scholarly journals Numerical Investigation of the Influence of Vegetation on the Aero-Thermal Performance of Buildings with Courtyards in Hot Climates

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5388
Author(s):  
Hao Sun ◽  
Carlos Jimenez-Bescos ◽  
Murtaza Mohammadi ◽  
Fangliang Zhong ◽  
John Kaiser Calautit
Keyword(s):  
Thermal Comfort ◽  
Thermal Performance ◽  
Natural Ventilation ◽  
Spatial Configuration ◽  
Environmental Parameters ◽  
Comfort Levels ◽  
Indoor Comfort ◽  
The Impact ◽  
Indoor Spaces ◽  
Good Agreement

Natural ventilation is an energy-efficient way to provide fresh air and enhance indoor comfort levels. The wind-driven natural ventilation in courtyards has been investigated by many researchers, particularly the influence of the spatial configuration and environmental parameters on the ventilation and thermal comfort performance. However, previous research has mainly focused on the courtyard region instead of the indoor spaces surrounding it. Additionally, as a microclimate regulator, courtyards are rarely assessed in terms of the impact of vegetation, including its impact on energy consumption and thermal comfort. Evapotranspiration from vegetation can help lower air temperature in the surrounding environment and, therefore, its influence on the ventilation and thermal comfort in buildings with courtyards should be evaluated. The present study investigates the impact of vegetation on the aero-thermal comfort conditions in a courtyard and surrounding buildings in hot climates. Computational fluid dynamics was employed to evaluate the aero-thermal comfort conditions of the courtyard and surrounding buildings with different configurations of vegetation. The modeling was validated using previous works’ experimental data, and good agreement was observed. Thermal comfort indices were used to assess thermal performance. The study also evaluated the cover, height and planting area of vegetation in the courtyard. The results of this study can help develop tools that can assist the addition of vegetation in courtyards to maximize their effects. Future works will focus on looking at the influence of the strategies on different designs and layouts of courtyards.

scholarly journals Application of thermal comfort assessment models to indoor areas near glazed walls – experimental evaluation

2021 ◽  
Vol 20 (1) ◽  
pp. 106-127
Author(s):  
António Manuel Figueiredo Freitas Oliveira ◽  
◽  
Helena Corvacho ◽  
Keyword(s):  
Solar Radiation ◽  
Thermal Comfort ◽  
Thermal Environment ◽  
National Laboratory ◽  
Environmental Parameters ◽  
Outdoor Environment ◽  
Assessment Model ◽  
Indoor Space ◽  
The Impact ◽  
Indoor Spaces

In this paper, some of the results of an experimental study are presented. Its purpose was to better understand the impact of glazing on thermal comfort of users of indoor spaces (living and working), especially in the areas near glazed walls. Glazed elements, such as windows and glazed doors, allow visual access to the outdoor environment and the entrance of natural light and solar heat gains but they are often the cause of unwanted heat losses and gains and are disturbing elements in obtaining thermal comfort, both in global terms and in what concerns local discomfort due to radiant asymmetries and/or air draughts. Furthermore, solar radiation directly affecting users in the vicinity of glazing can also cause discomfort. These disturbances are recognized by users, both on cold winter days and on hot summer days. To assess thermal comfort or thermal neutrality of a person in a particular indoor space, it is important to know their location within that space. Thus, in order to adequately assess thermal comfort in the areas near the glazing, the indoor thermal environment must be characterized for this specific location. In this study, two indoor spaces (a classroom and an office-room) of a school building were monitored at different periods of the year. The measurements of the environmental parameters were performed both in the center of the rooms and in the areas near the glazing. Five models of thermal comfort assessment were then applied to the results, in order to compare the comfort conditions between the two studied locations and to evaluate the applicability of these models to the areas close to glazed walls. It was observed there was clearly a greater variability of comfort conditions in the vicinity of the glazed walls when compared to the center of the rooms. The application of thermal comfort assessment models to the two studied rooms was able to reveal the differences between the two compared locations within each space. It was also possible to show the effect of incoming solar radiation and the influence of the geometry of the spaces and of the ratio between glazed area and floor area by comparing the results for both spaces. The assessment model proposed by LNEC (Portuguese National Laboratory of Civil Engineering) proved to be the most adapted to Portuguese users’ habits.

The Impact of Passive Design on Building Thermal Performance in Hot and Dry Climate

2012 ◽  
Vol 37 (3) ◽  
pp. 81-91
Author(s):  
Emad S. Mushtaha ◽  
Taro Mori ◽  
Enai Masamichi
Keyword(s):  
Thermal Performance ◽  
Natural Ventilation ◽  
Integrated Design ◽  
Solar Panels ◽  
Basic Principles ◽  
New Development ◽  
Passive Design ◽  
Shading Devices ◽  
The Impact ◽  
Indoor Spaces

Several calls have been everywhere asking for proper use of passive design tools like shading devices, insulation, natural ventilation and solar panels in building architecture of hot-dry area in order to improve the thermal performance of indoor spaces. This paper examines the effect of these passive tools on indoor thermal performance which in turn helps arrange thermal priorities properly. Herein, basic principles of Successive Integration Method (SIM) have been utilized for an integrated design of two floors with small openings integrated with floor cooling, solar panels, natural ventilation, shading devices, and insulation. As a result, create priorities of passive tools that are structured consequently for ventilation, insulation, solar panels, and shading devices. This structure could guide designers and builders to set their priorities for the new development of building construction.

Thermal performance comparison of different sun tracking configurations

2019 ◽  
Vol 88 (2) ◽  
pp. 20902
Author(s):  
O. Achkari ◽  
A. El Fadar
Keyword(s):  
Thermal Performance ◽  
Electricity Generation ◽  
Arid Regions ◽  
Performance Comparison ◽  
Water Desalination ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
The Impact ◽  
The Mathematical Model ◽  
Good Agreement

Parabolic trough collector (PTC) is one of the most widespread solar concentration technologies and represents the biggest share of the CSP market; it is currently used in various applications, such as electricity generation, heat production for industrial processes, water desalination in arid regions and industrial cooling. The current paper provides a synopsis of the commonly used sun trackers and investigates the impact of various sun tracking modes on thermal performance of a parabolic trough collector. Two sun-tracking configurations, full automatic and semi-automatic, and a stationary one have numerically been investigated. The simulation results have shown that, under the system conditions (design, operating and weather), the PTC's performance depends strongly on the kind of sun tracking technique and on how this technique is exploited. Furthermore, the current study has proven that there are some optimal semi-automatic configurations that are more efficient than one-axis sun tracking systems. The comparison of the mathematical model used in this paper with the thermal profile of some experimental data available in the literature has shown a good agreement with a remarkably low relative error (2.93%).

Optical properties of traditional clay tiles for ventilated roofs and implication on roof thermal performance

2018 ◽  
Vol 42 (4) ◽  
pp. 484-505 ◽  
Author(s):  
Elisa Di Giuseppe ◽  
Simona Sabbatini ◽  
Nikita Cozzolino ◽  
Pierluigi Stipa ◽  
Marco D’Orazio
Keyword(s):  
Optical Properties ◽  
Thermal Performance ◽  
Temperate Climate ◽  
Second Phase ◽  
Analysis Tool ◽  
Urban Heat ◽  
Indoor Comfort ◽  
The Impact ◽  
Clay Tiles ◽  
Warm Temperate

A remarkable advantage of clay tiles roof coverings in hot climates is the realization of a ventilated air layer between them and the roofing underlay that allows a natural and forced convection through the tiles joints and the channel from eaves to ridge, thus cooling the roof materials. However recently, in many countries, regulatory developments on buildings energy efficiency or buildings sustainability certification protocols are increasingly encouraging the use of alternative strategies, with the aim of reducing the urban heat island (UHI) effect and the buildings’ cooling consumptions. Among them, the use of ‘cool’ materials for roof covering. These mandatory or voluntary measures de facto push the construction products market towards specific directions, risking penalizing traditional components such as clay tiles. This article reports the results of experimental and numerical activities carried out in order to extensively characterize the optical properties of clay tile materials and investigate their impact, also coupled with above sheathing ventilation, on the thermal performance of a ventilated roof under warm-temperate climate. In the first phase of the research, the main optical properties of over 30 different clay products have been experimentally characterized in order to get a clear and extensive picture of such properties for the materials spread in the market. In a second phase, starting from the thermal data collected on an experimental real-scale building, a dynamic energy analysis tool was calibrated and used to perform simulations by varying the optical properties of the roof covering thus assessing the impact on the roof temperatures, also in comparison to a clay tiles roof. The results underline that the use of the above sheathing ventilation obtained through clay tiles is an effective strategy to reduce roof temperatures, even if covering materials are not qualified as ‘cool’, thus impacting on both UHI and indoor comfort.

scholarly journals User Thermal Comfort in Historic Buildings: Evaluation of the Potential of Thermal Mass, Orientation, Evaporative Cooling and Ventilation

2020 ◽  
Vol 12 (22) ◽  
pp. 9672
Author(s):  
Mamdooh Alwetaishi ◽  
Ashraf Balabel ◽  
Ahmed Abdelhafiz ◽  
Usama Issa ◽  
Ibrahim Sharaky ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
High Altitude ◽  
Air Temperature ◽  
Thermal Performance ◽  
Indoor Air ◽  
Computer Modelling ◽  
Evaporative Cooling ◽  
Comfort Level ◽  
Thermal Mass ◽  
The Impact

The study investigated the level of thermal comfort in historical buildings located at a relatively high altitude in the Arabian Desert of Saudi Arabia. The study focused on the impact of the use of thermal mass and orientation on the level of thermal performance at Shubra and Boqri Palaces. Qualitative and quantitative analyses were used in this study, including a questionnaire interview with architecture experts living at the relatively high altitude of Taif city, to obtain data and information from local experts. The computer software TAS EDSL was used along with on-site equipment, such as thermal imaging cameras and data loggers, to observe the physical conditions of the building in terms of its thermal performance. The study revealed that the experts’ age and years of experience were important aspects while collecting data from them during the survey. The use of thermal mass had a slight impact on the indoor air temperature as well as the energy consumption, but it helped in providing thermal comfort. Use of ventilation can improve thermal comfort level. Evaporative cooling technique has a considerable impact on reducing indoor air temperature with 4 °C drop, improving the thermal comfort sensation level. The novelty of this work is that, it links the outcomes of qualitative results of experts with field monitoring as well as computer modelling. This can contribute as method to accurately collect data in similar case studies.

scholarly journals Evaluation of Basement's Thermal Performance Against Thermal Comfort Model at Hot-arid Climates, Case Study (Egypt)

2017 ◽  
Vol 2 (1) ◽  
pp. 24
Author(s):  
Heba Hassan Kamel ◽  
Daisuke Sumiyoshi
Keyword(s):  
Iterative Method ◽  
Thermal Comfort ◽  
Thermal Performance ◽  
High Energy ◽  
Mean Bias Error ◽  
Comfort Levels ◽  
Diurnal Range ◽  
Energy Plus ◽  
Thermal Comfort Model

Reaching thermal comfort levels in hot-arid climates is becoming more difficult nowadays without the use of high energy consuming mechanical systems. Therefore, the need to use effective passive energy design techniques such as earth-sheltered buildings is becoming greater. This paper combines researches that uses monitoring and simulations in order to evaluate basements’ thermal performance that reached thermal comfort levels without active air-conditioning systems, despite the harsh climate conditions. The case study was conducted in Al-Minya city, Egypt, which is known for its high diurnal range. The study calibrated a non-conditioned basement simulation model versus the monitored data to simulate its thermal performance. The greatest challenge was to calculate the ground temperature. To do this successfully, we used an iterative approach between packages of the basement preprocessor and Energy Plus / Design Builder until reaching a convergence. The iterative method results showed significant agreement between the measured and modeled data; with a correlation of 98 percent and errors with mean bias error and normalized root mean square error of -1.0 and 7.6 percent; respectively. On the other hand, the Energy Plus method, integrating the Xing approach, showed significantly divergent results between the simulated models versus the measured data. The calibrated model analysis evaluation, using the Fanger’s thermal comfort model, showed satisfactory results within the thermal comfort sensation range. The research results significance indicates that the precise customized detailed iterative method is essential to create the needed inputs which subsequently lead to near-to-actual outputs compared with other ground-contact simulation methods. In fact, the precise customized detailed iterative method approach may be used as a benchmark for simulators for easy and precise ground temperatures’ calculations and earth-sheltered buildings’ simulations.

scholarly journals An adaptive thermal comfort model for naturally ventilated classrooms of technical institutions in Madurai

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Subhashini S. ◽  
Thirumaran Kesavaperumal ◽  
Masa Noguchi
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Higher Learning ◽  
Educational Institutions ◽  
Climatic Region ◽  
Content Type ◽  
Comfort Levels ◽  
Neutral Temperature ◽  
Adaptive Comfort ◽  
Temperature Levels

Purpose Occupants dwelling in hot climatic regions of India for a longer term are tolerable to high temperature levels than predicted by American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards. The purpose of this study is to evaluate the thermal sensations (TS) and neutral temperature of the occupants in naturally ventilated (NV) and air-conditioned (AC) classrooms of two technical institutions located in the same premises in the suburbs of Madurai. The main focus of this study is to understand the occupants’ behaviour in response to the thermal conditions of the educational buildings particularly in the warm and humid climatic zone of Madurai. Design/methodology/approach This research collected data through field studies. The data included 383 survey questionnaires from NV classrooms and 285 from AC classrooms, as well as on-site measurements of interior and exterior weather conditions. The TS results show that the students preferred well-designed NV classrooms than AC classrooms. A new adaptive comfort equation derived from this study can be applied to NV classrooms in warm and humid climates where mean outdoor temperature exceeds 40°C. Findings The neutral temperature derived for NV classrooms in Madurai ranged from 29°C to 34°C. Thus, the occupants in the NV classrooms of the higher learning educational institutions in the warm and humid climatic region of Madurai can adapt well to higher indoor temperature levels than predicted by ASHRAE comfort levels with minimum adjustments. Research limitations/implications The study was limited to only occupants in two premier higher learning technical educational institutions located in Madurai region within 5–10 km within the city limits to understand the implications of microclimate with respect to the urban context. Thus, further research is required to examine the tendency under local conditions in other regions beyond those applied to this study. Social implications The findings of this study showed that occupants in higher learning educational intuitions in Madurai prefer NV classrooms than AC classrooms. Therefore, with rising demands of energy use for mechanical ventilation and the associated high cost for running AC buildings, architects should prioritize the design of energy efficient buildings through the optimal use of passive design strategies for ventilation and thermal comfort. This study gives a base data for architects to understand the adaptive limitations of occupants and design NV buildings that can promote natural ventilation and provide better thermal environments that can help increase the productivity of students. Originality/value This paper was an attempt to develop the adaptive comfort model for NV classrooms in Madurai regions. There has been no attempt to identify the adaptive comfort levels of occupants in higher learning technical educational institutions located in warm and humid climatic region of India.

scholarly journals Investigate the impact of a low u-value framing condition and an insulated curb condition at cantileverd concrete balcony slabs in high-rise MURBS

2021 ◽  
Author(s):  
Chafik Murad
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Thermal Performance ◽  
Concrete Surface ◽  
Technical Performance ◽  
High Rise ◽  
Surface Temperatures ◽  
U Value ◽  
Thermal Bridging ◽  
The Impact

Cantilevered concrete balcony slabs are being investigated in high-rise (MURBs) to control thermal bridging in terms of energy efficiency and thermal comfort where the use of a proprietary thermal break was the prime application as a solution to improving energy efficiency. This MRP investigated the thermal performance of using a lower U-value framed glazing condition and an insulated curb condition and developed assemblies in scenarios that were simulated in THERM, and focused on the technical performance of thermal comfort benefit of insulated curb condition of 12.7 mm thick EPS. Concrete surface temperatures were significantly increased in values from 4.8 °C to 9.6 °C and from 6.2 °C to 10.0 °C above balcony slab and from 6.7 °C to 10.8 °C below slab when an insulated curb condition was used in conventional scenarios and in a lower U-value framed condition scenario with no proprietary thermal break added. U-values are reduced 10% to 18% for the upper surface of balcony slab and 4% reduction of the overall U-values when an insulated curb condition is incorporated.

scholarly journals Green Roofs as Effective Tools for Improving the Indoor Comfort Levels of Buildings—An Application to a Case Study in Sicily

2020 ◽  
Vol 10 (3) ◽  
pp. 893 ◽  
Author(s):  
Laura Cirrincione ◽  
Maria La Gennusa ◽  
Giorgia Peri ◽  
Gianfranco Rizzo ◽  
Gianluca Scaccianoce ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Electric Energy ◽  
Simulation Models ◽  
Green Roofs ◽  
Energy Performance ◽  
Comfort Levels ◽  
Indoor Comfort ◽  
The Impact

In the line of pursuing better energy efficiency in human activities that would result in a more sustainable utilization of resources, the building sector plays a relevant role, being responsible for almost 40% of both energy consumption and the release of pollutant substances in the atmosphere. For this purpose, techniques aimed at improving the energy performances of buildings’ envelopes are of paramount importance. Among them, green roofs are becoming increasingly popular due to their capability of reducing the (electric) energy needs for (summer) climatization of buildings, hence also positively affecting the indoor comfort levels for the occupants. Clearly, reliable tools for the modelling of these envelope components are needed, requiring the availability of suitable field data. Starting with the results of a case study designed to estimate how the adoption of green roofs on a Sicilian building could positively affect its energy performance, this paper shows the impact of this technology on indoor comfort and energy consumption, as well as on the reduction of direct and indirect CO2 emissions related to the climatization of the building. Specifically, the ceiling surface temperatures of some rooms located underneath six different types of green roofs were monitored. Subsequently, the obtained data were used as input for one of the most widely used simulation models, i.e., EnergyPlus, to evaluate the indoor comfort levels and the achievable energy demand savings of the building involved. From these field analyses, green roofs were shown to contribute to the mitigation of the indoor air temperatures, thus producing an improvement of the comfort conditions, especially in summer conditions, despite some worsening during transition periods seeming to arise.

A comparative study of thermal performance in three generations of Iranian residential buildings: Case studies in Csa Gorgan

2020 ◽  
pp. 174425912090624
Author(s):  
Shima Moolavi Sanzighi ◽  
Farzaneh Soflaei ◽  
Mehdi Shokouhian
Keyword(s):  
Thermal Comfort ◽  
Thermal Performance ◽  
Residential Buildings ◽  
Three Dimensional ◽  
Design Parameters ◽  
Design Strategies ◽  
Main Design ◽  
Geometrical Properties ◽  
Architectural Styles ◽  
The Impact

This article focuses on evaluating thermal performance of different types of residential buildings in Mediterranean climate (Csa) of Iran. The aim is to identify the main design parameters in nine research cases, selected from three distinct periods of history with different architectural styles, and evaluating thermal performance of these buildings. To that end, a library study was carried out to identify the most influential passive design strategies and to highlight their impact on thermal comfort and energy efficiency of residential buildings. A field survey was conducted to determine the most common types of average-income houses in Csa climate of Gorgan, Iran, with a historical overview from 19th century to present. Nine buildings were selected to study from three different period of times including the years from 1850 to 1925, 1925 to 1979 and 1979 to present. A three-dimensional numerical model was developed to assess the impact of four main design parameters including orientation, geometrical properties, openings and materials on indoor thermal comfort for each case, using Design Builder commercial software package. The correlation between these design variables and thermal comfort was presented; the results reveal that the contemporary residential buildings are not designed as efficient as traditional houses in this area, in terms of passive energy saving techniques.

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