Modification and Testing of Wind Turbine with Double Savonius

Indonesia geographically located at tropical region where the wind is very fluctuate and relatively slow is important for designer to investigate the proper design of the slow wind speed turbine that applicable in Indonesia. In this paper, Savonius wind turbine is selected and modified with double level to explore its capability in generating voltage. The main aim of this study is to investigate the performance of the double Savonius turbine in term of its capability in generating voltage. In experimental test, it can be obtained that the double Savonius Turbine could effectively generate 12V at 3 m/s and 17V at 5.4 m/s. Keywords— Double Turbine; Savonius and Wind Turbine


I. Introduction
Wind energy is one of clean, friendly to environment energy sources, abundantly available naturally and free to use for energy [1].The application of wind as source of energy is started since long time ago.It was recorded that wind had been used for sail at Nil river since 5000 BC.Application on other purposes such as drilling had been introduced in Persia, Egypt and China in 7 Century and its application as electric power source was boomed at the beginning of 19 th century in Europe [2].
According to [3], wind characteristic in Indonesia varies from 2.7-4.5 m/s where it is categorized as low wind speed with common turbulence.One of wind turbine type is Vertical Wind Turbine (VWT), where the main rotor is located perpendicularly.The main advantage of VWT is that no vane or tail is required to direct the turbine on wind direction.This function is very suitable for the area where the wind direction is changing rapidly.One of VWT turbine that is well known widely is Savonius.This wind turbine type is The application of wind as source of energy is started since long time ago.It was recorded that wind had been used for sail at Nil river since 5000 BC.Application on other purposes such as drilling had been introduced in Persia, Egypt and China in 7 th Century and its application as electric power source was ury in Europe [2].

A. M. Shiddiq Yunus
], wind characteristic in Indonesia 4.5 m/s where it is categorized as low wind speed with common turbulence.One of wind turbine type is Vertical Wind Turbine (VWT), where the ly.The main advantage of VWT is that no vane or tail is required to direct the turbine on wind direction.This function is very suitable for the area where the wind direction is changing rapidly.One of VWT turbine that is well ius.This wind turbine type is applicable on low speed wind because it could produce sufficient torque [4].To improve the capability of Savonius in extracting energy from the wind, double Savonius is introduced in this paper to investigate the performance of the turbine in generating voltage.Typical model of Savonius is shown in Figure

A. Location and Research Time
The data was collected at Tanjung Merdeka Beach, Tamalate District, Makassar, Indonesia.The data was collected from 27 th to 30 th September 2015, started from 08.30 to 18.30 Center Time of Indonesia (CTI).

Research Methodology
The data was collected at Tanjung Merdeka Beach, Tamalate District, Makassar, Indonesia.The data was September 2015, started from 08.30 to 18.30 Center Time of Indonesia (CTI).

B. Double Savonius Design
The stage of design can be seen in Figure 2. layout of double Savonius is shown in Figure 3

III. Results and Discussion
The dimension of the designed double Savonius can be described in Table 1.Table 2 shows the performance of the double Savonius in terms of generated voltage in accordance to wind speed.
The performance of the testing stage of the double Savonius can be seen in Figure 5 to 9. It can be seen from Figure 5 to 9 that when wind speed increased, the other parameters are also raised gradually.It was measured that starting point of this double Savonius could generate voltage is 3 m/s and resulting about 12V whilst the maximum voltage could be generate is 17V at the wind speed of 5.4 m/s.The small fluctuation occurs due to the fact that data was taken per hour and not in continuous ways.It can be seen in Table 2 that some wind speed values have the same values but in rpm measurement come with small differences.This occurs due to the fact that wind speed intermittently influences the starting torque of the double Savonius.
For simplicity of analysis, data that was collected in 4 days is sorted from the lowest to the highest wind speed.

IV. Conclusion
From the testing results, it can be concluded that double Savonius could generate about minimum 12V at speed of 3.0 m/s and maximum 17 Volt at 5.4 m/s.With minimum 12V of charging voltage it is sufficient to charge an accu after rectifying.

Figure 4 .
Figure 4. Real construction of

 Figure 5 .
Figure 6.Trend of per-phase vs generator speed

Table 1 .
Dimension Information of Designed Turbine