IPTEK The Journal of Engineering
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The Effect of Feedwater Heaters Operation Schemes to a 200 MW Steam Power Plant Heat Rate Using Cycle-Tempo Software
Get PDFThere are several ways to improve performance of Rankine cycle which is implemented at steam power plant, regenerative feedwater heating is one of the methods. Some failures in closed feedwater heaters such as, water leak through manhole and tube leakage may happen during operation of the plant. Repairing such failures may take some period of time and must shut off the operation of the feedwater heaters. Further study is needed to evaluate the effect of closed feedwater heater in off-service condition against the steam power plant’s performance. This study varies off-service condition of closed feedwater heaters applying thermodynamics analysis and modeled through Cycle-Tempo software. There are 12 possible feedwater heater operation schemes. Based on the heat balance and equipment design of a 200 MW Steam Power Plant at Jakarta-Indonesia, this study concluded that the NPHR might increase as much as 0.96% and 0.39% due to the off-service of any HPH and the off-service of any LPH respectively. Schemes of 2 off-service feedwater heaters summed up with 1.37% increase of NPHR
Energy Auditing at Block 1 Muara Karang Combined Cycle Power Plant
Get PDFEvery year electricity growth in the world always increases. But the growing growth is the need for future controls in order to make the utilization more effective and efficient. In addition, with the utilization of appropriate energy will have an impact on the preservation of the surrounding environment. In Indonesia, has been regulated related to the efficient utilization of energy by the enactment of Government Regulation No 70 of 2009 of Energy Conservation. The method used for this research is to conduct an energy audit on PLTGU Block 1 Combined Cycle Power Plant (CCPP) Muara Karang. This audit is begin from collecting operating parameters’ data then conducting the performance calculation of the main equipment. The result of the calculation then compared with commissioning data in 1995. From the calculation obtained the profile of energy use and find the largest gap from the comparison between actual performance with commissioning in 1995. The gap is then analyzed the cause of equipment inefficiency and conducted field study. After that is given the recommendation of Energy Saving Potential to be able to improve the efficiency of the equipment. The recommendations are analyzed by economic studies to provide alternative improvements solution for management
Searching the Correct and Appropriate Deterrence Function General Formula for Calculating Gravity Trip Distribution Model
Get PDFTrip Distribution Model is a very important part of Transport Modeling. This is a result of a mathematical operation among Trip Generation, Generalized Cost Matrix, and Deterrence Function. Thus, it can be understood easily that having a correct and appropriate Deterrence Function Formula is important. Here, correct means that the curve form is in concordance with typical Trip Length Distribution pattern. While, appropriate means that the function is easy to be manipulated in getting a good conformity with the Trip Length Distribution. Three Deterrence Function types, i.e. negative power, negative exponential, and Tanner, were investigated. The investigation was done upon Negative Power Function, Negative Exponential Function and 4 combinations of Tanner Function. The research result indicates that the Negative Power and the Negative Exponential are correct. While, among the four Tanner Function combinations, the correct ones are only the Tanner Function – Negative Power Negative Exponential and the Tanner Function – Positive Power Negative Exponential. The correct and appropriate Deterrence Functions are the above four Basic Functions multiply by a Constant
Study of Shipboard Power Distribution System: Review on an Aplication of AC Zonal Distribution
Get PDFThe shipboard power distribution system has been developed in order to make it more efficient. AC zonal distribution system is one of the options in order to achieve the objection. This study aims to observe the shipboard application with AC zonal distribution system. The distribution system is modeled, simulated, analyzed, and compared with conventional system. Based on simulation, the AC zonal distribution system provide higher reliability, better power continuity, and more stable power generation. Therefore, development of the zonal distribution system continues to bring succeed in every mission. However, the system has several challenges for future work such as more complex transmission system, higher voltage drops, and the tendency to have instability power distribution when one generator fails
Behavior of Trip Length Distribution Pattern due to the Variation of Trip Length Interval Determination
Get PDFTransport Model is always needed and important for developing Transportation System Master Plan. Trip Distribution is one of the important parts of Transport Model, which is a result mathematical operation of trip generation and deterrence function. Trip Length Distribution Pattern is the foundation of Deterrence Function. The trip length distribution pattern can change due to the various trip length interval used. Analog to this, the Deterrence Function can also change. The research result indicate that the distribution pattern change significantly on trip length interval 1 to 3 km. For trip length interval of 4 to 8 km, the trip length distribution indicate the general characteristic of trip length distribution, i.e. the number of trips is high in short distance and getting down in the longer trip distance. The trip interval of 7 km gives the most accepted Tanner Deterrence Function
Effect of Holding Time and Cooling Medium on Microstructure and Hardness of AISI 8655 in Hardening Process
Get PDFThe microstructure transformation of AISI 8655, affecting to hardness and impact properties in various hardening processes, has been investigated in this work. AISI 8655 specimens which had been prepared before hardening processes were heated to austenite temperature and held for 30 minutes and 60 minutes then continued by rapid cooling in various medium (air, oil and water). The hardened steel specimens were tested by optical microscope to observe microstructure, brinell test and impact test respectively to measure hardness and impact strength properties. Martensite and bainite were microstructures that appeared after hardening processes. The holding time for 30 minutes gave higher hardness properties than the holding time for 60 minutes. However, the holding time for 60 minutes performed higher impact strength than that for 30 minutes. The highest of hardness was performed by the specimen cooled in water medium at 552 BHN and the highest of impact strength was performed by the specimen cooled in air medium at 7.2 J/mm2
NPV at Risk Review on Investment Evaluation of Hotel Development in Block M Jakarta
Get PDFHotel Grandhika Blok M Jakarta built in 2013 and started operation in early 2016. In terms of investment, the function of the building is not necessarily the best. Therefore it is necessary to do further study on the evaluation of hotel development, whether it remains operational as a hotel or there is a better investment alternative on the land of Grandhika Hotel Block M. The results of spreading questionnaires to five property experts consisting of academic and practitioners experts, are obtained the probability for hotel 100% optimists and 0% pesimists, Apartement 60% optimists and 40% pesimists, Offices 40% optimists and 60% pesimists. Then do the calculation Net Present Value (NPV). From NPV analysis obtained value NPV after 8 years for hotel NPV Rp. 7,788,146,628.49 , apartments NPVRp. 17,992,955,784.81 and officeNPV Rp. 6,852,663,146.56. For a maximum productivity analysis of the value of the property at the end of the investment period, so the utilization of land for the hotel will provide productivity of76.90%, for apartements provide productivity of 41.62% and office provide value of productivity of 18.16%. After obtained probability, productivity analysis and Net Present Value then taken decision by using decision tree method. The result is that the hotel as the best investment. From these results the best investment the investor can decide whether to continue operating the hotel or change functions the best alternative of the existing alternatives
Influence Of The Compression Ratio And Ignition Timing On CB150R Engine Performance With 85% Bioethanol gasoline Blended Fuel
Get PDFSubtitution of the fuel type in the gasoline engine will change the setting The engine parameters as well as modify it to minimize engine performance degradation And increased exhaust emissions. Utilization of ethanol (85% vol.) - gasoline (15% vol.) The combination (E-85) for the gasoline engine requires some machine modifications and setting parameters due to differences in properties and characters between ethanol and gasoline. This study aims to test the effect of ignition timing and compression ratio on the performance of the engine and emission gas emissions. Ignition time varies between 16-24 Before Top Dead Center (BTDC) d. While the compression ratio variation consists of 11 (standart); 12, 12.5 and 13: 1. It was found that advancing the ignition time range 16o-24o BDTC with 13: 1 compression ratio can increase the performance of torque, bmep, and thermal efficiency respectively 7.94%, 5, 82% and 1.6% respectively, and a decrease of emissions of co and hc respectively 56.6% and 0.6% when compared with the performance of standard gasoline-fueled engines (E0)
Variability of Sea Surface Temperature in Indonesia Based on Aqua Modis Satellite Data
Get PDFSea surface temperature (SST) is one of the oceanographic factor in seawater. Its value depends on several factors. In indonesia, SST value depend on season and location. The aims of this study are to analyze the spatial and temporal variability of SST using 10-years (2007-2016) Aqua Modis satellite data. The result shows that the average of SST in Indonesia ranges from 27 – 31 °C depending on location. SST in equator area range from 30 – 31 °C and in nonequator area range from 27 – 30 °C. Monthly and seasonal variation of SST also show different value for each area in the indonesian region
Developing Citizen Relationship Management (CiRM) Oriented E-Government Maturity Model
Get PDFCiRM (Citizen Relationship Management) has an important role in the government because it puts citizen in the best interests. So far the implementation of e-government only focused on the technology assimilation process. Since existing e-government maturity assessment models only measure the ability of e-government technology, they lack in consideration towards citizen needs. Therefore an e-government maturity assessment model is developed by incorporating elements of CiRM. The model was developed through a grounded theory qualitative study approach. The object of this research is e-government application owned by the city of Surabaya. This research developed CiRM oriented e-government maturity model consisted of organization, interaction, service and citizen insight dimensions. This model then was used to assess the maturity of CiRM oriented e-government implementation of Surabaya Single Window (SSW) online servic