I'd be careful calling it a refrigerator. It's a box that is well insulated.
Basically it's just an old fashioned icebox without the benefits of actual ice. He also talks about his other "invention" which is a water filter made from clay. Clay water filters have been available in India for a long long time. I recall seeing them 30 years ago. I suspect that they might be effective for some larger parasites but certainly not something I'd want to entrust my health to.