Refraction-Assisted Solar Thermoelectric Generator based on Phase-Change Lens

Area of Science:

• Materials Science
• Renewable Energy Engineering
• Optics

Background:

• Solar thermoelectric generators (STEGs) are crucial for small electronic devices, requiring high energy conversion efficiency.
• Optical concentration systems are vital for improving STEG performance.
• Phase-change materials (PCMs) offer tunable optical properties with temperature variations.

Purpose of the Study:

• To design and investigate a novel refraction-assisted STEG (R-STEG) utilizing phase-change materials.
• To leverage the changing optical properties of PCMs during phase transition for enhanced solar energy concentration.
• To improve the energy conversion efficiency and energy storage capabilities of STEGs.

Main Methods:

• A refraction-assisted STEG (R-STEG) was designed incorporating a phase-change material (PCM) lens.
• The optical properties (refractive index, transmittance) of the PCM were analyzed during its solid-to-liquid phase transition.
• Solar energy concentration was achieved through double focusing via an optical lens and the PCM lens.
• Energy conversion efficiencies were measured at different solar intensities (1 and 1.5 kW/m²).

Main Results:

• The R-STEG demonstrated significantly higher peak energy conversion efficiencies compared to typical STEGs.
• Efficiencies were 60% higher at 1 kW/m² and 86% higher at 1.5 kW/m² solar intensity.
• The stored energy in the PCM enabled steady electrical energy generation even after solar energy removal.

Conclusions:

• The developed R-STEG design shows substantial progress in optical characteristics of PCMs for solar energy concentration.
• This innovative approach enhances STEG efficiency and provides a mechanism for continuous power generation.
• The study highlights the potential of PCMs in advanced optical concentration systems for renewable energy applications.