Techno-Economic Viability of a Solar Thermal Steam Kitchen for Rural Schools of the Global South

Abstract

Combustion byproducts of cooking indoors are a major cause of respiratory illness in women and children of the Global South. The use of direct-fired woody biomass cooking appliances at institutions such as schools is the predominant method for cooking, however, several initiatives seek to convert fuels by installing liquified petroleum gas (LPG - propane) burners. Where there is a high level of direct normal irradiance (DNI), concentrated solar power (CSP) offers the opportunity to use the sun’s heat energy for cooking to maximize energy sovereignty. This paper describes a CSP technology that uses a newly-designed small-scale parabolic trough collector made primarily of common commercial greenhouse materials that is shipped in a compact form and assembled by local labor on site. The assembled array directly generates steam for steam-jacketed kettles- a simple technology well suited to stewing tough meats, legumes, and vegetables typical to the cuisine. Thermal storage, in the form of a Ruths-type steam accumulator, is employed in the system design. The characteristics and economics of a system for a primary school in Eswatini are postulated and modeled demonstrating operational feasibility while highlighting the requirement for fuel use to cost more than its market price or capital costs to be subsidized to provide a positive return on investment.