With the rapid growth of the Chinese economy, increased
efficiency of energy use in China is an important element of a strategy
to achieve sustainable world development. It is projected that future
buildings in China will consume about one-third of the total energy.
The aim of this project is to identify new technologies and applications
of existing technologies that will significantly increase the efficiency
of new and renovated Chinese buildings. In addition, the strategies
for energy efficiency must be appealing to Chinese builders and
consumers, and they must be made aware of the advantages in using
the strategies. Our focus is on residential buildings in large Chinese
cities beginning with Beijing, Shanghai and Shenzhen.
The development of the Chinese economy encourages
the demand for higher living standard in China. At present air-conditioning
is a key symbol of improvement of living standards. In 1997 about
3.5 million air-conditioning units were sold. The air-conditioning
industry has increased 13 times since 1985. The infrastructure investment
in air-conditioning exceeds 25 billion Yuan ($3 billion U.S.). Energy
consumption by air conditioners in the summer has become a main
cause of severe electrical power shortage. The electricity consumed
by air conditioners in the basin of the Yangtze River is more than
1/3 of the total power supply during peak summer demand. If the
trend continues and all 1.2 billion Chinese live in a style similar
to Americans, the world's fossil energy will be more rapidly exhausted.
The trend of massive energy use in China has raised
global concerns. Fossil energy consumed by power plants and by building
heating plants results in an increase in CO2 and SO2
emissions. Green house gases such as CO2 lead to global
warming. The SO2 emissions in China bring acid rains
to the entire fast-east region. In addition, the Chlorofluorocarbons
(CFC) from the air-conditioning systems can cause further damage
to the ozone layer. Therefore, conservation of energy, protection
of environment, and improvement of indoor air quality and thermal
comfort are challenges we are facing.
Many old Chinese buildings can provide reasonable
comfort and indoor air quality without using air-conditioning systems.
A few years ago, in the countryside in China, the main objective
of Chinese home buildings was to protect occupants from severe climatic
conditions. The designs were simple and in harmony with nature.
Natural ventilation and/or thermal mass provided passive cooling
and additional heating could be made available when required. The
buildings often were built by the owner and occupant of the building.
This allowed a continuous improvement of these designs, based on
a close feedback between the occupants and builders.
Due to the development in the Chinese economy, new
building technologies allow builders to construct more comfortable
buildings. For example, the artificial control of the indoor environment
using air-conditioning makes it possible to build a building without
paying attention to the outdoor climate conditions. As a result,
most recent buildings are built without traditional technologies
but with mechanical systems. Although modern life will not accept
the comfort levels of the past, it is still possible to apply these
excellent traditional technologies to modern designs. Shading devices,
natural ventilation, passive and evaporative cooling, steep roofs,
passive heating, thermal walls, etc. are useful to improve thermal
comfort, reduce the energy demand and significantly protect the
On the other hand, the use of air-conditioning systems
may not improve the welfare of the occupants as assumed. More and
more occupants are not satisfied with their living environment.
The Chinese have realized the problem of sick building syndrome
due to poor indoor air quality and thermal environment. The main
problems in those new buildings associated with indoor air quality
- Many buildings do not have sufficient fresh
- New building materials used in China emit
too many volatile organic compounds.
- Air conditioning systems generate various
The thermal environment provided by air-conditioning
systems is normally of a constant temperature. Under a constant
temperature environment, the human body resistance to diseases has
been weakened sharply. The overall healthy level of the occupants
in air-conditioned environment is poorer. In addition, the occupants
can easily get heat shock when they enter the outdoor environment
in summer from an air-conditioned room. In 1996, so many people
had heat shock in Nanjing that the hospitals could not handle all
the patients. In the 1970s, the temperature recorded was much higher
than that in 1996 but not as many people had heat shock. Overwhelming
use of air-conditioning systems is an obvious factor to blame.
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