“Energy-efficient” buildings? Not always

New climate-controlled edifices in China are promoted as eco-friendly and desirable. But, writes Li Taige, researchers in Beijing have found that high-tech can mean high energy use – and no fresh air.

A friend of mine lives in Beijing Tiptop International Apartments, one of the city’s high-end residential complexes. One of the building’s features is a climate-control system that maintains a constant temperature and humidity.

But such comfort does not come cheap. He pays 8,000 yuan (about US$1,170) a month for his two-bedroom apartment — no small price.

The apartments are five years old and known for their use of energy-saving technology. According to the property developers, the building was China’s first “high-comfort, low-energy” project. Temperatures are kept at between 20° and 26° Celsius (68° and 78.8° Fahrenheit) without the need for individual air-conditioning units or radiators, and the ventilation system is said to provide health benefits. The project also claims to be “the first building in China to reach European energy-saving standards” — and to have “caused a sensation, with 1,300 media reports”.

The Tiptop is not the only Beijing building to use climate control as a selling point. Other examples include the Modern Group’s Moma buildings. The Grand Moma (Linked Hybrid) residences, Shangdi Moma and even the villa community of Forest Forever Moma all boast constantly controlled temperature and humidity.

For a long time I’d been a supporter of these buildings. After all, they save energy and still ensure a pleasant environment. However, after reading the 2008 Annual Report on Chinese Energy Efficiency, my opinion started to change.

Produced by Tsinghua University’s Building Energy Research Centre in Beijing, this report points out that if “energy-saving technology” is simply put in place without careful selection and management, energy use may not fall. In fact, it may increase substantially.

A residential building in Beijing is given as an example. A high-efficiency central air-conditioning system was installed to provide 24-hour climate control throughout the building. This was hailed as a fine example of energy saving. But in summer it uses eight times as much energy as traditional air-conditioning methods.

The report goes on to say that not only do these controlled environments fail to save energy, they also fail to be healthier, more comfortable or more convenient. A temperature of 26° is not the upper limit of comfort in the summer; it is the lower limit. A temperature of over 26° benefits health and reduces the illnesses that air-conditioning can cause. With natural ventilation, a temperature of 29° (84.2°) is most comfortable.

It seems there may be no benefit to the pursuit of constantly controlled environments.

Because the phenomenon of “energy-saving” buildings is not restricted to the residential sector, office complexes suffer the same problem. One office development in Beijing installed a number of solar water heaters. This is all very well, but the system used requires the water to circulate constantly. And the cost of running those pumps was almost as much as the cost of heating the water in the first place. This is hardly power saving.

A central government organisation refurbished its offices in 2003, replacing single-glazed windows with double-glazing for better insulation — but the majority of the new windows could not be opened. The individual air-conditioning units in each room also were replaced with multi-room units, or “quasi-central air-conditioning”. The result was that the building’s energy consumption rose by 50%, with energy used for air-conditioning increasing fourfold. Even so, this is less consumption than that of many high-end government offices. Imagine how much energy is being wasted in all of Beijing’s other government offices.

The report also points out that the numerous large-scale and energy-hungry public buildings – government offices, concert halls, museums, transportation hubs and so on – have become a way of demonstrating economic prowess. The refitting of existing public buildings, too, is causing large increases in energy use.

The new China Central Television (CCTV) headquarters in Beijing in Beijing could be called bizarre in design, and their appearance has earned them the nickname of “the giant pants”, but every time I walk past them I find myself wondering how much energy the building will use when it is fully operational.

Simply installing energy-saving technology without thinking about how it will actually be used is not a practice unique to Beijing. At a discussion with the news media organised by the Climate Change Journalists Club, Jiang Yi – a member of the Chinese Academy of Engineering (CAE) and professor at the Building Energy Research Centre – provided a number of examples from around China.

A solar energy firm in Wuxi in Jiangsu province employed a Dutch architect to design a 20,000-square-metre office building, using energy-efficient glass. However, the windows could not be opened, turning the building into a glass box that relies on a mechanised ventilation system. The building is equipped with solar panels, but the energy they supply is inadequate to power the ventilation system – hence a perfectly sound energy-saving mechanism has been wasted. The building is due to be completed this year, and may yet appear in the news media as another energy-efficient success.

At the end of last year, Yalong Bay in Hainan province started work on a huge central-cooling system. A modern refrigeration plant will deliver cold air to hotels in the area via a network of pipes – much as heating is delivered in the north of China. The project will cost 100 million yuan (US$14.5 million) and is Hainan’s first national-level energy-saving project. It is also said to be China’s largest central-cooling system. But Jiang has his doubts, suspecting that the project actually will increase energy consumption.

As the report makes clear, we can now create and maintain any environment we choose; we can do so in one of two ways: relying primarily on machinery or primarily on nature.

The “machinery-first” model uses artificial ventilation, air-conditioning and lighting to create the desired indoor environment. To do so on a global scale would require 30% more energy than is available – and it is not necessarily good for our health. For example, many “modern” buildings have few, if any, windows that can be opened, resulting in poor air quality and other problems.

A “nature-first” approach allows for ventilation via open windows and the use of natural light and shade, and when this is not adequate, supplementation with artificial means, such as heating. Climate control is adjusted in tandem with the environment.

So the researchers at Tsinghua hold that we should use that natural approach, improving living conditions without increasing power use. And this is the only option for real energy-saving buildings when we are faced with both scarce resources and huge environmental pressures.

I hope that my friend, and the rest of China, can realise the truth about China’s “energy-efficient” buildings.


Li Taige is a Beijing-based journalist. He obtained a master’s degree in engineering from Sichuan University in 1997 and was a Knight Science Journalism Fellow at the Massachusetts Institute of Technology (MIT) in 2003-04.

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