A detailed review was conducted to explore waste cooking oil (WCO) as feedstock for biodiesel. The manuscript highlights the impact on health while using used cooking oil and the scope for revenue generation from WCO. Up to a 20% blend with diesel results in less pollutants, and it does not demand more modifications to the engine. Also, this reduces the country’s import bill. Furthermore, it suggests the scope for alternate sustainable income among rural farmers through a circular economy. Various collection strategies are discussed, a SWOC (strength, weakness, opportunity, and challenges) analysis is presented to aid in understanding different countries’ policies regarding the collection of WCO, and a more suitable method for conversion is pronounced. A techno-economic analysis is presented to explore the viability of producing 1 litre of biodiesel. The cost of 1 litre of WCO-based biodiesel is compared with costs Iran and Pakistan, and it is noticed that the difference among them is less than 1%. Life cycle assessment (LCA) is mandatory to reveal the impact of WCO biodiesel on socio-economic and environmental concerns. Including exergy analysis will provide comprehensive information about the production and justification of WCO as a biodiesel.

It is a well-known fact that automotive industries in every country are shifting towards electric vehicles (EVs) and in the days to come it is expected that the industry will become dominated by them, along with hybrid electric vehicles (HEVs). Unfortunately, the acceptance of EVs for mobility is affected by its poor range per charge. Thus, energy optimization and waste energy recuperation are currently in need. A promising method to recover energy that is lost during vehicle deceleration is regenerative braking, which extends the range of a vehicle by recovering the kinetic energy from braking and using it to recharge the battery. However, the intensity of the charging–discharging rate and the operating temperature of lithium–ion (Li–ion) batteries make them vulnerable to failure, making the rate of current delivered to the battery by regenerative braking a serious concern. Therefore, the focus of this review article is on how regenerative braking affects battery life and the precautions being taken to safeguard the battery against increased charge during regenerative braking. In this review paper, various research articles are referred to in order to examine how regenerative braking affects battery life. It is concluded that charging current obtained from long-term regenerative braking is the prominent factor in battery deterioration, regardless of the current intensity. Additionally, the rate of lithium plating is increased if the temperature and state of charge (SOC) are outside of the ideal range. By lowering the depth of discharge (DOD) and using shorter recharging times, higher levels of regenerative braking will extend a battery’s lifecycle even at high SOC and temperature.

Proton exchange membrane fuel cells are a prime choice for substitute electricity producers. Membrane electrode assembly (MEA), bipolar electrodes, and current collectors belong to only a limited number of primary parts of the proton exchange membrane fuel cell (PEMFC). Bipolar plates are among the most famous elements in the fuel cell; they are responsible for the electrochemical reaction, as well as the flow of gases from one bipolar plate to another. A bipolar plate is to be a good electro-conducting, non-corrosive, and a high mechanical strength product. The attainability of the specification is achieved by graphite and metallic materials, each one having its own merits and demerits that are discussed in this article. Likewise, making the second pass for the flow pattern is equally important for the cell to have good performance and efficiency. The emergence of innovative and new bipolar plate designs has caused the achievement of high performance of these plates. The present review article principally focuses on the experimental study of diverse flow fields in the design of PEMFC and on the influence of various geometrical properties on the general operation of fuel cells made of PEMFC, and also on the manufacturing procedure utilized for building contemporary fuel cells.

The operation of steam boilers with high efficiency requires control of thermo-hydraulic and strength parameters in the on-line mode. During operation under transient conditions, there are significant temperature differences over the circumference of the horizontal pressure vessels. This occurrence is caused by the different values of heat transfer coefficients on the inner surface of the boiler drum in the water and steam region. Large thermal stresses can occur in partially filled horizontal vessels. This takes place in large steam generator drums, superheater headers, and steam pipelines. The paper presents a method for determination of thermo-flow parameters for steam boilers. This method allows performing the calculations of the boiler furnace chamber and heating flow rates absorbed by superheater stages. These parameters are important for monitoring the performance of the power unit and determining the degree of the furnace chamber slagging. Knowledge of these parameters allows determining the degree of the furnace chamber slagging. The calculation can be performed in online mode and use to monitoring of steam boiler. The presented method allows to the operation of steam boiler with high efficiency.

Two methods for monitoring the thermal stresses in pressure components of thermal power plants are presented. In the first method, the transient temperature distribution in the pressure component is determined by measuring the transient wall temperature at several points located on the outer insulated surface of the component. The transient temperature distribution in the pressure component, including the temperature of the inner surface is determined from the solution of the inverse heat conduction problem (IHCP). In the first method, there is no need to know the temperature of the fluid and the heat transfer coefficient. In the second method, thermal stresses in a pressure component with a complicated shape are computed using the finite element method (FEM) based on experimentally estimated fluid temperature and known heat transfer coefficient. A new thermometer with good dynamic properties has been developed and applied in practice, providing a much more accurate measurement of the temperature of the flowing fluid in comparison with standard thermometers. The heat transfer coefficient on the inner surface of a pressure element can be determined from the empirical relationships available in the literature. A numerical-experimental method of determination of the transient heat transfer coefficient based on the solution of the 3D-inverse heat conduction problem has also been proposed. The heat transfer coefficient on the internal surface of a pressure element is determined based on an experimentally determined local transient temperature distribution on the external surface of the element or the basis of wall temperature measurement at six points located near the internal surface if fluid temperature changes are fast. Examples of determining thermal and pressure stresses in the thick-walled horizontal superheater header and the horizontal header of the steam cooler in a power boiler with the use of real measurement data are presented.

Equivalent circuit modelling (ECM) is a powerful tool to study the dynamic and non-linear characteristics of Li-ion cells and is widely used for the development of the battery management system (BMS) of electric vehicles. The dynamic parameters described by the ECM are used by the BMS to estimate the battery state of charge (SOC), which is crucial for efficient charging/discharging, range calculations, and the overall safe operation of electric vehicles. Typically, the ECM approach represents the dynamic characteristics of the battery in a mathematical form with a limited number of unknown parameters. Then, the parameters are calculated from voltage and current information of the lithium-ion cell obtained from controlled experiments. In the current work, a faster and simplified first-order resistance–capacitance (RC) equivalent circuit model was developed for a commercial cylindrical cell (LGM50 21700). An analytical solution was developed for the equivalent circuit model incorporating SOC and temperature-dependent RC parameters. The solution to the RC circuit model was derived using multiple expressions for different components like open circuit voltage (OCV), instantaneous resistance (R₀), and diffusional parameters (R₁ and C₁) as a function of the SOC and operating temperature. The derived parameters were validated against the virtual HPPC test results of a validated physics-based electrochemical model for the voltage behavior. Using the developed RC circuit model, a polynomial expression is derived to estimate the temperature increase of the cell including both irreversible and reversible heat generation components. The temperature predicted by the proposed RC circuit model at different battery operating temperatures is in good agreement with the values obtained from the validated physics model. The developed method can find applications in (i) onboard energy management by the BMS and (ii) quicker evaluation of cell performance early in the product development cycle.