Researchers Unveil Hybrid Solar and Radiative Cooling System to Power and Cool Data Centers

Researchers at the Karlsruhe Institute of Technology (KIT) have engineered a hybrid energy surface capable of concurrently generating electrical power, high-temperature heat, and sub-ambient cooling from a single installation area, as first reported by TechXplore. The design combines photovoltaic and solar-thermal collectors with passive daytime radiative cooling (PDRC) to optimize space usage on commercial roofs and industrial building envelopes.

The research, detailed in a study published in the journal Cell Reports Physical Science, was led by Dr. Gan Huang of KIT's Institute of Microstructure Technology in collaboration with Stanford University Professor Shanhui Fan. According to Huang, the multi-output surface concept is designed to address facility deployment constraints while offering a potential thermal management and power solution for energy-dense infrastructure, including artificial intelligence data centers.

The core of the tri-generation system relies on a multi-layer optical design that resolves the physical opposition between high-temperature thermal absorption and passive cooling. The top layer features a transparent emitter fabricated from a silica substrate layered with polydimethylsiloxane, a silicone polymer. This top surface allows visible solar rays to pass through while emitting heat as infrared light outward through the atmospheric window toward space.

Directly beneath the transparent cooling film, a Fresnel lens concentrates the incoming sunlight onto a smaller photovoltaic-thermal collector located underneath. Study lead author Iván Alberto Cruz García noted that using a optical concentrator keeps the heat-generating solar collection area physically segregated from the top radiative cooling film, preventing thermal crossover between the cooling and heating elements.

In field testing under real-world outdoor conditions, prototype units produced cooling temperatures up to 6.5 degrees Celsius below the ambient air temperature. Concurrently, the integrated solar collection module yielded an electrical power output density of 60.6 watts per square meter alongside thermal heating outputs reaching up to 110.8 degrees Celsius (231 degrees Fahrenheit).

The project expands upon the research group's earlier development in 2024, which produced a transparent material intended for passive building cooling and natural daylighting. By embedding energy harvesting capabilities into that clear optical substrate, the engineering team converted the passive thermal film into an active power system.

Moving forward, the researchers plan to refine the design's solar cell efficiency, optical transmission performance, and internal thermal isolation mechanisms to prepare the technology for broader commercial evaluation.