Delft University of Technology - Technische Universiteit Delft



Founded in 1842, the Delft University of Technology, in Delft, the Netherlands, is one of the oldest, largest, and most comprehensive technical universities in the Netherlands, with over 13,000 students and 2,100 scientists (including 200 professors). The university is a member of the IDEA League.









Public, technical

Rector J.T. Fokkema


ir. G.J. van Luijk






Delft, The Netherlands




Nuna is the name of a series of manned solar powered vehicles that won the World solar challenge in Australia three times in a row, in 2001 (Nuna 1 or just Nuna), 2003 (Nuna 2) and 2005 (Nuna 3). The Nunas are built by students of the Delft University of Technology.



Nuna 3 - superb solar car design



Nuna 3 (2005)


Nuna 3 was one of the favourites for the 2005 edition of the World Solar Challenge with a pre-race test-drive speed of 130 km/h. The final result was that the 3021 kilometers between Darwin and Adelaide were covered in a record 29 hours and 11 minutes, averaging about 103 km/h.


It has improved solar cells of a type that is otherwise only used in artificial satellites (as had the previous Nunas), and it has better aerodynamics and a lower weight than its predecessors.


It was designed and built by 11 students from different disciplines of the Delft University of Technology, who have partly put their studies on hold for this. They used the hightech labs and workshops of the University and, as with the Nuna 2, they received advise from Wubbo Ockels, the first Dutch astronaut and professor at the University.



Main specifications




5 x 1.8 x 0.8 m

(l x w x h)


< 200 kg

Air friction coefficient


comparison: this value is between 0.25 and 0.35 for modern cars

Solar cell efficiency

> 26%

this is close to what is theoretically possible and is determined by the qualities of the material used (in this case GaAs is used). The efficiency of most panels is 15%

Engine efficiency

> 97%

comparison: an average electromotor has an efficiency of 85%

Battery capacity

5 kWh

comparison: an ordinary 24 kg car battery has a capacity of 80 Ah, which equals 1 kWh

Battery weight

30 kg



Design criteria


To have a good chance to win, the car has to:


  • collect as much solar energy as possible

  • use as little energy as possible to drive at a certain speed. This means special attention to:

    • the efficiency of transferring electrical energy to the wheels, and

    • minimizing friction, constituted by:


1) air friction (air resistance), and

2) rolling friction, which in turn is affected by the weight, among other things




The Nuon 2005 team at race course Zandvoort



Solar cells


The solar cells are made of Gallium Arsenide (GaAs) and consist of three layers. Sunlight that penetrates the upper layer is used in the lower layers, resulting in an efficiency of over 26%. This type of solar cell is among the best available at the moment. Apart from efficiency, size also matters, so the entire roof of the Nuna 3 is covered with them, except for the cockpit.


Efficiency is optimal when the cells are hit by the solar rays perpendicularly. If not, output is reduced by roughly the cosine of the angle with the perpendicular. Because the race is held in September this year (as opposed to October or November in previous years) the sun will be lower in the sky (it's earlier in spring). To compensate for this, as many cells as possible are placed at the sides, most notably on the wheel caps.


A solar cell gives a certain amount of current for a certain amount of sunlight. The voltage depends on the load (more precisely the resistance of the load). The power is the product of voltage and current and therefore also depends on the load. Over a certain voltage the current of the solar cell quickly drops to zero, as the graph illustrates.


However, the batteries have a fairly constant voltage, which also has a rather different value than that of the solar cells. So a voltage transformation is needed. Because this is direct current, a normal transformer, which uses alternating current can not be used.


Also, the DC-DC converter has to make sure the load the solar cells see is such that the solar cells give maximum power, so also at the top of the green line in the graph. The machine that does this is called the Maximum Power Point Tracker (MPPT). Here too, the goal is to have this conversion achieve maximum efficiency (>97%).



Aerodynamic design


The aerodynamic resistance is an important part of the total resistance. Important are the frontal surface and the streamline. Any deviation from the ideal streamline will cause turbulence, which costs energy. The ideal streamline is achieved in various stages:


  1. Through computer simulations of the design

  2. Through testing of a scale model in a wind tunnel. For example, liquid paints can be applied to see the flow of air over the surface. The photo shows is taken during one of those tests in the Low Speed Laboratory of the TU Delft.

  3. Through testing of the full scale car in a wind tunnel. For this a German-Dutch wind tunnel in Emmeloord will be used.


From meteorological data from the area where the contest is to take place, it can be concluded that there will likely be a strong side-wind. The wheel caps of the Nuna 3 are designed such that a sidewind will have a propulsory effect.





The engine is totally encased in the rear wheel to minimise loss through mechanical transmission from engine to wheel (such as in a normal car in the gear box and cardan). The engine is an improved version of a Swiss engine by Drivetek, a spin-off of the Hochschule für Technik und Architektur Biel. The improvements are a 30% lower weight (10 kg), 50% more power (over 2400 W) and a 45% higher torque. The efficiency of the engine is also improved and is now over 98%. But as the graph shows this depends somewhat on the speed and increases with speed.



Test drive


During one of the test drives in the Netherlands the Nuna 3 achieved a speed of 130 km/h. On the first day of the race the car achieved a top speed of 140 km/h.


The race


Winning the race requires not just a good vehicle but also a clever way of driving it, in accordance with the characteristics of the track. Which is why this has been researched for two months prior to the race. Height differences are mapped and linked to GPS data. From this, during the race, the optimal speed can be determined.


Despite all testing and other preparations, one uncertain factor remains; the weather. Any clouds would strongly influence the amount of sunlight that can be captured. So any weather changes along the track will have to be constantly monitored. All these data are analysed by a computer model that constantly computes the ideal speed for that moment. This equipment is built into (petrol powered) pilot cars. Through telemetry these constantly receive data about the condition of the batteries and the amount of captured sunlight.



Important opponents


The winner of the American Solar Challenge from the University of Michigan (USA) was considered to be one of the most important opponents. Other important contestants were the MIT (also USA) and the Japanese Ashiya University team. In 2005 there were also two other European contestants, the Dutch Raedthuys Solar Team from the University of Twente and the Belgian Umicore Solar Team from Leuven.



2005 Race monitor

  • 5 August 2005: the team arrives in Adelaide.

  • 2 September 2005: The road permit is granted.

  • 16 September 2005: During a test drive Nuna 3 strands in the rough next to the road. A defective wheel suspension turned out to be the cause. The damage was limited and repaired after a few days.

  • 22 September 2005: The Nuna 3 is approved by the organisation.

  • 24 September 2005: The Nuna 3 qualifies for the 8th starting position, which is better than the starting positions the previous two models got.

  • 25 September 2005: The Nuna 3 covered 827 km holding first place, leading the next-placed Michigan team by approximately half an hour.

  • 26 September 2005: On the second day the Nuna 3 covered 835 km, at an avarage speed of 105 km/h, which is a new single-day record for the World Solar Challenge. The Michigan team is now 132 km behind.

  • 27 September 2005: Nuna 3 covered 858km, beating yesterdays record. They extended their lead to two hours. 500 km to go.

  • 28 September 2005: Nuna 3 arrives as first car in Adelaide, thus scoring a hat-trick. The overall average speed of 103 km/h over 3.010 km means an improvement by 6 km/h of the 2003 record.















Aristotle Uni of Thessaloniki, Helios


Faculty of Engineering

Arizona Solar Racing Team - USA

Arizona Solar Racing Team

Auburn University

Sol of Auburn

Sol of Auburn

Aurora Team, Australia


Aurora Vehicle Association

Bochum Solar Car Team

Das SolarCar der Fachhochschule

California Poly S University

SLO Burn  Sidewinder

San Luis Obispo

Clarkson Uni Solar Car Team, USA

The Solar Knights

Delft University - Holland

NUNA I & II 2003

Dell Winston School

The Hunter

Solar Car Challenge

Desert Rose, Northern Territory Uni


Drexel SunDragon Home Page

École de technologie supérieure Quebec

Eclipse V (5)

Éclipse Vehicular Solaire 

École Polytechnique de Montréal


Eko-Auto  Poland


Electron Analytic Corporation

Dark Horse

EAC Skunkworks

George Washington University

George Washington Uni Solar Car

Georgia Institute of Technology

Solar Jackets

Solar Jackets

Heliodet, Germany


Heliodet, Solar Car Team

Helios - Lille, France

Hélios IV

Hautes Etudes d'Ingénieur

Honda Car Company


Illinois State University

Surya, Ratha, Mercury

Illinois State University Team

Iowa State University


Team PrISUm

Jonasun  Japan


Solar Car Paviion

Kansas State University


Solar Car Racing Team

Los Altos Academy of Engineering

Los Altos Solar Car Team

Massachusetts Institute of Technology



McGill University Monteal, Canada


Team iSun

McMaster University


McMaster Uni Solar Car Project

Messiah College Grantham, Penns

Genesis II

Genesis II Solar Racing Team

Michigan State University


Solar Racing Team

Michigan Technological University

Solar Car Team

Minnesota S Uni-Mankato/Winona S Uni

Minnesota Solar Car Team

North Dakota State University

The Double Deuce

Sunsetters - Solar Race Team

Northwestern University


Northwestern University

Nuon Solar Team, Netherlands

Nuna 3

Het Nuon Solar Team

Osaka Sangyo University, Japan

OSU model S

Solar Car Team

Prairie View A&M University


Sun Panthers

Principia College

RA 6

Principia College Solar Car Team

Purdue University


Purdue University Solar Racing

Queen's University Canada

Radiance  Gemini

Queen's Solar Vehicle Team

Red River College 

Red River Raycer

Red River College Solar Car Team

Rice University

Rice University

Rose-Hulman Institute of Technology

Rose-Hulman Solar Car Team

Southern Illinois Uni Edwardsville

Cougar Cruiser

Southern Illinois University

South Bank University, UK

Mad Dog

South Bank Mad Dog Team

South Dakota School Mines & Tech

Solar Motion

South Dakota Solar Motion Team

Southern Taiwan University Tech

Southern Taiwan Solar Team

Stanford University


Stanford Solar Car Project

Tamagawa University - Japan

Tamagawa Solar Challenge Project

Team Futura, Italy


Team Futura

Team SunLake - Japan

Phaethon model

Team SunLake TOYOBO

Texas A&M University

Columbia Sunraycer

Texas A&M Motorsports Team

The Power of One  - Toronto


The Xof1 solar car team

Tufts University


Nerd Girls

University of Alberta

University of Alberta Team

University of Arizona


Solar Racing Team

University of Calgary


UC Calgary Solar Car Team

University of California-Berkeley


California Calsol Team

University of Kansas

Solution, CATalyst

KSU Solar Car Racing Team

University of Kentucky

Gato del Sol II

Solar Car Team

University of Massachusetts 

Spirit of Mass 413

Lowell Solar Racing Team

University of Michigan


University of Michigan

University of Minnesota

Borealis III

U of M Solar Vehicle Project

University of Missouri Columbia

Suntiger VI

The Mizzou Solar Car Project

University of Missouri Rolla

Solar Miner V

Solar Minor Car Team 

University of North Dakota

Subzero 3

Team SubZero

University of Ontario Institute of Tech

UOI Solar Vehicle Team

Uni of New South Wales SCR Team

UNSW Sunswift III

New South Wales SCR Team

University of Patras, Hermes

Solar Car Team

University of Pennsylvania


Penn Solar Racing

University of Queensland


Queensland Solar Team

University of South Australia


SA Solar Car Consortium

University of Texas at Austin

Solar Steer

Solar Vehicles Team

University of Texas at El Paso



University of Toronto

Blue Sky

Blue Sky Solar Racing

University of Toulouse


Heliotrope Solar Car Team

University of Utah 


Vehicle Design Team Utah

University of Virginia


UVa Solar Car Team

University of Waterloo

Midnight Sun VIII

Midnight Sun Solar Race Team

University of Western Ontario


Sunstang USP Solar Car Team

USP Solar Car Team

USP Solar Car Team

Western Michigan University

Sunseeker 05

W Michigan Solar Car Team

Yale University

The John Lee

Team Lux













American Solar Challenge

American Tour de Sol

American World Solar Challenge - Formula Sun          

Australian World Solar Challenge

Canadian Solar Discovery Challenge

Dream Cup Solar Car Race Suzuka 2003 - Japan

Japanese World Solar Car Rallye

North American Solar Challenge

Phaethon 2004

Solar Express - Solar Bike Race


SunRace 2003 - Australia

World Solar Car Rally - Japan

World Solar Rallye - Japan




During these competitions, students learn about solar panels, electric motors, electronics, vehicle chassis, bodywork, aerodynamics, suspension, batteries and how to solve practical problems during the design process, while working as a team.  It's demanding stuff and more fun that laying in bed watching TV, where individuals may seek inspiration, but achieve very little.








1. Chassis - and seating

2. Mechanics - suspension, steering, brakes

3. Motor and drive train

4. Motor controller

5. Solar Array - usually part of body

6. Batteries or fuel cells

7. Electrical System - and instruments

8. Driver Controls - switches, lighting, etc

9. Bodywork - Screen, etc










Solar Cola - a taste for adventure




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