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Abstract In the present work, a novel hybrid solar-based smart building energy system is introduced and studied. The system comprises innovative photovoltaic-thermal-cooling (PVTC) panels integrated with hot and cold storages with two-way interaction with electricity, heat, and cooling networks (if any). The proposed system is compared with PV-based systems integrated with battery and heat pump for a case study complex building in Aarhus, Denmark. The comparison is conducted by evaluating the performance and economic indicators and investigating the effect of significant parameters on each scenario via a parametric study. Furthermore, the optimal operating conditions and sizing of the proposed system are determined using the genetic algorithm method considering initial cost and traded energy with local energy networks as the objective functions. The comparison results show that the proposed solution is the most cost-effective scenario with the lowest initial cost of about 457,000 $ and a payback period of 6.6 years. This is mainly due to the simultaneous interaction with electricity/heat/cooling networks as well as the elimination of the battery and the heat pump, which are offered by the proposed scenario. It is shown that, in comparison to PV panels, the PVTC can produce 328.7 MWh and 125.6 MWh extra heat and cooling annually. The scatter distribution of significant parameters shows that the panel area and heat storage capacity are not sensitive parameters, and keeping the cold storage capacity at the lower bound is a techno-economically better option.

Abstract Experimental investigation on pollutant emissions and performance of SI engine fueled with gasoline and iso-butanol–gasoline blends is carried out. Engine was operated at speed range of 2600–3400 r/min for each blend (3, 7 and 10 vol.% iso-butanol) and neat gasoline. Results declare that the CO and UHC emissions of neat gasoline are higher than those of the blended fuels for speeds less than or equal to 2900 r/min; however, for speeds higher than 2900 r/min, we have an opposite impact where the blended fuels produce higher level of CO and UHC emissions than the gasoline fuel. The CO2 emission at using iso-butanol–gasoline blends is always lower than the neat gasoline at all speeds by up to 43%. The engine performance results demonstrate that using iso-butanol–gasoline blends in SI engine without any engine tuning lead to a drop in engine performance within all speed range. Without modifying the engine system, overall fuel combustion of iso-butanol–gasoline blends was quasi-complete. However, when engine system is optimized for blended fuels, iso-butanol has significant oxygen content and that can lead to a leaner combustion, which improves the completeness of combustion and therefore high performance and less emissions would be obtained. Finally, the performance and emissions of iso-butanol–gasoline blends are compared with those of n-butanol–gasoline blends at similar blended rates and engine working conditions. Such comparison is directed to evaluate the combustion dissimilarity of the two butanol isomers and also to emphasize which isomer is a superior fuel for SI engines.

Abstract Biodiesel is an unsurpassed alternative fuel source intended to extend the value to fossil fuels, and the longevity and cleanliness of diesel engines. It reduces the dependence on the foreign fuels and reduces the greenhouse gas emissions due to its closed carbon cycle. The plentiful advantages of biodiesel are overcome by few drawbacks such as the increase in the nitrogen oxide emission, its incompatibility with cold weather conditions, and the regular intervals of engine parts replacement such as fuel filters, fuel tanks and fuel lines due to clogging. There is a further scope for enhancement in fuel properties and to overcome the drawbacks by addition of nanoparticles as fuel additives. Recent researches on fuel additives indicated the inclusion of nano-sized particles (metallic, non-metallic, oxygenated, organic and combination) with diesel-biodiesel fuel emulsion. The results achieved demonstrated an improvement in the thermophysical properties, enhancement in the heat transfer rate, and stabilization of the fuel mixtures. Also, there was an increase in the engine performance parameters and reduction in the exhaust emissions depending on the dosage of nanofluid additives. This review paper includes the methods for preparation of nanofluids, the stability enhancement of nanofluids by various technique, several characterization methods to find the chemical bonding, nanoparticle shape, and size, dispersion of nano-additives in liquid fuel, the health effects, and applications of nanoparticles in the automotive industry. The numerous literature reviewed had some degree of indistinct and inconsistent outcomes. The experimental results from the various researchers were not generalized to reach a general accord regarding this innovative approach of fuel adulteration. The present work summarizes the literature from most recent articles on nanoparticles as a liquid fuel additive. The effect of dispersion of several nanoparticles on the enhancement in the performance characteristics and reduction in emission of a CI engine fuelled with diesel-biodiesel blends are discussed. The further scope suggests the development of an economically sustainable and feasible nanoparticle additive for diesel and biodiesel fuel. Nevertheless, few obstacles and challenges which have been recognized in this review must be addressed before they can be fully put into practice in the industrial applications.

Abstract Solar photovoltaic plants are widely integrated into most countries worldwide. Due to the ever-growing utilization of solar photovoltaic plants, either via grid-connection or stand-alone networks, dramatic changes can be anticipated in both power system planning and operating stages. Solar photovoltaic integration requires the capability of handling the uncertainty and fluctuations of power output. In this case, solar photovoltaic power forecasting is a crucial aspect to ensure optimum planning and modelling of the solar photovoltaic plants. Accurate forecasting provides the grid operators and power system designers with significant information to design an optimal solar photovoltaic plant as well as managing the power of demand and supply. This paper presents an extensive review on recent advancements in the field of solar photovoltaic power forecasting. This paper aims to analyze and compare various methods of solar photovoltaic power forecasting in terms of characteristics and performance. This work classifies solar photovoltaic power forecasting methods into three major categories i.e., time-series statistical methods, physical methods, and ensemble methods. To date, Artificial Intelligence approaches are widely used due to their capability in solving the non-linear and complex structure of data. The performance analysis shows that these methods outperform the traditional methods. Recently, the ensemble methods were also developed by researchers to extract the unique features of single models to enhance the forecast model performances. This combination produces accurate results compared to individual models. This paper also elaborates on the metrics assessment which was implemented to evaluate the forecast model performances. This work provides information which is beneficial for researchers and engineers who are involved in the modelling and planning of the solar photovoltaic plant.

Abstract Pentanol is a long chain alcohol produced from renewable sources and considered as a promising biofuel as a blending component with diesel or biodiesel blends. However, the lower cetane number of alcohols is a limitation, and it is important to increase the overall cetane number of biodiesel fuel blends for efficient combustion and lower emission. In this consideration, ignition improver additive 2-ethylhexyl nitrate (EHN) were used at a proportion of 1000 and 2000 ppm to diesel-biodiesel-pentanol blends. Experiments were conducted in a single cylinder; water-cooled DI diesel engine operated at full throttle and varying speed condition. The thermal stability of the modified ternary fuel blends was evaluated through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis, and the physic-chemical properties of the fuel as well as engine characteristics were studied and compared. The addition of EHN to ternary fuel blends enhanced the cetane number significantly without any significant adverse effect on the other properties. TGA and DSC analysis reported about the improvement of thermal characteristics of the modified blends. It was found that, implementing ignition improver make the diesel-biodiesel-alcohol blends more thermally stable. Also, the brake specific fuel consumption (BSFC), nitric oxides (NO) and smoke emission reduced remarkably with the addition of EHN. Introducing EHN to diesel-biodiesel-alcohol blends increased the cetane number, shorten the ignition delay by increasing the diffusion rate and improve combustion. Hence, the NO and BSFC reduced while, carbon monoxide (CO) and hydrocarbon (HC) emissions increased slightly.

Abstract Moringaceae is a monogeneric family with a single genus i.e. Moringa. This family includes 13 species. All these species are known as medicinal, nutritional and water purification agents. This study reports, for the first time, on characterization of the biodiesel derived from crude Moringa peregrina seed oil and its blends with diesel. The crude oil was converted to biodiesel by the transesterification reaction, catalyzed by potassium hydroxide. High ester content (97.79%) was obtained. M. peregrina biodiesel exhibited high oxidative stability (24.48 h). Moreover, the major fuel properties of M. peregrina biodiesel conformed to the ASTM D6751 standards. However, kinematic viscosity (4.6758 mm2/s), density (876.2 kg/m3) and flash point (156.5 °C) were found higher than that of diesel fuel. In addition, the calorific value of M. peregrina biodiesel (40.119 MJ/kg) was lower than the diesel fuel. The fuel properties of M. peregrina biodiesel were enhanced significantly by blending with diesel fuel. In conclusion, M. peregrina is a suitable feedstock for sustainable production of biodiesel only blended up to 20% with diesel fuel, considering the edibility of all other parts of this tree.

This research was supported by the Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST).

Abstract The Jerusalem artichoke (Helianthus tuberosus) is a perennial plant which is adapted to wide climatic conditions ranging from temperate to semiarid regions. Its tubers are alternative to potatoes and it can typically produce 18–28 tons of waste foliage from one hectare which can be exploited for bioenergy via pyrolysis. However, the pyrolytic behavior of its waste was never studied. The present study was focused to assess its potential via pyrolysis, kinetics, thermodynamics, and TG-FTIR-MS based study to produce energy and chemicals. The biomass was subjected to thermal degradation at five heating rates (10, 20, 30, 40, 80 °C/min) under an inert environment. The thermograms showed that the highest rate of thermal transformation was achieved at 270–430 °C. The data were subjected to kinetics and thermodynamics analyses using Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Starink and Vyazovkin models. The activation energy (Ea) and pre-exponential factors remained consistent and ranged from 160 to 175 kJ/mol and 1012–1014 s−1 at conversion fractions ranging from α = 0.2 to α = 0.6. The kinetic parameters showed higher statistical confidence with R2 ≥ 0.98 and good agreement among the data obtained through various models. The high heating value (HHV = 18.76 MJ/kg), change in enthalpy (∼ΔH = 150–170 kJ/mol), and Gibbs free energy (ΔG = 158–168 kJ/mol) demonstrated the substantial bioenergy potential of this waste. Moreover, the pyrolytic gases were subjected to Thermogravimetric-Fourier Transformed Infrared Spectroscopy-Mass Spectrometry (TG-FTIR-MS) analyses to identify the nature of products. The detected functional groups showed that the evolved gases contained aldehydes, phenols, carboxylic acids, esters, aromatic hydrocarbons and methane which indicated the substantial potential of this waste to produce energy and chemicals via pyrolysis causing no competition with the food/feed or land for food/feed.

[EN] The European commission is targeting a 15% reduction in CO2 emissions for medium and heavy-duty transportation starting in 2025. Moreover, the next European normative (EU VII) will impose a decrease of 50% for NOx and particulate matter emissions with respect to the current EUVI normative. Meeting these requirements pose a significant challenge to truck and bus manufacturers. Several proposals appeared in the last few years as improve the cabin aerodynamics, decrease the friction losses and improve the powertrain efficiency. The last point involves improving the current combustion systems as well as the transmission and energy management. This work proposes to couple two potential technologies to reduce at the same time the global (CO2) and local pollution (NOx and soot). For this, two truck platforms representative of medium-duty applications (18 ton and 25 ton) are tested using the reactivity controlled compression ignition (RCCI) combustion mode with diesel and gasoline as fuels. In addition, the trucks are electrified to full hybrid technology in a parallel pre-transmission (P2) architecture. A 0D vehicle numerical model is used to evaluate the trucks under four different driving cycles representative of homologation and real driving conditions. The numerical model is validated against on road measurements. The RCCI combustion is modeled by means of a map-based approach with 54 points measured in steady-state conditions. This work presents a complete engine map calibration with measurements up to 350 hp using two combustion modes inside the map (so-called dual-mode dual-fuel). As a baseline, the commercial diesel no-hybrid trucks and the dual-fuel no-hybrid trucks are used. The results show the potential of the dual-mode dual-fuel combustion to achieve ultra-low NOx and soot emissions. In addition, the CO2 target reduction is achieved for several truck platforms and driving conditions due to the hybridization of the driveline. The cycles with large phases of urban driving are the most favorable due to the ability of recovering energy by means of the regenerative braking system and the possibility to avoid large idling phases with respect to the no-hybrid versions. In addition, the decrease of the payload improves the CO2 reduction with respect to the baseline cases. The authors thanks ARAMCO Overseas Company and VOLVO Group Trucks Technology for supporting this research. The authors acknowledge FEDER and Spanish Ministerio de Economia y Competitividad for partially supporting this research through TRANCO project (TRA2017-87694-R). The authors also acknowledge the Universitat Polit`ecnica de Val`encia for partially supporting this research through Convocatoria de ayudas a Primeros Proyectos de Investigacion (PAID-06-18).