The Revolution Energy Converter Explained - D R A F T -
Preface
1. Temperature Difference
2. Heat Transfer
3. Control
4. Pressure Difference
5. Pressure to work in the REC
6. Proof of concept
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The Revolution Energy Converter Explained - D R A F T -
A brand new motor that promises to replace today's polluting combustion engines is being developed.
The revolution Energy Converter (REC)
is the heart of a powerful sustainable heat engine with a wide range of applications.
Its simple concept is highly scalable, low cost, zero carbon, making the REC an
outstanding competitive solution.
Based on a totally new heat engine technology that builds on established knowledge
in heat transfer and thermodynamics controlled by computer logics makes it
difficult to compare with existing technology.
To explain this revolutionary concept, allowing the REC to transform temperature
gradients into power, the examples below gives a technical step by step illustration:
1. Temperature Difference – effect of temperature difference on a contained gas – the balloon example,
2. Heat Transfer – how to change temperature fast – the grilling sausage example,
3. Control – how to start, accelerate and stop the REC – explanation of the Revolving Shutter
(RS) and the “Revolution Dynamic Link” (RDL)
4. Pressure Difference – constant relation between temperature and pressure –
the umbrella in the wind and the sealed jar example,
5. Pressure to Energy – explanation of how to use pressure to get energy.
Example:
Blow up a balloon to full size, put it in the freezer and it will shrink. Taking the balloon back into room temperature, it will expand back into its original size (fig.1). This shows that the volume of a gas, the air in the balloon, changes with temperature.
Figure 1: Same balloon - different temperatures
Another example of this phenomenon is to close a jar with a
tight lid. As in the balloon case, it contains a closed volume but the size
can’t change, instead the internal pressure will change. If we put the sealed
jar in the freezer its internal pressure will decrease, however, putting
the jar on a hot stove will increase its internal pressure risking exploding.
This illustrates that heat change is power, this phenomenon is in the heart of the REC.
Explanation:
In a closed gaseous volume, the temperature can be used as a measure of energy. When a difference in energy occurs within a system, it will always strive to the least energy state; the heat spontaneously flows from a warm to a cold system to reach equilibrium.
When the gas in the balloon has the same temperature as the ambient air in the room, they are in thermal equilibrium. Putting the balloon in the freezer will start a heat transfer – a flow from a system with high temperature to a system with a lower temperature. Important to note is that all the gas stays inside the balloon, its only heat energy that leaves into the surrounding air inside the freezer. While striving for thermal equilibrium the pressure inside the balloon falls and it shrinks. Energy leaves until the balloon and the freezer reaches the least energy state i.e. thermal equilibrium. When the cool balloon is taken out from the freezer into room temperature, a new heat transfer process starts to reach a new thermal equilibrium. The direction of heat flow is now from the warmer room into the cool balloon. The balloon will expand back to its original size.
Translated in the REC:
The pressure exerted by a gas in a closed volume is proportional to its temperature.
The REC is a closed system that changes the temperature of its internal volume. It’s designed in such way that one side of the converter is connected to a heat source while the opposite side connects to a cold source (heat sink). By changing the temperature of its large gaseous volume, its internal overall pressure will change. The idea is to move the internal gaseous volume between the hot and the cold side, to heat up and cool down the same volume repeatedly, just as illustrated by the examples above.
These pressure changes of the total volume will be converted to power.
The experiments above are the proof of the concept, but they also show that heating up and cooling down a large gaseous volume is a time- consuming process. How could we speed up the temperature change? Let's light up the BBQ...
The Revolution Energy Converter Explained - D R A F T -
Put two Frankfurters, a Cumberland sausage and a thick black pudding on the BBQ. The thin Frankfurters are quickly grilled, the Cumberland sausage takes a bit longer as it’s a bit thicker, the black pudding will take ages because of its thickness. However, if the black pudding is cut into thin slices, thinner than both the Frankfurters and the Cumberland, it becomes the fastest to prepare.
The heat transfer in the REC, a sealed container,
works with the same slicing principle. The REC is holding a column of thin
slices (fig. 2) of a gaseous volume and will move these slices
between conducting fins of a heat-conducting block (fig. 3).
All the gaseous slices will simultaneously get heated on both sides as
they pass between the conducting fins.
Figure 2: Comparison of a thin slice of black pudding grilled on both sides with a slice of a gaseous volume heated on both sides in the REC.
The thin gaseous slices with large area heat up very quickly and the heat transfer is equally boosted by circulating vortexes inside each flat slice of the gaseous volume (fig. 2).
Figure 3: The thin slices of the gaseous volume passes between the conducting fins of a hot block where they heat up quickly.
The REC also has a cool conducting block, just like the hot block in figure 3, but with a lower temperature (fig. 4). Moving the column of the thin gaseous slices over to the cool side, the whole volume equally cools down very fast while passing between the cool conducting fins.
The closed REC system repetitively heats
up and cools down the large sliced column of the gaseous volume to create
changes in its internal pressure (e.g. jar example). The column of the
gaseous volume is also the only carrier of heat from the hot block to the
cold block.
The direction of heat transfer is from the hot block where
the heat is transferred from the large areas of the hot conducting fins
into the column of gaseous slices and the pressure rises. The hot slices
are then simultaneously shovelled over the cold block to transfer its heat to the
large areas of the cold conducting fins that will lead away the heat and
cool down all the slices and the internal pressure will fall. Once the
column of the sliced volume is cooled down, it’s shovelled back to the
hot block where heat transfer starts from the hot conducting fins to the
thin gaseous slices and the internal pressure rises again.
Figure 4: Conducting fin blocks for heating and cooling the column of the sliced gaseous volume to create internal pressure changes. The direction of heat transfer is from a region of high temperature to a region of lower temperature. Arrows show the transfer of the heat of the volume from the hot block to the cool block where the slices dump their heat.
Thin slices with large area heats up and cools down faster than thick volumes.
The REC is a closed system that heats up and cools down a large sliced volume
efficiently, fast and repetitively which results in internal pressure changes.
Following sections will explain how the gaseous column is shovelled between
the hot and cold blocks and how to get important use from the pressure changes.
The Revolution Energy Converter Explained - D R A F T -
The closed REC uses an internal “Revolving Shutter” (RS) to move the sliced gaseous volume column between the hot and the cold block to create internal pressure changes. The RS (fig. 5) is a pack of disks with a quarter opening “the sliced volume”.
Figure 5: Illustrates the free wheeled RS with its quarter opening which passes between the conducting fins.
All the slices of the gaseous column are held within the quarter opening (fig. 6).
Figure 6: Illustrates the sliced gaseous volume column, in blue, contained within the RS
When the RS rotates,
it moves all the slices of volume between the hot and the cold conducting
fins (fig. 7). The RS is not in contact with the fins and is free wheel
turned by a controller with logics and an electric stepper motor. The turning
of the freewheeling RS and thereby the flow of the sliced gaseous volume
does not require very much force to rotate. Although the RS purpose is
only to swish around gas, it must be controlled at every instant.
Figure 7: The sliced gaseous volume is rotated between the hot and the cold block. Only bottom fins of blocks are showing.
The controller is called the “Revolution Dynamic Link” (RDL). The
RDL software is continuously adjusting the RS speed according to input
from the running application. It’s designed for variable speed as well
as varying work load. The RDL is also used in constant speed applications
since it adds the great advantage of total control of start and stop and
keeping an exactly specified speed.
Figure 8: A view of inside the REC with the hot and cold blocks and their respectively conducting fins in red and blue, the electric operated RS in brown with the quarter openings which contain the slices of volume described in fig. 6. The hot and the cold blocks are separated by insulating nil blocks in transparent beige. One of the nil blocks (empty space closest to the viewer) has been removed in order to see the RS opening.
The RDL software controls the internal RS (fig. 8) shovelling the volume slices
between the hot and cold fins.
As heat travels
from high to low temperature, all spontaneous heat transfer between the hot
and the cold side need to be blocked with insulation as the heat must only
be carried by the column of thin slices within the RS.
To prevent leakage within the slices, they are not
supposed to be in contact with the
hot and the cold side at the same time therefore no overlapping is allowed.
To prevent this unwanted efficiency leak, the REC contains two insulating
“nil blocks” (fig. 8) with insulating fins placed in-between the hot and
the cold block opposite each other.
These insulating nil blocks prevents simultaneously heating up and cooling
down parts of the same volume.
The Revolution Energy Converter Explained - D R A F T -
The pressure exerted by a fixed volume of a gas is proportional to its
temperature. It means that a certain temperature difference always results
in a certain pressure difference for a gas in a fixed volume, no matter
the size of the volume.
A 1L jar filled with air and tightly sealed
with a lid in room temperature of 20°C is heated to 100°C. The internal
pressure will rise from ambient room pressure of 101kPa (kilo Pascal) to
129kPa.
In the same way, a larger 10L jar filled with air and tightly sealed in
20°C is heated to 100°C. The internal pressure of the jar will equally
rise from 101kPa to 129kPa.
This example stresses that the pressure
difference in the two different containers remains equal. Why bother using
a large jar (larger volume) when the pressure difference only depends on
the temperature difference? This is a very valid question!
Pressure is
the amount of force acting per unit area (newton per square metre) and
is measured in pascal (Pa). Consequently, having the pressure to work on
a larger area will result in a larger force. If you are walking against
the wind in rainy weather and fold out an umbrella, the wind will almost
blow you away until it has turned your umbrella into a funnel, useless
for rain protection.
This example shows the wind pressure wasn’t really bothering you until
you exposed it to the large area of the umbrella. The same pressure, but
acting on a larger area – will almost blow you away.
The broken umbrella with a reduced area, would allow you to walk steady,
though you get wet.
The formula “Pressure times Area equals Force” and the schematic figure (fig. 9) are at the base of the REC ; P · A = F where P is pressure, A is the piston area, F is the force perpendicular to the top area of the piston.
When the internal pressure of the REC becomes higher than ambient
the piston is pushed outwards. This happens when all the volume slices
are between the hot fins, i.e. the shutter opening is on the hot side
(fig.9). When the shutter opening moves the sliced column of the volume
over to the cold block, the internal pressure will fall, and the outside
ambient pressure will push back the piston in the other direction. This
force is usable in both directions.
Figure 9: P is the REC internal pressure. A is the piston head area. F is the force you get. A larger piston area (A) delivers more force (F) but requires a larger REC volume to move the same displacement (the RS opening is on the hot side in this illustration).
The lower the temperature difference, the lower the internal pressure.
This compensates by adding volume and using a large piston area, as shown
in the formula P · A = F
At high temperature differences, e.g. when burning raw methane gas,
the REC can be built small and compact, suitable for transports in
general (car, bus, truck etc.)
At lower temperature differences, like
waste heat recovery or solar heat, the REC may be built in very large
stationary units with a larger volume and piston area, still able to
deliver great power (power plants for electricity) but from a low
temperature difference.
The Revolution Energy Converter Explained - D R A F T -
The REC with its logically controlled revolving
shutter, RS, is a closed system. A “moving boundary” is introduced to
the system by connecting a piston or a membrane to the REC. This will allow
for volumetric changes inside the closed system, which in turn will create
a force. As the moving boundary reciprocates because of the changes in pressure,
boundary work, or simply work, is generated. How work is generated by a moving
boundary in a closed system can be described by classical thermodynamics.
A schematic of the conversion from heat to work in the REC, described above,
is illustrated in fig.
9. Each of the volume slices in the column, are
placed on the hot side of the REC (horizontal white straps). As the volume
is heated, the build-up in pressure difference forces the boundary to move
and generate work. All the slices in the column
builds up one single
work generating volume.
Extracting work from heat is step-wise described
in the following paragraph:
1. The electric controller motor positions
the opening of the RS (c.f. fig 6.) to overlap with the hot block of the REC,
2. heat-transfer from the hot fins into the slices of gaseous volume takes place,
3. the internal pressure (P) of the REC rises and forces the piston,
with area (A), to move a given distance (ds),
4. the controller motor turns the slices of
the
work generating volume (RS openings) to the fins on the cold side where they
will dump their heat,
5. the internal pressure drops and the piston returns to its original position,
i.e., pushed back the distance ds. The process restarts from 1
Since the 2nd law of thermodynamics dictates that the direction of heat
transfer is from hot to cold, it’s possible to control the heat transfer
between the work generating volume (RS openings) and the fins. In this
manner, the pressure drop within the closed system can be controlled.
As mentioned, the effect of the internal pressure change of the REC is a
displacement of the piston distance, here denoted ds.
During this event, work is performed on the piston and this is the reason why
the white slices of the gaseous column in fig.9. is called the
work generating volume.
Work (w) is performed when
a force (F) is applied and displaces an object over a
distance (ds). In classical mechanics, the formula for work
thus becomes w = F · ds. The pressure is the force acting on
unit area, and the expression for work can be rewritten
w = (P · A) · ds. The change inwork generating volume,
denoted dVw, is directly coupled
to the work, since dVw = A · ds,
meaning we once again
can rewrite the expression for work w = P · dVw.
To translate
work to a more useful quantity, power (
Pw)
is used (where w denotes the power extracted from work).
The amount of work that is carried out at any instant may be expressed in power,
by the expression Pw =
w / t,
where t denotes the time interval. Since the unit
of work is in joules and time is in seconds, power is expressed in joules
over time or, more commonly, in watts.
The low pressure is
compensated with a large piston surface. To feed a large piston a large
volume is needed. To facilitate pressure distribution, this large piston
area is a side parallel with the RS of the REC (c.f. fig.9). In theory,
there is no physical size limitation for the REC; this means that if the
work generating volume increases, more work can be extracted.
If it
wasn’t for the RDL, the stepper motor could easily continue to turn the
RS in any speed even if a heavy work load has blocked the moving boundary,
the piston, from moving. The RS is totally independent of the work load
and is not affected by the conditions of the moving boundary supposed to
deliver the work. That is why the dynamic link is needed to control the
stepper motor of the RS. The Dynamic Link keeps track of the RS angle and
the work output piston position and/or flywheel angle as well as its load.
The Revolution Energy Converter Explained - D R A F T -
So far, a thermodynamic
approach to understand and how to get an idea of how the REC might perform.
The description of this revolutionary heat engine on paper is not exciting
enough to show how unique and fabulous the REC really is. To convince the
world, a proof-of-concept or a prototype must be built, to run, test and
proof its capabilities.
At the moment, a simulation helping to calculate
the amount of energy that the work generating volume can absorb on the warm
side as well as a calculation on how much of this absorbed energy can be
dumped on the cold side is ongoing. The work generating volume absorption
of energy on the warm side should balance with the work generating volume
dumping of energy on the cold side. Understanding and calculating this
energy, helps to dimension how thin the
work generating volume should be
as well as the thickness of the fins.
A simpler “demonstrator” has been built to visually demonstrate the concept
while searching for ways to fund the building of an advanced prototype that
will verify expectations. The demonstrator
uses only three fins (hot
and cold) for the heat transfer in and out of the work generating volume of
the RS in two layers (pic. 1). There is a valve and an analogue pressure meter
(pic.2) to test and make sure that the volume is closed and tightly sealed.
Picture 1: A two-layer revolving shutter RS with cut out quarter openings to carry the work generating volume
Picture 2: The Revolution Energy Converter demonstrator. A theoretical 3D model can be seen at the right in the picture to indicate the placement of the hot and cold fins.
Picture 3: The "Revolving Dynamic Link" control system
Picture 4: Sealing cap covering vital parts of the “Revolving Dynamic Link” control system.
These will be replaced by electronic sensors connected to the
“Revolving Dynamic Link” (pic.3) that controls the 2-layer revolving
shutter. The RDL control system is under the sealing cap shown in picture 4.
This very basic demo model has in its first test runs delivered very distinct
pressure pulses already at 30°C temperature difference.
For the first prototypes built, low power stepper motors are considered
and a versatile controller like the Arduino which is a well-known prototyping
tool that can be bought off-the-shelf. A USB downloadable controller
facilitates experimenting. A computer is connected to this, like
the Raspberry PI 3 with a free open development platform for the
“Revolution Dynamic Link” software. The stepper motor totally controls
the revolving shutter that runs freely inside REC independent of power
output, so it is totally relying on feedback data from the powered
application, i.e. “Revolution Dynamic Linking”.
Planned tests for the
prototype are how the heat transfer relates to the speed of the RS and
how the expected pressure variations relate to the revolving speed. These
tests will be done in a series
of temperature spans.
If the
prototype succeeds in delivering useful data in these first tests, the
next set-up will be to measure power output for the same series of temperatures.
Moreover, the same prototype might deliver the following series of tests
consisting of a work generating volume containing a vapour close to its
condensation to understand how a partial phase
shift of a vapour will affect pressure and rotating speed in narrow
temperature spans.
The Revolution Energy Converter Explained - D R A F T -
Return to nilsinside TECHNOLOGYPlease contact Nils Karlberg for any further information or technical
questions about of the REC;
nils@nilsinside.com