Device for coupling an energy store in the form of liquefied or compressed gas to a client having a need for cold

Abstract

The device (50) for coupling an energy reservoir (52) in the form of liquefied or compressed gas to a client (53) comprises: - at least one gas compressor (51, 54) configured to supply compressed gas to a fluid storage system (52, 67, 69) comprising the energy reservoir, - an interface thermal energy store (56) positioned at the inlet of the fluid storage system and at the outlet of the fluid storage system and configured to cool the gas at the inlet of the fluid storage system and to heat the gas at the outlet of the fluid storage system, - at least one expansion valve (58, 59) coupled to an electricity generator and configured to receive compressed gas from this thermal energy store, and - a pipe for transporting the expanded gas, leaving at least one expansion valve (59), to the client.

Description

[0001] DESCRIPTION

[0002] DEVICE FOR COUPLING ENERGY STORAGE IN THE FORM OF LIQUEFIED OR COMPRESSED GAS WITH A CUSTOMER HAVING A REFRIGERATION NEED

[0003] TECHNICAL FIELD OF THE INVENTION

[0004] The present invention relates to a method and a device for coupling energy storage in the form of liquefied or compressed gas with a customer requiring cooling, typically a data center. It applies, in particular, to the coupling of energy storage in the form of air or liquefied nitrogen with a data center.

[0005] STATE OF THE ART

[0006] Climate change is a major issue, and all sectors are being asked to reduce their carbon dioxide (CO2) emissions. Power generators must be "decarbonized" to meet the decarbonization requirements of companies offering or using cloud storage, which involves multiple data centers that must simultaneously consume electricity to operate and cool server networks.

[0007] Customers requiring electricity and cooling are provided with generator sets ("GE"). In the event of a power outage, these generators are used to generate electricity and, in particular, to operate cooling units to cool data center servers.

[0008] To replace generators using petroleum derivatives, several solutions are being studied, including their replacement by natural gas, biomethane, hydrotreated vegetable oils ("HVO"), hydrogen, syngas, and batteries. However, these solutions are still under study and are not yet commercially available.

[0009] When generators are used as backup units for industries with critical needs for both electricity and cooling, existing solutions require operating the cooling units in their facilities, which increases the need for backup electricity (hence oversizing the facilities) and increases the risk of overheating of the customer's facilities if the cooling unit has difficulty starting. In addition, these generators must be tested regularly (for example, once a month for approximately 45 minutes). These tests consume energy unnecessarily and generate local CO2 and air pollutant emissions.

[0010] Liquid Air Energy Storage (LAES) devices are known, which store energy during periods of abundant production or low electricity prices and release electricity during periods of shortage or high electricity prices. However, these systems have limited energy efficiency. An example of such a device is international patent application WO2014 / 070568. SUMMARY OF THE INVENTION

[0011] The present invention aims to remedy all or part of these drawbacks.

[0012] To this end, the device that is the subject of the invention comprises thermal energy storage units to enable electricity to be stored at certain times and then released at another time, while continuously providing cold. This device also enables electrical energy and cold to be supplied to the customer when the supply of electricity from the electricity network is too expensive, which constitutes an arbitration, or faulty, which constitutes a backup operation. To obtain cold, the customer is integrated into the liquefaction process in the same way as the other elements of the installation with their own operating constraints. These constraints are taken into account in the design of the thermal energy storage, making it possible to use and optimize the intrinsic losses of each element.This results in better use of thermal flows within the device, particularly with regard to thermal discharges into the environment.

[0013] Initial estimates show that the device subject to the invention has an energy efficiency of 64%, higher than that of a liquefied air energy storage (LAES) device alone. This device also makes it possible to guarantee backup operation of the installation by ensuring cogeneration of cold and electricity. If backup operation is not used, the energy efficiency of the installation can reach and exceed 75% thanks to the optimization of the turbines and the recovery of heat from the thermal storage.

[0014] The invention offers flexibility of choice between using electricity from the network or using stored electricity (for example, by a LAES) to supply a customer needing electricity and cooling, for example to respond to problems of power cuts, high price of electricity or origin of electricity (decarbonized or not).

[0015] The principle of the solution includes, in embodiments:

[0016] - to recover the heat (and store it) from the compression of the air during the compression phase, or even liquefaction,

[0017] - to recover cold from non-liquefied air in the tank during a liquefaction phase, to provide cold to the customer,

[0018] - to supply electricity and cooling to the customer during expansion between two turbines or after the last turbine,

[0019] - to provide cold to the customer when the device switches to cold group mode during pause or shutdown phases of the device's storage function when the power supply is provided by the network.

[0020] Furthermore, thanks to this integration, the customer moves from a consumer operation to a producer-consumer operation (in English "producer-consumer", abbreviated to "prosumer"). It could even be possible to return part of the stored electricity to the electricity grid. OBJECT OF THE INVENTION

[0021] The present invention aims to solve all or part of the technical problems of the prior art.

[0022] To this end, the present invention relates to a device for coupling an energy reservoir in the form of liquefied or compressed gas with a customer having a need for cold, which comprises at least one gas compressor configured to supply compressed gas to a fluid storage system comprising the energy reservoir, characterized in that it further comprises:

[0023] - an interface thermal energy storage positioned at the inlet of the fluid storage system and at the outlet of the fluid storage system, configured to cool the gas at the inlet of the fluid storage system and heat the gas at the outlet of the fluid storage system,

[0024] - at least one regulator coupled to an electricity generator, configured to receive compressed gas from this thermal energy storage, and

[0025] - a pipeline for transporting the expanded gas leaving at least one said regulator to the customer.

[0026] This interface thermal energy storage (56 in the figures) is charged with thermal energy during the air compression and liquid air storage phase, and provides heat during the air expansion and electricity supply phase and during the backup phase.

[0027] In embodiments, the energy reservoir stores the energy in the form of liquefied gas, the fluid storage system comprising an expansion system and a liquid separator, the device further comprising a peripheral thermal energy storage configured to reheat the residual gas leaving the liquid separator and a pipeline for transporting the reheated residual gas to an inlet of a said compressor.

[0028] This peripheral thermal energy storage (57 in the figures) is charged with frigories during the air compression and liquid air storage phase, and returns these frigories to the customer during the air expansion and electricity supply phase.

[0029] In embodiments, the device comprises, in a configuration for expanding fluid from the fluid storage system and supplying electricity to the customer, a gas circulation loop comprising said peripheral thermal energy storage having heated the residual gas leaving the liquid separator and the customer.

[0030] Peripheral thermal energy storage thus enables additional cooling of the customer.

[0031] In embodiments, the device comprises at least one upstream gas compressor and one downstream gas compressor configured to supply compressed gas to a fluid storage system and an intermediate thermal energy reservoir cooling the compressed gas from an upstream compressor before it enters the downstream compressor.

[0032] This intermediate thermal energy reservoir (55 in the figures) is charged with thermal energy during the air compression and liquid air storage phase, and provides heat to at least one expander coupled to an electricity generator, configured to receive compressed gas from this thermal energy storage, during the air expansion and electricity supply phase and during the backup phase.

[0033] In embodiments, the device comprises at least two expanders and, in a configuration for expanding fluid from the fluid storage system and supplying electricity to the customer, a gas circulation loop comprising said intermediate thermal energy storage and the customer, this intermediate thermal energy storage receiving expanded air from at least one expander.

[0034] Thus, the intermediate thermal energy storage receives frigories from the expanded air and supplies them to the customer.

[0035] In embodiments, the device comprises, when in a configuration in which no compressed gas enters or leaves the fluid storage system, an upstream gas circulation loop successively comprising the upstream compressor, a said expander and the client.

[0036] Thus, dry air leaving the customer is compressed by the upstream compressor, which reduces, in the case of a semi-open loop, or even eliminates, in the case of a closed loop, the need to dry the air reaching the upstream compressor or coming from it.

[0037] In embodiments, the device further comprises a gas transport pipeline from a customer outlet to the upstream compressor inlet, said upstream loop being, when in a configuration in which no compressed gas enters or leaves the fluid storage system, a closed loop.

[0038] Thus, in pause phases, only dry air leaving the customer is compressed by the upstream compressor, which avoids the need to dry the air reaching or coming from the upstream compressor.

[0039] In embodiments, the device comprises, when in a configuration in which no compressed gas enters or leaves the fluid storage system, a closed gas circulation loop successively comprising a said compressor, said interface thermal energy storage, a said expander and the client.

[0040] The expander thus provides colds to the customer, during a pause phase, while the heat generated by the compression of the gas carried out by the compressor is stored in the thermal energy storage.

[0041] In embodiments, the device comprises, when in a configuration in which no compressed gas enters or leaves the fluid storage system, a closed gas circulation loop successively comprising a said compressor, a said expander, an expansion system and the customer.

[0042] The expander thus provides frigories to the customer, during a pause phase, while, preferably, the heat generated by the compression of the gas carried out by the compressor is evacuated via a heat exchanger. In embodiments, at least one said loop comprising a compressor and an expander comprises, downstream of the compressor and upstream of the expander, a heat exchanger with a thermal source.

[0043] The compressed gas is thus cooled before being expanded and then used to cool the customer. It should be noted that the thermal source with which the heat exchange of the compressed gas is carried out can be fatal, hot or cold, or an air dryer (mechanical, chemical or membrane, for example).

[0044] In embodiments, the device comprises, at the outlet of a compressor, a multi-way valve for sharing, when the device is in a fluid storage configuration, the flow of air compressed by this compressor into a part going towards the fluid storage and a part going into a loop comprising said compressor and an expander.

[0045] Thus, part of the compressed gas is used to cool, after expansion and, possibly, heat exchange, the customer and part of the compressed gas is used to store colds in the form of liquefied or compressed gas.

[0046] BRIEF DESCRIPTION OF THE FIGURES

[0047] Other advantages, aims and characteristics of the present invention will emerge from the description which follows, given for explanatory and in no way limiting purposes with regard to the appended drawings, in which:

[0048] Figure 1 schematically represents a configuration of installation of the device which is the subject of the invention with respect to a customer and electricity and refrigeration distribution networks,

[0049] Figure 2 represents, schematically and structurally, a first particular embodiment of the device which is the subject of the invention,

[0050] Figure 3 schematically represents the device illustrated in Figure 2, in a phase of air compression and liquid air storage,

[0051] Figure 4 schematically represents the device illustrated in Figure 2, in a phase of air expansion and electricity supply,

[0052] Figure 5 schematically represents the device illustrated in Figure 2, in a pause phase,

[0053] Figure 6 schematically represents the device illustrated in Figure 2, in a backup phase,

[0054] Figure 7 represents, schematically and structurally, a second particular embodiment of the device which is the subject of the invention,

[0055] Figure 8 schematically represents the device illustrated in Figure 7, in a phase of air compression and liquid air storage,

[0056] Figure 9 represents, schematically, the device illustrated in Figure 7, in an air expansion and electricity supply phase, Figure 10 represents, schematically, the device illustrated in Figure 7, in a pause phase,

[0057] Figure 11 schematically represents the device illustrated in Figure 7, in a backup phase,

[0058] Figure 12 represents, schematically and structurally, a third particular embodiment of the device which is the subject of the invention,

[0059] Figure 13 schematically represents the device illustrated in Figure 12, in a phase of air compression and liquid air storage,

[0060] Figure 14 schematically represents the device illustrated in Figure 12, in a phase of air expansion and electricity supply,

[0061] Figure 15 schematically represents the device illustrated in Figure 12, in a pause phase, and

[0062] Figure 16 schematically represents the device illustrated in Figure 12, in a backup phase.

[0063] DESCRIPTION OF EMBODIMENTS

[0064] This description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

[0065] Please note that the figures are not to scale.

[0066] As understood from the present description, various inventive concepts may be implemented by one or more methods or devices described below, several examples of which are provided herein. The actions or steps performed in carrying out the method or device may be ordered in any suitable manner. Accordingly, it is possible to construct embodiments in which the actions or steps are performed in a different order than illustrated, which may include performing certain acts simultaneously, even if they are presented as sequential acts in the illustrated embodiments.

[0067] The expression "and / or", as used herein, shall be understood to mean "either or both" of the elements so conjoined, i.e., elements which are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and / or" shall be interpreted in the same way, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present, other than the elements specifically identified by the "and / or" clause, whether or not they are related to those specifically identified elements.Thus, by way of non-limiting example, a reference to "A and / or B", when used in conjunction with open language such as "comprising" may refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0068] As used herein, the term "at least one," in reference to a list of one or more elements, is to be understood to mean at least one element selected from one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements and not excluding any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than the specifically identified elements in the list of elements to which the term "at least one" refers, whether or not related to those specifically identified elements.Thus, by way of non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B", or, equivalently, "at least one of A and / or B") may refer, in one embodiment, to at least one, optionally including more than one, A, without B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, without A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0069] In the description below, all transitional expressions such as "comprising", "including", "bearing", "having", "containing", "involving", "holding", "consisting of", and the like, are to be understood as open, i.e., as meaning including, but not limited to. Only the transitional expressions "consisting of" and "consisting essentially of" are to be understood as closed or semi-closed transitional expressions, respectively.

[0070] In the description, the term "fluid" refers to a fluid, such as air, nitrogen or a mixture of ambient air and nitrogen, which takes, depending on the operating phases of the device which is the subject of the invention, a cryogenic liquid form or a gaseous form.

[0071] In all figures, the crossings of lines representing pipes, which do not have a valve, do not include any connection between these pipes.

[0072] FIRST EMBODIMENT (FIGURES 2 TO 6)

[0073] Figure 1 schematically represents a configuration 30 for installing a device 34 that is the subject of the invention with respect to a client consisting of a data center 33. The device 34 supplies electricity and cold to the data center 33. Optionally, an electricity network 31 supplies electricity to the data center 33. Optionally, the device 34 supplies electricity to the electricity network 31 and heat to a local heating network 32, for example a district heating network.

[0074] Part 35, comprising the device 34 and the data center 33, is detailed, according to different embodiments of the invention, with reference to figures 2 to 16. Figure 2 presents a structural diagram of coupling a customer having a need for cold 53, for example, as described with reference to the figures, a data center, to the device 50 comprising a liquid air energy storage system (LAES).

[0075] The pipes illustrated in Figure 2 are shown in Figures 3 to 6 when they are traversed by a fluid, in different phases of operation of the device 50:

[0076] - a phase of air compression and liquid air storage is described with regard to figure 3,>

[0077] - an air expansion and electricity supply phase is described with regard to figure 4,

[0078] - a pause phase is described with regard to figure 5, and

[0079] - a backup phase is described in relation to figure 6.

[0080] At different stages of this operation, thermal energy storage (or "TES") 55, 56 and 57 make it possible to store and restore heat and cold from the compression phase to the expansion phase and vice versa. The pipes shown in Figures 3 and 5 couple compressors and expansion valves to produce cold in order to cool the data center 53 during the compression (Figure 3) and pause (Figure 5) phases. This air cooler coupling makes it possible to avoid the use of a dedicated cooling system, for example an air conditioning system.

[0081] In Figure 2, we see an upstream compressor 51 connected to a gaseous fluid inlet. The outlet of this upstream compressor 51 is connected to a multi-way valve 64. One of the other ways of this valve 64 is connected to an inlet of a first heat exchanger 62 with a thermal source, for example the environment (in English intercooler), for example through a cooling tower. More generally, the thermal source with which the heat exchange of the compressed gas is carried out can be fatal, hot or cold, or an air dryer (mechanical, chemical or membrane, for example).

[0082] This first heat exchanger 62 is connected, at its output, to the input of a first expander 59, for example a turbine associated with an electricity generator. The output of the first expander 59 is connected to the data center 53. Another channel of the valve 64 is connected to an input of a first thermal energy storage 55, one output of which is connected to the input of the first expander 59. Another input of the thermal energy storage 55 is connected to the data center 53. Another output of the thermal energy storage 55 is also connected to the data center 53.

[0083] Yet another output of the thermal energy storage 55 is connected to a multi-way valve 65, another input of which is connected to the data center 53, another input is connected to a third thermal energy storage 57 and the output is connected to a downstream compressor 54. The output of the downstream compressor 54 is connected to a multi-way valve 66, one output of which is connected to a second thermal energy storage 56 and another output is connected to an inlet of a second heat exchanger 63 with a fatal thermal source, for example the environment (in English intercooler), for example through a cooling tower. More generally, the thermal source with which the heat exchange of the compressed gas is carried out may be fatal, hot or cold, or an air dryer (mechanical, chemical or membrane, for example).

[0084] The output of the second heat exchanger 63 is connected to an inlet of a second expander 58, for example a turbine associated with an electricity generator. The output of the second expander 58 is connected, on the one hand, to an inlet of the thermal energy storage 55 and, on the other hand, to an inlet of a first expansion system (for example, a Joule-Thomson valve, a cryogenic air turbine, etc.) 68. The output of the first expansion system is connected to the data center 53.

[0085] The second thermal energy storage 56 has an outlet connected to the inlet of the second expander 58 and an outlet connected to a second expansion system 67. The outlet of the second expansion system (e.g., a Joule-Thomson valve, a cryogenic air turbine, etc.) 67 is connected to a liquid separator 69, the liquid outlet of which is connected to a liquid fluid storage tank 52. The expansion system 67, the fluid separator 69, and the tank 52 together constitute a fluid storage system. In embodiments in which compressed gas, rather than cryogenic liquefied gas, is stored in the tank 52, it constitutes, by itself, a fluid storage system. The tank 52 is, moreover, connected to a cryogenic pump 70, the outlet of which is connected to the second thermal energy storage 56.The gas outlet of the separator 69 is connected to an inlet of the third thermal energy storage 57, another inlet and an outlet of which are connected to the data center 53. Finally, the data center 53 has an outlet 71 connected to the upstream compressor 51 during certain operating phases, as described below with reference to Figures 3 and 5.

[0086] A control unit 75, for example a computer or a server, controls the operation and state of the various elements shown in Figure 2 to implement the operating phases of the device illustrated in Figures 3 to 6. The solenoid valves, at the input and / or output of these elements, are not shown in Figures 2 to 6, for the sake of clarity. The connections between this control unit 75 and these various elements and solenoid valves are not shown in Figures 2 to 6, for the sake of clarity. Similarly, the power supplies of these various elements and solenoid valves and of the control unit 75 are not shown, for the sake of clarity of Figures 2 to 6.

[0087] The path of the fluid during each phase of operation of the device 50 is now described with reference to figures 3 to 6.

[0088] Figure 3 shows the elements and the different paths necessary for the compression phase. This compression phase uses the two compressors 51 and 54, the three thermal energy storages 55, 56 and 57, the expander 58, the expander 59, and the liquid fluid reservoir 52. The path of the fluid to be liquefied passes successively through the upstream compressor 51, the multi-way valve 64, the thermal energy storage 55, the multi-way valve 65, the downstream compressor 54, the multi-way valve 66, the second thermal energy storage 56, the second expansion system 67, the separator 69 and the liquefied fluid reservoir 52. Simultaneously, the gaseous fluid dedicated to cooling the data center 53 passes through two paths. On the one hand, a portion of the fluid compressed by the upstream compressor 51 leaves the multi-way valve 64 and successively passes through the first heat exchanger 62 and the first expansion valve 59 before arriving at the data center 53.On the other hand, a portion of the fluid compressed by the downstream compressor 54 leaves the multi-way valve 66 and successively passes through the second heat exchanger 63, the second expansion valve 58 and the first expansion system 68 before arriving at the data center 53.

[0089] Furthermore, the gaseous fluid leaving the separator 69 passes through the third thermal energy storage 57 before reaching the multi-way valve 65. Cooling gas from the data center also exits towards the multi-way valve 65.

[0090] The phase of compression, storage of liquefied fluid and simultaneous cooling of the data center 53 is described below, with reference to Figure 3, in the case where the fluid is ambient air.

[0091] Ambient air is drawn in and compressed by the upstream compressor 51. This hot compressed air is divided into two streams through the multi-way valve 64. A portion of the hot compressed air is cooled and dried by the first heat exchanger 62. This dried cooled air is expanded by the first expansion valve 59 to provide electricity and cold air. This cold air is heated by the data center 53 before being released into the atmosphere, at outlet 71. Thus, the data center is partially cooled. The other portion of the hot compressed air at the outlet of the multi-way valve 64 is cooled by the first thermal energy storage 55. Conversely, the first thermal energy storage 55 receives heat from this air stream.

[0092] This cooled compressed air is then mixed with recycled air in the multi-way valve 65. This air mixture is then compressed by the downstream compressor 54. This hot compressed air is split into two air streams by the multi-way valve 66. A first air stream is cooled and dried by the second heat exchanger 63 and is then expanded through the second expansion valve 58 to produce cold and electricity. This partially expanded air is further expanded and cooled by the first expansion system 68 to reach the inlet pressure of the downstream compressor 54. However, before reaching this downstream compressor 54, this cold air is heated by the data center 53 and is then mixed with the main compressed air stream in the multi-way valve 65.

[0093] It is noted that, by heating the expanded air coming from the first expansion system 68, the data center 53 is cooled, which is the objective of this air circulation loop.

[0094] A second air flow exiting the multi-way valve 66 is cooled by the second thermal energy storage 56, which, in exchange, stores heat for use during the air expansion phase (Figure 4). This cooled air is liquefied by the second expansion system 67 and then stored in the liquid air tank 52. The non-liquefied air separated by the separator 69 is heated by the third thermal energy storage 57, which, in exchange, stores frigories to cool the data center, and then mixed with the main compressed air flow in the multi-way valve 65. It is noted that the recovery of the air at the outlet of 71 is possible for the compression phase illustrated in Figure 3, the quantity of fresh air entering the device 50 being equal to the flow rate required by the multi-way valve 65 and corresponding to the air liquefaction rate. We thus have a "semi-open" loop illustrated by the connection in broken lines.

[0095] The phase of expansion of the fluid stored in the liquid air tank 52, of production of electricity and of simultaneous cooling of the data center 53 is described below, with reference to figure 4, in the case where the fluid is ambient air.

[0096] The main elements used during this expansion phase are the liquid air tank 52, the cryogenic pump 70, the two expanders 58 and 59 and the three thermal energy storages 55, 56 and 57, in order to store frigories from the liquid air and its expansion. Simultaneously, the data center 53 is cooled.

[0097] The liquid air stored in the tank 52 is pumped by the cryogenic pump 70. This compressed liquid air is then evaporated and heated by the second thermal energy storage 56. This thermal energy storage 56 thus stores cold for use during the compression phase (figure 3). This heated compressed air is partially expanded by the second expander

[0098] 58 to produce electricity. This cold air is then heated through the first thermal energy storage 55 and then expanded by the first expansion valve 59 to produce electricity. The cold air leaving the first expansion valve 59 is conveyed to the data center 53 to cool it.

[0099] If the frigories provided by this air are not sufficient to meet the cooling needs of the data center 53, additional cooling comes from the first thermal energy storage 55. Finally, additional cooling is provided by the third thermal energy storage 57, to meet the cooling needs of the data center 53.

[0100] The pause phase (without charging or discharging the fluid reservoir 52), electricity production and cooling of the data center 53 is described below, with reference to FIG. 5, in the case where the fluid is ambient air.

[0101] Two independent air circulation loops are implemented to form a cooler depending on the available equipment: a first loop is composed of the upstream compressor 51, the first heat exchanger 62 and the first expansion valve 59. A second loop is composed of the downstream compressor 54, the second heat exchanger 63 and the second expansion valve 58.

[0102] During this pause phase, the two loops operate as follows. Ambient air is drawn in and compressed by the upstream compressor 51. The compressed hot air is cooled and dried by the first heat exchanger 62. This cooled air is then expanded by the first expansion valve

[0103] 59 to provide electricity and cooling. The cold air then cools the data center 53 and is therefore heated by this data center 53. The second loop is a closed loop. The compressed air from the data center 53 is sucked in and compressed by the downstream compressor 54. This hot compressed air is cooled by the second heat exchanger 63. Then, this cooled air is expanded by the second expansion valve 58 to provide electricity and cooling. Since the air is not expanded to the nominal inlet pressure level of the downstream compressor 54, it is expanded by the first expansion system 68 to this nominal pressure. This cold air then cools the data center 53 and is therefore heated by this data center 53, before returning to the inlet of the downstream compressor 54. Note that the compressors 51 and 54 operate at partial load.It is recalled here that compressors are defined with an optimal operating point (flow rate required when the compressor operates at 100%) and a minimum technical point (a minimum flow rate necessary to achieve the compression of the fluid to the installation pressure). Between these two points, the compressor operates at partial load.

[0104] Alternatively, the first loop is a closed loop by connecting the outlet 71 of the data center 53 to the inlet of the upstream compressor 51. This variant, shown in broken lines in Figure 5, has the advantage that the drying of the air, which consumes energy, is eliminated. Unlike the semi-open loop of Figure 3, the loop is closed in the pause phase illustrated in Figure 5, and carries dry air. For the implementation of this variant, a dry air reservoir (not shown) of the volume of the closed loop can be added to the first loop, between the outlet 71 and the upstream compressor 51.

[0105] The backup phase, with discharge of the liquid air tank 52, production of electricity and cooling of the data center 53 is described below, with reference to Figure 6, in the case where the fluid is ambient air.

[0106] The elements implemented for this backup phase are the liquid air tank 52, the cryogenic pump 70, the second thermal energy storage 56, the pressure reducers 58 and 59 and the first thermal energy storage 55.

[0107] During a power outage, liquid air is removed from the liquid air reservoir 52 and compressed by the cryogenic pump 70. This compressed liquid air is then evaporated through the second thermal energy storage 56 and then expanded by the second expansion valve 58 to produce electricity. This expanded air is reheated by the first thermal energy storage 55 and expanded by the first expansion valve 59 to produce electricity. The data center 53 is cooled in the manner described with respect to FIG. 4, with or without the additional cooling provided by the third thermal energy storage 57.

[0108] SECOND EMBODIMENT (FIGURES 7 TO 11)

[0109] Figures 7 to 11 show a second embodiment of a device 80 which is the subject of the invention. All the elements of the device 50 are found in the device 80. The operating phases illustrated in Figures 8 to 11 correspond, respectively, to the operating phases illustrated in Figures 3 to 6.

[0110] In this second embodiment, a third expander 82 is located upstream of the first expander 59, on an additional pipe going from an outlet of the first thermal energy storage 55 to the first expander 59. In addition, a fourth expander 81 is located downstream of the second expander 58 on an additional pipe going from the second expander 58 to the first thermal energy storage 55. As illustrated in FIGS. 8 to 11, these expanders 81 and 82 are only used in the phase of expansion, discharge of the liquid air tank 52, production of electricity and simultaneous cooling of the data center 53 (FIG. 9). In the other phases (FIGS. 8, 10 and 11), the expanders 81 and 82 are not crossed by any fluid flow.In the air compression and liquid air storage phase (Figure 8), the outlet of the expander 58 is connected, via the first expansion system 68, to the data center 53 and the outlet of the expander 59 is connected to this data center 53. In the pause phase (Figure 10), the expander 58 is connected, via the first expansion system 68, to the data center 53 and the expander 59 receives compressed air from the heat exchanger 62 and is connected to this data center 53. In the backup phase (Figure 11), the expander 58 receives air from the second thermal energy storage 56 and, after expansion, supplies it, on the one hand, to the data center 53 via the first expansion system 68, and, on the other hand, to the first thermal energy storage 55. Furthermore, the expander 59 receives air from the first thermal energy storage 55 and, after expansion, supplies it to the data center 53.

[0111] It is noted that, in an air compression and liquid air storage phase illustrated in Figure 8, the air leaving the outlet 71 can be recovered to inject it into the upstream compressor 51 to form a semi-open loop, as explained with reference to Figure 3. Similarly, in the pause phase illustrated in Figure 10, a closed loop described with reference to Figure 5 can be set up. During the expansion phase, discharge of the liquid air tank 52, production of electricity and simultaneous cooling of the data center 53 (Figure 9), the third and fourth expanders, respectively 82 and 81, make it possible to produce more electricity.

[0112] THIRD EMBODIMENT (FIGURES 12 TO 16)

[0113] Figures 12 to 16 show a third embodiment of a device 90 which is the subject of the invention. All the elements of the device 50 are found in the device 90, with the exception of the heat exchangers 62 and 63. Figures 12 to 16 correspond, respectively, to Figures 2 to 6.

[0114] On the other hand, an additional regulator 92 (called “fifth” so as not to confuse it with the third regulator 82 of the second embodiment although the latter is absent from the third embodiment) has its input connected to an output of the first thermal energy storage 55 and its output connected to an input of the first thermal energy storage 55. In addition, a sixth regulator 91 has its input connected to an output of the second thermal energy storage 56 and its output connected to an input of the first thermal energy storage 55.

[0115] In this embodiment, it is assumed that the storage makes it possible to absorb all the heat from the compression linked to the liquefaction cascade. More precisely, the first thermal energy storage 55 is composed of several thermal storages and exchangers in order to store the heat of compression (bypass, or bypass, with the multi-way valve 64 during compression) instead of ventilating this heat with the heat exchanger 62. The same applies to the second thermal energy storage 56. Thus, two additional expansion valves 91 and 92 are introduced in order to recover this heat in the form of electrical energy. As illustrated in figures 13 to 16, these expansion valves 91 and 92 are only used in the phase of expansion, discharge of the liquid air tank 52, production of electricity and simultaneous cooling of the data center 53 (figure 14).In the other phases (figures 13, 15 and 16), the regulators 91 and 92 are not crossed by any fluid flow. Only the differences between the operations of the devices 50 and 90 are described below.

[0116] During the air compression and liquid air storage phase, illustrated in Figure 13, and during the pause phase, illustrated in Figure 15, the inlet of the expander 59 is supplied by the first thermal energy storage 55 and the outlet of this expander 59 is connected to the data center 53. At the same time, the inlet of the expander 58 is supplied by the second thermal energy storage 56 and the outlet of the expander 58 is connected, via the first expansion system 68, to the data center 53.

[0117] During the phase of expansion, discharge of the liquid air tank 52, production of electricity and simultaneous cooling of the data center 53 (figure 14), the fifth expander 92 receives air from the first thermal energy storage 55 and returns the expanded air to the first thermal energy storage means 55. The sixth expander 91 receives air from the second thermal energy storage 56 and sends the expanded air to the first thermal energy storage means 55. The second expander 58 receives air from the second thermal energy storage 56 and returns the expanded air to the second thermal energy storage means 56. This configuration makes it possible to produce more electricity than the equivalent configuration of the first embodiment (figure 4).

[0118] During the backup phase (figure 16), the expander 58 receives air from the second thermal energy storage 56 and, after expansion, supplies it to the first thermal energy storage 55.

[0119] VARIANTS

[0120] The thermal energy storages 55, 56 and 57, and particularly the thermal energy storage 56 for interface with the fluid storage system comprising the reservoir 52, can be composed of two parts:

[0121] - a first part to store the heat of the compressed air, and

[0122] - a second part to store the cold of the stored fluid (in liquid or gaseous form).

[0123] The fluid can be air, nitrogen, carbon dioxide, natural gas, for example. In the case where the fluid is not compressed ambient air, the device includes a low-pressure reservoir of this fluid (not shown).

[0124] Furthermore, the device which is the subject of the invention may include buffer tanks on the loops illustrated in figures 5, 10 and 15, to regulate the flow rate. These buffer tanks have three functions:

[0125] - regulate the flow rate, particularly when the compressors do not operate at the same flow rate, for example in the case of semi-open loops,

[0126] - allow a network to be filled and an open-loop system to be transformed into a closed-loop system, for example in the case of cold production during installation breaks, and - allow the device to be started while the rotating machines are synchronized.

[0127] Heat exchangers 62 and 63 can be replaced by heat recovery exchangers for other uses, for example space heating.

[0128] Liquid storage (e.g., LAES, Liquid Air Energy Storage, if the fluid is air or nitrogen) can be replaced by gaseous storage of cold fluid under pressure, for example Compressed Air Energy Storage (CAES).

[0129] Each thermal energy storage 55, 56 and 57:

[0130] - may or may not include a heat exchanger,

[0131] - can be composed of several thermal energy storage entities (identical or not), each including or not a heat exchanger.

[0132] Each regulator 58, 59, 81, 82, 91, 92 shown in Figures 2 to 16 can be replaced by a succession of regulators.

[0133] The device which is the subject of the invention may further comprise an exchanger (or any other system making it possible to supply heat, for example thermal solar panels, photovoltaic panels coupled with an electrical resistance, a fatal thermal source coming from the data center 53, or not) between the expanders 58 and 59 and / or between the expanders 81 and 82.

[0134] EXAMPLES OF SPECIFICATIONS OF THE ELEMENTS OF THE DEVICE OBJECT OF THE INVENTION

[0135] Expansion turbines, for example, withstand low temperatures of 0°C in the backup phase (figures 6, 11 and 16) and -50°C in the expansion phase (figures 4, 9 and 14).

[0136] For example, the mass flow rate of the regulators is 8 kg. s -1 , which means that the liquefaction ratio must also be in agreement to produce 8 kg. s -1of liquefied fluid. We recall here that the liquefaction ratio is the vapor or liquid content in the two-phase case. We are interested here in the liquid content, that is to say the part which is stored. Depending on the thermodynamic conditions of the fluid, we obtain contents of 30% to 90%. Thanks to the second means of thermal energy storage 56, we could reach a content of 70%, i.e. a mass flow rate of the expanders equal to 8 kg. s -1 . Thus, the mass flow rate of the downstream compressor 54 is 11.5 kg. s -1 . So there are 3.5 kg. s -1 of non-liquefied nitrogen which are recycled. The upstream compressor 51 must therefore have a minimum flow rate of 8 kg. -1 The pressure of the cryogenic tanks is set at 10 bar. This pressure also serves as a thermodynamic condition, with the temperature of -150°C to obtain a liquid content of at least 70%, for example 85% in the simulation below.

[0137] SIMULATION RESULTS

[0138] The following section presents the schematic diagram and simulation results of a preliminary configuration compressing ambient air. This configuration provides:

[0139] - cooling of a customer 24 hours a day; - electricity supplies, for example for peak shaving and time shifting of electricity consumption, without interruption of cooling; and

[0140] - backup for as long as necessary, since the device can be powered by an external source of cryogenic liquid, for example by truck or pipeline transport.

[0141] Furthermore, this configuration is very flexible and can be easily adapted to different customers. Electrical power is provided by the expansion valves. Cooling is provided by the compressor and expansion valve pair and defined by the non-liquefied air ratio. This ratio can easily be defined by a Mollier diagram and its two-phase curve. Based on commercial components, initial simulations were carried out and an energy efficiency range was estimated between 45% and 65%.

[0142] Table 14, Table 15 and Table 16 show the fluid condition (pressure, temperature and mass flow rate) at the inlet and outlet of each main equipment of a particular embodiment of a device that is the subject of the invention. As can be seen from these tables, the energy required by the customer's cooling system is reached 24 hours a day.

[0143] For example, a customer may have a permanent cooling requirement of 850 kW in order to maintain the operating conditions of its server rooms. During compression, we can see that part of the air mass flow is dedicated to cooling the customer while the other part of the air mass flow is dedicated to the liquefaction part. We can see from this design that the liquefaction is very good since it is between 70% and 90%, much higher than the ratios obtained by industrial air liquefaction installations. Indeed, with the example of air turbines using 8 kg. s -1 , the absorbed ambient air flow is between 11.5 kg. s -1 and 9 kg. s -1 depending on the liquid strength, i.e. between 3.5 kg. -1 and 1 kg. s -1 of non-liquefied air. Therefore, the main part of the compression mass flow rate is dedicated to customer cooling.

[0144] During the air expansion and electricity supply phase, electricity is produced by the expansion valve. In addition, these expansion valves also produce cold, which is used to cool the customer. However, as can be seen in Table 15, these expansion valves do not produce enough cold (between 600 and 700 kW of cold), which does not correspond to the 850 kW required to cool the customer. This gap is filled by the frigories of the non-liquefied refrigerated air that were stored in the thermal energy reservoir 57 during the compression phase and which are drawn from it during the air expansion and electricity supply phase. This amount of stored energy is variable, in this simulation, between 166 and 285 kWh, which is sufficient to fill the gap.

[0145] During the pause phase, the LAES is transformed into a chiller by coupling the compressors and expansion valves. As shown in Table 16, the energy produced by the device is sufficient to cool the customer.

[0146] The second point is the efficiency of the device since this ratio is commonly used for economic evaluation. There are different ways to evaluate the efficiency of a system: - Electrical efficiency: this efficiency only considers the electrical production over the electrical consumption. Therefore, all the energy recovered for the customer's cooling is not considered; and

[0147] - Energy efficiency: this efficiency takes into account the electricity production and the thermal energy used to cool the customer.

[0148] The definition of efficiency used is that of the following equation 1: q = (Energy produced in the form of electricity and in thermal form for the customer) / (Energy consumed by the compressors and pumps).

[0149] From Tables 14 and 15, the energy produced in the form of electricity and in the form of heat for the customer can be deduced by adding the electrical energy produced by the generators associated with the expanders, the customer's thermal consumption and the energy of the non-liquefied air. The consumption of the compressor and the cryogenic pump are added to evaluate the denominator. Thus, the LAES efficiency is between 45% and 54% for the extreme ranges of use.

[0150] Finally, Table 16 shows the consumption and production of the LAES when it behaves as a chiller. According to the equation above, the efficiency of this chiller is 25% to 30%. By averaging the hot temperature of the two compressors and averaging the cold temperature efficiencies for the customer, the average coefficient of performance (COP) of this chiller is 1.15 to 1.25. This value seems low in comparison with the specifications of chillers, in which the COP range is defined as 2 to 7. However, it is important to mention that these COPs are specified for "ideal" conditions and that the measured seasonal COPs are much lower, which is not the case for the device that is the subject of the invention.Furthermore, it is important to note that this device stores energy, which is something that a refrigeration unit cannot do without a battery or, more generally, without a storage system, such as thermal storage. Finally, the device that is the subject of the invention is capable of operating without electricity, which is not the case with refrigeration units.

[0151] Table 14 represents the energy consumption of each main equipment of the LAES installation during the compression phase.

[0152] [Table 14]

[0153] Table 15 represents the energy consumption of each main component of the LAES installation during the air expansion and electricity supply phase.

[0154] [Table 15]

[0155] Table 16 represents the energy consumption of each main component of the LAES installation during the pause phase.

[0156] [Table 16]

Claims

CLAIMS 1. Device (50, 80, 90) for coupling an energy reservoir (52) in the form of liquefied or compressed gas with a customer having a need for cold (53), which comprises at least one gas compressor (51, 54) configured to supply compressed gas to a fluid storage system (52, 67, 69) comprising the energy reservoir, characterized in that it further comprises: - an interface thermal energy storage (56) positioned at the inlet of the fluid storage system and at the outlet of the fluid storage system, configured to cool the gas at the inlet of the fluid storage system and heat the gas at the outlet of the fluid storage system, - at least one regulator (58, 59, 81, 82, 91, 92) coupled to an electricity generator, configured to receive compressed gas from this thermal energy storage, and - a pipeline for transporting the expanded gas leaving at least one said expander (59) to the customer, and in which the energy reservoir (52) stores the energy in the form of liquefied gas, the fluid storage system comprising an expansion system (67) and a liquid separator (69), the device further comprising a peripheral thermal energy storage (57) configured to heat the residual gas leaving the liquid separator and a pipeline for transporting the heated residual gas to an inlet of a said compressor (54).

2. Device (50, 80, 90) according to claim 1, which comprises, in a configuration for expanding fluid from the fluid storage system (52, 67, 69) and supplying electricity to the customer (53), a gas circulation loop comprising said peripheral thermal energy storage (57) having heated the residual gas leaving the liquid separator (69) and the customer.

3. Device (50, 80, 90) according to one of claims 1 or 2, which comprises at least one upstream gas compressor (51) and one downstream gas compressor (54) configured to supply compressed gas to a fluid storage system (52, 67, 69) and an intermediate thermal energy reservoir (55) cooling the compressed gas from an upstream compressor before it enters the downstream compressor.

4. Device (50, 80, 90) according to claim 3, which comprises at least two expanders and, in a configuration for expanding fluid from the fluid storage system (52, 67, 69) and supplying electricity to the customer (53), a gas circulation loop comprising said intermediate thermal energy storage (55) and the customer (53), this intermediate thermal energy storage receiving expanded air from at least one expander.

5. Device (50, 80, 90) according to one of claims 3 or 4, which comprises, when it is in a configuration in which no compressed gas enters or leaves the fluid storage system (52, 67, 69), an upstream gas circulation loop successively comprising the upstream compressor (51), a said expander (59) and the client (53).

6. Device (50, 80, 90) according to claim 7, which further comprises a gas transport pipeline from a customer outlet (53) to the inlet of the upstream compressor (51), said upstream loop being, when in a configuration in which no compressed gas enters or leaves the fluid storage system (52, 67, 69), a closed loop.

7. Device (90) according to one of claims 1 to 6, which comprises, when it is in a configuration in which no compressed gas enters or leaves the fluid storage system (52, 67, 69), a closed gas circulation loop successively comprising a said compressor (54), said interface thermal energy storage (56), a said expander (58) and the client (53).

8. Device (50, 80, 90) according to one of claims 1 to 7, which comprises, when it is in a configuration in which no compressed gas enters or leaves the fluid storage system (52, 67, 69), a closed gas circulation loop successively comprising a said compressor (54), a said expander (58), an expansion system (68) and the client (53).

9. Device (50, 80) according to one of claims 5 to 8, in which at least one said loop comprising a compressor (51, 54) and an expander (58, 59) comprises, downstream of the compressor and upstream of the expander, a heat exchanger (62, 63) with a thermal source.

10. Device (50, 80, 90) according to one of claims 5 to 9, which comprises, at the outlet of a compressor (54), a multi-way valve (66) for sharing, when the device is in a fluid storage configuration, the flow of air compressed by this compressor into a part going towards the fluid storage (52, 67, 69) and a part going into a loop comprising said compressor (54) and an expander (58).

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