Environmental Engineering Reference
In-Depth Information
Global energy demand was 12.38 Gtoe (16.5 TW) in 2010 and is expected to rise
to 16.73 Gtoe (22.2 TW) by 2035 (IEA
2014
). While the energy demand for coun-
tries in the Organization for Economic Co-operation and Development (OECD) is
expected to decrease during the 2010-2035 period, rising living standards in China,
India, the Middle East, and non-OECD countries will cause the global energy de-
mand to increase by more than one-third by 2035.
There will also be several new energy trends that are likely to occur over the
2014-2035 period. For instance:
• The US and Brazil will become major energy exporters due to the use of hydrau-
lic fracturing commonly referred to in the US and Europe as “fracking”, while
deep-water drilling technologies off countries such as Brazil will also obtain
unconventional gas and oil. Such trends will increase the supply of liquefied
natural gas (LNG).
• The expansion of the Panama Canal, which is scheduled to be completed in 2015,
will give larger liquefied natural gas (LNG) transport vessels access to Asia. The
prospect of being able to readily transport LNG from South and North America
means that LNG will become a globalized market in the period 2015-2035.
• Coal as an energy source will shift to Asia with coal consumption by India in
2035 being roughly that of China, Japan and the European Union (IEA
2014
).
This means that many new power plants that use coal will need to be built and
that it will be very important to develop cleaner and more efficient combustion
technologies for coal.
• As much as 90 % of Middle East oil will be exported to Asia by 2035 so that
combustion processes will need attention to their design.
As such trends develop, it is essential that the new energy systems being built have
high efficiencies so that catastrophic damage to the environment does not occur.
Energy systems that use fluids in their supercritical state have the potential to
reduce energy consumption, reduce pollution and emissions to the environment and
improve the global environment and living standards. Fluids in their supercritical
state especially when used as working fluids in heat pumps can make highly effi-
cient energy systems because there is no phase change for a fluid in its supercritical
state.
5.2
The Supercritical State of Substances
The critical point of a substance is defined as the highest temperature and pressure
for which vapor and liquid can co-exist in equilibrium (Fig.
5.2
). The supercritical
state occurs when a fluid is at conditions above its critical temperature and criti-
cal pressure. Many small molecules (H
2
O, CO
2
) have well-defined critical points
whereas large molecules (polymers, waxes) decompose at conditions below their
critical temperature.
