Performance of beeswax phase change material (PCM) and heat pipe as passive battery cooling system for electric vehicles

© 2020 The Authors. Increasing greenhouse gas (GHG) emissions in the atmosphere and the scarcity of fossil fuel sources have encouraged car manufacturers to develop more environmentally friendly electric vehicles (EVs). The technology advancements of EVs - those with battery systems in particular - have increased their travel distances. Therefore, increasing and maintaining the battery capacity is a key concern in the development of sustainable EVs. In this study, passive cooling systems were constructed with a heat pipe and phase change material (PCM), and their performances were investigated with battery simulators. The aim was to determine the effectiveness of the cooling system and to identify the optimal PCM (beeswax or Rubitherm RT 44 HC) for a temperature range of 25-55 °C. The use of a heat pipe could decrease the battery temperature by 26.62 °C under a 60 W heat load compared to the case without passive cooling system. Furthermore, the addition of RT 44 to a heat pipe resulted in a maximal temperature decrease of 33.42 °C. Thus, an RT 44 HC is more effective than beeswax because its melting temperature lies within the recommended range of the battery working temperature, and its latent heat allows the absorption of more heat compared to beeswax

Techno-Economic Analysis and Optimisation of Campus Grid-Connected Hybrid Renewable Energy System Using HOMER Grid

This study aimed to conduct a techno-economic performance and optimisation analysis of grid-connected PV, wind turbines, and battery packs for Syiah Kuala University, situated at the tip of Sumatra island in the tsunami-affected region. The simulation software Hybrid Optimisation Model for Electric Renewables (HOMER) was used to analyse and optimise the renewable energy required by the institution. The methodology began with the location specification, average electric load demand, daily radiation, clearness index, location daily temperature, and system architecture. The results revealed that the energy storage system was initially included in the simulation, but it was later removed in order to save money and optimise the share of renewable energy. Based on the optimisation results, two types of energy sources were chosen for the system, solar PV and wind turbine, which contributed 62% and 20%, respectively. Apart from the renewable energy faction, another reason for the system selection is cost of energy (CoE), which decreased to $0.0446/kWh from$0.060/kWh. In conclusion, the study found that by connecting solar PV and wind turbines to the local grid, this renewable energy system is able to contribute up to 82% of the electricity required. However, the obstacle to implementing renewable energy in Indonesia is the cheap electricity price that is mainly generated using cheap coal, which is abundantly available in the country

Role of optimization algorithms based fuzzy controller in achieving induction motor performance enhancement.

Three-phase induction motors (TIMs) are widely used for machines in industrial operations. As an accurate and robust controller, fuzzy logic controller (FLC) is crucial in designing TIMs control systems. The performance of FLC highly depends on the membership function (MF) variables, which are evaluated by heuristic approaches, leading to a high processing time. To address these issues, optimisation algorithms for TIMs have received increasing interest among researchers and industrialists. Here, we present an advanced and efficient quantum-inspired lightning search algorithm (QLSA) to avoid exhaustive conventional heuristic procedures when obtaining MFs. The accuracy of the QLSA based FLC (QLSAF) speed control is superior to other controllers in terms of transient response, damping capability and minimisation of statistical errors under diverse speeds and loads. The performance of the proposed QLSAF speed controller is validated through experiments. Test results under different conditions show consistent speed responses and stator currents with the simulation results

Effect of injection timing and injection duration of manifold injected fuels in reactivity controlled compression ignition engine operated with renewable fuels

In the current work, an effort is made to study the influence of injection timing (IT) and injection duration (ID) of manifold injected fuels (MIF) in the reactivity controlled compression ignition (RCCI) engine. Compressed natural gas (CNG) and compressed biogas (CBG) are used as the MIF along with diesel and blends of Thevetia Peruviana methyl ester (TPME) are used as the direct injected fuels (DIF). The ITs of the MIF that were studied includes 45°ATDC, 50°ATDC, and 55°ATDC. Also, present study includes impact of various IDs of the MIF such as 3, 6, and 9 ms on RCCI mode of combustion. The complete experimental work is conducted at 75% of rated power. The results show that among the different ITs studied, the D+CNG mixture exhibits higher brake thermal efficiency (BTE), about 29.32% is observed at 50° ATDC IT, which is about 1.77, 3.58, 5.56, 7.51, and 8.54% higher than D+CBG, B20+CNG, B20+CBG, B100+CNG, and B100+CBG fuel combinations. The highest BTE, about 30.25%, is found for the D+CNG fuel combination at 6 ms ID, which is about 1.69, 3.48, 5.32%, 7.24, and 9.16% higher as compared with the D+CBG, B20+CNG, B20+CBG, B100+CNG, and B100+CBG fuel combinations. At all ITs and IDs, higher emissions of nitric oxide (NOx) along with lower emissions of smoke, carbon monoxide (CO), and hydrocarbon (HC) are found for D+CNG mixture as related to other fuel mixtures. At all ITs and IDs, D+CNG gives higher In-cylinder pressure (ICP) and heat release rate (HRR) as compared with other fuel combinations

A comparative study of virgin coconut oil, coconut oil and palm oil in terms of their active ingredients

© 2020 by the authors. This research aims to study the unique factors of virgin coconut oil (VCO) compared with coconut oil (i.e., coconut oil processed through heating the coconut milk and palm oil sold on the market). Its novelty is that it (VCO) contains lactic acid bacteria and bacteriocin. Lauric acid content was analyzed by the Chromatographic Gas method. Isolation of lactic acid bacteria (LAB) was conducted by the dilution method using MRSA + 0.5% CaCO3 media. Iodium number, peroxide, and %FFA were analyzed using a general method, and isolation bacteriocin by the deposition method using ammonium sulfate. In addition, macromolecular identification was conducted by 16S rRNA. VCO was distinguished by a higher content of lauric acid (C12:0) 41%-54.5% as compared with 0% coconut and 0, 1% palm oil, respectively. The VCO also contains LAB, namely Lactobacillus plantarum and Lactobacillus paracasei, and can inhibit the growth of pathogenic bacteria, such as Pseudomonas aeruginosa, Klebsiella, Staphylococcus aureus, S. epidermidis, Proteus, Escherichia coli, Listeria monocytogenes, Bacillus cereus, Salmonella typhosa and bacteriocin. Comparison with VCO is based on having a high content of lauric acid, 54%, and LAB content. The difference between VCO and coconut oil and palm oil is fatty acids. In VCO there are lauric acid and stearic acid, namely lauric acid VCO (A) 54.06%, VCO (B) 53.9% and VCO (C) 53.7%. The content of stearic acid VCO (A) is 12.03%, VCO (B) 12.01% and VCO (C) 11.9%. Coconut oil contains a little lauric acid, which is 2.81%, stearic acid 2.65% and palmitic acid 2.31%. Palm oil can be said to have very little lauric acid, namely in palm oil 1, 0.45%, and even in palm oil 2, 0%; in turn, palmitic acid palm oil 1 has 2.88% and palm oil 2 palmitic acid has 24.42%

The effect of hybrid savonius and darrieus turbine on the change of wake recovery and improvement of wind energy harvesting

© 2018 Institut za Istrazivanja. All rights reserved. The energy crisis encourages the development of renewable energy; one of the potential renewable energy is wind. In the field of wind turbine there is a two-way development of the utilization of wind energy, first by making a large wind turbine, the second by making a wind farm energy with a relatively small wind turbine.This hybrid VAWT wind turbine (Sultan Wind Turbine) is designed to work optimally on a farm array, on a wind turbine farm array will always cause a wake effect that will reduce overall wind turbine and farm array performance, an investigation with a CFD simulation is required to predict how far the wake effect will be before farm array build.The use of simulation software has been widely used to predict the effects of this wake, and experiments in the laboratory have also been done to predict the effects of a wake as well.This study'spurpose is to predict the distance area of the recovery wake behindthe wind turbine, this distance which will be the reference distance between wind turbine units and determining the density of the turbine in a farm. Simulation using Computational Fluid Dynamics (CFD), with a method of Multi Frame Reference (MRF). Analysis using descriptive and inferential method in statistics such as mean, Kolmogorov-Smirnov Z and KruskalWalis test.From the analysis of simulation results and data processing descriptively and analytic statistic, it can be concluded from the data given, the distance of x/D=4, wind speed has recovery to the value near the input speed and no significant change to x/D= 9. Then it can be concluded that the distance between two windturbines that can be used is a distance of 3.6 meters.These data suggest that the hybrid farm array VAWT savonius and darrieus have a higher power density compared to HAWT. From this power density calculation the hybrid VAWT has a greater electrical potential up to 300 percent compared to the HAWT farm array

Life cycle assessment, energy balance and sensitivity analysis of bioethanol production from microalgae in a tropical country

© 2019 Elsevier Ltd Overuse of petroleum and ongoing carbon-di-oxide (CO2) rise in the air of Brunei Darussalam has been emerged as a major environmental concern in this country. To resolve this issue, a comprehensive life cycle assessment (LCA) of alternative biofuel, bioethanol production from microalgae was demanded for realistic implementation. Therefore, LCA of bioethanol production from microalgae in terms of CO2 emission and energy balance was investigated based on the scenario of industrial-scale in Brunei Darussalam. This study demonstrated that 220 tons microalgae biomass was cultivated on 6 ha offshore lands for commercial bioethanol generation. The annual outcome of this commercial bioethanol plant has revealed net CO2 balance 218.86 ton. From the energy perspective, this study manifested itself as favourable with net energy ratio, 0.45 and net energy balance, −2749.6 GJ y−1. Apart from CO2 balance and energy generation aspect, the project demanded low water and land footprints. For photobioreactor cultivation, water and land footprints were 2 m3 GJ−1 and 2 m2 GJ−1, respectively as well as for open pond approach, they were 87 m3 GJ−1 and 13 m2 GJ−1, respectively. The project also presented microalgae growth supplements (phosphorus and nitrogen) accumulation possibilities from wastewater of manure and industries which is another positive aspect for benign environment. Overall, the commercial plant presented low CO2 emission, low land and water demand for microalgae cultivation, alternative eco-friendly and cheaper nutrients sources, quite high energy generation with main product and by-products. Thus, this study projected positive impact on energy and environmental aspects of microalgae-to-bioethanol conversion

Utilizing heat pipe heat exchanger to reduce the energy consumption of airborne infection isolation hospital room HVAC system

© 2020 Elsevier Ltd The COVID-19 pandemic in early 2020 became a global issue and received substantial attention worldwide. In a hospital, airborne infection isolation (AII) room is significant to prevent the spread of the virus to patients and medical personnel. This research aims to improve the design of the HVAC system of AII room used for removing contaminated air by making physical changes through the addition of heat pipe heat exchanger (HPHE). Experiments were conducted with varying fresh air inlet temperature between 30 and 45 °C and velocity between 1.5 and 2.5 m/s with three configurations of HPHE to investigate the performance of the HVAC system in the AII room. To ensure the HVAC system with HPHE meets the AII room requirements, this study carried out a smoke test as well as pressure and hourly air volume measurement tests between the exhaust and supply air sides. The results showed that the design of ventilation coupled with HPHE could meet the standards for the AII room. The HPHE succeeded in reducing energy consumption through pre-cooling of fresh air before entering the cooling coil device, with the highest temperature difference of 9.4 °C. The highest energy recovery was 767 W at 0.080 m3/s air volume, which can handle 46% of the total HVAC system load at operating conditions and enhance the combined efficiency of the HVAC system. Based on the results, it can be concluded that the HPHE can be coupled in the HVAC system of the hospital AII room that is safe from cross-contamination which significantly reduces the energy consumption

Preparation of beeswax/multi-walled carbon nanotubes as novel shape-stable nanocomposite phase-change material for thermal energy storage

© 2018 Elsevier Ltd Development of phase-change material (PCM) as thermal energy storage for building envelopes is promising for energy utilization. However, there are two major drawbacks of PCM application, which are low thermal conductivity and high-volume reduction due to phase-change transition. One solution is to develop a shape-stabilized phase-change material (SSPCM) as a composite that is able to prevent leakage during the transition from solid to liquid. Therefore, the objective of this study is to prepare beeswax/multi-walled carbon nanotubes as form-stable nanocomposite phase-change material for thermal energy storage, based on previously unattempted methods. Beeswax was being used as PCM because of its high latent heat and multi-walled carbon nanotubes (MWCNTs) as supporting material with high thermal conductivity. There are three types of MWCNTs applied in this research: pristine MWCNTs, ball-milled MWCNTs and acid-treated MWCNTs. Beeswax/CNT composite samples were prepared with ratios of 5 and 20 wt%. Composite samples were tested from structure modification and thermal performance, including latent heat, sensible heat, melting point, solidifying point, thermal conductivity, and thermal-cycle testing for up to 300 cycles. Experimental results showed that thermal conductivity of novel shape-stable nanocomposite PCM increased by a factor of 2 and there was no significant phase transition in the melting or solidifying temperature. The high heat storage capability and thermal conductivity of nanocomposite PCM enable it to be a potential material for thermal energy storage in practical applications