The production and storage of renewable energy sources has been studied extensively in the past few decades. A novel innovative way to produce energy using buoyancy forces was recently patented. The invention is called the Buoyancy Prime Mover turbine, or simply Air Wheel, and was developed and patented in the USA by Luis M. Carrion and Carlos A. Carrion in March, 2012. This turbine creates a torque capable of moving an electric generator. The Carrion brothers cooperated with the Polytechnic University of Puerto Rico, Interamerican University of Bayamon of Puerto Rico and the engineer, Emanuele Quaranta, of Turin (Italy). At the moment, they are looking for applications worldwide.
How Does the Air Wheel Work?
The air wheel is a turbine made of twelve buoys, all of which are immersed in resting water. The buoys are disposed along a circular line around a central shaft, which represents the rotational axis of the turbine. The six buoys on one side are filled with air, while the six buoys on the other side are filled with water. The buoys filled with air undergo a buoyancy force, that creates a torque at the shaft. In this way, the turbine rotates; since the turbine is connected to a generator, electricity can be produced. The difficulty of this arrangement is that the water content inside each buoy has to be regulated. When the buoy is on the water-filled side, it is filled with water. When the buoy reaches the other side, water must be ejected from the buoy, and substituted by air, in order to generate the buoyancy force at the buoy. For providing this, the water volume inside the buoy is controlled by injecting compressed air into it, so that the water is totally expelled when the buoy approaches the air filled side. Therefore, each buoy is connected to a chamber with compressed air by a small tube. The diameter of the wheel is about 3 meters and the rotational speed is 8 revolutions per minute.
What Makes This Turbine Unique?
The air wheel exploits the fact that air is lighter than water. This is the opposite principle of the water wheel, which exploits the fact that water is heavier than air.
The air wheel can be used in hydropower marine systems (hydropower marine systems exploit the energy of marine current and waves to generate energy). The air wheel can be driven by wave energy; wave energy is used to move pistons and to create compressed air that is stored in the compressed air chamber, then exploited by the air wheel.
The air wheel is also useful to use the compressed air stored during the low energy demand period, when there is a surplus of produced energy. For example, when the demand for energy is lower than the production, and the hydropower system is designed for working at a constant regime, energy has to be accumulated or dispersed. The former option is obviously preferable. On the other side, hydropower marine systems that work with a variable regime, adapting their production with the demand, are more expensive and complex. With the introduction of the air wheel, marine hydropower systems can be designed to work at a constant regime; when the demand is lower than the production, the excess of energy can be used to produce and store compressed air. The compressed air is stored in a chamber and used successively to drive the air wheel during the peaks of energy demand, thus when the demand is higher than the production.
Perspectives
The air wheel represents a new turbine to use in marine hydropower systems. The air wheel simplifies the costs and design complexity of marine hydropower systems.
Since this technology has just been patented, at the moment, the air wheel and the system are being studied and investigated in order to be optimized, and their costs reduced. Its application can be of interest to a lot of companies specialized in energy and marine systems.
