Saving Energy Consumption Research Articles

Energy Performance Aspects of Residential Buildings in Latvia

Abstract Measures on increasing energy efficiency is a way for ensuring sustainable energy supply, reducing emission of gases causing the greenhouse effect, improving safety of energy supply, decreasing dependence on import of energy and promoting the EU competitiveness. Improvement of energy performance of buildings as a direction of activities is provided in national policy planning documents of major importance such as the National Energy and Climate Plan for 2021–2030 and the Strategy of Latvia for the Achievement of Climate Neutrality by 2050. Residential buildings form a considerable part of the total Latvian housing stock – 27 % according to the number of buildings and 44 % according to their area. Therefore, the increase of energy performance of residential buildings is very significant for achieving the national energy saving targets, i.e. a cumulative savings of final energy consumption of about 6 PJ by 2030. The research analyses the sector of residential buildings, their statistical data, the energy consumption and requirements of the energy performance standards. To characterise this sector more comprehensively, information has been evaluated on energy performance certificates of residential buildings issued during the period from 2016 to 2021, allowing the authors to make general conclusions on the energy performance level of residential buildings and to provide proposals for increasing their energy efficiency.

Amorphous Mixed-Vanadium-Tungsten Oxide Films as Optically Passive Ion Storage Materials for Solid-State Near-Infrared Electrochromic Devices.

Near infrared (NIR) electrochromic (EC) devices that selectively modulate the NIR light without affecting the daylight represent a promising window technology for saving energy consumption of buildings. Current research efforts have been focused on developing NIR-EC materials, while little attention has been directed to the optically passive ion storage materials that are crucial for balancing charges in a full NIR-EC device. Herein, we report that amorphous phase mixed-vanadium-tungsten oxide films exhibit minimum optical change with high ion storage capacity, which enables the usage of the mixed-metal oxides as optically passive counter electrode materials for NIR-EC devices. The mixed-vanadium-tungsten oxide films are synthesized by a room-temperature solution-based photodeposition method that allows us to precisely engineer the metal compositions and thicknesses of the mixed-metal oxide films, thus optimizing their optical inertness and ion storage capability. A solid-state NIR-EC device assembled with the mixed-vanadium-tungsten oxide film as an ion storage layer and the amorphous tungsten oxide hydrate as the NIR-EC layer shows fast response speed with cycling stability up to 10,000 cycles, proving the outstanding charge balancing capability of mixed-metal oxide. Our work provides an efficient strategy for developing optically passive ion storage films with high ion storage capability for high-performance EC devices.

Optimal chiller loading by improved sparrow search algorithm for saving energy consumption

Aims to reduce the energy consumption in a heating, ventilation, and air conditioning (HVAC) system with improper load distribution. An efficient optimization method, the improved sparrow search algorithm, has been developed to address the optimal chiller loading (OCL) problem for parallel chillers system. In general, the optimization goal is to minimize the system's energy consumption subject to meeting load demands, and the partial load rate of each chiller is taken as the optimization variable. This algorithm utilizes the Circle chaotic mapping to initialize the position to improve the quality and diversity of the initial solution. Meanwhile, to improve the algorithm's optimization accuracy, the information exchange reinforcement mechanism of the Gray Wolf Optimizer is used to update the producer position. Besides, the chaotic sine cosine mechanism is combined with the scrounger position update to enhance the convergence speed of the algorithm. Eventually, three case studies are selected to evaluate the performance of ISSA in detail and compared with other optimization algorithms. Experimental simulation verified that the improved sparrow search algorithm is more energy-saving and has the advantages of fast convergence, short running time and good robustness.

Scheduling an Energy-Aware Parallel Machine System with Deteriorating and Learning Effects Considering Multiple Optimization Objectives and Stochastic Processing Time

Currently, energy conservation draws wide attention in industrial manufacturing systems. In recent years, many studies have aimed at saving energy consumption in the process of manufacturing and scheduling is regarded as an effective approach. This paper puts forwards a multi-objective stochastic parallel machine scheduling problem with the consideration of deteriorating and learning effects. In it, the real processing time of jobs is calculated by using their processing speed and normal processing time. To describe this problem in a mathematical way, a multi-objective stochastic programming model aiming at realizing makespan and energy consumption minimization is formulated. Furthermore, we develop a multi-objective multi-verse optimization combined with a stochastic simulation method to deal with it. In this approach, the multi-verse optimization is adopted to find favorable solutions from the huge solution domain, while the stochastic simulation method is employed to assess them. By conducting comparison experiments on test problems, it can be verified that the developed approach has better performance in coping with the considered problem, compared to two classic multi-objective evolutionary algorithms.

SILOS: An Intelligent Fault Detection Scheme for Solar Insecticidal Lamp IoT With Improved Energy Efficiency

Solar Insecticidal Lamp Internet of Things (SIL-IoT) nodes are susceptible to failures due to the harsh environment, burn-in, theft, and vandalism in the agricultural setting. Most state-of-the-art research mainly focuses on fault detection without considering hardware and communication performance in terms of potential fault modes, energy consumption, and network loads. This study presents a completely decentralized solution, namely a SIL-oriented binary sliding window-based fault self-detection scheme (SILOS), which can be performed on each SIL-IoT node. The problem we are trying to answer is how to detect faults as accurately as possible while keeping the communication overhead, memory, and computational costs low. Specifically, we develop a fault dictionary concept to 1) model the faults of SIL-IoT nodes; 2) construct the fault dictionary according to the characteristics of measurements; and 3) detect faults via the fault dictionary. In addition, a binary-based sliding window (BSW) fault self-detection approach is proposed to save detection costs and reduce the false alarm rate (with only 92 B system caches). A series of experiments are performed to evaluate the performance of the proposed method. The result demonstrates that the BSW method can detect faults with an average accuracy of 99.14% with less than 1% energy consumption. By only sending the fault code, 71-B data (i.e., data transmitting and forwarding) can be reduced, saving energy consumption, and decreasing network congestion.

Room-temperature tandem conversion of cyclic alkenes into 1,2-diols using molecular oxygen and β-MnO2 heterogeneous catalyst

Tandem conversion of cyclohexene into 1,2-cycloheanediol was attained by applying the generated by-product carboxylic acid as catalyst 2, realizing the effective utilization of isobutyric acid, shortening reaction time, and saving energy consumption.

Analysis on the Influence Factors of Heat Dissipation of Undersea Data Center Based on Multiple Linear Regression

Deploying data centers in the waters near coastal cities can greatly reduce the distance between data and users, not only eliminating the need to occupy land resources, but also saving energy consumption, which is a completely green and sustainable data center solution. Under the background of resource conservation and green development, this paper puts forward the project of undersea data center heat dissipation. Through the establishment of multiple linear regression model, the influence of tidal and seasonal changes on the heat dissipation of undersea data center is analyzed. Finally, it is concluded that the seasonal changes have the greatest impact on the heat dissipation of the undersea data center container. In the future, the placement strategy of data center and the methods to improve the heat dissipation efficiency will be further discussed.

Research on energy conservation in the hotel industry under Macau’s dependence on external energy

The Macau Special Administrative Region has a special urban form. It is located on the coast of the Pearl River Delta, with a land area of only 33.6 square kilometers. The population living here is close to 700,000. It is the region with the highest population density in the world, and its energy mainly depends on imports. With the new coronavirus epidemic, Macau’s tourism industry has been hit hard, and energy expenditures have risen with changes in the international situation. As an important economic support industry in Macau, the energy conservation development of the hotel industry is extremely important. Since 2007, Macau has launched “The Macau Energy Conservation Week, in conjunction with many departments and tourism companies in Macau, and the establishment of the Macau Green Hotel Award in the same year, have had a profound impact on Macau’s energy consumption savings and improved the efficiency of Macau’s hotel industry in terms of energy use. In pursuit of the goal of carbon peaking, the hotel industry in Macau has generally passed the ISO 50001:2018 Energy Management System (EnMS) certification, and most hotels have exceeded the Energy Use Intensity standard assessed by the Cornell Hotel Sustainability Benchmarking Index. Under the concept of green energy and other concepts, the hotel industry in Macau has now begun to use renewable energy for hotel use. Top hotels in Macau decreased by an average of 23.6% in 2021. After the return of Macau’s sovereignty, Macau’s unique political attributes and urban characteristics have different standards for the energy use of the entire industry and the characteristics of laws and regulations, which make it have different standards from mainland China. Based on preliminary research on the energy saving and environmental protection of the hotel industry in Macau, this research collects statistics on the energy saving data of the hotel industry and finally proposes improvements based on the energy utilization and environmental protection of the Macau Special Administrative Region and similar coastal peninsula cities.

A Hybrid Accuracy- and Energy-Aware Human Activity Recognition Model in IoT Environment

Personalised health and fitness provide users with information regarding their wellbeing and an opportunity to inform healthcare services for better patient outcomes. Underpinning this industry sector is the need to establish human activity recognition (HAR) in a ubiquitous manner. For example, through the use of smartwatches and/or mobile phones gathering information such as heart rates, movement, and steps of a user. The engineering challenge is providing accurate, informative, and timely data without rapidly depleting the mobile device's battery life. This problem is compounded as a number of algorithms used to process such data require substantial, cloud-based resources, to achieve higher accuracy. Therefore, a balance is required between battery depletion, accuracy of data, and timely delivery of results through a mixture of cloud and local algorithmic execution. In this paper, we propose <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AE-HAR (Accuracy and Energy Aware-HAR)</i> model that delivers engineered solutions which approach optimal combinations in the consideration of energy consumption, accuracy, and timeliness of results. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AE-HAR</i> introduces a “light-weight” <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">machine learning</i> on-device component identifying the probabilistic accuracy of data together with energy consumption identification requirements. A heuristic is then adopted to determine if cloud-enabled calculations are required while including possible performance costs related to the analysis of networking infrastructures. Our model is validated in a real-world environment through experimentation that demonstrates accuracy in excess of 93% and energy consumption savings in excess of 94%.

Bifunctional Co3S4 Nanowires for Robust Sulfion Oxidation and Hydrogen Generation with Low Power Consumption

AbstractSulfion oxidation reaction holds great potential for replacing kinetically sluggish water oxidation to save power consumption and simultaneously purifying environmental sulfion‐rich sewage. However, it is still challenged by the insufficient mechanism understanding and questionable stability caused by sulfur passivation. Here, it is demonstrated that bifunctional Co3S4 nanowires for assembling hybrid seawater electrolyzer that combines anodic sulfion oxidation and cathodic seawater reduction with an ultra‐low power consumption of 1.185 kWh m−3 H2 under 100 mA cm−2, saving energy consumption over 70% compared to the traditional water splitting system. Unlike water is oxidized into O2 at high potentials under alkaline water splitting system, experiments combined with in situ characterizations uncover the stepwise oxidation of S2− to short‐chain polysulfides and then to value‐added product of S8. Density functional theory calculations prove that Co3S4 possesses reduced energy barriers in the rate‐determining S32− to S4− oxidation step and S8 desorption step, promoting conversion of short‐chain polysulfides and efficient desorption of S8. These findings reveal the catalytic mechanism of sulfion oxidation and inspire an economic approach toward the fabrication of bifunctional Co3S4 for achieving energy‐saving hydrogen production from seawater while rapidly disposing sulfion‐rich sewage with boosted activity and stability.

Performance and feasibility of utilizing solar powered ice storage system for space cooling applications

• This paper addresses the potential of integrating ice storage system with solar PV panels for the purpose of space cooling in residential and office buildings. • The proposed system was implemented on two case studies represented by one floor office building located in Abu Dhabi and four floor residential building located in Dubai. • The obtained results revealed that the proposed integrated system contributed to significant amount of savings in the annual electricity consumptions for the office and the residential buildings by 33 % and 38%, respectively when compared to the conventional fully electric powered cooling system. • The proposed sustainable model results in reducing the carbon dioxide emissions in the selected residential building by almost 154 tons per year. This paper addresses the potential of integrating a hybrid solar powered cooling system with ice storage for the purpose of space cooling in residential and office buildings. The proposed hybrid system was implemented on two case studies represented by one floor office building located in Abu Dhabi and four floor residential building located in Dubai with peak cooling loads of 70 kW and 366 kW, respectively. The solar powered system was investigated based on hourly solar radiation to fully capture the energy harvested from solar panels utilized to power the ice glycol chiller at different modes of operation. The annual power generated from the solar system was estimated using the monthly average solar radiations. The areas of PV panels installed on the roof of the office and residential buildings were 240 m 2 and 400 m 2 , respectively. A feasibility study was conducted to assess the system’s performance from both economic and environmental perspectives. Based on the obtained results, it was found that the proposed system contributed to a significant amount of savings in the annual energy consumptions in the office building which was estimated to be 38% less than the conventional cooling systems accompanied with 40% reduction in CO 2 emissions. For the residential building, the annual energy consumption savings were estimated to be 140,160 kWh and resulted in a tangible reduction in CO 2 emissions of almost 154 ton/year. The feasibility study showed that the payback periods of the office building and residential building are about 8.8 years and 7.8 years, respectively.

Study on the Application of Non-Plastering Technology of BM Lightweight Aggregate Interlocking Block

Benchmark (BM) lightweight aggregate interlocking block has the characteristics of energy saving, no plastering, convenient construction, etc., which can be used for internal infilled walls at all parts (240 mm thick block can also be used for external infilled walls). The U-shaped bricks are used in building ring beams, structural columns and lintel formwork. It eases the formwork construction process, saves energy consumption, shortens the construction period, and reduces the materials used, achieving the purpose of ensuring a high-quality building at minimum construction cost. Taking the practical project as an example, this paper studies the performance and characteristics of BM light aggregate interlocking block, and introduces the key construction technologies, aiming to provide relevant reference for the application of BM light aggregate interlocking block in practical projects.

Wall and roof solutions for a retail building considering cost investment and life cycle approach: A case study in Portugal

This study explored which envelope solutions in retail buildings led to cost-optimal levels considering the Energy Performance of Building Directive and Portuguese regulation. For such, energy simulations were run in BIM software based on the analysis of a case study in Portugal. Typical alternative solutions were tested against the original case study, and solutions with considerably lower U-value considering the code for commercial buildings (0,7 W/m2°K for walls and 0,5 W/m2.°K for roofs). To assess the cost-effectiveness of alternative envelope solutions, the Payback Period, the Net Present Value and the Internal Rate of Return at 15 years and 50 years were assessed. Results indicate that solutions with lower U-values are related to 2–5% savings in energy consumption and can be cost-effective at 15 and 50 years, namely vacuum insulation panels of 2.5 cm and sandwich panels of 8–12 cm. This leads to the conclusion that lowering present code U-values can be cost-effective, but it will result in additional initial costs.

Impact of air barriers application in LCA and LCC of naturally ventilated dwellings in mild climate regions

Assessing singular elements that constitute the air barrier of a building envelope is quite unfeasible in Life Cycle Assessment (LCA). The study of these solutions through this particular scope is often overlooked. Two major aspects contribute to it: the complexity of the relationships between elements and the reduced embodied impact of these materials in the overall construction or retrofitting works. This work uses LCA and Life Cycle Costing (LCC) to study the viability of applying two envelope air barrier solutions in dwellings with excessive air change rates and equipped with different heating systems. The application of air barrier solutions resulted in average energy consumption savings in urban terrain, almost half of those in rural terrain during the heating season. Environmental performance and life cycle costs revealed mechanically (MECH) fastened air barriers to outperform fluid (FLUID) applied ones. The median annualized cost of adopting a FLUID solution was almost four times that of a MECH solution. Dwellings equipped with electric radiators ranked first in the shortest average Energy Payback Period (EPP) and the highest average Reference Service Life (RSL) savings. With the current analysis, the adoption of MECH solutions is recommended, independently of the heating system the dwelling is equipped with.

AN ENERGY- AND DELAY-EFFICIENT TRANSMISSION MECHANISM USING REINFORCEMENT LEARNING IN WIRELESS BODY SENSOR NETWORKS

Clustering mechanism saves energy consumption and prolongs the lifetime of wireless sensor network (WSN). In this paper, we propose an energy and delay efficient transmission mechanism using reinforcement learning in wireless body sensor networks (WBSNs). In the WBSN network, in addition to the efficient energy consumption of the sensor node, when vital information is measured, additional information measured from other sensors must be transmitted to the medical staffs within a limited time so that the medical staff can make a correct decision. The proposed transmission mechanism in this paper considers two novel techniques: a novel CH selection process using reinforcement learning approach and super-frame extension to enhance energy efficiency and network lifetime. Additionally, when a vital signal is measured, it is also proposed to quickly collect relevant information and deliver it to the medical staffs so that the medical staff can make a correct decision. Because of the simulation, the proposed mechanism increased the average network lifetime by 12% and decreased the packet transmission delay by 29.4% compared to the method without reinforcement learning.

Adaptive damper control for HVAC systems based on human occupancy and indoor parameters: A development study

Occupancy-based strategies for the control of ventilation systems in buildings are effective for achieving energy savings and user comfort. Savings in energy consumption of more than 50% can be achieved by controlling heat, ventilation, and air conditioning (HVAC) systems with accurate sensory and occupancy information. In this study, the flow through the damper of the variable area valve (VAV) system and the speed of the blower’s variable frequency drive (VFD) are controlled in the HVAC system, on the basis of human occupancy and indoor parameters, namely, temperature and humidity, segment-wise in the building. In the proposed model, the flapper angle of the VAV is estimated using the indoor temperature, external temperature, and number of occupants. The occupancy data are fed to the controller proposed to regulate the flow through the ducts of the system, which is based on the flapper angle of the VAV, in order to maintain human comfort. The proposed scheme makes it possible to detect abnormalities in energy utilization and to trace maximum utilization in the building based on occupancy, with the control parameters of the HVAC adjusted for a comfortable indoor environment. Performance evaluation of the VAV system with its proposed control strategy, temperature, and flow distribution is simulated using Fluent software. A laboratory grade prototype incorporating the proposed control strategy is then developed, tested under three different conditions, and the results are reported. The experimental results show that an energy saving of 18% can be achieved.

Mixed Ionic Liquids as Entrainers for Aromatic Extraction Processes: Energy, Economic, and Environmental Evaluations

Experimental measurements for the vapor–liquid equilibria (VLE) of benzene + 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]), benzene + 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO4]), and benzene + mixed ionic liquids (ILs) (equimolar [EMIM][NTf2] + [EMIM][EtSO4] mixture) are performed. The non-random two liquid (NRTL) model binary interaction parameters are then obtained by fitting the new VLE data and the liquid–liquid equilibrium data previously reported. The interactions between chemical species are analyzed using quantum chemical calculations and the COSMO-SAC method, and it is found that the interactions between benzene and ILs are strongly attractive. Taking as a reference the industrial process that uses sulfolane as the entrainer, several novel industrial processes are proposed, which involve either pure ionic liquids [EMIM][NTf2] and [EMIM][EtSO4] or their mixtures as the extractant for separating aromatic hydrocarbons (benzene) and paraffins (n-hexane). The optimal operating parameters, such as the number of theoretical stages, the extractant-to-hydrocarbon feed ratio, the reflux ratio, and the feed stage, are determined for the different processes. Steady-state process simulations are performed to evaluate the total annual cost (TAC) and the environmental impact (carbon dioxide emissions). It is shown that significant savings in energy consumption (reduction of 19.6–48.7%), TAC (reduction of 6.3–27.1%), and CO2 emissions (reduction of 17.8–47.6%) can be achieved for the processes that use IL extractants, compared to the process based on sulfolane extractant. The proposed IL extractant and the corresponding process are promising alternatives to conventional solvents and processes for aromatic extraction.

ПОРІВНЯЛЬНА ХАРАКТЕРИСТИКА ТЕХНОЛОГІЙ УЛАШТУВАННЯ ШАРІВ ЖОРСТКОГО ДОРОЖНЬОГО ОДЯГУ ІЗ СУМІШЕЙ ЦЕМЕНТОБЕТОННИХ УКОЧУВАНИХ ДОРОЖНІХ І ТРАДИЦІЙНИХ СУМІШЕЙ ЦЕМЕНТОБЕТОННИХ ДОРОЖНІХ

Introduction. Paving roller-compacted concrete is a multi-component, artificially obtained stone-like material that is obtained from a paving roller-compacted concrete mixture, which is characterized by increased requirements for tensile strength at bending, waterproofing, water absorption, abrasion and frost resistance. Applying the technology of arrangement of pavement layers from paving roller-compacted concrete, allows to achieve significant savings in energy consumption when using machines and equipment, to ensure less shrinkage of concrete during curing due to low water-cement ratio. Problem statement. To compare the characteristics and arrangement of traditional cement concrete and paving roller-compacted concrete, to find out whether roller-compacted concrete is an alternative to traditional concrete. Since Ukraine currently lacks, with the exception of certain areas, practical experience in the construction and maintenance of roads with a surface of rolled-compacted concrete, to establish its advantages and disadvantages. Purpose. Perform an analysis of the technology of arrangement of roller-compacted concrete. Compare the physical and mechanical characteristics of roller-compacted concrete and traditional cement concrete. Materials and methods. In the work, the analysis of domestic and foreign sources by topic was carried out, laboratory research was carried out. An experimental study of paving roller-compacted concrete was performed, literary sources of Ukrainian and foreign origins were analyzed. Results. The physical and mechanical characteristics of hardened cement concrete were determined and compared with traditional cement concrete.

Superstructure based optimization of reverse osmosis desalination systems fed by decarbonated high-pH seawater under boron restrictions

This paper presents a superstructure based optimization of reverse osmosis (RO) system fed by decarbonated seawater (DS) at high pH value under boron restrictions. Each RO stage/pass could be operated with high boron rejection. The permeate split (PS) design allows permeates with different quality collecting from both sides of pressure vessel (PV). The pH variations are fitted by experiment and simulated results from the literature. The accuracy of the RO model is also validated. Results showed that about 3.48%−18.31% water cost and 3.04%−14.61% energy consumption savings are achieved by permeate split with decarbonated seawater (PSDS) design. Water cost is less influenced by pH values for PSDS design, which might be a robust solution for pH control. A two-stage stochastic model is performed to obtain robust and flexible designs considering uncertainties of the RO design problem. Both operational conditions and process flow are adjusted to save water cost and energy consumption.

Affordable phosphor-converted LEDs with specific light quality facilitate the tobacco seedling growth with low energy consumption in Industrial Seedling Raising.

Industrial Seedling Raising (ISR) is increasingly becoming an important part of Modern Agriculture because of its efficient utilization of land, water, and fertilizer as well as its advantages of being not easily affected by the weather. However, the high cost and high energy consumption of light sources for plant growth is limiting the popularization of ISR technology. Phosphor-converted light-emitting diodes (pc-LEDs) make use of relatively affordable red phosphor and blue light chips, providing an adjustable spectrum to optimize plant growth. To identify the energy-saving light quality of pc-LEDs, we investigated the effects of a variety of light qualities on the growth of tobacco seedlings. Y3Al5O12:Ce3+, CaAlSiN3:Eu2+, KAl11O17:Eu2+ phosphors were combined with the blue light chip according to different proportions to produce the following light sources: CK (white light), T1 (blue light), T2 (red light), T3 (red: blue light ratio=1:4), T4 (red: blue light ratio=4:1). The tobacco variety Xiangyan7 grown continuously under T1, T2, T3, and T4 significantly increased the leaf area, stem length, biomass, root area and main root length compared with those grown under white light. Among the five kinds of light qualities tested, T4 treatment exerted the best effect on leaf development and biomass increase, while T2 exerted the best effect on stem elongation. The cytological analysis demonstrated that the promotion of the cell size and cell number of leaf epidermal cells by T1-T4 might contribute to the leaf expansion. Further analysis at the molecular level suggested that the light quality affected the RNA levels of the genes involved in cell division and expansion. When tobacco seedlings reached the same biomass, T1-T4 light sources saved 71%, 86%, 80% and 89% of electric energy respectively compared with white light. Therefore, the application of specific pc-LEDs not only reduces the cost of light source production, but also saves energy consumption, offering great potential for ISR technology to cut costs and increase efficiency.