EP1454051A1

EP1454051A1 - Thermohydrodynamic power amplifier

Info

Publication number: EP1454051A1
Application number: EP03752650A
Authority: EP
Inventors: Jürgen KLEINWÄCHTER; Eckhart Weber; Olivier Paccoud
Original assignee: Colsman-Freyberger Claus
Current assignee: POWERFLUID GMBH
Priority date: 2002-09-02
Filing date: 2003-08-20
Publication date: 2004-09-08
Anticipated expiration: 2023-08-20
Also published as: AU2003266179A1; NO20051185L; BR0314462A; DE10240924A1; DE50300228D1; ES2236677T3; CN100412346C; WO2004022962A1; CA2497603A1; TR200500719T2; DE10240924B4; JP2005537433A; ATE286204T1; KR20060111356A; CN1708638A; EP1454051B1; ZA200501785B; MXPA05002392A; US20050268607A1

Abstract

A thermodynamic force amplifying machine that causes a liquid working medium to perform useful work in a three-stroke working cycle (isochoric heating, isothermal expansion, contraction through regenerative cooling) making use of an external heat source and of an external cold source. The work performed by the auxiliary drive ( 12 ) at the displacer ( 11 ) is thereby much smaller than the one produced in the conversion system ( 18, 19 ) (force amplification). An inversely operating machine driven by an external power source acts as a heat pump/refrigerator.

Description

Thermo - hydrodynamic booster

Liquids are practically incompressible compared to gases, have a smaller, heat-related increase in volume, significantly higher specific heat capacities and offer the possibility of exchanging heat better. The attempt to use liquids in heat engines as an alternative to working gas was undertaken in the mid-1920s by J. F. Malone from Newscastle-on-Tyne (England).

He developed a regenerative machine similar to the hot gas Stirling machine, but which is filled with pressurized water as the working medium instead of air. (U.S. Patent 1,487,664 of March 18, 1924 and U.S. Patent 1,7717,161 of June 11, 1929).

He was able to prove that he achieved an efficiency of 27% at a temperature difference of 305K, which corresponds to a remarkable degree of implementation of 54% of the ideal Carnot cycle and was about twice as high as that of the steam engines common at the time.

The reason for this good efficiency was due to the fact that the machine, like the Stirling machine, had a heat generator and also used the heat transfer properties of the liquids, which are significantly better than gases. In Fig. 1 the Malone machine is shown schematically. Thereby (1) the working cylinder, (2) the displacement cylinder, (3) the heater which is continuously heated by the external (flame) heat (3a), (4) the cooler, (5) the displacement piston, which is the regenerator ( 2a) 90 ° out of phase with the working piston (6) from hot to cold. The working piston (6) connected to the flywheel (7) via the connecting rod (7a) transmits the phase-shifted oscillating movement to the regenerator section (2a) via the auxiliary connecting rod (8a) and the eccentric (8).

In Fig. 2, both an ideal Stirling cycle (10) and the cycle (9) realized by the Malone machine are shown in the PV diagram.

Since water only remains liquid at very high pressures of> 100 bar in the required working temperature range, Malone had to use very pressure-resistant cylinders. Since he also used crankshafts and working pistons to convert the pressure fluctuations thermally generated in the liquid into rotating shaft energy, he subjected the liquid to a working cycle, as is customary in classic work machines, in which, in principle, during the (hot) expansion phase over the working work and the crankshaft flywheel system are given useful work, while in the (cold) recompression phase work has to be put into the system that comes from part of the expansion work stored in the flywheel.

Since liquids are almost incompressible compared to gases or liquid-vapor mixtures, it is inevitable that the rigid piston, the working piston, displacer, crankshaft and flywheel impress the fluid, especially during the recompression phase, extremely high pressures are generated. This leads to very high alternating pressure loads and requires very heavy flywheels, which in turn transmit strong dynamic loads to the bearings and the overall structure.

The basic advantages of the Malone machine (compared to gases, significantly better heat transfer properties, high heat capacity and thus power density) were counteracted by the pressure fluctuations that limit the resulting service life. This is also the reason why this machine was not used in daily use despite superior thermodynamics.

The object of the present invention is therefore to use the fundamental advantages of liquids as thermodynamic working media, already recognized by Malone, in a technically novel construction in such a way that the negative aspects described no longer occur.

The machine according to the invention described below acts as a thermo-hydrodynamic power amplifier (THK).

In the PV diagram (Fig. 3), the THK goes through a fundamentally different cycle than classic heat engines. The liquid is heated isochorically from a to b. The initial pressure Po corresponds to the ambient pressure (or a slightly higher pressure). As soon as the desired pressure Pl is reached in the liquid, a shut-off element (17) opens and the liquid expands by working on a downstream system (hydraulic motor, compressor piston, etc.). This relaxation occurs until the initial pressure Po is again reached at a larger volume and higher temperature than the initial state a at c. In contrast to classic machines, in which the fluid is brought back to the initial state a by mechanical back compression, the contraction of the liquid is brought about by heat extraction in the THK. According to the invention, this has the great advantage that since all useful energy is withdrawn from b to c during the expansion phase, no mechanical energy has to be temporarily stored in any way (flywheel, wind boiler, etc.). This principle also lies, as explained below , the possibility according to the invention of a crankshaft mechanism, with the constraining forces exerted by it on the fluid, can be completely dispensed with.

If a regenerator or recuperator is also included in the heat exchange process during work phases a → b and c - _* a and the expansion of the fluid is isothermal, the work process defined by the key points a, b, c is the exception of irreversible losses in the fluid and heat loss thermodynamically ideal.

4 shows the basic configuration of a THK in combination with a hydraulic motor.

(11) is the displacement piston which is moved up and down by a linear drive (12) inside the pressure cylinder (13). It periodically displaces the working fluid back and forth via a heater (14), regenerator (15) and cooler (16). A hydraulic valve serves as a switchable shut-off element (17). This is closed at the beginning of the cycle (Fig. 3, section a → b) when the displacer moves down and thus transports the liquid to the hot side of the system. When the desired pressure Pi in point b of the PV diagram is reached, the valve opens and the liquid expands at high pressure with the work being carried out by the hydraulic motor (18) with the flywheel (19) coupled. The relaxed fluid then collects in the collecting vessel (20). A circulation line with the check valve (21) ensures that the fluid circulates continuously from the collecting vessel through the hydraulic motor as long as it is rotating. When the work-supply expansion of the fluid (point c in the PV diagram, FIG. 3) has ended, the valve (17) is closed, the displacer (11) moves upward and displaces the fluid on the cold side of the system (Distance c → a in Fig. 3). The cooling fluid contracts to the starting point a of the cycle (Fig. 3) and sucks in fluid via the line (22) and the check valve (23) from the collecting vessel (20).

Since the regenerator (15) is flowed through in alternating directions by the hot and cold fluid, it temporarily stores heat almost without loss of entropy (because heat and cold are recovered along a linearly increasing temperature profile) and releases it back to the fluid at the right time.

With a suitable choice of the oscillation frequency of the displacer (11) and the correct dimensioning of the flow cross sections through the heater, regenerator. Cooling section is achieved that the amount of work given off by the expanding liquid is many times higher than that of

Displacement piston work done. For this reason and because of their mode of action we call them Machine according to the invention thermo-hydrodynamic power amplifier (THK).

For better understanding in FIGS. 4a, 4b, 4c, the three work cycles are again shown schematically and assigned to the respective section in the PV diagram. Thereby - »represents the fluid flow under pressure, _* pressurized fluid without movement, - → fluid movement with low pressure.

In Fig. 4a the fluid is compressed isochorically. The displacement piston (11) driven by the linear drive (12) is on its way down. The hydraulic valve (17) is closed. The route a -> • b is traveled in the PV diagram. The fluid level in the expansion vessel (20) is at its lowest level.

In Fig. 4a the fluid is compressed isochorically. The displacement piston (11) driven by the linear drive (12) is on its way down. The hydraulic valve (17) is closed. In the PV diagram, the route a → b is covered. The fluid level in the expansion vessel (20 is at its lowest level.

In Fig. 4b, the displacement piston (11) has reached bottom dead center. The linear drive (12) stands. The hydraulic valve (17) has opened. The route b → c is traveled in the PV diagram. The hydraulic motor (18) is driven by the relaxing liquid. The fluid level in the expansion tank (20) increases.

4c, the displacement piston (11) moves upwards through the linear drive (12). The hydraulic valve (17) is closed. The unpressurized hot fluid is cooled back to the initial temperature via the regenerator (15) and cooler (16) and thus experiences a contraction. The resulting vacuum draws fluid out of the expansion vessel (20) via the line (22). Its level drops to its lowest value. The route c → a is traveled in the PV diagram. This means that the initial state a of the cycle is reached again.

The basic principle of a three-stroke THK machine described so far can be varied in different ways. One possibility according to the invention is to use the pressure build-up by the hydraulic motor (18) itself instead of the hydraulic valve (17). This is due to the fact that the swallowing volume of the hydraulic motor (18) is selected so that it is significantly smaller than the volume flow of the fluid that results from the heating of the fluid on the section a - * ^■ b in the PV diagram. FIG. 5 shows a PV diagram resulting from such a THK process. The process is started again according to the invention when the fluid is in the pressure state P ₀ . The medium that expands by moving the fluid from cold to hot flows through the hydraulic motor (17) under increasing pressure until at P'i at b the displacement piston (11) has reached its bottom dead center. The fluid then relaxes with the displacer piston held at point c at P ₀ , and is then contracted by regenerative cooling from c - → a. The hydraulic valve (17) is closed during cycle part a → b → c and opened from c → b.

Such a variant of the THK cycle achieves lower outputs per cycle, but is characterized by a particularly smooth, continuous run and requires less pressure resistance due to the lower maximum pressure.

A further advantageous embodiment is the combination of the shut-off properties of the hydraulic valve (17) and the hydraulic motor. 6 shows the indicator diagram of such a THK variant. Starting from the initial pressure P ₀ , the fluid is isochorically compressed (valve 17 is closed) to the intermediate pressure Pi. From b to b 'the fluid relaxes isobarically via the hydraulic motor (18) (valve 18 is open). After the displacement piston (11) has reached its bottom dead center, the fluid relaxes from b 'to c (valve 18 is open). Then, with the valve 18 closed, the fluid is again contracted from c to the initial state a by reversible heat removal. Such a variant of the TJHK achieves good cycle performance and is gentle on the pressure cylinders because of the lower maximum pressure compared to the basic variant.

Another advantageous embodiment of the THK according to the invention consists in the possibility of integrating the heater (14) and the cooler (16) into the fluid circuit only during the work cycle sections during which their respective function is required. On the one hand, this minimizes the negative effects of fluid dead volumes and, on the other hand, enables the pressure flow cross sections through the heater and the cooler to be designed without negative effects on the cycle with regard to a low dynamic flow resistance and optimal heat transfer properties. In Fig. 7 the corresponding, necessary by-pass lines with shut-off valves and their temporal use are shown schematically on the basis of the PV diagram.

While the fluid is displaced from a → b through the displacement piston, that is to say the fluid is heated, it is undesirable to remove heat via the cooler (16). By closing the valves 24a, 24b, the fluid is directed around the cooler in a by-pass (24c) and then flows through the regenerator (15) and heater (14). In the subsequent expansion of the fluid from b → c, cooling is again undesirable (24a, 24b still closed, fluid flows through 24c).

The reheating by the heater (14) is due to the desired isothermal relaxation of b → c desired. The fact that the fluid flows from a → b → c through the bypass 24c is marked in the PV diagram. If the fluid is subsequently reversibly cooled from c - → a and thereby contracts, only the effect of the cooler (16), but not that of the heater (14), is desired. For this reason, the heater is now shut off via the two valves 25a, 25b and the fluid is directed via the bypass 25c directly through the regenerator (15) and cooler (16) (valves 24a, 24b opened again). The bypass lines 24c and 25c are provided with check valves 24d and 25d so that the fluid flows through (16) and (14) when the shut-off valves 24a, 24b and 25a, 25b are open.

So far, THK machines with rotation decoupling by the hydraulic motor have been described. Since the cycle energy decreases steadily in the course of the expansion of the working fluid, it is necessary to "conform" to this unstable range of services. In the case of rotating machines, this is best done using a corresponding flywheel (19).

The fact that on the one hand energy is only released to the outside during the expansion phase and on the other hand the working frequency of the THK machine should be as low as possible for reasons of efficiency, means that the flywheel, in addition to the described conformity of the unstable energy supply during expansion, is also relative long periods during which the machine does not release any energy must bridge. This naturally leads to large flywheels.

Therefore, a further embodiment of the THK machine according to the invention is to design it as a multi-cylinder machine (number n of cylinders> 2) and to control the timing of the linear drives (12) of the various cylinders in such a way that the resulting cycle overlap to a smoothed drive torque leads. This leads to much smaller flywheels.

According to the invention, however, the purely translatory movement of the expanding and contracting liquid column is also used to drive subsystems such as typically: air compressors, heat pump refrigeration machines, compressors, reverse osmosis systems and the like.

FIG. 8 shows such a THK machine according to the invention with linear force decoupling and a linear conformer. Since the subsystems in this case require a fixed working piston (instead of the "liquid" working piston described so far), the advantageous embodiment of this variant of the object according to the invention is due to the integration of the working piston (26) in the pressure cylinder (13) and the the air cushion (27) underneath the working piston makes the expansion vessel (Fig. 3, 26) unnecessary. tig. The working piston, which in this case also periodically moves downward during the expansion phase under the application of force, is held by the switchable shut-off element (29), which in this case is advantageously designed as a shoe brake which engages around the piston rod, until the desired maximum pressure (in the PV Indication diagram point b) is reached. The force is then decoupled via the force KoiüOrmator (30), which is designed geometrically as a parallelogram. The parallelogram is provided with swivel joints in its four corners, which cause its shape to change constantly due to the imprinted movement (indicated by 30, 31). If you now couple the piston rod of the desired subsystem to be operated with linear force at a corner point whose axis is perpendicular to the axis defined by the working piston, the force-effect of the working piston of the THK, which is due to the isothermal relaxation of b -> c is asymptotic, conformal, that is, even over the entire working stroke. Since the THK only releases mechanical work to the outside world during expansion, the working piston of the subsystem is only positively connected via the piston rod (33) during expansion, ie it is only "pushed" by the conformer and sits on the separation point (33a) loose on it (pressure-less coupling).

According to the invention, this type of THK can also be operated with the cycle variants shown in FIGS. 5 and 6 and described in the text, and can be optimized with the “by-pass” arrangements shown in FIG. 7.

Since the THK represents a reversible thermodynamic machine, there is a particularly advantageous variant according to the invention in its configuration as a refrigerator heat pump.

Such a THK machine is shown in FIGS. 9a, 9b, 9c, each with the corresponding work steps during the three work phases of the driving THK machine and the driven THK refrigerating machine heat pump.

The driving THK machine basically has the same structure as that shown in Fig. 8 and described in the previous text. The conformer mechanism (30) pushes the working piston (26a) of the driven refrigeration machine and heat pump into the cylinder (13a) periodically and out of phase with the drive machine due to the pressure-free coupling (33a), which is also described. According to the invention, the refrigeration machine basically has the same elements as the working mask, which are therefore identified by the same number and the index a (14a = heater, 15a = regenerator, 16a = cooler, Ila = displacer, 12a = displacement piston linear drive, 29a = switchable shut-off element). In Fig. 9a, the phase-shifted work cycles of the TΗK work machine (line) and the IHK refrigeration machine (- - - - Line) shown to the left of Fig. 9a to Fig. 9c, only the corresponding work cycles of the working machine and the refrigeration machine for the three main work cycles are shown. The drawings below give information about the position, direction of movement or standstill of the working piston and displacer piston of both machines ( 26, 26a, 11, 11a) and the state of the switchable shut-off elements (29, 29a). With the latter, ≡ 0 = closed, ≡ 1 = open

Furthermore, the position of the conformer (30) and the working piston rods pressure-free coupling (33a) can be seen whether the working machine drives the refrigerator or not. Fluid and piston movement directions are indicated by arrows

The following happens during the three work phases

Fig. 9a. Working machine The fluid is heated isochorically from a to b. The displacer (11) moves towards the fixed working piston (26)

Refrigerating machine The fluid is cooled isobarically by moving the displacer from a 'to c'. The working piston (26a) is fixed. The pressure-free coupling (33 a) is disengaged

Fig. 9b Working machine The fluid expands isothermally from b to c Working piston (26) and displacement piston (11) move down together. The pressure-free coupling (30) is engaged. The shut-off element (29) is open

Refrigerating machine The working piston (26a) compresses the fluid. The displacer piston is fixed in the outer dead center. The shut-off element (29a) is open

Fig 9c Working machinery The fluid contracts through regenerative cooling from c to a. Working and displacement pistons (26, 11) move upwards in parallel. The shut-off element (29) is open. The pressure-free coupling (30) is disengaged

Refrigerating machine The working piston (26a) is fixed at the bottom dead center by the shut-off element (29a). The displacer piston pushes the fluid from b 'to a' (isochoric cooling)

The refrigeration machine heat pump therefore absorbs (16a) ambient heat (Kuhler), compresses it isothermally, and releases the heat again via (14a. User) Drive through "reverse" and works at a lower temperature level In addition to the reversible, efficient cycle, it is particularly advantageous that all heat exchange processes can take place from liquid to liquid. In contrast to the usual two-phase mixtures in classic refrigeration machines, this enables much more economical and efficient coolers / heat exchangers. According to the invention, analogous to the by-pass circuit of FIG. 7 (24c, 25c), such an arrangement can also be used in the refrigeration machine and the cooled fluid can thus flow directly through the corresponding heat sink without dead space effects.

Since the drive THK machine and the driven THK refrigeration machine work at different temperature levels, the pressures must be matched to one another. According to the invention, this can be done either by corresponding volume ratios of the working machine cylinder (13) to the refrigerating machine cylinder (13a), or by a corresponding pressure reduction by means of a stepped working piston between the conformer (30) and the refrigerating machine.

Another embodiment of the THK refrigeration machine heat pump according to the invention uses the basic principle of the known Vuilleumier refrigeration machine heat pump, which operates according to the Stirling principle, with adaptation to the special cycle of the THK machine. This variant is shown schematically in FIG.

In a common cylinder (I = "hot" cylinder; II = "cold" cylinder) separated by the well heat-insulated and pressure-resistant wall (34) in two working areas there is a linearly driven displacement piston with connected heater-regenerator-cooler section , The elements assigned to the "hot" cylinder are identified by index a. The elements assigned to the "cold" cylinder are identified by index b. The fluid from cylinder I and cylinder II are connected to one another at the desired time by the valve (35) which can be controlled in time

At the start of the operation, both cylinder halves are filled with the same fluid at the same pressure (advantageously: 1 bar). The displacement drives 12a. 12b move the displacement pistons 11a, 11b with the phase shifted by 90 °.

In the hot cylinder I, the fluid is brought to high pressure by heating by means of 14a. After this pressure has been reached, the valve (35) is opened and the drain fluid from cylinder I compresses the fluid in cylinder II with the development of heat. After the pressure has been equalized, the displacement piston (Ha) moves upwards in the "hot" cylinder, while in the "cold" cylinder the displacement piston moves down.

The respective heat contents in both cylinder I and cylinder II are regenerative the regenerators 15a and 15b are transferred and buffered for the following cycle section. In the third working cycle, (11a) and (11b) move up synchronously. As soon as both have reached their top dead center, the valve (35) closes and the cycle begins again as described.

Basically, in this variant according to the invention, cylinder I acts as a regenerative pressure pulsator, while cylinder II as a refrigeration machine heat pump runs through the cycle of the THK pulsator which is driven through clockwise in cylinder I to the left. Heat is extracted from a desired room by (14b) at low temperature (refrigeration machine) and released again by (16c) at a medium temperature level (heat pump). When operating as a heat pump or as a combined unit (simultaneous generation of cold and heat), it makes sense to connect the heat flows in series using (16c) and (16a).

In principle, the "Vuilleumier THK" refrigerator heat pump described here can also be operated without the valve (35). According to the invention, the valve (35) is replaced in this case by a permanent, small passage opening in the wall (34). In this case the displacers (11a, 11b) are not moved discontinuously by 90 ° out of phase, but continuously out of phase by 90 °. However, this simplification of the cycle according to the invention has a lower power density because of the less usable pressure fluctuation. This can in principle be compensated for by an increased operating frequency However, due to the disproportionately increasing hydraulic pressure losses, the efficiency is poor.

There is a wide range of options for choosing the working fluids. The most important selection criteria are: temperature and cycle stability, strong thermal volume increase, low compressibility, high heat capacity, c _p significantly larger than c _v , high boiling points, low freezing points, environmental compatibility and costs.

The water used by Malone, as described at the outset, has many advantages, but also the fundamental disadvantage that, in order to remain fluid over the entire working cycle, it must be subjected to a pre-pressure of> 100 bar. Although this can basically be achieved with the described THK machines, it requires expansion tanks and air boilers that are filled with this form.

In the current state of the art, preference is therefore given in particular to synthetic oils in which, as described, it is possible to work against atmospheric pressure, and which can be tailored in terms of viscosity, temperature stability, compressibility and other important parameters of the thermodynamics of the THK. Since the THK machines work well in the medium temperature range from approx. 100 ° C to approx. 400 ° C, and the heat input (and cooling) of the fluid is technically particularly easy to implement, the following energy sources for operating the THK are Of particular interest: solar energy including night operation through thermal storage, all biogenic fuels, waste heat in the temperature range mentioned. THK machines and combined THK refrigeration machine heat pumps are particularly suitable for cogeneration in buildings, for decentralized energy supply with sun and / or biomass and for the re-generation of (industrial) waste heat.

The simple and compact design due to the new cycle makes economic investments possible. Due to the high energy density of the fluids, working frequencies of well below 1 Hz can be achieved with reasonable system weights (stationary applications). This not only minimizes the drive power of the displacement pistons, but also increases the service life of the systems.

Claims

claims:

1. Thermo-hydrodynamic booster ("THK") characterized in that a liquid inside a rigid cylinder by means of an auxiliary piston is periodically shifted from hot to cold and vice versa by a heater-generator-cooler or heater-recuperator-cooler arrangement and that the force exerted thereby by the liquid column, which also periodically contracts and expands, is greater than the auxiliary piston driving force.

2. THK according spoke 1, characterized in that the energy liberated during the thermal insulation of the liquid is converted into useful mechanical work via suitable technical devices.

3. THK according to claims 1 and 2, characterized in that the thermally expanding liquid periodically flows through a hydraulic motor and generates rotational energy on its shaft.

4. THK according to claims 1 and 3, characterized in that the hydraulic motor is followed by an expansion tank acted upon with atmospheric pressure or a slight excess pressure.

5, THK according to claims 1 to 4, characterized in that the pressure generated by the expanding liquid column can be controlled in time and in amount by a switchable shut-off element.

6. THK according to claims 1 to 5, characterized in that the desired liquid pressure is either defined by the ratio of the volume flow of the expanding liquid and the swallowing volume of the hydraulic motor, or by a combination of this effect with the controllable shut-off element from spoke 5.

7. THK according to claims 1 to 6, characterized in that the work delivery of the fluid takes place during the expansion, this is relaxed to the ambient pressure or only a slightly higher pressure, and the return of the fluid to the initial stock by contracting via a reversible cooling process he follows.

8. THK according to claims 1 to 7, characterized in that the fluid subject to expansion and contraction is at the same time the hydraulic fluid of the engine.

9. THK according to claims 1 to 6, characterized in that different media are used as working and hydraulic fluid, which are separated from each other by an elastic element.

10. THK according to claims 1 to 9, characterized in that to minimize the resulting hydrodynamic friction when moving the working fluid, the passage cross-sections in the heater, regenerator-recuperator, cooler is adjusted to the temperature-viscosity behavior of the working fluid.

11. THK according to claims 1 to 10, characterized in that the oscillating linear force development of the expanding liquid column directly, without the conversion into rotational energy with the interposition of suitable pressure converters for compressing air, for generating pressure in reverse osmosis systems, for operating refrigeration compressors and the like , energy converters working with linear movements.

12. THK according to claims 1 to 11, characterized in that a machine equipped with a pressure conformer and a linear pressure-less coupling is operated by means of external energy and works as a refrigerator heat pump.

13. THK according spoke 12, characterized in that the driving energy consists of a THK drive machine.

14. THK according to claims 1 to 10, characterized in that the refrigerator heat pump is realized by a 1-cylinder arrangement, in which a THK machine working in the hot part of the cylinder serves as a drain pulsator, while one in the cold part of the cylinder working, the cycle reversing, phase-shifting working second THK machine works as a refrigerator heat pump.

15. THK according to claims 1 to 10, characterized in that several, phase-shifted driven cylinders lead to a smoothing of the power output.

16. THK according to claim 15, characterized in that in multi-cylinder arrangements, the regenerators can be replaced by countercurrent heat exchangers between the cylinders.

17. THK characterized in that a liquid enclosed in a working cylinder is periodically shifted between a hot and cold source by means of a displacement piston by a heat generator and the expansion volume flow which builds up when heated under pressure is converted into mechanical rotational energy by a hydraulic, downstream motor , whereby the liquid is regeneratively recooled in the regenerator after the engine has been submitted and the volume is reduced so that it fits back into the cylinder.

18. THK, characterized in that a liquid enclosed in a working cylinder is penetrated by a regenerator moving back and forth between a hot and cold source and the expansion volume flow that builds up when heated under pressure is converted into mechanical rotational energy by a hydraulic, downstream motor, the liquid is regeneratively cooled in the regenerator after the work has been carried out on the engine and is thus reduced in volume so that it fits back into the working cylinder.

19. THK characterized in that a liquid is periodically heated and then cooled again, so that the expanding pressure-volume flow that occurs during heating does mechanical work in a working machine and the volume contraction that occurs during the subsequent cooling takes the liquid to the starting point of a thermo - leads back to the dynamic cycle.