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Liquid Metal Batteries (LMBs) are a promising grid-scale energy storage technology that offers low costs per kilowatt-hour, high energy and current densities, as well as low fade rates. The all-liquid composition of the batteries, as well as the presence of temperature gradients and electric and magnetic fields, result in the occurrence of multiple fluid phenomena. These can affect the hydrodynamic stability of the battery, thereby making their interactions critical to understand. In this work, the interaction of Rayleigh-Bénard convection and Electro-vortex flow is investigated as these types of flow will be present in Liquid Metal Batteries from laboratory to grid-scale. A single-layer electrode is simulated, and the computed results compared with experimental data from the literature. It was found that Rayleigh-Bénard convection is unsteady in the liquid metal electrode. The introduction of a 2 A current stabilises the convection cells, whilst the introduction of a 40 A current leads to the dominance of Electro-vortex flow at the central region of the electrode. The results in this work match experimental data closer than previously published models offering insight into the interaction between Rayleigh-Bénard convection and Electro-vortex flow in the anodes of discharging Liquid Metal Batteries.
Declan Finn Keogh; Victoria Timchenko; John Reizes; Chris Menictas. Modelling Rayleigh-Bénard convection coupled with electro-vortex flow in liquid metal batteries. Journal of Power Sources 2021, 501, 229988 .
AMA StyleDeclan Finn Keogh, Victoria Timchenko, John Reizes, Chris Menictas. Modelling Rayleigh-Bénard convection coupled with electro-vortex flow in liquid metal batteries. Journal of Power Sources. 2021; 501 ():229988.
Chicago/Turabian StyleDeclan Finn Keogh; Victoria Timchenko; John Reizes; Chris Menictas. 2021. "Modelling Rayleigh-Bénard convection coupled with electro-vortex flow in liquid metal batteries." Journal of Power Sources 501, no. : 229988.
After 35 years of research and development that began at UNSW Sydney in 1985, the All-Vanadium Redox Flow Battery is now being commercialized by a number of companies around the world in applications such as load levelling, peak shaving and renewable energy storage. It is unique amongst all flow battery chemistries in that it uses the same element in both half-cells, thereby eliminating problems of cross contamination and providing indefinite life for the electrolyte. This article presents a detailed overview of the VRFB technology, beginning with the original research and development at UNSW, through to the more recent improvements in cell materials and design that have enhanced power density and reduced costs. Early field testing and current commercialization activities are also described.
Maria Skyllas-Kazacos; Chris Menictas. Vanadium Redox Flow Batteries. Reference Module in Earth Systems and Environmental Sciences 2021, 1 .
AMA StyleMaria Skyllas-Kazacos, Chris Menictas. Vanadium Redox Flow Batteries. Reference Module in Earth Systems and Environmental Sciences. 2021; ():1.
Chicago/Turabian StyleMaria Skyllas-Kazacos; Chris Menictas. 2021. "Vanadium Redox Flow Batteries." Reference Module in Earth Systems and Environmental Sciences , no. : 1.
This study generates novel manifold microchannel heat sink structures for high heat flux cooling, by applying topology optimisation within a multi-objective 3D conjugate heat transfer model. Compared to rectangular manifold microchannels, the proposed structures reduce pressure drop by 17 % (7.2 kPa - 6.0 kPa) by suppressing stagnation regions, and a more substantial 79.2 % (5.8 kPa - 1.2 kPa) by also limiting nozzle constrictions. This structure simultaneously reduces thermal resistance by 22.4 % (0.148 W/cm2K – 0.115 W/cm2K) by introducing intricate pins and constrictions, which augment jet impingement and counteract streamwise heating of the fluid. This study reveals some topology optimisation deficiencies: manual tuning of conditions, penetration of fluid to solid, and discrete geometry extraction. However, the resulting structures demonstrate how the topology optimisation process may leverage advances in additive manufacturing to extend the capabilities of high heat flux coolers.
Nicholas Gilmore; Victoria Timchenko; Chris Menictas. Manifold microchannel heat sink topology optimisation. International Journal of Heat and Mass Transfer 2021, 170, 121025 .
AMA StyleNicholas Gilmore, Victoria Timchenko, Chris Menictas. Manifold microchannel heat sink topology optimisation. International Journal of Heat and Mass Transfer. 2021; 170 ():121025.
Chicago/Turabian StyleNicholas Gilmore; Victoria Timchenko; Chris Menictas. 2021. "Manifold microchannel heat sink topology optimisation." International Journal of Heat and Mass Transfer 170, no. : 121025.
The rapid development of metal 3D printing techniques has enabled the exploration of complex free-convection heat sink designs. Small free-convection heat sinks with pin-fin arrays (or novel geometries) are widely employed at different orientations in a variety of electronic devices, yet there is limited understanding of how orientation impacts their heat transfer behavior. This article characterizes the orientation-dependent performance of a small, tapered pin, free-convection heat sink (named HS17) manufactured with direct metal laser sintering for use with a thermoelectric scalp cryotherapy device for the prevention of chemotherapy-induced alopecia. A validated numerical model and custom-built free-convection test rig were used to investigate the heat sink’s performance over the orientation range of 0 deg to 135 deg. HS17 maintained relatively robust performance over the 0 deg to 90 deg range; however, the thermal resistance (Rth) at 112.5 deg and 135 deg was 6% and 11% higher compared to the 90 deg case, respectively. The heat sink design was modified to include a 22.5 deg wedge base (named HS17-W) to mitigate this performance decline, which is important to ensure safe and continued operation of the cryotherapy device. Compared to the flat base heat sink, the wedge-base design successfully reduced Rth from 11.9 K/W, 12.5 K/W, and 12.8 K/W to 11.5 K/W, 11.8 K/W, and 12.3 K/W at 90 deg, 112.5 deg, and 135 deg, respectively. These results demonstrate the effectiveness of the current proposed design to improve the performance of free-convection heat sinks at downward-facing orientations.
Mark Baldry; Victoria Timchenko; Chris Menictas. The Effect of Orientation on the Performance of Small Free-Convection Heat Sinks for Use With a Thermoelectric Cryotherapy Device. Journal of Thermal Science and Engineering Applications 2020, 13, 1 -23.
AMA StyleMark Baldry, Victoria Timchenko, Chris Menictas. The Effect of Orientation on the Performance of Small Free-Convection Heat Sinks for Use With a Thermoelectric Cryotherapy Device. Journal of Thermal Science and Engineering Applications. 2020; 13 (4):1-23.
Chicago/Turabian StyleMark Baldry; Victoria Timchenko; Chris Menictas. 2020. "The Effect of Orientation on the Performance of Small Free-Convection Heat Sinks for Use With a Thermoelectric Cryotherapy Device." Journal of Thermal Science and Engineering Applications 13, no. 4: 1-23.
The current study proposes compact and adaptable manifold configurations for achieving uniform flow distribution with minimal pressure drop, for electronics cooling and many other industrial applications. Two-dimensional topology optimisation generates new manifold configurations, referred to as mini-baffle and baffle. Both configurations use proportionately sized obstructions to regulate flow distribution and achieve excellent uniformity. Elliptical pins, with parametrically optimised diameters, are adopted to represent the mini-baffle configuration and tested using a three-dimensional model and flow visualisation experiments. Computational results show that introducing these pins reduces the variation of normalised channel flow rates from 19% to 1% with only an 8% increase in the pressure drop, at a Reynolds number of 200. Experimental results support this, with variation reduced from 20% to 7%, the slight increase due to manufacturing limitations. Results also show the influence of vortices, formed at the inlet, on flow distribution. A test section printed in a single piece demonstrates a streamlined and cost-effective manufacturing method for milli-fluidic devices. Coupling topology with parameter optimisation provides a method for accurately extracting discrete optimised geometries for physical manufacturing.
Nicholas Gilmore; Amin Hassanzadeh-Barforoushi; Victoria Timchenko; Chris Menictas. Manifold configurations for uniform flow via topology optimisation and flow visualisation. Applied Thermal Engineering 2020, 183, 116227 .
AMA StyleNicholas Gilmore, Amin Hassanzadeh-Barforoushi, Victoria Timchenko, Chris Menictas. Manifold configurations for uniform flow via topology optimisation and flow visualisation. Applied Thermal Engineering. 2020; 183 ():116227.
Chicago/Turabian StyleNicholas Gilmore; Amin Hassanzadeh-Barforoushi; Victoria Timchenko; Chris Menictas. 2020. "Manifold configurations for uniform flow via topology optimisation and flow visualisation." Applied Thermal Engineering 183, no. : 116227.
Human health is a key pillar of modern conceptions of sustainability. Humanity pays a considerable price for its dependence on fossil-fueled energy systems, which must be addressed for sustainable urban development. Public hospitals are focal points for communities and have an opportunity to lead the transition to renewable energy. We have reimagined the healthcare energy ecosystem with sustainable technologies to transform hospitals into networked clean energy hubs. In this concept design, hydrogen is used to couple energy with other on-site medical resource demands, and vanadium flow battery technology is used to engage the public with energy systems. This multi-generation system would reduce harmful emissions while providing reliable services, tackling the linked issues of human and environmental health.
Nicholas Gurieff; Donna Green; Ilpo Koskinen; Mathew Lipson; Mark Baldry; Andrew Maddocks; Chris Menictas; Jens Noack; Behdad Moghtaderi; Elham Doroodchi. Healthy Power: Reimagining Hospitals as Sustainable Energy Hubs. Sustainability 2020, 12, 8554 .
AMA StyleNicholas Gurieff, Donna Green, Ilpo Koskinen, Mathew Lipson, Mark Baldry, Andrew Maddocks, Chris Menictas, Jens Noack, Behdad Moghtaderi, Elham Doroodchi. Healthy Power: Reimagining Hospitals as Sustainable Energy Hubs. Sustainability. 2020; 12 (20):8554.
Chicago/Turabian StyleNicholas Gurieff; Donna Green; Ilpo Koskinen; Mathew Lipson; Mark Baldry; Andrew Maddocks; Chris Menictas; Jens Noack; Behdad Moghtaderi; Elham Doroodchi. 2020. "Healthy Power: Reimagining Hospitals as Sustainable Energy Hubs." Sustainability 12, no. 20: 8554.
To meet the intensifying demands of electronics cooling the current study proposes an open manifold microchannel heat sink, which substantially reduces the pressure drop of a conventional manifold microchannel heat sink while retaining a low thermal resistance, thin profile (< 2 mm) and planar geometry suited to microfabrication. The open heat sink achieves this by eliminating ineffective nozzle constrictions, specifically by removing channel walls beneath the slot nozzle. Two three-dimensional conjugate heat transfer models are used, including a single microchannel or a single manifold channel pair with hundreds of interconnecting microchannels. The performance of the open geometry is compared to an unmodified baseline geometry. In the microchannel model, the open case showed ideal pressure drop reductions of 45 % to 75 % with a negligible change to thermal resistance, at flow rates between 0.2 L/min and 1.0 L/min. Chamfering the tips of the microchannel walls show similar trends, although to a lesser degree. In the manifold model, the open case showed pressure drop reductions of 25 %, with thermal resistance slightly decreasing at flow rates below 0.58 L/min (-4 % to 1 %) and increasing at flow rates above 0.70 L/min (11 % to 21 %). These changes in thermal resistance were attributed to flow maldistribution, which may be alleviated through optimisation of the manifold convergence profile. At a flow rate of 1.32 L/min, the open geometry achieved a thermal resistance of 0.120 cm2K/W with a pressure drop of 10.3 kPa.
Nicholas Gilmore; Victoria Timchenko; Chris Menictas. Open manifold microchannel heat sink for high heat flux electronic cooling with a reduced pressure drop. International Journal of Heat and Mass Transfer 2020, 163, 120395 .
AMA StyleNicholas Gilmore, Victoria Timchenko, Chris Menictas. Open manifold microchannel heat sink for high heat flux electronic cooling with a reduced pressure drop. International Journal of Heat and Mass Transfer. 2020; 163 ():120395.
Chicago/Turabian StyleNicholas Gilmore; Victoria Timchenko; Chris Menictas. 2020. "Open manifold microchannel heat sink for high heat flux electronic cooling with a reduced pressure drop." International Journal of Heat and Mass Transfer 163, no. : 120395.
The world is moving to the next phase of the energy transition with high penetrations of renewable energy. Flexible and scalable redox flow battery (RFB) technology is expected to play an important role in ensuring electricity network security and reliability. Innovations continue to enhance their value by reducing parasitic losses and maximizing available energy over broader operating conditions. Simulations of vanadium redox flow battery (VRB/VRFB) cells were conducted using a validated COMSOL Multiphysics model. Cell designs are developed to reduce losses from pump energy while improving the delivery of active species where required. The combination of wedge-shaped cells with static mixers is found to improve performance by reducing differential pressure and concentration overpotential. Higher electrode compression at the outlet optimises material properties through the cell, while the mixer mitigates concentration gradients across the cell. Simulations show a 12% lower pressure drop across the cell and a 2% lower charge voltage for improved energy efficiency. Wedge-shaped cells are shown to offer extended capacity during cycling. The prototype mixers are fabricated using additive manufacturing for further studies. Toroidal battery designs incorporating these innovations at the kW scale are developed through inter-disciplinary collaboration and rendered using computer aided design (CAD).
Nicholas Gurieff; Declan Finn Keogh; Mark Baldry; Victoria Timchenko; Donna Green; Ilpo Koskinen; Chris Menictas. Mass Transport Optimization for Redox Flow Battery Design. Applied Sciences 2020, 10, 2801 .
AMA StyleNicholas Gurieff, Declan Finn Keogh, Mark Baldry, Victoria Timchenko, Donna Green, Ilpo Koskinen, Chris Menictas. Mass Transport Optimization for Redox Flow Battery Design. Applied Sciences. 2020; 10 (8):2801.
Chicago/Turabian StyleNicholas Gurieff; Declan Finn Keogh; Mark Baldry; Victoria Timchenko; Donna Green; Ilpo Koskinen; Chris Menictas. 2020. "Mass Transport Optimization for Redox Flow Battery Design." Applied Sciences 10, no. 8: 2801.
The world is moving to the next phase of the energy transition with high penetrations of renewable energy. Flexible and scalable redox flow battery (RFB) technology is expected to play an important role in ensuring electricity network security and reliability. Continuous performance improvements will further enhance their value by reducing parasitic losses and maximizing available energy conversion over broader operating conditions. Concentration overpotentials from poor internal reactant distribution at high and low states of charge (SOC) limit power densities and are thus an important area of investigation. However, efforts to address these coupled electrochemical phenomena can compromise mechanical performance. Modelling and simulation of cell design innovations have shown it is possible to reduce losses from pump energy while increasing the availability of active species where required. The combination of wedge-shaped cells with static mixers investigated in this paper can reduce pressure drop and improve energy efficiency. Toroidal vanadium redox flow battery (VRB/VRFB) designs incorporating this innovation are presented for further development to improve community engagement with the technology.
Nicholas Gurieff; Declan Finn Keogh; Mark Bladry; Victoria Timchenko; Donna Green; Ilpo Koskinen; Chris Menictas. Mass Transport Optimization for Redox Flow Battery Design. 2020, 1 .
AMA StyleNicholas Gurieff, Declan Finn Keogh, Mark Bladry, Victoria Timchenko, Donna Green, Ilpo Koskinen, Chris Menictas. Mass Transport Optimization for Redox Flow Battery Design. . 2020; ():1.
Chicago/Turabian StyleNicholas Gurieff; Declan Finn Keogh; Mark Bladry; Victoria Timchenko; Donna Green; Ilpo Koskinen; Chris Menictas. 2020. "Mass Transport Optimization for Redox Flow Battery Design." , no. : 1.
Redox flow batteries (RFBs), provide a safe and cost-effective means of storing energy at grid-scale, and will play an important role in the decarbonization of global electricity networks. Several approaches have been explored to improve their efficiency and power density, and recently, cell geometry modification has shown promise in efforts to address mass transport limitations which affect electrochemical and overall system performance. Flow-by electrode configurations have demonstrated significant power density improvements in laboratory testing, however, flow-through designs with conductive felt remain the standard at commercial scale. Concentration gradients exist within these cells, limiting their performance. A new concept of redistributing reactants within the flow frame is introduced in this paper. This research shows a 60% improvement in minimum V3+ concentration within simulated vanadium redox flow battery (VRB/VRFB) cells through the application of static mixers. The enhanced reactant distribution showed a cell voltage improvement by reducing concentration overpotential, suggesting a pathway forward to increase limiting current density and cycle efficiencies in RFBs.
Nicholas Gurieff; Declan Finn Keogh; Victoria Timchenko; Chris Menictas. Enhanced Reactant Distribution in Redox Flow Cells. Molecules 2019, 24, 3877 .
AMA StyleNicholas Gurieff, Declan Finn Keogh, Victoria Timchenko, Chris Menictas. Enhanced Reactant Distribution in Redox Flow Cells. Molecules. 2019; 24 (21):3877.
Chicago/Turabian StyleNicholas Gurieff; Declan Finn Keogh; Victoria Timchenko; Chris Menictas. 2019. "Enhanced Reactant Distribution in Redox Flow Cells." Molecules 24, no. 21: 3877.
Magnetorheological (MR) fluid is a smart material fabricated by mixing magnetic-responsive particles with non-magnetic-responsive carrier fluids. MR fluid dampers are able to provide rapid and reversible changes to their damping coefficient. To optimize the efficiency and effectiveness of such devices, a computational model is developed and presented where the flow field is simulated using the computational fluid dynamics approach, coupled with the magnetohydrodynamics model. Three different inlet pressure profiles were designed to replicate real loading conditions are examined, namely a constant pressure, a sinusoidal pressure profile, and a pressure profile mimicking the 1994 Northbridge earthquake. When the MR fluid damper was in its off-state, a linear pressure drop between the inlet and the outlet was observed. When a uniform perpendicular external magnetic field was applied to the annular orifice of the MR damper, a significantly larger pressure drop was observed across the annular orifice for all three inlet pressure profiles. It was shown that the fluid velocity within the magnetized annular orifice decreased proportionally with respect to the strength of the applied magnetic field until saturation was reached. Therefore, it was clearly demonstrated that the present model was capable of accurately capturing the damping characteristics of MR fluid dampers.
Darson Dezheng Li; Declan Finn Keogh; Kevin Huang; Qing Nian Chan; Anthony Chun Yin Yuen; Chris Menictas; Victoria Timchenko; Guan Heng Yeoh. Modeling the Response of Magnetorheological Fluid Dampers under Seismic Conditions. Applied Sciences 2019, 9, 4189 .
AMA StyleDarson Dezheng Li, Declan Finn Keogh, Kevin Huang, Qing Nian Chan, Anthony Chun Yin Yuen, Chris Menictas, Victoria Timchenko, Guan Heng Yeoh. Modeling the Response of Magnetorheological Fluid Dampers under Seismic Conditions. Applied Sciences. 2019; 9 (19):4189.
Chicago/Turabian StyleDarson Dezheng Li; Declan Finn Keogh; Kevin Huang; Qing Nian Chan; Anthony Chun Yin Yuen; Chris Menictas; Victoria Timchenko; Guan Heng Yeoh. 2019. "Modeling the Response of Magnetorheological Fluid Dampers under Seismic Conditions." Applied Sciences 9, no. 19: 4189.
Metal additive manufacturing technologies are increasingly being adopted for rapid prototyping and to build geometrically complex designs for thermal management. This paper develops and experimentally validates a numerical model to design a high performance, small-scale heat sink for use with a thermoelectric cooling cap. The design was constrained by a heat load of 2.15 W, and a target average base temperature of 45°C as a compromise between avoiding burn injury and reducing heat dissipation requirements. Over successive numerical iterations, an optimal natural convection heat sink was developed with an estimated thermal resistance of 10.9 K.W-1 and base temperature of 44.4°C. This design featured an internal cavity in a tapered pin array, and was able to achieve a steady state base temperature that was 11.7°C cooler than a conventional design, with 51% less surface area and significantly less material.
Mark Baldry; Victoria Timchenko; Chris Menictas. Optimal design of a natural convection heat sink for small thermoelectric cooling modules. Applied Thermal Engineering 2019, 160, 114062 .
AMA StyleMark Baldry, Victoria Timchenko, Chris Menictas. Optimal design of a natural convection heat sink for small thermoelectric cooling modules. Applied Thermal Engineering. 2019; 160 ():114062.
Chicago/Turabian StyleMark Baldry; Victoria Timchenko; Chris Menictas. 2019. "Optimal design of a natural convection heat sink for small thermoelectric cooling modules." Applied Thermal Engineering 160, no. : 114062.
This paper presents a mixed receding horizon control (RHC) strategy for the optimal scheduling of a battery energy storage system (BESS) in a hybrid PV and wind power plant while satisfying multiple operational constraints. The overall optimisation problem was reformulated as a mixed-integer linear programming (MILP) problem, aimed at minimising the total operating cost of the entire system. The cost function of this MILP is composed of the profits of selling electricity, the cost of purchasing ancillary services for undersupply and oversupply, and the operation and maintenance cost of each component. To investigate the impacts of day-ahead and hour-ahead forecasting for battery optimisation, four forecasting methods, including persistence, Elman neural network, wavelet neural network and autoregressive integrated moving average (ARIMA), were applied for both day-ahead and hour-ahead forecasting. Numerical simulations demonstrated the significant increased efficiency of the proposed mixed RHC strategy, which improved the total operation profit by almost 29% in one year, in contrast to the day-ahead RHC strategy. Moreover, the simulation results also verified the significance of using more accurate forecasting techniques, where ARIMA can reduce the total operation cost by almost 5% during the whole year operation when compared to the persistence method as the benchmark.
Yuqing Yang; Stephen Bremner; Chris Menictas; Merlinde Kay. A Mixed Receding Horizon Control Strategy for Battery Energy Storage System Scheduling in a Hybrid PV and Wind Power Plant with Different Forecast Techniques. Energies 2019, 12, 2326 .
AMA StyleYuqing Yang, Stephen Bremner, Chris Menictas, Merlinde Kay. A Mixed Receding Horizon Control Strategy for Battery Energy Storage System Scheduling in a Hybrid PV and Wind Power Plant with Different Forecast Techniques. Energies. 2019; 12 (12):2326.
Chicago/Turabian StyleYuqing Yang; Stephen Bremner; Chris Menictas; Merlinde Kay. 2019. "A Mixed Receding Horizon Control Strategy for Battery Energy Storage System Scheduling in a Hybrid PV and Wind Power Plant with Different Forecast Techniques." Energies 12, no. 12: 2326.
A vanadium oxygen fuel cell is a modified form of a conventional vanadium redox flow battery (VRFB) where the positive electrolyte (VO2+/VO2+ couple) is replaced by the oxygen reduction (ORR) process. This potentially allows for a significant improvement in energy density and has the added benefit of overcoming the solubility limits of V (V) at elevated temperatures, while also allowing the vanadium negative electrolyte concentration to increase above 3 M. In this paper, a vanadium oxygen fuel cell with vanadium electrolytes with a concentration of up to 3.6 M is reported with preliminary results presented for different electrodes over a range of current densities. Using precipitation inhibitors, the concentration of vanadium can be increased considerably above the commonly used 2 M limit, leading to improved energy density.
Mandar Risbud; Chris Menictas; Maria Skyllas-Kazacos; Jens Noack. Vanadium Oxygen Fuel Cell Utilising High Concentration Electrolyte. Batteries 2019, 5, 24 .
AMA StyleMandar Risbud, Chris Menictas, Maria Skyllas-Kazacos, Jens Noack. Vanadium Oxygen Fuel Cell Utilising High Concentration Electrolyte. Batteries. 2019; 5 (1):24.
Chicago/Turabian StyleMandar Risbud; Chris Menictas; Maria Skyllas-Kazacos; Jens Noack. 2019. "Vanadium Oxygen Fuel Cell Utilising High Concentration Electrolyte." Batteries 5, no. 1: 24.
Vanadium redox flow batteries (VRFBs) offer great promise as a safe, cost effective means of storing electrical energy on a large scale and will certainly have a part to play in the global transition to renewable energy. To unlock the full potential of VRFB systems, however, it is necessary to improve their power density. Unconventional stack design shows encouraging possibilities as a means to that end. Presented here is the novel concept of variable porous electrode compression, which simulations have shown to deliver a one third increase in minimum limiting current density together with a lower pressure drop when compared to standard uniform compression cell designs.
Nicholas Gurieff; Victoria Timchenko; Chris Menictas. Variable Porous Electrode Compression for Redox Flow Battery Systems. Batteries 2018, 4, 53 .
AMA StyleNicholas Gurieff, Victoria Timchenko, Chris Menictas. Variable Porous Electrode Compression for Redox Flow Battery Systems. Batteries. 2018; 4 (4):53.
Chicago/Turabian StyleNicholas Gurieff; Victoria Timchenko; Chris Menictas. 2018. "Variable Porous Electrode Compression for Redox Flow Battery Systems." Batteries 4, no. 4: 53.
Through targeted and reproducible electrochemical treatment of glassy carbon electrodes, investigations have been carried out on the electrochemical behaviour of the oxidation of V2+, VO2+ and the reductions of VO2+, VO2+ and V3+ in order to pretreat electrodes specifically for use in vanadium redox flow batteries and, if possible, to treat them in situ. For this purpose, a glassy carbon electrode was treated potentiostatically for a period of 30 s at different potentials in the range of 500 mV–2000 mV vs. Hg/Hg2SO4 in 2 M H2SO4 and then linear sweep voltammograms were performed in the different vanadium-containing solutions. With this method, it could be shown that all reactions are extremely surface sensitive and the reaction speeds changed by several decades. The reaction rates increased significantly in all reactions compared to polished electrodes and had an optimum treatment potential of approx. 1600 mV vs. Hg/Hg2SO4, although the oxidation reaction of V2+ and the reduction reactions of V3+ and VO2+ had opposite tendencies to oxidation of VO2+ and the reduction of VO2+ in the area of low treatment potentials. In the former, the kinetics increased and in the latter, they decreased. In addition, causes were investigated using confocal microscopy and XPS. No correlation was found to the roughness or size of the stretched surfaces, although these changed significantly as a result of the treatment. XPS measurements gave indications of a dependence on hydroxyl groups for the oxidation of VO2+ and the reduction of VO2+, while for the reactions of oxygen-free cations and the reduction of VO2+ weak indications of a dependence on carboxyl groups were obtained.
Jens Noack; Nataliya Roznyatovskaya; Jessica Kunzendorf; Maria Skyllas-Kazacos; Chris Menictas; Jens Tübke. The influence of electrochemical treatment on electrode reactions for vanadium redox-flow batteries. Journal of Energy Chemistry 2018, 27, 1341 -1352.
AMA StyleJens Noack, Nataliya Roznyatovskaya, Jessica Kunzendorf, Maria Skyllas-Kazacos, Chris Menictas, Jens Tübke. The influence of electrochemical treatment on electrode reactions for vanadium redox-flow batteries. Journal of Energy Chemistry. 2018; 27 (5):1341-1352.
Chicago/Turabian StyleJens Noack; Nataliya Roznyatovskaya; Jessica Kunzendorf; Maria Skyllas-Kazacos; Chris Menictas; Jens Tübke. 2018. "The influence of electrochemical treatment on electrode reactions for vanadium redox-flow batteries." Journal of Energy Chemistry 27, no. 5: 1341-1352.
Liuyue Cao; Maria Skyllas-Kazacos; Chris Menictas; Jens Noack. A review of electrolyte additives and impurities in vanadium redox flow batteries. Journal of Energy Chemistry 2018, 27, 1269 -1291.
AMA StyleLiuyue Cao, Maria Skyllas-Kazacos, Chris Menictas, Jens Noack. A review of electrolyte additives and impurities in vanadium redox flow batteries. Journal of Energy Chemistry. 2018; 27 (5):1269-1291.
Chicago/Turabian StyleLiuyue Cao; Maria Skyllas-Kazacos; Chris Menictas; Jens Noack. 2018. "A review of electrolyte additives and impurities in vanadium redox flow batteries." Journal of Energy Chemistry 27, no. 5: 1269-1291.
This study presents a novel, thermoelectric cryotherapy cap that aims to provide effective and controlled scalp cooling to prevent hair loss for chemotherapy patients. The cap's design consists of multiple thermoelectric coolers (TECs) evenly spaced and bonded to a soft thermal interface material, tightly fitted to a patient's head. A numerical model is developed to assess the performance of alternative cap designs in relation to their ability to achieve hair follicle hypothermia. Under ideal conditions, 26.5 W of heat removal from the scalp is required to achieve the clinically-significant follicle temperature target of 22 °C. Temperature maps of the subcutaneous tissue are generated to visualise the development of hypothermic follicles, and thereby assess the effectiveness of the cap design. Transient studies show that cooling to the therapeutic temperature can be achieved within 40 minutes. To avoid the possibility of cold-induced tissue damage, individual thermoelectric cooling modules should not be operated at a cooling flux beyond approximately 3,175 W/m2. This may be achieved with 38 modules evenly spaced in a checkerboard arrangement, each providing 0.7 W of cooling to the scalp.
Mark Baldry; Victoria Timchenko; Chris Menictas. Thermal modelling of controlled scalp hypothermia using a thermoelectric cooling cap. Journal of Thermal Biology 2018, 76, 8 -20.
AMA StyleMark Baldry, Victoria Timchenko, Chris Menictas. Thermal modelling of controlled scalp hypothermia using a thermoelectric cooling cap. Journal of Thermal Biology. 2018; 76 ():8-20.
Chicago/Turabian StyleMark Baldry; Victoria Timchenko; Chris Menictas. 2018. "Thermal modelling of controlled scalp hypothermia using a thermoelectric cooling cap." Journal of Thermal Biology 76, no. : 8-20.
The intensifying heat flux demands of concentrator photovoltaics requires innovation beyond conventional passive air cooling. Passive cooling is cost effective, reliable and does not consume power. Flat lens arrangements should allow large passive heat sinks to cool at solar concentrations of up to 2000 suns to 4000 suns (1 sun = 1000 W/m2). However, as solar concentrations increase so will the necessity of active cooling. The competitiveness of active cooling is enhanced by the capacity to harvest otherwise wasted thermal energy. Pairing with phase change materials presents an opportunity to stabilise the intermittent generation of solar thermal energy. Active microchannel cooling is a strong candidate for meeting the escalating heat flux demands of concentrator photovoltaics. For meeting short term-heat flux demands, established single phase microchannel cooling is most practical. Manifold microchannels yield superior performance to single layered microchannels, although they are more difficult to manufacture. For meeting long term heat flux demands, integration of boiling flows is promising. Jet impingement onto porous microstructures demonstrates effective mitigation of flow instabilities. Future studies should apply microchannel cooling directly to concentrator photovoltaics, particularly two-phase systems. They should also test microchannel cooling over larger heater areas and consider manufacturability of heat sinks. Novel directions should also be explored, such as alteration of typically rectangular and straight manifold microchannels or use of micro-valves to suppress boiling instabilities. Incipient cooling methods, including vortex shedding, ionic jet impingement, slug flow and shear driven gas flow, may also warrant further investigations.
Nicholas Gilmore; Victoria Timchenko; Chris Menictas. Microchannel cooling of concentrator photovoltaics: A review. Renewable and Sustainable Energy Reviews 2018, 90, 1041 -1059.
AMA StyleNicholas Gilmore, Victoria Timchenko, Chris Menictas. Microchannel cooling of concentrator photovoltaics: A review. Renewable and Sustainable Energy Reviews. 2018; 90 ():1041-1059.
Chicago/Turabian StyleNicholas Gilmore; Victoria Timchenko; Chris Menictas. 2018. "Microchannel cooling of concentrator photovoltaics: A review." Renewable and Sustainable Energy Reviews 90, no. : 1041-1059.
Cheuk-Yi Cheung; Chris Menictas; Jie Bao; Maria Skyllas-Kazacos; Barry J. Welch. Spatial thermal condition in aluminum reduction cells under influences of electrolyte flow. Chemical Engineering Research and Design 2015, 100, 1 -14.
AMA StyleCheuk-Yi Cheung, Chris Menictas, Jie Bao, Maria Skyllas-Kazacos, Barry J. Welch. Spatial thermal condition in aluminum reduction cells under influences of electrolyte flow. Chemical Engineering Research and Design. 2015; 100 ():1-14.
Chicago/Turabian StyleCheuk-Yi Cheung; Chris Menictas; Jie Bao; Maria Skyllas-Kazacos; Barry J. Welch. 2015. "Spatial thermal condition in aluminum reduction cells under influences of electrolyte flow." Chemical Engineering Research and Design 100, no. : 1-14.