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Old 08-26-2012, 04:07 PM
Realist Realist is offline
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Join Date: Aug 2012
Location: MO
Posts: 3
Quote:
Originally Posted by Michael C View Post
Heat loss from the compressed air is a true problem. Also, a turbine acts differently on steam or on air. Usable steam has to be superheated (after water being evolved into steam, it needs to be heated once more in order to have a temperature margin to prevent too much condensing).

Run the turbine on compressed air alone, so it can be optimized for that energy medium. Use the solar/heat energy in some way to produce compressed air instead. Steam is the most economical way to transport heat energy. It would be possible to build a heat exchanger that produces compressed air, just a few spring loaded valves needed.

In electrics, 'back-EMF' is a known phenomena. The same thing happens when you close a water crane rapidly, the water pipes may vibrate and that's from a strong wave of 'water-EMF' from the cutoff. With a simple membrane pump, this backwards force have been harvested since the 1700's to raise water high above the level from where it came to the pump.

So, why not harvest that energy with the medium of air, in order to produce compressed air? Remember, speed generated from a certain steam pressure will have more energy than that very same pressure. Steam can pick up water from the outside and push it back into the steam vessel without any losses except heat energy. Search for the function of the Gresham injector for instance. Use this knowledge to build an air compressor with no other moving parts than spring valves or membranes. The sun could be the source of energy to that.
A very good book to compressed air is "Compressed Air" from Montana School of Mines.
Impulse water pumps utilize the velocity of water in a pipe, nothing else. The velocity is momentum; when the flow is halted (in a valve), the momentum must be converted, usually to a pulse in a smaller pipe. Height is limited by initial water velocity.

When air is compressed, the energy of that air is concentrated in heat. Compress air at sea level and 60F to 15 psi and the heat rise will be roughly to 140F. If this heat is lost, so is the energy required in compression. When the compressed air is used, it will cool to that temperature necessary to perform the work required. Easy checkout: compress air into a tank, let it cool, then release the pressure. Once you've done that, feel the tank and see how cold it is. That's lost energy.

Rules of physics, that's all.
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