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Nuna7

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Nuna7

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.

Dimensions
  • 4.5 x 1.8 x 1.12m (l x w x h)
Weight
  • 180kg
Driver
  • Weight will be supplemented to 80 kg
Number of wheels
  • 4
Solar cells
  • 392
Motor
  • InWheel Direct Drive Electric Engine
  • Integrated motor in rear wheel
  • Efficiency: 98%
Battery
  • 21 kg Lithium Ion cells
  • Capacity: 5.3 kWh
  • Intelligent and efficient battery management system
Control
  • Intelligent carbon fibre steering wheel with quick-release
Body
  • Sandwich construction with carbon fibre and foam
  • Special carbon fibre weave ‘TeXtreme’ which is also used in Formula 1 cars
  • Aramid reinforced parts to protect the driver and prevent chippings
  • Titanium roll bar
Aerodynamics
  • Specially designed wing profile
  • Revolutionary asymmetrical design
  • Tested and proven in the windtunnel
Suspension
  • Aluminium uprights, hold by aluminium leading arm below with single A-arms of carbon fiber
  • Integrated dampeners in suspension
  • Lightweight magnesium rims
  • High precision ceramic bearings
  • Titanium axles
Tyres
  • Low resistance profile tyres specially developed with Michelin for solar racing
Brakes
  • Regenerative braking with the electric motor
  • Mechanical brake for emergencies
Rolling resistance
  • Over 10 times smaller than a conventional vehicle
Air resistance
  • Over 11 times smaller than a conventional vehicle
Telemetry
  • Wireless connection with support vehicle
  • Support vehicle determines the speed of Nuna using touch screen application
  • Board computer with all data of the car
Driver comfort
  • NACA-duct: Low drag air intake for fresh air in the cockpit

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