Online version: PDF - DTIE
Online version: PDF - DTIE
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UNIT 5: THE SUSTAINABLE SITING, DESIGN AND CONSTRUCTION OF TOURISM FACILITIES<br />
179<br />
• The deregulation of energy markets gives renewables open access to<br />
national electricity grids. Power companies are offering businesses<br />
and homes the choice of using ‘green’ electricity generated from<br />
renewables;<br />
• Equipment and appliances are becoming ever more energy-efficient.<br />
This makes the use of renewable energy increasingly feasible;<br />
• Concerns about air quality, global warming and climate change provide<br />
added impetus to reducing both our dependence on fossil fuels and<br />
greenhouse-gas emissions. This is increasing the focus on renewable<br />
energy sources.<br />
Many governments and power companies provide loans, grants and subsidies to<br />
promote the use of renewable energy. For tourism and hospitality businesses in<br />
rural areas, including those more than a kilometre away from the national grid,<br />
renewable energy is usually a good cost-efficient alternative, especially in view of<br />
the financial and environment costs of extending the grid.<br />
S<br />
E<br />
C<br />
T<br />
I<br />
O<br />
N<br />
3<br />
Solar Water-Heating<br />
Solar water-heating is well<br />
established as a cost-effective<br />
To<br />
water<br />
tap<br />
and sustainable energy source for hot water<br />
supply. The technology consists of:<br />
• A collector surface heated by the sun,<br />
over which the water to be heated<br />
passes;<br />
• A heat-transfer medium;<br />
• A storage tankback-up water heaters<br />
to meet peak demand periods, to heat<br />
water to higher temperatures, or to<br />
provide hot water when there is no<br />
sun.<br />
Casing<br />
Storage tank<br />
Lower<br />
conduit<br />
Upper<br />
conduit<br />
To optimise exposure to sunlight, collector<br />
panels are usually put on the roof, either<br />
flush on the surface or up on brackets. If<br />
Water flow<br />
roof space is not available, the panels can<br />
also be installed at ground level, with the disadvantage that if the building is more<br />
than one storey high, the hot water will have to be pumped to higher levels, using<br />
additional energy (e.g. an electric pump).<br />
For best performance, collector plates should face north when in the southern<br />
hemisphere and south when in the northern hemisphere. They should be inclined<br />
at an angle from the horizontal equal to the latitude, although this may vary<br />
with latitude. The most efficient systems include collector panels with special<br />
coatings which absorb direct solar radiation (visible light) and radiate little direct<br />
heat (infrared radiation) back into the surrounding air. This enables the collector<br />
to reach much higher temperatures, meaning smaller collectors to heat larger<br />
amounts of water, which in turn can greatly reduce the space required.<br />
In colder climates, it is necessary to have a freeze protection on the panels to<br />
prevent damage from the expansion of water in the collector pipes. Anti-freeze<br />
solar technology includes cells with anti-freeze liquid, panels fitted with small<br />
electric heaters, or anti-freeze valves.<br />
Active solar heating –<br />
collector plate of a solar water<br />
heater with storage tank<br />
Source: ETSU/DTI<br />
Transparent<br />
cover<br />
Black<br />
absorber<br />
plate<br />
Insulation