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Heat stress is a major constraint in broiler production systems located in humid tropical climates, where high ambient temperature and relative humidity impair growth performance, feed efficiency, and animal welfare. This systematic review synthesizes peer-reviewed studies published between January 2015 and December 2025 evaluating environmental housing designs and cooling strategies for mitigating heat stress in broiler chickens. This systematic review followed the PRISMA 2020 guidelines and synthesized peer-reviewed studies retrieved from Scopus, Web of Science, and ScienceDirect, published between January 2015 and December 2025. From 500 records initially identified, 26 studies fulfilled the predefined eligibility criteria and were included in the qualitative synthesis. The findings demonstrate that evaporative cooling systems, tunnel ventilation, and automated climate control technologies consistently reduced indoor temperature (2–6°C) and improved body weight gain, feed conversion ratio (FCR), and mortality rates under hot-humid conditions. However, cooling efficiency was strongly influenced by ambient humidity, necessitating integrated and adaptive environmental control approaches. Smart sensor-based systems further enhanced microclimate stability and thermal uniformity within broiler houses. Beyond performance improvements, optimized environmental management reduced physiological stress indicators, including heterophil-to-lymphocyte ratios and corticosterone levels. Overall, integrated, humidity-adaptive, and energy-efficient cooling strategies are essential to sustain productivity, welfare, and climate resilience in tropical broiler production systems.

Diesel engines are widely used in the transportation and industrial sectors due to their high thermal efficiency and good operational durability. However, increased fuel consumption due to inefficiency of the injection system remains a common problem. Injector characteristics, particularly nozzle diameter and injection pressure, are important factors that affect the quality of fuel atomization, air-fuel mixing, and combustion efficiency. An inappropriate combination of parameters can cause suboptimal combustion and increase fuel consumption. This study aims to analyze the effect of variations in nozzle diameter and injection pressure on fuel consumption efficiency in diesel engines. The method used is an experiment with variations in nozzle diameter of 0.150 mm, 0.152 mm, and 0.154 mm and injection pressures of 400 bar, 420 bar, and 440 bar. Tests were conducted at engine speeds of 500 rpm, 1000 rpm, and 1500 rpm with a fuel consumption measurement time of one minute for each parameter combination. Fuel consumption was measured using the volumetric method and analyzed through the fuel volumetric flow rate, fuel mass flow rate, Brake Power (BP), and Brake Specific Fuel Consumption (BSFC). The results showed that the combination of a nozzle diameter of 0.150 mm and an injection pressure of 400 bar produced the lowest BSFC value, thus providing the best fuel consumption efficiency. Meanwhile, the combination of a nozzle diameter of 0.152 mm and an injection pressure of 420 bar showed the closest condition to optimal because it was able to provide a balance between atomization quality and the amount of fuel injected, resulting in efficient and stable combustion. Thus, the efficiency of a diesel engine is influenced by the balance of nozzle size and injection pressure, not solely by the lowest fuel consumption.

This study aims to analyze the development of studies on the use of biomass as a renewable energy source to support national energy security using a bibliometric approach. Research data were obtained from the Scopus, Web of Science, and Google Scholar databases with a publication range of 2015-2025. The analysis was conducted using VOSviewer and Biblioshiny. The results show a significant increase in publication trends in the last decade, especially in the period 2016-2024, reflecting the increasing academic attention to biomass as a solution in the energy transition. Keyword visualization shows that biomass is closely related to concepts such as combustion, thermal efficiency, calorific value, and pelletizing. China is the country with the highest publication contribution, while Indonesia is strategically positioned due to its abundant biomass waste potential. Overall, biomass has great potential to support energy diversification, reduce dependence on fossil fuels, and strengthen national energy security in a sustainable manner.

This research aims to analyze the influence of thermal conditions; specifically the temperature difference between the test object and the environment; on the characteristics of air flow and heat transfer around it. The object of this study is a test piece subjected to free air flow under various temperature conditions; focusing on the convection heat transfer phenomenon. The main problem addressed is how temperature variations affect the convection heat transfer coefficient; heat transfer rate; and heat flux; as well as changes in air velocity and pressure profiles. Therefore; the objective of this research is to quantitatively compare and assess these thermal and fluid parameters through an experimental study approach and Computational Fluid Dynamics (CFD) simulation. The methodology involves direct measurement of temperature and pressure parameters under low and high-temperature conditions; which are then processed to determine the convection coefficient (); heat transfer rate (); and heat flux (). The main findings indicate that at low-temperature conditions; the heat transfer coefficient () was found to be 53.26 ; the heat transfer rate () was 24.99 W; and the heat flux () was 537.87 ; with a pressure drop of 0.86 Pa. In conclusion; thermal conditions play a crucial role in determining the dynamics of air flow and the efficiency of heat transfer; the greater the temperature difference (); the higher the potential heat transfer rate; establishing a strong correlation between thermal conditions and the convection phenomenon.

The low thermal efficiency of Gas Power Plants (PLTG) due to exhaust gas heat loss drives the implementation of cogeneration at PLTGU Block II PT. PLN Indonesia Power UBP Semarang. This study analyzes the performance of the Gas Turbine Generator (GTG), combined cycle efficiency, and Exergy distribution using a 3-3-1 configuration. The research utilizes actual operational data from January 28, 2026, sampled at 10-minute intervals. Results indicate that cogeneration via a Heat Recovery Steam Generator (HRSG) significantly enhances plant efficiency. The GTG output ranged from 273–283 MW with an efficiency of 30.0–30.2%. Following combined cycle integration, system efficiency increased to 43.9–44.4%, a gain of approximately 14%, with a heat rate of 11,916–11,988 kJ/kWh. Exhaust heat of 665–713 MW was recovered to generate an additional 130 MW through the Steam Turbine Generator (STG). Exergy analysis reveals that the largest irreversibility occurs in the GTG combustion process (285 MW), followed by the HRSG (185 MW) and STG (49 MW).

The global energy crisis and climate change are driving the development of biodiesel as a renewable energy source. Graphite as an additive shows significant potential in improving the efficiency and reducing emissions of biodiesel. This study maps graphite-biodiesel research in Southeast Asia using a meta analysis of systematic reviews of 68 publications from Scopus, Web of Science, and ScienceDirect from 2015-2024. The results show that Malaysia leads in publication contributions (32%), followed by Thailand (28%) and Indonesia (18%). The optimal graphite concentration of 50 ppm increases brake thermal efficiency by 8.3% and reduces CO (15.7%), HC (12.4%), and smoke (18.9%) emissions, although there is an increase in NOx (6.8%). Palm oil methyl ester dominated the research (56%). Indonesia has strategic opportunities with abundant feedstock and graphite deposits, but faces challenges in research infrastructure, limited international collaboration, and the absence of an integrated national roadmap. Infrastructure investment, human resource strengthening, and industry academia collaboration are needed to accelerate national biodiesel research.

This study aims to analyze the temperature distribution in an LPG-fueled chili drying machine using Computational Fluid Dynamics (CFD) simulation. The simulation was performed using SolidWorks Flow Simulation 2022 to investigate the effect of inlet air temperature and velocity on temperature uniformity inside the drying chamber. Three inlet temperature variations were applied: 60°C, 70°C, and 80°C, combined with two air velocities of 10 m/s and 11 m/s. The results showed that these parameters significantly influence temperature distribution. The optimum condition was achieved at 70°C and 10 m/s with a temperature uniformity efficiency (

Steam turbines remain a core technology in thermal power generation and continue to evolve through advances in aerothermal design, materials, control strategies, and digital maintenance. This paper presents a systematic literature review (SLR) of recent international studies published between 2020 and 2025 to synthesize current developments in steam turbine performance and thermal efficiency improvement. Article identification was conducted through SCOPUS using keywords related to turbine efficiency, blade/nozzle optimization, failure analysis, and material enhancement. The selected studies were analyzed thematically across four domains: (1) design and optimization using CFD/FEA, (2) material and structural resilience, (3) operational performance under variable/part-load conditions, and (4) integration with hybrid renewable systems and predictive maintenance. The reviewed evidence indicates that CFD-based nozzle/blade optimization and advanced control approaches can yield measurable efficiency improvements (approximately 2–7.3%), while material innovations and enhanced cooling strategies improve durability by mitigating thermal stress and fatigue risks. In parallel, digitalization through IoT-based predictive maintenance and additive manufacturing is increasingly reported as a pathway to reduce downtime and accelerate component production. However, recurring gaps include limited real-world validation, insufficient studies in humid/tropical environments, and a lack of long-term economic/lifecycle assessments. Future work should prioritize experimental or field verification, region-specific performance studies, and integrated techno-economic evaluation to support broader deployment of high-efficiency steam turbine systems.

Cooling towers are widely used in various industrial applications for water cooling systems. In these towers, water is cooled by air, and the heat released from the water to the air consists of both sensible and latent heat. The efficiency of this heat transfer significantly impacts the performance of the cooling tower. Objective: This study aims to determine the effectiveness and mass flow rate of water in a cooling tower, focusing on the relationship between water temperature, flow rates, and overall cooling tower performance. Method: The analysis includes measurement of the water temperature (48.176 °C), mass flow rate (175.235 kg/s), and the wet bulb temperature (16.988 °C) in the cooling tower. These parameters are analyzed to assess the cooling tower's performance in terms of its heat transfer efficiency. Results: The cooling tower's performance analysis shows an effectiveness of 59.36%. The mass flow rate of water is 175.235 kg/s, and the hot water flow rate is 9373.32 kg/s. The data indicate that the improved water flow and air flow have a positive impact on the heat transfer rate. Novelty: This study highlights the critical role of maintenance and the optimization of flow rates and cooling tower components in enhancing the heat transfer efficiency. It offers valuable insights into the relationship between operational parameters and cooling tower performance. Implications: The findings suggest that proper maintenance and improvements to water and air flow can significantly enhance cooling tower efficiency, leading to better heat transfer and overall system performance. This has important implications for industrial applications that rely on cooling towers for effective water cooling systems.

Energy efficiency in water heaters is a crucial factor in ship operational environments due to limited electricity resources that rely on generators. This study aims to design and build an IoT-based water heater monitoring system with an innovative heat storage medium in the form of a mixture of silica sand and paraffin wax to improve thermal efficiency. Although previous studies have developed temperature monitoring and control systems in IoT-based water heaters, this study specifically fills this gap by analyzing the performance of adding silica sand to overcome the low thermal conductivity of paraffin wax. Using the Research and Development (R&D) method, this system was built with an ESP32 microcontroller as the control center, a DS18B20 temperature sensor for accurate measurements, and the Blynk and Google Sheets platforms for real-time monitoring and data recording. Performance testing was conducted by comparing the water heating rate between pure paraffin wax media and the mixed media. The results showed that the monitoring system functioned reliably, and the main finding proved that the addition of silica sand to paraffin wax significantly increased heating efficiency. This was clearly seen from the reduction in time required to raise the water temperature to 40°C, from 2.5 hours to only 1 hour in the second heating cycle. The results of this study indicate that the integration of silica sand and paraffin wax media with IoT technology can increase the efficiency of water heaters and provide an innovative solution for energy-efficient and environmentally friendly temperature control.

The growing demand for energy-efficient and intelligent thermal systems has driven significant advancements in adaptive compressor design. This paper presents a comprehensive literature review on the development of AI-based compressor systems, with a specific focus on enhancing efficiency under partial-load conditions and optimizing the utilization of residual energy. Through the synthesis of five recent high-impact studies (2020–2025), we examine the application of deep reinforcement learning (DRL), hybrid evolutionary algorithms, and neural network surrogate modeling in compressor optimization. Key findings indicate that model-based DRL combined with surrogate CFD can achieve up to 8% efficiency gains at off-design conditions. Hybrid approaches integrating Genetic Algorithms (GA) with DRL reduce optimization time by 30% while improving pressure ratios. Neural network surrogates provide high-speed, real-time performance predictions with less than 1% error, enabling mass iterative design. Furthermore, intelligent load classification using radial basis function networks (RBFN) allows adaptive response to varying operating conditions with over 95% accuracy. Collectively, these methods form a framework for intelligent, self-optimizing compressor systems capable of real-time adaptation and energy recovery. The results suggest that AI-enhanced adaptive compressors represent a transformative direction for energy-sensitive sectors, including HVAC, power generation, and sustainable industry.

This study aims to systematically evaluate the effect of Exhaust Gas Recirculation (EGR) variation on engine performance and exhaust emissions in dual-fuel diesel–CNG compression ignition engines, in response to increasing emission regulations and the need for cleaner yet practical combustion technologies. The research employs a comparative review approach, synthesizing experimental findings from selected peer-reviewed studies to analyze the influence of different EGR rates on key performance indicators, including Brake Thermal Efficiency (BTE) and Brake Specific Fuel Consumption (BSFC), as well as major emission components such as NOx, HC, CO, and smoke. The findings indicate that increasing EGR rates effectively reduce NOx and smoke emissions due to lower combustion temperatures and oxygen dilution; however, excessive EGR leads to deteriorated combustion efficiency, reflected in reduced BTE and increased HC and CO emissions. An intermediate EGR level, particularly around 10%, is consistently identified as providing the most favorable balance between emission reduction and performance retention in dual-fuel diesel–CNG operation. These results imply that optimized EGR control is a critical parameter for improving the environmental performance of dual-fuel engines without significant efficiency penalties, supporting its application as a transitional technology toward cleaner transportation systems. The originality of this study lies in its integrated comparative synthesis of performance–emission trade-offs across multiple EGR levels and fuel substitution ratios, offering a clearer operational insight that is not explicitly addressed in individual experimental studies.

This study formulates a design concept for the Beach Tourism Resort Area in Botubarani Village by applying tropical architecture that responds to coastal climatic conditions while enhancing the quality of visitor experiences. The research integrates principles of thermal comfort, environmental sustainability, and the ecological potential of coastal environments as the basis for creating climate-adaptive and environmentally responsive tourism areas. The methodology includes site analysis, field observation, climatological assessment, and a literature review related to tropical architecture and coastal tourism design. The collected data were used to determine building orientation, mass layout patterns, visitor capacity, materials, vegetation, and utility systems appropriate for humid tropical climates. The findings show that the site’s position between the sea and the mountains, combined with full-day sun exposure, requires design strategies that maximize cross-ventilation, utilize sloped roofs, provide natural shading, and apply local materials such as wood, bamboo, and red brick. The large spatial needs based on visitor capacity projections are accommodated through a flexible cluster layout that supports visual and functional connectivity between buildings while incorporating green open spaces to enhance microclimate comfort. The utility system is designed using sustainability principles through greywater–blackwater separation, infiltration wells, and recycling-based waste management. This study confirms that the application of tropical architecture in coastal tourism areas can improve thermal comfort, energy efficiency, and environmental sustainability. These findings guide developing tropical tourism area designs that are more adaptive to climate change and more responsive to visitor needs.

This study aims to compare the thermal efficiency of two aluminum and iron-based pans in the water heating process. This research method uses a mixed approach that includes direct observation (qualitative) and quantitative analysis based on changes in water temperature after heating at two volume variations, namely 0.25 L and 0.5 L. Heating was carried out with two time differences, the total of each experiment was four experiments, with two experiments for five minutes and also two experiments for ten minutes. The results showed that iron pans produced heat of 66,150 J at a volume of 0.25 L and 151,200 J at a volume of 0.5 L. Meanwhile, an aluminum pan could produce heat of 53,550 J at a volume of 0.25 L and 67,200 J at a volume of 0.5 L. The difference in heat value was influenced by the thermal conductivity and physical characteristics of each material. This study provides an understanding of the thermal performance of both pot materials and can be considered in the selection of efficient cooking utensils in the household environment.

Disc discs are the main component in a motorcycle braking system that functions to convert kinetic energy into heat energy through friction. The geometric design of the disc, including the diameter and number of holes, affects the effectiveness of braking as well as the heat dissipation ability. This study aims to analyze the effect of variations in diameter and number of holes on disc discs on braking distance and disc temperature. The research method used was an experimental method with three variations in disc diameter (190 mm, 220 mm, and 260 mm) and three variations in the number of holes (30, 36, and 42 holes). The test was carried out through a controlled braking procedure at an initial speed of 40 km/h on flat road surfaces with stable weather conditions. Braking distance data is measured using ultrasonic sensors, while disc temperature is recorded with a high-accuracy infrared thermometer. The results showed that the diameter of the disc disc had the most significant influence on the braking distance. The larger the diameter, the greater the braking moment resulting so that the stopping distance becomes shorter. The number of holes in the disc also plays a role in heat dissipation because the holes enlarge the heat dissipation area. However, the increase in the number of holes tends to slightly increase the braking distance due to a reduction in the area of frictional contact field. The most optimal configuration is found on a 260 mm diameter disc with 42 holes, which results in the shortest braking distance of 8.25 meters and the lowest temperature rise of 4.47°C.  Statistical analysis using Two-Way ANOVA confirmed that the diameter and number of holes had a significant effect individually, but there was no significant interaction between the two. These findings confirm that the selection of the right disc dimensions is critical to improving braking performance, thermal efficiency, and rider safety.

This research develops an automated temperature control system for water heaters, that is both efficient and stable, driven by the need for energy-saving heating solutions, particularly for marine applications. The main objective was to create an automatic system capable of maintaining water temperature within an optimal range while maximizing energy efficiency through the use of thermal storage materials. The methodology involved an on-off control system based on a microcontroller as the main controller, capable of processing temperature sensor data in real time. This system intelligently activates and deactivates the heater to keep the water temperature stable. Paraffin wax was used as a latent heat storage medium, playing a crucial role in gradually storing and releasing thermal energy to support temperature stability. An automatic water heater system based on the ESP32 microcontroller with an on-off control mechanism was successfully designed using paraffin wax combined with silica sand as a thermal storage medium. The addition of silica sand significantly enhanced heat conductivity and temperature stability. Test results showed a substantial reduction in energy consumption, with daily savings reaching Rp12,762.88, equivalent to 67% of total daily energy costs. Over a one-year period, the total savings amounted to Rp4,658,103.20, demonstrating that the paraffin wax–silica sand combination is highly effective in improving energy efficiency and reducing long-term operational costs.

This study aims to analyze the thermal performance of the heating system in a small-scale plastic bolt molding machine using LDPE material, in order to determine process parameters that are efficient while maintaining product quality. The method used includes experimental testing at two set-point temperatures (90 °C and 120 °C), measurement of melting time and feed mass per cycle, as well as heat balance calculations separating the contributions of conduction, convection, and radiation on the barrel heated by a band heater. In addition, the power/energy requirement per cycle and productivity projections based on hopper capacity were calculated. The results show that increasing the set-point from 90 °C to 120 °C accelerates melting from ±240 s to ±180 s (≈25% faster). Heat transfer analysis confirmed the dominance of conduction (≈329.7 W at 90 °C and ≈471 W at 120 °C), while convection and radiation contributions were much smaller; the total system heat rate was ≈342.7 W (90 °C) and ≈490.8 W (120 °C). The discussion highlights the process trade-off: higher set-points increase production rate and mold filling quality (due to lower melt viscosity), but may raise energy consumption per cycle and require tighter mold temperature control to limit shrinkage/warpage. The practical implications for SMEs are the need for efficiency strategies based on barrel insulation, heater contact area optimization, and correlation of temperature-time settings with quality and energy consumption targets. This study concludes that controlled temperature and heating duration, supported by simple yet targeted thermal design, can improve cycle time consistency, dimensional precision, and energy efficiency in small-scale plastic bolt molding machines.

This study aims to analyze the effect of transformer oil purification on oil breakdown voltage and evaluate its benefits in maintaining transformer performance and reliability. Oil purification is a crucial preventive maintenance step to preserve insulation quality and prevent operational failures caused by reduced dielectric properties. The study was conducted through several stages, including data collection, oil purification, measurement of breakdown voltage before and after purification, and evaluation of results. Data collection involved measuring the oil’s electrical properties according to SPLN 49-1:1982 and observing results using a Break Down Voltage (BDV) test. Purification of a Trafindo 400 kVA transformer was performed through visual inspection, connecting the inlet and outlet hoses to the purification machine, and circulating the oil until the breakdown voltage met the required standards. Results indicated that the oil breakdown voltage before purification was below standard due to reduced insulation quality caused by water contamination, charcoal particles, thermal degradation, and dissolved gases that weakened dielectric properties. Additional factors such as electrical stress, mechanical stress, and excessive loading also contributed to insulation deterioration. After purification, the oil breakdown voltage increased significantly to meet the standard of >30 kV/2.5 mm, demonstrating that purification effectively restores the oil’s insulating capacity and supports optimal transformer performance. Analysis confirms that the transformer oil remains suitable for use, and routine annual purification is recommended to maintain reliability, efficiency, and operational performance. This study highlights oil purification as an effective preventive measure for transformer stability, extending operational life, and reducing the risk of insulation failure. The findings provide valuable guidance for transformer maintenance in the electricity industry, ensuring safe and optimal long-term operation.

This study analyzes the effectiveness of implementing predictive maintenance (PdM) on the final drive components of the Komatsu PC200-8 unit at PT. Antareja Mahada Makmur, Site PT. Multi Harapan Utama, East Kalimantan, in an effort to reduce downtime and operational losses. Before the implementation of PdM in 2022, there were 12 repair cases for the final drive with a total downtime of 772.1 hours, repair costs amounting to IDR 310.6 million, rental income loss of IDR 208.03 million, and total losses of IDR 518.63 million. In 2023, during the PdM transition phase, the number of cases decreased to 4, with a total loss of IDR 252.05 million, although downtime remained high (714.6 hours) due to the limited scope of PdM implementation on certain units and components. In 2024, with full PdM implementation, the number of repair cases decreased to 5, with total downtime of only 96 hours and losses of IDR 45.75 million. The cost of PdM implementation for the year was only IDR 21.9 million. As of July 2025, no further damage to the final drive has been recorded, demonstrating a significant improvement in equipment reliability. The reduction in total losses from 2022 to 2024 amounted to IDR 472.88 million, indicating PdM’s effectiveness in avoiding significant costs through condition monitoring methods such as oil analysis, magnetic plug rating, thermal inspection, and oil leak testing (floating seal). The findings of this study confirm that PdM is effective in reducing downtime, repair costs, and enhancing asset management in the mining sector. It also improves equipment reliability and overall operational efficiency, proving PdM to be a successful strategy in reducing losses, increasing productivity, and supporting the sustainability of company operations.

The use of palm oil waste as boiler fuel is one of the innovative solutions in supporting the use of renewable energy while reducing the environmental impact of palm oil industry waste. Waste such as palm shells, mesocarp fibers, and empty oil palm bunches have high energy potential through direct combustion and other thermal technologies. This study aims to evaluate the potential use of palm oil waste as boiler fuel based on its calorific value, combustion efficiency, and environmental impact. The methods used include analysis of the physical and chemical characteristics of waste, boiler performance tests, and exhaust gas emission evaluation. The results show that palm oil waste has a high calorific value (15–20 MJ/kg), which makes it an efficient alternative fuel. In addition, the use of this waste is able to reduce dependence on fossil fuels while minimizing carbon emissions, thereby supporting the greenhouse gas emission reduction target. From an operational perspective, the use of palm oil waste in industrial boilers can increase combustion efficiency by up to 75–85%, depending on fuel conditions and boiler design. This makes palm oil waste not only economically valuable, but also strategic in supporting the transition to clean energy. Another advantage is that waste management becomes more targeted, because solid waste that is usually only an environmental burden can be reused as an energy source. However, some of the challenges that need to be considered include relatively high ash levels, the potential for corrosion in boiler equipment, and the need for emission control technology to comply with environmental standards. With the right mitigation strategy, palm oil waste can be processed into sustainable and environmentally friendly energy.