Nico Hotz, a Duke University engineer has developed a new rooftop hybrid solar power generation system that operates considerably differently than conventional photovoltaic (PV) solar panels. The system utilizes what looks like a typical rooftop PV array but the similarity ends there. The hybrid panel actually comprises a dense nest of copper tubing that carries a combination of water and methanol that is heated and catalytically stimulated to a reaction that produces hydrogen.
The hydrogen is used in fuel cells while it is produced during the day, with the excess being compressed and stored in tanks for use at night.
When discussing the system’s exergetic performance (a measure of how well a quantity of energy can be converted to useful work), in an article published by the Duke Pratt school of Engineering, Hotz said:
“The hybrid system achieved exergetic efficiencies of 28.5 percent in the summer and 18.5 percent in the winter, compared to 5 to 15 percent for the conventional systems in the summer, and 2.5 to 5 percent in the winter.”
Hotz’ hybrid solar power system allows for up to 95% of sunlight to be absorbed, resulting in temperatures within the tubes of up to 200 degrees Celsius, critical to the evaporation process for generating the hydrogen.
Comparing two alternative systems with Hotz’: one that generated electricity from PV cells in the traditional manner, and another that generated hydrogen via electrolysis, resulted in Hotz’ system prevailing relative to cost and efficiency if the system were designed to only meet summer demand. The solution would be more expensive than a classic fossil fuel system if it were designed to meet winter energy demands because more solar panels would be required. However, the owner of a hybrid solar energy system could potentially sell excess summer generated energy back to the grid which would make up for the higher initial capital investment.
Hotz’ project work is the type of thinking required in order for successful global migration away from fossil fuels. ReTech Power and Water Engineering applauds the work of Nico Hotz and his associates, recognizing that any goal truly worth achieving takes focus, work, trial, and error. This is one early case that has produced what appears to be a potentially viable result.