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The growing global awareness of social and environmental issues has led investors to prioritize sustainable investments. This study examines the relationship between ten Islamic and conventional sector indices, which include stocks screened for environmental, social, and governance (ESG) factors, across three energy-related fields: renewable energy, energy efficiency, and oil equipment and services. Using a quantile cross-spectral approach, this research finds a high level of long-term synchronization among all energy-related sectors and indices. However, as markets shift from bearish to bullish, the current relationship between energy-related sectors and Islamic and conventional indices weakens. To support the findings in this research and investigate potential financial implications, this investigation applies a causality-in-quantiles approach. The research in this study shows a bidirectional causal relationship between conventional and Islamic indices, particularly in the energy efficiency sector during bearish market conditions. At lower tails, ESG market indices are found to cause renewable energy products, suggesting a hedging mechanism. The findings of this study assert that investments that do not possess any ESG shortcomings are imperative for effectively bolstering renewable energy companies and fostering opportunities for energy efficiency. These conclusions hold considerable ramifications for energy policymakers as they strive to devise more robust financial mechanisms that can provide substantial support to the burgeoning green sector.

This study builds a holistic, transparent life cycle assessment model of a variety of aqueous mineral carbonation processes using a hybrid process model and economic input–output life cycle assessment approach (hybrid EIO-LCA). The model allows for the evaluation of the tradeoffs between different reaction enhancement processes while considering the larger lifecycle impacts on energy use and material consumption. A preliminary systematic investigation of the tradeoffs inherent in mineral carbonation processes is conducted to provide guidance for the optimization of the life-cycle energy efficiency of various proposed mineral carbonation processes. The life-cycle assessment of aqueous mineral carbonation suggests that a variety of alkalinity sources and process configurations are capable of net CO2 reductions. The total CO2 storage potential for the alkalinity sources considered in the U.S. ranges from 1.8% to 23.7% of U.S. CO2 emissions, depending on the assumed availability of natural alkalinity sources and efficiency of the mineral carbonation processes.

One of the major goals of engine designers is the reduction of fuel consumption and pollutant emissions while keeping or even improving engine performance. In recent years, different technical issues have been investigated and incorporated into internal combustion engines in order to fulfill these requirements. Most are related to the combustion process since it is responsible for both fuel consumption and pollutant emissions. Additionally, the most critical operating points for an engine are both the starting and the warming up periods (the time the engine takes to reach its nominal temperature, generally between 80°C and 90°C), since at these points fuel consumption and pollutant emissions are larger than at any other points. Thus, reducing the warm-up period can be crucial to fulfill new demands and regulations. This period depends strongly on the engine cooling system and the different strategies used to control and regulate coolant flow and temperature. In the present work, the influences of different engine cooling system configurations on the warm-up period of a Diesel engine are studied. The first part of the work focuses on the modeling of a baseline engine cooling system and the tests performed to adjust and validate the model. Once the model was validated, different modifications of the engine coolant system were simulated. From the modelled results, the most favourable condition was selected in order to check on the test bench the reduction achieved in engine warm-up time and to quantify the benefits obtained in terms of engine fuel consumption and pollutant emissions under the New European Driving Cycle (NEDC). The results show that one of the selected configurations reduced the warm-up period by approximately 159 s when compared with the baseline configuration. As a consequence, important reductions in fuel consumption and pollutant emissions (HC and CO) were obtained.

Effusion cooling represents the state of the art of liner cooling technology for modern combustors. This technique consists of an array of closely spaced discrete film cooling holes and contributes to lower the metal temperature by the combined protective effect of coolant film and heat removal through forced convection inside each hole. Despite many efforts reported in literature to characterize the cooling performance of these devices, detailed analyses of the mixing process between coolant and hot gas are difficult to perform, especially when superposition and density ratio effects as well as the interaction with complex gas side flow field become significant. Furthermore, recent investigations on the acoustic properties of these perforations pointed out the challenge to maintain optimal cooling performance also with orthogonal holes, which showed higher sound absorption. The objective of this paper is to investigate the impact of a realistic flow field on the adiabatic effectiveness performance of effusion cooling liners to verify the findings available in literature, which are mostly based on effusion flat plates with aligned cross flow, in case of swirled hot gas flow. The geometry consists of a tubular combustion chamber, equipped with a double swirler injection system and characterized by 22 rows of cooling holes on the liner. The liner cooling system employs slot cooling as well: its interactions with the cold gas injected through the effusion plate are investigated too. Taking advantage of the rotational periodicity of the effusion geometry and assuming axisymmetric conditions at the combustor inlet, steady state RANS calculations have been performed with the commercial code Ansys® CFX simulating a single circumferential pitch. Obtained results show how the effusion perforation angle deeply affects the flow-field around the corner of the combustor, in particular, with a strong reduction of slot effectiveness in case of 90 deg angle value.

In the present work, an experimental study on a lab-scale adsorption refrigerator, based on activated carbon/ethanol working pair is reported. An extensive testing campaign has been carried out at the CNR ITAE laboratory, with multiple aims. First, the performance has been evaluated in terms of both COP and Specific Cooling Power (SCP), under different boundary conditions, including both air conditioning and refrigeration applications. Attractive SCPs, up to 180 W/kg and 70 W/kg for air conditioning and refrigeration, respectively, were measured. Under the same conditions, COP between 0.17 and 0.08 were obtained. In addition, different management strategies, namely, heat recovery between adsorbers and re-allocation of phase durations, were evaluated to identify their influence on the system. Both strategies confirmed the possibility of increasing COP and SCP up to 40% and 25%, respectively. Moreover, a design analysis based on the experimental results has been carried out, to suggest possible improvements of the system. The obtained results demonstrated the possibility of employing a non-toxic refrigerant like ethanol reaching performance comparable with other harmful refrigerants like ammonia and methanol.

Abstract The field of energy harvesting holds the promise of making our buildings “smart” if effective energy sources can be developed for use in ambient indoor conditions. Photovoltaics (PV), especially in its thin flexible form for easy integration, become a prime candidate for the aim, if tailored for low-density artificial light. We designed a test system which enabled us to measure the performance of PV devices under compact fluorescent lamp (CFL) and light-emitting diode (LED) illumination at different illuminance levels and compared polycrystalline and amorphous silicon cells with our own flexible dye solar cells (DSCs). Whereas poly-Si cells, with 15% outdoor efficiency, delivered at 200 lux under CFL only 2.8 μW/cm2 power density (and an efficiency of 4.4%), a-Si specifically designed for indoors, gave 5.9 μW/cm2 and 9.2% efficiency under the same CFL conditions (and 7.5% efficiency under LED). However, we show that the customization of flexible DSCs, by simply formulating ad-hoc less-concentrated, more transparent electrolytes, enabled these devices to outperform all others, providing average power densities of 8.0 μW/cm2 and 12.4% efficiencies under 200 lux CFL (more than quadruple compared to those measured at 1 sun), and 6.6 μW/cm2 and 10% efficiency under 200 lux LED illumination.

A power conditioning system with energy storage capability is proposed as a viable solution for improving the quality and the reliability of the electric energy supply. Several tasks can be performed at the same time, such as reactive power compensation, current harmonic reduction, and smoothing of pulsating loads. Moreover, the power conditioning system can operate as an uninterruptible power supply during short time interruptions of the grid supply. The proposed system is a flexible structure that can be coupled to several energy storage devices like batteries, flywheels, supercapacitors, superconductive magnetic energy storage systems. In order to show the power conditioning system performance, experimental tests have been carried out using a flywheel as storage device. The effectiveness of the proposed control system has been successfully verified in several operating conditions of the grid supply and of the load.

Abstract CIEMAT is promoting experiences on heliostats for replacement of damaged facets on CESA-1 field, design of new modules for Phoebus-like plants and innovative high-risk options for the future. Glass-metal facets, stretched membranes, glass fiber and holographic concentrators are being considered in a number of developments.

This article concerns a field study about the use of non-invasive manual lighting and shading control to save energy in listed buildings. The system was chosen to limit cabling and masonry work. The test room consists of an individual office located in a historical building in Southern Italy. The room was retrofitted with two roller shades (semi-transparent and blackout) and six LED-based pendants provided with step-dimming and three Correlated Colour Temperature options. Shading and lighting could be remotely controlled from the desk by six subjects who took part in the test for two weeks each. Behavioural interventions and a set back to default setting at the end of the working day were adopted to improve the test subjects’ energy behaviour. The results show that energy for lighting could be reduced between 15% and 71% compared to European benchmark, with wide range accounting for variability of individual preference and weather conditions. The savings are due to the computer-based work, the communication and engagement campaign, as well as the default settings. The findings suggest that simple manually controlled systems are energy and economic viable solution for listed buildings, since the system accommodates users’ needs, and proper training is provided to the users.