The airplanes flying every day through commercial air routes for the civil transportation emit exhaust discharge gases increasing the pollution of the atmosphere and, thus, of the air that all of us breathe. Electronics technology may solve this issue in the near future, by means of an important contribution to the autonomous airplane. A first good example is represented by the air vehicle powered with hydrogen fuel cells of the German Aeronautics and Space Research Center (DLR), which is currently developing a fuel cell-based research platform:
“Electrically powered, locally emission-free passenger aircraft are set to make the transport of the future more sustainable and flexible. They have the potential to bring electromobility to the skies in the coming decades, networking with ground-based transport carriers, and thus making travel faster and easier for passengers. Researchers at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) are currently working with partners from industry and research institutions on the development of the HY4 test platform.
The HY4 – a four-seater passenger aircraft prototype – is due to take off for its maiden flight in the summer of 2016, using an electric propulsion system that draws most of its energy from a hydrogen fuel cell. The DLR Institute of Engineering Thermodynamics and research and development partners Hydrogenics, Pipistrel, H2FLY, the University of Ulm and Stuttgart Airport, are presenting a model of the HY4 at the Hannover trade fair on a shared stand for hydrogen, fuel cells and batteries (Hall 27, Stand E65).” (Source: dlr.de)
The HY4 – A zero emission electric propulsion system hydrogen powered by fuel cells (Source: DLR)
The direction of energy self-sustainable aircraft has been indicated by another very interesting air vehicle that is autonomous and it is powered with solar cells that showed efficiency up to 31% during flying tests:
“Alta Devices (Sunnyvale, CA) has achieved a 31.6% solar energy efficiency record, which could drive changes in the fundamental economics of operating Unmanned Aerial Vehicles.
Alta believes that the combined thinness and flexibility of the solar cell design will help redefine how solar technology can be used. Alta’s solar technology is attracting interest in the UAV (unmanned aerial vehicle) market. The increased power-to-weight ratio of Alta’s technology enables different possibilities for an aircraft using the solar cell technology compared with any of the other solar power options. ” (Source: Smart 2.0)
To further increase the energy efficiency of solar cells a new research about nanocavity materials may help (see Figure 3):
“The engineers used a single layer of molybdenum disulfide (MoS 2), a two-dimensional semiconductor that is commonly used in lubricants and steel alloys, on top of a photonic structure called an optical nanocavity made of aluminum oxide and aluminum. This nanocavity is an arrangement of mirrors that allows beams of light to circulate in closed paths, and the addition of the MoS 2 layer increases the amount of light that ultrathin semiconducting materials absorb. In turn, this could help industry to continue manufacturing more powerful, efficient and flexible electronic devices.
The 2D layer boosts absorption of light to 70% at 450nm, boosting the energy available for conversion and, potentially, the overall efficiency of a solar cell.” (Source: EETimes Europe)
The nanocavity structures (Source: EETimes Europe)
The “nanocavity” materials might be utilized for realizing a high efficiency of the power conversion and management of the solar light gathered by the solar cells integrated in the AEV.
The research is exploring the possibilities offered by new materials to increase the efficiency of the power conversion and, thus, the autonomy of the AEV.
In the part 2 of this blog series I will deal with further applications of electronics technology to the airplane with very low impact on the environment to preserve the quality of our air.