Alternative Energy

The progress is being steadily made in the field of alternative energy. Though we have not hit the bull’s eye yet but still the search is on. Scientists and researchers all over the world are spending sleepless nights on their projects to find an all-pervasive alternative to fossil fuels. How can we utilize the alternative energy technology for unmanned aerial vehicles (UAVs) When we think about the unmanned aerial vehicles (UAVs) we think of saving human resource, undoubtedly the most precious resource of any nation. But UAVs have some drawbacks too. They can’t fly to the far and distant places because after traveling certain distance an aircraft needs refueling. And here we face the disadvantage of UAVs. They can’t refuel. But if they utilize solar energy they can travel more and work more effectively in enemy’s territory. The Air Force is thinking of using Dye-sensitized solar cells (DSSCs) for unmanned aerial vehicles (UAVs) in future. Then they can fly for a longer duration of time without refueling.

This project is undertaken by the University of Washington’s Multidisciplinary University Research Initiative (MURI) team. The lead researcher Dr. Minoru Taya is working on airborne solar cells by utilizing a flexible film and a thin glass coating with transparent conductive electrodes. He has reached to the conclusion that DSSCs are able to grab photons and convert them into synthesized electrons that can harvest high photon energy. What does Taya think about his project? He shares his thoughts, “These kinds of solar cells have more specific power convergence efficiency (PCE), very clean energy and easy scalability to a larger skin area of the craft, as well as, low-temperature processing, which leads to lower costs overall.”

DSSCs are generally made from organic materials such as dyes and moth-eye film. The team has been working on this project for some time. Their earlier attempts were unsuccessful because glass based solar cells were too heavy and their toy airplane refused to be airborne! Though the propeller was working satisfactorily. Later on they switched over to film battery technology which was a hit and plane was indeed flying. The team is concentrating its efforts on DSSCs with higher PCEs using bio-inspired dyes, which are installed in the wings of the UAV (airborne energy harvesters). What are the main characteristics of airborne energy harvester? According to Taya, “Any airborne energy harvester must satisfy additional requirements, like weight and durability in airborne environments. If those are met, then there may even be longer UAV flight times.”

The engineers working on this project are researching the challenges of DSSCs’ technology. They are trying to gauge the durability and how well their technology may integrate with other Air Force vehicles. The team is also trying to find the technical knowhow of building the solar cells in the wing surface of the aircraft and how to store energy harvested from them.

Taya is hopeful that, “Some of these challenges will be overcome by the researchers working under this AFOSR MURI within the next two years. In order to make the DSSCs’ solar energy harvester transferable to the wings of an UAV, additional engineering tasks remain, which may require another project to be funded for five additional years.”