Polymeric coatings for passive radiative cooling of PV modules in hot and humid weather: Design, optimization, and performance evaluation

Abstract

This article evaluates the utilization of Polyethylene terephthalate (PET) and Polydimethylsiloxane (PDMS) polymeric coatings for passive radiative cooling of commercial photovoltaic (PV) modules. The methodology involves the design of film coatings and the analysis of their optical properties. A numerical model is developed to simulate the thermal behavior of the PV system. Parametric analysis explores the influence of atmospheric parameters, such as wind speed, solar radiation, and, relative humidity on passive radiative cooling of PV panels. Adoption of PDMS and PET coatings with 200 μm film thickness increases the transmissivity of glass in the solar band gap, maintains relatively higher thermal emissivity in the first and second atmospheric windows bands, and improves radiative cooling of PV panels. At low values of solar radiation, radiative cooling is shown to be capable of maintaining the cell temperature at values lower than the ambient temperature. A case study conducted to simulate nocturnal and daytime thermal behavior of PV modules shows the potential of radiative cooling integrated into PV modules under the specific hot and humid weather conditions of Jeddah, KSA. Temperature reductions of the PV panel by about 10 °C below the ambient temperature can be accomplished on summer nights using radiative cooling. Adoption of PDMS and PET coatings slightly improves the temperature reductions by up to 1.15 °C in the case of PET and 1.35 °C in the case of PDMS.

Keywords

• Passive radiative cooling
• PV solar cells
• Polymer coatings
• Design
• Thermal modeling
• Performance evaluation