• Energy Research
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Global warming has become an increasingly important issue around the world today due to the rise of anthropogenic greenhouse gases emission, which gives several negative impacts on human life. There are some techniques have been studied and assessed i.e. physical mechanism by injected CO2 to the geological formations, chemical mechanism with artificial tree technology and biological mechanism by increasing the primary production through iron enrichment in high nutrient-low chlorophyll (HNLC) waters as well as mixing of water column below the sea surface. Those technologies, which are well known as Carbon Capture Storage ‘(CCS) technology, are expected to be applied to reduce the oncentration of anthropogenic CO2 in the atmosphere and to minimize the global warming. The Center of Environmental Technology, Agency for the Assessment and Application of Technology (BPPT) will carry out a research concerning CO2 reduction by a phytoplankton culture in a photobioreactor in three years. The main objective of this research is to assess the CO2 uptake capability of tropical phytoplankton. In this paper, we would showed the creteria and design to assembly a photobioreactor esspesially a air lift photobioreactor. To improve performance photobioreaktor, the materials included design criteria and the dynamics of fluids in fotobioreaktor have to considered propoerly. Other the hand, the selection of the most productive species and selection of appropriate media and economically also important to be done.

- Source of electrical energy is currently the main problems in Singkawang city, this is because the number of population density increased annually. Besides, the problem of the amount of waste continues to rise, these two problems can be solved with one solution to convert a renewable energy that makes a potential where trash converted into power plant of waste to energy. To determine whether the waste can be a solution to the energy crisis by conducting a study of potential waste or garbage into fuel power plant. writing this essay described how rubbish can produce electrical energy for 24833.76 kWh / day if operating for one year amounted to 9,064,322.4 kWh / year or 9064.32 MWh / year, The first step is to know the total amount of organic waste per day, the number of calories in the organic waste, the amount of energy (kWh) / day, the capacity of power generation, the power output of the boiler, steam turbine net power.

The first use of microalgae by humans as food detected in the dates back 2000 years, but the development ofbiotechnology of microalgae just began in the middle of this century. Microalgae refer to biomass resourcecontain many useful components such as protein, carbohydrate, fatty acid, etc. Products based microalgae arediverse from human food and nutrition, animal feed and nutrition up to fine chemicals such as triglycerideswhich is able to be converted to biodiesel. Microalgae is a promising biomass resources, (i) microalgae isrenewable resources which has high biodiversity properties, (ii) production cost of converting process frommicroalgae biomass into its derivatives relatively low, (iii) product derivatives of microalgae have a highdemand in market. Based on above, microalgae can be developed further to be applied as raw material for food,energy and pharmacy. This paper described microalgae in general and the developing technology used toproduce commercial microalgae based product.

Various scientific studies illustrate that carbon dioxide (CO2) in the atmosphere layer that is a consequence of the result of the combustion of coal, timber, oil and gas, has increased by almost nearing 20 % since the start of the industrial revolution. Industrial area are built almost in the entire continent of the world has resulted in waste of “Greenhouse Gases (GHG) such as carbon dioxide (CO2), methane (CH4) and nitrousoksida (N2O) that caused the blanket effect. The purpose of this research was to detect the presence or absence of climate change and determine the projected climate change due to global warming. This research was conducted in the city of Palu, Central Sulawesi, using daily data and analyzed on a daily, monthly and yearly. Trend projections of climate change and changes in the method of analysis Makesens (Mann - Kendall and Sen 'S). The conclusion of this research is the change of climate in the city of Palu is characterized by slowly increasing temperature , increased precipitation and decreased evapotranspiration and the results of the calculation value of Z indicates Makesens method occurs climate trend, either positive direction (increasing) and negative (decreasing). Regression equation projected annual average temperature (as an example) is; f (year) = 0.018 (year - first year) + 26.931.

The issue of energy is a global issue that must be discussed by all countries in the world. Rising oil prices and a dwindling supply push every country to develop new renewable energy alternatives. One of this alternative energy is biodiesel. The biodiesel production can be done by using vegetable oil as the raw material over supported homogeneous catalyst, heterogeneous catalyst and enzymatic catalyst. In this study the use of palm oil as the main material to be reacted with methanol and the catalyst used as heterogeneous catalysts SO42-/ZnO by changing variables used are long reaction times (1, 2.5 and 4 hours) and the weight ratio of catalyst / oil (4 , 6, and 8).The studybeganwith thepreparation of catalyst SO42-/ZnO followed by aransesterification reaction between palm oil with methanol. The resultsofthis studyshowed that the super acid catalyst SO42-/ZnOcan be usedin making biodiesel.Optimum operatingcondition for this catalytic reaction is the weight ratio of catalyst/oil 3,8 during 2,5 hours with 78% yield of the resulting ester metal.Longer time ofthe transesterificationreaction, the higher the % yield ofthe resulting ester metal, while adding more catalyst produced the lower theyield.

The modeling of the wind speed distribution is of great importance for the assessment of wind energy potential and the performance of wind energy conversion system. In this paper, the choice of two determination methods of Weibull parameters shows theirs influences on the Weibull distribution performances. Because of important calm winds on the site of Ngaoundere airport, we characterize the wind potential using the approach of Weibull distribution with parameters which are determined by the modified maximum likelihood method. This approach is compared to the Weibull distribution with parameters which are determined by the maximum likelihood method and the hybrid distribution which is recommended for wind potential assessment of sites having nonzero probability of calm. Using data provided by the ASECNA Weather Service (Agency for the Safety of Air Navigation in Africa and Madagascar), we evaluate the goodness of fit of the various fitted distributions to the wind speed data using the Q – Q plots, the Pearson's coefficient of correlation, the mean wind speed, the mean square error, the energy density and its relative error. It appears from the results that the accuracy of the Weibull distribution with parameters which are determined by the modified maximum likelihood method is higher than others. Then, this approach is used to estimate the monthly and annual energy productions of the site of the Ngaoundere airport. The most energy contribution is made in March with 255.7 MWh. It also appears from the results that a wind turbine generator installed on this particular site could not work for at least a half of the time because of higher frequency of calm. For this kind of sites, the modified maximum likelihood method proposed by Seguro and Lambert in 2000 is one of the best methods which can be used to determinate the Weibull parameters.

In Bahasa Indonesia : Kendaraan bermotor yang merupakan alat transportasi yang sangat dibutuhkan oleh masyarakat di negara-negara modern, menimbulkan masalah besar terhadap lingkungan dan akibat polusinya sudah sangat terasa, terutama di kota-kota besar. Untuk menanggulangi masalah ini, maka sejak pertengahan abad 20 telah banyak dilakukan tindakan-tindakan yang bertujuan mengurangi atau melenyapkan pengaruh gas yang ditimbulkan oleh motor bakar. Sejak akhir abad 20 telah mulai dikembangkan alat untuk menggantikan motor bakar yang ternyata mempunyai beberapa keuntungan yang sangat menonjol, yaitu fuel cell yang dapat menghasilkan energi melalui proses elektro kimiawi. Berhubung fuel cell sangat berbeda dari motor bakar, maka kendaraan yang menggunakannya mengalami Perubahan komponen yang cukup radikal diantaranya sistem bahan bakar, sistem penerus energi dan sistem kontrol. Dari hasil pengembangan dan penelitian yang telah dilakukan ternyata jenis fuel cell ini sangat menjanjikan keuntungan-keuntungan yang tidak dimiliki oleh motor bakar, sehingga bukanlah hal yang mustahil bahwa fuel cell akan menggantikan motor bakar. Kata kunci: otomotif, fuel cell, polusi. Cars powered by engine is one of transport vehicle used in developed countries, which caused ecological problem to the environment, the effect of this problem is faced nowadays especially in big cities. Since medio of 20th century many researches and developments have been done, to cope with that problem, to have less emission in the environment. One of the equipment to replace engines, have been developed since the last decade of 20th century, give a lot of advantages called fuel cell, which can produce energy by electric-chemically process. Due to the differences of fuel cell compare with conventional engine, vehicles using fuel cell has to be redesign, some components have to be changed radically, like the fuel system, drive train and control system. The result of researches and developments which have been done, promise a lot of advantages, which conventional engines can not give, therefore it is probable that fuel cell will replace conventional engine.

Limitations of diesel which is a non-renewable energy sources, requires alternative fuels to renewable and environmentally friendly, for example is biodiesel. The main reaction is the production of biodiesel esterification and transesterification, but these conventional reactions are slow, requires a lot of alcohol and a catalyst, the reaction has not been perfect, and the products do not meet SNI and ASTM standards. In this research, mixing castor oil and palm oil as biodiesel feedstock, but it aims to obtain the optimum conditions for the blending ratio variable mass castor and palm oil, the amount of catalyst to oil, and the mole ratio of methanol-oil with helped by ultrasonic waves. The resulting biodiesel product is expected to meet SNI and ASTM standards. The main tool used is the ultrasonic cleaner. Variable that is the ratio of the mass of castor oil and palm 1:1, 2:1, and 3:1, the amount of catalyst KOH 1%, 1.5%, and 2% by mass of oil, and methanol-oil mole ratio 3:1, 6 : 1, and 9:1. The results obtained highest conversion achieved in the mass ratio 2:1 castor oil and palm oil, catalyst 1.5% by mass of oil, and the mole ratio of 6:1 with a mixture of methanol-conversion 95.341% where diesel fuel product meets SNI and ASTM standards.

Bioethanol is one type of biofuel that developed significantly. The utilization of bioethanol is not only limited for fuel, but also could be used as material for various industries such as pharmaceuticals, cosmetics, and food. With wide utilization and relatively simple production technology has made bioethanol as the most favored biofuel currently. The use of lignocellulosic biomass, microalgae, seaweeds, even GMO (Genetically modified organisms) as substrates for bioethanol production has been widely tested. Differences in the materials eventually led to change in the production technology used. Pretreatment technology in the bioethanol production using lignocellulosic currently experiencing rapid development. It is a key process and crucial for the whole next steps. Based on the advantages and disadvantages from all methods, steam explotion and liquid hot water methods are the most promising pretreatment technology available.

Energy and exergy analysis has been conducted on photovoltaic (PV) system in Bantul Regency, a special region of Yogyakarta, Indonesia. The PV exergy analysis was used to determine the performance of the PV system by considering environmental factors other than solar irradiance. This research aims to obtain values of exergy and energy efficiencies in the PV system. The experiment results show that the energy efficiency value produced by the PV system was 8.62–74.18%, meanwhile its exergy efficiency was 0.29%-9.40%, respectively. The value of exergy efficiency is lower than the value of energy efficiency. This result confirmed that the environmental factor greatly affects the output of the PV system. It can be concluded that high solar radiation does not always increase the production of exergy, since it is also influenced by the environmental temperature and the PV cells' temperature.