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
Energy produced	1	4	5	3	2
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 mobile 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
  • - 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.
  • - The most expensive was no.5, the double blade turbine because it needs 4 blades and is the highest
• • Energy produced:
  • - The most efficient is no.1 because generates the biggest amount of energy
  • - The least efficient is no.3 because of the shape of the blades (semi-curved and not semi-circle)
• • Wind speed needed
  • - The most efficient are no.1 and no. 5 because they need the lowest wind speed
  • - The least efficient is no. 2 because the blades are curved and not semi-circle
• • Technical aspects
  • - The mist efficient is no. 5 (design) with the blades at 90° and the biggest surface of wood lamina
  • - 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
February	1,1	2,6	4,0
March	1,9	2,5	4,4

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
February	-2,1	4,2	6,0
March	1,9	5,2	7,1

Conclusions regarding the 6th turbine model (waste magnets, plastic induction coil):

• It is more environmental friendly in confront with the other 5 models (ALL the materials are taking from wood, plastic and electrical devices waste)
• It is the most effective (it produce the larger amount of energy and can switch on the major number of LED) – we register 1, 23 J
• We don’t have to use a dynamo to convert mechanical energy into electricity
• It is the less expensive (less than 1 EUR for the nails)
• Can be use for small devices (single light bulbs or small number of LED)
• Can be put in a series for a bigger amount of energy
• Can be placed nearby the windows