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SOLAR THERMAL POWER TOWER
Presented by RAMESH V
USN:4MC06ME084
1. 1. INTRODUCTIONINTRODUCTION2.SYSTEM DESCRIPTION2.SYSTEM DESCRIPTION3.RANKINE CYCLE3.RANKINE CYCLE4.HELIOSTAT4.HELIOSTAT5.WORKING OF SOLAR TOWER5.WORKING OF SOLAR TOWER6.SOLAR ONE6.SOLAR ONE7.SOLAR TWO7.SOLAR TWO8.USE OF MOLTEN SALT8.USE OF MOLTEN SALT99.REQUIREMENTS.REQUIREMENTS10. APPLICATION10. APPLICATION11.CONCLUSION11.CONCLUSION
CONTENTS
INTRODUCTION
The solar thermal power tower is a type of solar furnace using a tower to receive the focused sunlight. It uses an array of flat, moveable mirrors to focus the sun's rays upon a collector tower. The high energy at this point of concentrated sunlight is transferred to a substance that can store the heat for later use.
SYSTEM DESCRIPTION AND WORKING
RANKINE CYCLE
There are four processes in the Rankine cycle, each changing the state of the working fluid.
Process 4-1: First, the working fluid is pumped from low to high pressure by a pump. Pumping requires a power input.
Process 1-2: The high pressure liquid enters a boiler where it is heated at constant pressure by an external heat source to become a superheated vapor.
Process 2-3: The superheated vapor expands through a turbine to generate power output.
Process 3-4: The vapor then enters a condenser where it is cooled to become a saturated liquid. This liquid then re-enters the pump and the cycle repeats.
HELIOSTAT
A Heliostat is a device that tracks the movement of the sun. It is typically used to orient a mirror, throughout the day, to reflect sunlight in a consistent direction. When coupled together in sufficient quantities, the reflected sunlight from the heliostats can generate an enormous amount of heat if all are oriented towards the same target. It was originally developed as an instrument for use in surveying, allowing the accurate observation of a known point from a distance.
SOLAR ONE
Solar One, which operated from 1982 to 1988, was the world’s largest power tower plant. It proved that large-scale power production with power towers was feasible.
The project met most of its technical objectives by demonstrating(1)The feasibility of generating power with a power tower(2)The ability to generate 10 MW for eight hours a day at summer solstice and four hours a day at winter solstice.
Solar Two has produced 10 MW of electricity with enough thermal storage to continue to operate the turbine at full capacity for three hours after the sun has set.
The Solar Two receiver comprises a series of panels (each made of 32 thin-walled, stainless steel tubes) through which the molten salt flows in a separate path.
The energy storage system for Solar Two consists of 875,000 liter storage tanks.Thermal capacity of the system is 110MWh
SOLAR TWO
The molten salt is a mixture of 60 percent sodium and 40 percent potassium-nitrate, commonly called saltpeter.
The salt melts at 430°F and is kept liquid at 550°F in an insulated cold storage tank.
USE OF MOLTEN SALT
The salt is pumped to the top of the tower where concentrated sunlight heats it in a receiver to 1050°F. The heated salt then flows back down to a second insulated 'hot' storage tank. From here, it can be pumped to a generator that creates superheated steam to drive a turbine or it can be stored and its thermal energy used later.
ADVANTAGES OF USING MOLTEN SALT
It is liquid at atmospheric pressure.
It provides an efficient , low cost medium in which to store thermal energy,
Its operating temperatures are compatible with today's high-pressure and high temperature steam turbines,
Land(Acreage) :Acreage needs for a parabolic trough or compact
linear Fresnel reflector development would average about 5 acres/megawatt (MW), while acreage for the other solar technologies would average about 9 acres/MW. Acreage needs increase if the solar field is oversized to take advantage of thermal or electrical storage
LAND AND WATER REQUIREMENTS
Water:Parabolic trough, compact linear Fresnel reflector, and
power tower technologies would require up to 15 acre-feet per year per megawatt for wet cooling or up to 1.5 ac-ft/yr/MW for dry cooling. Water required for mirror washing would be about 0.5 ac-ft/yr/MW.
Turbine size
Capacity cost
Installed capital cost
Annual operation and maintenance cost
Annual fuel cost
Levelized energy cost
100 MW
100MW
200MW
200MW
27% Solar9% Fossil40%Solar
40% Solar
63%Solar
$256M
$328M
$564M
$800M
$4.9M
$4.9M
$6.1M
$7.4M
$3M
-
-
-
114/KWh
114/KWh
94/KWh
84/KWh
ENERGY COST OF SOLAR POWER TOWER
APPLICATIONS
1)The solar thermal systems convert the radiant energy of the sun into heat, and then use that heat energy as desired.
2)The solar electric systems convert the radiant energy of the sun directly into electrical energy, which can then be used as most electrical energy is used today
CONCLUSION
Solar thermal power towers meet the needs of today’s utility
grids.
The technology for solar thermal power towers is proven.
The cost performance and reliability of solar thermal power
towers can be confidently predicted.
Power towers will produce electricity at a competitive cost.
THANK YOU..