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Applied Energy, 258 ISSN:0306-2619 ISSN:1872-9118

This study was planned to offer the roadmap for lifecycle clean shipping by addressing the fundamental question of ‘what are the promising energy solutions for the shipping sector?’. This goal was attempted to be achieved by a lifecycle comparative analysis of the viability of three zero-carbon fuels, ammonia, hydrogen, and inland electricity, based on the operational practicality as well as Well-to-Wake environmental impacts. Credible business scenarios were designed with a high-level screening of 27 short-route ferries currently engaged in 26 West-Scotland coastal routes. Then a series of comparative analyses between the diesel and the proposed alternative fuel sources was conducted. While carbon-free fuels are in the early stages of development in the UK, there are various views on how these fuels can be produced, distributed, and used onboard for the clean shipping economy. To determine the optimal energy solutions, all credible scenarios for the upstream pathways for these fuels were developed, based on the current and future prospected UK energy infrastructure and grids. Those scenarios were examined for West-Scotland shipping and extended to the UK targets. Their technical aspects for maritime application were also investigated in consideration of safety, regulation, infrastructural availability, supply chain constraints, barriers, and the downstream emission pathways to their uptake onboard. Ship conceptual designs were briefly conducted to evaluate the systems, technologies, and equipment required for onboard installation to utilise zero-carbon fuels. As a result of the study, when hydrogen was used as a fuel in fuel cells and electricity was supplied as a backup from batteries that store inland power and the solar PV system, GHG emissions were 25.7% of the conventional fossil fuel-using scenario. In addition, it was confirmed that GWP was 22.2% compared to MGO when ammonia was used as fuel without reforming into hydrogen and backup power was supplied from batteries and the solar PV system. It is ...

MgO/H2O/Mg(OH)2 chemical heat storage of waste energy from industrial processes is a promising technology in view of a more efficient use and saving of primary energy sources. A new approach was used to develop a hybrid heat storage material made of magnesium hydroxide (Mg(OH)2) and exfoliated graphite (which is used to improve the heat transfer with its high thermal conductivity). Mg(OH)2 nanoplatelets were directly grown on graphite surface via a deposition–precipitation method to increase the compatibility between the two materials. The material thus obtained, named DP-MG, was experimentally tested to determine its heat storage and output capacities. An improvement of the material efficiency was obtained with a higher storage capacity at lower reaction temperature and a higher heat output rate.

Synthesis of a chemical or energy system is very creative. Only a designer with special skills can accomplish it. Thermodynamics has a hierarchical structure and each level of the structure has its own application to process system synthesis.

Geoenergy sources will continue to be mainstays of the world’s energy mix for many years to come, but the technological and business realities behind these energy sources are changing in two fundamental ways. First, with much of the world’s “easy oil” already consumed, the companies behind geoenergy will have to use increasingly sophisticated technologies to find and deliver these energy sources to the market. Second, the expectations placed upon the geoenergy sector by many of its stakeholders have grown considerably with regards to environmental stewardship, safety, and human welfare. In the face of these kinds of challenges, the industry will require an increasing degree of technological and commercial sophistication to continue to be a part of the world’s sustainable energy mix. Blockchain has emerged as a promising innovation that could potentially play an important role in delivering the kinds of technological and commercial capabilities that the geoenergy sector will need to achieve these ends. In spite of the myriad ways that blockchain could potentially improve the efficiency and sustainability of the geoenergy industry, however, the technology is still evolving, and a few barriers stand in the way of its widespread deployment. This paper puts forward case study evidence from the Intel Corporation and the Energistics Consortium showing what the geoenergy sector can learn about blockchain from other industries, and highlights that the absence of data standards and interoperability has contributed to blockchain’s failure to deliver significant value in the geoenergy domain thus far.

Abstract To facilitate building integration with solar cooker for household, a solar cooker based on a fixed-focus Fresnel lens solar concentrator/cavity receiver system was proposed. To increase the system optical efficiency, the cavity receiver with bottom reflective cone was used as a fixed receiver. Expecting to optimize the system and receiver of better optical performance, the effects of receiver parameters on it were studied. To evaluate the effects, a significance test of key factors was conducted. Comparative analysis of fixed-focus food cooking system was undertaken. The analysis shows that average optical efficiencies using cavity receiver with bottom reflective cone of spherical, cylindrical, conical are 72.23%, 68.37% and 76.40%, respectively, while that of their corresponding conventional cavity receivers are 68.49%, 31.91% and 74.61%. The former significantly increased 3.74%, 36.46% and 1.79%, respectively. Moreover, cavity receiver with bottom reflective cone angle 90° is able to hold a higher amount of incoming energy from concentrator, compared to other three angles. Increasing the bottom reflective cone reflectivity and cavity receiver surface absorptivity can improve optical efficiency. In addition, the cavity receiver surface absorptivity and concentrated sunlight incidence angle have the most significant influence on the optical efficiency and flux uniformity, respectively. The conical cavity receiver with bottom reflective cone is the most suitable one for system. This work is expected to be useful for further optimization of solar concentrator/cavity receiver system.

Abstract The reliability of proton exchange membrane fuel cell (PEMFC) tightly depends on the suitable operating conditions during dynamic operations. This study proposes an optimization framework to determine the optimal control strategy for PEMFC cold starts underpinned by a novel artificial intelligence method, to improve cold-start capacity and shorten the start-up time. The effects of constant and dynamic currents on PEMFC cold starts under various initial temperatures are studied. The numerical results from a developed PEMFC dynamic model show that the constant current slope strategy (CCSS) is more efficient than the constant current strategy (CCS) in respect of the cold-start time. In the CCSS study, a too-large current slope can lead to a voltage undershoot and then cause a failed cold start, but a too-small current slope can result in a long start-up process in the investigated range of the operating conditions. A data-driven model is developed for dynamic prediction and real-time optimization during the cold start by a semi-recurrent sliding window (SW) method coupled with artificial neural networks (NN) with the simulation data. Based on this NN-SW model, the specific safety–critical operating condition curve under the CCSS has been identified. A real-time adaptive control strategy (RACS) is further proposed to optimize the operating current during the PEMFC cold starts with various initial temperatures. Compared to the optimal CCSS, RACS proves to be more robust and efficient for PEMFC cold-start startups. Based on RACS, the start-up time for an initial temperature of −20 °C can be cut down by 26.7%. Furthermore, the ice predictions by the NN-SW model are also tested and the results are satisfying with an average R2 = 0.9773.