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Solar heating market
overview |
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Reported in PHAM news Managing editor Derek
Johnson gives an overview of the Solar heating Market.
The rate of growth of solar energy installations In the UK
must be one of the best kept secrets in the industry. When
I decided to take a look at this area I was aware that the
market was changing but I had no idea just how far and how
fast it was moving nor was I aware of the range of applications
and industry sectors adopting the technology. It is no longer
a technology just for heating private swimming pools or for
supplementing the water heating systems of those passionate
about 'alternative technologies'. The development is such
that it is now being used extensively, not just in the domestic
sector but also in the commercial and local authority/housing
association area. |
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This means, of course, that there are a number
of contracting companies out there capitalising on this demand.
Just as an illustration, I was talking to one installer, a
small company, who the next week was beginning the installation
of solar water heating systems in no less than six local primary
schools, Another example is the installation of both solar
water heating and photovoltaic (PV) systems for a housing
trust in East London.
Solar water heating
The basic principles of solar water heating are well known.
Heat from the sun is absorbed by a collector, the heat transferred
to a water system which supplies a cylinder to preheat domestic
hot water or to a pool directly for pool heating. However,
it is in the design of the collectors and the system where
development has been made and, although the most simple of
DIY designs will work to a greater or (usually) lesser extent,
to obtain the maximum benefit, system and collectors must
be matched to each other and the property just as with any
other type of heating.
Solar photovoltaics(PV)
Solar photovoltaic energy came out of the development of
semi-conductors in the 1950s and is simply the conversion
of sunlight to electricity. It is a particularly interesting
and attractive technology because there are no moving parts,
no emissions, no noise and long life. It can be used to power
pumps (for instance on a solar water heating system) and provide
the power for low energy appliances and lighting. |
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Drivers for change
the present climate of low cost fuel one might question
why industry, commerce and government, local and national,
as well as private domestic property owners are investing
in what are essentially capital intensive systems? The answer
is twofold: firstly; the cost of fuel is set to rise increasingly
quickly in the not too distant future and secondly; Government
pressure to reduce the CO2 emissions dramatically by 2010.
In the commercial and local authority sector it is this latter
factor, with legislation such as the Climate Change Levy,
which is driving the move towards technologies which either
minimise or do not use fossil fuels with consequent reduction
in emissions. |
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| Although the installation of a solar system in
a school for example may be more capital intensive than a straight
forward boiler system the fuel cost savings will be progressively
higher year on year and maintenance should also be reduced.
With the Government emphasis now firmly on whole life costing,
the initial capital cost has much less significance than before
and running costs much greater importance. |
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Available power
The amount of radiation falling on the Earth varies according
to the latitude, being highest at the Equator which is why
solar energy is used extensively in Mediterranean countries,
the Middle East etc. About 1.4 kW/m2 of solar energy falls
on the outer atmosphere and on the latitudes of Western Europe
the maximum under clear skies at midday is about 1.0kW/m2,
Depending on the type of collector up to 75% of this : energy
can be converted into heat (ie 7.5kW per 10 meter squared
of collector), Translating this into annual energy savings,
a suitably designed solar collector system matched to correctly
designed system components can save 50 -60% of the annual
energy requirements for domestic hot water in residential
properties. Full potential energy savings would be achieved
if the other heat source backing the solar system were a condensing
boiler.
The importance of solar energy in the World context is evidenced
by it being a significant category in the World Energy Renewable
Network (WREN) which is a network of worldwide organisations
promoting environmentally safe and economically sustainable
renewable energy; It was established to support and enhance
the utilisation and implementation of renewable energy sources,
to further the communication and technical education of scientists,
engineers, technicians and managers in this field and to address
itself to the energy needs of both developing and developed
countries.
The solar thermal activities are diverse ranging from basic
research to product development in a very broad scope of applications
from water heating, space heating, refrigeration, cooling,
drying, desalination to power generation.
Photovoltaics ranges from single stand alone systems to those
which are fully grid connected, from a few Watts output to
multi MegaWatt systems with even GigaWatt networks being contemplated.
The industry has come along way from the days of heating
an outdoor pool by spraying water from a hosepipe over a black
plastic sheet and letting the water drain into the pool! |
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