| |
Building and Environment (06 March 2010)
Abstract
Tree-shaded outdoors can reduce the heat effect by ameliorating the microclimate and enhancing the human thermal comfort outdoors; for this reason, they are main places for rest, recreation and social activity in Taiwan's cities. Field comfort surveys of 3,839 interviewees were conducted in tree-shaded spaces throughout a year. The aims were to obtain a better understanding of human thermal comfort response outdoors and to propose an adaptive comfort model for tree-shaded spaces. A comfort zone, centering on neutral operative temperature which ...
|
| |
Building and Environment (06 March 2010)
Abstract
Performance of vegetated roofs are investigated in terms of their expected benefits for the building and the urban environment, due to their recognised energy and water management potential scores. A review of related worldwide experiences is reported for comparison purposes. The investigation is here performed within the specific climatic context of the Mediterranean region. Full scale experimental results are provided from two case studies, located in north-west and central Italy, consisting in two fully monitored green roofs on top of public ...
|
| |
Building and Environment (03 March 2010)
Abstract
This paper describes urban wind ventilation mapping, using the concept of “building frontal area index”, and uses the Kowloon peninsula of Hong Kong as an example of a dense, sub-tropical urban environment where ventilation is critical for human health. The frontal area index is calculated for uniform 100m grid cells, based on three dimensional buildings in each cell, for eight different wind directions. The frontal area index is then correlated with a land use map, and the results indicate that high ...
|
| |
Building and Environment (03 March 2010)
Abstract
This paper investigates the energy saving potential of a thermal comfort-controlled office building. A comparative simulation study between the thermal comfort control and conventional thermostatic control is conducted on a building with glass façades where changes in the outdoor temperature and solar radiation over the course of a day affect radiant temperature and thus thermal comfort. To evaluate the thermal performance in the comfort-controlled space, a PMV-based thermal comfort controller, which adjusts the set-point room temperature of the existing thermostatic controller ...
|
| |
Building and Environment (26 February 2010)
Abstract
The dispersion of exhausted pollutants from a building roof stack situated in the wake of a neighbouring tower has been studied using computational fluid dynamics (CFD) with the realizable k-ε turbulence model for closure. Two scales are considered in this work, full-scale (1:1) and wind tunnel scale (1:200). Of primary interest are the distributions of the plume and of the pollutant concentrations on the building roof as well as on the leeward wall of the tower. Two stack heights ...
|
| |
Building and Environment (24 February 2010)
Abstract
Air flow patterns and mean air speeds were studied under laboratory conditions representing a full scale open-plan office. Three basic conditions were tested: summer, spring/autumn and winter. Chilled beams were used to provide cooling, outdoor air supply and air distribution in the room. The heat sources had a notable influence on the flow pattern in the room causing large scale circulation and affecting the direction of inlet jets. The maximum air speed in the occupied zone was higher than the recommendations. ...
|
| |
Building and Environment (23 February 2010)
Abstract
To address the worsening problems of global warming and the urban heat island effect, ecological cities and building environment greening are being promoted in population-dense urban areas domestically and abroad. For example, the Japanese Ministry of Land, Infrastructure, Transport, and Tourism announced the CASBEE-HI (Heat Island) assessment system in 2008 as a response to worsening urban warming and urban heat island effects. The Ministry implemented “Building Space Greening Plans” in Tokyo, Osaka, and other cities, enforcing by law the effective reduction ...
|
| |
Building and Environment (23 February 2010)
Abstract
A two-bed hospital ward with one standing healthcare person and a ceiling-mounted lowimpulse semicircular inlet diffuser is simulated in a full-scale room. Tracer gas is used for simulating gaseous contaminants, and the concentration is measured at different air change rates and different postures of the patients. A textile partition between the beds, which is typical in a hospital ward, is used for protection of the patients in some of the experiments. Three different layouts of return openings are tested. One layout ...
|
| |
Building and Environment (23 February 2010)
Abstract
The total insulation value of a bedding system is a significant factor affecting the neutral temperature in a sleeping thermal environment. This paper reports on a study of developing a mathematical model for predicting the total insulation values of various bedding systems. The factors influencing the total insulation value of a bedding system such as the percentage coverage over a human body, types of bed with mattress and bedding, etc., were included in the model. The predicted total insulation values using ...
|
| |
Building and Environment (20 February 2010)
Abstract
The incorporation of phase change materials (PCMs) in building materials for use as latent heat storage and for potential reduction of energy requirements is an on-going field of study. In this paper, the development and testing of PCM-enhanced cellulose insulation for use in frame walls is presented. Two types of PCMs, paraffin-based and hydrated salt-based, were mixed into loose-fill cellulose insulation at concentrations of 10% and 20% (by the weight of the wallboard) in a 1.22 m x 1.22 m (48 in. x ...
|
| |
Building and Environment (20 February 2010)
Abstract
An experimental approach is used to assess the effect of vegetation on the thermal performance of a vertical greening system, which comprised of turf base vertical planting modules, on an elevated facade wall of a public housing apartment. Despite temperature fluctuations in the various compartments external and internal to a concrete wall, the vegetated cladding reduced interior temperatures and delayed the transfer of solar heat, which consequently reduced power consumption in air conditioning compared with a building envelope with bare concrete. ...
|
| |
Building and Environment (20 February 2010)
Abstract
Heat and mass transfer modelling in building facades with ventilated cavities requires information on the cavity air change rates, which can be a complex function of the building and cavity geometry and the meteorological conditions. This paper applies Reynolds-averaged Navier-Stokes (RANS) CFD to study wind-induced airflow in the narrow (23 mm) ventilated facade cavities of an isolated low-rise building. Both coupled and decoupled simulations are performed. In the coupled simulations, the atmospheric boundary layer wind-flow pattern around the building and the resulting ...
|
| |
Building and Environment (20 February 2010)
Abstract
Calculating the velocity and particle concentration indoor is critical for isolation rooms design. Computational fluid dynamics (CFD) is regarded as a powerful tool aiding in the indoor environment design for isolation rooms by enabling us to predict the velocity and particle concentration distribution in detail. However, CFD method is time consuming and relatively expensive, especially for actual engineering application. So this study proposes a simplified methodology to predict the mean air velocity and particle concentration in the occupied zone of isolation ...
|
| |
Building and Environment (20 February 2010)
Abstract
Understanding the dispersion of contaminants inside buildings is important for improving indoor air quality (IAQ). Detailed information on the dispersion profile within a room is required to design active protection systems and to develop countermeasure strategies against potential threats from particulate based agents. A number of computational fluid dynamics (CFD) codes in the public and commercial domain can simulate contaminant dispersion inside a building. One of the critical boundary conditions required by these CFD codes is a resuspension source term model. ...
|
| |
Building and Environment (19 February 2010)
Abstract
An “exposure reduction effectiveness” index is proposed to quantify the performance of room air cleaners based on their capability of reducing occupants’ exposure to pollutants of interest. The index has advantages over existing index such as CADR. It is applicable to both room average and local breathing zones, and can be used to compare air cleaning with the other two IAQ strategies: ventilation and source reduction. A computational fluid dynamics model is developed and used to assess the effectiveness of a ...
|
| |
Building and Environment (19 February 2010)
Abstract
In modern operating rooms ultraclean air is supplied through the ceiling to prevent bacteria from entering an operating wound and cause infections. Operating lamps can disturb this flow of clean air. In this paper the accuracy of some aspects of the Laminar Flow Index of operating lamps was tested. The disturbance of the airflow was determined for different shapes and sizes of operating lamps in an isothermal situation. To accomplish this, an experimental study and a simulation study of a small ...
|
| |
Building and Environment (19 February 2010)
Abstract
Formaldehyde and volatile organic compounds (VOCs) from the adhesive, flooring, and flooring with adhesive were measured using a desiccator, a 20-L chamber and a field and laboratory emission cell (FLEC). Flooring with an adhesive similar to that used in construction was applied to a floor heating system and an air circulation system, and the surface temperature of the flooring was set to 20°C, 26°C and 32°C. The rate of formaldehyde emission from the flooring was the highest at 32°C using a ...
|
| |
Building and Environment (19 February 2010)
Abstract
This study analyzed the effect of bake-out on reducing VOC emissions and indoor concentrations in a residential housing unit with a radiant floor heating system. The effect of an elevated temperature on VOC emissions from a wallpaper assembly, plywood flooring assembly, and particle board (as an example of furniture material) was investigated in a small-scale chamber. Simultaneously, in the residential housing unit, we measured the VOC emissions from the materials and indoor concentrations in the housing unit that have previously undergone ...
|
| |
Building and Environment (16 February 2010)
|
| |
Building and Environment (13 February 2010)
Abstract
Liquid desiccant regeneration has important effect on performance of a liquid desiccant air conditioning system. Compared with conventional packed regenerator, internally heated regenerator is proposed to achieve better regeneration performance. This study emphasized on both regeneration rate and regeneration thermal efficiency to evaluate the performance of both regenerators. A validated heat and mass transfer model was used to analysis and compare the performance of internally heated and adiabatic regenerators. The results indicated that internally heated regenerator not only could increase the ...
|
| |
Building and Environment (12 February 2010)
Abstract
The spatial distribution of CO 2 level in a classroom carried out in previous field work research has demonstrated that there is some evidence of variations in CO 2 concentration in a classroom space. Significant fluctuations in CO 2 concentration were found at different sampling points depending on the ventilation strategies and environmental conditions prevailing in individual classrooms. However, how these variations are affected by the emitting sources and the room air movement remains unknown. Hence, it was ...
|
| |
Building and Environment (12 February 2010)
Abstract
The dispersion of air pollutant in complex building environment has become of great concern as more and more people live in large and crowded cities. The present work is aimed at investigating the indoor air pollutant dispersion and possible cross-unit contamination with typical high-rise residential building design in Hong Kong. Experiments were performed in a boundary layer wind tunnel for a 1:30 scale model that represented a 10-story residential building in prototype. Tracer gas, simulating exhausted room air, was continuously released ...
|
| |
Building and Environment (10 February 2010)
Abstract
In order to assess the efficiency of buildings or renewable energy systems, simulation software need relevant meteorological files. These weather data are generated thanks to statistical methods. Actually, these methods are derived to treat high quality hourly databases or monthly average of the weather parameters. When only inconsistent hourly database is available for a site, the meteorological file used for the energy simulations must be generated from the monthly averages. This paper deals with a new weather data generation tool, Runeole, ...
|
| |
Building and Environment (08 February 2010)
Abstract
This study investigated the impacts of different diffuse reflectance distributions and well geometries on vertical daylight factors and vertical internally reflected components in atria. Two forms of reflectance distribution patterns of wall surface were examined:horizontal and vertical reflectance band variation. The square atrium models studied have a broader WI range of 0.25 to 2.0, which represents shallow, medium and high atria. Radiance, a powerful package based on backward ray tracing technique, was used for the simulations of vertical daylight levels. The ...
|
| |
Building and Environment (08 February 2010)
Abstract
The partial differential equation (PDE) model is established based on the physical movement of the continuous crowd states, and has a strong dependence on the initial conditions. In addition, some characteristics of large crowd like the phenomena of discontinuous jumping in reality are hard to explain by partial differential equations (PDEs). The catastrophe theory, however, can explain these characteristics. The catastrophe model is based on complex systems, and does not rely on the initial conditions. A catastrophe model is presented in ...
|
| |
Building and Environment (04 February 2010)
Abstract
A performance-based service life design format based on climatic exposure on one hand and “resistance” of materials against mould growth on the other hand, is presented in this paper. A limit state for onset of mould growth is defined as the occurrence of traces of mould observed by microscopy. A dose-response model is proposed by which onset of mould growth can be predicted for an arbitrary climate history of combined relative humidity φ and temperature T . The ...
|
| |
Building and Environment (04 February 2010)
Abstract
This paper presents a literature review of the status of research on indoor antimicrobial control by photocatalytic oxidation (PCO). The review and discussion concentrate on (a) the PCO disinfection mechanisms; (b) different kinetic experiments and models; (c) the dependence of inactivation rate on some key influencing factors; (d) an overview of various PCO reactors and their application performance reported in the literature. Major conclusions of the overview and recommendations for future work include (a) several reaction pathways of PCO antimicrobial process ...
|
| |
Building and Environment (01 February 2010)
Abstract
Most aircraft cabin ventilation designs currently use a 50% mix of fresh and recirculated, filtered air and supply approximately 8-10 l/s per person. In order to make the most efficient use of the air supply at hand, the 50% of cabin air that is exhausted from the aircraft should remove with it as much contaminant from within the cabin as possible. This will thereby reduce cross-contamination among passengers and improve overall air quality. This study examines the use of localized suction ...
|
| |
Building and Environment (29 January 2010)
Abstract
The performance of a coupled system of the Desktop Personalized Ventilation Air Terminal Device (DPV ATD) and desk mounted fans (DMF) was examined in a field environmental chamber. Cooling effect was evaluated using manikin - based equivalent temperature (Teq,), of each of the 26 body segments of a breathing thermal manikin (BTM) and personal exposure effectiveness (PEE) was used as an indicator for effectiveness of ventilation. Computational fluid dynamics (CFD) was used to examine the velocity field generated around BTM to ...
|
| |
Building and Environment (29 January 2010)
Abstract
Despite evidence suggesting conflicting views between practitioners and researchers when it comes to estimating the costs and financial benefits of green buildings, there exists no research work that has attempted to investigate practitioners’ perception, and in particular Canadian practitioners’, of the work conducted by researchers. To fill this gap in the literature, a web-based anonymous survey was administered to 1200 LEED accredited professionals in Canada to assess, among other things, practitioners’ awareness, and confidence in research work assessing the cost premiums, ...
|
| |
Building and Environment (29 January 2010)
Abstract
This study investigated the potential impact of climate change on the heating and cooling (H/C) energy requirements of residential houses in five regional climates varying from cold to hot humid in Australia. Nine General Circulation Models (GCMs) under three carbon emission scenarios were applied to project the local climate. It was found that significant climate change impact on H/C energy requirements may occur within the lifespan of existing housing stock. The total H/C energy requirement of newly constructed 5 star houses ...
|
| |
Building and Environment (28 January 2010)
Abstract
Efficient and rational implementation of building stock CO 2 emission reduction strategies and policies requires the application of comprehensive building stock models that have the ability to: (a) estimate the baseline energy demand of the existing building stock, (b) explore the technical and economic effects of different CO 2 emission reduction strategies over time, including the impact of new technologies, and (c) to identify the effect of emission reduction strategies on indoor environmental quality. The aims of this paper ...
|
| |
Building and Environment (25 January 2010)
Abstract
This study aimed to develop an Artificial Neural Network (ANN)-based advanced thermal control method for creating more comfortable thermal environments in residential buildings. The proposed control method consisted of a thermal control logic framework with four thermal control logics therein, including two predictive and adaptive logics using ANN models, and a system hardware framework. The models were designed to achieve thermal comfort for living areas, taking into account not only air temperature, but also humidity or PMV as a control variable; ...
|
| |
Building and Environment (25 January 2010)
Abstract
The pressure distribution in a vertical exhaust shaft is important in determining the ventilation performances of local exhaust hoods in high-rise buildings. Uneven pressure distribution can cause insufficient exhaust airflows from hood fans, and can cause excessive exfiltration resulting in unwanted noise through any gap openings. There are various system parameters that affect the pressure distribution in a vertical shaft, such as building height, shaft size, roof fan characteristics, concurrent hood fan usage, and outdoor temperature. The objective of this study ...
|
| |
Building and Environment (20 January 2010)
Abstract
Residential highrise building fire of height above 200 m is now a concern in the Far East. Long-term survey study on fire load density indicated that high amount of combustibles over the local upper limit of 1135 MJm −2 used to be stored in residential flats. Wind-induced air flow rates through openings at upper levels of those tall buildings can be very high. Stack effect in areas with large indoor and outdoor temperature differences (such as 14°C indoor and -30oC ...
|
| |
Building and Environment (20 January 2010)
Abstract
Several countermeasures against the prevalence of infectious diseases have recently been issued, and one of them, the ultraviolet germicidal irradiation (UVGI) system, has been carefully considered for building environments especially. Besides experimental methods to evaluate the germicidal performance of upper air UVGI systems, this research introduces two numerical methods using the concept of ventilation performance, and illustrates the methods with a ward model. The first calculates the average residence time of air using the concept of local purging flow rate (L-PFR) ...
|
| |
Building and Environment (15 January 2010)
|
| |
Building and Environment (14 January 2010)
Abstract
In this paper, the results of a study on a hybrid system of nocturnal radiative cooling, cooling coil, and direct evaporative cooling in Tehran have been discussed. During a night, the nocturnal radiative cooling provides required chilled-water for a cooling coil unit. The cold water is stored in a storage tank. During eight working hours of the next day, hot outdoor air is pre-cooled by means of the cooling coil unit and then it enters a direct evaporative cooling unit. In ...
|
| |
Building and Environment (14 January 2010)
Abstract
The study investigated differences in worker satisfaction and perceived job performance regarding privacy, interaction, and acoustic quality issues in personal workspaces between five office types in LEED-certified buildings. It finds that people in high cubicles showed significantly lower satisfaction and job performance in relation to visual privacy and interaction with co-workers than both enclosed private and enclosed shared office types. They also showed significantly lower satisfaction with noise level and sound privacy and lower job performance perceived by acoustic quality than ...
|
| |
Building and Environment (13 January 2010)
Abstract
This paper investigates the effects of occupant gender and age on thermal satisfaction in office environments. The data used for the analyses was collected from 402 sampled occupants and their workstations on 38 floors in 20 office buildings in the U.S. with support from the U.S. General Services Administration. The field measurements include data collection for air temperature, radiant temperature, temperature stratification, relative humidity and air velocity of the sampled workstations. Occupant satisfaction surveys were distributed to each occupant in the ...
|
| |
Building and Environment (11 January 2010)
Abstract
Dispersion of ultrafine particles (less than 0.1 μm) and accumulation mode particles (0.1 to 2.5 μm) remains as an area of major concern to microelectronic and semiconductor industry. A possible means of containing the dispersion of particulate pollutants is to subject them to electrostatic precipitation. The present study is concerned with the dispersion of particles in the presence of an inhomogeneous electric field. The widely accepted drift flux model is used to account for the drift flux induced by the inhomogeneous ...
|
| |
Building and Environment (07 January 2010)
Abstract
Venetian blinds are a common type of shading device and are increasingly operated automatically to overcome the limitations of manual operation. Automated blinds need to be controlled to maximize benefits of daylight in the point of occupant comfort and energy consumption. However, the previous control methods are focused on minimizing negative impacts of daylight, so they might fail to maximize positive impacts of daylight. They may often overpredict a blind's position, resulting in the undesirable blockage of daylight. In this paper, ...
|
| |
Building and Environment, Vol. 45, No. 6. (04 June 2010), pp. 1401-1414.
Abstract
This paper investigates how vegetation, mainly through evapotranspiration, affects the improvement of microclimatic conditions in urban areas and, more specifically, it examines the case for the city of Chania in Crete. The objectives of this study are to examine the bioclimatic role of green areas in urban sites as they affect the thermal comfort of residents, and to study the cross-correlation of factors that participate in this process. To achieve these objectives, we have examined the parameters that contribute to the ...
|
| |
Building and Environment (04 January 2010)
Abstract
Experiments were conducted in a full-scale model office equipped with movable and fixed fire loads to explore the influence of ignition source (movable fire load(s)) conditions on smoke detector and sprinkler actuation. The interior plan dimension is 5.7 m × 4.7 m and the net ceiling height is 3.3 m. Both northeast and southeast wings have a 2.1 m × 0.9 m single door to be opened. Seven fire scenarios (seven different ignited fire load configurations) under natural ventilation were investigated ...
|
| |
Building and Environment (04 January 2010)
|
| |
Building and Environment (04 January 2010)
Abstract
In this study we estimate the air leakage distribution of single-family dwellings in Catalonia and use a statistical analysis of an airtightness database for single-family dwellings in France to identify the building characteristics that have the greatest influence on airtightness. The most significant variables are found to be the structure type, the floor area, the age of the building, the number of stories and the insulation type. A multiple linear regression technique is then applied to establish a predictive model for ...
|
| |
Building and Environment (04 January 2010)
Abstract
Thermal comfort research in India is in its nascent stage. Indian codes specify uniform comfort temperatures between 23 - 26 °C for all types of buildings. About 73% of energy in Indian residences is consumed for ventilation and lighting controls. Therefore, thermal comfort field survey was conducted in apartment buildings in Hyderabad, which included information on the use of building controls. The present analysis is based on this database. Due to the poor availability of adaptive opportunities, 60% of the occupants were uncomfortable in ...
|
| |
Building and Environment (28 December 2009)
Abstract
Mass-produced in a short period of time, Korea's public apartments contributed to easing the housing anxiety of the common people. Nonetheless, they also gave rise to problems of social exclusion and conflict, becoming undesirable facilities that weakened social health. This study examined ways of producing an improved building plan that can raise the level of social health of public apartments, which were consistently built in the past but will no doubt continue to be developed in the future. For this study, ...
|
| |
Building and Environment (22 December 2009)
Abstract
Due to a lack of accurate description of the coupled heat and formaldehyde migration in dry porous building materials, the characteristics of the heat and mass transfer has not been fully revealed. An improved model of coupled heat and formaldehyde migration is developed and analyzed to investigate the transport features in dry porous building materials. Based on the theory of non-equilibrium thermodynamics and molecular kinetics, the mechanisms of the heat and formaldehyde migration process in dry porous building materials are discussed. ...
|
| |
Building and Environment (21 December 2009)
Abstract
We regarded high-rise cities as obstacles and channels to wind. We first studied wind conditions and ventilations in idealized high-rise long street models experimentally and numerically with a constant street width ( W = 30 mm), variable street heights ( H = 2 W , 2.5 W , 3 W , 4 W ), variable street lengths ( L = 47.4 W , 79 W , 333 W , 667 W ) and a parallel approaching wind. The flow rates penetrating into windward entries are ...
|
Search
Search
