Method and device for coupling an energy store in the form of liquefied gas with an industrial unit

Abstract

The device (50) for coupling at least one energy reservoir (52, 58) in the form of liquefied gas with a client (53) having a need for cold energy and heat comprises at least one compressor (51, 66) supplying compressed gas to a liquefied gas storage system (52, 58, 67, 69). This device comprises: - an interface thermal energy store (57) configured to, alternately, cool the gas at the inlet of the storage system and heat the gas at the outlet of an energy reservoir of the storage system, - at least one expansion device (59, 60) coupled to an electricity generator, receiving compressed gas coming from this interface thermal energy store, and - a pipe for transporting liquefied gas from an energy reservoir (58) to the client, and an intermediate thermal energy store (55), and means for directing flow depending on the need for cold energy or heat.

Description

[0001] METHOD AND DEVICE FOR COUPLING ENERGY STORAGE IN THE FORM OF LIQUEFIED GAS WITH AN INDUSTRIAL UNIT

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to a method and a device for coupling an energy storage in the form of liquefied gas with an industrial unit. It applies, in particular, to the coupling of an energy storage in the form of liquefied air or nitrogen with a frozen food production unit.

[0004] STATE OF THE ART

[0005] Some industrial plants require the use of cryogenic liquids, such as liquid nitrogen or carbon dioxide (CO2). There are electrically powered local cryogenic fluid production facilities. However, these local production facilities have limited overall efficiency.

[0006] Industrial units may also require cooling, for example for air conditioning, and heating, for example for cooking frozen food. However, heat pumps are currently limited to temperatures below 200°C, which is insufficient.

[0007] To provide simultaneous heating and cooling, heat pumps are coupled with chillers to provide a hot-cold cogeneration system. In this configuration, the heat rejected by the chiller serves as a cold source for the heat pump, thus coupling the two systems. However, these cogeneration systems do not meet the needs of industrial units, which often have a phase shift between heating and cooling consumption. This phase shift can be partially or completely offset by hot water storage. However, achieving very low temperatures often requires the use of ammonia, which presents industrial safety and health risks.

[0008] Liquid Air Energy Storage (LAES) systems are known, which store energy during periods of electricity abundance or low prices and release electricity during periods of electricity shortage or high prices. However, these systems are not efficient at providing both refrigeration and electricity.

[0009] We know of international application PCT WO 2014 / 070 568 and American patent application US 2015 / 113 940 which only provide for the supply of refrigerators to a customer.

[0010] SUMMARY OF THE INVENTION

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

[0012] To this end, the invention aims to produce and supply, locally and in a combined manner, electricity and liquefied gas, for example liquid nitrogen or liquid carbon dioxide CO2, for example for freezing units in the food industry. The device that is the subject of the invention has a great advantage in terms of flexibility with regard to the use of electricity: it is possible to reduce the consumption of electricity from the network (for reasons of high electricity cost or origin of the electricity - decarbonized or not) while continuing to produce and supply electricity to the customer and while continuing to supply liquefied gas produced when the device consumes electricity from the network.

[0013] Furthermore, part of the cold produced by the device which is the subject of the invention can be used for certain purposes, for example for cold stores, particularly in the food or pharmaceutical industries. Finally, the device which is the subject of the invention can also provide heat to the industrial unit, for example for cooking food.

[0014] The production of electricity from intermittent renewable energies and the need to move towards carbon-free industries are in fact highlighting an increasingly important need for electrification of industrial thermal uses. In this context, the device that is the subject of the invention can help reduce primary energy consumption.

[0015] Furthermore, thanks to this integration, the customer moves from operating as a consumer to operating as a producer-consumer (abbreviated as "prosumer").

[0016] SUBJECT OF THE INVENTION

[0017] The particular features of the various embodiments described above and / or shown in the figures are intended to be combined to constitute other embodiments of the present invention.

[0018] As understood from reading the above description, the present invention relates to a device for coupling at least one energy reservoir in the form of liquefied gas with a customer having a need for cooling. This device comprises at least one gas compressor configured to supply compressed gas to a liquefied gas storage system comprising each energy reservoir in the form of liquefied gas. This device further comprises:

[0019] - an interface thermal energy storage positioned at the inlet of the liquefied gas storage system and at the outlet of a reservoir of energy in the form of liquefied gas, configured to, alternately, cool the gas at the inlet of the liquefied gas storage system and heat the gas at the outlet of this reservoir of energy in the form of liquefied gas,

[0020] - at least one regulator coupled to an electricity generator, configured to receive compressed gas from this interface thermal energy storage,

[0021] - a pipeline for transporting liquefied gas from an energy reservoir in the form of liquefied gas to the customer, and

[0022] - a control unit for controlling the operation of each compressor, each expander and the interface thermal energy storage which further comprises an intermediate thermal energy storage, and at least two flow direction means controlled by the control unit: - a first flow direction means is connected at least to one heat input of the customer, to the intermediate thermal energy storage by a two-way connection,

[0023] - a second flow direction means is connected at least to a customer fluid outlet, to the intermediate thermal energy storage and to the interface thermal energy storage by two-way connections.

[0024] Thanks to these provisions, the device includes both the means of generating electricity after expansion of a liquefied gas and the means of supplying refrigeration to the customer, in the form of liquefied gas. Furthermore, the flow direction means allow, depending on the customer's needs, refrigeration and / or heat to be delivered to the customer.

[0025] In embodiments, the compressed gas is air, the liquefied gas storage system comprising:

[0026] - at least one energy reservoir in the form of liquefied air and

[0027] - at least one energy reservoir in the form of liquefied nitrogen supplied with nitrogen by a purifier.

[0028] The customer can thus be supplied with liquid food nitrogen stored in the tank, and implement known freezing processes.

[0029] In embodiments, the control unit is configured to control at least two phases of operation of the device, comprising at least:

[0030] - a charging phase, during which each compressor compresses gas and the interface thermal energy storage stores calories from the hot compressed gas and supplies each tank with energy in the form of liquefied gas, and

[0031] - a discharge phase, during which the interface thermal energy storage heats fluid from at least one energy reservoir in the form of liquefied gas and supplies gas to at least one regulator coupled to an electricity generator.

[0032] Thus, thanks to the interface thermal energy storage, the efficiency of the charging phase and that of the discharging phase are improved. The overall efficiency of the device is thus optimized.

[0033] In embodiments, the control unit is configured to control, during the discharge phase, the supply of liquefied gas to the customer from a liquefied gas energy reservoir.

[0034] The customer can thus be supplied with liquefied gas, for example liquid food nitrogen stored in the tank, and implement known freezing processes.

[0035] In embodiments, the control unit is configured so that:

[0036] - during the charging phase, the intermediate thermal energy storage is positioned downstream of at least one compressor and upstream of the interface thermal energy storage and stores calories from the hot compressed gas and supplies gas to the interface thermal energy storage and - during the discharging phase, the intermediate thermal energy storage heats gas from the customer and supplies heated gas to the customer.

[0037] Thus, the intermediate thermal energy storage receives calories from the compression of the gas, during the charging phase, and the customer receives calories from the intermediate thermal energy storage, during the discharging phase.

[0038] In embodiments, the control unit is configured such that, during the discharge phase, the intermediate thermal energy storage heats gas from the interface thermal energy storage and provides heated gas to at least one expander coupled to an electricity generator.

[0039] Thus, the intermediate thermal energy storage participates in the generation of electricity by the device, during the discharge phase, thanks to calories stored during the charge phase.

[0040] In embodiments, the device which is the subject of the invention comprises at least two compressors and, in addition, an upstream thermal energy storage, the control unit being configured so that: a) during the charging phase:

[0041] - the upstream thermal energy storage is positioned downstream of at least one compressor and upstream of at least one compressor and the intermediate thermal energy storage and stores calories from the compressed gas; and b) during the discharge phase:

[0042] - the gas leaving the interface thermal energy storage passes successively through the upstream thermal energy storage and through an expander (59) coupled with an electricity generator.

[0043] Thus, the upstream thermal energy storage participates in the generation of electricity by the device during the discharge phase, thanks to the storage of calories during the charge phase.

[0044] In embodiments, the device which is the subject of the invention comprises at least two expanders coupled to electricity generators and, in addition, downstream thermal energy storage, the control unit being configured so that: a) during the charging phase:

[0045] - the downstream thermal energy storage is positioned downstream of the intermediate thermal energy storage and upstream of the interface thermal energy storage and stores calories from the compressed gas; and b) during the discharge phase:

[0046] - the gas leaving a first expander coupled with an electricity generator passes through the downstream thermal energy storage and through a second expander coupled with an electricity generator. Thus, the downstream thermal energy storage participates in the generation of electricity by the device during the discharge phase, thanks to the storage of calories during the charge phase.

[0047] In embodiments, the control unit is configured to further control a pause phase during which gas exiting the customer is reheated by the downstream thermal energy storage before being supplied to the customer.

[0048] Thus, the downstream thermal energy storage participates in the supply of calories to the customer, during the pause phase, thanks to the storage of calories during the charging phase.

[0049] In embodiments, the device according to the invention further comprises a gas heater, the control unit being configured so that, during the pause phase, the gas leaving the customer heated by the downstream thermal energy storage is also heated by the gas heater before being supplied to the customer.

[0050] The gas heater increases the supply of calories to the customer during the break phase.

[0051] In embodiments, the device that is the subject of the invention further comprises a diversion thermal energy reservoir, the control unit being configured so that, during the charging phase, the diversion thermal energy reservoir receives gas compressed by a compressor, stores calories from this compressed gas and supplies this gas to an expander coupled to a generator.

[0052] Thus, the diversion thermal energy storage stores calories during the charging phase, these calories being available to be supplied to the customer during the discharging phase.

[0053] In embodiments, the control unit is configured so that, during the pause phase, a compressor compresses gas, the bypass thermal energy reservoir receives gas compressed by this compressor, stores calories from this compressed gas and supplies this gas to an expander coupled to a generator.

[0054] Thus, the diversion thermal energy storage stores calories during the pause phase, these calories being available to be supplied to the customer during the discharge phase.

[0055] In embodiments, the control unit is configured such that, during the discharge phase, the bypass thermal energy reservoir provides calories to the customer.

[0056] In embodiments, the device which is the subject of the invention further comprises a thermal energy storage of expanded gas positioned downstream of an expander, the control unit being configured so that this thermal energy storage absorbs frigories from the expanded gas leaving this expander, during the charging phase, and provides frigories to the customer, during the discharging phase.

[0057] In embodiments, the liquefied gas storage system comprises a separator for cryogenic liquid and non-liquefied gas, and, during the charging phase, the non-liquefied gas from this separator is supplied to a said compressor.

[0058] This results in recirculation of the non-liquefied gas, which has the advantage of being dry and cold. In some embodiments, the device of the invention further comprises a gas transport pipe from the customer to a compressor inlet.

[0059] This results in recirculation of the gas leaving the customer.

[0060] In embodiments, at least one flow directing means is a multi-way valve.

[0061] BRIEF DESCRIPTION OF THE FIGURES

[0062] 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:

[0063] - Figure 1 represents, in the form of a flowchart, the stages of a particular industrial process requiring electricity, heat and cold,

[0064] - figure 2 represents, schematically and structurally, a first particular embodiment of the device which is the subject of the invention in relation to a client,

[0065] - figure 3 represents, schematically, the device illustrated in figure 2, in a thermal energy storage charging phase,

[0066] - figure 4 represents, schematically, the device illustrated in figure 2, in a phase of discharging thermal energy storage,

[0067] - figure 5 represents, schematically, and structurally a variant of the device illustrated in figures 2 to 4,

[0068] - figure 6 represents, schematically, the device illustrated in figure 5, in a thermal energy storage charging phase,

[0069] - figure 7 represents, schematically, the device illustrated in figure 5, in a phase of discharging thermal energy storage,

[0070] - figure 8 represents, schematically, the device illustrated in figure 5, in a pause phase,

[0071] - figure 9 represents, schematically and structurally, a second particular embodiment of the device which is the subject of the invention,

[0072] - figure 10 represents, schematically, the device illustrated in figure 9, in a thermal energy storage charging phase,

[0073] - figure 11 represents, schematically, the device illustrated in figure 9, in a phase of discharging thermal energy storage,

[0074] - figure 12 represents, schematically, the device illustrated in figure 9, in a pause phase, and

[0075] - figure 13 represents, schematically and structurally, a variant of the first embodiment illustrated in figures 2 to 4. DETAILED DESCRIPTION

[0076] 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.

[0077] Please note that the figures are not to scale.

[0078] 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.

[0079] The expression "and / or", as used in this application, is to 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" are to be interpreted in the same way, i.e., "one or more" of the elements so conjoined. Other elements may possibly be present, other than the elements specifically identified by the "and / or" clause, whether or not they are related to these 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.

[0080] As used in this patent application, the expression "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 enumerated in the list of elements and not excluding every 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 expression "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.

[0081] In this application, all transitional expressions such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "composed 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.

[0082] In the present application, the term "fluid" refers to a fluid such as air, nitrogen or carbon dioxide, 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.

[0083] In all figures, continuous lines represent pipes. Their intersections without valve representation mean that there is no fluid connection between these pipes.

[0084] Throughout the description, we call:

[0085] - “charging phase”, an operating phase of the device which is the subject of the invention for charging thermal energy storage units, for liquefying at least one gas, storing each liquefied gas and for supplying cold to the customer,

[0086] - “discharge phase”, an operating phase of the device which is the subject of the invention during which the thermal energy storages are discharged, at least one liquefied gas is expanded to provide electricity and cold to the customer, and

[0087] - “pause phase” means a phase of operation of the device which is the subject of the invention during which cold, and possibly heat, is supplied to the customer, but no liquefied gas is stored in a liquefied gas tank or pumped into such a tank to be expanded and supply electricity to the customer.

[0088] EXAMPLE OF APPLICATION OF THE INVENTION (FIGURE 1)

[0089] Figure 1 shows steps in a process 20 for producing fries from whole potatoes. For each step, six pictograms indicate the common types of energy used (from left to right, cold, electricity, natural gas, steam and hot water) and the importance of energy consumption (by the importance of the thickness of the arrow shown to the right of the step in question).

[0090] Step 21 is a step of input and quality verification of whole potatoes in the industrial unit for the production of frozen fries. Step 22 is a step of cleaning and brushing the whole potatoes. Step 23 is a step of peeling the whole potatoes. Step 24 is a step of washing and sorting the peeled potatoes. Step 25 is a step of cutting the peeled potatoes into sticks. Step 26 is a step of blanching the fries. During this step 26, the sliced ​​potatoes are immersed in a hot water bath or a steam bath. The objective is to eliminate elements that can deteriorate the potatoes (bacteria, enzymes, etc.) and to precook the potato sticks. Step 27 is a step of drying the potato sticks. The sticks are dried by high quality hot air to avoid contamination.Steps 21 through 27 require steam, usually supplied by a natural gas boiler.

[0091] Step 28 is a step of frying the sticks in oil, which thus become French fries. An automatic pre-frying tunnel and a tunnel dryer are used. The vegetable oil used for frying at a temperature between 140 °C and 175 °C is heated by a heat transfer fluid (HTF) such as water vapor through a heat exchanger. Step 29 is a step of removing fat and frying oil. During this step 29, this heat transfer fluid is also used to heat the air to remove excess fat in the tunnel dryer.

[0092] Step 30 is a fries cooling step. Step 31 is a quick freezing step. Freezing is preferably carried out by direct contact with a refrigerant, or "IQF" (for "Individual Quick Freeze"). This approach is used by individual quick freezing. One technology consists of spraying a cryogenic liquid onto the food to freeze it. Another technology consists of submerging the food in a bath of cryogenic liquid to freeze it. In both cases, the cryogenic liquid is stored in tanks outside the factory. It is rarely produced on site, but is instead supplied in liquid form. To freeze 1 kg of fries, between 0.3 kg and 1.2 kg of liquid nitrogen is required. In the following description of a particular example of implementation of the invention, the value of 1.2 kg is used. A freezer can, for example, freeze three tons of fries per hour.Finally, step 32 is a packaging step for frozen fries. In total, the energy consumption for freezing three tons of fries is around 1 MWh. The liquid nitrogen consumption is then 1 kg. s. -1 .

[0093] It is observed that several steps require water vapor, several steps require heat, and several steps require the supply of frigories. Thus, to produce frozen fries, the industrial unit needs water vapor for peeling, blanching, frying, and degreasing (steps 23, 26, 28, and 29). Water vapor is generally produced by the combustion of natural gas. Natural gas is also used for drying by heating with dry air (step 27). Electricity is only used to operate conveyors, cleaning and brushing (step 22), peeling (step 23), washing and sorting (step 24), cutting fries (step 25), removing excess fat (step 29), cooling (step 30), quick freezing (step 31), and packaging (step 32).

[0094] In the following description, the present invention is applied to an industrial unit for producing potato fries using IQF freezing technology in which liquid nitrogen is sprayed onto the food for freezing. This technology is considered one of the best for preserving the quality of fries and freezing them while preventing them from clumping.

[0095] Apart from cryogenic pumps, for the sake of clarity in Figures 2 to 12, no fluid circulation pump in the pipes is shown. The description of the fluid circulations and mass flow rates, particularly during the discharge and pause phases, easily allows the person skilled in the art to position and specify the technical characteristics of such pumps.

[0096] FIRST EMBODIMENT OF THE INVENTION (FIGURES 2 TO 8)

[0097] When coupling an industrial unit, for example a frozen fries production unit, to a liquid air energy storage (LAES) system, the LAES must supply electricity to the power grid and / or the industrial unit. To optimize the energy balance of this coupling, the industrial unit is supplied with heat, cold, and liquid nitrogen. In this way, the energy consumed by the industrial unit is decarbonized using stored energy. In addition, thanks to the local production of liquid nitrogen, the production unit simplifies its liquid nitrogen supply. The production unit can thus limit, or even eliminate, the need for liquid nitrogen supplies by truck.

[0098] Figure 2 shows a simplified diagram connecting a LAES system to a production unit. The LAES system is charged during periods of low electricity demand or high electricity production (Figure 3) and it is discharged during periods of high electricity demand or low electricity production (Figure 4). When electrical balance occurs, the LAES system is put into pause mode. With the operation of the LAES, the production unit can operate 24 hours a day. Figure 2 represents, more generally, a configuration of implementation of a device 40 object of the invention with respect to an industrial unit, or client 53. The device 40 supplies electricity, heat, frigories and cryogenic liquid to the industrial unit 53.

[0099] In this first embodiment, the device 40 successively comprises, on a first air circuit leading to its liquefaction, a multi-way valve 65, a first compressor 66, a multi-way valve 61, a first thermal energy storage (in English "Thermal Energy Storage" or "TES") 55 called "intermediate", a multi-way valve 62, a second thermal energy storage 57 called "interface"), an expansion system (for example, a Joule-Thomson valve, a cryogenic air turbine, etc.) 67. The outlet of the expansion system 67 is connected to a liquid separator 69, followed by a multi-way valve 64 and a liquid air tank 52. The expansion system 67, the liquid separator 69 and the tank 52 together constitute a liquefied gas storage system. The tank 52 is, moreover, connected to a first cryogenic pump 70, the outlet of which is connected to the second thermal energy storage 57.A branch between the first compressor 66 and the multi-way valve 61 can lead a portion of the gas compressed by the first compressor 66 to the inlet of a first expander 60, for example a turbine, associated with an electricity generator.

[0100] The non-liquefied gas outlet of the liquid separator 69 is connected to the multi-way valve 65 to, jointly, recycle this non-liquefied gas and cool the gas at the inlet of the first compressor 66.

[0101] An outlet of the multi-way valve 64 is connected to a purifier 63, itself connected to an inlet of a food-grade liquid nitrogen tank 58 and to a customer inlet 53. An outlet of this liquid nitrogen tank 58 is connected to a second cryogenic pump 68 connected to the same customer inlet 53 or to another customer inlet 53. The purifier 63 extracts oxygen, carbon dioxide and other gases present in smaller proportions from the liquefied air. The purifier 63 thus provides food-grade liquid nitrogen.

[0102] A customer 53 requiring heat and cold, for example an industrial unit implementing the method described with reference to FIG. 1, is connected, by a heat inlet, to an outlet of the multi-way valve 61 and, by a cold inlet, to the outlet of the cryogenic pump 68 and to the outlet of the purifier 63. A fluid outlet returns the fluids whose heat or cold has been consumed by the customer 53, to the multi-way valve 62. It is important to note that three connections between elements described above operate in two directions, that is to say that the fluid can circulate from one of these elements to the other and vice versa. These are the connection between the multi-way valve 61 and the first thermal energy storage 55, the connection between the multi-way valve 62 and the second thermal energy storage 57 and the connection between the multi-way valve 62 and the first thermal energy storage 55.A control unit 75, for example a computer or a server, controls the operation and the state of the various elements shown in Figure 2 (and in Figures 5 and 9 for the other embodiments shown) to implement the operating phases of the device illustrated in Figures 3 and 4 (and 6 to 8 or 10 to 12, respectively). For the sake of clarity, the solenoid valves, at the inlet and / or outlet of these elements, are not shown in the figures. Similarly, the connections between this control unit 75 and these various elements and solenoid valves are not shown in the figures, for the sake of clarity. Similarly, the electrical power supplies of these various elements and solenoid valves and of the control unit 75 are not shown, for the sake of clarity of the figures.

[0103] The path of the fluid during operating phases of the device 40 is now described with reference to figures 3 and 4.

[0104] Figure 3 shows the elements, the different flows and the different pipes implemented during the charging phase of the thermal energy storages 55 and 57 and of the storage of liquid air in the tank 52 and of food-grade liquid nitrogen in the liquid nitrogen tank 58. This charging phase uses the multi-way valve 65, the first compressor 66, the multi-way valve 61, the first thermal energy storage 55, the multi-way valve 62, the second thermal energy storage 57, the expansion system 67, the liquid separator 69, the multi-way valve 64, the liquid air tank 52, the purifier 63 and the food-grade liquid nitrogen tank 58. The customer 53 is connected to the multi-way valves 61, 62 and to the purifier 63.

[0105] During this charging phase, ambient air is drawn in by the first compressor 66 and compressed. In the multi-way valve 61, this hot compressed air is divided into two parts: one part is cooled by the customer 53 by providing the energy needed to blanch and fry the sticks, the other part is cooled by passing through the first thermal energy storage 55. Both flows are collected by the multi-way valve 62. This partially cooled compressed air is then cooled by the second thermal energy storage 57, before its liquefaction by the expansion system 67. The non-liquefied air is recycled from the separator 69 to the multi-way valve 65 to cool the air entering the device 40. The liquefied air is divided into two parts by the multi-way valve 64: one part is stored in the cryogenic liquid air tank 52 to produce electricity later.The other portion is purified by purifier 63 to provide food-grade nitrogen for use in deep freezing. Some of this food-grade nitrogen is directly used by customer 53. Another portion of this food-grade nitrogen is stored in liquid nitrogen tank 58 for later use.

[0106] Figure 4 shows the elements, the different flows and the different pipes implemented during the discharge phase. This phase implements the liquid air tank 52, the cryogenic pump 70, the second thermal energy storage 57, the multi-way valve 62, the first thermal energy storage 55, the multi-way valve 61, the first pressure reducer 60, the liquid nitrogen storage 58 and the cryogenic pump 68, the customer 53 being connected to the multi-way valves 61 and 62 and to the outlet of the cryogenic pump 68.

[0107] During this discharge phase, liquid air is pumped into the reservoir 52 and compressed by the cryogenic pump 70. This liquid compressed air is then evaporated by passing through the second thermal energy storage 57. The multi-way valve 62 mixes this gaseous compressed air with compressed air from the customer 53. This mixture is superheated by passing through the first thermal energy storage 55. The multi-way valve 61 divides this hot compressed air into two parts: one part goes to the customer 53 to provide the energy necessary to blanch and fry the sticks, the other part is expanded by passing through the first expansion valve 60 to provide electricity. Simultaneously, food-grade liquid nitrogen is pumped into the reservoir 58 and used by the customer 53.

[0108] During a pause phase (not shown), food-grade liquid nitrogen is pumped into the reservoir 58 and used by the customer 53. Simultaneously, heat is extracted from the first thermal energy storage 55 to provide the energy necessary to blanch and fry the sticks.

[0109] Figure 5 details the configuration of a variant of the device illustrated in Figure 2. The device 50 comprises the elements illustrated in Figure 2. However, the multi-way valve 65 no longer receives ambient air directly. Furthermore, the second thermal energy storage 57 no longer has an input coming directly from the multi-way valve 62, nor a direct output to the multi-way valve 62 and the first expansion valve 60 is no longer directly connected to the output of the first compressor 66.

[0110] The following elements are added to those illustrated in Figure 2 in the device 50. A third compressor 51 receives the ambient air. Its outlet is connected to a third thermal energy storage 54, called “upstream”, one outlet of which is connected to the multi-way valve 65 and one outlet is connected to a second pressure reducer 59. The outlet of the second pressure reducer 59 is connected to an inlet of a fourth thermal energy storage 56, called “downstream”. Furthermore, the third thermal energy storage 54 has an inlet connected to an outlet of the second thermal energy storage 57. The fourth thermal energy storage 56 has an outlet connected to the first pressure reducer 60 and an outlet connected to an inlet of the second thermal energy storage 57.The fourth thermal energy storage 56 also has a fluid inlet from the customer 53, a fluid inlet from the multi-way valve 62 and a fluid outlet to a heater 71, for example an electric heater or a high temperature heat pump. The outlet of the heater 71 is connected to an inlet of the customer 53. Finally, a multi-way valve 72 is positioned between the purifier 63 and the liquid nitrogen tank 58. One of its outlets is connected to the tank 58 and the other to the customer 53.

[0111] The operation of the device 50 is similar to that of the device 40, but its design is better adapted to the operating specifications of currently available compressors and turbines. The charging phase, illustrated in FIG. 6, implements the second compressor 51, the third thermal energy storage 54, the multi-way valve 65, the first compressor 66, the multi-way valve 61, the first thermal energy storage 55, the multi-way valve 62, the fourth thermal energy storage 56, the second thermal energy storage 57, the expansion system 67, the liquid separator 69, the multi-way valve 64, the liquid air tank 52, the multi-way valve 72, the purifier 63 and the liquid nitrogen tank 58. The customer 53 is connected to the multi-way valves 61, 62 and 72.

[0112] During this charging phase, ambient air is drawn in by the second compressor 51 and compressed. This hot compressed air is cooled by passing through the third thermal energy storage 54. The cooled compressed air is collected by the multi-way valve 65, as well as the non-liquefied air from the separator 69, which cools the air from the third thermal energy storage 54. This partially cooled compressed air is then compressed by the first compressor 66.

[0113] The hot compressed air leaving the first compressor 66 is divided into two parts by the multi-way valve 61: one part is cooled by the customer 53 by providing the energy necessary to blanch and fry the sticks, the other part is cooled by passing through the first thermal energy storage 55. The two flows are collected by the multi-way valve 62. This partially cooled compressed air is then cooled by the fourth thermal energy storage 56 and then by the second thermal energy storage 57, before its liquefaction by the expansion system 67. The non-liquefied air is recycled from the separator 69 to the multi-way valve 65. The liquefied air is divided into two parts by the multi-way valve 64: one part is stored in the cryogenic liquid air tank 52 to subsequently produce electricity and / or frigories.The other part is purified by the purifier 63 to provide food-grade nitrogen to be used for deep freezing. The multi-port valve 72 divides the liquid nitrogen into two parts: one part of this food-grade nitrogen is directly used by the customer 53. Another part of this food-grade nitrogen is stored in the liquid nitrogen tank 58, for later use. At the end of the charging phase, the four thermal energy stores 54, 55, 56 and 57 contain calories.

[0114] Figure 7 shows the elements, the different flows and the different pipes implemented during the discharge phase. This discharge phase uses the liquid air tank 52, the cryogenic pump 70, the second thermal energy storage 57, the third thermal energy storage 54, the second pressure reducer 59, the fourth thermal energy storage 56, the first pressure reducer 60, the multi-way valves 61 and 62, the first thermal energy storage 55, the liquid nitrogen storage 58 and the cryogenic pump 68, the customer 53 being connected to the multi-way valves 61 and 62 and to the outlet of the cryogenic pump 68.

[0115] During this discharge phase, liquid air is pumped into the reservoir 52 and compressed by the cryogenic pump 70. This liquid compressed air is then evaporated by passing through the second thermal energy storage 57, then heated by the third thermal energy storage 54, before being expanded by the second expansion valve 59 to provide electricity. The air thus expanded is then heated by the fourth thermal energy storage 56 before being expanded by the first expansion valve 60 to provide electricity. The multi-way valve 62 receives cold compressed air from the customer 53. This air is superheated by passing through the first thermal energy storage 55. The multi-way valve 61 returns this hot compressed air to the customer 53 to provide it with the energy necessary to blanch and fry the sticks. Simultaneously, food grade liquid nitrogen is pumped into tank 58 by cryogenic pump 68, and used by customer 53.

[0116] During the pause phase shown in Figure 8, food grade liquid nitrogen is pumped into the reservoir 58 by the cryogenic pump 68 and used by the customer 53. Simultaneously, heat is extracted from the fourth thermal energy storage 56 to provide heat to the customer 53. However, the temperature thus obtained is not high enough for the needs of the customer 53, in particular for blanching and frying the sticks, the heater 71 heats the fluid leaving the fourth thermal energy storage 56 before its supply to the customer 53. This additional heater 71 constitutes a difference with the device 40 and makes it possible to supply the customer 53 with fluid at a higher temperature.

[0117] In embodiments, the multi-way valves, 61, 62, 64, 65 and 72, are replaced by any means for directing a flow controllable by a control unit and known to those skilled in the art. For example, such a means may be a set of pipes and solenoid valves configured to route the flows according to the embodiments described with regard to FIG. 1.

[0118] ESTIMATION OF COMPRESSED AIR MASS FLOW RATE

[0119] An estimate of the mass flow rate of compressed air can be defined as the resultant of several estimates:

[0120] 1. that of customer needs in terms of energy in thermal form,

[0121] 2. that of customer needs in terms of quantity of liquid nitrogen, and

[0122] 3. that of the targeted electricity production.

[0123] Such estimates are given below with a view to calculating the corresponding flow rates, the sum of which gives an overall flow rate, it being recalled here that these estimates depend on the specifications of the compressors, and in particular on their outlet temperatures. Concerning the air flow rate necessary to supply the customer 53 via the multi-way valve 61, it depends on the outlet temperature of the first compressor 66, here in the range of 200°C to 350°C. With the assumption of a return, at the outlet of the customer 53 to the multi-way valve 62, at a temperature of 185°C, i.e. the outlet temperature of the heat transfer fluid from the frying heat exchanger, the air flow rate to supply the heat required for the customer 53 is approximately 5.1 kg. s -1 . Thus, the mass flow rate corresponding to the customer's heat demand mentioned in point 1 above was determined.

[0124] To specify the other elements of the device 50, and estimate the mass flow rate of the first compressor 66, the durations of the different phases (charge, discharge and pause) are determined. For example, consider that the production day is divided into three time slots, the first from 00:00 to 8:00, the second from 8:00 to 16:00 and the third from 16:00 to 24:00. In this example, we assume that the charge phase occurs during the first time slot, the discharge phase occurs during the second time slot and the pause phase occurs during the third time slot. Following this assumption, all the food-grade liquid nitrogen must be produced during the first time slot, which means in 8 hours. Since the process requires a mass flow rate of liquid nitrogen of 1 kg. s -1throughout the day and that the production of this nitrogen can only take place during the charging phase, i.e. for a third of the day, the mass flow rate must be 3 kg. s -1 during this charging phase. Thus, the mass flow rate corresponding to the customer's demand for cold in the form of liquid nitrogen mentioned in point 2 above was determined.

[0125] To define the mass flow rate of the expanders, two parameters are considered: the ratio of non-liquefied air and the need to supply heat to the customer 53 continuously throughout the day, remembering that an air mass flow rate was estimated above at 5.1 kg. s -1for this heat supply. The ratio of non-liquefied air can be defined by a Mollier diagram and its two-phase curve. Assuming that the thermodynamic conditions allow 80% of the air flow from the first compressor 66 to be liquefied, there remains, at the outlet of the expansion system 67, 20% of non-liquefied air which will be recycled to the multi-way valve 65. The compressor 51 must therefore supply the 80% of new air to the system. However, 3 kg. s must be extracted from the system. -1 of nitrogen for freezing, the remainder being stored in tank 52 to produce electricity.

[0126] In addition, a hot air flow of 5.1 kg. s -1must be supplied to customer 53 all day long even though compression only takes place for a third of the day. As shown in Figure 7, during the discharge phase, the first thermal energy storage 55 is used to supply heat to customer 53 during the discharge phase, with a flow rate of 5.1 kg. s -1 . Thus, the air mass flow rate of compressor 66 must be 10.2 kg. s -1 in order to meet the thermal needs of customer 53. Since 80% of this flow is liquefied and the nitrogen content of the air is approximately 80%, we obtain 6.5 kg. s -1 of liquid nitrogen. Since 3 kg. s -1 of nitrogen is extracted for freezing, the 3.5 kg. s -1 of remaining liquid nitrogen are stored in the tank 52. Thus, the first compressor 51 has a mass flow rate of approximately 8 kg. s -1 and regulators 59 and 60 have a mass flow rate of 3.5 kg. s -1 .

[0127] The total mass flow rate is defined by adding the mass flow rate of food-grade liquid nitrogen production and the mass flow rate required to supply heat and cold to the plant and non-liquefied air.

[0128] As estimated above, a mass flow rate of 5.1 kg. s -1 is required to provide the customer 53 with the thermal energy needed to blanch and fry the fries. Therefore, a mass flow rate of 8 kg. s -1 is required at the inlet of the second compressor 51 and a mass flow rate of 10.2 kg. s -1 is required for the first compressor 66.

[0129] Regulators 59 and 60 have a mass flow rate of 3.5 kg. s -1. Finally, the thermal energy storages of the configuration were simulated by a thermal balance of the energy input and output. The overall efficiency of the device 50 is thus estimated at 60%, all energies combined, except for the frigories provided by the liquid nitrogen tank 58. To take this liquid nitrogen into account, the efficiency must be calculated by also including the energy balance of the customer 53. In particular, the food-grade liquid nitrogen used by the customer 53 can be produced on site or supplied by a third-party company. In both cases, the energy balance of the production method must be established and compared to that of the device 50.

[0130] Examples of typical operations of the compressors 51 and 66, the expanders (here, turbines) 59 and 60 and the heater 71 are given below.

[0131] In this simulation, the second compressor 51 has an inlet pressure of 1 bar and an outlet pressure between 8 and 13 bar, an inlet temperature between 10 and 20 °C and an outlet temperature between 130 and 230 °C, a mass flow rate between 7 and 12 kg. s -1 and a consumed electrical power of between 2 and 7 MW. The first compressor 66 has an inlet pressure of between 7.5 and 13 bar and an outlet pressure of between 50 and 70 bar, an inlet temperature of between 60 and 80 °C and an outlet temperature of between 200 and 350 °C, a mass flow rate of between 9 and 20 kg. s -1and an electrical power consumption of between 2 and 9 MW. The turbine of the second expander 59 has an inlet pressure of between 50 and 70 bar and an outlet pressure of between 15 and 20 bar, an inlet temperature of between 130 and 230 °C and an outlet temperature of between 35 and 70 °C, a mass flow rate of between 3 and 9 kg. s -1 and provides an electrical power of between 0.3 and 0.9 MW. The turbine of the first expander 60 has an inlet pressure of between 14.5 and 19.5 bar and an outlet pressure of 1.04 bar, an inlet temperature of between 170 and 185 °C and an outlet temperature of between -50 and -30 °C, a mass flow rate of between 3 and 9 kg. s -1and provides an electrical power of between 0.5 and 2 MW. The electric heater 71 has an inlet pressure of between 15 and 20 bar and an outlet pressure of between 15 and 20 bar, an inlet temperature of between 80 and 185 °C and an outlet temperature of between 200 and 350 °C, a mass flow rate of 5.1 kg. s -1 and an electrical power consumption of between 1 and 3 MW.

[0132] During the charging and discharging phases, the thermal energy storages 54 to 57 directly exchange their energy with the working fluid. It is noted that other thermal storage technologies can store heat and return the heat to the working fluid from a heat transfer fluid via an exchanger. In this case, the pressures can cover a range from 1 bar to 100 bar depending on the transfer fluid used.

[0133] The regulation of the flow rate of the heat transfer fluid also makes it possible to provide the working fluid with a temperature range from -196°C (liquefaction of nitrogen) to 350°C (compressor temperature) depending on the positions of each thermal energy storage in the device. Thus, depending on the embodiments, the positioning of the thermal energy storages and the pipes connecting them to the customer, the customer is provided with:

[0134] - intense cold, in the form of liquefied gas,

[0135] - moderate cold, in the form of cold gas,

[0136] - intense heat, up to 350°C and / or

[0137] - moderate heat.

[0138] The device which is the subject of the invention thus makes it possible to respond to the characteristics of the industrial process implemented by the customer, in a wide field of industrial activities, particularly agro-industrial.

[0139] During the charging phase:

[0140] - the third thermal energy storage 54 has an inlet pressure of between 8 and 13 bar, an outlet pressure of between 7.5 and 13 bar, an inlet temperature of between 130 and 230 °C, an outlet temperature of between 60 and 80 °C and a mass flow rate of between 7 and 12 kg. s -1 ,

[0141] - the first thermal energy storage 55 has an inlet pressure of between 50 and 70 bar, an outlet pressure of between 49.5 and 69.5 bar, an inlet temperature of between 200 and 350°C, an outlet temperature of between 120 and 185°C and a mass flow rate of between 4 and 10 kg. s -1, - the fourth thermal energy storage 56 has an inlet pressure of between 49.5 and 69.5 bar, an outlet pressure of between 49 and 69 bar, an inlet temperature of between 120 and 185°C, an outlet temperature of between 60 and 160°C and a mass flow rate of between 9 and 20 kg. s -1 , And

[0142] - the second thermal energy storage 57 has an inlet pressure of between 49 and 69 bar, an outlet pressure of between 48.5 and 68.5 bar, an inlet temperature of between 60 and 100°C, an outlet temperature of between -175 and -195°C and a mass flow rate of between 9 and 20 kg. s -1 .

[0143] During the discharge phase:

[0144] - the third thermal energy storage 54 has an inlet pressure of between 50 and 70 bar, an outlet pressure of between 50 and 70 bar, an inlet temperature of between 60 and 80°C, an outlet temperature of between 130 and 230°C and a mass flow rate of between 3 and 10 kg. s -1 ,

[0145] - the first thermal energy storage 55 has an inlet pressure of between 50 and 70 bar, an outlet pressure of between 50 and 70 bar, an inlet temperature of between 170 and 185°C, an outlet temperature of between 200 and 350°C and a mass flow rate of between 2 and 10 kg. s -1 ,

[0146] - the fourth thermal energy storage 56 has an inlet pressure of between 15 and 20 bar, an outlet pressure of between 15 and 20 bar, an inlet temperature of between 20 and 70°C, an outlet temperature of between 170 and 185°C and a mass flow rate of between 3 and 10 kg. s -1 , And

[0147] - the second thermal energy storage 57 has an inlet pressure of between 50 and 70 bar, an outlet pressure of between 50 and 70 bar, an inlet temperature of between -195 and -175°C, an outlet temperature of between 60 and 100°C and a mass flow rate of between 3 and 10 kg. s -1 .

[0148] During the pause phase, the fourth thermal energy storage 56 has an inlet pressure between 15 and 20 bar, an outlet pressure between 15 and 20 bar, an inlet temperature between 120 and 185 °C, an outlet temperature between 80 and 120 °C and a mass flow rate between 2 and 10 kg. s -1. The thermal energy storage 54 has a pressure of between 8 bar and 13 bar (the thermal storage 54 is depressurized at the end of expansion to bring it back to the pressure required during the compression phase), an inlet temperature of between 60°C and 80°C and an outlet temperature of between 130°C and 230°C. By means of a closed loop (not shown), this available heat increases the heat of the gas leaving the thermal energy storage 56 via an exchanger (not shown). The temperature of this gas leaving the thermal energy storage 56 thus changes from the range of 80°C to 120°C to the range of 120°C to 220°C, which reduces the energy requirement of the gas heater 71. At the same time, the thermal energy storage 54 is ventilated. The thermal energy storage 54 is brought back to a temperature of 80°C via an exchanger (not shown) with the ambient air in a closed loop.Finally, in a closed loop, the heat leaving the thermal energy storage 54 can be used by an organic Rankine cycle (ORC) generator producing electricity used by the customer 53 or by the gas heater 71.

[0149] In the simulation giving the above results, the heat transfer fluid outside the client 53 is the compressed air coming from the compressors or turbines. It is assumed that, in the thermal energy storages, a direct heat exchange is carried out with the heat transfer fluid (or "HTF") of the client 53, for example water vapor. This type of thermal energy storage offers the highest efficiency for the device 50, in comparison with a thermal energy storage which uses an intermediate thermal fluid between the compressed air and the thermal fluid of the client 53.

[0150] SECOND EMBODIMENT OF THE INVENTION (FIGURES 9 TO 12)

[0151] In the device 80, the structure of which is illustrated in Figure 9, we find all the elements of the device 50 illustrated in Figure 5. In addition, there is a fifth thermal energy storage 83, called "diversion", a multi-way valve 87, a sixth thermal energy storage called "expanded gas" 81, an air cooler 84 and three multi-way valves 82, 85 and 86. The sixth thermal energy storage 81 is positioned between the outlet of the first expansion valve 60 and a customer fluid inlet 53. The multi-way valve 82 is positioned between a customer fluid outlet 53 and an ambient air inlet and the second compressor 51. The multi-way valve 85 is positioned at the outlet of the second compressor 51 and divides the compressed air flow between the third thermal energy storage 54 and the fifth thermal energy storage 83, the outlet of which is connected to the air cooler 84.The cooled compressed gas leaving the air cooler 84 reaches the multi-way valve 86, which is also connected, at the inlet, to the fourth thermal energy storage 56 and, at the outlet, to the first expansion valve 60.

[0152] The operation of the elements unchanged between the variant of the first embodiment illustrated in figures 5 to 8 and the second embodiment is that described with reference to figures 5 to 8.

[0153] Regarding the additional elements, during the charging phase, illustrated in Figure 10, the air entering the second compressor 51 comes, in part, from the environment and, in part, from the customer 53. The hot compressed air leaving the second compressor 51 is divided into two parts by the multi-way valve 85: a first part goes to the third thermal energy storage 54, as described with reference to Figure 6, and a second part goes to the fifth thermal energy storage 83. Once partially cooled, the compressed air having passed through the fifth thermal energy storage is cooled by the air cooler 84, then passes through the multi-way valve 86 to be expanded by the first expansion valve 60. The cold expanded air leaving the first expansion valve 60 passes into the sixth thermal energy storage 81, where it heats up, and is then conveyed to the customer 53.For the operation of the device 80, if the electricity supplied by the electrical network is inexpensive, the operation of the components of the device 80 common with the device 50 is as described with reference to FIG. 6. In addition, the fifth thermal energy storage 83 and the sixth thermal energy storage 81 are used to store calories and frigories respectively during the charging phase, as illustrated in FIG. 10. At the end of the charging phase, the first five thermal energy storages 54, 55, 56, 57 and 83 store calories and the sixth thermal energy storage 81 stores frigories.

[0154] The implementation of the thermal energy storages 81 and 83 corresponds, for example, to a need of the customer 53 for cooling (obtained thanks to the thermal energy storage 81) and preheating (obtained thanks to the thermal energy storage 83). This type of situation can arise in industrial processes different from that of the production of fries, for example for the production of frozen pizzas.

[0155] Thus, during the charging phase, the ambient air is mixed with the dry air coming from the customer 53, then sucked in by the compressor 51 where it is compressed. This pressurized hot air is separated into two flows by the multi-way valve 85: one is directed towards the liquefaction system 52, 58, 63, 67 and 69, the other is directed towards the fifth thermal energy storage 83, the air cooler 84 and the expansion valve 60 for the production of cold for the customer 53.

[0156] Concerning the liquefaction process, the pressurized hot air leaving the compressor 51 passes through the thermal energy storage 54 in order to be cooled and store heat there. Once cooled, the compressed air is mixed with the non-liquefied air flow coming from the separator 69, then is compressed by the compressor 66. The heated and compressed air is then separated into two flows by the multi-way valve 61: one is directed to the customer 53 to provide heat and be cooled there, the other is directed to the thermal energy storage 55 to be cooled and store heat there. The two flows are then mixed again by the multi-way valve 62, then cooled by passing through the thermal energy storage 56, then through the thermal energy storage 57, in order to be supercooled before their liquefaction by the expansion system 67.The non-liquefied air leaving the separator 69, after having given up its frigories to the main fluid, via a heat exchanger (not shown), or to the client 53, via a heat exchanger (not shown), is mixed with a flow of air entering the multi-way valve 65, in order to start a new compression cycle.

[0157] Concerning the flow of cold production air for the customer 53, the pressurized hot air leaving the compressor 51 passes through the thermal energy storage 83 to be cooled there and to store its compression heat, then is possibly cooled by the air cooler 84 before being expanded by the expansion valve 60. The cold and expanded air is then heated, either by giving up its cold energy to the customer 53, or by passing through the thermal energy storage 81 in order to store the cold energy there, or both.

[0158] The discharge phase illustrated in Figure 11 then firstly uses the liquid air tank 52, the cryogenic pump 70, the second thermal energy storage 57, the third thermal energy storage 54, the second pressure reducer 59, the fourth thermal energy storage 56, the multi-way valve 86, the first pressure reducer 60, the sixth thermal energy storage 81. This discharge phase also uses the multi-way valves 61 and 62, and the first thermal energy storage 55. This discharge phase also uses the liquid nitrogen tank 58 and the cryogenic pump 68. The customer 53 is connected, at the output, to the multi-way valve 62 and, at the input, to the multi-way valve 61, to the output of the cryogenic pump 68 and to the output of the sixth thermal energy storage 81.

[0159] During this discharge phase, the liquid air is pumped into the reservoir 52 and compressed by the cryogenic pump 70. This liquid compressed air is then evaporated by passing through the second thermal energy storage 57, then heated by the third thermal energy storage 54, before being expanded by the second expansion valve 59 to provide electricity. The air thus expanded is then heated by the fourth thermal energy storage 56 before being expanded by the first expansion valve 60 to provide electricity.

[0160] Furthermore, by means of a pump (not shown), ambient air is cooled by the sixth thermal energy storage 81 before supplying the customer 53 with cold energy. Similarly, by means of a pump (not shown), the fifth thermal energy storage 83 is crossed by ambient air to supply the customer 53 with calories, at low temperature, for example to preheat food. Thus, the thermal energy storages 81 and 83 make it possible to supply cold air and hot air, respectively, continuously to the customer 53. It is noted that this air coming from at least one of the thermal energy storages 81 and 83 is not recycled in the device 80 but is discharged into the atmosphere through an air outlet of the customer 53.

[0161] At the same time, the multi-way valve 62 receives cold compressed air from the customer 53. This air is superheated by passing through the first thermal energy storage 55. The multi-way valve 61 returns this hot compressed air to the customer 53 to provide it with the energy necessary to blanch and fry the sticks. Simultaneously, food-grade liquid nitrogen is pumped into the tank 58 by the cryogenic pump 68, and used by the customer 53.

[0162] During the pause phase, illustrated in Figure 12, the second compressor 51 receives only air from the customer 53, via the multi-way valve 82. The hot compressed air leaving the second compressor 51 goes to the fifth thermal energy storage 83. Once partially cooled, this compressed air is optionally cooled by the air cooler 84, then passes through the multi-way valve 86 to be expanded by the first expansion valve 60. The cold expanded air leaving the first expansion valve 60 passes into the sixth thermal energy storage 81, where it cools, then is conveyed to the customer 53. At the same time, as described with reference to Figure 8, liquid nitrogen from the tank 58 and hot air from the fourth thermal energy storage 56 are supplied to the customer 53.

[0163] As a variant (not shown) of the second embodiment, a second expansion system is added at the outlet of the sixth thermal energy storage 81, for example a Joule-Thomson valve to supply a colder gas to the customer 53. The fluid used in the device which is the subject of the invention may be air, nitrogen, a mixture of air and nitrogen or carbon dioxide, for example.

[0164] In the case where the fluid is not compressed ambient air, the device comprises a low-pressure reservoir for this fluid as well as a collector for this fluid at the customer 53, for example in the French fry production line (in particular during deep-freezing). Figure 13 represents a variant of the device 40 comprising this reservoir 73 and this collector 74.

[0165] In the case where the liquefied gas is carbon dioxide CO2, it can be liquid at room temperature (20°C) under pressure (60 bar), gaseous at room pressure or in a supercritical state at pressure above 70 bar. These different states correspond to different types of storage. It should be noted that, in the food industry, CO2 and nitrogen are the main fluids that can be used for freezing, because they do not alter the food product to be frozen and do not interact with it. For the implementation of CO2, the process that is the subject of the invention is the same as for liquid nitrogen, because it is necessary to lower the temperature of the CO2 to approximately -70°C to supply the IQF system of the customer 53. The main difference with operation with liquid nitrogen is that purification is not necessary.

[0166] Each of the thermal energy storage systems described above may include a heat exchanger. In addition, it may be composed of several storage entities (identical or not), each of which may or may not include a heat exchanger.

[0167] Alternatively (not shown), the number of assemblies consisting of a heat storage and an expansion valve is increased. Their principle is to associate a thermal storage and an expansion valve, such as the third thermal energy storage 54 is associated with the second expansion valve 59 and the fourth thermal energy storage 56 (completed by the thermal energy storage 83 in the second embodiment) is associated with the first expansion valve 60.

[0168] The ability to increase the number of these assemblies comes from the fact that: a thermal energy storage can be associated with several expanders, provided that the fluid expanded between two expanders is heated by the same thermal energy storage. For example, for the third thermal energy storage 54, instead of associating only the second expander 59 with it, the following sequence is provided: the compressed air is heated by the third thermal energy storage 54 then expanded in the second expander 59 (which then produces electricity), then this cooled and partially expanded air is heated again by passing through the third thermal energy storage 54, then expanded by an additional expander (which then produces electricity), and a thermal energy storage and an expander can be associated in a unitary manner.Taking the case of the third thermal energy storage 54 and the second expansion valve 59, it is possible to create N thermal storages from the third thermal energy storage 54 (according to a very specific thermocline) and to associate with each of these thermal storages an expansion valve, the expansion rate of which is defined as a function of the outlet temperature of this thermal storage and the objective pursued by the expansion (simple supply of electricity or supply of electricity combined with recovery of the cold resulting from this expansion).

[0169] As understood from reading the preceding description, the implementation of the present invention makes it possible to:

[0170] - recover heat (and store it and / or supply it to the customer) from the compression of the air during the charging phase, with liquefaction of the air,

[0171] - recover cold from non-liquefied air and store it after the charging phase, supply electricity and cold to the customer 53 during expansion after at least one expansion valve,

[0172] - supply liquid nitrogen or liquid CO2 to customer 53 after the charging phase, and store it if necessary, bringing it to the technical specifications of customer 53 if necessary, and / or

[0173] - store electricity at certain times and then release it at another time, while providing continuous heat.

[0174] The present invention applies in particular to:

[0175] - the food industry, in particular freezing plants using liquid nitrogen or liquid CO2 and

[0176] - more generally to industrial installations comprising systems using liquid nitrogen or liquid CO2 as a means of liquefaction.

[0177] In embodiments, the multi-way valves, 61, 62, 64, 65 and 72, 82, 85, 86, and 87, are replaced by any means for directing a flow controllable by a control unit and known to those skilled in the art. For example, such a means may be a set of pipes and solenoid valves configured to route the flows according to the embodiments described with reference to FIG. 1.

Claims

CLAIMS 1. Device (40, 50, 80) for coupling at least one energy reservoir (52, 58) in the form of liquefied gas with a customer (53) having a need for cold and heat, which comprises at least one gas compressor (51, 66) configured to supply compressed gas to a liquefied gas storage system (52, 58, 67, 69) comprising each energy reservoir in the form of liquefied gas, characterized in that it further comprises: - an interface thermal energy storage (57) positioned at the inlet of the storage system and at the outlet of an energy reservoir (52) in the form of liquefied gas, configured to, alternately, cool the gas at the inlet of the storage system and heat the gas at the outlet of this energy reservoir in the form of liquefied gas, - at least one regulator (59, 60) coupled to an electricity generator, configured to receive compressed gas from this interface thermal energy storage, - a pipeline for transporting liquefied gas from an energy reservoir (58) in the form of liquefied gas to the customer, and - a control unit (75) for controlling the operation of each compressor, each expander and the interface thermal energy storage which further comprises an intermediate thermal energy storage (55), and at least two flow direction means controlled by the control unit: - a first flow direction means (61) is connected at least to a customer heat inlet (53), to the intermediate thermal energy storage (55) by a two-way connection, - a second flow direction means (62) is connected at least to a customer fluid outlet (53), to the intermediate thermal energy storage (55) and to the interface thermal energy storage by two-way connections.

2. Device (40, 50, 80) according to claim 1, in which the compressed gas is air, the liquefied gas storage system comprising: - at least one energy reservoir (52) in the form of liquefied air and - at least one energy reservoir (58) in the form of liquefied nitrogen supplied with nitrogen by a purifier (63).

3. Device (40, 50, 80) according to one of claims 1 or 2, in which the control unit (75) is configured to control at least two operating phases of the device, comprising at least: - a charging phase, during which each compressor compresses gas and the interface thermal energy storage (57) stores calories from the hot compressed gas and supplies each tank (52, 58) with energy in the form of liquefied gas, and - a discharge phase, during which the interface thermal energy storage (57) heats fluid coming from at least one energy reservoir (52) in the form of liquefied gas and supplies gas to at least one regulator (60) coupled to an electricity generator.

4. Device (40, 50, 80) according to claim 3 wherein the control unit (75) is configured to control, during the discharge phase, the supply of the customer (53) with liquefied gas coming from an energy reservoir (58) in the form of liquefied gas.

5. Device (40, 50, 80) according to one of claims 3 or 4, in which the control unit (75) is configured so that: - during the charging phase, the intermediate thermal energy storage is positioned downstream of at least one compressor (51, 66) and upstream of the interface thermal energy storage (57) and stores calories from the hot compressed gas and supplies gas to the interface thermal energy storage and - during the discharge phase, the intermediate thermal energy storage heats gas from the customer (53) and supplies heated gas to the customer.

6. Device (40) according to claim 5, wherein the control unit (75) is configured so that, during the discharge phase, the intermediate thermal energy storage (55) heats gas coming from the interface thermal energy storage (57) and supplies heated gas to at least one expander (60) coupled to an electricity generator.

7. Device (50, 80) according to one of claims 5 or 6, which comprises at least two compressors (51, 66) and, in addition, an upstream thermal energy storage (54), the control unit (75) being configured so that: a) during the charging phase: - the upstream thermal energy storage (54) is positioned downstream of at least one compressor (51) and upstream of at least one compressor (66) and the intermediate thermal energy storage (55) and stores calories from the compressed gas; and b) during the discharge phase: - the gas leaving the interface thermal energy storage passes successively through the upstream thermal energy storage and through an expander (59) coupled with an electricity generator.

8. Device (50, 80) according to one of claims 5 to 7, which comprises at least two regulators (59, 60) coupled to electricity generators and, in addition, a downstream thermal energy storage (56), the control unit (75) being configured so that: a) during the charging phase: - the downstream thermal energy storage (56) is positioned downstream of the intermediate thermal energy storage (55) and upstream of the interface thermal energy storage (57) and stores calories from the compressed gas; and b) during the discharge phase: - the gas leaving a first expander (59) coupled with an electricity generator, passes through the downstream thermal energy storage and through a second expander (60) coupled with an electricity generator.

9. Device (50, 80) according to claim 8, wherein the control unit (75) is configured to additionally control a pause phase during which gas leaving the customer (53) is reheated by the downstream thermal energy storage (56) before being supplied to the customer.

10. Device (50, 80) according to claim 9, which further comprises a gas heater (71), the control unit (75) being configured so that, during the pause phase, the gas leaving the customer (53) heated by the downstream thermal energy storage (56) is also heated by the gas heater before being supplied to the customer.

11. Device (80) according to one of claims 3 to 10, which further comprises a diversion thermal energy reservoir (83), the control unit (75) being configured so that, during the charging phase, the diversion thermal energy reservoir receives gas compressed by a compressor (51), stores calories from this compressed gas and supplies this gas to an expander (60) coupled to a generator.

12. Device (80) according to claim 11 when it depends on one of claims 9 or 10, in which the control unit (75) is configured so that, during the pause phase, a compressor (51) compresses gas, the thermal energy diversion reservoir (83) receives gas compressed by this compressor, stores calories from this compressed gas and supplies this gas to an expander (60) coupled to a generator.

13. Device (80) according to one of claims 11 or 12, wherein the control unit (75) is configured so that, during the discharge phase, the diversion thermal energy reservoir (83) provides calories to the customer (53).

14. Device (80) according to one of claims 3 to 13, which further comprises a thermal energy storage (81) of expanded gas positioned downstream of an expander (60), the control unit (75) being configured so that this thermal energy storage absorbs frigories of the expanded gas leaving this expander, during the charging phase, and supplies frigories to the customer (53), during the discharging phase.

15. Device (40, 50, 80) according to one of claims 3 to 14, in which the liquefied gas storage system (52, 58, 67, 69) comprises a separator (69) of cryogenic liquid and non-liquefied gas, and, during the charging phase, the non-liquefied gas from this separator is supplied to a said compressor (66).

16. Device (80) according to one of claims 1 to 15, which further comprises a gas transport pipe from the customer (53) to an inlet of a compressor (51).

17. Device according to one of claims 1 to 16, in which at least one flow direction directing means (61, 62) is a multi-way valve.

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