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  Subjects -> ENGINEERING (Total: 2298 journals)
    - CHEMICAL ENGINEERING (192 journals)
    - CIVIL ENGINEERING (192 journals)
    - ELECTRICAL ENGINEERING (104 journals)
    - ENGINEERING (1209 journals)
    - ENGINEERING MECHANICS AND MATERIALS (385 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (69 journals)
    - MECHANICAL ENGINEERING (92 journals)

CIVIL ENGINEERING (192 journals)                     

Showing 1 - 192 of 192 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 17)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 2)
Advances in Civil Engineering     Open Access   (Followers: 36)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 28)
Agregat     Open Access  
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 31)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 1)
Archives of Civil Engineering     Open Access   (Followers: 10)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 4)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 6)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 10)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 4)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 4)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 16)
Building & Management     Open Access  
Building and Environment     Hybrid Journal   (Followers: 15)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 15)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 6)
Canadian Journal of Civil Engineering     Hybrid Journal   (Followers: 12)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 9)
Cement and Concrete Composites     Hybrid Journal   (Followers: 17)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 2)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 5)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 7)
Civil And Environmental Engineering Reports     Open Access   (Followers: 6)
Civil and Environmental Research     Open Access   (Followers: 19)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 18)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 10)
Civil Engineering Dimension     Open Access   (Followers: 8)
Civil Engineering Infrastructures Journal     Open Access  
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 268)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 36)
Concrete Research Letters     Open Access   (Followers: 6)
Construction Economics and Building     Open Access   (Followers: 2)
Construction Engineering     Open Access   (Followers: 9)
Construction Management and Economics     Hybrid Journal   (Followers: 22)
Construction Science     Open Access   (Followers: 4)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 2)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 17)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 14)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 9)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 16)
Frattura ed Integrità Strutturale : Fracture and Structural Integrity     Open Access  
Frontiers in Built Environment     Open Access  
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Geomaterials     Open Access   (Followers: 4)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotechnik     Hybrid Journal   (Followers: 3)
Géotechnique Letters     Hybrid Journal   (Followers: 7)
GISAP : Technical Sciences, Construction and Architecture     Open Access  
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indonesian Journal of Urban and Environmental Technology     Open Access  
Indoor and Built Environment     Hybrid Journal   (Followers: 2)
Infrastructure Asset Management     Hybrid Journal   (Followers: 2)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 22)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 3)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 16)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 1)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 14)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 9)
International Journal of Geo-Engineering     Open Access   (Followers: 3)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 4)
International Journal of Masonry Research and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Pavement Research and Technology     Open Access   (Followers: 6)
International Journal of Protective Structures     Hybrid Journal   (Followers: 6)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 10)
International Journal of Structural Integrity     Hybrid Journal   (Followers: 2)
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Built Environment     Open Access   (Followers: 4)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 7)
International Journal Sustainable Construction & Design     Open Access  
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 15)
Journal of Building Engineering     Hybrid Journal   (Followers: 1)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 12)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 8)
Journal of Civil Engineering Research     Open Access   (Followers: 6)
Journal of Civil Engineering, Science and Technology     Open Access  
Journal of Civil Society     Hybrid Journal   (Followers: 4)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 24)
Journal of Construction Engineering     Open Access   (Followers: 7)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 19)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 8)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 4)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 6)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 2)
Journal of Green Building     Full-text available via subscription   (Followers: 11)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 14)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 21)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 5)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials and Engineering Structures     Open Access   (Followers: 5)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 11)
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 4)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 7)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 3)
Journal of Solid Waste Technology and Management     Full-text available via subscription   (Followers: 1)
Journal of Structural Engineering     Full-text available via subscription   (Followers: 40)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 3)
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 1)
Journal of the Civil Engineering Forum     Open Access  
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
Journal of Water and Environmental Nanotechnology     Open Access  
Jurnal Spektran     Open Access   (Followers: 1)
Jurnal Teknik Sipil dan Perencanaan     Open Access   (Followers: 1)
Konstruksia     Open Access  
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 2)
Latin American Journal of Solids and Structures     Open Access   (Followers: 4)
Materiales de Construcción     Open Access  
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 17)
npj Materials Degradation     Open Access  
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 7)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 2)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 4)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 12)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 4)
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 7)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 11)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 6)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 61)
Selected Scientific Papers - Journal of Civil Engineering     Open Access   (Followers: 3)
Slovak Journal of Civil Engineering     Open Access   (Followers: 2)
Soils and foundations     Full-text available via subscription   (Followers: 5)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 10)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 9)
Structural Engineering International     Full-text available via subscription   (Followers: 12)
Structural Mechanics of Engineering Constructions and Buildings     Open Access  
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 23)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 13)
Structures     Hybrid Journal   (Followers: 1)
Study of Civil Engineering and Architecture     Open Access   (Followers: 9)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access  
Teknik     Open Access  
The IES Journal Part A: Civil & Structural Engineering     Hybrid Journal   (Followers: 6)
The Structural Design of Tall and Special Buildings     Hybrid Journal   (Followers: 6)
Thin Films and Nanostructures     Full-text available via subscription   (Followers: 2)
Thin-Walled Structures     Hybrid Journal   (Followers: 4)
Transactions of the VŠB - Technical University of Ostrava. Construction Series     Open Access   (Followers: 1)
Transportation Geotechnics     Full-text available via subscription   (Followers: 1)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 8)
Underground Space     Open Access  
Water Science & Technology     Partially Free   (Followers: 25)
Water Science and Technology : Water Supply     Partially Free   (Followers: 22)

           

Journal Cover Building and Environment
  [SJR: 2.121]   [H-I: 86]   [15 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0360-1323
   Published by Elsevier Homepage  [3118 journals]
  • Air ventilation assessment under unstable atmospheric stratification — A
           comparative study for Hong Kong
    • Abstract: Publication date: 15 February 2018
      Source:Building and Environment, Volume 130
      Author(s): Weiwen Wang, Edward Ng
      In most current air ventilation assessment (AVA) studies, a simple neutral assumption that does not consider thermal effects is adopted, particularly for numerical simulation practices. With statistics of daytime observations during summer in Hong Kong as an example, this study demonstrates that neutral atmospheric boundary conditions occur with a very low probability, which implies that current practices are indeed far away from reality. This study is devoted to addressing this knowledge gap by cross-comparisons of field measurements, wind tunnel tests, and large-eddy simulations (LES) under neutral and unstable conditions. It is found that LES-computed velocity ratios under unstable conditions are in line with field measurements, while results of simulations under neutral conditions are close to those of wind tunnel tests. Enhanced vertical mixing due to surface heating produces improved ventilation performance in the unstable case. The neutral assumption tends to underestimate pedestrian-level velocity ratios compared to a diabatic condition; hence it is deemed conservative when it is adopted in AVA practices. Moreover, stronger wind direction variance under unstable conditions results in weaker correlation between velocity ratios and frontal area indices than neutral conditions, which implies that street orientations become less important in ventilation under unstable conditions.

      PubDate: 2017-12-27T05:46:37Z
       
  • Effects of the tree distribution and species on outdoor environment
           conditions in a hot summer and cold winter zone: A case study in Wuhan
           residential quarters
    • Abstract: Publication date: 15 February 2018
      Source:Building and Environment, Volume 130
      Author(s): Li Zhang, Qingming Zhan, Yuliang Lan
      Residential district is the important space for people living and outdoor activities. Vegetation is proved to be effectively regulate microclimate. Living in Wuhan, residents have to suffer heat stress in summer and strong cold wind in winter simultaneously. It is necessary to dictate vegetation types and layout in residential area to get comfortable environment both in hot summer and cold winter. This study examined the vegetation influences of residential wind environment in hot and cold seasons by using the ENVI-met model V4. Field measurement validated the performance of ENVI-met model. The simulation was based on multi-story buildings representing the current primary form of residential area in Wuhan. 3 scenarios with three tree arrangements and 8 vegetation species were simulated. Height-to-distance ratio of trees (as “Aspect ratio of trees”, ART) was used to describe the tree distribution. Results showed that the impact of vegetation on both heat environment and ventilation depended on tree arrangement, LAI, crown width and tree height. The comparison of 3 tree distributions revealed that trees with an ART < 2 should be a priority to mitigate hot environments due to the large effects on PET reduction in summer. Evergreen species with an ART < 2 also effectively decreased wind speed in winter as well as blocked direct sunlight, resulting in negative effects on PET. Tall trees with a large LAI and canopy diameter should be a priority to improve the comfort of outdoor environments.

      PubDate: 2017-12-27T05:46:37Z
       
  • Ozone reaction with human surfaces: Influences of surface reaction
           probability and indoor air flow condition
    • Abstract: Publication date: 15 February 2018
      Source:Building and Environment, Volume 130
      Author(s): Donghyun Rim, Elliott T. Gall, Sagar Ananth, Youngbo Won
      It is well-established that indoor surfaces, such as building materials, act as a sink for indoor ozone. However, comparatively little research has been done regarding ozone reactions with human surfaces such as skin and clothing. Reaction characteristics of human surfaces and airflow around the human body may affect ozone removal and reaction byproduct formation. The objective of this study is to investigate effects of the reactivity of human surfaces, modeled for a range of reaction probabilities (γ), on ozone deposition and reaction byproduct formation. Computational fluid dynamics models are verified and validated with previously published studies, and used to analyze ozone reaction dynamics due to human surfaces under varying indoor air flow conditions. The results show that for indoor environments with air exchange rate <5 h−1, ozone deposition velocity is in the range of 8–10 m/h for human skin oil while it is 2–3 m/h for clean clothing. Surface reactivity of the human body has a larger influence on the ozone deposition velocity than do the air exchange rates or indoor airflow patterns. Modeled emission rates of major reaction byproducts from ozone chemistry with human surfaces included acetone (0.3 mg/h/person), decanal (0.2 mg/h/person), nonanal (0.1 mg/h/person) and 6-MHO (0.1 mg/h/person) for a transport-limited scenario with 90 ppb bulk ozone concentration. These results imply that exposures to indoor ozone and reaction byproducts can be meaningfully modulated by an interaction of building airflow and chemistry occurring on and around individuals, and should be considered in models of human exposure.

      PubDate: 2017-12-27T05:46:37Z
       
  • Comparing the cooling effects of a tree and a concrete shelter using PET
           and UTCI
    • Abstract: Publication date: 15 February 2018
      Source:Building and Environment, Volume 130
      Author(s): Pui Kwan Cheung, C.Y. Jim
      Trees could provide notable cooling by intercepting solar radiation and evapotranspiration. Human-made shelters in urban areas also serve as shading devices. However, few studies have compared the cooling efficacy of trees and artificial shelters. This study systematically quantified and compared the daytime and nighttime cooling effects of a large Chinese Banyan tree (Ficus microcarpa) with dense foliage and an extensive concrete shelter, in an urban park in Hong Kong's subtropical summer. Microclimatic parameters at the two sites were monitored to compare air temperature, and the computed values of PET (Physiological Equivalent Temperature) and UTCI (Universal Thermal Climate Index). The mean daytime cooling effects generated by the tree were 0.6 °C (air temperature), 3.9 °C (PET) and 2.5 °C (UTCI), which were higher than the shelter at 0.2 °C, 3.8 °C and 2.0 °C respectively. The differences were significant for air temperature and UTCI (p < .001 and p < .05 respectively, t-test) but not for PET (p = .261). The tree's mean daytime maximum cooling effects were 2.1 °C (air temperature), 18.8 °C (PET) and 10.3 °C (UTCI). The tree's mean nighttime cooling was significantly higher than the shelter for all three indices (p < .001, t-test). The thermal stress classifications by PET and UTCI were significantly different on the neutral or warmer side (p < .001, Chi-squared test), suggesting that they cannot be used interchangeably. The findings could inform decisions on natural versus artificial shelters in urban thermal design, and trigger comparative investigations in using PET and UTCI for outdoor thermal comfort assessment.

      PubDate: 2017-12-27T05:46:37Z
       
  • Investigation on characteristics of thousand-meter height wind profiles at
           non-tropical cyclone prone areas based on field measurement
    • Abstract: Publication date: 15 February 2018
      Source:Building and Environment, Volume 130
      Author(s): Zhao Liu, Chaorong Zheng, Yue Wu, Yu Song
      Accurate representation of the atmospheric wind profiles is very important for the relevant research works on the environmental wind engineering and wind-resistance design of buildings. Recently, the characteristics of thousand-meter height wind field in the atmospheric boundary layer (ABL) are investigated based on the field measurement by a wind profiler, which was installed in a coastal area of China (121.75°E, 39.05°N). Specifically, mean wind velocity profiles and wind direction profiles measured during 16 strong windy days (synoptic wind) are analyzed in the present paper. It is found that based on the agglomerative clustering analysis, the mean wind velocity profiles can be divided into two categories, namely, I and R categories. For I category, the wind velocity increases with height monotonously. While for R category, the wind velocity reaches a maximum value at a height of 500–600 m, and then recedes with height. In most cases, I category wind velocity profile can envelope that of R category, and thus becomes the main consideration for the wind−resistance design of megatall buildings. Furthermore, for I category, the log−law can be used to describe the variation of wind velocities below the height of 360 m, while the power−law is valid up to 1000 m. With the increment of total twist angle and wind velocity, the variation of measured wind directions shows a better agreement with that implied by Ekman spiral. And the total wind twist angles can reach 5°–40° over the first 1000 m.
      Graphical abstract image

      PubDate: 2017-12-27T05:46:37Z
       
  • Multiple perspectives of the value of occupancy-based HVAC control systems
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Leila Nikdel, Kerop Janoyan, Stephen D. Bird, Susan E. Powers
      Occupancy-based strategies for reducing energy used for heating, ventilating, and air conditioning (HVAC) benefit building owners and help meet state and federal energy and climate goals. However, this value has not previously been quantified beyond typical building owner energy savings. The objective of this research is to estimate the national-level potential added-value of occupancy-based HVAC controls in small office buildings relative to a constant setpoint or to programmable thermostats. Value is defined based on the building owner perspective (energy cost), as well as societal based perspectives of fossil fuels consumed and greenhouse gas, NOx and SOx emissions. A generic small office building with two different HVAC systems is simulated in EnergyPlus and applied to five climate zones representative of the United States. Specific building envelope, electricity supplies, utility costs and total area of small office buildings are adjusted for each climate zone. Results demonstrate that occupancy-based strategies for HVAC control are highly effective, yielding 22-50%and 47-87% reduction in electricity and natural gas use, respectively, compared to no thermostat control. Results vary substantially across climate zones and HVAC systems. With occupancy sensors installed in all small office buildings, the U.S. national savings would be 15 - 66 million GJ fossil fuel use, 0.9–3.7 million metric tons CO2e emissions, and 168 - 658 million dollars for utility cost.

      PubDate: 2017-12-27T05:46:37Z
       
  • Human-building interaction under various indoor temperatures through
           neural-signal electroencephalogram (EEG) methods
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Xin Shan, En-Hua Yang, Jin Zhou, Victor W.-C. Chang
      In this study, potential of neural-signal electroencephalogram (EEG)-based methods for enhancing human-building interaction under various indoor temperatures were explored. Correlations between EEG and subjective perceptions/tasks performance were experimentally investigated. Machine learning-based EEG pattern recognition was further studied. Results showed that the EEG frontal asymmetrical activity related well to the subjective questionnaire and objective tasks performance, which can be used as a more objective metric to corroborate traditional subjective questionnaire-based methods and task-based methods. Machine learning-based EEG pattern recognition with linear discriminant analysis (LDA) classifiers can well classify the different mental states under different thermal conditions. Utilization of the EEG frontal asymmetrical activities and the machine learning-based EEG pattern recognition method as a feedback mechanism of occupants, which can be implemented on a routine basis, has a great potential to enhance the human-building interaction in a more objective and holistic way.
      Graphical abstract image

      PubDate: 2017-12-27T05:46:37Z
       
  • Parametric study of air curtain door aerodynamics performance based on
           experiments and numerical simulations
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Dahai Qi, Sherif Goubran, Liangzhu (Leon) Wang, Radu Zmeureanu
      Air curtains have been widely used to reduce infiltration through door openings and save heating/cooling energy in different types of buildings. Previous studies have found that there exist three aerodynamics conditions: optimum condition (OC), inflow break-through (IB), and outflow break-through (OB) conditions, which are important for categorizing air curtain performance subject to such key parameters including supply speed and angle, and presence of a person during an actual operation. However, few studies have focused on the effects of these parameters on air curtain performance in terms of resisting infiltration and reducing exfiltration. This research presents a parametric study of air curtain performance based on reduced-scale experiments and full-scale numerical simulations. It was found that increasing air curtain supply angle improves air curtain performance when it is operated under the OC and IB conditions but creates excessive exfiltration under the OB condition. Increasing supply speed of air curtain generally improves the air curtain performance whereas this improvement deteriorates with the increase of supply angle under the OB condition. The presence of person, either directly under or below the air curtain, almost has no effect on the infiltration/exfiltration during the OC condition. Moreover, the person in the doorway can block airflow from both directions, contributing to less infiltration under the IB condition and less exfiltration under the OB condition than without the person. This study provides valuable insights into air curtain aerodynamics performance under different operational conditions and key contributing parameters.

      PubDate: 2017-12-27T05:46:37Z
       
  • Influence of air change rates on indoor CO2 stratification in terms of
           Richardson number and vorticity
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Hua-Yan Deng, Zhuangbo Feng, Shi-Jie Cao
      Above rules-of-thumb ventilation standard based on air change rate per hour (ACH), it is necessary to assess the indoor airflow and indoor air quality (IAQ) with respect to simple dimensionless numbers from the practical point of view. Hence, this work aims at investigating the influence of air change rates on indoor CO2 stratification and removal with dimensionless time scale ratio (proportional to Ri/α, Richardson number Ri, mass flux ratio α) and vorticity by applying experiment and simulation methods. We firstly carried out a series of experiments with different ACHs along with constant CO2 pollutant sources, further for simulation validation. Next, numerical simulation was employed to investigate five different ACHs (ranged from 4 to 28) on indoor CO2 concentration for two different vent-inlet-size cases. It was found that as the increase of ACH, the averaging outlet CO2 concentration was decreased until ACH equal to 16, both cases starting showing asymptotic behavior. When looking at indoor CO2 distribution, the case with larger vent-inlet size showed clear stratification even with higher ACH value (i.e., 28), due to the relatively smaller vorticity value (i.e., 0.47, with 3.14 for small-vent-size case) and larger Ri magnitude (37 times) compared to the small-vent-size case. Specifically, it is beneficial for indoor CO2 removal to keep time scale ratio Ri/α below 10−3 and vorticity above 1 rather than merely following with high ACH values. These findings will be of great importance for practical applications to design and control ventilation systems in the perspective of health and energy efficiency.
      Graphical abstract image

      PubDate: 2017-12-27T05:46:37Z
       
  • Personal comfort models: Predicting individuals' thermal preference using
           occupant heating and cooling behavior and machine learning
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Joyce Kim, Yuxun Zhou, Stefano Schiavon, Paul Raftery, Gail Brager
      A personal comfort model is a new approach to thermal comfort modeling that predicts individuals' thermal comfort responses, instead of the average response of a large population. However, securing consistent occupant feedback for model development is challenging as the current methods of data collection rely on individuals' survey participation. We explored the use of a new type of feedback, occupants' heating and cooling behavior with a personal comfort system (PCS) for the development of personal comfort models to predict individuals' thermal preference. The model development draws from field data including PCS control behavior, environmental conditions and mechanical system settings collected from 38 occupants in an office building, and employs six machine learning algorithms. The results showed that (1) personal comfort models based on all field data produced the median accuracy of 0.73 among all subjects and improved predictive accuracy compared to conventional models (PMV, adaptive) which produced a median accuracy of 0.51; (2) the PMV and adaptive models produced individual comfort predictions only slightly better than random guessing under the relatively mild indoor environment observed in the field study; and (3) the models based on PCS control behavior produced the best prediction accuracy when individually assessing all categories of field data acquired in the study. We conclude that personal comfort models based on occupants' heating and cooling behavior can effectively predict individuals' thermal preference and can therefore be used in everyday comfort management to improve occupant satisfaction and energy use in buildings.
      Graphical abstract image

      PubDate: 2017-12-27T05:46:37Z
       
  • Characterizing dynamic transmission of contaminants on a surface touch
           network
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Shenglan Xiao, Yuguo Li, Hao Lei, Chao-Hsin Lin, Sharon L. Norris, Xinyan Yang, Pengcheng Zhao
      Our understanding of the fomite transmission route of diseases remains at an empirical level. There are no data on how surface contamination is propagated by human touching. We designed a novel and effective benchtop experiment to investigate the dynamic transmission of contaminants on multiple environmental surfaces due to touching. The benchtop experiment setting design was based on an inflight norovirus outbreak. Hundreds of representative environmental surfaces in the plane were scaled down, and fluorescent particles were used as surrogate indicators of virus-laden aerosols. The fluorescent particles were initially carried by six index “patients” and then transmitted to other surfaces through the touching behavior of one hundred and twenty-four “passengers.” The distributions of fluorescent particles were photographed by cameras when exposed to UV light and the acquired photos were processed using fluorescence imaging techniques to quantify fluorescent particles on each surface. The temporal diffusion of contaminated surfaces was found to follow an S-shaped logistic curve. The aisle seats were found to be more contaminated, which was consistent with the reported higher attack rates in passengers seating along the aisle in the outbreak. This study confirmed the findings of the logistic growth from the multi-agent simulations, and provided a possible mechanism for the role played by environmental surfaces in the fomite route of diseases.

      PubDate: 2017-12-27T05:46:37Z
       
  • Vertical ventilation concepts for future passenger cars
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Tobias Dehne, Pascal Lange, André Volkmann, Daniel Schmeling, Mikhail Konstantinov, Johannes Bosbach
      We compared three vertical ventilation concepts to dashboard ventilation in a generic car cabin with the aim to improve thermal passenger comfort and energy efficiency of future cars. Temperatures were analyzed with an infrared camera and local temperature sensors. Omnidirectional velocity probes were used to capture the fluid velocities and temperatures in the vicinity of thermal passenger dummies, which were used to simulate the thermal impact of the passengers. Further, the ventilation efficiency was measured with the tracer gas technique using humidity sensors in the vicinity of the dummies and in the air outlets. Besides the experimental investigations, the relevant flow cases were studied by Computational Fluid Dynamics simulations using the RANS method, providing insight into the complex and three-dimensional flow structures of the passenger compartment. Validation of the simulations with the experimental data revealed acceptable consistency, however, with local deviations indicating further need for experimental investigations. The ventilation efficiencies of the vertical ventilation concepts were at least comparable or even better as compared to dashboard ventilation. Regarding the comfort-relevant flow parameters, dashboard ventilation stood out with the lowest temperature stratification but revealed comfort-critical flow velocities. The vertical ventilation concepts allowed for comfortable velocities, but tended to produce comfort-critical temperature stratifications. Pursuing the equivalent temperatures, the vertical systems revealed an improved heating performance over dashboard ventilation. During summer and spring/fall conditions, low momentum ceiling ventilation as well as the combination of cabin displacement ventilation and low momentum ceiling ventilation were able to provide comfortable equivalent temperature distributions.

      PubDate: 2017-12-27T05:46:37Z
       
  • Letter from the Editor
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128


      PubDate: 2017-12-27T05:46:37Z
       
  • Prediction model of microclimatic surface conditions on building
           façades
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Stergiani Charisi, Thomas K. Thiis, Petter Stefansson, Ingunn Burud
      The microclimatic surface conditions of a building façade are critical for determining the degradation of the façade material. Most models use the ambient temperature and RH to predict mould growth and decay on building materials. On the other hand, Heat, Air and Moisture (HAM) simulation software able to calculate the surface conditions, treats the whole façade uniformly without including architectural characteristics of the façade, such as window sills or overhangs, which can have shadowing effect. A simulation model that takes into consideration both the local microclimate and the spatial architectural characteristics of the façade has been developed to predict the spatial surface temperature and moisture content over a whole façade. The model is validated through measurements for two different building façades – wooden consisting of aspen (Populus tremula) and masonry consisting of red fire clay bricks. The measurements include monitoring of the spatial surface temperatures with an infrared camera, and logging of the surface moisture content of selected points on the façade using wood resistance humidity sensors. The validation shows that the simulation model can predict the microclimatic surface conditions with high accuracy and can sufficiently capture the spatial variations of surface temperature and moisture content over a building façade.

      PubDate: 2017-12-27T05:46:37Z
       
  • Simultaneous identification of dynamic model and occupant-induced
           disturbance for commercial buildings
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Austin R. Coffman, Prabir Barooah
      A model of a building's thermal dynamics is needed for prediction-based control. The task of identifying a thermal dynamic model is made challenging by the presence of large unmeasured disturbances, especially the heat gain due to the occupants. In fact, identification of this “occupant-induced load” is also valuable for predictive control—especially in commercial buildings. We propose a method to identify both a model (of resistance-capacitance network type) and the unmeasured disturbances from measured input-output data. The method is based on the insight that the main contributor to the unmeasured disturbance, the occupant-induced load, is piecewise constant, especially in commercial buildings. This can be used to construct an augmented dynamic model so that disturbance estimation is converted to a state estimation problem. An outer-loop optimization identifies the best-fit parameter values. The effectiveness of the method is evaluated using data from a simulation model (under both open and closed-loop operations) and a real building.

      PubDate: 2017-12-27T05:46:37Z
       
  • Comparing electric heating systems at equal thermal comfort: An
           experimental investigation
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Jérémie Léger, Daniel R. Rousse, Kilian Le Borgne, Stéphane Lassue
      Electric heaters are still widely used for residential heating. It is often believed that electric systems all perform equally; however, this is not the case as diffusors distribute heat in different ways. In this study, an experimental investigation of electric heating systems shows that heat distribution can indeed influence the effectiveness of the equipment to maintain thermal comfort. A baseboard heater, a convector and a radiant heater are compared at equal thermal comfort conditions in a bi-climatic chamber at different cold room temperatures. To demonstrate the repeatability of the results, a statistical analysis is presented. Results show that the convector consumes less energy than the baseboard and radiant heaters despite achieving similar thermal comfort. Though only small differences were observed, the investigation shows that electric heating systems are not all equal in energy efficiency. There is thus an opportunity to improve the heating effectiveness by improving the heat distribution of the equipment.

      PubDate: 2017-12-27T05:46:37Z
       
  • Can a Clean-Air Heat Pump (CAHP) maintain air purification capability when
           using polluted air for regeneration'
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Ying Sheng, Lei Fang
      Clean Air Heat Pump (CAHP) was one type of rotary desiccant cooling system which combined a silica gel rotor with a heat pump to achieve air cleaning, dehumidifying and cooling in buildings. Using exhaust air from the conditioned room for regeneration of the silica gel rotor might have an advantage on reducing the regeneration air temperature and further improving the energy performance of the CAHP. However, the exhaust air carried a lot of indoor air pollutants. Whether using exhaust air for the regeneration of the silica gel rotor had an impact on the air cleaning performance of the CAHP was experimentally studied. The results showed that using the air contained acetone or toluene for regeneration reduced the pollutants removal capability of CAHP with a reduction of approx. 10% in air cleaning efficiency. The energy performance of the CAHP when using exhaust air for regeneration was also evaluated compared with the CAHP with outdoor air for regeneration by means of numerical simulation. The simulated results showed that the energy saving of the CAHP was obvious when using exhaust air for regeneration, regardless of the degradation of indoor air quality. If the same indoor air quality level as that when using outdoor air for regeneration was expected to be maintained, increasing the intake of outdoor air was one possible way but would increase the energy consumption. The increased energy counteracted the reduced energy of using exhaust air for regeneration, and consequently the energy of CAHP was not saved.

      PubDate: 2017-12-27T05:46:37Z
       
  • Numerical investigation of SVOC mass transport in a tube by an
           axisymmetric lattice Boltzmann method
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Yun-Feng Mao, Zhuo Li, Yu-Tong Mu, Ya-Ling He, Wen-Quan Tao
      This paper presents an adsorption boundary condition based on linear adsorption isotherm for Lattice Boltzmann (LB) model. An axisymmetric 2-D LB model is built for an axisymmetric device. The model is used to study the effects of surface adsorption and airflow on SVOC mass transport in the device. In terms of surface adsorption, the research is divided in two parts: pure diffusion and convection-diffusion. The results show that the simulated data based on the presented adsorption boundary agree well with experimental data. In both the pure diffusion and advection-diffusion process, surface adsorption has no impact on the steady-state concentration, but it affects the time to reach steady state. Airflow greatly reduces both the time to reach steady state and the steady-state concentration. An exponential relationship involving h m , ACH and velocity is proposed and verified experimentally. Discussion on the parameter n in the exponential relation is conducted.

      PubDate: 2017-12-27T05:46:37Z
       
  • A bioclimatic approach to develop spatial zoning maps for comfort, passive
           heating and cooling strategies within a composite zone of India
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Khambadkone Naveen Kishore, Jain Rekha
      Bioclimatic potential studies are important for passive design applications in the conceptual stage of climate responsive building design. Being a land of vast climatic diversity, very few such studies exist in India. This paper aims to develop bio climatic charts for 21 locations within a composite climate zone in India. Spatial zoning maps for natural comfort and passive heating and cooling strategies have been developed for these 21 selected locations based on adaptive comfort criteria. A further evaluation of the bioclimatic potential analysis was carried out through a simple heating and cooling energy load simulation for all locations. Impact of the local climate on building heating and cooling energy load was evaluated using statistical techniques thus establishing a direct relationship between bioclimatic potential and annual energy load. Results show great variation in comfort and passive design potential even within the composite zone. A gradual increase in the number of comfort hours was observed as one moves geographically from the north towards south within the composite zone. The natural comfort potential varies from 23 to 46%, passive cooling potential varies between 26.5 and 53.5% and the passive solar heating potential varies from 3 to 20% of the time of the year based on location. Results of this study can be used for further sub-zoning of the composite region based on thermal comfort and passive design criteria, which will further the development of location specific passive design strategies. Limitations of the present study and scope for future investigation are also delineated.

      PubDate: 2017-12-27T05:46:37Z
       
  • Identifying critical building morphological design factors of street-level
           air pollution dispersion in high-density built environment using mobile
           monitoring
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Yuan Shi, Xiaolin Xie, Jimmy Chi-Hung Fung, Edward Ng
      In high-density cities, optimization of their compact urban forms is important for the enhancement of pollution dispersion, improvement of the air quality, and healthy urban living. This study aims to identify critical building morphological design factors and provide a scientific basis for urban planning optimization. Through a long-term mobile monitoring campaign, a four-month (spanning across summer and winter seasons) spatiotemporal street-level PM2.5 dataset was acquired. On top of that, the small-scale spatial variability of PM2.5 in the high-density downtown area of Hong Kong was mapped. Seventeen building morphological factors were also calculated for the monitoring area using geographical information system (GIS). Multivariate statistical analysis was then conducted to correlate the PM2.5 data and morphological data. The results indicate that the building morphology of the high-density environment of Hong Kong explains up to 37% of the spatial variability in the mobile monitored PM2.5. The building morphological factors with the highest correlation to PM2.5 concentration are building volume density, building coverage ratio, podium layer frontal area index and building height variability. The quantitative correlation between PM2.5 and morphological factors can be adopted to develop scientifically robust and straightforward optimization strategies for planners. This will allow considerations of pollution dispersion to be incorporated in planning practices at an early stage.

      PubDate: 2017-12-27T05:46:37Z
       
  • Making sense of building data: New analysis methods for understanding
           indoor climate
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Angela Geronazzo, Gail Brager, Sanyogita Manu
      This work presents a novel approach for exploratory analysis of indoor environment measurements. Building monitoring is a complex task constrained by technological and environmental limits. Monitoring processes can be long, employ multiple sensors and equipment, and may involve multiple buildings across extended periods. Once the data is collected, it's not always straightforward how to make sense of it. When faced with complex heterogeneous amounts of data, early exploratory analysis is helpful to make sense of the broad patterns, highlight data weaknesses and features, and identify directions for more in-depth analysis. Inaccuracy, incompleteness and inconsistence are common characteristics of monitored field data, which then often needs intensive pre-processing to address data quality issues and improve data analysis results. This paper describes techniques from computer science, such as decision tree induction and others, that are not normally applied to field measurements of indoor environments in buildings, and as an example applies them to a complex set of data from climate-responsive spaces in India. The findings illustrate the power of these techniques for using simplified measures as proxies to extract more sophisticated information about building operation, and for quickly identifying patterns in how different design and operational characteristics affect thermal comfort.

      PubDate: 2017-12-27T05:46:37Z
       
  • A tool for assessing life cycle CO2 emissions of buildings in Sri Lanka
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Ramya Kumanayake, Hanbin Luo
      The critical role of buildings in overcoming global environmental challenges is evident from their high contribution to global energy use and carbon dioxide (CO2) emission. This study was aimed at developing a life cycle CO2 emission estimator tool for buildings in Sri Lanka. First, system requirements and system boundary were identified. Then CO2 emission calculation method for each life cycle stage was established, which was followed by development of building life cycle CO2 emission database and program. The applicability of developed tool was evaluated by a case study of a multi-storey building in Sri Lanka. In the case study, operation and maintenance stage contributed to 55.47% of life cycle CO2 emission, which was followed by material production stage (42.09%). Ready-mixed concrete, reinforcement steel, cement and clay bricks contributed to nearly 90% of CO2 emission at material production stage. To the best of our knowledge, this study is the first-ever attempt at developing a building life cycle CO2 emission estimator tool for Sri Lanka. The limited availability of local data for some life cycle stages was the main challenge faced by researchers, as national data inventories for building life cycle CO2 emissions are still not fully developed in Sri Lanka. The tool can be used to compare life cycle CO2 emissions of different buildings as well as providing means of assessing compliance of life cycle CO2 emissions of buildings to CO2 emission standards specified by green building certification bodies in Sri Lanka, thus promoting sustainable construction practices in the country.

      PubDate: 2017-12-27T05:46:37Z
       
  • On the performance of LCC optimization software OPERA-MILP by comparison
           with building energy simulation software IDA ICE
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Vlatko Milić, Klas Ekelöw, Bahram Moshfegh
      From an economic point of view, it is crucial to minimize the life cycle costs (LCC) of buildings undergoing energy renovations, hence an optimization approach is needed. Building energy use and power demand as well as energy efficiency measures are important issues while performing an LCC optimization. Thus it is of great importance to accurately predict the building energy use and power demand before and after energy renovation. This paper aims to address the performance of an in-house LCC optimization software, OPERA-MILP, which has a rather fast optimization procedure. The aim is fulfilled through comparison with building energy simulation software IDA ICE before and after cost-optimal energy renovation. Three historic buildings with different layout and construction properties are used as a case study. The results show good agreement in the calculations of buildings' power demand and energy use between OPERA-MILP and IDA ICE. The percentage difference in calculated annual energy use and buildings' power demand with OPERA-MILP compared to IDA ICE is shown to be maximum 11% and 8% for the studied climate zones, respectively. Total impact on LCC is estimated to be equal to or less than 8%.

      PubDate: 2017-12-27T05:46:37Z
       
  • Interplay of ventilation and filtration: Differential analysis of cost
           function combining energy use and indoor exposure to PM2.5 and ozone
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Tom Ben-David, Michael S. Waring
      This study investigated the effects of ventilation and filtration on building energy consumption and exposure to PM2.5 and ozone in U.S. offices. Energy use and indoor PM2.5 and ozone concentrations were predicted in 15 locations for a typical office with either a constant air volume (CAV) or variable air volume (VAV) mechanical system. For each office and location, annual simulations were performed with combinations of fixed ventilation ranging 20–100 CFM/occ (9.4–47 L/s/occ) and filters ranging in efficiency corresponding to MERV 8–16 and HEPA. Energy use was monetized using historic costs, and PM2.5 and ozone exposures were monetized using incidence valuations and concentration-response functions. These outcomes were combined into a singular cost function, which was characterized empirically as a function of ventilation and filtration. Various partial derivatives of the cost function were calculated to observe trends and interdependencies. Exposure cost was 5.5 times higher than energy cost for cases with common filters (MERV 8–11). Even with high filter efficiency, exposure cost was greater than energy cost on average. Filtration had a much stronger effect than ventilation on indoor contaminant levels and the total cost function. The differential analysis revealed that ventilation and filtration complement each other: Implementing a high efficiency filter can mitigate negative effects of ventilation, and higher ventilation rates can increase the efficacy of filtration (e.g. increasing ventilation from 20 to 60 CFM/occ increased filtration efficacy by 1.2–1.5 for VAV offices).

      PubDate: 2017-12-27T05:46:37Z
       
  • Thermal comfort in interior and semi-open spaces of rural folk houses in
           hot-humid areas
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Zhongjun Zhang, Yufeng Zhang, Ling Jin
      Semi-open spaces are a key element in the climate adaptive design of rural folk houses and are important places where rural residents perform daily activities in hot-humid areas. In this study, a year-long thermal comfort field survey was conducted in rural folk houses in 11 rural areas in the Guangdong Province, the hot-humid area of southern China. The subjective responses of residents were recorded via questionnaires, and all ambient environment parameters were measured. The results show that air speed was greater and relative humidity was lower in the semi-open spaces. The clothing insulation of the survey respondents varied with indoor operative temperatures from 0.27 clo to 1.2 clo during the non-summer season and remained steady at 0.30 clo during the summer season. The thermal neutral, acceptable and preferred indoor operative temperatures were determined for the interior and semi-open spaces in the summer and non-summer. Compared to those of the interior spaces, the thermal neutral temperature was 0.6–1.3 °C lower and the upper limit of 80% acceptable temperature was decreased by 0.8–4.7 °C in the semi-open spaces. The acceptable temperature in the summer for the rural residents was found to be 0.2–1 °C higher than that of the urban residents in the same climate. Psychological factors such as local culture, expectations and perceived control might be the reasons for these differences. This study contributes to a better understanding of the thermal comfort of rural people and to the improvement of rural living conditions.

      PubDate: 2017-12-27T05:46:37Z
       
  • Interior insulation – Experimental investigation of hygrothermal
           conditions and damage evaluation of solid masonry façades in a listed
           building
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Tommy Odgaard, Søren Peter Bjarløv, Carsten Rode
      Exterior walls in historic multi-storey buildings compared to walls in modern buildings have low thermal resistance, resulting in high energy loss and cold surfaces/floors in cold climates. When restrictions regarding alteration of the exterior appearance exist, interior insulation might be the only possibility to increase occupant comfort. This paper describes an investigation of the hygrothermal influence when applying 100 mm of diffusion open interior insulation to a historic multi-storey solid masonry spandrel. The dormitory room with the insulated spandrel had a normal indoor climate with a maximum observed monthly average humidity by volume excess of 3.2 g/m3 during the experiment. Relative humidity and temperature were monitored manually using wooden dowels over 2 years and 8 months in two solid masonry spandrels: one insulated wall and one untreated wall. The investigation showed that installing insulation on a solid masonry spandrel induced hygrothermal changes: Uniformly distributed higher relative humidity and lower temperature throughout the masonry, compared to an un-insulated wall. The relative humidity of the un-insulated masonry wall was in the range 50% on the inside to 60% on the outside, while the insulated wall showed uniformly distributed values around 80%. The risk of moisture-induced damage was evaluated based on mathematical models for mould and decay of wood, visual inspection for frost and mould, and on-site measurements for presence of mould spores. The damage evaluation showed no risk of damage from the changed hygrothermal conditions when applying interior insulation to a solid masonry spandrel.

      PubDate: 2017-12-13T08:49:20Z
       
  • Relationship between street scale and subjective assessment of
           audio-visual environment comfort based on 3D virtual reality and
           dual-channel acoustic tests
    • Abstract: Publication date: 1 February 2018
      Source:Building and Environment, Volume 129
      Author(s): Fangfang Liu, Jian Kang
      We examine the influence of street scales (the street width, building height, and street-width-to-building-height ratio, referred to as ‘width-to-height ratio’ in the paper) on visual, acoustic, and audio-visual comfort evaluation (as evaluated by a set of participants) in urban areas. In addition, we examine the relationships between the sound level and the abovementioned subjective comfort evaluation except the visual one. After measuring the street scales and recording the street visual information with a 3D camcorder, the virtual 3D models of the streets were generated. Meanwhile, dual-channel acoustic signals of the streets were collected. Subsequently, subjective tests were carried out using a 3D virtual reality with corresponding sounds using 164 participants. The analysis shows that subjective attitudes are directly related to the street scales. In particular, there is a strong positive correlation between audio-visual comfort and the street width-to-height ratio. In contrast, the three indicators (visual, acoustic, and audio-visual comfort) are strongly negatively correlated to the height, and this type of negative correlation is also observed between subjective indicators (except the visual one) and the sound level. Overall, the respondents found the audio-visual level most comfortable when the street width-to-height ratio is greater than 1, street width is within 20 m, height of street buildings is less than 26 m, and the sound level is less than 58 dBA. It is expected that these findings can aid designers in predicting the ideal audio-visual environment quality for urban streets.
      Graphical abstract image

      PubDate: 2017-12-13T08:49:20Z
       
  • A study of hybrid ventilation in an institutional building for predictive
           control
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Sophie Yuan, Charalampos Vallianos, Andreas Athienitis, Jiwu Rao
      Hybrid ventilation can be employed to precool thermally massive buildings, reducing energy consumption for cooling the following day, particularly at night when the outdoor temperature is lower, and especially when its operation is done in a predictive manner by incorporating weather forecasts. An important requirement is defining the temperature low limit for admitting exterior cool air into a building through transition spaces, to ensure thermal comfort. This paper uses a case study of a 17-story high institutional building with a hybrid ventilation system. To develop a strategy for the admission of outside air into the building, this study focuses on the corridors as generic transition zones/buffer spaces with flexible thermal comfort limits and with the motorized façade openings to determine how the air temperature evolves with distance from the inlets. A developed thermal model, calibrated from a full-scale test, calculates the amount of heat removed from the 0.4 m thick concrete floor. Through 4 h of night cooling with an average local exterior temperature of 8.3 °C, the air temperature rises to about 12 °C in the transition corridor region at a time when occupancy in that area is expected to be nearly zero. Taking into consideration the flexibility in thermal comfort in the corridor transition spaces, control strategies are developed, based on exterior temperature and humidity. Using humidity ratio instead of relative humidity as criterion for admitting outdoor air potentially results in the system being active for 49% - 180% more hours during the year.

      PubDate: 2017-12-13T08:49:20Z
       
  • Estimation and optimisation of buildings' thermal load using LiDAR data
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Marko Bizjak, Borut Žalik, Gorazd Štumberger, Niko Lukač
      With the growing urbanization and environmental concerns over buildings' energy consumption and carbon footprint, the demand for energy-efficient building design is greater than ever. This paper addresses these concerns by presenting a novel method for estimating and optimising the thermal load (i.e. total energy load for heating and cooling) of a building within a real environment, provided by high-resolution LiDAR data, while considering long-term climatological parameters, estimated direct and anisotropic diffuse irradiance, shadowing from surroundings, and terrain topography. In the optimisation part of the method, the building's design is optimised regarding the estimated thermal load. The estimation was validated with the well-established EnergyPlus software. In experiments, a rectangular building's design was optimised on a flat and urban dataset. The effect of a building's design parameters on thermal load was inspected as well. On average, the proposed method improved a building's net heat gain by over 103 kWh/m2 and reduced its thermal load by 234.18 kWh/m2 when compared with the initial building design.

      PubDate: 2017-12-13T08:49:20Z
       
  • Effectiveness of intermittent personalized ventilation in protecting
           occupant from indoor particles
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Douaa Al Assaad, Carine Habchi, Kamel Ghali, Nesreen Ghaddar
      In this study, the performance of an intermittent periodic personalized ventilation (PV) coupled with mixing ventilation (MV) was investigated with respect to its ability in protecting occupant from contaminants present in the space. To perform this study, a transient 3D computational fluid dynamics (CFD) model was used to assess the velocity, temperature and particle concentration fields in the space. Experiments were performed in a climatic chamber using a thermal manikin in order to validate the CFD model's predictions of the fluid flow and particle distribution in the space at supply MV flow rate of 63 L/s and room temperature of 28 °C and PV average flow rate of 3.5 L/s, supply temperature of 24 °C, and frequencies of 0.3 Hz and 1 Hz. Good agreement was found between the CFD model and experiments. The validated model was used to recommend PV operating parameters which would assure occupant protection from macroclimate contaminants' migration to the breathing zone and microclimate surrounding the occupant, and reduce particles' deposition on the surfaces in occupant proximity. It was found that an average flowrate of 7.5 L/s as well as an operating frequency of 0.86 Hz provided acceptable values of intake fractions in the breathing zone and the surrounding microclimate as well as acceptable values of deposition rates. These conditions provide good thermal comfort levels (0.87: comfortable), and good ventilation effectiveness (77.1%).
      Graphical abstract image

      PubDate: 2017-12-13T08:49:20Z
       
  • A probabilistic-based methodology for predicting mould growth in
           façade constructions
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Klodian Gradeci, Nathalie Labonnote, Berit Time, Jochen Köhler
      Predicting mould growth on façade constructions during design is important for preventing financial loss, and ensuring a healthy and comfortable indoor environment. Uncertainties in predicting mould growth are related to the representation of the biological phenomenon, the climate exposure and the material uncertainties. This paper proposes a probabilistic-based methodology that assesses the performance of façade constructions against mould growth and accounts for the aforementioned uncertainties. A comprehensive representation of mould growth is ensured by integrating several mould models in a combined outcome. This approach enables a more comprehensible and useful illustration between continuous mould growth intensities and their corresponding likelihoods. The outdoor climate exposure is represented by stochastic models derived by real time-series analysis according to autoregressive–moving-average models. The methodology is applied to investigate the influence of several parameters and the performance of several construction assemblies. This paper proposes a method to evaluate the façade performance that can facilitate reliability-based design and optimisation of façade construction.

      PubDate: 2017-12-13T08:49:20Z
       
  • An alternative algorithm of tunnel piston effect by replacing
           three-dimensional model with two-dimensional model
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Minzhang Liu, Chunguang Zhu, Tong Cui, Huan Zhang, Wandong Zheng, Shijun You
      With the rapid development of the underground railways in China, the subway has become an increasingly important mode of transportation. Owing to the significant influence piston wind has on tunnel ventilation, piston wind has gained much attention from researchers. At present, the most common method for this research is a three-dimensional Computational Fluid Dynamics (CFD) simulation. However, the three-dimensional model has its inherent characteristics. Large number of grid quantities, long calculation times, significant computational requirements and high technical personnel requirements all influence the development of the three-dimensional model applied into the practical engineering. This study aimed to simplify the complicated three-dimensional model by creating a simple two-dimensional dynamic mesh model while ensuring the accuracy of the simplified simulation results. In order to explore suitable alternative methods, six types of two-dimensional simulation models are suggested in this study. Firstly, in order to prove the accuracy of the dynamic mesh simulation method, the CFD simulation results were validated with experimental results. Secondly, the six alternative methods were applied to the experimental model, full-scale model, train passing through a tunnel model, and subway station model in order to determine the best two-dimensional method. Finally, grid number, calculation time, and internal storage usage between the two-dimensional simulations and the three-dimensional simulation were evaluated, and these results demonstrated the superiority of the two-dimensional simulation model.

      PubDate: 2017-12-13T08:49:20Z
       
  • Modelling of evaporation of cough droplets in inhomogeneous humidity
           fields using the multi-component Eulerian-Lagrangian approach
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Xiangdong Li, Yidan Shang, Yihuan Yan, Lin Yang, Jiyuan Tu
      This study employed a multi-component Eulerian-Lagrangian approach to model the evaporation and dispersion of cough droplets in quiescent air. The approach is featured with a continuity equation being explicitly solved for water vapor, which allows comprehensively considering the effects of inhomogeneous humidity field on droplets evaporation and movement. The computational fluid dynamics (CFD) computations based on the approach achieved a satisfactory agreement with the theoretical models reported in the literature. The results demonstrated that the evaporation-generated vapor and super-saturated wet air exhaled from the respiratory tracks forms a “vapor plume” in front of the respiratory track opening, which, despite the short life time, significantly impedes the evaporation of the droplets captured in it. The study also revealed that due to the droplet size reduction induced by evaporation, both the number density of airborne droplets and mass concentration of inhalable pathogens remarkably increased, which can result in a higher risk of infection. Parametric studies were finally conducted to evaluate the factors affecting droplet evaporation. Summary The study demonstrated the importance of considering inhomogeneous humidity field when modelling the evaporation and dispersion of cough droplets. The multi-component Eulerian-Lagrangian model presented in this study provides a comprehensive approach to address different influential factors in a wide parametric range, which will enhance the assessment of the health risks associated with droplet exposure.

      PubDate: 2017-12-13T08:49:20Z
       
  • Flow characteristics in occupied zone – An experimental study with
           symmetrically located thermal plumes and low-momentum diffuse ceiling air
           distribution
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Sami Lestinen, Simo Kilpeläinen, Risto Kosonen, Juha Jokisalo, Hannu Koskela, Arsen Melikov
      Airflow interaction between thermal plumes and vertical air distribution may cause significant effects on airflow characteristics such as velocity and temperature fields, turbulence intensity and fluctuation frequency. The flow interaction creates a random flow motion, vortical structures and turbulent mixing that can further yield a draught discomfort in an occupied zone. The main objective was to investigate large-scale airflow patterns and fluctuations as a result of interaction of buoyancy flows and diffuse ceiling flow. Experiments were performed in a test room of 5.5 m (length) x 3.8 m (width) x 3.2 m (height) with symmetrical set-up of cylindrical heat sources that gave a thermal load of 40–80 W/floor-m2. The ventilation air was supplied through a diffuse ceiling with 0.5% degree of perforation. The observations indicate that the mean air speed and the airflow fluctuation increase with thermal load. Furthermore, the results show that a range of length scales increases with thermal load and with mean air speed. The results indicate that it can be difficult to fulfill the standard air velocity criteria for highly occupied spaces, where the maximum allowable mean air velocity is relatively low, i.e. 0.15–0.20 m/s. This is because the buoyancy flows from heat sources accelerate locally the flow field.

      PubDate: 2017-12-13T08:49:20Z
       
  • Stakeholder impact analysis during post-occupancy evaluation of green
           buildings – A Chinese context
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Hongyang Li, S. Thomas Ng, Martin Skitmore
      The high-energy consumption of the architectural, engineering and construction (AEC) industry and associated environmental pollution have become a global challenge, and governments at different levels in China have been dedicated to improving the industry's sustainability. However, although the concept of green building (GB) has been growing rapidly, the primarily emphasis has been on energy-saving design with little attention paid to sustainable post-occupancy operations, which is hindering further development. To address this fundamental issue it is necessary to evaluate the post-occupancy performance of GB and, given China's current circumstances, one that involves the participation of all stakeholders to avoid being dominated by construction professionals. However, such participatory evaluations are currently very limited and perfunctory in the country, usually involving simply informing or placating the stakeholders. In response, this paper develops a comprehensive quantitative method to analyze stakeholder impact during GB post-occupancy evaluation (POE). This enables the various stakeholder groups to be prioritized in terms of their influence levels and hence contributes to maximizing overall stakeholder satisfaction by improving the efficiency and effectiveness of the evaluation. The findings of the paper are expected to help clients and design teams improve their building designs by integrating the views of stakeholders through the POE in order to realize the true spirit of GB development.

      PubDate: 2017-12-13T08:49:20Z
       
  • Customizing well-known sustainability assessment tools for Iranian
           residential buildings using Fuzzy Analytic Hierarchy Process
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Esmaeil Zarghami, Hamidreza Azemati, Dorsa Fatourehchi, Mohammad Karamloo
      The aim of this research is to customize the categories and criteria points of well-known sustainability assessment tools regarding the priorities in sustainability concerns of Iran in order to develop an Iranian sustainability assessment tool suitable for residential buildings. Therefore, common sustainability indicators of LEED, BREEAM, CASBEE and SBTool will be used as benchmarks for the evaluation process by Iranian professional experts to revise the points allocated in Iranian assessment tool. For the revision of the points in accordance with Iranian sustainability needs, FAHP method (Fuzzy Analytical Hierarchy Process) will be conducted. Afterwards, Iranian sustainability assessment tool, consisting of six levels of certification with categories and criteria points, has been designed to promote sustainability in the residential buildings. The reliability of the assessment tool has been confirmed by comparing performance sensitivity with the existing assessment tools in terms of the points given to each category. This will encourage Iranian construction practitioners to be more aware of worldwide sustainability assessment tools and of the way to implement sustainability in their residential building projects. Results can be a basis for further investigations on other indicators which are crucial for sustainability concerns of Iran and would provide a platform for inspiration of further sustainability solutions. Introduction of the priority weights of sustainability fundamentals will be a reference for further developing a more holistic assessment tool, considering more dimensions such as economic and social sustainability issues regarding Iranian residential buildings.

      PubDate: 2017-12-13T08:49:20Z
       
  • Investigation into sensitivities of factors in outdoor thermal comfort
           indices
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Zhaosong Fang, Zhang Lin, Cheuk Ming Mak, Jianlei Niu, Kam-Tim Tse
      With the development of the urban city, increasing attention has been paid to outdoor thermal comfort. In this paper, an analysis of the sensitivities of different factors, including the personal factors and physical parameters of the thermal environment was conducted. The results showed that there was a strong linear relationship between the Physiological Equivalent Temperature (PET) and operation temperature. When the operation temperature was lower than 32 °C, the effect of air velocity on the PET was positive. However, the effects of other factors, including relative humidity, clothing insulation, and metabolic rate, on the PET were insignificant. An exponential relationship was found between the UTCI and the operation temperature. The effect of air velocity change on the UTCI became weaker and weaker with the increase of operation temperature. Compared with the PET, the linear relationship between the UTCI and relative humidity was clearer. A field survey of thermal comfort carried out in Guangzhou University was used for the validation of the thermal comfort models. It was observed that the clothing insulation requirement increased with the decrease of air temperature in autumn. The variations in metabolic rate were also obvious, from 1met to 3.8 met. More than 70% of the people had been walking before they arrived at the survey locations. In addition, there were some differences in the neutral PET and UTCI temperature between the metabolic rates of 1.0–2.0 met and of 2.6 met. Meanwhile, models of MTSV against the PET and UTCI under different metabolic rates were established.

      PubDate: 2017-12-13T08:49:20Z
       
  • Thermo-active building systems and sound absorbers: Thermal comfort under
           real operation conditions
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Benjamin Köhler, Nils Rage, Pierre Chigot, Christian Anker Hviid
      Radiant systems are established today and have a high ecological potential in buildings while ensuring thermal comfort. Free-hanging sound absorbers are commonly used for room acoustic control, but can reduce the heat exchange when suspended under an active slab. The aim of this study is to evaluate the impact on thermal comfort of horizontal and vertical free-hanging porous sound absorbers placed in rooms of a building cooled by Thermo-Active Building System (TABS), under real operation conditions. A design comparing five different ceiling coverage ratios and two room types has been implemented during three measurement periods. A clear correlation between increase of ceiling coverage ratio and reduction of thermal comfort could not be derived systematically for each measurement period and room type, contrarily to what was expected from literature. In the first two monitoring periods in the larger office rooms, rooms with higher coverage ratios reported higher operative temperatures. This correlation was however not clear from the monitoring in the smaller offices and other measurement periods. In all monitored rooms, a strong influence of the user behaviour on thermal comfort has been observed. A higher temporal offset between ceiling and operative temperature was also observed in rooms equipped with absorbers.

      PubDate: 2017-12-13T08:49:20Z
       
  • Investigation of indoor thermal comfort in warm-humid conditions at a
           German climate test facility
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Michael Kleber, Andreas Wagner
      As a result of climate change outdoor temperature and humidity are predicted to increase within the next decades in Germany, especially in the Upper Rhine area. As indoor summer conditions will be affected by this change, responses of 136 subjects to warm-humid conditions have been investigated in a test-facility at the Karlsruhe Institute of Technology (KIT). Nine experimental conditions with high operative temperature (to) and different relative humidity (RH) levels (26 °C, 28 °C or 30 °C combined with 50%, 65% or 80%) were scheduled, with each participant experiencing two of the possible combinations. In contradiction to the German addendum of the European standard EN 15251, where a single upper limit for humidity ratio (HR) of 11.5 g/kg is recommended in summer, results indicate that human responses are additionally dependent on current temperature and other factors like thermal history. A linear regression model using operative temperature and humidity ratio is shown to describe the percentage of acceptability and is used to derive an extended comfort zone for seated activity in summer conditions (met = 1.1 and clo = 0.5). Thermal acceptance is compared to other studies (using effective temperature) and proves to be significantly lower with the German subjects than with participants who are adapted to a hot-humid climate. PMV shows underestimation of thermal sensation at elevated air humidity, up to 0.5 scale points under certain conditions.

      PubDate: 2017-12-13T08:49:20Z
       
  • A wind tunnel study of effects of twisted wind flows on the
           pedestrian-level wind field in an urban environment
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): A.U. Weerasuriya, K.T. Tse, Xuelin Zhang, S.W. Li
      The influence of twisted wind flows on the pedestrian-level wind (PLW) field of an urban area was evaluated by testing a typical urban site (Tsuen Wan, Hong Kong) in a boundary layer wind tunnel. Four twisted wind profiles with different magnitudes and directions of yaw angles were employed to investigate variations in wind speed with the properties of the twisted wind flows at the pedestrian level. An additional conventional wind profile with similar wind speeds and turbulence intensities to the twisted winds but with zero yaw angles was simulated for comparisons. The mean wind speeds at 77 locations including the perimeter, roadsides, and groups of high-rise buildings were analysed for the conventional and the four twisted wind flows. The comparisons show a tendency of twisted winds to generate higher wind speeds at the pedestrian level than the conventional wind profile. The wind speeds of the twisted winds have a strong dependence on the magnitude and direction of the yaw angles, particularly at locations where the densities of buildings in the neighbourhood are low and hence local wind circulations are significantly modified by the twisted winds.

      PubDate: 2017-12-13T08:49:20Z
       
  • Subgroups holding different conceptions of scales rate room temperatures
           differently
    • Abstract: Publication date: 15 January 2018
      Source:Building and Environment, Volume 128
      Author(s): Xaver Fuchs, Susanne Becker, Karin Schakib-Ekbatan, Marcel Schweiker
      Current thermal comfort models are fairly inaccurate at predicting occupants' thermal comfort from parameters of indoor environment. The predicted variables, thermal sensation and thermal comfort, are commonly measured using scales. These scales might themselves contribute to the problem of poor prediction due to inter- and intra-individual differences in respondents' interpretation of scales. Until now, it is unclear whether variation in scale use is systematic and potentially statistically controllable. This study investigated (1) whether there are subgroups holding different conceptions of scales and (2) whether these conceptions are associated with different ratings of sensation and comfort under experimental conditions. Sixty-three participants completed a free positioning task that assessed the relative distances between labels belonging to the ASHRAE thermal sensation scale and their distribution along various dimensions (sensation, preference, comfort, pleasantness, acceptability, and tolerability). Subsequently, the participants rated office rooms at cool, neutral, and warm conditions regarding the same dimensions. Latent class regression on the free positioning task revealed subgroups showing distinct and interpretable patterns such as preferences for different temperature ranges. Remarkably, these patterns were mirrored in the participants' ratings under the experimental thermal conditions. The results suggest the existence of different conceptions concerning the relationships between the labels of the ASHRAE scale. The prediction of participants' ratings of thermal conditions in concrete situations can be significantly improved when taking these conceptions into account.

      PubDate: 2017-12-13T08:49:20Z
       
  • Fast-growing bio-based materials as an opportunity for storing carbon in
           exterior walls
    • Abstract: Publication date: Available online 11 December 2017
      Source:Building and Environment
      Author(s): Francesco Pittau, Felix Krause, Gabriele Lumia, Guillaume Habert
      Storing carbon in construction products and building components seems a particularly attractive strategy for compensating the initial greenhouse gas (GHG) emissions from production and construction. Typically, in LCA methods, when a sustainable forestry management is assumed, biogenic carbon is not included in the calculation since forest products are considered as carbon neutral due to the full regeneration of biomass in forest at the end of a rotation period. The purpose of this article is to investigate the effect of storing carbon in biogenic materials and lime-based products when they are used as construction materials and left long in a building. Five different alternative exterior walls with different construction technologies are compared. In the first two alternatives (STR and HEM), a significant amount of fast-growing biogenic material is used as thermal insulation, while the third (TIM) represents a typical timber frame structure with mineral insulation. The last two are traditional wall alternatives based on bricks (BRI) and cast concrete (CON) with an additional external thermal insulation composite system (ETICS) in EPS. A model based on a dynamic LCA is adopted to include timing in the calculation. The results, expressed in terms of radiative forcing in the atmosphere, show that storing carbon in fast-growing biogenic materials is much more efficient than in timber elements. The carbon stored in fast-growing biogenic materials is fully captured by crop regrowth only one year after construction, while a longer time is expected for forest products due to the long rotation period required for forest regrowth.

      PubDate: 2017-12-13T08:49:20Z
       
  • Using a chain recooling system on buildings in hot and humid climates
    • Abstract: Publication date: Available online 11 December 2017
      Source:Building and Environment
      Author(s): Wei-Jen Chen, David E. Claridge, Jiajun Liao
      In hot and humid climates, warm outside air with rich moisture content impacts several aspects of building operation. To meet the ventilation requirement while maintaining indoor relative humidity (RH) at the desired level, dehumidification is usually required. This is typically done by cooling the air to 55 °F (12.8 °C). However, if the zone cooling load is low, then inefficient reheat may be necessary to maintain the indoor temperature set-point. To achieve better system efficiency, a new HVAC system concept called the "Chain Recooling System" is proposed. In this paper, it is shown that compared to a conventional Single Duct Variable Air Volume (SDVAV) system, the proposed system has the potential to provide better indoor air quality, eliminate the reheat requirement, and reduce fan energy consumption. To demonstrate the advantages of the proposed system, a building on the Texas A&M University campus in College Station, TX, is selected as a case study. It is projected that the HVAC system related energy consumption would be reduced by 15.2% and the average contaminant level would be reduced by 27% if the SDVAV system were replaced by the CRS without sacrificing comfort in the individual zones.

      PubDate: 2017-12-13T08:49:20Z
       
  • Biomimetic duct tee for reducing the local resistance of a ventilation and
           air-conditioning system
    • Abstract: Publication date: Available online 9 December 2017
      Source:Building and Environment
      Author(s): Ran Gao, Kaikai Liu, Angui Li, Zhiyu Fang, Zhigang Yang, Beihua Cong
      The energy consumption of air transportation and distribution systems in ventilation and air-conditioning ducts has drawn worldwide attention. In this study, a method for reducing the local resistance in a duct tee using a protrusion structure is proposed based on biomimicry of the branched structure of plants. The resistance of a duct featuring protrusions is compared with that of the five traditional types of tees. The resistance mechanism of the protrusion structure is analyzed, and the effectiveness of the proposed method is verified through experiments. The resistance of a duct tee with protrusions is much smaller than that of all traditional tees. Relative to the traditional duct tee, the resistance reduction rates of the duct tee with protrusion structure in two flow directions are 36% and 21%. In cases of high flow and low aspect ratios, the resistance becomes negative; that is, the resistance reduction rates are greater than 100%. The protrusions significantly reduce the energy dissipation rate of the duct tee. The effect region of the energy dissipation for duct tees is smaller than that of traditional tees.

      PubDate: 2017-12-13T08:49:20Z
       
 
 
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