Search Results (7)

There is an issue in the building stock, especially in Europe, concerning energy efficiency and climate change adaptation. Due to insufficient thermal insulation and passive solutions, the majority of the existing buildings are not only ill-prepared for the negative effects of climate change, but they also contribute to higher energy consumption. The combination of smart materials and 4D printing for hygrothermal rehabilitation of building facades is the main topic of this review paper. The paper examines the application of smart materials in construction to overcome problems with moisture and heat transfer and other issues in the building envelope. It discusses numerous instances of this printing technology’s applications, such as particular responsive elements, identifies trends and draws attention to knowledge gaps in the field, and assesses environmental and economic impacts. The objective is to offer comparable data to aid in upcoming studies concerning the creation of 4D-printed building façade solutions. Additionally, the paper can be interpreted as a collaborative attempt to influence the direction of future hygrothermal building rehabilitation practices. It also aims to assist designers and other relevant parties in understanding the advantages, restrictions, and difficulties related to 4D printing and smart materials for the sustainable management of buildings. Full article

Thermal bridges significantly influence the energy performance of buildings. However, their impact varies depending on the type of thermal bridge, climate conditions, construction methodologies, and geometric characteristics of the building. On the Spanish Mediterranean coast, buildings with large balconies are predominant. Nevertheless, the Spanish energy efficiency regulations do not adequately specify the thermal bridges at the junctions of balconies with facades, leading to a lack of consideration for their influence in the majority of architectural projects. The objective of this study is to qualitatively and quantitatively assess the impact of such thermal bridges on the energy efficiency of buildings in a dry Mediterranean climate (BShs) within a warm semi-arid climate (BSh). As a case study, the influence of this thermal bridge is analyzed in two residential buildings located on the Mediterranean coast of southeastern Spain. The study also examines the modification of various construction parameters of this thermal bridge and determines the optimal design parameters to reduce its thermal transmittance. The results demonstrate that the energy needs caused by thermal bridges account for approximately 40% of the total annual energy needs of the studied residential buildings. Balcony thermal bridges account for 25% to 40% of the energy needs caused by all thermal bridges. The lack of differentiation in Spanish standards between balcony–facade and facade–slab edge junctions causes an imprecision in calculations equivalent to 12% of the total annual energy needs of dwellings. The novelty of this research lies in highlighting that current regulations and calculation programs need improvement to better characterize balcony thermal bridges and enhance the accuracy of building energy efficiency calculations. Full article

Carbon fiber reinforced polymer composites are widely used in the rehabilitation, repair, and strengthening of civil, marine, and naval infrastructure and structural systems. In these applications, they are exposed to a range of exposure conditions, including humidity and immersion, which are known to affect the durability of the resin and the fiber–matrix interface over long periods of time. This paper presents results of long-term hygrothermal aging of wet layup carbon/epoxy composites including through acceleration by temperature focusing on the development of a comprehensive understanding of moisture uptake kinetics and its effects on glass transition temperature and interface and inter-/intra-laminar dominated performance characteristics. A two-phase model for uptake that incorporates both diffusion- and relaxation-/deterioration-dominated regimes, as well as a transition regime, is shown to describe uptake well. The inclusion of damage terms to the diffusion and relaxation coefficients is seen to capture changes well, with the effective diffusion and relaxation coefficients increasing with fiber volume fraction and temperature. Effects of uptake, including at elevated temperatures, reflective of accelerated aging, on glass transition temperature and flexural strength are correlated, emphasizing a three-stage progression of overall response in line with the moisture uptake changes. The drop in glass transition temperature per percent increase in moisture uptake was seen to range from a low of 4.38% per % increase in moisture content, for the highest volume fraction at the highest temperature, to a high of 6.95% per % increase in moisture content, for the intermediate volume fraction at the lowest temperature. The composites with heavier fabric showed the greatest drop in both glass transition temperature and flexural strength, indicating a level of correlation between these characteristics as well. It is shown that both glass transition temperature and flexural strength show steep initial decreases, followed by a regime with slower decrease and, then, an asymptotic or near-asymptotic response with time of immersion, suggesting a close correlation with moisture uptake, which forms the basis for future modeling. Full article

This paper analyses, as a case study, various balcony glazing arrangements in a typical tourist apartment building on the Mediterranean coast of south-eastern Spain, and their effects on the energy performance. The glazing of terraces has been very common in this type of flat over the last 40 years. The objective is to determine qualitatively and quantitatively how the glazing of terraces in such buildings influences their energy efficiency and indoor thermal comfort, considering the specific characteristics of the dry Mediterranean climate (BShs) within a warm semi-arid climate (BSh). The scientific novelty of the work consists of demonstrating that the installation of glazed enclosures on terraces allows the houses to be heated for free in winter, taking advantage of the greenhouse effect, and allows excess heat to be dissipated in summer by using natural ventilation. The results of the work enable the determination of appropriate terrace glazing solutions to improve the energy efficiency and thermal comfort of the dwelling, obtaining a reduction of more than 58% in annual energy demand and annual energy consumption. The work demonstrates the advantages that glazing systems for terraces can have in improving the energy efficiency of houses by using systems like glass curtains. Full article

Recently, there has been an attempt to implement increasingly significant prefabrication in building construction, since this method is considered to represent an opportunity to reduce impacts in the construction sector. For pitched roofs, there have been relevant developments, such as sandwich panels, asphalt shingles, lightweight roof panels, among others. However, in relation to flat roofs, the advances have been of little relevance and are mainly limited to the improvement of technical characteristics and prefabrication of the construction materials used. The main goal of this article is to demonstrate the possibility of developing new solutions for more sustainable flat roofs in the carbon footprint, and for this purpose a system was developed called ADAPTIVE—Advanced Production System for Sustainable and Productive Roofing Retrofit, which consists of developing a composite solution for the rehabilitation of flat roofs, completely prefabricated and with zero waste, with the aim of increasing energy behaviour, collecting and storing rainwater, and using the roof as a garden leisure space. To obtain the validation results, computerised theoretical modelling was conducted with theoretical assessment of the components and the set of components developed, which allowed us to conclude that the system meets the high hygrothermal, acoustic, and structural requirements. Full article

Signs of wetness in housing are a significant obstacle to the renovation and energy rehabilitation of old and energy-intensive heritage buildings, especially in cold climates. Thus, in order to avoid the numerous possibilities of degradation caused by the moisture transfer phenomena in the building envelope, the a disruptive aeraulic process, which focuses on the ventilation of an air gap between the thermal insulation and the wet wall, has been designed and its assessed. This system avoids the presence of liquid water at the wall surface by maintaining the hygrothermal balance within the wet wall. This enables the mechanical durability of the supporting structure, the absence of biological activity and/or frost and, hence, the durability of the thermal insulation. These issues are investigated through a case study based on a real site. Over a year of measurements, the wet wall was constantly maintained in hygroscopic balance, around 90% RH, guaranteeing the preservation of its mechanical performance, while the insulation layer was kept moisture free. In addition, the proposed model for predicting the appearance and development of biological activity demonstrated its validity, confirming experimental results.These initial results will now lead to the optimization of the aeraulic device, as well as possible use in a summer cooling context to achieve hygrothermal comfort for housing occupants. Full article

Rehabilitation of facades may be carried out with the application of External Thermal Insulation Systems (ETICS). Their main contribution is the increase of the energy efficiency of buildings. In the literature, hygrothermal, impact and fire performance studies have been carried out on several systems with different insulation materials, such as expanded polystyrene, mineral wool and extruded polystyrene foam insulation. Due to the growing concern with the environment, systems are being developed with more sustainable and ecological materials, such as ICB (expanded cork). These type of boards are responsible for a negative impact in global warming potential, significantly improving the environmental benefits of their use. As these systems were recently introduced to the market, applications on site are very recent and their behaviour over time still unknown. In this research, the durability and global performance of more sustainable systems (with ICB) were analysed through an experimental campaign and compared with EPS (expanded polystyrene) systems. The results show that the systems with ICB obtained satisfactory global behaviour comparable with the EPS systems. The ICB sustainable systems analysed stood out in acoustic performance. Full article