Stroom
A practical solar car for everyday use, with a 1‑2‑1 seating layout that cuts aerodynamic drag.
- Year
- 2015
- Role
- Concept vehicle design (BSc thesis)
- Client
- Nuon Solar Team
- Outcome
- 10/10 · UfD/Damen award 2016, 4th place
- 10/10
- thesis grade
- 2 m²
- of solar cells
- Cw 0.28
- drag coefficient
- 20–80 km
- per day on sunlight
In 2015, solar cars were mostly flat racing machines: fast, but uncomfortable and impractical. For the Nuon Solar Team I asked a different question: what would a solar car look like that people actually want to drive every day?
3D model — drag to turn it around
Who it’s for
I chose a target group: people with a second car. I asked 25 of them how they use it. Most drove less than 25 km a day, mainly for shopping and picking people up. That’s well within what the sun can deliver. And it isn’t a niche: research by the British Automobile Association (2015) showed that 2.5 of the 8 million second cars in the UK could be replaced by an electric car with a limited range. So why not a solar car?
Packaging is everything
In a normal car, the packaging is straightforward: engine in front, two rows of seats, luggage in the back. A solar car has little power, so it has to be very aerodynamic, while also offering as much roof as possible for solar cells. I cut every component (seats, luggage, wheels) at 1:10 scale and shuffled them around. Using the “fish trap” model, I narrowed them down to three directions: Wind, Veer and Fier.
Wind is the smallest. It chooses aerodynamics and low weight over space for solar cells: a bench for one and a half people up front, an 80 cm folding back seat, and luggage above the rear wheels, behind a small door in the side.
Fier uses the classic layout: two seats in front, a folding back seat for one adult and a child, and luggage space front and back. It chooses safety and lots of solar cells over the best aerodynamics.
Veer won: a teardrop shape with the driver between the front wheels, a folding bench in the middle and a single seat between the rear wheels. With both seat rows folded down, it carries things up to 2 m long. It combines aerodynamics with flexibility, and it grew into Stroom.
The result
The slightly overhanging roof holds 2 m² of solar cells, good for 20 to 80 km a day in the Dutch climate. Three seating modes switch it between groceries, everyday use and a four-person taxi. In a flow analysis with Autodesk Flow Design, Stroom came out at Cw 0.28, against 0.41 for a VW Up!, while offering more roof for solar cells. 7 out of 10 second-car owners said they would want one.
My client, the Nuon Solar Team, wanted to win a future cruiser-class race. So I also drew Stroom S: more solar cells, a carbon-reinforced body, six times the battery and a rounder nose.
To see it for real, I made a 1:10 model by CNC milling, spray paint and glue.
The thesis was graded 10/10 and won 4th place, and €1,500, in the UfD/Damen award for best TU Delft bachelor thesis of 2016. TU Delft’s journal Delta put the winners on its cover.
