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PT. POMI Paiton Unit 3 is one of big steam power plant in Indonesia that provideelectricity with a capacity of 1 x 815 MW. This power plant requires a large amount ofcoal to produce electricity with a lot of large quantities, estimates of the total consume coalamounted to 3.06 million tons / year. The performance of the power plant PT. POMI Unit3 can be optimized by modifying the Heat Exchanger Network (HEN). Pinch method isused to optimize HEN, this method provides a good opportunity in the design or inevaluating HEN system. Research has been carried capable increase efficiency of 0.5% ofthe power plant that was originally 28.45% to 28.95%, and can reduce fuel use by 1.71 kg/ s initially as much as 97.99 kg / s to 96.28 kg / s, and can also be reconstructed from there-arrangement of Heat Exchanger Network of Power Plant PT. POMI Unit 3 Paiton.

This study aims to investigate the performance of using a Diffuser on a horizontal wind turbine. Diffuser variation used has two different geometries : without an Inlet Shroud (L/D = 0.25) and with an Inlet Shroud (L/D = 0.39). The wind turbine’s test is performed on a wind tunnel with a low wind speed ranging from 1 m/s to 5 m/s. The results showed that with the addition of a Diffuser, the power produced shows an increased. Variation of the Diffuser without an Inlet Shroud is able to increase power efficiency up to 20.5% while the Diffuser with an Inlet Shroud can increase power efficiency up to 41.1%. This suggests that the use of a Diffuser is capable of improving the performance of the wind turbines by improving produced power efficiency.

The binary power plant is a geothermal power generation system used at low to medium temperature levels and used indirect system. In this system, the heat generated from the reservoir is channelled to the secondary working fluid which has a lower boiling point than water using a heat exchanger. In this case, the Organic Rankine Cycle (ORC) is a suitable system for use. This improves the performance and efficiency of the plants. However, in this system, the installation configuration of the ORC model is an important factor that can affect its performance. The selection of an improper ORC design reduces the thermal efficiency of the system. Therefore, it cannot utilize heat optimally. In this study, Engineering Equation Solution (EES) simulation program is used to run the system as in operation conditions. A comparative analysis is conducted using ORC, Regenerative ORC (RORC), and RORC with Internal Heat Exchanger (IHE). The results indicate that RORC with IHE has the greatest value for both energy (21.74%) and exergy efficiency (25.26%) while net power produced 5479 kW. This shows the addition of OFOH and IHE can increase these factors, improve performance and reduce energy degradation from the cycle.

The aim of this research is to analyze the effect of using immersion cooling with different flow rate and fan rotation on decreasing the temperature on CPU. The study used three variables of flow rate: 0.5, 1 and 1.5lpm. in addition, three other variables of fan rotation, 400, 600, and 800 rpm, were used as well. Data collection was by means of benchmark software to load the CPU to work maximum and the logging software to record the temperature. The results show that the immersion cooling could potentially be utilized as the new and more effective cooling system. The most optimum variable to decrease the temperature was 1, 5 lpm with fan rotation at 800 rpm. It decreased the maximum temperature from 60 °C to 47 °C, a deviation of 13 °C lower compared to the conventional fan cooling system with air as a medium. The study established that the higher the flow rate and the fan rotation, the higher temperature can be decrease. Therefore, immersion cooling can be the solution to decrease the consumption of energy on IT sector on a bigger scale.

Organic Rankine Cycle is a technology that convert low-temperature heat sources into a mechanical energy, and it can be used to produce electrical energy in a closed system. The heat sources can be received from renewable energy such as geothermal, solar, and biomass. Furthermore, the ORC system can also be used to increase energy efficiency in the industry by utilizing the waste heat produced. Therefore, there are two classification of the ORC system, namely a heat recovery system and binary power plant. Recently, the ORC system has made a thrive in the geothermal power plant. The ORC system can be applied to resources with low to medium temperature characteristics (

The utility of the world internet is on the rise as it is recorded that 46% of the world’s population have become internet users who generates data traffic of up to 8 zettabytes daily. This increase has triggered the growth of data center infrastructure as processing, storage and communication system in the digital world. The data center itself has contributed 1.5% to the total world electricity consumption and this is expected to increase with time. The proportion of energy used in the data center covers 52% for information technology (IT) equipment, 38% for cooling and 10% for supporting devices. One of the problems faced by these centers over the years is the cooling of the information technology (IT) components. This paper describes a cooling model that has the potential to improve the efficiency of energy used in data centers. Numerous studies have been carried out and one of them involves the use of immersion cooling technique as it promises improvements in the energy efficiency of data centers, using dielectric fluids that have high heat capacity. Several types of fluid used in this method are identified and discussed in this paper.

The exergy analysis of steam power plant system in PT. Jawa Power-YTL, East Java unit 5 was performed based on the first and second law of thermodynamics. Exergy flow and exergy efficiency were calculated for each component of the plant i.e. the boiler, HTP, IPT, LPT, deaerator, condenser, HPH, LPH, CEP and FWP. The exergy steam-flow of 970288 kW produced 610.000 kW of electricity with an exergy efficiency of 26.36%. Sankey diagram showed the exergy loss on each component of the steam power plant. The irreversibility of the boiler, condenser, turbine, LPH, HPH, pump and daerator were 1677003 kW (17,28 %), 738122 kW (7,61 %), 152894 kW (1,58 %), 111881 kW (1,15 %), 470520 kW (4,85 %), 193494 kW (1,99 %) and 1081771 kW (11,15 %), respectively. The total exergy that could be converted into electrical energy in the system was 5276259 kW (54,39%). The highest irreversibility was in the boiler with 1677003 kW (17,28%). The optimization result showed that the highest efficiency was 94.04% at an output pressure of 41 bar.

This study aims to improve the performance of HAWT's wind turbines in low wind speeds condition. There are two possible approaches: developing low-speed rotor technology and improving the turbine's blades. In this research, we improve the turbine's blades by determining the type of airfoil, material and pitch angle. The airfoil used as its blade is NACA 4412 with teak wood material. Variations of pitch angles are at 0 ° 2 ° 4 ° 6 ° 8 ° 10 ° and 12 °. Testing is realized by making an artificial wind in the wind tunnel. The imitation speed are of 2 m/s, 2.5 m/s, 3 m/s, 3.5 m/s, 4 m/s, 4.5 m/s and 5 m/s. The result shows that at 4° is the best pitch angle that produces the maximum power output and rpm. The 4° pitch angle has a cut in of 2m/s wind speed and generates a power output of 9.71 Watt at an average Rpm of 505.6. The increasing pitch angle decreases the power output and RPM generator.

Worldwide energy usage continues to increase along with the depletion of fossil fuel reserves. This condition encourages society to develop renewable energy. Wind is one of the form of renewable energy which has low utilization. Furthermore, the available wind turbine has low efficiency especially in low wind speed condition. One way to improve a wind turbine's performance in a low wind speed is the use of pitch angles. This study aims to determine the effect of pitch angle on SG-6043 wind turbine, the pitch angle variations used are 0°, 2°, 4°, 6°, 8°, 10°, 12° and 14°. The data were collected using an experimental wind tunnel. The test results show that the pitch angle of 10° produces the most optimal power when compared to other angles, which is 6.82 watts, whereas the angles 0°, 2°, 4°, 6°, 8°, 12° and 14° produces power of 0; 0; 0; 0; 6.50; 6.55; 6.30 watts respectively.