Phase change material -integrated thermoelectric energy harvesting block as an independent power source for sensors in buildings

Abstract

In this paper, an energy-harvesting block is proposed, which consists of a thermo–electric generator (TEG) and phase-change material (PCM). The proposed block generates electricity by utilizing the waste heat accumulated at the exterior wall surface. To maximize the power generation by maintaining the temperature difference be- tween the hot and cold sides of the TEG, the PCM acting as a heat sink or heat source was integrated with the TEG. A prototype of the energy-harvesting block was developed and its generated powers were evaluated under various operation conditions. Experiments were conducted in the laboratory to evaluate the thermal behaviors and power generation performances of the proposed block in three representative days (summer, winter, and extreme representative days). The proposed energy-harvesting block generated average electric powers of 0.01 W in both summer and winter representative days and 0.03 W in the extreme representative day. In each repre- sentative day, the average amount of generated electric energy was approximately 0.1 Wh. Although the electric power harvested by a single block is small, the results suggest that several energy-harvesting blocks connected in series and/or parallel can be used as an independent and semi-permanent power source for nearby sensors and/ or controllers installed in smart buildings.