Solar and thermal energy harvesting with a wearable jacket

This paper presents the design of a wearable energy harvesting jacket, which harvests energy from solar and body heat in the outdoor environment. The energy harvesting system consists of 16 photovoltaic (PV) cells, 12 thermoelectric generators (TEGs), and five power management chips, and it charges two AAA NiMH batteries in series. The 16 PV cells are partitioned into four zones (chest, back, right and left shoulders), where PV cells in the same zone are roughly subject to the same irradiation level. All the PV cells in the same zone are controlled to operate at nearly the same maximum power point. Six TEGs are connected in series to increase the output voltage, and two sets of those six TEGs are controlled by the same power management circuit. The average power harvested by the solar system ranges between 475 mW to 500 mW on a sunny day. The power generated by TEGs lies in μW range due to the low temperature gradient available within the jacket. The prototype illustrates the proposed solar energy harvesting system with partition of cells into different zones is simple, yet effective.