At the beginning of the project we asked ourselves the following questions:
  • • Which is the best size of the PET bottles we need to use for the production of a Savonius turbine?
  • • How strong should be the wind in order to built an effective Savonius turbine?
  • • How much energy produce a Savonius turbine (per hour/per day)?
  • • What are the costs for producing a Savonius turbine? But a series of Savonius turbine?
  • • What do we do with the energy produced?
  • • Where can we place the Savonius turbine?

Models of turbines

1. a turbine with 4 blades made from 5 l plastic bottle, diameter of the bottle 135mm
2. a turbine with blades made from 3 l plastic bottle, diameter of the bottle 95mm
3. a turbine with blades made from 2.5 l plastic bottle, diameter of the bottle 82,5mm
4. a turbine with blades made of PVC pipe of 100mm diameter
5. a turbine with 2 vertical blade steps made of PVC pipe of 110mm diameter
Savonius turbine
Characteristics 1 2 3 4 5
Wind speed needed 1 5 4 4 2
Technical aspects 2 5 4 3 1
Costs 3 2 1 4 5
Costs 3 2 1 4 5
Turbine
1 2 3 4 5
Observations Fixed axel, mobile bearing
Dynamo entrained by fixed axel
Fixed axel, mobile bearing
Dynamo with direct contact on the turbine’s frame
Fixed axel, mobile bearing
Dynamo entrained by fixed axel
Blades surface is larger, mobile axel, fixed bearing
Dynamo entrained by fixed axel
Blades placed at 90° angle
Dynamo entrained by fixed axel
The cost of each turbine (euro/$) 7euro 6.5euro 5euro 7.5euro 8euro

Costs/benefits analysis

  • • Costs
    • o The most efficient from the costs point of view is no. 3, made of 2,5l bottle because we use less material to make it.
    • o The most expensive was no.5, the double blade turbine because it needs 4 blades and is the highest
  • • Energy produced:
    • o The most efficient is no.1 because generates the biggest amount of energy
    • o The least efficient is no.3 because of the shape of the blades (semi-curved and not semi-circle)
  • • Wind speed needed
    • o The most efficient are no.1 and no. 5 because they need the lowest wind speed
    • o The least efficient is no. 2 because the blades are curved and not semi-circle
  • • Technical aspects
    • o The mist efficient is no. 5 (design) with the blades at 90 and the biggest surface of wood lamina
    • o The least efficient is no. 2 because the dynamo is in direct contact with the frame

Results and discussions

In order to research the meteorological conditions, we register the wind speed by using an anemometer and direction and the air temperature for almost one year.

Wind speed (m/s)
Month Min Average Max
June 0,75 2,5 4,1
July 0,8 3,1 4,4
August 1,1 1,9 3,9
September 1 3,7 4,3
Octomber 1,1 2,2 3,8
November 1,3 2,8 4,5
December 1,8 3 6,9
January 1,2 2,8 4,1
Temperature (°C)
Month Min Average Max
June 17,3 23,9 26,2
July 19,9 25,1 28
August 21,9 26,1 29,2
September 13,9 22,5 24
Octomber 8,1 14,8 20,1
November 5,9 14,9 17,8
December 2,8 7,3 8,4
January 2,8 7,3 8,4