Solar-charged rock bed powers coffee roaster with stored heat

Researchers at Sandia National Laboratories have developed an innovative solar thermal energy storage system that could revolutionize how coffee roasters operate. The technology utilizes photovoltaic panels to capture solar energy, which is then electrothermally converted and stored in a radial packed-bed system filled with rocks. This stored heat can reach temperatures as high as 600°C (1,100°F) and can be released on demand to power existing natural gas-fueled roasters.

The project, a collaboration with Michael Sweeney of Michael Thomas Coffee, aims to provide a bolt-on solution for businesses to transition to solar energy without needing to replace their current equipment. The system is designed for storage durations that can last for several days, allowing for consistent operation even when solar availability is limited. This indirect solar heating approach allows roasters to adapt to a new energy source while maintaining familiarity with their existing machinery.

During recent tests at the National Solar Thermal Test Facility, the system demonstrated its effectiveness by roasting coffee beans for light, medium, and dark roasts. Notably, the solar-powered roaster reduced roasting times by a few minutes for dark roasts and led to more uniform roasts compared to traditional gas-fired methods. The ability to preheat and cool the roaster more quickly also translates to higher throughput and increased batch production.

Beyond coffee roasting, the technology shows promise for other industrial applications, particularly within the food and beverage industry. Sandia aims to patent the system and partner with companies to commercialize the technology, potentially leading to significant cost savings and improved efficiency for businesses. The project highlights Sandia's commitment to leveraging natural resources for community benefit and driving business innovation.