Winston Churchill said, “we shape our buildings and, in time, our buildings shape us.”
The relationship between People, Climate and Buildings is non- linear and complexly interdependent. Changes of temperature with time can cause discomfort if they are not under the control of building occupants. The building fabric is a critical component of any building, since it both protects the building occupants and plays a major role in regulating the indoor environment. Consisting of the building’s roof, floor slabs, walls, windows, and doors, the fabric controls the flow of energy between the interior and exterior of the building.
It is often difficult to anticipate indoor environmental quality problems since prevailing materials and construction practices change faster than scientists are able to evaluate their potential health impacts. Health and comfort can also be affected by physical factors, such as lighting and heat, and by the physical organization of the space. The air-handling systems can affect the amount of moisture in a building and thereby prevalence of upper respiratory tract symptoms. Building design, operation, and maintenance can all have critical impacts on worker health and well-being, and some interventions have been found to improve health.
The building fabric must balance requirements for ventilation and daylight while providing thermal and moisture protection appropriate to the climatic conditions of the site. Fabric design is a major factor in determining the amount of energy a building will use in its operation. Also, the overall environmental life-cycle impacts and energy costs associated with the production and transportation of different envelope materials vary greatly.
There is term called Thermal comfort is influenced by factors that affect the way the body loses and gains heat. Other than the critical component of temperature, these factors include:
- Air movement (breezes or draughts)
- Radiant heat sources (e.g. direct sunshine) heat sinks (e.g. cool surfaces)
Thermal comfort can be considered generally as a range of temperatures that is influence by these factors. For example, a higher temperature may still be comfortable.
If cross-ventilation is present, while high humidity will reduce evaporative cooling and lower the upper temperature limit.
What we have discussed above is scientific reason behind what we face in our daily life. Generally what happens are maximum temperatures usually occurring after noon and minimum temperatures in the early morning. The range varies according to location, with high variation in continental areas, and low variation in maritime areas.
Diurnal temperature variation
A second important factor in fabric design is what occurs inside the building. If the activity and equipment inside the building generate a significant amount of heat, the thermal loads may be primarily internal (from people and equipment) rather than external (from the sun). This affects the rate at which a building gains or loses heat.
Building Configuration also has significant impacts upon the efficiency and requirements of the building fabric. Careful study is required to arrive at a building footprint and orientation that work with the building fabric to maximize energy benefit.
Transmission loss through ground floor
In keeping with the whole building approach, the entire design team must integrate design of the fabric with other design elements including material selection; daylighting and other passive solar design strategies; heating, ventilating, and air-conditioning (HVAC) and electrical strategies; and project performance goals. One of the most important factors affecting fabric design is climate. Hot/dry, hot/humid, temperate, or cold climates will suggest different design strategies. Specific designs and materials can take advantage of or provide solutions for the given climate.
As we have already discussed that building fabric Consists of the building’s roof, floor slabs, walls, windows, and doors, the fabric controls the flow of energy between the interior and exterior of the building. We have to seriously think of alternatives that can be more effectives yet environment friendly. We have been using glass in buildings, is glass the best option we have? Although the glass facade looks striking, glare remains a major problem. As most glass curtain walls cannot be opened, ventilation is another issue that needs special attention. Glass is also poor in terms of heat preservation, leading to higher costs in the operation of air-conditioners. I am not against using glass in building design; then what else below mentioned are examples
“In a desert country like Qatar that is sunny all year round, it is not logical to build towers with glass facades that attract the heat of the sun to the inside of the building. The air conditioners will need to use more power to be able to cool the heat that was attracted to the building through the glass façade. There are alternatives to glass and aluminum facades. We can use stone for example in the facades, it will look good and it is in line with the desert environment. This doesn’t mean going back to the past, but to respect and develop elements of the past according to the changing needs and requirements of modern life. “We need to combine old and modern elements to come up with a new architectural style. It’s just an example of how people have already started thinking about using alternative building materials.
A more sensible way of designing a building is to take the environment into consideration when designing the building in the first place. When we work with nature like this, the need for mechanical and artificial heating and cooling is reduced, with considerable savings in energy use. This saving is not just financial, but also environmental.
Orientation of your property to maximize natural resources, and eliminate un-necessary heating & cooling. Understanding the path of the sun and it’s angle in the sky at various times of year is key to working with nature in order to reduce energy costs.
Sun Path Diagram
The sun rises daily in the east and sets in the west. In summer in North America, it will pass almost directly over-head at noon, whilst in winter its path will be low in the southern sky. This is true for any location north of the equator, and the further north you go, the lower the sun will be in the southern sky – south of the equator the sun follows a path that is low in the northern sky.
Therefore, to let the sun inside the house in winter, most windows should be on the southern side. Windows on the east and west tend to lose more heat than they gain in winter and they can cause overheating in summer since they receive hot morning and afternoon sun. A roof overhang over southern windows shades the windows in summer while allowing sunshine in during winter, due to the lower position of the sun in the sky – the sun shines in under the overhang to heat the inside of the house
If the sun is allowed to stream in through a window, the room will warm up. If there is a concrete floor or thick walls, they too will warm up and stay warm for a long time and release heat slowly into the room after the sun has gone down. The walls and floor act as thermal mass to store the heat gained. Stone, concrete, brick, adobe and rock chips are all good thermal storage materials, which can be incorporated in walls, floors and a fireplace.
Cooling a Building
Besides providing heat during winter, successful climate sensitive buildings are cool in summer. Sufficient overhang protects the south facing windows from the high summer sun while at night, the house must be well ventilated to cool the place down. Insulation and thermal storage that retain heat in winter will keep the building cool during hot days.
In very hot climates ventilation is important. For example, a front porch is used to cool the air before it circulates through the house via the windows, which open on the porch. Plants and trees are also cooling, preventing heat to be reflected off bare ground while deciduous creeper growing over a porch will shade it in summer and let the sun through in winter when the leaves fall.
The skin of a building is made up of various materials, which may reflect, absorb, store, transmit or resist heat. In winter, retarding heat loss is as important as admitting sunlight, so the roof needs insulation, normally in the form of a ceiling with additional bulk insulation on top.
A wide variety of commercial insulation materials are available on the market, or in low-income houses, a layer of crumpled newspaper is better than no insulation at all, but fire risks should be considered. The curtains help to insulate windows while in very cold climates people use double-glazing (two sheets of glass with a gap between them) to reduce heat loss through windows. Similarly, a double wall (a double brick wall with an air gap in between) can be used to prevent losses and gains through walls.
The shape of a building is also important from an energy point of view. A tall, slender building has a high surface area to volume ratio. Ideally a building should be compact, with a low surface area to volume ratio, since the building’s surface is the element through which the heat transfer occurs.
Some practical advice….
- Ceiling / loft insulation will reduce the need for heating the home and could reduce energy costs by 50%
- Plastering is an excellent method for insulating walls, as it improves the moisture resistance. Within walls, non conducting material such as polystyrene sheets can b used.
- Traditional building materials such as mud bricks, thatch roofs, clay walls and floors are all also excellent sources of insulation
- In North America, window and doorframes are now most often made of steel except in the coastal areas where rust is a problem and wood is the material of choice. Wood however, provides a better insulation than steel.
Climate sensitive design principles can be incorporated to various degrees in office buildings, social housing, private homes as well as apartment buildings and townhouses. Incorporating energy efficient design principles, especially in the delivery of low cost housing, would have numerous benefits to the poor families living in these houses. Low-cost houses may be cheap to build, but their running costs are astronomical. Because of the use of energy-inefficient materials, it is sometimes warmer outside the house than inside. The costs of keeping these houses heated come out of the earnings of the people who can least afford to pay them – heating can cost poor people up to 60% of their income.
Net Zero Building
There are tangible benefits through the use appropriate building fabric such as:
- Reducing extremes of heat and cold within your home, improving quality of life
- Working more with nature, the health of people working or living within buildings improves
- Energy demand reduces due to less need for artificial heating , lighting and cooling
- Savings on energy costs (electricity and heating bills), therefore releasing funds for other basic essentials such as food, clothing and education
- Financial benefits through energy and subsequent monetary savings
- Environmental benefits through reduced air pollution; which is a result of less ‘dirty’ fuels being used
- Improved air quality reduces the cases of respiratory and associated illness
- Benefit to power suppliers through reduced/eliminated peak electricity demand
A house – your home, an office – any building, can be seen as a shelter, protecting an indoor space from the weather and external elements. Our shelters allow us to maintain a comfortable environment, free from the extremes of heat or cold outside. For achieving this we need to be careful while choosing the fabric of our buildings. That will not only serve the purpose but will also help us in achieving the maximum output. Good health results in maximum attendance of the employee.
Organisations always have concerns about employee health, so healthy employee means maximum output. Better concentration for student results in better academic performance. If we will start now then our future generations will also get benefit from it. Because building we make are not only for us but for our future. Therefore let us make our future bright.