Introduction to Flat Plate Collectors:
Flat-plate
collectors are a very helpful device for low to medium temperature heat
collection from the sun. They can be used for a lot of uses including a
variety of thermal desalting process from low to medium capacities.
Flat-plate collectors enclose simple characteristics: they are simply
assembled, and effortlessly operated.
The
plan of any system that shifts solar radiant power into thermal energy
is the sensible application of the thermal energy itself. Solar Thermal
Energy application can be able to direct as heat or indirect by using
the heat to force a heat engine to produce useful mechanical energy or
to use the thermal energy for electrical energy production. For this
cause unique devices are used called solar thermal collectors. The
principle of a solar thermal collector is to absorb the radiant energy
of the sun and to convey the significant heat to a fluid which in turn
relocates the thermal energy to the place of relevance. In familiar,
solar collectors are classified according to their thermal output
temperature which establishes also the field of their application.
For solar applications to be suitable, this transport
headed for a lower temperature stage is important. While high-priced
high concentrating solar systems are essential to generate quantities of
steam or oil with temperatures of more than a few hundred degree
Celsius, temperatures below 150°C can be created by high efficiency
standard collectors without or with just low concentration of the solar
radiation.
Flat-plate
collectors are planned for applications require low to moderate
temperatures in general up to 110°C higher than ambient temperatures.
The simplest flat plate collectors are the solar ponds and the solar
stills which function by direct utilization of the incident solar
radiation acting simultaneously as solar energy converters. The
importance of flat-plate collectors is that their thermal performance.
Solar Collector Applications
Solar
collectors are very popular for setting up in a region where there are
high irradiation intensities and clear sunshine days. They can be
installed simply in individual houses for domestic hot water, in hotel
buildings and in municipal installations, such as athletic centres for
hot water use and for heating swimming pools.
Huge
mercantile installations with high capacity are used in industry to
produce process water or, in solar desalination plants to produce
moderate temperature water, as feed to low or medium temperature
distillation plants. In general they are useful tools for hot water
production.
The
higher temperatures required which will be achieved by the minimisation
of the collector U-value (Heat loss coefficient). It is in the nature
of the things that this minimisation of the U-value which increases the
stagnation temperature. Solar Thermal Collectors which are used in
thermal process heat applications (Range: up to 150°C), must reach
stagnation temperatures greater than 300°C. So all the parts of the
thermal collector such as selective absorber coatings for the black
absorber medium, insulation materials for the backside of the absorber
have to be able to endure high temperatures.
In
addition to thermal radiation losses the air inside the collector,
consistently at atmospheric pressure, is transferring energy primarily
by convection as well as by conduction. Hence the collectors itself have
to be insulated against the surroundings. Likewise the Back side of the
collector also insulated with a variety of temperature and humidity
resistant thick materials offered on the market, the front of the
collector is more awkward since it is out in the open to solar
radiation. Transparent insulation materials in addition high
transmittance for solar radiation with low heat conductance are required
to achieve more temperature.


No comments:
Post a Comment