Design of a two-phase solar and fluid-based renewable energy system for residential use

This project explores the technical challenge of sustainability as it relates to solar energy production, storage, and consumption. The challenge is addressed through the design of a two-phase renewable energy system that can provide electrical energy during both day and night without the use of chemical batteries. “Phase One” is the conversion of solar energy into electrical energy using photovoltaic panels for both immediate supply to the household load and for storage in a fluid based system. “Phase Two” is the conversion of the stored potential energy back into electrical energy. Methods of energy storage evaluated include pumped-hydroelectric energy storage (PHES) and compressed-air energy storage (CAES). Mathematical models using typical energy efficiency values are first used to estimate system parameters such as reservoir volume and height or pressure requirements. Based on the results, components and the methods of energy storage for further evaluation are selected. A dynamic systems-level model is then used to estimate energy output and efficiency as a function of changing system parameters. This model is validated by simulating full-scale conditions using a fluid reservoir and a pump. PHES has been chosen as the method of energy storage based on a high-level analysis. Efficiency of the turbine-generator was experimentally found to be as high as about 32% but was shown to increase with increasing hydraulic head. This demonstrates that the system could be a viable replacement for conventional batteries in poor or remote locations, especially if local topography allows for low-cost installation of a raised water reservoir.