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

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%

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

Scheduling controller for microgrids energy management system using optimization algorithm in achieving cost saving and emission reduction

This study deals with the development of an optimal power scheduling controller for energy management of distributed energy resources in the microgrid system. The developed optimized controller is implemented using lightning search algorithm to overcome the uncertainties of microgrid energy management and to provide an optimum power delivery to loads with minimum cost. The primary objectives of the proposed optimized controller are to: (i) develop an optimized controller for microgrids energy management, (ii) minimize the total operating cost of the distributed energy resources units, (iii) reduce the environmental emission, and (iv) solve the complicated constraint optimization problems. The proposed optimization algorithm is implemented in the modified IEEE 14-bus test system to optimize the microgrid power management schedule. The optimized controller is executed based on the real load varying conditions recorded in Perlis, Malaysia. It is observed that the optimized controller successfully reduced the amount of power consumption from 971.65 MW to 364.3 MW which in turn saving cost of RM 265432.06. The proposed scheduling optimized controller performance is compared with the recent reported work of backtracking search algorithm optimization for validation. Result shows that the lightning search algorithm based MG controller produced a cost-effective system with 62.5% of cost saving and 61.98% of carbon dioxide emission reduction which is much higher compared to with MG and backtracking search algorithm based MG optimization, respectively. The effectiveness of the proposed approach outperformed other techniques in terms of minimum total operating cost of distributed energy resources and solving complicated constraints in optimization problems

New method to synthesize mesoporous titania by photodegradation of surfactant template

Mesoporous titania has been successfully synthesized by photodegradation removal of cetyltrimethylammonium bromide as the surfactant, after slow hydrolyzation of titanium(IV) isopropoxide. Fourier transform infrared spectra proved that photodegradation has successfully decreased the peak areas of the alkyl groups from the template. The nitrogen adsorption analysis showed that the pore size and the specific surface area of the mesoporous titania were 3.7 nm and 203 m2 g-1, respectively, proving the mesoporosity of the titania obtained with the existence of the interparticle mesoporosity which was confirmed by transmission electron microscopy. Based on X-ray diffraction results, the mesoporous titania obtained was in the form of crystalline anatase phase. Furthermore, results from the diffuse reflectance ultra violet-visible spectra showed that the composition of tetrahedral titanium(IV) was more than the octahedral titanium(IV). When the mesoporous titania obtained was used as a catalyst in the oxidation of styrene, an improvement in the conversion of styrene (38%) was observed when compared to those obtained using Degussa P25 TiO2 (14%) as the catalyst

Insights into the development of microbial fuel cells for generating biohydrogen, bioelectricity, and treating wastewater

Bio-electrochemical systems, such as microbial fuel cells (MFCs), serve as greener alternatives to conventional fuel energy. Despite the burgeoning review works on MFCs, comprehensive discussions are lacking on MFC designs and applications. This review paper provides insights into MFC applications, substrates used in MFC and the various design, technological, and chemical factors affecting MFC performance. MFCs have demonstrated efficacy in wastewater treatment of at least 50% and up to 98%. MFCs have been reported to produce ∼30 W/m2 electricity and ∼1 m3/d of biohydrogen, depending on the design and feedstock. Electricity generation rates of up to 5.04 mW/m−2–3.6 mW/m−2, 75–513 mW/m−2, and 135.4 mW/m−2 have been found for SCMFCs, double chamber MFCs, and stacked MFCs with the highest being produced by the single/hybrid single-chamber type using microalgae. Hybrid MFCs may emerge as financially promising technologies worth investigating due to their low operational costs, integrating low-cost proton exchange membranes such as PVA-Nafion-borosilicate, and electrodes made of natural materials, carbon, metal, and ceramic. MFCs are mostly used in laboratories due to their low power output and the difficulties in assessing the economic feasibility of the technology. The MFCs can generate incomes of as much as $2,498.77 × 10−2/(W/m2) annually through wastewater treatment and energy generation alone. The field application of MFC technology is also narrow due to its microbiological, electrochemical, and technological limitations, exacerbated by the gap in knowledge between laboratory and commercial-scale applications. Further research into novel and economically feasible electrode and membrane materials, the improvement of electrogenicity of the microbes used, and the potential of hybrid MFCs will provide opportunities to launch MFCs from the laboratory to the commercial-scale as a bid to improve the global energy security in an eco-friendly way