V. Hindasageri*, H. Ramesh and A. Gaurav

Abstract: Ocean wave energy conversion technology is renewable and has distinct advantages over its peers. This paper presents an experimental study on the performance of Savonius rotors for the utilization of orbital motion of the fluid particles in ocean waves in shallow waters. A five vaned rotor is considered in this work and the performance is studied for different wave heights and wave time periods for a constant water depth. These input parameters are further non-dimensionalised as orbit overlap ratio and relative water depth. The output performance parameters selected for the studies were rotor speed and shaft power. These parameters are further non-dimensionalised as frequency ratio and efficiency. From the experimental results it was found that the frequency factor increases with an increase in orbit overlap ratio and an increase in ocean depth. The efficiency was found to decrease with increase in overlap ratio but increases with increase in ocean depth. Finally, from the experimental design and ANOVA using Design Expert 8.1 software, it was found that the load is the major parameter that influences the rotor output performance.

Keywords: Ocean wave, Orbital, Renewable energy, Savonius rotor.

K. Sudhakar* and M. Premalatha

Abstract: Biodiesel is a renewable fuel currently derived from vegetable oils and animal fats. One of the limiting factors for the growth of the biodiesel market is the availability and price of feedstock. Feedstock for biodiesel has to compete with the food crops for land and water. Hence, alternative feedstock’s that are not also food crops need to be found. One such renewable energy sources are microalgae. Microalgae are capable of fixing CO2 using sunlight to produce biofuel and other chemical compounds with numerous additional technological advantages. This present study highlights the concept of algal biofuel production using open raceway ponds and a closed photo bioreactor. This article addresses its current status and future prospects of biodiesel production from micro-algae.

Keywords: Biofuel; CO2 fixation; Micro algae; Photosynthetic CO2 Sequestration; Sunlight.

S.G. Bojan* and S.K. Durairaj

S. Permana

Abstract: The Geneva conference sponsored by the United Nation (UN) in 1955, “On the peaceful uses of atomic energy” was held to promote a nuclear energy utilization path only for civil or peaceful purposes. Nuclear energy is used in more than 30 countries and contributes 16% of global electricity consumption. Indonesia has been developing its own capability for nuclear science and technology since 1954 with the aim of having a nuclear industry in Indonesia. Indonesian’s experiences of operating research reactors since 1965 for preparing a new era of nuclear industry in Indonesia can be used as a basis for science and technological capabilities
for constructing its own nuclear industry. In relation to research and development (R&D) activities on nuclear science and engineering, Indonesia becomes the leading country on nuclear technology in South East Asia especially its operating experiences in nuclear research reactors. The nuclear industry, which is based on non electric application, has already been pursued such as for agriculture, medicine and hospital utilizations etc. In case of electric based utilization such as nuclear power plant (NPP), Indonesia has a plan for the first 2 NPPs to be constructed within 2010-2015 and this will be doubled by 2025 for fulfilling 4% of the nuclear electric share of the total national energy mix a long with other new and renewable energy sources.

Keywords: peaceful uses, nuclear energy, Indonesia, nuclear industry, energy mix.

P. Panichnumsin, A. Nopharatana, B. Ahring and P. Chaiprasert*

Abstract: In this study, the co-digestion of cassava pulp (CP) and pig manure (PM) in a two-phase continuously stirred tank reactor (CSTR) was examined to find the optimum CP-to-PM mixture ratio (w/w volatile solids; VS) and to evaluate the effect of phase separation on the efficiencies of solid destruction and methane production. The results showed that the highest VS removal (29%) and the greatest production of intermediates, such as volatile fatty acids and ethanol (24%) in the hydrolysis/acidification reactor were obtained using a 50:50 CP:PM ratio. Using feedstock that had a higher CP ratio, the activity of the hydrolytic/acidogenic bacteria was inhibited at approximately pH 4. In addition, the distribution of the VFA produced was shifted at approximately pH 4.5. The removal of solids and the production of methane increased in the two-phase CSTR with increasing cassava pulp ratio, up to 60% of the feedstock. The highest reduction in solids (68%) and the greatest methane yield (370 mL g^-1VS_added) were obtained using a 60:40 CP:PM ratio. Co-digestion in a two-phase CSTR reduced the solids by 14% and increased the production of methane by 36% over those obtained using a single-phase CSTR.

Keywords: Biomethanation; Cassava pulp; Mixture ratio; Pig manure; Two-phase CSTR.

A. Pribadi*, P. Wongwises, U. Humphries, A. Limsakul and A. Wangwongchai

Abstract: Diurnal rainfall variations over three sub-domains with distinct annual rainfall cycles within Indonesia have been analyzed using Tropical Rainfall Measuring Mission datasets (3B42) for the period of 2000–2009. Empirical Orthogonal Functions (EOF) analysis was used to compare spatial-temporal variability among three selected areas (A, B and C). The EOF analysis revealed that the three regions showed dominant diurnal cycles of rainfall. The diurnal cycles of the three regions were marked by different amplitudes and phases, particularly over land and oceanic regimes. Region A exhibited an afternoon peak over land and a morning peak over ocean. Region B showed an evening peak over the land and a morning peak over the ocean. While Region C exhibited an afternoon peak over the land and an early morning to noon peak over the ocean. Over coastal areas, the same midnight peak was observed for the three regions. The result of this study provides relevant information to understand the effects of island size and landsea formation on the characteristics of the diurnal rainfall variation, particularly over the Indonesian Maritime Continent.

Keywords: Diurnal cycle, rainfall, TRMM, EOF, Indonesia.

P. Kridiborworn, A. Chidthaisong*, M. Yuttitham and S. Tripetchkul

Abstract: In Yeesan, Samut Songkram Province, central Thailand, mangrove plantations (R. apiculata) have been run with the specific purpose of charcoal production for many years. In order to estimate carbon sequestration associated with such activities, field measurements of mangrove biomass and the amount of charcoal produced were carried out. The carbon emission reductions according to charcoal use was calculated based on the energy value of charcoal in replacing liquefied petroleum gas (LPG). At an age of 12 years old, when it was harvested for charcoal production, the total average above ground biomass of R. apiculata was 9.29kg/tree. The relationship between above ground biomass and diameter (DBH) and height (H) can be expressed as total biomass (ton dry matter) = 0.249x^0.79, R² = 0.97, where x represents the product of (DBH²×H). With an average plant density of 22,089 tree/ha and a carbon content of 47%, the carbon sequestration at an age of 12 years was 140.49 ton C/ha. For other ages, carbon sequestration can be estimated from the logistic growth curve, which is expressed as: Carbon stock (ton C/ha) = 141.56/(1+4.62×10³e^-1.11t), R² = 0.99, where t is the age (years) of R. apiculata. The total carbon sequestration associated with R. apiculata plantations in the whole Yeesarn area was estimated to be 51,106.72 ton C. Based on this biomass production and the charcoal conversion efficiency, about 36 ton/ha of charcoal was produced. In the scenario that this charcoal is used for energy to replace LPG, mangrove plantation and charcoal production in Yeesarn could substitute LPG of about 58TJ/year and 3,633 ton/year of CO₂ emissions could be avoided.

Keyword: Mangrove plantation, A. apiculata, charcoal production, CO₂ reduction, Fossil fuel substitution by charcoal.