Energy generation system with an organic rankine cycle and integrated absorption cycle

Description

TECHNICAL FIELD

[0001] The present invention relates to an energy production system combining an organic Rankine cycle and an absorption cycle. The invention will find its application more particularly in an objective of energy recovery and optimization of the electrical production yields of an ORC cycle. STATE OF THE ART

[0002] Thermodynamic cycle electricity generation systems are widely known. In particular, organic Rankine cycles (ORCs) utilize a heat source, commonly a heat source with a temperature between 90°C and 200°C.

[0003] These systems require cooling to condense the steam exiting the expansion device (turbine). This cooling is usually achieved by an air heater or a cooling tower.

[0004] In summer, when the ambient temperature is hot, for example above 35°C, condensation at the turbine outlet will occur at high temperatures, for example up to 60°C, which can lead to a significant loss of electricity production.

[0005] We know of systems which integrate an organic Rankine cycle and an absorption cycle, such as document EP2447483, which provides for a single heat exchanger whose role is to be both the condenser of the Rankine cycle and the evaporator of the absorption cycle, and whose desorber of the absorption cycle is supplied by the Rankine cycle.

[0006] Document CN104236161A also shows an example of a system integrating an organic Rankine cycle and an absorption cycle.

[0007] Document US2016 / 108763 shows a Rankine cycle and an absorption cycle that are connected by an intermediate circuit.

[0008] Although these solutions optimize the cooling of the Rankine cycle, they generate heat rejection by the absorption machine into the ambient air, thus presenting essentially the same problems. There is therefore a need to propose an energy production system with optimized efficiency. SUMMARY

[0009] To achieve this objective, according to one embodiment, an energy production system is provided comprising: - an organic Rankine cycle (ORC) comprising a first circulation loop of a first working fluid comprising a preheating device, a first evaporator, an expander, a first condenser and a first pump, - an absorption cycle comprising a second circulation loop of a working solution comprising an absorber, a generator, a second condenser, a second pump and a second evaporator, characterized in that the system comprises an intermediate circuit capable of receiving an intermediate fluid and ensuring the thermal connection of the ORC cycle and the absorption cycle and on which the second condenser and / or the absorber and the preheating device are arranged.

[0010] The intermediate circuit allows the heat rejection at the outlet of the absorber and condenser components of the absorption cycle to be recovered to preheat the first working fluid of the ORC cycle. This also ensures satisfactory cooling of the absorber and condenser components of the absorption cycle whatever the climatic conditions to enable operation in the best efficiency conditions.

[0011] According to another aspect; the invention relates to a method for producing energy by a system as described above comprising: - the production of electrical energy by the expander of the ORC cycle, - a rejection of heat by the absorber and the second condenser of the absorption cycle, characterized in that the heat rejected by the absorber and / or the second condenser of the absorption cycle is transmitted to the preheating device of the ORC cycle by the intermediate circuit.

[0012] The method thus makes it possible to use the heat discharges from the absorption machine to power the ORC cycle. The invention is defined by the characteristics of the independent claims. BRIEF DESCRIPTION OF THE FIGURES

[0013] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which: The Figure 1 represents the architecture of the energy production system according to one embodiment of the invention.

[0014] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. DETAILED DESCRIPTION

[0015] Before commencing a detailed review of embodiments of the invention, optional features which may optionally be used in combination or alternatively are set out below: According to one example, the intermediate circuit 300 comprises a first intermediate heat exchanger 300 providing heat transfer between the intermediate circuit 300 and a recovery fluid 502. Depending on the operation of the ORC cycle, the recovery of the heat rejection from the absorber and / or condenser components of the absorption cycle to preheat the first working fluid of the ORC cycle may be total or partial, in the latter case, the first intermediate heat exchanger makes it possible to complete the cooling of the intermediate fluid circulating in the intermediate circuit before recovering heat again in the absorber and / or the condenser. According to one example, the recovery fluid 502 comes from an air heater or a cooling tower. Alternatively, the recovery fluid 502 is intended to supply a domestic hot water circuit. According to one example,the second evaporator 205 and the first condenser 106 are thermally connected so that the second evaporator 205 transmits its cold production to the first condenser 106 ensuring the condensation of the first working fluid in the first condenser 106, According to one example, the system comprises a cold source 501 ensuring the thermal connection of the second evaporator 205 of the absorption cycle 200 to the first condenser 106 of the ORC cycle 100, According to one example, the absorption cycle 200 comprises a source to be cooled 500 supplying the second evaporator 205, and a cold source 500 at the outlet of the second evaporator 205 intended to supply the first condenser 106, Alternatively,the first condenser 106 and the second evaporator 205 are shared in a common heat exchanger between the ORC cycle 100 and the absorption cycle 200. This means that the function of first condenser and the function of second evaporator are performed by a heat exchanger common to the ORC cycle and to the absorption cycle, the system comprises a single heat exchanger acting as a condenser of the ORC cycle and as an evaporator of the absorption cycle. According to one example, the ORC cycle 200 comprises a first heat source 400 supplying the first evaporator 104 and in which the absorption cycle 200 comprises a second heat source 405 supplying the generator 203, the first heat source 400 and the second heat source 405 being thermally connected, According to one example,the system comprises a second intermediate heat exchanger 404 configured to ensure the thermal connection of the first heat source 400 and the second heat source 405. Advantageously, the method comprises the thermal transfer of the cold production from the second evaporator 205 of the absorption cycle 200 to the benefit of the first condenser 106 of the ORC cycle 100.

[0016] The process thus allows for optimized integration of the absorption cycle in which the condensation of the first working fluid in the first condenser is optimized by using the cold produced by the absorption cycle. This arrangement is particularly useful for ensuring correct condensation in the first condenser, especially when climatic conditions in summer do not provide a sufficiently low ambient air temperature.

[0017] Upstream and downstream, inlet, outlet, at a given point are taken in reference to the direction of circulation of the fluid.

[0018] "Fluidly connected" or "fluidically connected" means when a line provides a connection through or in which a fluid circulates.

[0019] The expression "A fluidically connected to B" or "A fluidically connected to B" is synonymous with "A is in fluidic connection with B" and does not necessarily mean that there is no organ between A and B. Thus, these expressions are understood to mean a fluidic connection between two elements, this connection may or may not be direct. This means that it is possible that between a first element and a second element which are fluidically connected, a path of a fluid exists through one or more conduits, possibly an additional organ.

[0020] The expressions "arranged on" or "on" are synonyms for "fluidically connected to".

[0021] Conversely, the term "fluidically connected directly" means a direct fluid connection between two elements. This means that between a first element and a second element that are fluidically connected directly, no other element is present, other than a conduit or several conduits.

[0022] By "A is thermally connected to B" or "A is in thermal connection with B" we mean that thermal energy flows between A and B with a fluid connection.

[0023] Hot, cold, cooled, heated means a relative temperature with respect to another point in the system.

[0024] A parameter "substantially equal / greater / less than" or "of the order of" a given value means that this parameter is equal / greater / less than the given value, to within plus or minus 10%, or even plus or minus 5%, of this value.

[0025] The use of the indefinite article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps.

[0026] The terms "first", "second", and "third", etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0027] The system according to the invention comprises an organic Rankine cycle 100 and an absorption cycle 200.

[0028] The system includes an organic Rankine 100 cycle (ORC), also referred to below as the Rankine 100 cycle, which allows mechanical power to be produced from a low or medium temperature heat source. The Rankine 100 cycle allows thermal energy to be recovered by transforming thermal energy into mechanical energy. For example, thermal energy comes from the processing industry (metallurgy, chemicals, paper mills, etc.) with low temperature thermal waste, from transport with a thermal engine where heat is needed: automobiles, boats, or from concentrated solar power, or from biomass or geothermal energy.

[0029] According to one embodiment of the invention, the Rankine cycle 100 comprises an expander 105 and a first pump 107 arranged in series with a first evaporator 104 and a first condenser 106 and advantageously according to the invention a preheating device. The Rankine cycle 100 comprises a first circulation loop 101 intended to receive a working fluid. Advantageously, the first circulation loop 101 ensures the fluidic connection of the constituents of the Rankine cycle 100 so that the working fluid passes through them preferentially successively in the order if after, the preheating device, more precisely the first preheating exchanger 102 then the second preheating exchanger 103, the first evaporator 104, the expander 105, the first condenser 106 and the first pump 107, then again the preheating device. Circulation loop 101 is advantageously a closed circuit.

[0030] The Rankine cycle 100 advantageously comprises a working fluid. The working fluid may be a pure fluid. According to one embodiment, the working fluid is a mixture of fluids, at least two fluids, or even more. The working fluid is preferably organic. The working fluid is for example the fluid R1233 zd.

[0031] According to one aspect of the invention, the Rankine cycle 100 comprises a preheating device. According to one possibility, the preheating device comprises at least a first preheating exchanger 102. Preferably, the preheating device comprises a second preheating exchanger 103. The first preheating exchanger 102 and possibly the second preheating exchanger 103 are heat exchangers arranged on the first circulation loop 101 of the Rankine cycle 100. The preheating device is configured to heat the working fluid up to the vaporization temperature, that is to say, in other words, up to the appearance of the first vapor bubble. The working fluid enters the preheating device in the compressed liquid state and exits at the start of the two-phase state (liquid-vapor).

[0032] Advantageously, the preheating device is fluidically connected to the first pump 107 and to the first evaporator 104. Preferably, the first circulation loop 101 comprises a fluidic connection D arranged between the first pump 107 and the first heat exchanger 102 and allowing the working fluid to enter the first preheating exchanger 102, preferably directly, from the outlet of the first pump 107.

[0033] According to the embodiment illustrated in Figure 1, the first circulation loop 101 comprises a fluid connection E arranged between the first preheating exchanger 102 and the second preheating exchanger 103 and allowing the working fluid to enter the second preheating exchanger 103, preferably directly, from the outlet of the first preheating exchanger 102. According to this embodiment, the first circulation loop 101 comprises a fluid connection F arranged between the second preheating exchanger 103 and the first evaporator 104 and allowing the working fluid to exit the preheating device, preferably directly, towards the first evaporator 104.In the case, not shown, where the preheating device comprises only the first preheating exchanger 102, it is the latter which is in fluid connection with the first evaporator 104 to ensure, preferably directly, the entry of the working fluid into the first evaporator 104, from the outlet of the preheating device.

[0034] Advantageously, according to the invention, the first preheating exchanger 102 is thermally coupled to the intermediate circuit 300 acting as a heat source.

[0035] In the embodiment comprising the second preheating exchanger 103, the latter is thermally coupled to a heat source. According to a preferred possibility, the heat source is preferably the first heat source 400 which may have already passed through the first evaporator 104.

[0036] The Rankine cycle also comprises a first evaporator 104. The first evaporator 104 is a heat exchanger arranged on the first circulation loop 101 of the Rankine cycle 100. The first evaporator 104 is configured to completely evaporate the working fluid. Preferably, the working fluid emerges slightly overheated so as not to send liquid droplets to the expander 105.

[0037] The first evaporator 104 is thermally coupled to a heat source 400. The first evaporator 104 includes a heat source inlet and outlet 400 for supplying heat necessary to superheat the working fluid. For example, the temperature of the heat source 400 is less than 200°C.

[0038] Advantageously, the first evaporator 104 is fluidically connected to the preheating device and to the expander 105. The first circulation loop 101 comprises a fluid connection F arranged between the preheating device, more precisely the second preheating exchanger 103, and the first evaporator 104 allowing the working fluid to enter the first evaporator 104, preferably directly, from the preheating device, more precisely from the outlet of the second preheating exchanger 103. The first circulation loop 101 comprises a fluid connection A arranged between the first evaporator 104 and the expander 105 allowing the working fluid to enter the expander 105, preferably directly, from the outlet of the first evaporator 104.Preferably, the inlet of the first evaporator 104 is fluidically connected to the outlet of the preheating device and the outlet of the first evaporator 104 is fluidically connected to the inlet of the expander 105.

[0039] The Rankine cycle also includes an expander 105 such as, for example, a volumetric expansion machine or a turbine. This expander 105 makes it possible to expand the working fluid and to produce mechanical energy from this expansion. The working fluid enters the expander 105 in the form of high-pressure compressed vapor and leaves the expander 105 in the form of low-pressure expanded vapor. In one embodiment, this energy is recovered on a rotating shaft. This mechanical energy can then be recovered in electrical form at the level of an alternator located on said rotating shaft or a compressor or a pump allowing the use of mechanical energy directly. The expander 105 is for example derived from a conventional volumetric expansion machine from the refrigeration industry; other specific turbomachines or volumetric machines will be more efficient, however.

[0040] The expander 103 is fluidically connected to the first evaporator 104 and to the first condenser 106. The first circulation loop 101 comprises a fluidic connection B arranged between the expander 105 and the first condenser 106, allowing the working fluid to enter the first condenser 106, preferably directly, from the outlet of the expander 105. Preferably, the inlet of the expander 105 is fluidically connected to the outlet of the first evaporator 104 and the outlet of the expander 105 is fluidically connected to the inlet of the first condenser 106.

[0041] The Rankine cycle 100 also includes a first condenser 106. The first condenser 106 is a heat exchanger arranged on the first circulation loop 101 of the Rankine cycle 100. The first condenser 106 is configured to cool the working fluid. The working fluid enters the condenser 106 in the low-pressure expanded vapor state and exits in the liquid state, preferably subcooled to avoid the risk of cavitation in the pump.

[0042] The first condenser 106 is thermally coupled to a cold source 501 for cooling the working fluid to condense it, or even subcool it. During this cooling, the dew point temperature is reached. The cooling is then accompanied by the phenomenon of condensation. The cold source 501 advantageously comes from the absorption cycle described below. The cold source 501 brings the cold produced by the evaporator of the absorption cycle to the first condenser 106 of the Rankin cycle e100.

[0043] Advantageously, the first condenser 106 is fluidically connected to the expander 105 and to the first pump 107. The first circulation loop 101 comprises a fluidic connection C arranged between the first condenser 106 and the first pump 107 allowing the working fluid to enter the first pump 107, preferably directly, from the outlet of the first condenser 106. Preferably, the inlet of the condenser 106 is fluidically connected to the outlet of the expander 105 and the outlet of the first condenser 106 is fluidically connected to the inlet of the first pump 107.

[0044] The Rankine cycle 100 also includes a first pump 107. Preferably, it allows the working fluid to be compressed. The working fluid enters the first pump 107 in a liquid state and exits in a high-pressure compressed liquid state. The first pump 107 requires an input of energy, typically in the form of electricity, to set the working fluid in motion.

[0045] Advantageously, the first pump 107 is fluidically connected to the first condenser 106 and to the preheating device, more preferably to the first preheating exchanger 102. The first circulation loop 101 comprises a fluidic connection D arranged between the first pump 107 and the preheating device and more precisely with the first preheating exchanger 102 allowing the entry of the working fluid into the preheating device, preferably directly, from the outlet of the first pump 107. Preferably, the inlet of the first pump 107 is fluidically connected to the outlet of the first condenser 106 and the outlet of the first pump 107 is fluidically connected to the inlet of the preheating device, more precisely the inlet of the first preheating exchanger 102.

[0046] The first heat source 400 enters the first evaporator 104 to provide energy ensuring the vaporization of the working fluid. According to a preferred embodiment, the first heat source 400 forms at least partially and preferably completely the heat source supplying the second preheating exchanger 103. For example, the heat source 400 enters the first evaporator 104 at a temperature of the order of 200°C and leaves the second preheating exchanger 103 at a temperature of the order of 90°C.

[0047] The system according to the invention also comprises an absorption cycle 200.

[0048] An absorption cycle uses refrigerant / sorbent pairs with strong affinities to replace the vapor compression of traditional heat pump machines. This solution has low electricity consumption, the main energy coming from the thermal source, making it possible to limit the operating cost in the case of the use of a low-cost energy source such as gas for example or free (such as solar energy or heat rejection for example). In addition, the refrigerants used in absorption cycles have no environmental impact: neither on global warming (GWP for Global warning potential = 0) nor on the ozone layer (ODP for Ozone depletion potential = 0).

[0049] The absorption cycle operates using a working solution. This type of absorption cycle operates thanks to the ability of certain liquids to absorb (exothermic reaction) and desorb (endothermic reaction) a vapor. It also takes advantage of the fact that the solubility of this vapor in the liquid depends on temperature and pressure. Thus, an absorption cycle uses as a working solution a binary mixture, one of the components of which is more volatile than the other, and constitutes the refrigerant. For example, the working solution is the NH 3 < / H 2 O pair. The H 2 O / LiBr pair can also be used.

[0050] An absorption cycle 200 comprises four main exchangers (generator 203, absorber 202, condenser 204 and evaporator 205), and advantageously from one to three secondary exchangers. The role of the three secondary exchangers is to improve the performance of the cycle such as: a rectifier, an economizer, a subcooler. According to one possibility, the absorption cycle comprises at least one expansion valve 206, and at least one solution loop comprising a solution pump 208 and an expansion valve 207. This type of cycle operates according to three temperature levels: a low temperature level corresponding to the production of cold at the evaporator 205, an intermediate temperature level corresponding to the condensation temperature of the refrigerant, but also to that of absorption of the refrigerant by the absorbent and a high temperature level corresponding to the driving temperature of the generator 203.

[0051] The absorption cycle 200 comprises a second circulation loop 201 configured to provide fluid connection between the various components of the absorption cycle. The second circulation loop 201 is a closed circuit intended to receive the working solution.

[0052] An absorption cycle operates partly at high pressure between the pump 208 upstream of the generator 203 and the expander 206, downstream of the condenser 204, and partly at low pressure between the expander 206, downstream of the condenser 204 and the pump 208 upstream of the generator 203.

[0053] This thermodynamic cycle is feasible due to the vapor pressure difference between the absorbent and the refrigerant, which varies depending on the temperature and pressure. This variability allows for a concentration difference between the lean solution and the rich solution described below. The advantage of this absorption cycle is that mechanical compression is replaced by thermochemical compression, which uses heat, i.e., a degraded primary energy source. The only primary energy input required is at the solution pump 208, but its work is approximately 96 times less than the work that the vapor compressor must provide for similar operating conditions.

[0054] According to the invention, the absorption cycle comprises a refrigerant / absorbent working solution comprising, according to one possibility, the Ammonia / Water (NH3 / H2O) pair. The concentrations of the working solution and the absorbent in the working solution are adapted to the pressure and temperature of the air treatment and lower than the crystallization concentration of the solution. According to another possibility, the working solution comprises ionic liquids.

[0055] This NH3 / H2O pair can be used for air conditioning applications, but also for refrigeration and there is no possible crystallization over the operating ranges in pressure and temperature. On the other hand, for this pair, the vapor pressure difference between the absorbent and the refrigerant is low. There are therefore traces of water carried with the ammonia vapor at the outlet of the generator 203 sometimes requiring the presence of a rectifier.

[0056] The working solution is said to be rich because the refrigerant concentration is higher than in the so-called lean working solution.

[0057] The absorption cycle 200 of the system according to the invention comprises: a generator 203 configured to vaporize the refrigerant. The generator 203 is fluidly connected to the absorber 202 and to the condenser 204. Advantageously, the generator 203 is fluidly connected to the absorber 202. The absorption cycle comprises a fluid connection K arranged between the generator 203 and the absorber 204 to allow the lean working solution to exit to the absorber 202. Preferably, the absorption cycle 200 comprises an expansion valve 207 arranged on the fluid connection K making it possible to release the pressure of the so-called lean working solution before it is transmitted. The absorption cycle comprises a fluid connection J arranged between the absorber 204 and the generator 203 to allow the rich working solution exiting the absorber 202 to enter the generator 203.Preferably, the absorption cycle 200 comprises a solution pump 208 arranged on the fluid connection J to circulate the working solution in the second circulation loop 201. The fluid connection K and the fluid connection J are part of the solution loop arranged between the generator 203 and the absorber 202. Advantageously, the pump 208 is fluidically connected to an economizer through which the so-called rich working solution is heated before being transmitted to the generator 203. Advantageously, the economizer is an exchanger transmitting heat from the so-called lean solution from the generator 203 to the so-called rich solution from the absorber 202.

[0058] Advantageously, the generator 203 is fluidically connected to the second condenser 204 by a fluidic connection G allowing the refrigerant vapor to exit the generator 203 to the second condenser 204. Advantageously, the generator 203 also comprises an inlet and a second heat source outlet 405 allowing the supply of heat necessary for the vaporization of the refrigerant.

[0059] According to a possibility not shown, the absorption cycle 200 may comprise a rectifier arranged between the generator 203 and the condenser 204, more precisely on the fluid connection G. The rectifier makes it possible to remove by condensation the traces of water carried along with the fluid of the device.

[0060] The absorption cycle of the system according to the invention comprises: a second condenser 204 configured to condense the refrigerant vapor. The condenser 204 is fluidly connected to the generator 203 and to the evaporator 205. Advantageously, the absorption cycle comprises a fluid connection G allowing the refrigerant vapor to enter the condenser 204, preferably directly from the outlet of the generator 203. Advantageously, the condenser 204 is fluidly connected to a second evaporator 205. Preferably, the inlet of the second condenser 204 is fluidly connected to the outlet of the generator 203 and the outlet of the second condenser 204 is fluidly connected to the inlet of the second evaporator 205. The absorption cycle comprises a fluid connection H allowing the refrigerant in the liquid state to exit from the condenser 204, towards the inlet of the second evaporator 205.The absorption cycle may comprise an expansion valve 206 arranged on this fluid connection H and configured to expand the refrigerant fluid in the liquid state coming from the condenser 204. The expansion valve 206 brings the refrigerant fluid to its evaporation pressure.

[0061] Advantageously, the second condenser 204 also comprises a cooling source. The phase change of the refrigerant from the vapor state to the liquid state is accompanied by a release of heat. Advantageously according to the invention, the cooling source of the condenser 204 is formed by the intermediate fluid of the intermediate circuit 300. The release of heat produced by the condenser 204 is transmitted to the intermediate fluid circulating in the intermediate circuit 300.

[0062] Advantageously, the absorption cycle may comprise a subcooler arranged between the condenser 204 and the evaporator 205, and between the evaporator 205 and the absorber 202, more precisely on the fluid connection H and on a fluid connection I at the outlet of the evaporator. The subcooler makes it possible to subcool the refrigerant at the inlet of the evaporator 205 and to preheat the refrigerant to the vapor state at the outlet of the evaporator 205. This exchanger therefore makes it possible to reduce the size of the condenser 204 and the evaporator 205 and thus to significantly improve the performance of the machine. The relevance of this component depends on the operating temperatures, the size of the machine and the cost of the exchangers.

[0063] The absorption cycle of the system according to the invention comprises: a second evaporator 205 configured to vaporize the refrigerant. The evaporator 205 is fluidically connected to the condenser 203 and to the absorber 202. The absorption cycle 200 comprises a fluidic connection I arranged between the outlet of the evaporator 205 and the inlet of the absorber 202 and allowing the refrigerant vapor to exit from the evaporator 205, preferably directly or through a subcooler to the inlet of the absorber 202. Preferably, the inlet of the second evaporator 205 is fluidically connected to the outlet of the second condenser 204 and the outlet of the second evaporator 205 is fluidically connected to the inlet of the absorber 202. Advantageously, the evaporator 205 also comprises an inlet and an outlet of a second source to be cooled 500. The phase change of the refrigerant from the liquid state to the vapor state is accompanied by a heat transmission from the source to be cooled 500 to the refrigerant.The source to be cooled 500 transmits calories and thus sees its temperature lower. The evaporator 205 is the place where frigories are produced.

[0064] The absorption cycle of the system according to the invention comprises: an absorber 202 configured to condense the refrigerant vapor from the evaporator 205. The absorber 202 is fluidly connected to the evaporator 205 and to the generator 203. Advantageously, the absorber 202 is fluidly connected to the evaporator 205, more precisely to the subcooler, by the fluid connection I allowing the entry of the refrigerant in the vapor state into the absorber 202. Advantageously, the absorber 202 and the generator 203 are fluidly connected by the solution loop. The phase change of the refrigerant from the vapor state to the liquid state is accompanied by a release of heat which is transmitted to a cooling source. Advantageously according to the invention, the cooling source of the absorber 202 is formed by the intermediate circuit 300 and more precisely by the circulating intermediate fluid.The heat produced by the absorber 202 is evacuated to the benefit of the intermediate circuit 300, more precisely to the benefit of the intermediate fluid circulating in said circuit 300.

[0065] According to one aspect of the invention, the system comprises an intermediate circuit 300 capable of receiving an intermediate fluid. The intermediate circuit 300 is a fluid circulation loop, preferably in a closed circuit. The intermediate circuit 300 is configured to ensure the thermal connection between the ORC cycle 100 and the absorption cycle 200. The intermediate circuit 300 is intended to supply the ORC cycle 100 with heat rejected by the absorption cycle 200. The heat rejected by the absorption cycle 200 by the absorber 202 and / or the condenser 204 is transmitted to the ORC cycle 100 by the intermediate circuit 300. The heat is advantageously transmitted to the preheating device of the ORC cycle 100 and in particular to the first preheating exchanger 102.The intermediate circuit 300 ensures the fluid circulation of the intermediate fluid successively in the absorber 202 and / or the condenser 204 and in the preheating device, more precisely in the first preheating exchanger 102.

[0066] Preferably, the absorber 202 and the condenser 204 are arranged on the intermediate circuit 300 successively, that is to say in series, so that the intermediate fluid circulates in the absorber 202 to recover the heat rejected by the latter and then circulates in the condenser 204 in which the intermediate fluid also recovers the heat rejected by the latter.

[0067] According to a possibility not shown, the intermediate circuit may comprise the condenser 204 and the absorber 202 arranged in parallel. Thus, there is a recovery of the heat rejected by the absorber and the condenser independently, making it possible to choose to recover one or the other or both.

[0068] According to a possibility not shown, the intermediate circuit 300 comprises bypasses configured to allow the circulation of the intermediate fluid without circulating in the absorber 202 or the condenser 204. The intermediate circuit comprises the circulation in the absorber 202 or in its first bypass depending on whether the heat from the absorber must be recovered or not depending on the needs and temperatures of predefined points of the system, then the circulation in the condenser 204 or in its second bypass depending on whether the heat from the absorber must be recovered or not depending on the needs and temperatures of predefined points of the system.

[0069] According to the embodiment illustrated, by way of example, the intermediate fluid enters the absorber 202 at a temperature of the order of 35°C and leaves it at a temperature of the order of 58°C. Preferably, the intermediate fluid enters the condenser 204 at this temperature and leaves it at a temperature of the order of 75°C. The intermediate fluid circulates in the preheating device of the ORC cycle 100, in particular in the first preheating exchanger 102. Depending on the needs of the ORC cycle, the intermediate fluid transmits more or less heat to the ORC cycle 100.

[0070] According to a preferred embodiment, the intermediate circuit 300 comprises a first intermediate exchanger 301 arranged on the intermediate circuit 300 between the ORC cycle 100 and the absorption cycle 200, i.e. between the preheating device and the absorber 202 or the condenser 204, if the absorber 202 is not arranged on the intermediate circuit 300. The first intermediate exchanger 301 is arranged downstream of the preheating device and more precisely of the first preheating exchanger 102. The first intermediate exchanger 301 is arranged upstream of the absorber 202, or of the condenser 204 if the absorber 2022 is not arranged on the intermediate circuit 300. The first intermediate exchanger 301 makes it possible to use the residual heat of the intermediate fluid at the outlet of the preheating device. Thus, if the recovery of thermal energy by the ORC cycle 100 is only partial then the first intermediate exchanger 301 finishes this thermal recovery.For example, a recovery fluid circulates in the first intermediate exchanger 301. The recovery fluid may be a cooling source such as an air flow from a cooling tower or an air heater. According to one possibility, the recovery fluid is intended to supply a domestic hot water network. This arrangement makes it possible both to use all of the thermal energy rejected by the absorption cycle 200 and to ensure that the intermediate fluid can once again play its function as a cold source with the absorber 202 and / or the condenser 204.

[0071] For example, the intermediate fluid is chosen from water or oil.

[0072] The intermediate circuit 300 comprises a fluid connection L arranged between the condenser 204 and the preheating device, more precisely the first preheating exchanger 102 to ensure the circulation of the intermediate fluid between the outlet of the condenser 204, preferably directly, to the inlet of the preheating device, more precisely the first preheating exchanger 102. The intermediate circuit 300 comprises a fluid connection M arranged between the preheating device, more precisely the first preheating exchanger 102 and advantageously the first intermediate exchanger 301 to ensure the circulation of the intermediate fluid between the outlet of the preheating device, more precisely the first preheating exchanger 102, to, preferably directly, the inlet of the first intermediate exchanger 301.The intermediate circuit 300 comprises a fluid connection N arranged between the first intermediate exchanger 301 and the absorber 202 to ensure the circulation of the intermediate fluid from the outlet of the first intermediate exchanger 301 to, preferably directly, the inlet of the absorber 202. The intermediate circuit comprises a fluid connection O arranged between the absorber 202 and the condenser 204 to ensure the circulation of the intermediate fluid from the outlet of the absorber 200 to, preferably directly, the inlet of the condenser 204.

[0073] According to one aspect of the invention, the system comprises an additional thermal connection between the ORC cycle 100 and the absorption cycle 200. This additional thermal connection is in addition to the thermal connection provided by the intermediate circuit 300. Advantageously, the system comprises a thermal connection between the second evaporator 205 of the absorption cycle 200 and the first condenser 106 of the ORC cycle 100. The thermal connection is advantageously provided by a cold source 501 from the second evaporator 205 of the absorption cycle 200 to the first condenser 106 of the ORC cycle. This arrangement is particularly useful for ensuring a cold source temperature 501 at the first condenser 106 that is sufficiently low regardless of the climatic conditions. Indeed, the condenser 106 of the ORC cycle requires cooling to condense the vapor leaving the expander 105.In particular, when the environment is hot, for example above 35°C, condensation will take place at high temperatures, for example up to 60°C, which can lead to a significant loss of electricity production. The absorption cycle 200 therefore provides additional cooling through thermal coupling. The second evaporator 205 of the absorption cycle 200 is used to cool the cold source 501 of the first condenser 106 of the ORC cycle 100. A source to be cooled 500 circulates beforehand in the second evaporator 205 to ensure the evaporation of the working solution of the absorption cycle 200. The heat source 500 transfers thermal energy to the absorption cycle 200 and emerges cooled from the second evaporator 205 in the form of a cold source 501. The cold source 501 supplies the first condenser 106 to allow optimal condensation of the working fluid.

[0074] Advantageously, the system comprises a fluid connection P arranged to penetrate into the second evaporator 205 and ensure the entry of the first source to be cooled 500 into the second evaporator 205. Advantageously, the system comprises a fluid connection Q arranged between the second evaporator 205 and the first condenser 106 to ensure the circulation of the cold source 501 from the outlet of the evaporator 205, preferably directly, to the inlet of the condenser 106. Advantageously, the system comprises a fluid connection R ensuring the exit of the cold source 501 from the condenser 106.

[0075] According to one possibility, the condenser 106 may comprise an additional cold source.

[0076] According to one possibility, the source to be cooled 500 comes from a cooling circuit conventionally used for cooling an ORC cycle. The source to be cooled 500 is chosen from an air flow coming from an air heater or a cooling tower.

[0077] According to one possibility, the source to be cooled 500 and the recovery fluid 502 come from the same cooling circuit supplied by an air heater or a cooling tower.

[0078] For example, the source to be cooled 500 enters the second evaporator 205 at a temperature of the order of 25°C. The source to be cooled 500 exits in the form of a cold source 501 at a temperature of the order of 20°C to enter the first condenser 106. The cold source 501 exits the condenser 106 at a temperature of the order of 50°C.

[0079] According to another aspect; the invention comprises an additional thermal connection between the ORC cycle and the absorption cycle 200. The additional thermal connection is intended to ensure the thermal connection between the generator 203 of the absorption cycle 200 and at least the second evaporator 104 of the ORC cycle 100. The additional thermal connection is configured to use as the second heat source 405 of the generator 203 of the absorption cycle 200, the first heat source 400 supplying the first evaporator 104 of the ORC cycle 100. Thus, the addition of the absorption cycle 200 to the ORC cycle 100 does not require having a new heat source to supply said absorption cycle 200. The first heat source 400 supplying the first evaporator 104 may come from renewable energy such as geothermal energy, solar energy, fatal energy such as residual thermal energy from industrial processes, or even fossil energy.For example, the first heat source 400 enters the first evaporator 104 at a temperature of between 90° and 200°C. The heat source 400 exits the first evaporator 104 and possibly passes through the preheating device and more precisely the second preheating exchanger 103. The heat source 400 exits for example at a temperature of the order of 90°C. The system according to the invention advantageously comprises at least one tapping 401, 402, 403 ensuring the diversion of a part of the first heat source 400 for the benefit of the generator 203. The system advantageously comprises a control module ensuring the operation of the at least one tapping 401, 402, 403 as a function of the temperatures of the heat source 400 and the needs of the generator 203. Preferably, the system comprises three tappings 401, 402, 403.The system advantageously comprises a first tapping 401 arranged upstream of the inlet of the first hot source 400 in the first evaporator 104. The system advantageously comprises a second tapping 402 arranged downstream of the outlet of the first hot source 400 of the first evaporator 104 and upstream of the heating device, more precisely of the second preheating exchanger 103. The system advantageously comprises a third tapping 402 arranged downstream of the outlet of the hot source of the second preheating exchanger 103.

[0080] According to a first possibility, the first hot source 400 from one of the tappings 401, 402, 403 circulates directly in the generator 203, the first hot source 400 and the second hot source 405 are identical. According to another possibility, the system comprises a second intermediate exchanger 404 ensuring the heat transfer from the first hot source 400 to a second hot source 405. The second hot source 405 circulates in a closed circuit between the second intermediate exchanger 404 and the generator 203.

[0081] The invention is not limited to the embodiments previously described and extends to all embodiments covered by the invention. LIST OF REFERENCES

[0082] 100. Organic Rankine Cycle 101. First Circulation Loop 102. First Preheat Exchanger 103. Second Preheat Exchanger 104. First Evaporator 105. Expander 106. First Condenser 107. First Pump 200. Absorption Cycle 201. Second Circulation Loop 202. Absorber 203. Generator 204. Second Condenser 205. Second Evaporator 206. Expansion Valve 207. Expansion Valve 208. Solution Pump 300. Intermediate Circuit 301. First Intermediate Exchanger 400. First Heat Source of the Organic Rankine Cycle 401. First Tap 402. Second Tap 403. Third Tap 404. Second Intermediate Exchanger 405. Second Heat Source of the Absorption Cycle 500. Source to be Cooled of the Cycle absorption 501. Cold source of the organic Rankine cycle 502. Recovery fluid A. Fluid connection between the evaporator outlet and the expander inlet B.Fluid connection between the expander outlet and the condenser inlet C. Fluid connection between the condenser outlet and the first pump inlet D. Fluid connection between the first pump outlet and the first heater inlet E. Fluid connection between the first heater outlet and the second heater inlet F. Fluid connection between the second heater outlet and the first evaporator inlet G. Fluid connection between the generator outlet and the second condenser inlet H. Fluid connection between the second condenser outlet and the second evaporator inlet I. Fluid connection between the second evaporator outlet and the absorber inlet J. Fluid connection between the absorber outlet and the generator inlet K. Fluid connection between the generator outlet and the absorber inlet L. Fluid connection between the second condenser outlet and the first heater inlet M.Fluid connection between the outlet of the first heater and the inlet of the first exchanger N. Fluid connection between the outlet of the first exchanger and the inlet of the absorber O. Fluid connection between the outlet of the absorber and the inlet of the second condenser P. Fluid connection of the inlet of the cold source in the second evaporator Q. Fluid connection between the outlet of the second evaporator and the inlet of the first condenser.

Claims

1. System for producing energy, comprising: - An organic Rankine cycle (100) (ORC) comprising a first circulation loop (101) of a first working fluid comprising a preheating device, a first evaporator (104), an expander (105), a first condenser (106) and a first pump (107), - An absorption cycle (200) comprising a second circulation loop (201) of a working solution comprising an absorber (202), a generator (203), a second condenser (204), a second pump (208) and a second evaporator (205), characterised in that the system comprises an intermediate circuit (300) capable of receiving an intermediate fluid and ensuring the thermal connection of the ORC cycle (100) and of the absorption cycle (200), and on which the second condenser (204), the absorber (202) and the preheating device are arranged.

2. System according to the preceding claim, wherein the intermediate circuit (300) comprises a first intermediate heat exchanger (301) ensuring a heat transfer between the intermediate circuit (300) and a recovery fluid (502).

3. System according to the preceding claim, wherein the recovery fluid (502) comes from an air heater or from a cooling tower.

4. System according to claim 2, wherein the recovery fluid (502) is intended to supply a circuit with sanitary hot water.

5. System according to any one of the preceding claims, wherein the second evaporator (205) and the first condenser (106) are thermally connected, such that the second evaporator (205) transmits its cold production to the first condenser (106) ensuring the condensation of the first working fluid in the first condenser (106).

6. System according to the preceding claim, wherein the system comprises a cold source (501) ensuring the thermal connection of the second evaporator (205) of the absorption cycle (200) to the first condenser (106) of the ORC cycle (100).

7. System according to any one of the two preceding claims, wherein the absorption cycle (200) comprises a source to cool (500) supplying the second evaporator (205), and a cold source (501) at the outlet of the second evaporator (205) intended to supply the first condenser (106).

8. System according to any one of claims 1 to 5, wherein the first condenser (106) and the second evaporator (205) are pooled in a common heat exchanger between the ORC cycle (100) and the absorption cycle (200).

9. System according to any one of the preceding claims, wherein the ORC cycle (200) comprises a first heat source (400) supplying the first evaporator (104), and wherein the absorption cycle (200) comprises a second heat source (405) supplying the generator (203), the first heat source (400) and the second heat source (405) being thermally connected.

10. System according to the preceding claim, comprising a second intermediate heat exchanger (404) configured to ensure the thermal connection of the first heat source (400) and the second heat source (405).

11. Method for producing energy by a system according to any one of the preceding claims, comprising: - the production of electrical energy by the expander (105) of the ORC cycle (100), - a rejection of heat by the absorber (202) and the second condenser (204) of the absorption cycle (100), characterised in that the heat rejected by the absorber (202) and the second condenser (204) of the absorption cycle (200) is transmitted to the preheating device of the ORC cycle (100) by the intermediate circuit (300).

12. Method according to the preceding claim, comprising the heat transfer of the cold production of the second evaporator (205) of the absorption cycle (200) in favour of the first condenser (106) of the ORC cycle (100).