"Sunmaxx" in Ottendorf-Okrilla has started production of innovative solar modules

Founded just two years ago, the company "Sunmaxx PVT" in Ottendorf-Okrilla now wants to conquer the world market with innovative solar modules. What is special about the technology?
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Man sieht den Geschäftsführer Wilhelm Stein von Sunmaxx
Sunmaxx has started production of photovoltaic thermal modules (PVT) in Ottendorf-Okrilla. Managing Director Wilhelm Stein still has big plans. Marion Doering

By Siri Rokosch

Ottendorf-Okrilla. The company "Sunmaxx" officially opened its first production facility for innovative solar modules in Ottendorf-Okrilla on Monday. The so-called PVT solar modules are used to produce both electricity and heat.

The new technology works with "thermal management" from the automotive sector, says "Sunmaxx" Managing Director Wilhelm Stein. "Ten to sometimes 15 engineers have developed this new technology. This gives us a head start of several years and makes us one of the largest PVT production facilities in the whole of Europe."

"Sunmaxx" has big plans in Ottendorf

Production has been taking place in Ottendorf-Okrilla on Schutterwälder Straße since the end of 2023. Between 100 and 1,000 modules are currently produced per week. The aim is to produce 500 per day in the future, says Stein. That would be 120,000 per year.

The number of employees is also set to increase significantly, from 25 at present to between 60 and 80 by the end of the year - with the prospect of as many as 1,000 employees being envisaged. "But then we would no longer be able to stay in Ottendorf, that would exceed our capacity," explains the Managing Director.

The company, which has only been on the market for two years, has a production area of around 4,000 square meters at Schutterwälder Straße 13. There, photovoltaic modules are provided with an aluminum backing, which is otherwise not common in solar technology: they are flat heat exchangers filled with water and glycol. Stein, who holds a doctorate in physics, refers to this as a "homogeneously flowing hollow surface". In layman's terms, he also likes to call the supplied part from the automotive industry a cooling plate.

How do the new solar modules work?

The PVT modules from "Sunmaxx" offer a powerful symbiosis of electricity and heat generation. Installed on the roof, they contribute to both the electricity and heat supply. This can create a virtually self-sufficient energy system at home as well as "in the entire energy sector - from trade and industry - to modern district heating systems in entire urban areas," explains Stein.

In principle, there are currently two different ways of using solar energy: photovoltaic modules, which convert solar energy into electricity, and solar collectors, which generate heat from the sun's rays. "However, PVT modules can now do both, and in a single product," says Stein, who has been in the solar business for 20 years. "By generating electricity and heat at the same time, the solar energy shining onto a roof can be used with maximum efficiency. This makes optimum use of the available space. In combination with heat pumps, PVT modules work very effectively and supply heat and electricity almost self-sufficiently and 100 percent climate-neutrally."

Particularly efficient and highly developed systems from the automotive industry are used for the thermal management of the modules. In contrast to normal photovoltaic modules, the PVT systems have a built-in "air conditioning system". The heat exchanger on the back of a module would extract heat and transfer it to a heating circuit. At the same time, however, the cooling of the solar cells also further increases the electricity yield.

"Sunmaxx" is the only manufacturer in the world that can offer this innovative combination. "This is our competitive advantage with which we will revolutionize the electricity and heating market - climate-friendly, sustainable and without greenwashing," says Wilhelm Stein. The company developed this technology together with the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg and the company Mahle from Stuttgart, among others.

The maximum output of a PVT module is around 1,600 watts, of which 410 watts is electrical and 1,200 watts is thermal. A module consists of different layers - the frame, glass, EVA film, solar cells, another layer of EVA film and a back sheet as well as an aluminum heat exchanger.

How customers could benefit from PVT technology

Because the "Sunmaxx" PVT technology is regarded as the "optimal source for the heat pump", it is fully eligible for state subsidies, Stein explains one of the advantages for customers. The new technology is suitable for the roof of a single-family home as well as for industry and heat suppliers, as sustainability goals can be achieved more easily with a climate-neutral and cost-efficient energy supply. The PVT modules could also be used to cool buildings.

However, these modules cannot be purchased directly in Ottendorf-Okrilla. Instead, the company works with specialist partners and installers, where customers can have the new technology explained to them and also purchase the modules. In terms of price, they would be in the upper range compared to normal PV systems. Stein would not give exact prices, but emphasizes that the expansion of production would also reduce costs for customers.

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