Using a Rock Bed Charged by Solar Energy to Power a Coffee Roaster – CoffeeTalk

Michael Sweeney is utilizing solar energy to roast coffee beans at the National Solar Thermal Test Facility, collaborating with Sandia National Laboratories. This initiative employs a technology developed by Sandia that captures energy from photovoltaic panels, which is then stored in a bed of rocks, enabling the roaster to achieve temperatures up to 600°C (1,100°F). The system operates on an indirect solar heating method, with energy being electrothermally charged and subsequently released into a drum to facilitate coffee roasting.

The project is designed to provide a retrofit solution for existing natural gas roasters, allowing them to adopt solar-thermal energy, with storage capabilities lasting several days. Sweeney highlights the advantages of adapting current roasting equipment, stating that Albuquerque’s abundant sunshine offers a new perspective on the roasting craft. He emphasizes that this system goes beyond simple cost savings compared to new electric roasters, aiming to enhance efficiency, quality, and productivity in traditional roasting operations.

During experimental testing, varying levels of coffee roasts demonstrated reduced roasting times, with solar energy yielding more uniform results compared to traditional gas methods. This efficiency was echoed in a prior experiment involving green chile roasting, where the time was significantly halved. The rapid preheating and cooling capabilities of the solar roaster also allow for increased throughput, facilitating more batches within the same timeframe.

Sweeney, alongside his family, underscores that the essence of great coffee lies in its complexity, careful sourcing of high-quality beans (sourced from women farmers in Guatemala), and a commitment to improvement. Their collaboration with Sandia stems from shared values of consistency, community, and quality, expanding their connection to the broader coffee industry.

Looking ahead, Sandia National Laboratories envisions broader applications for the solar heating technology and aims to secure patents for marketplace innovations. Bob Sleeper, from Sandia, focuses on commercializing the heating and energy storage system, partnering with local food processing enterprises and entrepreneurial initiatives like the Department of Energy’s Boost Program. This initiative illustrates Sandia’s commitment to leveraging New Mexico’s resources to foster community benefits and business innovation, with potential applications extending to grain and chocolate roasting as well.

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