James Madison University

Solar Power Engineering Project Wins Award

By: Daniel Vieth
Posted: March 5, 2014

As one of the most popular forms of sustainable energy, solar power has been heavily researched for its potential to reduce our dependence on non-renewable energy resources. In fact, according to the Solar Energy Industries Association (SEIA), the power we harvest from the sun is the cleanest and most abundant energy source in the world. As this technology has improved, many families have put solar power systems on their house to cut back on energy costs. When it comes to storing the power we harvest from the sun, however, there are still issues with chemical waste and pollutants being released from the system’s batteries.

PHOTO: Computer set up

To address this problem, JMU professor Dr. Jacquelyn Nagel and engineering student Benjamin Condro began conducting research exploring the possibility of making solar energy systems more sustainable during the summer of 2012 with funding from the Valley 25 x ‘25/IEER initiative. “The research objective of the work was to explore the technical challenge of sustainability as it relates to solar energy production, storage, and consumption,” explained Nagel. Together along with students Eric Leaman and Jack Cochran, the Fluid-Mechanical Energy Storage Project was born. After strong initial success, the project was recognized as one of the top five in the 2012-13 James Madison Innovations’ (JMI) Intellectual Property Incentive Program, a program designed to spur learning and academic achievement.

The Fluid-Mechanical Energy Storage Project is currently an engineering capstone project that set out to design a more sustainable residential solar energy system. The team of students and Dr. Nagel call this technology the ‘Two-Phase Energy System’. In essence, the system replaces the battery storage aspect of typical residential solar power systems with fluid-based energy storage, such as tanks of liquid or compressed air. “The idea is that our system will be much more sustainable than typical residential solar energy systems because chemical batteries produce huge amounts of waste and are made with hazardous and toxic materials,” said Leaman. According to Nagel, batteries for solar energy systems can only be recharged 400 to 1,000 times, meaning they must be replaced every 3 to 5 years. “A major advantage of the proposed system will be its ability to retain its initial capacity for energy storage [an indefinite number of times],” said Nagel.

Taking inspiration from the energy storing techniques implemented in large-scale electrical supply systems like power plants, the team set out to design more cost-efficient and environmentally friendly residential solar power storage systems. As stated in the name, this technology operates in two sustainable energy phases. While conventional residential solar energy systems take the excess electromagnetic energy generated from the sun and store it as chemical energy in battery banks, the first phase in the new system converts the solar power into mechanical potential energy using a liquid or compressed air. The second phase then lets the stored energy be converted back into usable electricity. “When electrical energy is needed, the system will release the fluid using the help of gravity [to] spin a turbine generator,” explains Nagel. “This approach addresses the weaknesses of cost and limited discharge cycles of chemical batteries.”

Compared to conventional solar energy systems, the benefits of the team’s Two-Phase Energy System includes improved safety to residents by eliminating toxic materials and fire hazards, lower maintenance costs and smaller energy bills in the long run, a much longer operating life, less demand for carbon-emitting fossil fuels, and less battery waste being put into landfills. If taken to the next level, this new kind of solar energy system could even be used in developing nations where off-grid applications are the only means of electrical energy. For example, if a partnership could be formed with the non-profit organization Solar Electric Light Fund (SELF), the Two-Phase Energy System could be deployed to those individuals living in energy poverty. “[This could] make a notable impact on the environmental, social, and economic sustainability of developing countries,” Nagel explained. 

PHOTO: Plumbing

The Fluid-Mechanical Energy Storage Project is still going strong, working towards making the system as cost effective and energy efficient as possible. To measure this, mathematical models using typical energy output-over-energy input efficiency values were first used to  estimate system parameters, such as reservoir volume and pressure requirements. Based on the results, different components for evaluation in a full system model were selected. The dynamic systems-level model was then used to estimate energy output and efficiency as a function of changing system parameters using specifications of actual commercial components. “The expected output of the project will be a working prototype of the Two-Phase Energy System,” said Nagel. This prototype, which is currently under construction, will be used for mathematical validation as well as data collection for efficiency analysis. It will use solar energy to power a high-head pump to circulate water between high and low elevations.

The winning projects of the JMI Intellectual Property Disclosure Incentive Program are voted on by a subcommittee of the JMI Board of Directors, taking into consideration factors such as academic, business, and commercialization potential. With these in mind, it should come as no surprise that the Fluid-Mechanical Energy Storage Project was recognized as one of the top five at the university.

*The Fluid-Mechanic Energy Project was supported by ‘Shenandoah Valley as a National Demonstration Project Achieving 25 Percent Renewable Energy by the Year 2025,’ under the U.S. Department of Energy Grant #DE-EE0003100. The Views expressed are those of the authors, and do not necessarily reflect those of the sponsors.

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