I wrote:
Scale. The device should produce at least 100 Watts of heat or 10 Watts of thermoelectric power.
By the way, many fringe inventors have the impression that a device must produce thousands of Watts before it is practical. This is incorrect. There are many commercial uses for a 10 to 100 Watt device. Even a 10 W heater would be useful for some niche applications, such as keeping equipment warm in the Arctic.
- Jed
