Modeling and optimization of radiative cooling based thermoelectric generators

TL;DR

This paper presents an optimization framework for radiative cooling-based thermoelectric generators, enhancing their power output by optimizing geometry and operating conditions for night-time passive power generation.

Contribution

It introduces a combined thermal and electrical model to determine optimal operating conditions and provides design guidelines for maximizing RC-TE device performance.

Findings

Optimal operating conditions increase power output.

Maximum power density depends on area ratio of cooler to thermoelectric elements.

Parametric study identifies key factors for performance enhancement.

Abstract

The possibility of night-time power generation has recently stimulated interest in using the radiative sky cooling mechanism with thermoelectric generators (TEG). These passive, low-temperature difference devices have been shown to generate electricity at night with no active input of heat needed, instead using the ambient air itself as the heat source. Here, we optimize both the geometry and operating conditions of radiative cooling driven thermoelectric (RC-TE) generators. We determine the optimal operating conditions, including maximum power point and maximum efficiency point, by developing a combined thermal and electrical model. Our results show that the optimal operating condition results in larger power output than was previously expected. Moreover, we show that maximum power density occurs when the area ratio between cooler and P or N element reaches an optimal value. Finally, we perform a parametric study that takes account of environmental and structural parameters to improve the performance of the RC-TE device, including enhancing heat transfer between the hot surface and ambient air, suppressing the cooling loss of the radiative cooler, and optimizing the geometry of individual thermocouples. Our work identifies how to maximize the output of RC-TE devices and provides comprehensive guidance on making use of this new passive power generation method.