A report on thermal heat storage and energy utilisation in a PV heat dual storage solar tank cooker

Abstract

Access to clean, sustainable, and affordable energy remains one of the most critical challenges in the developing world. In many rural and peri-urban areas of Uganda and similar regions, the majority of households continue to rely on traditional biomass fuels—such as firewood, charcoal, and agricultural waste—for daily cooking needs. These conventional energy sources, while readily accessible and familiar, are associated with a multitude of negative consequences. Environmental degradation due to deforestation, harmful emissions from combustion, increased health risks from indoor air pollution, are all pressing issues that highlight the urgent need for alternative cooking solutions. Furthermore, the energy crisis in sub-Saharan Africa is compounded by population growth, urbanization, and the over-dependence on unreliable grid electricity and fossil fuels. This has placed an immense strain on national energy infrastructures, making energy security a top developmental priority. The adoption of solar energy for cooking presents a viable, clean, and locally available solution that addresses both environmental and socio-economic concerns. For solar cooking technologies to be practical and widely adopted, they must be equipped with efficient thermal storage systems capable of storing and releasing heat on demand. To address this gap, the development of a dual tank PV-powered heat storage system was undertaken to explore a model of solar cooking that is both technically feasible and responsive to local cooking habits. This system is designed to store solar energy in the form of heat using synthetic oil as the heat transfer fluid, which is then used to cook food even after the sun has set. The dual tank configuration allows for greater flexibility, improved heat management, and the potential for sequential energy use—enabling households to cook multiple meals per day without relying on sunlight during every cooking event. Unlike traditional solar cookers, which rely solely on direct sunlight and are often limited by weather conditions and time-of-day constraints, the proposed dual tank system is designed to store surplus energy during peak sun hours and release it when required—thereby aligning with real-world cooking patterns. The need for such innovations is further emphasized by global commitments to sustainable development, climate action, and universal access to clean energy. The United Nations Sustainable Development Goal 7 (SDG 7) aims to ensure access to affordable, reliable, sustainable, and modern energy for all by 2030. This project directly supports that vision by developing a decentralized energy solution that reduces reliance on wood-based fuels, lowers greenhouse gas emissions, and promotes health and gender equity by eliminating the need for firewood collection and exposure to indoor smoke. Additionally, by shifting cooking energy demand from biomass and fossil fuels to renewable sources, communities can reduce pressure on natural resources, improve food security through more reliable cooking, and build resilience to climate change. Therefore, the motivation for this project is not only grounded in technological advancement but also in a commitment to social, environmental, and economic sustainability. The insights gained from this research are intended to support future innovation, inform policy direction, and catalyze the adoption of cleaner cooking technologies across Uganda and beyond.