Here is a way to generate energy from warm seawater.
This may look complicated but it uses simple technology.
To start, electricity is sent down deep into a warm lake or ocean.
Oxygen and hydrogen are produced using electrolysis.
The gases come up thru separate pipes causing a large volume of water to rise up thru the pipes.
This is referred to as a bubble pump and can produce very large flows of water.
The high water pressure deep under the sea, which is produced by gravity, causes this flow of water.
As the gases rise they decompress and cool, chilling the water.
The water is kept from freezing by taking on heat from the surrounding water thru heat sinks on the riser pipes.
The gases are then separated from the water in settling tanks.
The cold water is then warmed by sea-water in a heat exchanger
(or run thru a heat engine) before entering special turbine generators.
There the cold gases mix with the warm water causing the gases to expand increasing the push on the
turbine blades, much like in a jet engine.
Further decompression of the gases thru the turbine causes the water to cool down again as the heat
is converted to mechanical energy.
In a final step, the temperature difference between the cold water and the warm ocean or lake is used
by heat engines (such as a Sterling engine or Minto wheel) to drive electric generators.
The O2 and the H2 are used by fuel cells to generate electricity.
The electricity produced is used to power the electrolysis.
This starts the whole process over again.
Extra electricity or hydrogen is removed for use as an energy source.
This is not perpetual motion anymore than a dam on a river.
The energy comes from sea-water warmed by the sun and from gravity.
are: How much does high-pressure affect electrolysis? Can enough energy be
harnessed to exceed all the losses involved? Can the electrodes be kept working
deep in the ocean or lake? Can a turbine be designed to mix warm water with cold
gases and harness the extra energy of the expanding gasses? Is there a heat engine
that will work on small temperature differences? Can the gases be
filtered enough to prevent damage to the fuel cells? Will the gases dissolve into
the water and not be recycled?
My rough calculations show a slightly positive
energy flow. My web research says that high pressure affects the electrolysis very little.
My web research also shows that conversion of electricity to water and back to electricity,
using fuel cells and PEM technology looses about 50% of the energy. A pressure
differential is produced in the pipes by the displacement of the water by
gas bubbles as they rise in the pipes. As the bubbles rise they will expand and
cool. If allowed to cool too much they could easily freeze the water, turning
it into slush. Heat sinks on the pipes would move heat from the warm sea
into the water in the pipes keeping the water liquid. The temperature in the
first separation tanks would be just slightly above freezing. The pressure would
be just slightly lower than the weight of the displaced water. The water is
now warmed up thru a heat exchanger (or optionally a heat engine) to near ocean temperature
thus taking on heat from the warm sea. The gases and water are now at the same pressure
but the water is warmer. Both enter a turbine where the water warms the gas
producing a higher pressure. The gas and water mixture exits the turbine at near
normal pressure but chilled by the decompressing gases. The gas is again
separated and goes on to the fuel cells. The cold water then is used to power a
heat engine (such as a Sterling engine or Minto wheel) using the warmer sea
water as a heat differential. A heat engine could also be used in place of the
At this time I do not know exactly how
much power might be lost thru the turbines or the (Sterling or Minto) heat engines. My
research and best guesses show that, allowing for the losses in the turbines,
heat engines, and the generators, the pressure (or using old fashion hydroelectric
terminology "head") produced by the rising
bubbles could produce enough power to more than make up the
50% lost in the electrolysis and fuel cells. My best guess
is maybe break even to 15% excess energy out during each cycle.
Thus at this time this does not appear to be a very economical way to
produce energy. But if improvements are made in fuel cell technology and/or a
good design for the turbine or the heat engine, then this free energy
might climb to 50% or more. Or maybe my numbers are wrong?
I do know that if
loses are neglected, there is much more energy out than is sent down to the electrodes!
This energy comes from a number of facts:
The energy needed to electrolysis water is affected very little by high pressure.
B. Energy can be extracted from pressure differentials.
D. Energy can be extracted from temperature differentials.
High pressure can be transferred from deep in the sea to the surface using water displacement of bubbles.
E. A temperature differential is created by the decompressing gases.
F. The sun warms the sea replenishing the temperature differential.
G. Gravity pressing on the sea replenishes the pressure differential.
A large share of electricity needed for electrolysis can be recovered thru reverse electrolysis in fuel cells.
I. The temperature and pressure differentials can generate mechanical energy.
J. The mechanical energy can generate electrical energy.
The electricity output is very much more than the electricity input (neglecting losses)
The final question is: Are the losses more, or less
than the extra energy extracted from the heat of the sea and the push of gravity? All that
is needed to do is design the most efficient
methods of harnessing these temperature and
pressure differentials. The sea could be replaced by a large diameter, very deep hole in
the ground filled with water warmed by solar energy. Or by a large diameter pipe running to
the top of a skyscraper building warmed by solar energy and kept full with rainwater.
The heat engines could be improved Minto wheels. Mr. Minto's energy
harnessing wheels were featured in the Mother Earth News magazine many
years ago. The Minto wheels were a pair of tanks or barrels on opposite ends of a pipe,
all filled with a low boiling point liquid (such as propane). Heat on the bottom tank forced
the liquid up into the top tank, overbalancing the wheel. Gravity pushed the top tank around to
the bottom starting a new cycle. The Mother Earth News spent a lot of money building a very large
only to have it fail to live up to expectations. Rather than look
at why it failed, they discarded the whole idea as inefficient. I know why their
wheel failed. I know how to improve the Minto wheel to make it very efficient. Needed is
someone with the ability to design a turbine capable of using room temperature
pressurized water and cold pressurized hydrogen or oxygen efficiently. The alterative is to use
seperate turbines for the water and the gas. Also needed is research or experience concerning
the gases dissolving in water, whether this would be a problem.
November 12, 2000
James R. Randall
Stockbridge, Michigan USA