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Program Studi Teknik Konversi Energi Jurusan Teknik Mesin Politeknik Negeri Semarang Jalan. Prof. H. Soedarto, S.H., Tembalang, Semarang.
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Eksergi: Jurnal Teknik Energi
Published by Politeknik Negeri Semarang
ISSN : 02168685     EISSN : 25286889     DOI : http://dx.doi.org/10.32497/eksergi.v18i2.3605
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Electrical & Electronics Engineering Energy Engineering Mechanical Engineering
Design of DC Accumulator Charging using Backup Accumulator Based on Inverter and Converter Device Parlindungan Pandapotan Marpaung
Arjuna Subject : Energi (semua kategori) - Energi (Lain-Lain)
Articles 260 Documents
 22   23   24   25   26 
Polymer Microfluidics Chip Fabrication and Its Energy Application: A Mini Review Sandi, Dianisa; Li, Yang; Evan, Bah; Efendi, Erwan Tri; Huda, Luqman Al; Fajri, Amrisal Kamal; Prihatmini, Eri
Eksergi Vol. 21 No. 01 (2025): JANUARY 2025
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v21i01.6352

Abstract

Microfluidics is a technology that manipulates fluids at a microscale and has shown great potential in various fields, including energy. This mini-review discusses common microfluidic materials and the main techniques in microfluidic chip fabrication, such as photolithography, soft lithography, and 3D printing-based fabrication methods. Furthermore, several applications of microfluidic chips in the energy sector, such as solar energy and fuel cell systems development, are also discussed. The use of microfluidic chips in energy systems offers high efficiency, low material consumption, and good system integration. This review aims to provide an overview of the progress of microfluidic chip fabrication and its energy potential applications.
Validation Insulation Resistance Testing and Reliability Assessment of 6 kV Current Transformers for High Voltage Applications Suwarti, Suwarti; Hermawan, Natanael Yonando; Fajri, Amrisal Kamal; Samaratungga, Langga
Eksergi Vol. 21 No. 01 (2025): JANUARY 2025
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v21i01.6357

Abstract

Current transformers (CTs) are critical components in electrical power systems, particularly for measurement and protection functions in high-voltage systems. However, the performance and operational safety of CTs heavily depend on the quality of their insulation. A common issue encountered is insulation degradation due to aging, humidity, or external disturbances, which can lead to system faults or even complete equipment failure. This study aims to evaluate the insulation condition of a 6 kV CT through insulation resistance testing. The method employed involves measuring the insulation resistance using a megohmmeter with a direct current (DC) test voltage, where resistance values are recorded in megaohms (MΩ) up to gigaohms (GΩ). The test results showed an average resistance value of 145.5 GΩ, significantly exceeding the minimum threshold of 1 MΩ per kilovolt as stipulated in international standards (VDE 228/4). Therefore, it can be concluded that the CT insulation is in excellent condition and is reliably suitable for operation in high-voltage systems.
Validation of Pressure Transmitter Input/Output Loop Testing Based on Hybrid Analog and Digital HART Communication Wintio, Rafii Trimetta; Dionova, Brainvendra Widi; Yusuf, Ahmad
Eksergi Vol. 21 No. 01 (2025): JANUARY 2025
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v21i01.6358

Abstract

The use of the 4–20 mA analog signal remains a foundational standard in industrial measurement and control systems, despite the continuous advancement of digital communication technologies. This study implements a hybrid validation approach that integrates the conventional 4–20 mA analog signal with HART (Highway Addressable Remote Transducer) digital communication for conducting Input/Output (I/O) loop testing on pressure transmitters. The primary objective is to ensure the accuracy and reliability of signal transmission from field instruments to control systems such as Programmable Logic Controllers (PLCs) or Flow Computers. Utilizing a HART modem and FieldMate software, analog signals are injected and digitally monitored to verify transmitter output against predefined tolerance standards. Test results indicate that all evaluated transmitters maintained an error level below the 0.25% threshold, in compliance with standards set by the Directorate of Metrology and ASTM/API guidelines. The integration of HART communication significantly enhances testing efficiency, diagnostic capability, and remote configuration flexibility, underscoring the critical role of hybrid validation approaches in modern industrial instrumentation systems
The Effectiveness of Mechanical Power on An Auxiliary Rotor in The Design of Counter Rotating Wind Turbine (CRWT) Huda, Luqman Al; Evan, Bah; Prasetya, Ari; Sandi, Dianisa Khoirum; Prihatmini, Eri; Fajri, Amrisal Kamal
Eksergi Vol. 21 No. 01 (2025): JANUARY 2025
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v21i01.6359

Abstract

The counter-rotating wind turbine (CRWT) represents a novel development in horizontal-axis wind turbine technology. This innovative design incorporates an additional rotor that rotates in unison with the main rotor along the same axis. Without the supplementary rotor, the turbine's configuration is analogous to that of a horizontal-axis wind turbine (HAWT) with the main rotor functioning independently. The primary objective of this study is to undertake a comparative analysis of the effectiveness of mechanical energy generation, as measured by torque, between the CRWT and HAWT designs. The configuration of the wind turbine is situated within a wind tunnel, characterized by a rectangular cross-section. The testing of wind turbines has been conducted at wind velocity of 2 m/s, 3 m/s, and 4.5 m/s. The total mechanical power measured was 0.14 W, 0.21 W, and 0.28 W at wind velocity of 2 m/s, 3 m/s, and 4.5 m/s, respectively. The final results of the study have analyzed the effectiveness of power enhancement through power coefficients.
Simulation of Automatic Solar Tracker Control System Using Proteus Application Efendi, Erwan Tri; Wibowo, Bayu Setyo; Dhiyaussalam, Dhiyaussalam; Wardhany, Arum Kusuma; Wibisono , Arifin
Eksergi Vol. 20 No. 03 (2024): SEPTEMBER 2024
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v20i03.6360

Abstract

As a tropical country, Indonesia possesses significant renewable energy potential, particularly from solar and wind sources. However, seasonal variations—such as high solar intensity during the dry season and increased wind speeds during the rainy season—pose challenges to optimizing solar cell utilization. While solar energy presents an ideal solution for clean energy transition, static photovoltaic (PV) systems suffer from efficiency limitations due to their inability to track the sun’s movement. Dual-axis solar trackers can enhance energy efficiency by 25–35% compared to fixed systems, particularly in tropical regions with dynamic solar positioning. However, large-scale physical implementation requires substantial investment, making simulation tools like Proteus essential for computational validation prior to real-world deployment. Proteus facilitates comprehensive modeling of LDR sensors, servo motors, and microcontroller-based control algorithms (e.g., Arduino) in a precise virtual environment. This approach also evaluates the impact of tropical conditions (e.g., humidity, rainfall) on system reliability while optimizing designs to reduce costs. Integrating current research with Proteus simulations offers a robust methodology to accelerate solar tracker adoption in Indonesia.
Operational Assessment of Shell and Tube High Pressure Heater in PT Sumber Segara Primadaya's 300 MW Unit 2 Power Plant Mulyono, Mulyono; Efendi, Erwan Tri; Setiyawan, Rayhan Muhammad Faqi Fikar; Sandi, Dianisa Khoirum; Dhiyaussalam , Dhiyaussalam
Eksergi Vol. 21 No. 01 (2025): JANUARY 2025
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v21i01.6361

Abstract

Electricity is a fundamental necessity, with Indonesia's per capita consumption reaching 1.73 kWh/capita in 2022—a 4% increase from 2021 and the highest in five decades. Projections indicate demand will surge to 1,885 TWh by 2060, with per capita consumption exceeding 5,000 kWh, underscoring the need for efficient power generation. In coal-fired power plants (PLTU), high-pressure shell-and-tube heat exchangers are critical for optimizing efficiency, recovering waste heat to preheat boiler feedwater, reducing fuel use by 5–10%, and minimizing emissions. This study evaluates the performance of these heat exchangers at PT Sumber Segara Primadaya PLTU Cilacap, a major Indonesian PLTU with units totaling 2,260 MW capacity. By analyzing operational effectiveness, this research aims to enhance maintenance strategies and maximize energy output, supporting Indonesia's growing electricity demands while improving thermal efficiency in coal-dependent power systems.
Design of Development Waste Heat Recovery in Metal Casting Industry: Exploring Energy Saving Potentials Saiful, Rifki; Hilmi, Erik; Uhanto, Uhanto; Arneta, Vanesa; Dewi, Shanaya Rifiana
Eksergi Vol. 22 No. 01 (2026): JANUARY 2026
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v22i01.7138

Abstract

The metal casting industry is known for its energy-intensive consumption and the generation of large amounts of waste heat and materials during the melting, casting, and cooling processes. If this heat is not utilized properly, it not only causes environmental degradation but also contributes to significant economic inefficiencies. Therefore, the need for more sustainable practices is increasingly driving the industry to seek solutions to optimize energy consumption and reduce waste. One promising solution is the implementation of waste heat recovery (WHR) systems, which aim to model waste heat recovery, evaluate potential energy savings, and provide solutions to improve sustainability in the sector. By developing hybrid system designs that combine fossil fuels and renewable energy sources, such as solar panels (PV), batteries, and inverters, the industry can reduce its reliance on fossil fuels while improving overall energy efficiency. Furthermore, the implementation of WHR technology not only offers technical benefits but also contributes to lower operational expenses and carbon emissions, as demonstrated by the reduction in unit production costs from various simulations. These results demonstrate that this new system has positive economic and environmental impacts, creating a more environmentally friendly and sustainable solution for the metal casting industry.
Sustainable Production of Biodiesel Using Eggshell-Derived CaO/K₂O Catalyst: Influence of Process Variables and Factorial Design Analysis Prabowo, Agung; Syarifuddin Oko; Muh Irwan; Alvyano; Gading Bagus Mahardika
Eksergi Vol. 22 No. 01 (2026): JANUARY 2026
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v22i01.7153

Abstract

This study investigates the effects of CaO/K₂O catalyst mass (X₁) and reaction time (X₂) on biodiesel yield produced from waste cooking oil via transesterification. A 2² factorial design was employed to evaluate the main and interaction effects of both parameters. Analysis of variance (ANOVA) confirmed that the developed regression model was statistically significant (p = 0.0253) with a high coefficient of determination (R² = 0.9386), indicating excellent model adequacy. The reaction time (X₂) exhibited the most significant positive effect on biodiesel yield (t = 5.96), while the catalyst mass (X₁) showed a negligible influence. The interaction term (X₁X₂) presented a moderate negative effect, suggesting that excessive catalyst loading combined with longer reaction duration may slightly decrease yield due to soap formation and emulsification. The contour profiler revealed that yield increases with both factors up to an optimum point, after which further catalyst addition provides minimal improvement. The optimum conditions were achieved at a catalyst mass of 4.5 g and a reaction time of 4.5 h, resulting in a biodiesel yield of 70.3%. These findings confirm that reaction time is the dominant factor affecting transesterification efficiency, and that CaO/K₂O derived from waste eggshells serves as an effective and sustainable heterogeneous catalyst.
Study of potential energy at Sport Field Using PV Syst Sumarno, Radiktyo Nindyo; Mariani, Dina
Eksergi Vol. 22 No. 01 (2026): JANUARY 2026
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v22i01.7202

Abstract

Escalating global power consumption requires an urgent shift toward renewable energy technologies. This study analyzes the potential of a solar power plant (PLTS) at the Sport Field of Universitas Muhammadiyah Semarang. The researchers utilized PVsyst software to simulate an off-grid system design with a capacity of 12.65 kWp. The simulation evaluated five tilt angle variations ranging from 15o to 35o using Neosun 550 Wp modules. The analysis identifies the 15o tilt angle as the most optimal configuration. This specific setup generates 18.603 MWh of electrical energy annually. The system records maximum production in August and minimum production in January. The research confirms the feasibility of implementing this off-grid system to support facility operations.
Industrial Boiler Performance Assessment Using Combined Heat Loss and Input–Output Efficiency Methods: A Pulverized Coal Power Plant Case Study Surendra, Denny
Eksergi Vol. 22 No. 01 (2026): JANUARY 2026
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v22i01.7479

Abstract

Reliable evaluation of boiler thermal performance is essential for improving fuel utilization and operational stability in coal-fired power plants. Although boiler efficiency is commonly assessed using either heat-loss diagnostics or input–output energy balance, few industrial studies integrate both approaches to interpret real operational behavior under steady conditions. This study presents an integrated thermodynamic and operational analysis of a large-scale pulverized coal boiler operating at a steam power plant in Jepara, Indonesia. Field operational data were obtained from the plant distributed control system during stable operation, and corresponding coal samples were laboratory-tested to determine the High Heating Value (HHV). Boiler efficiency was evaluated using both the indirect heat-loss method and the direct input–output method across seven representative datasets. The indirect analysis yields efficiencies of 88.48–89.95%, with dominant losses associated with dry flue gas sensible heat and hydrogen-related vapor formation. The direct evaluation produces efficiencies of 87.53–89.64%, confirming stable near-constant load operation with adaptive fuel control. The results indicate that efficiency variations are governed primarily by combustion stability and thermodynamic loss structure rather than fuel calorific value alone

Page 26 of 26 | Total Record : 260

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