Solar photovoltaic cooker: Technical analysis of a system suitable for institutional cooking

The paper presents a technical analysis of the use of solar PV power for cooking. It offers a comprehensive understanding of the design and functionality of the system. The study is focused on a solar cooker suitable for institutional cooking. The PV power was connected to a heating element inserted inside a pipe referred to as a heating funnel. At the top of the heating funnel is a cooking unit. The funnel was designed to allow a small volume of oil to be heated. The oil attains temperatures above 120 o C in a short time. When solar irradiance is high, the heated oil in the funnel is allowed to overflow into a heat storage tank. However, when solar irradiance is low, overflow of the hot oil into the tank is limited. This allows cooking to be done even during periods of low solar irradiance. The heating element, 4.3 ohms with a power rating of 1.2 kW, was connected via an MPPT load controller to a 1.8 kW solar PV array. Cooking tests were demonstrated under various weather conditions. 10 L of water was boiled in about 1.3 h during cloudy conditions. About 0.82 kWh of energy is used in boiling 10 L of water. On sunny days, the heating power generated was in the range of 0.8 kW to 1.2 kW. To enhance the safety of the system during use, the design of the cooking unit was modified to include double pots or a pot-in-pot. The pot-in-pot allows for the complete sealing of the top of the funnel, therefore, limiting the exposure of the hot oil to air or water. Cooking experiments and simulations with the double pots showed that the system is effective when the space between the pots has a small quantity of sunflower oil, which is in direct contact with the bottom of the cooking pot. 2 L of water was boiled in about 28 min using the double pots. Subsequent cooking tests took less time due to the improved heat transfer between the pots.