Developments in the Built Environment最新文献

The application efficiency of the Dynamic Rotating Latent-Energy-Storage Envelope (DRLESE) system is highly contingent upon dynamic rotation timings. To gain the optimal rotation timings, six different timings were examined by employing the liquid fraction, thermal storage and release, surface temperature and heat flow. The numerical heat transfer method was employed and verified an experiment. Results indicated that the optimal initial rotation occurs in the forenoon, when the inner surface temperature aligns with the sol-air temperature. Subsequently, achieving optimal secondary rotation is possible in the afternoon when the sol-air temperature equals the liquid temperature of PCM (Phase Change Material). Under these optimized initial and secondary rotation timings, the significant enhancements in thermal performance of the DRLESE system were observed. By optimizing rotation timings, indoor effective heat release can reach up to 3182.9 kJ/Day with an effectiveness percentage exceeding 99.99%, and inner surface heat flow was increased by 5.86%–12.26%.

High-performance facades play an important role in achieving Net-Zero goals by 2050. As a facade manufacturing technology, 3D printing offers the opportunity to create site-specific and high-performance building envelopes. In this manuscript, the thermal performance of components fabricated with different Material Extrusion methods is studied experimentally, and the fabrication time is calculated, thereby examining both performance and fabrication viability. More specifically, this manuscript investigates the thermal performance of 3D-printed facades using Hollow-Core 3D printing (HC3DP) and explores the potential of this novel approach in creating thermally insulating, lightweight, and translucent building envelopes. The research compares the thermal resistance of HC3DP specimens to conventional material extrusion methods, such as desktop 3D printers, and granular-based, large-scale pellet extrusion. Different methods are used to determine the thermal resistance of specimens, including the dynamic thermal conductivity measurement for the desktop 3D-printed (3DP) specimens, and the steady-state hot box heat flux meter approach for HC3DP. The results demonstrate that HC3DP enables lower Thermal transmittance (U-value)s at lighter weight and faster printing speed, making it a promising avenue for further research. Additionally, the combination of HC3DP with aerogel is shown to create ultra-lightweight and thermally insulating 3D-printed facade elements. The potential of this new facade technology is also highlighted in comparison with established facade systems. All in all, the manuscript provides insights into the thermal performance of 3D-printed facades at different printing resolutions and emphasizes the importance of printing time and material consumption in determining the most promising 3D printing approach for lightweight and thermally insulating facades.

The overuse of conventional fuels (coal, petroleum products, and gas) for energy generation causes natural resource depletion and global warming. Therefore, the utilization of Renewable Energy Sources (RES) in power systems is seeing rapid growth on a global level, particularly in offshore locations. This work aims to review the progress in developing hybrid RES power systems in offshore environments and optimization methods used for power generation using solar, wind, and wave energy systems. The papers published in peer-reviewed journals were collected from 2000 to 2023. A total of 143 articles were obtained and analyzed. The results demonstrated a rising trend in annual publications about the use of hybrid RES in electricity generation since 2007. The hybrid solar-wind and wind-wave energy systems have received a lot of attention due to technical advancements already developed for the wind energy system. Machine learning techniques, such as genetic algorithms (GA) and particle swarm optimization (PSO), have been extensively utilized in the field of renewable energy systems for tasks such as optimizing unit sizes, determining appropriate unit placements, minimizing costs, and maximizing power output. The methods are preferred due to their less complex structure. However, the practical application, true cost estimation and installation and maintenance studies at offshore locations are poorly developed. Also, the hybrid solar-wave and solar-wind-wave RES systems need further investigations for optimal mixing at the feasibility stage. The current review is the first of its kind, focusing on offshore renewable energy systems only.

This study focused on optimizing the effect of recycled medical glass (RMG) on the performance of high-strength alkali-activated concrete (AAC) at different scales. RMG was incorporated into the AACs to substitute a portion of the precursor, followed by the addition of fine and coarse RMG to replace a portion of the fine and coarse river sand, respectively. Thus, the effects of these variables on compressive strength, splitting strength, and water absorption using the simplex centroid design method were examined. Additionally, freezing-thawing, carbonation resistance, and residual strength at elevated temperatures of AACs were investigated. The experimental results showed that AACs had compressive strengths between 46.8 and 102.0 MPa, tensile strengths between 6.20 and 13.60 MPa, and water absorption between 2.93 and 4.82%. The optimized AACs showed a significant increment in residual strength at high temperatures as compared to the control mixture. The AAC with RMG may provide a compact microstructure with low porosity to enhance carbonation and freeze-thaw resistance. Finally, the outcomes of the ecological evaluation support the usage of RMG in high strength AAC as a sustainable building and construction material.

The cemented lithium feldspar tailings backfill (CLFTB) samples with different fiber types and contents were prepared and subjected to uniaxial compression tests. The results show that glass fiber had the best improvement effect on UCS. With the increase in fiber content, the UCS showed a trend of first increasing and then decreasing, increasing from 1.138 MPa to 2.017 MPa and then decreasing to 1.907 MPa, with the optimal content being 0.6%. The relationship between the strength gain percentage (SGP) and the peak strain gain coefficient γ with fiber content was analyzed. As the fiber content increased, SGP first increased and then decreased while γ gradually increased. Fibers enhanced the ductility, peak load-bearing capacity, and dissipative energy required for the failure of CLFTB. Furthermore, showing greatly enhanced crack resistance in FRCLFTB, evidenced by an increase in the number of fine cracks and a decrease in fragment detachment.

This research explores the use of machine learning to predict the mechanical properties of cementitious materials enhanced with carbon nanotubes (CNTs). Specifically, the study focuses on estimating the elastic modulus and flexural strength of these novel composite materials, with the potential to significantly impact the construction industry. Seven key variables were analyzed including water-to-cement ratio, sand-to-cement ratio, curing age, CNT aspect ratio, CNT content, surfactant-to-CNT ratio, and sonication time. Artificial neural network, support vector regression, and histogram gradient boosting, were used to predict these mechanical properties. Furthermore, a user-friendly formula was extracted from the neural network model. Each model performance was evaluated, revealing the neural network to be the most effective for predicting the elastic modulus. However, the histogram gradient boosting model outperformed all others in predicting flexural strength. These findings highlight the effectiveness of the employed techniques, in accurately predicting the properties of CNT-enhanced cementitious materials. Additionally, extracting formulas from the neural network provides valuable insights into the interplay between input parameters and mechanical properties.

Using slag to produce low-carbon building materials is a sustainable strategy to recycle industrial byproducts. However, with a high clinker substitution rate, the delayed early strength development of slag–cement binders severely limits their applicability in practical engineering. This study investigated the mechanism of action by which aluminum sulfate promotes early strength. Its influence on hydration, microstructure, hydration products, mechanical properties, and CO₂ emissions was investigated. The analysis indicated that aluminum sulfate accelerated the dissolution of C₃S during the induction period, but the precipitation of a large amount of ettringite hindered further hydration. However, this hindering effect decreases as hydration continues. At a 1% dosage, the CO₂ emission per unit strength is the lowest. At a 2% dosage, the early strength can be effectively increased by 38.01%. By comparison, alkali-free aluminum sulfate improves the sustainability and mechanical properties better than an alkaline accelerator (sodium carbonate).

In practice, it is often necessary to add retarders to β-hemihydrate phosphogypsum (β-HPG) to prolong its setting time. In this paper, the effects of modified amino acid (XK) on physical and mechanical properties, hydration characteristics, and microstructure of β-HPG were investigated using various methods including fluidity, setting time, strength, hydration heat, X-ray diffraction (XRD), scanning electron microscope (SEM), mercury intrusion porosimetry (MIP), and X-ray photoelectron spectroscopy (XPS). The findings indicate that the addition of XK enhances the fluidity of β-HPG, and as the content of XK increases, there is an occurrence of prolonged setting time but a concurrent decrease in both the compressive and flexural strength. In addition, the incorporation of XK hampers the hydration process of β-HPG, resulting in a reduction in the hydration exothermic rate. Microscopic analysis reveals that while XK does not alter the final hydration products, it does affect the growth pattern of dihydrate gypsum crystals because of surface adsorption, and specifically, the crystals become short and columnar, with a looser crystal structure. Furthermore, XK leads to larger pores and deterioration of the pore structure of β-HPG.

Combined robotic arms and mobile platforms, mobile construction robots(MCRs) are providing an energizing choice for the digitalization of the building industry. To enhance the comprehension of the research trajectory towards MCR applications and technologies in building construction, we focus on the following aspect: Current representative applications of MCRs in built environments and critical technologies involved. This comprehensive review identified 184 publications in the last 15 years to unravel MCRs in construction applications, scrutinized the crucial technologies involved, and deliberated on challenges and opportunities. Results indicate that MCRs are a growing application field, although the majority are still confined to laboratory settings. To further expand the application of MCR in construction scenarios, this paper proposes corresponding research roadmaps to address the challenges identified. The findings of this review provide an in-depth insight into digital construction and robotics, benefiting researchers and constructors in advancing robotic commercialization.

Several research initiatives across the European Union investigated the application of off-site prefabrication strategies for energy refurbishment of buildings. Although the results obtained, none of these projects offer a solution for reducing the overall cost.

This paper presents the results of the ‘LegnAttivo’ project, an applied research initiative that investigates applications of Mass Customization and Design for Manufacturability to reduce the cost of prefabricated timber-based façades for energy refurbishment. Applying a Design Science Research approach, the research develops a design prototype of timber-based façade elements for the energy refurbishment of the Italian building stock. Relying on a single case study which is a starting point for future generalizations and extensions of the method, results highlight that applications of Design for Manufacturability combined with Computational Design techniques provide effective and efficient solutions, even under extremely customized requirements, and bring to considerable saves, aligned with the ones measured by the scientific community.