Sorry for the pun, but just recently I saw a feature on the use of
rising air channels in buildings turning turbines, exploiting
temperature differentials between air at ground level and air up high.
Apparently, air temperature falls roughly 1 degree C for every 100m.

Outside of towns in our outback in Australia, ambient temperatures
during the day even in winter typically average 35 - 40 degrees C.

Suppose we built a large heat absorbing area, covered in blackened
metal plates with some moltne saline mixture underneath it -- say 2500
sqm. Over it, we place a canopy -- perhaps perspex or something
similar that lets light through at about 3m above, elaving just a
small gap at the base for air to enter and leaving about 25 m external
clearance, so as to create a hot area surrounding it to diminish
fugitive air pushing out or dust being sucked in.

We place parabolic dishes around the side to concentrate the
insolation on the central area and in the middle we build a huge
cylindrical tower 2500 meteres high with a turbine at the top to allow
the heated air at the base to escape.

I know that there is a formula for energy gathered by a turbine based
on factoring in wind speed, swept area and air density but I've no
idea how to calculate these in a setting like this. I don't know how
hot the air under the canopy would get -- clearly it whould be a hell
of a lot hotter than the ambinet temperature and the temperature
differential should be very significant -- but how much?

Any ideas?

Fran

Sorry for the pun, but just recently I saw a feature on the use of
rising air channels in buildings turning turbines, exploiting
temperature differentials between air at ground level and air up high.
Apparently, air temperature falls roughly 1 degree C for every 100m.

Outside of towns in our outback in Australia, ambient temperatures
during the day even in winter typically average 35 - 40 degrees C.

Suppose we built a large heat absorbing area, covered in blackened
metal plates with some moltne saline mixture underneath it -- say 2500
sqm. Over it, we place a canopy -- perhaps perspex or something
similar that lets light through at about 3m above, elaving just a
small gap at the base for air to enter and leaving about 25 m external
clearance, so as to create a hot area surrounding it to diminish
fugitive air pushing out or dust being sucked in.

We place parabolic dishes around the side to concentrate the
insolation on the central area and in the middle we build a huge
cylindrical tower 2500 meteres high with a turbine at the top to allow
the heated air at the base to escape.

I know that there is a formula for energy gathered by a turbine based
on factoring in wind speed, swept area and air density but I've no
idea how to calculate these in a setting like this. I don't know how
hot the air under the canopy would get -- clearly it whould be a hell
of a lot hotter than the ambinet temperature and the temperature
differential should be very significant -- but how much?

Any ideas?

Fran

Sorry for the pun, but just recently I saw a feature on the use of
rising air channels in buildings turning turbines, exploiting
temperature differentials between air at ground level and air up high.
Apparently, air temperature falls roughly 1 degree C for every 100m.

Outside of towns in our outback in Australia, ambient temperatures
during the day even in winter typically average 35 - 40 degrees C.

Suppose we built a large heat absorbing area, covered in blackened
metal plates with some moltne saline mixture underneath it -- say 2500
sqm. Over it, we place a canopy -- perhaps perspex or something
similar that lets light through at about 3m above, elaving just a
small gap at the base for air to enter and leaving about 25 m external
clearance, so as to create a hot area surrounding it to diminish
fugitive air pushing out or dust being sucked in.

We place parabolic dishes around the side to concentrate the
insolation on the central area and in the middle we build a huge
cylindrical tower 2500 meteres high with a turbine at the top to allow
the heated air at the base to escape.

I know that there is a formula for energy gathered by a turbine based
on factoring in wind speed, swept area and air density but I've no
idea how to calculate these in a setting like this. I don't know how
hot the air under the canopy would get -- clearly it whould be a hell
of a lot hotter than the ambinet temperature and the temperature
differential should be very significant -- but how much?

Any ideas?

Fran