THE EFFECT OF WIND SPEED AT THE TOP OF THE TOWER ON THE PERFORMANCE AND ENERGY GENERATED FROM THERMOSYPHON SOLAR TURBINE

Energy generated from wind turbine depends to a great extent on the wind speed at
its inlet. The use of thermosyphon solar tower is an attempt to increase the air
velocity at inlet of the wind turbine and of course to increase its power. The wind
speed in a certain location changes always with time and with the height above
ground surface. In this work, the effect of wind speed at the top of the tower on the
performance as well as on the energy generated from therrnosyphon solar turbine
was studied theoretically. One location in Egypt was chosen for this study. The
calculations were achieved mainly with the solar turbine located at tower bottom. For
the purpose of comparison, the energy generated from the solar turbine was
compared with that generated from free wind turbine at tower height with the
absence of solar tower.
It was found that, the wind speed at the top of the tower results in a pressure drop
which affects the performance of the thermosyphon solar turbine. This pressure drop
increases with the rise in wind speed and will be zero only when the wind speed at
the top of the tower reaches zero. It was also found that, there is an increase in
friction losses through the tower and a decrease in both temperature difference
between inlet and outlet of the tower and in heat losses from tower walls with the rise
in wind speed. The inlet air velocity to the solar turbine and consequently its specific
power were found to be increased with the increase in wind speed at the top of the
tower. Therefore, the effect of wind speed at the top of the tower must be taken into
account during therrnosyphon solar tower calculations. By comparing the
performance of solar turbine and the free wind turbine located at tower height with
the absence of thermosyphon solar tower, it was found that the mean inlet air
velocity to the solar turbine located at tower bottom and consequently its specific
power are higher than those values for free wind turbine. The increase in mean inlet
air velocity to the solar turbine is found to be 17 % of its value for a free wind turbine.
The increase in yearly specific energy generated from solar turbine is expected to be
57 % of its value for free wind turbine