This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.
PASSIVE DESIGN STRATEGIES ACHIEVING EFFECTIVE RESPONSE TO LOCAL CLIMATE
Table of contentspage
This study is aimed at identifying the specific passive strategies that can be applied to buildings in a specific type of local climate to achieve a proper response to that climate. With buildings being the highest energy consumers and passive design strategies of major benefit in reduction of energy need for cooling and heating, the research will uncover the effectiveness of the major passive cooling and heat avoidance strategies in providing thermal comfort and how the choice of these is a consequence of the local climate. To achieve an exhaustive research, different literature sources where used to determine a variety of passive design strategies that are employed in different climates. From this knowledge, the strategies used at the first block of rooms at the Belum rainforest resort where identified and their effectiveness is established accordingly. The first block of rooms at the Belum rainforest resort incorporate a large number of passive design strategies providing a wider variation of comparison study. These when compared to the other blocks at resort will widen the scope of the research. Approximately 40% of household energy is used for heating and cooling to achieve thermal comfort. This rate could be cut to almost zero in through sound climate responsive passive designs.. To achieve high energy efficiency at belum rainforest resort, strategies like Encouraging natural air flow with large openings and providing shading were used amongst other not as effective methods. It can thus be concluded that some passive design strategies are more effective than others in specific climates and knowledge on this effectiveness can drastically improve energy efficiency gained due to the use of these design strategies.
Each climate zone has distinctly different design and construction requirements, This is because within each of these main zones there are also many regional sub-zones with differing local weather characteristics such as wind patterns, humidity, temperature and height above sea level.
There exists a large number of passive design strategies that can be applied to any particular building. Of these strategies, some are universal and would apply to almost all types of climates but for the most part each of these climate zones require specific types of passive design techniques to be applied to buildings in order to be effective. In addition to this, in response to the local climate, some of these specific passive strategies are more effective than others in achieving their goals and hence a degree of priority can be placed on them for easier design decision making.
Malaysia has high temperatures and a High humidity year round, to achieve building sustainability energy use for cooling has to be minimised, the major factors to consider for this climate are the wind and the sun. Most of the heat gain in the buildings is from the sun specifically solar heat gain though windows and conduction heat gain through walls. And most of the cooling is by air flow. From this we can clearly observe that the most effective passive design strategies are those that control heat gain and provide cooling through air movement.
This paper will investigate how effective particular passive design strategies employed to the first block of rooms at the Belum rainforest resort in responding to the local climate by responding to the following research questions:
- What is passive architecture design?
- What are the passive design strategies employed to achieve reduction in heat gain in the first block of rooms at the Belum rainforest resort?
- What are the passive cooling design strategies employed in the first block of rooms at Belum rainforest resort?
- How do these passive design strategies employed effectively respond to the local climate
- Passive architecture design
According to…Passive architecture design refers to a design approach that uses natural elements, often sunlight, to heat, cool, or light a building. Every passive design approach is aimed to maximise comfortable conditions for people to live in, while reducing the use of energy and thus the impact of buildings on the environment. In a physical sense, a passive design approach is one that will use only locally available energy sources like radiation from the Sun, air movement from winds and temperature differences and utilise the natural flow paths of that energy to produce work. This work is mainly the heating, cooling and lighting of enclosed space and as such passive design systems will require very little maintenance and reduce a building’s energy consumption by minimizing or removing mechanical systems like pumps and fans used to control indoor temperature and lighting and consume a lot of energy.
Passive architecture design is required in order to reduce on the need for mechanical cooling and heating of indoor spaces. In turn this heating and cooling is required in order to achieve thermal comfort. Therefore thermal comfort can be regarded as the end requirement of passive architecture design together with energy efficiency while achieving that. Bs en iso 7730 defines thermal comfort as that condition of mind which expresses satisfaction with the thermal environment. That is to say the condition when someone is not feeling either too hot or too cold. The main factors affecting thermal comfort are temperature of the air, humidity, air movement, metabolic rate and clothing. Of these, air temperature (which is the main determinant), humidity (which affects evaporative cooling from the human skin) and air speed or movement (which accelerates evaporation) are all affected by general environmental factors and can therefore be controlled using passive architecture designs.
- passive design strategies achieving heat gain reduction in the first block of rooms at the Belum rainforest resort
On this block at the Belum rainforest resort, heat avoidance was given utmost importance as the block is extensively shaded and a plethora of heat avoidance strategies was used compared to the passive cooling strategies. The strategies include orientation of the building to its site, use of deep over hangs, use of mesh shading devices on windows, shading of walls and façade, use of banyan sticks to shade windows and use of vegetation for shading both windows and the facade
This block of rooms is oriented in such a way the longer façade that has the rooms and window openings faces the north-south direction with no windows on the east-west direction. This provides for a shaded in-door space during day time , in this set up, exposure to radiation is minimised as solar radiation is easily controlled by over hangs since the high angle of the sun in the sky in summer makes it easy to shade windows using this while daylighting is maximised reducing on the need for artificial lighting in the building. Also in this orientation the eastern and western sides that have no window openings are exposed to the low-angle summer sun in the morning and afternoon and hence there is less heat gain from these
This block of rooms uses a pitched gable to gable type of roof. The use of a pitched roof provided for deep over hangs on the longer facades. The overhangs
On the north and south-facing walls, control direct beam solar radiation. And hence reduce on the incident heat on the façade and the first floor windows. Overhangs are most efficient because being external shading devices, they intercept solar radiation before it has entered through the windows or is incident on the walls and thus even when energy is absorbed by them it is not trapped behind the glass. As the building does not exactly face north-south, the over hangs are of increased size. This was also done to effectively provide shade for both floors of the block.
Mesh shading on windows
This shading was extensively applied to all windows of this block of rooms. This mesh shading placed in front of windows is considered more efficient than the over hangs mainly because it is suitable and provides shade for the windows all through the year. Unlike the other shading devices, it does not require extensive calculation to get optimal results and does not depend on the angle of the sun. The Mesh also provides this shading while allowing for air movement and thus encourages cross ventilation. The meshes are made of coated metals as being part of external shading devices there is need for the material to be weather resistant. They also have an added advantage of being flexible to use and maintain.
Banyan sticks cladding
The south and north facing walls of this block are almost entirely made of windows to promote ventilation with minimised exposed wall. The entirety of the windows and exposed wall is clad in closely arranged banyan sticks that further enhance the shading to the windows in addition to the mesh shading provided. Like the other external shading devices it reduces on the incident heat on the windows and the walls. And also due to their distance from the window radiation energy absorbed by the banyan sticks is not re-radiated to the window or wall. They were also used as a base for vegetative shading. Being a form of vertical shading, they have been also used to shade the east and west facades of the block. The banyan sticks are treated to achieve weather resistance and prevent decay. They have a major disadvantage of reducing visibility and natural day light into the building
The façade of the block was also constructed in such a way that the exposed walls are perpendicular to the direction of the façade and as such are entirely shaded by adjacent walls. This design ensures that no external wall is directly exposed to the sun and as such do not absorb radiant heat.
This was achieved at this block of rooms by use of climbing plants that get support from the banyan sticks cladding. With the banyan sticks already positioned to provide shading, the plants are introduced so as to enhance the shade provided by the sticks. These plants provide the third and final layer of shading after the mesh shading and the banyan sticks cladding. They reduce solar radiation to as low as low as 20%.These together with the banyan sticks façade cladding also work as a climate shield, protecting the building from rain and wind drafts through the windows.
They also protect the buildings colour and the façade it’s self from intensive weather. Plants also have the added advantage of providing evapo-transpiration, where, as plants transpire and loose water to the atmosphere, the evaporation that takes places uses heat energy from the surrounding cooling it in return.
- Passive cooling strategies employed in the first block of rooms at the Belum rainforest resort.