Thermoelectric‐Based Measurement and Sensitivity Analysis of Heat Transfer Coefficients in Solar Irregular‐Shaped Cavities

This study introduces a novel approach for estimating the total, convective, and radiative heat transfer coefficients within solar irregular‐shaped cavities, leveraging thermoelectric technology. The method relies on a steady‐state thermodynamic model incorporating the Seebeck effect, with thermoelectric module parameters obtained from datasheets and validated experimentally. Surface emissivity and convective boundary conditions were assumed based on standard literature values. By employing a steady‐state thermodynamic model, empirical correlations for these coefficients were derived based on measurable parameters such as thermoelectric voltage, ambient temperature, and glass temperature. The derivation of these correlations is grounded in energy balance principles and assumes uniform heat distribution across system components. The proposed methodology is designed for irregular‐shaped cavities with varying dimensions and thermal conditions, indicating its potential for a wide range of configurations. To validate the derived correlations, a representative case study and experimental validation were conducted using a solar pyranometer as a specific case of an irregular cavity under real‐world conditions (nine data points over a winter day). Conducted under steady‐state conditions, sensitivity analysis revealed that electrical voltage and glass temperature are the most influential parameters, while ambient temperature had a lesser impact. The experimentally measured heat transfer coefficients ranged from 1.72 to 14.05 W/m 2 ·K for total, 0.90 to 13.11 W/m 2 ·K for convective, and 0.82 to 0.96 W/m 2 ·K for radiative heat transfer. The proposed correlations predicted the convective and total coefficients with average deviations of 10% and 9%, respectively, and the radiative coefficient with only 2% deviation. Additionally, the hot‐side temperature of the thermoelectric module was estimated with an average error of just 0.5%. This method provides a practical, low‐cost, and accurate framework for heat transfer analysis in solar energy systems.