Nuna7 is the first four-wheel solar car of the Nuon Solar Team and has won the World Solar Challenge 2013. This solar car was the first car which used a lens-system called concentrators, which provided us with more energy income that the competition. The revolutionary asymmetrical design secured the minimal air resistance Nuna is known for. Nuna7 crossed the finish line in a time of 33 hours and 3 minutes, which equals an average speed of 90.71 kilometers per hour.
Because of the restrictions on the dimensions of the solar car, the seventh Nuon Solar Team could not fill the topshell of the solar car with the maximum allowed area solar cells of 6 square meters. The area of approximately half a solar cell was left unused. To use this last bit of area, the team used concentrator systems from Semprius. This is a lens-system with concentrates a large area of sunlight on a very small area of Gallium Arsenide solar cells. These concentrators are unfolded when the solar car is standing still, during the control stops and during the morning and evening. The concentrators proved to be an innovation the competition had not anticipated for.
Since the regulations demanded a four-wheel design, the aerodynamic layout has changed dramatically. An asymmetrical design proved to have the lowest air resistance, so the driver is positioned on the right side of the car, while the electronics are positioned on the other side. This provided us with a great challenge for the stability and steering system of the car, which had to go from the drivers compartment through a tiny cross-section towards the other side of the car. Through this design the team had an aerodynamic advantage which contributed to our victory.
The solar panel on top of the car is also optimized. The SunPower cells were of unmatched efficiency in the world. An extra advantage was a new encapsulation around the solar cells. Next to the previously used Gochermann encapsulation, we used a new experimental encapsulation of SunCat. This encapsulation from the United States had en even higher efficiency.