Improve Energy Performance Research Articles

Improving energy performance in the product design for additive manufacturing using a multi-player competition algorithm

To assess and confirm the environmental benefits of additive manufacturing (AM), it is crucial to consider environmental issues during the design stage. The energy use of AM processes can be a great contributor to the overall environmental impacts in the cradle-to-gate stage, and therefore, the assessment and improvement of the energy performance for AM during the design stage is now an emerging research task. In the literature, the energy performance is usually improved during process planning or the process chain/network design, whereas the product design for AM (DfAM) is rarely considered in the energy performance improvement so far. Therefore, the chances that would be contributed to energy performance improvement by changing product features are not fully exploited. To address this issue, we propose a framework to enable energy performance-oriented DfAM. The core of our framework is a computation procedure called a ‘multi-player competition algorithm (MPCA)’. In MPCA, the energy performance improvement in DfAM is modeled as a game of multiple players picking up design variants from a given domain with the aim of finding out the design variant leading to the highest energy performance. Based on two use cases, energy demand reduction rates of up to 3.9% and 5.8% by MPCA during the DfAM stage are observed.

Extending urban energy transitions to the mid-tier: Insights into energy efficiency from the management of HVAC maintenance in ‘mid-tier’ office buildings

Older, smaller and poorer quality commercial buildings (the ‘mid-tier’) make up much of the commercial building stock and are crucial for urban energy transitions. Action must extend beyond new commercial buildings and high-end building retrofit projects to realise deep decarbonisation of the built environment. Mid-tier buildings offer substantial opportunity for energy retrofits, though the sector lags behind premium office buildings. Comparatively, different ownership structures, tenant profiles, and facilities management regimes challenge the value-proposition for energy transition, and little is known about how to leverage energy performance improvements in this crucial sector. Focussing on the management of heating, ventilation and air-conditioning (HVAC) systems as an entry point for improvement, this paper presents empirical evidence from the largest survey conducted with Australian HVAC contractors, facility managers, and system engineers to date. The results explicate the realities of managing energy in mid-tier office buildings in Australia as a socio-technical undertaking. Our analysis identifies limits and opportunities for shaping energy efficiency of HVAC maintenance, focussed on issues pertaining to workforce, building and systems, and maintenance practices. Further, we draw out policy imperatives needed to address hurdles created by multiple market failures that complicate energy transition in mid-tier buildings.

Energy Indicators for Enabling Energy Transition in Industry

Energy transition is a fundamental process in the move towards sustainable development, but in industry, it is complicated by the remarkable sectoral heterogeneity. Fostering the realization of energy transition in the industrial sector requires the characterization of its energy dimension, in terms of energy mixes and end-uses as the determinants of transition pathways, and energy solutions and tools as the enablers of this transition paradigm. We observe that the suitability of tools for energy analysis depend on trade-offs between comprehensiveness, ease of use, robustness, and generalization ability. In this regard, we discuss the appropriateness of energy indicators and provide an overview of indicator typologies, methodological issues, and applications for energy performance evaluation and improvement. With reference to the dairy processing industry, selected as a representative industrial branch, we outline current and desirable energy benchmarking applications and exemplify the effectiveness of energy indicators in the quantification of the potential of energy solutions. The obtained results are promising and suggest that researchers should further explore the novel applications of energy indicators for energy performance improvement. To foster the establishment of energy indicators in industrial practice and energy policies, we remark that cooperation between industrial stakeholders is essential.

The impact of energy improvement measures in single-family residential buildings on air pollution in the city of Uzice

The majority of existing architecture in Serbia has poor thermal characteristics, and heating systems are mostly based on polluting energy sources. This problem results in the unsatisfactory ecological image of cities, and it is endangering the health of the population. Therefore, improving energy performance is becoming an increasingly common principle of design, within both new and existing buildings. The starting point of this paper is that the use of more than sixteen thousand individual heating systems within single-family households in Uzice is one of the most influential air pollutants in the city. The poor quality of energy sources and improper combustion processes release toxic substances into the atmosphere, but the cause of increased emissions of pollutants can be identified in the poor characteristics of thermal envelopes. This research explores whether there is a solution that reduces the pollution in single-family houses by changing the thermal envelope and heating system. The first part of the study points out the main characteristics of the Uzice agglomeration, air pollution and energy sources, while the second part describes the selected single-family housing location in the city. The final part of the research examines the impact of various energy improvement measures on the air pollution in the city of Uzice.

Post-earthquake reconstruction of residential buildings in historical centers: damage indices of structural aggregates

The post-earthquake reconstruction process of historical centers discloses several issues due to the complexity of the built heritage, typically consisting of Building Aggregates (BA). These are characterized by structures deriving from progressive volume increases that, due to partially effective connections, can interact under seismic actions. Therefore, the repair and reconstruction work after seismic event, the conservation of the architectural values and the improvement of seismic and energy performances must rely on a deeper knowledge of the BA seismic behavior and on an unitary design approach. This paper presents an analysis of the damage caused by the 2009 earthquake to the buildings of the historical centers in the Abruzzo Region, with particular interest to the BA considered as a single structural block. A new perspective of the damage on structural and non-structural components, detected by means of the AeDES form, a first level survey form for post-earthquake damage and usability assessment, is proposed. The data related to the building damage are converted into an equivalent global building damage associated to the BA using conversion metrics found in the literature. Finally, some considerations are provided to evaluate the global building damage, necessary to the development of a comprehensive damage state.

Facades-as-a-Service

Facades-as-a-Service (FaaS) is a systemic innovation model aiming to accelerate and enhance the energy and comfort performance improvement of our buildings, while safeguarding the availability of material resources for future generations. The circular economy and clean energy transitions in the built environment have respectively dominated the academic dialogue in architecture, engineering, and real estate over the last decades. While significant progress has been made, and many fine examples of more sustainable architecture exist, the process has been hindered by traditional systemic models for the planning, contracting, financing, construction, and management of building projects. If we are to meet the ambitious climate-change mitigation goals and material resource preservation challenges of our generation, it is crucial to re-think the way in which we build, operate, and decommission the built environment. Product-service systems (PSS) are a promising model for realigning environmental risks and responsibilities with financial and business objectives, while promoting much deeper and long-lasting collaboration between all parties involved in a building’s life-cycle. This thesis focuses on the building envelope, as one of the most performance-determining systems in our buildings. It then questions the technological, managerial, financial, and legal contexts which often perpetuate unsustainable linear practices despite the urgency for - and technical feasibility of - more energy- and resource-efficient alternatives. Facades-as-a-Service is a topic that extends far beyond technological readiness and architectural engineering. It is rather a thesis about how we make façade construction and retrofitting decisions, the systemic parameters that determine and constraint these decisions, and whether – in the search for a more sustainable built environment – we should question the fundamental concepts behind these decisions. The results show that gradual and strategic development with a multi-disciplinary perspective can enable and facilitate the implementation of more efficient and sustainable building practices.

Assessing Energy Performance Improvement Potential of Traditional Housing in North-Eastern India Through Building Energy Simulation

Assessing Energy Performance Improvement Potential of Traditional Housing in North-Eastern India Through Building Energy Simulation

공공건물 그린리모델링에 따른 에너지사용량 분석 연구

The government is promoting efficient remodeling by minimizing energy consumption by improving the performance of passive and active technologies for energy efficiency of existing public buildings. This study analyzed the energy performance improvement effect before and after green remodeling through simulation results and actual energy consumption of existing public buildings, which are demonstration sites. As a result of measuring the airtight performance of the target building that has completed remodeling, it has improved by about 16%. As a result of ECO2 simulation analysis reflecting field measurement values of sealing performance, primary heating energy consumption and primary cooling energy consumption were reduced by 25.3% and 9.4% through remodeling. Actual energy consumption decreased by 34.2% on average after remodeling compared to before remodeling. The difference between simulation results and actual energy consumption was compared. The result of ECO2 simulation was high. In order to improve the reliability of energy simulation tools, it is judged that additional analysis is needed for the effect of each remodeling application technology. It is considered necessary to compare the actual energy consumption before and after remodeling for many buildings in the future.

Performance Analysis for Energy-Efficient Comparators

This work studies three different comparator proposed in recent years. Compared to the strnongARM latch as well as the Elzakker’s comparator, the dynamic comparator added cross-coupled devices that keeps the pre-amplifier’s integration nodes from fully discharge to the ground and thus improves energy performance. The dynamic bias latch-type comparator is an innovative design which added a tail capacitor to the pre-amplifier in order to block off the discharge route between the internal nodes and the ground. Though this design reduced the energy consumption significantly compared with the Elzakker’s comparator, it results in longer delay and only little improvement on the input-referred noise. The FIA dynamic comparator implemented a floating inverter amplifier (FIA) that utilizes a reservoir capacitor which cuts off its charging path and discharging path significantly reduced the energy consumption and improved noise performance to power itself.

A guideline to support the use of off-site solutions for façade retrofitting through BIM-enabled processes

The Architecture, Engineering and Construction sector requires an intense innovation process to reduce costs, intervention times, and improve energy performance. This is particularly true to increase the rate of deep renovations of the existing European building stock and therefore support the EU’s 2050 decarbonisation targets.In this scenario, prefabrication can be considered a game-changer for the construction industry: on the one hand, it enables the adoption of an industrial mindset to the design, manufacturing, and installation of façade components, with the related advantages in terms of time, cost and quality; on the other, it allows for the customisation of components thanks to digital, BIM-based design and fabrication tools. However, its adoption in retrofit operations is still limited due, among other factors, to a lack of practical experience and a limited number of actual demonstration cases.This paper introduces an operative guideline to support a more widespread use of prefabricated thermal insulation components for the energy retrofit of existing buildings in the framework of a BIMenabled design and construction process. The guideline highlights the information flow and the role of each actor at every stage of the design and delivery process.The proposed guideline is finally tested through its application to a case study to show the feasibility of the process and the advantages deriving from the adoption of an industrialised approach to façade retrofit in terms of faster installation times.

Eco-Driving Control Architecture for Platoons of Uncertain Heterogeneous Nonlinear Connected Autonomous Electric Vehicles

The improvement of energy performance for platoons of autonomous connected vehicles is one of the major challenges the road transport sector is facing with. To this aim, this work addresses and solves the energy-consumption problem for uncertain heterogeneous electric nonlinear autonomous vehicles platoon via a novel Eco-Driving Control Architecture able to optimize its energy consumption performance while ensuring the fulfillment of the optimal leader tracking trajectory. Specifically, it consists of a Nonlinear Model Predictive Control (NMPC) strategy, driving the leader motion and computing the optimal ecological trajectory to be imposed on the whole platoon, and a novel distributed exponentially-stable robust PID-like protocol, driving the follower vehicles motion for achieving a precise leader-tracking with a desired transient behavior as required for the accurate implementation of the energy-saving control. The exponential stability of the overall vehicular network is analytically proven with the Lyapunov theory and the derived robust stability conditions allow the proper tuning of the control gains on the basis of the desired decay rate. The efficiency of the proposed approach is corroborated via the high-fidelity Mixed Traffic Simulator (MiTraS) co-simulation platform under different operative scenarios and a wide uncertainty range for the vehicles parameters. Simulation results confirm how the proposed architecture ensures the eco-driving behaviour for the whole vehicles platoon.

Measurement and Diagnosis of Comfort in a Historic Building

Historic buildings constitute a specific group of buildings where the possibilities of improving energy efficiency and comfort are significantly limited because of the existing construction features and heritage values. Each building has a different history so the scope of renovation and/or retrofitting must be determined individually for each building. This article presents the methodology of measurement and diagnosis of features of particular importance for energy performance and comfort improvements, based on the example of a historic masonry building located in southern Poland. The first research question was which of the comfort conditions have been exceeded according to measurements. The second issue concerned the necessary extension of the basic determinants of comfort, beyond measurable qualities. A multi-faceted approach to the comfort assessment is proposed, including qualitative research that applies the additional criterion of aesthetic comfort. During the case study diagnosis, the acceptable level was exceeded in thermal, acoustic and aesthetic comfort. The first two may be addressed by optimized technical measures whilst the latter through a research-through-design that addresses the complex relationship between the perceiver and what the environment affords. The solution reflects the need to meet demands for retrofits that are energy-efficient and aesthetically pleasing while minimizing any negative impacts on the heritage and the environment.

Energy effectiveness analysis of desiccant coated heat exchanger based on numerical method

The conventional air-to-air heat pumps rely heavily on the condensation dehumidification principle to regulate air humidity, thereby severely limiting the system energy efficiency. Significant energy efficiency improvements can be realized by coating high-performing solid desiccants on both evaporator and condenser heat exchangers. Thus far, existing fundamental analysis developed to evaluate energy performance improvement and achieve accurate performance prediction of desiccant coated heat exchangers with two-phase refrigerant (DCHERs) has been impeded by the complex physical phenomena, approximations in the heat/mass transfer paths, and the severe reliance on the use of empirical correlations. Therefore, in this work, a mathematical approach has been judiciously developed based on mass, momentum, energy, and species conservation principles in order to study the flow field distribution within DCHERs and predict their performance. The model is extensively validated with experimental data obtained under various working conditions with discrepancies of ±10 % and ±9 % for outlet air temperature and humidity, respectively. The model provides essential information on local temperature and humidity distributions, and key insights on the transient heat and mass transfer phenomena. Further, a general design guideline for the performance enhancement of DCHERs is established. Key results from the study reveal that the air RH varies within 15 % along the DCHER’s flow channel. Thick desiccant coating, high inlet air relative humidity, and long air-desiccant contact time markedly improve latent energy effectiveness to a maximum of 0.51. Lastly, employing the proposed guideline to design the heat exchanger with optimal tube configurations yields a 23 % enhancement of latent energy effectiveness.

Air Cavity Building Walls: A Discussion on the Opportunity of Filling Insulation to Support Energy Performance Improvement Strategies

The paper intends to discuss the use of cavity wall insulation in existing buildings for energy improvement. Cavity walls are widely spread throughout the EU, typically in buildings from the 20th century, which are recognized as the subject of urgent and deep energy renovation interventions. Their main characteristic is an empty air cavity between two layers of building materials (typically brick, stone, or concrete). Filling the empty air cavity with insulating materials reduces energy loss by transmission through opaque envelope surfaces, and therefore, it represents a cheap solution to obtain a significant reduction in building energy consumption. Various aspects should be carefully evaluated for the effectiveness of this type of intervention: The first step is knowing the materials’ behavior depending on their thermal and hygrometric parameters (conductivity and transmittance, thermal bridge transmittance, vapor permeability, and resistance to vapor diffusion). Some indications on limits or reference/target values are usually given by national/regional laws and EU Directives. The filling insulation could lead to collateral problems (thermal bridges, risk of vapor condensation inside walls, etc.). To help understand the relevance and the impact of this insulation technique, an example of the assessments of a common cavity wall type is presented. The analyses highlight the usefulness of an organized and systematic database on building envelope features to set targeted energy-saving actions. Public administrations could base their strategies on this information to promote the reduction of energy consumption on a large scale with efficient and economically sustainable interventions. In the absence of more specific databases, the Energy Performance Certificates (EPC) data consulting could help develop thermal insulation strategies at a regional/national level. In particular, the diffusion of cavity walls can be obtained as a function of wall surface and cavity thickness for estimating the energy saving potential, economic impact, and general feasibility of systematic insulation-filling actions. An example of this kind of database analysis is discussed and carried out on a regional scale to explain how it could represent a useful approach to evaluate potential energy-saving interventions. The sample building stock provides suggestions on the possibility to extend the considerations on a larger scale to help set systematic energy-saving strategies.

Development of a Solar Tracking-Based Movable Louver System to Save Lighting Energy and Create a Comfortable Light Environment

Louvers are among the technical components considered for improving energy performance in buildings, and there has been increased interest in adapting the louver system. However, most previous studies have focused on their performance evaluation based on the width and angle of the slats, which allow for limited improvement in their efficiency. This study suggests a solar tracking-based movable louver (STML) system and examines the efficacy using a full-scale test bed. To do so, we developed a full-scale test bed and estimated the energy reduction and improvement of indoor uniformity of different types of STML systems, including vertical, horizontal, eggcrate, and hybrid. The main findings are as follows: (1) The proposed STML is a hybrid louver with four movable shafts due to its structural characteristics. The shading area is increased sequentially by controlling the length of the movable shaft adjacent to the sun through solar tracking. (2) Compared with conventional vertical and horizontal louvers, the STML can improve indoor uniformity by 5.0% and 13.9%, respectively. Unlike conventional louvers, the STML awnings are installed at the end of the daylighting window, reducing window view obstruction and creating a more pleasant indoor visual environment. (3) Compared with conventional louvers, the STML can reduce lighting and heating/cooling energy by 35.7–49.7%. These findings prove the effectiveness of the proposed system.

Thermal performance assessment of a retrofitted building using an integrated energy and computational fluid dynamics (IE - CFD) approach

The comfort of the occupant in the indoor thermal environment can be efficiently analysed using the principle of computational fluid dynamics (CFD) technique. This can be modelled as a difference of measure of a region equivalent to air circulation and diffusion in/out of the area. Other parameters influence the room operating condition and energy consumption by the building systems directly and indirectly over a period of time. This paper represents how to use comfort theory and CFD concepts to do a computational study of building comfort and improve the energy performance of the building during the summer and winter seasons in the subtropical climate. The occupants’ overall comfort evaluation results in the chosen building are recorded, taking into account the suitable climate-responsive heating, ventilation and air conditioning approach and envelope systems. The thermal CFD simulation model used in this study incorporates the most current turbulence simulation methodology appropriate for airflow modelling in buildings. The numerical comfort analysis methodology is used to analyse the indoor thermal condition, considering the Cooled Beam cooling system and BioPCM as an envelope solution for possible retrofitting. The simulation findings show that the uniform temperature distributions observed during working hours are adequate and demonstrate improved energy performance by the building systems. Moreover, the results suggest that the use of advanced computational fluid dynamics techniques is a valuable method for the analysis of human comfort in indoor spaces.

지하철역사 에너지성능 평가를 위한 클러스터링 분석기법을 활용한 지하철역사 대표모델 선정에 관한 연구

In order to realize the government’s plan to increase zero energy early and play a leading role in the low carbonization of railway facilities, Since 2025, the National Railroad Corporation has established a Zero Energy Roadmap for railway stations to promote zero energy building certification. However, currently, standards and tools for evaluating various railway history, including subways, are insufficient in Korea. In particular, railway history has characteristics that are distinct from general buildings, such as the presence of peak loads, continuous erosion, and the possession of safety and functional elements that must be equipped Accordingly, an alternative is needed to overcome the limitations of existing domestic energy performance evaluation tools developed for general building evaluation. Therefore, this paper uses the clustering technique as the first step to develop a decision-making tool that presents the energy performance evaluation and improvement direction of railway history It can represent the characteristics of subway history. In order to select a representative model, data collection and clustering analysis of all 291 subway stations in the Seoul area were performed using Open Data provided by the public data portal. K-means and GMM algorithms were used as clustering analysis methods. As a result of clustering analysis, the K-means algorithm was difficult to use as a result of classification because the data columns were diverse and were not in the form of circular distribution by cluster. Compared to K-means, GMM algorithms can significantly distinguish characteristics such as area, completion year, and platform type the results were shown.BRThe representative standard stations selected based on the results of GMM clustering were Konkuk University Station (Line 2), Suraksan Station, and Hongdae Station. After that, through simulation of representative models and multiple regression analysis using results, the standard model is developed and used as a tool for initial decision-making such as zero energy construction plan and remodeling plan for subway stations.

End-use energy indicator approach to improve energy performance at the National University of Colombia Bogotá, under the parameters of the ISO 50001 standard

The university belongs to the services sector, which is why it cannot implement traditional industry indicators such as energy consumption per unit produced. For this reason, we propose indicators for the final use of energy. The indicators were developed through an energy review process of the information in the database of advanced energy meters with the support of the Specialist in Geographic Information Systems of the Environmental Management Office (EMO). Additionally, we considered several existing reports that characterized the final use of energy for some buildings and essential data for defining the percentages each final use will have within the conglomerate of loads registered. Continuity was also given to this process by collecting face-to-face information with the support of each building’s environmental manager. This article shows the behavior of two buildings of the National University Bogotá, the Uriel Gutiérrez building and the Roberto Franco Station, to propose an indicator of final energy use. This approach enabled determining in which end-use the load has the highest consumption, taking into account that this may contribute to the management system energy of the university. This article uses the guidelines implemented in the ISO 50001 standard.

Problematic Use of Cannabis in Cotonou: Profile of Some Subjects Received in the Laboratory between 2016 and 2021.

The frequent use of cannabis by certain social strata often induces behavioral changes whose severity deserves to be evaluated. This study aims to describe the profile of some subjects in a situation of cannabis dependence received at the National Laboratory of Narcotics and Toxicology over the period from January 2016 to December 2021. Methodology. The approach of direct interviews with the respondents using a semistructured questionnaire made it possible to collect their sociodemographic characteristics, their experiences, and their reference trajectories. A total of 48 patients, all single, with an average age of 18.13 ± 0.48 years, the majority of whom were male (77.08%) and of Beninese nationality (85.42%), were enrolled. They were pupils (58.34%), students (27.08%), and workers (14.58%). With a prevalence of consumption of 89.58%, the first experimentation of cannabis was done by imitation (83.3%), among friends (81.2%), and in schools (64.58%). The reasons for use include the search for thrills (29.20%) and the improvement of sexual energy performance (27.1%). Subjects between 64.58 and 79.17% reported having received complaints about their behavior after regular consumption of at least 3 joints of cannabis. The knowledge of the typical profile of subjects in a situation of dependence ensures early detection of problematic uses of cannabis and offers the opportunity to intervene a little earlier in front of this phenomenon.

Evaluating the performance of a hybrid cooling and heating power system using Carbon dioxide energy storage

Energy storing could correct an imbalance in the solar to electric power ratios among a Combined Heating, cooling and power system and its consumers, improving energy performance dramatically. Energy storage, on the other hand, adds to the complexities of the device’s operational efficiency. While assessing the device’s CO2 emissions in the operational state, the analysis comprises complete thermodynamics and thermo-economic evaluation. The effect of designing element modification on application functionality was examined next by varying the designed characteristics. Lastly, the proposed hybrid CCHP system is optimized for three objective operations: normalized exergy performance, CO2 emissions, and energy effectiveness. This paper presents a unique tri-generation method depending on the Trans-critical Brayton cycle and carbon dioxide energy storage (CO2ES). The stored capacity has a minor impact on the framework’s operating and cooling ranges, but the development in pressure change through the first throttle valve and temperature conditions broadens them. The capacity for heating and cooling rises in lockstep with stored pressures and falls in lock-step with differential pressure via the first throttle pressure regulator and ambient temperature. Moreover, the computational power is adequate for power system management. The proposed approach could also be used to optimize the functioning of a CCHP framework while taking into account demand-side responses.