The Hartkop solar coffee roaster weighs in a whopping 5.5 tons including heavy supports to stabilize it in 90 mph winds in Colorado. Plus, it has solar-powered fans to cool the beans after roasting. So, while it’s not for home use now, maybe the technology involved will find its way to smaller home versions.
That would be as absolutely retarded as a hoping for a home version of a windmill to power your coffee grinder.