Search

Wireless Multimedia Sensor Networks (WMSNs) are networks consisting of sensors that have limitations in terms of memory, computational power, bandwidth and battery life. Multimedia transmission using Wireless Sensor Network (WSN) is a difficult task because certain Quality of Service (QoS) guarantees are required. These guarantees include a large quantity of bandwidth, rigorous latency requirements, improved packet delivery and lower loss ratio. The main area of research would be to investigate the process of greedy techniques that could be modified to guarantee QoS provisioning for multimedia traffic in WSNs. This could include optimization of routing decisions, dynamic allocation of resources and effective congestion management. This study introduces a framework called Epsilon Greedy Strategy based Routing Protocol (EGS-RP) for multimedia content transmission over WSN. The framework focuses on energy efficiency and QoS by using reinforcement learning to optimize rewards. These incentives are determined by a number of variables, including node residual energy, communication energy and the effectiveness of sensor type-dependent data collection. Experimental analysis was conducted to evaluate the effectiveness of the proposed routing strategy and compare it with the performance of standard energy-aware routing algorithms. The proposed EGS-RP achieves a throughput of 217 kbps, a bandwidth of 985 bps, a packet delivery ratio of 94.45% and an energy consumption of 32%. [ABSTRACT FROM AUTHOR]

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]

The steady and controlled desalination is achievable with Hybrid-CV-CC capacitive deionization (CDI). In this paper, we assess the performance of Hybrid-CV-CC CDI by evaluating the standard performance indicators within reasonable ranges of operating and design parameters, i.e., flow rate, voltage, capacitance, cell volume, and current. However, the conflicts among performance indicators for similar operating conditions instigate the need for optimum tradeoffs. Therefore, multi-criteria optimization techniques were used for the estimation of optimum tradeoffs in the system performance. The optimized system annunciated net improvement in performance in terms of desalination (salt absorbed), energy consumption, and average salt adsorption rate up to 16%, 70%, and 117%, respectively. [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 IEEE 802.15.4 is a well-known standard that is widely utilized for wireless sensor networks in order to meet the low rate, low cost and energy efficiency requirements. Seventeen years have already passed since its appearance, but new amendments are constantly being introduced. Since the standard can operates in specific countries or can support some types of networks like SUN, LECIM and RFID, modifications are carried on the basic version and then new versions have been released. In this paper, we provide a clear and structured overview of the 802.15.4 standard and all its amendments and revisions. After a general introduction to the 802.15.4-2003 standard, we present a chronological description of the amendments specified by this standard. These descriptions include the modifications made either on the physical layer or the MAC sublayer. Some references having developed the amendments whether it be a simple overview or an evaluation of the performance of the standard have been cited. The aim of this paper is to present the evolution of the standard as well as to deal with many problems frequented by wireless sensor networks using the basic version. [ABSTRACT FROM AUTHOR]

In the next-generation heterogeneous wireless networks, designing authentication protocols that meet the demand of mobile users/applications is a challenge. This paper proposes authentication and re-authentication protocols for 4G wireless networks, in particular, LTE-Advanced (LTE-A), WLAN, and WiMAX-Advanced (WiMAX-A) interworking architecture. The proposed protocols are applicable to 5G networks. With the consideration of the existing standard authentication protocols, a new set of authentication and re-authentication protocols has been reinvented to provide fast and secure handovers (HO) in the current 4G and the next 5G networks. The proposed authentication protocols can be invoked when the users perform a vertical HO (between different networks) for the first time, whereas the re-authentication protocols can be invoked when the users perform a horizontal HO (within the same network domain). These protocols provide an efficient method to protect user identity and reduce the burden on the authentication server (AS) during the sequential handovers. The results of the analytical model show that the proposed protocols achieve better performance than standard and other protocols. The reduction of handover cost, handover delay, and energy consumption in the proposed protocols reaches up to 22%, 44%, and 17%, respectively. In addition, the verification tools show that the proposed protocols are secure, dependable, and prevent all types of authentication and secrecy attacks. [ABSTRACT FROM AUTHOR]

• Onboard eco-driving feedback improves fuel economy by 6.6% on average. • The impact of most onboard feedback tested to-date deteriorates over time. • Eco-driving feedback should include both fine- and course-grained information. • Eco-driving feedback should include performance standards. • Multimodal eco-driving feedback may be more effective than visual only. • Gamification may enhance eco-driving feedback effectiveness. • Interventions should combine eco-driving feedback with education and rewards. Eco-driving refers to suites of behavior a driver can engage in to improve fuel economy. The most common strategy used to promote eco-driving is onboard feedback that conveys information about fuel efficiency to the driver. This paper presents a statistical meta-analysis of eco-driving feedback studies in order to determine a weighted estimate of the average impact of feedback on fuel economy and explore potential moderators of its effectiveness, particularly regarding features of the feedback interface design. The main effect of onboard feedback on fuel economy across the final sample of 17 studies and 23 effect sizes was 6.6% improvement. Feedback that included information about both instantaneous and accumulated performance predicted larger effects. Though not statistically significant, trends in relationships between other feedback design features and fuel economy outcomes aligned with study hypotheses. Length of feedback intervention negatively related to effects, and pairing feedback with instructions or rewards predicted larger effects. [ABSTRACT FROM AUTHOR]

As data centers proliferate, their energy intensity deserves close attention. Always-on operations and growing usage for cloud and other backend processes make servers the fundamental driver of data center energy use. Yet servers' power draw under real-world conditions is poorly understood. This paper explores characteristics of volume servers that affect energy use, quantifying differences in power draw between higher-performing Standard Performance Evaluation Corporation (SPEC) and ENERGY STAR servers and that of a typical server. First, we establish general characteristics of the US installed base, before reporting hardware configurations from a major online retail website. We then compare idle power across three datasets (one unique to this paper) and explain their differences via the hardware characteristics to which power draw is most sensitive. We find idle server power demand to be significantly higher than benchmarks from ENERGY STAR and the industry-released SPEC database, and SPEC server configurations—and likely their power scaling—to be atypical of volume servers. Next, we examine power draw trends among high-performing servers across their load range to consider whether these trends are representative of volume servers, before inputting average idle power load values into a recent national server energy use model. Lastly, results from two surveys of IT professionals illustrate the incidence of more efficient equipment and operational practices in server rooms/closets. Future work should include server power field measurements in data centers of different sizes, accounting for variations in configurations and setting changes post-purchase, as well as investigating the linkage between time and server energy efficiency. [ABSTRACT FROM AUTHOR]

The Minimum Energy Efficiency Standards (MEES) set out minimum energy standards for rented property. Those standards are expressed in the form of an Energy Performance Certificate (EPC) rating, so securing a good EPC rating is critical, as poorly performing buildings will become unlettable. It is vital that the EPC truly refects the building's construction and services, rather than relying on inaccurate assumptions, which will often return a poorer EPC. Also, the EPC's Recommendations Report should steer away from an automatically generated list of energy efficiency measures (which may well be completely irrelevant to the building), towards a listing specific to the building and its location. Key to MEES compliance in a building with a poor EPC rating is taking the time to properly assess a number of energy improvement measures to find cost-effective improvements that deliver the required improvement in EPC rating. Careful analysis of various options can reveal that some 'easy fixes', such as upgrading lighting or an air-conditioning system, may not deliver enough of an improvement over existing installations, or they may be prohibitively costly, negating any savings overall. Exactly who pays for such energy efficiency improvements is a complex, multifaceted dilapidations question encompassing issues such as repair, statutory compliance, reinstatement/ alterations, damages / supersession and loss of rent. Depending on the circumstances, the costs associated with energy improvements are more likely to rest with the landlord -- at least currently. The situation is fluid, however, as future leases may well be drafted to include provisions relating to energy efficiency improvements. [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]

The IEEE 802.15.6 standard emerged as the most suitable standard that fits the special requirements of wireless body area networks. It provides flexibility to designers by recommending the use of several medium access control layer techniques, but does not specify how to combine some or all these recommended techniques to form the most efficient wireless body area network medium access control for a specific scenario. Our goal here is to design a wireless body area network medium access control that provides an optimal combination of these basic techniques that are available in the standard, by taking into consideration the variability and heterogeneity of the sensors. The performance of the proposed techniques is evaluated using some of the standard performance measures such as throughput, delay, and energy consumption. [ABSTRACT FROM AUTHOR]

The energy performance standards imposed on nZEB buildings require measures to reduce energy consumption. The article presents an experimental study demonstrating the reduction of energy consumption through the optimal control of the ventilation / air-conditioning systems, made in an experimental room arranged in an office building in Timisoara. To demonstrate the increased energy efficiency of the HVAC systems, while maintaining the comfort conditions in the building, four control scenarios were studied by varying the chilled water temperature at the evaporator outlet and cooling mode of the chiller condenser as well as the ventilation effects on the at night. [ABSTRACT FROM AUTHOR]

This article serves as an update to the manuscript with the same title published back in 2010. Since then, Malaysia has seen some major changes in its energy and electricity generation scene. The country is now in the 11th Malaysian Plan (11MP) and its final thrust towards the high-income status targeted by 2020. Keeping to the scope in addressing the country's energy security and sustainability through non-renewable and renewable energy (RE), this article shall update on the existing and new significant energy-related events that have taken place and how they have affected the energy landscape of the country. In addition to that, the important role of the various energy efficiency (EE) and conservation practices set in place to ensure sustainable demand growth is also highlighted. The removal of fuel subsidy by the Malaysian government in 2014, although as unpopular as it may seem, was necessary as part of its energy reform to implement a more common energy regulatory framework involving all relevant agencies to safeguard a secured and sustainable energy future is also covered here. Lastly, latest development and issues surrounding the nuclear dream that the government is currently pursuing will also be discussed. [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]

Driven by architectural trends and the need to maximize daylight, commercial building façades have become more transparent. High-performance façades include spectrally selective glazing systems, dynamic elements and insulated spandrel sections. Nevertheless, it is generally accepted that, compared to standard, traditional opaque construction, modern transparent envelopes result in increased overall energy use in these buildings. In this paper, the building façade is treated as a part of the building perimeter zone, which also includes electric lighting controls, shading attachments, HVAC components, and indoor environmental controls. Consequently, the objective is to balance the need for daylighting and view versus the need for controlling of solar gains and maintaining human comfort, while reducing energy demand for air conditioning and lighting. Key parameters in solving this problem are (1) technological advancements in glazing products, (2) utilization of dynamic building envelope components, and (3) lighting and HVAC controls. In order to demonstrate the potential of high-performance façades, a typical office building with large perimeter zones is used as an example. The basic model consists of standard brick exterior walls with 20% punched windows. Then, a comparative analysis is performed for a more transparent envelope with dynamic systems including shading and electric lighting controls, for the climates of Chicago and Rome. An integrated thermal-lighting model with flexible dynamic system controls, verified with commercial software, is expanded to simulate more complex façade controls for reducing glare problems while maximizing useful daylight. The results show the advantages of transparent façades with active systems, compared to traditional building envelopes. The more transparent building results in lower operational costs and source energy use, although total site energy use can be higher for heating-dominated climates. [ABSTRACT FROM AUTHOR]

Application of the best practice of setting minimum energy performance standards (MEPS) in technically disadvantaged countries (TDCs) faces many barriers. The best practice of determining MEPS has a comprehensive analytical framework including engineering-economic analysis, life-cycle cost-benefit analysis, as well stakeholders’ and market impact assessments. However, TDCs usually are lack of reference product classes, market data, and other necessary inputs data. This study demonstrated how to overcome those barriers to apply the best practice to TDCs using the actual experience in setting initial MEPS for Air Conditioners (ACs) in Brunei from scratch with limited secondary data as an example. The series of application works include definition of the product classes and the baseline group; collection of market data; formulation of cost-efficiency relationship from the market data; examination of the economic, environmental, and financial impacts of various MEPS options; revealing of the consumers’ willingness to pay; and analysis of the impacts and responses from the industry and consumers. The coordination with the compliance of the Montreal Protocol was also considered. The methodology should also be applicable to setting MEPF for other appliances in any TDCs. [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]

Frequency regulation (FR) is the electric grid service responsible for maintaining the system frequency at its nominal value of 60 Hz in the United States — an indicator of energy balance on the grid. In cases of mismatch between power supply and demand, FR resources either on the generation or the demand side, responding rapidly to restore system frequency to its nominal value. Due to the limited responsiveness of generators, fast and accurate demand side resources (DSR) have recently been encouraged to participate in FR. However, the tested DSRs typically require high initial equipment investment (e.g., flywheels and batteries). Large commercial buildings can provide effective load shaping with little impact to occupants’ comfort and have significant amount of available capacity for FR participation. In addition, commercial buildings are characterized by numerous interdependent HVAC subsystems and control systems. Therefore, a high-level supervisory control strategy is needed that directs the interdependent HVAC systems for FR with strengthened interactions and depressed counteractions. Simulation results suggest that large commercial buildings can provide significant FR capacity and high performance scores. Dynamic building-to-grid integration automatically and continuously provides solutions maintaining energy balance on the gird. The benefit to the power system reliability would be significant. [ABSTRACT FROM AUTHOR]

In recent studies we found that there are many optimization methods presented for multicore processor performance optimization, however each method is suffered from limitations. Hence in this paper we presented a new method which is a combination of bacterial Foraging Particle swarm Optimization with certain constraints named as Constraint based Bacterial Foraging Particle Swarm Optimization (CBFPSO) scheduling can be effectively implemented. The proposed Constraint based Bacterial Foraging Particle Swarm Optimization (CBFPSO) scheduling for multicore architecture, which updates the velocity and position by two bacterial behaviours, i.e. reproduction and elimination dispersal. The performance of CBFPSO is compared with the simulation results of GA, and the result shows that the proposed algorithm has pretty good performance on almost all types of cores compared to GA with respect to completion time and energy consumption. [ABSTRACT FROM AUTHOR]

The residential sector is the third largest electricity user in Taiwan. A clear understanding of the rapid growth in its electricity consumption is crucial to the formulation of policy. This study applied the Logarithmic Mean Divisia Index (LMDI) to a decomposition of Taiwan's residential electricity consumption based on eighteen electrical appliances. Data was obtained from questionnaire surveys conducted in 7677 households. Note that this study was conducted at various disaggregation levels in order to characterize the consumption of electricity in terms of the factors that contribute to specific end-uses. Climate was identified as the primary factor driving growth in the residential electricity consumption, accounting for an increase of 2.03 billion kWh between 2014 and 2017. In Taiwan, climatic effects manifest primarily as a substantial increase in the use of air-conditioners for cooling. Thus, efforts should be made to accelerate the replacement of low energy-efficiency air conditioners. The same methods could also be used to promote energy upgrades in existing buildings. Our analysis of specific end-uses revealed that the inefficiency of personal computers and dehumidifiers is an important factor in residential electricity consumption. Thus, minimum energy performance standards (MEPS) should be expanded to include these appliances. • This study identified factors influencing electricity consumption in the residential sector. • The electricity consumption for specific end-uses is decomposed into corresponding factors. • Contribution from climate effect is investigated by considering cooling degree days. • Four policy implications are proposed by analyzing the driving factors in depth. [ABSTRACT FROM AUTHOR]

• EU policy efforts on energy efficiency in buildings stared in the 1970s in response to the oil crisis. • The first comprehensive EU policy was the SAVE directive in 1992, introducing policy actions still relevant today. • A major step forward was the Energy Performance of Buildings Directive in 2002 and its subsequent amendments. • Mandatory energy performance standards are progressively converging towards near zero energy buildings. • Additional policies and financing are needed for the full decarbonisation of the building stock. The reduction of energy demand in buildings through the adoption of energy efficiency policy is a key pillar of the European Union (EU) climate and energy strategy. Energy efficiency first emerged in the EU energy policy agenda in the 1970s and was progressively transformed with shifting global and EU energy and climate policies and priorities. The paper offers a review of EU energy policies spanning over the last half century with a focus on policy instruments to encourage measures on energy efficiency in new and existing buildings. Starting from early policies set by the EU in response to the Oil Embargo in the 1973, the paper discusses the impact of EU policies in stimulating energy efficiency improvements in the building sector ranging from the SAVE Directive to the recently 2018 updated Energy Performance of Buildings Directive and Energy Efficiency Directive. The review explores the progress made over the last 50 years in addressing energy efficiency in buildings and highlights successes as well as remaining challenges. It discusses the impact of political priorities in reshaping how energy efficiency is addressed by EU policymakers, leading to a holistic approach to buildings, and provides insights and suggestions on how to further exploit the EU potential to save energy from buildings. [ABSTRACT FROM AUTHOR]

Tramway systems are more and more diffused today, to reduce pollution and greenhouse emissions. However, their electrical feeding substations can have significant margin for improvement. Therefore, it is questionable which kind of changes can be introduced, by changing their main features. First of all, transformer technology can be enhanced, by moving from the standard transformer to the amorphous metal one; thus, guaranteeing a significant reduction in losses. Then, by installing one dedicated storage systems for each substation. This solution can help to increase the energy efficiency; thus, recovering the tram braking energy and reducing the delivered energy from the grid, and also the reliability of the system; thus, guarantee different levels of services, in the case of failure of a feeding substation. This paper investigates in a systematic approach the two proposed solutions. In particular an amorphous metal transformer has been properly designed, and performance compared to the standard one. Then, evaluation of distributed storage installation was performed, and the aspects of reliability for these systems evaluated. Results have shown the general feasibility of the proposed solutions, showing a significant energy saving with respect to the conventional ones. [ABSTRACT FROM AUTHOR]

• Variable speed units provide cost-effective solution to improve efficiency. • Fixed speed units are not economically competitive at higher efficiency ratings. • New standard brings accumulative CO 2 reductions of 12.8% between 2019 and 2050. • Accumulative bill saving is 2620 billion RMB between 2019 and 2050. • Continuous revision of the new standard could more than double the overall impact. China is the world's largest consumer of room air conditioners, and it contributes about a quarter of global space cooling CO 2 emissions. We model the costs and benefits of recently proposed new room air conditioner minimum energy performance standards (MEPS) in China. Our results suggest that newly proposed MEPS brings accumulative CO 2 emissions reductions of 12.8% between 2019 and 2050, and accumulative bill saving of 2620 billion RMB to China's consumers. The benefits of the proposed MEPS decrease with longer MEPS revision intervals and increase with shorter intervals—indicating that the intervals should be balanced to maximize benefits while accommodating constraints due to air conditioner manufacturer design cycles. We also model potential nationwide benefits from higher MEPS. Across two increasingly aggressive MEPS scenarios, China's room air conditioner electricity consumption and CO 2 emissions in 2050 are both reduced by 15–53% compared to the proposed MEPS. The highest-efficiency scenario (reaching MEPS of annual performance factor 5.4 in 2025) provides the largest long-term national benefits. These results could inform development of a Chinese regulatory regime that effectively updates room air conditioner MEPS. Because China is the world's largest manufacturer of room air conditioners, the economic, energy, and emissions benefits resulting from higher Chinese MEPS could also have a global reach. [ABSTRACT FROM AUTHOR]

Energy efficiency can get us about half of the way to long-term climate goals. Traditional energy efficiency strategies — vehicle and appliance efficiency standards, building energy codes, utility energy efficiency programs and Energy Star — can provide about half the achievable efficiency savings (i.e., savings of about one-quarter of projected 2050 energy use). However, these strategies can benefit from a variety of improvements, and other programs and policies addressing buildings, transportation and industry can achieve substantial additional savings. These efficiency policies can be combined with strategies involving no- and low-carbon energy sources to put the United States on a trajectory toward meeting long-term energy and climate targets. [ABSTRACT FROM AUTHOR]