Search Results (89)

Aging residential buildings in urban areas require effective thermal insulation to enhance energy efficiency and indoor comfort. In Bosnia and Herzegovina (BiH), expanded polystyrene (EPS) is the most commonly used insulation material due to its affordability, despite concerns regarding its flammability and environmental impact. While regulatory changes since 2019 have recommended rock wool for high-rise buildings, the absence of binding fire safety regulations has allowed the continued use of EPS, often driven by financial constraints. This study examines energy efficiency refurbishments in Sarajevo’s high-rise residential buildings and analyze the implications of the partial implementation of recommended measures. Using case studies, surveys, and expert interviews, this research identifies key challenges, such as limited funding, fragmented renovations, and inconsistent coordination between stakeholders. The findings indicate that facade insulation is often prioritized over comprehensive upgrades, including window replacement and heating system improvements, leading to suboptimal energy savings and minimal cost reductions for residents. Additionally, the complexity of multi-apartment ownership structures hinders uniform improvements in energy efficiency. Despite these challenges, property values tend to increase after renovation, highlighting the long-term financial benefits. To maximize energy savings and ensure sustainable urban housing, stronger interdisciplinary collaboration, improved funding mechanisms, and adherence to fire-safety standards are necessary. These measures would enhance the effectiveness of renovations and support long-term energy efficiency strategies. Full article

The construction sector plays a pivotal role in urban development, providing a critical opportunity to foster a cultural shift towards the regeneration of housing stock. This shift focuses on sustainable and resilient urban interventions to extend the lifespan of buildings, starting from the design phase. In this context, the European Union’s Level(s) framework, which establishes sustainability indicators, is particularly relevant to this research, as it promotes circular economy principles and building resilience. The framework provides a comprehensive set of indicators that guide resilient housing rehabilitation methodologies. Indicator 2.3 supports the design and renovation of obsolete housing, emphasizing the maximization of resilience against climatic, functional, and socio-economic impacts. Meanwhile, Indicator 4.2 evaluates the thermal comfort of building occupants concerning indoor conditions throughout the year. The primary aim of this study is to develop a resilient housing rehabilitation methodology based on Level(s), which includes (i) assessing the current resilience of a pilot case, (ii) designing new resilient housing configurations, (iii) evaluating thermal comfort duration for older adults, and (iv) analyzing cost amortization. The research findings indicate that the proposed rehabilitation approach significantly improves occupants’ resilience to climate-related stressors and thermal comfort, particularly vulnerable populations such as older adults. Additionally, the study highlights the importance of adapting thermal comfort standards for these populations and demonstrates the cost-effectiveness of resilience strategies. The outcomes contribute to a flexible and accessible refurbishment model that meets diverse tenant needs, offering a scalable solution for sustainable urban interventions. Full article

This study focuses on the development of an insulation biocomposite using Doum palm (Chamaerops humilis) fibers reinforced with a natural binder based on citric acid and glycerol. The main objective is to optimize the thermal conductivity and mechanical properties of the biocomposite as a function of fiber preparation (short or powdered fibers) and binder content (20%, 30% and 40%), and relate them to the bonding of the fibers and the binder. The obtained results suggest that the addition of the binder greatly enhances the density, compressive strength and Young’s modulus of biocomposites. More specifically, the addition of 20% by weight of the citric acid/glycerol binder improves the bond between fibers, whether they are short fibers or powders. This leads to an increase in the mechanical properties, with Young’s modulus reaching (212.1) MPa and compressive strength at (24.3) MPa. On the other hand, the results show that these biocomposites also have acceptable thermal insulation performance, achieving a thermal conductivity of (0.102) W/(m·K), making them suitable for a variety of applications in sustainable buildings and for refurbishment. Full article

The construction sector has a high environmental impact, especially due to C&D waste. At the same time, the increase in the temperature of the Earth’s surface due to pollution requires interventions on the built environment, aimed at improving the performance of the envelope in hot climates. In the literature, there are studies on components to increase thermal efficiency, but they are limited by long or expensive production processes or high environmental impact. This research considers Italy as a reference area. The aim of this research is to design, prototype, and verify a sustainable component to be included in the stratigraphy of light mass vertical closures to increase their heat capacity that allows for the reuse of C&D waste and the optimization of site operations both in the selective demolition phase and in the redevelopment phase of the building. The method follows the following phases: analysis of the type of waste from C&D, analysis of international best practices, analysis of the possibilities of intervention on vertical closures according to the pre-existing structure and choice of cases of greatest scientific interest, design of the sustainable big bag by reusing inert materials from selective demolition and recycled polypropylene fabrics, prototyping and verification by laboratory tests, and software analysis to verify the thermal advantage. The use of the sustainable big bag allows for construction advantages, facilitating site operations both in the construction and waste disposal phases, energy advantages by improving the heat capacity of the envelope, and increases in the sustainability of the intervention through the reuse of waste materials. Full article

In the near future, the building sector will continue to absorb the greatest share of primary energy worldwide. It is necessary to find innovative solutions that promote energy efficiency through renovation measures, especially in historical buildings, for which refurbishment is constrained by several issues. In this study, we propose a novel Trombe Wall configuration that is easily integrable and based on a rock wall made of caged stone to use as a thermal accumulator. The system was investigated preliminarily using a transient Finite Difference Method (FDM) code to analyse the temperature field inside the rock wall. Successively, FDM results were employed as input data in TRNSYS simulations to determine the savings achievable in thermal heating requirements. The results demonstrated that the proposed solution, in the considered climate and on a reference historic building, can produce monthly heating savings varying between 26% and 85%. So, the rock wall results in a reliable solution for buildings in which refurbishment is difficult, allowing for preserving aesthetic features and improving energy efficiency by rationally using solar radiation. Full article

Dynamic simulations can accurately estimate the thermal demands for space heating and cooling in buildings, as well as the energy and economic performance of specific energy refurbishment actions. This study aims to evaluate the energy and economic savings resulting from the adoption of particular energy measures applied to a cluster of residential condominium buildings, also considering some possible Italian funding policies. To this scope, dynamic simulation models of several buildings with different features in terms of geometry, shape, and thermo-physical properties are considered. The selected buildings are representative of the most common buildings in the city of Naples, Southern Italy. Two scenarios regarding the possible penetration of the refurbishment actions are considered: the “25% scenario”, where 25% of buildings in the Naples municipality adopt the selected measures, and the “100% scenario”, where all buildings adopt such energy refurbishment actions. The results of the simulations, reported over different time periods, compare the economic, energy, and environmental benefits of the specific energy measures. This study evaluates the replacement of conventional natural gas-fired boilers with natural gas-fired condensing boilers, as well as the use of thermal insulation on the external walls of the buildings. The primary energy demand for space heating decreased by 28% when the proposed energy measures were implemented in all buildings of the Naples municipality. Full article

Heritage structures built in the 19th and 20th centuries in the western part of Romania are marked by the significant aesthetic influence of the Austro-Hungarian empire, with highly decorated façades facing the street and rather more simple surfaces towards the back and inner courtyard. This region is also marked by shallow earthquakes, which significantly affect the structural integrity of these buildings. Considering the current climatic context, energy efficiency regulations that also apply to the refurbishment of heritage structures, and the additional need by private owners and authorities to reduce the seismic vulnerability of these structures, it is necessary to develop integrated solutions that could improve the thermal performance of the building and strengthen its load-bearing structure, while preserving the highly valuable aesthetic features that are visible from the street. Therefore, this study is intended to investigate the viability of using different thermal rehabilitation solutions and materials that are suitable for the architectural characteristics of heritage buildings, while also integrating seismic strengthening solutions. These solutions are applied to a 19th-century building that comprises all the specific architectural and structural features found in the western part of Romania. It compares the effectiveness of using mineral-based insulation materials, cork and lime-based plasters, and aerogel–lime-based plaster applied to the inner or outer parts of the wall, depending on the solution. This solution to the problem will combine suitable wet, strengthening techniques that can be used on the inner part of the exterior walls without affecting the aesthetic value of the building. In this way, through the analysed results, this study provides valuable insights concerning potential suitable solutions that can be used to increase sustainability and reduce the seismic vulnerability of heritage masonry buildings. Full article

Recent earthquakes and escalating energy demands are exposing building stock deficiencies, particularly in terms of seismic resilience and energy efficiency. Many aged constructions do not fulfil current regulations both in terms of seismic and thermal design principles, thus requiring suitable retrofitting solutions. Integrated approaches for concurrent seismic and energy renovation have emerged as promising strategies in recent years, offering holistic solutions that optimize interventions and maximize benefits. While these combined methods hold significant potential for practical applications, there remain opportunities for further research to enhance their advantages. Furthermore, addressing climate concerns requires concentrated effort within the construction sector, where synergetic refurbishments can serve a dual purpose by reducing emissions and promoting the use of more sustainable materials. This study discusses strategies proposed in the literature for integrated retrofitting, considering their environmental impact, both in terms of energy performance and embodied carbon. The overview shows the innovation potential for the development of materials and systems combining acceptable performance with eco-friendly attributes. Yet, their application in integrated retrofitting systems, either as structural components or insulators, is still limited, underscoring the need for continued investigation and advancement. This paper concludes with recommendations to inspire further research and advancements in this critical field. Full article

Nearly zero-emission buildings (nZEBs) are increasingly being constructed in Europe. There are also incentives to refurbish older buildings and transform them into nZEBs. However, permission is not always granted for their connection to the grid to infuse surplus photovoltaic electricity due to the grid being overloaded with a large number of renewables. In this study, the case of a refurbished school building in Central Greece is examined. After refurbishing it, a significant amount of photovoltaic electricity surplus is observed during the summer and neutral months, which cannot be exported to the grid. The absence of an adequate battery storage capacity resulted in the rejection of an application for exporting the school’s surplus to the network and the photovoltaic installation staying idle. An alternative approach is proposed in this work, involving a shift in the export of the photovoltaic electricity surplus to the evening hours, in order for the school to be granted permission to export it to the network. To this end, an optimal battery storage size is sought by employing a building energy system simulation. The mode of operation of the battery designed for this application is set to discharge daily, in order to export the electricity surplus in the afternoon hours to the evening hours, when it is favorable for the network. Additionally, the optimal size of the thermal energy storage of the heating system is studied to further improve its energy efficiency. Our battery and storage tank size optimization study shows that a significant battery capacity is required, with 12 kWh/kWp photovoltaic panels being recommended for installation. The ever-decreasing cost of battery installations results in the net present value (NPV) of the additional investment for the battery installation becoming positive. The solution proposed forms an alternative path to further increase the penetration of renewables in saturated networks in Greece by optimizing battery storage capacity. Full article

Reducing the heat demand of existing buildings is an essential prerequisite for achieving a greenhouse gas-neutral energy supply. Numerous studies and open-source tools deal with heat demand mapping. It is not uncommon that estimated heat demands deviate from real heat consumption, so existing approaches should be improved by including in-depth building information. Some tools have recognised this problem and offer built-in functions for factoring various parameters into their assessments. Nevertheless, the necessary information is usually missing and should be obtained first. In this paper, we analyse the impact of thermal refurbishment and climate on building heat demand; hence, generate public datasets with corresponding key figures for each building type in different efficiency states and years. Accounting for already performed refurbishments in methodologies for assessing the actual state heat demand for cities will result in a reduction of at least 8% up to more than 21%, depending on whether conventional or passive house components were installed. As a result of climatic differences within Germany, a building’s heat demand can be up to 39% higher or up to 21% lower than the heat demand of an identical building in the reference climate of Germany. By further developing the approaches of the tools Hotmaps and Heat Cadastre Hamburg, we could improve the estimated heat demand of Hamburg to a value approximating the real consumption. Full article

The paper considers the issue of the thermal refurbishment of residential buildings built between 10 and 40 years ago in some European countries. It suggests that, while facade retrofitting is the most effective solution for older dwellings, all actions are equally less effective for newer dwellings built in this millennium. According to the current situation, as society shifts away from the use of fossil fuels, this paper presents the expected energy and financial savings that were calculated using one of four different heating sources. The study shows that the efficiency of the additional thermal retrofitting of the structures is low when the building is heated with a heat pump. The addition of thermal insulation to already well-insulated roofs or floors results in minimal savings of approximately 0.15 kWh per square meter of heated floor area per year. The potential advantage of replacing existing windows with new windows in a top thermal quality was shown. After window replacement, the financial benefits could be twice as high in houses heated by district heating compared to houses heated by gas or a heat pump, including an alternative heat pump with photovoltaics. Full article

Thermal refurbishment and retrofitting building envelopes with passive measures such as the optimisation of opaque and transparent fabric performance may play a key role in reducing cooling and heating load and promoting building energy efficiency. Furthermore, to reduce the embodied carbon impact of the building, the refurbishment measures need to consider the use of low-carbon building materials. This paper investigates ways to thermally future-proof typical Libyan houses using biobased materials. Several typical Libyan houses were monitored for one year to investigate the heating and cooling energy use and to thermally retrofit the building envelope. A digital twin was created in the DesignBuilder software using the real building data of one building for digital model calibration. Finally, multi-objective optimisation was carried out with low-impact biobased materials for insulation, including camel hair, sheep wool, and date palm fibre as well as using other optimisation variables such as shading and glazing types. The study reveals that thermally upgrading the building roof and wall with insulation materials and upgrading the windows with energy-efficient glazing and local shadings can achieve a reduction in cooling load from 53.51 kWh/m²/y to 40.8 kWh/m²/y. Furthermore, the heating load reduces from 19.4 kW/m²/y to 15 kW/m²/y without compromising the standard annual discomfort hours. Full article

An assessment of the thermal refurbishment of an outpatient medical center in a tropical location, such as the City of San Francisco de Campeche, was presented with the aim to diminish its energy consumption. A year-long energy audit of the facility was conducted to formulate and validate a numerical simulation model while scrutinizing enhancement strategies. The examined improvement alternatives encompass passive adjustments to the roof (utilizing insulating materials, applying reflective coatings, and installing a green roof), modifications to active systems incorporating inverter technology, and alterations to the walls via reflective paint. The outcomes of the simulated enhancement scenarios were assessed utilizing energy, environmental, and economic metrics: key performance index (KPI), equivalent CO₂ emission index (CEI), and net savings (NS). These results were subsequently juxtaposed against TOPSIS decision-making algorithms to ascertain the alternative that optimally balances the three options. It was identified that using reflective paint on the roof provides the best energy benefits and contributes to mitigating emissions from electricity use. Furthermore, combining this passive technology with the integration of inverter air conditioning systems offers the best economic return at the end of 15 years. For its part, the TOPSIS method indicated that by prioritizing the financial aspect, the reflective coating on the roof combined with inverter air conditioning is enough. However, adding a wall with insulating paint brings environmental and energy benefits. The results of this work serve as a starting point for the analysis of other post-occupied buildings in the region and others under tropical climatic conditions. Full article

The research presents approaches to the complex refurbishment of multi-family buildings constructed during the mass construction period in Serbia. These buildings comprise a quarter of Serbia’s housing stock, are characterized by high energy consumption for heating, and have major spatial and organizational deficiencies: small apartments, outdated and inflexible spatial organization, and the absence of elevators. The subject of the research is the application of the methodology of complex and integrated refurbishment by adding volume to existing multi-family buildings with the goal of achieving higher energy efficiency while remodeling and modernizing residential units and improving vertical building communications. The research presents a comparative analysis of the energy performance and spatial organization of the existing building and three variants of building improvement: Case 1 (without volumetric additions), Case 2 (with volumetric additions—relocating vertical communications), and Case 3 (with volumetric additions—expanding usable living space). Based on the Knaufterm simulations, the energy savings for heating energy consumption compared to the existing state are 81% in Case 1, 89% in Case 2, and 87% in Case 3. Based on predefined parameters of spatial comfort, a comparative analysis of spatial comfort in residential units was conducted for all three improvement variants. Full article

Micropiles are small-diameter foundation elements that are widely used in building refurbishment to reinforce existing foundations or provide new foundations where access for construction is difficult. Thermally-activated (TA) micropiles could be useful as an efficient means of providing cost-effective ground-coupling when shallow geothermal energy systems are considered in building rehabilitation. It is well-established that thermal activation of pile foundations results in thermo-mechanical interactions between the pile and the surrounding soil. These thermally-induced effects need to be examined to ensure that they do not adversely impact the load transfer function of the micropile. Numerical analysis is able to produce reliable predictions of thermo-mechanical behavior of TA piles, and this study applied this technique to examine the cyclic thermal behavior of micropiles, isolated and in groups. For the situations considered in this study, it is shown that during cyclic thermal activation, irrecoverable movements are unlikely to be significant in design terms, if the initial mobilization of the shaft resistance is low. Though stable, cyclic thermal movement amplitudes are large enough that they should be considered in design. The study highlights that large changes in thermal stress can develop and be locked-in to the response of long flexible piles, and that these should be verified in design. Further, as pile spacing reduces, thermal interference results in a loss of heat exchange capacity per pile, which has to be considered in the design of large groups of TA micropiles. Therefore, TA micropiles can offer an efficient and secure means of providing ground coupling in shallow geothermal energy systems. Full article