A Novel High-temperature Aircraft-specific Energy Harvester Using PCMs and State of the art TEGs

Abstract

Energy self-sufficiency is a key enabling factor in realizing any truly autonomous and completely wireless system. With regard to aeronautical applications, creating autonomous wireless sensor nodes can potentially help to drive the maintenance costs for civil aviation companies down, by converting some of the regular maintenance checks to an on demand basis. Thermoelectric energy harvesting can be used in environments where temperature differences occur naturally or are a byproduct of a process, preferentially in areas difficult to reach. By using phase change materials (PCMs) attached to one side of a thermoelectric generator (TEG), the temperature difference across the device can be temporarily enhanced, leading to increased electrical energy production. Thermoelectric energy harvesting using PCMs has been previously explored as an electrical energy source, in sub-freezing temperature environments and its potential has been evaluated most recently both theoretically and experimentally, but most importantly proven over a six month flight test campaign. Furthermore, the performance of tailored TEGs in combination with different PCMs has been studied up to temperatures of 190°C. In order to expand on previous results, state of the art TEG sets made by Micropelt were installed on two identical aluminium containers. The containers were redesigned to include a mounting ring for easier aircraft installation. Simulations as well as experiments in a climate chamber and on a hot plate were performed. With the latter approach the heating rates typically found near the pylon area are mimicked whereas the first is used to assess different potential ambient conditions in general. In addition, previously used erythritol is compared to H120 offered by PCM-Products Ltd., allowing to investigate and to evaluate the effect different PCMs have on the energy output.