ETH Engineer Makes Solar Heat Affordable for Factories

Factories need heat more than they need electricity, and right now they're burning natural gas to get it.

ETH Zürich engineer Luca Thommen just built a solar thermal collector that could change that. His prototype, sitting quietly on an ETH rooftop, converts sunlight into industrial-grade heat at a fraction of the cost of previous systems.

The breakthrough isn't fancy technology. It's smart simplicity.

While most people focus on solar panels generating electricity, Thommen tackled a bigger climate puzzle: how factories heat their processes. Pasteurizing milk, dyeing fabric, sterilizing medical equipment, distilling chemicals. All these require temperatures up to 150°C, and all currently rely on fossil fuels because renewable options have been too expensive.

Thommen's collector uses reflective surfaces to concentrate sunlight onto an absorber panel, which transfers heat to air or water. The secret is in what he left out: his design uses minimal metal and relies on lightweight, inexpensive insulation materials. No complex engineering. No costly components.

"The technology already exists in principle, but it is not yet cost-effective," Thommen explains. His goal is simple: same performance, significantly lower cost.

The approach came from an unlikely journey. Thommen started as a traditional mechanical engineer studying combustion engines and robotics. Then the climate crisis prompted a question: how could his skills actually help? His master's thesis under Professor Aldo Steinfeld became the answer.

When the first prototype hit target temperatures, Thommen knew he had something real. Companies noticed too.

The Ripple Effect

Climeworks, the ETH spin-off that pulls CO₂ from the atmosphere, already needs heat around 100°C for its processes. That's exactly what Thommen's collector delivers. Food manufacturers, pharmaceutical companies, and chemical plants are all potential customers, representing a massive slice of industrial energy use.

The timing couldn't be better. As electricity grids shift to renewables, industrial heat remains stubbornly dependent on natural gas. That makes it one of the toughest nuts to crack in the energy transition.

Thommen's Pioneer Fellowship grant of up to 180,000 Swiss francs gives him 12 to 18 months to develop a market-ready product. He's already in talks with potential customers and investors, planning pilot facility tests within the year.

The engineer isn't focused on building a startup empire. "It is important that the technology is actually used and that it makes a difference out there," he says.

His straightforward solar collector could help companies slash CO₂ emissions while dodging volatile energy prices. For factories worldwide, affordable solar heat might finally make ditching fossil fuels not just possible, but profitable.