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This investigation was carried out to evaluate the characteristics of a Francis water turbine. Several variations of inlet valve openings of the turbine were tested to determine the effects of changes in rotational speed of runner on turbine performance. The method used in this study was experimental measurement using a test rig installation in Diponegoro University. The results found that discharge was not change significantly with increasing speed. The torque decreases as the turbine rotational speed increases. The break horse power (BHP) and efficiency curves are nearly identical. Both BHP and efficiency increase when speed are increased until the maximum condition is reached, then from this maximum condition, as speed increase, the BHP and efficiency gradually decrease. [ABSTRACT FROM AUTHOR]

This research is addressed to investigate the characteristics of a centrifugal pump. In this work, the experiments were carried out with variations in impeller speed and at several valve openings. The measurement results show that head have the same tendency for all variations of inlet valve opening. Meanwhile for discharge and break horse power have almost the same values at low speed for both theoretical and measurement; however at higher speed there is a significant difference. Large inlet valve openings produce large discharges as well as break horse power and motor horse power. Meanwhile for the head, the inlet valve opening has no crucial effect because it produces almost the same value. [ABSTRACT FROM AUTHOR]

Onshore Processing Facilities is one of the industries engaged in natural gas processing. The total use of natural gas over the last four years tends to increase. OPF also utilizes electrical energy as secondary energy generated from GEG. Currently the condition of installed equipment such as GEG, air compressor, HVAC, and building lighting is 8 years old, so there are indications of a decrease in efficiency. Then the GEG condition which only generates electricity around 30% of its capacity is also suspected to cause low engine efficiency. Therefore, it is necessary to conduct an energy audit to determine energy use and potential savings that can be made. Based on an audit conducted by the SEC for 2022, 0.8 GJ/TOE is still relatively efficient. The Air Compressor System has an average efficiency of 78.73%, the HVAC unit has a COP value of 3.31, the lighting level of each room in the OPF building does not meet the minimum standard, which is around 125 - 450 lux, and GEG has an efficiency value of 27.2 %, which is below the design standard. Opportunities for savings that can be made are by reducing the compressor air pressure by 0.7 bar can save Rp. 21,778,565, installing a capacitor bank of 416 micro farads in the HVAC system can increase the value of cos phi to 0.95, replacing building lights with 28 watts installed recess type 69 units to meet lighting standards, and the use of PLN electricity will save electricity costs of IDR 2,367,557,200. [ABSTRACT FROM AUTHOR]

At the Coal Power Plant the Electrostatic Precipitator (ESP) functions as a catcher of fine dust that is in the exhaust ducts from coal combustion. It is known that the ash attached to the electrode which has an electric charge is difficult to drop using a vibrator, by using the Power Off Rapping (POR) method, which is to temporarily turn off the electric charge on the electrode; the ash attached to the electrode plate will be more easy to miss. This research is a quantitative research that aims to determine the effect of the ESP operating method on energy consumption, determine the energy consumption ratio of each current setting, determine the dust capture efficiency ratio of each current setting and find energy saving opportunities using the following data analysis techniques. The energy consumption calculation used is only the energy consumption of the rectifier transformer on the electrostatic precipitator excluding hopper heaters, box heaters and rappers. After getting the test results from the current setting simulation, it can be concluded that the current setting of 20% is the most optimal setting in accordance with Ministry of Environment and Forestry Regulation No. 15 of 2019 the threshold limit for particulate exhaust gases at coal fired power plants is 100 mg/Nm3 where the dust reading value is 80.15 mg/m3. By using a current setting of 20%, a savings of 38.97% can be made for the operating method without POR and 41.88% for the POR operating method. If the difference in energy consumption is converted to rupiah by using the electricity tariff for large industrial groups (I-4/TT) of IDR 996.74/kWh, then the savings in electricity costs in 1 month of operation are IDR 176,802,877 without the POR method and IDR 189,988,881 with the POR method. [ABSTRACT FROM AUTHOR]

In this study, an overview of energy performance was obtained from the comparison of refrigerants (R32 to R1270 and R410a to R1270) in split inverter AC equipment. R32 testing was carried out with temperature settings of 16oC and 27oC while R410a was carried out with temperature settings of 18oC and 27oC. At each temperature setting, the cooling load is carried out under conditions using a heater and without loading. In this analysis, a comparison of energy performance and energy efficiency is carried out using the VDMA 24247-2 standard. The results of this study showed that the refrigeration effect value of R1270 was greater than R32 and R410a in all conditions. For compressor work, R1270 has a lower value than R32 and R410a because the value of ΔP (P2-P1) on R1270 is smaller so that the compressor work in the compression process is lower. In terms of system, the efficiency for R1270 in various conditions for replacing R32 is almost the same while for R1270 for replacing R410a, the highest efficiency is at a temperature setting of 16oC, namely at 100% mass condition. Based on the VDMA 24247-2 standard, the highest total energy efficiency value in R32 is 17.17% while in R1270 with a mass of 90%, 100% and 110% is 18.15%, 21.09% and 21.86%. The highest total energy efficiency value in R410a is 5.44% while in R1270 with a mass of 90%, 100% and 110% is 6.25%, 6.22%, 7.42%. [ABSTRACT FROM AUTHOR]

In Indonesia, the common problem in operating breastshot water wheels is wheel operation discontinuity due to low stream velocity in the channel during the dry season. One could minimize this problem by studying the method of maintaining the wheel's operation continuity during the season. Therefore, this study aimed to propose the installation of a water-jumper at the wheel upstream by fabricating water channel laboratory models and a breastshot water wheel. The water-jumper, whose slope angle is adjustable, is attached at the upstream. The study also aimed to investigate the effect of the waterjumper slope on the breastshot wheel's performance. The slope angles were set at 5°, 10°, 15°, 20°, 25°, 30°, 35°, and 40°, and the upstream velocities were 1.1, 1.2, 1.3, 1.4, 1.5, and 1.6 m/s. The result showed that the water-jumper could increase the low stream's gross head and hydraulic power, enhancing the breastshot wheel's torque and output power. The highest efficiency is achieved at the slope of 10° for a stream velocity of 1.3 m/s. Furthermore, the water-jumper significantly affects a stream velocity lower than 1.3 m/s. The hydraulic power is influenced by discharge and gross head, which increase with the waterjumper slope angle. However, higher momentum losses occur at the wheel for stream velocity higher than 1.3 m/s, decreasing the breastshot output power and efficiency while increasing hydraulic power. Overall, the water-jumper could maintain continuous breastshot wheel operation in the irrigation channel during the dry season. [ABSTRACT FROM AUTHOR]

This work was conducted to examine the performance and flow characteristics of a Savonius wind turbine with a corrugated inner surface blade. The unsteady 2-D simulation was performed using ANSYS Fluent with a k-ω SST at a wind velocity of 6,2 m/s. The results showed that the flow structure changes with increasing turbine rotation. The corrugated inner surface of the blade causes an increased high-pressure area on the advancing blade. Besides that, the torque and power coefficients are higher than for semicircular standard blades. This value increases as the free-flow velocity increases. [ABSTRACT FROM AUTHOR]

This experimental study was conducted to investigate the intake manifold performance. The work examined three intake manifold models of tangential, helical port left and port right in the four-strake gasoline engine with load variation. The interesting parameters of torque, power, emission, and thermal efficiency were measured in the test engine. The results showed that the helical port left has a better the performance than tangential port and helical port right. It is shown that increasing in torque, power, and thermal efficiency in the helical port left were higher than in the tangential port and helical port right. [ABSTRACT FROM AUTHOR]

This experimental work carried out to measure the intake manifold performance. The investigation examined three geometry of tangential, helical port left and right model in the four-stroke gasoline engine with rotational speed variation. The results showed that the helical port left model has a better the performance than both tangential port and helical port right. It is indicated by increasing in torque, power, and thermal efficiency in the helical port left were higher than in the tangential port and helical port right. [ABSTRACT FROM AUTHOR]