DE102018001105A1 - Device and method as a thermal gas engine with regenerative CO2 circulation and heat pump process - Google Patents

Abstract

This method, whose function is based on the enthalpy and pressure differences of a high-pressure gas, should be used to increase the efficiency of conventional gas engines. Compared to conventional gas engines, this process generates more electrical energy.
By means of a refrigeration system pressure and temperature differences are generated, which allow to increase the entropy of CO2 so far that a connected gas engine can be driven more economically.
The device is used as a gas engine in biogas plants, or for general power generation.

Description

Device and method as a thermal gas engine with regenerative CO2 circulation and heat pump process in combination with a refrigeration cycle by a high-pressure gas (such as R744 (CO2), R744A etc.) in a closed system initially approximately isochoric and then approximately isobaric (LPG pressure plus. the spring forces and frictional resistance) is heated and liquefied after its expansion. In this case, the countercurrent cycle of a refrigeration process acts on the right-handed cyclic process of a drive by a refrigerant in the pressure-enthalpy diagram left is almost isentropically or polytropically compressed and liquefied, by means of the evaporation of the refrigerant the right-circulating in the enthalpy pressure diagram Liquefying CO2. The CO2 liquid is heated approximately isochorally by means of a heat pump, as well as the hot gas temperature of the compressors and / or with the waste heat of a (bio) gas engine and / or other available heat sources, thereby increasing the pressure of the CO2 liquid. The compressors are thereby driven by smaller gas engines, other internal combustion engines, or electric motors with fuel cell (s).

NAME OF THE INVENTION

Device and method as a thermal gas engine with regenerative CO2 circulation and heat pump process.

TECHNICAL AREA

Power generation, drive technology, biogas plants, heat recovery plants

STATE OF THE ART

It is not known whether a refrigeration system or a heat pump is used to generate high CO2 pressure differences, which in turn can be used to drive a gas engine.

THE ROUNDING PROBLEM

Due to current requirements and targets of national and international authorities, the burning of fossil fuels for energy production due to climate change and pollution should be reduced or eliminated. The use of e.g. Biogas for energy generation contributes to achieving the energy transition. By the method described below, e.g. Biogas is used to liquefy and heat a secondary-connected CO2 cycle and to run a heat pump that uses the thermal energy gained to increase the entropy of CO2 enough to drive a downstream gas engine. The pressure generated in this case can be a multiple of what can be achieved by the explosion of gas, gasoline or diesel. The liquefied CO2 gas is vaporized and liquefied by means of a condenser, so that it is continuously circulated in a closed system. The compressors are operated either by smaller gas engines, or other engines. The energy of the exhaust gases is also used for the approximately isochoric heating of the CO2 liquefied gas, which substantially increases the efficiency of the gas engine. With this method, significantly higher electrical outputs are achieved with the same amount of biogas.

GENERAL

This method utilizes the property of a liquid high pressure gas (such as CO2) to achieve high pressure differences with a small increase in temperature. According to the physical laws of energy conservation, these are predominantly artificially produced temperature and pressure differences. It is used both the energy supply by the evaporation of a refrigerant, as well as the energy dissipation by the liquefaction of a refrigerant in a physically closed system of a cycle process (refrigeration process) as an energy source. That The required energy is extracted from the environment (soil, water, air and other heat sources) with the help of a heat pump, and the energy of the exhaust gases of the drive motors and the compression energy of the compressors used to high CO2-pressures and high enthalpy To get differences.

All valves described below can be carried out directly or pilot-controlled, or via e.g. Camshafts are opened and closed. All pressure control valves can be controlled mechanically, thermo-mechanically, or via pressure or temperature transmitters and electronics. The drives of all automated valves can be either mechanical, electro-mechanical, electrical, electro-magnetic, pneumatic, hydraulic, or equivalent. The listed heat exchangers can be designed as tube bundle, as well as plate, or micro-channel heat exchangers or other heat exchange technologies. The apparatus described below and the method described, which is to be used as an economical drive of gas engines, generates by means of the aforementioned energy sources large enthalpy differences at high pressures acting on the piston surfaces of the gas engine.

list of figures

• 1 :
  • The representation of the pressure-temperature curve of CO2 compared to NH3 is intended to illustrate that only a small increase in temperature of CO2, or similar high-pressure gas leads to high pressures. It requires a low energy input, which leads to the economic drive of gas engines.
• 2 :
  • Representation of the process in the pressure-enthalpy diagram to illustrate the process of two separate cycle processes, the left-handed cycle of a cooling circuit (ABDE) the right-handed cycle (GHKL) cools and may also be heated. In the left-handed cycle, a different refrigerant can be used than in the clockwise cycle. It should be noted that the figure is only for understanding the device and the method. The exact position of the individual lines, or the operating states can vary depending on the actual prevailing pressures, temperatures, enthalpy, etc. and are therefore not binding for the process. Because of the efficiencies, the frictional resistances, the spring forces, the opening differential pressures of the valves used, the pressure losses in the components used, such as heat exchangers, pipelines, etc. change the operating states shown in the diagram, so that the terms used here isobaric, isochoric, isentrop, etc. not exactly apply, but should only serve as a guide. If, for example, the term "at constant enthalpy" is used, this can only refer to an adiabatic state change, whereby the enthalpy in real states does not necessarily have to be constant. but can change eg depending on the entropy. The same applies, among other things, to the pressure, temperature, and density specifications, which are only intended to serve as an understanding and may deviate from the real states.
  • A gas compressor ( 1 ), which may also be operated without oil to prevent the combustion of the lubricant at high compression end temperatures, sucks the superheated gas from the point ( A ) and condenses it to point ( B ). The hot gas with the enthalpy difference distance (BC) is used for the isochoric heating of the CO2 liquid ( 8th ) with enthalpy difference ( HG ) used. Should the enthalpy difference ( BC ) smaller than the enthalpy difference ( HG ), or the compression end temperature ( B ) lower than the required temperature at the point ( H ), the heat energy of the heat pump and / or the exhaust heat energy of the biogas engine of the compressor ( 1 ) used to compensate for this.
  • The refrigerant is removed from the point ( C ) to point ( D ) cooled from the ambient temperature of the device, liquefied and possibly supercooled. Is the heat of compression of the track ( 2 ) from the point ( B ) to approx. point ( C ) not for the approximately isochore heating of the liquid ( 8th ), this amount of heat is also released to the ambient air, ie the refrigerant is from the point ( B ) to point ( D ) cooled by the ambient air of the device, liquefied and possibly supercooled. As with a conventional cooling circuit, the condensation temperature or the pressure of the sections ( 2 ) and ( 3 ) above the ambient temperature to dissipate the heat accordingly. The used refrigerant in the circuit ( FROM - DE ) can from the high-pressure gas of the circuit ( GH - KL ), so that liquefaction in the subcritical range is possible. In the cycle ( FROM - DE ) can also be a high-pressure refrigerant, such as CO2, are used, but that is cooled in the trans-critical range and may not be liquefied. In this case, the point ( D ) are in the transcritical range (not shown). The refrigerant is removed from the point ( D ) to point ( e ), that is expanded at constant enthalpy. This expanded refrigerant takes in a heat exchanger ( 5 ) the energy of the likewise expanded high-pressure refrigerant ( 7 ) to get this from the point ( L ) to point ( G ) to cool and liquefy. That from the point ( F ) to point ( A ) superheated refrigerant is returned from the compressor ( 1 sucked). To the compression end temperature ( B ) above the temperature at the point ( H ) or alternatively at the point ( K ), with which the liquefied gas on the route ( 8th ) isochorous and optionally isobaric ( 9 ), the length of the track ( 6 ) be extended with eg an additional heat exchanger. In the case of greater overheating, point ( A ) and therefore also point ( B ) moved to the right. The amount of heat required for this purpose can be withdrawn from the ambient air, the remaining waste heat of the Biogas engine, or any other available heat sources.
  • The cooling circuit ( FROM - DE ) is therefore primarily used for the liquefaction of a high-pressure gas, such as R744, R744A or similar, and optionally also for the isochoric heating of the liquefied gas ( 8th ), used in the form of heat recovery according to the principle of a heat pump.
  • The liquefied CO2 at the point ( G ) is pumped into a closed, expandable container (loading cylinder), which is completely filled with the liquid. After filling, the inlet is closed so that the liquid does not move backwards from point ( G ) in the direction ( L ) can flow. The liquid container ( 8th ) must match the pressures at the point ( H ) and possibly from point ( H ) to point ( K ) be expandable, which could be realized with the help of eg two telescoping cylinders with attached tension springs. The CO2 liquid in the container ( 8th ) can be heated with internal and / or external heat exchangers in order to initially close the caged liquid ( GH ) and then approximately isobaric ( HK ) to heat.
  • As already mentioned above, for the isochore heating of the liquid ( 8th ) with enthalpy difference ( HG ) the hot refrigerant with enthalpy difference ( BC ), the compression temperature ( B ) should be higher than the temperature at the point ( H ), or at the point ( K ). Should the enthalpy difference ( BC ) smaller than the enthalpy difference ( KG ), or the compression end temperature ( B ) lower than the required temperature at the point ( H ), the heat energy of the heat pump and / or the waste heat of the Biogas engine is used to compensate for this.
  • At the point ( H ) the desired, adjustable pressure is reached. If more energy is supplied, the container expands from point ( H ) to point ( K ) out. Alternatively (must) unintentional, excess pressure in accordance with the valid technical regulations on back pressure-independent safety valves to point ( L ), or be blown off via counter pressure-dependent safety valves in the atmosphere.
  • Is the liquid from point ( H ) to point ( K ) heated approximately along the isobars (plus the pressure increase due to frictional resistance and spring forces), the container expands and the CO2 liquid begins to evaporate, increasing the volume. The length of the route ( 9 ) is variable and must be determined empirically depending on the drive. For heating the liquid from point ( H ) to point ( K ), as under 3 described among other things the heat energy of the heat pump used. The LPG is approximately adiabatic to the surfaces of the pistons, from the point ( K ) to the point ( L ) transfer.
• 3 :
  • Representation of the procedure in the pressure-enthalpy diagram as under 2 However, for the heat pump process, which is responsible for the heating of the CO2 cycle, but not for its liquefaction. The left-handed cycle of a cooling circuit ( A'-B'-D'-E ' ) heated with the track ( B'-C ' ) the right-handed circular process ( GHK ). In the left-handed cycle, a different refrigerant can be used than in the clockwise cycle. As under 2 described, it is noted that the figure is only for understanding the device and the method.
  • A gas compressor ( 1' ), which may also be operated without oil to prevent the combustion of the lubricant at high compression end temperatures, sucks the superheated gas from the point ( A ' ) and condenses it to point ( B ' ). The hot refrigerant with the enthalpy difference path ( B'-C ' ) is used inter alia for the isochoric heating of the CO2 liquid ( 8th ) with enthalpy difference ( HG ) and for the approximately isobaric heating of the point ( H ) to point ( K ) used.
  • The refrigerant is removed from the point ( C ' ) to point ( D ' ) cooled from the ambient temperature of the device, liquefied and possibly supercooled. Is the heat of compression of the track ( 2 ) from the point ( B ' ) to approx. point ( C ' ) not for the heating of the liquid ( 8th & 9 ), this amount of heat is also released to the ambient air, ie the refrigerant is from the point ( B ' ) to point ( D ' ) cooled by the ambient air of the device, liquefied and possibly supercooled. As with a conventional cooling circuit, the condensation temperature or the pressure of the sections ( 2 ' ) and ( 3 ' ) above the ambient temperature to dissipate the heat accordingly. The refrigerant is removed from the point ( D ' ) to point ( e ' ), that is expanded at constant enthalpy. This expanded refrigerant takes in a heat exchanger ( 5 ' ) the energy from the soil, from the ambient air, the water, or another energy source. The heat pump cycle ( FROM' - D'-E ' ) is therefore used primarily for heating the high-pressure gas, such as R744, R744A or similar, by the energy is transferred to the previously liquefied CO2 in a closed, expandable container (load cylinder).
• 4 :
  • Presentation of the CO2 cycle according to ( GH - KL . 2 ). Alternatively, another high-pressure gas can be used. The CO2 is removed from the refrigeration cycle ( 8th ) in the liquefier ( 43 ) liquefied and in the collector ( 45 ) and possibly undercooled. The liquid, supercooled CO2 is removed with the help of the charge pump ( 50 ) one of the two loading cylinders ( 30a or 30b . 6 ).
  • Filling the loading cylinder ( 30a) : The two solenoid valves ( 52a and 56a) are first opened to the loading cylinder ( 30a) with the help of the charge pump ( 50 ) to fill with liquid CO2 and dissipate the existing heat energy. Then the solenoid valve ( 52a) closed. The charge pump ( 50 ) pumps liquid CO2 via the solenoid valve ( 56a) in the loading cylinder ( 30a) , The remaining solenoid valves ( 53a and 54a) remain closed during the charging process. If the loading cylinder is completely filled, the solenoid valve ( 56a) , The CO2 is now as under 8th described, approximately isochoric and then heated approximately isobaric, with the pressure further increases and the loading cylinder expands. At maximum extension of the loading cylinder ( 30a) will the solenoid valve ( 54a) open. The CO2 is thus directed to the piston surfaces of the gas engine, where it performs drive work. After the work has been done, the CO2 flows out of the gas engine via the expansion valve ( 23 ) in the liquefier ( 43 ). Is the loading cylinder ( 30a) almost empty, the solenoid valve closes ( 54a) and the solenoid valve ( 53a) will be opened. The rest, in the loading cylinder ( 30a) located CO2 pressure, is via the expansion valve ( 57 ) in the liquefier ( 43 ) relaxed.
  • Filling the loading cylinder ( 30b) : The two solenoid valves ( 52b and 56b) are first opened to the loading cylinder ( 30b) with the help of the charge pump ( 50 ) to fill with liquid CO2 and dissipate the existing heat energy. Then the solenoid valve ( 52b) closed. The charge pump ( 50 ) pumps liquid CO2 via the solenoid valve ( 56b) in the loading cylinder ( 30b) , The remaining solenoid valves ( 53b and 54b) remain closed during the charging process. If the loading cylinder is completely filled, the solenoid valve ( 56b) , The CO2 is now as under 8th described, approximately isochoric and then heated approximately isobaric, with the pressure further increases and the loading cylinder expands. At maximum extension of the loading cylinder ( 30b) will the solenoid valve ( 54b) open. The CO2 is thus directed to the piston surfaces of the gas engine, where it performs drive work. After the work has been done, the CO2 flows out of the gas engine via the expansion valve ( 23 ) in the liquefier ( 43 ). Is the loading cylinder ( 30b) almost empty, the solenoid valve closes ( 54b) and the solenoid valve ( 53b) will be opened. The rest, in the loading cylinder ( 30b) located CO2 pressure, is via the expansion valve ( 57 ) in the liquefier ( 43 ) relaxed.
• 5 :
  • Illustration of a 4-cylinder gas engine with piston ( 18a to 18d) which are connected via the respective connecting rods to the common crankshaft ( 19 ) are attached. It is also possible to use piston engines with more or less cylinders. The number of cylinders is not relevant or binding for the procedure. The CO2, or another high-pressure gas, is released via the intake valves ( 20a . 20b . 20c and 20d) delayed in the respective cylinder heads ( 22a to 22d) directed. The control of all intake and
  • Exhaust valves can be via a conventional camshaft, or via another mechanical, electro-magnetic, hydraulic, or pneumatic control. The mutually open solenoid valves ( 54a & 54b) control the inflow of CO2 to the intake valves. After the drive work of the respective piston,
  • is the CO2 via the associated exhaust valve ( 21a . 21b . 21c or 21d) from the cylinder head ( 22a to 22d) conveyed and via the expansion valve ( 23 ) into the condenser.
• 6 :
  • As 5 , Presentation of the inlet ( 20a & 20b ) and exhaust valves ( 21a & 21b ), which can be controlled by a camshaft as in a conventional gas engine.
• 7 :
  • Representation of two expandable loading cylinders, each consisting of two halves ( 30a & 30a2 ) and ( 30b & 30b2 ), which can be superimposed or pushed into each other. A seal ( 34 ) prevents the escape of gas into the atmosphere. Alternatively, a bellows technique or the like may be used. The CO2 in the respective loading cylinder is from point ( G . 1 ) to point ( K . 1 ) along the routes ( 8th & 9 ) is heated. At the selectable point ( H . 1 ) the loading cylinder begins to expand until the selectable point (K, 1 ) is reached. If the point (K, 1 ), the solenoid valve ( 54a or. 54b) to direct the CO2 into the gas engine. Tension springs ( 31 ) hold the two cylinder halves ( 30a & 30a2 ) or. ( 30b & 30b2 ) together. When crossing point ( H . 1 ) catch the feathers ( 31 ) in itself to point ( K . 1 ) expand. The loading cylinder ( 30a) is below or at the point ( H . 1 ) and the loading cylinder ( 30b) is at the point ( K . 1 ) with the loaded tension springs ( 31 ) and the extended cylinder half ( 30b2 ). The respective function of the remaining solenoid valves will be described in the following figures. The respective solenoid valves will be described elsewhere.
• 8th :
  • Function of the loading cylinder ( 30a / 30b) as under 6 described. This figure shows the heating methods of the two loading cylinders. The compressor ( 42 ) obtained from a biogas engine ( 43a) is driven, compresses a refrigerant to the condensing pressure. In the heat exchanger ( 33 ) is a part of the heat energy of the refrigerant to the CO2, with the help of the circulating pump ( 36a) with optional overflow valve alternately into the loading cylinder ( 30a) or the loading cylinder ( 30b) passed. Is in the heat exchanger ( 33 ) requires no or less heat energy, the solenoid valve opens ( 39b) the bypass to the liquefier ( 44 . 8th ). The CO2 is released from the pump ( 36a) over the open solenoid valves ( 51a / 55a) or ( 51b / 55b ) in order to calculate the CO2 with the enthalpy difference ( BC . 1 ) of the compressor, from the point ( G . 1 ) to point ( H and or K . 1 ), along the routes ( 8th & 9 ) to heat.
  • The compressor ( 42 ) is powered by a biogas engine ( 43a) driven. The energy of the exhaust gases of the biogas engine ( 43a) is in the heat exchanger ( 43b) delivered to the CO2. As described above, the CO2 from the pump ( 36b) over the open solenoid valves ( 51a / 55a) or ( 51b / 55b ) circulated.
  • The compressor ( 60 ) of another biogas engine ( 61a) is driven, compresses a refrigerant to the condensing pressure. In the heat exchanger ( 66 ) is a part of the heat energy of the refrigerant to the CO2, with the help of the circulating pump ( 35a) with optional overflow valve alternately into the loading cylinder ( 30a) or the loading cylinder ( 30b) passed. Is in the heat exchanger ( 66 ) requires no or less heat energy, the solenoid valve opens ( 67 ) the bypass to the liquefier ( 62 . 9 ). The CO2 is released from the pump ( 35a) over the open solenoid valves ( 51a / 55a) or ( 51b / 55b ) in order to calculate the CO2 with the enthalpy difference ( BC . 1 ) of the compressor, from the point ( G . 1 ) to point ( H and or K . 1 ), along the routes ( 8th & 9 ) to heat.
  • The compressor ( 60 ) is powered by a biogas engine ( 61a) driven. The energy of the exhaust gases of the biogas engine ( 61a) is in the heat exchanger ( 61b) delivered to the CO2. As described above, the CO2 from the pump ( 35b) over the open solenoid valves ( 51a / 55a) or ( 51b / 55b ) circulated.
• 9 :
  • Representation of the cooling circuit, consisting of a compressor ( 42 ) with biogas engine ( 43a) , Heat exchangers ( 33 ), Liquefier ( 44 ), optional heat exchanger as superheater ( 48 ), Evaporator ( 43 ), CO2 collector with supercooling evaporator ( 45 ), Expansion valves ( 46b and 49b) , as well as various solenoid valves ( 46a . 49a . 47a . 47b and 39b) ,
  • The compressor ( 40 ) sucks the vaporized refrigerant from the evaporator ( 43 ) and compresses it to the condensation pressure. To the final compression temperature (point B, 2 ), the superheat exchanger ( 48 ) via the solenoid valves [ 47a (On and 47b (ZU)] are switched on, whereby the already superheated suction gas receives more energy from the ambient air. The polytropic compaction (range 1 . 2 ) is shifted further to the right in the pressure-enthalpy diagram to a larger, usable enthalpy difference (distance 2 . 2 ), which is used for isochoric heating of the CO2 liquid in the heat exchanger ( 33 ) can be used. The connection of the superheater ( 48 ), if a higher compression temperature is needed. The heat of compression is transferred via the heat exchanger ( 33 ) to the liquid CO2 of that loading cylinder ( 30a or. 30b) which is heated at this time, while the other load cylinder ( 30a or. 30b) unloads at the same time, or does work. The heating of the CO2 liquid takes place by opening the associated solenoid valve ( 51a / 55a or. 51b / 55b . 4 ). After release of heat energy (distance 2 . 2 ), the refrigerant enters the condenser ( 44 ), where the remaining amount of heat (distance 3 . 2 ) is discharged to the ambient air and the refrigerant is thereby liquefied and possibly undercooled (point D . 2 ). The liquefied refrigerant is released via the solenoid valve ( 49a) and the expansion valve ( 49b) in the heat exchanger ( 43 ), where it absorbs the amount of heat of the CO2 liquid, which is thereby liquefied. The heat exchanger ( 43 ) is evaporator of the refrigerant and condenser of CO2. In the CO2 collector ( 45 ) is an internal heat exchanger to cool the accumulated CO2. Liquid refrigerant is for this purpose via the solenoid valve ( 46a) and the expansion valve ( 46b) into the heat exchanger in the collector ( 45 ), whereby heat energy is absorbed by the liquid CO2 and this is undercooled. Is in the heat exchanger ( 33 ) no energy is required, the solenoid valve opens ( 39b) the bypass to the liquefier ( 44 ).
• 10 :
  • Representation of the heat pump cycle, excluding the heating of CO2, according to 3 serves. The compressor ( 60 ) sucks the vaporized refrigerant from the evaporator ( 65 ) and compresses it to the condensation pressure. The evaporator ( 65 ), the heat energy from the ground, the air, the water or other heat sources. The heat of compression is transferred via the heat exchanger ( 66 ) to the liquid CO2 of that loading cylinder ( 30a or. 30b) which is heated at this time, while the other load cylinder ( 30a or. 30b) unloads at the same time, or does work. The heating of the CO2 liquid takes place by opening the associated solenoid valve ( 51a / 55a or. 51b / 55b . 4 ). After release of heat energy (distance 21 . 2 ), the refrigerant enters the condenser ( 62 ), where the remaining amount of heat (distance 22 . 3 ) is discharged to the ambient air and the refrigerant is thereby liquefied and possibly undercooled (point D ' . 3 ). The liquefied refrigerant is released via the solenoid valve ( 63 ) and the expansion valve ( 64 ) in the evaporator ( 65 ), where it absorbs the amount of heat from the environment. Is in the heat exchanger ( 66 ) no energy is required, the solenoid valve opens ( 67 ) the bypass to the liquefier ( 62 ).

Claims (10)

Method as a thermal gas engine with regenerative CO2 circulation and heat pump process, characterized in that a pressure-enthalpy diagram shown, right-handed cycle of a high-pressure gas is operated with a left-handed cycle of a cooling circuit by the left-handed cooling circuit liquefies the right-handed high-pressure gas, the Drive a gas engine is used. Method according to Claim 1 , characterized in that a gas compressor is driven by an internal combustion engine and the heat energy of the exhaust gases of the engine is used for the approximately isochore heating of a liquefied gas, which is used to drive a gas engine without combustion processes. Method according to Claim 1 or Claim 2 , characterized in that the adiabatic change in state of a liquefied gas, the pistons of a motor are driven without combustion processes, the expanded liquefied gas after performing work in a closed circuit regenerated liquefied again, heated and brought to high pressure. Method according to one of Claims 1 to 3 , characterized in that a liquefied gas is heated approximately isobarically in its transcritical region and either the heat energy of a heat pump or the compression energy of a gas compressor, or both energies for the approximately isobaric heating of the liquefied gas is used. Method according to one of Claims 1 to 4 , characterized in that a heat pump is used to operate a gas engine with a regenerative CO2 circulation. Method according to one of Claims 1 to 5 , characterized in that a regenerative, shown in the pressure-enthalpy diagram, right-handed Carnot cycle of a high-pressure gas without the combustion of a left-handed cycle of a refrigerant is cooled. Method according to one of Claims 1 to 6 , characterized in that an engine is operated by a high-pressure gas without combustion processes by acting at the inlet of the engine, the pressure of the high-pressure gas in the trans-critical region and at the outlet of the engine, the pressure of the high-pressure gas in the subcritical region. Method according to one of Claims 1 to 7 , characterized in that a gas is used to drive a motor, which is not consumed, but is circulated continuously in a closed system. Method according to one of Claims 1 to 8th , characterized in that a heat pump is used to increase the heat energy obtained, the pressure of a liquefied gas, which is transmitted to the pistons of a motor to drive them. Method according to one of Claims 1 to 9 , characterized in that a liquefied refrigerant is brought with the same further pressure and temperature increase in the trans-critical region of the same, in order to drive a motor by the expansion of the refrigerant without further combustion processes.

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