Letteratura scientifica selezionata sul tema "Acoustic natural ventilation"

Crucial factors in window performance, such as natural ventilation and noise control, are generally conceived separately, forcing users to choose one over the other. To solve this dualism, this study aimed to develop an acoustic metamaterial (AMM) ergonomic window design to allow noise control without dependence on the natural ventilation duration and vice versa. First, the finite element method (FEM) was used to investigate the noise control performance of the acoustic metawindow (AMW) unit, followed by anechoic chamber testing, which also served as the validation of the FEM models. Furthermore, FEM analysis was used to optimise the acoustic performance and assess the ventilation potential. The numerical and experimental results exhibited an overall mean sound reduction of 15 dB within a bandwidth of 380 to 5000 Hz. A good agreement between the measured and numerical results was obtained, with a mean variation of 30%. Therefore, the AMW unit optimised acoustic performance, resulting in a higher noise reduction, especially from 50 to 500 Hz. Finally, most of the AMW unit configurations are suitable for natural ventilation, and a dynamic tuned ventilation capacity can be achieved for particular ranges by adjusting the window’s ventilation opening. The proposed designs have potential applications in building acoustics and engineering where natural ventilation and noise mitigation are required to meet regulations simultaneously.

Low speech privacy in shared and private offices in one of the early generation of a “green” building resulted in occupants' dissatisfaction. This problem is experienced in Liu institute with a natural-ventilation system. Such a system requires low air-flow resistance which is achieved by large openings which will result in noise transmission between various spaces within the building. The poor acoustical quality in this building resulted in occupants' noise complaints which were further investigated by way of relevant acoustical measurements. CATT-Acoustic software was utilized to modify the acoustical quality of the building without any disturbance to the occupants. The optimized design of the transfer box above the office door was selected based on CATT-Acoustic predictions. The acoustical measurements were conducted after installation of the transfer box above the office door. The measurements' results agreed with the predictions which led to improved speech privacy to an acceptable level between the office and the corridor in Liu Institute. More work should be done to improve the acoustical quality of natural-ventilated building to conform to ANSI standards.1The results of this study strongly support including acoustics in “green” building designs with natural ventilation to avoid users' complaints.

The pandemic has impacted every facet of our life, society, and environment. It has also affected both the requirement and challenges for acoustic research and applications. The present article attempts to present a summary of the impact of COVID-19 on several aspects of acoustics, from the changes in the sonic environment due to reduced human and industrial activities to natural ventilation requirements for mitigating the transmission of coronavirus while mitigating noise, and, more importantly, discusses the potential impacts and challenges for acoustics in the post-COVID-19 era. The present study specifically examines the effects of COVID-19 on the sonic environment, the acoustic treatment by considering the need for constant disinfection, the noise control on construction and neighborhood activities in response to an increased number of people working from home, and the need for having natural ventilation while mitigating noise at home and offices.

Expansion of brasilians cities worsen noise pollution in these places, forcing people to maintain their doors and windows closed. Domestic environment enclosing lead to necessity of air conditioning system, however the frequent use of the equipment may cause many health problems, such as respiratory difficulties and spread of diseases , not to mention high costs with energy. Considering these facts, there is the need of soundproofing windows with air supply , that allows passage of air without noise passage, guarantee a well-ventilated environment, with thermic and acoustic comfort without the use of acclimatisation systems . we have developed two prototypes with significant opening that allows air supply (passage) (0,35m2) and noise reduction (Rw+Ctr) reaching 8 to 10 dB. In the first study, we considered people inhabiting really noisy surrounding areas, who has already installed a regular window. In this particular case, we developed a soundproofing window air supply that can be installed over the existing one. A second study considered new constructions to focus the environment where the person sleeps and then elaborate a soundproofing window air supply for bedrooms.

Ducts of alternative materials to galvanised steel, are widely employed in residential buildings' mechanical ventilation systems in a bid to comply with the conservation of energy regulations in circumstances that prevent the use of natural ventilation. The noise transfer predictions of systems with alternative ducts are still being based on data for galvanised steel due to the lack of the acoustic performance data of alternative ventilation ducts tested in controlled conditions. To close this knowledge gap, alternative ventilation ducts and associated 90º bend samples were acoustically tested in controlled laboratory conditions utilising the substitution principle as outlined in BS EN ISO 7235 (2009) as well as applying a novel "zero substitution" approach. Static and dynamic tests were undertaken and sound attenuation (per meter) as a function of frequency was obtained. Preliminary results revealed the different acoustic characteristics of alternative ventilation ducts when compared to published galvanised steel ducts. The "zero substitution" approach showed good agreement with results obtained from the standardised substitution method when tested in straight duct sections. It is expected that the new acoustics knowledge on alternative ventilation ducts will influence the current design approaches and enhance confidence in noise transfer predictions resulting in cost and energy savings.

To develop sustainable cities, natural ventilation is being explored as one of the ways to reduce energy consumption and carbon dioxide emissions. Recently, acoustic metamaterials with ventilation have garnered attention for their potential to provide both ventilation and noise control. In addition, this class of acoustic metamaterials can be used as a machine enclosure for dissipating thermal load and reducing noise emission. This presentation focuses on the recent progress in acoustic metamaterials with ventilation over the last five years, highlighting three types: metamufflers, metapanels, and metacages. Furthermore, the challenges faced by metacages for real-world applications are presented.

Task of controlled ventilation in modern residential buildings is to ensure optimum quality of interior environment and fulfill hygienic and thermal technical requirements guaranteeing comfort of user. The paper discusses development and experimental verification of atypical vertical ventilation units of under pressure controlled ventilation system for residential high-rise building. Recommended concept of solution to façade detail in relation to ventilation system. Conceptual designs of alternatives of air inlet openings of under pressure controlled ventilation system for apartments of atypical vertical geometry. Optimized alternative of air inlet openings in the bottom level of vertical pilaster with function of air distribution channel for ventilation system. Laboratory experimental verification of physical properties of optimized alternative of ventilation units of under pressure controlled ventilation system in their development cycle. Hydrodynamic regime of air inlet openings of controlled ventilation system – laboratory experimental research in large rain chamber. Aerodynamic regime of natural controlled ventilation system – laboratory experimental research in large pressure chamber. Acoustic properties of natural controlled ventilation system – laboratory experimental research in acoustic chambers. Comparison by the experiment of verified parameters of ventilation units of under pressure controlled ventilation with design parameters.

The pressure differences that can be used to drive a natural ventilation system are very small and thus large apertures are required to allow sufficient air to enter and leave a building to ensure good air quality or thermal comfort. Large apertures are potential acoustic weak points on a façade and may require some form of acoustic treatment such as absorbent linings, in which case the ventilator is similar to a short section of lined duct. In ducts, the performance of absorbent linings increases with the length of lining and the ratio of the length of lined perimeter to the cross sectional area of the duct. Thus, for a duct of a given cross sectional area, a lining is more effective for a duct with a high aspect ratio than for a duct with a square cross section. However, the high aspect ratio cross section will result in greater flow resistance and impede the airflow performance. In this paper numerical methods are employed to investigate the effect of different configurations of a lined aperture on the acoustical and ventilation performance of the aperture in order to establish the optimum configurations.

Abstract Buildings that prioritize natural ventilation have problems dealing with airborne noise. The Indoor Environmental Quality (IEQ) disturbance will be considered in the school design located around the airport. As a result, the disorder can cause Sick Building Syndrome (SBS). Thus, the aspect of natural ventilation and noise (acoustics) is a problem that must be compromised. This paper will report the results of measuring the IEQ parameters of ventilation and acoustic, indicated by changes in the ratio of window openings in an elementary school located closest to the airplane runway. The results show that the top-hung type opening with a ratio of the half from the maximum opening produces airflow and noise that still does not meet the IEQ requirements. Hence the aspect of temperature and humidity and CO2 levels still meets the IEQ requirements.

Indoor environmental conditions can significantly affect occupants’ health and comfort. These conditions are especially important in educational buildings, where students, teachers and staff spend long periods of the day and are vulnerable to these factors. Recently, indoor air quality has been a focus of attention to ensure that disease transmission in these spaces is minimised. In order to increase the knowledge in this field, experimental tests have been carried out to characterise the impact of natural ventilation strategies on indoor air quality and the acoustic environment. This study has evaluated three ventilation scenarios in four different classrooms in buildings of the University of Granada, considering different window and door opening configurations. Ventilation rates were estimated using the CO2 Decay Method, and background noise recordings were made in each classroom for acoustic tests. Results show that specific natural ventilation strategies have a relevant impact that is worth considering on the background noise in indoor spaces. In this sense ventilation rates provided by the different configurations varied between 3.7 and 39.8 air changes per hour (ACH) and the acoustic tests show a background noise ranging from 43 to 54 dBA in these scenarios. Consequently, managers and teachers should take into account not only the ACH, but also other collateral impacts on the indoor environmental conditions such as the thermal comfort or the acoustic environment.

Dans les théories et pratiques architecturales et urbaines, dans les réglementations et les labels de la construction, le son est abordé principalement comme une source de bruit, de nuisance contre lequel il faut isoler le logement. Malgré cela, les constats répétés de manque de qualité sonore des lieux de vie révèlent l’insuffisance de cette approche et la nécessité d’aborder la conception sonore par des outils complémentaires.Comment introduire l’écoute dans la conception des logements collectifs afin qu’ils répondent aux enjeux de la ville de demain et participent à une bonne qualité de vie ? Les espaces intermédiaires, situés entre les écoutes de la sphère privée et celles de la dimension publique, jouent-ils un grand rôle dans les perceptions quotidiennes ? Que peut-on retenir du vécu sonore des usager.ère.s dans les formes architecturales construites qui pourrait intéresser la future écoute de la ville ?Pour y répondre, nous allons nous intéresser aux écoutes de trois catégories d’espaces intermédiaires dans des formes architecturales historiques et contemporaines : les espaces de transition (hall, cour intérieure, etc.), les espaces extérieurs aux abords des logements (terrasse partagée, toiture, balcon, etc.) et l’enveloppe bâtie (double peau, fenêtre).Pour imaginer les écoutes de la ville et du logement avec l’urbanité post-carbone nous allons nous intéresser aux sons des sociabilités, ceux du paysage naturel, aux sons technologiques et à ceux des mobilités. Dans la prospective d’une ville aux nombreux aléas climatiques, nous imaginons une diversité d’usages et de cultures, des programmations mixtes, des mobilités douces (moteurs hybrides et électriques notamment), des proximités et des voisinages apportés par la densité. Les épisodes caniculaires annoncés nécessitent dès à présent de penser à des moyens de rafraîchir les logements. Comment va-t-on pouvoir vivre dans la densité avec les sons du dehors ? Comment rafraîchir un logement par une ventilation naturelle tout en apportant une modulation de l’écoute ?Cette thèse, réalisée dans le cadre d’un contrat A.N.R.T.-C.I.F.R.E. au sein du B.E.T. LASA, est rattachée au laboratoire A.A.U.-CRESSON et à la chaire de recherche « Habitat du futur ». Nous sommes convaincus de l’importance de l’expérimentation pour répondre à l’ensemble de ces questions et intégrer l’écoute dans la pratique de l’architecture. C’est pourquoi nous testerons des outils concrets et appréhensibles par les acteur.ice.s d’un projet. Une analyse d’un projet à Villeurbanne (69), le macro-lot B, sera réalisée dès les premières phases de conception pour anticiper ses ambiances sonores et les modulations d’écoute qu’il pourrait apporter. La conception d’un prototype à échelle 1:1 d’ECHAfaudage SONore – ECHASON – visera à expérimenter ses futures ambiances depuis un logement ventilé naturellement et depuis ses espaces intermédiaires. N’ayant pas pu être réalisé dans sa taille maximale, ce seront finalement deux prototypes de dispositifs de ventilation naturelle intégrant un filtrage sonore qui ont été construits et expérimentés avec des acteur.ice.s du projet. Plusieurs bandes sonores anticipant des espaces intermédiaires du macro-lot B ont pu être expérimentées avec des futur.e.s habitant.e.s de ce projet. Les résultats obtenus ont permis d’aboutir à l’ébauche de trois cahiers des charges pour intégrer la dimension sonore dans les futurs concours d’architecture et d’urbanisme. La qualité de l’environnement sonore doit être intégrée à la conception des logements au même titre que les préoccupations sur l’ensoleillement, la qualité de l’air ou encore le confort d’été. Cela représente un enjeu social, économique et sanitaire. C’est en cela que ce travail défend l’idée d’une conception des logements par l’écoute qui ne se fasse plus uniquement de manière défensive ou corrective mais plutôt de manière créative et engagée
In architectural and urban theories and practices, in building regulations and labels, sound is approached primarily as a source of noise and nuisance, against which housing must be insulated. Despite this fact, repeated reports of a lack of sound quality in living spaces have revealed the inadequacy of this approach, and the need for complementary tools to address sound design.How can we introduce listening into the design of multi-family housing so that it meets the challenges of tomorrow's city and contributes to a good quality of life? Do intermediate spaces, located between the private and public spheres, play a major role in everyday perceptions? What can we learn from users' experience of sound in built architectural forms that might be of interest to future city listening?To answer this question, we're going to look at three categories of intermediate spaces in historic and contemporary architectural forms : transitional spaces (hall, inner courtyard, etc.), outdoor spaces around dwellings (shared terrace, roof, balcony, etc.) and the envelope of the building (double skin, window).To imagine the sounds of the city and housing in post-carbon urbanity, we're going to look at the sounds of sociability, the sounds of the natural landscape, technological sounds and the sounds of mobility. Looking ahead to a city with many climatic hazards, we imagine a diversity of uses and cultures, mixed-use programming, soft mobility (hybrid and electric motors in particular), proximity enhanced by density. With heatwaves on the horizon, we need to start thinking about ways on how cooling our homes. How can we live in density with the sounds of the outside world ? How can we cool a home with natural ventilation, while at the same time modulating the listening experience ?This thesis, carried out under an A.N.R.T.-C.I.F.R.E. contract within the B.E.T. LASA, is linked to the A.A.U.-CRESSON laboratory and the "Habitat of the Future" research chair. We are convinced of the importance of experimentation in answering all these questions and integrating the listening experience into the practice of architecture. That's why, throughout this work, we'll be experimenting with concrete tools that can be grasped by those involved in a project. An analysis of a project in Villeurbanne (69), the « macro-lot B », will be carried out in the early design phases to anticipate its sound ambiances and the listening modulations it could bring. The design of a 1:1 scale prototype of ECHASON - ECHAfaudage SONore - will be intended to experiment with its future environment of a naturally ventilated dwelling and from its intermediate spaces. As the project could not be carried out to its maximum size, two prototypes of natural ventilation systems incorporating sound filtration were built and tested with the project's actors. Several soundtracks anticipating the intermediate spaces of macro-lot B were tested with future residents of the project. The results led to the drafting of three specifications for integrating the sound dimension into future architectural and urban planning competitions. The quality of the sound environment must be integrated into housing design in the same way as concerns about sunlight, air quality and summer comfort. This represents a social, economic and health issue. In this perspective, this work defends the idea of designing housing through listening, not anymore in a defensive or corrective way, but rather in a creative and committed way

Natural ventilation is being adopted in building design to reduce building operational energy usage and increasing building occupant comfort. Unfortunately, ventilation openings in interior partitions of naturally ventilated buildings also reduce the noise isolation across the partition, resulting in a poor acoustical environment – for example, insufficient privacy and excessive annoyance. This work moves toward an understanding of, and design methodology for, interior natural ventilation opening silencers which will allow design optimization for both airflow and noise isolation. An optimization parameter is defined in terms of both airflow and acoustical transmission performance. Using a simple diffuse-field model, factors that affect acoustical privacy between two spaces separated by a partition are investigated, showing the relationship between ventilation opening acoustical performance and acoustical privacy. In order to maintain the privacy provided by a partition it is shown that the sound energy transmitted through the ventilation opening should not exceed 10% of that transmitted through the remainder of the partition. Ventilation openings and ventilation opening silencers in naturally ventilated buildings are studied experimentally to gain an understanding of current design practices. Airflow and acoustical performance of 19 ventilation opening and ventilation opening silencer types were measured in a purpose-built lab facility. Cross talk silencers are shown to have the highest performance of all silencer types tested. Lining the ceiling above a slot ventilation opening was measured to increase the transmission loss by 3 to 6 dB. A novel “acoustical baffle” silencer type is proposed for application when the silencer length is limited; measured performance is superior to that of an acoustical louver. Numerical acoustical and airflow modeling techniques are developed for ventilation opening silencer performance optimization and analysis work. Airflow modeling indicates that the errors associated with using a high-Reynolds number discharge coefficient are not of practical concern. By way of result synthesis, best-practice guidelines for silencer design in the context of speech privacy are provided. Select conclusions for cross talk silencers are: flow-path shape does not affect acoustical performance; straight sections before the silencer termination increase airflow performance by up to 30%; elbows in the silencer flow path reduce overall silencer performance.

The connection with the outdoor acoustic environment created by open windows has so far been one of the main impediments to the adoption of natural ventilation (NV), due to indoor noise levels easily exceeding design requirements. Starting from the apparent conflict between ventilation and acoustic comfort needs, and the potential offered by NV for low-energy cooling and ventilation, the study explores the opportunities for shaping healthy and supportive acoustic environments through sound transmitted via ventilation openings. The research question challenges the traditional approach to acoustic design, which assumes noise annoyance reduction by merely reducing decibel noise levels, drawing inspiration from the soundscape concept. Soundscape science characterises the human response to the acoustic environment in context and can help understand if and how NV may contribute to defining spaces that sound good to their occupants. The aim is to go beyond an exclusive focus on the ‘noise’ – ‘noise annoyance’ binomial, and to employ ‘wanted’ sounds as a design resource for creating acoustically pleasant environments. However, the soundscape framework, as described by ISO 12913 standard series, has been primarily developed for use in the context of urban planning. This has led to question (i) how the soundscape approach can be applied to the indoor built environment, (ii) what factors positively influence it and (iii) how it can be measured in residential buildings. A systematic literature review categorized the factors that positively influence acoustic perception in domestic environments, highlighting its strongly multi-factorial nature. Beyond noise level, a combination of acoustic and non-acoustic factors was found to affect acoustic perception, such as the urban context, house and person-related factors, socio-economic, situational, and environmental factors. The study benefited from a round of interview with experts in the field of urban soundscape, indoor soundscape, acoustic design, and public health and well-being. The collective discussion encompassed the characterization, management, and design of indoor (and indoor versus outdoor) soundscapes to identify current research gaps in the objective and subjective evaluation of the indoor acoustic environments. In response, based on a laboratory listening test, a model of perceived affective quality of indoor acoustic environments has been derived to guide the measurement and improvement of indoor residential soundscapes. During the test, 35 participants were asked to rate 20 different sound scenarios each. Scenarios were defined by combining four indoor sound sources and five urban environments, filtered through a window ajar, on 97 attribute scales. Comfort, content, and familiarity were extracted as the main perceptual dimensions explaining respectively 58%, 25% and 7% of the total variance in subjective ratings. A measurement system was proposed, based on a 2-D space defined by two orthogonal axes, comfort, and content, and two derivative axes, engagement and privacy – control, rotated 45° on the same plane. The model was tested in a large-scale online survey to assess the influences of different acoustic and non-acoustic factors on indoor soundscape dimensions, window-opening behavior, and occupant well-being. Evaluating the affective response to the indoor acoustic environment through the comfort – content model helped identifying the impacts that acoustical factors (e.g., sound typology), building (e.g., house size), urban (e.g., availability of a quiet side), situational (e.g., number of people at home), and person-related factors (e.g., noise sensitivity) determine on building occupants depending on the specific activity people are engaged with at home, reaching a more in-depth knowledge compared to appraisals based on annoyance evaluation alone. By disentangling the positive and negative contributions of sound stimuli according to people’s perception, it was possible to highlight the opportunity provided by NV to create a sense of place and enhance indoor soundscapes, providing useful masking opportunities in the presence of disturbing indoor noise sources. Results pointed to the existence of benefits from NV able to compensate for a reduced acoustic comfort in case of outdoor acoustic pollution. However, the availability of ‘positive’ urban soundscapes is essential for occupants’ well-being, and is linked primarily to access to natural sounds, but also to other commonly available urban sounds. The ‘quieter’ is therefore not always the better, but it really depends on the composition of indoor and outdoor sound types according to people’s preference and on the interaction with different domains (e.g., visual). Such evidence reinforces the role of acoustics in building and urban design, integrated with the other disciplines involved and based on multi-domain research. Overall, the doctoral study contributes to framing the ‘indoor soundscape’ concept, addressing scientific, industrial, social, and environmental implications, and suggesting future lines of research.

La ventilation naturelle est une solution passive de rafraichissement des bâtiments dont la performance est souvent limitée par des contraintes acoustiques et visuelles. Les travaux de cette thèse visent à améliorer la conception des ouvertures vitrées pour intégrer ces multiples contraintes. Des modèles thermo-aéraulique, acoustique et d'éclairement sont intégrés dans une plate-forme de simulation énergétique du bâtiment afin d'évaluer la performance de la ventilation naturelle dans des bâtiments tertiaires et résidentiels en termes de confort global et de consommation énergétique. La thèse contribue en particulier au développement et à la validation de modèles thermo-aérauliques à partir d'essais expérimentaux et de la simulation numérique. Une nouvelle technique de mesure du taux de renouvellement d'air par gaz traceur est développée en conditions de laboratoire puis appliquée dans une campagne d'essais in-situ pour caractériser l'écoulement d'air en ventilation traversante et mono-façade. Des simulations numériques ont été menées pour analyser les écarts observés entre les mesures et les corrélations. A l'aide de la CFD, des géométries d'ouverture spécifiques au cas d'étude (présence de loggia, tailles différentes de fenêtres) sous différentes conditions de vent permettent d'identifier les plages d'application des corrélations. Enfin, des simulations énergétiques du bâtiment intégrant les modèles développés et comparant différents modes de gestion sont effectuées en bâtiment de bureaux et résidentiel. On observe une réduction importante du potentiel de rafraichissement dans un environnement bruyant. Des prototypes de volets acoustiques sont conçus pour assurer un compromis entre confort thermique et acoustique. Des indicateurs applicables à la conception des ouvertures vitrées en fonction de paramètres climatiques sont également proposés
Natural ventilation is a passive solution to refresh and cool down the buildings whose performance is often limited by acoustic and visual constraints. This thesis aims to improve the design of glazed windows to integrate these multiple constraints. Thermo-aeraulic, acoustic and lighting models are integrated in a platform of building energy simulation to evaluate the performance of natural ventilation in office and residential buildings according to global comfort and energy consumption. The thesis contributes in particular to the development and the validation of thermo-aeraulic models from experiments and numeric simulations. A new technique of air change rate measurement by tracer gas is developed in laboratory conditions and then applied in an in-situ experimental campaign to characterize the airflow in cross and single-sided ventilation. The numeric simulations are conducted to analyze the deviation observed between the measures and correlations. With the help of CFD tool, the specific opening geometries of this case study (loggia, different window sizes) under different wind conditions allow to identify the application range of the correlations.Finally, building energy simulation integrating the developed models comparing different control modes are carried out for two case studies: office and residential buildings. Significant reductions of cooling potential are observed in a noisy environment. To provide a response to the constraints of external noise, prototypes of acoustic shutters are designed to ensure a good compromise between thermal and acoustic comfort. Indicators applicable to the design of glazed openings based on climatic parameters are also proposed

AbstractControlled natural ventilation in office buildings can ensure the indoor thermal comfort while reducing the life cycle energy consumption for ventilation, compared to mechanical ventilation systems (e.g. HVAC). Natural ventilation is mostly used in moderate climate zones where air conditioning is not a standard. During intermediate seasons, buildings with HVAC systems can additionally use natural ventilation to reduce energy consumption. However, in dense urban areas, natural ventilation can be problematic in terms of acoustic comfort. Here, a box-type window can serve as a compromise between thermal and acoustic comfort. Due to the more complex handling of the box-type window, an automated (electric driven) novel box-type window approach was developed within the imaF project, a part of the iCity initiative. The following article describes the basics of automated natural ventilation, acoustic characterization as well as architectural integration of this window type and the optimization of the airflow through box-type windows. The results show that the proposed geometry can provide sound insulation while providing an appropriate air exchange rate.

Over the past few decades, the concern for sustainability as a crucial component in construction has grown, as has the discussion surrounding its integration into the sector, with the purpose of achieving higher qualitative and beneficial efficiency and user experience. In the architectural field, there is a great interest in improving studies of ecological solutions that reinvent building techniques, materiality and the application of energy sources. In this research, the primary methodology employed is the case study approach, centered around the building known as The Crystal, located in London, United Kingdom. Presently, the building serves as the City Hall. In this context, the research objective is to analyze the connection between the local climate and the primary sustainable and technological strategies applied to the project. This analysis is carried out through digital simulations, physical models, and critical analyses. The building was designed by Siemens as a part of the “London Sustainable Cities” program and has received recognition for its energy efficiency measures and the application of bioclimatic architecture from the beginning of its construction. This building embodies a number of sustainable development principles, including the use of geothermal heat pumps for its bioclimatic systems, renewable energy sources, the effective application of natural ventilation and highly effective materials for thermal and acoustic comfort, which, in short, convert this project into a reference within the theme of sustainability and will be studied and detailed within this research.

Maximising cross ventilation is a low energy method of naturally ventilating and providing heating and cooling to deep plan spaces. Significant reduction in the emission of greenhouse gases can be achieved through minimising the use of mechanical systems in regions with climatic conditions that support the use of natural ventilation. Arup has provided input into the design of a louvered facade for the control of external noise for Brisbane Domestic Airport. A full scale prototype facade was constructed and noise transmission loss measurements were undertaken. The results indicate that significant noise reduction can be achieved to enable compliance with the internal noise limits for airport terminals, whilst using natural ventilation. The findings from this research will directly benefit building designers and innovators in the pursuit of achieving sustainable building design.

Abstract Whenever a gas turbine is installed inside an acoustic enclosure, a ventilation system is required to cool down the package and dilute any accidental gas leakage. Due to the possible presence of gas, all items installed inside the enclosure shall be suitable and hence certified as per hazardous area requirements to prevent them from being source of ignition. For this reason, the correct operation of the ventilation system is essential to meet the certification limits and consequently to safely run the gas turbine train. A malfunction of this system can result in a reduction or a complete loss of ventilation flow in the worst case. In this event, an emergency shut down of the gas turbine train is triggered by the control system after a short transient operating condition. A robust design of a gas turbine package shall also consider such transient condition of ventilation loss to encompass all possible operating scenarios and to verify that each item stays within the certification limits during this time frame. Furthermore, each item, including the engine itself, must not fail and remain ready for the next restart. Since ventilation fans are usually driven by AC power motors, AC power loss is the most common cause of ventilation loss. For this reason, Baker Hughes performed an experimental test on a full scale package of a Nova LT family turbine. The real scenario occurring in situ in case of AC loss was exactly replicated and several measurements were acquired with dedicated instrumentation installed inside the package. The purpose of this test was to check the thermal field inside the gas turbine enclosure and the amount of natural convection flow which is generated by the “chimney/stack effect”, in order to verify that the certification limits were not exceeded during the transient event of ventilation loss. Additionally, the natural convection flow inside the GT internal path (intake, engine and exhaust) was also measured to better understand the contribution given by this flow in terms of heat removal from the engine casing. Measurements confirmed that the combined effect of both flows was sufficient to guarantee an adequate ventilation cooling of the package without impacting the package design. Moreover, the naturally established flow was sufficient also to avoid any possible rotor lock in, so that the engine stays ready for restart as soon as normal conditions are restored. From the numerical point of view, a CFD model was built and run replicating the same transient scenario. The model was then fine-tuned and validated using the experimental data. In this way, having a reliable predictive method, it was also possible to simulate the natural convective flow and its related thermal field when modifications are introduced in the ventilation ducts design, as well as for gas turbine models that are different from the tested one.

Gas turbine packages provide a major portion of mechanical drive and power supply for the offshore operating oil and gas platforms. These packages are typically installed in acoustic enclosures, which need to be ventilated for both removing the heat rejected from the engine and package components, and properly diluting explosive gasses in case of a leak. Considering importance of safety and reliability of gas turbine equipment operating in the offshore environment, and also near industrial and populated areas, authors of the paper emphasize the need for experimental validation of a CFD prediction practice for effective ventilation of the turbine package enclosures. In a properly designed acoustic enclosure, ventilation system has to prevent overheating of the electrical and engine control components, as well as, dilution of potential fuel leakages to eliminate stagnant zones that could cause an ignition within enclosure. Conversely, an excessive flow of the vent air may result in masking local fuel leakages, which might pass undetected through explosion protection devices. Therefore, the optimum enclosure ventilation design has to be based on proper vent flow distribution to ensure acceptable temperature distribution within the enclosure, proper flow distribution to ensure no stagnation area, combined with appropriate gas detection setting. In order to achieve an optimum enclosure design, rather complex flow and heat transfer phenomena have to be studied to select the optimal configuration of the vent system. Numerical analysis of the enclosures with commercially available CFD codes is usually based on a number of simplifying assumptions and approximations. Therefore, to satisfy critical safety requirements in the offshore environment, authors of the paper emphasize role of experimental validation of the CFD predictions. The presented paper provides details of the enclosure design validation using a CFD study based on an earlier experimental validation of the numerical predictions. A midsize gas turbine package model was selected to demonstrate this procedure. The main features from the actual engine package were included in the CFD model. Effectiveness of ventilation was studied for both cold and heated engine surfaces. CFD analyses were also carried out for local CO2 injection emulating natural gas leakage. Both scenarios with CO2 and natural gas (methane) leakages were considered reducing uncertainty of predictions due to the differences in the density and buoyancy between these gasses. Based on presented study certain improvements in design of the enclosure were recommended and described in the paper.

This work aims to present the materials and experiments present in the prototype of the Efficient Popular House of the Federal University of Santa Maria, from the Post-Occupancy Evaluation with emphasis on the period from 2018 to 2022. Built with the goal of being a low-cost residence, the CPE is based on social interest, seeking sustainable solutions and improvements in the built environment.Therefore, the evaluation is presented from the perspective of the students living in the prototype, on the various aspects contained in a POE, such as: the subdivision and functionality of the property, the possible constructive failures, the performance of materials and devices by the use, comfort aspects:thermal, natural and artificial lighting, acoustic and natural ventilation. In addition, the study brings to the light of knowledge the functionality, limitations and potentialities of such experiments and CPE materials, presenting possible sustainable solutions for future projects.

Traditional solutions for residential buildings often focus on maximizing economic benefit at the expense of environmental and social considerations. As a result, many residential buildings are poorly ventilated, poorly insulated, and lack access to natural light and views. These factors can lead to health problems, discomfort, and energy inefficiency. This research presents an innovative model for environmentally friend housing design that maximize economic value while also considering environmental and social factors. The model is based on an applied case study of a residential development in Cairo, Egypt. The model's key features include orientation of buildings to maximize natural ventilation and daylighting - use of sustainable building materials and construction methods - provision of green spaces and other amenities for residents. The model was able to achieve significant environmental and social benefits, including reduced energy consumption - improved indoor air quality - increased comfort and well-being for residents - enhanced visual and acoustic insulation - the model is also economically viable, providing developers with a competitive advantage in the market. Overall, this research presents a promising new approach to the design of environmentally friendly housing.

The façade, or enclosure, is the primary signifier of architecture as a whole. In Rem Koolhaas’s “Elements of Architecture” the introduction to the chapter on facades states that as “a metonym for architecture … the façade is the element most invested with political and cultural meaning.” [1] Throughout history of architecture the façade has taken on and reflected the cultural and political concerns of the day. Through each period, the architect has displayed an attraction and obsession with the façade as the location of innovation in architecture. Rather than see this as relinquishing of the agency of the architect, can we reimagine the role of the skin as both mediator of its environment and active produce of it? In this essay I will be demonstrating how these questions and issues are pedagogically addressed within a coordinated undergraduate core studio. Students were asked to design three small buildings on a single site. Each project asked the students to consider a single environmental actor as its primary focus of the design. The projects leveraged architectural responses to lighting, acoustic, and thermal issues. While each building leveraged a single environmental force students soon realized that many of these systems overlapped and are codependent. The semester starts with the design of an Architecture of Light: a free standing gallery. The second project was an Architecture of Sound: a performance space that must function as a closed performance space in the winter and an open performance space in the summer. The final project was an Architecture of Heat: a spa and boat house that utilized thermal experience and natural ventilation. In this essay I will be discussing how each of these projects related to each other, what tools the students used, and where there might be opportunities for further developing this pedagogy.

Abstract A gas turbine is usually installed inside a package to reduce the acoustics emissions and protect against adverse environmental conditions. An enclosure ventilation system is keeps temperatures under acceptable limits and dilutes any potentially explosive accumulation of gas due to unexpected leakages. The functional and structural integrity as well as certification needs of the instrumentation and auxiliary systems in the package require that temperatures do not exceed a given threshold. Moreover, accidental fuel gas leakages inside the package must be studied in detail for safety purposes as required by ISO21789. CFD is routinely used in BHGE (Baker Hughes, a GE Company) to assist in the design and verification of the complete enclosure and ventilation system. This may require multiple CFD runs of very complex domains and flow fields in several operating conditions, with a large computational effort. Modeling assumptions and simulation set-up in terms of turbulence and thermal models, and the steady or unsteady nature of the simulations must be carefully assessed. In order to find a good compromise between accuracy and computational effort the present work focuses on the analysis of three different approaches, RANS, URANS and Hybrid-LES. The different computational approaches are first applied to an isothermal scaled-down model for validation purposes where it was possible to determine the impact of the large-scale flow unsteadiness and compare with measurements. Then, the analysis proceeds to a full-scale real aero-derivative gas turbine package. in which the aero and thermal field were investigated by a set of URANS and Hybrid-LES that includes the heat released by the engine. The different approaches are compared by analyzing flow and temperature fields. Finally, an accidental gas leak and the subsequent gas diffusion and/or accumulation inside the package are studied and compared. The outcome of this work highlights how the most suitable approach to be followed for industrial purposes depends on the goal of the CFD study and on the specific scenario, such as NPI Program or RQS Project.

In order to dismantle the evaporators of an obsolete reprocessing plant in Marcoule, studies were carried out by IRSN (Institut de Radioprotection et de Suˆrete´ Nucle´aire)/DSU/SERAC in cooperation with CEA (power laser group) on the laser cutting of steel structures, on the request of COGEMA (now AREVA NC)/Marcoule (UP1 dismantling project manager) and CEA/UMODD (UP1 dismantling owner). The aim of these studies was: • to quantify and to characterize the secondary emissions produced by Nd-YAG laser cutting of Uranus 65 steel pieces representative of UP1 evaporator elements and to examine the influence of different parameters, • to qualify a prefiltration technique and particularly an electrostatic precipitator, • to compare the Nd-YAG used with other cutting tools previously studied. The experiments, which took place in a 35 m3 ventilated cutting cell, allow to underline the following points: • for the Uranus 65 steel, the sedimented dross, the deposits on the walls of the cutting cell and the aerosols drawn in the ventilation exhaust duct (∼ 275 m3/h), represent respectively between 92% and 99%, between 0.01% and 0.25% and between 1% and 8% of the total collected mass, • the attached slag varies much from one configuration to the other and can sometimes amount to a relatively important fraction of the total mass, • the kerves vary from 2 mm up to 7 mm for the Uranus 65 steel plates (thickness: 13.8 mm for the single plate and 12.8 + 3.5 mm for the double plate), • the exhausted aerosol mass per cut length (g/m) decreases with the cutting speed, varies neither with the stand-off nor with the gas pressure, is dependent upon the gas nature (for the double plate), increases with the laser power, is strongly affected by the nature of the steel (stainless steel or mild steel) and is independent upon the plate position, • the size distribution of aerosols is multimodal with a main mode often around 0.45 μm, • the electrostatic precipitator has been a satisfactory prefilter in the experiments with a filtration efficiency greater than 85% and the acoustic declogging system was very useful, • compared to other cutting tools already tested in similar conditions (reciprocating saw, 50 A plasma torch, 200 A plasma torch, grinder, 1 kW laser without assistant gas, arc-air and arc saw), the 4 kW laser produced less secondary emissions than all other tools and less aerosols than the other thermal tools.