Environmental Engineering Reference
In-Depth Information
logies. With these measures, Switzerland achieved a 50% energy savings in com-
mercial buildings over a 20-year period.
Developing countries face the problem of a huge housing deficiency, so the op-
portunities exist in improvements to building construction methods. Experience
shows that the cost of producing more-efficient buildings is not much higher than
that of conventional ones. The move toward efficient building construction can be
accelerated through building codes and standards.
Illustrative model simulations for an “artificial” city suggest improvement po-
tentials of at least a factor of 2 if more energy-efficient buildings and more compact
urban forms (at least medium density and mixed use layouts) are enacted. Also
implicated in such a simulation is energy systems optimization through distrib-
uted generation and resulting cogeneration of electricity, heat, and air conditioning
(adding another 10-15% improvement in efficiency in urban energy use). Cogen-
eration is discussed in
Chapter 11
.
Urbanization is increasing dramatically in Brazil, China, India, and other countries
in which the bulk of new construction is taking place in the commercial sector. In
India projected growth of the commercial building sector is 7% per year. Its built
area currently totals only 200 million m
2
, but, by 2030, it is expected that 869 mil-
lion m
2
of additional space of commercial buildings will be constructed in its cit-
ies.
About 70% of the world's energy is consumed in cities, even though only ap-
proximately one-half of the world's population lives in cities. In most developing
countries, particularly in China, city residents use almost twice as much energy as
the national average due to higher income. In the United States and the European
Union, where income is more evenly distributed, energy consumption in cities is
slightly lower than the national average because suburbs and rural areas are wealth-
ier, houses are larger, and car and trucks are used more than in cities.
In urban areas, systemic characteristics are generally more important determ-
inants of energy use efficiency than the characteristics of individual consumers
or technological artifacts. For instance, the share of high occupancy public and/or
nonmotorized transport modes in urban transit is a more important determinant of
urban-transport-energy use than the efficiency of the vehicle fleet.
Incremental tightening of building codes and building standards and specific-
ations is an essential factor in driving building construction and even cities more
