Sustainable construction mitigates climate change

Increasing pressure for rich economies to meet their global commitments to lower carbon emissions by 50 percent from 1990 levels by 2020 have pushed many governments to provide huge fund assistance and tax incentives to help investors develop green-technology solutions, including sustainable and low-carbon construction.

Sustainable construction, or green-technology design, are terms used as economic activity to continue the boost in global infrastructure but bearing in mind the need to lower carbon emissions to mitigate the harsh impact of climate change.

The British government said the green economy is valued at $4.5 trillion and currently accounts for 900,000 jobs in the United Kingdom. Britain identified the Philippines as one of the emerging powers of Asia that will play a crucial role in delivering global economic growth in the 21st century.

PPP attracting British companies on green tech
The Philippines’s current intention to boost infrastructure and public services through the public-private partnership (PPP) models have been attracting many British companies to engage in consultancy and engineering services on green-technology solutions.

Dr. Andrew Hinton, business specialist of the United Kingdom Trade and Investment (UKTI), said the UK is well placed to lead the global shift to a low-carbon future and seize opportunities across all sectors of the global economy.

“As an emerging international hub for low-carbon expertise and innovation, the UK is helping global businesses to shift to a low-carbon future through smarter, more sustainable low carbon, green design and technology-based solutions,” said Hinton in his speech at the recent seminar on Green Designs and Technologies hosted by the UK embassy in Manila.

He said British companies are keen to be involved in the Philippine government’s PPP projects, particularly on airport, rail, roads and power projects.

BREEAM, Berde rating systems
Infrastructures are considered green based on the rating system first developed in the UK called the British Research Establishment Energy Assessment Method (BREEAM). The rating system is now the world’s leading design and assessment methods for sustainable buildings.

The Philippine Green Building Council (PhilGBC) has developed the Building for Ecologically Responsive Design Excellence—which acronym, Berde, aptly means green—as the country’s own green-rating system patterned after Britain’s BREEAM. It encourages developers to adhere to green technologies as part of the solutions to the harsh impact of climate change.

Ramon Rufino of the PhilGBC said the Philippine government needs to implement tax breaks or incentives to encourage more stakeholders in low-carbon and sustainable construction. Tax incentives and access to huge fund assistance have encouraged British investors to develop research technology on low carbon and sustainable construction, a similar government action that Philippine developers also want to be implemented in the country.

Rufino also said local developers also face challenges of not finding enough consultants or experts on green technology. He also raised concern that there are not enough green materials and supplies available in the local market.

Among the country’s leading green architect, Carmelito Tatlonghari, said it is only Quezon City that implements tax breaks of 20 percent on real estate for developers of green-technology designs. He said the Green Architects Movement (GAM) in the Philippines are working with the Climate Change Commission, an attached body of the Executive department to implement a mandatory tax break for all cities and municipalities to encourage developers of commercial, industrial, residential and even roads to use low-carbon and sustainable-technology designs.

But Hinton believes that while governments have yet to consider tax incentives and other measures to encourage investments in low-carbon and sustainable construction, the private-sector developers are.

Sustainable design
One of Britain’s leading green-technology company, RED Asia defines sustainable design as smart use of energy, water and construction materials to be successful in comfort and without being unnecessarily harmful with the environment while adhering to the client’s needs.

Ed Whitney, director for RED Asia Inc., said sustainable designs seek to maximize the external natural conditions, such as lighting, ventilation and water supply. He said RED Asia base its designs around the layout of buildings to maximize the positive effect of external conditions and shading to minimize solar gains; optimize natural daylight and natural ventilation; use of ground effect for passive evaporation to provide natural cooling; water conservation/water harvesting/water recycling. Whitney said developers also need to think of different types of renewable-energy sources as best fit for each building.

Passive building features
There are key components to passive building features that include fabric and green roofs. Green roofs, according to Whitney, are growing in popularity throughout the world due to range of benefits that include:

• Reduction in building cooling and heating energy use
• Reduction of storm-water runoff and contribution to sustainable drainage
• Promotion of biodiversity
• Can increase lifetime of a roof by protecting the waterproof membrane
• Certain types of green roof in a hotel application can be used as outdoor garden space providing usage for clients or even as a source of herbs for the hotel kitchen.
• Green roofs normally require irrigation. The degree of maintenance required is dependent upon the type of green roof. It is possible to install a green roof on an incline of up to 40 degrees.

Passive building features, such as north-light windows, can provide good day lighting without creating solar heat for the structure. He said that many commercial and residential structures with huge lighting requirement should use this passive building feature as artificial lighting typically contributes around 30 percent of carbon emissions in a typical building. RED Asia also suggests the use of light pipes as source of passive light. Light pipes are highly polished metal tubes, with a polycarbonate dome at the top and a light diffuser at the bottom.

Natural ventilation
Sustainable construction also promotes natural ventilation, which is driven by natural forces of wind and temperature to avoid heavy use of air-conditioning facilities. Green developers believe in the benefits of fresh air to provide oxygen and dilute body odors.

The natural-ventilation approach, according to Whitney, aims to give developers a relief from the heavy use of air conditioning to cool modern buildings, which result in high solar-heat gains, poor natural daylight and use of many energy intensive appliances.

The rapid increase in the use of green-energy technologies is also driven by the high cost of electricity in the Philippines, which is among the five countries in the world with the highest cost of electricity.

Energy-efficient design
Red Asia suggests to clients to select the most energy-efficient designs appropriate to the type of site and building equipment to minimize power consumption.

The use of available heat used in the system through the combined heat and power (CHP) is widely suitable for hotel and leisure facilities due to the intense demand for heat. CHP can provide dedicated on-site electricity generation at enhanced efficiency and reliability compared to a grid-connected supply.

An installed CHP system has a payback yield of 10 years and the use of the equipment is intended for the following: heat recovery devices; variable speed drives; selection of most efficient plant available; free cooling; enhanced control systems; selection of efficient lighting technology;  effective lighting controls; proper metering and logging of services; and low/zero carbon technologies.

Recycling water
As global water supply is fast becoming more scarce and an expensive commodity, more developers are integrating in the sustainable-construction designs the efficient use and recycling of water.

The sustainable use of water in low-carbon designs include systems for water conservation using waterless urinals, dual flush WCs, low flow shower heads and flow controllers on basins, rainwater harvesting using water collected from roofs; gray water recycling using water from basins and showers; and proper metering and logging of water use to analyze overconsumption on the site.

Gray water recycling is also fast becoming more appropriate for luxury hotels that require the availability of large quantities of fresh water. Red Asia explained that gray water recycling is the reclamation, treatment and re-supply of water from sources, such as wash basins, baths and showers.

In a hotel context, there is opportunity to reclaim a significant volume of water and recycle it for toilet flushing, irrigation, car washing and possibly as a resource for water-intensive operations, such as laundry facilities. The company believes that gray-water systems can be configured to suit the building, with storage provided at any level and a main water connection is normally provided to meet surplus demand.

It added that the current typical benchmark for water consumption for a four- or five-star hotel with swimming pool is 350 liters per day per guest of which gray-water recycling could potentially supply approximately 30 percent of this figure.

Recognizing natural assets
Recognizing the natural assets to the site of the infrastructure is crucial in determining the sustainable construction design for each building. An example is the sea, where there could be an opportunity to reduce energy consumption for building and ventilation cooling by harnessing the cooling capacity of seawater.

“The key issue that will bear upon the practicability of using seawater cooling for the hotel is the ability of the inlet pipe to be located at sufficient depth to provide cool water. If appropriate space cooling systems are used, seawater at 12 degrees Celsius can provide sufficient cooling without requiring chillers to operate,” said Whitney.

The rapid growth and investor interests in low-carbon and sustainable construction in the Philippines is driven by the fact that the country is one of the world’s most vulnerable countries in Southeast Asia to climate change due to its long coastlines, huge population, large economic activity in coastal areas and heavy reliance on agriculture and natural resources.

The country experiences more than 20 typhoons every year, mostly harsh ones as well as other disasters, such as earthquakes and floods. The extent of destruction is pushing the government to implement comprehensive measures to promote sustainable development.

The Asian Development Bank found Southeast Asia as twice vulnerable to climate change compared to world average. It warned that the region could lose 6 percent to 7 percent of gross domestic product by 2100, if nonmarket impacts and catastrophic risks are also taken into account.

Source : Business Mirror

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