Page 36 - Analysis and Design of Energy Geostructures

Energy and geotechnologies 5

Table 1.1 Some energy-related unit measures.
Name Symbol Description
Joule J 1 Joule is equal to the energy transferred to an object when a
force of 1 Newton acts on that object in the direction of its
motion through a distance of 1 m (1 J 5 1 Nm)
Basic energy unit of the metric system (SI)
Calorie cal 1 calorie is the amount of heat required to raise the

temperature of 1 gram of water by 1 C, from 14.5 Cto

15.5 C

The calorie can be defined in terms of the Joule
(thermochemical calorie: 1 cal 5 4.184 J)
Watt-hour Wh The standard unit of electricity production and consumption
3
(1 Wh 5 3.6 3 10 J)
Tonne of oil toe 1 toe is the amount of energy released by burning one ton of
equivalent crude oil (1 toe 5 41.868 GJ), that is an energy equivalence
for oil
Watt W or J/s A derived unit of power that expresses 1 Joule per second and
can be used to quantify the rate of energy transfer

classification includes renewable energy sources and nonrenewable energy sources. Renewable
energy sources, such as solar energy, geothermal energy, wind energy, hydropower
energy, tidal energy and biomass sources, can renew themselves at a sufficient rate in
human time frames. Nonrenewable energy sources, such as fossil fuels (e.g. oil, coal
and natural gas) and mineral fuels (e.g. natural uranium), cannot renew themselves at a
sufficient rate in human time frames.

1.2.3 World energy consumption and supply

Various are the uses of energy by human civilisation and associated with these uses
there is always an energy supply. Depending on the stage of the utilisation or produc-
tion of energy, three different definitions can be employed to characterise the use of

energy (as well as the energy itself), that is primary energy consumption, final energy con-
sumption and net energy consumption, and one definition to characterise the supply of
energy, that is primary energy supply (cf. Fig. 1.2). Primary energy consumption refers to
the direct use or supply at the source of energy that has not been subjected to any
conversion or transformation process. This energy is often termed primary energy or
crude energy as well. In most cases, however, energy cannot be used without conver-
sion or transformation processes and for this reason it is refined in the so-called final
energy. The final energy consumption represents the total energy consumed by end
users (e.g. the building sector, the industry sector, etc.), excluding the energy that is
used by the energy sector itself. In the context of constructions, this term is usually
associated with the amount of energy supplied that is necessary to run the generator of