Sunday, June 23, 2013

Solar House's energy saving solution

By Elizabeth Hsu and Luke Sabatier, CNA staff writers
In a 100-year-old house being renovated on an old street in Daxi in Taoyuan County, volunteers with little construction experience are working with materials not normally seen in building upgrades -- mud and straw.
Those materials, used to make the walls that will help insulate the Japanese colonial era structure, are among the simple tools that foreman Wei Ren-jen is relying on to make the house livable without air conditioning or excessive lighting, even though it is sandwiched between two much higher concrete buildings.
The project is Wei's latest attempt to showcase the importance of insulation as an essential energy saver in green buildings in sub-tropical Taiwan while creating a comfortable interior environment, particularly topical at a time when the country is struggling to come to terms its future energy needs.
Taiwan currently gets 20 percent of its electricity from three nuclear power plants, but they are scheduled to be decommissioned by 2025.
Opposition to another nearly completed nuclear power plant has risen since the Fukushima Daiichi Nuclear Power Plant's meltdown in Japan in March 2011, making nuclear power an uncertain option.
Much of Taiwan's remaining electricity is generated by thermal plants that produce large amounts of carbon emissions and, in the case of coal-fired plants, small particulates.
While Wei argues that Taiwan needs to have a more honest debate on what the country's future energy mix looks like, he, along with many other green building advocates, feel that the best solution to the energy dilemma is energy conservation.
"The best alternative energy is not using energy," he says.
Buildings in Taiwan account for 34 percent of the country's total electricity consumption, according to the Bureau of Energy, and Wei sees a genuine opportunity there to reduce electricity waste.
"It really bothers me when I see the new buildings being sold in Taiwan, because architects are really not paying attention to the issue," says Wei, chief executive of the HAND Initiative, a nonprofit Taiwan-based organization devoted to the promotion of a lifestyle in tune with nature.
"Today's buildings are like sieves. They simply let electricity leak out."
Thus the need for tight building specifications, such as airtight window frames, double-layer low-emission glass, and of course insulation, which most people in Taiwan intuitively associate with cold rather than warm climates.
The concept has already been tested in HAND's Solar Library in Taipei's Youth Park. The unmanned public library, designed and built by architects Chang Ching-hwa and Kuo Ying-chao and supervised by Wei, is based on energy-saving ideas long advocated in Germany that Wei and HAND founder Hu Shiang-ling now espouse and strict energy efficiency standards adopted in Germany in 2007.
Drawing on Hu's book "Solar House," published in Taipei in 2006, the Solar Library and now the Daxi renovation project actually have little to do with solar power. Instead, in Hu's words, these "solar houses" are like integrated energy-consuming systems that use local natural resources on the basis of careful scientific calculations.
Wei explained that every material has its "absolute function" due to its unique character. Wood, for example, has very low thermal conductivity, which is why thick boards consisting of wood chips were used to insulate the solar library and keep the building from turning into an oven.
Opened in late October 2011, the library, a two-story building with about 660 square meters of floor space, has consumed about 74 kWh per square meter over the past year (a measure known as EUI or energy use intensity), about 36 percent less energy than the average 116 kWh per square meter per year consumed by municipal and national libraries around Taiwan, according to HAND and government data.
The solar library's indoor temperature rarely exceeds 28 degrees Celsius, even at the height of summer. If many people are in the building, the air conditioning is turned on and has an almost immediate cooling effect, according to HAND data.
"Thanks to its airtight house shell, the temperature drops quickly when the air conditioning is turned on, also saving power," Wei said.
Of course, building a new library from scratch or tearing down an old house in Daxi and rebuilding it offers little solace to Taipei residents stuck in what seem like concrete ovens during the summer, right?
"No. Concrete has good thermal conductivity, but because of its mass, if you insulate it, it's actually a great temperature stabilizer," Wei says. "It won't create huge indoor temperature swings. In the summer, it won't heat up to really high temperatures and in the winter, it will maintain some of its heat."
Under the concepts Wei advocates, many houses and buildings in Taiwan do not have to be torn down to allow residents to live comfortably while saving energy, he contends. "All you have to do is change the house shells."
"Instead of encouraging new house construction, the government should encourage banks to lend people money to fix old ones. This will improve both the outer appearance of a building and the interior living spaces," Wei said.
Chang Ching-hwa, the architect behind the solar library who also designed the energy efficient Beitou Library, commended Wei for his use of a scientific approach to minimizing buildings' energy consumption.
But she acknowledged that since designing the solar library, there had been few other opportunities to put the insulation concept into practice, even if green building is becoming more mainstream among clients.
"There are different ways to achieve the goal of energy saving and reducing carbon emissions. Wei's idea is one of them, but different strategies can be applied in different areas," she says.
But as much as hikes in electricity prices are extremely unpopular, both among businesses and consumers, Chang feels they may be necessary for green building concepts to be widely embraced.
She said Germany can adopt a zero nuclear power policy because it has high electricity rates. But Taiwan's electricity prices are too cheap to induce people to save energy or demand more energy-saving structures.
In the meantime, Wei's workers and volunteers continue to mix mud dredged from nearby Shihmen Reservoir with shredded husks from rice fields and put them into molds to make the temperature-stabilizing bricks that form the walls of his new project.
"It's actually easy to achieve the goal of energy saving without compromising the comfort of a living space," Wei says. "The Solar Library and projects like this convey a clear message to people in Taiwan -- there is a solution."