OPEN-LOOP COGENERATION PROCESS

Description

[0001] The present invention relates to the field of energy cogeneration.

[0002] In this field, it is common to combine the production of electrical energy and the production of thermal energy using systems comprising a turbine, a heat source creating fumes and an exchanger between the fumes and the turbine, for example a boiler.

[0003] There are various cogeneration solutions, all based on this principle.

[0004] Temperature and energy values ​​vary depending on needs and systems, however, known open cycle systems generally have an overall efficiency of less than 80%, which is not satisfactory.

[0005] For example, document D1 (CN 204082237) is known, which proposes a solution that requires at least one compressor.

[0006] The present invention aims to solve this problem by proposing a solution which, thanks to a clever arrangement of exchangers and possibly other means of energy recovery, described later, achieves an efficiency of approximately 98%. SUMMARY OF THE INVENTION

[0007] More specifically, the invention relates to an open cycle cogeneration system for thermal and electrical energy, comprising: a set of at least one heat exchanger, configured to be connected to combustion fumes from a hearth; said set of at least one heat exchanger comprising a process air inlet and outlet, a turbine, configured to produce electrical energy, connected to the process air outlet of said set of at least one heat exchanger, a process air outlet line, connecting the turbine outlet to the outside, a combustion fumes outlet line, for evacuating the combustion fumes to the outside, a set of at least one compressor, configured to compress the process air at the inlet of the set of at least one heat exchanger.

[0008] It is essentially characterized in that it further comprises, an absorption heat pump, comprising: * a hot fluid circuit, * a cold fluid circuit, * a warm fluid circuit, or useful network, and * a set of at least one exchanger for exchanging heat between at least one of the circuits of the heat pump and at least one of the treatment air outlet line and the combustion fumes outlet line.

[0009] It is also possible to provide a set of at least one thermoelectric device, making it possible to produce electricity from a heat source of more than 150°C and arranged on at least one of the treatment air outlet line and the combustion fumes outlet line.

[0010] The thermoelectric device can be expected to be at least one of: an organic Rankine cycle machine; an expander, especially a screw expander; a steam turbine.

[0011] It can be provided that the system further comprises a set of at least one exchanger for exchanging heat between at least one of: the hot fluid circuit and the process air outlet line, the hot fluid circuit and the combustion fumes outlet line, the warm fluid circuit and the process air outlet line, the warm fluid circuit and the combustion fumes outlet line, the cold fluid circuit and the process air outlet line, and the cold fluid circuit and the combustion fumes outlet line.

[0012] It is also possible to provide an enclosure, configured to produce thermal energy and combustion fumes, and comprising said hearth and a combustion fume outlet; said assembly of at least one heat exchanger may be internal or external to the enclosure.

[0013] The enclosure can be predicted to be one of: a boiler, an industrial furnace, an incinerator.

[0014] It is possible to provide that the hearth comprises combustion air, said combustion air being outside air which is treated in a circuit for combustion air, said circuit for combustion air comprising at least one of: a set of at least one exchanger for exchanging heat with the treatment air outlet line, and a set of at least one exchanger for exchanging heat with the combustion fumes outlet line.

[0015] A heat exchanger may be provided, arranged upstream of the enclosure, and configured to preheat the treatment air at the inlet of the enclosure or at the inlet of the assembly of at least one heat exchanger connected to the combustion fumes coming from the hearth, and with the heat of the treatment air at the outlet of the turbine.

[0016] It can be expected that the useful network will have, at the inlet of the absorption heat pump, a temperature between 35°C and 65°C, and at the outlet of the absorption heat pump, a temperature between 40°C and 90°C.

[0017] The useful network can be considered an urban heat network, or an industrial process network that uses heat. Or any other thermal process network that uses heat.

[0018] It can be expected that the thermoelectric device is equipped with an internal exchanger, configured to exchange thermal energy with the useful network.

[0019] Other characteristics and advantages of the present invention will appear more clearly on reading the following description given by way of illustrative and non-limiting example and made with reference to the appended figures. DESCRIPTION OF THE DRAWINGS

[0020] [ Fig. 1] illustrates a diagram of an embodiment of the system according to the invention. DETAILED DESCRIPTION

[0021] The solution according to the invention comprises a set of means, described below, which include in particular: a circuit for treatment air AT, a circuit for combustion air _AC, for the hearth of the enclosure described later, a circuit for combustion fumes FC, of ​​said enclosure.

[0022] By conciseness, we mean indistinctly "the enclosure" and "the hearth of the enclosure".

[0023] The invention cleverly uses the energy of at least one circuit among: the treatment air circuit, the combustion air circuit and the combustion fumes circuit, thanks to a set of heat exchangers.

[0024] For brevity, heat exchangers are referred to as "exchangers."

[0025] Similarly, by conciseness, "an exchanger" or "the exchanger" means a set of at least one exchanger. Also, the "first", "second", "third", etc. exchanger is to be understood as a first set of at least one exchanger, a second set of at least one exchanger, a third set of at least one exchanger, etc.

[0026] Each circuit is separate, so that the treatment air passes through a set of pipes separate from the set of pipes through which the combustion air of the enclosure passes, and separate from the set of pipes through which the combustion fumes pass.

[0027] For brevity, no pipelines are described here.

[0028] The numerical values ​​presented here are from a simulation. They are consistent with each other, illustrative, but not exhaustive. These values ​​are given with a deviation of plus or minus 10%. * Process air circuit *

[0029] The treatment air comes from any air source, in this case the outside air EXT, ambient, which is treated as described below.

[0030] The present invention is based on a cogeneration system comprising a cycle known as the “hot air cycle”.

[0031] The hot air cycle comprises an enclosure and a turbine, a network of treatment air pipes, a network of combustion air pipes for the enclosure, a network of combustion fumes pipes for the enclosure and a set of exchangers described later.

[0032] In the hot air cycle, the process air is taken from outside and brought to the inlet of the enclosure through at least one compression stage, and in this case two compression stages.

[0033] A first compression stage is provided, comprising a first compressor 10, in which process air is taken from outside and compressed by the first compressor.

[0034] For example, the outside air is at a temperature of 10°C. It is compressed to a predetermined threshold value, in this case 4.2 Bars. Preferably, the threshold value is greater than or equal to 3 Bars. At the outlet of the first compressor, the process air is at 183°C.

[0035] A second compression stage can then be provided, comprising a second compressor 20, to compress the treatment air downstream of the first compressor. The treatment air is thus maintained at 183°C and at the threshold pressure, in this case 4.2 Bars.

[0036] Between the first compressor and the second compressor, advantageously mounted in series, at least one first exchanger for the combustion air 1_AC, described later, can be arranged.

[0037] All the elements described above: first and second compressor, flanges for the heat exchanger, etc. can be included in a module in the form of a unitary box. It is even possible to provide for them to be integrated into a unitary box with the hot air turbine which drives the compressors directly from its mechanical shaft. - Pregnant -

[0038] The enclosure 100 is for example a boiler, in this case a biomass boiler, and more particularly a wood boiler. Preferably, the enclosure comprises an external heat exchanger (not shown).

[0039] The process air compressed by the compressors is then heated by the enclosure, in this case to 703°C, with a flue gas temperature of 900°C in the enclosure. The actual input power of the enclosure is 2579 kW and the power exchanged by the enclosure is 1438 kW.

[0040] The process air heated by the enclosure is then expanded, in this case in a hot air turbine 200. The process air is therefore brought directly from the enclosure outlet to the turbine inlet.

[0041] It is also possible to envisage that the enclosure is an industrial furnace or an incinerator. In this case, it is possible to envisage connecting a heat exchanger directly to the waste heat fumes from the industrial furnace or the incinerator. Preferably, the waste heat fumes are at more than 600°C. In this case, a set of at least one exchanger between the waste heat fumes and the process air is suitable.

[0042] The turbine can be used to recover electrical energy, in this case 1150 kW of real power. If the turbine and compressor(s) are integrated into a single module, 330 kWe net is recovered due to the driving force to drive the compressor.

[0043] At the turbine outlet, the expanded air has a temperature of 494°C and a pressure of 1.05 Bar.

[0044] This heat can be advantageously used to preheat the compressed process air at the inlet of the enclosure or of the assembly of at least one heat exchanger, thanks to a first heat exchanger for the process air 1_AT arranged between the outlet of the second compressor and the inlet of the enclosure or of the assembly of at least one heat exchanger. The first heat exchanger for the process air 1_AT makes it possible to increase the temperature of the process air from 183°C to 448°C at the inlet of the enclosure, and to lower the temperature of the process air at the outlet of the turbine from 495°C to 235°C, equivalent to an exchanged power of 1347 kW.

[0045] Thanks to the preheating of the treatment air, the enclosure is more efficient and consumes less biomass energy.

[0046] At the outlet of the hot air cycle, i.e. at the outlet of the first heat exchanger for the process air 1_AT, the temperature of the expanded process air is 235°C.

[0047] This heat can then be advantageously used by a set of heat exchangers arranged along a process air outlet line, which connects the turbine outlet to the outside.

[0048] The set of heat exchangers arranged along the treatment air line can in fact be used to exchange thermal energy with at least one of: the combustion air entering the enclosure, the heat transfer fluid of a hot fluid circuit described later, the heat transfer fluid of a cold fluid circuit described later, the heat transfer fluid of a warm fluid circuit, or useful network, described later, and the internal heat transfer fluid of a thermoelectric device, described later.

[0049] All of these exchangers are described later.

[0050] At the end of the process air outlet line, the process air is at 25°C and can be released into the atmosphere. * Combustion smoke circuit *

[0051] The combustion fumes leaving the enclosure have a high temperature, in this case 645°C.

[0052] This heat is advantageously used by a set of exchangers arranged along a combustion fume outlet line, which connects the enclosure outlet to the outside, and which are described later.

[0053] The set of heat exchangers arranged along the combustion flue gas outlet line can be used to exchange thermal energy with at least one of: the combustion air entering the enclosure, the treatment air entering the enclosure, the heat transfer fluid of the hot fluid circuit described later, the heat transfer fluid of the cold fluid circuit described later, the heat transfer fluid of the useful network described later, the internal heat transfer fluid of a thermoelectric device, described later. * Heat pump *

[0054] A 300 heat pump is planned.

[0055] In this case, we are planning a 300 absorption heat pump, or PACA, known in itself.

[0056] PACA includes: a hot fluid circuit, in this case superheated water; a cold fluid circuit, in this case cold water, and a medium temperature fluid circuit, or useful network, in this case lukewarm water.

[0057] The fluid is a heat transfer fluid, for example, water. Cold water is cooling water. The terms "cold," "warm," and "hot" are relative. They mean that the temperature of cold water is lower than the temperature of warm water, which is itself lower than the temperature of hot water.

[0058] The PACA inlet and outlet temperature values ​​for each fluid circuit are predetermined setpoint values. They may differ from the simulation values ​​given here.

[0059] The 3 fluid circuits above are configured to recover heat, using exchangers, on at least one line among: the process air outlet line, the combustion fumes outlet line, and the combustion air circuit.

[0060] Advantageously, a double heat recovery is implemented, in this case on the treatment air outlet line and on the combustion fumes outlet line, which increases the efficiency of the process; and which makes it possible to lower the temperature of the combustion fumes to a value of 42°C at the end of the combustion fumes outlet line, and to lower the temperature of the treatment air to a value of 32°C at the end of the treatment air outlet line, i.e. almost ambient temperatures.

[0061] By constructing a PACA, the temperature of the warm fluid circuit, at the inlet and outlet of the PACA, is a function of the temperature of the hot fluid circuit, at the inlet and outlet of the PACA and of the temperature of the cold fluid circuit, at the inlet and outlet of the PACA.

[0062] In this case: for the hot fluid circuit, the temperature of the heat transfer fluid at the inlet of the PACA is 170°C, and the temperature at the outlet of the PACA is 95°C; for the cold fluid circuit, the temperature of the heat transfer fluid at the inlet of the PACA is 35°C, and the temperature at the outlet of the PACA is 28°C; for the warm fluid circuit, the temperature of the heat transfer fluid at the inlet of the PACA is 60°C, and the temperature at the outlet of the PACA is 80°C. - Hot fluid circuit -

[0063] In this case, the heat transfer fluid in the hot fluid circuit is superheated water, at a pressure of 12 bars to prevent it from turning into steam. However, the superheated water can also be replaced by water vapor. In this case, the temperature of the heat transfer fluid at the PACA inlet can be 150°C.

[0064] It is possible to provide for a first exchanger of the hot fluid circuit 1_FC, in this case superheated water, on the treatment air outlet line, more particularly downstream of the third exchanger for the combustion air described later.

[0065] Thanks to the third exchanger for the combustion air, the combustion air goes from a temperature of 30°C to a temperature of 195°C, and the treatment air goes from a temperature of 235°C to a temperature of 178°C, equivalent to an exchanged power of 275 kW.

[0066] Thanks to the first exchanger of the hot fluid circuit, the treatment air goes from a temperature of 178°C to a temperature of 103°C, and the temperature of the heat transfer fluid of the hot fluid circuit goes from 95°C to 170°C.

[0067] A second exchanger for the hot fluid circuit 2_FC can also be provided, arranged along the combustion fumes outlet line, in this case between the fourth combustion air exchanger and the second exchanger for the warm fluid circuit.

[0068] Thanks to this second exchanger, the temperature of the combustion fumes drops from 244°C to 110°C, and the superheated water leaving the heat pump drops from 95°C to 170°C.

[0069] A T is therefore provided on an outlet pipe of the hot fluid circuit of the heat pump and a T on an inlet pipe of the hot fluid circuit of the heat pump, making it possible to distribute the superheated water to the first and second exchangers of the hot fluid circuit, and to collect the superheated water from the first and second exchangers of the hot fluid circuit, respectively.

[0070] Thanks to the first exchanger of the hot fluid circuit and the second exchanger of the hot fluid circuit, the superheated water of the heat pump goes from a temperature of 95°C at the outlet of the latter to 170°C at the inlet of the latter, after heat exchanges with the treatment air and the combustion fumes.

[0071] Alternatively, or in combination, it is also possible to provide a set of at least one exchanger between the hot fluid circuit and the combustion air circuit.

[0072] The PACA also includes a cold water inlet and outlet circuit, i.e. a cold fluid circuit. - Cold fluid circuit -

[0073] In a similar manner to the hot fluid circuit, it is possible to provide a first exchanger of the cold fluid circuit 1_FF on the treatment air outlet line, more particularly downstream of the exchanger of a useful network, or useful heat network RCU, described below.

[0074] Thanks to the first exchanger of the cold fluid circuit, the treatment air goes from a temperature of 69°C to a temperature of 32°C, and the heat transfer fluid of the cold water circuit goes from a temperature of 28°C to a temperature of 35°C, equivalent to an exchanged power of 168 kW.

[0075] A second exchanger for the cold fluid circuit 2_FF, of the condenser type or not, can also be provided, arranged along the combustion flue gas outlet line, which allows the cold water leaving the heat pump to be heated. In this case, the second cold water exchanger is last on the combustion flue gas outlet line, before releasing the flue gas into the atmosphere.

[0076] Thanks to this second exchanger in the cold fluid circuit, the temperature of the combustion fumes drops from 84°C to 42°C, and the cold water drops from a temperature of 28°C to a temperature of 35°C, equivalent to an exchanged power of 260 kW.

[0077] A T is therefore provided on an outlet pipe of the heat pump and a T on an inlet pipe of the heat pump, of the cold fluid circuit, allowing the cold water to be distributed to the first and second exchanger of the cold fluid circuit, and the cold water to be collected from the first and second exchanger of the cold fluid circuit. - Warm fluid circuit -

[0078] Similar to the hot and cold fluid circuits, the PACA also includes an inlet and outlet circuit for medium temperature, or lukewarm, water, with an inlet temperature of 60°C and an outlet temperature of 80°C, which are in this case predetermined setpoint values ​​for an urban heating network. The values ​​given in this description optimize the process implemented in the simulation, and are calculated from these two setpoint values.

[0079] This heat can be used for any purpose, industrial, urban heat network or other, which is why the warm fluid circuit is also called a “useful network”.

[0080] For this purpose, it is possible to provide a first exchanger of the warm fluid circuit 1_FT on the treatment air outlet line, more particularly downstream of the first exchanger of the hot fluid circuit 1_FC, and upstream of the first exchanger of the cold fluid circuit 1_FF.

[0081] Thanks to the first exchanger of the warm fluid circuit, the treatment air goes from a temperature of 103°C to a temperature of 69°C, and the heat transfer fluid of the warm water circuit goes from 60°C to 80°C, equivalent to an exchanged power of 160 KW.

[0082] Preferably, the first exchanger of the warm fluid circuit is arranged upstream of the first exchanger of the cold fluid circuit, and downstream of the first exchanger of the hot fluid circuit.

[0083] A second exchanger for the 2_FT warm fluid circuit can also be provided, arranged along the combustion fumes outlet line.

[0084] Preferably, the second exchanger of the warm water circuit is arranged upstream of the second exchanger of the cold fluid circuit, and downstream of the second exchanger of the hot fluid circuit.

[0085] The second exchanger in the warm water circuit allows the flue gas temperature to be lowered from 110°C to 84°C, and the heat transfer fluid in the warm water circuit to be heated from 60°C to 80°C, equivalent to an exchanged power of 51 KW.

[0086] For the PACA, we therefore have three exchangers per line: one exchanger for the hot fluid circuit, one exchanger for the warm water circuit and one exchanger for the cold fluid circuit on the combustion fumes line, and the same on the treatment air line.

[0087] Alternatively, or in combination, it is also possible to provide a set of at least one exchanger on the combustion air circuit for at least one of the circuits among: The hot fluid circuit, the warm water circuit, and the cold fluid circuit.

[0088] In cumulative values ​​across all PACA exchangers, we have an exchanged power equal to 1057 kW. * Circuit for combustion air *

[0089] The combustion air is in this case outside air which is treated by a set of at least one exchanger and brought to the entrance of the enclosure.

[0090] We can therefore provide a set of exchangers on the combustion air circuit which allow, as previously, to advantageously implement a double heat recovery: with the treatment air outlet line and with the combustion fumes outlet line. - On the treatment air line -

[0091] A first exchanger for the combustion air can be provided, placed on the treatment air line, in this case upstream of the second compressor.

[0092] The first exchanger for combustion air increases the temperature of the combustion air upstream of the enclosure.

[0093] A second exchanger for the combustion air 2_AC can be provided, arranged on the treatment air line, in this case at the end of the treatment air line, downstream of the first cold water exchanger, and at the outlet of which the treatment air is released into the atmosphere.

[0094] The second exchanger for the combustion air makes it possible to lower the temperature of the treatment air, in this case from 32°C to 25°C; and makes it possible to increase the temperature of the combustion air, which in this case is ambient air, from 10°C to 30°C, equivalent to an exchanged power of 33 kW.

[0095] A third exchanger for the combustion air 3_AC can be provided, arranged on the treatment air line, in this case upstream of the first superheated water exchanger 1_FC.

[0096] The third exchanger for the combustion air makes it possible to increase the temperature of the combustion air, in this case from 30°C to 195°C, and to lower the temperature of the treatment air, in this case from 235°C to a temperature of 178°C, equivalent to an exchanged power of 275 kW. - On the combustion fumes line -

[0097] A fourth exchanger for the combustion air 4_AC can be provided, arranged on the combustion fumes line, in this case between the thermoelectric device 400 described later and the second exchanger for the hot fluid circuit 2_FC.

[0098] The fourth exchanger for combustion air increases the temperature of the heat transfer fluid and reduces the temperature of the combustion fumes.

[0099] A fifth exchanger for the combustion air 5_AC can be provided, arranged on the combustion fumes line, in this case upstream of the thermoelectric device described later.

[0100] The fifth exchanger for combustion air increases the temperature of the heat transfer fluid and reduces the temperature of the combustion fumes.

[0101] Similarly, or alternatively, a sixth exchanger for the combustion air 6_AC can be provided, arranged on the combustion fumes line, in this case at the entrance to the enclosure.

[0102] The sixth exchanger for combustion air increases the temperature of the combustion air entering the enclosure and reduces the temperature of the combustion fumes leaving it. * Combined cycle *

[0103] According to a combined cycle principle, it is also possible to implement a set of at least one thermoelectric device 400 which makes it possible to produce electricity from heat, in addition to the electricity generated by the turbine previously described.

[0104] For example, the thermoelectric device is at least one of: an organic Rankine cycle machine, also called an ORC, which uses superheated water, steam (in this case saturated) or an organic compound as a heat transfer fluid; an expander, in particular a screw expander; a steam turbine; a thermochemical process etc.

[0105] That is to say any equipment capable of producing electricity from a heat source, preferably over 100°C and in particular over 150°C.

[0106] This electricity generation device can be implemented on at least one of: the combustion flue gas line, the treatment air line, the heat pump hot fluid circuit.

[0107] It is possible to provide for implementing a plurality of such thermoelectric devices, for example one on the combustion fumes line, another on the treatment air line, and a last one on the hot fluid circuit of the heat pump.

[0108] For example, the heat transfer fluid internal to the thermoelectric device is at a temperature of 200°C.

[0109] The thermoelectric device is also connected to the warm fluid circuit, i.e. to the useful network.

[0110] The thermoelectric device transforms part of the heat of the heat transfer fluid (200°C) into electricity. At the outlet of the thermoelectric device, the heat transfer fluid of the useful network is at a temperature of, for example, between 65°C and 95°C, and in this case 90°C, which is equivalent to a power of 862 kW of heat energy, and a power of 86 kWe, for electrical kW. * Results *

[0111] With the values ​​simulated here, thanks to the invention, we obtain a net electrical power produced equal to 413 kWe, corresponding to an electrical efficiency of 16%, and net thermal power produced equal to 2103 kW, corresponding to a thermal efficiency of 82.6%, or an overall efficiency of 98%.

[0112] The invention is not limited to the embodiments previously described. Indeed, an exchanger is configured to exchange heat between a hot source and a cold source.

[0113] Thus, any exchanger described as being placed on one of the three hot sources (process air line, combustion flue gas line and hot fluid circuit of the heat pump) can alternatively be placed on one of the other two hot sources.

[0114] The present invention is not limited to the embodiments previously described. In particular, the relative position of the exchangers may vary, as may their number. Nomenclature

[0115] 10 first compressor 20 second compressor 100 Enclosure 200 Turbine 300 Absorption heat pump (PACA) 400 Thermoelectric device _AC combustion air circuit _FC hot fluid circuit _FF cold fluid circuit _FT warm fluid circuit AT process air circuit FC combustion fumes circuit EXT outside air / atmosphere RCU useful heat network 1_AT first heat exchanger for process air 1_AC first exchanger for combustion air 2_AC second exchanger for combustion air 3_AC third exchanger for combustion air 4_AC fourth exchanger for combustion air 5_AC fifth exchanger for combustion air 6_AC sixth exchanger for combustion air 1_FC first exchanger of the hot fluid circuit 2_FC second exchanger of the hot fluid circuit 1_FT first exchanger of the warm fluid circuit 2_FT second exchanger of the warm fluid circuit 1_FF first exchanger of the cold fluid circuit 2_FF second exchanger of thecold fluid circuit

Claims

1. Open-cycle cogeneration system for thermal and electrical energy, comprising: - a set of at least one heat exchanger, configured to be connected to combustion fumes from a hearth; said set of at least one heat exchanger comprising a process air inlet and outlet (AT), - a turbine (200), configured to produce electrical energy, connected to the process air outlet of said set of at least one heat exchanger, - a process air outlet line, connecting the turbine outlet to the outside, - a combustion fumes outlet line, for evacuating the combustion fumes to the outside, - a set of at least one compressor (10, 20), configured to compress the process air at the inlet of the set of at least one heat exchanger, characterized in that it further comprises: - an absorption heat pump (300), comprising: * a hot fluid circuit (_FC), * a cold fluid circuit (_FF), * a warm fluid circuit (_FT), or useful network, and * a set of at least one exchanger for exchanging heat between at least one of the heat pump circuits and at least one of the treatment air outlet line and the combustion fumes outlet line.

2. System according to claim 1, further comprising a set of at least one thermoelectric device, making it possible to produce electricity from a heat source of more than 150°C and arranged on at least one of the treatment air outlet line and the combustion fumes outlet line.

3. System according to claim 2, wherein the thermoelectric device is at least one of: - an organic Rankine cycle machine; - an expander, in particular a screw expander; - a steam turbine.

4. The system according to any one of the preceding claims, further comprising a set of at least one exchanger for exchanging heat between at least one of: - the hot fluid circuit and the process air outlet line, - the hot fluid circuit and the combustion fumes outlet line, - the warm fluid circuit and the process air outlet line, - the warm fluid circuit and the combustion fumes outlet line, - the cold fluid circuit and the process air outlet line, and - the cold fluid circuit and the combustion fumes outlet line.

5. System according to any one of the preceding claims, further comprising an enclosure, configured to produce thermal energy and combustion fumes, and comprising said hearth and a combustion fume outlet; said set of at least one heat exchanger may be internal or external to the enclosure.

6. System according to claim 5, wherein the enclosure is one of: - a boiler, - an industrial furnace, - an incinerator.

7. System according to any one of the preceding claims, wherein the hearth comprises combustion air, said combustion air being outside air which is treated in a circuit for combustion air, said circuit for combustion air comprising at least one of: - a set of at least one exchanger for exchanging heat with the treatment air outlet line, and - a set of at least one exchanger for exchanging heat with the combustion fumes outlet line.

8. System according to any one of claims 5 to 7, comprising a heat exchanger, arranged upstream of the enclosure, and configured to preheat the treatment air at the inlet of the enclosure or at the inlet of the assembly of at least one heat exchanger connected to the combustion fumes coming from the hearth, and with the heat of the treatment air at the outlet of the turbine.

9. System according to any one of the preceding claims, in which the useful network has, at the inlet of the absorption heat pump, a temperature between 35°C and 65°C, and at the outlet of the absorption heat pump, a temperature between 40°C and 90°C.

10. System according to any one of the preceding claims, in which the useful network is an urban heat network, or an industrial process network using heat.