SwePub
Sök i SwePub databas

  Extended search

Träfflista för sökning "L773:1873 684X "

Search: L773:1873 684X

  • Result 1-50 of 230
Sort/group result
   
EnumerationReferenceCoverFind
1.
  • Aarts, Mariëlle P.J., et al. (author)
  • Performance of personally worn dosimeters to study non-image forming effects of light : Assessment methods
  • 2017
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 117, s. 60-72
  • Journal article (peer-reviewed)abstract
    • When determining the effects of light on human beings, it is essential to correctly measure the effects, and to correctly measure the adequate properties of light. Therefore, it is important to know what is being measured and know the quality of the measurement devices. This paper describes simple methods for identifying three quality indices; the directional response index, the linearity index and the temperature index. These indices are also checked for several commonly used portable light measurement devices. The results stresses what was already assumed, the quality and the outcome of these devices under different circumstances were very different. Also, the location were these devices are normally worn has an impact on the results. The deviation range between worn vertically at eye level and the wrist is between 11% (outdoor) to 27% (indoor). The smallest deviation, both in indoor and outdoor, was found when the device was placed on the sides of the eye (7%). 
  •  
2.
  • af Klintberg, Tord, 1951-, et al. (author)
  • Air Gap Method : Dependence of water removal on RH in room and height of floor air gap
  • 2012
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 56, s. 1-7
  • Journal article (peer-reviewed)abstract
    • This study is performed in combined floor and wall constructions with air gaps within and with a heating cable in the vertical air gap. All surfaces of the air gap are covered with polystyrene plastic to avoid leakage into the construction. Wet gypsum boards that are weighed at start and end of experiment are used to measure the dry out process.Three different heights of the floor air gap, 25 mm, 15 mm and 5 mm are investigated. The influences of the RH in the surrounding room and of the wetness of the gypsum boards are also investigated.It is shown that the height of the floor air gap has a great impact on the rate of drying. The optimal height is less than 25 mm and somewhere between 15 and 5 mm.
  •  
3.
  • Albuquerque, Daniel P., et al. (author)
  • Experimental and numerical investigation of pumping ventilation on the leeward side of a cubic building
  • 2020
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 179
  • Journal article (peer-reviewed)abstract
    • Unstable interaction between shear layers that form in the wake of an isolated building exposed to wind can drive natural pumping ventilation in windward and leeward facing rooms with two or more horizontally separated openings. This paper presents an experimental and numerical study of pumping ventilation in a three-story cubic building with two leeward openings in its middle floor. Reduced-scaled measurements were performed in the University of Gävle atmospheric-boundary-layer wind tunnel. The ventilation mechanism was investigated using smoke visualization, hot wire anemometry and particle image velocimetry. Effective ventilation rates were obtained using a tracer gas decay method. Experimental results confirmed that pumping ventilation is a 3D oscillatory unstable phenomenon with periodic behavior over several oscillation cycles. Measured flowrates show a linear relation between the effective ventilation rate and window separation. The numerical simulations used two turbulence modeling approaches: unsteady Reynolds-averaged Navier-Stokes (URANS) and large eddy simulation (LES). Both URANS and LES could predict vortex shedding frequency with an error below 5%. LES showed a good agreement with the measured ventilation rates, with an error below 10%, while URANS underestimated ventilation rates by at least 40%. The ventilation efficiency, obtained by LES, ranged between 0.60 and 0.75 (for the case with larger window separation). The results show that LES may be a suitable simulation approach for pumping ventilation. In contrast, URANS cannot simulate pumping ventilation.
  •  
4.
  • Ameen, Arman, 1976-, et al. (author)
  • Numerical investigation of the flow behavior of an isothermal corner impinging jet for building ventilation
  • 2022
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 223
  • Journal article (peer-reviewed)abstract
    • The corner impinging jet concept has been proposed as a new air distribution system for use in office environments. The present paper reports the mean flow field behavior of an isothermal corner-based turbulent impinging jet in a room. A detailed experimental study is carried out to validate the numerical simulations, and the predictions are performed using three turbulence models. RNG k−ε model was chosen for this study. This study investigates the influence different configuration parameters such as jet discharge height, diffuser geometry (shape and size) and supply airflow rate have on the flow field. The results show that the diffuser geometries used in this study had in general a minor effect on the velocity developments along the centerline of the floor, maximum velocity decay and jet spreading rate except for some specific cases. When evaluating the triangle geometry cases, the results show that all the cases with volume flow <20 L/s are able to meet Boverket's building regulations velocity requirement both for summer and winter. The applicability evaluation show that the results can be considered for room sizes between ≈25 and 100 m2. In addition, the wall confinement effect (90° vs. 180°) is having a significant impact on the maximum velocity decay for corner impinging jet ventilation. In the regression analysis the results shows that the distance along the diagonal centerline of the room has the most impact on the evaluation of maximum velocity decay and jet spreading rate.
  •  
5.
  • Andersson, Harald, et al. (author)
  • Experimental and numerical investigations of a new ventilation supply device based on confluent jets
  • 2018
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 137, s. 18-33
  • Journal article (peer-reviewed)abstract
    • In developed countries, heating, ventilation, air conditioning (HVAC) systems account for more than 10% of national energy use. The primary function of a HVAC system is to create proper indoor environment. A number of ventilation strategies have been developed to minimize HVAC systems’ energy use whilst still maintaining a good indoor environment. Among these strategies are confluent jet ventilation and variable air volume. In this study, an air supply device with a novel nozzle design that uses both of the above-mentioned strategies was investigated both experimentally and numerically at three different airflow rates. The results from the numerical investigation using the SST k - ω turbulence model regarding velocities and flow patterns are validated by experimental data carried out by Laser Doppler Anemometry. The results from both studies show that the flow pattern and velocity in each nozzle is directly dependent on the total airflow rate. However, the flow pattern does not vary between the three different airflow rates. The numerical investigation shows that velocity profiles for each nozzle have the same pattern regardless of the airflow rate, but the magnitude of the velocity profile increases as the airflow increases. Thus, a supply device of this kind could be used for variable air volume and produce confluent jets for the airflow rates investigated.
  •  
6.
  • Antoniou, Nestoras, et al. (author)
  • CFD and wind-tunnel analysis of outdoor ventilation in a real compact heterogeneous urban area : evaluation using “air delay”
  • 2017
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 126, s. 355-372
  • Journal article (peer-reviewed)abstract
    • Outdoor urban ventilation in a real complex urban area is investigated by introducing a new ventilation indicator – the "air delay". Computational Fluid Dynamics (CFD) simulations are performed using the 3D steady Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches. The up-to-date literature shows the lack of detailed evaluations of the two approaches for real compact urban areas. This study further presents a systematic evaluation of steady RANS and LES for the assessment of the ventilation conditions in a dense district in Nicosia, Cyprus. The ventilation conditions within the urban area are investigated by calculating the distribution of the age of air. To better assess the outdoor ventilation, a new indicator, the "air delay" is introduced as the difference between the local mean age of air at an urban area and that in an empty domain with the same computational settings, allowing the comparison of the results in different parts of the domain, without impact of the boundary conditions. CFD results are validated using wind-tunnel measurements of mean wind speed and turbulence intensity performed for the same urban area. The results show that LES can accurately predict the mean wind speed and turbulence intensity with the average deviations of about 6% and 14%, respectively, from the wind-tunnel measurements while for the steady RANS, these are 8% and 31%, respectively. The steady RANS simulations overestimate the local mean air delay. The deviation between the two approaches is 52% at pedestrian level (2 m).
  •  
7.
  • Arghand, Taha, et al. (author)
  • An experimental investigation of the flow and comfort parameters for under-floor, confluent jets and mixing ventilation systems in an open-plan office
  • 2015
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 92, s. 48-60
  • Journal article (peer-reviewed)abstract
    • There is a new trend to convert the workplaces from individual office rooms to open offices for motivating money saving and better communication. With such a shift the ability of existing ventilation systems in meeting the new requirements is a challenging question for researchers. The available options could have an impact on workers' health in terms of providing acceptable levels of thermalcomfort and indoor air quality. Thus, this experimental investigation focuses on the performances of three different air distribution systems in an open-plan office space. The investigated systems were: mixing ventilation with ceiling-mounted inlets, confluent jets ventilation and underfloor air distribution with straight and curved vanes. Although this represents a small part of our more extensiveexperimental investigation, the results show that all the purposed stratified ventilation systems (CJV and UFAD) were more or less behaving as mixing systems with some tendency for displacement effects. Nevertheless, it is known that the mixing systems have a stable flow pattern but has the disadvantage of mixing contaminated air with the fresh supplied air which may produce lower performance and in worst cases occupants' illness. For the open-plan office we studied here, it will be shown that the new systems are capable of performing better than the conventional mixing systems. As expected, the higher air exchange efficiency in combination with lower local mean age of air for corner-mounted CJV and floor-mounted UFAD grills systems indicates that these systems are suitable for open-plan offices and are to be favored over conventional mixing systems.
  •  
8.
  • Arsenault, Helene, et al. (author)
  • Effects of glazing colour type on perception of daylight quality, arousal, and switch-on patterns of electric light in office rooms
  • 2012
  • In: Building and Environment. - : Elsevier BV. - 1873-684X .- 0360-1323. ; 56, s. 223-231
  • Journal article (peer-reviewed)abstract
    • A study is presented about the effects of three glazing colour types (blue, neutral, bronze) on daylight quality, arousal and switch-on patterns for electric lights. This study was carried out using a scale model (1:4) of an office room, where subjective evaluations of the luminous conditions were performed by 36 participants (mean age 23.8 years) with their upper bodies immersed in the model. The evaluations were achieved using questionnaires designed to assess five light quality factors: 1) visual comfort; 2) naturality; 3) pleasantness; 4) precision (of details and textures) and 5) light level. Mixed model analyses of the questions revealed significant higher scores for pleasantness (p = 0.003) comfort (p = 0.015) and light level (p = 0.044) for the bronze glazing type compared to the blue and neutral glazing, confirming results of earlier studies. Results from a paired t-test on the Karolinska Sleepiness Scale (KSS) scores indicated that the level of self-reported arousal decreased in presence of the blue glazing. However, the analysis did not reveal significant results regarding switch-on patterns of electric lights. Overall, the study shows that there is a preference for daylight filtered through bronze window glazing and that the glazing colour type may have a significant effect on arousal level of office workers. (C) 2012 Elsevier Ltd. All rights reserved.
  •  
9.
  • Assefa, Getachew, et al. (author)
  • Environmental assessment of building properties — Where natural and social sciences meet : the case of EcoEffect
  • 2007
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 42:3, s. 1458-1464
  • Journal article (peer-reviewed)abstract
    • The EcoEffect method of assessing external and internal impacts of building properties is briefly described. The external impacts of manufacturing and transport of the building materials, the generation of power and heat consumed during the operation phase are assessed using life-cycle methodology. Emissions and waste; natural resource depletion and toxic substances in building materials are accounted for. Here methodologies from natural sciences are employed. The internal impacts involve the assessment of the risk for discomfort and ill-being due to features and properties of both the indoor environment and outdoor environment within the boundary of the building properties. This risk is calculated based on data and information from questionnaires; measurements and inspection where methodologies mainly from social sciences are used. Life-cycle costs covering investment and utilities costs as well as maintenance costs summed up over the lifetime of the building are also calculated.The result presentation offers extensive layers of diagrams and data tables ranging from an aggregated diagram of environmental efficiency to quantitative indicators of different aspects and factors. Environmental efficiency provides a relative measure of the internal quality of a building property in relation to its external impact vis-à-vis its performance relative to other building properties.
  •  
10.
  • Assefa, Getachew, et al. (author)
  • Quality versus impact : Comparing the environmental efficiency of building properties using the EcoEffect tool
  • 2010
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 45:5, s. 1095-1103
  • Journal article (peer-reviewed)abstract
    • There are tools that are developed for the assessment of the environmental impact of buildings (e.g. ATHENA). Other tools dealing with the indoor and outdoor environmental quality of building properties (referred to as real estates in other literature) are also available (e.g. GBTool). A platform where both the aspects of quality and impact are presented in an integrated fashion are few. The aim of this contribution is to present how the performance of different building properties can be assessed and compared using the concept of environmental efficiency in a Swedish assessment tool called EcoEffect. It presents the quality dimension in the form of users' satisfaction covering indoor and outdoor performance features against the weighted environmental impact covering global and local impacts. The indoor and outdoor values are collected using questionnaires combined with inspection and some measurements. Life cycle methodology is behind the calculation of the weighted external environmental impact. A case study is presented to show the application of EcoEffect using a comparative assessment of Lindas and a Reference property. The results show that Lindas block is better in internal environment quality than the Reference property. It performs slightly worse than the Reference property in the external environmental impact due to emissions and waste from energy and material use. The approach of integrated presentation of quality and impact as in EcoEffect provides with the opportunity of uncovering issues problem shifting and sub-optimisation. This avoids undesirable situations where the indoor quality is improved through measures that result in higher external environmental impact.
  •  
11.
  • Azizi, Shoaib, et al. (author)
  • Application of Internet of Things in academic buildings for space use efficiency using occupancy and booking data
  • 2020
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 186
  • Journal article (peer-reviewed)abstract
    • Environmental sustainability in academic buildings can be improved with management interventions such as improving space use efficiency supported by large data from the Internet of Things (IoT). Due to the potentials, the interest in the use of IoT tools for facility management is high among universities. However, empirical studies on this topic are scarce. To address the knowledge gap in this area, this study proposes and examines a process model with steps to measure space use and to improve space use efficiency by IoT tools in academic buildings. The applicability of the model is investigated in 8 lecture halls in a university building by using occupancy and booking data from IoT tools. Four space use indicators are developed to visualize the data and quantify space use, and based on them, the strategies and interventions for space use efficiency are proposed and discussed.
  •  
12.
  • Barjot, Zoé, et al. (author)
  • Limit values in LCA-based regulations for buildings – System boundaries and implications on practice
  • 2024
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 259
  • Journal article (peer-reviewed)abstract
    • Rapidly reducing the climate impacts of the construction and use of buildings is acknowledged as a key lever to meet European and national climate goals. Life cycle-based regulations, in the form of mandatory declaration of the climate impact of new-build, are being introduced, often planned to be or already complemented with performance-based limit values. This development has increasingly raised questions on how different system boundaries for similar limit values applied in various countries might lead to diverging implications in practice. A sample of 50 real-life case buildings of different typologies, representative of contemporary Swedish construction, is used to compare implications of two different system boundaries for embodied GHGe assessment: SB1) life cycle modules A1-A5 i.e. initial, that is upfront GHGe and SB2) life cycle modules A1-A5 + B2–B4, i.e. adding recurring GHGe, according to the European EN 15978 standard. The results show that for the two system boundaries applied, no difference is seen concerning the sample buildings' ability to perform below a limit value as defined in current Swedish regulatory plans, nor would it lead to different design choices to ensure that a building performs below the limit value. The results of sensitivity analyses along with the relative nature of the results, suggest these conclusions are also relevant for other regulatory contexts. As a conclusion, this study shows that implementing LCA-based regulations focusing on initial embodied GHGe is an important step to rapidly and effectively address GHGe associated with new-build.
  •  
13.
  • Belarbi, Rafik, et al. (author)
  • Experimental and theoretical investigation of non-isothermal transfer in hygroscopic building materials
  • 2008
  • In: Building and Environment. - : Elsevier BV. - 1873-684X .- 0360-1323. ; 43:12, s. 2154-2162
  • Journal article (peer-reviewed)abstract
    • In this paper a modified two-dimensional Luikov model for evaluating the non-isothermal moisture migration in porous building materials was proposed. The coupled heat and moisture transfer problem was modeled. Vapor content and temperature were chosen as the principal driving potentials. The coupled equations were solved by a numerical method, which consists of a finite difference technique with a fully implicit scheme in time. Two validation experiments were developed in this study. The evolution of transient moisture distributions in both one-dimensional and two-dimensional cases wits measured. A comparison between experimental results and those obtained by the numerical model proves that they are fully consistent with each other. The modified model can be integrated into a whole building heat, air and moisture transfer model. (C) 2007 Elsevier Ltd. All rights reserved.
  •  
14.
  • Bluyssen, Philomena M., et al. (author)
  • Comfort of workers in office buildings : The European HOPE project
  • 2011
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 46:1, s. 280-288
  • Journal article (peer-reviewed)abstract
    • Previous studies have shown that building, social and personal factors can influence one's perceived health and comfort. The aim of the underlying study was to get a better understanding of the relationships between these factors and perceived comfort. Self-administered questionnaires from 5732 respondents in 59 office buildings and building-specific data from the European Health Optimisation Protocol for Energy-efficient buildings (HOPE) study were used. Principal Component Analysis (PCA), reliability analyses, and linear regression analysis were performed. The outcome showed that perceived comfort is strongly influenced by several personal, social and building factors and that their relationships are complex. Results showed that perceived comfort is much more than the average of perceived indoor air quality, noise, lighting and thermal comfort responses. Perceived comfort is a phenomenon that deserves more research.
  •  
15.
  •  
16.
  • Brown, Nils W. O., et al. (author)
  • Embodied greenhouse gas emissions from refurbishment of residential building stock to achieve a 50% operational energy reduction
  • 2014
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 79, s. 46-56
  • Journal article (peer-reviewed)abstract
    • Mitigating climate change through operational energy reduction in existing buildings is of highest priority for policy-makers in Europe and elsewhere. At the same time there is increasing understanding of the significance of impacts arising from material production for buildings. The aim of this work has therefore been to evaluate the importance of embodied GWP for refurbishment for operational energy reduction on a stockwide basis. It is further intended to judge the relative significance of embodied GWP for specific refurbishment measures implemented for operational energy reduction. We study the case of operational energy reduction in the Swedish residential building stock by 50% compared to 1995. The total embodied GWP to achieve the noted operational energy reduction is 0.35 Mt CO2-e/year. 83% of this total is due to ventilation and window measures alone. Compared with previous studies assessing GWP mitigation from operational energy reduction, the "GWP payback time" is just over 3 years. Many types of measure that contribute significantly to achieving the above operational energy goal had average embodied GWP between 10 and 20 g CO2-e/kW h operational energy reduction, notably window and ventilation measures. Indoor temperature reduction (to 20 degrees C), was also significant for stockwide operational energy reduction but had a very low GWP of 0.4 g CO2-e/kW h operational energy reduction. If this measure proves unfeasible to implement on a stockwide basis then more expensive measures with higher embodied GWP will be needed to achieve the stated energy reduction goal.
  •  
17.
  • Brown, Nils W. O., et al. (author)
  • Sustainability assessment of renovation packages for increased energy efficiency for multi-family buildings in Sweden
  • 2012
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 61, s. 140-148
  • Journal article (peer-reviewed)abstract
    • In this paper, we propose a method for assessing renovation packages drawn up with the goal of increasing energy efficiency. The method includes calculation of bought energy demand, life-cycle cost (LCC) analysis and assessment of the building according to the Swedish environmental rating tool Miljöbyggnad (MB). In this way the methodology assesses economic, indoor environmental quality (IEQ) and specifically environmental aspects associated with energy demand of such packages from a sustainability point-of-view. Through MB, energy efficiency packages are placed in context with other necessary measures required to improve environmental performance in buildings, providing a consistent and systematic basis other than simply financial performance by which to compare capital improvements. The method is further explained and analyzed by applying it in three case studies. In each case study a multi-family building representing a typologically significant class in the Swedish building stock is considered, and for each building a base case and two renovation packages with higher initial investment requirement and higher energy efficiency are defined. It is shown that higher efficiency packages can impact IEQ indicators both positively and negatively and that packages reducing energy demand by approx. 50% have somewhat higher LCC. Identified positive IEQ impacts point to added value for packages that may not otherwise be communicated, while negative impacts identify areas where packages need to be improved, or where MB indicators may be referred to as specifications in procurement procedures.
  •  
18.
  • Byström, Alexandra, et al. (author)
  • Full-scale experimental and numerical studies on compartment fire under low ambient temperature
  • 2012
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 51, s. 255-262
  • Journal article (peer-reviewed)abstract
    • A fire experiment with wood crib was conducted in a concrete building under low ambient temperature of −10 °C to explore fire development and temperature distribution. The concrete building consists of a two-storey compartment with the size of 9.0 m by 5.0 m by 4.8 m high and a four-storey stairwell with the size of 5.0 m by 2.4 m by 10.0 m high. The fuel mass loss rate and temperatures at different positions were measured. Two fire cases, with different assumed ambient temperatures of −10 °C and 20 °C respectively, were then simulated by using FDS software to investigate the effect of ambient temperature and compare with the experimental results. The numerical results show that the calculated heat release rate is in reasonably good agreement with the measured full-scale result before water suppression. The calculated temperatures in the hot combustion gas layer at different positions agree also very well with the measured values. However, the measured fresh air temperature at the floor level near the fire source is higher than the calculated value. This discrepancy may partly depend on measuring errors as analyzed in the paper.
  •  
19.
  • Cabovska, Blanka, 1990, et al. (author)
  • Ventilation strategies and indoor air quality in Swedish primary school classrooms
  • 2022
  • In: Building and Environment. - Göteborg : IVL Svenska Miljöinstitutet AB. - 0360-1323 .- 1873-684X. ; 226, s. 109744-109744
  • Journal article (peer-reviewed)abstract
    • The present study aimed at investigating the effects of ventilation strategies on indoor air quality (IAQ) in schools. Measurements of thermal environment and IAQ were performed over 5 school days in 45 primary school classrooms in Gothenburg, Sweden, grouped into three categories according to their ventilation system: category A) natural or exhaust ventilation, or automated window opening; category B) balanced mechanical ventilationsystems with constant air volume (CAV) and category C) balanced mechanical ventilation systems with variable air volume (VAV). The classrooms performed equally well with respect to temperature and relative humidity regardless of the ventilation system. The concentrations of the air pollutants in all classrooms were generally below the respective guideline values. The concentrations of CO2, formaldehyde, PM10, and PM2.5 were lower in the B and C category classrooms with higher ventilation rates than in the A category classrooms. Indoor Air Pollution Index integrating concentrations of multiple pollutants was significantly higher the A category classrooms, reflecting poorer IAQ. Majority of the classrooms had lower ventilation rates than the Swedish ventilation requirements. The periodically reduced ventilation rates in the classrooms with VAV systems did not lead to substantial increase in the measured indoor pollutant concentrations.
  •  
20.
  • Calzolari, Giovanni, et al. (author)
  • Deep learning to replace, improve, or aid CFD analysis in built environment applications : A review
  • 2021
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 206
  • Research review (peer-reviewed)abstract
    • Fast and accurate airflow simulations in the built environment are critical to provide acceptable thermal comfort and air quality to the occupants. Computational Fluid Dynamics (CFD) offers detailed analysis on airflow motion, heat transfer, and contaminant transport in indoor environment, as well as wind flow and pollution dispersion around buildings in urban environments. However, CFD still faces many challenges mainly in terms of computational expensiveness and accuracy. With the increasing availability of large amount of data, data driven models are starting to be investigated to either replace, improve, or aid CFD simulations. More specifically, the abilities of deep learning and Artificial Neural Networks (ANN) as universal non-linear approximator, handling of high dimensionality fields, and computational inexpensiveness are very appealing. In built environment research, deep learning applications to airflow simulations shows the ANN as surrogate, replacement for expensive CFD analysis. Surrogate modeling enables fast or even real-time predictions, but usually at a cost of a degraded accuracy. The objective of this work is to critically review deep learning interactions with fluid mechanics simulations in general, to propose and inform about different techniques other than surrogate modeling for built environment applications. The literature review shows that ANNs can enhance the turbulence model in various way for coupled CFD simulations of higher accuracy, improve the efficiency of Proper Orthogonal Decomposition (POD) methods, leverage crucial physical properties and information with physics informed deep learning modeling, and even unlock new advanced methods for flow analysis such as super-resolution techniques. These promising methods are largely yet to be explored in the built environment scene. Unavoidably, deep learning models also presents challenges such as the availability of consistent large flow databases, the extrapolation task problem, and over-fitting, etc.
  •  
21.
  •  
22.
  • Carrilho da Graça, Guilherme, et al. (author)
  • Pumping ventilation of corner and single sided rooms with two openings
  • 2021
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 205
  • Journal article (peer-reviewed)abstract
    • Corner rooms with two or more open windows in perpendicular facades can be naturally ventilated in cross-ventilation or pumping ventilation. These two airflow regimes also occur in rooms with two openings in the same façade, in the form of single sided pumping or cross sided ventilation. This paper presents an experimental and numerical simulation study of the scale and occurrence of these two flow regimes for rooms in a rectangular building exposed to wind. Flow visualization and tracer gas measurement of effective airflow were performed in an atmospheric boundary layer wind tunnel using a rectangular model of a three-story building (1/20 scale) with a ventilated middle floor. Experimental results show that pumping ventilation occurs when the wind is perpendicular to the façade (single sided rooms) or aligned with the building corner (corner rooms). In addition to these two perfectly aligned wind directions, pumping also occurs for a range of incoming wind angles: ±19° for single sided; and ±9° for corner rooms. As a result, for isolated rectangular buildings that have, at least, one single sided and two corner rooms in each facade, pumping ventilation can potentially occur in two or more rooms for 62 % of incoming wind directions. To investigate the transition between steady cross-ventilation and unsteady pumping ventilation, three-dimensional computational fluid dynamics large eddy simulations were performed to obtain wind generated pressures in the ventilation openings. Results show that the transition from cross-ventilation to pumping occurs when the steady pressure becomes smaller than the unsteady component. These results are used to develop a pressure based simplified model for corner ventilation that can predict effective airflow from external wind generated pressures with an average error below 10.2 %. © 2021 Elsevier Ltd
  •  
23.
  • Cehlin, Mathias, et al. (author)
  • Numerical modeling of a complex diffuser in a room with displacement ventilation
  • 2010
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 45:10, s. 2240-2252
  • Journal article (peer-reviewed)abstract
    • A micro/macro-level approach (MMLA) has been proposed which makes it possible for HVAC engineers to easily study the effect of diffuser characteristics and diffuser placement on thermal comfort and indoor air quality. In this article the MMLA has been used to predict the flow and thermal behavior of the air in the near-zone of a complex low-velocity diffuser. A series of experiment has been carried out to validate the numerical predictions in order to ensure that simulations can be used with confidence to predict indoor airflow. The predictions have been performed by means of steady Reynolds Stress Model (RSM) and the results have good agreement both qualitatively and quantitatively with measurements. However, measurements indicated that the diffusion of the velocity and temperature was to some extent under-predicted by the RSM, which might be related to high instability of the airflow close to the diffuser. This effect might be captured by employing unsteady RSM. The present study also shows the importance of detailed inlet supply modeling in the accuracy of indoor air prediction.
  •  
24.
  • Chen, Ailu, et al. (author)
  • Indoor and outdoor particles in an air-conditioned building during and after the 2013 haze in Singapore
  • 2016
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 99, s. 73-81
  • Journal article (peer-reviewed)abstract
    • Particles released from biomass burning can contribute to severe air pollution. We monitored indoor and outdoor particles in a mechanically ventilated and air-conditioned building during and after the 2013 haze event in Singapore. Continuous monitoring of time-and size-resolved particles in the diameter range 0.01–10 μm was conducted for two weeks in each sampling campaign. During the haze event, the averaged size-resolved outdoor particle volume concentrations (dV/d(logDp)) for diameters larger than 0.3 μm were considerably higher than those during the post-haze days (9–185 μm3 cm−3versus 1–35 μm3 cm−3). However, the average number concentration of particles with diameters in the range 10–200 nm was substantially lower on the hazy days than on the post-haze days (11,400 to 14,300 particles cm−3 for hazy days, versus an average of 23,700 particles cm−3 on post-haze days). The building mechanical ventilation system, equipped with MERV 7 filters, attenuated the penetration and persistence of outdoor particles into the monitored building. Indoor particle concentrations, in the diameter ranges 0.3–1.0 μm and 1.0–2.5 μm, closely tracked the corresponding patterns of outdoor particle concentrations. For particles in the size range 0.01–1.0 μm, the size-resolved mean indoor/outdoor (I/O) ratios were in the range 0.12–0.65 with the highest mean I/O ratio at 0.3 μm (0.59 in AC on mode and 0.64 in AC off mode). The air conditioning and mechanical ventilation system with MERV 7 filters provided low single-pass removal efficiency (less than ∼ 30%) for particles with diameters of 0.01–1.0 μm. During the haze, for particles larger than ∼0.2 μm, lower I/O ratios and higher removal efficiencies occurred with the air conditioning operating as compared to with mechanical ventilation only. This observation suggests the possibility of particle loss to air conditioning system surfaces, possibly enhanced by thermophoretic or diffusiophoretic effects.
  •  
25.
  • Chen, Huijuan, et al. (author)
  • Computational investigation on the factors influencing thermal comfort for impinging jet ventilation
  • 2013
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 66, s. 29-41
  • Journal article (peer-reviewed)abstract
    • Impinging jet ventilation (IJV) has been proposed to achieve an effective ventilation of an occupied zone in office and industrial buildings. For IJV systems, draught discomfort is the issue of most concern since it supplies cooled air directly to the occupied zone. This study investigated a number of factors influencing draught discomfort and temperature stratification in an office environment equipped with IJV. The factors considered were: shape of air supply device, discharge height, supply airflow rate and supply air temperature. The Response Surface Methodology (RSM) was used to identify the level of the significance of the parameters studied, as well as to develop the predictive models for the local thermal discomfort. Computational fluid dynamics (CFD) was employed to perform a set of required studies, and each simulation condition was determined by the Box – Behnken design (BBD) method. The results indicated that at a low discharge height, the shape of air supply device had a major impact on the flow pattern in the vicinity of the supply device because of the footprint from impinging jet, which consequently affected the draught risk level in the occupied zone. A square-shaped air supply device was found to result in lower overall draught discomfort than rectangular and semi-elliptic shapes. The RSM analysis revealed that the supply airflow rate had a significant impact on the draught discomfort, while the shape of air supply device and discharge height had moderate effects. The temperature stratification in the occupied zone was mostly influenced by the supply air temperature within the range studied.
  •  
26.
  • Chen, Huijuan, et al. (author)
  • Investigation on the flow and thermal behavior of impinging jet ventilation systems in an office with different heat loads
  • 2013
  • In: Building and Environment. - Oxford : Elsevier. - 0360-1323 .- 1873-684X. ; 59, s. 127-144
  • Journal article (peer-reviewed)abstract
    • This paper presents the flow and temperature field within an office using impinging jet ventilation (IJV) under different heat loads ranging from 17 to 65 W per square meter floor area. The measurement was carried out in a full-scale test room to verify the reliability of three turbulence models, i.e., the RNG k-epsilon, SST k-omega and (nu(2)) over bar - f models. It is found that all the tested models show good agreements with measurements, while the (nu(2)) over bar - f model shows the best performance, especially on the overall temperature prediction. less thanbrgreater than less thanbrgreater thanThe (nu(2)) over bar - f model is used further to investigate a number of important factors influencing the performance of the IJV. The considered parameters are: cooling effect of chilled ceiling, external heat load as well as its position, number of occupants and supplied air conditions. The interaction effect of chilled ceiling and heat sources results in a complex flow phenomenon but with a notable feature of air circulation. The appearance and strength of the air circulation mainly depends on the external heat load on window and number of occupants. It is found that with higher external heat load on window (384 W and 526 W), the air circulation has a strong tendency towards the side wall in the opposite direction to occupant, while with lower power on window (200 W) the air circulation has a strong tendency in the center of the room and extends to a larger area. When two occupants are present, two swirling zones are formed in the upper region. The effects of air circulation consequently alter the temperature field and the level of local thermal comfort.
  •  
27.
  • Chen, Huijuan, et al. (author)
  • Numerical investigation of the flow behavior of an isothermal impinging jet in a room
  • 2012
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 49, s. 154-166
  • Journal article (peer-reviewed)abstract
    • The impinging jet concept has been proposed as a new ventilation strategy for use in office and industrial buildings. The present paper reports the mean flow field behavior of an isothermal turbulent impinging jet in a room. The detailed experimental study is carried out to validate the numerical simulations, and the predictions are performed by means of the RNG k-ε and SST k-ω model. The comparisons between the predictive results and the experimental data reveal that both of the tested turbulence models are capable of capturing the main qualitative flow features satisfactorily. It is found that the predictions from the RNG k-ε model predicts slightly better of the maximum velocity decay as jet approaching the floor, while the SST k-ω model accords slightly better in the region close to the impingement zone. Another important perspective of this study is to investigate the influence of different flow and configuration parameters such as jet discharge height, diffuser geometry, supply airflow rate and confinement from the surrounding environment on the impinging jet flow field with the validated model. The obtained data are presented in terms of the jet dimensionless velocity distribution, maximum velocity decay and spreading rate along the centerline of the floor. The comparative results demonstrate that all the investigated parameters have certain effects on the studied flow features, and the diffuser geometry is found to have the most appreciable impact, while the supply airflow rate is found to have marginal influence within the moderate flow range. 
  •  
28.
  • Chen, Huijuan, et al. (author)
  • Numerical investigation of ventilation performance of different air supply devices in an office environment
  • 2015
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 90, s. 37-50
  • Journal article (peer-reviewed)abstract
    • The aim of this study was to compare ventilation performance of four different air supply devices in an office environment with respect to thermal comfort, ventilation efficiency and energy-saving potential, by performing numerical simulations. The devices have the acronyms: Mixing supply device (MSD), Wall confluent jets supply device (WCJSD), Impinging jet supply device (IJSD) and Displacement supply device (DSD). Comparisons were made under identical set-up conditions, as well as at the same occupied zone temperature of about 24.2°C achieved by adding different heat loads and using different air-flow rates. Energy-saving potential was addressed based on the air-flow rate and the related fan power required for obtaining a similar occupied zone temperature for each device. Results showed that the WCJSD and IJSD could provide an acceptable thermal environment while removing excess heat more efficiently than the MSD, as it combined the positive effects of both mixing and stratification principles. This benefit also meant that this devices required less fan power than the MSD for obtaining equivalent occupant zone temperature. The DSD showed a superior performance on heat removal, air exchange efficiency and energy saving to all other devices, but it had difficulties in providing acceptable vertical temperature gradient between the ankle and neck levels for a standing person. 
  •  
29.
  • Chen, L., et al. (author)
  • Numerical investigations of wind and thermal environment in 2D scaled street canyons with various aspect ratios and solar wall heating
  • 2021
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 190
  • Journal article (peer-reviewed)abstract
    • Optimizing urban ventilation is an effective way to improve urban air quality and thermal environment. For this purpose, under the validation of wind-tunnel experiments, flow regimes and micro thermal environment in typical reduced-canyon models with aspect ratios (AR) of 1.1, 2.4, 4 and 5.67 were investigated by CFD simulations using periodic boundary condition. ANSYS Fluent 15.0 with a solar ray tracing model and radiation model was performed to numerically study turbulence characteristics with wind-driven force and solar-heating conditions. Results revealed that, with wind-driven condition, a clockwise vortex existed in normal and deep street canyon (AR = 1.1 and 2.4) while two counter-rotating vortices appeared in extremely deep canyon (AR = 4 and 5.67). Moreover, different turbulence structures and air temperature distribution existed in canyons with different solar-heating conditions. When the leeward wall or ground was heated, the pedestrian-level velocity increased and street ventilation was strengthened compared to wind-driven condition for all AR values. Particularly, the single main vortex was strengthened (AR = 1.1 and 2.4), and the two-vortex structure in extremely deep canyons (AR = 4 and 5.67) changed to single-vortex structure. When the windward wall was heated, the clockwise main vortex at AR = 1.1 and 2.4 was deformed, and a new sub vortex gradually appeared near street bottom. Furthermore, at AR = 4 and 5.67, windward solar heating destroyed the two-vortex structure and slightly improved pollutant dilution capacity. This work implied that extremely deep street design with weak pedestrian-level ventilation should be avoided. It also provides a meaningful reference for urban planning.
  •  
30.
  • Chen, Lan, et al. (author)
  • The impacts of building height variations and building packing densities on flow adjustment and city breathability in idealized urban models
  • 2017
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 118, s. 344-361
  • Journal article (peer-reviewed)abstract
    • Improving city breathability has been confirmed as one feasible measure to improve pollutant dilution in the urban canopy layer (UCL). Building height variability enhances vertical mixing, but its impacts remain not completely explored. Therefore, both wind tunnel experiments and computational fluid dynamic (CFD) simulations are used to investigate the effect of building height variations (six height standard deviations σH = 0%–77.8%) associated to building packing densities namely λp/λf = 0.25/0.375 (medium-density) and 0.44/0.67 (compact) on city breathability. Two bulk variables (i.e. the in-canopy velocity (UC) and exchange velocity (UE)) are adopted to quantify the horizontal and vertical city breathability respectively, which are normalized by the reference velocity (Uref) in the free flow, typically set at z = 2.5H0 where H0 is the mean building height. Both flow quantities and city breathability experience a flow adjustment process, then reach a balance. The adjustment distance is at least three times longer than four rows documented in previous literature. The medium-density arrays experience much larger UC and UE than the compact ones. UE is found mainly induced by vertical turbulent fluxes, instead of vertical mean flows. In height-variation cases, taller buildings experience larger drag force and city breathability than lower buildings and those in uniform-height cases. For medium-density and compact models with uniform height, the balanced UC/Uref are 0.124 and 0.105 respectively, moreover the balanced UE/Uref are 0.0078 and 0.0065. In contrast, the average UC/Uref in height-variation cases are larger (115.3%–139.5% and 125.7%–141.9% of uniform-height cases) but UE/Uref are smaller (74.4%–79.5% and 61.5%–86.2% of uniform-height cases) for medium-density and compact models. 
  •  
31.
  • Cheng, Hong, et al. (author)
  • Home environment exposure and sick building syndrome (SBS) symptoms among adults in southern China : Health associations in 2010 and 2019
  • 2024
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 248
  • Journal article (peer-reviewed)abstract
    • We studied time trends in home environment and sick building syndrome (SBS) symptoms in a repeat study in five cities in southern China. Moreover, we studied associations between home environment exposure and SBS symptoms. Parents from randomly selected day care centers were invited. One parent per family answered a questionnaire on the home environment and their own SBS symptoms. Data collection was performed in two surveys in 2010 and 2019 (27,292 participants in 2010 and 32,073 in 2019). We used two-level logistic regression to analyze health associations. Asthma decreased from 1.7% to 1.5% (P < 0.05) but allergic rhinitis increased from 6.5% to 16.4% (P < 0.001). All SBS symptoms decreased from 2010 to 2019 (all P < 0.001). Most aspects of the home environment improved from 2010 to 2019 but there were less cleaning, more cats, dogs, and urbanization in 2019. Redecoration, new furniture, and pests were associated with most types of SBS symptoms, similarly in 2010 and 2019. Environmental tobacco smoke (ETS) was associated with SBS symptoms in 2019 only. In conclusion, prevalence of SBS symptoms among young parents in southern China decreased from 2010 to 2019 but allergic rhinitis increased. Cockroaches, rats, mice, mosquitoes or flies can be consistent biological risk factors for SBS symptoms. Redecoration, buying new furniture and traffic air pollution are other risk factors for SBS symptoms. Daily cleaning, frequently putting bedding to sunshine, and having a fan in the bathroom can be protective factors. ETS is an emerging risk factor for SBS symptoms.
  •  
32.
  •  
33.
  • Cheng, Xiaogang, et al. (author)
  • A pilot study of online non-invasive measuring technology based on video magnification to determine skin temperature
  • 2017
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 121, s. 1-10
  • Journal article (peer-reviewed)abstract
    • Much attention was paid on human centered design strategies for environmental control systems of indoor built environments. The goal is to achieve thermally comfortable, healthy and safe working or living environments in energy efficient manners. Normally building Heating, Ventilation and Air Conditioning (HVAC) systems have fixed operating settings, which can't satisfy human thermal comfort requirements under transient and non-uniform indoor thermal environments. Therefore, human thermal physiology signal such as skin temperature, which can reflect human body thermal sensation, has to be measured over time. Several trials have been performed by minimizing measuring sensors such as i-Button and mounting measuring sensors into wearable devices such as glasses. Infrared thermography technology has also been tried to achieve non-invasive measurements. However, it would be much more convenient and feasible if normal computer camera could record images, which could be used to obtain human thermal physiology signals. In this study, skin temperature of hand back, which has a high density of blood vessels and is normally not covered by clothing, was measured by i-button sensors. Images recorded by normal camera were amplified to analyzing skin temperature variation, which are impossible to see with naked eyes. The agreement between i-button sensor measuring results and image magnification results demonstrated the possibility of non-invasive measuring technology by image magnification. Partly personalized saturation-temperature model (T = 96.5 × S + bi) can be used to predict skin temperatures for young East Asia females.
  •  
34.
  • Cho, Y-J, et al. (author)
  • Theoretical and experimental investigation of wall confluent jets ventilation and comparison with wall displacement ventilation
  • 2008
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 43:6, s. 1091-1100
  • Journal article (peer-reviewed)abstract
    • This paper reports CFD and experimental results of the characteristics of wall confluent jets in a room. The results presented show the behaviour of wall confluent jets in the form of velocity profiles, the spreading rate of jets on the surface, jets decay, etc. The empirical equations derived are compared with other types of air jets. In addition, the flow in wall confluent jets is compared with the flow in displacement ventilation supply, with regards to the vertical and horizontal spreading on the floor. It is concluded that the jet momentum of wall confluent jets can be more conserved than other jets. Thus, wall confluent jets have a greater spread over the floor than displacement flow. (C) 2007 Elsevier Ltd. All rights reserved.
  •  
35.
  • Choi, Jieun, et al. (author)
  • Associations between building characteristics and children's allergic symptoms : A cross-sectional study on child's health and home in Seoul, South Korea
  • 2014
  • In: Building and Environment. - : Pergamon Elsevier. - 0360-1323 .- 1873-684X. ; 75, s. 176-181
  • Journal article (peer-reviewed)abstract
    • A cross-sectional study on the home environment and asthma and allergy in children was carried out among children 1-8 years old in Seoul, South Korea from 2009 to 2010. Questionnaires were distributed to 5107 parents through daycare centers and kindergartens; 2755 parents responded, a response rate of 54%. Seven percent and 23% of children were reported to have doctor-diagnosed asthma and hay fever, respectively. A majority (57%) of the families reported having PVC flooring in child's or parents' bedroom. More than 96% of homes used a floor heating system. PVC was used more often as a floor covering in single family houses than in apartments (67% vs. 49%, p < 0.001). PVC flooring was significantly associated with eczema in the previous 6 months (AOR 1.54,95% Cl 1.13-2.09) when adjusted for gender, age, family allergy, socioeconomic status and environmental tobacco smoke. Older buildings tended to have dampness problems, and, consequently, were positively correlated with the prevalence of wheeze. Floor moisture significantly increased the association between PVC and symptoms of wheezing (AOR 2.57, 95% Cl 1.36-4.82) and eczema (AOR 1.97, 95% Cl 1.18-3.28). Apartments without mechanical ventilation in bedrooms were associated with a slight increase in asthma and allergy among children. This study suggests that building characteristics and home exposure can partly explain recent increases in asthma and allergy among children in Seoul. (c) 2014 Elsevier Ltd. All rights reserved.
  •  
36.
  • Choonya, Gasper, et al. (author)
  • Experimental investigations of flow and thermal behavior of wall confluent jets as a heating device for large-space enclosures
  • 2023
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 236
  • Journal article (peer-reviewed)abstract
    • The study aimed to explore the effects of inlet air temperature, outdoor air temperature, inlet bulk velocity, and the number of nozzles on wall confluent jets (WCJ) propagating along an external cold wall in a large space enclosure such as a greenhouse. A combination of experimental study and Response surface methodology has been used to predict the flow and thermal behavior of the WCJ for the studied cases. Box-Behnken design was used to determine the case matrix for four of the above-mentioned vital variables for non-isothermal cases. The experimental study employed constant current anemometers to measure the velocity and temperature of the WCJ. Results showed that the WCJ attached to the wall under both isothermal and non-isothermal conditions. This flow behavior suggests that the WCJ can be used to heat the external facades of large-space enclosures. All the stated variables were critical to the decay factor and decay rate of maximum velocity, albeit at varying levels. The velocity decayed faster with an increase in the inlet bulk velocity and outdoor air temperature. It also decayed faster as the number of nozzles and inlet air temperature decreased. The external wall surface temperature and the wall-heating effect increased as the momentum of the jet increased. The surface temperature on the external wall was most influenced by the inlet air temperature and least by the number of nozzles. Correlations of the second-order polynomial for the Response surface models that estimate the rate of velocity decay and temperature on the external wall were obtained.
  •  
37.
  • Chraibi, Sanae, et al. (author)
  • Satisfying light conditions: a field study on perception of consensus light in Dutch open office environments
  • 2016
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 105, s. 116-127
  • Journal article (peer-reviewed)abstract
    • Workplace innovation has been changing the European office landscape into mostly open spaces, where enhanced interaction between people is combined by efficient use of space. However, challenges are found in offering individual preferred conditions in these multi-user spaces, especially when dealing with shared systems.Previous studies clearly show the benefits of personal control as a means to achieve individual preferred lighting. Most of these benefits were demonstrated in private offices or situations where users have a “personal” light source.Lighting systems in open offices are often designed as a regular grid of luminaires to deliver uniform lighting. This often results in a luminaire grid that does not match the desk arrangement, making it challenging to offer personal lighting controls. By grouping luminaires, users could be offered consensus control. The question is whether consensus control brings advantages rather than disadvantages.This paper presents the results of a field study evaluating consensus light control in an open office 14 users experienced a reference no-control condition and a condition with control over a zone of luminaires. Data was collected by objective measurements as well as subjective surveys and interviews.This study shows that consensus control in an open office improves satisfaction of individual users with the light quantity and quality. Even though the controllable light is shared, consensus among users results in an improved lighting environment for the majority of users. Selected illuminances in the condition with controls were on average lower than in the reference condition, resulting in lower energy usage by lighting.
  •  
38.
  • Chung, Juyeon, et al. (author)
  • Returning and net escape probabilities of contaminant at a local point in indoor environment
  • 2017
  • In: Building and Environment. - : Elsevier Ltd. - 0360-1323 .- 1873-684X. ; 125, s. 67-76
  • Journal article (peer-reviewed)abstract
    • The quantified recirculation of a contaminant in a local domain is an essential property of the ventilation efficiency in a room. The returning probability of a contaminant (α) generated in a local domain and its net escape probability (NEP) are essential information for understanding the structure of the contaminant concentration distribution in a room and for controlling the indoor air quality. Here, we propose the fundamental definitions of α and NEP and discuss their potential relation with the net escape velocity (NEV) concept. NEP is defined at a local point and/or local domain as the probability that a contaminant is exhausted directly through an exhaust outlet and does not re-circulate to the target local point/domain again. In a computational fluid dynamics (CFD) simulation, the minimum local domain in a room corresponds to the control volume (C.V.) of discretization; hence, NEP in a C.V. is assumed as the probability in a point without volume. In this study, the calculation results of α, NEP, and NEV distributions in a simple two-dimensional model room and a three-dimensional room with push-pull type ventilation system are demonstrated and discussed.
  •  
39.
  • Czemiel Berndtsson, Justyna (author)
  • Experiences from the implementation of a urine separation system: Goals, planning, reality
  • 2006
  • In: Building and Environment. - : Elsevier BV. - 1873-684X .- 0360-1323. ; 41:4, s. 427-437
  • Journal article (peer-reviewed)abstract
    • Over the last decade it has been ever increasing interest in developing alternative sanitary systems, which would be more sustainable than a conventional one is. In Sweden urine separation has been considered a promising approach towards increasing recycling of wastewater nutrients. Full scale trials are carried out and examined. This paper presents a study on implementation of urine separation system in urban environment. Technical and non-technical aspects of system performance are evaluated; system's interference with existing infrastructure is examined. Benefits and losses connected to urine separation system are analysed not only from environmental perspective but also system's owner point of view. (C) 2005 Elsevier Ltd. All rights reserved.
  •  
40.
  • Danielski, Itai, et al. (author)
  • Heated atrium in multi-storey apartment buildings, a design with potential to enhance energy efficiency and to facilitate social interactions
  • 2016
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 106, s. 352-364
  • Journal article (peer-reviewed)abstract
    • The design concept of conditioned atria gains increasing popularity in commercial and service buildings all over the world, but is still not a common building design in the residential sector. This study investigates the potential of such design in residential buildings in Nordic climates as means to enhance both energy efficiency as well as social interaction among residents. Energy modelling was used to compare energy efficiency among designs of residential buildings with and without atrium and to identify important design parameters. Social interaction was analysed, based on a survey evaluating the perception of residents living in an existing multi-storey apartment building designed with a heated atrium in the north of Sweden.The results show that heated atrium in Nordic climates have a potential to reduce the total final energy demand while at the same time increase the conditioned space of the building. To positively impact energy efficiency, the atrium should fulfil three requirements: (i) it should be designed to reduce the shape factor for the whole building; (ii) it should have the minimum glazed area that comply with the building requirements concerning natural light and visual comfort; and (iii) adjustable solar shading should be installed in the atrium’s façades to avoid unwanted overheating. The survey results indicate that the additional space created by the atrium has a potential to facilitate and promote social interaction among residents and to increases a sense of neighbourliness and belongingness, which are often discussed as important parameters in relation to social sustainability.
  •  
41.
  • de Bakker, Christel, et al. (author)
  • Occupancy-based lighting control in open-plan office spaces : A state-of-the-art review
  • 2017
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 112, s. 308-321
  • Journal article (peer-reviewed)abstract
    • Lighting accounts for a significant amount of electrical energy consumption in office buildings, up to 45% of the total consumed. This energy consumption can be reduced by as much as 60% through an occupant-dependent lighting control strategy. With particular focus on open-plan offices, where the application of this strategy is more challenging to apply due to differences in individual occupancy patterns, this paper covers (1) to which extent individual occupancy-based lighting control has been tested, (2) developed, and (3) evaluated. Search terms were defined with use of three categories, namely ‘occupancy patterns’, ‘lighting control strategy’, and ‘office’. Relevant articles were selected by a structured search through key online scientific databases and journals. The 24 studies identified as eligible were evaluated on six criteria: (1) study characteristics, (2) office characteristics, (3) lighting system characteristics, (4) lighting control design, (5) post-occupancy evaluation, and (6) conclusions, and this was used to answer the research questions. It was concluded that the strategy has not been tested yet with field studies in open-plan offices, but that it needs further development before it can be applied in these type of offices. Although lighting currently tends to be controlled at workspace level, many aspects of the strategy can be further developed; there is potential to further increase energy savings on lighting within open-plan office spaces. Individual occupancy-based lighting control requires further validation, focussing on the factors influencing its energy savings, on its cost effectiveness, and on its acceptability for users.
  •  
42.
  • Du, Chenqiu, et al. (author)
  • Grey image recognition-based mold growth assessment on the surface of typical building materials responding to dynamic thermal conditions
  • 2023
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 243
  • Journal article (peer-reviewed)abstract
    • Mold growth on building materials poses a threat to both the building structural integrity and occupants' well-being. However, it is generally studied under suitable conditions in laboratory; the assessment is based on visual inspection but lacks an objective criterion. This research explored the effects of simulated dynamic thermal conditions on mold growth on three typical building materials artificially contaminated with Aspergillus niger spores. Test specimens were assessed based on a developed digital image-based method, where image seg-mentation, processing, and greyscale recognition via the OpenCV visual library were introduced. The results showed that the high temperature-high humidity condition in a 24-h cyclic change facilitated mold growth on the surfaces of three materials, especially for gypsum board, with an identified area proportion of 1.13% on the 80th day. This was consistent with the changes of the counted number of mold colonies, and no significant differences were found among the gypsum board, latex paint, and wallpaper. The growth extents of mold spores were objectively evaluated by the mean greyscale values; the values decreased gradually with time, and the decrements were different compared high-temperature to low-temperature conditions. The mold growth models were developed, where the area proportion of mold growth was linearly related to the counted colonies and greyscale values under different material surfaces. This novel grey image recognition-based method provides an accurate means of evaluating mold growth abilities and extents, overcoming the inaccuracy of visual observa-tion. The findings have significant implications for visual inspection, mold prediction, and building management.
  •  
43.
  • Du, Chenqiu, et al. (author)
  • Home dampness/mold(D/M) improvement in children's residences over the past decade in China-a comparison of repeated surveys in 2010 and 2019
  • 2021
  • In: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 205
  • Journal article (peer-reviewed)abstract
    • There is mounting evidence that exposure to household dampness/mold (D/M) is the cause of respiratory, allergic diseases for children. While few research focuses on the effects caused by building environment changes, from a longitudinal investigation perspective, especially for China experiencing a rapid development in recent years. This study aimed to explore the changes of D/M in Chinese homes over the past 10 years and identify the impacts of climate, building energy efficiency and residents' behaviors. The cross-sectional surveys were repeatedly conducted in children' residences in 2010 (Period I) and 2019 (Period II), among Taiyuan, Urumqi in northern China, and Nanjing, Shanghai, Wuhan, Changsha, Chongqing in southern China. Finally, 23465 children in Period I and 34720 children in Period II were involved, with no changes of residences since birth. The results showed that the proportions for reported D/M indicators were significantly reduced in Period II: e.g., 93.8% and 84.1% residents respectively answered no visible mold spots and damp stains in current residences, compared to only 78.3% and 62.2% in Period I. Southern homes accounted for high proportions for D/M indicator occurrences; warm-humid climate, annual higher precipitation and lower sunshine hours, etc., exacerbated the indoor D/M exposure risks. While residents' behaviors like ventilation, airing quilt/beddings, regular cleaning ameliorated the reported D/M significantly. The findings, from a temporal and spacious dimension perspective, advance our understanding of indoor D/M changes, precisely improvement in children' homes over the past 10 years, benefiting to promote indoor air quality standards in China.
  •  
44.
  • Einberg, Gery, et al. (author)
  • CFD modelling of an industrial air diffuser : predicting velocity and temperature in the near zone
  • 2005
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 40:5, s. 601-615
  • Journal article (peer-reviewed)abstract
    • This article describes experimental and modelling results from CFD simulation of an air diffuser for industrial spaces. The main objective of this paper is to validate a manufacturer model of the diffuser. In the air diffuser, the low velocity part is placed on top of a multi-cone diffuser in order to increase airflow rates and maximize the cooling capacity of a single diffuser unit. This kind of configuration should ensure appropriate performance of industrial air diffusers, which is discussed briefly at the end of the article. The paper illustrates the importance of a simulation model jointly with the manufacturer's product model and the grid layout near the ventilation device to achieve accurate results. Parameters for diffuser modelling were adapted from literature and manufacturer's product data. Correct specification of diffuser geometry and numerical boundary conditions for CFD simulations are critical for prediction. The standard k-epsilon model was chosen to model turbulence because it represents the best-known model utilized and validated for air diffuser performance. CFD simulations were compared systematically with data from laboratory measurements; air velocity was measured by ultrasonic sensors. Results show that CFD simulation with a standard k-epsilon model accurately predicts non-isothermal airflow around the diffuser. Additionally, smoke tests revealed that the flow around the diffuser is not completely symmetrical as predicted by CFD. The cause of the observed asymmetry was not identified. This was the main reason why some simulation results deviate from the measured values.
  •  
45.
  • Ekim, Zeynep, et al. (author)
  • Assessments of users' interactions with energy-efficient solutions: A systematic review
  • 2023
  • In: Building and Environment. - 1873-684X. ; 115
  • Research review (peer-reviewed)abstract
    • Despite new energy-efficient technologies in buildings, discrepancies between predicted and actual energy use continue to occur, mainly due to the complexity and variability of users' behaviour(s). Users' interactions with energy-efficient solutions need to be studied holistically to better understand the complexity of their behaviour. This systematic literature review was conducted to identify whether and to what extent researchers have considered the role of users, users' behaviour and behavioural drivers in interactions with buildings' energy-efficient solutions following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The review evaluated how focus (the studied context and users' interactions) and tools (the methods and theoretical background) were applied in the selected studies. The findings show that the majority of the studies neglected in-depth investigations of users' behavioural drivers. Only few studies considered psychological factors and applied related theories to identify drivers of energy-use behaviours. Behavioural drivers varied depending on types of energy-use behaviour, user and environmental characteristics. This review points to the need to further investigate the role of users in the interactions with energy-efficient solutions holistically and suggests possible implications for defining effective energy-saving strategies. Overall, the result of the reviewed papers was not consistent with affirming energy efficiency in energy-efficient buildings and therefore, emphasises a need for detailed analyses of users’ behavioural drivers together with physical and social contexts to reduce the mismatch between predicted and actual energy use.
  •  
46.
  • Elvsen, Per-Ake, et al. (author)
  • Buoyant jet in a ventilated room : Velocity field, temperature field and airflow patterns analysed with three different whole-field methods
  • 2009
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 44:1, s. 137-145
  • Journal article (peer-reviewed)abstract
    • The instantaneous velocity field and temperature field were measured and file airflow patterns visualised close to a diffuser for displacement ventilation. Since the low-velocity diffuser was located above the floor and the inlet air temperature was below the room temperature, the flow was governed by both momentum and buoyancy forces. The data were recorded with whole-field measuring techniques, particle streak velocimetry (PSV), particle image velocimetry (PIV) and infrared thermography (IR), in conjunction with a low thermal mass screen. The environment is very complex, supply of buoyant air with a commercial supply terminal with 20 nozzles pointing in different directions. which makes it difficult to use point-measuring techniques or computational fluid dynamics (CFD). The aim was twofold: (a) to explore what kind of information can be derived Front whole-field measurement techniques in this context and (b) to investigate the trajectory of the flow discharged into the room and the entrainment of the flow.
  •  
47.
  • Erlandsson, M, et al. (author)
  • Environmental assessment of rebuilding and possible performance improvements effect on a national scale
  • 2004
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 39:12, s. 1453-1465
  • Journal article (peer-reviewed)abstract
    • The paper deals with improvements on environmental significant activities related to the life supporting function "building and housing", using life cycle assessment (LCA). In the calculation, back-casting technique is utilised and implies to a future scenario, based on known technology. Besides heating, waste water treatment is a significant issue, according to the definition of building and housing function practised. The main conclusions from the assessment are that rebuilding is an environmentally better choice than the construction of a new building, if the same essential environmentally related functional performance is reached. Furthermore, the case study and the national estimates performed prove that the potential environmental impact can be reduced by about 70% for the heating service and 75% for the waste water system, if the suggested measures are performed.
  •  
48.
  • Erlandsson, Martin, et al. (author)
  • Environmental assessment of rebuilding and possible performance improvements effect on a national scale
  • 2005
  • In: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 40:11, s. 1459-1471
  • Journal article (peer-reviewed)abstract
    • This paper deals with improvement on environmental significant activities related to the life supporting function "building and housing", using life cycle assessment. In the calculation, back-casting technique is utilised and implies to a future scenario, based on known technology. Besides heating, wastewater treatment is a significant issue, according to the definition of building and housing function practised. The main conclusions from the assessment are that rebuilding is an environmentally better choice than the construction of a new building, if the same essential environmentally related functional performance is achieved. Furthermore, the case study and the national estimates performed prove that the potential environmental impact can be reduced by about 70% for the heating service and 75% for the wastewater system, if the suggested measures are performed.
  •  
49.
  • Falk, Jörgen, et al. (author)
  • Investigation of a simple approach to predict rainscreen wall ventilation rates for hygrothermal simulation purposes
  • 2014
  • In: Building and Environment. - : Elsevier BV. - 1873-684X .- 0360-1323. ; 73:March, s. 88-96
  • Journal article (peer-reviewed)abstract
    • Hygrothermal simulation programs are commonly used by design engineers to analyse moisture performance of building envelopes. For ventilated assemblies, programs typically require the user to enter cavity ventilation rates. If such input data are not prepared on physical grounds, it can impair the quality of the simulation results. In earlier papers: (1) estimations of ventilation rates in experimental walls based on cavity air velocity measurements; (2) comparative calculations based on monthly and annual tabular climate data, a simple driving force model and models of cavity airflow and heat balance, have been presented. In this study, the models and hourly climate field data were used to perform calculations of transient cavity ventilation rates for comparison with previous experimental results. For 13 different time periods extending from 24 to 91 hours, the calculated average ventilation rates were within or very close to the experimentally estimated limits for the ventilation rate. Additionally, the calculations captured the temporal variability and the physical cause of ventilation airflow in the cavities reasonably well. The applied calculation methodology can be developed into a user friendly approach to estimate realistic ventilation rate input data for hygrothermal purposes. Limitations and possible improvements of the methodology are discussed. The influence of the accuracy and resolution of the ventilation rate input data in simulations is demonstrated in a case study.
  •  
50.
  • Falk, Jörgen, et al. (author)
  • Ventilated rainscreen cladding: A study of the ventilation drying process
  • 2013
  • In: Building and Environment. - : Elsevier BV. - 1873-684X .- 0360-1323. ; 60, s. 173-184
  • Journal article (peer-reviewed)abstract
    • The air exchange in rainscreen walls is expected to provide ventilation drying if excess moisture is absorbed in the wall construction. In an earlier paper, we presented a cavity airflow model and measurement based estimations of air change rates (ACH) in south-facing experimental walls. Here, focus is on the ventilation drying process and its practical implications. ACH in the experimental walls were calculated and converted into drying rates at different stages in the drying process. Furthermore, changes in the drying rates due to changes in the cavity design and in the outdoor climate were investigated. The significance of the drying rates was demonstrated in a case study. Findings showed that the cavity design is of major importance for the drying rate if the material adjacent to the cavity is wet over its entire extension. For such extreme cases, a light facade colour, vented horizontal battens and, in particular, a small cavity depth, are adverse factors for the drying rate. As the drying process proceeds and the moisture transport from the material to the cavity air becomes dependent on vapour diffusion, the drying rates for different cavity designs tend to be evened out. If the resistance to vapour flow in the material reaches high levels, a favourable outdoor climate is significantly more important than the cavity design to promote drying. Also for the case where the material adjacent to the cavity initially is only locally wet, findings showed that the cavity design is of minor importance for the drying time. (c) 2012 Elsevier Ltd. All rights reserved.
  •  
Skapa referenser, mejla, bekava och länka
  • Result 1-50 of 230
Type of publication
journal article (227)
research review (3)
Type of content
peer-reviewed (228)
other academic/artistic (2)
Author/Editor
Sandberg, Mats, 1945 ... (20)
Sandberg, Mats (17)
Yang, Bin (16)
Norbäck, Dan (12)
Moshfegh, Bahram (11)
Sadrizadeh, Sasan (11)
show more...
Kobayashi, Tomohiro (10)
Li, Baizhan (9)
Zhang, Xin (8)
Deng, Qihong (8)
Huang, Chen (7)
Zhao, Zhuohui (7)
Yang, Xu (7)
Qian, Hua (7)
Yu, Wei (6)
Olofsson, Thomas, 19 ... (6)
Holmberg, Sture (6)
Mattsson, Magnus, 19 ... (6)
Karimipanah, Taghi, ... (6)
Malmqvist, Tove (6)
Zhang, Yinping (6)
Sun, Yuexia (6)
Wigö, Hans (5)
Glaumann, Mauritz (5)
Isaksson, Tord (5)
Wang, Juan (5)
Aries, Myriam (4)
Mjörnell, Kristina (4)
Kabanshi, Alan (4)
Langer, Sarka, 1960 (4)
Wang, Qian, 1984- (4)
Liu, Jing (4)
Lin, Yuanyuan (4)
Thelandersson, Sven (3)
Cehlin, Mathias (3)
Ameen, Arman, 1976- (3)
Olofsson, Thomas (3)
Wang, Cong (3)
Cehlin, Mathias, Dok ... (3)
Yamasawa, Haruna (3)
Teli, Despoina, 1980 (3)
Eriksson, Ola (3)
Awbi, Hazim, 1946- (3)
Zhang, Xingxing (3)
Johansson, Pernilla (3)
Ekstrand-Tobin, Anni ... (3)
Afshari, Alireza (3)
Psomas, Theofanis, 1 ... (3)
Cai, Jiao (3)
Du, Chenqiu (3)
show less...
University
University of Gävle (73)
Royal Institute of Technology (70)
Lund University (29)
Umeå University (20)
Uppsala University (19)
Linköping University (18)
show more...
Luleå University of Technology (11)
RISE (10)
Chalmers University of Technology (9)
Jönköping University (6)
IVL Swedish Environmental Research Institute (6)
Högskolan Dalarna (5)
Mälardalen University (4)
Linnaeus University (3)
Örebro University (2)
Mid Sweden University (2)
University of Gothenburg (1)
Malmö University (1)
Karlstad University (1)
Karolinska Institutet (1)
show less...
Language
English (230)
Research subject (UKÄ/SCB)
Engineering and Technology (187)
Medical and Health Sciences (21)
Natural sciences (20)
Social Sciences (5)
Humanities (2)

Year

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Close

Copy and save the link in order to return to this view