Solar Tower Technology.
                     SOLAR TOWER 
TECHNOLOGY
INTRODUCTION
• Solar power towers convert sunshine 
into clean electricity. 
• The technology uses many large, sun-
tracking mirrors commonly referred to 
as heliostats to focus sunlight on a 
receiver at the top of a tower.
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TECHNOLOGY
• A heat transfer fluid heated in the 
receiver is used to generate steam, 
which, in turn, is used in a conventional 
turbine-generator to produce electricity.
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COMPARISION
• Early power towers such as the Solar 
One plant used steam as the heat 
transfer fluid. 
• Current power towers, based on Solar 
Two, use molten nitrate salt because of 
its superior heat transfer and energy 
storage capabilities.
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SOLAR ONE
• Solar One was the world’s largest 
power tower plant, which operated 
from 1982 to 1988 in the Mojave 
Desert. 
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THERMAL STORAGE SYSTEM
• The Solar One thermal storage system 
extended the power generation 
capability of the plant into the night 
and provided heat for generating low-
grade steam for keeping parts of the 
plant warm during off-hours and for 
morning start-up.
Source: www.azocleantech.com
SOLAR TWO
• The expansion of Solar One to Solar 
Two required a new molten-salt heat 
transfer system and a new control 
system which allowed the heliostats to 
track the sun. 
• This included the receiver, thermal 
storage, piping, and a steam generator.
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SOLAR TWO DESIGN
• The design included laser-welding, 
sophisticated tube-nozzle-header 
connections, a tube clip design that 
facilitated tube expansion and 
contraction, and non-contact flux 
measurement devices, which allowed 
the receiver to rapidly change 
temperature without being damaged.
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ADVANTAGES OF USING MOLTEN SALT
• A variety of fluids were tested to 
transport the sun's heat, including 
water, air, oil, and sodium, before 
molten salt was chosen: it is liquid at 
atmospheric pressure, provides an 
efficient, low-cost medium.
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BENEFITS OF SOLAR POWER TOWERS
• Solar power towers are unique among 
solar electric technologies in their 
ability to efficiently store solar energy 
and dispatch electricity to the grid 
when needed, even at night or during 
cloudy weather.
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ENVIRONMENTAL IMPACT
• No hazardous gaseous or liquid 
emissions are released during 
operation of the solar power tower 
plant. 
• Salt is picked up with a shovel and can 
be recycled if necessary. 
• If the power tower is hybridized with a 
conventional fossil plant, emissions will 
be released from the non-solar portion 
of the plant.
Source: www.azocleantech.com