Design of a parabolic solar cooker for developing countries

In rural Sub-Saharan Africa, over 80 % of households rely on firewood and charcoal for daily cooking, causing severe deforestation, adverse health impacts from smoke inhalation, and socio-economic burdens. This work presents the thermodynamic sizing, mechanical design, material selection, and prototyping of soL4Ar, an off-grid parabolic solar cooker developed within the student non-profit association LEDS for Africa (University of Padua) for rural deployment in the coastal Biombo region of Guinea-Bissau. To meet the cultural and nutritional requirements of a 6–10 member household (boiling 1.2 kg of rice and enabling high-temperature grilling up to 300 °C), the system was sized under local climatic boundary conditions of wind and sand erosion. A deep paraboloid geometry (aperture diameter D = 1.30 m) was selected to minimize glare hazards and shield the cooking vessel from wind dissipation, sinking two-thirds of the pot to reduce convective losses. Accounting for useful heating power, radiation, and optical losses, the required thermal power is 781.3 W with an overall optical efficiency η_o= 71.3 %. Material selection tackled the severe coastal environment characterized by airborne quartz sand abrasion and saline corrosion. Commercially pure Aluminium 1050 H18 temper was chosen for the reflective petals, providing both high specular reflectance and structural resilience against storm wind gusts. The supporting structure was engineered from marine-grade 5000-series aluminium to ensure galvanic compatibility and resistance. A prototype was constructed using 16 elastic trapezoidal sectors shaped over radial parabolic ribs clamped between dual toothed central disks. The design prioritizes local maintainability and modularity, employing planar sheet-metal cuts, a single-axis polar tracker with 15-minute discrete pin indexing, and an intuitive interlocking assembly requiring only eight structural bolts.