Who asserts that the energy cannot be created from nothing does not include that the compressed air is not "nothing." Unlike battery-powered batteries, compressed air can be clamped in a tight volume and work like a compressed spring that transmits its strength to uncompressible water, which circles a part of the same, entering and exiting from the same volume, by means of a pump with the dual power supply separated until the impeller, which allows this operation by spending very little energy because the water, being incomprehensible, in the rotating impeller, sums the two flow rates with a single pressure, which is that of compressed air. However, it can produce electricity through a hydraulic turbine under the thrust of compressed air imprisoned that is not consumed. Since the energy produced by the turbine (which depends on compressed air pressure) is hundreds of times higher than that consumed by the pump (which recycles the water inside the accumulated volume), this system is fully autonomously energized and only needs of a small starter battery, which opens the solenoid valve that supplies the water in the turbine with compressed air force. But this system is much cheaper and cleaner than thermal motors and battery cars and can not be compared even with cars that are running on the market that work with compressed air (pneumatic engines) by consuming the compressed air accumulated in Tanks, which need to be recharged by consuming electricity, such as battery cars, and therefore cost more and have little autonomy. Obviously, hydroelectric power generators with water recycled pressurized with air can be mounted on all moving and mobile working vehicles, including aerospace aircraft. Where, to travel in the atmosphere, we have to move very large volumes of air, creating vacuum around the aircraft and exploiting Newton's reaction principle. While for space travel it is sufficient only the amount of compressed air, stored in tanks in the aircraft that is entered in small doses in the thrust electric turbofans. Obviously, the flight system proposed by the Earth's atmosphere is much safer than the current one, but requires much higher energies. It can only be achieved with energy that does not cost anything and does not produce pollution, such as compressed hydroelectric power.
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