Development and thermal performance of a portable solar cooker using glycerol-erythritol phase change material

Abstract

This study presents a portable and thermally efficient solar cooking system that employs a 25 wt% glycerol-erythritol mixture as phase change material (PCM) for thermal energy storage. The solar cooker utilizes a box-type solar collector to absorb solar radiation and store energy in the PCM. A two-dimensional transient heat transfer model was developed to analyze temperature profiles during cooking. The simulation results showed good agreement with laboratory experimental data and guided the design of a solar cooker capable of preparing meals for two people. Because erythritol's relatively high melting point limits its ability to fully absorb solar energy under typical solar radiation, glycerol was introduced to reduce the melting point. A prototype solar rice cooker accommodating two servings was fabricated and tested under three conditions: (i) direct solar energy without PCM, (ii) sun-exposed pre-melted 25 wt% glycerol-erythritol PCM with non-solar cooking, and (iii) sun-exposed pre-melted 25 wt% glycerol-erythritol PCM with solar cooking. MATLAB simulations were used to model transient heat transfer and temperature distribution during cooking. Experimental results indicated that condition 3 was the most effective cooking method. Under condition 1, rice was fully cooked in approximately 240 minutes, while condition 2 produced undercooked rice due to incomplete PCM melting. Overall, this study demonstrates the feasibility of integrating PCM with solar energy to improve cooking efficiency, contributing to the advancement of sustainable, off-grid cooking technologies.