• Energy Research

Abstract This study focuses on the control of dimethyl ether (DME) autothermal reforming (ATR) process integrated with proton exchange membrane fuel cells to provide adequate external power for an on-board reformer hydrogen vehicle. ATR reaction was made over Pd–Zn/γ-Al2O3 catalyst, which provides higher selectivity to the hydrogen due to its good oxidation and reforming activities. Catalyst activity was tested experimentally by varying the temperature. The hydrogen volume fraction is close to 45% at the optimal temperature of 400 °C. The objective of the process control scheme was to control the ATR reactor's temperature and the hydrogen production rate. A combination of the feedforward control and the closed-loop control (based on PID control) was applied wherein the DME, and air flow rates were adjusted automatically, and steam was supplied excessively to promote reactions. Due to its good oxidation and reforming activity, it had a high selectivity to hydrogen. The experimental results showed that the volume fraction of hydrogen in the hydrogen-rich gas is close to 45% at the optimum temperature of 400 °C. The control strategy could ensure that the hydrogen production rate changed with the change of fuel cell load and did not affect the temperature of the autothermal reformer. In this way, the stable operation of the reformer was realized, and the fuel cell had a sufficient supply of hydrogen.

Abstract The performance degradation of proton exchange membrane (PEM) fuel cells is inevitable in real-time application. In particular, water management issues are related to the optimization design and the stable operation of the fuel cell system. The investigation of the mass transportation of an open-cathode PEM fuel cell based on a three-dimensional numerical model is emulated using computational fluid mechanics (CFD). The unified finite element analysis for the coupled phenomena of the charge transport, mass transport, and electrochemical reactions is discussed in this work. The simulation results are observed and compared with other experimental observations and various physical fields have shown uneven distributed inside of the fuel cell due to the single-direction gases transfer strategy. Therefore, in this study, a strategy based on interchangeable anode inlet and outlet is proposed to alleviate the uneven distribution of internal physical fields. Moreover, the optimized periods of inlet and outlet exchange are studied by comparing the experimental results.

Considering the vulnerable climatic conditions in most parts of the planet, a successful transition toward a carbon-free future is a critical challenge worldwide. In this respect, around 35% of the world’s total greenhouse gas emission (GHG) is associated with the power sector (especially electrical energy). To this end, a vast of electrical energy has been used by the people in buildings. Specifically, a significant amount of energy in buildings is used for heating, cooling, and ventilation. While the available literature highlights the importance of neat, clean, and green electrical energy for the decarbonization of society, a critical gap exists in such literature. That is, most of the literature under this stream deals with the supply side (production) of electrical energy, while the demand side (consumption at an individual level) was neglected. To bridge this critical knowledge gap, this study investigates how the CSR engagement of a hotel organization can promote the energy-related pro-environmental behavior (ERPEB) among the employees with the intervening effect of employees’ environmental commitment (EMEC) and Green intrinsic motivation (GRIM). Further, the conditional indirect role of altruistic values was also tested in this study. The data were collected from different hotel employees in Pakistan with the help of a self-administered questionnaire. We tested the hypothesized relationship through structural equation modeling (SEM). The results confirmed that CSR can be a potential motivator to impact the ERPEB of employees, while EMEC and GRIM mediated this relationship significantly. The findings of this study also confirmed the conditional indirect role of altruistic values. These findings offer various theoretical and practical contributions which are conversed in detail.

An optimal anti-lock braking control strategy using nonlinear variable voltage charging scheme for an electric-wheel vehicle is developed with aim of improving energy recovery efficiency on the premise of vehicle safety under the critical braking situation. A variable voltage charging control scheme is proposed with its operational principles to obtain maximum energy recovery as well as to balance the energy differences of each battery cell during the anti-lock braking. Given the nonlinearity of in-wheel motor, the nonlinear variable voltage charging control law is obtained on the basis of parameters fitting via experimental data. An ideal regenerative braking torque calculated by the nonlinear variable voltage charging control law is set as one of the disturbance vectors and an optimal sliding mode–anti-lock braking control strategy is developed to provide optimal hydraulic pressure for anti-lock braking system. In this manner, the torque allocation process is omitted by using a compensation control of the hydraulic braking torque. Simulation results corroborate the effectiveness of the proposed optimal anti-lock braking control strategy with higher energy recovery efficiency.

Energy management strategy (EMS) has a great impact on securing fuel cell durability, battery charge sustenance, and fuel saving in fuel cell hybrid electric vehicles (FCHEVs). This study aims to develop EMS that can be applied in real-time to satisfy above conditions. Real time power separation was performed using rule-based EMS. A genetic algorithm (GA) was implemented to calculate the optimal battery charge/discharge criterion that simultaneously satisfies the minimum hydrogen consumption rate, battery charge rate preservation, and high fuel cell efficiency. The battery charge/discharge parameter values vary according to driving patterns, and in this paper, typical suburban, urban, and highway driving conditions are considered. For the real-time application of this research method, the effectiveness was demonstrated by applying the driving conditions of unknown patterns. The effect on the initial battery SOC on EMS was analyzed, and in order to verify the superiority of this method, it was compared and analyzed with EMS results using dynamic programming and fuzzy logic under the same driving cycles. The effectiveness of this research method was verified through simulation, and it was confirmed through experiments for real-time application. Since there is a limit to the experiment using an actual fuel cell vehicle, the experiment was performed using a fuel cell and battery. This method can be applied to real fuel cell vehicles in the same way.