The effect of cool paints and surface properties of the facade on the thermal and energy efficiency of buildings in a hot and arid climate

The facade of a building is a decisive factor in the thermal and energy performance of buildings. Its surfaces are considered as zones of heat transfer between the inside and the outside. Surface properties, especially color and texture; which have an important role on solar absorption and thermal emittance of the facade and subsequently the thermal operation of the building. The purpose of this article is to study the impact of surface properties of the facade on the thermal comfort and energy efficiency of buildings in a hot and arid climate. The investigation is based on an experimental approach by taking measurements in test cells with an insulating paint (with nanoparticles) as well as on a numerical study by the dynamic thermal simulation software TRNSYS. Several parameters were studied such as ambient temperature, internal and external surface temperature and energy consumption. The results showed that the surfaces of the facade represent with excellence the place of heat exchange between interior and exterior whose surface properties have a colossal impact on the thermal and energy operation of the building. The insulating paint with its nanoparticles has a considerable impact on the reduction of temperature. The proper choice of material absorption has a great influence on the reduction of temperatures and energy requirements of the building

Study and optimization of the windows’ impact on thermal comfort and energy efficiency (Case of offices in a hot and arid climate)

Controlling the thermal environment and reducing the energy consumption of buildings across the façade are a difficult challenge for architects, especially in a desert climate. The windows in particular play an important role in the tandem of the thermal operation of the building and the comfort of the users. The objective of this article is to study and optimize the impact of windows, their material and proportional characteristics on the thermal comfort and energy efficiency of office buildings in a hot and arid climate. The investigation is based on an empirical approach (measurements taken in situ on real cases) as well as on a numerical simulation study with the TRNSYS program. Several parameters have been studied such as surface temperature, ambient temperature and energy consumption. The results showed that facade windows are a determining factor in the thermal exchanges between the building and its environment and that the key parameters that condition these exchanges are the windows ratio (glazed area) and the type of glazing. The judicious choice of the windows ratio combined with an appropriate choice of the type and composition of the glazing improves the thermal comfort of the users and ensures the energy performance of the building

The effect of cool paints and surface properties of the facade on the thermal and energy efficiency of buildings in a hot and arid climate

The facade of a building is a decisive factor in the thermal and energy performance of buildings. Its surfaces are considered as zones of heat transfer between the inside and the outside. Surface properties, especially color and texture; which have an important role on solar absorption and thermal emittance of the facade and subsequently the thermal operation of the building. The purpose of this article is to study the impact of surface properties of the facade on the thermal comfort and energy efficiency of buildings in a hot and arid climate. The investigation is based on an experimental approach by taking measurements in test cells with an insulating paint (with nanoparticles) as well as on a numerical study by the dynamic thermal simulation software TRNSYS. Several parameters were studied such as ambient temperature, internal and external surface temperature and energy consumption. The results showed that the surfaces of the facade represent with excellence the place of heat exchange between interior and exterior whose surface properties have a colossal impact on the thermal and energy operation of the building. The insulating paint with its nanoparticles has a considerable impact on the reduction of temperature. The proper choice of material absorption has a great influence on the reduction of temperatures and energy requirements of the building

The effect of cool paints and surface properties of the facade on the thermal and energy efficiency of buildings in a hot and arid climate

The facade of a building is a decisive factor in the thermal and energy performance of buildings. Its surfaces are considered as zones of heat transfer between the inside and the outside. Surface properties, especially color and texture; which have an important role on solar absorption and thermal emittance of the facade and subsequently the thermal operation of the building. The purpose of this article is to study the impact of surface properties of the facade on the thermal comfort and energy efficiency of buildings in a hot and arid climate. The investigation is based on an experimental approach by taking measurements in test cells with an insulating paint (with nanoparticles) as well as on a numerical study by the dynamic thermal simulation software TRNSYS. Several parameters were studied such as ambient temperature, internal and external surface temperature and energy consumption. The results showed that the surfaces of the facade represent with excellence the place of heat exchange between interior and exterior whose surface properties have a colossal impact on the thermal and energy operation of the building. The insulating paint with its nanoparticles has a considerable impact on the reduction of temperature. The proper choice of material absorption has a great influence on the reduction of temperatures and energy requirements of the building

The impact of facade materials on the thermal comfort and energy efficiency of offices buildings

In order to improve thermal comfort conditions of tertiary buildings through the facades of buildings, a research has been undertaken with the intention of developing a contextually appropriate and energetically efficient facade under the conditions of a hot and arid climate. The study has taken as its starting point the analysis of comfort conditions of a set of office buildings located in Biskra. These buildings were distinguished from standpoints of the treatment of their facades and the materials used. The study proposes to evaluate the thermal functioning of the different materials of the facade, then to optimize their behavior by acting on their material characteristics and the walls composition. The facade, indeed, represents a place of interaction and exchange between the inside and the outside, the performance of which is due to factors that are formal, material and technical. This article presents the main results of the analytical work. The investigation is based on an empirical approach (measurements in situ on real cases) as well as on a parametric simulation study. The results show that the facade represents with excellence the place of interaction and exchange between the interior and the exterior, the performance of which is due to factors that are both material and conceptual. Through a set of recommendations, this study tries to develop a material composition of high-performing facade that can respond optimally to the requirements of a tertiary building in a desert climate, while ensuring a pleasant thermal ambience and low consumption energy

Étude et optimisation de la façade pour un confort thermique et une efficacité énergétique (Cas des bâtiments tertiaires dans un climat chaud et aride)

La maitrise de l’ambiance thermique des bâtiments à travers la façade tout en minimisant la consommation énergétique est considérée comme un défi pour les concepteurs. De nos jours, ce défi est d’autant plus difficile à relever particulièrement avec les conditions climatiques et économiques actuelles qui ont fait de la performance énergétique une exigence mondiale dans tous les domaines en particulier dans celui du bâtiment. A l’instar d’autres pays, le secteur tertiaire en Algérie est considéré comme un secteur énergivore par excellence, puisqu’il détient à lui seul un taux non négligeable de la consommation énergétique. A ce titre, les immeubles de bureaux qui constituent l’essentiel du cadre bâti tertiaire, sont marqués non seulement par leur manque de confort thermique mais aussi par leur caractère énergivore à outrance dont une grande partie de l’énergie est utilisée principalement pour répondre aux besoins du confort thermique (chauffage et climatisation). Cette situation est le résultat d’une pratique architecturale indifférente au contexte où très souvent les aspects thermiques, énergétiques et les spécificités climatiques sont négligés lors de la conception. Il en résulte des impacts négatifs sur l’ambiance thermique, l’homme et l’environnement. Pour pallier à cette situation, la présente recherche s’est fixée comme objectif d’évaluer puis d’optimiser le comportement thermique des façades des immeubles de bureaux situés dans les zones chaudes et arides en prenant comme cas d’étude la ville de Biskra. Le travail d’investigation s’est focalisé précisément sur les éléments de la façade (matériaux, ouvertures, surfaces et dispositifs) afin de maitriser et d’améliorer leurs performances thermiques et énergétiques dans un contexte climatique chaud et aride. Pour ce faire, la méthodologie utilisée a été fondée sur une approche empirique (prise de mesures in situ combinée à une enquête par questionnaires) afin d’étudier le fonctionnement thermique d’un corpus de bâtiments existants. Un travail expérimental a été entrepris à travers la réalisation de quatre cellules tests à une échelle réduite a permis d’étudier les différents types de façade sous des conditions réelles. Enfin, une étude paramétrique par le logiciel de simulation thermique dynamique TRNSYS a été réalisée afin d’étudier et d’optimiser l’influence de certains paramètres. Les impacts de différents éléments de la façade sur le plan thermique et énergétique ont été étudiés, notamment : les matériaux, les dispositifs, la composition des parois, les caractéristiques des ouvertures ainsi que les propriétés surfaciques de la façade. L’étude sur terrain a été effectuée sur un corpus de neuf bâtiments représentant les typologies de façades les plus récurrentes et représentatives dans la ville de Biskra (simple, vitrée, double peau, ventilée,…). Ces bâtiments ont permis d’étudier l’influence des choix conceptuels et matériels des éléments de la façade sur le comportement thermique des constructions et la sensation des usagers. Pour sa part, l’étude expérimentale a porté sur l’exploitation d’une cellule de référence en testant trois paramètres dans les autres cellules (la performance de la surface extérieure, la double peau et la façade ventilée). Enfin, la simulation numérique a donné la possibilité d’élaborer une série de modèles pour étudier l’impact des propriétés des fenêtres (ratio, type de vitrage et facteur d’ombrage) ainsi que les propriétés surfaciques (couleur et texture) de la façade. A l’issue de ce travail, les paramètres matériels les plus influant des éléments de la façade ont pu être optimisés. Finalement, les résultats obtenus ont confirmé que la façade représente la surface d’interaction et d’échange thermique entre l’intérieur et l’extérieur dont la performance relève de plusieurs facteurs conceptuels, matériels et techniques. Des choix conceptuels appropriés relativement aux éléments de la façade qui prendraient en considération les spécificités climatiques du contexte permettent d’améliorer les ambiances thermiques des bâtiments tout en réduisant les besoins énergétiques

An Investigation on Using Passive Cooling Roofs Techniques for Improving Climatic Performance of Residential Buildings in Hot Arid Regions based on Post-Occupancy Evaluation of Inhabitants’ Thermal Comfort Appreciations

 In hot dry climates, employing passive cooling roofs systems can providecooling needs with less amount of electrical energy. Furthermore, when focusing onliving spaces in terms of indoor thermal comfort and energy performance issues,occupant’s interaction with the building should not be underestimated. Recent studieswith occupant-based focus have shown that human behaviour significantly impactsenergy consumption, even more than building design. Likewise, understandingoccupant’s interactions within buildings plays a key role in enhancing the indoorenvironment performance. To examine the potential for cooling load reduction andthermal comfort enhancement by using cool roofs in residential buildings, a study wasperformed. Considering a sample of twelve multi-story houses located in the city ofBiskra (southern Algeria), thermal comfort conditions were analysed on the basis of apost-occupancy evaluation (POE) survey and in situ recorded measurementscampaign. The POE household survey indicated that out of 43 respondents, 54%perceive indoor thermal conditions as “hot” during summer period, while 79.33% ofthem operate HVAC device day and night. Using interviews, the study also exploressocial acceptability toward implementing passive roofing techniques. Results showedthat cool roof and cool tiles were the best accepted systems with 100% and 90% votedstrongly agree. Furthermore, the potential of thermal comfort and energy-efficiencyimprovements due to cool roofs was investigated through a dynamic simulation usingTRNSYS software. Results indicated that air temperature was reduced by an averageof 4.11°C to 3.28°C, and cooling loads have decreased to 508.60kWh/m² and384.54kWh/m² respectively during the hottest period of summer. Therefore, user-centric satisfaction as a research method would enhance future buildings design

Parametric-Based Multi-Objective Optimization Workflow: Daylight and Energy Performance Study of Hospital Building in Algeria

Daylight is an important factor that significantly contributes to patients’ healing, with a reduction in the length of stay in the hospital. It can strongly affect energy consumption negatively or positively through lighting control strategies. Therefore, the case of healthcare buildings is very particular and sensitive, especially under extreme climate conditions as in hot and arid regions. The present study aims to determine a balance between daylight use and energy consumption through a parametric-based optimization of the external shading system in a typical hospital room in Biskra. This paper demonstrates how the implementation of parametric design with evolutionary algorithms is considered a reliable strategy to reach optimum solutions in building performance problems. The daylight performance is investigated based on multi-objective optimization to minimize the Energy Use Intensity “EUI”, while maximizing Spatial Daylight Autonomy “sDA” and Useful Daylight Illuminance “UDI”. A simulation model was developed via Grasshopper, which was employed with the use of Ladybug, Honeybee, and Octopus plug-ins. The results revealed that the adaptive facade system can improve indoor daylight levels and energy performance simultaneously compared to the conventional shading system. The presented framework may be used as a reference model, which can enhance opportunities to solve complex design problems in the early design stages and suggest recommendations for sustainable building design

Parametric-Based Multi-Objective Optimization Workflow: Daylight and Energy Performance Study of Hospital Building in Algeria

Daylight is an important factor that significantly contributes to patients’ healing, with a reduction in the length of stay in the hospital. It can strongly affect energy consumption negatively or positively through lighting control strategies. Therefore, the case of healthcare buildings is very particular and sensitive, especially under extreme climate conditions as in hot and arid regions. The present study aims to determine a balance between daylight use and energy consumption through a parametric-based optimization of the external shading system in a typical hospital room in Biskra. This paper demonstrates how the implementation of parametric design with evolutionary algorithms is considered a reliable strategy to reach optimum solutions in building performance problems. The daylight performance is investigated based on multi-objective optimization to minimize the Energy Use Intensity “EUI”, while maximizing Spatial Daylight Autonomy “sDA” and Useful Daylight Illuminance “UDI”. A simulation model was developed via Grasshopper, which was employed with the use of Ladybug, Honeybee, and Octopus plug-ins. The results revealed that the adaptive facade system can improve indoor daylight levels and energy performance simultaneously compared to the conventional shading system. The presented framework may be used as a reference model, which can enhance opportunities to solve complex design problems in the early design stages and suggest recommendations for sustainable building design

Exploring the Cooling Potential of Ventilated Mask Walls in Neo-Vernacular Architecture: A Case Study of André Ravéreau’s Dwellings in M’zab Valley, Algeria

This study investigates the thermal performance of the ventilated mask wall used in the low-income neo-vernacular dwellings designed by André Ravéreau to cope with the warm desert climate conditions of M’zab Valley, Ghardaia, in southern Algeria. This device is a ventilated façade provided with an opaque external massive cladding. It is designed to be particularly efficient in hot climates, functioning simultaneously as a brise-soleil and a ventilated façade, compared with conventional façade systems. Based on a typical experiment conducted during the summertime (12–14 August), a residential unit in Sidi Abbaz selected as a case study was modeled and calibrated using EnergyPlus (v8.4) software, and then a dynamic simulation was performed in order to assess the efficiency of the ventilated mask wall as a cooling strategy. By means of the validated thermal model, various alternatives for the façade materials were investigated, and the thermal behavior of the current ventilated mask wall was compared with a 45 cm thick limestone façade wall, and a 30 cm thick hollow clay brick wall under the same conditions. Countless benefits were achieved by the application of the mask wall system, including a stable and less fluctuant inner surface temperature, and a reduction in the incoming summer heat flux. The improvements performed, in particular the time lag of 12 h and the related decrement factor of 0.28 indicate the effectiveness of this wall system, which enabled radiant temperature drops of more than 10 °C, and an air temperature decrease of about 6 °C, during the summer sunniest hours. The results demonstrate that this solution is suitable for buildings design applications to meet the objective of low-energy demand in warm desert climates