NZ792535B2 - Plant and process for energy generation and storage - Google Patents

Abstract

plant (1) for storing energy comprises a casing (5) for the storage of a working fluid other than atmospheric air, in gaseous phase and in equilibrium of pressure with the atmosphere; a tank (9) for the storage of said working fluid in liquid or supercritical phase with a temperature close to the critical temperature; wherein said critical temperature is close to the ambient temperature. The plant (1) is configured to perform a closed cyclic thermodynamic transformation (CTT), first in one direction in a charge configuration and then in an opposite direction in a discharge configuration, between said casing (5) and said tank (9); wherein in the charge configuration the plant (1) stores heat and pressure and in the discharge configuration the plant generates energy. The plant (1) is also configured to define a closed circuit and to perform a closed thermodynamic cycle (TC) in the closed circuit with at least a part of the working fluid, optionally while the plant (1) is in the charge configuration or in the discharge configuration.

Claims (21)

1. Energy generation and storage plant, comprising: a working fluid other than atmospheric air; a casing configured to store the working fluid in a gaseous phase and in 5 equilibrium of pressure with the atmosphere; a tank configured to store said working fluid in liquid or supercritical phase with a temperature close to the critical temperature; wherein said critical temperature is close to the ambient temperature, preferably between 0°C and 200°C; a compressor and a motor mechanically connected to each other; 10 a turbine and a generator and/or a driven machine mechanically connected to each other; wherein said casing is externally in contact with the atmosphere and delimits, at the interior thereof, a volume configured to contain the working fluid at atmospheric pressure or substantially atmospheric pressure, wherein said volume is selectively in fluid communication with an inlet of the compressor or with an 15 outlet of the turbine; a primary heat exchanger selectively in fluid communication with an outlet of the compressor or with an inlet of the turbine; wherein said tank is in fluid communication with the primary heat exchanger to accumulate the working fluid; a secondary heat exchanger operationally active between the primary heat 20 exchanger and the tank or in said tank; an additional heat exchanger operatively interposed between the casing and the compressor and/or between the casing and the turbine; a further heat exchanger operatively interposed between the turbine and the primary heat exchanger; 25 wherein the plant is configured to perform a closed cyclic thermodynamic transformation (CTT), first in one direction in a charge configuration and then in an opposite direction in a discharge configuration, between said casing and said tank; wherein in the charge configuration the plant stores heat and pressure and in the discharge configuration the plant generates energy; 30 wherein, in the charge configuration, the casing is in fluid communication with the inlet of the compressor and the primary heat exchanger is in fluid communication with the outlet of the compressor, the turbine is at rest, the motor is operating and drives the compressor to compress the working fluid coming from the casing, the primary heat exchanger works as a cooler to remove heat from the compressed working fluid, cool it and store thermal energy, the secondary heat exchanger works as a cooler to remove further heat from the compressed working fluid and store further thermal energy, the tank receives and stores the compressed and cooled working fluid, wherein the working fluid stored in the tank 5 has a temperature close to its own critical temperature; wherein, in the discharge configuration, the casing is in fluid communication with the outlet of the turbine and the primary heat exchanger is in fluid communication with the inlet of the turbine, the compressor is at rest, the secondary heat exchanger works as a heater to release heat to the working fluid coming from the 10 tank, the primary heat exchanger works as a heater to release further heat to the working fluid and heat it, the turbine is rotated by the heated working fluid and drives the generator and/or the driven machine, generating energy, the working fluid returns in the casing to atmospheric or substantially atmospheric pressure; wherein the plant is further configured to define a closed circuit and to perform a 15 closed thermodynamic cycle (TC) in said closed circuit with at least part of said working fluid, optionally while said plant is in the charge configuration or in the discharge configuration; wherein, in said closed circuit, the outlet of the compressor is in fluid communication with the further heat exchanger, the outlet of the turbine is in fluid 20 communication with the inlet of the compressor and said additional heat exchanger is operatively interposed between the outlet of the turbine and the inlet of the compressor; wherein the plant comprises: a first bypass conduit comprising a respective first valve, wherein the first 25 bypass conduit is configured to connect the outlet of the compressor with the further heat exchanger and to bypass the primary heat exchanger and the tank; a second bypass conduit comprising a respective second valve, wherein the second bypass conduit is configured to connect the outlet of the turbine with the inlet of the compressor and to bypass the casing. 30 2. Plant according to claim 1, wherein the working fluid has the following chemical-physical properties: critical temperature between 0°C and 100°C, density at 25°C between 0.5 kg/m and 10 kg/m ; and/or is preferably chosen in the group comprising: CO , SF , N O.

2. 2 6 2

3. Plant according to claim 1 or 2, wherein the casing is a pressure balloon..

4. Plant according to any of claims 1 to 3, wherein the first valve and the second valve can be throttled to adjust a flow of working fluid in the closed thermodynamic cycle (TC).

5. Plant according to any of claims 1 to 4, comprising a recuperator operatively 5 active between the primary heat exchanger and the further heat exchanger and between the outlet of the turbine and the additional heat exchanger.

6. Plant according to any of claims 1 to 5, wherein the compressor is multi- stage and inter-cooled.

7. Plant according to any of claims 1 to 6, wherein the further heat exchanger 10 is in fluid connection with at least one stage of the turbine in order to inter-heat said turbine.

8. Plant according to any of claims 1 to 7 or according to claim 8 when it depends on claim 3, wherein a pump is placed between the secondary heat exchanger and the primary heat exchanger and is configured for increasing the 15 pressure in the discharge configuration.

9. Plant according to any of claims 1 to 8, comprising delivery pipes extended from the casing to the tank and return pipes extended from the tank to the casing, wherein the first bypass conduit connects the delivery pipes with the return pipes near the primary heat exchanger and the second bypass conduit connects the 20 delivery pipes with the return pipes near the casing.

10. Process for energy generation and storage, implemented with the plant according to claim 1, wherein the process comprises: carrying out a closed cyclic thermodynamic transformation (CTT), first in one direction in a charge phase and then in an opposite direction in a discharge phase, 25 between the casing storing a working fluid different from atmospheric air, in a gaseous phase and in pressure equilibrium with the atmosphere, and the tank storing said working fluid in a liquid or supercritical phase with a temperature close to the critical temperature; wherein said critical temperature is close to the ambient temperature, preferably between 0°C and 100°C; wherein, in the charge phase, 30 the process accumulates heat and pressure and in the discharge phase the process generates energy; carrying out, with at least a part of said working fluid, a closed thermodynamic cycle (TC), optionally simultaneously with the charge phase or the discharge phase.

11. Process according to claim 10, wherein the charge phase comprises: - compressing in the compressor said working fluid, coming from said casing externally in contact with the atmosphere and delimiting at the interior thereof a volume configured to contain the working fluid at 5 atmospheric pressure or substantially atmospheric, absorbing energy; - introducing the compressed working fluid through the primary heat exchanger and the secondary heat exchanger placed in series to bring a temperature of the working fluid close to its own critical temperature; wherein the primary heat exchanger works as a cooler to remove heat 10 from the compressed working fluid, cool it and store thermal energy, wherein the secondary heat exchanger works as a cooler to remove further heat from the compressed working fluid and store further thermal energy; - accumulating the cooled working fluid in said tank; wherein the 15 secondary heat exchanger and the primary heat exchanger carry out a super-critical transformation of the working fluid so that said working fluid is accumulated in the tank in super-critical phase or wherein the secondary heat exchanger and the primary heat exchanger carry out a sub-critical transformation of the working fluid so that said working fluid 20 is accumulated in the tank in liquid phase; wherein optionally a temperature of the working fluid accumulated in the tank is between 0 °C and 100 °C and wherein a pressure of the working fluid accumulated in the tank is between 10 bar and 150 bar.

12. Process according to claim 11, wherein the discharge comprises: 25 - passing the working fluid, coming from the tank, through the secondary heat exchanger and the primary heat exchanger; wherein the secondary heat exchanger works as a heater to transfer heat to the working fluid coming from the tank, wherein the primary heat exchanger works as a heater to transfer further heat to the working fluid and heat it; 30 - passing the heated working fluid through the turbine, wherein the turbine is rotated by the heated working fluid and drives a generator and/or the driven machine, generating energy, wherein the working fluid expands and cools down in the turbine; - re-introducing the working fluid coming from the turbine into the casing at atmospheric or substantially atmospheric pressure.

13. Process according to claim 11 or 12, wherein the closed thermodynamic cycle (TC) comprises: 5 - compressing at least a part of said working fluid into the compressor; - passing said at least a part of said working fluid through the further heat exchanger operatively associated with an additional heat source; - expanding said at least a part of said heated working fluid through the turbine, wherein the turbine is rotated by the heated working fluid and drives 10 the generator and/or the driven machine, generating energy, wherein the working fluid expands and cools in the turbine; - cooling said at least a part of said working fluid in the additional heat exchanger and re-introducing said at least a part of said working fluid into the compressor. 15

14. Process according to claim 11, 12 or 13, wherein the compression of the working fluid in the compressor is inter-cooled; wherein, optionally, the closed thermodynamic cycle (TC) is recuperative.

15. Process according to one of claims 10 to 14, wherein the closed thermodynamic cycle (TC) has a higher pressure and a lower pressure; wherein 20 the higher pressure is equal to or lower than the maximum pressure of the cyclic thermodynamic transformation (CTT) in the charge phase; wherein the lower pressure is equal to or higher than the minimum pressure of the cyclic thermodynamic transformation (CTT) in the discharge phase.

16. Process according to one of the claims from 10 to 15, wherein said part of 25 the working fluid operating according to the closed thermodynamic cycle (TC) is between 0% and 50% of said working fluid, optionally between 20% and 30%; wherein the remaining part of the working fluid accumulated in the tank or in the casing is between 100% and 50% of said working fluid, optionally between 80% and 70%. 30

17. Process according to any of claims 10 to 16, wherein said working fluid has the following physical-chemical properties: critical temperature between 0 °C and 100 °C, density at 25 °C between 0.5 kg/m and 10 kg/m ; and/or it is preferably chosen in the group including: CO , SF , N O. 2 6 2

18. Process according to claim 12, wherein an expansion of the working fluid in the turbine is inter-heated.

19. Process according to claim 12, comprising: increasing the pressure in the discharge phase by means of a pump placed between the secondary heat 5 exchanger and the primary heat exchanger.

20. Energy generation and storage plant, comprising: a working fluid other than atmospheric air; a casing configured to store the working fluid in a gaseous phase and in equilibrium of pressure with the atmosphere; 10 a tank configured to store said working fluid in liquid or supercritical phase with a temperature close to the critical temperature; wherein said critical temperature is close to the ambient temperature, preferably between 0°C and 2100°C; a compressor and a motor mechanically connected to each other; a turbine and a generator and/or a driven machine mechanically connected to 15 each other; wherein said casing is externally in contact with the atmosphere and delimits, at the interior thereof, a volume configured to contain the working fluid at atmospheric pressure or substantially atmospheric pressure, wherein said volume is selectively in fluid communication with an inlet of the compressor or with an outlet of the turbine; 20 a primary heat exchanger selectively in fluid communication with an outlet of the compressor or with an inlet of the turbine; wherein said tank is in fluid communication with the primary heat exchanger to accumulate the working fluid; a secondary heat exchanger operationally active between the primary heat exchanger and the tank or in said tank; 25 an additional heat exchanger operatively interposed between the casing and the compressor and/or between the casing and the turbine; a further heat exchanger operatively interposed between the turbine and the primary heat exchanger; wherein the plant is configured to perform a closed cyclic thermodynamic 30 transformation (CTT), first in one direction in a charge configuration and then in an opposite direction in a discharge configuration, between said casing and said tank; wherein in the charge configuration the plant stores heat and pressure and in the discharge configuration the plant generates energy; wherein, in the charge configuration, the casing is in fluid communication with the inlet of the compressor and the primary heat exchanger is in fluid communication with the outlet of the compressor, the turbine is at rest, the motor is operating and drives the compressor to compress the working fluid coming from the casing, the 5 primary heat exchanger works as a cooler to remove heat from the compressed working fluid, cool it and store thermal energy, the secondary heat exchanger works as a cooler to remove further heat from the compressed working fluid and store further thermal energy, the tank receives and stores the compressed and cooled working fluid, wherein the working fluid stored in the tank has a 10 temperature close to its own critical temperature; wherein, in the discharge configuration, the casing is in fluid communication with the outlet of the turbine and the primary heat exchanger is in fluid communication with the inlet of the turbine, the compressor is at rest, the secondary heat exchanger works as a heater to release heat to the working fluid coming from the 15 tank, the primary heat exchanger works as a heater to release further heat to the working fluid and heat it, the turbine is rotated by the heated working fluid and drives the generator and/or the driven machine, generating energy, the working fluid returns in the casing to atmospheric or substantially atmospheric pressure; wherein the plant is further configured to define a closed circuit and to perform a 20 closed thermodynamic cycle (TC) in said closed circuit with at least part of said working fluid, optionally while said plant is in the charge configuration or in the discharge configuration; wherein, in said closed circuit, the outlet of the compressor is in fluid communication with the further heat exchanger, the outlet of the turbine is in fluid 25 communication with the inlet of the compressor and said additional heat exchanger is operatively interposed between the outlet of the turbine and the inlet of the compressor; wherein the plant further comprises a recuperator operatively active between the primary heat exchanger and the further heat exchanger and between the outlet of 30 the turbine and the additional heat exchanger.

21. Energy generation and storage plant, comprising: a working fluid other than atmospheric air; a casing configured to store the working fluid in a gaseous phase and in equilibrium of pressure with the atmosphere; a tank configured to store said working fluid in liquid or supercritical phase with a temperature close to the critical temperature; wherein said critical temperature is close to the ambient temperature, preferably between 0°C and 2100°C; a compressor and a motor mechanically connected to each other; 5 a turbine and a generator and/or a driven machine mechanically connected to each other; wherein said casing is externally in contact with the atmosphere and delimits, at the interior thereof, a volume configured to contain the working fluid at atmospheric pressure or substantially atmospheric pressure, wherein said volume is selectively in fluid communication with an inlet of the compressor or with an 10 outlet of the turbine; a primary heat exchanger selectively in fluid communication with an outlet of the compressor or with an inlet of the turbine; wherein said tank is in fluid communication with the primary heat exchanger to accumulate the working fluid; a secondary heat exchanger operationally active between the primary heat 15 exchanger and the tank or in said tank; an additional heat exchanger operatively interposed between the casing and the compressor and/or between the casing and the turbine; a further heat exchanger operatively interposed between the turbine and the primary heat exchanger; 20 wherein the plant is configured to perform a closed cyclic thermodynamic transformation (CTT), first in one direction in a charge configuration and then in an opposite direction in a discharge configuration, between said casing and said tank; wherein in the charge configuration the plant stores heat and pressure and in the discharge configuration the plant generates energy; 25 wherein, in the charge configuration, the casing is in fluid communication with the inlet of the compressor and the primary heat exchanger is in fluid communication with the outlet of the compressor, the turbine is at rest, the motor is operating and drives the compressor to compress the working fluid coming from the casing, the primary heat exchanger works as a cooler to remove heat from the compressed 30 working fluid, cool it and store thermal energy, the secondary heat exchanger works as a cooler to remove further heat from the compressed working fluid and store further thermal energy, the tank receives and stores the compressed and cooled working fluid, wherein the working fluid stored in the tank has a temperature close to its own critical temperature; wherein, in the discharge configuration, the casing is in fluid communication with the outlet of the turbine and the primary heat exchanger is in fluid communication with the inlet of the turbine, the compressor is at rest, the secondary heat exchanger works as a heater to release heat to the working fluid coming from the 5 tank, the primary heat exchanger works as a heater to release further heat to the working fluid and heat it, the turbine is rotated by the heated working fluid and drives the generator and/or the driven machine, generating energy, the working fluid returns in the casing to atmospheric or substantially atmospheric pressure; wherein the plant is further configured to define a closed circuit and to perform a 10 closed thermodynamic cycle (TC) in said closed circuit with at least part of said working fluid, optionally while said plant is in the charge configuration or in the discharge configuration; wherein, in said closed circuit, the outlet of the compressor is in fluid communication with the further heat exchanger, the outlet of the turbine is in fluid 15 communication with the inlet of the compressor and said additional heat exchanger is operatively interposed between the outlet of the turbine and the inlet of the compressor; wherein a pump is placed between the secondary heat exchanger and the primary heat exchanger and is configured for increasing the pressure in the discharge 20 configuration.