Search Results (19)

Most of the dam structures around the world are approaching the end of their economic life of 50 to 70 years, especially due to sediment accumulation in reservoir areas. This situation necessitates the development of proactive infrastructure management strategies. This study presents an original framework for the process of renewal of aging dams that blends remote sensing techniques and meta-intuitive optimization methods. Within the scope of the study, the Hasanlar Dam located in Düzce was selected as a sample, and a new dam axis was determined in the upper part of the basin. A detailed volume–height curve was created using 12.5 m resolution ALOS PALSAR numerical height models (DEM) and GIS-based spatial data curation to calculate the reservoir storage capacity in precise increments of 2 m. To maximize the structural efficiency of the proposed “New Hasanlar Dam”, the cross-sectional area has been minimized through seven current algorithms such as Genetic Algorithm (GA), Arithmetic Optimization Algorithm (AOA), Gray Wolf Optimizer (GWO), Dragonfly Algorithm (DA), Particle Swarm Optimization (PSO), Crayfish Optimization Algorithm (CAO), and Cheetah Optimizer (CO). The findings obtained prove that the PSO and CAOs achieved a significant reduction in cross-sectional area by 29.36% and successfully approached the global optimum. The replacement of the 55.5 million m³ capacity of the existing Hasanlar Dam with a new structure with a height of 78 m will guarantee sustainability and structural safety in water management. As a result, this study reveals that the integration of high-resolution remote sensing data and advanced heuristic methods is a cost-effective and powerful tool in the strategic renovation of aging hydraulic infrastructures. Full article

Building energy renovation planning should be based on a multi-criteria evaluation that targets both reduced energy consumption and a high-quality indoor thermal environment. The present study investigates the building energy retrofit technologies of thermal insulation, highly insulative windows, mechanical ventilation for cooling purposes, and shading, aiming to identify the optimum energy retrofit strategy for different building typologies. Indoor thermal comfort is evaluated with the thermal comfort indexes of the predicted mean vote (PMV) and the Predicted Percentage of Dissatisfied (PPD). Each renovation scenario is evaluated in terms of thermal performance and thermal comfort, while an optimum retrofit scenario is defined as the one that simultaneously achieves the maximum decrease in the yearly energy demand and the greatest decrease in the building’s indoor thermal discomfort. The multi-objective analysis is performed using the EnergyPlus simulation engine, which is used to perform yearly dynamic simulations and provide accurate results. This study considers a typical one-story apartment building located in the city of Athens, Greece. According to the calculations, the retrofit strategy that combines all four examined interventions results in an 11.8% and 56.1% decrease in the building’s heating and cooling energy demand, respectively, while an annual enhancement of 16.6% in the building’s thermal comfort PPD index is calculated. Full article

Sustainable renovation is a critical aspect for designing energy-efficient buildings with reasonable cost and high indoor living standards. The objective of this paper is to investigate various renovation scenarios for an old, uninsulated building with a floor area of 100 m² located in Athens, aiming to determine the global optimal solution through a multi-criteria analysis. The multi-criteria analysis considers energy, economic, and thermal comfort criteria to perform a multi-lateral approach. Specifically, the criteria are: (i) maximization of the energy savings, (ii) minimization of the life cycle cost (LCC), and (iii) minimization of the mean annual predicted percentage of dissatisfied (PPD). These criteria are combined within a multi-criteria evaluation procedure that employs a global objective function for determining a global optimum solution. The examined retrofitting actions are the addition of external insulation, the replacement of the existing windows with triple-glazed windows, the addition of shading in the openings in the summer, the application of cool roof dyes, the use of a mechanical ventilation system with a heat recovery unit, and the installation of a highly efficient heat pump system. The interventions were examined separately, and the combined renovation scenarios were studied by including them in the external insulation because of their high importance. The present study encompassed the investigation of a baseline scenario and 26 different renovation scenarios, conducted through dynamic simulation on an annual basis. The results of the present analysis indicated that the global optimal renovation scenario, including the addition of external insulation, the installation of highly efficient heat pumps, and the use of shading in the openings in the summer, saved energy by 74% compared to the baseline scenario. The LCC was approximately EUR 33,000, the simple payback period of the renovation process was around 6 years, the annual CO₂ emissions avoidance reached 4.6 tn_CO2, and the PPD was at 9.7%. An additional sensitivity analysis for determining the optimal choice under varying weights assigned to the criteria revealed that this renovation design is the most favorable option in most cases. These results prove that the suggested renovation scenario is a feasible and viable solution that leads to a sustainable design from multiple perspectives. Full article

Rural residential structures account for a substantial share of carbon emissions within the construction industry. Enhancing building envelopes can diminish structural carbon emissions, thereby facilitating the attainment of “dual carbon” objectives. Current algorithm-driven research on the low-carbon retrofitting of residential building envelopes generally neglects temperate regions in low-latitude plateaus, often misses embodied carbon, and utilizes rather limited methodologies for issue identification. This study focuses on rural dwellings in Lijiang, utilizing a cross-validation method that incorporates sensitivity analysis, infrared thermal imaging, and energy efficiency criteria to systematically identify vulnerable regions in the building envelope. Consequently, critical issues are converted into optimization variables for the NSGA-II method, aiming to minimize both embodied carbon and operational energy usage. BAPV is concurrently implemented to partially mitigate renovation expenses. A weighted summation approach delineates stakeholder preferences, resulting in three optimum options. The findings reveal that all three methods correspond to their unique preferences, illustrating distinct trade-offs among energy efficiency, carbon reduction, and economic feasibility. The government-oriented approach attained an energy saving rate (ESR) of 45.11%, a life cycle carbon reduction (LCCR) of 1215.76 kgCO₂/m², and a dynamic payback period (DPP) of 3.65 years. The architect-oriented approach realized the highest energy savings and carbon reduction (45.41%, 1218.96 kgCO₂/m²), with a payback period of 3.99 years. The villager-oriented approach emphasized economic viability, achieving an energy savings rate of 41.55%, a carbon reduction of 1149.46 kgCO₂/m², and the shortest payback period of 2.87 years. This study provides an optimization process and reference parameters for building envelopes in a low-carbon design for residential buildings in temperate regions of low-latitude plateaus. Full article

To achieve climate goals, the European Union needs to increase building renovation rates. In owner-occupied buildings, energy cost savings provide financial incentives for renovation. However, 30% of all Europeans live in rented property, where conflicting stakeholder interests arise. Landlords are responsible for renovation decisions (building envelope and energy system) and the corresponding investments. Tenants face rising rents and only slightly benefit from falling energy costs. The literature calls this conflict the landlord–tenant dilemma. However, publications lack a quantification, leaving gaps in understanding its impact on technology choices and the heat transition. To address this, we incorporate the perspectives of landlords and tenants in a model-based approach for optimized technology choice (mixed-integer linear program). We compare optimal individual technology choices with the total cost optimum (including costs for landlords and tenants) for renovation decisions. Additionally, we examine how changes in the regulatory framework affect the economically driven landlord’s technology choice. Our study reveals that total costs and emissions are up to 60% and 283% higher for landlords deciding for rented houses compared to owner-occupied properties. Current approaches to solve the dilemma partly favor the development of climate-friendly energy systems. However, the renovation of the building envelope and operation costs are mostly disregarded in the decisions of landlords. Full article

The built environment contributes to 35% of the global energy consumption and 38% of energy-related carbon emissions. The exponential population growth, coupled with the inability of the existing building stock to meet demands or reach the end of its lifespan, has precipitated the proliferation of new constructions worldwide. However, it has been proven well that retrofitting existing buildings might impact the environment less, save resources, and reduce the carbon footprint while extending their lifecycle. Various techniques are available to assess the performance of existing buildings and quantify the energy-saving potential of renovation measures. Building information modeling (BIM) technology serves as a virtual laboratory for buildings and can be used to model building stocks and measure how building performance changes with alternative envelope and system proposals. This research study explores the potential of BIM-based energy modeling to evaluate the effectiveness of refurbishment scenarios on a residential building. A total of 192 alternative scenarios were developed by considering six variables (wall, roofing, insulation, glazing, lighting power density, and photovoltaic panels). The results were analyzed across annual energy consumption (fuel and electric), annual/lifecycle energy costs, energy use intensity, annual CO₂ emissions, and initial investment costs. The optimum alternative scenario decreased the annual fuel and electricity consumption of the sample building by 61% and 64%, respectively. The payback period was calculated as 12 years. This study demonstrates the impact of BIM in enhancing the energy efficiency of the existing building stock, presenting results within the context of a residential building. Full article

The construction industry has extensively applied the fast-tracking approach to the demanding need for the fast delivery of infrastructure projects. However, the fast-track strategy might be threatened by distinctive risks or changes in risk characteristics that emerge when activities are overlapped (overlapping risks). This article proposes a risk assessment simulation model to quantify the economic impact of overlapping risks on fast-track infrastructure projects. The model uses Monte Carlo simulation and a proprietary engine solution for the optimization procedure. It quantifies the overlapping risk impacts in the project duration and cost that could originate in three different overlapping degrees and evaluates the optimal overlapping degree to reduce the impact of the overlapping risks. The model demonstration used a commercial renovation project. The results suggest that overlapping risks have a high potential impact on the total cost, although with a high probability of attaining the target duration. Eight top risks affected the total duration, cost, or both. The optimum overlapping to reduce the economic impact and achieve the target project duration combines different overlapping degrees. This study contribution is a model for fast-track projects considering overlapping risks, their impact characteristic as a distribution, and the potential relationship between these risks. Full article

Natural resources are declining due to rising infrastructure, renovation, demolition, and recycling of existing structures that necessitate sustainable development. It urges the researchers to modify the aged asphalt binder in the recycling to enhance the performance life of asphaltic pavements. The aim of this research study is to reutilize recycled materials through rejuvenation. This study utilizes the Cereclor to rejuvenate the aged binder collected from recycling and explore its transformation by comparing it with parent binder of similar grade. Different types of tests, such as basic physical properties, saturates, aromatics, resins, and asphaltenes (SARA) analysis for the fractional composition, bending beam rheometer (BBR), and dynamic shear rheometer (DSR) for rheological properties are applied to investigate these properties and effect on the performance. The results show that rejuvenator improved the fractional composition of the aged asphalt binder. It significantly improved the physical properties of the binder. The asphaltene contents are reduced up to 18% in the fractional composition through the addition of the optimum dosage (7.5%) of the rejuvenator. The colloidal instability index was decreased from 0.74 to 0.43 value by changing its unstable to stable colloidal structure. In addition, rejuvenator improved the rheological properties at a wide range of temperatures. The rejuvenator has the potential to soften the aged binder through optimum dosage (7.5%), as indicated in the results of fractional composition, colloidal structure, and rheological properties. Furthermore, it has been concluded that it can be utilized as a rejuvenator in the recycling industry to resolve the recycled materials disposal issues and lead to promote sustainable development. Full article

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

Buildings are known to be responsible for about a third of energy consumption in developed countries. This situation, together with the fact that the existing building stock is being renovated at a very slow pace, makes it crucial to focus on the energy retrofitting of buildings as the only way to reduce their contribution to these energy consumptions and the consequences derived from them in terms of pollution and climate change. The same level of insulation and the same type of windows is usually proposed for all dwellings in a building block. This article shows that since the improvements required by each dwelling in the same block are different, the proposed solution must also be different. The methodology is proposed for a practical case consisting of an apartment block in Cádiz, a demonstration building of the European RECO2ST project. To achieve the optimum solution for each case, a multi-objective optimization problem is solved: to minimize the annual heating demand of the building and the standard deviation of the annual demand of the different dwellings. Thanks to the use of the proposed methodology, it is possible to bring the building to a Nearly Zero Energy Building (NZEB) level, while avoiding excessive insulation that causes overheating in summer. Full article

One of the greatest challenges facing the European Union is the conversion of the existing residential building stock into nearly zero-energy buildings (NZEBs) by 2050 through energy renovation, given that the residential sector is one of the largest consumers of final energy and that approximately two-thirds of existing dwellings were built before 1980. The objective of this study is to assess the energy, environmental, and economic impacts of the energy renovation of thermal envelopes of existing multi-family buildings in the hot and temperate climate zones of Spain by using life cycle cost analysis (LCCA) to determine the optimal thicknesses of insulation to be added to the walls, roof, and first floor framework of the buildings and replacing existing building openings to achieve NZEBs. Four thermal insulation materials are considered with four different heating and cooling systems and ten different models. With the methodology developed, the best energy renovation solutions are estimated and then thermally simulated. In total, 67 of the 576 proposed energy renovation solutions achieve NZEBs. This study fills in the gap between LCCA estimates and reality. Full article

(1) The overall energy requirement of a building may be impacted by the building design, the selection of materials, the construction methods, and lifecycle management. To achieve an optimum energy-efficiency level when dealing with a new building or renovation project, it is important to improve the entire construction process as it is not enough to merely focus on the operational phase. If conventional construction practices do not evolve, compromise, or adapt to necessary changes, then it becomes challenging to deliver an ultimate low energy building. (2) This paper demonstrates the trend of off-site prefabrication and its production principles and the notions of open-building design and Design for X, as well as offering an overview of the development of automation in construction, which provides both insights and evaluations based on the context of the research. (3) Three European Union Horizon 2020 research projects were evaluated, and the outcome of the projects served as the backbone for the research and inspired the design of the proposed integrated façade system. Two design scenarios were proposed to demonstrate the potential improvements that could be achieved in a new build as well as in renovation projects. (4) The research lays a foundation for establishing a larger cross-disciplinary collaboration in the future. Full article

The residential sector of the European Union consumes 27% of the final energy of the European Union, and approximately two-thirds of the existing dwellings in the European Union were built before 1980. For this reason, the European Union aims to transform the existing residential building stock into nearly zero-energy buildings by 2050 through energy renovation. The most effective method to achieve this goal is to increase the thermal insulation of opaque elements of the thermal envelope. This study aims to assess the energy, environmental and economic impacts of the energy renovation of the thermal envelopes that are typical of the existing multi-family buildings of the 26 provincial capitals in the cold climate zones of Spain. To achieve this goal, the insulation thickness to be added to the walls, roof and first floor framework is optimized by a life cycle cost analysis, and the existing building openings are replaced, thus minimizing both the total heating costs and the total heating and cooling costs. The study uses four thermal insulation materials for four different heating and cooling systems in 10 different models. The results obtained will be used to propose energy renovation solutions to achieve nearly zero-energy buildings both in Spain and in similar Mediterranean climate zones. Full article

Historic buildings, due to their architectural, cultural, and historical value, are the subject of preservation and conservatory works. Such operations are preceded by an inventory of the object. One of the tools that can be applied for such purposes is Light Detection and Ranging (LiDAR). This technology provides information about the position, reflection, and intensity values of individual points; thus, it allows for the creation of a realistic visualization of the entire scanned object. Due to the fact that LiDAR allows one to ‘see’ and extract information about the structure of an object without the need for external lighting or daylight, it can be a reliable and very convenient tool for data analysis for improving safety and avoiding disasters. The main goal of this paper is to present an approach of automatic wall defect detection in unlit sites by means of a modified Optimum Dataset (OptD) method. In this study, the results of Terrestrial Laser Scanning (TLS) measurements conducted in two historic buildings in rooms without daylight are presented. One location was in the basement of the ruins of a medieval tower located in Dobre Miasto, Poland, and the second was in the basement of a century-old building located at the University of Warmia and Mazury in Olsztyn, Poland. The measurements were performed by means of a Leica C-10 scanner. The acquired dataset of x, y, z, and intensity was processed by the OptD method. The OptD operates in such a way that within the area of interest where surfaces are imperfect (e.g., due to cracks and cavities), more points are preserved, while at homogeneous surfaces (areas of low interest), more points are removed (redundant information). The OptD algorithm was additionally modified by introducing options to detect and segment defects on a scale from 0 to 3 (0—harmless, 1—to the inventory, 2—requiring repair, 3—dangerous). The survey results obtained proved the high effectiveness of the modified OptD method in the detection and segmentation of the wall defects. The values of area of changes were calculated. The obtained information about the size of the change can be used to estimate the costs of repair, renovation, and reconstruction. Full article

A comprehensive case study on life-cycle cost analysis (LCCA) was conducted on a two- story education building with a projected 40-year lifespan in College Park, Maryland. The aim of this paper was to (1) create a life cycle assessment model, using an education building to test the model, (2) compare the life cycle cost (LCC) of different renovation scenarios, taking into account added renewable energy resources to achieve the university’s overall carbon neutrality goal, and (3) verify the robustness of the LCC model by conducting sensitivity analysis and studying the influence of different variables. Nine renovation scenarios were constructed by combining six renovation techniques and three renewable energy resources. The LCCA results were then compared to understand the cost-effective relation between implementing energy reduction techniques and renewable energy sources. The results indicated that investing in energy-efficient retrofitting techniques was more cost-effective than investments in renewable energy sources in the long term. In the optimum scenario, renovation and renewable energy, when combined, produced close to a 90% reduction in the life cycle cost compared to the baseline. The payback period for the initial investment cost, including avoided electricity costs, varies from 1.4 to 4.1 years. This suggests that the initial investment in energy-efficient renovation is the primary factor in the LCC of an existing building. Full article