Impact of environmental factors on night-time electricity generation using thermoelectric generator

Nighttime electricity generation (NTEG) using thermoelectric generators (TEGs) and radiative cooling concept is a widely known phenomenon. However, the NTEGs are challenged by low voltage generation. The factors influencing the performance of the NTEGs comprise environmental conditions, such as ambient temperature, wind velocity and relative humidity. However, the effect of these parameters has not been explored. Therefore, the present study aims to experimentally investigate the influence of these variables on the generated power resulting from the temperature difference created between different entities of the NTEG setup by using an inhouse designed facility. The experimental setup consisted of multiple TEGs sandwiched between a radiative plate at the top and an aluminium block attached to a hot plate at the bottom. The tests were performed on various nights to analyse the effect of these parameters. The night with a higher ambient temperature triggered higher temperature difference between the top and bottom surface of the TEGs, resulting in the higher voltage production. Moreover, the same trend was observed for the wind velocity. By contrast, the largest temperature gap between an emitter plate and the surrounding air was recorded on a night with the lowest relative humidity, thereby providing a higher voltage. Furthermore, with various series, parallel and series-parallel configurations, we finally found a combination of commercially available TEGs for NTEG, which can be effectively used for lighting up a three-watt bulb.