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To ascertain energy availability and system performance, a comprehensive understanding of the systems' degradation profile and impact on overall plant reliability is imperative. The current study presents an integrated Failure Mode and Effects Analysis (FMEA)–Markovian algorithm for reliability-based instantaneous energy performance prediction for thermal energy systems. The FMEA methodology is utilized to identify and categorize the various failure modes of the gas turbines, establishing a reliability pattern that informs overall system performance. Meanwhile, the Markovian algorithm discretizes the system into states based on its operational energy performance envelope. The algorithm predicts instantaneous energy performance according to upper and lower bounds criteria. This integrated methodology has been subjected to testing in three case studies, yielding results that demonstrate improved reliability and instantaneous energy performance prediction during system degradation. It was observed that after 14 years of operation, the likelihood of major failures increases to 79.6%, 88.7%, and 82.8%, with corresponding decreases in system performance reliability of 10.1%, 4.5%, and 7.8% for the Afam, Ibom, and Sapele gas turbine plants, respectively. Furthermore, the percentage of instantaneous mean power performance relative to the rated capacity is 37.9%, 35.1%, and 46.3% for the three gas turbine plants. These results indicate that the Sapele thermal power plant performs better relative to its rated capacity. Overall, this integrated methodology serves as a valuable tool for monitoring gas turbine engine health and predicting energy performance under varying operating conditions. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell vehicle (HFCV) technology poses great promise as an alternative to significantly reduce the environmental impact of the transport sector's emissions. However, hydrogen fuel cell technology is relatively new, therefore, confirmation of the reliability and safety analysis is still required, particularly for fire scenarios within confined spaces such as tunnels. This study applied the computational fluid dynamics (CFD) simulations in conjunction with probabilistic calculation methods to determine the associated thermal risk of a hydrogen jet fire in a tunnel and its dependency on scenarios with different tunnel slopes, longitudinal and transverse ventilation velocities, and fire positions. A large-scale model of 102 m in which the effects of outlined parameter variations on the severity of the fire incident were analysed. It is found that both tunnel ventilation techniques and slope were critical for the effective ejection of accumulated heat. With ventilation playing a primary role in the ejection of heat and gas and slope ensuring the stability of the ejected heat, probabilities of thermal burns were found to be reduced by up to approximately 35% with a strong suggestion of critical combinations to further reduce the dangers of hydrogen tunnel fires. [ABSTRACT FROM AUTHOR]

Attention to photovoltaic (PV) cells to convert solar irradiation into electricity is significantly growing for domestic usage and large-scale projects such as solar farms. However, PV efficiency decreases on hot days. This paper proposes an effective cooling technique consisting of a 2% nano encapsulated phase change material (NEPCM) slurry and impinging jets (IJs) in a PV system. The impact of five influencing parameters on PV efficiency is studied using a multi-phase volume of fluid (VOF) model encompassing the effects of solar irradiation, latent heat, mass flow rate, number of nozzles, and jet-to-surface distance. The maximum efficiency of 15.82% is achieved under irradiation of 600 W/m2. The latent heat shows a slight improvement at the low particle concentration. Increasing the mass flow rate to 0.12 kg/s enhances the PV output power by 17.32%. While the PV performance is shown to be improved over the increment of the number of nozzles, the jet-to-surface spacing of 5.1 mm records a remarkable PV surface temperature reduction to 33.8 °C, which is the ideal operating temperature for the PV panel. [ABSTRACT FROM AUTHOR]

The high latent heat thermal energy storage (LHTES) potential of phase change materials (PCMs) has long promised a step-change in the energy density for thermal storage applications. However, the uptake of PCM systems has been limited due to their relatively slow charging response, limited life, and economic considerations. Fortunately, a concerted global research effort is now underway to remove these remaining technical challenges. The bibliometric analysis of this review reveals that a major focus is now on the development of nano-enhanced phase change materials (NePCM), which have the potential to mitigate many of these technical challenges for PCM-based thermal energy storage systems. As such, our bibliometric analysis has zeroed in on research in the field of thermal energy storage using NePCMs since 1977. It was found that journal articles were the most frequently used document type, representing 79% of the records and that the pace of new work in this specific area has increased exponentially over these two decades, with China accounting for the highest number of citations and the most publications (168), followed by India and Iran. China has also played a central role in the collaboration network among the most productive countries, while Saudi Arabia and Vietnam show the highest international collaboration level. [ABSTRACT FROM AUTHOR]