Performance analysis of the sky radiative and thermoelectric hybrid cooling system

Abstract

In this paper, the radiative sky cooler (RSC) and thermoelectric cooler (TEC) are integrated to form the RSC-TEC hybrid cooling system that can reduce the TEC required power consumption and increase the system’s cooling capacity over a standalone RSC. Specifically, a feasibility study is conducted to evaluate the design and working conditions that allow this system to have superior performance; For example, the TEC module type and number, RSC surface area and radiative emissivity value, solar absorption coefficient and air convective heat transfer coefficient have been parametrically swept to assess their effects on the system’s cooling capacity and the TEC power saving coefficient, a metric to define the degree of TEC power consumption reduction due to the RSC. The analyzes have been conducted through a non-dimensional steady-state mathematical model of the hybrid system that cools an enclosed space. Results demonstrate that a 0.1 m2 RSC could reduce the required power consumption of a TEC module (size 4 cm by 4 cm) by up to 10%. Moreover, increasing the RSC surface area further improved the TEC power saving coefficient, but the solar absorption coefficient had to be under 0.02 to maintain a reasonable TEC power saving coefficient.