Search Results (125)

According to the United Nations Environment Programme reports, buildings are responsible for nearly 40% of energy-related emissions; therefore, energy-optimized building design is crucial to reduce the reliance on non-renewable energy sources as well as greenhouse gas emissions. The OECD reports indicate the use of Building Information Modelling (BIM) as one of the effective strategies for decarbonization of buildings, since a 3D digital representation of both physical and functional characteristics of a building can help to design a more efficient infrastructure. An efficient integration of solar energy in building design can be vital for the enhancement of energy performance in terms of heating, cooling, and lighting demand. This paper presents results of an analysis of how factors related to the use of daylight, such as automatic control of artificial lighting, external shading, or the visual absorptance of internal surfaces, influence the energy efficiency within an example room in two different climatic zones. The simulation was conducted using Design Builder software, with predefined occupancy schedules and internal heat gains, and standard EPW weather files for Warsaw and Genua climate zones. The study indicates that for the examined room, when no automatic sunshades or a lighting control system is utilized, most of the final energy demand is for cooling purposes (45–54%), followed by lighting (42–43%), with only 3–12% for heating purposes. The introduction of sunshades and/or the use of daylight allowed for a reduction of the total demand by up to half. Moreover, it was pointed out that often neglected factors, like the colour of the internal surfaces, can have a significant effect on the final energy consumption. In variants with light interior, the total energy consumption was lower by about 3–4% of the baseline demand, compared to their corresponding ones with dark surfaces. These results are consistent with previous studies on daylighting strategies and highlight the importance of considering both visual and thermal impacts when evaluating energy performance. Similarly, possible side effects of certain actions were highlighted, such as an increase in heat demand resulting from a reduced need for artificial lighting. The results of the analysis highlight the potential of a simulation-based design approach in optimizing daylight use, contributing to the broader goals of building decarbonization. Full article

The production of thermal energy in buildings using internal greenhouses makes it possible to obtain substantial gains in energy consumption and, at the same time, contribute to improving occupants’ thermal comfort (TC) levels. This article proposes a study on the producing and transporting of renewable thermal energy in a circular auditorium equipped with an enveloping semi-circular greenhouse. The numerical study is based on software that simulates the building geometry and the building thermal response (BTR) numerical model and assesses the TC level and indoor air quality (IAQ) provided to occupants in spaces ventilated by the proposed system. The building considered in this study is a circular auditorium constructed from three semi-circular auditoriums supplied with internal semi-circular greenhouses. Each of the semi-circular auditoriums faces south, northeast, and northwest, respectively. The semi-circular auditoriums are occupied by 80 people each: the one facing south throughout the day, while the one facing northeast is only occupied in the morning, and the one facing northwest is only occupied in the afternoon. The south-facing semi-circular greenhouse is used by itself to heat all three semi-circular auditoriums. The other two semi-circular greenhouses are only used to heat the interior space of the greenhouse. It was considered that the building is located in a Mediterranean-type climate and subject to the typical characteristics of clear winter days. The results allow us to verify that the proposed heating system, in which the heat provided to the occupied spaces is generated only in the semi-circular greenhouse facing south, can guarantee acceptable TC conditions for the occupants throughout the occupancy cycle. Full article

This paper presents the results of laboratory tests on the intensity of mass and heat exchange in a polytunnel, with a focus on the synergy between the polytunnel and a stone accumulator. The subject of study was a standard polytunnel made of double polythene sheathing. In the process of selecting the appropriate working conditions for such a polytunnel, the characteristic operating parameters were modeled and verified. They were related to the process of mass and energy exchange, which takes place in regular controlled-environment agriculture (CEA). Then, experimental tests of a heat accumulator on a fixed stone bed were carried out. The experiments were carried out for various accumulator surfaces ranging from 18.7 m² to 74.8 m², which was measured perpendicularly to the heat medium. To standardize the results obtained, the analysis included the unit area of the accumulator and the unit time of the experiment. In this way, 835 heat and mass exchange events were analyzed, including 437 accumulator charging processes and 398 discharging processes from April to October, which is a standard period of polytunnel use in the Polish climate. During the tests, internal and external parameters of the process were recorded, such as temperature, relative humidity, solar radiation, wind speed and air flow speed in the accumulator system. Based on the parameters, a set of empirical relationships was developed using mathematical modeling. This provided the foundation for calculating heat gains as a result of its storage in a stone accumulator and its discharging process. The research results, including the developed dependencies, not only fill the scientific gap in the field of heat storage, but can also be used in engineering design of polytunnels supported by a heat storage system on a stone bed. In addition, the proposed methodology can be used in the study of other heat accumulators, not only in plant production facilities. Full article

While natural grass has been a reliable recreational surface for decades, artificial turf has gained popularity due to its durability, supposed ability to save water, and lower associated costs for municipalities and schools. Growing environmental and health concerns associated with artificial turf have prompted a necessary comparison of the environmental impact, chemical exposure, injury rates, surface heat, and costs of turf with natural grass. The township of Verona, New Jersey, engaged the PSEG Institute for Sustainability Studies’ Green Teams Program interns to perform an environmental impact assessment, literature review, and cost–benefit analysis to determine if the township should restore an aging artificial turf field in the town to natural grass. The environmental impact assessment revealed concerns regarding artificial turf’s high emission profile, microplastic pollution, lack of permeability, and the presence of per- and polyfluoroalkyl substances (PFAS). Natural grass’ high water usage was also identified as a drawback. The literature review revealed safety concerns of artificial turf regarding temperature disparities and no conclusive results regarding differences in overall injury rates. The artificial turf field in this case study was 182% hotter than the natural grass field when measured by an infrared thermometer during mid-day readings in June. The cost–benefit analysis revealed that natural grass offers a lower long-term expense over a 25-year period. Artificial turf has many benefits; however, natural grass was the recommended option when considering environmental sustainability, reduced chemical exposure, lower surface temperatures, and overall cost. The conclusions may further inform policy decisions and support the adoption of environmentally responsible and health-centered practices for sports fields across municipalities in New Jersey and beyond. Full article

Projected changes in outdoor environmental conditions are expected to significantly alter building energy demand across the United States. Yet, policymakers and designers lack typology and climate-zone-specific guidance to support long-term planning. We simulated 10 U.S. Department of Energy (DOE) prototype buildings across all 16 ASHRAE climate zones with EnergyPlus. Future weather files generated in Meteonorm from a CMIP6 ensemble reflected two emissions pathways (RCP 4.5 and RCP 8.5) and two planning horizons (2050 and 2080), producing 800 simulations. Envelope parameters and schedules were held at DOE reference values to isolate the pure climate signal. Results show that cooling energy use intensity (EUI) in very hot-humid Zones 1A–2A climbs by 12% for full-service restaurants and 21% for medium offices by 2080 under RCP 8.5, while heating EUI in sub-arctic Zone 8 falls by 14–20%. Hospitals and large hotels change by < 6%, showing resilience linked to high internal gains. A simple linear-regression meta-model (R² > 0.90) links baseline EUI to future percentage change, enabling rapid screening of vulnerable stock without further simulation. These high-resolution maps supply actionable targets for state code updates, retrofit prioritization, and long-term decarbonization planning to support climate adaptation and sustainable development. Full article

In the automotive industry, the increasing stringent standards to reduce fuel consumption and pollutant emissions has driven significant advancements in turbocharging systems. The centrifugal compressor, as the most widely used power-absorbing machinery, plays a crucial role but remains one of the most complex components to study and design. While most numerical studies rely on adiabatic models, this work analyses several Computational Fluid Dynamics (CFD) models with conjugate heat transfer (CHT) of varying complexity, incorporating real solid components. This approach allowed a sensitivity analysis of the performance obtained from the different models compared to the adiabatic case, highlighting the effects of internal heat exchange losses. Moreover, an analysis of the temperature distribution of the wheel was conducted, along with a thermal assessment of the various heat flux contributions across the different components, to gain a deeper understanding of the performance differences. The impact of including the seal plate has been evaluated and different boundary conditions on the seal plate have been tested to assess the uncertainty in the results. Finally, the influence of heat exchange between the shroud and the external environment is also examined to further refine the model’s accuracy. One of the objectives of this work is to obtain a correct temperature profile of the rotor for a subsequent thermo-mechanical analysis. Full article

Peanut butter, a plant-based spread, has gained global prominence due to the increasing consumer demand for nutritious convenience foods and the rising adoption of plant-based diets. However, oil separation during storage and transportation accelerates the oxidative rancidity and reduces the shelf life of peanut butter. Enhancing peanut butter stability by minimizing oil separation is therefore essential. This study investigates the effect of soluble soybean polysaccharides (SSPSs) on the quality and shelf life of peanut butter. Optimal processing conditions were established by adding 1.7% SSPS (w/w), heating the mixture to 85 °C for 40 min, and then cooling it to 1 °C. The addition of SSPSs significantly increased the lightness of the peanut butter without altering its red-green color characteristics. Furthermore, SSPS incorporation improved its textural properties by increasing hardness and cohesiveness. Nutritional analysis showed that SSPS supplementation elevated proximate composition parameters (moisture, ash, carbohydrates, and fiber) while slightly reducing acid and peroxide values. Scanning electron microscopy revealed that SSPSs enhanced the internal network structure of peanut butter, inhibited oil migration, and reduced centrifugal emulsification rates. First-order kinetic models based on acid and peroxide values were developed to predict the effects of SSPSs on shelf life. Both the model predictions and experimental data confirmed that SSPS addition effectively extends the shelf life of peanut butter. Full article

This study investigates the long-term impact of insulation degradation on building heating energy consumption, with a focus on extruded polystyrene (XPS) insulation. Year-by-year degradation in thermal transmittance was derived from long-term experimental data and applied to prototypical energy models of multifamily apartment buildings and office buildings. Simulations were performed using both Actual Meteorological Year (AMY) and Typical Meteorological Year (TMY) data for six cities representing Korea’s major climate zones. The results showed that insulation degradation led to a significant increase in heating energy consumption from 23.2% to 34.9% in AMY simulations and 23.5% to 36.2% in TMY simulations for multifamily apartment buildings over 15 years. The difference between the AMY and TMY estimates was within 4%, demonstrating the reliability of TMY for long-term performance assessments. Notably, the southern and Jeju zones exhibited higher sensitivity to degradation due to their relaxed insulation standards and lower initial thermal performance. Office buildings were less affected, with increases below 8%, attributed to smaller envelope areas and higher internal heat gains. These findings highlight the need for zone-specific insulation standards and differentiated energy-saving design strategies by building type to ensure long-term energy efficiency. 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

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

Passive buildings are increasing in popularity in Canada. This paper examines two passive buildings initially constructed in the past decade: the Peterborough passive multi-unit residential building (MURB) and the Wolfe Island single-family dwelling. A post-occupancy evaluation was performed on the buildings. The buildings were modelled in HOT2000 and the Passive House Planning Package (PHPP) to ensure the validity of the results. The energy bills were collected from the building owners to acquire the real-time consumption of the buildings. The models have shown a good agreement with the collected data. Furthermore, data loggers were installed in both buildings for indoor temperature monitoring to ensure that they adhere to the passive house explicit criteria. Internal gains, shading, and orientation were analyzed to assess their effect on heating and cooling loads. Peterborough MURB has shown more energy-saving potential compared to the Wolfe Island passive house. Heating load reduction has been compared, more than five times, to the cooling load reduction potential. The reduction in GHG emissions can be up to 39% when passive house parameters are applied to the Wolfe Island house. This paper has shown the potential of the passive house in relation to sustainable buildings in Northern climates. Full article

To achieve carbon neutrality by 2050, the realization of Net-Zero-Energy Buildings (ZEBs) and the proper design of heat source equipment capacity are essential. Consequently, numerous studies have been conducted to prevent overdesign. However, most previous studies have analyzed the factors influencing heat source equipment capacity as independent and isolated variables. In actual design practice, however, factors interact in complex and interdependent ways, yet few studies have considered the interrelationships among these factors or conducted a structural and comprehensive analysis of their influence on heat source equipment capacity. Therefore, this study aims to quantitatively model the influence structure between design factors and heat source equipment capacity using Structural Equation Modeling (SEM), focusing on office buildings with a central heat source system in warm regions of Japan. This research offers a novel perspective not found in previous studies by structurally and comprehensively analyzing the relationship between design factors and heat source equipment capacity, examining the interactions between the factors and their impact on equipment capacity in stages. As a result, by modeling the influence structure, it was confirmed that the diversity factor, handling of internal heat gain, and appropriate design based on actual building usage, such as internal heat gain and the safety factor, are effective for optimizing heat source equipment capacity. Moreover, the result also confirmed that industry, company size, building scale, building use, and software influence the above design factors. This study is a case study that focuses on the maximum heat load calculation in mechanical equipment design and attempts to model the influence of design factors and heat source equipment capacity. However, it is expected that future studies using the same methodology as this study and incorporating additional factors not discussed in this study, and expanding across various regions, will provide a valuable and effective approach to optimizing heat source equipment capacity. Full article

The present study was focused on assessing the molten salt-induced hot corrosion resistance of selective laser melting (SLM) manufactured Inconel 625 at 900 °C for 96 h and investigating the possibility of improving the superalloy’s corrosion resistance by applying a pre-oxidation heat treatment. The material’s hot corrosion properties were assessed in a heat-treated state (heat treatments performed at 1000 °C/1 h and 1150 °C/1 h, respectively) with and without pre-oxidation. The heat treatment at 1000 °C promoted the columnar dendrite morphology evolution, while the heat treatment at 1150 °C promoted the equiaxed dendrite morphology evolution. At 1150 °C, microstructural features specific to conventional manufactured material developed (annealing twin boundaries). They are considered a sign of anisotropy reduction due to equiaxed grains forming and it is believed that the internal stress in the material is reduced. High-temperature pre-oxidation heat treatment at 900 °C for 96 h ensured the formation of protective oxide scales with a reduced thickness (1.74 μm in the case of samples’ heat-treated at 1000 °C, and 2.22 μm in the case of samples’ heat-treated at 1150 °C, respectively). Experimentally, based on weight gain and oxide scale analysis, it was proven that pre-oxidation can improve the hot corrosion resistance of SLM manufactured Inconel 625 by forming a stable and protective oxide scale on the surface of the alloy before exposure to molten salts. The preformed oxide layer acts as a barrier for the corrosive species, reducing the formation of detrimental compounds, especially Mo-rich sulfides. Based on the tests, an improvement in corrosion resistance of up to 33.94% was observed in samples heat-treated at 1150 °C with pre-oxidation compared to samples heat-treated at 1000 °C without pre-oxidation. Full article

The use of parts containing internal channels fabricated by laser powder bed fusion (LPBF) in maraging steel is gaining attention within industry, due to the promising application of the material in molds and forming tools. However, LPBF processing has issues when it comes to unsupported channels, leading to defects that can result in a limited performance and shortened component life. The present study aims to provide a detailed evaluation of the metallurgical effects arising from the LPBF printing of channels made of maraging 300 steel. The results show that channel distortion occurs due to the lack of support, associated with increased roughness at the top part of the channel profile caused by partial melting and loosening of the powder. Statistical analyses showed that distortion is significantly affected by channel length. A high level of porosity derived from a lack of fusion was observed in the region above the channel and was attributed to layer irregularities caused by the absence of support, with a predominance of large and irregular pores. Residual stresses, always of a tensile nature, present a behavior opposed to that of distortion, increasing with increases in length, meaning that higher levels of distortion lead to an enhanced effect of stress accommodation/relief, with porosity having a similar effect. All these phenomena, however, did not seem to affect crystallographic orientation, with a nearly random texture in all cases, most likely due to the energy input used and to an optimized laser scanning strategy. These findings are vital to increase the amount of attention paid towards the design of internal channels, especially with those with the purpose of coolant circulation, since distortions and poor surface finishing can reduce cooling efficiency due to a defective fluid flow, while porosity can have the same effect by hindering heat transfer. Residual stress, in its turn, can decrease the life of the component by facilitating cracking and wear. Full article

Direct wide-bandgap III-Ns and II-Os have recently gained considerable attention due to their unique electrical and chemical properties. These novel semiconductors are being explored to design short-wavelength light-emitting diodes, sensors/biosensors, photodetectors for integration into flexible transparent nanoelectronics/photonics to achieve high-power radio-frequency modules, and heat-resistant optical switches for communication networks. Knowledge of the elastic constants structural and mechanical properties has played crucial roles both in the basic understanding and assessing materials’ use in thermal management applications. In the absence of experimental structural, elastic constants, and mechanical traits, many theoretical simulations have yielded inconsistent results. This work aims to investigate the basic characteristics of tetrahedrally coordinated, partially ionic BeO, MgO, ZnO, and CdO, and partially covalent BN, AlN, GaN, and InN materials. By incorporating a bond-orbital and a valance force field model, we have reported comparative results of our systematic calculations for the bond length $\mathrm{d}$, bond polarity ${\mathsf{\alpha }}_{\mathrm{P}}$, covalency ${\mathsf{\alpha }}_{\mathrm{C}}$, bulk modulus $\mathrm{B}$, elastic stiffness $\mathrm{C}(={\displaystyle \frac{\left[{\mathrm{c}}_{11}-{\mathrm{c}}_{12}\right]}{2}})$, bond-stretching $\mathsf{\alpha }$ and bond-bending $\mathsf{\beta }$ force constants, Kleinmann’s internal displacement ζ, and Born’s transverse effective charge ${\mathrm{e}}_{\mathrm{T}}^{*}$. Correlations between $\mathrm{C}/\mathrm{B}$, $\mathsf{\beta }$/$\mathsf{\alpha }$, ${\displaystyle \frac{{\mathrm{c}}_{12}}{{\mathrm{c}}_{11}}},$ ζ, $\mathrm{a}\mathrm{n}\mathrm{d}$ ${\mathsf{\alpha }}_{\mathrm{C}}$revealed valuable trends of structural, elastic, and bonding characteristics. The study noticed AlN and GaN (MgO and ZnO) showing nearly comparable features, while BN (BeO) is much harder compared to InN (CdO) material, with drastically softer bonding. Calculations of microhardness $\mathrm{H}$, shear modulus $\mathrm{G},$ and Young’s modulus $\mathrm{Y}$ have predicted BN (BeO) satisfying a criterion of super hardness. III-Ns (II-Os) could be vital in electronics, aerospace, defense, nuclear reactors, and automotive industries, providing integrity and performance at high temperature in high-power applications, ranging from heat sinks to electronic substrates to insulators in high-power devices. Full article