In this work, the energy efficiency of the lithium-ion batteries (LIB) with graphite anode and LiFePO 4 cathode (G/LFP) at different nominal capacities and charge/discharge rates is studied through multiphysics modeling and computer simulation. After characterizing all the heat generation sources in the cell, the total heat generation in LIBs is calculated and the charge/discharge efficiency plots at different temperatures are obtained. Since G/LFP LIBs have a wide range of applications in passenger and commercial electric vehicles (EVs), the result of this study assist engineer toward more efficient battery pack design.

Substantial time and money have been directed toward photovoltaic solar power. However, mitigation of dust on solar panels has been largely neglected. The objective of this research was to determine the performance and power consumption of an electrodynamic dust shield (EDS) to clean solar panels as a function of dust particle size. We utilized a discrete element method to computationally simulate the transport, collision, and electrodynamic interactions of particles subjected to electrodynamic waves generated by an EDS. The EDS consisted of electrodes embedded within a dielectric material. 1250 monodisperse particles with diameters of 30–50 μm were simulated. In the absence of particle-particle interactions, an increase in diameter increased particle transport distance due to increased particle charge. However, inclusion of particle-particle collisions produced interactions such that an intermediate diameter yielded the smallest transport distance. Average power required to lift a particle off the surface was smallest with the smallest particle; however, power requirement decreased with diameter with a constant loading of particles on the EDS. Calculated from our simulation data, power consumption per unit area of an experimental EDS agreed with previous experimental studies. Our study elucidated important aspects of EDS operation and power consumption to mitigate dust on solar panels.

There is an enormous potential for energy generation from the mixing of sea and river water at global estuaries. If technologies are developed which are capable of converting this energy into a usable form (electricity or fuels), salinity gradient energy may be able to dramatically increase the worlds supply of renewable energy. Here we present a novel approach to convert this source of energy directly into hydrogen and electricity using Reverse Electrodialysis (RED). RED relies on converting ionic current to electric current using multiple membranes and redox based electrodes. A thermodynamic model for RED is created to evaluate the electricity and hydrogen which can be extracted from natural mixing processes. With equal volumes of HC and LC solutions (0.001m 3 ), the maximum energy extracted is found to occur with 5 number of membrane pairs. At this operating point, 0.4 kWh/m 3 can be extracted as electrical energy and 0.95 kWh/m 3 of energy is extracted as hydrogen energy. The electrical energy conversion efficiency approaches 15%, whereas the hydrogen energy efficiency is 35%. Overall, the maximum system conversion of Gibbs free energy to electrical and hydrogen energy approaches 50%. The results show that as the number of membrane pairs increases from 5 to 20, the hydrogen power density decreases from 13.2 W/m 2 to 3.7 W/m 2 . Likewise, the power density from electrical energy decreases from 1 W/m 2 to 0.3 W/m 2 . This is because of increase in the total membrane area as increasing the number of membrane pairs. The stack voltage increased from 1.5V to 6V as the number of membrane pairs is increased from 5 to 20. This corresponds to an increase in internal resistance from 600 Ω.cm 2 to 2400 Ω.cm 2 . Long term trade-off between improving the system voltage, while decreasing the system resistance will be crucial for improved long term RED performance. Furthermore, optimum operation of RED, depends on proper selection of external resistance. A small external resistance will increase hydrogen energy and decrease electrical energy, particularly using a small number of membrane pairs. With the fixed small external resistance, as increasing the number of membrane pairs, the difference between internal and external resistance increases. Therefore, the load potential and current density do not increase considerably. For the cases analyzed with 8.29 Ω.cm 2 external resistance, the maximum current density increases from 11.1 mA/cm 2 to 12.4 mA/cm 2 as the number of membrane pairs increases from 5 to 20. Likewise, the load potential rises from 92 mV to 102 mV.

Dye Sensitized Solar Cells (DSSCs) are low cost solar cells offering big room for improvements in its photovoltaic performance by maneuvering semiconductor properties, dye adsorption, electrolyte stability etc. For the first time, we have co-doped TiO 2 with silver (Ag) and copper (Cu) to enhance both charge collection and light absorption as well as reduce recombinations for DSSCs. For high solar cell efficiency 3wt% Cu and 3wt% Cu:Ag doped TiO 2 nps were successfully prepared for Dye Sensitized Solar Cells (DSSCs). Modified photoanode was prepared using surface adsorbed N719 dye on doctor blade coated TiO 2 , Cu:TiO 2 and Cu:Ag:TiO 2 thin films. It was observed that optimum doping concentration of Cu and silver was 3wt% each. DSSCs with Cu:Ag:TiO 2 thin film showed higher conversion efficiency under full sunlight illumination when compared to DSSCs assembled using Cu:TiO 2 and undoped TiO 2 . The obtained efficiencies for DSSCs with undoped TiO 2 , Cu:TiO 2 and Cu:Ag:TiO 2 photoanodes were 2%, 2.7% and 4.5% respectively. Solar cells assembled with Cu only doped TiO 2 electrode when compared with cells assembled using pristine TiO 2 , showed an increase in Voc while Jsc was decreased Furthermore, cells doped with both Ag and Cu showed enhancement in both V oc and J sc . The enhancement in cell performance has been discussed in context of morphology, crystal phase, presence of bonds etc. in nanoparticles. Considering overall better performance, Cu:Ag doped TiO 2 photoanodes can be considered as potential photoanodes in DSSCs.

In this paper, effects of a standard plasma actuator on non-premixed turbulent reacting flows in a unique gas turbine combustion chamber have been studied numerically. The computational simulation is conducted by employing the Reynolds Averaged Navier-Stokes (RANS) approach. Chemical reaction kinetics has been modeled using the eddy dissipation concept (EDC) model. The numerical simulation has been carried out by Finite Element Methods. High voltage potential between two copper electrodes separated by a dielectric material has been applied which leads to the generation of plasma and an electric field, which creates a body force. It was found that by orienting the plasma force in the desired direction, combustion rate can be accelerated or controlled. The numerical results have been presented through velocity, temperature, and species concentration profiles under different combustion conditions.

Recovering waste heat from automobiles remains an inviting subject for research. Solid-state thermoelectric generators (TEGs) have been widely investigated for this purpose, but their practical application remains challenging. An alternative to TEGs are thermogalvanic cells. Temperature difference between hot and cold electrodes creates a potential difference. Once connected to a load, electrical current and power are delivered, converting heat into electricity. In this work, we investigate the feasibility of incorporating such systems into automobiles. We carry out the experiments under real-world conditions. A climate-controlled wind tunnel is built to provide equivalent conditions to the ambient air stream under the car. The demonstrated system achieved a power density on the order of mW m −2 . We compare the power generated to those of TEGs currently tested by GM, Honda, BMW and Ford. Further, a simple economic estimation is calculated to assess the $ per Watt cost of future practical thermogalvanic waste heat recovery system.

Void fraction is one of important physical values for gas-liquid two-phase flow in nuclear power plants, and it is an essential parameter for designs and performance evaluations of devices, including a core of BWR and so on. Therefore void fraction measurement with real time, high temporal resolution and high spatial resolution has been needed. In several void fraction measurement methods, electric measurement methods of void fraction can realize real-time measurement. In previous studies, conductance methods capacitance methods, wire mesh methods and tomography techniques have been studied. In the present study, we research on a constant electric current method. This method can measure void fraction with higher temporal resolution and simpler systems. In previous study, the constant electrical current method has been applied in annular flow mainly. However, the method cannot be applied to three dimensional dispersed bubbly flow. This is because void fraction is estimated by cross-section ratio of gas and liquid phases in this method. In the present study, Maxwell’s theory and polarization method are applied to calculation method of void fraction from voltage measured by constant electrical current method, and we try to measure void fraction in dispersed bubbly flow. Maxwell’s theory is a calculation of a mixture with two materials of different conductivity. The polarization method proposed in this study assumes bubbles to be dielectric bodies and void fraction is estimated by the polarization electric field of the bubbles. In the experimental results, the void fractions in the three dimensional dispersed bubbly flow can be estimated with Maxwell’s theory and the polarization method. The void fractions estimated with these methods are more accurately than the previous method. Furthermore, it is experimentally clarified that the present proposed method can follow highly temporal void fluctuations of bubbly and froth flows. In addition, effects of intervals between electrodes and structures of electrodes are experimentally investigated.

Electrostatic precipitator (ESP) modeling development has reached the point in which internal algorithms completely simulate the operation and particulate collection physics of full-scale units. The modern ESPVI 4.0 series of models by using advanced techniques are able to evaluate changes in a precipitator’s configuration and operation to optimize its performance. The author’s applied these techniques to ESPs’ at the Kashira Power Plant near Moscow, having relatively small specific collector area’s (SCA), whose performance will have to be enhanced to meet emerging standards. Advanced modeling techniques include determining electrode and particle properties, operation below back corona onset, and effects of improved electrodes and electrical conditions. The precipitators with collection efficiencies of 88.4 (without natural gas co-firing) up to 93% (with partial co-firing) are shown to be capable of efficiencies of up to 99% by application of modest changes in configuration and operation. The advanced modeling techniques described in this paper are not only important for Kashira, they are also applicable to other power stations requiring performance optimization.

Increasingly more stringent particulate standards in India are being met by large and expensive electrostatic precipitators for new coal-fired power stations. The older and smaller units require upgrades. The Proactive Approach combining experience and knowledge with the application of a modern ESP model has been developed to help identify low-cost upgrade options. The approach was applied to a poorly operating medium sized Indian ESP not meeting the newer regulations. After defining the discharge electrode and particle size properties the precipitator was virtually restored to its proper design performance within the computer. Then a number of relatively low-cost options were identified to increase the migration velocity and decrease the gas flow. These approaches indicated that the precipitator could achieve lower emission levels that could meet the newer emission requirements. The Proactive Approach is easily and economically applicable to other precipitators in India and elsewhere.