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The outbreaks of infectious diseases that spread across countries have generally existed for centuries. An example is the occurrence of the COVID-19 pandemic in 2020, which led to the loss of lives and economic depreciation. One of the essential ways of handling the spread of viruses is the discovery and administration of vaccines. However, the major challenges of vaccination programs are associated with the vaccine cold chain management and cold storage facilities. This paper discusses how vaccine cold chain management and cold storage technology can address the challenges of vaccination programs. Specifically, it examines different systems for preserving vaccines in either liquid or frozen form to help ensure that they are not damaged during distribution from manufacturing facilities. Furthermore, A vaccine is likely to provide very low efficacy when it is not properly stored. According to preliminary studies, the inability to store vaccine properly is partly due to the incompetency of many stakeholders, especially in technical matters. The novelty of this study is to thoroughly explore cold storage technology for a faster and more comprehensive vaccine distribution hence it is expected to be one of the reference and inspiration for stakeholders.

Biodiesel is a clean energy biofuel which can be produced from waste cooking oil under transesterification and purification process by dry washing method. Dry washing purification method using hydrate magnesium silicate as a cleaning agent will improve the quality and yield of the biodiesel. This research used Response Surface Methodology with Box Behnken Design (BBD) consisting of 3 independent variables i.e. concentration of hydrate magnesium silicate, temperature and time to find the optimum condition in producing biodiesel yield. The optimum result showed that the biodiesel yield ranged between 85-94.50% where the maximum yield of 94.50% was produced under an adsorbent concentration of 2%, operating temperature of 55 0C and 20 minutes of treatment.

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.

Concentrated photovoltaic cell (CPV) had gained much attention recently due to high efficiency at a competitive cost. However, efficiency of CPV is inversely proportional to the temperature. Hence, it is important to reduce the maximum temperature and variation of temperature across the CPV. Metal foam with its high specific surface area, thermal conductivity and tortuous flow path to promote mixing is an ideal candidate for thermal management for CPV. However, the thermal performance of the metal foam may drop from upstream to downstream and lead to poor cooling performance near the outlet. In this study, functionally graded metal foam is attached on the CPV to extract the heat generated. Functionally graded aluminum foam with gradual variation porosity are modelled to investigate the thermal performance and flow field using computational thermal fluid dynamics analysis. Heat transfer correlation, permeability and resistance loss coefficient are extracted from the literature and used in the simulation. The results showed that functionally graded metal foam with gradual reducing porosity offered a better temperature uniformity for the CPV. Therefore, this approach will further extend the cycle life as well as improve the overall efficiency of the CPV.

Waste Heat Recovery System (WHRS) technology, e.g., Organic Rankine Cycle (ORC) has been explored as a solution to the increase in geothermal potential, possibly applied in binary or combined form, as a single-flash plant. This approach utilizes waste brine obtained from the separator. The purpose of this study, therefore, was to determine the performance of R134a refrigerant on ORC systems, using scroll-expander. The experiment was conducted with motor different frequency, at 7.5 Hz, 10 Hz, 12.5 Hz, 15 Hz, 17.5 Hz, and 20 Hz, evaporator temperature regulation of 95 °C, condenser at 10 °C, and an initial working fluid pressure of 5 bar. The results showed modifications in the ORC system performance with scroll-expander, alongside the motor frequency, which influenced the net power and energy efficiency. In addition, the maximum speed produced by the expander was 505.8 rpm, while the highest for energy efficiency achieved from the system was 3.17%, at a motor frequency of 7.5 Hz, with a resulting net power of 584.5 Watt.

Indonesia is well-known for its reputation for possessing the world's largest geothermal potential, which has been characterized by high temperature geothermal resources' concentration. The geothermal energy potential of Indonesia has been estimated to be 28,617 MW, which is about 40% of the world's geothermal potential. However, only about 4.5% is being utilized as electrical energy supply in this country. This paper comprises the Indonesian geothermal resources, based on their capability of doing work and efficiency. In this study, currently operating geothermal power plants in Indonesia have been classified, based on the exergy concept and the Specific Exergy Index (SExI). The results of SExI values show that nine geothermal fields are classified as high exergy resource with their SExI values exceeding 0.5, and two remaining power plants with SExI values between 0.05 and 0.5 are classified as medium geothermal resources.

Several countries around the world currently use the conventional method to produce salt but this has been discovered to have some disadvantages such as dependence on rainfall, air humidity and temperature, land, sunlight, and wind speed. This, however, makes the production dependent on the season of a region such that a high rainfall leads to a decrease in production. Meanwhile, it is possible to produce salt by separating the particles from their water and creating a droplet forced by airflow and heat convection. Therefore, this research was conducted to examine a salt production process using the spraying and heating method which involves the application of a nozzle assisted by a blower and heater. The results showed the use of a nozzle and blower affected the salt production time and weight. The best yield and time were found at 0.1 mm nozzle with 1 h 50 min and 1067.67 g weight respectively while 4.9 m/s blower speed had 1026 g weight in 2 h 5 min. It is also important to note that the salt produced using this method is more white and smoother than using conventional methods.

Indonesia has the potential of saving from 10% to 30% of energy in the commercial sector which consists of trade, hotels, restaurants, finances, government agencies, schools, hospitals, and communications. By simultaneously serving as building envelope material and power generator, BIPV systems can represent savings in the cost of materials and electricity. It reduce the use of fossil fuels and emission of ozone depleting gases, and also add architectural interest to buildings. However, the temperature rise poses a challenge for BIPV, given that it manifests itself in electrical efficiency and overheating. The experiments present in this study aim at understanding the behavior of the PV-PCM systems in realistic outdoor uncontrolled conditions to determine how effective they are. In addition, the PV-PCM systems were tried in the low latitude and hot climate of Banda Aceh, Indonesia. Experiments were conducted outdoors at the Engineering Faculty in Syiah Kuala University, located in Banda Aceh, Indonesia (05:57 N, 95.37 E). In this study, both paraffin wax and beeswax were used as a phase change material. The final results showed that the electrical efficiency of PV panels without PCM is ranged between 6.1% and 6.5%. While for PV panels with PCM the efficiency is ranged at 7.0–7.8%. This proved that the process of water cooling is capable of increasing the efficiency of PV panels. Keywords: PV, Phase change material, Temperature, Efficiency

Thermal management system is crucial for a Lithium-ion battery pack as cycle life, driving range of electric vehicle, usable capacity and safety are heavily dependent on the operating temperature. Optimum operating temperature of Lithium-ion battery pack is about 25–40 °C. Power availability of the battery pack may differ according to the operating temperature. Although air cooling is the simplest and cheapest cooling solution, the cooling capacity is still limited by the low specific heat capacity. This will cause large variation of temperature of cells across the battery pack. In this study, mist cooling is proposed for battery pack thermal management system. Experiments and numerical simulations are conducted to investigate the thermal performance of conventional dry air cooling and mist cooling. Simulation results are then validated with the experimental data. The simulation results show that mist cooling can offer lower and more uniform temperature distribution compared to dry air cooling. Mist cooling with mass flow rate of 5 gs−1 and 3% mist loading fraction is sufficient to ensure the surface temperature of the battery module maintained to below 40 °C. Therefore, mist cooling is a potential solution for the thermal management system of Lithium-ion battery pack.

The thermal decomposition method has been able to convert of real municipal solid waste (MSW) into Bio-Crude Oil (BCO) which is mainly contained hydrocarbon fuel such as light oil (gasoline) and heavy oil (diesel). By this method, sustainable MSW management and energy problem can be considered. Hence, this research was conducted the pyrolysis experimental to BCO production from the real MSW under thermal and catalytic pyrolysis at 400 °C and 60 min for time reaction. To increase the BCO yield in this study, the natural activated zeolite as a catalyst was employed. BCO was analyzed by Gas chromatography–mass spectrometry (GC–MS) which it can be used to identify carbon number range by percentage of peak areas. It was found that the catalytic pyrolysis has performances better than the thermal pyrolysis. Both of thermal and catalytic pyrolysis were the produce of BCO around 15.2 wt% and 21.4 wt% respectively with the main organic components are gasoline and diesel. Furthermore, paraffin and olefin fraction are major species in the gasoline and diesel. It can be concluded that the content of MSW and their processes has an impact on the fuel produced. In the thermal cracking produce BCO with higher content in the gasoline range. More plastic in MSW is also produce more gasoline while more biomass produces more in diesel range.

This method of combining thermodynamic and silica scaling analysis aims to improve efficiency, power output and sustainability in geothermal power plants which suffer from high concentration of silica. The proposed method was employed in an analysis of the Dieng geothermal power plant. The process starts with a performance evaluation of the existing power plant system, which is comprised of many components where losses of both energy and exergy occur. Once the performance of the existing plant has been evaluated, optimization of operating parameters can be applied to maximize its power output without the expensive addition of any new components. The process then continues with the development of scenarios with the power plant’s design, seeking potential methods to improve its performance. In these scenarios, the plant is expanded into a double flash system, single flash-binary and double flash-binary. Silica scaling behavior models are then applied to determine which is the best scenario for development. It was found that a double flash system is the best expansion scenario for Dieng Geothermal Power Plant. This scenario produces a high power output of 29,155 kW and the lowest excess deposit of silica at 899 ppm. Although this scenario produces lower power output than the double flash-binary system, it has less negative impact from silica scaling. By introducing this system, the company can obtain additional power output of 4855 kW.

Dieng geothermal power plant is one of the Geothermal plants located in Indonesia with a total estimated potential of 400 MWe. The reservoir is characterized by water-dominated with 240 to 333°C temperature. Recently, the company operated one unit of single-flash system with a capacity of 60 MW. To improve its capacity, unit expansion of unit 2 and 3 are designed with each capacity of 60 MW. Apart from this expansion, another effort is optimizing the existing plant. It can be conducted with a thermodynamic approach using energy and exergy analysis. Therefore, this study aims to evaluate and optimize the existing geothermal power plant using energy and exergy analysis. With the latest data obtained, the results show that the exergy value of production wells is around 106,515 kW. The electricity production with the system is around 40,680 kW, resulting in an exergy efficiency of about 38.19%. Furthermore, the optimization is carried out on the turbine because it shows the greatest irreversibility of 11,217 kW. Optimization is done by varying the incoming turbine pressure. These results indicate that higher inlet pressure increases irreversibility and lowers energy efficiency. Furthermore, the optimum inlet turbine pressure is achieved at 5.5 bar with the maximum change depending on the ambient temperature.

This paper investigates a fluidized bed boiler used in an ethanol production plant. The boiler uses biogas fuel produced by the waste system of the distillation unit within this ethanol plant. Using Engineering Equation Solver (EES), a mathematical model is developed by employing the exergy analysis. Before the study was undertaken, initial operating data of the components in the plant was collected. The results show that the boiler system has an overall efficiency of 68.238 %. The exergy efficiency in each component was also calculated. The evaporator and heat exchanger have the lowest efficiency at 45.97% and 28.96%, respectively. The efficiencies of the other components are 61.41% for the pump water pit, 54.42% for the soft water tank and 66.39% for the de-aerator.

Li-ion battery is widely used as an energy storage system in electric vehicles and it has several advantages such as long cycle life, high energy density, superior usable capacity, low self-discharge rate and fast charging capability. However, the optimum operating temperature window of the battery is limited to 25 °C - 40 °C. Actual performance can deviate substantially if it is operated at higher or lower temperatures. Although electron and ion mobility is increased at high temperature due to low internal cell resistance, It may initiate irreversible chemical reactions which can cause thermal runaway. At temperature below 0 °C, the cell’s internal resistance is high and the performance starts to deteriorate due to Lithium plating. Therefore, this highlights the importance of the thermal management system for the Li-ion battery. In this study, thermal performance of the mist cooling was studied and compared with conventional dry air cooling using computational fluid dynamic simulation. Simulation results are then validated with experimental data and the correlation between Nu and Re was derived. From this study, it is shown that mist flow rate of 0.37 gs-1 and air velocity of 2 ms-1 is sufficient to maintain the surface temperature of dummy battery below 40 °C. Hence, mist cooling can be used as a new cooling solution for the Li-ion battery.

Carbon Capture and storage may contribute as much as one-fifth of the necessary reductions to meet the IEA’s emissions goals for 2050. CCS is one of the only technologies that reduces the carbon impact of “business as usual,” preventing CO2 from burning fossil fuels and certain industries from entering the atmosphere. Japan has geological, regulatory, and financial advantages encouraging investment in CCS and several demonstration projects are already underway. Using a Markel-Times system model, long-term road map results are presented for Japan’s future energy mix and CCS capacity. In the short term until 2030, import prices of fossil fuels are expected to increase while renewable solar and wind power will grow rapidly. The role of nuclear power is more debatable in the wake of the Fukushima disaster, but the projection anticipates at least some nuclear power to be used in the coming decades. Two industries are modeled for CCS, steel production and cement manufacture. Launched by start-up investments, CCS is expected to begin industrially from 2015 and could grow to capture and store more than 90 PJ of carbon from the steel industry per year and another 60 PJ from cement factories every five years.

This paper examines a simulation of Jatropha curcas shell within an entrained flow gasifier to predict the composition of gaseous product. Since there is no available data of Jatropha shell experiment, we validated the model using other biomass: rice husk and sawdust. The validation results showed that the model agreed with the experimental data of rice husk and sawdust. Furthermore, the same model is applied for Jatropha curcas properties data. From this simulation, we obtained that carbon monoxide (CO) and hydrogen (H2) increased when reactor temperature was raised. Meanwhile, carbon dioxide (CO2) and methane (CH4) decreased. Since the simulation is not validated directly with Jatropha shell experimental data, error may come because of this situation. Therefore, we applied the Mean Error Approach (MEA) and produced a range of gas products through Jatropha shell in a simulation. The MEA data shows that methane (CH4) has the highest mean errors with both sawdust and rice husk, at values of 0.8776 and 0.6115, respectively. Carbon monoxide (CO) on the other hand, has the lowest error. When we then apply this MEA to Jatropha shell simulation result, it shows that the range of carbon dioxide (CO2) produced by Jatropha shell gasification has a composition ranging from 40.54 to 52.32% at a temperature of 1000 °C. The composition ranges of hydrogen (H2), carbon dioxide (CO2), and methane (CH4) gases are 27.07–35.91%, 5.43–28.29%, and 0.49–9.96%, respectively.

In this paper thermal and hydraulic optimization of water to water chevron type plate heat exchanger is presented. The optimization is performed using the multi objective genetic algorithm in MATLAB optimization environment. Constrain matrix is a set of different geometrical parameters of plate heat exchanger within the logical bounds. The two objective functions are pressure drop of hot side and heat transfer. Due to conflicting nature of these objective functions, no single solution can satisfy both of the objective function simultaneously. The increase in heat transfer will results in increase in pressure drop, therefore, optimization results are presented as Pareto Front. Multi objective genetic algorithm tool was employed to find a set of optimum solution which was trade-off between pressure drop and heat transfer. At the end, sensitivity analysis was performed to analyse the effect of geometrical parameters of heat exchanger on thermal and hydraulic performance. The sensitivity results show that the heat transfer and pressure drop are greatly affected by the vertical port centre distance, plate spacing and number of thermal plates.

The main objective of this research is to investigate the effect of attaching nozzle lens with difference diameter and number of blades in non-twisted NACA 4415 on the power output of the Horizontal Axis Wind Turbine (HAWT). The Artificial of low wind speed were used in this experiment at 2.5 m/s, 3.5 m/s, and 4.5 m/s. The result shows that the lenses increase the power output. The lens diameter is directly proportional to the rotor speed and TSR of the turbine. In the difference number of blades, the three-blades turbine consistently generates the highest power output compared to two-blades and four-blades turbines. The evidence has established that nozzle lenses and three-blades turbine can successfully increase the efficiency of wind turbines in areas where wind speed is low.

Japan's energy consumption derives mostly from fossil fuels, which are un-secure and release a much greenhouse gas emissions. To meet goals of reducing GHG, hydrogen gas can be utilized in power generation in hydrogen fired and firing / co-combustion power plants. This paper analyses the impact of hydrogen in the power generation sector using the MARKAL-TIMES Japan optimization model framework. Two models are used: a base scenario without hydrogen and hydrogen scenario in which hydrogen is supplied from 2020 onwards. In the hydrogen scenario, other processes which are normally supplied by natural gas are reduced because the gas is instead used to generate power. Adding hydrogen to the energy supply leads to a decrease in projected use of fossil fuels. The hydrogen scenario produces fewer emissions than the base scenario; by 2050, the hydrogen scenario's estimated 388 metric tons of CO 2 emissions is over 250 tons less than the base scenario's emissions of 588 metric tons.

Data centers have become one of the most important elements of the Industrial Revolution 4.0. However, conventional data centers face the problem of electricity consumption, with 40% being used for the cooling systems. This led to the proposed development of immersion cooling as one of the methods to solve the current data center cooling system issues. This paper, therefore, was aimed at determining the factors affecting the immersion cooling performance using mineral oil. The experiment was further conducted by creating an immersion cooling box and running the server by loading the software. The contribution and effect of each factor were also determined through the use of the Taguchi Method with Orthogonal Array L8. The performances measured include the CPU temperature and Energy Consumption using the effect of the inlet-outlet location, flowrate and cooling fan speed as the Taguchi factors. The results showed that the CPU temperature was affected by cooling fans with 71.278% and energy consumption by 75.034%.

Promoting electricity supply in remote areas and islands by developing power plants using organic waste biomass fuel, is a strategic effort in increasing energy supply. This study aimed at investigating the characteristic of gasification toward air fuel ratio variation, especially the temperature, lower heating value and tar content on the gasification performance with multi integrated gas cleaner systems (IGCS) used as producer gas purification unit. The plant was built with downdraft gasifier and multy IGCS which includes cyclones, rectangular venturi scrubbers, and rotary separators. The experimental investigation were carried out with air fuel ratio parameters at 0.48, 0.5, 0.54, scrubbing water discharge at 1.26, 2.62, 3.33 l/min, and 0.9 rotary separator using a suction speed of 3.4, 4.4 m/s. All parameters were intended to produce clean gas with high heating value, low tar and impurities. The experimental results showed air fuel ratio 0.54 produced the largest gas at lower heating value of 8500 kJ/Nm3, however the tar content is relatively high at 3788.1 mg/ m 3 . The installation of multi IGCS reduced the tar to 210.45 mg/ m 3 with water discharge of 3.33 l/min and 4.4 m/s suction speed. Therefore, the electrical power generated was 100 W.

This study aims at comprehensively describing the ups and downs of vocational education in Indonesia, which includes its history, development, opportunities, and challenges. Researches in this field are rarely conducted, but necessary to be revealed in the midst of the incessant criticism. This study uses a qualitative approach with a cross-sectional design. However, due to the complexity of the variables and the difficulty in accessing sources in their original form (primary sources), this study utilizes policy documents and relevant research work. Data analysis has been added, including: inductive, deductive, and meta-analysis. Data were obtained from principals, students and teachers of vocational high schools (SMK). Furthermore, purposive sampling was selected to obtain data, giving a sample population consisting of 44 principals, 152 teachers, and 202 students. Purposive sampling was chosen due to its in-depth understanding on vocational education. However, not all principals and teachers in Indonesia are vocational based. Data were obtained from experts in the field of vocational education through interview, observation, documentation, and questionnaire guidelines compiled and validation. The results showed that vocational education in Indonesia has been in existence before the country gained independence, and after reform. However, before independence, the Netherlands organized Vocational Education, known as the Bandung Institute of Technology (ITB), which is still developing. Vocational education before independence was divided into 4 areas of expertise, namely feminine, engineering, agriculture and trade schools. After reform in 1998, the different schools were merged into one, namely vocational school (SMK) having 142 spectrums of skills. Furthermore, the development of vocational education was changed in 2008. The Indonesian government changed the ratio of senior high schools: vocational schools from 70%: 30% to 30%: 70%. The establishment of a new school was not balanced with a feasibility study, and this resulted in graduates finding it difficult to get a job. They learned approaches which tended to be theoretical and less relevant in the labour market. In addition, 74% of students were bored during learning due to the numerous social lessons. Some of the challenges faced were the inadequate facilities, teachers and industry support. However, the clear regulation on the industry's role is one of the important solutions. Strong industry support can be applied and vocational graduates have the competence in accordance with the needs of the labour market.

The performance of the vortex tube is low compared to a conventional heat pump engine based on Freon refrigerants, and therefore, there is a need for an experiment on how to improve its efficiency. This data article aims to analyze the effect of the new vortex tube design on cold temperature (Tc), hot temperature (Th), delta cold temperature (ΔTc), delta hot temperature (ΔTh), heat transferred as cooling effect ( Q ˙ c ) , heat transferred as heating effect ( Q ˙ h ) , isentropic efficiency as cooling effect (ηisc), isentropic efficiency as heating effect (ηisc), the coefficient of performance refrigeration (COPref), and coefficient of performance heat pump (COPh), which is tested based on pressure and fraction variations. The data were obtained from the experimental measurements. Data were collected at conditions with temperature controlled at 27 ± 0.1°C. All measuring instruments were supposed to be consistent for at least 5 min for data to be collected, although retrieval was conducted 4 times.

We investigated proposed design of a double-flash system and compared it to the existing single-flash power plant in Dieng, Indonesia, which uses waste brine from a high pressure separator. The performance of the double-flash system was evaluated using the second law of thermodynamics, and this was based on energy and exergy analyses. The Engineering Equation Solver (EES) was used to solve the relevant mathematical equations. Our results indicate that the double-flash design is interesting for application in Dieng since the power output would increase by 19.97%. Moreover, the precipitation system to avoid silica deposition in the injection well does not have to change much. Therefore, the building costs associated with the new double-flash system would be minimal. The available exergy from the reservoir is 66,204 kW based on the enthalpy determined by TFT (Tracer Flow Test) measurements. The single-flash power plant has a net power output of 23,400 kW with a second law efficiency of 36.7%. In the double-flash design, components such as a LPS, a second purifier and an HPT would be added to the plant. Furthermore, our calculations indicate that the power plant's output and second law efficiency would increase to 29,155 kW and 44.04%, respectively. The waste brine disposed of using this precipitation system would decrease by 8.22% at 5443 kW.