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A combined windcatcher and light pipe (SunCatcher) was installed in the seminar room at the University of Reading, UK. Monitoring of indoor environment in real weather conditions was conducted to evaluate the application of windcatchers for natural ventilation. In addition, a subjective occupancy survey was undertaken. External weather conditions and internal indoor air quality indicators were recorded. The “tracer‐gas decay” method using SF₆ was used to establish air change rate for various conditions. The results indicated that the ventilation rate achieved through the windcatcher depends on the difference between internal and external air temperatures, and on wind speed and direction, in agreement with other published work in the area. The indoor air quality parameters were found to be within acceptable levels when the windcatcher was in operation. The measured air change rate was between 1.5ac/h and 6.8ac/h. Occupants’ questionnaires showed 75 per cent satisfaction with the internal conditions and welcomed the installation of the systems in UK buildings.

The use of natural ventilation by large openings to maintain thermal comfort conditions in the premises is a concept that is perfectly integrated into the traditional architecture of countries in the Mediterranean region or in tropical climates. In a temperate climate where the architecture is not usually designed to respond to the use of natural ventilation is seasonal and is done at the initiative of the occupants by making changes in the design of their doors. The European interest in natural ventilation, as a passive building air-conditioning technology, is increasing and has been the subject of a research program commissioned by the European Community. In this work, the authors consider a part of a housing compound as a refreshing floor. This floor is maintained at a constant cold temperature, the one vertical wall at hot temperature and other surfaces are adiabatic. Various scenarios are considered for this work. Mixed convection for different boundary conditions and different configurations is carried out. In addition, an airflow is injected through a window and extracted on the opposite window. Classical conclusion and transitional value on Richardson number have been completed by the new thermal configuration with nonsymmetric thermal conditions. The complex 3D flow structure is more obvious when one of the two flows (ventilation or natural convection) dominates. However, the induced heat transfer is less sensitive to the added ventilation. In this study, the authors consider a part of a housing compound as a refreshing floor. This floor is maintained at a constant cold temperature, the one vertical wall at hot temperature and other surfaces are adiabatic.

This is a qualitative preliminary study of a 2D–3D flow. The authors examine the competition between the natural convective flow and the added airflow on the flow structure and indoor air quality. The numerical model shows a good agreement with that obtained by researchers analytically and experimentally. To deal with turbulence, the RNG k-ε model has been adopted in this study.

The transfer is more sensitive between the 2D and 3D cases for the present analyzed case.

The study of ventilation efficiency has shown the competition between the big and small structures and the induced discomfort.

A comprehensive investigation on the outlet air position effects on the thermal comfort and air quality has been achieved. In addition, airflow and temperature distributions in ventilated cavities filled with an air-CO₂ mixture with mixed convection are predicted. The airflow enters from the cavity through an opening in the lower side of the left vertical wall and exits through the opening in one wall of the cavity. This paper aims to investigate the outlet location effect, four different placement configurations of output ports are considered. Three of them are placed on the upper side and the fourth on top of the opposite side of the inlet opening. A uniform heat and CO₂ contaminant source are applied on the left vertical wall, while the remaining walls are impermeable and adiabatic to heat and solute. The cooling efficiency inside the enclosure and the average fluid temperature are computed for different Reynolds and Rayleigh numbers to find the most suitable fluid outlet position that ensures indoor comfortable conditions while effectively removing heat and the contaminant. This is demonstrated by three relevant indices, namely, the effectiveness for heat removal, the contaminant removal and the index of indoor air quality.

The simulations were performed via the finite-volume scSTREAM CFD solver V11. Three different values of CO₂ amount are considered, namely, 10³, 2 × 10³ and 3 × 10³ ppm, the Reynolds number being in the range 100 ≤ Re ≤ 800.

Based on the findings obtained, it is the configuration whose air outlet is placed near the heat source and the contaminant, which provides a better air distribution and a ventilation efficiency compared to the others ventilation strategies.

The studies on heat and mass transfers by natural and forced convection in ventilated cavities remain a fruitful research topic. Thereby, such a study deals with different ventilation strategies through cavities containing an air-CO₂ mixture subjected to a mixed regime. In particular, the air inlet velocity and contaminant sources’ effects on thermal comfort and air quality have been investigated.

The purpose of this paper is to describe the use of computational fluid dynamics (CFD) to simulate indoor radon distribution and ventilation effects. This technique was used to predict and visualize radon content and indoor air quality in a one‐family detached house in Stockholm. The effects of intake fans, exhaust fans and doors on radon concentration were investigated.

In this study a mechanically balanced ventilation system and a continuous radon monitor (CRM) were used to measure the indoor ventilation rate and radon levels. In a numerical approach, the FLUENT CFD package was used to simulate radon entry into the building and ventilation effects.

Results of the numerical study indicated that indoor pressure created by ventilation systems and infiltration through doors or windows have significant effects on indoor radon content. The location of vents was found to affect the indoor radon level and distribution.

It may be possible to improve any discrepancies found in this article by using a more refined representation of grids and certain boundary conditions, such as pressure and temperature differences between inside and outside and by considering some real situations in residential buildings and external situations.

From the viewpoints of indoor air quality (IAQ) and energy savings, ventilation has two opposing functions; on the positive side it enhances IAQ and the establishment of thermal comfort, and on the negative side it increases energy consumption. This paper describes the search for a solution to cope with this contradiction.

The contemporary urban fabrics in hot climate regions have overextended urban spaces that face problems of high heat stress due to intense solar radiation and air temperature and that cause the pedestrians to abandon the urban spaces due to thermal discomfort. This work introduced the shading effects as one of the prime factors that contribute to restore thermal comfort and attract pedestrian activities. The purpose of this paper is to identify the proportional limits of the urban space to maintain feasible shades for pedestrian activities.

The urban space abstracted into a floor surrounded by four walls was then classified into four typologies. The assessment tool was developed to calculate the shading efficiency at the floor level of urban space. The width and the length of the floor equally was expanded in the range (0.5/0.5 to 4.0/4.0). The average shading efficiency of the expanded typologies was calculated along three intervals (Morning, midday and afternoon). The results were then analyzed, and critical guidelines were established that could be utilized in the design of the futuristic urban space and provide amendments to the existing urban space.

The paper concluded that the performance of urban spaces was not due to the accumulative performances of all walls but rather due to the combination specific effective walls in response to the interactive variations shading patterns concerning daily pedestrian activities. Any large shallow urban space could be segmented into multiples of the recommended typologies by a vertical landscape.

It is the first study that identified the expansion limit of the urban space that maintains feasible shades for the pedestrian. A further value of this study is establishing guidelines to the urban designers for the effective configurations of the urban space in terms of shading. These guidelines could be utilized in the design of the futuristic urban space and provide amendments to the existing urban space.

The ventilation and air-conditioning systems consume the highest energy in the building sector. The proper ventilation in residential buildings through the passive solar systems can substantially reduce the energy consumption in building sector. The paper aims to identify the application of wind shaft as a solar chimney, a passive ventilation system and evaluated the performance of the system.

The paper investigated the performance of the solar chimney with size, absorber area 9.76 m2 and height 4.57 m, based on experimental data recorded in the city, Kota (25°10N, 75°52E), India. Solar data were recorded using the state of the art weather station situated very closer to the residence. The air velocity and temperatures in the chimney and in the building are recorded in data logger. A simple mathematical model was used for the evaluation of the air change per hour (ACH) in the residential building.

From the analysis of weather data, it was found that the ambient temperature varies linearly with the solar irradiance. Air change rate of 5.7-7.7 can be achieved from this solar chimney, in peak summer season which is appropriate and meets the ventilation requirement as per BIS (Handbook of Functional Requirements of Buildings – 1987).

The air temperature increases from bottom to top in the solar chimney. The solar irradiance dictates the chimney air temperature, and both are in step with each other. It shows that the solar chimney is working in tune with the solar radiation availability. In peak summer, it provides sufficient ACH to the tune of 3-6. Resulting wind shaft can act effectively as a solar chimney. It is a feasible solution for the ventilation needs and it improves the looks of any residential building.

To provide the performance comparison between the conventional mixing ventilation (MV) and the displacement ventilation (DV) with and without cooling ceiling, which can be helpful to design.

The commercial CFD software FLUENT with RNG k‐ε turbulent model was used. The CFD method was validated via comparing with the available experimental data.

It was found that if properly designed, the DV system can supply better indoor air quality in the occupied zone, including better distribution in temperature field, higher ventilation efficiency, lower contaminant field and more thermal comfort compared with the MV system, because of the stratification effect of DV. And the locations of return air outlets have a great effect on the performance of the ventilation system. It was also found that the DV systems can be used to remove air contaminations more efficiently, but the temperature difference in the occupied zone in the DV system is higher than that in the MV system, especially if the heat load is higher. This problem may be solved if the cooled ceiling is combined with the DV, because the vertical temperature in the occupied zone will be reduced and more thermal comfort can be achieved.

More detailed computation should be performed on the thermal radiation between different surfaces in the room.

A very useful source of information for thermal designing of air condition.

This paper provides the performance comparison between the conventional MV and the DV with and without cooling ceiling, based on flow and temperature distribution.

To evaluate the control strategy for a hybrid natural ventilation wind catchers and air‐conditioning system and to assess the contribution of wind catchers to indoor air environments and energy savings if any.

Most of the modeling techniques for assessing wind catchers performance are theoretical. Post‐occupancy evaluation studies of buildings will provide an insight into the operation of these building components and help to inform facilities managers. A case study for POE was presented in this paper.

The monitoring of the summer and winter month operations showed that the indoor air quality parameters were kept within the design target range. The design control strategy failed to record data regarding the operation, opening time and position of wind catchers system. Though the implemented control strategy was working effectively in monitoring the operation of mechanical ventilation systems, i.e. AHU, did not integrate the wind catchers with the mechanical ventilation system.

Owing to short‐falls in the control strategy implemented in this project, it was found difficult to quantify and verify the contribution of the wind catchers to the internal conditions and, hence, energy savings.

Controlling the operation of the wind catchers via the AHU will lead to isolation of the wind catchers in the event of malfunctioning of the AHU. Wind catchers will contribute to the ventilation of space, particularly in the summer months.

This paper demonstrates the value of POE as indispensable tool for FM professionals. It further provides insight into the application of natural ventilation systems in building for healthier indoor environments at lower energy cost. The design of the control strategy for natural ventilation and air‐conditioning should be considered at the design stage involving the FM personnel.

Mechanical ventilation with heat recovery (MVHR) is increasingly being promoted in the UK as a means of reducing the CO₂ emissions from dwellings, and installers report growing activity in the retrofit market. However, the airtightness of a dwelling is a crucially important factor governing the achievement of CO₂ reductions, and the purpose of this paper is to understand the technical implications of airtightness levels in an experimental dwelling, purpose built to typical 1930s standards, at the same time as gaining the users’ perspectives on airtightness and ventilation in their homes.

In‐depth interviews were carried out with 20 households to collect information on their retrofit and improvement strategies, attitudes to energy saving and their living practices as they impinge on ventilation. The experimental house was sealed in a series of interventions, leading to successive reductions in the air permeability as measured by a 50 Pa pressurisation test. The behaviour of a whole‐house MVHR system installed in the experimental house, was simulated using IES Virtual Environment, using a range of air permeability values corresponding to those achieved in the retrofit upgrading process.

In the house considered, air permeability must be reduced below 5 m³/m²h for MVHR to make an overall energy and CO₂ saving. However, to achieve this required a level of disruption that, on the basis of the views expressed, would be unlikely to be tolerated by owners of solid wall dwellings.

The paper is the first to combine results from a user‐centred approach to exploring the existing practices of householders with a simulation of the energy and CO₂ performance at different levels of airtightness of an experimental house in which MVHR has been installed.

The improvement in the quality of life together with thermal comfort, air quality, health, workplace security and energy conservation measures justify the integral education of environmental (outdoor and/or indoor) phenomena. Environmental education, through the appropriate tool, can play an important and vital role in this domain. Computational fluid dynamics (CFD) is the analysis of systems involving fluid flow, heat transfer and associated phenomena such as distribution of pollutants by means of computer‐based simulation. This technique, allowing the simulation and the visualization of environmental problems, represents a powerful tool to motivate, guide and educate on the environment. The main objective of this paper is to introduce this new advanced active tool in environmental education, directed to indoor‐environment quality, that permits the prediction and visualization of air movement, air temperature and air contaminant (such as tobacco smoke) distribution in rooms. With suitable mathematical models and boundary conditions, a computational code has been developed to predict and visualize these phenomena. In order to demonstrate its applicability, the simulation of air contamination distribution in an office room with a smoker was performed.