People have tried to build prototype power stations of this kind before. One was in Cuba but was destroyed
by the waves. There is a non-net-power-generating protototype in Hawaii. These things need
power to to pump the water up, which must be less than the power generated.
I believe it is hard to build these things because you need a very wide pipe going down to deep ocean, to minimize loss to viscosity, but the pipe also has to be strong enough to withstand storm currents. This makes the installation very expensive.
I found some info in
http://www.eere.energy.gov/consumer/renewable_ener gy/ocean/index.cfm/mytopic=50010
Site says:
"OTEC power plants require substantial capital investment upfront. OTEC researchers believe private sector firms probably will be unwilling to make the enormous initial investment required to build large-scale plants until the price of fossil fuels increases dramatically or until national governments provide financial incentives. Another factor hindering the commercialization of OTEC is that there are only a few hundred land-based sites in the tropics where deep-ocean water is close enough to shore to make OTEC plants feasible."
At school they used to leave one of the physics labs open. Me and my friends used to go in and hook up those tin-can-shaped capacitors backwards to the power supply. It makes them blow up. It gave us no end of fun... but they do create a bad smell.
I hadn't heard that the Australian solar tower used cold water. I assume these are sprayed
from the top to cause air to fall somehow, but does the air fall inside outside the tower?
The falling-cold-air idea, in which you cool air high up by spraying water into it, and then
let it fall down a tower, is perhaps a good one. Apparently an israeli inventor has patented this. I dont think it can be done with a vortex because the pressure inside the tower is positive
not negative, in this case.
The vortex can be sustained by either a specific heat source, like seawater or
an area covered by greenhouses [as in the Australian solar tower/solar chimney],
or if the atmosphere is sufficiently humid it can be sustained by the inherent
instability of the atmosphere. However this instability is not generally always present.
This instability is called the CAPE (convective atmospheric potential energy). It is the energy source that feeds thunderstorms. The reason the atmosphere
can store energy is that the bottom layer of the atmosphere tends to be heated by the sun.
If the air is damp but not at 100% humidity you can get a situation where the air column is stable, but as soon as
it is perturbed enough for some of the air to start releasing moisture (when it reaches
100% humidity) the situtation becomes unstable. This is because the air that rises high enough to
release moisture, starts getting warmed up when the moisture precipitates and then rises even
higher.
Theoretically, this could be exploited by a vortex.
The vortex is performing the same function as a very tall tower, but hopefully more cheaply.
It's like a siphon that siphons gasoline out of your tank. The vortex has lower pressure at the
center, much like a siphon.
However, it is far from clear whether this idea could be made practical. There are issues like
how stable the vortex would be in wind, etc.
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People have tried to build prototype power stations of this kind before. One was in Cuba but was destroyed by the waves. There is a non-net-power-generating protototype in Hawaii. These things need power to to pump the water up, which must be less than the power generated. I believe it is hard to build these things because you need a very wide pipe going down to deep ocean, to minimize loss to viscosity, but the pipe also has to be strong enough to withstand storm currents. This makes the installation very expensive. I found some info in http://www.eere.energy.gov/consumer/renewable_ener gy/ocean/index.cfm/mytopic=50010
Site says:
"OTEC power plants require substantial capital investment upfront. OTEC researchers believe private sector firms probably will be unwilling to make the enormous initial investment required to build large-scale plants until the price of fossil fuels increases dramatically or until national governments provide financial incentives. Another factor hindering the commercialization of OTEC is that there are only a few hundred land-based sites in the tropics where deep-ocean water is close enough to shore to make OTEC plants feasible."
At school they used to leave one of the physics labs open. Me and my friends used to go in
and hook up those tin-can-shaped capacitors backwards to the power supply. It makes them blow up.
It gave us no end of fun... but they do create a bad smell.
I hadn't heard that the Australian solar tower used cold water. I assume these are sprayed from the top to cause air to fall somehow, but does the air fall inside outside the tower? The falling-cold-air idea, in which you cool air high up by spraying water into it, and then let it fall down a tower, is perhaps a good one. Apparently an israeli inventor has patented this. I dont think it can be done with a vortex because the pressure inside the tower is positive not negative, in this case.
The vortex can be sustained by either a specific heat source, like seawater or an area covered by greenhouses [as in the Australian solar tower/solar chimney], or if the atmosphere is sufficiently humid it can be sustained by the inherent instability of the atmosphere. However this instability is not generally always present. This instability is called the CAPE (convective atmospheric potential energy). It is the energy source that feeds thunderstorms. The reason the atmosphere can store energy is that the bottom layer of the atmosphere tends to be heated by the sun. If the air is damp but not at 100% humidity you can get a situation where the air column is stable, but as soon as it is perturbed enough for some of the air to start releasing moisture (when it reaches 100% humidity) the situtation becomes unstable. This is because the air that rises high enough to release moisture, starts getting warmed up when the moisture precipitates and then rises even higher. Theoretically, this could be exploited by a vortex. The vortex is performing the same function as a very tall tower, but hopefully more cheaply. It's like a siphon that siphons gasoline out of your tank. The vortex has lower pressure at the center, much like a siphon. However, it is far from clear whether this idea could be made practical. There are issues like how stable the vortex would be in wind, etc.