Wearable device for body heat energy harvesting in real-life scenarios

This work focuses on using miniature thermoelectric generators encapsulated in a polydimethylsiloxane matrix for designing a bendable, wearable prototype for self-powering a temperature sensor. Therma-Tech™ compound was chosen as the material to form the heatsink to enhance the device bendability. It was tested in real-life scenarios, in indoor and outdoor environments. When the environmental temperature exceeds 30 °C, the wearable thermoelectric energy harvester was unable to power the temperature sensor consuming approximately 5 µW. However, wearing the device on the lower leg can be an interesting approach to differentiate the execution of dynamic activities from static ones using thermoelectric generators. An automatic segmentation algorithm is presented for detecting transitions between motor activities using data only from the thermoelectric generators. Maximum value of load power generated by the prototype is 27 µW, for a difference of temperature between the thermocouples constituting the thermoelectric generator of 0.23 °C, when the environmental temperature was 20.5 °C. • A wearable, bendable thermal energy harvesting system utilizing miniature TEGs and a polyacrylic heatsink. • The effectiveness of wearable TEGs for harvesting body heat energy reduces as the environmental temperature exceeds 30 °C. • A TEG placed on the human leg can detect physical activity. • A new automatic segmentation method for classifying human motor activities from thermoelectric signals.