We are fascinated by energy-harvesting technologies. When we read or hear about new continuous-monitoring biometric sensing wearables and medical implants, one of the first questions that come to mind is, “OK, but what’s the power source?” Frequent battery replacement is a pain with wearables and a non-starter for implanted devices. Recharging batteries in wearables, whether wired or wireless, is only a small step better than using replacements. Alfred Poor wrote about the necessity of energy harvesting for wearables in 2015. Last summer I wrote about work on energy harvesting from the human knee by engineers from the Chinese University of Hong Kong.

Scientists at the Electronics and Telecommunications Research Institute (ETRI) in South Korea recently released news of their work developing a thermoelectric module that generates minute amounts of energy from human body heat. I live in the southern U.S. and therefore I’m familiar with heat pumps. Our HVAC systems use heat pumps that transfer heated air into our dwellings in the winter and out of our homes in the summer. The ETRI module concept is similar to the heat pump, but in this case, it’s a heat sink.

The biomimetic heat sink depends on a temperature difference between the structure and human skin. It converts body heat to electrical energy. According to ETRI, they have been able to increase the thermoelectric output of their device by five times and generate up to 1.5 times as much electrical power as much as other researchers.

The ETRI researchers are now further developing the technology’s power management, focused on reducing the number of components to a single chip to improve wearability. ETRI plans include commercialization within the next two to three years.