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All Journal Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Eksergi: Jurnal Teknik Energi
Sandi, Dianisa Khoirum
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Astronomy Chemical Engineering, Chemistry & Bioengineering Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology Mechanical Engineering Physics

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Thermoelectric Conversion of Motorcycle Exhaust Heat into Alternative Electrical Energy: A Mini Review Pranata, Ragil Tri; Irawan, Nanda Satria; Santosa, Alvian Rizky; Althaf, Muhammad; Adinata, Bintang; Yang, Lee; Sandi, Dianisa Khoirum
Eksergi Vol. 21 No. 02 (2025): MAY 2025
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v21i02.6845

Abstract

Heat energy can be harnessed as an alternative source for electricity generation, including waste heat from motorcycle exhaust. Thermoelectric technology enables the direct conversion of this waste heat into electrical energy. This mini-review examines the utilization of motorcycle exhaust heat through thermoelectric systems. The findings indicate that exhaust temperatures can activate thermoelectric modules to produce electrical power, which can be used for applications such as motorcycle-mounted cell phone chargers. The generated electricity can also be stored in batteries to power lighting systems. Given Indonesia's high number of motorcycles, this technology shows strong potential for small-scale renewable energy generation, supporting advancements in sustainable energy solutions.
Biofuel as a Renewable Energy: Potential, Technology, and Challenges Towards a Sustainable Energy Transition Sandi, Dianisa Khoirum; Atyanta, Ariefanda Irza; Fifalah, Maisa Linta; Rizqi, Fika Ariza
Eksergi Vol. 21 No. 03 (2025): SEPTEMBER 2025
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/eksergi.v21i03.7115

Abstract

Biofuel is a promising renewable energy alternative to reduce dependence on fossil fuels and lower greenhouse gas emissions. This article presents a comprehensive overview of biofuel classification (generation I–IV and physical forms), production technologies (fermentation, transesterification, gasification, pyrolysis), and the applications of bioethanol, biodiesel, and biogas in the transportation, industrial, and power generation sectors. Energy efficiency and environmental impact analyses are conducted using a life cycle assessment (LCA) approach, while national energy policies are examined in the Indonesian context, including the mandatory blending program (B30–B50) and sustainability strategies. While biofuels have significant potential, challenges such as production efficiency, land conflicts, and regulatory consistency need to be addressed for biofuels to truly contribute to the national energy transition
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.
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.
Microstructure and Optical Properties Study of Nd-doped BiFeO3 (Ba1-xNdxFeO3) Films on Quartz Substrate Iriani, Yofentina; Sandi, Dianisa Khoirum; Nurmawanti, Rainisa; Budiawanti, Sri; Agustina, Elvinda Bendra
Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Vol. 11 No. 2 (2021)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpfa.v11n2.p148-157

Abstract

Bismuth ferrite oxide (BFO), due to its remarkable properties, has become one of the most attractive multiferroic materials to be extensively studied. BFO doped with various materials, including Neodymium (Nd), could improve its properties that apply to numerous electronic devices. However, the studies related to the properties of Nd-doped BFO (Ba1-xNdxFeO3) thin films on a quartz substrate, especially the optical properties, are relatively scarce. This study aimed to investigate the microstructure and optical properties of the Nd-doped BFO (BNFO) as the variation of the Nd concentrations. The BNFO thin films with Nd concentrations of 0.05 (BNFO5); 0.1 (BNFO10); and 0.2 (BNFO20) have been deposited on the quartz substrates via the sol-gel method and using spin coating. The films were annealed at 600 °C for 1.5 h. The XRD result of the BNFO films revealed a single phase of BFO with a cubic structure. The lattice constants and volume cells of the films declined with more Nd. Meanwhile, the crystallite size and lattice strain changed due to the change in the Nd number. Additionally, the morphology images showed the pores on the films’ surface and the different film thicknesses of each BNFO film. From the optical characterization, the transmittance spectra of the BNFO films tended to rise as the more Nd amount doped, in which the BNFO20 had the highest transmittance. The BNFO10 had the highest refractive index, followed by the BNFO5 and BNFO20. Contrarily, the BNFO20 had the highest extinction coefficient and  spectra, followed by the BNFO5 and BNFO10. Further, the bandgap values of the BNFO5, BNFO10, and BNFO20 were 2.75, 2.85, and 2.64 eV, respectively. Accordingly, due to the highest Nd amount that most impacted its microstructure, the BNFO20 exhibited the lowest bandgap value compared to the other films that are good for photovoltaic applications.
Co-Authors Adinata, Bintang Agustina, Elvinda Bendra Althaf, Muhammad Ari Prasetya, Ari Atyanta, Ariefanda Irza Dhiyaussalam , Dhiyaussalam Efendi, Erwan Tri Evan, Bah Fajri, Amrisal Kamal Fifalah, Maisa Linta Huda, Luqman Al Irawan, Nanda Satria Mulyono Mulyono Nurmawanti, Rainisa Pranata, Ragil Tri Prihatmini, Eri Rizqi, Fika Ariza Santosa, Alvian Rizky Setiyawan, Rayhan Muhammad Faqi Fikar Sri Budiawanti Yang, Lee Yofentina Iriani