Performance evaluation and parametric analysis of nighttime electricity generation system integrating thermogalvanic cells with radiative sky cooling

Abstract

While distributed power generation has been made possible by photovoltaic cells during the day, there is no comparable option available at night, especially in off-grid areas around the world. In our work, a cost-effective nighttime electricity generation approach based on thermogalvanic cells and radiative sky cooling is proposed. Based on the developed thermal and electrical coupled model, we determine the maximum power point and optimal operating conditions, including the optimal load ratio of 1.2 and area ratio of 1. The calculated results show that, with systematic optimization, a high power density of 900 mW/m2 is achievable for the device by enhancing (suppressing) heat transfer between the hot (cold) side and ambient air, operating at hot and dry conditions, and optimizing the geometry of individual cells. Furthermore, the presented device significantly outperforms the nighttime thermoelectric generator and could directly power various electric devices to meet the power needs of people in remote or off-grid regions. This work identifies how to achieve maximal electrical power generation for nighttime radiative-cooling-assisted thermogalvanic devices, providing a feasible approach for constructing high-performance nighttime electricity generation devices.