At the root of all living beings is our breath — without it, we are not alive.
A putative perception of the future, the mechanism for the urban breathing system or ventilation is introduced to beat the thoughts on the hermetically sealed buildings. The field of architecture has been searching for the ultimate solution of this sealed issue because it’s a major problem, but as there are already air conditionings systems are using but their focus is more the physical skin of the building instead of the substance that is Air. Achieving healthy indoor air quality is all-round problem which can only be alight by a thorough and integrative approach to the design, construction and operation of buildings. Ventilation is identified as the most effective means to remove soaring air from buildings, considering it an efficient airflow rate, filtration and airflow patterns. Studying the importance of indoor environments specifically indoor air quality and finding the conclusive solutions through architectural education, available equipment and resources.
On average, people spend most of the time almost 90% indoors like offices, school buildings or homes since the majority of the people’s daily activities take place inside. So the impact of the inside environment affect the health, productivity and comfort of the people.
Research has shown that the indoor air pollution can actually have more damaging effects on the health than the pollution in the air outside. So good ventilation is essential for a healthy and efficient building. It’s very important to work on architectural design by the examining air, and the natural ventilation of the buildings, as buildings are the living spaces where we spend most of our time and breathe in. When we think of designing complex forms of cities, how particular shape might make a difference. Rethinking how we built the structures we live and work in and examine the current scenario with more applicable and healthy solutions.
‘Our cities of smooth stone and steel may become more like floating forests ‘ with buildings that can think and breathe and cool themselves’, says architect Philip Beesley.
So that saying of Philip, is the basic inspiration of my idea that how I perceive architecture to help in making the buildings environmentally responsive and friendly living.
For architects, the environmental movement highlights some important questions. Is it possible for a profession involved in creating the built environment to help diminish or reverse the damage done to the natural environment? If buildings are substantially a means of adapting nature to fulfill human needs, is it even possible to make buildings that are environmentally friendly? The answers to these questions depend on the understanding of how buildings reorient nature in order to make spaces suitable for human accommodation. To help understand how buildings modify nature, the idea of a building as an environmental filter, various aspects of the external environment (air) to pass through to interior space.
1.1Statement of purpose:
The awareness of the importance of living place and indoor air quality has increased for both health and comfort. The growing requirements for indoor environments in terms of ventilation in homes, offices, hospitals, institutions and industrial facilities have rapidly increased overall energy demands because there are many mechanical systems that are working to control the inside air quality. So there is the need to work towards improving indoor air quality which produces natural ventilation and cooling system so that energy consumption is minimized and the building design could attain better approach.
1.2Aims and Objectives:
The goal of the research presented in the dissertation is to develop a better understanding of
‘ Importance of natural air inside the building to make the indoor environment breathable and healthy for the occupants.
‘ The important parameters in the performance of ventilation systems, either natural or mechanical.
‘ To identify the issues and problems in making the indoor environment healthy in urban areas.
‘ To provide a comfortable indoor environment by analyzing the natural ventilation possibilities incorporated with mechanical system to minimize the energy consumption.
1.3 Research Methodology:
I collect the surveys and questionnaires that help me or directed me toward a conclusion, also take the interviews from households, office workers and architects that help me to understand better and give me an approach towards this major problem that is faced in daily life.
It is a meaning full exercise that helps me to investigate these issues and make me think for the innovative solutions and upgrade our ventilation systems through architectural design. And it is difficult to conduct the pictures of indoor that are lying in the category of effected spaces, because people don’t feel it save or are not open enough to shot the snaps of their homes.
Buildings are not normally perceive as a form of technology may be because buildings last a long time, together making up the museum for living beings known as a city, where antiquity from past ages are still in use side by side recent works. So the standards are set that are used to judge and influence new designs that how the environment within the buildings is created, and how that can be done in ways that provide greater connection with and respect for the natural environment.
The concept is concerning architecture synthesis and architectural design with respect to the natural environment. So it’s basically based on passive designing that how important the air circulation is and the natural air ventilation is in the design and making the building breathable. The concept of ‘Environmental responsive architecture’ is basically to enable the spaces to breathe.
For example the work of Sir Norman Foster; is persistent in bringing forth architectural solutions to problems that other architects can only theorize. His main aim is to intensify and enlarge the human experience with architectural solutions that are both inventive and functional. Sir Foster’s first green building came long before such distinction were in any sort of mod, and even by today’s standards, the Willis Faber and Dumas Headquarters building is a classic example of environmentally informed and respectful design. Requiring the scale of a small office tower, but needed to be in keeping with its surroundings, the building is a simple three-story that fulfills its dimensional requirements with a blot-like shape that stand by to the surrounding Medieval street plan – ‘flowing to the edges of the site, like a pancake in a pan’. Ambitious to undermine the tenets of modernism, Foster created a building that was shaped by its surroundings and purposefully at difference with the lessening tendency for a historical architecture.
Awarded Grade I listed status in 1991 for its ability, it was the newest building ever to be given this honor, and has since been resistant to future changes.
Figure 1.1 Willis Faber and Dumas Headquarters building
Technology and Environment
The idea of the building as an environmental filter was contemplate nearly 60 years ago by James Marston Fitch, in his book American Building. ‘The central function of Architecture’, wrote Fitch, is ‘to lighten the very stress of life’. By creating shelter, buildings reduce the need to continually seek immunity from the natural environment and, instead, free up time and energy
to undertake the various social and cultural activities that designate human attainment. These activities, according to Fitch, are the ‘essence of human experience’.
Nature provides the environment for all living beings including humans, and allows them to complete and survive. Most would agree that, for healthier and happier lives, people should know more about nature and the natural environment. When it comes to nature, the natural elements like light, air and natural materials are the basic major requirement that will help in building up a better environment. So it’s obvious that good air quality plays a major role in making building user friendly. The aim is to show that environmental considerations are among the most elemental of all design conclusions, affecting the size, shape and orientation of any building, the materials used for construction, the interior layout, and the location of windows and doors that link inside and outside space.
Writings about the first house by architects from Marcus Vitruvius to Le Corbusier reflect the combination of available material and technological ability; trees felled from a forest clearing, for example, could be used to make fire or to make shelter or both together.
The earth is encased with two fluids: water in the oceans and air in the surroundings. While old people may have lived anywhere, today humans suppose to live where earth, air and water meet; at the edges of rivers and lakes and oceans, under a layer of air several kilometers thick. The air provides an ideal mix of gases at just the right pressure to sustain human life. Air is a medium from which we get the oxygen needed for existence and into which we extract the oxygen in the form of carbon dioxide. People can breathe most easily within usual range of atmospheric pressure at or near sea level- around 100 kilopascals. At higher altitudes, pressure decreases, making difficult and possibly resulting in altitude. At lower altitudes-underwater-breathing is possible only with the help of scuba tanks.
In average temperature on the surface of the earth is about 15 ”C, thanks to an atmosphere that helps to retain the heat arriving from the sun. Without the atmosphere, the average temperature would be much lower, around -18 ”C, making it not just hard to breathe, but too cold to support most forms of life.
Figure 2.1 Air Temperature
2.2 Cooling Air:
Another importance of experimental science in the 18th century was the greater understanding of the physical processes associated with fluids and in specifically the change in state that is between liquid and gas. It was found that a reduction of pressure would increase rates of evaporation, which in turn reduced the temperature of the liquid. In the 19th century, these processes mobilize in a range of mechanical systems that formed the foundation of today’s extensive refrigeration and air-conditioning industry. Prior to the development of machines for extracting heat, the main way to provide cooling in amounts suitable for commercial application was by harvesting and transporting ice. Although it had the unfortunate habit of melting in transit, ice was still of great value in manufacturing processes such as brewing lager, or in preserving shipments of perishable goods, especially meat and fish.
Even when mechanical systems were progressed, they were often used to make blocks of ice that could then be easily distributed to provide cooling. In buildings, for example, air could be run over ice before being publicize using fans. These systems were originally used in spaces holding large numbers of people, especially theatres and concert halls, where fenestration was limited to avoid disruption. But the build-up of humidity from the ice, and from the people in the space, generates various problems, including a maximizing risk of condensation. It was not until the work of Willis Carrier in the early 20th century humidity as well as temperature, and thus avoids the problems linked with water vapour.
2.3 Buildings and Nature:
In normal contexts, the room, the simplest form of shelter, expresses the most benign potential of human life. It is, on the one hand, an enlargement of the body: it keeps warm and safe the individual within; like the body, its walls put boundaries around the self preventing undifferentiated contact with the world, yet in its windows and doors, crude versions of the senses, it enables the self to move out into the world and allows that world to enter. But while the room is a magnification of world, of civilization. Although its walls, for example, a stable internal space ‘ stabilizing the temperature so the body speeds less time in this act; stabilizing the nearness of others so that the body can suspend its rigid and watchful postures; acting in these and other ways like the body so that the body can act less like a wall ‘ the walls are also, throughout all this, independent objects, objects which stand apart from and free of the body, objects which realize the human being’s impulse to project himself out into a space beyond the boundaries of the body in acts of making, either physical or verbal, that once multiplied, collected, and shared are called civilization.
With the rise to influence of the green movement in recent decades, the term environment has come to be associated with the natural ecosystems of the earth, remarkably as they are increasingly warned by human technological activity. But for architects, the word has been used in a more broad sense, to portray the various spaces accommodate by humans, both built and natural, such as in the terms built environment and environmental design. Architects are often thought of as the designers of buildings, but for many architects, a building is only a means to create an environment in which people can live and work, and to determine the level of intercommunication with the world outside. Buildings modify nature, so that the people within can enjoy sunlight, natural air and views, but without disclosure of rain or harsh climatic conditions. The very reason buildings are designed and constructed is that the natural environment is irrelevant for a large number of human activities, except when altered by the walls, windows and roof of a building.
Ofcourse, buildings do more than simply modify the outdoor environment. They can express a sense of identity for individual owners or designers, or collectively for a society or a nation; they can be seen as manufactured objects generated by a building industry, or as phenomenon of the technology of construction; they can act as venture for owners or developers speculating on rising values; or they can even be targets for military or terrorist campaigns, with overwhelming rise from the fundamental and ongoing need to modify the environment in order to facilitate social and cultural activities that are essential to human life.
2.4 Air and Buildings:
Because of the pressure of the atmosphere, the air we need to breathe usually finds its way into every space of every building, if not through open windows or doors, then through cracks or gaps between the various elements that make up the building enfold. Either inside or outside of buildings, we are immersed in air. It is important to have the right character of air in any given space. The issue of air quality emerge partially because of its oxygen content, but also because air is a medium that carries many other facet of the environment, including heat and moisture, smoke and odors, dust and insects, sound and noise. The challenge with ventilation system is attaining by letting in the natural air because it reduce the contamination, odors and other fumes that are hazardous for the health or human survival in indoor or closed spaces. Unfortunately, this ideal is often negotiated by air-conditioning systems that are poorly designed or maintained and that minimize access to outside air in order to maximize their own efficiency.
Due to the complicated nature of the ventilation requirements for the buildings, the breathing building ventilation strategies must be imported in the buildings to develop a low energy solution. The University of Hertfordshire Law Court Building has recently been awarded ‘The Most Sustainable Construction Award 2011’ by Building Futures and has been short listed for several other awards. So it is the best example of the naturally ventilated buildings.
The University of Hertfordshire Law Court Building is designed as an inventive building with leading facilities, including a full-scale courtroom with public gallery, a working law clinic, a purpose-built mediation centre and a dedicated CPD suite, as well as a large number of offices and classrooms. Effectively and efficiently ventilated building, is meeting the summertime overheating criteria. It is delivering fresh air and a quiet environment so that students can concentrate ensuring minimal energy utilization.
Figure 2.2 University of Hertfordshire attenuated roof terminal
Figure 2.3 The University of Hertfordshire Law Court building
3.1 Natural Ventilation:
The transit of air through buildings is essential in order to provide a formal supply of oxygen to the habitants and also to take away the heat, water vapor and carbon dioxide that they produce. Since buildings usually have openings in the form of doors and windows, air flow through it as a result of the ‘natural’ flow of air in the atmosphere. When sunlight heats the ground, then the ground heats the air and the air expands to create a zone of high pressure. Air will then move from the zone of high pressure to any zones of lower pressure around it, resulting in breeze or wind. When moving air confronted an object, such as a building, the air must move either through it or around it to reach the other side. The physics of air flow is extremely complex, and authentic modeling will generally require the use of fluid dynamics. However, there are several key factors that resolve how much air will move through the building. These are the speed and direction of the wind, the size of the opening through which air enters the building, the size of the opening through which the air goes out of the building and the amount of friction experience in-between resulting from contact with interior surfaces and objects. The quality of air can also be affected by locating windows adjacent to water or green space, which can partially cool and filter the air before it enters a building.
Cross – ventilation
Figure 3.1 Cross-ventilation
Ventilation from one side only
Figure 3.2 Ventilation from one side only
Ventilation from stack effect
Figure 3.3 Ventilation from stack effect
Natural ventilation started from history according to the different climates. Architect, planner, activist and theoretician, Charles Correa of India has gained his place as a major figure in contemporary architecture. His contribution to design and planning has been internationally recognized and he has received several major awards including an Honorary Doctorate from the University of Michigan in 1980 and the 1984 Royal Gold Medal in Architecture. One of his project is Kanchenjunga Apartments, located in Mumbai, India is the best example of naturally ventilated buildings. In Mumbai the climate is hot and rainy, so the buildings are oriented to east west to catch prevailing winds and also to get the best view as it sea facing, but also the brunt of the hot sun and heavy monsoon rain.
Charles Correa, in his design strategy used verandahs all around the living spaces as a protection. Building is oriented according to the flow of air to facilitate the moment of cool air into the apartment. Due to the energy crises and complexity of installation and for the new line of evolution people started using natural ventilation.
Figure 3.4 Flow of Air in Kanchenjunga Apartments, Mumbai.
Another example of the natural ventilation system is Shahajahanabad house also located in India. This is the typical section through the Shahajanhanabad house. To facilitate the moment of cool air into the house, parapets are not built towards the courtyards.
Figure 3.5 Typical section of the Shahajanhanabad house
3.2 Indoor Air:
In the past half century, air conditioning has changed from being extremely rare to extremely common. What was once used mainly in cinemas and retail outlets to attract consumers is now integrated in nearly every public or civic building, and the number of dwelling is rapidly increasing due to lower costs. One result has been a rise in expected zones of comfort in indoor environments but it also causes problems besides its benefits. Systems that are partially maintained or cleaned can perform poorly in terms of filtering the air, and the water removed as condensate at the point of cooling can become contaminated with biological agents, one of the most dangerous being the legionella bacterium, which can prove fatal to building occupants. Other problems arise from the large percentage of air being re-circulated, which can be up to 80 percent in typical systems. percentage of building-related illness or sick building syndrome, where inhabitants suffer a physiological reaction to building contents or systems, are often compounded when the origin of the reaction is kept inside the building by the ventilation system.
However, even when these problems are avoided through better material, it is still possible for habitants to feel tired or drowsy when exposed to particularization air throughout the course of a working day. Also, people will often be more patient of variation in temperature resulting from changes in the natural environment than from air-conditioning systems. Studies have found that a vast temperature range is tolerated by those who have a level of control over their thermal environment, such as the ability to adjust air flow rates to operate a window, than by those who are subjected to a centrally controlled system. Fortunately, people understand that keeping down the costs of the air-conditioning system makes no sense if it makes the people inside less effective. So bringing the innovation in ventilation system by introducing natural air in have attempted to address these problems by reducing recirculation rates and increasing user control.
3.3 Healthy Air:
The need for oxygen and the hazards of carbon dioxide were complicated by the emerging science of chemistry and by the still-prevalent miasma theory of disease. Proceeding to the discoveries of Louis Pasteur and his time in the late 19th century, most diseases were thought to be contracted through exposure to foul air, noxious gases or vapors. Windows were kept closed to prevent exposure to the stinking air that continuously permeated cities before urban sewage systems were constructed. However, one advantage of the miasmic theory of disease was the development of ventilation systems for hospitals. Designs by architects from the French Academy in the 18th century show patients separated into individual beds, enabling the free flow of air around the body to prevent stagnation and encourage healing. As germ theory became more vividly accepted, these principles were applied to other buildings. One of the key aims of modernist architecture was to design buildings that allowed more light and air into the interior to improve health by removing germs.
3.4 Amount of time spent indoor:
The average person spends the amount of time indoors has severely increased due to a number of compounding factors. Due to the postwar era, there’s a tremendous demographic shift from rural to urban life styles. As a result of this change in life style increased the activity span indoor, for example, work has become the predominant indoor activity that occurred in factories and offices. As well as the other activities like sports and shopping has also shifted majorly in indoor functions. These factors resulted in increased dependence on the automobile has reached to a point that average person presently spends over 90 percent of their time indoors.
Figure 3.6 Pakistan industrial development corporations, office building Figure 3.7 Habib bank plaza
Figure 3.8 Hamdard hospital Figure 3.9 TCF school
Figure 3.10 Shopping centers
3.5 Parallel walls strategy:
One of the simplest, oldest, and yet most enduring of architectural strategies practiced in Pakistan is based on two straight parallel walls, and specifically talk about Karachi where there is urbanization increasing day by day, so the fast urbanization is not only the main reason of the congestion and introducing more high rises but there are also a lot of social and environmental factors that are involved in it like increasing land values and specification of land use for green spaces. So based on parallel walls, buildings and dwellings are the major part of the urban culture so it needs to be sustainable though. It is the fact that the built environment is also a major contributor to global environmental problems because carbon emissions have been increasing from past twenty years.
Parallel walls strategy is found in the prehistoric architecture, and it continues to be applicable. Architects have explored its possibilities right into the twentieth century, developing variants and hybrids. It is unlikely that its potential has yet been exhausted. And obviously it is attracted to the designers and structural engineers because of its simplicity and uncomplicated form as compared to any other form. That’s so easy to put roof on the parallel walls.
Figure 5.1 Parallel walls Figure 5.2 spanning a roof on parallel walls
Figure 5.3 A space organized by parallel walls
Figure 5.4 Saddar town Figure 5.5 Karachi Old town
Figure 5.6 Gulistan-e-Johar Area
These are the pictures of the local areas of Karachi Saddar town, Karachi old town and Gulistan-e-Johar respectively, structures based on the parallel lines. So there’s no such problem with the building shape because as explained above there are a lot of factors involved but due to this congestion there’s generate a poor ventilation problem that cannot be tolerated because this is the point of occupant’s health and comfort.
3.6 Analyzing through history:
These characteristics of the parallel wall strategy are to be found in some of the most ancient buildings on earth. In the nineteenth century the archaeologist Heinrich Schliemann discovered a city thought to be the ancient city of Troy, made famous by the stories of Homer. Some of the houses he found there were based on the simple form of two parallel walls to have taken advantage of the focusing power of parallel walls. This comes about by combination of the line of direction, the convergence of perspective lines, and the frame created by the walls with the roof above and the ground below.
There were a lot of temples and churches made on this parallel lines strategy. Vincent Scully, in his book The Earth, the Temple, and the Gods, suggested that the ancient Greeks used the sense of direction and focus created by parallel walls to relate their buildings to sacred sites on the peaks of distant mountains. So there they take care of the ventilation process and the flow of air inside the buildings to make it habitable.
Figure 5.7 Parallel line strategy in Churches
Talking of the 20th century, architects have started experiments with the parallel walls as a basic organization of spaces, also by keeping the factor of light and ventilation in mind and applying them in their designs. For achieving light and air they tried innovative ways such as by reducing the parallel walls strategy to its most basic form.
The Student Chapel at the University of Otaniemi in Finland planed on the same strategy, mainly working on plain walls but with providing inlets for light and ventilation by cross walls.
Figure 5.8 The Student Chapel, Finland, Plan and Section
There’s another example in housing as well. There is a low cost house, named Tube house designed by Charles Correa for a hot climatic region. The use of parallel walls shows that it can be almost endlessly repeated. Private upstairs sleeping accommodation has found by the irregular section, but with the openings in the roof, it also allows ventilation through the house.
Figure 5.9 Tube house by Charles Correa, Plan and Section
4.1 Comfort and Sensory Experience:
Whether attain using passive or active systems, the technology of architecture is planned to create spaces convenient for human habitation, making a level of comfort and facility that enables the various activities within buildings to be initiated. In its real form, comfort meant mitigate the pain and weakness by strengthening or bracing. But, as Sigfried Giedion observed, comfort became tied to a sense of domestic ease and pleasure afforded by the newly available furnishings and domestic appliances manufactured in the 19th century. Comfort can foster human achievement by reinvigorating the body after the demands of work. Or comfort can result from machines performing work on our behalf, using energy from fossil fuels to replace the labour of human hands. Alternatively, comfort can be seen in terms of remaking the world in a way that is sensitive to human suffering, and reducing the effort required to meet the requirements of the body. This allows mind to be focused away from the body and outward into the world at ever-increasing distances.
Unfortunately, the use of active systems has increased assumptions about levels of comfort, leading to increased use of resources of energy, water and materials needed to make buildings comfortable. This is problematic for several reasons. Firstly, once levels of use have increased, it is difficult to lower them again. Secondly, the resources used in providing comfort are used but not directly, the result of ‘inconspicuous consumption’ where it is difficult to know how much people are using or difficult for people to know how much is being used on their behalf. Hardly, it may be possible to provide too much comfort, reducing the body’s ability to change or adapt to its environment when it becomes necessary.
For example, active systems save us from the task of thermal regulation and it is now achievable to enjoy ideal comfort surroundings in the home, at work and in the car. The result, while relaxed, can lead to a sense of monotony or routine, dulling the senses from a lack of variation. To modernize themselves, people often take vacations in diverse climates, such as the heat of beach resort or the cool of mountains or snowfields. Sometimes the enjoyment of thermal extremes is more usual, as with Japanese or Turkish baths or Finnish saunas.
And when saunas involve rotating between the heats inside and the cold water or even snow outside, the aim appears to be more than just neglecting the weather. It may be that this challenging sensory experiences- the thermal equal of severe sports, perhaps- is a way to exercise the body’s thermal response mechanism, improving the ability to resist the change confront in daily life.
4.2 Environmental Diversity:
Avoiding the need for adjustment can prohibit distraction, but it can also lead to weakness and make spaces feel bleak. It is possible that stress can result from too little stimulation and too mush as well and that a small degree of improvement throughout the day is helpful to keep the senses active. Buildings can protect from intensiveness of environmental change, but by linking with external space, can also allow us to enjoy the changes that occur naturally throughout the day and year. Changes resulting from natural variation are also more likely to be bearable by building users, with the flicker of a candle, for example, being far more pleasant than the flicker of a faulty light fitting.
The need for degree of sensory stimulation highlights the importance of environmental diversity in architecture. Much of that diversification can result from the formal and dimensional innovation of architectural projects. It can also result from the way buildings are designed to grasp changes in the external environment and bring them in to the building interior.
In Shoei Yoh’s Light Lattice House in Nagasaki (1980), for example, a fine grid of sunlight paths its way across the interior throughout the course of the day. This will happen with most windows, but can be focused or highlighted by considering the pattern of sunlight on the ground or by making its place on the floor.
Because architecture is three-dimensional, it allows the scope for both spatial and physical change. As people move towards, into and around any building, they are able to experience its forms and spaces from different locations, enjoying diversity simply by changing position in relation to the building and its external environment. By actively creating diverse environmental conditions within the various internal spaces, an architect can create a rich sensory environment for habitants as they move from dark to light, from cool spaces. Our senses can be brought alive by the experience of architecture.
Through variation in form and space, material and use, temporal change and adaption, architecture can provide a diversity of experience for all the senses. However, this diversity is often neglected because of a view that architecture is concerned mainly with the visual appearance of buildings. Juhani Pallasmaa has identified that the dominance of vision in our society had led to a lack of consideration of other senses. He argues for the need to consider the rich complexity of human experience, by considering the effect of touch and taste, sound and smell, in architecture.
4.3 Active and Passive Design:
Buildings affect the flow of energy, of heat, light and sound necessary for people to stay alive and to engage in social activities. They also affect the air we need to breathe and the water we need to drink and wash, and the way they, too, play a part in social space. Each building element will have a different degree of permeability, depending on materials and construction techniques. Often these elements are built up of several layers to improve performance, which can be enhanced by the quality of jointing and details. Alternatively, spaces can work together to have a cumulative effect, such as a walled garden or courtyard that can act as an intermediate space between the interior and the surrounding environment.
Sun, heat, light, sound, air, water and fire are the forms of energy and matter that flow in an around buildings, making them habitable and bringing them to life.
Talking of ventilation in the buildings air is the essential element, cooling air increases its relative humidity, it may be necessary to remove moisture from the air to prevent it from feeling damp. The strategy employed by Willis Carrier in the design of his air-conditioning system was to lower the temperature of air below what was needed until a saturation point was reached that would give the required moisture content, then raise the temperature of the air back up again, thus adjusting its relative humidity to a precise and predetermined level. The actual saturation of the air was achieved using sprays, but the overall consequence was generally the removal of moisture at the point of cooling. The process of modifying humidity as well as temperature was particularly useful in industries where accuracy could be affected by expansion and contraction or rates of drying, such as color printing. Here the added cost of conditioned air was offset by the avoidance of waste and the benefit of reliable production outcomes.
Similar advantages were promoted to owners and tenants of office buildings as air-conditioning began to be introduced in the United States in the late 1920s. Although buildings were fitted with operable windows, ducted air entering from the corridor meant that these no longer needed to be opened; cleaning costs were reduced by keeping out dust, workers were less likely to be distracted by noise from outside, would be more comfortable from the cool air would have greater control over the air flow. While some air-conditioned buildings were made with sealed external glazing, such as Frank Lloyd Wright’s Johnson Wax Building in Racine.
Frank Lloyd Wright’s Johnson Wax Building in Racine.
Figure 4.1 Johnson Wax Building inside space Figure 4.2 Johnson Wax Building
The construction of buildings without operable windows has been commonplace ever since. The relatively low cost of energy and high cost of construction mean that it is usually cheaper and easier to seal external walls and use an air-conditioning system to modify the climate within. However, the increasing concern for sustainable design, through both reduced energy use and improved indoor air quality, is leading to a greater usage of natural ventilation and mixed-mode systems. It is perhaps ironic that the arguments for reducing the reliance on air-conditioning systems, such as improved worker heath and productivity, are the same as those made for introducing them half a century ago.
4.4 Case Study: The Torrent Research Centre in Ahmadabad, Abhikram:
‘Developed societies, with their sustained focus on the increasing importance of individuals, have made mechanical cooling an inherent necessity in any modern building in semiarid regions of the world. Consequently, a majority of the buildings designed in such regions assume the use of artificial lighting and air-conditioning systems, even during daylight hours, for achieving human comfort conditions. For many years now, through our architectural practice, we have been trying to establish that such assumptions are a myth, in addition to being detrimental to the objectives of resource conservation, particularly for the developing countries like India.’ Nimish Ptel and Parul Zaveri.
Figure 4.3 The Torrent Research Centre, Ahmedabad
The Torrent Research Centre is in the outskirts of Ahmadabad, India. It is the complex of research laborites with all the facilities and infrastructure. The Passive Downdraft Evaporative Cooling system is used in the building, which is basically a large office building that shows it is possible to get human comfort without any mechanical systems or regular HVAV systems in dry hot regions as well.
Figure 4.4 Passive Down Draught Cooling system working in Research centre
Passive downdraught evaporative cooling in torrent research centre, Ahmedabad.
‘ Passive downdraft evaporative cooling systems consist of a downdraft tower with wetted cellulose pads at the top of the tower.
‘ Water is distributed on the top of the pads, collected at the bottom into a sump and re-circulated by a pump.
‘ These towers are often described as reverse chimneys.
‘ While the column of warm air rises in a chimney, in the case the column of cool air falls.
‘ The air flow rate depends on the efficiency of the evaporative cooling device, tower height and cross section, as well as the resistance to air flow in the cooling device, tower and structure into which it discharges.
Figure 4.5 Evaporating Cooling System, Plan and Section
It is learnt from studying the passive techniques that have been incorporated and efficiently working in the same climatic conditions as in Karachi. So it is possible to get the positive results by understanding the advancement in the materials and passive cooling techniques that we can apply and can make our indoor health of the buildings habitable for the dwellers.
Analyzing the local Architecture
5.1 Local Atmosphere:
Summer season in Pakistan is hot and humid with about seven month cooling season. The conditions of weather of Karachi are characterized by high humidity and high temperatures.
Figure 5.1 Psychometric representation of Karachi’s climate
So because of high temperature and hot climate increase in the use of air conditioning systems has resulted in maximizing the demand for electricity that is produced in central power plants. Especially in case of Karachi almost all of the electricity is generated by thermal power plants by burning fossil fuel [PEYB, 2005]. The air-conditioning systems, which create a large number of air conditioning plants, use high grade electric power. Because of high ventilation loads buildings have a large suppressed cooling load [Daou, 2004]. The buildings that have high ventilation requirements are those which are densely occupied such as theaters, convention centers, apartments, institutions and super marts.
5.2 Ventilation approach:
Good ventilation is very essential to achieve healthy and productive habitable conditions in a building. Along with temperature and humidity, fresh air is the major icon to determine the quality of indoor healthy living conditions.
Recent research indicates a divert association between indoor air quality and fresh air ventilation rates which supports requirements for building assure safe and healthy interior air environments (Seppanen, 2002). Realizing the importance of healthy indoor conditions (ASHRAE) American Society of Heating Refrigeration and Air Conditioning Engineers has increased the recommended ventilation air flow for almost all buildings.
The historical evaluation of the ventilation systems in the buildings must be kept in mind that these were working before on completely natural ventilation methods but now the mechanical systems are more in use so the whole system needs to be re-conceptualized by stacking effect in ventilation incorporating technology and natural ventilations methods.
For example if we compare the building structure with the planning and designing strategy in terms of materials, structural systems then we can come to some point and make a conclusion regarding resolving the ventilation problems.