Search Results (145)

Rammed earth (RE), a traditional material aligned with circular economy (CE) principles, has been gaining renewed interest in contemporary construction due to its low environmental impact and compatibility with sustainable building strategies. Though not a modern invention, it is being reintroduced in response to the increasingly strict European Union (EU) regulations on carbon footprint, life cycle performance, and thermal efficiency. RE walls offer multiple benefits, including humidity regulation, thermal mass, plasticity, and structural strength. This study also draws attention to their often-overlooked ability to mitigate indoor overheating. To preserve these advantages while enhancing thermal performance, this study explores insulation strategies that maintain the vapor-permeable nature of RE walls. A parametric analysis using Delphin 6.1 software was conducted to simulate heat and moisture transfer in two main configurations: (a) a ventilated system insulated with mineral wool (MW), wood wool (WW), hemp shives (HS), and cellulose fiber (CF), protected by a jute mat wind barrier and finished with wooden cladding; (b) a closed system using MW and WW panels finished with lime plaster. In both cases, clay plaster was applied on the interior side. The results reveal distinct hygrothermal behavior among the insulation types and confirm the potential of natural, low-processed materials to support thermal comfort, moisture buffering, and the alignment with CE objectives in energy-efficient construction. Full article

This review article focuses on the long-term durability challenges associated with bamboo fiber-reinforced polymer composites when subjected to various environmental aging conditions such as water immersion, hygrothermal fluctuations, ultraviolet (UV) radiation, soil burial, and refrigerated storage. The primary issue addressed is the degradation of mechanical and structural performance of bamboo fiber-reinforced polymer composites due to moisture absorption, fiber swelling, and fiber–matrix interface deterioration. To mitigate these aging effects, the study evaluates and compares multiple strategies, including chemical and physical fiber surface treatments, filler additions, and fiber hybridization, which aim to enhance moisture resistance and mechanical stability. These composites are relevant in automotive interiors, construction panels, building insulation, and consumer goods due to their eco-friendly nature and potential to replace conventional synthetic composites. This review is necessary to consolidate current knowledge, identify effective enhancement approaches, and guide the development of environmentally resilient bamboo fiber-reinforced polymer composites for real-world applications. Full article

The construction sector presently consumes about 40% of global energy and generates 36% of CO₂ emissions, making facade retrofits a priority for decarbonising buildings. This review clarifies how ventilated facades (VFs), wall assemblies that interpose a ventilated air cavity between outer cladding and the insulated structure, address that challenge. First, the paper categorises VFs by structural configuration, ventilation strategy and functional control into four principal families: double-skin, rainscreen, hybrid/adaptive and active–passive systems, with further extensions such as BIPV, PCM and green-wall integrations that couple energy generation or storage with envelope performance. Heat-transfer analysis shows that the cavity interrupts conductive paths, promotes buoyancy- or wind-driven convection, and curtails radiative exchange. Key design parameters, including cavity depth, vent-area ratio, airflow velocity and surface emissivity, govern this balance, while hybrid ventilation offers the most excellent peak-load mitigation with modest energy input. A synthesis of simulation and field studies indicates that properly detailed VFs reduce envelope cooling loads by 20–55% across diverse climates and cut winter heating demand by 10–20% when vents are seasonally managed or coupled with heat-recovery devices. These thermal benefits translate into steadier interior surface temperatures, lower radiant asymmetry and fewer drafts, thereby expanding the hours occupants remain within comfort bands without mechanical conditioning. Climate-responsive guidance emerges in tropical and arid regions, favouring highly ventilated, low-absorptance cladding; temperate and continental zones gain from adaptive vents, movable insulation or PCM layers; multi-skin adaptive facades promise balanced year-round savings by re-configuring in real time. Overall, the review demonstrates that VFs constitute a versatile, passive-plus platform for low-carbon buildings, simultaneously enhancing energy efficiency, durability and indoor comfort. Future advances in smart controls, bio-based materials and integrated energy-recovery systems are poised to unlock further performance gains and accelerate the sector’s transition to net-zero. Emerging multifunctional materials such as phase-change composites, nanostructured coatings, and perovskite-integrated systems also show promise in enhancing facade adaptability and energy responsiveness. Full article

A wave of energy efficiency-focused activity has spread across Europe in recent years, with ambitious goals for improving the energy performance of existing buildings through various directives. Among these existing buildings, there are older structures with heritage-protected facades. Some of the protected facades consist of timber plank frame walls, which were common in Norway in the 19th and early 20th centuries. Internal insulation is an option for increasing the energy efficiency of such walls while preserving their protected facades. However, this approach alters the moisture performance of the wall and introduces a potential risk for mould growth, which must be assessed. To better understand the performance of these walls, the $s_d$ values of traditional types of building paper have been tested, as timber plank frame walls comprise vertical planks covered in building paper. In addition, the risk of mould growth in timber plank frame walls has been evaluated using the one-dimensional simulation tool WUFI^® Pro by modelling the wall with internal retrofitting and varying input parameters. The types of building paper used have a wide range of vapour resistance values (diffusion-equivalent air layer thicknesses, $s_d$ values), which range from 0.008 m to 5.293 m. Adding 50 mm of interior insulation generally resulted in a low risk of mould growth, except in cases involving the use of a moisture-adaptive vapour barrier (MAVB). The MAVB did not result in an acceptable mould growth risk in any of the tested scenarios. Full article

In the context of intensified construction and stricter requirements for the energy efficiency of buildings, the use of thermal insulation materials and technologies is becoming particularly important. One promising area in this field is the use of thermal insulation mixtures, which are versatile, adaptable, and highly reliable in operation. Mixtures based on fillers with a porous structure and materials that impart thermal insulation properties, which provide higher thermal insulation properties, are of great interest. However, the development of dry thermal insulation mixtures is hampered by insufficient study of their physical, mechanical, and operational characteristics. This article presents the results of research work on the development and study of dry building thermal insulation mixtures. A distinctive feature of the work is the creation of a composition of dry building thermal insulation mixtures based on local raw materials, such as diatomite, its thermal modification at a temperature of 900 °C, the use of expanded perlite sand, lime, and Portland cement. Research into the properties of modified diatomite has shown that its surface after thermal treatment differs from the surface of unburned diatomite in that it becomes more active and has a 3–4 times higher increase in strength. Modified diatomite and expanded perlite sand have low thermal conductivity, and this property was used in the creation of building thermal insulation mixtures, which was confirmed by research, as the thermal conductivity coefficient ranged from 0.128 to 0.152 W/m °C. The developed dry thermal insulation lime–cement mixture is intended for both interior and exterior finishing works, which is confirmed by the results obtained for determining the frost resistance of the solution and the frost resistance of the contact zone, and corresponds to the F35 grade and has a strength of up to 3.59 MPa. Full article

The significant waste generated by construction has increased interest in sustainable solutions, including prefabricated interior partition panels. Although different types of alternative panels have been proposed, their performance as interior partitions remains underexplored in systematic comparative studies. To narrow this knowledge gap, this paper presents a comprehensive evaluation and classification of drywall, OSB (Oriented Strand Board), cement–wood, and honeycomb panels, regarding physical, mechanical, microstructural, thermal, acoustic, and combustibility characteristics, in addition to conducting a cost evaluation. The results indicated that the OSB panels exhibited superior results for interior partition applications, showing notable advantages in physical strength, mechanical performance, and thermal insulation, while offering acoustic properties comparable to those of drywall panels. Nevertheless, OSB panels showed lower fire resistance and were associated with the highest cost among the materials analyzed in the present research. Drywall panels, on the other hand, provided the most favorable fire resistance but exhibited the least effective thermal insulation. The findings also indicated that both wood–cement and honeycomb panels require further improvements in their manufacturing processes to meet performance standards suitable for interior partition. Full article

Prefabricated components inevitably generate numerous assembly joints during installation, with each 1 mm increase in joint width correlating to a 15–20% elevation in the annual occurrence frequency of the frost formation risk. In the Inner Mongolia Region, the water migration at wall connection interfaces during winter significantly exacerbates freeze–thaw damage due to persistent thermal gradients. A coupled heat–moisture transfer model incorporating gas–liquid–solid phase transitions was developed, with the liquid moisture content and temperature gradient as dual driving forces. A validation against internationally recognized BS EN 15026:2007 benchmark cases confirmed the model robustness. The prefabricated sandwich insulation walls reconstructed with region-specific volcanic ash materials underwent a comparative evaluation of temperature and relative humidity distributions under varied winter conditions. Furthermore, we analyze and assess the potential for freezing at connection points and identify the specific areas at risk. Synergistic effects between assembly gaps and indoor–outdoor environmental interactions on wall performance degradation were systematically assessed. The results indicated that, across all working conditions, both the temperature and relative humidity at each wall measurement point underwent periodic variations influenced by the outdoor environment. These fluctuations decreased in amplitude from the exterior to the interior, accompanied by a noticeable delay effect. Specifically, at Section 2, the wall temperatures at points B2–B8 were higher compared to those at A2–A8 of Section 1. The relative humidity gradient remained relatively stable at each measurement point, while the temperature fluctuation amplitude was smaller by 2.58 ± 0.3 °C compared to Section 1. Under subfreezing conditions, Section 1 demonstrates a marked reduction in relative humidity (Cases 1-3 and 2-3) compared to reference cases, which is indicative of internal ice crystallization. Conversely, Section 2 maintains higher relative humidity values under identical therma. These findings suggest that prefabricated building joints significantly impact indoor and outdoor wall temperatures, potentially increasing the indoor heat loss and accelerating temperature transfer during winter. Full article

The front wall acoustic package system plays a crucial role in automotive design, and its performance directly affects the quality and comfort of the interior noise. In response to the limitations of traditional experimental and simulation methods in terms of accuracy and efficiency, this paper proposes a convolutional neural network (AFWL-CNN) based on adaptive weighted feature learning. Using a data-driven method, the sound insulation performance of the entire vehicle’s front wall acoustic package system was predicted and analyzed based on the original parameters of the front wall acoustic package components, thereby effectively avoiding the shortcomings of traditional TPA and CAE methods. Compared to the traditional CNN model (RMSE = 0.042, MAE = 3.89 dB, I-TIME = 13.67 s), the RMSE of the proposed AFWL-CNN model was optimized to 0.031 (approximately 26.19% improvement), the mean absolute error (MAE) was reduced to 2.84 dB (approximately 26.99% improvement), and the inference time (I-TIME) increased to 17.16 s (approximately 25.53% increase). Although the inference time of the AFWL-CNN model increased by 25.53% compared to the CNN model, it achieved a more significant improvement in prediction accuracy, demonstrating a reasonable trade-off between efficiency and accuracy. Compared to AFWL-LSTM (RMSE = 0.039, MAE = 3.35 dB, I-TIME = 19.81 s), LSTM (RMSE = 0.044, MAE = 4.07 dB, I-TIME = 16.71 s), and CNN–Transformer (RMSE = 0.040, MAE = 3.74 dB, I-TIME = 19.55 s) models, the AFWL-CNN model demonstrated the highest prediction accuracy among the five models. Furthermore, the proposed method was verified using the front wall acoustic package data of a new car model, and the results showed the effectiveness and reliability of this method in predicting the acoustic package performance of the front wall system. This study provides a powerful tool for fast and accurate performance prediction of automotive front acoustic packages, significantly improving design efficiency and providing a data-driven framework that can be used to solve other vehicle noise problems. Full article

As energy-efficient buildings become central to climate change mitigation, the opportunity for interior and interstitial moisture accumulation and mould growth can increase. This study investigated the potential simulation-based mould growth risks associated with the current generation of insulated low-rise timber framed external wall systems within southeastern Australia. More than 8000 hygrothermal and bio-hygrothermal simulations were completed to evaluate seasonal moisture patterns and calculate mould growth potential for nine typical external wall systems. Results reveal that the combination of increased thermal insulation and air-tightness measures between the 2010 and 2022 specified building envelope energy efficiency regulations further increased predicted Mould Index values, particularly in cool-temperate climates. This was in part due to insufficient moisture management requirements, like an air space between the cladding and the weather resistive layer and/or the low-water vapour permeability of exterior weather resistive pliable membranes. By contrast, warmer temperate climates and drier cool-temperate climates exhibit consistently lower calculated Mould Index values. Despite the 2022 requirement for a greater water vapour-permeance of exterior pliable membranes, the external walls systems explored in this research had a higher calculated Mould Index than the 2010 regulatory compliant external wall systems. Lower air change rates significantly increased calculated interstitial mould growth risk, while the use of interior vapour control membranes proved effective in its mitigation for most external wall systems. The addition of ventilated cavity in combination with either or both an interior vapour control membrane and a highly vapour-permeable exterior pliable membranes further reduced risk. The findings underscore the need for tailored, climate-responsive design interventions to minimise surface and interstitial mould growth risk and building durability, whilst achieving high performance external wall systems. Full article

Natural and liquefied petroleum gases are widely used in industrial heat treatment. However, the rising cost of gas, combined with increased demand, has significantly impacted production costs and the environment. The annealing process typically relies on natural or liquefied petroleum gases as the primary heat source. In this study, we aimed to investigate the use of biomass fuel as a replacement for fossil fuels and to evaluate the mechanical properties and microstructure of wire rod steel after annealing using indirect heat from a gasifier. We experimented to examine the effects of annealing temperatures of 650 °C, 700 °C (below the critical temperature Ac1), and 750 °C (above Ac1 but below the upper temperature Ac3). The batch furnace, made of stainless steel, was modified from a traditional wire annealing furnace that originally used CNG and LPG gas burners. It was adapted into a wire annealing furnace connected to a cross-draft gasifier. The furnace’s interior was designed with spiral cooling fins to minimize energy consumption and shorten annealing time. Additionally, it was modified to use biomass as a substitute fuel, reducing environmental pollution. The furnace was coated with thermal insulation, and the biomass gasifier stove was a cross-draft device with primary air feeding at 20 m³/h and secondary air supplied at a constant flow rate of 32 m³/h, 36 m³/h, or 40 m³/h. As a fuel source, we used eucalyptus. The mechanical properties of wire rod steel were measured in terms of tensile strength and torsion, following the TIS 138-2562 standard. This standard specifies that the tensile strength must be at least 260 MPa. Regarding torsion, the TIS 138-2562 requirements state that the wire must withstand at least 75 rounds of twisting without breaking. Our results showed that after annealing at 650 °C, 700 °C, or 750 °C, with a soaking time of 30 min and subsequent cooling in the furnace at natural temperature for 24 h, the tensile strength values were 494.82, 430.87, and 381.33 MPa, respectively. The torsion values were 126.92, 125.8, and 125.76 rounds, respectively. Additionally, ferrite grain size increased with annealing temperature, reaching a maximum of 750 °C. The total annealing duration for each batch was 2 h and 40 min at 650 °C, 2 h and 10 min at 700 °C, and 2 h at 750 °C. Full article

Wineries require a significant energy demand for cooling interior spaces. As a result, designing energy-efficient winery buildings has become a crucial concern for winemaking countries. The objective of this study was to evaluate six winery building models with bioclimatic designs, located in the Guadalupe Valley, Baja California, using data on thermal performances (indoor temperature and relative humidity) and energy consumption obtained through dynamic thermal simulation. A baseline winery building model was developed and then enhanced with bioclimatic strategies: a semi-buried building; an underground cellar; an underground cellar with the variants of a green roof, double roof, shaded walls, and polyurethane insulation. The last solution entailed the requirement of a reduction in cooling in the warm season by 98 MWh, followed by the one with a green roof, corresponding to 94 MWh. This study provides valuable insights into the effectiveness of different architectural approaches, offering guidelines for the design of functional buildings for wine production, besides presenting energy-efficient solutions for wineries tailored to the climatic conditions of the study region. These findings highlight the importance of a function-based and energy-efficient architectural design in the winemaking industry, which leads to the definition of buildings with a compact arrangement of the functional spaces and a fruitful integration of the landscape through a wise adoption of underground solutions. Full article

The external walls of a building represent the interface between the interior and exterior environments. Insulating external walls represents the most cost-effective means of ensuring indoor comfort. Despite the prevailing assumption that insulation will increase the cost of the building, this study has demonstrated that this is not the case. Notwithstanding the increase in investment costs, the application of insulation to the external walls has been demonstrated to result in a reduction in fuel consumption and operating costs. In accordance with TS 825, there are five distinct degree-day zones, with the requisite heat loads in these zones exhibiting variability. Accordingly, a cost-based methodology is required to ascertain the optimal insulation thicknesses for the various degree-day zones. In this study, the gains to be obtained in the case of using three different insulation materials for five different wall types to be used in the buildings to be built instead of the buildings destroyed in the earthquake in Turkey in 2023 were analyzed. Samples from three degree-day zones affected by earthquakes were assessed for insulation, wall structures, and fuel types. The study assesses optimum insulation thickness, investment cost, annual fuel savings, annual economic benefits, and investment payback period. Full article

Composite phase-change materials (PCMs) exhibit significant potential for enhancing the thermal performance of building walls. However, previous studies have generally lacked detailed investigations of the performance of PCM-integrated walls under cold climate conditions. Therefore, in order to evaluate the thermal performance and wall adaptability of hollow bricks with composite PCMs in cold climates, a brick model was created by filling the hollow bricks with PCMs. Then a comparative test was conducted between the PCM-filled bricks and the conventional non-PCM-filled hollow bricks. The comparative experimental method and the thermal performance index evaluation method resulted in the following: (1) Compared with conventional hollow bricks, PCM-filled bricks showed an increase of approximately 0.99 °C in inner surface temperature and 3.85 °C in midsection temperature. This demonstrates that PCM-filled bricks can retard the rate of temperature drop, significantly enhancing the insulation performance of walls. This improvement contributes to enhance indoor thermal comfort and reduce energy consumption. (2) The temperature difference between the interior and exterior surfaces of the non-PCM-filled hollow bricks is 23.54 °C, which is 5.62 °C higher than that of the PCM-filled bricks. This indicates that bricks filled with PCMs possess superior heat storage capacity, effectively reducing indoor heat loss, which aligns with the principles of green building design. (3) Compared with the conventional non-PCM-filled hollow bricks, the heat flow on the inner surface of the PCM-filled bricks is significantly lower, with the average heat flow reduced by 8.57 W/m². This suggests the ability of bricks filled with PCMs to moderate heat flux fluctuations through a “peak-shaving and valley-filling” effect, contributing to reduced energy consumption and enhanced occupant thermal comfort. Full article

This study focused on examining the reinforcement of milkweed fibers in polylactic acid (PLA) bio-composites used for dashboards in car interiors. Milkweed fiber is a natural fiber with a hollow structure that provides tremendous thermal insulation and noise resistance properties. Firstly, the milkweed fibers were blended with PLA fibers in a weight ratio of 75:25 using an air-laying process. Then, several layers of nonwoven material were compressed in a hydraulic press to obtain bio-composites. Finally, three bio-composites were obtained with different numbers of layers. The density, microstructure, thermal conductivity, sound transmission loss (STL), mechanical properties, dynamic mechanical analysis (DMA), and contact angles of the bio-composites were evaluated. The microstructure analysis revealed that some milkweed fibers collapsed due to the high-pressure molding process, which does not affect the bio-composite properties. The bio-composite with a higher number of nonwoven layers presented a poor interface between PLA and milkweed fibers, thus making it less homogeneous. This bio-composite showed a decrease of 5% in thermal conductivity values and a 19% increase in STL values. In addition, it exhibited a 160% increase in specific flexural strength and a 335% increase in specific flexural modulus compared to samples with a lower number of nonwoven layers. Therefore, it offers the best mechanical-property-to-density ratio, with values that conform to the specifications required for automotive dashboards. Full article

The KREIS-Haus, an inhabited living lab in Switzerland, serves as a demonstrator of the implementation of sustainable and circular building practices. Addressing the environmental impacts associated with construction, operation, and deconstruction, this study presents an innovative systematic design concept that synthesizes principles of the circular economy, Cradle-to-Cradle design, and ecological engineering. The design process was applied to the KREIS-Haus as a lighthouse project, combining theoretical frameworks with real-word application to derive actionable insights. The novelty of the KREIS-Haus lies in the holistic integration of circular and sustainable concepts within a compact footprint, realized in a real-life, publicly accessible living lab. Its design maximizes resource efficiency by incorporating locally sourced materials, modular construction techniques, and flexible interior features, which allow for easy disassembly and reuse. At the heart of its circular design is the multifunctional conservatory, which provides heat and sound insulation, generates solar power, and expands the living space. Additionally, it supports plant cultivation and enables the reuse of treated wastewater and nutrients, as part of the off-grid water and nutrient management system to reduce reliance on external resources. The principles of solar architecture further minimize the building’s energy demands. Key insights from the design and construction process highlight the challenges of navigating conflicting goals, the importance of partner alignment, and considerations for scaling these concepts to larger developments. While technical challenges may arise, addressing systemic barriers will be essential for advancing sustainable and circular building practices on a broader scale. Full article