8 9
2.9 Penyimpanan Biogas
Biogas dapat disimpan seperti halnya gas LPG dalam tabung gas. Proses penyimpanan ini dapat dilakukan dengan mesin kompresor. Biogas dihisap dan dikompresikan dalam tabung
botling . Beberapa hal yang menjadi pertimbangan adalah, biogas mengandung gas H
2
S yang sangat korosif terhadap tabung gas terbuat dari baja. Langkah-langkah pencegahan korosi harus
dilakukan baik dengan menurunkan kadar H
2
S terlebih dahulu sebelum disimpan, maupun mengunakan tabung penyimpan dari bahan yang lebih tahan korosi.
2.10 Pengujian komposisi biogas dan Pengukuran Volume Biogas
Komposisi biogas harus diuji sehingga diketahu berapa komposisi gas metana yang dihasilkan. Grup riset industri manufaktur dan permesinan memiliki kelengkapan alat untuk
menguji secara langsung dilapangan berapa kadar gas metana, CO
2
, H
2
S, dan kandungan air yang terkandung dalam biogas. Gambar 12a adalah beberapa dari peralatan pengujian gas
portabel yang siap digunakan untuk menguji langsung di lokasi digester. Alat ini juga mampu mendeteksi adanya kebocoran gas dalam instalasi biogas sehingga kebakaran dapat dihindari.
Pengukuran volume amat penting baik untuk mengukur laju aliran dan juga untuk mengukur jumlah biogas yang dihasilkan atau jumlah volume biogas yang dihasilkan. Alat ukur volume
meter seperti tampak pada Gambar 11b sudah tersedia pada grup riset kami.
3. Kesimpulan
Penelitian kearah penelitian dan pengembangan teknologi biogas di Universitas Udayana, Bali, Indonesia telah menghasilkan berbagai temuan yang bermanfaat pagi perkembangan teknologi
biogas maju advance biogas technology . Hasil temuan ini memungkinkan pemanfaatan biogas
untuk pemakaian yang lebih bermanfaat seperti untuk menghasilkan listrik dan penggerak mesin. Teknologi pemurnian biogas menghasilkan produk yang lebih bebas dari pengotor-pengotor yang
berbahaya bagi kesehatan
4. Ucapan Terimakasih
Tulisan ini merupakan akumulasi hasil dari berbagai penelitian yang dihasilkan dari beberapa berbagai hibah penelitian seperti hibah Pengajaran dana DIPA Univ udayan 2012, hibah bantuan
seminar luar negri Dikti 2012, hibah penelitian strategis nasional Dikti 2012, hibah penelitian berpotensi paten 2012, hibah bersaing Dikti 2013. Untuk itu terimakasih penulis sampaikan atas
pembiayaan penelitian yang diperoleh dari hibah-hibah penelitian tersebut di atas
Gambar 12. a. Berbagai alat ukur komposisi biogas portabel yang sudah dimilikivgrup riset kami
[6] . b. Alat ukur volume biogas [6]
a b
5. References
[1] Nindhia, T.G.T., 2012, Equipment to increase rate of Biogas Production by Utilizing solar Energy, Paten Id, No paten: S 0001154
[2] Nindhia, TGT, Negara, K.M.T.N., Sucipta, I M., Surata, I W., Atmika, I K.A., Negara, D.N.K.P, 2012, Performance of Repetitive type of Biogas Desulfurizer Made from Steel Chips Waste,
Proceeding of The 2
nd
International conference sustainable technology development, 4-5 Oktober ,Bali, Indonesia
[3] Nindhia, TGT, 2012, Removal of Hydrogen Sulide H
2
S contaminant in Biogas by Utilizing Solid Waste Steel Chips from The Process of Turning, The 21
st
Internatioanal Conference on Solid Waste Technology and Management, Philadelphia, PA U.S.A. March 11-14, 2012
[4] Nindhia, TGT, Negara, KMT, Sucipta, IM, Surata, IW, Atmika, IKA, Negara DNKP, Performance of Repetitive Type of Biogas Desulfurizer Made from Steel Chips Waste, Proceeding od the 2
nd
International Conference on Sustainable Technology Development ICSTD, October 31st 2012, Bali, ISBN 978-602-7776-06-7, udayana university press. pp M63-M69
[5] Negara, K.M.T., Nindhia, T.G.T., Sucipta, M., Atmika, K.A., Negara, D.N.K., Surata, W., and Komaladewi, A.A.I.S., 2012, Puriication Biogas forms H2S impurities by utilizing Waste of
Iron Chips obtained from turning process.Jurnal Energi dan manufaktur, Vol.1 No. 1, pp33-34, October
[6] Nindhia, T.G.T, Sucipta, M., Surata, I W., Atmika, I K.A., Negara, D.N.K., Negara, K.M.T., 2013, Processing of Steel Chips Waste for Regenerative Type of Biogas Desulfurizer,
International Journal of Renewable energy Research, Vol.3, No.1, January. [7] Nindhia,T.G.T., Surata,I W., Atmika, I K.A., Negara, D.N.K.P., Wardana, A.,Method on
Conversion of Gasoline to Biogas Fueled Single Cylinder of Four Stroke Engine of Electric Generator, International Journal of Environment science and Development, Vol. 4, No. 3, June
2013. pp.300-303I.
10 11
An Experimental To Investigate The Effect Nozzle Angle An Position Of Water Turbine For Obtaining Highest Rotation
Lie Jasa
1
, IGA Raka Agung
1
, I Putu Ardana
1
, Ardyono Priyadi
2
and Mauridhi Hery Purnomo
2 1
Electrical Engineering Department,Udayana University, Bali, Indonesia
2
Electrical Engineering Department, Sepuluh Nopember Institute of Technology, Surabaya, Indonesia E-mail : liejasaunud.ac.id
Abstract
Water is a key issue for an alternative renewable energy source has environmentally friendly and very large potential to solve the world’s energy crisis. Water energy can be converted into mechanical energy by means a
micro-hydro turbine. Therefore, the speciic turbine is required to obtain the highest eficiency. This paper proposes the experimental to investigate the signiicant parameters for obtaining the highest eficiency turbine. These
parameters, angle and position nozzle, radius, blades and rotation, are investigated by conducting experiments using mini turbine models. The angle and position nozzle is adjustable to obtain the highest speed rotation of
turbine. The characteristics of the mini turbine model are explained as follows: outer radius is 0.5 m, inner radius is 0.4 m, width 0.12 m, the number of blades 32, volume 0.294 litre blades. The experiment result shows that the
highest rotation is obtained by 10 degrees for nozzle position and 35 degrees for incidence angle. The best position of nozzle at blades number 2 produces the speed of turbine 68.31666667 rpm.
Keywords : Nozzle, turbine, water wheel, energy
1. Introduction
The energy plays an important role for population in the world. The energy demand is signiicantly increases every year but the energy resource is limited and decreases especially conventional
energy. Hydropower is one of clean energy resources in the world. It is also the most reliable and effectively cost renewable energy resource among the others. Small hydropower schemes are getting
increasingly popular because of its simplicity design, ease in operation, and lower environment of heavy construction in comparison to large hydropower schemes[1]. Conventional highly eficient
low head hydraulic turbines, such as Kaplan, become economically unviable because of the large size of the turbine required for very low head installations, requirement of special low control
mechanism and the risk the impose on the ecology especially on ish, trash and sediment transport. [1],[2],[3].
Water wheel is a simple machine, cheap and has long been known in the community to generate the energy. Water wheels were used as a primary source of power in ancient times. Water wheels
are simple machines usually made of wood or steel with blades ixed at regular interval around their circumference. The blades are pushed by the water tangentially around the wheel. The thrust
produced by the water on the blades produces torque on the shaft and as result the wheel revolves. [1],[4],[5]. Four commonly used water wheels models are overshot, undershot, breast shot and
stream wheels. Overshot waterwheels are driven by potential energy created by the accumulated
water in the buckets of the wheel. Water lows at the top of the wheel and ills into the buckets attached on the periphery of the wheel.[1],[6],[7],[8],[9].
Research shows that turbine are technically and eficiency of 75-85 over a wide range of low. Slow speed of rotation and large sized cells of the water wheel reduce the risk to aquatic life
as well as allow better sediment transport and tolerance to loating debris.[1],[3]. Previous research on the turbine was intended to design micro-hydro turbines to produce electricity. In this present
study, the researcher uses a micro-hydro plant in the village of Gambuk, Pupuan, Tabanan, Bali- Indonesia as the initial model of the experiment [10],[11],[12]. In this paper proposed how to get the
maximum RPM of water wheels based on the inluenced of the position nozzle and the incidence nozzle.
2 The overshot water wheel model
2.1. Hydraulics power theory
Theorem of water low is used to determine the amount of energy that can be generated from the lowing water. The total extractable hydraulic power from the lowing water is given
by the expression of P
in
= ρ x g x Q x H, where Pin is the hydraulic power input to the wheels W, ρ is the density of water kgm
3
, g is the acceleration due to gravity 9,81ms
2
, Q is the volumetric water low rate m
3
s and H is the difference in total energy line upstream and downstream of the wheel m. The angular velocity ω rads of the wheels is calculated from
the number of revolutions N at the given load in revolutions per minute RPM of the wheel as : ω = 2 x π x N60. The shaft torque τ Nm is the product of the force F of water striking
the blades of the water wheel N and the moment arm length m which, in this case, is the radius of the pulley r. Force is equal to the differences in the mass obtained from the two load
cells time the acceleration due to gravity. τ = m x g x r. Subsequently the mechanical power output Pout available at the wheel shaft is determined from the measured torque τ and the
corresponding angular speed of the wheel ω as : P
out
= ω x τ = 2 x π x N x τ60. by calculating the power of output and input, the mechanical eficiency η of the wheel is therefore : η = P
out
P
in
x 100
2.2 Overshot water wheel prototype
Water wheels model is created specially to variety of the nozzle position and the angle nozzle that can be adjusted mechanically. This model is different from the water wheel of real
installation. Water wheel model is planned rotating clockwise direction with 32 blades and 11.25
o
space of blades. The blades shape is triangular and placed around circumference wheel. The position of arm nozzle is variety multiples 11.25
o
and The blades of wheel are marked of numbers 1 through 17. The actually we changed the magnitude of β angle value. The arm
nozzle is made longer than the radius of wheels. The overshot water wheel consists of acrylic of cylindrical hub of 50 cm diameter and
12 wide on to which 32 triangular blades have been fastened. Blades are made of right-angle triangle with base and high size 7,5 cm. Length of nozzle 8 cm ixed on top of waterwheel. The
water that is lowing into the water wheel is supplied by Universal pump. Wheel is placed in the middle of a pair of pillow and wheels spin together with the axle. Details of the overshot water
wheel model are shown in Figure 2.
12 13
Figure 1. Overshot water wheel nozzle angle design
Figure 2. Overshot water wheel nozzle angle outline Figure 3. Overshot water wheel nozzle angle model
2.3. Nozzle angle position