BY ARCH. AMADO DE JESUS
Providing homes and buildings with natural ventilation in a crowded city like Metro Manila is both a challenging and daunting undertaking. Not only are buildings packed so closely, there are few green spaces and most areas are covered with asphalt and concrete pavement and roads, thus contributing to what is known as the urban heat island or UHI phenomenon. Urban heat island is what results from cities that have very little greenery and very many concrete surfaces. The city will have a much higher temperature than that of the surrounding suburbs and countryside. Figuratively, it forms an “island” of warmer land, while being surrounded by cooler land.
Since the Philippines is a hot humid country, it seems obvious that the only way to provide comfort for occupants is through air conditioning and electric fans. Considering that about 60 percent of the energy in a building goes to air-conditioning, being dependent on air-conditioning translates into high electricity bills.
So back to the question: how do you provide natural ventilation for homes and buildings in very crowded urban areas?
One effective and simple strategy is to utilize what is known as the stack ventilation. Stack ventilation takes advantage of the temperature difference and pressure differentials of the air. Warm air becomes less dense and rises while the cooler air passing through the lower openings replaces the air that has risen.
Stack ventilation requires height differences as in lofts and atriums. For many structures one area where stack ventilation can take effect is in the stairwell or large lofty spaces.
To achieve natural ventilation, the maximum ratio of floor depth to ceiling height must be considered and the heat gains to be dissipated which determine the total area of the opening. The stack ventila
tion is part of a set of best-practice options being introduced by EDGE which stands for “Excellence in Design for Greater Efficiencies.”
EDGE is a building design tool, a certification system, and a global green standard for nearly 100 emerging market countries. The program is for anyone interested in the design of green buildings, whether an architect, engineer, developer or building owner.
EDGE facilitates technical solutions at the early design stage to reduce operational costs and environmental impact. Depending on the user’s information inputs and green strategies chosen, EDGE projects operational savings and reduced carbon emissions.
The EDGE software includes modules for homes, hotels, offices, hospitals and retail with building-specific user guides accompanying them.
EDGE is an innovation of IFC, a member of the World Bank Group.
A global green standard
EDGE offers a set of technical measures that when selected will reduce a building’s operational and embodied energy and water use. To achieve the EDGE standard and qualify for certification, a building must achieve a 20-percent reduction in energy, water and materials.
EDGE aligns the interests of market players such as financial institutions, developers, government regulators and homeowners to create a groundswell of engagement that catalyzes resource-efficient building growth.
EDGE aims to convert 20 percent of new construction from conventional to green in priority markets within the next seven years. This effort is supported by other certification service providers in Costa Rica, India, Indonesia, South Africa and Vietnam.
IFC is the largest global development institution focused on the private sector in emerging countries. Working with more than 2,000 businesses worldwide, it uses its capital, expertise and influence to create opportunity where it’s needed most. Standing between the public and private sectors, IFC brings market-based solutions to respond to the challenge of creating low-carbon economic growth.
The Philippine Green Building Initiative or PGBI is the sole certifying body for EDGE projects in the country. For information, visit www.greenbuildingph.wordpress.com. There will be a presentation to developers on July 20 at 1:30-3:00 p.m. at the IFC Office, One Global Place corner 5th and 25th streets, Bonifacio Global City. Call up Yvette at tel. no. 0917-8737711 for details.
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