Thermal machine and relative method for realizing thermodynamic cycles

Abstract

The present invention is relative to a thermal machine (100), operating with a thermal fluid for realizing a thermodynamic cycle, comprising a power unit (1) and a motor circuit (10). The power unit comprises a first operating chamber (3A) and a second operating chamber (3B), housing power transformation organs connected with each other by means of a drive shaft (8). The thermal machine comprises also a lubrication branch (50), operatively active on a casing (2) of the power unit and configured for being affected by a first flow of the thermodynamic fluid for lubricating at least the drive shaft.

Description

[0001] DESCRIPTION

[0002] “THERMAL MACHINE AND RELATIVE METHOD FOR REALIZING THERMODYNAMIC CYCLES”

[0003] FIELD OF THE FINDING

[0004] The present invention has as its object a thermal machine, comprising a power unit provided with motion transmission system and a motor circuit configured for putting in place a thermodynamic cycle in order to achieve a higher unit power, a significant increase in overall efficiency and an efficient lubrication of the movable parts of the power unit. In particular, the present invention has as its object a thermal machine that puts in place a thermodynamic cycle that comprises functions of lubrication of the movable parts of the power unit.

[0005] The present invention refers also to a method for the realization of thermodynamic cycles.

[0006] The thermal machine according to the present invention is usable, generally, for the production of mechanical power. The present invention finds particular place in the production of electrical power in generation plants or in the combined production of electrical and thermal power by means of co-generation and micro-cogeneration plants. Also, the present invention can find application in the field of automotive and in the motor industry in general.

[0007] STATE OF THE ART

[0008] Some historical considerations relative to thermodynamic cycles, as well as some known solutions, are described in the patent applications published with numbers WO2015 / 114602A1, W02019 / 008457A1 and WO2021 / 044338A1 on behalf of the same Applicant.

[0009] Overall, thermal machines operating with diversified thermodynamic cycles have been developed and others are still in the experimental step.

[0010] However, the Applicant has found that the solutions already industrialized have many limitations. This applies, in particular, to engines used to drive small-to-medium power stand-alone electric generators (for example under 50 KWh).

[0011] In today's practice, for the actuation of electric generators, the following power units are typically used:

[0012] - reciprocating endothermic engines, which result mechanically complicated, noisy, particularly polluting and require a lot of maintenance;

[0013] - Stirling engines, which, while being less polluting, result very heavy, bulky and must typically run at low speed to have good overall efficiency;

[0014] - gas turbines, operating with Joule cycle, which, besides being particularly polluting, in small sizes are not economically competitive;

[0015] - expanders, operating with Rankine or Rankine-Hirn cycle, which, because of the need to use a vapour generator of a certain size, are particularly competitive only in stationary cogeneration applications and require further technological innovations in order to be profitably employed also in small-scale mobile applications.

[0016] Known technical solutions can comprise thermal machines that implement thermodynamic cycles wherein a thermal fluid is cyclically subjected to compression, heating, expansion and cooling operations. In some cases, compression and expansion operations can take place in a power unit provided with two respective operating chambers, one dedicated to the compression of the thermal fluid (i.e., the compressor) and one in charge of the expansion of the thermal fluid (i.e., the expander). Such operating chambers are generally connected with each other by means of a transmission apparatus, comprising a drive shaft that enables the transfer of motion between the moving parts of the power unit. This drive shaft is movably housed in a special casing, defined in the power unit and generally conformed as a bushing. Within the relative casing, the drive shaft is free to rotate and / or translate to transmit the motion between the two operating chambers.

[0017] In order to maximize the efficiency of the above-mentioned thermodynamic cycles, a crucial role is assumed by the drive shaft lubrication. Firstly, the lubrication of the drive shaft allows to limit the friction and the wear between the contact surfaces of the shaft itself and its casing. In addition, the lubrication of the drive shaft can also perform cooling and anticorrosive functions of one or more parts of the power unit.

[0018] The parts to be lubricated are represented by those parts of the casing that may come into contact with the drive shaft, such as bearings, elastic joints, supports, thrust bearings and any transmission gears.

[0019] The lubrication means to reduce the friction between the moving parts of the drive apparatus is generally represented by a fluid, configured for adhering to the surfaces of the drive shaft in order to decrease friction with the other elements of the casing that surrounds it.

[0020] Among the lubrication solutions, the one most widely adopted provides for the use of an oil as lubrication means. The oil used has particular properties that allow the sliding between the surfaces of the drive shaft and the casing that surrounds it.

[0021] Other solutions provide for the use of alternative lubrication fluids, both in the liquid and in gaseous state. In fact, there are known solutions that provide for the use of pressurized gas (e.g., pressurized air) or liquids different from the canonical lubrication oils (e.g., water).

[0022] Regardless of the lubricating fluid used, the known thermal machines typically have a dedicated lubricating fluid circulation system. This system is completely separated from the circuit that realizes the thermodynamic cycle and is active on the casing of the drive shaft to determine the circulation of the lubricating fluid. The lubricating fluid circulation system can be provided with a pump, a reservoir and one or more filter elements to ensure an optimal lubrication of the drive shaft while performing the thermodynamic cycle.

[0023] In light of the above, the Applicant noted that the traditional thermal machines have a high complexity due to the need for lubricating the drive shaft by means of a dedicated additional circuit for the circulation of the lubricating fluid.

[0024] PURPOSE OF THE INVENTION

[0025] The general purpose of the present invention, in its various aspects and / or embodiments, is to make available a thermal machine configured for realizing thermodynamic cycles that can be able to overcome one or more of the previously mentioned drawbacks.

[0026] In particular, a purpose of the invention is to propose a thermal machine able to operate an innovative combined thermodynamic cycle that also integrates lubrication functions. Another purpose of the present invention is to describe a thermal machine that allows to increase the overall efficiency of the thermodynamic cycle, while ensuring, at the same time, a greater simplicity of construction with respect to the traditional thermal machines.

[0027] It is also a purpose of the present invention to realize a thermal machine that has a high operating reliability due to the possibility of keeping the drive shaft lubricated during the carrying out of the thermodynamic cycle.

[0028] A further purpose of the present invention is to make available a thermal machine characterized by a simple and rational structure.

[0029] Another purpose at the basis of the present invention is to make available a thermal machine wherein the thermal fluid is not uniquely used for the carrying out of the thermodynamic cycle.

[0030] Yet another purpose of the present invention is to make available a thermal machine wherein the operating chambers are interconnected with each other by means of a perfectly lubricated drive shaft.

[0031] A further purpose of the present invention is to make available a thermal machine characterized by a high thermodynamic efficiency and an excellent power-to-weight ratio.

[0032] A further purpose of the present invention is to be able to realize a thermal machine characterized by a reduced cost of production.

[0033] Yet another purpose of the present invention is to propose a method for realizing a thermodynamic cycle by means of the above-mentioned machine.

[0034] A further purpose of the present invention is to create alternative solutions, with respect to the known art, in the realization of thermal machines, and / or to open to new design fields.

[0035] These purposes, and any others, which will better result during the following description, are substantially achieved by a thermal machine and a method for realizing a thermodynamic cycle according to one or more of the following claims, each of which taken alone (without its dependencies) or in any combination with the other claims, as well as according to the following aspects and / or embodiments, variously combined, also with the above-mentioned claims.

[0036] SUMMARY

[0037] In a first aspect, the invention refers to a thermal machine configured for realizing a thermodynamic cycle. According to said aspect, the thermal machine operates with a thermal fluid for the realization of said thermodynamic cycle.

[0038] In accordance with an aspect, the thermal machine comprises a power unit.

[0039] In an aspect, the power unit comprises a casing delimiting into its interior at least an operating chamber.

[0040] In accordance with the preceding aspect, said casing delimits into its interior at least: a first operating chamber having a first inlet, in fluid communication with a first inlet duct for receiving therefrom a flow, to compress, of said thermal fluid in suction, and a first outlet, in fluid communication with a first outlet duct for sending thereto a flow of said thermal fluid in compression; a second operating chamber, different from said first operating chamber, having a second inlet, in fluid communication with a second inlet duct for receiving therefrom a flow of said thermal fluid in load to be expanded, and a second outlet, in fluid communication with a second outlet duct for sending thereto a flow of said thermal fluid to be discharged.

[0041] In an aspect, said power unit comprises power transformation organs of said thermal fluid, movably housed within said first operating chamber and said second operating chamber. In particular, said power transformation organs are configured for transforming the power, in particular the thermal power, of said thermal fluid in mechanical power, according to an operating cycle.

[0042] In an aspect, said power unit comprises a drive shaft at least partially housed in said casing. In accordance with said aspect, said drive shaft is operatively connected to said power transformation organs and is configured for connecting said first operating chamber and said second operating chamber with each other. Preferably, said drive shaft is configured for transferring said mechanical power between said first operating chamber and said second operating chamber.

[0043] In accordance with an aspect, the thermal machine comprises a motor circuit.

[0044] According to an aspect, the motor circuit develops between said first inlet, said second inlet, said first outlet and said second outlet and comprises said first inlet duct, said first outlet duct, said second inlet duct and said second outlet duct.

[0045] In an aspect, the motor circuit realizes a continuous cycle of flow of said thermal fluid through said power unit, wherein:

[0046] - said second outlet duct starts from said second outlet of the casing of the power unit and ends by connecting itself continuously with (that is, it confluences at the beginning of) said first inlet duct, the latter ending in said first inlet of the casing of the power unit;

[0047] - said first outlet duct starts from said first outlet of the casing of the power unit and ends by connecting itself continuously with (that is, it confluences at the beginning of) said second inlet duct, the latter ending in said second inlet of the casing of the power unit.

[0048] In accordance with the preceding aspect, the second outlet duct and the first inlet duct realize a first branch of the motor circuit. Analogously, the first outlet duct and the second inlet duct realize a second branch of the motor circuit. Preferably, said first branch of the motor circuit is a closed branch and said second branch of the motor circuit is a closed branch.

[0049] In an aspect, said thermal fluid flows in said motor circuit from said first outlet to said second inlet and from said second outlet to said first inlet. It is to be noted that in this document, the terms "upstream” and "downstream” are intended to refer to a direction of fluid flow within the motor circuit, i.e., to a direction ranging from said first outlet to said second inlet and from said second outlet to said first inlet.

[0050] In an aspect, said thermal machine comprises a lubrication branch. Said lubrication branch is interposed between said first branch and said second branch. In accordance with said aspect, said lubrication branch is configured for being affected by a first flow deriving from said thermal fluid circulating in said motor circuit.

[0051] In accordance with said aspect, the first flow circulating in said lubrication branch coincides at least in part with the thermal fluid circulating in said motor circuit. In accordance with said aspect, the first flow comes from the thermal fluid circulating in the motor circuit; therefore, the first flow contains at least a part of the components of the thermal fluid circulating in the motor circuit.

[0052] In an aspect, said lubrication branch is active on said casing for lubricating at least said drive shaft by means of at least part of said first flow. In the present document, with the term "lubrication” or "lubricating” is intended an activity designed to promote the relative movement (for example, sliding) of two or more elements in contact, typically by means of interposition of appropriate friction-reducing substances. In this sense, the lubrication branch is suitable for promoting the movement, in particular the rotation, of said drive shaft inside said casing of the power unit by means of the use of said first flow.

[0053] According to another aspect, the thermal machine comprises a heater operatively active, along said second branch of the motor circuit, between said first outlet duct and said second inlet duct. In said aspect, said heater is configured for heating the thermal fluid circulating in the second branch.

[0054] According to an aspect, said thermal machine comprises a condenser, operatively interposed, along said first branch of the motor circuit, between said second outlet duct and said first inlet duct. Said condenser is configured for cooling the thermal fluid circulating in the first branch.

[0055] In accordance with an aspect, said thermal machine comprises a condensate separator, placed downstream of the condenser along said first inlet duct. In accordance with said aspect, said condensate separator is configured for separating a liquid component and a gaseous component present in said thermal fluid before it reaches said first inlet. Specifically, said condensate separator is configured for separating, for example by condensation, the liquid component from the gaseous component of the fluid cooled by said condenser.

[0056] For convenience, in an absolutely exemplary and non-limiting way, in the present description the liquid component separated by the condenser will be indicated as "water”, while the gaseous component will be indicated as "air.” In the following, some components of the fluid that can circulate in said motor circuit will be indicated also therein in an absolutely exemplary and non-limiting way.

[0057] In an aspect, said lubrication branch is operatively connected to said condensate separator. In accordance with said aspect, said first flow circulating in said lubrication branch comprises at least part of the liquid component present in said condensate separator. It is to be noted that in the present document, the expression "operatively connected” contemplates both a direct connection, with actual contact between the elements, and an indirect connection, by means of the interposition of other elements adapted to enable communication between the connected elements.

[0058] In an aspect, said lubrication branch comprises at least:

[0059] - a supply duct configured for receiving said first flow;

[0060] - a return duct configured for introducing said first flow in said second branch;

[0061] - a lubrication segment interposed between, and in fluid communication with, said supply duct and said return duct.

[0062] In accordance with the preceding aspect, said lubrication segment defines a compartment configured for housing, at least partially, said drive shaft. In accordance with said aspect, said compartment is configured for surrounding said drive shaft. In particular, said lubrication compartment is obtained within said casing and is configured for housing, at least partially and in a movable way, said drive shaft, defining around it a gap adapted to be affected by at least part of said first flow.

[0063] In an aspect, said drive shaft is free to rotate around a relative axis of rotation. Said axis of rotation coincides preferably with an axis of longitudinal development of said drive shaft.

[0064] In an aspect, said lubrication segment is configured for receiving at least a part of said first flow from said supply duct.

[0065] In an aspect, said lubrication segment is configured for sending said at least a part of said first flow to said return duct.

[0066] In an aspect, the thermal machine comprises a vaporization pipeline that develops from said condensate separator to said second branch in a point of said first outlet duct, i.e. upstream of said heater.

[0067] In an aspect, said vaporization pipeline is configured for being affected by at least part of the liquid component present in said condensate separator.

[0068] In an aspect, said thermal machine comprises a first pump, configured for withdrawing at least a part of the liquid component from said condensate separator and for sending in said vaporization pipeline confluent in said second branch.

[0069] In an aspect, said thermal machine comprises a vaporizer, positioned in the thermal machine in such a way as to intercept, from a high temperature side thereof (or first side), said second outlet duct downstream of the power unit and upstream of the condenser and, from a low temperature side thereof (or second side), said vaporization pipeline.

[0070] In an aspect, the vaporizer is configured for heating and vaporizing the liquid component circulating in said vaporization pipeline before it flows in said second branch.

[0071] In an aspect, the thermal machine comprises a first injector, placed at the end of said vaporization pipeline and configured for injecting in the second branch, upstream of the heater, said liquid component vaporized by said vaporizer. Specifically, the introduction in said second branch of the heated and vaporized liquid component allows to increase the unitary power of the power unit.

[0072] In an aspect, the vaporizer is operatively interposed, on the low temperature side thereof, between said first pump and said first injector, and is operatively interposed, on the high temperature side thereof, between said second outlet of the second operating chamber, which expels exhausted thermal fluid, and the condenser. In said arrangement, the vaporizer acquires at least part of the residual power (i.e., heat) from the exhausted thermal fluid in outlet from the second operating chamber and uses it for pre-heating the thermal fluid in transit in said vaporization pipeline toward the heater.

[0073] In an aspect, the vaporizer is a heat exchanger.

[0074] According to a further aspect, the vaporizer is a heat exchanger provided with two sides which intercept - respectively - the second outlet duct and the vaporization pipeline so as to transfer heat from the thermal fluid circulating in the second outlet duct to the fluid circulating in the vaporization pipeline.

[0075] In accordance with an aspect, the vaporizer determines a cooling of the thermal fluid circulating in the second outlet duct and a corresponding heating of the fluid circulating in the vaporization pipeline. In an aspect, said return duct ends in a point of said first outlet duct upstream of said heater.

[0076] In an aspect in accordance to the preceding aspect, said return duct ends at said first injector.

[0077] In an aspect, said lubrication branch starts at said condensate separator. In accordance with said aspect, said supply duct is in direct fluid communication with said condensate separator. In accordance with said aspect, both said supply duct and said vaporization pipeline are connected to said condensate separator for being affected by at least a part of the liquid component separated by the same condensate separator.

[0078] In an aspect, said lubrication branch comprises a second pump configured for withdrawing at least a part of the liquid component from said condensate separator. Specifically, said at least a part of the liquid component withdrawn by the second pump coincides with said first flow circulating in said lubrication branch.

[0079] In an aspect, said second pump is operatively active on said supply duct for generating said first flow along said lubrication branch.

[0080] In an aspect, said vaporization pipeline comprises a first diverter valve. In accordance with said aspect, said supply duct starts from said first diverter valve.

[0081] In an aspect, said first diverter valve is configured for distributing, between said vaporization pipeline and said supply duct, the liquid component withdrawn from said condensate separator by means of said first pump.

[0082] In an aspect, said first diverter valve is configured for sending said first flow to said lubrication branch, in particular to said supply duct, and for sending a second flow to a remaining portion of said vaporization pipeline downstream of said first diverter valve. In accordance with said aspect, said first flow and said second flow constitute together the liquid component withdrawn from said condensate separator by means of said first pump. In other words, the first pump withdraws at least part of the liquid component present in the condensate separator and sends it to said first diverter valve, which is configured for distributing it between said lubrication branch and said vaporization pipeline (generating the second flow). The part of liquid component that is sent to the lubrication branch coincides with the first flow, which affects the lubrication compartment wherein is at least partially housed the drive shaft; the remaining part of the liquid component is sent to the vaporization pipeline for then reaching the vaporizer.

[0083] In an aspect, said lubrication branch comprises a cooling segment. Said cooling segment is active on said casing. In accordance with said aspect, said cooling segment is configured for being affected by at least a part of said first flow for a thermal exchange with said casing.

[0084] In an aspect, said cooling segment is configured for withdrawing heat from said casing. In other words, said cooling segment is active on said casing for cooling it.

[0085] In an aspect, said cooling segment is interposed between said supply duct and said return duct.

[0086] In an aspect, said cooling segment is in fluid communication with said supply duct and with said return duct. Specifically, said cooling segment is configured for receiving from said supply duct at least part of the first fluid flow and for reintroducing said at least a part of said first flow in said return duct.

[0087] In an aspect, said lubrication branch comprises a second diverter valve interposed between said supply duct, said lubrication segment and said cooling segment. In an aspect, said supply duct ends in said second diverter valve. According to said aspect, said lubrication segment and said cooling segment start from said second diverter valve.

[0088] In an aspect, said second diverter valve is configured for distributing said first flow, circulating in said supply duct, between said lubrication segment and said cooling segment. In other words, the second diverter valve receives the first flow from the supply duct and distributes it between said lubrication segment and said cooling segment: a part of said first flow is sent to the lubrication segment for affecting said lubrication compartment so as to lubricate said drive shaft, whereas the remaining part is sent to the cooling segment for a heat exchange with the casing of the power unit.

[0089] In an aspect, said lubrication branch comprises a second injector interposed between said return duct, said lubrication segment and said cooling segment.

[0090] In an aspect, said lubrication segment and said cooling segment end in said second injector. According to said aspect, said return duct starts from said second injector.

[0091] In an aspect, said second injector is configured for receiving fluid flows from said lubrication segment and from said cooling segment and for sending said fluid flows to said return duct. In accordance with said aspect, a sum of said fluid flows coincides substantially with said first fluid flow circulating in said lubrication branch. In other words, the flows sent on said lubrication segment and said cooling segment from said second diverter valve are then collected from said second injector and sent to said return duct.

[0092] In accordance with a further aspect, the heater comprises a burner provided with a containment body defining a combustion chamber. According to this aspect, said burner is suitable for being supplied with a plurality of typologies of fuel and is configured for supplying to the heater the thermal power necessary for its functioning. In accordance with an aspect, the heater comprises an injection valve configured for managing in a controlled manner the introduction of fuel for supplying said burner.

[0093] According to a further aspect, said containment body is provided with an inlet of combustion air, typically withdrawn from the environment.

[0094] In accordance with another aspect, said containment body houses said condenser, operatively active along said first branch of the motor circuit, so that the heat withdrawn from said first branch through the condenser is transferred to the combustion air before it reaches the burner, promoting the process of combustion and the heating of the thermal fluid in the second branch.

[0095] In accordance with an aspect, said containment body defines a direction of the flow of the combustion air in the burner that goes from said condenser to said heater.

[0096] According to a further aspect, the thermal machine comprises, housed at least partially in said containment body, one or more of the following elements:

[0097] - a superheater positioned downstream of said burner with respect to the direction of the flow of the combustion air to subtract power from the hot combustion fumes of the burner, and configured for intercepting said vaporization pipeline in a position downstream of said low temperature side of the vaporizer and upstream of said first injector; - a closed cooling circuit, different from said motor circuit and affected by a respective cooling fluid; said cooling circuit comprising:

[0098] - a first heat recovery device, positioned in the containment body in a position downstream of the condenser and upstream of the burner, with respect to the direction of the flow of the combustion air;

[0099] - a cooling unit (gap) operatively associated to the casing of the power unit;

[0100] - a second heat recovery device, positioned in the containment body of the heater in a position downstream of the burner along said direction of the flow of the combustion air;

[0101] - a plurality of cooling ducts connecting in series, to form a circular path, said first heat recovery device, said cooling unit and said second heat recovery device;

[0102] - a cooling pump, placed in said cooling circuit and operatively active on said plurality of cooling ducts to determine a circulation of said cooling fluid in the cooling circuit;

[0103] - an auxiliary hydraulic circuit comprising:

[0104] - an auxiliary recovery device, positioned in the containment body in a position downstream of the burner along said direction of the flow of the combustion air;

[0105] - a plurality of auxiliary pipelines configured for passing through said auxiliary recovery device and for being connected with one or more auxiliary uses, preferably environmental heating utilities and / or sanitary hot water production units;

[0106] - an auxiliary pump, placed in said auxiliary hydraulic circuit and operatively active on said plurality of auxiliary pipelines for determining a fluid circulation in said auxiliary circuit.

[0107] In accordance with a preferential aspect, the fluid circulating in said cooling circuit is at least partially composed by water.

[0108] In accordance with another aspect, said cooling ducts are arranged in the thermal machine in such a way to:

[0109] - interact with said cooling unit, wherein the low temperature cooling fluid withdraws heat from the casing of the power unit, cooling it, and consequently is brought to high temperature, and

[0110] - interact with said first heat recovery device, wherein the high temperature cooling fluid transfers heat to the flow of combustion air, heating it, and consequently returns to low temperature.

[0111] According to an aspect, the thermodynamic cycle of the fluid in the cooling circuit provides that:

[0112] - in said cooling unit the low temperature cooling fluid withdraws heat from the casing of the power unit, cooling it, and consequently is brought to high temperature;

[0113] - in said second heat recovery device the high temperature cooling fluid acquires heat from the hot combustion fumes, cooling them, and consequently undergoes an increase in temperature;

[0114] - in said first heat recovery device the high temperature cooling fluid transfers heat to the flow of combustion air, heating it, and consequently returns to low temperature.

[0115] In accordance with the preceding aspect:

[0116] - said first recovery device is configured for cooling said cooling fluid transferring heat / power to said combustion - said cooling unit is configured for cooling the power unit by means of heat / power transfer from the power unit to the cooling fluid, which undergoes an increase in temperature;

[0117] - said second heat recovery device is configured for heating said cooling fluid acquiring heat / power from hot combustion fumes.

[0118] According to a further aspect, said auxiliary recovery device of the auxiliary hydraulic circuit is configured for recovering power from the combustion fumes and for transmitting it to the fluid circulating in said auxiliary circuit, said power then being available for said auxiliary uses.

[0119] In accordance with another aspect, the thermal machine comprises a fan placed at said combustion air inlet of said containment body of the heater and configured for withdrawing combustion air from the environment and sending it forcibly to said burner for supplying the combustion process.

[0120] According to another non-limiting aspect, the thermal machine comprises a compensation lung positioned downstream of said first outlet of the power unit along said first outlet duct and configured for:

[0121] - accumulating the compressed thermal fluid and making it available for its subsequent use;

[0122] - balancing and optimizing the fluid flow in said motor circuit.

[0123] In an aspect the thermal machine comprises one or more non-return valves placed along the pipelines of the motor circuit of the thermal machine and configured for promoting the circulation of the thermal fluid in an unidirectional way and preventing the outflow of the thermal fluid in opposite direction.

[0124] In an aspect, said power unit comprises an outlet shaft operatively connected to said power transformation organs and configured for receiving said mechanical power and providing in outlet a rotating motion, preferably at constant angular speed.

[0125] In an aspect, said thermal machine comprises a power generator, for example an alternator, connected with said outlet shaft in such a way to receive said rotating motion, preferably at constant angular speed, and generate electric current suitable for supplying an external utility. Specifically, the outlet shaft is cinematically connected to the power transformation organs so as to provide to said power generator the rotating motion, preferably at constant angular speed, generated by the power transformation organs housed inside the power unit.

[0126] In accordance with an aspect, said power transformation organs are configured for transforming the power of said thermal fluid in mechanical power according to an operating cycle that provides a sequence of steps of:

[0127] - suction of thermal fluid in said first operating chamber;

[0128] - compression of the thermal fluid in said first operating chamber and emission of the thermal fluid;

[0129] - loading of thermal fluid in said second operating chamber and expansion of the thermal fluid in said second operating chamber;

[0130] - unloading of thermal fluid from said second operating chamber.

[0131] According to an aspect, said power transformation organs comprise one or more, preferably a plurality of, blades or pistons or equivalent organs.

[0132] In an aspect, said power unit is a thermal engine comprising a compressor, carrying out said steps of suction and compression, and an expander, carrying out said steps of loading, expansion and unloading. In an aspect, said compressor is a multi-stage rotary compressor and said expander is a turbine expander.

[0133] In an aspect, in said first operating chamber, provided with said first inlet and with said first outlet, occur the suction of the thermal fluid and the compression of the thermal fluid.

[0134] In an aspect, in the second operating chamber, provided with said second inlet and with said second outlet, occur the loading of the compressed thermal fluid, the expansion of the thermal fluid and the unloading of the thermal fluid.

[0135] In an aspect alternative to the preceding one, said power unit is a continuous flow power unit, wherein:

[0136] - said first operating chamber is structured for realizing a compressor, configured for operating a suction of fluid and a compression of fluid;

[0137] - said second operating chamber is structured for realizing a turbine, configured for operating a loading of fluid, an expansion of fluid and an unloading of fluid.

[0138] In an aspect, said power unit is an intermittent flow power unit, wherein:

[0139] - said first operating chamber is a variable volume operating chamber, configured for operating a suction of fluid and a compression of fluid;

[0140] - said second operating chamber is a variable volume operating chamber, configured for operating a loading of fluid, an expansion of fluid and an unloading of fluid.

[0141] In an aspect, said thermal fluid circulating in said motor circuit is a mixture comprising a gas and water vapour or water, wherein said gas is preferably air and / or helium and / or other gaseous fluid compatible with the water vapour or the water.

[0142] In an aspect, the thermodynamic cycle realized by the thermal machine is a combined thermodynamic cycle.

[0143] In an independent aspect thereof, the present invention refers to a method for realizing a thermodynamic cycle, the method operating with a thermal fluid and comprising the steps of:

[0144] - arranging a thermal machine, preferably according to one or more of the above-described aspects;

[0145] - carrying out the following steps:

[0146] - starting said power unit, putting in motion said power transformation organs of said thermal fluid;

[0147] - activating an operating cycle comprising the steps of:

[0148] - sucking said thermal fluid in said first operating chamber through said first inlet;

[0149] - compressing said thermal fluid in said first operating chamber and emitting said thermal fluid from said first outlet;

[0150] - heating the thermal fluid circulating in said second branch of the motor circuit through said heater;

[0151] - loading said thermal fluid in said second operating chamber through said second inlet and expanding said thermal fluid in said second operating chamber;

[0152] - unloading said thermal fluid from said second operating chamber through said second outlet.

[0153] In an aspect, said steps of the operating cycle of sucking, compressing, loading, expanding and unloading the thermal fluid determine a transformation of the power of said thermal fluid in mechanical power.

[0154] According to a further aspect, the operating cycle comprises also the following steps of: - sending to said lubrication branch a first fluid flow deriving from said thermal fluid;

[0155] - lubricating said drive shaft by means of at least part of said first flow;

[0156] - feeding said first flow in said second branch at least before the step of loading said thermal fluid in said second operating chamber.

[0157] In accordance with an aspect, the method comprises the step of transferring said mechanical power generated from said transforming organs to said outlet shaft, that supplies in outlet a rotating motion, preferably at constant angular speed.

[0158] In an aspect, the step of starting the power unit 1 is carried out in a way substantially contextual to the following steps:

[0159] - activating said heater for heating the thermal fluid in said motor circuit;

[0160] - activating said condenser for cooling the thermal fluid in said motor circuit;

[0161] - activating said condensate separator for separating a liquid component and a gaseous component of said thermal fluid.

[0162] In an aspect, said first fluid flow comprises at least a part of the liquid component separated by said condensate separator.

[0163] In a further aspect, the method comprises the following steps:

[0164] - the thermal fluid in outlet from said second outlet of the power unit transits in the second outlet duct of the first branch of the motor circuit and passes through the high temperature side of the vaporizer;

[0165] - the thermal fluid continues in the first branch and reaches the condenser wherein is cooled;

[0166] - the thermal fluid continues in the first branch and reaches the condensate separator wherein the liquid component present in the thermal fluid is condensed and separated by the gaseous component, before the thermal fluid reaches said first inlet of the power unit;

[0167] In a further aspect, the method comprises the following steps:

[0168] - at least part of the liquid component of the thermal fluid separated by the condensate separator is sent in said vaporization pipeline, whereas the remaining part is sent in said supply duct of the lubrication branch;

[0169] - the liquid component circulating in the vaporization pipeline passes through the low temperature side of the vaporizer, wherein is heated and vaporized before it flows in said second branch;

[0170] - the vaporized liquid component is introduced in the second branch, upstream of the heater, through the first injector, said vaporized liquid component being able to increase the unitary power of the power unit.

[0171] According to another aspect, said method comprises a step of cooling said casing of the power unit by means of said cooling segment.

[0172] In an aspect, said method comprises a step of distributing the first flow sent in said supply duct between said lubrication segment and said cooling segment. Preferably, said step of distributing is carried out from said second diverter valve.

[0173] In an aspect, said method comprises a step of conveying in said return duct the flows distributed on said lubrication segment and said cooling segment. Preferably, said step of conveying is carried out from said second injector. In a further aspect, the method comprises the following steps:

[0174] - arranging a cooling circuit, comprising the first recovery device, the cooling unit, the plurality of cooling ducts and the cooling pump;

[0175] - carrying out the following steps:

[0176] - the low temperature cooling fluid interacts with the cooling unit, wherein withdraws heat from the casing of the power unit, cooling it, and consequently is brought to high temperature;

[0177] - the high temperature cooling fluid interacts with the first heat recovery device, wherein transfers heat to the flow of the combustion air, heating it, and consequently cools and returns to low temperature;

[0178] - activating the cooling pump for determining the circulation of cooling fluid in the cooling circuit.

[0179] In yet another aspect, the method comprises the following steps:

[0180] - arranging the second heat recovery device in the cooling circuit;

[0181] - carrying out the steps of:

[0182] - in the cooling unit the low temperature cooling fluid withdraws heat from the casing of the power unit, cooling it, and consequently is brought to high temperature;

[0183] - in the second heat recovery device the high temperature cooling fluid acquires heat from the hot combustion fumes, cooling them, and consequently undergoes a temperature increase;

[0184] - in the first heat recovery device the high temperature cooling fluid transfers heat to the flow of the combustion air, heating it, and consequently cools and returns to low temperature.

[0185] In accordance with an aspect, the method comprises the following steps:

[0186] - arranging said auxiliary hydraulic circuit, comprising the auxiliary recovery device, the plurality of auxiliary pipelines and the auxiliary pump;

[0187] - carrying out the steps of:

[0188] - recovering from combustion fumes, through said auxiliary recovery device, a quantity of power;

[0189] - transmitting said power to the fluid circulating in said auxiliary circuit;

[0190] - making available said power for auxiliary uses.

[0191] In an aspect, said thermal fluid circulating in said motor circuit is a mixture comprising a gas and water vapour or water, wherein said gas is preferably air and / or helium and / or other gaseous fluid compatible with the water vapour or the water.

[0192] In an aspect, the thermodynamic cycle realized by the method is a combined thermodynamic cycle.

[0193] Each of the above-mentioned aspects of the invention may be taken alone or in combination with any of the claims or of other aspects described.

[0194] Additional characteristics and advantages will become more apparent from the detailed description of some embodiments, exemplary but non-exclusive, of a thermal machine and of a method for realizing a thermodynamic cycle in accordance with the present invention.

[0195] BRIEF DESCRIPTION OF FIGURES Some embodiments and aspects of the invention will be described below with reference to the attached drawings, provided for illustrative and therefore not limiting purposes only wherein:

[0196] - figure 1 schematically shows a first possible exemplary embodiment of a thermal machine according to the present invention;

[0197] - figure 2 schematically shows a variant of the first embodiment of the thermal machine shown in figure 1 ;

[0198] - figure 3 schematically shows a second possible exemplary embodiment of a thermal machine according to the present invention;

[0199] - figure 4 schematically shows a third possible exemplary embodiment of a thermal machine according to the present invention;

[0200] - figure 5 schematically shows a detail of the power unit of the thermal machine in accordance with the present invention.

[0201] DETAILED DESCRIPTION

[0202] With reference to the above-described figures, with the reference number 100 it has been overall indicated a thermal machine in accordance with the present invention. The thermal machine 100 is depicted in different embodiments and in different variants that differ among them for the presence of additional components and / or for the connections among the various components and / or for the arrangement of said components. Generally, the same reference number is used for identical or similar elements, eventually in their embodiment variants. The thermal machine 100 is first of all configured for realizing a thermodynamic cycle, operating with a thermal fluid. In accordance with what is depicted in the attached figures, the thermal machine 100 comprises a power unit 1. Said power unit 1 comprises:

[0203] - a casing 2 that delimits into its interior at least a first operating chamber 3A and a second operating chamber 3B, different from the first operating chamber 3A;

[0204] - power transformation organs of the thermal fluid, movably housed inside the first operating chamber 3A and the second operating chamber 3B, configured for transforming the thermal power of the thermal fluid in mechanical power, according to an operating cycle, which will be shown in greater detail hereinafter;

[0205] - a drive shaft 8, at least partially housed in the casing 2 and operatively connected to the power transformation organs for connecting between the first operating chamber 3A and the second operating chamber 3B.

[0206] Preferably, the drive shaft 8 is configured for transferring the mechanical power between the first operating chamber 3A and the second operating chamber 3B.

[0207] In a preferred embodiment, the drive shaft 8 is free to rotate around a relative axis of rotation, which preferably coincides with an axis of longitudinal development of the drive shaft itself.

[0208] As shown in detail in figure 5, the first operating chamber 3A presents:

[0209] - a first inlet 4 in fluid communication with a first inlet duct 14 for receiving therefrom a flow of thermal fluid in suction in the first operating chamber 3A;

[0210] - a first outlet 5 in fluid communication with a first outlet duct 15 for sending thereto a flow of thermal fluid in compression exiting from the first operating chamber 3A. With reference still to figure 5, the second operating chamber 3B presents:

[0211] - a second inlet 6 in fluid communication with a second inlet duct 16 for receiving therefrom a flow of thermal fluid in load to be expanded in the second operating chamber 3B;

[0212] - a second outlet 7 in fluid communication with a second outlet duct 17 for sending thereto a flow of thermal fluid to be discharged exiting from the second operating chamber 3B.

[0213] The inlets, the outlets, the inlet ducts, the outlet ducts and the operations performed on the fluid in the first operating chamber 3A (i.e. suction and compression) and in the second operating chamber 3B (i.e. loading, expansion and unloading) are schematically shown in the attached figures, in particular in figure 5.

[0214] In accordance with what is depicted in figures 1-4, the thermal machine 100 comprises a motor circuit 10. In particular, the motor circuit 10 develops between the first inlet 4, the first outlet 5, the second inlet 6 and the second outlet 7 and comprises said first inlet duct 14, first outlet duct 15, second inlet duct 16 and second outlet duct 17.

[0215] Preferably, the motor circuit 10 realizes a continuous flow cycle of the thermal fluid through the power unit 1 , wherein:

[0216] - the second outlet duct 17 starts from the second outlet 7 of the second operating chamber 3B and ends by connecting itself, continuously, with the first inlet duct 14, the latter ending in the first inlet 4 of the first operating chamber 3A;

[0217] - the first outlet duct 15 starts from the first outlet 5 of the first operating chamber 3A and ends by connecting itself, continuously, with the second inlet duct 16, the latter ending in the second inlet 6 of the second operating chamber 3B.

[0218] In accordance with the above, the second outlet duct 17 and the first inlet duct 14 realize a first branch 11 of the motor circuit 10. Analogously, the first outlet duct 15 and the second inlet duct 16 realize a second branch 12 of the motor circuit 10. Preferably, the first branch 11 of the motor circuit is a closed branch and the second branch 12 of the motor circuit is a closed branch.

[0219] Substantially, the first branch 11 is constituted by the union in series of the second outlet duct 17 and of the first inlet duct 14, whereas the second branch 12 is constituted by the union in series of the first outlet duct 15 and of the second inlet duct 16. In the first branch 11 there is continuity (structural and of fluid) between the second outlet duct 17 and the first inlet duct 14, whereas in the second branch 12 there is continuity (structural and of fluid) between the first outlet duct 15 and the second inlet duct 16.

[0220] In accordance with the arrows indicated in figures 1-5, the thermal fluid flows in the motor circuit 10 from the first outlet 5 to the second inlet 6 and from the second outlet 7 to the first inlet 4. It is to be noted that in the description that follows, the terms "upstream” and "downstream” are to be intended referred to a sliding direction of the fluid inside the motor circuit 10 in accordance with the arrows of figures 1-5, i.e. to a direction going from the first outlet 5 to the second inlet 6 and from the second outlet 7 to the first inlet 4.

[0221] The thermal machine 100 comprises, also, a lubrication branch 50. As shown in figures 1-4, the lubrication branch 50 is interposed between the first branch 11 and the second branch 12 of the motor circuit 10. Specifically, the lubrication branch 50 is configured for being affected by a first flow deriving from the thermal fluid circulating in the motor circuit 10. In other words, at least part of the thermal fluid circulating in the motor circuit 10 is temporarily deviated in the lubrication branch 50. As will become clearer in the following, at least part of the thermal fluid circulating in the first branch 11 is introduced in the lubrication branch 50, which subsequently introduces it again in the second branch 12.

[0222] In accordance with the above, the first flow circulating in the lubrication branch 50 coincides at least in part with the thermal fluid circulating in the motor circuit 10. In particular, the first flow comes from the thermal fluid circulating in the motor circuit 10. Therefore, the first flow contains at least a part of the components of the thermal fluid circulating in the motor circuit.

[0223] As shown in figures 1-4, the lubrication branch 50 is active on the casing 2 of the power unit 1 for lubricating at least the drive shaft 8 by means of at least part of the first flow. In the present description, with the term "lubrication” or "lubricating” is intended an activity aimed at promoting the relative movement (for example, the sliding) of two or more elements in contact, typically by means of interposition of appropriate substances that reduce the friction thereof. In this sense, the lubrication branch 50 is suitable for promoting the movement, in particular the rotation, of the drive shaft 8 within the casing 2 by means of the use of the first flow so that the transfer of mechanical power between the first operating chamber 3A and the second operating chamber 3B is more efficient.

[0224] In the embodiments shown in the attached figures, the power unit 1 comprises an outlet shaft Y operatively connected to the power transformation organs. In particular, the outlet shaft Y is configured for receiving the mechanical power produced by the power transformation organs and for providing in outlet a rotating motion, preferably at constant angular speed.

[0225] Preferably, the thermal machine 100 comprises a power generator G, for example an alternator, connected with the outlet shaft Y in such a way as to receive the rotating motion (generated by the power unit 1), preferably at constant angular speed, and generating in outlet electric current suitable for supplying an external utility. Specifically, the outlet shaft Y is cinematically connected to the power transformation organs so as to provide to the power generator G the rotating motion, preferably at constant angular speed, generated jointly by the power transformation organs housed inside the first operating chamber 3A and the second operating chamber 3B. In other words, the power generator G is configured for transforming the mechanical work produced by the power unit (in particular from the part of expansion) in electrical power. In addition, the power generator G can also be arranged to carry out the function of starter engine in the initial start-up step of the power unit 1.

[0226] The thermal machine 10 comprises, preferably, a heater 41 operatively active, along the second branch 12 of the motor circuit 10, between the first outlet duct 15 and the second inlet duct 16. Specifically, the heater 41 is configured for heating the thermal fluid circulating in the second branch 12. It is to be noted that, in the second branch 12, the heater 41 is structurally and operatively interposed between, and divides, the first outlet duct 15 and the second inlet duct 16.

[0227] Preferably, as shown in figures 1-4, the thermal machine 100 comprises a condenser 43, operatively interposed, along the first branch 11 of the motor circuit 10, between the second outlet duct 17 and the first inlet duct 14. In particular, the condenser 43 is configured for cooling the thermal fluid circulating in the first branch 11. It is to be noted that, in the first branch 11 , the condenser 43 is structurally and operatively interposed between, and divides, the second outlet duct 17 and the first inlet duct 14.

[0228] Preferably the thermal machine 100 comprises a condensate separator 93, placed downstream of the condenser 43 along the first inlet duct 14. The condensate separator 93 is configured for separating a liquid component and a gaseous component present in the thermal fluid, before it reaches the first inlet 4 of the first operating chamber 3A. Specifically, the condensate separator 93 is configured for separating, for example by condensation, the liquid component from the gaseous component of the fluid cooled from the condenser 43. As will become clearer hereinafter, the gaseous component is configured preferably for continuing in the motor circuit 10, whereas the liquid component is temporarily deviated in other elements of the thermal machine 100, among which the lubrication branch 50, and then re-enter other points of the motor circuit 10. The condensate separator 93 allows, then, to separate the gaseous component of the mixture (air and / or helium and / or other compatible gas) from the liquid component (condensate water), so as to make them separately usable in the cycle. For convenience, in an absolutely exemplary and non-limiting way, in the present description will be indicated as "water” the liquid component separated by the condenser 93, while the gaseous component will be indicated as "air.” Hereinafter, some components of the fluid that can circulate in the motor circuit 10 will be indicated also herein, in an absolutely exemplary and non-limiting way.

[0229] In accordance with what is shown in figures 1-4, the lubrication branch 50 is operatively connected to the condensate separator 93. Specifically, the first flow circulating in the lubrication branch 50 comprises at least part of the liquid component separated by means of the condensate separator 93. It is to be noted that in the present description, the expression "operatively connected” contemplates both a direct connection, with effective contact among the elements, and an indirect connection, by means of the interposition of other elements suitable for enabling the fluid connection among the elements defined as operatively connected. Therefore, depending on the embodiments of the thermal machine 100, the lubrication branch 50 may be directly connected to the condensate separator 93 or at least one element may be interposed between the lubrication branch and the condensate separator in order to ensure the fluid connection.

[0230] As shown in the embodiments of the attached figures, the lubrication branch 50 comprises at least:

[0231] - a supply duct 51 configured for receiving the first flow from the first branch 11 ;

[0232] - a return duct 53 configured for introducing the first flow in the second branch 12;

[0233] - a lubrication segment 52 interposed between, and in fluid communication with, the supply duct 51 and the return duct 53.

[0234] In use, the lubrication segment 52 is configured for receiving at least a part of the first flow circulating inside the supply duct 51 and for sending said portion of first flow to the return duct 53.

[0235] The lubrication segment 52 defines a lubrication compartment 520 configured for housing, at least partially, the drive shaft 8. Specifically, the compartment 520 is configured for surrounding the drive shaft 8. In other words, the lubrication compartment 520 is obtained inside the casing 2 and is configured for housing, at least partially and in a movable way, the drive shaft 8, defining around it a gap suitable for being affected by at least part of the first flow in inlet through the supply duct 51 . Preferably, the thermal machine 100 comprises a vaporization pipeline 20 that develops from the condensate separator 93 to the second branch 12, preferably in a point of the first outlet duct 16, i.e. upstream of the heater 41 . Analogously to the lubrication branch 50, also the vaporization pipeline 20 is preferably configured for being affected by at least part of the liquid component separated by the condensate separator 93.

[0236] Preferably, the thermal machine comprises a first pump 94 (preferably at high pressure), configured for withdrawing at least a part of the liquid component separated by the condensate separator 93 and for sending it in the vaporization pipeline 20 confluent in the second branch 12.

[0237] Preferably, as shown in figures 1-4, the thermal machine 100 comprises a vaporizer 95, positioned in a position so as to:

[0238] - intercept, from a high temperature side thereof (or first side), the second outlet duct 17 downstream of the power unit 1 and upstream of the condenser 43; and

[0239] - intercept, from a low temperature side thereof (or second side), the vaporization pipeline 20.

[0240] Preferably, the vaporizer 95 is configured for heating and vaporizing the liquid component circulating in the vaporization pipeline 20 before it flows in the second branch 12. Substantially, the vaporizer 95 (which constitutes a vapour generator) is capable of subtracting (in the high temperature side thereof) a large part of the residual thermal power contained in the thermal fluid unloaded from the second outlet 7 after the expansion and of transferring (in the low temperature side thereof) said thermal power to the fluid circulating in the vaporization pipeline, generating superheated vapour to be re-introduced in the motor circuit upstream of the heater 41.

[0241] Preferably, the thermal machine 100 comprises a first injector 97, placed at the end of the vaporization pipeline 20 and configured for injecting in the second branch 12, upstream of the heater 41 , a predefined quantity of the liquid component vaporized in the vaporizer so as to increase the unitary power of the power unit 1 .

[0242] Preferably, the vaporizer 95 is operatively interposed, on the low temperature side thereof, between the first pump 94 and the first injector 97, and is operatively interposed, on the high temperature side thereof, between the second outlet 7 of the power unit 1 , that expels the exhausted thermal fluid, and the condenser 43. In said configuration, the vaporizer acquires residual power (i.e., heat) from the exhausted thermal fluid and uses it for pre-heating the thermal fluid in transit towards the heater 41.

[0243] Preferably, the vaporizer 95 is a heat exchanger, provided with two sides that intercept - respectively - the second outlet duct 17 (downstream of the power unit 1 and upstream of the condenser 43) and the vaporization pipeline 20 so as to transfer heat from the thermal fluid circulating in the second outlet duct 17 (cooling it) to the fluid circulating in the vaporization pipeline 20 (heating it and vaporizing it).

[0244] It is to be noted that the function performed by the vaporizer 95 is to allow to recover the energetic differential between the temperature of the thermal fluid at the end of expansion (unloaded from the second outlet 7 of the second operating chamber 3B) and the temperature of the same to the almost complete condensation (measured at the outlet of the condensate separator 93 on the vaporization pipeline 20). In fact, the temperature at the end of expansion can be particularly high (for example, 360°C) whereas the temperature at the outlet of the condenser can be considerably lower (for example, 40°C). If the thermal power of the fluid at the end of expansion would not be used in the vaporizer 95, said thermal power would be dissipated for no useful purpose in the condenser 43. On the contrary, the presence of the vaporizer 95 transforms the liquid component in outlet from the condensate separator 93 in superheated vapour, fully reusable in the motor circuit 10 to increase the yield of the thermal machine 100.

[0245] It is to be noted that the first injector 97 is the point wherein the vaporization pipeline 20 flows in the second branch 12 of the motor circuit 10. The first injector 97 acts as a "mixing box or lung” that receives at least the thermal fluid in outlet (after the compression) from the first outlet 5, brought from the first outlet duct 15 (coming therefore from the part of compression of the first operating chamber 3A), and the mixture with the vaporized fluid transported by the vaporization pipeline 20 after the transit in the vaporizer 95.

[0246] As shown in the embodiments of the attached figures, the return duct 53 of the lubrication branch 50 ends in a point of the first outlet duct 15 upstream of the heater 41 . Preferably, the return duct 53 ends at the first injector 97.

[0247] In a first variant of the thermal machine 100, shown by way of example in the embodiments of figures 1 and 3, the lubrication branch 50 starts at the condensate separator 93. In accordance with said configuration, the lubrication branch 50 is directly connected to the first branch 11 , in particular to the condensate separator 93. Specifically, the supply duct 51 is in direct fluid communication with the condensate separator 93. More in detail, both the supply duct 51 and the vaporization pipeline 20 are directly connected to the condensate separator 93 to be affected by at least a part of the liquid component separated by the same condensate separator.

[0248] In the configuration of figures 1 and 3, the lubrication branch 50 comprises a second pump 54, preferably positioned on the inlet branch 51 and configured for withdrawing at least a part of the liquid component from the condensate separator 93. Therefore, a part of the liquid component is withdrawn by the first pump 94 and is sent on the vaporization pipeline 20 toward the vaporizer, whereas another part (for example, the remaining part of the liquid component separated by the condensate separator 93) is withdrawn by the second pump 54 and sent to the supply duct 51 for constituting the first fluid flow circulating in the lubrication branch.

[0249] In a second variant of the thermal machine 100, shown by way of example in the embodiments of figures 2 and 4, the vaporization pipeline 20 comprises a first diverter valve 55. In said variant, the supply duct 51 starts at the first diverter valve 55. Therefore, in the embodiments in accordance with figures 2 and 4, the lubrication branch 50 is indirectly connected to the first branch 11 , in particular to the condensate separator 93. Specifically, a portion of the vaporization pipeline, equivalent to the section that goes from the condensate separator 93 to the first diverter valve 55, is interposed between the supply duct 51 and the condensate separator. Then, the supply duct 51 is in fluid communication only indirectly with the condensate separator 93, as solely the vaporization pipeline 20 is directly connected to the condensate separator 93.

[0250] The first diverter valve 55 is configured for distributing between the vaporization pipeline 20 and the supply duct 51 the liquid component withdrawn from the condensate separator 93 by means of the first pump 94. Specifically, the first diverter valve 55 is configured for sending the first flow to the lubrication branch 50, in particular to the supply duct 51, and for sending a second flow to a remaining portion of the vaporization pipeline 20 downstream of the first diverter valve itself. Therefore, the first flow and the second flow constitute together the liquid component withdrawn from the condensate separator 93 by means of the first pump 94. In other words, the first pump 94 withdraws at least part of the liquid component present in the condensate separator 93 and sends it to the first diverter valve 55, which is configured for distributing it between the lubrication branch 50 and the vaporization pipeline 20. The part of liquid component that is sent to the lubrication branch 50 coincides with the first flow, which affects the lubrication compartment 520 wherein is at least partially housed the drive shaft 8; the remaining part of the liquid component is sent to the vaporization pipeline 20, generating the second flow that subsequently affects the vaporizer 95.

[0251] Preferably, as shown in the embodiment shown in figure 3, the lubrication branch 50 comprises a cooling segment 56, which is operatively active on the casing 2. Analogously to the lubrication segment 52, the cooling segment 56 is configured for being affected by at least a part of the first flow for a thermal exchange with the casing 2. Specifically, the cooling segment 56 is configured for withdrawing heat from the casing 2. In other words, the cooling segment 56 is operatively active on the casing 2 for cooling it.

[0252] In accordance with what is shown in figure 3, the cooling segment 56 is interposed between the supply duct 51 and the return duct 53 of the lubrication branch 50. In particular, the cooling segment 56 is in fluid communication with the supply duct 51 and with the return duct 53. In detail, the cooling segment 56 is configured for receiving from the supply duct 51 at least part of the first flow and for re-introducing said part of the first flow in the return duct 53.

[0253] Preferably, the lubrication branch 50 comprises a second diverter valve 57 interposed between the supply duct 51 , the lubrication segment 52 and the cooling segment 56. Specifically, the supply duct 51 ends in the second diverter valve, whereas the lubrication segment 52 and the cooling segment 56 start from the second diverter valve. The second diverter valve 57 is configured for distributing the first flow circulating in the supply duct 51 between the lubrication segment 52 and the cooling segment 56. In other words, the second diverter valve 57 receives the first flow from the supply duct 51 and distributes it between the lubrication segment 52 and the cooling segment 56: a part of the first flow is sent to the lubrication segment 52 for affecting the lubrication compartment 520 so as to lubricate the drive shaft 8, whereas the remaining part of first flow is sent to the cooling segment 56 for a heat exchange with the casing 2 of the power unit 1 .

[0254] Preferably, the lubrication branch 50 comprises a second injector 58 interposed between the return duct 53, the lubrication segment 52 and the cooling segment 56. Specifically, the lubrication segment 52 and the cooling segment 56 end in the second injector, whereas the return duct 56 starts from the same second injector. The second injector 58 is configured for receiving fluid flows from the lubrication segment 52 and from the cooling segment 56 and for conveying such fluid flows in the return duct 53. On the basis of the connections among the various elements of the lubrication branch 50, the sum of the fluid flows entering the second injector 57 coincides substantially with the first flow circulating in the supply duct 51 . In other words, the flows sent from the second diverter valve 57 on the lubrication segment 52 and on the cooling segment 56 are then collected by the second injector 58 and sent to the return duct 53, to be eventually re-introduced in the second branch 12 of the motor circuit 10 through the first injector 97. Additional optional components of the thermal machine 100 will now be described in accordance with the present invention. With reference to figure 4, the following components are depicted simultaneously installed in the thermal machine 100 in accordance with the variant of the thermal machine shown in figure 2. It is to be noted that each of the following optional components can be installed independently of the other components. Also, the depiction of figure 4 is to be intended absolutely in an exemplary and non-limiting way as the following optional components can be adapted and installed also in the variant of the thermal machine according to figures 1 and 3.

[0255] Preferably, as shown for example in figure 4, the thermal machine comprises a compensation lung 44 positioned downstream of the first outlet 5 of the power unit along the first outlet duct 15 and configured for:

[0256] - accumulating the compressed thermal fluid and making it available for its later use;

[0257] - balancing and optimizing the flow of thermal fluid circulating in the motor circuit 10.

[0258] Preferably, the heater 41 comprises a burner 40 provided with a containment body 410 defining a combustion chamber 40A. The burner 40 is configured for being supplied with a plurality of fuel typologies and for providing the heater 41 with the thermal power necessary to its functioning. Preferably, the containment body 410 is provided with a combustion air inlet 411 , typically withdrawn from the environment.

[0259] Preferably, the heater 41 comprises an injection valve configured for managing in a controlled way the introduction of fuel to feed the burner.

[0260] As shown in figure 4, the containment body 410 houses both the burner 40, operatively active along the second branch 12 of the motor circuit 10, and the condenser 43, operatively active along the first branch 11 of the motor circuit 10. With reference to the arrangement of the condenser 43 and of the burner 40 inside the containment body 410 shown, the heat withdrawn from the first branch 11 through the condenser 43 is transferred to the combustion air before it reaches the burner 40, promoting the combustion process and reducing the power requirement needed to the heating of the thermal fluid in the second branch 12.

[0261] It is to be noted that the containment body 410 defines a direction of the flow of the combustion air in the burner 40 that goes from the condenser 43 to the heater 41 , represented by the arrows at the air inlet 411 of the containment body 410 in figure 4.

[0262] Preferably, the thermal machine 100 comprises a superheater 96 positioned downstream of the burner 40 with respect to the direction of the flow of the combustion air. The superheater 96 is configured for subtracting power from the hot combustion fumes of the burner and for intercepting the vaporization pipeline 20, in a position downstream of the low temperature side of the vaporizer 95 and upstream of the first injector 97. In particular, the superheater 96 is configured for transferring the power subtracted from the hot combustion fumes of the burner to the fluid vaporized in outlet from the vaporizer 95, in such a way as to overheat it before it reaches the first injector 97.

[0263] Preferably, the thermal machine 100 is provided with a closed cooling circuit 60, different from the motor circuit. In the embodiment shown, the cooling circuit 60 comprises a first heat recovery device 98, preferably positioned in the containment body 410 of the heater 41 in a position downstream of the condenser 43 and upstream of the burner 40, with respect to the direction of the flow of the combustion air. Preferably, the cooling circuit 60 comprises a cooling unit 2R operatively associated to the casing 2 of the power unit 1 . By way of example, the cooling unit 2R can be a gap externally associated to the casing 2 of the power unit 1 , for example in contact with at least a portion of the casing 2. According to the embodiments, the cooling unit 2R is configured for cooling the casing 2, in addition or in replacement of the cooling segment 56 of the lubrication branch 50.

[0264] Preferably, the cooling circuit 60 comprises a plurality of cooling ducts connecting in series, forming a circular path, the first heat recovery device 98 and the cooling unit 2R suitable for allowing the flow a quantity of cooling fluid, for example water.

[0265] Preferably, the cooling circuit 60 comprises a cooling pump 99, placed in the cooling circuit and operatively active on one of the cooling ducts to determine a circulation of the cooling fluid in the cooling circuit 60.

[0266] Preferably, the cooling circuit 60 comprises a second heat recovery device 61 , preferably positioned in the containment body 410 in a position downstream of the burner 40 with respect to the direction of the flow of the combustion air. In the embodiment of figure 4, the second heat recovery device 61 is positioned downstream also of the superheater 96 with respect to the direction of the flow of the combustion air.

[0267] Preferably, the plurality of cooling ducts connects in series the first heat recovery device 98, the cooling unit 2R and the second heat recovery device 61 , the latter resulting interposed downstream of the cooling unit 2R and upstream of the first heat recovery device 98 with respect to the direction of the flow of the combustion air. In said configuration:

[0268] - in the cooling unit 2R the low temperature cooling fluid withdraws heat from the casing 2 of the power unit 1 , cooling it, and consequently is brought to high temperature;

[0269] - in the second heat recovery device 61 the high temperature cooling fluid acquires heat from the hot combustion fumes, cooling them, and consequently undergoes a further increase in temperature;

[0270] - in the first heat recovery device 98 the high temperature cooling fluid transfers heat to the flow of the combustion air (before it enters the burner 40), heating it, and consequently returns to low temperature.

[0271] Still with reference to the embodiment of figure 4, the thermal machine 100 can be provided with an auxiliary hydraulic circuit comprising an auxiliary recovery device 201, preferably positioned in the containment body of the heater in a position downstream of the burner 40 with respect to the direction of the flow of the combustion air. Still preferably, the auxiliary recovery device 201 is positioned downstream also of the superheater 96 with respect to the direction of the flow of the combustion air.

[0272] Preferably, the auxiliary hydraulic circuit comprises a plurality of auxiliary pipelines configured for passing through the auxiliary recovery device 201 and for being connected with one or more auxiliary uses 202, preferably environmental heating users and / or sanitary hot water production units.

[0273] Still preferably, the auxiliary hydraulic circuit comprises an auxiliary pump 203, placed in the auxiliary hydraulic circuit and operatively active on one of the auxiliary pipelines to determine the circulation of fluid in the auxiliary hydraulic circuit. Preferably, the auxiliary recovery device 201 is configured for recovering power from the combustion fumes and for transmitting it to the fluid circulating in the auxiliary hydraulic circuit so that it is available for the auxiliary uses 202. Preferably, the thermal machine 100 comprises a fan, not shown, placed at the combustion air inlet 411 of the containment body 410 of the heater and configured for withdrawing combustion air from the environment and sending it forcibly to the burner 40 to supply the combustion process.

[0274] Preferably, the thermal machine 100 can comprise one or more non-return valves, for example of known type, placed along the pipelines of the motor circuit of the thermal machine. The non-return valves are configured for promoting the circulation of the thermal fluid in a unidirectional way and for preventing the outflow of the thermal fluid in opposite direction.

[0275] Preferably, as shown schematically in figure 5, the power transformation organs are configured for transforming the power of the thermal fluid in mechanical power according to an operating cycle that provides a sequence of steps of:

[0276] - suction of thermal fluid in the first operating chamber 3A (through the first inlet 4);

[0277] - compression of the thermal fluid in the first operating chamber 3A and emission (i.e. outlet) of the thermal fluid (through the first outlet 5);

[0278] - loading of thermal fluid in the second operating chamber 3B (through the second inlet 6) and expansion of the thermal fluid in the second operating chamber 3B;

[0279] - unloading of thermal fluid from the second operating chamber 3B (through the second outlet 7).

[0280] By way of example, the power unit 1 is a thermal engine comprising a compressor, carrying out the steps of suction and compression, and an expander, carrying out the steps of loading, expansion and unloading. The compressor and the expander are mechanically connected with each other through the drive shaft 8. Preferably, the compressor is a multi-stage rotary compressor and the expander is a turbine expander.

[0281] In the embodiment shown in detail of figure 5, in the first operating chamber 3A, provided with the first inlet 4 and of the first outlet 5, occur the suction of the thermal fluid and the compression of the thermal fluid, whereas in the second operating chamber 3B, provided with the second inlet 6 and of the second outlet 7, occur the loading of the compressed thermal fluid, the expansion of the thermal fluid and the unloading of the thermal fluid. Substantially, each of the operating chambers is intended to carry out a respective half of the operating cycle.

[0282] In an embodiment, the power unit 1 is a continuous flow power unit, wherein:

[0283] - the first operating chamber 3A is structured for realizing a compressor, configured for operating a suction of fluid and a compression of fluid;

[0284] - the second operating chamber 3B is structured for realizing a turbine, configured for operating a loading of fluid, an expansion of fluid and an unloading of fluid.

[0285] In another embodiment, the power unit 1 can be an intermittent flow power unit, wherein:

[0286] - the first operating chamber 3A is a variable volume operating chamber, configured for operating a suction of fluid and a compression of fluid;

[0287] - the second operating chamber 3B is a variable volume operating chamber, configured for operating a loading of fluid, an expansion of fluid and an unloading of fluid. At the state of the art, some known typologies of endothermic (internal combustion) engines, with appropriate mechanical and functional modifications, can be adapted for the use as power units 1. By way of illustrative, and non-limiting, example the following engines are listed:

[0288] - Diesel four-stroke reciprocating engine;

[0289] - Otto four-stroke reciprocating engine;

[0290] - Wankel four-stroke rotary engine;

[0291] - Quasiturbine four-stroke rotary engine (patent US-2014-0140879-A1).

[0292] At the state of the art, some known typologies of exothermic (external combustion) engines, with appropriate mechanical and functional modifications, can be adapted for the use as power units 1. By way of illustrative, and non-limiting, example the following engines are listed:

[0293] - RVE rotary engine, consisting of a Suction-Compression section and a or two Expansion-Discharge sections, bounded by four or six sliding pistons, with periodically variable speed, within a single annular cylinder, as already described in patent applications WO2015 / 114602A1 and WO2019 / 008457, on behalf of the same Applicant;

[0294] - Ericsson two-cylinder reciprocating engine;

[0295] - Wankel rotary engine, formed by a Compressor and by an Expander, mechanically connected with each other by any transmission system (patent: US3,426,525);

[0296] - rotary vane engine; formed by a Compressor and by an Expander, mechanically connected with each other by any transmission system (patent: DE4317690A1 );

[0297] - trilobe rotary motor; formed by a Compressor and by an Expander, mechanically connected with each other by any transmission system (patent: US20110259002A1);

[0298] - RVE rotary engine; formed by a Compressor and by an Expander, mechanically connected with each other by an appropriate transmission system (patent: WC02084078A1);

[0299] - rotary Scroll motor, formed by a Compressor and by an Expander, mechanically connected with each other by an appropriate transmission system (patent: US20050172622A1 );

[0300] - Multi-stage Turbine rotary engine, formed by a compressor and by an Expander, mechanically connected with each other by an appropriate transmission system (patent: WC2012123500A2).

[0301] In the context of the present invention, said thermal fluid circulating in the motor circuit 10 and lubrication branch 50 is a mixture comprising a gas and water vapour or water. According to the embodiments, the gas used in the thermal machine can be air or helium or another gaseous fluid (or mixture of gaseous fluids) compatible with the water vapour or the water, and the thermodynamic cycle realized by the thermal machine is a combined thermodynamic cycle.

[0302] It is to be noted that, in a "rest” condition of the thermal machine, the fluids used (for example, air and water) are to the same temperature as the surroundings and that, during the operation, inside the power unit 1 , of the motor circuit 10 and of the lubrication branch 50 there may be pressures other than the atmospheric one.

[0303] It is to be noted that the thermal machine 100 comprises appropriate control and regulating equipment (for example a suitably programmed electronic control unit), not shown as known in the technique. Also, the thermal machine 100 comprises preferably means for starting-up configured for handling the steps of initialization of the operating cycle and of ignition of the various components of the thermal machine (start-up power unit 1 , heater 41 , circulation of the thermal fluid, etc.).

[0304] It is hereinafter described the method for realizing a thermodynamic cycle in accordance to the present description. This method operates with a thermal fluid and comprises first of all the following steps:

[0305] - arranging a thermal machine 100 in accordance with what has been previously described, for example a thermal machine 100 according to the embodiments shown in figures 1-4;

[0306] - starting the power unit 1 , putting in motion the power transformation organs of the thermal fluid;

[0307] - activating an operating cycle.

[0308] Specifically, the step of activating the operating cycle comprising the following steps:

[0309] - sucking the thermal fluid in the first operating chamber 3A through the first inlet 4;

[0310] - compressing the thermal fluid in the first operating chamber 3A and emitting the thermal fluid from the first outlet 5;

[0311] - heating the thermal fluid circulating in the second branch 12 of the motor circuit 10 by means of the heater 41;

[0312] - loading the thermal fluid in the second operating chamber 3B through the second inlet 6 and expanding the thermal fluid in the second operating chamber 3B;

[0313] - unloading the thermal fluid from the second operating chamber 3B through the second outlet 7.

[0314] The operating cycle steps of sucking, compressing, loading, expanding and unloading the thermal fluid determine a transformation of the thermal power of the thermal fluid in mechanical power.

[0315] The method for realizing a thermodynamic cycle comprises, also, the steps of:

[0316] - sending to the lubrication branch 50 the first fluid flow deriving from the thermal fluid circulating in the motor circuit 10;

[0317] - lubricating the drive shaft 8 by means of at least part of the first flow;

[0318] - feeding the first flow in the second branch 12 (preferably at least before the step of loading the thermal fluid in the second operating chamber 3B through the second inlet 6).

[0319] Preferably, the method comprises the step of transferring the mechanical power generated from the transforming organs to the outlet shaft 8, which supplies in outlet a rotating motion preferably at constant angular speed.

[0320] Still preferably, the step of starting the power unit 1 is carried out in a substantially contextual way to the following steps:

[0321] - activating the heater 41 for heating the thermal fluid in the motor circuit 10;

[0322] - activating the condenser 43 for cooling the thermal fluid;

[0323] - activating the condensate separator for separating the liquid component from the gaseous component of the thermal fluid.

[0324] Preferably, in the embodiments of the thermal machine that comprise also the vaporization pipeline 20 and the vaporizer 95, the method comprises also the following steps: - the thermal fluid in outlet from the second outlet 7 of the power unit 1 transits in the second outlet duct 17 of the first branch 11 of the motor circuit 10 and passes through the high temperature side of the vaporizer 95;

[0325] - the thermal fluid continues in the first branch 11 and reaches the condenser 43 wherein is cooled;

[0326] - the thermal fluid continues in the first branch 11 and reaches the condensate separator 93 wherein the liquid component present in the thermal fluid is condensed and separated by the gaseous component, before the thermal fluid reaches the first inlet 4 of the power unit;

[0327] - at least part of the liquid component of the thermal fluid separated by the condensate separator 93 is sent in the vaporization pipeline 20, whereas the remaining part is sent in the supply duct 51 of the lubrication branch 50;

[0328] - the liquid component circulating in the vaporization pipeline 20 passes through the low temperature side of the vaporizer, wherein is heated and vaporized before it flows in the second branch 12;

[0329] - the liquid component vaporized is introduced in the second branch 12, upstream of the heater 41 , through the first injector 97, in order to increase the unitary power of the power unit 1 .

[0330] In an embodiment, the method comprises a step of cooling the casing 2 of the power unit 1 by means of the cooling segment 56. In said embodiment, the method comprises a step of distributing the first flow sent in the supply duct 51 between the lubrication segment 52 and the cooling segment 56. Preferably, the step of distributing is carried out from the second diverter valve 57. Symmetrically, the method comprises also a step of conveying in the return duct 53 the flows distributed on the lubrication segment 52 and on the cooling segment 56. Still preferably, the step of conveying is carried out from the second injector 58.

[0331] In the embodiments of the thermal machine 100 in accordance with figure 4, the method can comprise the following steps:

[0332] - the second flow in the vaporization duct 20, after passing through the low temperature side of the vaporizer 95, wherein is heated and vaporized, reaches the superheater 96, placed upstream of the first injector 97 (i.e. between vaporizer 95 and first injector 97), which transfers heat to the liquid component vaporized in such a way as to overheat it before it reaches the first injector 97.

[0333] In the embodiments of the thermal machine 100 in accordance with figure 4, the method can provide for arranging a cooling circuit 60, comprising the first recovery device 98, the cooling unit 2R, the plurality of cooling ducts and the cooling pump 99. In said circumstance, the method provides preferably for carrying out the following steps:

[0334] - the low temperature cooling fluid interacts with the cooling unit 2R, wherein withdraws heat from the casing 2 of the power unit 1 , cooling it, and consequently is brought to high temperature;

[0335] - the high temperature cooling fluid interacts with the first heat recovery device 98, wherein transfers heat to the flow of the combustion air, heating it, and consequently cools and returns to low temperature;

[0336] - activating the cooling pump 99 for determining the circulation of cooling fluid in the cooling circuit 60.

[0337] Still preferably, the method can provide for arranging the second heat recovery device 61 inside the cooling circuit 60, and carrying out the following steps: - in the cooling unit 2R the low temperature cooling fluid withdraws heat from the casing 2 of the power unit 1 , cooling it, and consequently is brought to high temperature;

[0338] - in the second heat recovery device 61 the high temperature cooling fluid acquires heat from the hot combustion fumes, cooling them, and consequently undergoes a further increase in temperature;

[0339] - in the first heat recovery device 98 the high temperature cooling fluid transfers heat to the flow of the combustion air (before its inlet in the burner), heating it, and consequently cools and returns to low temperature. Preferably, the method can provide for arranging an auxiliary hydraulic circuit, comprising the auxiliary recovery device 201 , the plurality of auxiliary pipelines and the auxiliary pump 203, and for carrying out the following steps:

[0340] - recovering from the combustion fumes, through the auxiliary recovery device 201 , a quantity of power;

[0341] - transmitting said power to the fluid circulating in the auxiliary circuit;

[0342] - making available the power for auxiliary uses 202.

[0343] ADVANTAGES OF THE FINDING

[0344] The invention achieves important advantages. First, as it is clear from the above description, the invention allows to overcome at least some of the drawbacks of the known technique.

[0345] In particular, the thermal machine and the relative method according to the present description allow to integrate, in the thermodynamic cycle operated by the machine, also the functions of lubrication of the drive shaft 8. In particular, with respect to known solutions that already integrate lubrication functions of the drive shaft of the power unit, the present thermal machine does not require an additional circuit specially dedicated to the lubrication of the means of transmission of the motion between the operating chambers of the power unit. Specifically, the integration of the lubrication branch 50 in communication with the motor circuit 10 allows to increase the overall efficiency of the thermodynamic cycle, thanks to the decrease of the frictions in the transmission of the mechanical power between the operating chambers 3A, 3B of the power unit 1, guaranteeing, at the same time, a greater constructive simplicity than traditional thermal machines that provide an additional circuit opportunely dedicated to the lubrication of the drive shaft.

[0346] Also, the thermal machine and the method according to the present invention guarantee a high reliability. In fact, thanks to the presence of the lubrication branch 50 active on the casing 2 and on the drive shaft 8 housed therein, it is possible to keep perfectly lubricated, and eventually also cooled, the transmission components of the motion between the operating chambers 3A, 3B minimizing the frictions that could cause inefficiency and / or malfunction of the power unit.

[0347] The constructive simplicity and the rational structure of the thermal machine according to the present invention allow to offer a device characterized by a high power-to-weight ratio. In fact, in addition to increasing the efficiency of the thermodynamic cycle due to the reduction of frictions in the transmission of the motion, the integration of the lubrication branch 50 in the motor circuit 10 allows to significantly reduce the weight of the thermal machine, especially with respect to the solutions that provide for an independent lubrication system. At the same time, the lack of a separate plant solely dedicated to the lubrication of the drive shaft 8 allows to produce the machine according to the present invention at a reduced cost. Specifically, the integration of the lubrication branch 50 into the motor circuit 10 allows to avoid the redundancy of components, thanks to the use of the traditional elements of the motor circuit 10 with dual function. Consequently, a lower number of components also ensures a greater reliability of the thermal machine since the sources of possible malfunction and / or failure are decreased.

[0348] Also, it is to be noted that the thermal machine and the method according to the present invention use a single thermal fluid for both the execution of the thermodynamic cycle and for the lubrication, and eventually for the cooling, of the components of the power unit. In this sense, the maintenance operations of the thermal machine are greatly simplified because, unlike known solutions that use oil lubrication systems, it is not necessary to provide for the periodic control and replacement operations of the lubricating fluid.

[0349] In addition, the thermal machine and the relative method object of the present document allow to realize a thermodynamic cycle in almost any location and for any use, preferably for the production of electrical power by means of the coupling between the power production organs and a power generator, for example an alternator.

[0350] Finally, the vaporizer allows to obtain an increase of the overall efficiency, as the amount of heat absorbed by the evaporation is compensated from the power recovery implemented with the vaporizer.

Claims

CLAIMS1. Thermal machine (100) configured for realizing a thermodynamic cycle, the thermal machine operating with a thermal fluid and comprising:- a power unit (1) comprising:- a casing (2) delimiting into its interior:- a first operating chamber (3A) having a first inlet (4), in fluid communication with a first inlet duct (14) for receiving therefrom a flow of said thermal fluid in suction, and a first outlet (5), in fluid communication with a first outlet duct (15) for sending thereto a flow of said thermal fluid in compression;- a second operating chamber (3B), different from said first operating chamber (3A), having a second inlet (6), in fluid communication with a second inlet duct (16) for receiving therefrom a flow of said thermal fluid in load to be expanded, and a second outlet (7), in fluid communication with a second outlet duct (17) for sending thereto a flow of said thermal fluid to be discharged;- power transformation organs of said thermal fluid, movably housed within said first operating chamber (3A) and said second operating chamber (3B), configured for transforming the power of said thermal fluid in mechanical power, according to an operating cycle;- a drive shaft (8) at least partially housed in said casing (2), said drive shaft (8) being operatively connected to said power transformation organs and configured for connecting said first operating chamber (3A) and said second operating chamber (3B) with each other;- a motor circuit (10) developing between said first inlet (4), said second inlet (6), said first outlet (5) and said second outlet (7) and comprising said first inlet duct (14), said first outlet duct (15), said second inlet duct (16) and said second outlet duct (17), said motor circuit (10) realizing a continuous cycle of flow of said thermal fluid through said power unit (1), wherein:- said second outlet duct (17) starts from said second outlet (7) and ends by connecting itself, continuously, with said first inlet duct (14), the latter ending in said first inlet (4), the second outlet duct and the first inlet duct realizing a first branch (11) of the motor circuit (10);- said first outlet duct (15) starts from said first outlet (5) and ends by connecting itself, continuously, with said second inlet duct (16), the latter ending in said second inlet (6), the first outlet duct and the second inlet duct realizing a second branch (12) of the motor circuit (10);- said thermal fluid flows in said motor circuit (10) from said first outlet (5) a said second inlet (6) and from said second outlet (7) a said first inlet (4);- a lubrication branch (50) operatively interposed between said first branch (11) and said second branch (12), said lubrication branch (50) being configured for being affected by a first fluid flow deriving from said thermal fluid, said lubrication branch (50) being active on said casing (2) for lubricating at least said drive shaft (8) by means of at least part of said first flow.

2. Thermal machine (100) according to claim 1 comprising at least:a heater (41) operatively active, along said second branch (12) of the motor circuit (10), between said first outlet duct (15) and said second inlet duct (16), configured for heating the thermal fluid circulating in the second branch (12) of the motor circuit; a condenser (43), operatively interposed, along said first branch (11) of the motor circuit (10), between said second outlet duct (17) and said first inlet duct (14), configured for cooling the thermal fluid circulating in the first branch (11); a condensate separator (93), placed downstream of the condenser (43) along said first inlet duct (14), said condensate separator (93) being configured for separating a liquid component and a gaseous component present in the thermal fluid before it reaches said first inlet (4); and / or wherein said lubrication branch (50) is operatively connected to said condensate separator (93), said first flow circulating in said lubrication branch (50) comprising at least part of the liquid component separated by said condensate separator (93); and / or wherein said lubrication branch (50) comprises: a supply duct (51) configured for receiving said first flow; a return duct (53) configured for introducing said first flow in said second branch (12); a lubrication segment (52) interposed between, and in fluid communication with, said supply duct (51) and said return duct (53), said lubrication segment (52) defining a compartment (520) configured for housing, at least partially, and surrounding said drive shaft (8); and / or wherein said lubrication segment (52) is configured for receiving at least a part of said first flow from said supply duct (51) and for sending said at least a part of said first flow to said return duct (53).

3. Thermal machine (100) according to claim 1 or 2, comprising: a vaporization pipeline (20) extending between said condensate separator (93) and said second branch (12), in a point of said first outlet duct (15) upstream of said heater (41), said vaporization pipeline (20) being configured for being affected by at least part of the liquid component present in said condensate separator (93); a first pump (94), configured for withdrawing at least part of the liquid component from said condensate separator (93) and for sending in said vaporization pipeline (20); a vaporizer (95), positioned in the thermal machine in such a way as to intercept, from a high temperature side thereof, said second outlet duct (17) and, from a low temperature side thereof, said vaporization pipeline (20), said vaporizer (95) being configured for heating and vaporizing the liquid component circulating in said vaporization pipeline (20) before it flows in said second branch (12); a first injector (97), placed at the end of said vaporization pipeline (20) and configured for injecting in said second branch (12), upstream of the heater (41), said liquid component vaporized by said vaporizer (95); and / or wherein the vaporizer (95) is operatively interposed, on the low temperature side thereof, between said first pump (94) and said first injector (97), and is operatively interposed, on the high temperature side thereof, between said second outlet (7) and said condenser (43);and / or wherein said return duct (53) ends in a point of said first outlet duct (15) upstream of said heater (41), preferably at said first injector (97).

4. Thermal machine (100) according to the preceding claim, wherein said lubrication branch (50) starts at said condensate separator (93), said supply duct (51) being in fluid communication with said condensate separator (93); and / or wherein said lubrication branch (50) comprises a second pump (54) configured for withdrawing at least a part of the liquid component from said condensate separator (93), said at least a part of the liquid component withdrawn by the second pump (54) coinciding with said first flow; and / or wherein said second pump (54) is operatively active on said supply duct (51) for generating said first flow along said lubrication branch (50).

5. Thermal machine (100) according to claim 3, wherein said vaporization pipeline (20) comprises a first diverter valve (55), said supply duct (51) starting from said first diverter valve (55); and / or wherein said first diverter valve (55) is configured for distributing between said vaporization pipeline (20) and said supply duct (51) the liquid component withdrawn, by means of said first pump (94), from said condensate separator (93); and / or wherein said first diverter valve (55) is configured for sending said first flow to said lubrication branch (50), in particular to said supply duct (51), and for sending a second flow to a remaining portion of said vaporization pipeline (20) downstream of said diverter valve, said first flow and said second flow constituting together the liquid component withdrawn, by means of said first pump (94), from said condensate separator (93).

6. Thermal machine (100) according to claim 4 or 5, wherein said lubrication branch (50) comprises a cooling segment (56) operatively active on said casing (2), said cooling segment (56) being configured for being affected by at least a part of said first flow for a thermal exchange with said casing (2); and / or wherein said cooling segment (56) is configured for withdrawing heat from said casing (2); and / or wherein said cooling segment (56) is interposed between said supply duct (51) and said return duct (53); and / or wherein said cooling segment (56) is in fluid communication with said supply duct (51) and with said return duct (53).

7. Thermal machine (100) according to the preceding claim, wherein said lubrication branch (50) comprises a second diverter valve (57) interposed between said supply duct (51), said lubrication segment (52) and said cooling segment (56); and / or wherein said supply duct (51) ends in said second diverter valve (57) and wherein said lubrication segment (52) and said cooling segment (56) start from said second diverter valve (57); and / or wherein said second diverter valve (57) is configured for distributing said first flow between said lubrication segment (52) and said cooling segment (56); and / or wherein said lubrication branch (50) comprises a second injector (58) interposed between said return duct (53), said lubrication segment (52) and said cooling segment (56);and / or wherein said lubrication segment (52) and said cooling segment (56) end in said second injector (58) and wherein said return duct (53) starts from said second injector (58); and / or wherein said second injector (58) is configured for receiving fluid flows from said lubrication segment (52) and from said cooling segment (56) and for sending said fluid flows to said return duct (53), a sum of said fluid flows coinciding substantially with said first fluid flow.

8. Thermal machine (100) according to any one of the preceding claims, wherein said power unit (1) comprises an outlet shaft (Y) operatively connected to said power transformation organs and configured for receiving said mechanical power and providing in outlet a rotating motion; and / or wherein said thermal machine (100) comprises a power generator (G), for example an alternator, connected with said outlet shaft (Y) in such a way as to receive said rotating motion, preferably at constant angular speed, and generate electric current suitable for supplying an external utility; and / or wherein said power transformation organs are configured for transforming the power of said thermal fluid in said motor circuit (10) in mechanical power according to an operating cycle that provides a sequence of steps of: suction of thermal fluid in said first operating chamber (3A); compression of the thermal fluid in said first operating chamber (3A) and emission of the thermal fluid; loading of thermal fluid in said second operating chamber (3B) and expansion of the thermal fluid in said second operating chamber (3B); unloading of thermal fluid from said second operating chamber (3B); and / or wherein said power unit (1) is a thermal engine comprising a compressor, carrying out said steps of suction and compression, and an expander, for example a turbine, carrying out said steps of loading, expansion and unloading.

9. Thermal machine (100) according to any one of the preceding claims, wherein said thermal fluid in said motor circuit (10) is a mixture comprising a gas and water vapour or water, wherein said gas is preferably air and / or helium and / or other gaseous fluid compatible with the water vapour or the water, and said thermodynamic cycle realized by the thermal machine is a combined thermodynamic cycle.

10. Method for realizing a thermodynamic cycle, the method operating with a thermal fluid and comprising the steps of:- arranging a thermal machine (100) according to one or more of claims from 1 to 9;- carrying out the following steps:- starting said power unit (1), putting in motion said power transformation organs of said thermal fluid;- activating an operating cycle comprising the steps of:- sucking said thermal fluid in said first operating chamber (3A) through said first inlet (4);- compressing said thermal fluid in said first operating chamber (3A) and emitting said thermal fluid from said first outlet (5);- heating the thermal fluid circulating in said second branch (12) of the motor circuit (10) by means of said heater (41);- loading said thermal fluid in said second operating chamber (3B) through said second inlet (6) and expanding said thermal fluid in said second operating chamber (3B);- unloading said thermal fluid from said second operating chamber (3B) through said second outlet (7); wherein said operating cycle steps of sucking, compressing, loading and unloading the thermal fluid determine a transformation of the power of said thermal fluid in mechanical power; said operating cycle comprising also the following steps: sending in said lubrication branch (50) a first fluid flow deriving from said thermal fluid; lubricating said drive shaft (8) by means of at least part of said first flow; feeding said first fluid flow into said second branch (12) at least before the step of loading said thermal fluid into said second operating chamber (3B) through said second inlet (6).

11. Method according to claim 10 and at least claim 3, wherein said first fluid flow comprises at least a part of the liquid component separate by said condensate separator (93); and / or wherein said method comprises also the following steps: sending at least part of the liquid component of the thermal fluid separated by the condensate separator (93) in said vaporization pipeline (20), and sending the remaining part in said supply duct (51) of the lubrication branch (50); letting the liquid component, circulating in the vaporization pipeline (20), through the low temperature side of the vaporizer (95), wherein said liquid component is heated and vaporized before it flows in said second branch (12); introducing said liquid component vaporized in the second branch (12), upstream of the heater (41), through the first injector (97).

12. Method according to claim 10 or 11 and at least claim 6 comprising a step of cooling said casing (2) of the power unit (1) by means of said cooling segment (56); and / or wherein said method comprises a step of distributing the first flow sent in said supply duct (51) between said lubrication segment (52) and said cooling segment (56), said step of distributing being preferably carried out by means of said second diverter valve (57); and / or wherein said method comprises a step of conveying in said return duct (53) the flows distributed on said lubrication segment (52) and said cooling segment (56), said step of conveying being preferably carried out by means of said second injector (58).

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