Abstract
There has been an increasing demand in energy consumption of structures especially air-conditioning system and there is a need/solution on how to minimize/reduce the consumption of energy. In the recent years we witnessed and experiencing energy crisis, especially during summer seasons because of demand usage of air-conditioning systems. With the continuous increasing demand of energy our surrounding experiencing environmental pollution like global warming and ozone layer depletion. Experts like architects and engineers practice the application of Passive Cooling System or Techniques into the buildings.
Passive cooling use non-mechanical methods to maintain a comfortable indoor temperature and preventing heat from entering the interior spaces of a building. Passive cooling techniques are usually applied on commercial buildings like malls because it is the main energy consumers. This study focuses on how to conserve energy and how will a design will achieve energy efficiency and save the next generation. Keywords: Energy Consumption, Passive Cooling, Energy Consumer, Energy Efficiency
BACKGROUND OF THE STUDY
A recent study Kamal (2012), indicates that last two decades we witnessed a severe energy crisis in developing countries especially during summer season primarily due to cooling load requirements of buildings (see graph attachment).
The energy consumption in buildings is quite high and is expected to further increasing because of improving standard of life and increasing world population. Air-conditioning use has increasingly penetrated the market and greatly contributes in the energy consumption. Passive cooling is a means of preventing heat from entering the interior spaces of a building and for removing heat after it has entered such spaces. Passive cooling uses solar energy or other natural cooling sources, like evaporating cooling, passive ventilation to control indoor climates.
The exact application of these strategies and specific design of the systems depends on the prevailing climatic conditions of a location. These techniques can be applied on provinces like Bulacan because this location is good in air/wind movement and it can possess natural ventilation. Passive Cooling engages structures like wind catcher and is sometimes used in combination with evaporative cooling to further maximize cooling potential. Historically there have been two strategies used to reduce energy consumption in times of fuel shortage: ‘energy conservation’ and ‘energy efficiency’. These terms have often been used interchangeably in policy discussions but they do have very different meanings Herring (1996). Energy conservation is generally considered to mean reduced energy consumption through lower quality of energy services, for example: lower home heating temperatures; vehicle speed limits; capacity or consumption limits for appliances, often set by standards. Often it means doing with less, or even without, to save money or energy. It is strongly influenced by regulation, consumer behavior and lifestyle changes.
RELATED LITERATURE
“Sustainable design is more a philosophy of building than a building style. Most energy Efficiency and other green technologies are essentially “invisible”, that is they can be blended into any architectural style. While green features can be highlighted to demonstrate a building is connection to the environment, they do not have to dominate the design.” –According to Barret (1999)
This statement gives the idea of design elements of a green building that fall into broad categories, energy saving architectural features and an energy conserving building. This approach may change the higher prices of consuming electrical energy to achieve large savings for the whole. This will result to lower operating cost. A recent study Kamal (2012), explains how ‘passive’ solar design involves the use of natural processes for heating or cooling to achieve balanced interior conditions. The flow of energy in passive design is by natural means: radiation, conduction, or convection without using any electrical device. Maintaining a comfortable environment within a building in a hot climate relies on reducing the rate of heat gains into the building and encouraging the removal of excess heat from the building. To prevent heat from entering into the building or to remove once it has entered is the underlying principle for accomplishing cooling in passive cooling concepts.
Shading by overhangs, louvers and awnings
Well-designed sun control and shading devices, either as parts of a building or separately placed from a building facade, can dramatically reduce building peak heat gain and cooling requirements and improve the natural lighting quality of building interiors. The design of effective shading devices will depend on the solar orientation of a particular building facade. For example, simple fixed overhangs are very effective at shading south-facing windows in the summer when sun angles are high. Kamal (2012)
Shading of roof
Shading the roof is a very important method of reducing heat gain. Roofs can be shaded by providing roof cover of concrete or plants or canvas or earthen pots etc. Shading provided by external means should not interfere with night-time cooling. A cover over the roof, made of concrete or galvanized iron sheets, provides protection from direct radiation. Disadvantage of this system is that it does not permit escaping of heat to the sky at night-time. Kamal (2012)
Shading by trees and vegetation
Proper Landscaping can be one of the important factors for energy conservation in buildings. Vegetation and trees in particular, very effectively shade and reduce heat gain. Trees can be used with advantage to shade roof, walls and windows. Shading and evapotranspiration (the process by which a plant actively release water vapor) from trees can reduce surrounding air temperatures as much as 5°C. Different types of plants (trees, shrubs, vines) can be selected on the basis of their growth habit (tall, low, dense, light permeable) to provide the desired degree of shading for various window orientations and situations. Kamal (2012) A recent study Edwards (1996), use of natural ventilation can result in both capital cost and energy savings and in addition, it is also desirable to minimize the requirement of mechanical ventilation and air-conditioning systems in order to ensure a ‘healthy’ building. Enclosed central courtyards or atria can be used to save energy by using the space as a means o bring fresh air into the building and to provide natural preheat.
A recent study Bajardi (2011), demonstrate the ‘passive retrofitting’ strategies for the school buildings in the Mediterranean area. The architect showed the case studies of the ITACA department on the field. The “passive retrofitting” concerns energy efficiency and it consists in reducing the energy demand that will then be covered by “‘active” integrated systems which are powered, in so far as possible, by renewable sources. The passive strategy also affects the building morphology and the building envelope technology, offering an important occasion for the upgrading of the appearance of building structures.
The so-called ‘Mediterranean’ climate is a local variant of the temperate climatic zone which extends between the cold climatic zone and subtropical zone around the Mediterranean sea. The main characteristics of these types of climate are the presence of a dry and hot season during the summer months and a season which is moderately cold and humid during the winter season. Improving the energy performance of a building located in these climatic conditions encounters contrasting requirements (summer/winter) that must be suitably reconciled in order establish the most convenient point of optimization.
Ventilation provides air circulation, and it moves the cool air in at night. Casement or awning windows, which open on side or top hinges, can be installed to take advantage of the prevailing direction of the breezes of the location. Clerestory windows can be opened to let out the hot air at the top of the building. Nowadays, I’ve observe that malls are utilize by large openings to maximize the use of natural light,providing clerestory or vented skylights, subdivided stalls/villages (like Tiendesitas), with a sky gardens or landscapes inside the structures. They applied this design because this practice is achieving an energy efficient structure by natural cooling and cooling through landscapes. This application can be seen on Gateway Mall (Atrium Garden), Ayala Mall, Tiendesitas.
CONCEPTUAL FRAMEWORK
Nowadays we should practice to design structure with valuable contribution to the environment. Energy efficiency will contribute a lot to the environment and save the future. Passive Cooling techniques can reduce the peak cooling loads to the building, thus reduce the size of the air conditioning equipment. Passive cooling methods such as placing trees, landscapes help to control air in the area of the structure and slow heat transfer into the building (this indicates the heat conduction, heat transfer and thermal radiation (heat flow of the sun). Study the air movement of the area. Some are latest heating, air conditioning and ventilation technology such as fan-assisted cooling strategies, clerestories or skylights that allow adequate internal flow, natural ventilation by application of large openings & double glaze windows/glass.
The newly built commercial building which is a mall in San Jose Delmonte, Bulacan, the Starmall, the first big mall in the city with a refreshing, relaxing atmosphere and an environment that is close to nature. Shoppers love Starmall’s spacious and environment-friendly design that refreshes and energizes. Trees and greenery surround the mall, greeting you everywhere you look. Proper Landscaping can be one of the important factors for energy conservation in buildings. Vegetation and trees in particular, very effectively shade and reduce heat gain. Trees can be used with advantage to shade roof, walls and windows.
STATEMENT OF THE PROBLEM
GENERAL:
With the increasing demand of energy consumption, how can the structure be energy efficient by passive cooling?
SPECIFIC:
* How to provide natural cooling that is effective for different spaces inside and out of the building? * Does technological innovation to improve the efficiency of energy using products and systems lead to lower energy consumption and hence reduced environmental impacts? * What are the possible building materials or passive cooling techniques that can be applied to possess an energy efficient building?
METHODOLOGY
The research design that I think will contribute a lot is by Interpretive Historical Research which deals on how buildings are being ventilated within past years and what are the issues from the past, conducting a historical research about buildings that are energy efficient and possess the application of Passive Cooling Techniques. The most efficient is Case Study Research which contain one or more approaches concerning on Passive Cooling. Many studies will contribute a lot in sourcing ideas. An example is conducting a research on foreign and local studies. These case studies will give me many ideas on building cooling, how to remove unwanted heat from the sun to the structure and to know the approaches that are applicable and not.
Another is Qualitative Research, which depends on my own ideas about what are helpful materials that makes a building energy efficient. Brainstorming is very effective on dealing solutions and by sharing your own opinions will contribute to the advancement of inventions and more likely to know your own findings. Some of the basic and effective method is conducting an interview to an architect or engineer or even a student or expert. This interview will help me to understand more information about Passive Cooling. With their expertise, knowledge and experience you can gain new issues, phenomenon, and situations that will in your study. Questions that are being asked are the specific. The topics are on Passive Cooling through Solar Shading, Shading by trees and vegetation, Insulation, Induced ventilation techniques, Evaporative Cooling. The opinions of the interviewee will contribute a lot in collecting data and information about energy efficient structure.
REFERENCES
Brizioli, C.(2011) Passive retrofitting strategies for school buildings in the Mediterranean area. Retrieved from http://teenergy.commpla.com/index/brochure/02_PASSIVE_COOLING.pdf
Edwards, B. (1996) Towards Sustainable Design (European Directives & Building Design) Oxford. Butterworth-Heinemann Ltd. Page 68 Herring, H. & Roy, R. (2007). Technological innovation, energy efficient design and the rebound effect. Technovation. Retrieved from http://dx.doi.org/doi:10.1016/j.technovation.2006.11.004
Kamal, M. A.(2012) An Overview of Passive Cooling Techniques in Buildings. Acta Technical Napocensis. Retrived from http://constructii.utcluj.ro/ActaCivilEng
Stitt, F. (1999) Ecological Design Handbook. New York. McGraw – Hill Book Co., Inc. Page5
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