Search Results (221)

Urban areas are responsible for most of Europe’s energy demand and emissions and urgently require building retrofits to meet climate neutrality goals. This study evaluates the energy efficiency potential of three public school buildings in western Macedonia, Greece—a cold-climate region with high heating needs. The buildings, constructed between 1986 and 2003, exhibited poor insulation, outdated electromechanical systems, and inefficient lighting, resulting in high oil consumption and low energy ratings. A robust methodology is applied, combining detailed on-site energy audits, thermophysical diagnostics based on U-value calculations, and a techno-economic assessment utilizing Net Present Value (NPV), Internal Rate of Return (IRR), and SWOT analysis. The study evaluates a series of retrofit measures, including ceiling insulation, high-efficiency lighting replacements, and boiler modernization, against both technical performance criteria and financial viability. Results indicate that ceiling insulation and lighting system upgrades yield positive economic returns, while wall and floor insulation measures remain financially unattractive without external subsidies. The findings are further validated through sensitivity analysis and policy scenario modeling, revealing how targeted investments, especially when supported by public funding schemes, can maximize energy savings and emissions reductions. The study concludes that selective implementation of cost-effective measures, supported by public grants, can achieve energy targets, improve indoor environments, and serve as a replicable model of targeted retrofits across the region, though reliance on external funding and high upfront costs pose challenges. Full article

Cement is widely used as the primary binder in concrete; however, growing environmental concerns and the rapid expansion of the construction industry have highlighted the need for more sustainable alternatives. Geopolymers have emerged as promising eco-friendly binders due to their lower carbon footprint and potential to utilize industrial byproducts. Geopolymer mortar, like other cementitious substances, exhibits brittleness and tensile weakness. Basalt fibers serve as fracture-bridging reinforcements, enhancing flexural and tensile strength by redistributing loads and postponing crack growth. Basalt fibers enhance the energy absorption capacity of the mortar, rendering it less susceptible to abrupt collapse. Basalt fibers have thermal stability up to about 800–1000 °C, rendering them appropriate for geopolymer mortars designed for fire-resistant or high-temperature applications. They assist in preserving structural integrity during heat exposure. Fibers mitigate early-age microcracks resulting from shrinkage, drying, or heat gradients. This results in a more compact and resilient microstructure. Using basalt fibers improves surface abrasion and impact resistance, which is advantageous for industrial flooring or infrastructure applications. Basalt fibers originate from natural volcanic rock, are non-toxic, and possess a minimal ecological imprint, consistent with the sustainability objectives of geopolymer applications. This study investigates the mechanical and thermal performance of a geopolymer mortar composed of metakaolin and red mud as binders, with basalt powder and limestone powder replacing traditional sand. The primary objective was to evaluate the effect of basalt fiber incorporation at varying contents (0.4%, 0.8%, and 1.2% by weight) on the durability and strength of the mortar. Eight different mortar mixes were activated using sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) solutions. Mechanical properties, including compressive strength, flexural strength, and ultrasonic pulse velocity (UPV), were tested 7 and 28 days before and after exposure to elevated temperatures (200, 400, 600, and 800 °C). The results indicated that basalt fiber significantly enhanced the performance of the geopolymer mortar, particularly at a content of 1.2%. Specimens with 1.2% fiber showed up to 20% improvement in compressive strength and 40% in flexural strength after thermal exposure, attributed to the fiber’s role in microcrack bridging and structural densification. Subsequent research should concentrate on refining fiber type, dose, and dispersion techniques to improve mechanical performance and durability. Examinations of microstructural behavior, long-term durability under environmental settings, and performance following high-temperature exposure are crucial. Furthermore, investigations into hybrid fiber systems, extensive structural applications, and life-cycle evaluations will inform the practical and sustainable implementation in the buildings. Full article

The current climate and energy crises demand innovative approaches to operating buildings more sustainably. HVAC systems, which significantly contribute to a building’s energy consumption, have been a major focus of research aimed at improving operational efficiency. However, a critical factor often overlooked is the seasonal and hourly variation in solar radiation and the resulting solar heat gain, which heats specific rooms differently depending on their orientation, type, and location within the building. This study proposes a simulation-based strategy to reduce HVAC energy use in hotels by allocating guests to rooms with more favorable thermal characteristics depending on the season. A high-resolution building energy model (BEM) was developed to represent a real 17-floor hotel tower in Madrid, incorporating detailed geometry and surrounding shading context. The model includes 439 internal thermal zones and simulates solar radiation using EnergyPlus’ Radiance module. The simulation results revealed large room-by-room differences in thermal energy demand. When applying an energetically optimized guest allocation strategy based on these simulations and using real occupancy data, potential reductions in HVAC energy demand were estimated to reach around 6% during summer and up to 20% in winter. These findings demonstrate that data-driven guest allocation, informed by physics-based building simulations, can provide substantial energy savings without requiring physical renovations or equipment upgrades, offering a promising approach for more sustainable hotel operation. Full article

Decarbonisation in hot climates demands innovative cooling solutions that minimise environmental impact through renewable energy integration and advanced system optimisation. This study investigates the energetic and economic feasibility of a thermo-mechanical vapour compression (TMVC) cooling system that integrates a conventional vapour compression cycle with an ejector and a thermally driven second-stage compressor powered by solar-heated water from evacuated flat-plate collectors. The system is designed to reduce mechanical compressor work and enhance cooling performance in hot climates. A comprehensive 4E (energy, exergy, economic, and environmental) analysis is conducted for a multi-story residential building in Baghdad, Iraq, with a total floor area of approximately 8000 m² and a peak cooling demand of 521.75 kW. Numerical simulations were conducted to evaluate various configurations of solar collector areas, thermal storage tank volumes, and collector mass flow rate, aiming to identify the most energy-efficient combinations. These optimal configurations were then assessed from economic and environmental perspectives. Among them, the system featuring a 600 m² collector area and a 34 m³ storage tank was selected as the optimal case based on its superior electricity savings and energy performance. Specifically, this configuration achieved a 28.28% improvement in the coefficient of performance, a 22.05% reduction in energy consumption, and an average of 15.3 h of daily solar-assisted operation compared to a baseline vapour compression system. These findings highlight the potential of the TMVC system to significantly reduce energy usage and environmental impact, thereby supporting the deployment of sustainable cooling technologies in hot climate regions. Full article

Conveyor belts are critical in various industries, particularly in the barrier eddy current separator systems used in recycling processes. However, hidden issues, such as belt misalignment, excessive heat that can lead to fire hazards, and the presence of sharp or irregularly shaped materials, reduce operational efficiency and pose serious threats to the health and safety of personnel on the production floor. This study presents an intelligent monitoring and protection system for barrier eddy current separator conveyor belts designed to safeguard machinery and human workers simultaneously. In this system, a thermal camera continuously monitors the surface temperature of the conveyor belt, especially in the area above the magnetic drum—where unwanted ferromagnetic materials can lead to abnormal heating and potential fire risks. The system detects temperature anomalies in this critical zone. The early detection of these risks triggers audio–visual alerts and IoT-based warning messages that are sent to technicians, which is vital in preventing fire-related injuries and minimizing emergency response time. Simultaneously, a machine vision module autonomously detects and corrects belt misalignment, eliminating the need for manual intervention and reducing the risk of worker exposure to moving mechanical parts. Additionally, a line-scan camera integrated with the YOLOv11 AI model analyses the shape of materials on the conveyor belt, distinguishing between rounded and sharp-edged objects. This system enhances the accuracy of material separation and reduces the likelihood of injuries caused by the impact or ejection of sharp fragments during maintenance or handling. The YOLOv11n-seg model implemented in this system achieved a segmentation mask precision of 84.8 percent and a recall of 84.5 percent in industry evaluations. Based on this high segmentation accuracy and consistent detection of sharp particles, the system is expected to substantially reduce the frequency of sharp object collisions with the BECS conveyor belt, thereby minimizing mechanical wear and potential safety hazards. By integrating these intelligent capabilities into a compact, cost-effective solution suitable for real-world recycling environments, the proposed system contributes significantly to improving workplace safety and equipment longevity. This project demonstrates how digital transformation and artificial intelligence can play a pivotal role in advancing occupational health and safety in modern industrial production. Full article

Heat pumps are widely regarded as a key technology for sustainable heating, offering a pathway to significantly reduce fossil fuel dependency and combat the climate crisis. However, replacing individual gas boilers with heat pumps in multi-unit residential buildings remains a substantial challenge despite its immense potential to lower urban greenhouse gas emissions. To address this, the following paper describes the development of a compact, modular heat pump system designed to replace conventional gas boilers, focusing on the building and testing of a prototype for such a modular heat pump system. The prototype supports multiple functionalities, including space heating, cooling, and domestic hot water production. The performance advantages of two different compressor technologies were exploited to optimize the efficiency of the complete system and the pressure lifts associated with applications for heating and domestic hot water production. Thus, measurements were conducted across a range of operating points, comparing different heat pump module types. In the case of the piston compressor module, the Carnot efficiency was in the range of 47.2% to 50.4%. The total isentropic efficiency for floor heating and domestic hot water production was above 0.45 for both piston and rotary compressors. Full article

Water systems with pipes embedded in the horizontal concrete core slabs can be used for efficient space heating and cooling of passive and low-energy buildings. ISO 11855-4 describes the hourly simulation method of such systems while recommending to use other simulation tools to assess heat flow by transmission to the ambient environment. As it plays an important role in the thermal balance of a conditioned zone, this paper presents two calculation methods to obtain heat flow through the envelope. They were integrated with a general algorithm given in ISO 11855-4 and the simulation tool was developed. To validate the presented solution measurements were performed in a passive office building during the heating (November) and cooling (July) periods. The total heat transfer coefficient by transmission was measured and compared with the theoretical design value. Both proposed simulation algorithms provided results with very good accuracy. In the first period, the mean absolute of percentage error (MAPE) of the indoor air and floor temperatures amounted to 0.65% and 0.75%, respectively. Simulations showed that heating demand was covered mainly by the floor (28.7%), internal gains (21.7%), and ceiling (18.7%), while heat loss to the environment was mainly due to external partitions (94.0%). In the second period MAE and MAPE did not exceed 0.19 °C and 0.90%, respectively. Floor and ceiling were mainly responsible for heat gains removal (61%). Solar radiation was the main source (91%) of internal gains. The results obtained confirmed the assumptions taken. The simulation programme developed does not require the use of additional tools. Full article

Qinghai Province urgently requires the development of adaptive energy-efficient rural housing construction to address resettlement needs arising from hydropower projects, given the region’s characteristic combination of high solar irradiance resources and severe cold climate conditions. This research establishes localized retrofit strategies through systematic field investigations and Rhinoceros modeling simulations of five representative rural residences across four villages. The key findings reveal that comprehensive building envelope retrofits achieve an 80% reduction in energy consumption. South-facing sunspaces demonstrate effective thermal buffering capacity, though their spatial depth exhibits negligible correlation with heating energy requirements. An optimized hybrid shading system combining roof overhangs and vertical louvers demonstrates critical efficacy in summer overheating mitigation, with vertical louvers demonstrating superior thermal and luminous regulation precision. Architectural orientation analysis identifies an optimal alignment within ±10° of true south, emphasizing the functional zoning principle of positioning primary living spaces in south-oriented ground floor areas while locating auxiliary functions in northeastern/northwestern zones. The integrated design framework synergizes three core components: passive solar optimization, climate-responsive shading mechanisms, and performance-enhanced envelope systems, achieving simultaneous improvements in energy efficiency and thermal comfort within resettlement housing constraints. This methodology establishes a replicable paradigm for climate-resilient rural architecture in high-altitude, solar-intensive cold regions, effectively reconciling community reconstruction needs with low-carbon development imperatives through context-specific technical solutions. Full article

The smart capsule bubble tile (SCBT) is an innovative flooring solution that combines acupressure-based reflexology with electromagnetic wave stimulation to enhance well-being. Designed for smart buildings and healthcare applications, SCBT integrates traditional construction techniques with advanced healing technologies to create a health-conscious, eco-friendly flooring system. For durability and thermal performance, SCBT tiles are manufactured using conventional concrete methods, enhanced with aluminum oxide (Al₂O₃). Each tile contains multiple pressure point capsules featuring a copper cap that emits electromagnetic waves when exposed to sunlight. This dual-function mechanism stimulates acupressure points on the feet, promoting better blood circulation, reducing stress, and enhancing relaxation. The heat release from the copper caps further improves thermal comfort and energy flow in the body, reinforcing the benefits of reflexology. The performance of SCBT tiles was extensively tested, demonstrating impressive physical and functional properties. They exhibit a flexural strength of 4.6 N/mm², a thermal emissivity of 0.878, a solar reflectance of 0.842, and a water absorption rate of 8.12%. In biomechanical assessments, SCBT showed significant benefits for balance and posture correction. Users experienced a 70.8% reduction in lateral stance ellipse area with eyes open and a 50.5% reduction with eyes closed, indicating improved stability and proprioception. By integrating acupressure and electromagnetic stimulation into flooring design, SCBT promotes a holistic approach to health. This technology supports energy efficiency in smart buildings and contributes to preventive healthcare by enhancing musculoskeletal health and reducing fatigue. SCBT represents a significant step in creating built environments supporting human well-being, merging traditional healing principles with modern material science. Full article

This study adopts neighborhood blocks as the object of study, with the aim of investigating their thermal environment. In addition, the spatial configuration of various lands and the spatial configuration of building combinations are analyzed. The ideal model is then researched, and ENVI−met is used to create a simulation. A statistical analysis reveals a discernible correlation between the direction of the land, the layout of the building plane, floor height, average building height, the building density index, and the thermal environment. However, no such correlation was found between land area, land shape, floor height, and the thermal environment of neighborhood blocks. This study determined that to optimize the thermal environment of neighborhood blocks, it is imperative to construct a 250 m × 150 m road network system during the controlled detailed planning and block design stages. The road network should not run in the south-north direction, and the arrangement of neighborhood blocks should be integrated with urban wind corridors to mitigate the generation of a heat island effect caused by large concentrated residential areas. The combination that increases average building height and reduces building density should be selected, and the building enclosure and layout of ground-floor commercial buildings should be appropriately increased, positioned parallel to the dominant wind direction. Full article

The rapid urbanization of developing cities has intensified the challenge of maintaining thermal comfort in buildings, particularly in hot–humid climates. This study investigates the impact of floor level on airflow patterns and indoor temperatures in multi-purpose mid-rise buildings in Onitsha, Nigeria, where increasing urban density and frequent power outages necessitate effective passive cooling strategies. Through a mixed-method approach combining empirical measurements, computational fluid dynamics (CFD) simulations, and thermal performance analysis, the research examined variations in ventilation rates and temperature distributions across different floor levels of a six-story educational building over an annual cycle, focusing on the hottest (27 February), coldest (28 December), most windy (3 April), and least windy (17 September) days. Results revealed distinct floor-level ventilation patterns: upper floors (fourth–fifth) achieved 39–40 air changes per hour (ACH) during hot periods while maintaining temperatures of 30–35 degrees Celsius (°C); middle floors (second–third) showed moderate ventilation (15–22 ACH) but experienced heat accumulation (35–42 °C); and lower floors reached 20 ACH during windy conditions. Temperature stratification varied from 15 °C between floors across the entire building during peak conditions to 7 °C during windy periods. Stack-driven ventilation in upper floors contributed to temperature reductions of up to 3 °C, while wind-driven ventilation promoted uniform temperature distribution across all levels. These findings informed floor-specific design recommendations: hybrid ventilation systems with automated controls, strategic architectural features including a minimum floor level area of 15% for the central atrium, and comprehensive monitoring systems with six temperature sensors per floor. This study provides evidence-based strategies for optimizing thermal comfort in tropical urban environments, particularly valuable for designing energy-efficient buildings in rapidly developing cities with hot-humid climates. Full article

Due to severe global energy issues and the widespread demand for high-quality winter heating, this study designed a new type of graphene-based electrically heated solid wood composite floor. This flooring maintains the convenience of a traditional floor installation while providing users with a more comfortable living experience. Additionally, the low-temperature heating and temperature regulation system further reduces energy consumption, offering a new perspective for green home living. This paper introduces the overall structure and temperature control system of the graphene-heated solid wood composite flooring. Based on the above reasons, the working mechanism and heat transfer process of the graphene-heated flooring were analyzed, and a mathematical model was established. Furthermore, simulations of flooring with different thicknesses were conducted to determine temperature rise curves and corresponding times. Finally, a comparative experimental verification was conducted on the thermodynamic performance of the solid wood composite graphene flooring. The results showed that in the case of a floor with an 18 mm thickness, the time for the surface layer of the floor to reach 22 °C is 27 min; the time to reach 26 °C is 56 min; and that the time to reach 28 °C is 109 min. The time required to return to 22 °C after the power has been switched off is 25 min. The results also showed that one hour after the power was turned off, the surface temperature of the floor was still above 20 °C. The study shows that the graphene-heated flooring can be used to achieve high-quality heating. Full article

The development of 5G application technology has led to a rapid expansion in the scale of internet data center rooms and the number of servers. Due to the high heat generation of data center server equipment and the mixing of hot and cold airflows within the rooms, the thermal environment of these rooms fails to meet operational requirements with increasing energy consumption and thermal density. This study utilized the 6SigmaDC software to simulate and analyze the characteristics and existing problems of airflow distribution in a small-scale data center. Based on identified issues with current airflow patterns, two optimization schemes were proposed, analyzing the effects of raised floor height and the closure of aisles on airflow optimization. The return heat index (RHI) was used as an evaluation metric to assess airflow patterns before and after optimization. When the raised floor height was 600 mm, the maximum temperature at the cabinet inlet and outlet were 19.3 °C and 34 °C respectively, which were the lowest, and the RHI value was 0.9622. Compared with unclosed aisles and closed hot aisles, closed cold aisles effectively reduced the cabinet inlet and outlet temperature and increased the RHI. In addition, closed cold aisles increased the air supply temperature from 18 °C to 20 °C, further reducing the energy consumption of the air conditioning system. This study can provide guidance and act as a reference for optimizing airflow design and energy conservation in small data centers. Full article

The development of the fluorescent lamp and the air-conditioning system resulted in buildings being lit inexpensively without having to rely on daylighting to save energy, as was the case during the incandescent lamp era. Consequently, architects were able to design buildings with deep floor plates for maximum occupancy, placing workstations far away from windows since daylighting was no longer a necessity. Floor-to-ceiling heights became lower to minimize the inhabitable volumes that needed to be cooled or heated. With the rising costs of land in some major American cities such as New York City and Chicago at the beginning of the twentieth century, developers sought to optimize their investments by erecting tall structures, giving rise to densely inhabited city centers with massive street canyons that limit sunlight access in the streets. Today, there is growing awareness in terms of the impact of the built environment on people’s health especially in terms of the health benefits of natural light. The fact that buildings, through their shapes and envelope, filter a large amount of daylight, which may impact building occupants’ health and well-being, should cause architects and building developers to take this issue seriously. The amount and quality of light we receive daily impacts many of our bodily functions and consequently several aspects of our health and well-being. The human circadian rhythm is entrained by intrinsically photosensitive retinal ganglion cells (ipRGCs) in our eyes that are responsible for non-visual responses due to the presence of a short-wavelength sensitive pigment called melanopsin. The entrainment of the circadian rhythm depends on several factors such as the intensity, wavelength, timing, and duration of light exposure. Recently, this field of research has gained popularity, and several researchers have tried to create metrics to quantify photopic light, which is the standard way of measuring visual light, into a measure of circadian effective lighting. This paper discusses the relationship between different parameters of daylighting and their non-visual effects on the human body. It also summarizes the existing metrics of daylighting, especially those focusing on its effects on the human circadian rhythm and its shortcomings. Finally, it discusses areas of future research that can address these shortcomings and potentially pave the way for a universally acceptable standardized metric. Full article

A whole series of factors influence the temperature of the soil surface and surface layers. The soil surface is heated by solar radiation during the day. It radiates some of the obtained heat at night. The heat exchange between the soil and the atmosphere depends on the air and soil temperatures and the speed of air movement. Precipitation may also affect surface soil layers, but this was not considered in this study. In the mentioned interaction, a specific temperature field of the surface layers of the soil is established. To increase the building’s energy efficiency, the aim is to optimize the operation of its heating and cooling systems and to reduce heat loss to the environment as much as possible. Heat loss through the floor of the building or the walls of the recessed part into the ground changes the established temperature field of the ground. The heat spreads in the soil and is given to the atmospheric air. During the research, to validate the numerical model, the heat flow density was analysed to determine how it changes while maintaining a constant temperature of the heating surface at a certain depth of the soil. It was found that the new thermodynamic equilibrium, depending on the seasonality, can be reached in a time interval of up to a week. The temperature change in the artificially limited volume of the ground under the building or next to it can be treated as the work of the ground thermo-accumulator: its charge or discharge by heat. This makes it possible to reduce the annual energy costs of the building by more than ten percent. Full article