Civil Engineering Reference
In-Depth Information
particularly the fast-economy-growing Asia countries, still grows. Increased fossil
fuel consumption has led to continuous rising of carbon emission to the envi-
ronment (Wikipedia
2011
), which is thought to be the direct reason causing the
global warming.
Solar thermal is currently providing only 0.5 % of total primary energy need
and solar PV has even lower energy supply ratio of 0.04 % (IEA
2007
). Both solar
thermal and PV technologies have far high space to grow which would be driven
by the continuous technical advances and increased concerns of energy saving and
environment protection. This development would certainly contribute to signifi-
cant reduction in fossil fuel consumption and cut of carbon emission.
Solar thermal is one of the most cost-effective renewable energy technologies
and has huge market potential globally. It, representing more than 90 % of the
world-installed solar capacity, is utilised for various purposes including domestic
hot water generation and space heating, solar-assisted cooling and industrial
process heating. The global solar thermal market has been continuously growing
since the beginning of the 1990s. In the EU, solar thermal market was tripled from
2002 to 2006 and still in booming. A vision plan issued by European Solar
Thermal Technology Platform (ESTTP
2009
) indicated that by 2030, up to 50 %
of the low- and medium-temperature heat will be delivered by solar thermal. The
European Solar Thermal Industry Federation (ESTIF
2007
) has predicted that by
2020, the EU will reach a total operational solar thermal capacity of between 91
and 320 giga-Watts (GW), thus leading to saving of equivalent to at least
5,600 tons crude oil. By 2050, the EU will eventually achieve 1,200 GW of solar
thermal capacity (ESTIF
2007
).
PV is currently a technically and commercially matured technology able to
generate and supply short-/mid-term electricity using solar energy. Although
current PV installations are still small and provide only 0.1 % of world total
electricity generation, a market review indicated that the global PV installations
are growing at a 40 % average annual rate (IEA
2010
). With continuous technical
advance, increased installation volume, reduced price and encouraging legal pol-
icies, PV will certainly continue on the fast-growing pace and eventually become
an important energy supplier. It is predicted by IEA at its recent Technology
Roadmap—Solar Photovoltaic Energy that PV will deliver about 5 % of global
power need by 2030 and 11 % by 2050. The accelerated use of PV will result in
more than 100 giga-tons (Gt) of CO
2
emission reduction during the period of
between 2008 and 2050 (IEA
2010
).
PV/T is a hybrid technology combining PV and solar thermal components into
a single module to enhance the solar conversion efficiency of the module and make
economic use of the building space. A PV/T module can simultaneously generate
electricity and heat and therefore takes advantages of both PV and solar thermal
technologies. The dual functions of the PV/T result in a higher overall solar
conversion rate than those of standard PV or solar collector and thus enable a more
effective use of solar energy. Its market potential is therefore expected to be higher
than individual PV and solar thermal systems. However, since the PV/T is a
recently
emerging
technology,
various
issues
relevant
to
PV/T,
e.g.
current
