Search Results (24)

Buildings account for nearly 40% of global energy consumption, mainly due to the demands of artificial lighting and heating, ventilation, and air-conditioning (HVAC) systems. The integration of semi-transparent photovoltaic (STPV) modules into building envelopes presents a sustainable strategy to lower energy use while simultaneously replacing conventional roofs and façades. However, the performance of STPV systems is strongly influenced by incident solar radiation and building orientation, and elevated surface temperatures can further diminish their efficiency. In this study, the performance of an STPV module was assessed by placing it on a horizontal surface and varying its orientation relative to a 90° reference. To mitigate thermal effects and improve efficiency, a thermal management system incorporating a calcium chloride hexahydrate-based phase change material (PCM) was employed. The PCM was enhanced with nanomaterials—graphene oxide (GO) and aluminum oxide (Al₂O₃)—at weight fractions of 0%, 0.25%, 0.5%, and 1%. The thermophysical properties of the nano-enhanced PCM were analyzed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermal conductivity measurements. Under incident solar radiation of 941 W/m², the electrical efficiencies of the PV, PV–PCM1, and PV–PCM2 modules were measured at 13.75%, 16.84%, and 15.28%, respectively, demonstrating the potential of nano-enhanced PCM to improve STPV performance. Full article

Between 51% and 72% of a bituminous roofing membrane used for structural waterproofing consists of organic material, predominantly bitumen—a derivative of crude oil refining—highlighting the strong dependence of this product on fossil resources. Considering that several tonnes of these membranes must be replaced every 30 to 50 years, substantial potential exists for emission reduction through the establishment of circular material systems. This study investigates this potential by analysing 26 Environmental Product Declarations (EPDs) and life cycle datasets from across Europe covering the period from 2007 to 2023. To ensure comparability, all data were normalised to a declared unit of 1 kg of roofing membrane. The reinforcement layers were categorised into glass and polyester & glass composites, and their differences were examined using Welch’s t-tests. Correlative analyses and linear as well as multiple regression models were then applied to explore relationships between environmental indicators and the shares of organic and mineral mass fractions. The findings reveal that renewable energy sources, although currently representing only a small share of total production energy, provide a major lever for reducing nearly all environmental impact categories. The type of reinforcement layer was also found to influence the demand for fossil resources, both materially and energetically. For most environmental indicators, only multiple regression models can explain at least 30% of the variance based on the proportions of organic and mineral inputs. Overall, the study underscores the crucial importance of high-quality, transparently documented product data for accurately assessing the sustainability of building products. It further demonstrates that substituting fossil energy carriers with renewable sources and optimising material efficiency can substantially reduce environmental burdens, provided that methodological consistency and clarity of indicator definitions are maintained. Full article

Numerous studies have explored the placement of solar panels on the facades or roofs of buildings. This study investigates a new approach to estimating energy generation from transparent, double-sided solar panels integrated into the facade of an existing building, focusing on how the façade’s color influences panel performance. The most significant advantages of integrating double-sided and transparent solar panels on the sides of a building are the natural lighting provided by the sunlight entering the building and the additional energy generated when the radiation returns to the back of the panel. The light beam strikes the front panel, allowing some radiation to pass through the transparent panel to the back side, where it hits the surface. Part of the beam is then reflected toward the rear panel. The fraction of light reflected (albedo) depends on the surface’s color. We first constructed a double-sided, transparent solar panel and integrated it with MATLAB software 2024 code. The model was verified by comparing the simulation results, specifically the I–V and P–V graphs, with data from the manufacturer’s specifications. We conducted an extensive investigation into panels installed on surfaces made of different materials during each installation. This investigation aimed to understand the behavior and performance of the panels when installed on the surfaces of various materials. Full article

Due to limited roof area, photovoltaic (PV) has gradually been installed on other facades of buildings. This research investigates the practical application of a lightweight PV curtain wall. We use EnergyPlus to build a base office building model of fit with a lightweight PV curtain wall. The performance of two typical lightweight PV curtain wall modules is evaluated in five sample Chinese cities of different climates. Simulations were carried out to determine the power generation of faux architectural material PV curtain wall modules (FAM PVCWMs) for the best cavity distance per facade in various cities. We discovered that, in Harbin, Beijing, and Shanghai, the capacity of PV curtain wall modules installed on the south facade is the best, while in Chengdu and Guangzhou, it is the west facade. We also analyzed the power generation and the impact on the indoor environment when installing semi-transparent PV curtain wall modules (ST PVCWMs). Compared with glass, the ST PVCWM’s power generation increased by at least 50%, while the glare index setpoint exceeded time reduced by at least 30.19%. Furthermore, when installed on the north facade of Chengdu and similar cities, it can ensure more than 50% of daylight indexed time and create a more favorable indoor environment. Full article

Due to climate change, population increase, and the urban heat island effect (UHI), the demand for cooling energy, especially in urban areas, has increased and will further increase in the future. Technologies such as radiative cooling offer a sustainable and energy-free solution by using the wavelength ranges of the atmosphere that are transparent to electromagnetic radiation, the so-called atmospheric window (8–13 µm), to emit thermal radiation into the colder (3 K) outer space. Previous publications in the field of textile building cooling have focused on specific fiber structures and textile substrate materials as well as complex multi-layer constructions, which restrict the use for highly scaled outdoor applications. This paper describes the development of a novel substrate-independent coating with spectrally selective radiative properties. By adapting the coating parameters and combining low-emitting and solar-reflective particles, along with a matrix material emitting strongly in the mid-infrared range (MIR), substrate-independent cooling below ambient temperature is achieved. Moreover, the coating is designed to be easily applicable, with a low thickness, to ensure high flexibility and scalability, making it suitable for various applications such as membrane architecture, textile roofs, or tent construction. The results show a median daytime temperature reduction (7 a.m.–7 p.m.) of 2 °C below ambient temperature on a hot summer day. Full article

Amidst the backdrop of rural revitalization and cultural renaissance, there is a surge in the construction demand for replica traditional vernacular dwellings. Traditional cost estimation methods struggle to meet the need for rapid and precise estimation due to the complexity inherent in their construction. To address this challenge, this study aims to enhance the accuracy and efficiency of cost estimation by innovatively developing an Adaptive Self-Explanatory Convolutional Neural Network (ASCNN) model, tailored to meet the specific cost estimation needs of replica traditional vernacular dwellings in the Huizhou region. The ASCNN model employs a Random Forest model to filter key features, inputs these into the CNN for cost estimation, and utilizes Particle Swarm Optimization (PSO) to optimize parameters, thereby improving predictive accuracy. The decision-making process of the model is thoroughly interpreted through SHAP value analysis, ensuring credibility and transparency. During the construction of the ASCNN model, this study collected and analyzed bidding control price data from 98 replica traditional vernacular dwellings. The empirical results demonstrate that the ASCNN model exhibits outstanding predictive performance on the test set, with a Root Mean Square Error (RMSE) of 9828.06 yuan, a Mean Absolute Percentage Error (MAPE) of 0.6%, and a Coefficient of Determination (R²) as high as 0.989, confirming the model’s high predictive accuracy and strong generalization capability. Through SHAP value analysis, this study further identifies key factors such as floor plan layout, roof area, and column material coefficient that are central to cost prediction. The ASCNN model proposed in this study not only significantly improves the accuracy of cost estimation for Huizhou replica traditional vernacular dwellings, but also enhances its transparency and credibility through model interpretation methods, providing a reliable basis for related investment decisions. The findings of this study also offer valuable references and insights for rapid and precise cost estimation of replica buildings in other regions worldwide. Full article

The natural ventilation of buildings can be achieved effectively with solar chimneys, which are classified into wall, roof, and combined wall–roof configurations. Among the combined systems investigated in the literature, vertical wall–horizontal roof solar chimneys have not been evaluated thoroughly. This study investigates the performance of a combined vertical wall–horizontal roof solar chimney numerically. A two-dimensional Computational Fluid Dynamics (CFD) model is employed to examine the flow and thermal characteristics under various influencing factors relating to the chimney’s geometry, the flow resistance caused by the bend connecting the vertical and horizontal portions, the reverse flow at the outlet, and the location of the heat source. Compared to a vertical wall chimney at the same cavity height, the combined system always had a lower flow rate but had a higher thermal efficiency at some length-to-total-height ratios. Heating the upper walls induced higher flow rates but lower thermal efficiency. Particularly, the effect of the bend on the flow rate was more important than that of the reverse flow at the outlet. These results imply that a combined chimney is preferred over a vertical one for heating applications, wherein the combined chimney should have transparent upper walls. Full article

An environmentally conscious architectural design of a railway station can have a substantial influence on government spending. Nevertheless, an extensive collection of guidelines for using sustainable design principles in the construction of a railway station can provide several advantages. The goal is to review design visions for railway stations in Thailand, as reflected in student theses and government proposals, from 1983 to 2022 for sustainable design aspects in tropical climates. We perform an analysis of architectural design aspects including service areas, shape, entrances, roofing, style, and development in order to uncover design trends and possible areas that may be enhanced. Station designs are mostly characterized by curved and gable roofs, with 3D curved buildings being the next most common feature. High speed rail (HSR) stations stress local cultural elements in their major entrances while also improving passenger flow. Public buildings frequently employ curved or gabled porticos to achieve a majestic look. Although university theses place a high importance on conceptual design and functionality, it is essential to also consider cost-effectiveness. Key design considerations for future railway stations are transparency, connection, efficient mobility, and cost–time efficiency. The research uncovers deficiencies in user-centered design for thermal comfort and inclusiveness (design-for-all) in Thailand’s tropical environment. Addressing these aspects is critical for future sustainable railway station design evaluations. 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

Thin, flat textile roofing offers negligible heat insulation. In warm areas, such roofing membranes are therefore equipped with metallized surfaces to reflect solar heat radiation, thus reducing the warming inside a textile building. Heat reflection effects achieved by metallic coatings are always accompanied by shading effects as the metals are non-transparent for visible light (VIS). Transparent conductive oxides (TCOs) are transparent for VIS and are able to reflect heat radiation in the infrared. TCOs are, e.g., widely used in the display industry. To achieve the perfect coatings needed for electronic devices, these are commonly applied using costly vacuum processes at high temperatures. Vacuum processes, on account of the high costs involved and high processing temperatures, are obstructive for an application involving textiles. Accepting that heat-reflecting textile membranes demand less perfect coatings, a wet chemical approach has been followed here when producing transparent heat-reflecting coatings. Commercially available TCOs were employed as colloidal dispersions or nanopowders to prepare sol–gel-based coating systems. Such coatings were applied to textile membranes as used for architectural textiles using simple coating techniques and at moderate curing temperatures not exceeding 130 °C. The coatings achieved about 90% transmission in the VIS spectrum and reduced near-infrared transmission (at about 2.5 µm) to nearly zero while reflecting up to 25% of that radiation. Up to 35% reflection has been realized in the far infrared, and emissivity values down to ε = 0.5777 have been measured. Full article

Perovskite solar cells (PSCs) are emerging photovoltaics (PVs) with promising optoelectronic characteristics. PSCs can be semitransparent (ST), which is beneficial in many innovative applications, including building-integrated photovoltaics (BIPVs). While PSCs exhibit excellent performance potential, enhancements in their stability and scalable manufacturing are required before they can be widely deployed. This work evaluates the real-world effectiveness of using PSCs in BIPVs to accelerate the development progress toward practical implementation. Given the present constraints on PSC module size and efficiency, bus stop shelters are selected for investigation in this work, as they provide a suitably scaled application representing a realistic near-term test case for early-stage research and engineering. An energy-harvesting system for a bus stop shelter in Astana, Kazakhstan, demonstrates the potential performance evaluation platform that can be used for perovskite solar cell modules (PSCMs) in BIPVs. The system includes maximum power point tracking (MPPT) and charge controllers, which can supply PSCM energy to the electronic load. Based on our design, the bus stop shelter has non-transparent and ST PSCMs on the roof and sides, respectively. May (best-case) and December (worst-case) scenarios are considered. According to the results, the PSCMs-equipped bus stop shelter can generate sufficient daily energy for load even in a worst-case scenario. Full article

The building envelope provides thermal comfort, an excellent visual view, and sunlight for the occupants. It consists of two parts: (i) an opaque (non-transparent) part (e.g., walls and roofs) and (ii) a transparent part (e.g., windows, curtain walls, and skylight devices). Recently, the use of fully-glazed facades, especially in large cities, has increased due to their aesthetical and structural advantages. This has led this study to review the performance of the currently passive smart glazing technologies. Phase Change Materials (PCMs) as latent energy storage material is the focus of this review, as well as other individual and combined techniques, including shading systems, solar cells (photovoltaic), and chromogenic (thermotropic and thermochromic) materials. PCM-integrated glazing systems have been extensively studied and rapidly developed over the past several decades from the standpoint of unique system designs, such as passive, active, and passive/active mixed designs, intelligent management, and sophisticated controls. In the academic literature, numerous studies on PCM-integrated building envelopes have been conducted, but a comprehensive review of PCM-integrated GUs combined with other passive and active techniques using dialectical analysis and comparing the climatic conditions of each study using Köppen-Geiger climate classification climate classification has been performed only rarely. Consequently, the primary objective of this study is to reduce this discrepancy for all types of glazing, excluding glazed roofs. This review article also contains literature tables as well as highlights, limitations, and further research suggestions at the end of each subsection. Full article

In buildings with ambitious energy goals or limited roof areas for on-site energy generation, building-integrated solar thermal collectors are one of the main strategies to provide on-site renewable energy to the built environment. In addition, designing large glazing facades is a challenge to achieving the goal of zero-energy buildings due to the thermal load produced by standard double or triple glazing. This research shows that Water Flow Glazing (WFG) can produce domestic hot water as a building-integrated solar thermal collector by flowing water through the chamber between glass panes and can help reduce thermal loads through facades. In this article, the solar collector’s efficiency was defined according to the UNE-EN 12975-2 standard and then applied to the Water Flow Glazing. As a result, the transparent Water Flow Glazing’s optical efficiency η₀ varies from 0.648 to 0.742, whereas the thermal loss coefficient a₁ ranges from 9.51 to 4.16. Those values are like those of commercial plate collectors. Afterward, the model to predict the efficiency of WFG was tested in an existing facility by calculating the Normalized Root Mean Square Error (NRMSE) to assess the deviations between the simulation and measured values. Using building-integrated solar collectors can improve the integration of renewable energies in facades and roofs but also increase the uncertainties that affect their efficiencies, such as internal heat loads and heating, cooling, and ventilation systems. Therefore, testing existing facilities can help understand the impact of these technologies in the Zero Energy Building paradigm. Full article

The classroom space located in the attic of an old building is the subject of this study. The building was renovated and new spaces were created in the unused attic to expand classrooms. The original space under the sloping roof was not used because its internal headroom was not suitable. During the restoration, the entire original truss was raised gradually (in parts) by 1.2 m. This created a space with an entire area that can be used for classrooms. Continuous strips of vertical windows measuring 860/600 mm were installed in the space which enable a visual connection between the interior space and the exterior. At roof level, there are also two rows of skylights above each other which ensure enough daylight is present but create unpleasant overheating in the summer. The purpose of this study is to find a way to optimize the shading of transparent surfaces and the heat accumulation of building structures in order to achieve suitable interior conditions in the attic. This task was achieved by shading the windows in the attic. Shaded windows decrease illumination by 82% compared to unshaded ones. The percentage decrease in illumination is more significant than the decrease in the maximum temperature due to overheating. Additionally, the maximum temperature in the attic drops by only 31% if vertical and skylight windows are shaded with external blinds compared to unshaded windows. The minimum air temperature reached in the attic also drops by 26%. In order for users in the attic space to feel comfortable, it is necessary to use HVAC equipment in addition to the design of suitably built structures and window shading. Full article

Solar energy is a renewable, green, clean, and universal resource that has great potential in rural areas. Combining solar heating technology with building design to increase indoor thermal comfort in winter is an effective energy-saving and environmentally friendly approach. The factors affecting solar building heating mainly include two aspects; one is the lighting area of the building, and the other is the storage of building materials. By increasing the lighting area and using materials with good heat preservation and storage performance, the indoor temperature in winter can be effectively increased, and the heating time can be prolonged, thus decreasing the energy requirements of the building. In this paper, traditional houses in cold winter areas are selected as the research object, and a roof solar heating storage system is proposed. The method is to transform the opaque roof of the traditional houses into a transparent glass roof, and the thermal insulation and heat storage material HDPE is installed in the attic floorboards. The working principle of this system is to increase the amount of indoor solar radiation to raise the indoor temperature and make use of the thermal insulation performance of heat storage materials to prolong the indoor heating time. Through ANSYS software simulation, the heat transfer process, heat transfer mode, and temperature change of the system are analyzed, and the energy saving of the system is analyzed. The system can effectively raise the indoor temperature and has good energy-saving performance. The indoor temperature is raised by 5.8 °C, and the annual heat load of the building is reduced by 1361.92 kW·h, with a reduction rate of 25.02%. Full article