Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02488241 2004-11-29
~" , ~1
Method and Device for Convertinct Thermal Enercty into Kinetic Energy
The invention relates to a method for converting thermal energy into kinetic
energy, whereby a medium undergoes the following changes of state in at least
one chamber separated by a displacer:
- compression, preferable isothermal compression, with thermal dissipation in
a
compression chamber
- heat absorption, preferably isochoric heat absorption, in a regenerator
during
passage of the medium from a compression chamber to an expansion
chamber
- expansion, preferably isothermal expansion, with heat supply in an expansion
chamber and dissipation of effective work
heat dissipation, preferably isochoric heat dissipation, in the regeneration
on
returning the medium to the compression chamber.
Furthermore, the invention relates to a device for implementation of the said
method.
Energy cannot be "created" in the sense of new generation. Energy is present
in
nature in a wide variety of forms, but not every existing form of energy can
be
used equally for human needs. The energy contained in wood is very useful for
heating purposes, for example, but is not very suitable for the generation of
light or
cold for the refrigerator, etc.
Although there are almost ideally available forms of energy for very specific
applications, such as for example petroleum for cars, or natural gas for
industrial
heating, the universally applicable form of energy in the mind of humans is
electric
energy. However, it is virtually non-existent in nature in the form that we
know.
That means that an available form of energy must first be converted into
electric
energy in several steps - and with varying degrees of effectiveness. If you
take for
example fossil sources of energy such as coal, natural gas and petroleum,
which
have stored the energy of the sun in chemical form for millions of years, to
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generate electric energy, three conversion processes and the relevant
industrial
plant are necessary. First the stored chemical energy is converted into heat
through combustion. The heat is used to generate high-tension steam, which is
converts the heat into kinetic energy in the steam turbine. The steam turbine
drives the generator in which the kinetic energy is finally converted into
electric
energy.
Each of these energy conversions has a specific degree of efficiency, i.e.
energy
is lost every time and the overall efficiency is accordingly low. For example,
only
some 40% of the energy stored in coal, natural gas and petroleum can be
converted into electric energy. The remaining 60% are lost to use in the form
of
electricity as so-called waste heat.
In other conversion processes, such as e.g. the conversion of chemical energy
in
petroleum into kinetic energy to drive cars, ships, trains or even aircraft,
the
efficiency is no better either, although the conversion chain is shorter.
If you only look at the huge amounts of electricity consumed worldwide, for
instance, you can see what enormous quantities of energy cannot be used and
are lost. The loss of primary energy not usable for conversion into electric
energy
is already a major problem, especially because of the waste of limited
resources,
but the environmental pollution inseparably associated with the conversion of
chemical energy into thermal energy through combustion is a much more serious
problem for future generations, such as climate changes due to greenhouse
gases, as shown by the C02 problem, for example.
Therefore it is not surprising that man has for decades been trying to improve
and
optimise the conversion processes, and also to make use of a part of the waste
heat, such as e.g. in district heating. Use of a part of the waste heat from
thermal
power plants for heating purposes is already a significant contribution
towards
improving the efficiency of conversion. The efforts to convert other forms of
energy, such as e.g. wind energy or solar energy, into electric energy are
also
producing first results.
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Efforts to shorten the conversion chain by applying other conversion processes
and thus to improve the overall degree of efficiency are also very promising.
An
interesting such conversion process has been realised in the Stirling motor.
The
Stirling motor can convert thermal energy directly into kinetic energy without
the
"detour" via steam.
After the steam engine, the Stirling motor is the second-oldest heat engine,
i.e. a
machine that can convert thermal energy into kinetic energy. And although the
Stirling motor has a significantly higher efficiency that the steam engine and
the
carburettor or diesel engine on principle, it has still not become very
widespread.
Whereas the steam engine and the carburettor or diesel motor were constantly
developed further, in order to achieve not only the satisfactory lifetime but
above
all the right performance with considerably improved efficiency, the Stirling
motor
has almost sunk into oblivion. Only recently it has started to receive more
attention
due to its lower environmental burden and independence of the heat source.
However, a great deal of research and development is still necessary for it to
achieve the same degree of "maturity" as the modern steam engine or
carburettor
motor in cars.
Considerable development work is still necessary, for example, to bring the
efficiency of a built Stirling motor up to the efficiency of an ideal Stirling
motor,
which is identical to that of the Carnot process. For a possible mobile use,
work
will have to be invested primarily in increasing the performance and improving
the
dynamic behaviour during rapid load switches.
The most important advantages of the Stirling motor compared with conventional
heat engines, although they still have not been realised satisfactorily due to
this
development deficit, are:
1. it works with any heat source, such as e.g. solar or process heat,
combustion of biomass, landfill gas or other incinerable waste right down to
waste, etc.;
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2. continuous heat supply, i.e. combustion under optimal conditions is
possible, so that the exhaust contains hardly any pollutants;
3. closed cycle - the medium does not have to be renewed constantly;
4. due to the thermodynamically favourable process, very high degrees of
efficiency can generally be expected - even in the partial load range;
5. extremely smooth running and noiseless.
Currently, three different types of Stirling motor are distinguished in terms
of
embodiment: type a, type ~i and type y. These types of Stirling motors differ
primarily in terms of function principle and structural design.
The ideal Stirling process corresponds with a Carnot process and therefore has
a
very high degree of efficiency. In practice, however, exact implementation,
i.e. an
exact copy of the ideal, or rather the theoretical, process is not possible.
In
embodied machines a number of design-related deviations have to be accepted
that have a negative effect on efficiency and performance.
In the Stirling motors designed or built to date, for instance, it has not
been
possible to realise either isochoric heat absorption or isochoric heat
dissipation,
nor isothermal compression or isothermal expansion. The main reasons for this
lie
primarily in the inevitable clearance volumes and the continuous instead of
discontinuous volume change. Piston and displacer are moved by means of crank
drives with flywheels, so that although there is a reversal of motion at the
dead
centres, there is no short standstill as required by the theoretical process.
The three types, the a, Vii, and y motors, correspond with the three basic
design
solutions developed to date in order to imitate the ideal Stirling process as
well as
possible in the embodied machines.
In the a motor, two pistons in separate cylinders are used, whereby one piston
is
arranged in the hot expansion chamber and the other is in the cold compression
chamber. Depending on the step or crankshaft angle, both pistons are either
working pistons and then again displacers.
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The big disadvantage of a motors is the piston packing in the hot expansion
chamber, which greatly limits the lifetime of the motor and for which a
satisfactory
solution has not been found to date. Another disadvantage is the crank drive
with
5 the associated major deviation from the theoretical process and the low
degree of
efficiency.
So far, a number of different cylinder arrangements have been developed, such
as parallel, aligned opposite, parallel opposite, V cylinders or the
Finkelstein
rotation cylinder, etc., which all function in the same way, have the same
weaknesses and the same low degree of efficiency.
In the ~ machine, a piston and displaces are used, whereby both piston and
displaces are arranged in the same cylinder. For the complicated motion of
piston
and displaces, which depending on cycle move towards each other, then again in
the same direction, for example towards the crankshaft, or one is or should be
at a
standstill while the other is moving, complex gears such as e.g. rhombic gears
are
required.
The major disadvantage of ~3 machines, similar to the a machines, is seals
running
dry. Furthermore the motion of piston and displaces, which acts like a crank
drive
despite complex gears, and therefore has dead centres with reversal of motion,
but no real standstill. In the ~i type, the degree of efficiency actually
achieved by
embodied Stirling motors is far removed from the efficiency of the ideal
Stirling
process.
Another major disadvantage of the ~3 machines is the complex sealing system of
the displaces slide rod in the compression piston. Because piston and
displaces
are arranged in the same cylinder, the displaces slide rod runs through the
compression piston.
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A number of different embodiments of the ~i machines have been developed to
date, such as e.g. Rankine-Napie or Philips, without being able to influence
the
disadvantages of the ~i machine.
In the y machine, piston and displaces are arranged in separate cylinders.
This
avoids the complex sealing system for the displaces slide rod in the
compression
piston. In return, the dead volume detrimental to efficiency is increased.
The greatest disadvantages of y machines, as already described for a and ~i
machines, are the dry seals of the working piston. Moreover, the motion of
piston
and displaces caused by the crankshaft drive or crank-like drive, which makes
a
good approximation to the ideal Stirling process impossible in the embodied
machines. Therefore, the y machine also has a significantly poorer efficiency
than
the ideal Stirling process.
Another major disadvantage of y machines is the greater dead volume, which has
an additional negative impact on efficiency, and the relatively low
compression
ratio that can be achieved, so that only modest volume performance is
possible.
In addition to the single-action machines described, double-action Stirling
machines have also been developed and embodied, especially of the a, type, for
example the Franchot Stirling motor. In this motor, a Stirling process takes
place
in the space above the two pistons, but also below each piston, i.e. the two
cylinders always perform two different cycles of two different Stirling
processes at
the same time with the top and bottom of the pistons. Thereby, the two pistons
and their cylinders delimit four variable volumes, which can be regarded as
pairs
constituting two separate a machines. Like in single-action a machines, the
expansion piston and the compression piston must have a phase displacement of
about 90°.
The efficiency of double-action a, machines such as the Franchot Stirling
motor is
not better than that of single-action a machines. The serious disadvantages
and
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problems are also the same. Merely the volume performance can be improved
through compactness.
The Siemens Stirling motor is also known, which embodies the standard
configuration of most stronger Stirling motors with any number of cylinders,
such
as e.g. the 4-95' of United Stirling with a mechanical capacity of approx. 52
kW. In
this embodiment, a number of models have also been developed, such as e.g.
arrangement of the cylinders in a row, in a "U" or "V" shape, in a rectangle
or in a
circle. Although the arrangement of heater, regenerator and cooler in the
Siemens
Stirling motor was chosen in such a way that the piston sealing in the casing
is
located in the cold section, the basic disadvantages of the a machines remain.
Attempts to embody the principle of the Stirling motor with free piston
arrangements or as a circular piston motor, system Wankel, are also known.
None
of these embodiments has resulted in an improvement of efficiency; on the
contrary, in addition to poorer efficiency compared with the a machines, the
disadvantages and problems were only enhanced.
All these various embodiments of Stirling motors have the additional
disadvantages due to the clearance volumes in heat exchangers, regenerators
and return-flow pipes in common, which additionally lower the pressure ratio
and
thus the efficiency.
The aim of the invention is to create a method of the type set out above, that
on
the one hand avoids the above disadvantages and on the other hand makes it
possible for the first time to embody a Stirling motor in such a way that its
mode of
action can be approximated to the ideal Stirling process much better than
before.
Said object is fulfilled by the invention.
The method according to the invention is characterised by the fact that the
medium flows back and forth between at least two enclosed chambers, whereby
to release effective work the medium is guided through a machine between the
chambers, whereby heat absorption takes places before the machine and heat
CA 02488241 2004-11-29
dissipation takes place after the machine, and that the medium is compressed
in
the chamber after heat dissipation, and that by means of a displacer it
subsequently flows from one side through the regenerator to the other side of
the
displacer, whereby the flow of the medium is controlled using control units,
in
particular valves, and every displacer is moved by a drive. With this
invention it is
for the first time possible to achieve a significantly higher efficiency than
with any
other embodiments of Stirling motors to date.
The higher efficiency is due primarily to the better approximation of the work
process described to the theoretical cycle process, which is achieved with the
method of the invention. Due to the temperature difference of the medium in
the
two coupled chambers and the resulting pressure differentials, it flows into
the
cold chamber and thereby performs work through a work machine. The resulting
compensation state is due to the fact that the greater part of the medium is
in the
cold chamber. In the subsequent isochoric regenerator cycle, with heat supply,
the
pressure differential builds up inversely between the two chambers and is
again
converted into work through the work machine. This behaviour is in analogy to
an
oscillating circuit and with a constant Carnot efficiency it makes a higher
power
density with reference to the volume of medium possible than in the
theoretical,
ideal Stirling process.
In a special embodiment of the invention, the chamber is separated into a
double-
action chamber by the displacer. Thus, the process can be speeded up, since
return-flow pipes are not required. Moreover, seals against any bufFer space
otherwise required are dispensed with.
In accordance with a special feature of the invention, each displacer is moved
by a
separate drive. In accordance with this feature of the invention, there are no
crank
drives or crank-like drives, which are mainly responsible for the poor
approximation of the embodied processes to the ideal Stirling process. Instead
of
the crank drives, a linear drive is used that can be controlled independently
from
other movements, so that any number of standstill times of any length can be
achieved in the displaces for example.
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In accordance with another embodiment of the invention, the displacers in the
coupled chambers are moved by a drive via a rigid connection. This allows for
a
simple design, whereby for example two hot and two cold chambers are coupled
with each other. This allows complete immersion of the hot-hot chambers in the
heat source, and immersion of the cold-cold chambers in the cold source,
without
suffering losses through heat conduction between warm and cold source medium.
The two displacers are connected by a rigid slide rod that absorbs the forces
acting between the displacers. To move the displacers, only the frictional
drag and
flow losses have to be overcome. The regenerators may also be located within
or
outside the slide rod. The slide rod itself does not have to be sealed off.
The
theoretical power density with reference to the volume of medium is higher
than in
the ideal Stirling process. This embodiment allows the use of low temperature
for
power generation and for the generation of cold.
In accordance with a special embodiment of the invention, the chamber is
divided
by the displaces into an expansion chamber and a compression chamber,
whereby the medium used for effective work, after exiting the expansion
chamber
through the regenerator allocated to this chamber for dissipation of effective
work
through the work machine and after the work machine, possibly with output of
cold, flows into the compression chamber of the coupled chamber and then
through movement of the displaces flows from the compression side through the
regenerator allocated to this chamber into the expansion chamber of the same
chamber. This embodiment is the so-called "cold" motor. The work machine can
be designed very simply, since it is not subjected to high temperature stress.
Additionally, cold can be generated through expansion of the cold medium
cooled
by the generator, which can be utilised before flowing into the cold workspace
through a heat exchanger. The efficiency and power density is higher than in a
Stirling motor of type y that has the piston flanged onto the cold side.
In accordance with another embodiment of the invention, the chamber is
separated by the displaces into an expansion chamber and a compression
chamber, whereby the medium used for effective work, after exiting the
expansion
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chamber for dissipation of effective work, possibly through a heater, flows
through
the work machine and subsequently through the regenerator and possibly through
a compressor, possibly through an additional cooler, into the compression
chamber of the coupled chamber, and subsequently through movement of the
displacer flows from the compression side through the regenerator allocated to
this chamber into the expansion chamber of the same chamber. This embodiment
is the so-called "hot" motor. The theoretical efficiency of this type is close
to that of
the Carnot efficiency, the theoretical power density with reference to the
volume of
the medium is higher than in the ideal Stirling process.
In accordance with yet another embodiment of the invention, the chamber is
divided by the displacer into two expansion chambers and compression chambers
each, whereby the medium used for effective work, after exiting an expansion
chamber through the regenerator allocated to this chamber for dissipation of
effective work through the work machine and after the work machine flows into
the
compression chamber of the coupled chamber and then through movement of the
displacer flows from the compression side through the regenerator allocated to
this chamber into the other expansion chamber of the same chamber. As already
mentioned, this "low temperature" motor allows low temperature to be utilised
both
for power generation and for the generation of cold.
In accordance with another special embodiment of the invention, heat
absorption
is isobaric, in particular immediately before the work machine. The major
advantage must be seen in the fact that the temperature in the displacers is
limited to the maximum regenerator temperature, whereby the regenerator
temperature is lower than the heater temperature.
In accordance with an advantageous embodiment of the invention, compression is
achieved by pressure equalisation and/or by a compressor. If compression is to
be
achieved solely by means of pressure equalisation, one rotating machine, i.e.
the
compressor, can be dispensed with. This certainly makes the process simpler.
If a
compressor is integrated, an even higher efficiency is achieved.
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It is also an object of the invention, however, to provide a device for
implementation of the said method.
The device for implementation of the method in accordance with the invention
is
characterised by the fact that at least two enclosed chambers are provided,
whereby each chamber is divided into two sections by a displacer which can be
moved by a drive, whereby one section contains a heater and the other section
a
cooler, and each chamber has a regenerator allocated to it, whereby both
sections
are connected to this regenerator, and that at least one section of each
chamber
is connected to a work machine, whereby the section used for subsequent
dissipation of effective work is connected to the corresponding section of the
other
chamber, and that control units, in particular valves, are provided to control
the
medium. As already mentioned above, a higher power density is achieved with
the
device in accordance with the invention.
Another advantage of the device in accordance with the invention must be seen
in
the fact that the machine can be operated with a low clock speed. The chambers
have no real piston seals and thus circumvent the sealing problem, which
occurs
particularly at greater piston volumes. By eliminating this problem, large-
volume
chambers can be used, which can be operated at low clock speeds and
discontinuously. Thus, an approximation to the ideal Stirling process is
achieved.
With the lower clock speed and thus longer heat transition time than in
conventional Stirling motors, isothermal processes can be realised better. The
large heat transition surfaces in the chambers accommodate the use of biomass
fuels.
Another advantage is found in minimisation of the clearance volume. The
clearance volume is the volume not involved in the thermodynamic process,
which
as a result has a detrimental effect on efficiency. It is produced virtually
through
sinus movement of the piston, and in real terms by the volume of the
regenerator,
the heater pipe, etc., through which the medium flows. The ratio of large-
volume
chambers and by comparison small-volume elements such as work machine,
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regenerator, heater and cooler results in a favourable ratio between clearance
volume and work volume, and is a significantly lower than that of the machines
currently embodied.
The minimisation of drive forces is also advantageous. They are made up of the
flow resistance of pressing the medium through between the chambers
isochorically, activating the valves, and possibly compression of the medium
by a
compressor. One of the main components, friction of the dry-running piston
sealing rings together with friction of the crank drive, is eliminated.
In summary it can therefore be said that through the elimination of moving
seals
that are under temperature stress and run dry, which were the main problem to
date, it is possible to produce this motor in standard mechanical engineering.
The
separation of chamber and work machine allows the use of standard machine
elements. Due to the rapidly rotating work machine, the generator has a
smaller
rated size. Elimination of the mechanical drive unit also simplifies the
design. The
displacer does not have to be synchronised with the work machine, the optimal
work points can be set separately from each other.
In accordance with a special feature of the invention, at least one control
unit, in
particular a valve, is provided in the connections between the work machine
and
the individual sections. It serves to uncouple the work cycle and the
regenerator
cycle. Instead of control via valves, slit control could also be used.
In accordance with another special feature of the invention, four, six or more
even-
numbered chambers are provided, whereby the chambers are always coupled in
pairs. With the increasing number of coupled chairs, the process-related
waviness
at the work machine is reduced and the regenerator cycle can be extended by
comparison with the work cycle.
In accordance with a very special feature of the invention, the work machine
is a
turbine, in particular an axial, radial or Tesla turbine. The use of turbines
allows
the elimination of moving seals subject to temperature stress and running dry,
which are the main problem in Stirling motors driven by pistons. With the disk
or
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Tesla turbine, in particular, better isothermal expansion or compression is
possible.
In accordance with one embodiment of the invention, the work machine is a
piston
motor. This embodiment has the advantage that it is cheap and can be build
using
standard components.
In accordance with a further embodiment of the invention, the work machine is
a
screw motor. Like the turbines, the screw motor has the advantage of
eliminating
seals.
In accordance with a special embodiment of the invention, the drive for the
displacer is a linear drive. The linear drive guarantees accurately
controllable
acceleration and braking of the displacer. This makes discontinuous movement
in
accordance with the ideal thermodynamic process possible with low losses. All
passages and thus seals for rods or crank drive can thus be eliminated. A
possible
rapid power control is possible instantaneously by changing the displacer
clock
speed and does not have to be induced by changing the upper temperature. Thus,
very good control is possible in the partial load range.
In accordance with another feature of the invention, a heater is included
upstream
and/or downstream from the regenerator. The heater supplies energy to the
medium in addition to the heater head in the chamber, thus enlarging the total
absorption surface in the hot area.
A special embodiment of the invention is characterised by the fact that the
chamber is divided by the displacer into an expansion chamber and a
compression chamber, that the expansion chamber is connected to the
regenerator allocated to this chamber and the regenerator is connected to the
work machine, that the outflow side of the work machine is connected to the
compression chamber of the coupled other chamber, and this compression
chamber is connected to the expansion chamber of the same chamber by the
regenerator allocated to this chamber, whereby one control unit each, in
particular
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a valve, is provided between regenerator and inflow side of the work machine,
and
outflow side of the work machine and compression chamber. Here the same
advantages apply accordingly, as already described above for the "cold" motor.
Another special embodiment of the invention is characterised by the fact that
the
chamber is divided by the displacer into an expansion chamber and a
compression chamber, that the expansion chamber is connected to the inflow
side
of the work machine and the outflow side of the work machine is connected to
the
compression chamber of the coupled other chamber through the regenerator and
possibly through a compressor, and this compression chamber is connected to
the
expansion chamber of the same chamber through the regenerator allocated to
this
chamber, whereby one control unit each, in particular a valve, is provided
between
expansion chamber and inflow side of the work machine, and outflow side of the
regenerator and compression chamber. Here the same advantages apply
accordingly, as already described above for the "hot" motor.
An alternative embodiment of the invention is characterised by the fact that
the
chamber is divided by the displacer into two expansion chambers and two
compression chambers, that each expansion chamber is connected to the inflow
side of the work machine through a regenerator and the outflow side of the
work
machine is connected to the compression chamber of the coupled other chamber,
and this compression chamber is connected to the expansion chamber of the
other chamber through a regenerator, whereby one control unit each, in
particular
a valve, is provided between the regenerator downstream from the expansion
chamber and the inflow side of the work machine, and the outflow side of the
work
machine and the compression chamber. Here the same advantages apply
accordingly, as already described above for the "low-temperature" motor.
Naturally, the hot gasses could also be expanded, in accordance with the work
principle of the hot motor.
Another embodiment of the invention is characterised by the fact that a heater
is
provided in flow direction after the section connected to the work machine.
This
CA 02488241 2004-11-29
allows the work machine to achieve higher temperatures, which result in a
better
power yield.
In accordance with an advantageous embodiment of the invention, the heater is
5 locally separated from the section, for example in the combustion chamber of
a
heating boiler. Thus, only the elements used as heater are subject to highest
temperature stress, so that only these parts have to be dimensioned
accordingly.
The invention is explained in more detail based on the design examples
illustrated
10 in the figure.
The figures show:
Fig. 1 the device for transformation of thermal energy into kinetic energy as
a hot
15 motor,
Fig. 2 the device as a cold motor,
Fig. 3 the device as a low-temperature motor,
Fig. 4 an embodiment of the device with locally separated heaters, and
Fig. 5 schematics of the mode of action of a device.
By way of introduction, it is noted that in the described embodiment the same
parts and the same states are allocated the same reference numbers and the
same component names, whereby the disclosures contained throughout the
description can be applied by analogy to the same parts and the same states
with
the same reference numbers or same component names.
As shown in Fig. 1, the device using a medium for conversion of thermal energy
into kinetic energy has two enclosed chambers 1, 2, whereby each chamber 1, 2
is divided by a movable displacer 3, 4 into two sections, namely an expansion
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chamber and a compression chamber. Each displacer 3, 4 can be moved by a
drive, in particular by a linear drive 5. Each chamber 1, 2 has a regenerator
6, 7
allocated to it. Both sections of the chamber 1 resp. 2 are connected to this
regenerator 6 resp. 7 by pipes 8, 9 resp. 10, 11.
One section - the expansion chamber in this case - of each chamber 1 resp. 2
is
connected to a work machine 12. The expansion chamber of chamber 1 used for
dissipation of effective work is connected to the corresponding section - i.e.
the
compression chamber- of chamber 2 after the work machine 12.
To control the medium control units, in particular valves 13, are provided,
which
are arranged between the work machine 12 and the individual sections of the
chamber 1 resp. 2. Slit control could also be used instead of the valves 13.
As the work machine 12, a turbine, in particular an axial or radial turbine,
can be
used. Naturally, a piston or screw motor is also possible as work machine 12.
The
work machine 12 is connected to the generator 18 by a shaft 17.
In the ideal process, the medium undergoes the following changes of state:
- isothermal compression with thermal dissipation in a compression chamber
- isochoric heat absorption in a regenerator 6 resp. 7 during transition of
the
medium from the compression chamber to the expansion chamber
- isothermal expansion with heat supply in an expansion chamber and
dissipation of effective work
- isochoric heat dissipation in the regenerator 6 resp. 7 during return flow
into
the compression chamber.
Generally, it can be shown that the medium flows back and forth between the
two
double-action enclosed chambers 1, 2. To release effective work, the medium is
guided through a work machine 12 between the chambers 1, 2. Subsequently, the
medium flows in the double-action chamber 1, 2 by means of the displacer 3
resp.
4 from one side through the regenerator 6 resp. 7 to the other side of the
displacer
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3 resp. 4, whereby the flow of medium is controlled via the valves 13 and each
displacer 3, 4 is moved by a drive 5.
As already mentioned, Fig. 1 shows the device, also referred to as 4-quadrant
turbine, as a "hot" motor, since the medium is guided through the work machine
12 in its highest temperature state. The expansion chamber is connected to the
inflow side of the work machine 12 and the outflow side of the work machine 12
is
connected to the regenerator 6 resp. 7 and through a compressor 19 to the
compression chamber of the coupled other chamber 2. This compression
chamber is connected to through the regenerator 7 allocated to this chamber 2
with the expansion chamber of the same chamber 2, whereby one valve 13 each
is provided between the expansion chamber and the inflow side of the work
machine 12, and the outflow side of the regenerator 7 and the compression
chamber.
The regenerator 6 resp. 7 consists of a heater 14, a coupled regenerator 15,
and
a cooler 16, whereby the expansion chamber is connected to the heater 14 and
the compression chamber is connected to the cooler 16. Moreover, the
regenerator 6 resp. 7 is divided vertically into individual sectors. These
sectors are
sealed off against each other. In the inner sectors the medium flows from the
work
machine 12 to the compressor 19, and the outer sectors serve for the
regenerator
cycle of the medium.
The expansion chamber is connected to the heater 14 of the regenerator 6
allocated to this chamber 1, and the regenerator 6 is connected to the work
machine 12. The outflow side of the work machine 12 is connected through the
cooler 16 with the compression chamber of the coupled other chamber 2, and
this
compression chamber is connected through the regenerator 7 allocated to this
chamber 2 with the expansion chamber of the same chamber 2. A valve 13 each
is provided between the regenerator 6 resp. 7 and the inflow side of the work
machine 12; and the outflow side of the work machine 12 resp. compressor 19
and the compression chamber.
CA 02488241 2004-11-29
18
Fig. 2 shows the 4-quadrant turbine as a "cold" motor. The chamber 1, 2 is
again
divided by the displacer 3, 4 into an expansion chamber and a compression
chamber.
In this case, the medium used for efficient work, after exiting the expansion
chamber, flows through the regenerator 6 allocated to this chamber 1 to
release
effective work through the work machine 12, and after the work machine 12 into
the compression chamber of the coupled chamber 2. Subsequently, the medium,
through movement of the displacer 4, flows from the compression side through
the
regenerator 7 allocated to this chamber 2 into the expansion chamber of the
same
chamber 2.
Fig. 3 shows the device as a low-temperature motor. Thereby, the displacer 3,
4 is
moved in a rigid connection 20 by a drive 5. The chamber 1, 2 is divided by
the
displacer 3, 4 into two expansion chambers and two compression chambers each.
Each expansion chamber in chamber 1 is connected through a regenerator 6, 7
with the inflow side of the work machine 12, and the outflow side of the work
machine 12 with the compression chamber of the coupled other chamber 2. This
compression chamber is connected through the regenerators 6 resp. 7 with the
expansion chamber of the other chamber 1, whereby one valve 13 each is
provided between the regenerator 6 resp. 7 downstream from the expansion
chamber and the inflow side of the work machine 12, and the outflow side of
the
work machine 12 and the compression chamber.
The medium used for efficient work, after exiting an expansion chamber, flows
through the regenerator 6 resp. 7 allocated to this chamber 1 to release
effective
work through the work machine 12, and after the work machine 12 into the
compression chamber of the coupled chamber 2. Subsequently, the medium,
through movement of the displacer 3 resp. 4, flows from the compression side
through the regenerator 6 resp. 7 allocated to this chamber 2 into the
expansion
chamber of chamber 1.
To cool chamber 2, it can be arranged under the earth for example.
CA 02488241 2004-11-29
1~9
Moreover the displacers 3 resp. 4 can also be designed as coupled membranes.
In Fig. 4, each chamber 1, 2 is divided by the displaces 3, 4 into one
expansion
chamber and one compression chamber. Each displaces 3, 4 can be moved by a
drive, in particular by a linear drive 5. Moreover, each displaces 3, 4 is
arranged in
a guide 22. Each chamber 1, 2 has a regenerator 6, 7 allocated to it. Both
sections of the chamber 1 resp. 2 are connected to this regenerator 6 resp. 7
by
pipes.
Moreover the expansion chamber is equipped with an intermediate heater 21.
This
intermediate heater 21 can be designed as a layered intermediate heater 21 or
in
the form of lamella packages. The compression chamber is equipped with a
cooler 16.
The expansion chamber can possibly be connected through the intermediate
heater 21 to a locally separated heater 14. The heater 14 could be arranged in
a
heating boiler. Isobar heating takes place in this heater 14. The medium flows
from heater 14 through the work machine 12. The work machine 12, preferably a
Tesla turbine, is coupled to generator 18 by a direct shaft 17.
The process is illustrated once more in summary. The compressed medium flows
from the compression chamber of chamber 1 through the allocated regenerator 6
and intermediate heater 21 into the expansion chamber of the same chamber 1
and is thereby heated isochorically. The passage is actuated by movement of
the
displaces 3. After exiting the expansion chamber of chamber 1, the medium
flows
through the external heater 14, in which isobaric heat absorption takes place,
to
the work machine 12.
From the work machine 12, the medium flows through the regenerator 7 and the
cooler 16 into the compression chamber of chamber 2 and is compressed
isothermally by subsequent flow or by a compressor. The compression heat is
dissipated in cooler 16 of chamber 2. Through movement of the displaces 4 in
CA 02488241 2004-11-29
chamber 2, the compressed medium is passed through the regenerator 7 and the
intermediate heater 21 into the expansion chamber of chamber 2.
After exiting the expansion chamber of chamber 2, the medium flows through the
5 external heater 14, in which isobaric heat absorption takes place, to work
machine
12. From work machine 12, the medium flows back to the compression chamber
of chamber 1.
In principle, the medium flows in a figure of eight, whereby the work machine
12 is
10 provided as the centre. The individual process steps are controlled by the
relevant
valves - not shown.
Fig. 5 describes the mode of action of the device with valve control based on
a
real example. In chamber 1 with displacer 3, the medium has a temperature To
of
15 530°C and a pressure Po of 30 bar. In chamber 2 with displacer 4,
the
temperature Pu is 30°C and the pressure Pu is 10 bar. Due to the
pressure
differential created in the displacer cycle between chamber 1 and chamber 2,
valve 23 and valve 24 opens in flow direction. The hot medium with a
temperature
of 530°C flows out of chamber 1 through valve 23 into the heater, where
it is
20 overheated to 630°C and then returned to 530°C through
polytropic relief in the
work machine 12. Subsequently, the medium flows through valve 24, the
regenerator 7, where it is cooled to 60°C, the cooler 16, where it is
cooled to 30°C,
to chamber 2. The valves 25 and 26 block the pressure differential and are not
opened until after the subsequent regenerator cycle, i.e. in the next work
cycle.
The regenerator cycle starts after the work cycle has produced pressure
equalisation between the chambers 1,2; i.e. the pressure is the same
throughout
the system (mean pressure). The displacers 3, 4 now move into the opposite
dead
centre positions and thereby displace the medium through the regenerator-
cooler
unit to the other side of each displacer 3, 4. The isochoric heating resp.
cooling of
the medium that takes place thereby effects a change of pressure in the
relevant
chamber 1, 2; i.e. when cold is passed into hot, a pressure increase is
effected,
when hot is passed into cold a pressure reduction is effected. The regenerator
CA 02488241 2004-11-29
21
cycle is thus ended and the pressure differential used for the subsequent work
cycle.
In conclusion, it must be pointed out that for better legibility the
individual
components and assemblies in the drawing are not shown proportionally or to
scale.
