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Most of the Brazilian territory is classified as a hot and humid climate, whose natural ventilation is one of the most important passive design strategies. The use of this strategy can be enhanced in the design through the shed roof air collectors or extractors. However, this strategy is not exploited by architecture design, due to the designers’ lack of knowledge about the efficiency of these devices. The article’s aim is to present guidelines for the design of shed roof air extractors and collectors, seeking to help designers to use these devices in buildings. The method is parametric studies, through CFD simulations. For the shed roof air extractors and collectors, the following is recommended: aerodynamic geometries; building with less depth and large air outlet openings. The increase in the number of sheds influences ventilation more than the change in the geometry of the sheds. For extraction, the area of the air outlet openings is the parameter that exerts the greatest influence on ventilation. For collection, the increase in the sizes of the openings of the sheds, without changing other parameters, does not significantly increase the air speed.

There are prototypes of social housing massively built in contrasting climatic conditions, generating thermal comfort needs that are difficult to satisfy by the users themselves. Variation of indoor air volume in living spaces where the use of air conditioning and natural ventilation strategies provides elements to improve thermal comfort conditions. This research shows the thermal performance located in a representative social housing according to Mexico's National Housing Commission. Operative temperature results from a benchmark case were compared to six Virtual Evaluation Models, using the Dynamic Thermal Simulation tool Design Builder® from the perspective of probability. The main objective was to determine the minimum use of active systems with different indoor air volumes and improve comfort conditions to promote sustainable living in social housing. The analysis was conducted under an adaptive comfort range according to three different climate conditions in Mexico adopting a Numerical Theoretical Method. The main findings can be divided into two parts: a) the impact of the indoor air volume on thermal performance was evidenced in a proportion of time in three representative climates of the central region of Mexico, and b) no relationship was found between indoor air volume and thermal comfort in sub-humid cold climate; in sub-humid temperate climate, the same number of comfort hours was found in two different models, and in sub-humid warm climate, an inversely proportional relationship was found between indoor air volume and the comfort hours. This findings implies a greater knowledge relative to what we know about sub-humid cold, temperate and warm climates.

This thesis consists of three different projects on flows driven by vertically distributed buoyancy sources. Following a storyline, the three serial problems have inherent connections. In the first project, a theoretical model is developed for the steady multi-layered flow induced by a plane vertically distributed buoyancy source producing a turbulent wall plume in a ventilated box. The boundary condition at the wall for each layer is established by deducing the turbulent entrainment rate. Using conformal mapping techniques and Poisson's integral theorem, closed-form solutions for the streamfunction of the induced flow in each layer are established. While the flow near the ceiling was overlooked in the classic model for the multi-layered stratification, after considering the possible flow scenarios, the stratification is reevaluated herein by incorporating an entraining ceiling current. With a markedly thinner top layer, the refined stratification matches well with available experimental observations -- agreement that was absent for the classic model -- the model overcoming the previous over-prediction in the number of interfaces. The magnitude of dimensionless flow velocity, independent of the wall buoyancy flux and physical scale of the box, decreases significantly with the number of layers. Three types of layer, each with a distinct induced flow pattern, are distinguished and their implications for indoor airflow considered. Notably, the flow in the base layer represents a continual and smooth flushing of air between the inlet opening and wall plume, whereas any intermediate layer is almost entirely comprised of near-stagnant air. Second, the linear temporal stability characteristics of a thermal plume generated along a heated vertical cylinder is investigated theoretically. Special focus is given to the uniform-wall-buoyancy-flux case whereby the cylinder surface sustains the same linear temperature gradient as the environment. A competition between the axisymmetric and helical wave modes is a remarkable feature of the instability, distinguishing these `annular wall plumes’ from free plumes/jets for which the helical mode is usually dominant. It is found that higher surface curvature stabilises the temporal axisymmetric mode significantly, but only has moderate effects on the helical mode. The most temporally unstable perturbation mode switches from a helical into an axisymmetric mode when the Prandtl number increases beyond a critical value. Both the roles of shear and buoyancy during the destabilisation are identified through an energy analysis which indicates that while (mean) shear work is usually a major source of perturbation energy, buoyancy work manifests for long-wave axisymmetric perturbation modes, and for thin cylinders and high Prandtl numbers. In heat transfer applications, to promote transition to turbulence and enhance convective heat transfer, working fluids of either sufficiently low or high Prandtl numbers are preferred; cylinders of too-small dimensionless radii should be avoided. The third project presents a numerical approach innovated to overcome the numerical difficulty of tracking the eigenmodes when evaluating a fully numerical dispersion relationship. Based on this numerical approach, the absolute/convective instability of the same annular plume as that in the second project is analysed. Following a discussion about the numerical issue of eigenmode tracking and some previous methods to alleviate it, a bespoke `initial value approach' is proposed, which primarily consists of making an estimation of the target eigenmode via solving a set of successive initial value problems, and identifying the target eigenmode from the exact solutions. Furthermore, this numerical approach is adapted into an iterative scheme, which facilitates the computation of the absolute/convective instability over the parameter space in an automatic and efficient way. For the specific temperature configuration considered herein, an annular wall plume is always absolutely stable, whereas decreasing the cylinder radius from the planar limiting case first decreases and then increases the tendency of the flow towards being absolutely unstable. The helical mode is especially susceptible to being absolutely unstable on very thin cylinders. A high Prandtl number promotes the absolute instability for both azimuthal perturbation modes. Finally, several conditions for the occurrence of plume detrainment are proposed based on the results and a hypothesis which connects the absolute instability to the detrainment phenomenon. The numerical approach also enables the absolute/convective instabilities of multiple branches of a general dispersion relationship to be computed and assessed simultaneously.

Infectious aerosol dispersion poses significant infection risks (i.e., COVID-19) in classrooms due to dense and long occupancy. Natural ventilation is an effective strategy to reduce airborne infection transmission. The building-related parameters, particularly openings, determine the natural ventilation effectiveness in reducing contaminant dispersion, necessitating an inquiry due to complex dispersion and airflow patterns. This paper investigates the correlation between window height, natural ventilation, and COVID-19 dispersion. A simulation pipeline involving a parametric 3D design environment, computational fluid dynamics (CFD), and energy simulations is developed and implemented on nine design scenarios representing different inlet-outlet heights of a free-running (no heating, cooling or mechanical ventilation) classroom. The inlet height and the inlet-outlet height difference have a considerable impact on indoor infection risk confirming that stack ventilation and the Bernoulli effect decrease indoor contaminant concentration. Proximity to openings does not ensure lower contamination levels. Proximity to the contaminant does not result in higher contamination levels.

Machine learning (ML) is a useful technique for improving building operations. However, if data can only be obtained from a target building, the data shortage will limit the use of general ML models. To overcome this issue, simplified targets and limited numbers of feature variables are required. In building engineering, building physics can be used to promote ML implementations. In this paper, a case study targeting the operation of engineered natural ventilation is performed based on energy simulations. The target issue is simplified to select the preferable opening pattern, full or half open, throughout the day. Two models using two or three feature variable types are compared. The ML method can effectively predict the correct operation scheme, even in the first year of use. The correct answer rate in the case of three variable types increases from 83% to 95% in the second year, although no significant improvement is observed in the case with two variable types. The results imply the strategy of creating a simplified model first and improving the model following data acquisition works for ML model implementation in building operations.

Introdução: O presente trabalho estima o risco de infeção por SARS-CoV-2 em ambientes interiores onde a elevada densidade de ocupação resulta numa probabilidade acrescida de contágio, como escolas, escritórios, supermercados, restaurantes e ginásios.Material e Métodos: Foram testadas várias condições nos espaços interiores, tais como a utilização e eficácia de máscaras, a ventilação, a utilização de equipamentos que permitem uma assepsia do ar recorrendo a filtros HEPA, a densidade de ocupação e o tempo de permanência nos espaços, tendo sido utilizado um modelo baseado na dispersão de partículas de aerossóis em espaços fechados e na acumulação e inalação destas partículas ao longo do tempo.Resultados: Os resultados mostraram que a substituição de máscaras sociais por máscaras com classificação FFP2 diminuiu o risco de infeção em 90% nas escolas. Em escolas com ventilação natural, a abertura das janelas na sua totalidade reduziu o risco de infeção em 64% comparativamente com o cenário de janelas fechadas. Nos espaços onde a ventilação mecânica é normalmente utilizada, a probabilidade de infeção reduziu significativamente quando os caudais de ar novo regulamentares foram duplicados (redução de 32% nos escritórios, 42% nos restaurantes, 24% nos supermercados e 46% nos ginásios). A filtragem de ar com filtros HEPA permitiu a redução da probabilidade de infeção em 72% nas escolas, escritórios e restaurantes e 61% nos ginásios. O tempo de permanência nos espaços foi também um fator relevante na variação da probabilidade de infeção, principalmente nas escolas onde se verificou que aulas mais curtas e com um maior número de intervalos reduzem o risco de infeção.Discussão: Os resultados evidenciam a importância de uma adequada ventilação em ambientes fechados, principalmente em locais onde a densidade de ocupação e os tempos de permanência são mais longos, sendo essencial a introdução de ar exterior no interior dos espaços, seja através de meios naturais ou mecânicos. É expectável que os valores de risco de infeção apresentados ao longo do trabalho estejam subvalorizados pelo facto do modelo utilizado apenas considerar a transmissão por partículas inferiores a 10 μm e por, ao assumir o distanciamento social, não incluir a transmissão de curto alcance. A vacinação não foi considerada no modelo pelo facto de ainda não estar disponível quando o trabalho foi realizado.Conclusão: Este estudo vem contribuir para a identificação de medidas que permitem um menor risco de transmissão viral, e consequentemente, uma maior segurança no interior dos espaços fechados.

Naturally ventilated double skin facade (NVDSF) utilizes solar radiation to introduce natural ventilation through a double-skin facade cavity with vents. It is an easy-to-implement green technology that can be widely applied to new or existing buildings. However, its implementation in buildings is still limited as the coupled radiation and natural convection pose challenges in predicting ventilation performance. Moreover, the diversity of real-life applications raises a great need for a universally applicable method that can account for realistic design factors. Hence, an in-depth theoretical analysis model is required to facilitate the application of NVDSFs in buildings. This study proposes two new analytical models for NVDSFs that can directly predict ventilation rates with simple inputs. Numerical simulations are also conducted to validate the developed analytical models. It demonstrated that the experimentally validated numerical model can offer accurate predictions of natural convection and radiation for the case that involved complicated environmental, structural, and material factors. Most importantly, the realistic scenarios, NVDSFs with exterior vent louvers are studied both analytically and numerically. Different optical properties from two glazing materials, regular glass and low-e glass, are also tested with the proposed analytical models. Through validation, the discrepancies of the predictions by the proposed analytical models are −5% to −9% for ‘no-louver’ NVDSF for two different glazing materials (i.e., regular and low-e glass), and 13%–27% for NVDSFs with adjustable louver angles 45°–150°.

Solar greenhouses are currently the most energy-intensive agricultural sector. In literature, there is no worldwide mapping of solar greenhouse performance under different climate scenarios. This study analyzes the performance of a Venlo solar greenhouse for 48 localities around the world. Solar greenhouses are mainly made of a transparent envelope and the effect of the direct and diffuse component of solar radiation impacts the internal plant well-being. This study aims to identify the best solution of a transparent envelope on locations with different latitudes and evenly distributed around the globe. The simulations are carried out using TRNsys, considering different thermal phenomena three-dimensional shortwave and longwave radiative exchange, airflow exchanges, presence of lamps with their exact 3D position, ground, plant evapotranspiration, and convective heat transfer coefficients. A total of 336 simulations are performed in the free-floating regime. A new index for the identification of the best glass solutions based on annual average deviation is defined. For all climates, the best glass solutions work better in winter than in summer. The optimal choice of the glass must be combined with effective scheduling of openings for natural ventilation to avoid internal overheating phenomena.

There is a rapid increase in the use of active cooling strategies for ventilation and air circulation in the recent scenario, and hence an urge of climate-responsive buildings is a need of today. Taking the advantage of local climate and designing buildings that decrease energy use can be achieved by implementing passive cooling strategies in a building. The present study focuses on how various solar passive techniques have helped in designing climate-responsive structures in the past and how its implementation can enhance the structure in modern construction techniques. By analysing structures from the past and studying the science behind them, the passive cooling effect and its development in design implementation can be examined. The paper concludes by having incited on how solar passive strategies can help to create a flexible building, responding to climatic effects and its evolution over a period of time. Keywords: Climate responsive, Hot-dry climate, passive cooling, Traditional buildings

The thermal comfort of occupants is a necessary requirement for any building. The present pandemic demands us to opt for natural ventilation over air-conditioned spaces to reduce the spread of the infection. This work aims to prevent air-conditioner usage in a commercial building in India during daytime office hours while simultaneously enhancing the thermal comfort of the building occupants through natural ventilation/Phase Change Material (PCM)/insulation techniques. Four building configurations, such as Building A (conventional building with no PCM and no insulation), Building B (building-integrated with PCM), Building C (building-integrated with insulation) and Building D (building-integrated with PCM and insulation) were analysed for various locations using DesignBuilder software. From the results, it is understood that insulation integration is recommended for locations with average nighttime temperatures greater than 27°C, while PCM integration is recommended for locations with an average nighttime temperature less than 27°C during the summer season. Also, nighttime cooling of the building through an air-conditioner is necessary for all locations during summer to maintain adequate thermal comfort with natural ventilation in the daytime. Finally, an appropriate PCM/insulation technique is recommended for an office building located in each location that falls under each type of climate. Hence, the selection of PCM/insulation technique is to be made based on the specific site conditions.

Painovoimaisen ilmanvaihdon käsitettä purkautumiskerroin selostetaan erityisesti kontrollitilavuustarkastelujen avulla mekaanisen energian taseen periaatetta soveltamalla. Yksinkertainen esimerkkitapaus esitetään. Alan terminologiaa kommentoidaan. Artikkeli on aiheeltaan opetuksellinen.

Owing to the impact of global warming, the weather becomes hotter than the past. Responding to the hot–humid climate, the Taiwan government intends to install air-conditioning in classrooms to provide comfort study environment. The thermal management of school buildings is separated into naturally ventilated and air-conditioning seasons based on the strategies of reducing energy use while maintaining thermal comfort. In this paper, the school buildings located in northern and southern Taiwan (Taipei and Kaohsiung) are selected as study objectives to simulate cooling load, thermal comfort, and the natural ventilation potential to discuss the parameters related to building envelope design. Through regression analysis of the 360 simulation cases, the Overall Thermal Transfer Value (OTTV) for Taipei and Kaohsiung are established. Besides, the coefficient of azimuth correction factor and area ratio correction factor are clarified for equivalent ventilation area. Through coupled analysis, the Pareto ranking method is used to obtain numerical solution sets corresponding to the index including OTTV and equivalent ventilation area. Consequently, a school building envelope design criteria for balancing the energy use and thermal comfort is proposed. According to the analysis results and the intersection of OTTV and equivalent ventilation area at Pareto front, it is confirmed that the restriction of the OTTV index is 20 W/m2 in Taipei and Kaohsiung; the equivalent ventilation area which guarantees no overheating risk during natural ventilation season is determined as 9.5 m2 in Taipei and 14.3 m2 in Kaohsiung. Furthermore, the influence level of the parameters is clarified that the area and shading performance of windows make a major influence on sensible cooling load; comparing to external shading, the window insulation performance is considerably less important. Overall, this study seeks the balance between energy use and thermal comfort then provide the efficient strategies at the initial design stage through the proposed criteria.

Solar Chimney (SC) can play a significant role in energy consumption reduction of ventilation applications. The primary purpose of this study is to ameliorate the performance of an inclined rooftop SC integrated with the Phase Change Material (PCM) and Photovoltaic (PV) module, called the SC-PCM-PV system. To this aim, the effects of using finned absorbers and composite PCMs on the performance of the SC-PCM-PV system are investigated for the first time. A 3D-CFD model is developed via the finite volume method to examine the impact of various design parameters, including fin number, fin thickness, PCM type, and PCM mass on natural ventilation duration, ventilation capacity, and power output. The results indicate that increasing the PCM mass decreases the ventilation capacity for the finless cases and does not significantly enhance ventilation duration. However, increasing the PCM mass enhances the ventilation capacity, ventilation duration, and power generation for the finned cases. Ventilation capacity and duration are improved by 7.7% and 17.6% when a finned absorber is used. It is revealed that copper-foam-based composite PCMs extend the ventilation duration of the SC-PCM-PV system. Furthermore, employing Sodium Acetate Trihydrate/Copper Foam (SAT/CF) as the PCM enhances ventilation capacity up to 19.8% compared to an SC combined with a PV module called the SC-PV system. Also, using paraffin/copper foam (Pa/CF) as the PCM provides the highest power output (5.54 kWh) and ventilation duration (22 h and 30 min), approximately 16% and 101 % more than those of the SC-PV system. Conducting a case study for Shanghai city, it is demonstrated that the SAT/CF and Pa/CF are decent candidates to provide natural ventilation for commercial (77.9% of ventilation capacity) and residential buildings (83.1% of ventilation capacity), respectively.

Dispersion and natural ventilation of hydrogen leaked at the floor center of a confined space are analytically and numerically studied in this contribution. Two symmetrical openings located atop two opposite walls and several sets of partition boards with varying heights, 0–1.0 m with 0.2 m increment, mounted under the ceiling were designed to examine their effects on ventilation efficiency. Without partition boards, a semi-analytical model combining a modified buoyancy ceiling jet theory and zone model was established to predict the key parameters at steady stage. The analytical predictions were compared with numerical results. 15 monitors were predesigned at an opening and the channels separated by the partition boards to collect the velocity and hydrogen concentration evolutions. The results show that the existence of the partition boards significantly promotes the ventilation efficiency by decreasing the hydrogen concentration in the confined space, constraining the flammable regime into a smaller volume, and increasing both the inflow and outflow velocities. Better ventilation efficiency is achieved by higher partition boards until a critical height after which no appreciable improvement can be gained. Applying the partition boards considerably shortens the developing stage of the dispersion process and intensifies the turbulence of outflow. Conclusions obtained in current work may benefit the natural ventilation system and building structure design for hydrogen safety in practical applications.

Building ventilation accounts for up to 30% of the heat loss in commercial buildings and 25% in industrial buildings. To effectively aid the reduction of energy consumption in the building sector, the development of demand-driven control systems for heating ventilation and air-conditioning (HVAC) is necessary. In countries with temperate climates such as the UK, many buildings depend on natural ventilation strategies such as openable windows, which are useful for reducing overheating prevalence during the summer. The manual opening and adjustment of windows by occupants, particularly during the heating season, can lead to substantial heat loss and consequent energy consumption. This could also result in the unnecessary or over ventilation of the space, or the fresh air is more than what is required to ensure adequate air quality. Furthermore, energy losses build up when windows are left open for extended periods. Hence, it is important to develop control strategies that can detect and recognise the period and amount of window opening in real-time and at the same time adjust the HVAC systems to minimise energy wastage and maintain indoor environment quality and thermal comfort. This paper presents a vision-based deep learning framework for the detection and recognition of manual window operation in buildings. A trained deep learning model is deployed into an artificial intelligence-powered camera. To assess the proposed strategy's capabilities, building energy simulation was used with various operation profiles of the opening of the windows based on various scenarios. Initial experimental tests were conducted within a university lecture room with a south-facing window. Deep learning influenced profile (DLIP) was generated via the framework, which uses real-time window detection and recognition data. The generated DLIP were compared with the actual observations, and the initial detection results showed that the method was capable of identifying windows that were opened and had an average accuracy of 97.29%. The results for the three scenarios showed that the proposed strategy could potentially be used to help adjust the HVAC setpoint or alert the occupants or building managers to prevent unnecessary heating demand. Further developments include enhancing the framework ability to detect multiple window opening types and sizes and the detection accuracy by optimising the model.

Solar energy is an environmentally friendly and renewable energy source which is utilized for electricity generation, domestic water heating and building ventilation. Solar chimney is a solar system that operates as a passive natural ventilation technique for diminishing building’s energy consumption and generating electricity from its power plant. However, the solar chimneys suffer from main drawback of non-operative conditions at night when there is no solar energy. Thermal energy storage using phase change materials (PCMs) is considered as an impressive solution for this limitation. Therefore, the present paper provides a literature survey on the incorporation of PCMs for performance improvement of solar chimneys in both buildings and power plant applications. The results obtained from the previous studies showed a great potential of PCM in enhancing the building’s thermal comfort, extending the ventilation time, improving the electricity generation of solar chimney power plants, and prolonging the generation period. Moreover, it is also observed that the thermal and geometric characteristics of PCMs have high influence on the overall chimney performance where the paraffins are the most used PCM materials in the available literature. Finally, economic, environmental and exergy analysis was recommended as future research directions beside the PCM’s optimal thickness, humidity control and super-cooling reduction.

To date, few studies have been conducted on the characteristics of flow and dispersion caused by indoor radiant floor heating integrated with natural ventilation. In this study, we employed reduced−scale numerical models validated by wind−tunnel experiments to investigate the influence of radiant floor heating integrated with natural ventilation on airflow, heat transfer, and pollutant dispersion within an isolated building. The Richardson number (Ri) was specified to characterize the interaction between the inflow inertia force and the buoyancy force caused by radiant floor heating. Several Ri cases from 0 to 26.65, coupled with cross− or single−sided ventilation, were considered. Model validation showed that the numerical model coupled with the RNG k-ε model was able to better predict the indoor buoyant flow and pollutant dispersion. The results showed that the similarity criterion of Ri equality should be first satisfied in order to study indoor mixed convection using the reduced−scale model, followed by Re−independence. For cross−ventilation, when Ri < 5.31, the incoming flow inertia force mainly dominates the indoor flow structure so that the ACH, indoor temperature, and pollutant distributions remain almost constant. When Ri > 5.31, the thermal buoyancy force becomes increasingly important, causing significant changes in indoor flow structures. However, for single−sided ventilation, when Ri > 5.31 and continues to increase, the buoyancy force mainly dominates the indoor flow structure, causing a significant increase in ACH, thus reducing the indoor average temperature and pollutant accumulation.

This paper aims to study the wind flow characteristics and to analyze the wind pressure distribution on the surfaces around an irregular octagonal plan shape building model. There is a central open space in plan to provide more surface area around the building for natural ventilation. Plan area of the building is 300 m2(excluding the open space) and height is 50 m. Steady state flow of wind with 5% turbulence (moderate turbulence) under atmospheric boundary layer has been taken in the study. Numerical simulation with standard k-e model using ANSYS (CFX) software has been used for the purpose. Flow characteristics has been studied in terms of flow separation, reattachment of flow, creation of wakes and vortices. The surface pressure generated around the model has been studied in terms of coefficient of pressure. The model is symmetrical about both the axes in plan. Hence, study for different wind angle of attacks from 0° to 90° @ 30° interval has been conducted. The flow characteristics and unusual or critical coefficient of pressure on surfaces of the model observed have been discussed. Doi: 10.28991/cej-2021-03091760 Full Text: PDF

Numerical analyses based on CFD steady RANS were conducted to investigate the effects of roof configuration on wind-induced natural ventilation for an isolated roofed building. Gable roof and saltbox roof building models were tested with 15˚, 25˚, 35˚ and 45˚ roof pitch in present study. The flow field information and flow characteristics were obtained from the contours and plots generated by CFD. In accordance to the increment of roof pitch, the turbulence kinetic energy and mean velocity ratio show vigorous response. The flow separated at the windward corner do not reattach onto the roof, thus induced higher velocity gradient and form a large vortex at the roof ridge. The vortices behind then building caused by the flow separation at the roof ridge extend along the mixing layer and spread up to the roof. The pressure differences mainly rely on the roof shapes. Greater pressure differences between the upstream, interior and downstream was observed in saltbox roof cases. This is due to the extended roof height which boosted the impinging effect caused by the incoming wind. Generally, the saltbox roof configuration exhibit better performance than gable roof in terms of the measured parameters.

PurposeThe purpose of this paper is to present the results of an experimental campaign conducted on a recently developed fire protection system (FPS), specifically designed for installation on continuous glass curtain walls systems typical of multi-story buildings.Design/methodology/approachThe authors will first present the theoretical derivation of the relevant parameters to characterize and predict the fire evolution and probability of flashover, according to existing codes and standards. Then, the results of two full-scale tests will be presented in terms of temperature fields, thermal gradients and position of the neutral plane.FindingsThe experimental evidence shows how the proposed system is able to dramatically reduce internal temperatures in the rooms interested by the fire, also allowing for safer evacuation procedures by increasing the height of the neutral plane.Originality/valueThe novel window frame element comprises an automatic doubly convergent aperture system that induces ventilation in the compartment by increasing internal convection in the rooms subject to the fire. This allows for an efficient dispersion of hot gases and fumes and a drastic improvement in safety for both the occupants and firefighting operators. The theoretical results are then compared to the experimental evidence to evaluate the performance of the proposed ventilation system in the context of existing standards and design procedures.

Window ventilation usually used in energy-efficient buildings as an effective natural ventilation system to provide an adequate opening for fresh air to flow into the interior space. It could help to reduce the indoor air temperature and limit the contaminants in buildings. This study aimed to visualise the airflow structure across a wooden louvred window panel using the smoke flow visualisation technique at different airflow speeds of 0.5, 1.0, 2.0, 3.0 and 5.0 m/s in a closed-loop wind tunnel. Two Sony 1920 × 1080i cameras captured the airflow structure, which took the side view, rear view, front view and back view images. The wooden louvred window panel promotes optimum outdoor airflow and facilitates continuous air exchange to replace the indoor air. Results showed that smoke filled the space quickly at the highest airflow speed of 5 m/s. This study used an inclination angle of 75° for the wooden louvred window panel to avoid rain splatter. Besides, wood material could be used as a facade shading device. Therefore, installing the wooden louvred window panels could enhance natural ventilation, ensure indoor thermal comfort and reduce indoor air contaminants.

In China, natural ventilation is a common way of improving indoor air quality (IAQ) in college classrooms. However, until now, the effects of both manual airing strategies and architectural factors on IAQ in classrooms have not been well explored. The present work aimed to investigate the effect of manual airing strategies, such as opening doors and opening exterior or interior windows, on the concentrations of both carbon dioxide (CO2) and fine particulate matter (PM2.5) in classrooms using field measurements. Through simulation, the effects of floor level, room orientation and the height of interior windows on CO2 concentration were also analysed. The results of this study revealed that (1) simultaneously opening doors and exterior windows or opening the doors alone could effectively reduce the indoor CO2 concentration, but the same effect could not be achieved by opening interior windows only; (2) the indoor PM2.5 concentration was primarily affected by the level of outdoor PM2.5, and it may exceed the recommended limit by 33% when the outdoor pollution level is high, even with closed doors and windows; and (3) in winter, both floor level and classroom orientation exerted a significant influence on the indoor CO2 concentration, but the height of interior windows had no effect.

Egypt faces many environmental problems. The increase in the urban population has led to an increase in the number of housing units, which changes the urban climate, or what is known as the phenomenon of the thermal urban thermal island, which is one of the biggest urban environmental problems facing the world in recent times and what followed from the steady consumption of energy, pollution and shortage resources and lack of quality of life. Hence the role of environmental sustainability and what it offers as solutions to some of these problems. Since the wind element is one of the important elements in improving the efficiency and quality of the built environment, reducing energy and thermal comfort. The main objective of the research is to focus on the importance of Computational Fluid Dynamics (CFD) simulation programs in improving the efficiency of urban settlement performance by studying natural ventilation for human health and thermal comfort, especially in the coastal communities that suffer from thermal comfort problems as an aid to planners And architects in urban planning and design to reach planning and design decisions and strategies in line with environmental sustainability standards. To achieve the main objective of the research, the importance of simulation programs was addressed to reach procedures and recommendations prepared to achieve sustainability and thermal comfort, the CFD model and related software treatments were applied and integrated as a small-scale wind assessment system through a number of stages, including program inputs from climatic elements and urban formation to be evaluated With the aim of guiding decision makers when designing and planning any urban assembly in order to achieve sustainable urban development.

Naturally ventilated double skin facade (NVDSF) absorbs solar radiation to introduce natural ventilation. It has been proved with significant importance in building energy-saving, and louvers on the NVDSF could be essential in real-life applications for the adjustment of uncomfortable flow. However, the impacts from this practical feature of adjustable louvers on the buoyancy-driven airflow are still not known. Motivated by this, this study addressed the influences of an operable outlet louver on the natural ventilation performance of an NVDSF, with louver angles of 30°–150° under various solar conditions (i.e., solar altitude angles within 10°–80° and direct incident solar radiation within 50–1,000 W/m2) for two types of glazing materials (i.e., regular and low-e glazing). A validated CFD model was used to solve the solar radiation and natural ventilation coupling problem between two semi-transparent facades. The results show that the outlet louvers’ influences are significant and should not be ignored in practice. Compared to the no-louver case, upward-opening louvers (louver angles within 30°–67.5° in this study) can promote the ventilation - the optimal louver angle at 45° can enhance the natural airflow by 10–14% for two types of glazings; whereas downward-opening louvers (112.5°–150°) will weaken the natural flow by 6–9% per increment of 10° in louver angles. Empirical models were also developed to quantify the impacts of the typical solar conditions on natural ventilation performance. The obtained power-form functions between the ventilation rates and solar factors (altitude angle and incident radiation) show similarities between NVDSFs and solar chimneys.

Natural ventilation is one of the important elements for creating a suitable healthy environment. It provides thermal comfort in buildings. However, the rising building densities and the high prices of land led to an increase in residential densities. Hence, high buildings appeared which obstruct natural ventilation and natural lighting and hinder the air movement around and inside the buildings there for, the need arises for studying problems stemming from opening in facades and the air movement outside and inside the buildings in order to reach natural ventilation for people’s comfortable inside the building. The present research discusses the idea of developing styles of architectural designees and exploiting modern techniques in design in order to increase effectiveness of natural ventilation through designing opening in facades in light of the phenomenon of climate change. In this research, the residential building was analyzed, ventilation was studied. Measurements were made. The research followed the analytical method for architectural elements to employ them, Such as the internal courtyards, The wind-catcher, places of openings and their measurements as well the building direction to achieve man’s thermal comfort inside the building.

Earth–air heat exchangers (EAHEs) and solar chimneys (SCs) can be used to improve indoor air quality and thermal comfort, and reduce the energy consumption of buildings. The ventilation and cooling performance of an SC integrated with an EAHE system (SCEAHE) on a typical sunny summer day is investigated herein, using a full-scale experimental test rig. The SC provides the driving force required to draw airflow through the EAHE pipe, and the air is cooled by the surrounding soil. The experimental results indicate that the buoyant driving force induced by the SC can drive the EAHE during the daytime. The maximum airflow rate achieved during the day was 252 m3/h. Furthermore, an airflow rate of 50–70 m3/h was achieved when the solar radiation intensity was low or zero due to the building thermal mass. Therefore, the combined effects of the building thermal mass and the SC provided 24 h of natural ventilation. The maximum reduction in the temperature of the outlet air compared to that of the inlet air was 12.5 °C. The maximum total cooling capacity, sensible cooling capacity, and latent cooling capacity of the EAHE were approximately 1398.0 W, 892.0 W, and 611.7 W, respectively.

In non-air-conditioned buildings, opening or closing of windows is one of the most common behaviours that occupants tend to carry out to restore their thermal comfort. As an alternative approach to...

The recent Covid-19 pandemic and its required hygiene protocols further revealed the importance of ventilation process in all buildings deal with human life. Solar Chimney Ventilator (SCV) is a type of renewable technology that is able to provide natural ventilation for the buildings. However, conventional SCV is not economical due to its low performance of ventilation. Thus, in the current study, an innovative tilted Solar Chimney Ventilator with Phase Change Material integrated with Photovoltaic technology (SCV-PV-PCM) is proposed and investigated under real unsteady transient weather condition (based on Hong Kong climate) via a validated three-dimensional numerical study. The characteristics of the SCV-PV-PCM is analyzed during the day (through different month i.e March, June, September, and December) and compared with conventional SCV-PV system. Based on the findings, the produced power and ventilation capacity of the SCV-PV-PCM is higher than those for the common SCV-PV system. Nonetheless, the system is not able to provide the appropriate ventilation power for the building through the winter due to lack of high ambient temperature and strong solar radiation. Moreover, it is concluded that using the SCV-PV-PCM in the building is most economically beneficial in the month of June by saving 2.88 $/month.

PurposeThe paper aims to investigate and evaluate the impacts of the voids combination as a passive design feature on wind-driven ventilation performance in high-rise residential building units. It proposes a series of building models and thereon indoor ventilation performance and outlining why and how these building models designed with architectural design features are important. This study aims to provide a comprehensive understanding of how natural ventilation as a passive cooling strategy in living units of high-rise residential buildings can be applied through improving the provision of the architectural design feature of voids configurations.Design/methodology/approachThe study was carried out through field measurements experiment and the computational fluid dynamics methods. A series of numerical simulations were carried out to calculate the indoor ventilation rate inside the case studies of the generated building models based on various variables such as horizontal voids type, size and wind directions.FindingsThe results indicate that the provision of a single-sided horizontal voids in building models can improve the indoor ventilation rate in units with cross ventilation mode up to 4 times, depending on wind direction and living unit location. The indoor ventilation performance in units located in models with single-sided horizontal voids is 17.54% higher than the units located in models without voids configuration. Furthermore, higher indoor ventilation performance was achieved in the case scenarios located at higher levels compared to the middle and lower levels in both horizontal voids types.Originality/valueThis study explores the application of voids combinations for natural ventilation performance, investigates the numerical simulation results and validates field measurements experiment data using CFD simulation.

The gas pressure generated during a coal and gas outburst is an important factor affecting the stability of mine ventilation systems. The gas released from an outburst flows and diffuses in the mine, leading to an uneven distribution of the air in the mine ventilation system and the formation of natural wind pressure. Because of the effect of the gas pressure, the mine ventilation system becomes disordered, leading to a counter flow in the roadway. This increases the complexity of the gas movement, extends the influence range of the gas, enlarges the disaster area in the mine, and exacerbates the destructiveness. In this study, the TF1M simulation program was applied to simulate a coal and gas outburst accident that occurred in the 1747 heading roadway of the Sizhuang Coal Mine, in a bid to reproduce the entire process of the diffusion flow of the counter current and outburst gas in the mine roadway. Moreover, the dynamic influence of the gas pressure on the entire ventilation network was analyzed. An experimental device was set up to test the relationship between the natural wind pressure and the height difference of the roadway and density of the gas flow, and the formation and mechanism of the natural wind pressure were explored. By analyzing the experimental and numerical results, the variation law of the air flow and the law of gas movement under the influence of gas pressure were summarized. The movement law and influencing factors of the gas during the mine outburst period were studied, the influence range of the gas was determined, the distribution law of the gas concentration after the outburst was obtained, and further expansion of the gas was prevented. This study has theoretical and practical significance in enhancing our understanding of the development process of mine gas disasters, which can help establish effective emergency response strategies and reasonably implement postdisaster relief measures.

El trabajo es una parte importante de la vida ya que permite la obtención de ingresos económicos. Asimismo, tener un trabajo satisfactorio es bueno para la salud física y mental de las personas. La Organización Mundial de la Salud en 1982 reconoció un síndrome el cual padecen los trabajadores, debido a las malas condiciones de la calidad del aire y del ambiente al interior de las construcciones. A este síndrome se le conoce como el Síndrome del Edificio Enfermo, el cual se utiliza para describir situaciones en las que los ocupantes experimentan problemas de salud físicos, mentales y molestias que parecen estar relacionadas con el tiempo que pasan en un edificio. Dicha situación afecta el desempeño laboral, la productividad y la salud del trabajador. El objetivo de la investigación es analizar el impacto que tiene la luz y ventilación natural en el ambiente de trabajo sobre el Síndrome del Edificio Enfermo y la productividad. La investigación tiene un enfoque cualitativo, con alcance exploratorio y diseño no experimental de corte transversal. Los resultados preliminares obtenidos evidencian que las malas condiciones físicas de trabajo afectan la salud física y psicológica del trabajador y lo exponen a condiciones de estrés laboral. Adicionalmente, es importante prestar atención a los factores internos y externos que impactan en los trabajadores, pues repercuten en su productividad y en su salud física y mental, tales son los casos de la luz y la ventilación natural, para evitar síntomas del Síndrome del Edificio Enfermo.

This work illustrates the results achieved by ongoing collaboration between the Uffizi Gallery and the University of Florence. This collaboration has focused on the New Uffizi Project and sought to evaluate the energy consumption of the HVAC systems of the Vasari Corridor by applying the typical tools and methods for the Building Energy Model (BEM) of existing buildings. In order to perform a dynamic simulation of the energy behavior and thermal comfort of the Corridor, the Building Energy Model was validated by comparing the hourly measured and simulated indoor temperature values and through the varying of natural ventilation and solar shading. Due to its building characteristics the control of the indoor thermo-hygrometric parameters is a critical issue. These aspects expose the Corridor to climatic variations which necessitate major energy consumption. In estimating energy consumption, three different scenarios of the use of the Corridor itself were referenced: one of which was its return to the original Medici use as a connection between Palazzo Pitti and Palazzo Vecchio through the Uffizi Galleries;the other two were the possible uses for temporary exhibitions of artwork which met the acceptable parameters of indoor air quality (thermal comfort and control of risk of SARS-CoV 2).

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.

Coronavirus disease (COVID-19) has infected many people worldwide. As the probability of being infected by the virus increases with an increase in the number of people gathered in an indoor space, methods for reducing its spread indoors are urgently required. In this study, a classroom with 25 students was considered as an indoor space, and an attempt was made to devise a method to reduce the concentration of the viruses generated indoors more effectively. Through numerical analysis, the age of air inside the classroom was compared and analyzed when both the air cleaner and natural ventilation were used. The age of air varied locally in the classroom depending on the position of the air cleaner, confirming its importance in effectively removing particles possibly containing viruses generated indoors. When the air cleaner flow rate was doubled, the age of air was almost halved, implying that the concentration of the particles including viruses generated indoors can be reduced efficiently by increasing the air cleaner flow rate. Natural ventilation performed by completely opening the windows and doors of the classroom reduced the age of air. It was observed that the operation of the air cleaner along with open windows and doors of the classroom reduced the concentration of the particles including viruses generated indoors more effectively. More specifically, when both natural ventilation and air cleaner were applied, the age of air decreased by almost 50% compared with the only air cleaner case and by about 22% compared with the only natural ventilation case. Copyright (c) 2021 American Association for Aerosol Research

To evaluate the separate impacts on human health and establish effective control strategies, it is crucial to estimate the contribution of outdoor infiltration and indoor emission to indoor PM2.5 in buildings. This study used an algorithm to automatically estimate the long-term time-resolved indoor PM2.5 of outdoor and indoor origin in real apartments with natural ventilation. The inputs for the algorithm were only the time-resolved indoor/outdoor PM2.5 concentrations and occupants' window actions, which were easily obtained from the low-cost sensors. This study first applied the algorithm in an apartment in Tianjin, China. The indoor/outdoor contribution to the gross indoor exposure and time-resolved infiltration factor were automatically estimated using the algorithm. The influence of outdoor PM2.5 data source and algorithm parameters on the estimated results was analyzed. The algorithm was then applied in four other apartments located in Chongqing, Shenyang, Xi'an, and Urumqi to further demonstrate its feasibility. The results provided indirect evidence, such as the plausible explanations for seasonal and spatial variation, to partially support the success of the algorithm used in real apartments. Through the analysis, this study also identified several further development directions to facilitate the practical applications of the algorithm, such as robust long-term outdoor PM2.5 monitoring using low-cost light-scattering sensors.

Green buildings and sustainable designs require architectural designers to go beyond the basic building codes to improve overall building energy performance, optimize building ventilation, minimize...

The thermal buoyancy generated by the difference in air density in a building can drive hot-pressed natural ventilation, which is an energy-efficient means of ventilation used to obtain higher air quality. Therefore, the effect of a single-point heat source with limited sides at different heights on stratified flow was studied in a naturally ventilated room in this paper. Based on the classical plume diffusion law of an independent point heat source and the mirroring principle, a calculation model of the thermal stratification height with a restricted source elevated to different levels was derived and validated. The quantitative effects of the heat source height from the floor, the effective opening area and other factors on the natural ventilation of hot pressure were analyzed. A threshold xT for the separation between a point source and a sidewall was defined to estimate whether the thermal plume was independent or restricted by a sidewall. And a method for calculating the threshold xT was obtained. This research can provide a reference basis for designing natural ventilation for buildings with a restricted heat source at different levels to achieve a desired indoor environment.

Energy efficient buildings are buildings that consume less energy while also maintaining or improving the comfort conditions for their occupants, compared to the normal building type. Such buildings result not only in less negative impact on the environment, but are economically sustainable and resilient. This study investigated the extent to which building professional firms in Abuja, Nigeria are aware and implement the different energy efficiency design strategies available for deployment in office buildings, in order to ascertain the current level of knowledge and implementation of the strategies within the building industry in the study area. A structured questionnaire was used to gather data from 80 professionals drawn from architectural and engineering firms involved in the design of office buildings in the study area. The data were analysed by descriptive statistics and the results indicate that both the awareness and implementation levels of energy efficiency design strategies by the firms are high. Whereas most (78%) of the respondents are aware of the various energy efficiency design strategies employed in office building designs, few (22%) of them have little or no knowledge of the strategies investigated. On the implementation level, majority (69%) of the participants recorded a high rate, while few (31%) recorded a low rate. The study also found that the strategies the firms are mostly aware of are site planning, natural ventilation and building orientation. Whereas, the three most adopted strategies among the strategies investigated are: building plan and space organisation; site planning and building orientation. Among the recommendations of the study is that relevant stakeholders of the building industry in the country, should provide platforms from time to time for promoting the benefits of energy efficiency design strategies in the country, in order to maintain the high level of understanding and deployment of the strategies by the building professionals that currently exist in the study area. This is envisaged to ultimately lead to curtailing the adverse effects of global warming on the environment in the long run.

With the rapid and sudden spread of the emerging Coved-19 virus, avoiding gatherings and close contact with others, and keeping billions of people around the world at home is imperative to curb the rapid spread of the mutated virus. As that situation continues without the ability to determine the expected time for life to return to pre-Covid 19, psychological pressures on human beings are increasing and many suffer from an inability to adapt to current circumstances; In this period of the corona virus outbreak, the call for social spacing, work and learning from home, the role of the residential environment is more important than ever. The house is no longer only a shelter, but must also be an educational and office environment, a place of entertainment and a place of rest and relaxation. Therefore, the multiplicity of functions and roles within the single dwelling has become a new challenge for interior architects. That pandemic has led us to reassess the role of housing and how to prepare for the future. Hence, the research tries to present some strategies and methods to create the best living environment within the residential space. Background and problem: The twenty-first century witnessed a number of epidemics, including the recent corona epidemic, which led to the imposition of a state of isolation, social divergence and isolation within residential spaces, which has become a place for all living activities, work and distance learning. The forced isolation of millions of the world's population has revealed that residential spaces are repellent spaces that lack many elements of life, which would require a change in the concept of designing residential space in the future after the changes imposed by the Corona crisis. Significance: Corona pandemic imposed a reality that requires focusing on the concept of work and learning from home, as a basic need that will continue for a long time even after the end of the Corona crisis. Here must be a review of the design of residential spaces to be able to face those changes, which will become an urgent necessity in the coming days, which will force the designer of interior architecture to embark on innovative design ideas and solutions for those spaces by trying to answer the following questions: How will the concept of residential space change during & after the pandemic? How can the privacy required for learning & working from home be achieved and separated from living spaces? How can the quality of the internal environment and health considerations be achieved to cope with the spread of diseases? How can the negative effects of spending all the time in the dwelling on productivity and mental health be avoided? Objectives: The research aims to study the human considerations and new needs of residential spaces in light of the changes imposed by the Corona crisis and to find the integration of the elements of design and how to employ them correctly. Study appropriate solutions for the planning of residential spaces to accommodate different functions taking into account the health considerations of those spaces and the use of appropriate materials and try to avoid the negatives imposed by the Corona crisis and its impact on the future design of residential spaces. Methodology: Research methodology follows the descriptive and analytical approach by studying the impact of the Corona pandemic on changing the design concept of residential spaces, and a study of the role of new technology and solutions and design alternatives of new materials or new treatments for natural and artificial materials or new technologies and advanced systems in improving the quality of the internal environment of residential space. Conclusions: In this period of the world's outbreak of coronavirus, the call for social spacing, work and learning from home, the role of the residential environment is more important than ever. The multiplicity of functions and roles within the single dwelling has become a new challenge for interior architects, as the need to provide flexibility in the planning of interior spaces and the provision of privacy factor away from noise. The importance of the role of digital technology in communication, work management and distance learning, which affects human behavior, spatial and design needs, productivity rates and economic, environmental and human gains. For scientific research in the field of nanomaterial an important role in the development and development of self-cleaning paints and materials and resistant to bacteria, microbes and dirt, which contribute to reducing the spread of bitterness by touching the internal surfaces. The need to take into account the quality of the internal environment of the residential space from increasing the flow of natural ventilation by increasing mechanical or natural ventilation in the interior space, the use of air quality sensors and tracking the relative humidity rates in the dwelling. The importance of moving activity through the allocation of spaces for activities and sports home either by sports devices or even providing a free space of furniture for exercise and the use of changeable furniture at its height, which gives freedom of movement in case of standing or sitting beside replacing seats with sports equipment to motivate the user to move from time to time. The importance of addressing residential interior spaces in a way that gives users of these spaces openness to nature, and the employment of plant elements, natural materials and colors derived from nature, which increases the sense of warmth and intimacy of the void and reduce the sense of siege imposed by quarantine. Considering the study of how to employ natural light within the residential space, where natural lighting plays an important role in providing psychological comfort to users of the internal space through the user's visual association with the vast external environment, also has an important role in not losing the human connection with time, cognition and the outside world, which may increase during periods of quarantine during which the user is forced to stay in the dwelling for long periods. Natural lighting is also a source of UV radiation, which helps build the immune system by increasing the production of white blood cells, as well as its role in weakening the spread of germs and viruses as well as its role in increasing energy and productivity rates.

Since the coronavirus disease 2019 (COVID‐19) outbreak, the nosocomial infection rate worldwide has been reported high. It is urgent to figure out an affordable way to monitor and alarm nosocomial infection. Carbon dioxide (CO2) concentration can reflect the ventilation performance and crowdedness, so CO2 sensors were placed in Beijing Tsinghua Changgung Hospital's fever clinic and emergency department where the nosocomial infection risk was high. Patients’ medical records were extracted to figure out their timelines and whereabouts. Based on these, site‐specific CO2 concentration thresholds were calculated by the dilution equation and sites’ risk ratios were determined to evaluate ventilation performance. CO2 concentration successfully revealed that the expiratory tracer was poorly diluted in the mechanically ventilated inner spaces, compared to naturally ventilated outer spaces, among all of the monitoring sites that COVID‐19 patients visited. Sufficient ventilation, personal protection, and disinfection measures led to no nosocomial infection in this hospital. The actual outdoor airflow rate per person (Q c) during the COVID‐19 patients’ presence was estimated for reference using equilibrium analysis. During the stay of single COVID‐19 patient wearing a mask, the minimum Q c value was 15–18 L/(s·person). When the patient was given throat swab sampling, the minimum Q c value was 21 L/(s·person). The Q c value reached 36–42 L/(s·person) thanks to window‐inducted natural ventilation, when two COVID‐19 patients wearing masks shared the same space with other patients or healthcare workers. The CO2 concentration monitoring system proved to be effective in assessing nosocomial infection risk by reflecting real‐time dilution of patients’ exhalation.

Most of the window use models developed for building energy simulations include physical environmental variables as drivers. Even though it is a common approach to include these variables, the validity of this approach can be questioned based on observations in the literature regarding the consistency and seasonality of the relationship between these variables and the window use. Additionally, it was questioned whether this approach could capture the inter-occupant diversity. To assess the extent of the uncertainties, modelling methods from the literature were applied to a case study. The results revealed that a large share of the variance in window use can be attributed to the season and the household-ID. This indicates that the window use varied across the year but was stable within one season, and that these behaviours differed significantly between households. Thus occupants interacted with windows according to seasonal habits, more so then according to momentaneous environmental conditions.

The fight against climate change is a significant challenge, resulting mainly from the linear and extensive exploitation of natural resources, particularly fossil fuels. Its impacts are now recognized. The current climate models are neither sustainable nor ecological in economic and social terms, especially as we live in a century marked by galloping demography and urbanization. Researchers worldwide have paid great attention to passive solar design strategies such as double skin or Second Skin Façade. From this point, the present work aims to contribute to a better understanding of the feasibility of using a passive façade as a useful technology for natural ventilation to achieve potential energy savings and improve thermal comfort and indoor air quality. For this purpose, a parametric study was conducted for a room with four different southern facade configurations in six Moroccan climatic zones; the difference between each lies in the vent's position in the entrance and exit. This process was done by using COMSOL Multiphysics software. Velocity and volume flow rate fields were analyzed. The proposed configurations provided an average volume flow rate between 200 m3/h and 400 m3/h for a surface of 1 m2 of southern façade with an air vent area of 0.1mx0.2m.

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.

A hybrid ventilation system combining both natural and mechanical ventilation has proven very promising in moderating indoor climate, based on its ability to ensure indoor air quality with low energy consumption. The system maintains indoor thermal comfort conditions by switching to mechanical mode whenever natural ventilation is not possible. However, the application of such a system in severe arid climates is still very limited and challenging, and almost half the urban peak load for energy demand is used to supply cooling and air-conditioning in summer. This paper assessed the application of the hybrid ventilation mode for an educational building in a hot, arid climate, with the aim of reducing the building’s energy consumption without compromising the occupants’ thermal comfort. A dynamic simulation was conducted using Integrated Environmental Simulation in a Virtual Environment building energy software, and the outcomes were validated against actual consumption data over one year. The results were then evaluated for indoor thermal comfort and energy reduction and showed the potential of the hybrid system to provide energy savings of 23% across the year. Better energy performance was achieved during the cooler seasons (33.5%) compared to hot (17.1%). When photovoltaic systems were incorporated, by examining different inclination angles and locations for energy savings and carbon emissions (CO2) reductions, the outcomes proved that photovoltaic south and a 25° tilt angle recorded the maximum energy and minimum CO2 emissions annually. This integration of hybrid ventilation and photovoltaics reduced the building’s energy consumption from 106.1 MWh to 36.6 MWh, saving almost 85% in total annual energy and cut down the carbon emissions from 55,227 kgCO2 to 6390 kgCO2.

A ventilação natural é uma estratégia eficiente para o condicionamento térmico passivo de edificações. No entanto, muitas vezes esse recurso é subutilizado em habitações de interesse social (HIS), caracterizadas por projetos padrões sem considerar as características climáticas da região. Além disso, essas habitações são implantadas em lotes pequenos com a presença de muros para segurança e privacidade dos moradores, impactando significativamente no aproveitamento dos ventos externos. O artigo aborda como os projetos das HIS são muito subutilizados do ponto de visto da ventilação natural, visto que o uso de estratégias simples e de baixo custo ajudam no conforto térmico além de manter a segurança e a privacidade dos moradores, tais como o uso de muros permeáveis.

Ceiling fans are the most common equipment in any household with electricity to induce a higher air movement since the potential of natural ventilation is limited. However, the higher airflow region is generally limited to the zone below the fan. The non-uniform distribution of airflow is also affected by the furniture layout and airflow from window openings. This study attempts to evaluate the effect of the different window-opening patterns on the airflow inside naturally ventilated bedrooms, having a ceiling fan for air movement with numerical simulations and on-site measurements. The airflow pattern created by a ceiling fan in a room with furniture is modelled and simulated with ANSYS Fluent 2019 R3. The results were validated with on-site measurements and compared with the literature. The air velocity was measured in bedrooms of three different sizes. It was observed that the opening of windows created a better distribution of air irrespective of room size. The non-uniformity of the air velocity is reduced from 76% to 39% with the opening of windows in the larger-sized room. The reduction in non-uniformity is influenced by the location of windows also. The practice of opening windows along with the induced air movement by ceiling fans results in a better distribution of air in the space. Practical application: People tend to depend mainly on ceiling fans even if windows are open in naturally ventilated rooms. A study of patterns of non-uniform distribution of airflow can help designers to improve comfort conditions by specifying the number and location of fans and windows while designing room furniture layout. This aids the building services engineers to provide thermal comfort without always depending on alternative active ventilation strategies.

This study investigates the effect of opening position on the indoor airflow of a natural ventilated isolated building model. Furthermore, the opening configuration which generate the highest ventilation is to be determined. Seven different opening configurations were considered by varying the opening position on the windward and leeward walls which include three cases of aligned openings and four non-aligned openings. Models with different opening position were simulated using Computational Fluid Dynamics (CFD) with 3D RANS turbulence model Shear Stress Transport (SST) k- ω. Simulation result indicates the indoor air velocity as well as pressure distribution highly depends on both inlet and outlet opening positioning. Different opening configuration influences the recirculation zone generated within the building model. Comparison shows openings located near the roof generate 6.52% higher ventilation rate compared to openings located near the ground. The study concludes that opening position holds a crucial role in affecting internal airflow pattern, air recirculation and ventilation rate for a natural cross ventilated building.

Student performance in classrooms is related to the indoor environmental quality. High air change rates are necessary to secure an acceptable level of indoor air quality and provide fresh air, which require large amounts of energy and technical installations. Mostly, mechanically supplied air is partially mixed with the return air. In warm climates, the capacity for natural ventilation is not fully exploited in modern buildings. During periods of acceptable outdoor temperatures, buildings need to adapt and employ available free renewable resources, such as wind. In this context, the building form, orientation, and envelope openings are crucial to enable an increased air change rate, user satisfaction, and energy savings. Owing to the difficulty of providing cross-ventilation in buildings with double-loaded corridors, single-sided ventilation is the most common approach. This study investigates the methods to improve the wind-driven air exchange of classrooms in warm climates, where naturally ventilated corridors help increase air movement. This study examines the potential of a set of alternatives within the context of a generic model regarding the pressure distribution, thermal sensation, air velocity, and air change rate. The study suggests that no single opening scenario can be applied to all façades at any time. Each façade requires special treatment. Decisions on natural ventilation need to be made during the early design stages for each façade. It was found that with the aid of low-tech modifications, remarkable increases in air change rates, in some cases up to 14.5 times that of the typical single-sided ventilation case, could be achieved.