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FEATURE: New library offers 'green' inspiration in a simple box

2011/10/31 19:27:56

Building a nearly airtight box-like structure in the middle of sweltering Taipei and keeping the air conditioning off may sound like a recipe for disaster -- an oven waiting to bake those intrepid enough to step inside.

But the two-story Taipei library engineering consultant Hu Shiang-ling has cooked up with the help of German building standards and forward thinking architects could redefine how buildings are designed in Taiwan in the future to reduce energy consumption.

Inspired by Hu, who studied energy policy and practices in green-passionate Germany for many years, Leo Cheng, the late founder of Taiwan's biggest maker of solar cells Motech Industries Inc., asked Hu and her husband Wei Ren-jeng in 2006 to build an energy-saving structure based on her vision to serve as a model for the future.

The result is the Solar Library and Energy-Optimized House (Solar Leo House), inaugurated as a branch of the Taipei City Library in the Taipei Youth Park on Oct. 29.

It is being touted as Taiwan's first "solar house," an increasingly popular form of architecture in Germany that puts a priority on renewable energy and energy-saving strategies.

"A solar house is like an integrated energy-using system that uses local natural resources, actively using solar power and passively reducing energy consumption," said Hu in her book, "Solar House -- Made in Germany," published in Taiwan in 2006.

The box-like house in the Youth Park, which is surrounded by old communities, stands in sharp contrast to its aging neighbors with its sleek, modern appearance and solar panels covering part of its roof and canopy.

At present, the panels have an installed capacity of 3.6 kWp, but more will be added over time to reach a capacity of 60 kWp. Hu and Wei estimate the building will contribute to the power grid up to 90 percent of the amount of electricity it consumes.

"But the solar panels are really not at the center of what this building is about," says Wei, who serves as executive secretary of the HAND Initiative e.V. founded by Hu in 2003 to promote a lifestyle in tune with nature.

The library, which is Hu's brainchild and supported by HAND's comprehensive energy-saving plan, is built on the principle of "form following function."

Absolute rules based on strict German energy-saving standards imposed in 2007 are used to define function rather than the more expansive categories outlined under Taiwan's EEWH green building standard.

Under the EEWH, buildings are judged on nine indicators in four broad categories -- ecology, energy saving, waste reduction and health. But Wei said the new library has only one focus -- how to use energy in the most efficient way to keep the building's interior a comfortable 18-25 degrees Celsius.

"Every material used in the house has its absolute function, and our role is to select proper, sustainable and renewable materials to enable the house to save energy and allow people to live comfortably," Wei said.

The key, Wei explained, is to create a "proper house shell" -- in effect a shell that covers the reinforced concrete structure -- so that energy can be well preserved and efficiently used.

That's why the roof of the new solar library is covered with a 30-centimeter layer of insulation composed of a less dense inner layer of wood-chip fibers and an outer layer of higher density wood-chip fiberboards.

A 10-cm layer of the higher density fiberboard also covers the library's exterior walls.

The wood-based material, Wei said, has the lowest thermal conductivity of any insulator, keeping the heat out even during the hottest months.

Hermetic wooden window frames (again with low thermal conductivity) and double-layer low emission glass also form a key part of the library's insulated shell.

Germany requires all new buildings to use glass windows with a thermal conductivity (or U-value) of below 1.1 Watt per square meter kelvin (W/m2K) because "windows can be responsible for the loss of 20-25 percent of the building's total energy," Wei said.

The U-value of normal single glass is around 5.8 W/m2K, but the solar library's window averages 1.2-1.55 W/m2K, well within the German standard in 2007. The efficient glass means the French windows on the library's southern face will allow the building to bathe in sunlight without letting in too much heat.

This multifaceted shell, which Wei describes as a "functional cloth able to keep the house warm in winter and cool in summer," offers considerable promise in saving power.

"As long as we build the shells right, the air conditioning system in a solar house will consume only one-tenth the energy of a normal house in the same circumstances and environment," Wei asserts, citing German experience.

But how effective will the shell -- which Wei said costs about 14-20 percent of a building's construction costs (it was about 16 percent for the solar library) -- be in Taipei's sometimes oppressive heat and humidity?

Wei acknowledged that it will be a year before real numbers for EUI (energy use intensity) and other measures of energy use will be known, but he said that data kept for temperatures inside the building this past June appeared promising.

When the mercury was consistently hitting in the mid-30s during the day, indoor temperatures stayed around 25-26 degrees even without the use of air-conditioning or the library's heat recovery ventilator, which turns over the air in the library when its windows are closed.

"It's too early to talk about energy numbers right now. But there is one number that the average person can relate to. For two months in June and July, this 200-ping (660 square meter) library had an electricity bill of only NT$600 (US$20)," Wei said.

Though Hu provided the inspiration for the library, she turned to Bio Architecture Formosana architects Chang Ching-hwa and Kuo Ying-chao to realize the vision. Chang and Kuo designed the Taipei Beitou Library, the first building in Taiwan to earn the highest "Diamond" certification under the EEWH standard, as well as the three centerpiece pavilions at the Taipei Flora Expo.

"Compared with the Beitou Library and previous green building projects, the Youth Park Library uses even more advanced energy saving technology. The (Youth Park) library uses the most natural materials to conserve energy. So the whole library basically is built from green building materials," Chang said.

Both Hu, who is the chief executive of HAND, and Wei hope the Solar Leo House will spark a "silent revolution in the architecture business" that inspires local companies to produce construction materials that are green and energy efficient, including pursuing sustainable forestry in Taiwan to supply the wood insulation materials that had to be imported from Germany for the library project.

And that ultimately is the legacy Leo Cheng, who died of liver cancer in March 2008, hoped to leave behind -- as a platform to promote energy-saving concepts and technologies applied to the library.

"We see this more as a platform to promote discussion of efficient, eco-friendly and economic ways to save energy," said Wei, who stressed that the "solar house" concept could be copied anywhere in any form because it was not the appearance that mattered but the idea and spirit behind it.

"Let saving energy start with building and housing," Hu said. "We hope people will eventually know that using a small amount of energy can create a very comfortable living space." By Elizabeth Hsu and Luke Sabatier CNA staff writers