Goal
Capture mechanical energy from upward heat-convection in the atmosphere to generate renewable electricity and improve the efficiency of thermal power plants.
Problem
Large amounts of waste heat from power plants and the need for carbon-free, renewable electricity.
Concept Summary
A cylindrical vertical structure with tangential air in at its base is heated (by steam, solar, waste-heat, warm sea water, etc.) to start a tall, slow-moving vortex. The vortex acts as a virtual chimney, drawing warm humid air upward and creating a pressure differential that drives low-speed air turbines, producing electricity. The system can be integrated as a bottoming cycle for existing power plants or as a stand-alone solar-heated vortex.
Detailed Description
The AVE consists of a concrete or steel cylindrical wall open at the top. Tangential ducts (louvers) at the base admit ambient air, which is briefly heated by a diffuser (steam or other heat source) to initiate vortex formation. Once established, the vortex is sustained by the natural heat content of warm humid air or by waste heat from a cooling tower. The vortex creates a low-pressure column that draws additional air through the louvers, increasing mass flow. Air-driven turbines placed in the flow path convert the kinetic energy of the vortex into electricity, typically yielding about 20 % additional power from waste heat. The design includes a lower ring of louvers to maximize mass flow and an upper ring to seal the vortex, with wall height 5-30 x the louvers height to retain stability against cross-winds. Prototypes have been built in Utah and a 1-m scale model is under wind-tunnel testing at the University of Western Ontario.
Principles
- Convection
- Vortex dynamics
- Thermodynamics
- Fluid mechanics
- Pressure differential conversion
Scientific Domains
Materials
- Concrete
- Steel
- Metal (louvers, turbines)
Mechanisms of Action
- Heat-induced upward air movement
- Vortex formation via tangential air entry
- Low-pressure column driving air flow
- Air-turbine rotation converting kinetic energy to electricity
Energy Sources
Applications
- Electricity generation for grid
- Bottoming cycle for thermal power plants
- Carbon-free energy from waste heat
Claimed Performance
Approximately twenty percent additional electric power from waste heat that would otherwise be discarded by conventional power plants.
Experimental Evidence
Prototype built in Utah with colleague Tom Fletcher; wind-tunnel testing of a 1-m scale model at the University of Western Ontario; Breakout Labs funded a 2012 test with $300 k grant; preliminary results reported in The Atlantic (2015).
Replication Status
Prototype constructed; wind-tunnel testing conducted; Breakout Labs test performed.
Limitations
- Large structural height required for efficient vortex
- Stability under cross-winds
- Control of vortex intensity to avoid hazards
- Scalability and economic viability not yet demonstrated
Red Flags
- Potential for uncontrolled tornado-like vortex
- Safety concerns in populated areas
- Claims of carbon-free energy without extensive peer-reviewed data