Cool buildings lead to green city
Cool buildings lead to green city
By Tri Harso Karyono
JAKARTA (JP): Economic growth has brought higher living standards, but has also had a negative impact in Indonesia. Cities were developed, infrastructure laid, high-rise buildings erected, but all this is being paid for by devastating the country's energy resources.
Because cities are being developed along western models, particularly American designs, there is a massive waste of energy.
A 1993 study done by the writer found that nine times more energy was used to cool each square meter in selected air- conditioned office buildings than in one naturally ventilated building.
It was also found that the comfort range for office workers was between 23.5 degrees and 29.9 degrees Celsius, which is wider and higher than the American standard of between 22.5 degrees and 25.4 degrees C. Indonesian building engineers use the American standard.
The Indonesian comfort figures are close to Jakarta's average outdoor temperature of between 23 degrees and 33 degrees C. There is therefore much potential for engineers to manipulate a building's indoor temperature to be within the comfort range without installing any mechanical means. Even if mechanical means are used, the amount of energy used for cooling could be lower if the building is designed correctly.
The city has more than 450 high-rise buildings and about half were office buildings.
Conserving energy requires new designs, open spaces and gardens because naturally ventilated buildings must be surrounded by open space. A city designed in accordance to the climate would have a unique shape.
A study of the radiant heat above different surface coverings revealed that air temperature above the concrete surfaces was significantly higher than above the grass. In Jakarta, this makes walking a short distance a chore because grassy areas have been concreted, the trees cut down and any open areas built upon. This makes the city even more claustrophobic.
The problem stems from Indonesian architects and urban designers trained abroad copying western ideas without proper interpretation or selection. Designers who have never been abroad, also mindlessly imitate the designs they see in films and magazines.
Concreting a square and planting a few trees is only necessary for people in cold or temperate climates. It allows the sun's radiation to warm the air above the ground. Copying this in tropical Indonesia is a huge mistake and could lead to disaster.
As a result of copying the West, most of Jakarta's buildings are simple steel column boxes covered by glass walls. Most of the new buildings, no doubt, are air conditioned. The climate is hardly considered in the design, causing huge amounts of energy to be wasted in cooling the massive greenhouses.
The naturally ventilated former Ministry of Religious Affairs building on Jl. Thamrin consumed one-twelfth of the energy used by the air-conditioned Agency for the Assessment and Application of Technology next door. On average, the former Ministry of Religious building consumed one-ninth of the energy the air- conditioned buildings of the Bank Central Asia, the Ministry of Education and Culture, the Indonesian Institute of Sciences and the Widjojo Center did.
The massive energy loss in air-conditioned buildings illustrates the problem of blindly copying western designs. Many buildings are designed with air conditioning just for prestige. The climate is almost ignored, causing the massive consumption of fossil fuels and, in turn, air pollution.
A city's identity should be based on its climate, culture and economy. Considering the local climate in energy conservation is crucial.
Trees must be planted within Jakarta to absorb the sun's radiant heat and shade roads and other concrete spaces. Grass is the ideal ground covering. Shaded sidewalks will encourage people to walk short and medium distances, decreasing the number of cars and therefore pollution. Tree-lined roads would keep vehicle passengers cool without the need for air conditioning.
By conserving energy, Indonesian cities will be greener not grayer.
The writer is an architect currently studying for his Ph.D in architecture in the United Kingdom.