The aim of this Master Thesis is to find the most suitable amount of photovoltaic (PV) panels to sustain an off-grid thermal energy storage (TES) system and to compare a maximum power point tracker (MPPT) with a pulse width modulator (PWM) in order to analyze which one of them that best suits the system. The purpose is to provide feedback on the design of the electrical part of the system in order to make it suitable for testing in a school in an Uganda refugee camp. This is done by developing a simulation model and by performing an economical analysis of the system. Additionally, visits to the considered refugee camps are done. The results are based on data from the camps and interviews at the Physics department at Makerere University and consider the number of meals cooked by the TES as well as economical profitability and payback time. The recommended amount of PV panels is nine and the recommended controller is an MPPT. The simulation shows that the system reaches a point where an increasing number of panels doesn't increase the number of cooked meals by much. The economic analysis shows that this small increase is not enough to make up for the extra costs of adding more PV panels. Having a lower cost, PWM is preferred in the early years by the economic analysis. However, having a low efficiency, it is less superior to the MPPT. The payback time and revenue are better for the MPPT in the investigated cases. It is important to consider that the model doesn't show reality to a full extent. Experiments are made where it is found that the model is inaccurate on an hourly level but can be considered valid over longer periods of time. When choosing the results, a trade-off is made between maximizing the revenue or shortening the payback time of the TES system. Considering rough circumstances and the uncertain future of the camps existence, short payback time is chosen. This results in nine panels being the optimum amount. However, if the aim is to maximize revenue, twelve panels are better than nine. The price of firewood is a factor of uncertainty which this study relays a lot on and it's thereby important to consider when reading the results. Suggestions for future studies are to investigate the price development of firewood further or to test the use of stones in the thermal storage tank to decrease costs. Additionally, possible utilization of surplus produced energy from the system could be investigated in order to find extra benefits from the installation.