WIND TURBINE VERTICAL AXIS H ROTOR TYPE WITH 1 kW CAPACITY AT SUWUK BEACH, KEBUMEN

Abstrak : Tulisan ini membahas tentang analisa potensi energi angin di pantai Suwuk Kebumen dan perancangan turbin angin tipe H-Rotor yang sesuai dengan karakteristik angin di pantai tersebut. Analisa potensi energi angin menggunakan metode distribusi Weibull berdasarkan data kecepatan angin di lokasi pengukuran selama 2 tahun. Analisa distribusi Weibull menunjukkan karakteristik kecepatan angin di lokasi pengukuran yang akan dijadikan dasar dalam perancangan turbin angin H-Rotor. Perancangan turbin angin H-Rotor terdiri dari komponen-komponen seperti sudu, strut, dudukan strut, poros, tiang, dan generator. Diperoleh rancangan turbin angin H-Rotor dengan diameter x tinggi sebesar 2,7 x 2,7 meter menggunakan airfoil tipe NACA 0018 dengan kapasitas daya keluaran sebesar 1 kW..


PENDAHULUAN
In recent years, the energy crisis that hit the world and particularly in Indonesia became a problem which is quite crucial. The fuel needs of human life is increasing, while supplies of oil or gas is very limited and can not be renewed cause oil reserves from year to year decrease dramatically.
It can be seen from the data above that oil production declining in Indonesia from year to year and 163.633 thousand barrel of crude oil production was down 50% from the previous year by 2012. In addition, due to the pollution, the global warming has been arising from the burning of fossil energy sources. It made us to enterprise for alternative energy sources that are clean and not limited to generating electricity.
Indonesia is a country with energy resources are very abundant, one of them are water and wind energy sources. Indonesia is an archipelago and one of the countries which located at the equator to be one factor why Indonesia has an overflow wind energy feasible. Its potential is quite adequate, due to 3.5 to 7 m/ s of the average wind speed ranges in Indonesia. The mapping of National Institute of Aeronautics and Space (LAPAN) at 120 locations shows some regions have wind speeds above 5 m/ sec, East Nusa Tenggara, West Nusa Tenggara, South Sulawesi, the southern coast of Java, respectively. The wind power applications as a source of renewable energy in Indonesia is very likely to be further developed [1].
The southern coast of Java has wind energy potential is tremendous with 3.5 to 7 m/ s of the average wind speed ranges. The suwuk beach become one of southern coast of Java is located in the southern city of Kebumen and used as tourist attractions. As a tourist attraction, the suwuk beach requires a supply of electrical energy among others for food stall lighting, drain the water, and the fulfillment of electricity at some recreation places.
The electrical energy source on this coast is originate from PLN and only available on a small scale by this time. In addition, the power outages is frequently happen which caused electricity shortages at Suwuk beach. Therefore, we need another energy source to overcome an electricity. A large number of wind energy potentials on Suwuk beach made wind turbine is the right choice to tackle the problem.

RESEARCH METHODOLOGY
The H-rotor wind turbine design begins with wind speed data processing by using Weibull distribution method. The Pandansimo Bantul beach wind speed data was used due to its complete and located in the same geographic of suwuk beach which placed the south coast of Java island. Data has been obtained by measuring wind speeds at the beach Pandansimo for two years from June 2013 to 2015. It was found that wind speed often arise (VF) 4.37 m/ s of wind speed while carrying 7.99 m/ s of maximum energy (VE). Based on its characteristics, calculation and determination of each component Hrotor wind turbine models can be done.

RESULT AND DISCUSSION Wind Speed Data Processing
The wind speed data processing results was obtained during the two years from June 2013 to June 2015 by using the graphs and cumulative probability density of Weibull distribution [2], as shown in Figure 1 and Figure 2.  Figure 1 that often frequently appears 4.37 m/ s of wind speed with 14%. Figure 2 shows the wind speed appearance chance at certain intervals. The cut-in wind speed is equal to or greater than 2 m/ s, 3 m/ s and 94.24%, 84.8% respectively.

The H-Rotor Wind Turbine Design
Hybrid turbine construction is shown in Figure  1. The components that will be constructed are blade, strut, strut mounting, shaft, mast, generator and Swept area ( A ) = 7.29 m 2 2. Force Analysis on Blade The aerodynamics H-rotor analysis is quite complex though the rotor shape is relatively simple. As the wind strikes the blade, not only wind speed are affecting lift (L) and propulsive force (D) on the blade but also influence the relative wind speed [3].
Lift (L) is a force that perpendicular to the relative wind speed while the thrust (D) is a force that parallel to the relative wind speed. Normal force (N) is a force that is perpendicular to the chord of the blade while the axial force (A) is a force that is parallel to the chord of the blade as shown in    Width (b) strut is 60 mm, since there will be screw mounted to a strut, then the size of the thickness (h) strut to: Bending compressive stress due to the weight of the turbine blade a. = √ = 54,55 mm b. Press tension due to sentrifugal force h = From the calculations above, the resulting voltage was on below of the maximum allowable stress design that was 27.57 MPa. It can be concluded that the size of the strut with a width x height of 60 x 12 mm it was safe to use.

Generator
Generators were used in the wind turbine design was a permanent magnet generator which is capable of producing 1000 watts at 450 rpm of rotation. These generators were imported from Ginlong Manufacturer, an electric generator factory, PMG types.
= 39,05 mm then it was selected thick strut holder (h) of 39.05 mm. b. Strut The strut material was the same as the material for the holder strut. Strut was tensioned a bending pressure due to turbine heavy blade and compressive stress due to centrifugal force [6]. Number strut for each blade was 2 [7].   Table 3 shows the specifications of generator GL-PMG-1000. It can be seen that the rated rotation speed of 450 rpm to produce a power output of 1000 watts.
Tabel 3. Spesifikasi GL-PMG-1000 6. Transmision From Table 3, the generator rated rotation in order to produce an output power of 1 kW is 450 rpm while the axis wind turbines rotation only at 233 rpm. Therefore, it is necessary to raise the transmission shaft rotation. Transmission used was a bevel gear as shown in Figure 4:20.

Shaft
The main shaft will be reinforced using a hollow shaft which also will become a pillar of the wind turbine. In addition, this pillar also serves to put the taper bearing on the end of a pole. Calculation of shaft diameter of hybrid vertical axis wind turbine the axis type of the twisting moment (Te) and bending moment (Me).