farshad torabi

To prevent safety issues such as thermal runaway, lithium-ion batteries must be constantly monitored. Most thermal management methods are based on designing suitable cooling systems. Also, since the surface temperature is measurable through a sensor, it is considered the main criterion of thermal management. However, in extremely fast charge-discharge operations, the core temperature can be significantly higher than the surface temperature, so the cooling system may not be able to solely maintain the core temperature in the safe range. The objective of this paper is to combine electrical and thermal management and set the core temperature as the main criterion. To achieve that, model predictive control (MPC) is implemented to control the supplied or drawn current of the battery cell and Sigma point Kalman filter (SPKF) is used to estimate model states. The simulation and experimental results indicate that incorporating MPC and nonlinear Kalman filter Estimators can be a novel strategy to simultaneously manage electrical and thermal states. It is also expected that controlling the core temperature in fast charge-discharge operations, may increase the safety and lifetime of the cell.

Electrochemical impedance spectroscopy is a powerful tool for determining the behavior of electrochemical systems. Despite being costly and time-consuming, the time-domain impedance calculation of electrochemical systems is advantageous. However, this method exhibits a high error rate under noise conditions. In this study, the linear technique is developed to minimize noise effects when calculating the impedance of electrochemical systems in the time domain. Multiple equivalent circuit samples are simulated, and the linear technique versus the standard fast Fourier transform method for a noisy input is compared. The results indicate that its error rate is considerably less than that of the fast Fourier transform. The error rate in the Li-ion battery equivalent circuit was reduced from 273.5446 using the fast Fourier transform to 0.0049 using the linear method. Notably, this reduction is significant and on the order of . Additionally, the decline in the real and imaginary parts of mean relative error is in the order of 10. It is concluded that the linear method results in less error in the presence of noise and is faster than traditional electrochemical impedance spectroscopy in the frequency domain. Thus, the linear method outperforms the fast Fourier transform method in time-domain electrochemical impedance spectroscopy.

The delayed Coker process as an upgrading process has the main impact on the productivity of the Refinery Complexes. To determine the impact of different operating conditions on the product yield distribution of the delayed coking process, several experiments were designed and conducted in a prefabricated pilot plant. The experiments were conducted on different Iranian vacuum residues at temperatures ranging from 420°C to 480°C and at atmospheric pressure. Reaction times were within the range of 5-120 minutes. A four lumps kinetic model has been developed based on the experimental results. The lumps—which included Volatile products, coke, feed, and an intermediate phase between coke and feed—were defined to precisely monitor the yield distribution of products throughout the reaction time. The feedstocks utilized were three different vacuum residues and their blends. The mixtures were produced by using different mixing ratios of the three vacuum residues. The Statistical analysis shows that this model has R-squared, RMSE, SSE, and MRE equal to 0.99, 0.022, 0.08, and 3.537%, respectively. This shows that the developed model is sufficiently accurate. The experimental and modeling results in this research reveal that by increasing the temperature, the yield of coke and gas is abated. However, the yield of the distillate is escalated. This investigation illustrates that the production of an intermediate reaction has the highest amount of activation energy in comparison with the other reactions. Also, the results indicate that the production reaction rate of coke has the highest amount compared to other reactions.

The geometry of a collector is one of the important factors that can increase the incident radiation on the collector surface. In the present study, the incident radiation for a stationary collector with cone geometry, i.e. a conical collector, is theoretically and experimentally investigated. This type of collector is always stable and does not need a fixture to install. Moreover, it has a symmetric geometry, with all its sides facing the sun. The main advantage of this collector is its ability to receive beam, diffuse, and ground-reflected radiation throughout the day. The variation of the incident radiation is theoretically estimated by using an isotropic sky model based on the available data. The theoretical data are validated by an experimental test of a conical collector of a specific size. The results show that the conical solar collector is more operative in receiving total solar radiations than a horizontal plate such as a flat-plate collector and can be a suitable option for solar water heating. A calculation of the incident radiation shows that the incident radiation is maximized when the cone angle of the conical collector is equal to the latitude of the site test.

In this paper, one-dimensional numerical optimization of lead-acid battery with finite-volume method is performed using the governing equations of battery dynamics. For validation, the present results are compared with previous studies which show good agreement. The demand for batteries with high energy and power has increased due to their use in hybrid vehicles.The major shortcoming of lead-acid batteries in industry is low energy and high weight; therefore, a cell with higher energy and lower thickness is designed by using particle swarm optimization based on developed simulation code which is less time consuming and much faster than experimental method. The results of optimization show that an optimal battery that has 85 percent higher energy can be made with the same cell length. The results also show that an optimum cell battery can be obtained with a decrease of 25 percent in weight and 23 percent in dimensions while keeping the energy content constant.

Peltier technology opens new opportunities for special applications. In the current project, this technology was applied to design and fabricate a portable thermoelectric beverage cooler and thermoelectric cup. The simulation and results of the experiment showed that the common beverage cooler is not a suitable design for ignoring the effect of natural convection in cooling. In our thermoelectric cup, the drawbacks of previous design were eliminated. The advantages of the present design over the former design are the heat sink's temperature reduction from 60°C to about 31°C, and the cooling process enhancement, such that the water was cooled down to about 7°C.

The shape of wake behind a wind turbine is normally assumed to have a hat shape for the models used in wind farm layout optimization purposes; however, it is know from experimental tests and numerical simulations that this is not a real assumption. In reality, the results of actual measurements and detailed numerical simulation show that the velocity in wake region has a S-shape profile. The present study calculated a semi-analytical profile for the shape of the wake behind a wind turbine using blade element momentum method. It is shown that the wake shape differs in different operational conditions and geometrical characteristics of the wind turbine.

Passive solar systems such as solar chimneys need solar radiation in order to work. Therefore, they cannot present stable natural ventilation when solar energy vanishes: to have a more robust and stable condition, solar energy should be stored during the day and released back during the night. Phase change materials can save additional thermal energy during the day and release it during the night in order to facilitate stable ventilation. In this study, a CFD simulation has been performed to investigate the effect of phase-change materials (PCM) utilization in the solar chimney to provide a stable temperature and air flow rate for a guardroom. The simulation was carried out for a whole day in winter in two cases: with and without PCM usage. The results show that use of PCM as an energy storage device significantly enhances the temperature stability of the guardroom.