Numerical Optimization of a PCM-Based Box-Type Solar Cooker
Description
The present study numerically investigates and optimizes the thermal performance of a box-type solar cooker integrated with phase change materials (PCMs) to enhance cooking efficiency and extend operation beyond peak solar hours. A comprehensive multiphysics model is developed in COMSOL Multiphysics, incorporating heat transfer in solids, surface-to-surface radiation, natural convection losses, and PCM phase change using the apparent heat capacity method. The model is first employed to optimize key design parameters, including glazing thickness, absorber plate thickness, pot thickness, material selection, and cooking load under both charging and discharging conditions. The optimized configuration consists of double glazing with 3 mm glass thickness and a 1.5 mm aluminium absorber plate, achieving favourable performance indicators (F₁ = 0.15 and F₂ = 0.38). Aluminium is selected for both absorber and pot due to its comparable thermal performance to copper, with lower weight and cost. A cooking load of 1.58 kg water is identified as representative for performance evaluation. The effect of PCM integration is examined using RT100, acetamide, acetanilide, and erythritol. While PCM incorporation reduces the peak water temperature compared to the non-PCM case (133–134 °C), it significantly enhances thermal regulation during the cooling phase. Among the PCMs, acetanilide exhibits superior late-hour performance, maintaining water temperatures of 66 °C at 10 h, 59 °C at 11 h, and 52 °C at 14 h. Cooking power analysis shows that the non-PCM case achieves the highest peak cooking power (53.2 W), whereas PCM-assisted systems demonstrate improved thermal storage. Standardized cooking power indicates that erythritol (57.6 W) and acetanilide (48.8 W) provide superior normalized performance. The study highlights that optimal PCM selection depends on matching melting temperature with the operating range, rather than latent heat alone, offering a physics-based framework for designing efficient solar cookers.
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Institutions
- Rajiv Gandhi Institute of Petroleum TechnologyUttar Pradesh, Raebareli