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The effects of six control parameters, intake valve opening timing (IVO), exhaust valve opening timing (EVO), compression ratio (CR), engine speed, intake temperature, and intake pressure on engine output power, indicated specific fuel consumption (ISFC), and nitrogen oxides (NOx) emissions, are analyzed through engine simulation. The six parameters were categorized into two groups based on the degree of influence: high influence (EVO, speed and intake pressure) and low influence (CR, IVO and intake temperature). The relationship between these two groups of parameters and power, ISFC and NOx emissions was explored. Optimization was carried out for each of the two groups of parameters, and the optimization of the high impact parameters resulted in a higher diversity and wider distribution of the solution set. On the other hand, the optimization of the low-impact parameters resulted in a more concentrated distribution of the solution set, while better reflecting the trade-off between the optimization objectives. For the optimal solutions for both sets of parameters, the high-impact parameters provided significant optimization performance compared to the standard operating conditions. Although power and ISFC were optimized, the optimal solution for the low-impact parameter performed poorly with a significant increase in NOx emissions. Therefore, the parameters should be evaluated for optimization using high impact parameters to improve engine performance. [ABSTRACT FROM AUTHOR]

The decarbonisation policies for the EU building stock can improve living conditions, including thermal comfort and lower energy bills. However, these measures may impose financial burdens on low-income households, reducing their disposable income and exacerbating their vulnerability. The current study investigates the impact of decarbonisation policies on the EU's building stock, with a specific focus on Minimum Energy Performance Standards (MEPS), the new Emissions Trading System (ETS2) for buildings, and the phase-out of fossil heating systems. By employing a linear, static latest version of Microsoft Excel (Microsoft 365)-based model and analyzing Eurostat data, this study quantifies the effects of these policies on energy consumption, costs, and necessary investments. Moreover, the study emphasizes their implications for low-income groups using vulnerability indicators. The findings demonstrate that a combination of MEPs, ETS2, and phasing out fossil heating systems effectively reduces energy consumption and costs across most countries. However, implementing ETS2 alone may lead to energy reduction and discomfort for low-income groups without addressing underlying demand-side issues. To address this, this study recommends the implementation of more ambitious MEPs or the provision of additional funding alongside ETS2. The phase-out of fossil fuel boilers emerges as the most cost-effective measure in the medium to long term. While MEPS and the phase-out of fossil fuel boilers improve living conditions, they also impose upfront cost burdens and reduce disposable income for low-income households. Therefore, high subsidy rates and supportive policies are necessary to ensure equitable access to investments. The main recommendations include (a) shifting financing to renewable heating systems for low-income households by 2025, addressing cost issues and policies favouring gas boilers; (b) implementing high-funding rate subsidies for energy efficiency in low-income households before 2025, with technical guidance; (c) prioritising the Energy Efficiency First principle in planning to avoid additional emissions or higher costs for low-income households; and (d) considering the energy behaviour of low-income groups in regulations, employing a combination of policies to achieve desired outcomes and ensure thermal comfort. [ABSTRACT FROM AUTHOR]

Improving the energy efficiency of air conditioners and heat pumps is crucial for reducing the effects of continuously rising energy demands for space conditioning. One of the effective and tested approaches for achieving this goal has been to set energy efficiency benchmarks based on minimum energy performance standards which drive technological innovation and implementation in the market. For heat pumps, a testing and rating procedure that estimates equipment seasonal performance from laboratory measurements forms the technical basis for these standards. However, with current residential heat pumps rating standards, significant differences have been observed between efficiency measured in the lab and actual operational performance in field applications. One of the reasons for this is that with current rating approaches, the test unit native controls are overridden when measuring performance in the laboratory. As an alternative, a load-based testing approach has been developed that captures dynamic interactions of the integrated controls, equipment and building with the goal of better-representing field application conditions. In this paper, a load-based testing approach previously developed for air-conditioners is extended for heat–pump heating-mode and demonstrated for a variable-speed system. Climate-specific heating seasonal performance ratings were determined by propagating the test results through a temperature-bin method. [ABSTRACT FROM AUTHOR]

Increase of energy efficiency is Latvia's national priority and policy instrument that allows reducing consumption of energy and costs, increasing the safety level of energy supply and reducing dependence on import. One of the trends for reducing energy consumption is to increase energy performance of buildings. In compliance with the EU and Latvian political statements, it is required to promote renovation of residential and non-residential buildings. Studies regarding energy performance aspects in the sector of non-residential buildings in Latvia are comparatively rare; however, non-residential buildings form a considerable part of the building stock, and the increase of their energy performance can bring a significant contribution in achieving the national targets. The research analyses the sector of non-residential buildings, their characteristic statistical data, energy consumption and requirements of energy performance standards. To characterise this sector more comprehensively, information on energy performance certificates of buildings issued during the period from 2016 to 2021 has been evaluated, allowing to make general conclusions on the energy performance level of different non-residential buildings and provide proposals for trends to increase their energy efficiency. [ABSTRACT FROM AUTHOR]

Energy renovations of the building stock are a paramount objective of the European Union (EU) to combat climate change. A tool for renovation progress monitoring is energy performance certificate (EPC) labelling. The present study tested the effect of different EPC label classifications on a national database, which comprises ~25,000 EPC values from apartment buildings, detached houses, office buildings, and educational, commercial, and service buildings. Analysing the EPC classes labelling resulting from four different EU methods, we estimated the annual renovation rates, costs, energy savings, and CO2 emissions reduction that would affect the national building stock if each of them was adopted, to fulfil the European Climate Target Plan by the year 2033. The ISO 52003-1:2017 two-point and one-point methods determined a very uneven distribution of renovation rates, from 0.45% to ~9%. Conversely, the Directive 15% recently proposed in COM/2021/802 with uniform rates determined smaller differences and standard deviation, not pushing renovations above 3.70%, namely a rate that once fine-tuned can stimulate realistic, yet effective renovation campaigns. The major differences in renovation rates provided by the studied methods show the need for a harmonized strategy such as the Directive proposal to enable achievement of European targets. [ABSTRACT FROM AUTHOR]

Despite myriads of mathematical and experimental studies using various heat exchanger-metal hydride assemblies, an adept comparison of reactors on standard performance defining parameters, i.e., reactor weight, external energy utilization, and alloy material, are not studied or reported for industrial storage containers and onboard applications. This lacuna is a critical barrier in developing efficacious hydrogen storage reactors for various applications. This article chronicles the 3-D design and optimization of three basic heat exchanger setups of solid-state hydrogen storage systems (shell and tube, spiral tube, and tubular) on critical parameters. For 5 kg LaNi 5 , a tubular design with small tube diameters has resulted in a shorter reaction time (120 s) for 90% saturation at 303 K and 15 bar inlet conditions; however, the reactor's gravimetric density was exceptionally high. In contrast, the reactor with three spiral tubes accomplished an exemplary reaction rate at a reasonable gravimetric density. This spiral arrangement became the base for developing a novel reactor that integrated heat pipes to reduce the sorption time. The proposed design achieved a specific output energy rate of 527 W/kg for 90% saturation in 366 s at a supply pressure of 15 bar, which is 23.7% higher than the reactor without heat pipes. [Display omitted] [ABSTRACT FROM AUTHOR]

Mobile edge computing (MEC) is an emerging paradigm that decreases the computational burden of mobiles by task offloading. MEC is regarded as an effective method to offer computing capacities in close proximities to mobile users. The major issue in MEC is how to offload the heterogeneous task of mobile apps effectively from the user equipment to the MEC host. Some of the existing techniques contain feeble adaptability to new circumstance due to minimum sample effectiveness and require complete retraining. The purpose of MEC is to efficiently solve offloading issues such as network load and latency. In this paper, a deep belief network is proposed for solving the offloading issue in the clusters of numerous service node and several dependencies for a mobile task in huge-scale heterogeneous mobile edge computing. The deep belief network's weight is tuned optimally using Adaptive Harris Hawks optimization (AHHO) algorithm for solving the offloading issue optimally in the MEC environment. An AHHO algorithm is employed to improve the search performances of the standard algorithm. The limitations of the standard algorithm are poor stability among exploitation as well as exploration. Hence, two schemes such as the Gaussian mutation scheme and the cuckoo search are combined so as to form an adaptive Harris hawks optimization to enhance this stability. The task offloading issues are implemented using Google cluster trace and iFogSim. Furthermore, the simulation results depict that the offloading scheme based on the deep belief network-based adaptive Harris Hawks optimization approach has better results with respect to measures such as load balancing, energy consumption, average execution time, and latency than any other approach. [ABSTRACT FROM AUTHOR]

This paper addresses the energy efficiency issue in household appliances, which has led to the establishment of policies at a global level in favor of setting minimum energy performance standards (MEPS), which guarantee end users are able to select more efficient equipment. The countries of the United States, Brazil, Mexico, Chile, and the Community of the European Union were taken as references to review their policies and implementation strategies, in order to be compared with the Colombian panorama (at the market, technical and political levels). This allows the establishment of common aspects and differences related to the determination of energy consumption, adjusted volume, and formalization of efficiency ranges, and in the specific case of domestic refrigeration. Managing to distinguish the most relevant aspects for the successful adoption of these policies in Colombia. It is evident that the implementation of these guidelines has a positive impact on the market of the countries and communities of reference. Similarly, the MEPS are shown as a mechanism to regulate energy consumption in the residential sector. [ABSTRACT FROM AUTHOR]

• Individual effect of acid blocking AEM and monovalent selective CEM in selective ED was studied. • The recovered acid concentration increased by using acid blocking AEM, but limited by high Cu2+ flux. • Monovalent selective CEM further improved the acid concentration by breaking the H+ transfer balance. • Acid concentration was increased with electric current and dilute volume in SED. • H+ concentration difference plays crucial role in improving the current efficiency of SED. Electrodialysis (ED) could concentrate salt solutions, but the leakage of H+ ions across the anion-exchange membrane (AEM) obstructed their application in waste acid recovery. Selective electrodialysis (SED) with acid blocking AEM and monovalent selective cation-exchange membrane (CEM) has the ability of reclaiming acid with high concentration efficiently. This study investigated the individual effect of the two selective ion-exchange membranes by comparing the acid reclamation performance of configurations with standard AEM and CEM (A-C), acid blocking AEM and standard CEM (SA-C) and acid blocking AEM and monovalent selective CEM (SA-SC) for etching solution treatment after diffusion dialysis. Substituting acid blocking AEMs for the standard ones could significantly increase the recovered acid concentration. An acid concentration plateau was reached quickly, but Cu2+ ions transfer through the CEMs continuously due to the low H+/Cu2+ ratio in the dilute of SA-C configuration. The monovalent selective CEM obstructed the migration of Cu2+ through the CEM and broke the balance of H+ migration into and out of the dilute through CEM and selective AEM individually. The configuration of SA-SC has the highest current efficiency and the configuration of A-C has the lowest. The utilization of selective membranes increased the purity of the recovered acid, and decreased the specific energy consumption simultaneously. The acid concentration could be further improved by higher current or enlarged dilute volume in SA-SC configuration. During the ED process, H+ concentration difference between the concentrate and the dilute plays a crucial role on the current efficiency for acid recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] Ghana has been a pioneer in energy efficiency in the sub-Saharan region, becoming the first country to introduce minimum energy performance standards and energy labelling for lighting, air conditioners and refrigerating appliances in 2008. It also introduced an innovative and not yet widely adopted policy of banning the import of used air conditioners and refrigerating appliances, mostly from Europe. While the impact of this policy package has already been assessed in terms of energy savings in Ghana, it is still unclear whether the import ban on used products makes sense in terms of environmental impact. Ghana's ban may seem surprising given that current European product policies in the context of the Green Deal aim to extend the lifetime of products and encourage their reuse to make them more sustainable. In this paper, different scenarios covering new and used refrigerating appliances as well as different end-of-life management options were examined in a life cycle analysis. The results show that exporting used refrigerators from Europe to West Africa increases their environmental impact per functional unit in many categories, even if it extends the lifetime of the product. The informal end-of-life treatment of refrigerators by open burning has a massive impact on human toxicity. As energy consumption during the use phase is the main determinant of most environmental impacts, energy efficiency policies (minimum energy efficiency performance standards and labelling) combined with an import ban on used refrigerating appliances are the best approach to reduce these impacts. It is therefore recommended that the Ghanaian policy package be replicated in other countries in the region, but also that exporting countries take action, as the fight against environmental dumping is a shared responsibility. • Used refrigerators exported to West Africa increase greenhouse gas emissions. • Energy efficiency reduces the environmental impact of refrigerators. • Import ban on used refrigerating appliances is justified. • Informal end-of-life treatment of refrigerators has a major impact on human toxicity. [ABSTRACT FROM AUTHOR]

This paper presents the challenges of increasing the energy efficiency investments in European Union (EU) residential buildings in the context of achieving climate neutrality by 2050. The paper presents the results of the PRIMES buildings model in key energy policy applications to support cost-effective and fair policy making in buildings across Europe. The model covers, in detail, the building sector for all the EU Member States (MS), segmenting the buildings into many categories. The approach proposed includes non-market barriers in conventional microeconomic modelling, which combined with idiosyncratic preferences can capture poor energy efficiency choices and still represent rational behaviours. The model includes a detailed portrayal of policies specific to the sector, comprising economic and regulatory policies as well as institutional measures. The results of the model show that the removal of non-market barriers is of great importance in reducing energy consumption and increasing both the pace and the depth of renovation investment. However, the institutional measures alone are not enough to induce energy efficiency improvement to the scale required to achieve the climate neutrality objectives. Economic (i.e., subsidies) or regulatory measures (i.e., energy performance standards) are also required to decrease emissions and energy consumption in buildings and the paper compares different configurations thereof. The optimum policy mix obviously derives from a compromise among various aims including the cost-effectiveness of the policy budget and the distributional impacts across building and consumer types. [ABSTRACT FROM AUTHOR]

Shallow Geothermal Energy (SGE) systems are emerging as an attractive solution to enhance building energy efficiency and contribute to a low-carbon economy. This research investigates a SGE system comprising 40 boreholes installed in a university building located in Aveiro City under Mediterranean climate conditions. Both the building and the underground soil were monitored during the SGE operation, and EnergyPlus® software was subsequently employed for the integrated dynamic simulation. The building energy model was calibrated using field data, and a good agreement between the measured and the simulated temperatures was archived, with a Coefficient of Variance of the Root Mean Square Error (CVRMSE) below 10 %. The case study model performance was analysed and compared to other alternatives. The impact of the climate on the system performance was investigated by analyzing nine Portuguese cities situated in different climate contexts. A sustainability indicator was proposed, and an initial sustainability assessment was conducted. The results emphasize that the SGE system offered advantages compared to other alternative systems, achieving a 55 % reduction in heating and cooling energy consumption, and mitigating climate change by 405.67 ton of CO 2 per 25-year lifespan. This study can guide further implementation of sustainable geothermal systems in Mediterranean climates. [ABSTRACT FROM AUTHOR]

The improvement of energy efficiency of products is a key pillar of climate and energy strategy in the European Union (EU). The first EU product policies were adopted in the late 1970s, and they have evolved to become a coherent set of implementing measures under framework directives that harmonise and refine the regulatory process. After years of weak implementation, considerable progress in terms of scale and ambition has been achieved in the last decade. In 2020, product mandatory measures covered 50% of the EU total final energy consumption, leading to 46 Mtoe energy savings. This paper describes the available policy instruments to promote energy efficiency and remove the market barriers hindering the penetration of the best performing technologies. It offers a review of the progress made over these last 40 years of EU product policies, describing the Energy Labelling, the Minimum Energy Performance Standards (MEPS), the Ecodesign Directive and the voluntary agreements (EU Ecolabel and Green Public Procurement). Moreover, it highlights the remaining challenges and provides policy recommendations to further exploit the EU potential to save energy from products. • Energy efficiency in products is a key pillar of EU climate and energy strategy. • Despite 40 years of EU product policies, their scale has only improved since 2010. • In 2020, mandatory measures covered 50% of the EU final energy consumption. • By 2030, savings expect to reduce the final consumption by 17%. • Policy orientation to further exploit the energy savings of products is provided. [ABSTRACT FROM AUTHOR]

Building energy consumption forecasting is crucial for energy managers and policymakers. However, acutely predicting the energy consumption of any building is more important in energy efficiency benchmarking of buildings. Energy benchmarking is a precise technique for measuring, tracking, and reducing end-use energy usage of buildings by employing comparative scenarios. Bottom-Up energy consumption assessment has been used in several studies to evaluate a collection of buildings' energy performance to a standard. Traditionally, researchers have used a single approach to predict the energy use of buildings and to conduct benchmarking. However, it has been found that doing so frequently compromises the accuracy of the predicted energy use of buildings. It also has an adverse effect on the buildings' energy benchmarking framework results. This paper will provide an energy benchmarking framework for residential buildings based on the blending techniques of multiple approaches. Over 3000 datasets were gathered from the Indian city of Jaipur. In order to analyse the trends in energy consumption, the data were divided into categories based on economic levels. The data is then subjected to some fundamental statistical analysis, along with several approaches are blended to forecast the energy consumption of the buildings with the highest accuracy. These benchmark levels set guidelines for assessing and recognising strong performance while also identifying underperforming buildings and giving them more priority for energy efficiency improvement. The technique may be used for different metropolitan levels and climatic conditions. [ABSTRACT FROM AUTHOR]

This study designed and fabricated a novel top-lit downdraft gasifier stove (TLDDGS), which was compared with a traditional top-lit updraft gasifier stove (TLUDGS) in terms of modeling and performance. The experimental and simulation results demonstrated that the novel TLDDGS exhibits a downward-flow configuration. The average fuel consumption measured in the experiments was 4.57 ± 0.933 g/min. The average flame temperature from the experiment was 608 ± 43 °C. The TLDDGS mean flame temperature remained stable throughout the experiment. The O 2 , H 2 , CO 2 , CO, CH 4 , and N 2 in the diluted syngas from the experiment were 16.07, 0.33, 0.66, 2.56, 0.34, and 80.04% by volume, respectively. The total suspended particulates and CO in TLDDGS and TLUDGS were 15 and 28 mg/m3 and 335 and 69 ppm, respectively, which are within the limits specified by the local standard. Thus, the developed TLDDGS is a promising alternative for sophisticated cooking applications because of its superior performance in terms of flame stability. • The new design of top-lit downdraft gasifier stove has a partial syngas downward flow direction. • The top-lit downdraft gasifier stove has superior flame stability than the conventional stove. • The top-lit downdraft gasifier stove has less total suspended particulates than the conventional stove. • The top-lit downdraft gasifier stove has emission performance according to the standard. • The simulation well explained the mechanism of the top-lit downdraft gasifier stove. [ABSTRACT FROM AUTHOR]

Given the significance of carbon emissions from the existing building stock, this paper aims to provide an international comparative analysis of pioneering policies on minimum energy efficiency standards in the Scottish, English/Welsh, Dutch and French commercial real estate sectors. These are the four national policy regimes to employ these policy instruments to date with varied timelines spanning from 2009 to 2050. The methodological approach employs a document review of policy texts produced by policy makers and other stakeholders. The four policy regimes are evaluated in terms of their policy design focussing on minimum performance standards, forward guidance, scope and exemptions. A key finding is that, given the range of intervening factors, side-effects and uncertainties, there are difficult choices in striking a balance between phasing implementation, providing forward guidance and adjusting policy in response to evaluation. Whilst it was initially expected that most European Union jurisdictions would default to an Energy Performance Certificate related standard, our findings show that there has been a shift towards standards that are linked to actual rather than modelled energy consumption. However, for leased stock where the owner may have limited operational control, the separation of owners' responsibility for compliance and the users' responsibility for operations makes designing consumption-based instruments more challenging. It is concluded that a central issue in policy design has been the trade-off between minimising the financial costs to property owners and occupiers of complying with performance thresholds and maximising reductions in energy consumption. There is growing recognition that regulatory economies of scale may be achieved by targeting large properties which allows for a large proportion of the total area of the stock to be covered whilst exempting a large proportion of transactions or properties. • Policy makers use MEES to improve the energy efficiency of the worst building stock. • Significant policy divergence is observed across the four national policy regimes to date. • MEES should be based on actual energy consumption rather than design-based metrics. • The separation of ownership and use is a barrier to MEES linked to actual consumption. • Regulatory economies of scale may be achieved by targeting large properties. [ABSTRACT FROM AUTHOR]

In 2007 was settled the first minimum energy performance standards for air conditioners in Brazil. After more than 14 years since the first regulations and looking upon future perspectives, this paper presents a review of regulatory developments in the country and an assessment based on scenario simulation to verify potential impacts of new minimum energy performance standards for air conditioners. The methodology employed is a bottom-up approach designed to estimate the energy consumption of air conditioners. A spreadsheet-based computational tool was developed to perform sensitivity analysis of key parameters such as ownership rate, average temperature and cooling degree days. The results show a significant energy savings potential that could be captured through a minimum energy performance standards revision. For the scenarios simulated these savings potential would reach up to 417 TWh, with respective greenhouse gases emissions reduction that would be 249 million tons, over the period from 2023 to 2040. An economic analysis of minimum energy performance standards impact is also provided and indicate that even in conditions that involve higher costs and discount rates, new more restrictive minimum energy performance standards allow capturing significant benefits for the society as a whole and for consumers individually. Reviewing the minimum energy performance standards is a critical and urgent issue for Brazil and the methodology presented in this paper can be useful in the process of decision-making related to new regulatory developments. • More restrictive MEPS for air conditioners is urgently needed in Brazil. • The synergy between the CGIEE, Procel and PBE/INMETRO should be improved. • The methodology presented in the paper can support the process of MEPS revisions. • Energy, economic and environmental benefits of more stringent MEPS can be very significant. [ABSTRACT FROM AUTHOR]

• Observation of spray of biodiesel is done to correlate with engine performance. • Mass of fuel molecules of B100 are found to be heavier than B0 and B50. • Mass of fuel molecules of B50 and B0 are found to be similar. • Satuer mean diameters of fuel molecules of B50 and B100 are larger than diesel. • Penetration lengths of vapour of B50 and B100 are 6.28% and 13.75% longer. • Combustion duration B0, B50 and B100 are 52°CA, 57°CA and 59°CA, respectively. Palm oil diesel (POD) is derived from palm oil using an esterification process. POD has similar physicochemical properties to fossil diesel, and this allows POD to be the primary substitute to diesel. However, existing research has found that the combustion of POD in CI engines produce lower performance standards than pure diesel. This is due to POD having a higher viscosity, density and presence of heavier molecules resulting in poor evaporation and mixing with the air leading to higher brake specific fuel consumption (BSFC) and reduced power. This research aims to observe the fuel spray behaviors inside the combustion chamber and corelate these with the lower performance of POD than diesel. POD is tested at 100% (B100) and, blended with diesel at a ratio of 50/50 (B50) by volume to reduce the viscosity. The study of spray properties in real engines is expensive and difficult, with most studies being performed in constant volume transparent chambers using Mie-scattering and Schlieren imaging techniques. Therefore, the engine simulation is conducted using ANSYS Forte software to observe the in-cylinder spray behaviors. A 26-kW diesel engine used in a generator is modelled using SolidWorks with respective performance parameters noted from simulation data. The CHEMKIN-PRO software is used to create POD by solving thousands of reaction combinations. Spray analysis of fuels shows longer penetration lengths with POD, higher Sauter Mean Diameter (SMD) and heavier mass of fuel molecules than diesel. These along with a lower calorific value of POD resulted in lower power and a higher brake specific fuel consumption than diesel. Furthermore, B50 performs better than B100. [ABSTRACT FROM AUTHOR]