Annual energy harvesting performance of a phase change material-integrated thermoelectric power generation block in building walls

Abstract

Herein, we discuss the design and evaluation of a passive electricity generator, which we call an energy-harvesting block. The energy-harvesting block is a thermoelectric generator-based passive energy-harvesting system integrated with a phase change material that is designed to harvest energy from waste heat on the exterior walls of buildings. The thermoelectric generator in the energy-harvesting block converts heat into electricity based on the Seebeck effect. A phase change material was used to cool the cold side of the thermoelectric generator by acting as a heat sink to convert sensible heat into latent heat. Experiments were conducted under the conditions of monthly representative wall-temperature profiles. Voltage and temperature data were collected to measure the phase change and electricity generation. Based on these experiments, this study predicted the electricity annually generated by the energy-harvesting block. The results showed that 2.1 kWh/m(2) of electricity was generated in a year. Average generation power was 0.03 W, and average voltage was 0.3 V. It was shown that 3-4 energy-harvesting blocks could supply enough electricity for modern digital circuits such as the ones used in sensors and controllers.