yet technically or economically feasible. By intelligently combining different technologies, flexible solutions can be created that deliver meaningful CO₂ reductions today while also providing long-term investment security.
Article image: Section of the PVT system supplying a hybrid heating installation in the greater Berlin area / © Consulting Janssen GmbH
About Sunmaxx
Sunmaxx PVT GmbH is a leading manufacturer of photovoltaic-thermal (PVT) systems and the world’s first company to produce hybrid modules in industrial-scale serial manufacturing. PVT modules combine photovoltaics and solar thermal technology within a single system, delivering both electricity and heat for brine-to-water heat pumps in an efficient, space-saving, and cost-effective manner. With this technology, Sunmaxx is advancing the heating transition and enabling the decarbonization of buildings of all sizes – from single-family homes to municipal heating networks.
About WP engineering
WP engineering GmbH is an engineering consultancy based in Chemnitz specializing in renewable energy systems, with a focus on heat pumps, PVT installations, and sustainable building energy design. The company develops customized solutions for efficient and future-proof heating and cooling systems, covering the entire process from concept development to implementation.
About Consulting Janssen
Based in Lower Saxony, Consulting Janssen GmbH has been operating internationally for more than 15 years as a service provider specializing in energy-efficient building refurbishment and geothermal systems. The company plans and implements projects utilizing both air-source and geothermal energy and is responsible for, among other projects, Europe’s largest ground collector installation in Berlin. Consulting Janssen is an experienced partner in integrating PVT systems into comprehensive geothermal energy concepts.
About GeoCollect
GeoCollect GmbH, headquartered in Chemnitz, manufactures geothermal collectors and supports architects, planners, investors, and HVAC professionals in the design and implementation of geothermal systems. Thanks to their innovative design, GeoCollect’s high-performance collectors maximize heat extraction from the ground. Since its founding, the company has completed more than 5,000 projects in Germany alone, contributing to annual CO₂ savings of approximately 10,000 tonnes.