Cryogenic energy storage system and method of operating same - Patents.com

Abstract

The present invention relates to a cryogenic energy storage system (CESS), and in particular to a hybrid CESS that includes therein superconducting electric-based components, devices and systems that require access to cryogenic temperatures to function. The CESS comprises a cryogen storage facility, such as a tank or cylinder filled with a cryogen, such as liquid air. A cryogen expansion device is provided in the CESS for expanding stored cryogen from the cryogen storage facility when in use, and an energy generation device is provided that uses the expanded cryogen from the cryogen expansion device to generate electrical energy when in use. Advantageously, a superconducting system, including a superconducting device, is incorporated in the cryogen storage facility to function at a desired operating temperature that has no or little effect on the cryogenic energy storage system (CESS). TIFF2024538808000003.tif104170

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates to cryogenic energy storage systems (CESS), including liquid air energy storage (LAES), liquid air batteries (LAB), and the like. [Background technology]

[0002] 2. Background of the Invention A cryogenic energy storage system (singular, CESS) is an energy storage system that stores energy in the form of a cryogenic liquid, also referred to herein as "cryogen", at low temperatures for subsequent expansion, as and when required, to drive a suitable turbine to produce electrical energy. CESS are scalable and can store large amounts of energy (>250 MW.h) in an environmentally friendly manner, as the cryogenic liquid, in the form of liquid air, is typically safe, portable, and non-polluting. In this way, CESS offers an environmentally friendly option to store energy and generate electrical energy as required, as opposed to fossil fuel burning technologies such as oil or diesel generators.

[0003] A CESS typically has three stages or sections: (i) liquefaction of a gaseous cryogen such as air using electrical energy, (ii) storage of the liquid air in a tank, and (iii) expansion of the liquid air to power a turbine to generate electrical energy, as shown below. TIFF2024538808000002.tif14131

[0004] In summary, a CESS uses electricity (which may be renewable based) to cool a cryogen gas, such as air, until it liquefies. This liquid air is stored in a suitable tank. The liquid cryogen becomes a dynamic gas state when exposed to ambient air or by waste heat, and the energized gas turns a turbine to generate electricity.

[0005] The inventors have determined that CESS and other technologies that require low temperatures (to the extent that the cryogen in the form of liquid air is in a liquid state) to operate or function efficiently may be mutually beneficially or synergistically optimized or enhanced by integrating the technology with, and particularly as part of, the CESS. Summary of the Invention

[0006] According to a first aspect of the present invention, there is provided a method for producing a cellular membrane comprising the steps of: a cryogen storage facility for storing or adapted to store a cryogen; a cryogen expansion device configured, in use, to expand cryogen received from the cryogen storage facility; an energy generating device configured, in use, to be powered by the expanded cryogen from the cryogen expansion device to generate electrical energy; and a superconducting device positioned within a cryogen storage facility such that the superconducting device is cooled by a cryogen stored in the cryogen storage facility; A cryogenic energy storage system is provided comprising:

[0007] The cryogen stored in the cryogen storage facility may be liquid air or liquid nitrogen. Liquid air is comprised mostly of liquid nitrogen (78%). In this regard, the cryogen storage facility may maintain the cryogen therein at a temperature of approximately 78.8 K, between the boiling points of liquid nitrogen (77.36 K) and liquid oxygen (90.19 K), at 1 atmosphere pressure. It will be appreciated that the temperature of the cryogen may be maintained at a temperature below the boiling point of the cryogen (approximately 78.8 K if the cryogen is in the form of liquid air) and above the freezing point of the cryogen (58.0 K if the cryogen is in the form of liquid air and 63.1 K for liquid nitrogen).

[0008] The superconducting device may be a high temperature superconducting device and / or may include or be constructed from a superconducting material. In this regard, the superconducting system / device is configured to operate at a higher cryogenic temperature of about 78K (-197°C), which may be the approximate temperature at which the cryogen in the cryogen storage facility is stored. Thus, the temperature of the cryogen in the cryogen storage facility is advantageously below the critical temperature (Tc) of the superconducting / superconductor material present in the superconducting device or of which the superconducting / superconductor device is constructed. In this manner, the presence of the superconducting device in the cryogen storage facility advantageously eliminates the need for and associated costs of a dedicated superconductor device cooling system, since most superconducting devices generate little or no heat due to their zero-resistance superconducting properties, and appear thermally transparent to the cryogen tank.

[0009] The superconducting device may be selected from a group including a superconducting magnetic energy storage (SMES) device, a superconducting transformer (ST), and a superconducting current limiter (SFCL). It is noted that in some exemplary embodiments, a superconducting system may include a plurality of superconducting devices, for example, selected from the group of superconducting devices listed above.

[0010] Superconducting devices may be maintained at operating temperatures below Tc by cryogenic storage facilities, reducing the cost and complexity of providing dedicated cooling systems for superconducting devices.

[0011] The SMES device may be configured to generate electrical energy instead of or in addition to the electrical energy generated by the energy generating device. In particular, the SMES device may be configured to supply power to a load before the energy generating device supplies power to the load operably connected to the cryogenic energy storage system. This helps to address applications such as load leveling and to balance short-term transient faults due to the high power response as described herein. In some exemplary embodiments, the electrical energy generated by the energy generating device may be used to charge the SMES device.

[0012] The SFCL may be electrically coupled to the grid and to the load, and the SFCL may be configured to limit a fault current from the grid reaching the load. Similarly, the ST may be electrically coupled to the grid and / or the load.

[0013] In one exemplary embodiment, the cryogen storage facility may comprise a suitable cryogen storage tank for storing or configured to store the cryogen and for housing at least the superconducting device therein. In this regard, it is noted that the superconducting system, and in particular the superconducting device, may be incorporated into the cryogen storage tank.

[0014] Cryogenic energy storage systems include: Storage devices, a processor coupled to the storage device; and one or more sensors operably disposed within the cryogen storage tank and operably connected to the processor for measuring one or more parameters and transmitting data indicative thereof to the processor, the processor being configured to activate an appropriate alarm protocol in response to determining that the one or more measured parameters are unacceptable; The present invention may also include:

[0015] In particular, the system may include a suitable level sensor communicatively coupled to the processor for measuring the amount of cryogen stored in the cryogen storage tank, the processor being configured to activate an appropriate alarm protocol in response to determining that the amount of cryogen in the cryogen storage tank measured by the level sensor is below a minimum operational amount / level / volume of cryogen required for the superconducting device. In this manner, the cryogen in the cryogen storage tank may be used to generate electrical energy by the energy generating device, but not to an amount or extent that would affect the cooling of the superconducting device as described herein. It thus follows that the minimum operational amount / level / value of cryogen required for the superconducting device is the amount of cryogen required to adequately cool the superconductor device such that the superconducting device is maintained and / or operates in a superconducting state.

[0016] The system may include a suitable vibration sensor communicatively coupled to the processor for sensing vibrations of or within the cryogen storage tank, the processor being configured to activate an appropriate alarm protocol in response to determining that the vibrations sensed by the vibration sensor are unacceptable. The vibration sensor may be a conventional piezoelectric vibration sensor. The superconducting device may trigger a quench event based on vibrations exceeding a threshold.

[0017] The system may include a suitable pressure sensor communicatively coupled to the processor for measuring a pressure in the cryogen storage tank, the processor being configured to activate an appropriate alarm protocol in response to determining that the pressure in the cryogen storage tank measured by the pressure sensor is unacceptable. The cryogen storage tank may include a suitable valve for boil-off of the cryogen. The cryogen storage tank may further include a second valve for addressing excess steam generation if an overpressure event, such as a quench, is detected by the processor. The processor may be configured to control the valve. If the processor determines that the measured pressure exceeds the maximum pressure, the processor may be configured to activate the alarm protocol by at least disconnecting / purging energy from / to the superconducting device.

[0018] The system may include a temperature sensor communicatively coupled to the processor for measuring a temperature of the cryogen stored in the cryogen storage tank, the processor configured to activate an appropriate alarm protocol in response to determining that the temperature of the cryogen in the cryogen storage tank measured by the temperature sensor is outside a predetermined temperature range. The system may include multiple temperature sensors for sensing / measuring the temperature of the stored cryogen and / or the cryogen storage tank, in particular the uniformity of the temperature of the cryogen. As suggested herein, if the cryogen is liquid air, the predetermined temperature range is above the freezing point of liquid air, e.g., 58.0 K, but below the boiling point of liquid air, e.g., 78.8 K. It is noted that the alarm protocol may include disconnecting / purging energy from / to the superconducting device, as necessary, to counter a critical superconductor quench event if the measured temperature is not within the predetermined temperature range.

[0019] In summary, some of the alarm protocols contemplated herein may include one or more of: disconnecting / purging energy from / to the superconducting device and generating an appropriate alarm signal to activate an appropriate alarm device, which may be a siren, light, etc. to alert system operators and / or maintenance personnel.

[0020] In one exemplary embodiment, the system may include a suitable vacuum pump operably connected to the cryogen storage tank, where a suitable alarm protocol includes operating the vacuum pump to reduce the vapor pressure in the cryogen storage tank, thereby reducing the temperature of the cryogen in the cryogen storage tank to bring the temperature within a predetermined temperature range. This may be done in response to a temperature measured by a temperature sensor being outside, typically above, a contemplated range for the cryogen in the cryogen storage tank.

[0021] To ensure a uniform temperature of the cryogen in the cryogen storage tank, the cryogen storage tank may include a suitable stirring device, such as an agitator, positioned within the cryogen storage tank to at least maintain a uniform temperature within the cryogen storage tank. It will be appreciated that the processor may be configured to operate the agitator in response to determining that the temperature distribution of the cryogen in the cryogen storage tank is not homogeneous. Alternatively, or in addition, the processor may be configured to operate the agitation periodically, for example at predetermined time intervals, to ensure uniformity of the temperature of the cryogen in the cryogen storage tank.

[0022] In one exemplary embodiment, the cryogen storage facility may include one or more primary cryogen storage tanks configured to store or store cryogen, and at least one secondary cryogen storage tank configured to store or store cryogen and housing a superconducting device. Thus, the secondary cryogen storage tank may be a cryogen storage tank that houses or is configured to store a superconducting device as described above, and the primary storage tank stores cryogen for use in generating electrical energy by the energy generating device, and optionally for replenishing the cryogen in the secondary cryogen storage tank. The primary and secondary cryogen storage tanks may be in controlled fluid communication with each other.

[0023] It should be noted that in the last-mentioned exemplary embodiment, the primary cryogen storage tank typically supplies cryogen to a cryogen expansion device, while the secondary cryogen storage tank is configured to house the superconducting system. For simplicity, the terms "primary tank" and "primary cryogen storage tank" may be used interchangeably herein. Similarly, the terms "secondary tank" and "secondary cryogen storage tank" may be used interchangeably herein.

[0024] All of the cryogen storage tanks described herein may be insulated cryogen storage tanks.

[0025] The secondary storage tank may receive the cryogen from the primary storage tank and may be configured to maintain the cryogen therein at a lower temperature than the primary storage tank. To this end, the system may include a suitable pump for moving the cryogen between the primary and second cryogen storage tanks. The pump may be operatively positioned within or adjacent to the primary cryogen storage tank for pumping the cryogen from the primary cryogen storage tank to the secondary cryogen storage tank so as to maintain a predetermined minimum operating amount / level / volume of the cryogen in the secondary cryogen storage tank.

[0026] The systems described herein may include a suitable processor communicatively coupled to the pump to control the pump to pump cryogen from the primary cryogen storage tank to the secondary cryogen storage tank upon detecting that the cryogen level in the secondary cryogen storage tank falls below a predetermined minimum operating amount / level. To this end, the secondary cryogen storage tank may include a suitable level sensor to sense the level or volume of cryogen in the secondary cryogen storage tank.

[0027] The system may include a suitable temperature reduction assembly configured to reduce the temperature of the cryogen in the secondary cryogen storage tank. In one exemplary embodiment, the temperature reduction assembly may preferably include a vacuum pump configured to reduce vapor pressure in the secondary cryogen storage tank, where operation of the vacuum pump reduces the temperature of the cryogen in the secondary cryogen storage tank.

[0028] In one exemplary embodiment, the secondary tank may include a suitable temperature sensor operably coupled to the processor and configured to sense a temperature of the cryogen in the secondary tank, wherein the processor is configured to operate the vacuum pump in response to determining via the temperature sensor that the temperature of the cryogen in the secondary cryogen storage tank is not within a desired temperature range or exceeds a predetermined temperature threshold.

[0029] The secondary cryogen-storage tank may be pneumatically isolated from the primary cryogen-storage tank when the vacuum pump is operated, which may be accomplished by an appropriate valve in the fluid flow path between the primary and secondary cryogen-storage tanks.

[0030] In one exemplary embodiment, the primary cryogen storage tank may be one of a plurality of primary cryogen storage tanks. Similarly, the secondary cryogen storage tank may be one of a plurality of secondary cryogen storage tanks. In one exemplary embodiment, the primary storage tank may have a capacity of about 2000 liters of cryogen. One or both of the primary and secondary cryogen storage tanks may be constructed entirely or partially from non-metallic materials to at least reduce inductive heating of the vessel.

[0031] The cryogen expansion device may include a suitable heat exchanger configured to heat the cryogen using heat from one or more of ambient air, geothermal heat, waste heat from a power plant, and waste heat from a manufacturing plant to expand the cryogen.

[0032] The energy generating device is: a turbine configured, in use, to be powered by expanded cryogen from the cryogen expansion device; and a generator configured, in use, to be operated by the turbine to generate electrical energy; The present invention may also include:

[0033] In one exemplary embodiment, the system may include an air liquefaction device configured to liquefy air for storage in the cryogen storage facility. In one exemplary embodiment, the air liquefaction device may be configured to provide liquefied air for storage in the primary cryogen storage tank.

[0034] According to a second aspect of the present invention, there is provided a method of operating a cryogenic energy storage system, comprising: storing the cryogen in a cryogen storage facility; expanding the stored cryogen received from the cryogen storage facility; generating electrical energy by operating a suitable energy generating device using the expanded cryogen; Providing a superconducting device within the cryogenic storage facility; and A process for cooling a superconducting device with a cryogen stored in a cryogen storage facility. A method is provided that includes:

[0035] The cryogenic energy storage system may be similar to the systems described herein, and thus any descriptions relating to the system apply mutatis mutandis to any of the outlines of methodologies for operating such cryogenic energy storage systems described herein.

[0036] The method may include operating the SMES to generate electrical energy instead of, or in addition to, the electrical energy generated by the energy generating apparatus. The method further includes charging the SMES device, during use, with the electrical energy generated by the energy generating apparatus.

[0037] The method may include operating the SMES device to supply power to a load operably connected to the cryogenic energy storage system before the energy generating device supplies power to the load.

[0038] Here's how to do it: measuring one or more parameters associated with the cryogen storage tank and / or associated with the cryogen stored in the cryogen storage tank; transmitting the measured parameters to a suitable processor communicatively coupled to a suitable storage device; and activating an appropriate alarm protocol in response to determining that one or more measured parameters are unacceptable. may include:

[0039] The method may include measuring an amount of cryogen stored in the cryogen storage tank, and activating an appropriate alarm protocol by the processor in response to determining that the amount of cryogen in the cryogen storage tank is below a minimum operating amount of cryogen required for the superconducting device stored in the cryogen storage tank.

[0040] The method may include sensing or measuring vibrations at or within the cryogen storage tank, and activating an appropriate alarm protocol by a processor in response to determining that the sensed vibrations are unacceptable.

[0041] The method may include measuring the pressure in the cryogen storage tank and activating an appropriate alarm protocol by the processor in response to determining that the measured pressure is unacceptable.

[0042] The method may include measuring a temperature of the cryogen stored in the cryogen storage tank, and activating an appropriate alarm protocol by the processor in response to determining that the temperature of the cryogen in the cryogen storage tank is outside a predetermined temperature range.

[0043] An appropriate alarm protocol may include operating a vacuum pump operably connected to the cryogen storage tank to reduce the vapor pressure within the cryogen storage tank, thereby reducing the temperature of the cryogen within the cryogen storage tank to bring the temperature within a predetermined temperature range.

[0044] The predetermined temperature range may be limited by a temperature below the boiling point of the cryogen and above the freezing point of the cryogen.

[0045] The method may include operating a suitable agitation device within the cryogen storage tank to at least maintain a uniform temperature within the cryogen storage tank.

[0046] The cryogen storage facilities are as follows: one or more primary cryogen storage tanks, configured to store or store a cryogen; and at least one secondary cryogen storage tank configured to store or store a cryogen, the primary and secondary cryogen storage tanks being in controlled fluid communication with each other, the secondary cryogen storage tank housing a superconducting device, the method including the steps of: transferring cryogen from the primary cryogen storage tank to the secondary cryogen storage tank in response to detecting a level of cryogen in the secondary cryogen storage tank falling below a predetermined threshold; and / or transferring cryogen from the secondary cryogen tank to the primary cryogen tank up to a minimum volume of cryogen required in the secondary tank for the superconducting device. The present invention may also include:

[0047] The method may include reducing the vapor pressure in the secondary cryogenic storage tank by operating a suitable vacuum pump operably connected to the secondary tank as described herein.

[0048] The method may include maintaining a temperature of the cryogen in the primary cryogen storage tank below the boiling point of the cryogen.The method may include maintaining a temperature of the cryogen in the secondary cryogen storage tank within a temperature range below the boiling point of the cryogen and above the freezing point of the cryogen.

[0049] According to a third aspect of the present invention, there is provided a cryogen storage facility for storing or configured to store a cryogen, comprising a superconducting device within the cryogen storage facility such that the superconducting device is cooled by cryogen stored in the cryogen storage facility.

[0050] The cryogen storage facility may be substantially similar to the cryogen storage facilities described herein.

[0051] According to a fourth aspect of the present invention, there is provided a method of cooling a superconducting device, comprising: Positioning the superconducting device within a cryogenic storage facility associated with a cryogenic energy storage system; and A process for cooling a superconducting device with a cryogen stored in a cryogen storage facility. A method is provided that includes:

[0052] It will be appreciated by those skilled in the art that the description of one aspect of the invention provided herein may be extended / applied mutatis mutandis to other aspects of the invention described herein. [Brief description of the drawings]

[0053] [Figure 1] FIG. 1 is a high-level schematic block diagram of a cryogenic energy storage system in accordance with an exemplary embodiment of the present invention. [Diagram 2] 1 is a schematic diagram of a cryogen storage facility including a cryogen storage tank having a superconducting device integrated therein, in accordance with an exemplary embodiment of the present invention; [Diagram 3] 2 is a schematic diagram of another example of a cryogen storage facility including a primary cryogen storage tank and a secondary cryogen storage tank having a superconducting device installed therein, in accordance with an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Description of the Preferred Embodiments The following description of the invention is provided as an enabling teaching of the invention. Those skilled in the art will recognize that many variations can be made to the described embodiments while still achieving the beneficial results of the invention. It will also be apparent that some of the desired advantages of the invention can be achieved by selecting some of the features of the invention without utilizing other features.

[0055] Accordingly, those skilled in the art will recognize that modifications and adaptations to the present invention are possible, and even desirable in certain circumstances, and are a part of the present invention. Accordingly, the following description is provided as an illustration of the principles of the invention, and not in limitation thereof.

[0056] It will be understood that the phrases "for example," "such as," and variations thereof describe non-limiting aspects of the subject matter of the present disclosure. When reference is made herein to "one exemplary embodiment," "another exemplary embodiment," "an exemplary embodiment," or variations thereof, it means that the particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the subject matter of the present disclosure. Thus, use of the phrases "one exemplary embodiment," "another exemplary embodiment," "an exemplary embodiment," or variations thereof does not necessarily refer to the same embodiment.

[0057] Unless otherwise stated, certain features of the subject matter described herein that are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Similarly, various features of the subject matter disclosed herein that are described in the context of a single embodiment may also be provided separately or in any suitable subcombination.

[0058] The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. For the sake of brevity, the word "may" is used in its permissive sense (i.e., meaning "may") rather than its mandatory sense (i.e., meaning "must").

[0059] The words "include," "including," and "includes," as well as "comprises," "comprising," and "comprises," mean including and including, but not limited to, respectively. Additionally, as used herein, the term "coupled" may refer to two or more components being connected to one another, whether the connection is permanent (e.g., welding, casting, molding, carving) or temporary (e.g., bolting, screwing, gluing via adhesive), direct or indirect (i.e., through an intermediary), mechanical, chemical, optical, or electrical, as in the case of communicatively coupled components that may communicate with one another wirelessly or in a hard-wired manner.

[0060] Referring to FIG. 1 of the drawings, a cryogenic energy storage system (CESS) is provided, generally designated by reference numeral 10. The CESS 10 is typically a hybrid CESS used to store energy that may be released therefrom in the form of electrical energy to power one or more loads operatively connected to the CESS 10. To this end, the CESS 10 may be used as a backup electrical energy generator to supply electrical energy to the loads when other energy sources, such as a city power grid, are unavailable / offline. Alternatively, or in addition, the CESS 10 is configured to supply cheaper or more environmentally friendly electrical energy to the loads, whether or not they are connected to a city power grid. To this end, the CESS 10 may be equipped with various power electronic components, devices and appliances (not shown) to enable them to be interfaced with said loads and / or the power grid.

[0061] In a preferred exemplary embodiment, the CESS 10, or a portion thereof, is located adjacent to a source of waste heat from a manufacturing / industrial process, such as a factory, that generates heat that would normally be lost.

[0062] The CESS 10 comprises a cryogen storage facility 12 that stores or is configured to store a cryogen, e.g., liquid air consisting primarily of nitrogen. While other cryogenic materials may be used as the stored cryogen, and referring to an exemplary embodiment in which the cryogen is liquid air, the terms "cryogen" and "liquid air" may be used interchangeably herein. Although not shown, the CESS 10 may comprise or be in communication with a suitable air liquefaction system that may be employed to liquefy the air to be stored in the storage facility 12.

[0063] The CESS 10 also includes a cryogen expansion device 14 having a suitable heat exchanger (not shown) for expanding the stored cryogen, and an energy generation / generation device 16 configured, in use, to be powered by the expanded cryogen from the cryogen expansion device 14 to generate electrical energy. Although not shown, the energy generation device 16 may include a suitable turbine and a suitable generator, the turbine configured to be powered by the expanded cryogen from the expansion device 14, the turbine powering the generator to generate electrical energy in a conventional manner.

[0064] The CESS 10, and in particular at least the cryogenic expansion device 14, may be located proximate to a waste heat source as described herein.

[0065] The CESS 10 further comprises a superconducting device 18 positioned within the cryogen storage facility 12 such that the superconducting device 18 is cooled by the cryogen stored in the cryogen storage facility 12. In this manner, the need for a dedicated and expensive cooling system associated with the superconducting device 18 is eliminated.

[0066] The superconducting device 18 may be a device that includes or is fabricated from a superconducting material. In this regard, the superconducting device may be selected from the group including a superconducting magnetic energy storage (SMES) device, a superconducting electronic device, a superconducting transformer (ST), and a superconducting current limiter (SFCL).

[0067] For ease of explanation, reference will be made to a superconducting device 18 in the form of a SMES device 18. However, those skilled in the art will appreciate that the principles taught herein may be applied mutatis mutandis to other superconducting devices and / or components.

[0068] The SMES device 18 is typically configured to store and output electrical energy on demand, instead of or in addition to electrical energy generated by the energy generating device. In comparison to the CESS, the SMES device 18 is typically a high-power, low-energy device, and thus the SMES device 18 is configured to supply electrical power to a load operatively connected to the CESS 10 before the energy generating device 16 supplies electrical power to the load. In other words, the SMES device 18 is configured to supply electrical energy to the load relatively quickly while the energy generating device 16 starts up to supply electrical energy to the load.

[0069] The SMES device 18 is typically stored within the cryogen storage facility 12. In particular, and also referring to FIG. 2 of the drawings, the SMES device 18 is conveniently located within a cryogen storage tank 30 of the cryogen storage facility. As suggested herein, the SMES device 18 is conveniently cooled to a temperature not exceeding 78.8 K by the cryogen in the tank 30 to prevent liquid air boil-off and / or to assist in cooling the SMES device 18 to within desired parameters. In some exemplary embodiments, the CESS 10 may include a suitable vacuum pump (not shown) to further reduce the temperature of the cryogen in the cryogen storage tank 30 to a temperature just above its freezing temperature, typically above 58 K.

[0070] Tank 30 may be constructed from non-metallic materials, or the majority of tank 30 may be constructed from non-metallic materials. Additionally, tank 30 may be insulated, for example by a suitable thermal jacket, and may be sealed except for ports / valves as contemplated herein. In one exemplary embodiment, tank 30 may be a 2000 liter tank that stores or is configured to store a liquid air cryogen, with the tank having a predetermined minimum level L of cryogen that must be stored therein to adequately cool superconducting device 18.

[0071] Tank 30 may be provided with suitable vents, etc., as well as inlet and / or outlet ports (not shown) for the introduction and removal of liquid air cryogen from tank 30.

[0072] The CESS 10 advantageously comprises a sensor arrangement comprising one or more sensors 24 (FIG. 1) disposed within and / or about the tank 30 for measuring and / or sensing various parameters associated with the tank 30, and in particular the cryogen stored within the tank. To this end, the CESS 10 described herein comprises a suitable storage device 22 and a suitable processor 20 communicatively coupled to the sensors 24 for receiving the measured and / or sensed parameters and / or information indicative of the parameters.

[0073] The processor 20 may typically be one or a combination of a microcontroller, a processor, a graphics processor, or a field programmable gate array (FPGA) operable to achieve the desired operations described herein. The processor 20 may be operable under instructions stored in an internal memory or an external storage device 22 to perform the operations described herein.

[0074] The processor 20 is typically configured to activate an appropriate alarm protocol in response to determining that one or more measured parameters are unacceptable. In this regard, the CESS 10 includes a suitable level sensor (not shown) communicatively coupled to the processor 20 for measuring or monitoring the amount of cryogen stored in the cryogen storage tank 30. In particular, the processor 20 is configured to activate an appropriate alarm protocol in response to determining that the level of cryogen in the cryogen storage tank, as measured by the level sensor, falls below a minimum operating level L of cryogen required for the superconducting device 18. In this manner, the cryogen stored in the tank 30 may be used to generate electrical energy by the devices 14 and 16, but the tank 30 is never depleted of cryogen to a level that would affect the ability of the cryogen stored in the tank to adequately cool the superconducting device 18.

[0075] In some exemplary embodiments, the CESS 10 includes a suitable vibration sensor (not shown) communicatively coupled to the processor 20 for sensing vibrations of or within the cryogen storage tank 30. The processor 20 is configured to activate an appropriate alarm protocol in response to determining that the vibrations sensed by the vibration sensor are unacceptable. In this manner, the integrity of the CESS 10 may be preserved.

[0076] In certain exemplary embodiments, the CESS 10 includes a suitable pressure sensor communicatively coupled to the processor 20 for measuring the pressure within the cryogen storage tank 30. The processor 20 is configured to activate an appropriate alarm protocol in response to determining that the pressure within the cryogen storage tank measured by the pressure sensor is unacceptable.

[0077] The CESS 10 advantageously includes a number of temperature sensors (not shown) communicatively coupled to the processor 20 for measuring the temperature of the cryogen stored in the cryogen storage tank. The temperature sensors may be positioned at various locations within the cryogen storage tank 30 to measure at least the uniformity of the cryogen stored in the tank. It will be appreciated that the processor 20 is configured to activate an appropriate alarm protocol in response to determining that the temperature of the cryogen in the cryogen storage tank, as measured by the temperature sensors, is outside of a predetermined temperature range or set point, for example, if the temperature exceeds 78.8K. In this regard, if the processor 20 determines that the temperature of the cryogen in the tank 30 is rising above 78.8K, the processor 20 is configured to operate an appropriate vacuum pump as described above to reduce the vapor pressure within the cryogen storage tank 30, thereby reducing the temperature of the cryogen in the cryogen storage tank 30 to bring the temperature within the predetermined temperature range or below the set point of 78.8K.

[0078] It should be noted that the alarm protocol includes one or more of: disconnecting / purging energy from / to the superconducting device 18, and generating an appropriate alarm signal to activate an appropriate alarm device, such as a siren.

[0079] In one exemplary embodiment, the cryogen storage tank 30 is equipped with a suitable agitation device, such as an agitator (not shown), controllable by the processor 20 to at least maintain a uniform temperature within the cryogen storage tank 30 .

[0080] Referring now to FIG. 3 of the drawings, another exemplary embodiment of a storage facility 112 is illustrated in accordance with an exemplary embodiment of the present invention. The storage facility 112 illustrated in FIG. 3 includes a cryogen storage tank 30 similar to the tank 30 described above with reference to FIG. 2, and thus like parts are referenced with the same reference numerals. However, the storage facility 112 includes a primary cryogen storage tank 32 configured to store or store cryogen in selective fluid communication with the tank 30, which may be referred to herein as a secondary tank 30. It should be noted that the primary tank 32 may be similar to the tank 30, but does not house the superconducting device 18 therein, and is primarily used to store cryogen for purposes of operating the apparatus 14 and the apparatus 16, and optionally to replenish the cryogen in the tank 32. The tank 30, on the other hand, is used to house the superconducting device 18 and / or optionally store cryogen for use by the apparatus 14 and the apparatus 16 up to a predetermined level L. Although only one primary tank 30 and one secondary tank 32 are illustrated, it will be understood that the facility 112 may have multiple primary tanks 32 and, optionally, multiple secondary tanks 30 that house or are configured to house superconducting devices 18 therein.

[0081] It should be noted that the CESS may, if desired, include a suitable pump P and valve V1 disposed between tanks 30 and 32 to control the flow of cryogen from primary tank 32 to secondary tank 30. In one exemplary embodiment, processor 20 is configured to operate pump P and valve V1 to move cryogen from tank 32 to tank 30, for example, when processor 20 determines, via a level sensor, e.g., a capacitive level sensor, that the level of cryogen in tank 30 falls below a predetermined minimum level L.

[0082] As described above and as illustrated in FIG. 3, CESS10 includes a suitable vacuum pump Pv and valve V2, and the processor 20 is configured to operate the vacuum pump Pv and optionally the valve V2 to reduce the vapor pressure in the tank 30, thereby reducing the temperature of the refrigerant in the tank 30 within a predetermined temperature range, for example, 58K < T < 78K.

[0083] Referring to FIGS. 1 to 3 of the drawings, in use, CESS10 stores the refrigerant at a temperature below 78K in the storage facilities 12, 112, particularly in the tanks 30, 32. Further, CESS10 houses a superconducting device such as the SMES device 18 in one of the tanks 30.

[0084] When power is required by the load, CESS10 operates such that the SMES18 is activated simultaneously with the release of the refrigerant to the expansion device 14 and the energy generation device 16. However, due to the high-power nature of the SMES device 18, the SMES device 18 supplies power to the load before the energy generation device 16, thus substantially reducing the delay in the supply of electrical energy to the load associated with the device 16 in certain scenarios in response to the load demand. It should be noted that in some exemplary embodiments, the SMES device 18 may operate to supply power to the load without the CESS10 operating to generate electrical energy by the release of the refrigerant to the expansion device 14 and the operation of the energy generation device 16.

[0085] In the case of the facility 112, the refrigerant is typically utilized from the primary tank 32. However, when the need arises, or in the case of the storage facility 12 having only the tank 30, the refrigerant is typically discharged from the tank 30 to the expansion device 14 to power the energy generation device 16. However, the processor 20 monitors the level of the refrigerant in the tank 30 by means of a level sensor. If the processor 20 determines that the level of the refrigerant in the tank 30 is below a predetermined minimum level L, the processor 20 may be configured to operate the pump P and the valve V1 to replenish the refrigerant in the tank 30.

[0086] Furthermore, the processor 20 controls the stirrer in the tank 30 so as to ensure that the temperature distribution is uniform. However, if the processor 20 determines via the temperature sensor that the temperature in the tank 30 is not uniform and / or the stirrer is not operating, the processor 20 activates an appropriate alarm protocol to indicate that the stirrer is not operating. Similarly, an alarm protocol may be activated by the processor 20 in response to determining via an appropriate sensor 24 that the pressure in the tank 30 or the vibration sensed within / of the tank 30 is unacceptable.

[0087] In one exemplary aspect, if the processor 20 determines that the temperature of the cryogen in the tank 30 exceeds a set temperature value Ts (58K < Ts < 78K) that is between the cryogen freezing point and the cryogen boiling point, the processor 20 is configured to operate the vacuum pump Pv and optionally the valve V2 to reduce the vapor pressure in the tank 30 and thereby reduce the temperature of the cryogen in the tank 30. In the case of the facility 112, the vacuum pump Pv can be operated to bring the temperature of the internal cryogen to between 58K and 78K.

[0088] Liquid air may be supplied to the storage facilities 12, 112 via a suitable liquid air liquefaction system.

[0089] The resulting hybrid system described herein seeks to reduce the capital and operating costs of the independent cryogenic cooling systems required for superconducting devices / systems. By pumping on the cryogen storage facility (tank) with a vacuum pump, the vapor pressure is reduced, resulting in a lower temperature of the cryogen, and as a result, the performance of the superconducting devices within the tank housing the superconducting devices is improved.

[0090] When the CESS is charged by a renewable energy source such as solar power generation (PV) or a wind turbine, a 100% environmentally friendly power source is realized. In this regard, in some exemplary aspects, the CESS may be charged by a renewable energy source.

[0091] Voltage and power fluctuations in power systems can result from a variety of events, for example, clouds passing over a PV farm can affect the solar irradiance received by the PV farm. These fluctuations can have adverse effects on loads directly connected to the PV, for example: (i) causing changes in the torque of electric machines, which results in machine vibrations and degradation, and (ii) in uninterruptible power supplies (UPS), utilization of UPS batteries for short-term events can affect battery life.

[0092] The CESS, where energy is stored as cryogen, can inherently scale to the required operating temperature of the SMES. This hybrid CESS / SMES system is suitable for mitigating power fluctuations as mentioned above using the SMES power response, e.g. during longer blackout periods when the CESS is used, when there is no electrical energy produced by the PV farm (at night).

Claims

1. storing or configured to store a cryogen; (a) one or more primary cryogen storage tanks (32); and (b) at least one secondary cryogen storage tank (30); a cryogen storage facility (112) comprising: a cryogen expansion device (14) configured, in use, to expand cryogen received from the cryogen storage facility (112); a suitable energy generating device (16) configured, in use, to be powered by the expanded cryogen from the cryogen expansion device (14) to generate electrical energy; a superconducting device (18) positioned within the cryogen storage facility (112) such that, in use, the superconducting device is cooled by a cryogen stored in the cryogen storage facility (112); a suitable pump (P) and a suitable valve (V1) provided in the fluid flow path between the one or more primary cryogen storage tanks (32) and the at least one secondary cryogen storage tank (30) for controlling the flow of cryogen from the primary tank (32) to the secondary tank (30), as required; Equipped with the secondary cryogen storage tank (30) is a suitably insulated cryogen storage tank and contains at least the superconducting device (18) therein; Cryogenic energy storage systems (10).

2. 2. The cryogenic energy storage system of claim 1, wherein the superconducting device is selected from the group consisting of a superconducting magnetic energy storage (SMES) device, a superconducting electronic device, a superconducting transformer (ST), and a superconducting fault current limiter (SFCL).

3. A cryogenic energy storage system (10) as described in any one of claims 1 or 2, wherein the cryogen storage facility (112) comprises a suitable temperature reduction assembly configured to reduce the temperature of the cryogen in the at least one secondary cryogen storage tank (30), and optionally the temperature reduction assembly further comprises a vacuum pump configured to reduce the vapor pressure in the secondary storage tank, and in use operation of the vacuum pump reduces the temperature of the cryogen in the secondary cryogen storage tank.

4. Storage devices (22), a processor (20) coupled to the storage device (22); and one or more sensors (24) operably disposed within the cryogen storage tank (30) and operably connected to the processor (20) for measuring one or more parameters and transmitting data indicative thereof to the processor (20), the processor (20) being configured to activate an appropriate alarm protocol in response to determining that one or more measured parameters are unacceptable; and optionally, a suitable level sensor communicatively coupled to the processor for measuring or monitoring the amount of cryogen stored in the cryogen storage tank, the processor being configured to activate an appropriate alarm protocol in response to determining that the amount of cryogen in the cryogen storage tank as measured by the level sensor is below a minimum operating amount of cryogen required for the superconducting device; and / or a suitable vibration sensor communicatively coupled to the processor for sensing vibrations of or within the cryogen storage tank, the processor configured to activate an appropriate alarm protocol in response to determining that the vibrations sensed by the vibration sensor are unacceptable; and / or a suitable pressure sensor communicatively coupled to the processor for measuring the pressure within the cryogen storage tank, the processor being configured to activate an appropriate alarm protocol in response to determining that the pressure within the cryogen storage tank measured by the pressure sensor is unacceptable; and / or a temperature sensor communicatively coupled to the processor for measuring the temperature of the cryogen stored in the cryogen storage tank, the processor being configured to activate an appropriate alarm protocol in response to determining that the temperature of the cryogen in the cryogen storage tank measured by the temperature sensor is outside a predetermined temperature range or set point; The cryogenic energy storage system (10) of claim 3.

5. 5. The cryogenic energy storage system (10) of claim 3 or 4, wherein the cryogen storage tank (30) is provided with a suitable stirring device to at least maintain a uniform temperature within the cryogen storage tank (30).

6. 6. The cryogenic energy storage system (10) of claim 5, wherein the pump (P) is operably positioned within or adjacent to the primary cryogen storage tank (32) to pump cryogen from the primary cryogen storage tank (32) to the secondary cryogen storage tank (30) to maintain a predetermined level of cryogen in the secondary cryogen storage tank (30).

7. 7. The cryogenic energy storage system (10) of claim 6, wherein the temperature of the cryogen in the primary cryogen storage tank (32) is a temperature below the boiling point of the cryogen, and the temperature of the cryogen in the secondary cryogen storage tank (30) is within a temperature range below the boiling point of the cryogen and above the freezing point of the cryogen.

8. 8. The cryogenic energy storage system (10) of any one of claims 1 to 7, wherein the cryogen expansion device (14) comprises a suitable heat exchanger, optionally configured to heat the cryogen using heat from one or more of ambient air, geothermal heat, industrial waste heat from a power plant, and waste heat from a manufacturing plant. (i) storing a cryogen in a cryogen storage facility (112), the cryogen storage facility (112) storing or configured to store the cryogen; (a) one or more primary cryogen storage tanks (32); and (b) at least one secondary cryogen storage tank (30); A process comprising: (ii) expanding the stored cryogen received from the cryogen storage facility (112); (iii) generating electrical energy by using the expanded cryogen to operate a suitable energy generating device (16); (iv) providing a superconducting device (18) within the cryogen storage facility (112); (v) cooling the superconducting device (18) with a cryogen stored in the cryogen storage facility (112); and (vi) providing, as necessary, a suitable pump (P) and a suitable valve (V1) in the fluid flow path between the one or more primary cryogen storage tanks (32) and the at least one secondary cryogen storage tank (30) for controlling the flow of cryogen from the primary tank (32) to the secondary tank (30); Including, the secondary cryogen storage tank (30) is a suitably insulated cryogen storage tank and contains at least the superconducting device (18) therein; A method for operating a cryogenic energy storage system (10).

10. 10. The method of claim 9, wherein the superconducting device (18) is selected from the group comprising a superconducting magnetic energy storage (SMES) device, a superconducting transformer (ST), a superconducting electronic device, and a superconducting fault current limiter (SFCL).

11. A method as described in any one of claims 9 or 10, wherein the method includes the step of providing a suitable temperature reduction assembly configured to reduce the temperature of the cryogen in the at least one secondary cryogen storage tank (30), and optionally the temperature reduction assembly further comprises a vacuum pump configured to reduce the vapor pressure in the secondary storage tank, and wherein operation of the vacuum pump, when in use, reduces the temperature of the cryogen in the secondary cryogen storage tank.

12. measuring one or more parameters associated with the cryogen storage tank (30) and / or associated with the cryogen stored in the cryogen storage tank (30); transmitting the measured parameters to a suitable processor (20) communicatively coupled to a suitable storage device (22); and activating an appropriate alarm protocol in response to determining one or more measured parameters as unacceptable.

12. The method of claim 11, comprising:

13. 13. The method of claim 12, further comprising the steps of: transferring cryogen from the primary cryogen storage tank (32) to the secondary cryogen storage tank (30) in response to detecting that the level of cryogen in the secondary cryogen storage tank (30) is below a predetermined threshold; and / or transferring cryogen from the secondary cryogen tank (30) to the primary cryogen tank (32) up to a minimum volume of cryogen required in the secondary tank for the superconducting device.

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