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The influencing degree of different factors on terminal energy consumption of public building varies distinctly. If the actual measured terminal energy consumption is directly analyzed, the comparison basis is often inconsistent, which may lead to errors of results. In order to evaluate the energy consumption based on a unified standard, eliminating the interference of influencing factors, the standardization and revision of the measurement value of the terminal energy consumption is necessary. By considering domestic public building samples of different climate regions as research objects, this research has introduced a dimensionality reduction and integration method for evaluating influencing factors that could affect the terminal energy consumption of public buildings based on principal component and clustering analysis. Then, the quantitative mathematical expressions of the relationship between terminal energy consumptions and influencing factors were established through multiple linear regression fitting, formulating the standardized mathematical model of the terminal energy consumption of public buildings. According to the energy consumption standardized model, the evaluation approach was provided and scored based on mode analysis method. This approach can evaluate terminal energy consumption level and energy efficiency potential, analyzing the level of terminal energy consumption of public buildings in China.

Abstract This study evaluates the performance of 75 clear-sky global irradiance models against 75 ground stations worldwide covering five major Koppen-Geiger climate classifications and overall global performance. After quality control, clear-sky detection and data-availability criteria, there are 4.36 million 1-min valid global horizontal irradiance (GHI) data points for evaluation. This study represents the most encompassing evaluation of its kind in terms of number of models assessed, number of ground stations used, most consistent selection of input variables in terms of temporal and spatial resolution, also using the most rigorous and fair performance assessment criteria and suitable ranking system. A statistically rigorous Principal Component Analysis (PCA) ranking procedure is proposed to replace the conventional ordering method based on single and simple statistics. In particular, it is demonstrated that all 13 error metrics contribute to the variance of GHI estimation and thus must all be accounted for in the ranking procedure. The best performing models in each climate zone of equatorial, arid, temperate, cold and polar are REST2v9.1, REST2v9.1, MAC2, REST2v5 and CLS, respectively. Globally, the top three performing models are MAC2, REST2v5, and REST2v9.1. Many models appear to suffer from over-fitting empirical relationships to training data, resulting in inconsistent worldwide performance. Furthermore, six different formulations of the Linke Turbidity factor (TL) are evaluated through its application to five clear-sky models that require it as an input. The best globally performing TL formulations are either by Ineichen or Gueymard when combined with four of the five Linke-dependent clear-sky models, whilst the Grenier formulation performs best with the Ineichen & Perez model. Significant performance variation is observed depending on the TL formulation selected, hence, careful selection is required for an optimal application. The model codes are available in R [1].

Abstract Dolomite, a naturally occurring Ca-based sorbent, shows superior recycling stability in carbonation/calcination cycles for CO2 capture. However, the separation between Ca and Mg in sorbent during recycling weakens the resistance for sintering from MgO, leading to a drastic reduction in the CO2 carrying activity (spent sorbent). This paper presents a novel method for the reactivation of spent dolomite sorbents. Notable activity recovery is achieved by ball milling of the spent sorbent with H2O and dry ice. Powder X-ray diffraction (XRD) results confirm the transformation from oxide (CaO/MgO) to carbonate (CaCO3/CaMg(CO3)2), so that the segregated Ca and Mg in spent sorbent are re-mixed at the atomic level, which is mainly responsible for this effective reactivation. Water plays an irreplaceable role in this process by providing a liquid environment to accelerate the diffusion of the reactants and ionic reactions. In addition, thermogravimetric analysis was carried out on a series of samples with different ball-milling times to determine the suitable reactivation conditions for CO2 capture.

Abstract Hydrogen is considered a potential game changer for world energy systems and a solution to climate change concerns, as it generates zero waste and it is suited for power generation and transportation. Despite its several advantages, there are significant technical challenges in deploying a stable hydrogen economy including improving its process efficiencies, lowering production costs, maintaining cost-effective transmission and distribution, and exploiting inexpensive and sustainable feedstocks. In this context, a detailed study was conducted to analyze the production sources, technologies, storage and transport systems, and global potential exportable feedstocks to produce hydrogen. A comprehensive analysis of current hydrogen production technologies with their energy efficiencies and hydrogen selling prices was reported in this study. Various hydrogen production technologies with their capital investments and CO2 emissions were also presented. Potential feedstocks for hydrogen production were identified and analyzed through a product space model, which characterizes a network of global exportable products based on their similarities and productive knowledge. It was established that the hydrogen production feedstocks and sources currently used are primarily available in six countries: the United States of America, France, Russia, Sweden, the Netherlands, and Spain. Broadly, the results revealed that the United States of America and Russia shared the highest hydrogen feedstock exports, indicating a higher probability of hydrogen production in these countries. Except for Russia, all the studied countries fell in the most desired quadrant, indicating that they can move in all product space directions to exploit unexplored hydrogen feedstocks for better sustainable economic growth.

Abstract This paper presents a conceptual study of a solar PV integrated refrigeration system for a cold storage facility based on the conventional vapor compression system for banana fruit. In the first stage, the conventional system has been thoroughly analyzed. Mathematical modelling has shown that the condenser is oversized, while the evaporator was undersized. Furthermore, the air-conditioning compressor was also found to be oversized by approximately 12 kW after an evaluation at no-load and full-load conditions. In the second stage, the optimized system with reduced consumption was integrated to a solar PV field. The solar field sizing, and performance optimization of the proposed PV hybrid refrigeration system was accomplished in PV*SOL tool. The simulations demonstrated that with a 170 m2 solar field, an optimized PV hybrid refrigeration system can achieve 58.1% solar fraction at a performance ratio of 59.2%, under given climatic conditions. With net metering, the hybrid system shows a high economic feasibility with the payback period of 5.2 years. The comprehensive methodology and all-inclusive results are valuable to generate explicit recommendations for repowering along with renewable integration of cold storage facilities operating in the region.

Abstract Hydrogen fuel cells are received increasingly wide attention in order to develop green ships and reduce greenhouse gas emissions in the field of waterway transportation. Metal hydrides (MHs) can be used to store hydrogen for green ships due to their high volumetric storage capacity and safety. Various measures should be considered in the design and manufacture process of the MH reactor to strengthen its performance of heat and mass transfer and obtain an acceptable hydrogen storage capacity. In this work, LaNi5 hydride is used as the hydrogen storage material and packed in the reactor. A basic axisymmetric numerical model for the hydrogen storage system without a heat exchanger has been developed and proved to be effective through the comparison between its simulation results and the published data during dehydriding. A hybrid heat exchanger, which is consisted of a phase change material (PCM) jacket and a coiled-tube, has been applied into the hydrogen storage system to relieve the thermal effect of MH in the dehydriding process on system performance. Effects of the heat transfer coefficient between the circulating heating water in the coil-tube and the MH bed, the temperature of circulating heating water and the pressure at the outlet on the dehydriding performance have been investigated. Based on parametric study, the relationships among the average dehydriding rate, the heat transfer coefficient, the heating water temperature and the outlet pressure have been found and fitted as simple equations. These fitted equations can be considered as a reference, which provides an important method to effectively control the dehydriding rate in order to satisfy the fuel requirement of the power unit and ensure the safe navigation of green ships in the future.

Abstract This study presents a detailed kinetic investigation into ultra-rich oxidation of H 2 S-CH 4 under high temperature (900–1250 °C) and ambient pressure. Effects of temperature, initial H 2 S/CH 4 ratio and equivalence ratio (Φ) on reactants conversions and products distributions were experimentally studied in a tubular flow reactor and kinetically analyzed by CHEMKIN software. A detailed kinetic mechanism involving 85 species and 515 reactions has been developed and validated using reference data for H 2 S-CH 4 decomposition and results from extended experimental conditions involving the O 2 addition. For H 2 S-CH 4 system, conversion of H 2 S increased steady with the rising temperature while reactivity of CH 4 was weak at temperature below 1000 °C. At temperature higher than 1000 °C, conversion of CH 4 increased rapidly and devoted further formation of H 2 and CS 2 mainly via reacting with H 2 S decomposition products. The H 2 production efficiency was negatively associated with initial H 2 S fraction as H 2 S decomposition was dominant H 2 source within 1150 °C. The stoichiometric ratio for H 2 S/CH 4 merely showed its advantage in H 2 production at higher temperature under which CH 4 reached its equilibrium conversion swiftly. Introduction of little amount of O 2 (Φ = 6 or higher) accelerated the whole reaction process and triggered H 2 S partial oxidation and H 2 formation at lower temperature. CH 4 explicitly showed inferior position in oxidation competition with H 2 S and maintained poor conversion at temperature below 950 °C. The results of rate of production (ROP) analysis at condition without O 2 showed that CH 4 reactivity showed dependence on free S radical via S + CH 4 = SH + CH 3 , and the formed CH 3 was mainly converted via reacting with SH and H radicals. CH 3 could be concurrently reverted to CH 4 via reactions with H 2 S and H 2 . O 2 activated the whole system by forming chain branching radicals O and OH. These radicals promoted H 2 S and CH 4 conversions to form richer S, H and CH 3 radicals. SH + CS = CS 2 + H was important for CS 2 formation and with presence of O 2 , CS 2 was likely to be consumed via oxidation reactions. Finally reaction pathways for H 2 S, CH 4 conversion and H 2 , CS 2 formation were presented.

This work was aimed to comprehensively evaluate the potential for sustainable development of China's shale gas industry. It will contribute to the sustainable development of China's energy and economic. Factors of resource, technology, economy and environment were selected to develop the DPSIR framework evaluation indicators in system for shale gas based on the previous research. Next, The PPFCI (projection pursuit fuzzy clustering model) technique was developed by combining the projection pursuit model with a fuzzy clustering iterative model. So that it can deal with the multi-source, high-dimensional, fuzzy data of the proposed evaluation indicators. And then, the RAGA (accelerated genetic algorithm based on real coding) algorithm was developed to run the PPFCI technique. The results show that core technical capability, investment in projects of prevention of geological disasters, and ecological environment damage indicators were the key factors affecting the sustainability of China's shale gas industry. The potential for sustainable development of China's shale gas industry was relatively low. And it was unbalanced in different provinces. The potential for sustainable development of the southwest region was better than the northwest region. Among them, the development of Sichuan was more stable than Chongqing, with a 99% probability of maintaining a stable and sustainable development state, while Chongqing province has a 15%-20% probability to fluctuate towards the poles.