Energy Efficiency Characteristics Research Articles

Energy efficiency and thermal comfort characteristics of convection–radiation combined cooling system in office buildings

Energy efficiency and thermal comfort characteristics of convection–radiation combined cooling system in office buildings

Advancing the Decarbonization of the Construction Sector: Lifecycle Quality and Performance Assurance of Nearly Zero-Energy Buildings

Dealing with and maintaining high-quality standards in the design and construction phases is challenging, especially for on-site construction. Issues like improper implementation of building components and poor communication can widen the gap between design specifications and actual conditions. To prevent this, particularly for energy-efficient buildings, it is vital to develop resilient, sustainable strategies. These should optimize resource use, minimize environmental impact, and enhance livability, contributing to carbon neutrality by 2050 and climate change mitigation. Traditional post-occupancy evaluations, which identify defects after construction, are impractical for addressing energy performance gaps. A new, real-time inspection approach is necessary throughout the construction process. This paper suggests an innovative guideline for prefabricated buildings, emphasizing digital ‘self-instruction’ and ‘self-inspection’. These procedures ensure activities impacting quality adhere to specific instructions, drawings, and 3D models, incorporating the relevant acceptance criteria to verify completion. This methodology, promoting alignment with planned energy-efficient features, is supported by BIM-based software and Augmented Reality (AR) tools, embodying Industry 4.0 principles. BIM (Building Information Modeling) and AR bridge the gap between virtual design and actual construction, improving stakeholder communication and enabling real-time monitoring and adjustments. This integration fosters accuracy and efficiency, which are key for energy-efficient and nearly zero-energy buildings, marking a shift towards a more precise, collaborative, and environmentally sensible construction industry.

Intelligent multi-agent model for energy-efficient communication in wireless sensor networks

The research addresses energy consumption, latency, and network reliability challenges in wireless sensor network communication, especially in military security applications. A multi-agent context-aware model employing the belief-desire-intention (BDI) reasoning mechanism is proposed. This model utilizes a semantic knowledge-based intelligent reasoning network to monitor suspicious activities within a prohibited zone, generating alerts. Additionally, a BDI intelligent multi-level data transmission routing algorithm is proposed to optimize energy consumption constraints and enhance energy-awareness among nodes. The energy optimization analysis involves the Energy Percent Dataset, showcasing the efficiency of four wireless sensor network techniques (E-FEERP, GTEB, HHO-UCRA, EEIMWSN) in maintaining high energy levels. E-FEERP consistently exhibits superior energy efficiency (93 to 98%), emphasizing its effectiveness. The Energy Consumption Dataset provides insights into the joule measurements of energy consumption for each technique, highlighting their diverse energy efficiency characteristics. Latency measurements are presented for four techniques within a fixed transmission range of 5000 m. E-FEERP demonstrates latency ranging from 3.0 to 4.0 s, while multi-hop latency values range from 2.7 to 2.9 s. These values provide valuable insights into the performance characteristics of each technique under specified conditions. The Packet Delivery Ratio (PDR) dataset reveals the consistent performance of the techniques in maintaining successful packet delivery within the specified transmission range. E-FEERP achieves PDR values between 89.5 and 92.3%, demonstrating its reliability. The Packet Received Data further illustrates the efficiency of each technique in receiving transmitted packets. Moreover the network lifetime results show E-FEERP consistently improving from 2550 s to round 925. GTEB and HHO-UCRA exhibit fluctuations around 3100 and 3600 s, indicating variable performance. In contrast, EEIMWSN consistently improves from round 1250 to 4500 s.

D2D Self Organization in IOT via Triple Modular Redundancy Based MDS Code

Device-to-Device (D2D) communication is a key enabling technology to replace base station-to-device(B2D) communication. D2D with IoT realization has spectral and energy-efficient features for on-time quality data transfer. However, the rapid growth of such networks and the dynamic quality of service demands of user equipment require robust and efficient service quality in disasters, outages, and adversarial conditions. To address this challenge, this paper proposes a triple modular redundancy based on the maximum distance separable (TMR-MDS) technique has been proposed, which modifies the repair bandwidth by utilizing more storage occupation and improving the D2D link availability in the system. The proposed TMR-MDS technique will be used, which is composed of two phases: trust management modules and triple modular redundancy storage modules. As part of the initial stage of trust management, a fuzzy logic model is employed to determine the user’s trust value after the user’s behaviour is examined. Second, using the majority voting scheme to improve triple modular redundancy storage. Furthermore, if any problem occurs in the node, then it will self-organize. MATLAB is used to evaluate the performance of the proposed system. The overall system performance is evaluated in terms of the network’s trust level, and the communication cost of the proposed strategy. As per the experimental results, the proposed TMR-MDS method has a better performance of 12.67%, 23.68%, and 25.87% than hierarchical bi-partite, double replication MDS, and unequal repairing locality code.

Energy efficiency considerations in software‐defined wireless body area networks

AbstractWireless body area networks (WBAN) provide remote services for patient monitoring which allows healthcare practitioners to diagnose, monitor, and prescribe them without their physical presence. To address the shortcomings of WBAN, software‐defined networking (SDN) is regarded as an effective approach in this prototype. However, integrating SDN into WBAN presents several challenges in terms of safe data exchange, architectural framework, and resource efficiency. Because energy expenses account for a considerable portion of network expenditures, energy efficiency has to turn out to be a crucial design criterion for modern networking methods. However, creating energy‐efficient systems is difficult because they must balance energy efficiency with network performance. In this article, the energy efficiency features are discussed that can widely be used in the software‐defined wireless body area network (SDWBAN). A comprehensive survey has been carried out for various modern energy efficiency models based on routing algorithms, optimization models, secure data delivery, and traffic management. A comparative assessment of all the models has also been carried out for various parameters. Furthermore, we explore important concerns and future work in SDWBAN energy efficiency.

Numerical Investigation of Cyclone Separators: Physical Mechanisms and Theoretical Algorithms

AbstractGas‐particle aero‐type cyclones have revolutionized biochemical processes, engineering industries, and environmental pollution protection by effectively separating particles from gas. These devices rely on gravitational energy and centrifugal force to dissipate particle phase energy, but achieving optimal energy efficiency while minimizing pressure drop remains challenging. This has led to the development of various cyclone designs in commercial industries, each with unique energy efficiency characteristics. The intricate gas‐particle flow inside cyclones is a critical issue impacted by cyclone geometry, operating conditions, and media parameters. Advanced numerical simulations have been employed to understand this complex flow pattern better, offering researchers valuable insights into the mechanisms of different cyclone separators. This comprehensive review explores the available numerical methods in the literature on cyclones and their corresponding validations. Computational numerical modeling is a promising technique for predicting cyclone energy efficiency, gas‐particle behavior, and overall performance. This investigation delves into the progress and numerical forms of gas‐particle flow cyclones, examining how different parameters impact cyclone performance and flow patterns within the two‐phase flow. The future developments and challenges that may further promote the development of aero‐type cyclone separators, providing theory and engineering support for future cyclone designs, are also covered. As a result, it can confidently be reported that aero‐type cyclone separators remain a critical component in various industrial sectors, offering energy‐efficient solutions for mitigating environmental pollutants and gas‐particle separation systems. With continued development and research, these devices will undoubtedly shape the future of energy processes and engineering industries, ushering in a new era of sustainability and efficiency.

Research on the energy efficiency improvement of closed loop wastewater source heat pump with direct-expansion heat exchanger

The closed-loop wastewater source heat exchanger (WSHE) has advantages such as being non-clogging and resistant to corrosion, but their heat transfer efficiency is relatively low, therefore it is still not the mainstream form of heat exchanger of wastewater source heat pump (WSHP). A novel CO2 direct-expansion wastewater source heat exchanger (DX-WSHE) is proposed in this paper, aiming to significantly improve the heat transfer rate of the heat exchanger and the energy efficiency of the heat pump system. The direct-expansion heat transfer process is complex, large grid number and long calculation time will be required if calculated by conventional numerical simulation software. Therefore, a three-dimensional transient heat transfer model was developed based on the thermal resistance and capacity model, which offers the advantages of fast computation speed and strong flexibility. The heat transfer and energy efficiency characteristics under different parameters were studied. The coefficient of performance (COP) of the direct-expansion wastewater source heat pump (DX-WSHP) can be increased by 31.0% compared to conventional design, and the heat flux of the direct-expansion wastewater source heat exchanger can be up to 250 W/m for the standard group. Compared with conventional designs, the direct-expansion wastewater source heat pump has excellent heat transfer and energy efficiency capabilities, which is a promising building energy saving and emission reduction technology.

Optimization of power allocation for the multi-stack PEMEC system considering energy efficiency and degradation

With the large-scale application of the proton exchange membrane electrolysis cell (PEMEC), the power allocation of the multi-stack PEMEC system has attracted ever-growing attention. However, fluctuating power significantly affects the lifetime and energy efficiency of the system. In this work, a power allocation strategy of the system is proposed based on detailed modeling and characteristics analysis. A complete model of PEMEC is developed considering bubble coverage for research of operating characteristics. To analyze the energy efficiency characteristics of the system, a power model of the PEMEC stack is established. A mathematical method to real-time obtain the frontier of optimal energy efficiency of stacks is also proposed. The degradation model of the proton exchange membrane is developed to determine the safe operation boundary. And then considering the operating status, voltage degradation is introduced to characterize the degradation of PEMEC dynamically. Finally, a power allocation strategy is proposed considering the system's energy efficiency and degradation. Furthermore, a composite revenue function is presented to compare the performance of different power allocation strategies. The results show that the system has the highest consolidated revenue under the proposed strategy. Current work is conducive to the popularization and generalization of the multi-stack PEMEC system.

Research on Energy Efficiency Characteristics of Mining Shovel Hoisting and Slewing System Driven by Hydraulic-Electric Hybrid System

Mining shovel is a crucial piece of equipment for high-efficiency production in open-pit mining and stands as one of the largest energy consumption sources in mining. However, substantial energy waste occurs during the descent of the hoisting system or the deceleration of the slewing platform. To reduce the energy loss, an innovative hydraulic-electric hybrid drive system is proposed, in which a hydraulic pump/motor connected with an accumulator is added to assist the electric motor to drive the hoisting system or slewing platform, recycling kinetic and potential energy. The utilization of the kinetic and potential energy reduces the energy loss and installed power of the mining shovel. Meanwhile, the reliability of the mining shovel pure electric drive system also can be increased. In this paper, the hydraulic-electric hybrid driving principle is introduced, a small-scale testbed is set up to verify the feasibility of the system, and a co-simulation model of the proposed system is established to clarify the system operation and energy characteristics. The test and simulation results show that, by adopting the proposed system, compared with the traditional purely electric driving system, the peak power and energy consumption of the hoisting electric motor are reduced by 36.7% and 29.7%, respectively. Similarly, the slewing electric motor experiences a significant decrease in peak power by 86.9% and a reduction in energy consumption by 59.4%. The proposed system expands the application area of the hydraulic electric hybrid drive system and provides a reference for its application in oversized and super heavy equipment.

How the single-family residence housing market capitalizes green property upgraded features: evidence from city of Austin

Purpose By comparing regression models, this study aims to analyze the added home value of green sustainability features and green efficiency characteristics, rather than green certifications, in the city of Austin. Design/methodology/approach The adoption of home green energy efficiency upgrades has emerged as a new trend in the real estate industry, offering several benefits to builders and home buyers. These include tax reductions, health improvements and energy savings. Previous studies have shown that energy-certified single-family homes command a premium in the marketplace. However, the literature is limited in its analysis of the effects of green upgrades and certification on different types of single-family homes. To address this gap, this research collected data from 21,292 multiple listing services (MLS) closed home-selling listings in Austin, Texas, over a period of 35 months. Findings The analysis results showed that green efficiency features could generally increase single-family housing prices by 11.9%, whereas green sustainability upgrades can potentially bring a 11.7% higher selling price. Although green housing certification did not have significant effects on most housing groups, it did increase closing prices by 13.2% for single-family residences sold at the medium price range, which is higher than the impacts from simply listing the green features on MLS. Originality/value The study contributes to the body of knowledge by examining the market value of broadly defined energy efficiency and sustainability features in the residential housing market. The findings can help policymakers, brokerage firms, home builders and owners adjust their policies and strategies related to single-family home sales and mortgage approvals. The research also highlights the potential benefits of capitalizing on green housing features other than certifications.

COVID-19 lockdown energy use changes in Australian apartments

The emergence of low-carbon and net zero houses and developments with innovative energy and water efficiency features are a driver of change in the built environment sector around the world. Innovation has occurred through design guidelines and standards but the key to the building's performance is the occupancy routines and practices. The routines and practices of individuals are highly dependent however on institutional and social rhythms outside of the built form. These rhythms relate to the working and social lifestyle of people that influence when homes are occupied and traditionally when energy is consumed. Building on previous analyses conducted around the world on residential energy consumption changes during COVID-19, this research analyzed the impacts of COVID-19 restrictions on energy use in an Australian case study. Three individual apartment buildings in a sustainable precinct with solar panels and battery systems are assessed via qualitative and quantitative data collection before and during COVID-19 lockdowns. Each building's total energy consumption is analyzed for the two periods through machine learning algorithms and further analysis highlighted the changes in weekday energy use. Three individual apartments are further investigated, supplemented with qualitative data collection, to understand the changes to and drivers of energy practices. The results showcase how the COVID-19 lockdown measures influenced the energy practices and time of use in each building and apartment. They also outline a discrepancy between self-reported energy practices and the actual timing of energy use.

Application of sustainable architecture principles in buildings of innovative research and production facilities

In the era of information society, science and technology keep developing at rapid pace along with a growing number of innovative R&D facilities, whose role in society is increasing and their typology becoming more complex. The study considers architectural and planning solutions for buildings involved in different innovative activities. A review of such implemented projects across Russia and other countries revealed their urban planning significance and their distinctive architectural, planning, spatial, functional and energy-efficiency features as examples of application of sustainable architecture principles.

Low-Voltage Haze Tuning with Cellulose-Network Liquid Crystal Gels.

Being key components of the building envelope, glazing products with tunable optical properties are in great demand because of their potential for boosting energy efficiency and privacy features while enabling the main function of allowing natural light indoors. However, windows and skylights with electric switching of haze and transparency are rare and often require high voltages or electric currents, as well as not fully meet the stringent technical requirements for glazing applications. Here, by introducing a predesigned gel material we describe an approach dubbed "Haze-Switch" that involves low-voltage tuning of the haze coefficient in a broad range of 2-90% while maintaining high visible-range optical transmittance. The approach is based on a nanocellulose fiber gel network infiltrated by a nematic liquid crystal, which can be switched between polydomain and monodomain spatial patterns of optical axis via a dielectric coupling between the nematic domains and the applied external electric field. By utilizing a nanocellulose network of nanofibers ∼10 nm in diameter we achieve <10 V dielectric switching and <2% haze in the clear state, as needed for applications in window products. We characterize physical properties relevant to window and smart glass technologies, like the color rendering index, haze coefficient, and switching times, demonstrating that our material and envisaged products can meet the stringent requirements of the glass industry, including applications such as privacy windows, skylights, sunroofs, and daylighting.

From existing conventional building towards LEED certified green building: case study in Bangladesh

Green Building refers to the planning, design, construction, and operation of buildings considering indoor environment quality, occupant health, using energy, water, and other resources more efficiently; and reducing waste, pollution, and the overall environmental impact. Among the Green Building guidelines, Leadership in Energy and Environmental Design (LEED) offers a certification and rating system by which buildings are certified in different categories. The LEED rating system is used to rate an existing building how much it is fulfilling the criteria of Green Building (GB) or not. This research explored how an existing conventional building can be retrofitted to satisfy green building standards. An academic building of KUET has been selected for the study. A field survey and Participatory Rural Appraisal (PRA) tools (i.e., Focus Group Discussion (FGD), Key Informant Interview (KII)) were used for the data collection and then the data was analyzed by comparative analysis concerning the LEED 2009 rating system for assessing the building. The New Academic building receives 31 points out of 110 and so cannot earn any certification level. The lacking for which the points were not gained is identified and the installation of water and energy efficiency features, rooftop gardening is suggested as retrofitting options to earn the green building certification level.

Time-dependent electric bus and charging station deployment problem

Battery electric buses (BEBs) have gained popularity due to their emission-free and energy-efficient features. Many transit authorities worldwide have set goals to gradually replace their bus fleets with BEBs. Considering the potential decline in BEB battery and charger prices, this study proposes a time-dependent bus fleet transition model to determine the optimal bus fleet transition plan, which includes selecting the bus lines to be electrified, determining the timing and type of BEBs to be purchased, and deploying on-route fast chargers and depot chargers. The model is a bi-objective integer linear program that considers the trade-off between electrified transit mileages and bus electrification costs. A normalized normal constraint method is applied to solve the bi-objective optimization model. The effectiveness of the proposed model is tested using a real-world bus network. Additionally, sensitivity analyses are conducted to better understand the impact of different parameter values on the optimal solutions. Our proposed model can provide transit authorities with a powerful tool to make informed decisions about their BEB fleet replacement plans.

Modeling of Hybrid Henry Gas Solubility Optimization Algorithm with Deep Learning-Based LED Driver System

Light emitting diodes (LEDs) have become an effective lighting solution because of the characteristics of energy efficiency, flexible controllability and extended lifetime. They find use in numerous lighting systems for residents, industries, enterprises and street lighting applications. The efficiency and trustworthiness of the LED systems considerably based on the thermal mechanical loading improved several degradation schemes and respective interfaces. The complication of the LED systems limits the theoretic interpretation of the core reasons for the luminous variation or the formation of the direct correlation among the thermal aging loading and the luminous output. Therefore, this paper designs a new hybrid Henry gas solubility optimization with deep learning (HHGSO-DL) algorithm for LED driver system design. The presented HHGSO-DL technique mainly concentrates on the derivation of empirical relationships among the design parameters, thermal aging loading and luminous outcomes of the LED product. In the presented HHGSO-DL technique, bidirectional long short-term memory (BiLSTM) algorithm is executed for examining the empirical relationship and its hyperparameters can be tuned by the HHGSO algorithm. In this work, the HHGSO algorithm is derived by the integration of traditional HGSO algorithm with oppositional-based learning (OBL) concept. The performance of the HHGSO-DL technique can be investigated on LED chip packaging and LED luminaire with thermal aging loading. The extensive results demonstrate the promising performance of the HHGSO-DL technique over other state-of-the-art approaches.

Energy efficiency features of vernacular house in Bosnia and Herzegovina: A case study of Svrzo’s house complex

This paper analyzed sustainable principles of vernacular architecture in Bosnia and Herzegovina featured in the Svrzo’s house complex in Sarajevo, which can serve as an example that can be utilized in contemporary architecture. An energy-efficiency analysis was performed by using DesignBuilder software. The aim was to investigate whether the building design, building’s envelope materialization, and spatial organization comply with today’s energy-efficiency standards and if such principles can be applied in contemporary design. The calculation of the energy demands for heating and cooling showed that the division of the house in winter and summer quarters is an energy-efficient approach that could be transposed into contemporary architecture. The calculations also showed that the materialization of the building envelope of the winter quarter is not energy efficient enough to be used in modern constructions, but the positive aspects of the building envelope materialization such as the use of natural, local materials with good heat capacity are important elements which could serve as guidelines for the materialization of contemporary buildings. Therefore, a new materialization was proposed on the basis of these principles. The calculations showed that the analyzed winter quarter became energy-efficient while maintaining sustainable principles borrowed from vernacular architecture.

Energy Efficient Features of Vernacular Houses in Tropical Hilly Area of Indonesia

Energy efficient building is one of the alternative solutions to overcome the rapidly increasing use of energy consumption by the building sector. Traditional or vernacular houses rarely use mechanical means to create a comfortable living environment. Thus, the electrical energy consumed by traditional or vernacular houses was relatively low. It is believed that energy efficient features can be found in vernacular houses. Thence, this study explores the energy efficient features of vernacular houses, with a case study in the hilly area of the tropics, Palu-Indonesia. Field studies were conducted. Six vernacular houses were chosen purposively as the study samples based on building orientation, building form, roof form, wall construction, and type of opening. HOBO H21 and U12-012 were utilised to measure the internal and external air temperature, relative humidity, light intensity, wind speed and wind direction. The study result indicates that the sample houses’ thermal condition was slightly better than the external thermal condition. Sample 1 can modify the external air temperature up to 42.8 K during the daytime. The light condition, in contrast, showed poor performance. Thus, more transparent material with proper shading was needed to succeed daylighting in the buildings’ interior. Several energy efficient features of vernacular houses found in the samples are as follows: shallow building plan elongated to East – West, building geometry, resistive building materials, the use of ceilings, and side-hung or jalousie type of windows with an adequate size of the effective opening for ventilation and lighting.

Escope: An Energy Efficiency Simulator for Internet Data Centers

Contemporary megawatt-scale data centers have emerged to meet the increasing demand for online cloud services and big data analytics. However, in such large-scale data centers, servers of different generations are installed gradually year by year, making the data center heterogeneous in computing capability and energy efficiency. Furthermore, due to different processor architectures, complex and diverse load dynamic changing, business coupling, and other reasons, operators pay great attention to processor hardware power consumption and server aggregation energy efficiency. Therefore, the simulation and analysis of the energy efficiency characteristics of data center servers under different processor architectures can help operators understand the energy efficiency characteristics of data centers and make the optimal task scheduling strategy. This is very beneficial for improving the energy efficiency of the production system and the entire data center. The Escope simulator designed in this study can simulate the online quantity (placement strategy) of different types of servers in the data center and the optimal operating range of the servers. The purpose of this is to analyze the energy efficiency characteristics of all servers in the data center and provide data center operators with the energy efficiency and energy proportionality characteristics of different servers, improve server utilization, and perform reasonable scheduling. Through the simulation experiment of Escope, it can be proved that running the server at the highest energy efficiency point or running the server under full load cannot improve the energy efficiency of the entire data center. The simulation algorithm provided by Escope can select the optimal set of servers and their corresponding utilization. Escope can set up a variety of simulation strategies, and data center operators can simulate data center energy efficiency according to their own needs. Escope can also calculate the power cost savings of introducing new servers in the data center, which provides an essential reference for operators to purchase servers and design data centers.

Review and comparison of methods for limiting leakage currents in single-phase transformerless PV inverter topologies

Transformerless inverters are widely used in different photovoltaic nonisolated ac module applications, mainly in grid-tied photovoltaic (PV) generation systems, due to the benefits of achieving high efficiency over a wide load range, and low cost. Various transformerless inverter topologies have been proposed to meet the safety requirement of low ground leakage currents, such as specified in the VDE-4105 standard and low-output ac-current distortion. Topology modifications of transformerless full bridge inverters are designed to balance and maintain a constant common mode output voltage, thereby eliminating or reducing leakage currents. This article reviews and compares the different methods for limiting leakage currents in known topologies of the full-bridge transformerless inverters, such as: H4, H5, H6, HERIC, and their improvements. The main topologies and strategies used to reduce the leakage current in transformerless schemes are summarized, highlighting advantages and disadvantages and establishing points of comparison with similar topologies. To compare the properties of different medium to high power inverters, PV inverter topologies were implemented using IGBTs and tested with the same components, same simulation parameters in PSPICE to evaluate their performance in terms of energy efficiency and leakage current characteristics. The detailed power stage operating principles, extended PWM modulator, and integrated universal gate driver with galvanic isolation in the transmission path of control signal for all IGBTs of the inverter, as well isolated and floating bias power supply for gate drivers are described.