Environmental Engineering Reference
In-Depth Information
roofs or on facades. This is especially apparent in new suburbs or in historic
districts where regulations regarding heights and facade colours and materi-
als might need to change to accommodate the new installations.
On the urban scale, a new paradigm should govern how we plan our cities,
orient our buildings and plot our roads. Different variations are needed to
improve the environmental performance of the city and to reduce thermal
loads on buildings, thereby reducing the need for future cooling/heating and
the accompanying consumption of energy. Other issues are how to smartly
plan the locations for needed renewable power plants and how to connect
them efficiently to different buildings. Planning new cities should have these
criteria embedded in the infrastructure of the city and not simply as later
add-ons. This approach is extensively adopted in city of Masdar in the United
Arab Emirates.
10.4 Energy-Efficient Building Envelopes
The building envelope, also known as the building shell, fabric or enclosure,
is the boundary between the conditioned interior of a building and the out-
doors. The energy performance of building envelope components, including
external walls, floors, roofs, ceilings, windows and doors, is critical in deter-
mining how much energy is required for heating and cooling. The building
envelope's impact on energy consumption should not be underestimated: glob-
ally, space heating and cooling account for more than one-third of all energy
consumed in buildings, rising to as much as 50% in cold climates and more
than 60% in the residential subsector in cold climate countries.
Overall, one can conclude that buildings are responsible for more than
35% of global energy consumption. It is very alarming that, although whole-
building approaches are ideal, every day building envelope components are
upgraded or replaced using technologies that are less efficient than the best
options available. These advanced options, which are among the primary
focus of this topic, are needed not only to support whole-building approaches
but also to improve the energy efficiency of individual components.
Building envelopes are expected to save almost 6 exajoules (EJ) in 2050
under the two-degree Celsius scenario (equivalent to the current energy
consumption of the United Kingdom). The goal is to change the way of con-
structing building to save energy: an inevitable solution.
The main issues are as follows:
1. The construction of new buildings should offer the best opportunity
to deploy passive heating and cooling designs, which make use of
energy-efficient building materials to minimise energy required for
heating and cooling.
