The Efficiency of Waste Heat Recovery

Energy recovery is moving from a theoretical advantage to a structural reality. Researchers at the Korea Institute of Energy Research (KIER) have developed a shingled photovoltaic module designed to integrate with thermoelectric generators (TEGs), enabling the recovery of waste heat from PV systems as reported by pv magazine.

The core problem with TEGs has been cost and performance. While these devices use the Seebeck effect to convert temperature differences into electricity, their adoption has remained limited. The KIER approach addresses this by using shingled cell technology to replace conventional ribbon-based interconnections. By connecting solar cell strips directly in series, the researchers eliminated soldered ribbons, which increases the active area for light absorption and reduces thermal and mechanical stresses.

This architecture is specifically beneficial for TEG integration. The series-connected strip design increases operating voltage while reducing output current.

The fabrication process utilized PERC solar cells from Shinsung Engineering. The researchers used a 1,064 nm infrared laser scribing process and mechanical cleaving to create the strips. The study produced several module configurations:

• Modules with three, five, or seven strips achieved a total active area of 100 cm².
• A 14-strip configuration increased the active area to 170 cm².

The dimensions of these strips varied by configuration, including 100 × 38.83 mm, 100 × 21.70 mm, 100 × 16.07 mm, and 85 × 16.07 mm. To bond these strips, the team used CA 3556HF conductive adhesive, which was hot-pressed and cured at 180 C for 1 minute. The final modules were encapsulated with glass, EVA, and a PET backsheet to ensure environmental stability.

The significance here lies in the structural optimization of the module itself. By redesigning how cells connect, the researchers are not just improving solar efficiency, but creating a platform for secondary energy harvesting. If the cost barriers of TEGs can be lowered, this architecture provides the necessary framework to capture energy that is currently lost to the atmosphere.

The question for the industry is whether this shingled approach can scale beyond laboratory strip dimensions to meet the demands of industrial-scale heat recovery.

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