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Abstract Temperature is one of the factors which affect the power availability, driveability and durability of the battery pack. Folded fin and serpentine channel are commonly used to provide cooling for the battery pack. During the cooling process, fluid absorbed the heat generated along the flow direction and caused the reduction of the cooling capacity. Hence, downstream temperature is always higher than the upstream temperature. Inconsistent cooling effect will lead to high variation of temperature distribution and shorten the life expectancy of the battery pack. In this study, a battery module consists of three pieces of LiFePO4 pouch cell arranged side by side, and aluminium foam is sandwiched between two heat spreaders to form a cooling plate. Aluminium foams with different porosity and pores density were modelled to investigate the thermal performance and flow field numerically. Correlation of Nusselt number, permeability and resistance loss coefficient from the literature was extracted and used in the CFD simulation. From the simulation results, it is shown that 10 PPI aluminium foam with 0.918 porosity offered the highest thermal performance and lowest flow resistance. Hence, the optimized aluminium foam cooling plate can be used as a new type of cooling system for the battery pack.

Abstract Global energy consumption is increasing at a dramatic rate and will likely continue to do so. The major source of energy is still fossil fuel, which has resulted in the well-documented problem of global warming due to the emission of greenhouse gases from the burning of such fuel. Climate change and global warming are among the crucial and complex issues encountered by the world today, and they require an immediate solution. Technological innovation is the key to ensuring energy security without causing emissions and providing efficient cost-effective energy solutions. Power electronic technologies offer high reliability and renewable energy conversion efficiency, thus contributing to energy conservation, improving energy efficiency, and helping in the mitigation of harmful global emissions. This review focuses on various aspects of power electronic technologies and their importance in tackling carbon emission and global warming problems. The key topologies of power electronic converters are explained based on types, control difficulties, benefits, and drawbacks. Power electronic controllers utilized for energy conversion are comprehensively reviewed with regard to their structure, algorithm complexity, strengths and weaknesses, and mathematical modeling. The review focuses on power converters and controllers used in different applications and highlight their contributions to energy conservation, increasing the share of renewable energy sources, and mitigating emissions. Moreover, existing research gaps, issues, and challenges are identified. The insights provided by are expected to lead to the enhanced development of advanced power electronic converters and controllers for sustainable energy conversion. Such development can reduce carbon emissions and mitigate global warming.

Abstract The study on immobilized titania (TiO2) nanoparticles semiconductor on stainless steel mesh for photocatalytic conversion of CO2 and CH4 has been investigated. Properties of commercial and calcinated photocatalysts on mesh surface were characterized using UV–vis spectra, BET, FESEM and XRD. The photoreduction products were identified with FTIR and GC. The process conditions was optimized using experimental design and process optimization tools to determine the maximum desired response via Response Surface Methodology (RSM) in conjunction with central composite rotatable design (CCRD). The experimental parameters were stainless steel mesh size, amount of titania nanoparticles, calcination temperature, UV light power and initial ratios of CO2:CH4:N2 in feed. Calcination of coated titania nanoparticles increased the absorption of UV–vis light while uniform photocatalyst structure commensurate with decreasing agglomeration. The optimal conditions for maximum CO2 conversion of 37.9% were determined as stainless steel mesh size of 140, coated titania nanoparticles on mesh of 4 g, calcination temperature of 600 °C, UV light power of 250 W and 10% of CO2 in feed. Correspondingly, the selectivity of products were 4.7%, 4.3%, 3.9%, 41.4% and 45.7% for ethane, acetic acid, formic acid, methyl acetate and methyl formate, respectively. The kinetic model, based on Langmuir–Hinshelwood, incorporated photocatalytic adsorptive reduction and oxidation reactions over the catalyst surface, and fitted-well with the experimental data.

The United Nations Climate Change Conference COP26 held in 2021 concluded a global effort to hasten the energy transition toward a net-zero emission industry. As such, green initiatives, which transition the conventional oil and gas (O&G) sector towards a circular economy (CE) are necessary. In this work, the integration of waste oil re-refining technology is proposed as a potential strategy to enhance the circularity of the O&G industry. A two-step sequential model, which incorporates multiple systematic analytical tools (e.g., multi-objective decision analysis, information entropy, geospatial information, clustering, and routing analysis) is developed to determine: (i) optimal waste oil re-refinery technologies, and (ii) optimal supply chain design, which addresses the location for setting up the process facilities and the delivery routes, with the consideration of both economic and environmental performances. The effectiveness of the proposed strategy is demonstrated through a case study in Malaysia (that covers both East and West Malaysia). The analysis showed that the proposed strategy is capable of improving economic and environmental performances by about 9.59% and 46.55%, respectively. This work is essentially a useful reference for decision-makers and policymakers in making nationwide transition planning in the O&G sector.

Abstract The concept of external fired micro gas turbine (EFMGT) using biomass fuels is getting more attention in the last two decades. However, most of the studies were conducted using computer simulation to evaluate the EFMGT systems with a lack of experimental studies. A small scale EFMGT was developed using a vehicular turbocharger as a micro gas turbine. Different micro turbine startup methods were experimentally investigated with maximum turbine inlet temperature and pressure of about 694 °C and 2.1 bar, respectively. The difficulties experienced during the turbocharger engine startup process are reported in this paper. Driving the turbocharger shaft from the compressor side using the air flow hydraulic power was not a sufficient method for the EFMGT unlike the directly fired turbine. The only proven turbine startup method for the EFMGT is the mechanically driven turbine shaft.

Lean premixed swirl stabilized combustion is one of the most successful technologies for NOx reduction in gas turbines. The creation of inherent coherent structures such as recirculation zones is one of the main advantages of these flow-stabilized systems since these zones create regions of low velocity that allow heat transfer improvement between reactants and products while increasing residence time for unburned species. However, these effects can also affect the stability of the flame under lean conditions, with various instabilities that can appear during the combustion stage such as flashback, blowoff, autoignition, etc. These processes are even more complex when new alternative fuels are being used for power generation applications. Synthesis gases (syngas) are some of the most concerning out of the available range of fuels as their heating values, flame speeds, ignition energies, etc. are highly dependent on the combination of species that comprise them. Since new gas turbines need to deal with these new blends for fuel flexibility and current lean premixed swirled stabilized systems seem to be the most cost effective-technical option to keep NOx down, gas turbine designers need more information on how to properly design their equipment to achieve stable flames with low NOx whilst avoiding instabilities. Therefore, this paper presents a study using numerical and experimental analyses to provide guidance on the use of CH4/H2/CO blends in tangential swirl burners. Methane content was decreased from 50% to 10% (volume) with the remaining amount being split equally between carbon monoxide and hydrogen. Ambient temperature conditions were assessed using a swirl number close to 1.0. Particle Image Velocity was used to experimentally validate numerical predictions and determine features of the coherent structures affecting the flame close to the nozzle. Modelling was carried out employing the k-ω SST turbulence model, providing more information about the impact of these structures and the flame turbulent nature close to blowoff limits. The study emphasizes the analysis of various nozzles with different angles and how these geometrical changes at the outlet of the swirl chamber affect the onset of blowoff. Recommendations on the use of RANS CFD modelling are provided on the basis of blend composition.

Abstract This study examines the feasibility of capturing and storing the coolth from the winter and the heat from the summer in the ground by utilizing the groundwater’s ability to phase change as a storage media. A novel system that implements a bayonet tube heat exchanger is proposed in this study due to it’s simple design and ease of installation using a single drill hole. A lab-scale experiment of a thermally controlled ground simulator was conducted to provide a proof-of-concept of the energy storage mechanism. A conjugate, multiphase heat transfer model was developed taking into account conversation of mass, momentum and energy and validated using the experimental results. The model framework is then extended to study the energy storage potential at full scale for four Canadian cities. The first set uses an averaged sinusoidal temperature profile, while the other set uses hourly temperatures from weather monitoring stations. Results of the study showed the long-term aggregated energy extraction was similar between both sets, however, over the short-term the results are more chaotic due to the nature of the weather. The system is thus best suited as a pre-heating or pre-cooling stage, making use of low-grade heat/cooling to decrease the need to use high grade energy (electricity or natural gas) over which the operator has stronger control.