The principle of reaching energy efficiency in a building is to ensure that it employs energy within it in a manner that is effective and well governed. By verifying that a building does not squander energy, it becomes more sustainable as spends less on energy in the course of its lifespan.
Achieving Energy Efficiency Through Natural Ventilation For Thermal Comfort
Many buildings in the developed world have been designed with strong emphasis on maximizing on views and optimizing on space use. The result of this is that some spaces such as toilets and storage facilities may end up being relegated to zones of the building that are not prime. In temperate countries, the requirement of harnessing natural light and views especially during winter means that some of these services are located adjacent to the building core to facilitate servicing requirements.
Reliance on artificial ventilation may not be energy efficiency In design
However an intrinsic weakness of this model is its reliance on energy to ensure it works as required. Should there be a power failure, such facilities could cause inconvenience due to smell and noxious gases deep within the interior of the building. In addition, there is a lack of air flowing naturally deep into the spaces, which could again pose a challenge should there be any breakdown in the artificial ventilation systems employed.
Air flow within the building serves two purposes, namely provision of clean fresh air for occupants to breathe and assisting to regulate temperature and maintain it at comfortable levels. HVAC (heating, ventilation and air cooling) systems are installed to ensure that air flows properly within buildings, to create a comfortable internal environment having fresh air for users.
Today’s buildings have become larger and more sophisticated than in the past, and many modern day developers are interested in offering huge internal spaces for commercial developments. It is commonplace to see mega malls that are completely internal in their orientation, having very few external openings in proportion to the building’s size. Office spaces compete to offer best views and daylight within a space, with a view to optimize on lettable area.
Undoubtedly, these trends have led to heavy reliance on artificial ventilation as the means to provide air within these large structures. In addition, air conditioning has become a major requirement in many urban areas as they are the only way of regulating internal air and thermal conditions inside such large structures. The energy load required by these buildings is a formidable one, and become a huge drain on national energy resources.
Creation of the chimney effect to achieve energy efficient ventilation
One of the laws of physics stipulates that hot air rises as cold air falls. This is the way convectional air currents move, as hot air is lighter than cool air. Using this principle, a designer can design a structure that allows hot air to move upwards and escape. At the same time, nature will not allow a vacuum to occur and will force cool air to flow in at the cooler lower areas of the building naturally. The architect can create a space that has an atrium or upward channels, with inlets at the lower levels of the space that allow for fresh air to be drawn in. At the highest point, an opening can be created to ensure that hot air rising up the atrium or ducts can escape into the atmosphere. This is called the ‘chimney effect’.
Natural airflow within the building is achieved through this heat exchange cycle that is produced by the process of warm air rising up being replaced by cool air from below. This process is governed by nature and the continuous natural air movement can allow the proper functioning of commercial facilities such as restaurants and shops in these locations.
This principle can be utilized globally in different climatic conditions. For example in temperate countries, the chimney effect can assist to regulate interior temperatures during warm summers, and reducing the cost of having to cool building interiors during those times. In winter, heating of the building may be maintained. Within tropical countries, one may be able to use this throughout the year. Whichever the case, reductions in cost of achieving internal air comfort can be realized as use of artificial systems can be greatly reduced during the building’s lifespan.
