Experimental characterization of a foldable solar cooker with trapezium cooking chamber and adjustable reflectors

In this study, a portable and easy to construct solar cooker is presented as an alternative to traditional cooking methods to be used in humanitarian contexts, in order to face the issue of humanitarian goods transport and storage. The prototype consists of a trapeziumshaped cooking chamber and adjustable reflector panels made of inexpensive and readily available materials. The solar cooker was designed to be foldable and easily transportable by using lightweight materials. In fact, the folded prototype is compact having a lightweight of 7 kg. This allows to transport up to 124 units on a single pallet (Euro-pallet size) to the desired location. Several experimental tests without and with load (water and glycerin) were conducted using a black pot placed inside the cooking chamber, which has high area of clear glass, to evaluate its thermal and optical performances. During the tests without load, the highest temperature recorded for the studied prototype was 149.38 °C and the corresponding first figure of merit F1 was 0.13 °C/(W/m²). The solar cooker loaded with 1 kg of water at 40 ºC took 115 minutes to reach 90 °C, being the average values of standardized cooking power and second figure of merit F2 equal to 7.40 W and 0.18, respectively. The standardized cooking power was calculated using an equation derived from the Hottel-Whillier-Bliss formulation. Meanwhile, the prototype loaded with 1 kg of glycerin at 40 ºC took an average of 122 minutes to reach 105 °C, being the average standardized cooking power and average of second figure of merit F2 equal to 13.19 W and 0.2, respectively.