Lights and air conditioning account for a large portion of energy consumption in buildings. Energy efficiency is the ability to reduce the amount of energy consumed in a building. There are many methods of achieving energy efficiency, such as designing low-energy appliances, retrofitting existing buildings, and choosing more efficient materials. This article will explain the principles of Energy Efficient building design.
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The energy efficiency of buildings is one of the most important issues to be solved in our society. They can make a huge difference, both on the environment and on your pocket. In this article we will describe the principles of an Energy Efficient building design.
Principles of energy efficient building design
1. Thermal Comfort :-
Thermal comfort is an important factor for any human being. It is the body’s natural reaction to external temperatures and it helps the body maintain its homeostasis (internal equilibrium). When there is a change in temperature, our body reacts by sweating, shivering, or moving away from heat or cold.
Thermal comfort is complex and there are many influencing factors. Mainly temperature, humidity and air movement. We feel reasonably comfortable within a range of temperatures. This science is expressed as the Adaptive Thermal Comfort Model which is commonly used in India. The comfort standard varies and has an impact on the affordability of adopted measures to achieve comfort. Based on the accepted definitions of thermal comfort, this project shows designs of residential buildings in a way that minimizes the need for electrical heating or cooling - the worst culprit being refrigerant based air conditioning. Thermal comfort is the crucial aspects for Energy Efficient building design.
2. Passive Design :-
Most of the buildings are designed with a passive approach, where the building is designed to absorb rather than reflect the environment. Passive design is a good choice for new construction, especially where there are no future changes in the climate. It's ideal for affordable housing and low-income housing since it does not have to accommodate any future changes in climate or building codes. Passive design can be applied to new construction as well as alterations and additions.
The configuration of the building plan and the design of the building’s external envelope – its external walls, windows, shading elements and roof - contribute to the building’s environmental performance. Working out optimal designs combining the effect of each of these elements is ‘Passive’ design. The idea is to maximize the duration of comfort by Passive design in the living spaces so as to minimize the need for either heating or cooling by energy consuming devices. The Type Designs shown in this project are derived by optimizing Passive design. Passive Design is the important aspects for Energy Efficient building design.
3. Compactness of building plan :-
The trend towards compact urban development is gaining momentum across the world. With its increasing population, India is no exception to this. In order to save energy and ensure that buildings are Eco-friendly, it is essential to build smarter with a compact design. Compact building plans enable better control of the structure's envelope and direct sunlight for maximum thermal gains.
This principle requires minimizing the external wall area while planning the arrangement of dwelling units -whether as a single unit on its plot of land or as a group of units. Lesser the area of exposure of the external envelope to the outside, for a given floor area, lesser will be the heat transfer into the building. Simple rectangular shapes are more efficient.
Similarly, adjacent units can share walls and thereby reduce their exposure to the outside. These simple methods of achieving compactness in planning also reduce the cost of construction. It is the key aspects for Energy Efficient building design.
4. Window to wall ratio (WWR) :-
Window to wall ratio (WWR) is a calculation that compares the size of an interior window with the size of a wall in relation to its dimensions. The WWR can help you figure out if you are using too much space, or not enough. It's especially useful for narrow and small spaces where you might be able to use more windows than walls.
The external perimeter that separates the outside from the inside, is made up as walls and windows. Opaque masonry walls will have a greater capacity to resist the flow of heat compared to windows. The larger the ratio of window are to wall area, the greater the flow of heat from outside to the inside. Window to wall ratio (WWR) is the major Principle for Energy Efficient building design.
5. Insulation :-
The goal of any building is to ensure that its inhabitants are protected from the heat, cold, and moisture of their environment. Unfortunately, this is easier said than done. Insulation helps buildings manage these properties efficiently. The insulation that is used in building differs from place to place but generally contains a variety of materials such as mineral wool, rockwool, cellulose fiber batts, expanded polystyrene (EPS), fiberglass batt insulation and glass wool batts.
Heat will flow across the building envelope - its walls, roofs and windows, whenever there is a difference in temperature between the inside and outside. In order maintain the indoor temperatures within the comfort range this flow of heat needs to be controlled. Insulating the roof is critical. Walls too need to be insulated. Windows tend to be the weakest link – the thin glass and a conductive window frame material are the culprits. PVC or timber frames with double glazing will be advantageous, especially when the room is being air-conditioned. Insulation is the key Principle for Energy Efficient building design and Energy Savings.
6. Shading :-
The size of a building determines the light it can receive. The smaller the building, the more exposed it is to direct sunlight and the less shade there is. Shade reduces temperature and increases comfort in buildings, especially during summer months. It can also help protect against water damage, reduce energy consumption, and save on cooling costs.
This is the most neglected aspect of design for comfort and energy conservation in buildings being built nowadays. And it is often the chief cause of discomfort, which then pushes occupants to resort to expensive, energy guzzling, air conditioning. Direct sunshine and indirect sky radiation entering a room through a glazed window is the largest contributor to discomfort during warm and hot seasons. Direct sunshine must be blocked and diffused radiation should be filtered. Shading elements are designed according to the direction from which the unwanted sun would strike the window.
In winters and in cold climates, however, sunshine would be welcome. Glass panels can let in direct sunlight and ‘trap’ the heat absorbed by the room. Insulating double glazed windows will help in retaining the warmth through the night too. Shading is the major Principle for Energy Efficient building design and human comfort.
7. Ventilation :-
So what exactly is ventilation? Ventilation is an important component of healthy buildings and homes. In fact, it can be a life-saver. Ventilation helps remove pollutants from the air, keeping us breathing clean air in our homes.
When the air outside is pleasant and cooler than the inside we open our windows to flush out the heat. How effectively and quickly this brings relief from stuffiness and makes the rooms comfortable depends on how quickly the inside air is replaced by the more pleasant air. Windows that open fully, like casement windows, will be more effective than sliding windows which can open only partially. High level ventilators and cross ventilation that allows air to flush through the room helps a great deal, but when it is too cold or too hot outside windows and doors must shut tight, leaving no cracks or gaps through which the unwanted air can infiltrate. This is most important when you are air conditioning a room. Use of mechanical ventilation with heat recovery / energy recovery becomes important in such cases.
When there is no breeze the process will be slow. At such times an exhaust fan that assists the ventilation process will help greatly. In this project we assume the occupants make good use of the provisions for ventilation in the designs of the dwelling units. Ventilation is the major Principle for Energy Efficient building design and good health.
8. Thermal mass :-
Thermal mass is the amount of heat retained by a building material in response to a change in its temperature. In nature, plants and animals are made up of materials that store heat. Plants absorb solar energy during the day and emit it at night. The earth itself also retains large amounts of heat. These natural sources are often referred to as living thermal mass.
Dense and heavy elements of the building, such as the floors and masonry walls, act as temperature stabilizers. Their temperature varies relatively little through the day and night cycle. They can ‘store’ heat as well as coolth. This property is referred to as thermal mass.
In warm climates the trick is to open the windows during the cool period of the evening and nights to store the coolth in the heavy inner floors and walls of the house, and to shut the windows during the hot part of the day to keep the inside of the house from getting heated up. In cold seasons, the warmth of sunlight let in through glass windows will be stored in the floors and walls. The walls must be insulated on the outer face of the thermal mass to retain the heat in the thermal mass and to retain warmth for the night.
9. Solar Power :-
Installing a Solar PV System will allow you to generate renewable energy and reduce your electricity bills. This will pay itself off over time, so a definite worthwhile purchase if you’re planning on staying in the residence long term. There are battery storage solutions now available, such as the Tesla Powerwall, but these still have long term return of investment (ROI), but if you purely believe in reducing your carbon footprint over ROI, this may be a viable decision for you to make. Solar Power or Clean Energy is the Key Aspect for Energy Efficient building design, Energy and Environment Conservation.
10. Energy Efficient Appliances :-
When choosing fridges, televisions, washing machines, dishwashers and so on, choose energy efficient appliances with the highest energy ratings. Even if you pay a little more for these appliances, they will save you money over time. Energy Efficient Equipment with BEE Star labeled is the major Principle for Energy Efficient building design and reduce electricity bill.
The principles of energy efficient building are the basis of any good policy and legislation. This article shares 10 principles that are essential to sustainable and energy efficient building designs. Always consider above principle when you construct or modified your building.
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FAQ of Energy Efficient Building Design
Q: what is Thermal Comfort? - Thermal comfort is the temperature at which you feel comfortable. - It's measured in degrees Celsius or Fahrenheit. - The higher the temperature, the more uncomfortable you will be. Q: what is passive design in building? - Passive design is a method of building that uses the natural forces of wind and gravity to create an environment that is comfortable, healthy, and safe. - It's about creating a space where people can live in comfort. Q: Why is building insulation important? - Insulation is important because it keeps the heat in your home. - It also keeps the cold air out. - It can help you save money on your energy bill. Q: Why shading is important in designing a building? - Shading is important in designing a building because it helps to create the illusion of depth. - It also helps to make the building look more interesting and realistic. Q: Why ventilation is important in designing a building? - Ventilation is important because it helps remove the carbon dioxide and other harmful gases from a building. - It also keeps the air fresh and clean. - It prevents mold, mildew, and bacteria from growing in a building. Q: How do you use the thermal mass of a building? - Thermal mass is the ability of a material to absorb and store heat. - It's used in buildings to keep them warm in winter and cool in summer. - It can be made from concrete, bricks, or wood. Q: What is the need of energy efficient building? - Energy efficient buildings are more comfortable and cost less to run. - They use less energy, which means they are cheaper to operate. - They can be built in a shorter time frame than traditional buildings.
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