1. Hello, my name is Louis Michaud.
AVE stands for Atmospheric Vortex Engine.
An Atmospheric Vortex Engine is a machine for producing a controlled vortex and for capturing the mechanical energy produced when heat is carried upward by convection.
As a process engineer I realized that more work is produced by the expansion of a warm gas than is required to compress the same gas after it has been cooled. The process had to be responsible for tornadoes.
AVE means “hello” or “welcome” in Latin. Therefore Hello everyone and welcome to our Energy Future.
Here is a photo of a cooling tower at a Spanish nuclear power plant that has been touched to show what an AVE could look like.

2. The lower half of the drawing shows a side view of an AVE.
The upper half of the drawing shows a plan view of an AVE.
The vortex is formed by admitting warm air in a circular arena via tangential entry ducts thereby causing the air to spin about the vertical axis and a vortex to form over the center of the arena.
A roof with a circular opening at its center causes a vortex to form.
The air is heated or humidified in heat exchangers located upstream of the tangential entries.
The mechanical energy is produced in peripheral turbines.
The reduced pressure at the base of the vortex is the driving force for the flow.
The vortex would look like a small tornado at the centre of a large arena. There is no equipment near the vortex base because anything near the vortex could interfere with vortex formation.

3. Vortex Arena Water cooler and Air heater Warm water Warm air
Here is an illustration of an AVE where the heat exchanger is a wet cooling tower.
Water cooler
and Air heater
Warm water
Turbine &
generator
Warm air
Ambient air
Cool water
Illustration by:
Charles Floyd

4. Wet cooling tower AVE – Side view Capacity approximately 200 MW
Here is a side view of AVE where the heat source is a wet cooling tower.

5. The thermodynamic basis of the AVE is the same as that of the solar chimney.
The solar chimney at the upper left was built in Spain in the 1980’s had a chimney 200 m high and an electrical output of 50 kW. It operated successfully for 7 years.
The proposed Australian solar tower at the lower left would have a chimney 1 km high and an electrical capacity of 200 MW.
A chimney is a cylinder in radial compression; at any level the pressure is less inside than outside.
The glass covered solar collector increases the air temperature by approximately 20°C.
The pressure difference at the base of the chimney, the draft, is proportional to the temperature difference and to the chimney height.
The AVE replaces the physical wall of the chimney with centrifugal force in a vortex.
Notice how short the solar chimneys on the left are compared to the AVE on the right.
For a given air flow power production is proportional to draft and draft is proportional to temperature difference and to chimney height.
With a chimney 1000 m high the 50 kW of the Spanish chimney could have produced with a temperature difference of 4°C.
With a chimney 10 km high the 50 kW of the Spanish chimney could have produced with a temperature difference of 0.4°C.
With a chimney high enough there is no need for a solar collector. There are many natural sources of surface heat warmer than the overlying air.

6. Here is a side view of AVE where the heat source is a wet cooling tower.

7. Cooling Towers
Mechanical Draft: $15 million 40 m tall mechanical draft tower uses 1% to 4% of power output to drive fans. (uses energy)
Industrial plants use cooling towers to send waste heat in the atmosphere.
The mechanical draft cooling tower at the upper left uses induced draft fans to draw air through falling water. Driving these fans can consume up 1 to 4% of the power output of a thermal power plant.
The natural draft cooling tower at the upper right uses a tall stack to draw the air through the falling water and does not require fans, but it has a much higher capital cost.
In the vortex engine at the lower left, the stack effect is achieved without the physical stack. The draft can be high enough to drive turbines and thereby increase the power output of the power plant.
Process engineers are skilled at using natural convection to avoid having to provide prime movers such as pumps and fans. Work of convection is rarely sufficient to justify providing equipment for its capture.
Natural Draft: doesn’t need fans but is 150 m tall and costs $60 million. (saves energy)
Vortex Cooling Tower: $15 million 40 m tall to function like a natural draft tower. (produces energy!)

8. Prototype
Vortex
Here are photographs of vortices produced with a 4 m diameter prototype in the summer of 2008.

9. Here is an Earth’s energy budget from NASA.
The heat carried upward by convection averages 102 W/m2; 24 W/m2 as sensible heat and 78 W/m2 as latent heat.
There is a potential of converting approximately 12% of the heat carried upward by convection to mechanical energy.
12% is an average efficiency; for heat carried up to the upper troposphere the conversion efficiency can as high as 30%.

10. This figure shows the energy production potential of the Atmospheric Vortex Engine.
The numbers are staggering:
The solar energy received by the Earth is 174,000 TW,
The global electrical energy production rate is 2 TW,
The total thermal energy produced by humans is 15 TW,
The heat carried upward by convection in the atmosphere averages 52,000 TW,
Converting 12% of the heat carried upward by convection to mechanical would produce 6,000 TW.
The mechanical energy production potential of atmospheric convection is 3000 our electric energy production.
The mechanical energy production potential of atmospheric convection is 400 our total energy production.

11. A hurricane viewed as a Carnot cycle
Here is the thermodynamic cycle of the hurricane process by Kerry Emanuel of MIT.
The air is heated by the sea surface at a temperature of 300 K and cooled at high elevation at lower temperatures.
For a hot source temperature of 300 K, the efficiency would be 33%.
Dr. Kerry Emanuel was named one of the most influential scientist of 2005 by Times magazine for having predicted increased hurricane intensity as a result of global warming before Katrina.
Emanuel compared a hurricane to a Carnot Engine receiving heat from the surface at a temperature of 300 K and giving up heat in the upper troposphere at a temperature of of 200 K with an efficiency of 33%.
A large hurricane can produce more energy than all the energy produced by humans in a year.
A medium size tornado can produce as much energy as a large thermal power plant.
Efficiency
n = 1 – Tc / Th = 1 – 200/300 = 33%
Source Divine Wind by Kerry Emanuel

12. Here is another view the AVE Power Cycle.
The efficiency of an ideal cycle is essentially equal to the efficiency of a Carnot cycle wherein the hot and cold source temperatures are the log average of the temperatures at which heat is received and given up.
An ideal cycle requires an expander to constrain the expansion and to capture the resulting work.

13. Gravity Power Cycle Here is the ideal cycle for the AVE.
The cycle is the same as the gas-turbine ideal cycle shown in the next slide except that the expansion takes place in stationary tall conduits instead of in mechanical turbines and compressor.
The operating conditions are the same in the two cases.
In both ideal cycles, the air is heated from 290 K to 300 K at a pressure of 100 kPa and cooled from 189.4 K to 183.1 K at the 20 kPa level.
The gas is heated a constant pressure, expanded in the turbine, cooled at constant pressure, and compressed back to its original pressure.
The work produced by the expansion of the warm gas is more than required to compress the cooled gas and the excess is available to drive a load.
Once an ideal cycle is understood it is easy analyze irreversible cycles by taking into account the effect of turbine efficiency, friction losses, and kinetic energy.
The efficiency of the AVE cycle can be reduce to zero by simply replacing the turbine with a restriction. There cannot be any work produced unless there is a shaft to take the work out of the system.

14. Brayton gas-turbine power cycle
Here is the standard Brayton gas-turbine ideal cycle.
The work of compression appears explicitly in the gas-turbine case but is not as evident in the gravity cycle.
In the gravity cycle the gas expands as it rise and is compressed as it descends.
The efficiency of an ideal Brayton cycle is strictly a function of its pressure ratio. The ideal cycle efficiency for a compression ratio of 5:1 is 36.9%.
The key to understanding thermodynamics is simplification.
Engineers use ideal processes: with no friction loss, negligible velocity, and without temperature difference during the heat transfer. Real processes are difficult to analyze, but it is usually possible to conceive of ideal process that is easily to analyze.
In reversible cycle analysis the size of the conduits and the fluid velocity is of no importance; the downflow conduit can be much larger in cross sectional area than the upflow conduit.

15. This diagram shows how an AVE can be combined with a conventional power plant.
The brown bottom half of the diagram represents a conventional coal power plant.
The green upper half represents the AVE.
Conventional thermal engines operate in the lower half of the diagram and reject heat at temperatures close to the temperature at the bottom of the atmosphere.
Conventional thermal engines need a temperature difference of at least 100°C; but efficiency is improved by maximizing hot source temperature.
Using a vortex to carry the heat upward would permit rejecting heat at the temperature at the top of the top of the troposphere thereby increasing cycle efficiency.
A combined vortex engine could increase the overall efficiency of a power plant from 35% to 48%.
The vortex engine permits the use of heat at temperatures too low to be useful when the heat sink is the temperature at the bottom of the atmosphere.

16. Back in 1905 Austrian thermodynamist Max Margules used a piston covered closed insulated thermodynamic system to investigate how wind energy is produced.
One dimensional models are the most basic type of meteorological model. In order to understand what is going on you have to go two steps simpler and specify that the air in the system initially has uniform entropy and that bottom layer is a unit mass.
With uniform entropy, air masses can be moved isentropically without requiring work.
The figure shows that work can be calculated in several ways all giving the same result:
1. From the difference between the heat received and the heat given up.
2. From the heat received multiplied by the Carnot efficiency.
3. From the total energy equation.
The three states batch process shows that the mechanical energy is produced during lifting process 2-3. The work is not produced during heating process 1-2 or cooling process 3-1.
The re-arrangement process can occur well after the heating process therefore mechanical energy production can occur anytime after the heat is received.
Margules used large air masses making it difficult to see the relationship better Carnot efficiency and work production.
Once the concept is understood, it is easy to show the work production is always equal to the heat required to re-establish the initial condition multiplied by the Carnot efficiency.
Margules did not explain how the isentropic process could be carried out.

17. Atmospheric work production process
Energy conservation in an open system
Margules used a closed piston covered thermodynamic system but it is possible arrive at the same result with an open thermodynamic system like this one.
Open thermodynamics system such as this one are commonly used by engineers to calculate the minimum work required or the maximum work that can be produced when a fluid is moved form one place to another.
When there is no change in elevation like in a gas turbine the work is the reduction in enthalpy; when there is change in elevation like in a hydraulic turbine the work is the reduction in potential energy.
In the AVE both terms must be considered.

18. This figure shows that work production requires a heat source at low level and a heat sink at a higher level.

19. Reversible and Irreversible Expansion

20. This figure shows that expansion must be constrained to realize the work production potential.
If the piston is restrained the work is the isentropic expansion work.
If the latch is let go without restraining the piston, the maximum work that can be produced is the work required to push the 95 kPa surrounding air out of the way. Any additional potential for doing work remains in the cylinder air in the form of heat.
The work lost as a result of unrestrained expansion is approximately 22% of the isentropic expansion work.
22% of the work is lost irrespective of how small the pressure difference.
Since the net cycle work is typically less that 22% of the total expansion work, loss work as a result of unconstrained expansion can easily consume all the net cycle work.
Consider a rising bag loosely filled with buoyant air. As the bag rises the surrounding pressure decreases, the pressure inside the bag becomes higher the pressure outside the bag; the pressure are not balanced. There is insufficient resistance for the air inside the bag to push against therefore part of the work (about 22%) of expansion work is lost.

21. Thermodynamic Calculation Method
Here is the Ideal Process for the vortex engine. The complete ideal cycle is useful for understanding the energy transformation process but a partial cycle is sufficient for work calculation.
The process consist of three parts:
Process 1-2: Isentropic expansion in a turbine,
Process 2-3: Constant pressure heating and humidification in a wet exchanger,
Process 3-4: Isentropic expansion in a vertical upflow tube.

22. Here is a sample atmospheric sounding.
The green line is the temperature of the environment.
The blue line is the temperature of a rising parcel of surface air when there is no heating or humidification during process 2-3.
The red line is the temperature of a parcel of surface air with heating and humidification during process 2-3. The temperature of the air in state 3 is 1°C less than the sea surface temperature of 30.4°C (29.4°C). The humidity of the air in state is 90% (10% approach to saturation).
The net work is proportional to the area between the green sounding curve and the rising air temperature (the red or green lines).
Heating during process 2-3 increases the area between the curves and the work.

23. Typical Energy Calculations – SST 30.4 C
This table shows results for a range of approaches to Sea Surface Temperature (SST).
Left column, case 0 - No heating, corresponds to the blue line on the previous sounding.
Middle column, case 2 - Termperature approach (A) 1°C, Relative humidity approach (B) 10%. Corresponding to the red line on the sounding.
Right column, case 4 – Air saturated at SST
In case 2 the work is J/kg corresponding to a velocity of 180 m/s.
The work in Case 2 is more than sufficient to explain the maximum velocity of 110 m/s observed in hurricanes and tornadoes.
The bottom line shows that the increment in work is approximately 30% of the added heat added in the cooling tower irrespective of whether the heat is supplied in the form of sensitive or latent heat.

24. Hurricane Isabel Intensity SST 25 to 26.5 C
Temperature approach 1 C - Relative humidity 97%
Hurricane Isabel (2003) provided excellent wind speed, sounding properties and SST data.
Wind data showed sustained wind speeds of 77 m/s and one gust of 107 m/s.
Dropwindsonde data showed eyewall air temperature 1°C lower than SST and eyewall air relative humidity of 97%.
SST temperature measurements showed eyewall SST between 25.5 and 26.5°C.
The above calculations were carried out to see if the observed conditions could account for the observed wind speed.
The above result show:
that a SST of 25.5°C can produce a wind speed of 78 m/s.
and that a SST of 26.5°C can produce a wind peed of 110 m/s
Hurricane wind sprays water droplet in the air. The droplets get cooled to their wet bulb temperature and transfer heat from water to air. The heat capacity of water is much greater than the heat capacity of the air therefore the air temperature tends to approach the sea temperature.
The process is similar to a wet cooling tower. The heat transfer between spray droplet and air can be much higher than the heat transfer between air and an underlying flat surface.

25. Hurricane Isabel effect on sea surface temperature as observed from satellite
The blue path is this satellite image clearly shows the cooling effect of hurricane Isabel.
Orange represent SST over 30°C; blue represents SST under 27°C.
The wet bulb temperature of pre hurricane surface air with a typical relative humidity of 80% is 25°C.
The wet bulb temperature of hurricane eyewall air with 97% relative humidity is approximately 24°C.
The passage of a hurricanes can reduce SST by 3 to 6°C.
The evaporatively cooled droplets fall back in the sea and cool the SST
The cooled surface water sinks and is replaced by underlying water so long as there is underlying warm water thereby preventing the surface water from cooling below approximately 25°C.
Source:

26. Here is a comparison of the Earth’s stored energy resources.
The latent heat content of the water vapor in the bottom kilometer of the atmosphere is twice the heat content of all the Earth’s petroleum reserves.
The sensible heat available by cooling the top 100 m of tropical water by 3°C is 20 times as much as the heat content of the oil reserves.
The heat released in an average hurricane is 5 x 1019 Joules/day. Enough to cool a strip of ocean 500 km long by 100 km wide and 100 m deep by 3°C.
At the present consumption rate the remaining world’s oil reserve will be used up in approximately 30 years.
The cooling effect of hurricanes on sea water and its replenishment time are clearly visible on infrared satellite photos.

28. Effect of entrainment and ambient
relative humidity on updraft buoyancy

29. Subsidence warming and radiative cooling
The temperature of the subsidizing air increases at the dry adiabatic lapse rate of 9.8°C/km, line 1-3.
The lapse rate in the troposphere is typically 6.5°C/km.
The troposphere is cooled by infrared radiation to space by approximately 1.5°C/day, line 3-2.
Subsidence must be slow enough to give the subsiding air time to cool. Without radiative cooling descending air would arrive at the surface at its potential temperature.
A sustained subsidence rate exceeding 4 kPa/d (500 m/d) would increase the temperature of the troposphere.
Air descending from the 15 km level must take about 30 days to descend to prevent warming up the environment.
Imagine a number of columns of subsiding air. Subsidence would tend to occur in the column that is the coldest, but subsidence warms the column and therefore the subsidence shifts to the next coolest column.
Hurricanes transfer huge amount of heat from the sea to the atmosphere, but there is no corresponding increase in temperature in the tropical upper troposphere. The subsidence can occur a very long distance away. Periods of tropical hurricane activity are often accompanied by fair warm weather in high latitudes.