08-16-2017, 10:14 PM
SOLAR CHIMNEY
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INTRODUCTION
Solar chimney electricity generation power plants are referred to as solar updraft towers and the related solar chimneys are huge reinforced concrete structures.
However due to the high construction cost of the concrete solar chimneys the solar up-draft tower technology is expensive demanding a high initial investment in comparison to its competitive solar technologies. Their solar up-draft towers are huge structures of high initial investment cost that cannot be split into small units. That is possible for the relatively also expensive PV solar technology.
Floating solar chimney (FSC) technology, is a low cost alternative of the solar updraft towers. The FSC technology is the advisable one for candidacy for large scale solar electricity generation especially in desert or semi desert areas of our planet and a major technology for the global warming elimination.
The Floating Solar Chimney Power Plant, named by the author as Solar Aero-Electric Power Plant (SAEP) due to its similarity to the Hydro-Electric power plant, is a set of three major components:
The Solar Collector (greenhouse)
It is a large greenhouse open at its periphery with a transparent roof supported a few meters above the ground.
The Floating Solar Chimney (FSC).
It is a tall fabric cylinder placed at the centre of the solar collector through which the warm air of the greenhouse, due to its relative buoyancy to the ambient air, is up-drafting. Floating Solar Chimney is patented by the author in USA and several other countries.
The Electric Power Unit.
It is a set of air turbines geared to appropriate electric generators in the path of up-drafting warm air flow that are forced to rotate generating electricity. The gear boxes are adjusting the rotation speed of the air turbines to the generator rotation speed defined by the grid frequency and their pole pairs.
The energy source, for the rotation of the air turbines and the electricity generation, is the horizontal solar irradiation passing through the transparent roof of the greenhouse and heating the ground beneath it. The ground thermal energy is partly transferred to the air stream, entering the greenhouse and moving towards the FSC bottom entrance.
The up-drafting air mass through the FSC, due to its relative buoyancy to the ambient air, is offering a part of its thermodynamic energy to the air turbines rotating the geared electric generators, which generate electricity.
PARTS OF THE SOLAR CHIMNEY
a) The Collector: Collector is the part, which is used to produce hot air by green house effect. It is usually five to six meters high and covers a very large area about thousands of m2 as shown in the below figure.
Since glazing increases the mass of roof, glazed collectors should have stronger rods and should be attached as shown in the below figure.