METHOD AND DEVICE FOR RECOVERING COOLNESS FROM A COLD COGENERATION ENGINE SET

Abstract

TITLE: METHOD AND DEVICE FOR RECOVERING COOLNESS FROM A COLD COGENERATION SET The cooling recovery device (20) is located between: - a cold cogeneration set (21) comprising a cryogenic liquid source (24), at least one primary heat exchanger (26, 32) heating a first fluid from the cryogenic liquid source and cooling a second fluid, each primary heat exchanger supplying gas from the first fluid under pressure to at least one turbine (29, 36) associated with a generator (30, 37), and - a cooling consumption unit (22, 23) using a third fluid as a heat transfer fluid;This device comprises: - at least one thermal energy storage tank (60, 61, 62) which stores, when the generator set is supplying electricity, cooling carried by the second fluid, in a closed-loop piping circuit (65, 67, 69) passing through at least one primary heat exchanger (26, 32) of the generator set and comprising at least one pump (63, 64), and - at least one secondary heat exchanger (70), between the piping circuit carrying the second fluid and the cooling consumption unit, which supplies cooling to the cooling consumption unit when the generator set is not supplying electricity and a pump (64) of the piping circuit extracts cooling from at least one storage tank. Figure for the abbreviation: Figure 1;

Description

Title of the invention: METHOD AND DEVICE FOR RECOVERING COLD FROM A COLD COGENERATIVE GENERATING SET Technical field of the invention

[0001] The present invention relates to a method and a device for recovering cold from a cold cogeneration generator set. It applies, in particular, to the supply of electricity and cold to an industrial unit, a residential and / or office complex or a data center. State of the art

[0002] Climate change is a major issue and all sectors are required to reduce their carbon dioxide (CO2) emissions. Generators must be "decarbonized" to meet the decarbonization requirements of digital multinationals, for example those offering an internet search engine, an online store, a social network, office software or cloud storage.

[0003] Customers requiring electricity and cooling have generator sets ("GE") at their disposal. In the event of a power outage, these generator sets are used to produce electricity and, in particular, to operate cooling units.

[0004] In 2017, global electricity consumption in data centers was 3% of the world's electricity produced. This consumption is growing rapidly. It is notable that the power supply and cooling of IT equipment consume the most energy within a data center, respectively up to 50% and 40% of total energy consumption. To reduce their carbon footprint, data center managers are developing new IT technologies to reduce cooling needs and the integration of renewable energies. From this trend, backup diesel will be banned and will have to be replaced by new solutions.

[0005] To replace generators using petroleum derivatives, several solutions are being studied and we can cite natural gas, biomethane, hydrotreated vegetable oils ("HVO"), hydrogen, synthesis gases, batteries. But these solutions are still under study and are not yet commercially available.

[0006] When generator sets are used as backup units for industries with a critical need for electricity, but also for cold (Data Centers, hospitals, etc.), existing solutions require operating the cold units of their installations, which increases the need for emergency electricity (hence oversizing of the installations) and increases the risk of overheating of the customer's installations 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 emissions of CO2 and air pollutants.

[0007] Liquid Air Energy Storage Systems (LAES) are known for storing energy in the form of liquefied air, which store energy in periods of abundance or low electricity production rates and release electricity in periods of shortage or high electricity rates. However, these systems do not provide optimal efficiency when it comes to supplying cold energy simultaneously with electricity. However, all or part of the electricity supplied can be used to cool premises, machines, industrial units or data servers. Summary of the invention

[0008] The invention comprises an improvement to a cryogenic liquid tank system, which makes it possible to supply electricity in the event of a power outage or high electricity costs on the electrical network, as well as cold corresponding to the needs of a customer, without having to use the customer's cooling unit.

[0009] This system makes it possible, in particular, to produce electricity and cold simultaneously from liquid nitrogen or liquefied air. This system is composed of liquid nitrogen or liquefied air tanks, a cryogenic pump, cryogenic turbines to produce electricity and heat exchangers connected to the customer to provide cold.

[0010] The production of liquid nitrogen or liquefied air can come from installations having nitrogen as a waste product. Liquid nitrogen or liquefied air can also be produced from the recovery of lost cold from cryogenic installations, for example a liquefied natural gas ("LNG") regasification installation in LNG terminals.

[0011] The invention comprises the introduction, into this system, of at least one thermal energy storage tank in order to optimize the recovery of cold and the supply of this cold to the customer when the electrical network is restored after a failure or when the cost of the electricity supplied by this electrical network becomes lower than a predetermined limit value. The invention thus makes it possible to supply electricity and cold as a backup, for example in the event of a failure of the electrical network, as a replacement for solutions using fossil fuels. In the event of a power failure, the cold is pumped into the tanks and the customer is supplied with cold. Thus, the cold is emptied, which provides several hours of backup (in English "back-up"). Eventually, an arbitrage is made based on the price of electricity, because the system can use fatal energy. It may therefore be advantageous to start the customer's cooling unit and recharge the cold storage tanks. If the thermal energy storage tanks are full, the surplus is evacuated by using ambient heat, for example heat from the atmosphere, with a heat exchanger. Thus, for example, one kilowatt of electricity produced results in the production of three kilowatts of cold storage, which corresponds to an overproduction of cold.

[0012] Thermal storage makes it possible to recover the excess cold produced by a cold cogeneration generator set, during power outages or when the cost of electricity on the power grid is too high, in order to return it later to the customer, before the restart of the customer's cold groups following the restoration of the power grid, or even as a replacement or supplement to these cold groups. The invention makes it possible to recover energy from a thermal point of view from a cryogenic liquid.

[0013] Thanks to each thermal energy storage tank, the impact of climatic conditions is reduced since thermal storage makes it possible to store a temperature lower than the ambient temperature when the latter is high. The thermal energy storage tanks are "full", i.e. have reached their maximum capacity for storing frigories recovered from the electricity production system and not used for cooling the customer, once the back-up system has operated. The customer's cooling units are not restarted, i.e. supplied with electricity to produce frigories, and the cold from the thermal energy storage tanks is used to cool the customer. Brief description of the figures

[0014] 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: - [Fig.l] schematically represents a first particular embodiment of the device which is the subject of the invention, - [Fig.2] represents, schematically, a first phase of operation of the device illustrated in [Fig.l], - [Fig.3] schematically represents a second phase of operation of the device illustrated in [Fig.l], - [Fig.4] represents, schematically, a third phase of operation of the device illustrated in [Fig.l], - [Fig.5] schematically represents a fourth phase of operation of the device illustrated in [Fig.l], - [Fig.6] schematically represents a second particular embodiment of the device which is the subject of the invention, - [Fig.7] schematically represents a phase of operation of the device illustrated in [Fig.6], - [Fig.8] schematically represents a third particular embodiment of the device which is the subject of the invention, in a first phase of operation, - [Fig.9] schematically represents a second phase of operation of the device illustrated in [Fig.8], - [Fig. 10] represents, schematically, a fourth particular embodiment of the device which is the subject of the invention and - [Fig. 11] represents, in the form of a flowchart, the operating steps of the first embodiment of the device which is the subject of the invention illustrated in figures 1 to 5. Detailed description

[0015] The present 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.

[0016] It should be noted from now on that the figures are not to scale.

[0017] As understood from reading this description, various concepts The inventive methods 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 shown as sequential acts in the illustrated embodiments.

[0018] The expression "and / or", as used herein and in the claims, 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 optionally be present, other than the elements specifically identified by the "and / or" clause, whether or not 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 a embodiment, to A only (possibly including elements other than B); in another embodiment, to B only (possibly including elements other than A); in yet another embodiment, to both A and B (possibly including other elements); etc.

[0019] As used in this specification and in the claims, the expression "at least one", with 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 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.

[0020] In the claims, as well as in the description below, all transitional expressions such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "composed of", and the like, are to be understood as being 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.

[0021] In the description and the claims, the term "first fluid" refers to a cryogenic liquid and the fluid resulting from this cryogenic liquid, "second fluid" refers to a heat transfer fluid used in thermal energy storage tanks, "third fluid" refers to a fluid used by a consumer of frigories, or customer, "fourth fluid" refers to a heat transfer fluid carrying frigories between the second fluid and the third fluid and "fifth fluid" refers to a fluid carrying frigories between the second fluid and a heat exchange tower with the ambient air.

[0022] In the description and the claims, the term “primary” refers to the heat exchangers located in the path of the first fluid upstream of a turbine and “secondary” heat exchangers located on the path of the second fluid.

[0023] In the description and the claims, the term “pump” includes pumps, fans (in English “blower”) and compressors.

[0024] In the description and the claims, the term "client" refers to an installation consuming cold, for example a unit for producing goods, an office or residential building or a data center.

[0025] In Figures 2 to 5 and 7 to 9, the states of the valves are represented by thick oblique lines across the pipes connected to them, which signify that the valve in question prohibits the entry or exit of fluid on this pipe.

[0026] First embodiment, figures 1 to 5

[0027] In [Fig.l], we observe a particular embodiment of the device for recovering cold from a cold cogeneration generator set, which is the subject of the invention. This device 20 is inserted between a cold cogeneration generator set 21, on the one hand, and a system 22 for supplying cold to a customer 23, on the other hand.

[0028] The cold cogeneration generator set 21 stores energy in the form of a first cryogenic liquid and cogenerates electrical energy and colds, by changing the state of the cryogenic liquid into gas. The source of cryogenic liquid comprises at least one cryogenic liquid tank 24. This cryogenic liquid is, for example, liquefied air, liquefied nitrogen, liquefied natural gas, liquefied hydrogen, liquefied carbon dioxide CO2, liquefied helium or liquefied synthetic gas. The production of liquid nitrogen can come from installations having nitrogen as a lost product. Liquid nitrogen or liquefied air can also be produced from the recovery of lost cold from cryogenic installations, for example regasification of liquefied natural gas ("LNG") in LNG terminals.The first cryogenic liquid may also be produced (in a manner known per se and not shown in the figures) in the generator set 21, by using electricity to compress the gas to be cryogenized. The cryogenic liquid may also be received from a remote source, for example by truck or by a pipeline.

[0029] Throughout the description, the term "power cut" is used to designate both the absence of electric current on the electrical network and the triggered shutdown of the consumption of electric current from this network, when the cost of electricity on the electrical network is higher than a predetermined limit value.

[0030] The cold cogeneration generator set 21 makes it possible to supply electricity in the event of a power outage as well as cold corresponding to the needs of the customer 23, without having to use the cold group of the customer 23 during the power outage, that is to say without electrically supplying this cold group of the customer 23. This cogeneration generator set cold generator 21 comprises each reservoir 24 of cryogenic liquid, a cryogenic pump 25, cryogenic turbines 29 and 36 for producing electricity and primary heat exchangers 26 and 32 providing cold. In the remainder of the description, the term "the reservoir" 24 is used to designate the assembly of at least one reservoir of cryogenic liquid. Preferably, at least three reservoirs 24 are implemented, one being used for the production of electricity, as described below, another being full and waiting to be used and a third being in the process of being filled.

[0031] In the embodiment shown in [Fig.l], the cold cogeneration generator set 21 comprises, upstream, at least one cryogenic tank 24, a pump 25 moving liquid from each cryogenic tank to an upstream primary heat exchanger 26, possibly via a multi-way valve 27 for injecting additional cryogenic liquid into the upstream primary heat exchanger 26 at the desired temperature and / or a multi-way valve 28 for bypassing the upstream heat exchanger 26. The cold cogeneration generator set 21 comprises, downstream of the upstream primary heat exchanger 26, a high-pressure cryogenic turbine 29 associated with an electric generator 30, possibly via a multi-way valve 31 for supplying additional fluid.The outlet of the high-pressure cryogenic turbine 29 is connected to a downstream primary heat exchanger 32, possibly via a multi-way valve 33 for bypassing the downstream heat exchanger 32 and / or a multi-way valve 34 connected to the possible multi-way valve 28, by a pipe 35. The outlet of the downstream heat exchanger 32 is connected to a low-pressure turbine 36 associated with an electric generator 37, possibly via a multi-way valve 38 for supplying additional fluid. The outlet of the low-pressure turbine 36 is connected to a possible multi-way valve 39 connected to the possible multi-way valve 33, by a pipe 40 and / or to a valve 41 for discharging the decompressed cryogenic fluid.

[0032] In variants, the downstream heat exchanger 32 takes the form of a heater, for example an electric resistance heater or another heat generator.

[0033] In the embodiment described with reference to [Fig. 1], the system 22 for supplying cold to the customer 23 comprises a first circuit of fourth fluid closed around a cooling unit 45 (generally a heat exchanger) whose hot inlet 46 and cold outlet 47 are connected to the customer 23. This first circuit comprises a pump 48, a chiller 49, generally a heat exchanger, a heat exchanger 72 on a pipe 71, and a set of multi-way valves. The heat exchanger 72 is, moreover, connected to the multi-way valve 41, which supplies it with a gas colder than the fourth fluid circulating in this heat exchanger 72. Generally, the fourth fluid circulating in the first circuit is water. This water is cooled by the cooler 49 before cooling the third fluid (generally air) circulating between the cooling unit 45 and the customer 23.

[0034] In the embodiment described with reference to [Fig. 1], a second fifth fluid circuit comprises the cooler 49, a pump 50 and a tower for exchanging heat with the ambient air 51, supplemented by a downstream secondary heat exchanger 52 connected, moreover, to the outlet of an upstream secondary heat exchanger 70 returning the second fluid to the thermal energy storage tanks 60, 61 and 62. Two multi-way valves forming a by-pass allow the fluid going from the heat exchanger 70 to the tanks 60, 61 and 62 to bypass the heat exchanger 52.

[0035] In other embodiments (not shown), the cold supply system 22 to the customer 23 comprises only one of the first and second circuits described above or none of these circuits. In all cases, the customer 23 is thermally connected to the heat exchanger 70 located on one of the closed loops of the cold recovery device 20.

[0036] The device 20 for recovering cold energy from the cold cogeneration generator set 21 comprises at least one thermal energy storage tank. In this embodiment, three thermal energy storage tanks 60, 61 and 62 are implemented. Of course, in variants, the number of thermal energy storage tanks may be different.

[0037] The cold recovery device 20 also comprises at least one pump. In this embodiment, two pumps 63 and 64 are implemented. Of course, in variants, the number of pumps may be different. It is, however, preferably equal to the number of upstream heat exchangers or downstream heat exchangers of the cold cogeneration generator set 21.

[0038] The outlets of the thermal energy storage tanks 60, 61 and 62 are connected to the inlets of the pumps 63 and 64, via a pipe 65 and a multi-way valve 66 and, as regards the pump 64, a multi-way valve 82. The outlet of the pump 63 is connected to an inlet of the upstream heat exchanger 26, one outlet of which is connected to the inlet of the thermal energy storage tanks 60, 61 and 62, via a pipe 67 and a multi-way valve 68. The outlet of the pump 64 is connected to an inlet of the downstream heat exchanger 32, one outlet of which is connected to the inlet of the thermal energy storage tanks 60, 61 and 62, via a pipe 69, a heat exchanger 70 and the multi-way valve 68. Two multi-way valves 75 and 76 form a bypass allowing the second fluid leaving the pump 64 to directly join the pipe 69 without passing through the downstream heat exchanger 32. The pipes 67 and 69 are connected by a mixer (here taking the form of a multi-way valve) 74 which makes it possible to mix the flows coming from these pipes. This mixer 74 facilitates the management of the temperature at the inlet of the thermal energy storage tanks 60, 61 and 62. Preferably, this temperature is stabilized by the mixer 74, so that there is no temperature variation which would cause instabilities. The multi-way valve 74 is also connected, via a pipe 84, to the common outlet of the thermal energy storage tanks 60, 61 and 62.

[0039] The heat exchanger 70 is connected to the first circuit of the cold supply system 22, by a pipe 71 located between the pump 48 and the cooler 49. The heat exchanger 72 is mounted in series with the heat exchanger 70, on the pipe 71.

[0040] Preferably, the flow rate of the pump 64 is close to or equal to the nominal flow rate of the heat exchanger 70, itself specified by the flow rate necessary for cooling the customer 23. The flow rate of the pump 63 is preferably twice that of the pump 64.

[0041] Preferably, the cold recovery device 20 also comprises at least one heat exchanger 77 with the ambient air, which is implemented when the thermal energy storage tanks 60, 61 and 62 are full, that is to say when their maximum cold storage capacity is reached. Preferably, two heat exchangers 77 with the ambient air are provided in order to take into account the problems of freezing of these exchangers, the cryogenic fluid freezing the water in the humid ambient air. A multi-way valve 78 then makes it possible to direct the second fluid towards this or these heat exchanger(s) 77. The multi-way valve 78 is also connected to the multi-way valve 82.

[0042] In the cold cogeneration generator set 21, the cryogenic liquid stored in the cryogenic tank 24 is pumped by the pump 25 and changes state in the upstream heat exchanger 26 to take a gaseous form under high pressure. It should be noted here that there is not necessarily a change of state of the cryogenic liquid in the upstream heat exchanger 26. For example, supercritical fluids, such as nitrogen or air at 50 bar do not change state even if they heat up in the upstream heat exchanger 26. In other cases, the upstream heat exchanger 26 takes the form of an evaporator changing the cryogenic liquid to the gaseous state.

[0043] Downstream of its expansion in the high-pressure turbine 29, this first fluid has a lower pressure and temperature than upstream of this turbine 29. The downstream heat exchanger 32 heats this first fluid so that it drives the low-pressure turbine 36. Downstream of its expansion in the low-pressure turbine 36, this gas has a lower pressure and temperature than upstream of this turbine 36.

[0044] Of course, other stages, each comprising a downstream heat exchanger upstream of a turbine associated with an electric generator, can be arranged downstream of the low pressure turbine 36.

[0045] On the side of the cold supply system 22 to a customer 23, in the first circuit, the heat exchanger 72 and / or the cooler 49, supplied by the pump 48, cool the fourth fluid (generally water) passing through the cooling unit 45, which, itself, cools the third fluid circulating between this cooling unit 45 and the customer 23. In the second circuit, the heat exchange tower with the ambient air 51 and / or the heat exchanger 52, supplied by the pump 50, cool a fifth fluid which cools, in turn, the fourth fluid circulating in the first closed circuit, via the cooler 49. Thus, the fifth fluid coming from the tower 51 is used to cool the cooler 49, a cold group which therefore produces heat which must be evacuated when there is neither production of electricity nor use of the thermal energy storage tanks 60, 61 and 62.On the other hand, the fifth fluid can be used to heat the second fluid during the release of frigories by the reservoirs 60, 61 and 62, as described below, with reference to figures 3, 4, 5 and 9.

[0046] Depending on the states of the multi-way valves of these two circuits, the water circulating in the first circuit is thus cooled by the heat exchanger 72, and, via the cooler 49, by the heat exchanger 52 and / or by the cooling tower 51.

[0047] Example of implementation of the first embodiment

[0048] For example, in the case of a customer 23 consisting of a data center, cold air is blown onto the floor of the computer room, passes through the computer racks to cool them, and is then extracted through the roof of the computer room. Consequently, air convection is created in the room. The air arriving at the inlet 46 of the cooling unit 45 is at approximately 30°C and the air leaving this unit 45 through its outlet 47 is at approximately 20°C. The water entering this unit 45 is at approximately 7°C and the water leaving it is at approximately 12°C. If a constant water mass flow rate of 41 kg.s1 is assumed, the energy that must be dissipated is approximately 850 kWh per hour. This means a heat exchanger power of 850 kW.

[0049] The device 20 for recovering cold from the cold cogeneration generator set 21, which is the subject of the invention, forms a closed-loop circuit comprising at least one of the thermal energy storage tanks 60, 61 and 62, at least one of the pumps 63 and 64 and at least one of the upstream 26 and downstream 32 heat exchangers. This closed-loop device can operate between 1.5 bar and 20 bar and at temperatures ranging from - 130°C to 50°C using dry air for example. Other temperature ranges can be used with another second fluid. For example, carbon dioxide CO2 is liquid when it is at 40 bar and a temperature below 5°C.

[0050] In the embodiment shown in [Fig. 1], the cold recovery device 20 introduces three thermal energy storage tanks 60, 61 and 62 which improve the recovery of colds and two pumps 63 and 64 integrated in two interconnected closed loops. The pressure of the closed loops is in a range of values ​​from 3 to 12 bar, with a pressure drop of up to 5 bar, with a preferred value of 1 bar.

[0051] In [Fig. 2], we observe a phase of electricity production by the cold cogeneration generator set 21, storage of colds by the thermal energy storage tanks 60, 61 and 62 and supply of colds to the customer 23. The pipes which are not traversed by any fluid are indicated by thick oblique bars. For example, no fluid circulates directly between the multi-way valves 75 and 76. In this phase, the pump 50 is preferably stopped, because the colds supplied by the heat exchangers 70 and 72 are sufficient to supply the necessary colds to the customer 23. The second circuit of the cold supply system 22 is therefore stopped, with the exception of the pump 48 which allows the transfer of colds from the system 21 to the customer 23.Consequently, the multi-way valve positioned at the outlet of the heat exchanger 72 prevents the passage of fluid towards the cooler 49 and the multi-way valves positioned downstream of the heat exchanger 70 prevent the passage of fluid into the heat exchanger 52.

[0052] The thermal energy storage tanks 60, 61 and 62 are preferably associated, via a multi-way valve 78, with at least one (preferably two to take into account the risks of freezing) heat exchanger 77 with the ambient air, in order to guarantee operation of the device 20, even after the tanks 60, 61 and 62 have reached their maximum cold storage capacity.

[0053] As examples, it being noted that “of the order of” means to within plus or minus 10°C: - the temperature of the cryogenic fluid at the outlet of the cryogenic pump 25 is between -190°C and -150°C, - the temperature of the cryogenic fluid at the outlet of the upstream heat exchanger 26 is between 0°C and 50°C, - the temperature of the cryogenic fluid at the outlet of the high pressure turbine 29 is between -70°C and -30°C, - the temperature of the cryogenic fluid at the outlet of the downstream heat exchanger 32 is between 0°C and 50°C, - the temperature of the cryogenic fluid at the inlet of the heat exchanger 72 is between -130°C and 0°C, - the temperature of the cryogenic fluid at the outlet of the heat exchanger 72 is of the order of 0°C, - the temperature at the outlet of the thermal energy storage tanks 60, 61 and 62 is between -140°C and 50°C, - the temperature in the first closed loop of the cold recovery device 20 comprising the pump 63, at the outlet of the upstream heat exchanger 26 is of the order of -170°C, - the temperature in the second closed loop of the cold recovery device 20 comprising the pump 64, at the outlet of the downstream heat exchanger 32 is between -70°C and -30°C, - the temperature in the second closed loop of the cold recovery device 20 comprising the pump 64, at the outlet of the heat exchanger 70 is of the order of 2 °C, - the inlet temperature of the thermal energy storage tanks 60,61 and 62 is between -130°C and -100°C, , - the temperature on the first circuit of the cold supply system 22 at the inlet of the heat exchanger 70 is of the order of 12°C, - the temperature on the first circuit of the cold supply system 22 at the outlet of the heat exchanger 70 is of the order of 9°C, - the temperature on the first circuit of the cold supply system 22 at the outlet of the heat exchanger 72 is of the order of 7°C.

[0054] In [Fig. 3], we observe a first phase of destocking of frigories by the thermal energy storage tanks 60, 61 and 62 and of supplying frigories to the customer 23, in the absence of production of electricity by the cold cogeneration generator set 21. The circulation of the second, fourth and fifth fluids is indicated by arrows. The pipes which are not crossed by any fluid are indicated by thick oblique bars. In this phase, the pipes of the generator set 21 are therefore not traversed by any fluid, the fluid circulates directly from the multi-way valve 75 to the multi-way valve 76 without passing through the downstream heat exchanger 32, just as no fluid flows through the pipe leading from the exhaust valve 41 to the heat exchanger 72. Simultaneously, only the second closed loop of the cold recovery device 20, which comprises the pump 64, operates.The first loop, comprising the pump 63, therefore does not operate. On the other hand, the heat exchanger 52 is crossed by the fluid coming from the heat exchanger 70 and, on the first circuit of the cold supply system 22, the cooling fluid coming from the heat exchanger 72, inactive, returns di. directly to the cooling unit 45. Preferably, a bypass (not shown) is then open and prevents the fluid from passing through the heat exchanger 72.

[0055] The pump 50 and the tower 51 can operate if necessary and according to the configurations: in embodiments, the heat exchanger 52 is replaced by an ambient air-fluid exchanger. However, if the pump 50 and the tower 51 are operating, the fluid does not pass through the cooler 49, thanks to a bypass (not shown).

[0056] In the first phase of destocking of frigories illustrated in [Fig. 3], only the thermal energy storage tank 60 is traversed by a fluid, the tanks 61 and 62 not being so. In a second phase of destocking of frigories illustrated in [Fig. 4], only the thermal energy storage tank 61 is traversed by a fluid, the tanks 60 and 62 not being so. In a third phase of destocking of frigories illustrated in [Fig. 5], only the thermal energy storage tank 62 is traversed by a fluid, the tanks 60 and 61 not being so.

[0057] From the pump 64, the path of the second fluid passes successively through the multi-way valves 75 and 76, the heat exchanger 70, the heat exchanger 52, the multi-way valve 74, the pipe 84, one of the thermal energy storage tanks 60, 61 or 62, the multi-way valves 68 and 78, then the multi-way valve 82.

[0058] Thus, the cold recovery device 20 comprises at least two thermal energy storage tanks 60 to 62, and a multi-way valve 68 configured so that, in turn, a single thermal energy storage tank 60 to 62 is passed through by the second fluid in motion, when the cold co-generation generator set 21 is not supplying electricity and the pump 64 is operating. It is noted that, when loading the tanks 60 to 62 with cold, this loading can also be carried out sequentially, one of these tanks after the other.

[0059] In [Fig. 3], the cold of the second fluid is first transferred to the customer 23 by the heat exchanger 70 then this second fluid is heated by the outside air thanks to the exchanger 52, the heat coming from the tower 51 or from a heat exchanger (not shown) between the fifth heat transfer fluid and the ambient air (possibly in forced mode). Thus, heat is recovered for the next cycle and the climatic impact is reduced, because the cooling time intervals of the customer 23 can be chosen with the thermal storage.

[0060] As examples, it being noted that “of the order of” means to within plus or minus 10°C: - the temperature at the outlet of the active thermal energy storage tank, 60, 61 or 62 is between -130°C and -100°C, - the temperature in the second closed loop of the cold recovery device 20, at the outlet of the valve 76, is between -130°C and -100°C, - the temperature in the second closed loop of the recovery device frigories 20, at the outlet of the heat exchanger 70 is of the order of 2°C, - the temperature in the second closed loop of the frigories recovery device 20, at the outlet of the heat exchanger 52 is of the order of 15°C, - the temperature on the first circuit of the cold supply system 22 at the inlet of the heat exchanger 70 is of the order of 12°C, - the temperature on the first circuit of the cold supply system 22 at the outlet of the heat exchanger 70 is of the order of 7°C, - the temperature on the second circuit of the cold supply system 22 at the inlet of the heat exchanger 52 is of the order of 24°C. - the temperature on the second circuit of the cold supply system 22 at the outlet of the heat exchanger 52 is of the order of 19°C. The role of the heat exchanger 52 is then to heat the fluid coming from the first circuit connected to the exchanger 70. The cooler 49 then does not operate as indicated previously. Thanks to the heat exchanger 52 and the heating of the return fluid, climatic conditions are largely eliminated. Indeed, the recovered heat can be used during the next production cycle by the cold cogeneration generator set 21, independently of the outside temperature. This temperature is thus maintained while limiting heat losses.

[0061] Second embodiment, figures 6 and 7

[0062] The second embodiment of the device 80 for recovering cold energy which is the subject of the invention, illustrated in figures 6 and 7, is identical to the device 20 of the first embodiment, except that a multi-way valve 81 and a pipe 83 are added thereto. The multi-way valve 81 is positioned on the pipe leading from the heat exchanger 70 to the multi-way valve 74. The pipe 83 goes from the multi-way valve 81 to the multi-way valve 82, passing through a multi-way valve connected to the multi-way valve 78. There is thus, on the second closed loop of the cold recovery device 80, a bypass of the thermal energy storage tanks 60, 61 and 62 for the second fluid moved by the pump 64. Thus, only the pump 63 supplies the thermal energy storage tanks 60, 61 and 62 with cold. The two closed loops, each comprising one of the pumps 63 or 64, are thus independent.

[0063] In [Fig.7], we observe a phase of electricity production by the cold cogeneration generator set 21, of storage of cold energy by the thermal energy storage tanks 60, 61 and 62 and of supply of cold energy to the customer 23 by the device 80. The pipes which are not traversed by any fluid are indicated by thick oblique bars. In this phase, the pump 50 is stopped. The second circuit of the cold supply system 22 is therefore stopped. Consequently, the multi-way valve positioned at the outlet of the heat exchanger 72 prohibits the passage of water to the cooler 49 and the multi-way valves positioned downstream of the heat exchanger 70 prohibit the passage of fluid into the heat exchanger 52 and the return of fluid from the heat exchanger 70 to the multi-way valve 68. The path of the second fluid in the first closed-circuit loop passing through the pump 63 is represented by solid arrows. The path of the second fluid in the second closed-circuit loop passing through the pump 64 is represented by broken arrows.

[0064] This second embodiment makes it possible to cool the tanks 60, 61 and 62 down to -170°C, while heating the cryogenic fluid in the downstream heat exchanger 32, whereas the first embodiment did not make it possible to reach such a temperature in such a configuration, due to the mixing of the fluids coming from the upstream heat exchanger 26 and the heat exchanger 70.

[0065] The second, third and fourth operating phases illustrated in figures 3, 4 and 5 are implemented by the device 80 in the same way as by the device 20, no fluid then circulating on the pipe 83.

[0066] Of course, the second embodiment allows an alternation of the first phase illustrated in [Fig.2], by not circulating any fluid on the pipe 83, and of the first phase illustrated in [Fig.7], by circulating fluid on the pipe 83. It is thus possible to lower the temperature of the reservoirs 60, 61 and 62 more quickly, in the configuration illustrated in [Fig.2], for example down to -100°C, since the flow of fluid in the reservoirs 60, 61 and 62 is higher. Then, this temperature is lowered beyond -110°C, in the configuration illustrated in [Fig.7], with only the flow of fluid from the first closed loop, the temperature of which at the inlet of these reservoirs is lower.

[0067] Third embodiment, figures 8 and 9

[0068] The third embodiment of the device 90 for recovering cold energy which is the subject of the invention, illustrated in figures 8 and 9, is identical to the device 20 of the first embodiment, except that the pipe 84 is removed, the multi-way valve 74 is replaced by a multi-way valve 85, a multi-way valve 86 replaces a multi-way valve of the device 20, a pipe 87 connects the multi-way valve 86 to the multi-way valve 82.

[0069] This third embodiment is particularly suitable for the case where the temperature of the second fluid in the thermal energy storage tanks 60, 61 and 62 is not compatible with the thermal operating specifications of the pump 64. In the device 90 during the thermal energy destocking phase, the second fluid extracted from the thermal energy storage tanks 60, 61 and 62 is directly directed towards the heat exchanger 70 in interface with the cold supply system 22, via the multi-way valve 78. This second fluid heats up within the heat exchanger 70, recovering the heat from the customer 23 and giving up its cold to the latter. The second fluid thus heated possibly passes through the heat exchanger 52 in interface with the cold supply system 22 connected to a hot source, for example the tower 51, in order to be superheated there. This second superheated fluid then passes through the multi-way valve 86 and the pipe 87 to reach the inlet of the pump 64 which slightly compresses the second fluid. At the outlet of the pump 64, the second fluid returns to the thermal energy storage tanks 60, 61 and 62, in order to be cooled there while giving up its heat which is thus stored. The second fluid is then ready for a new cooling cycle of the customer 23.

[0070] This embodiment reduces the thermal stresses applied to the pump 64.

[0071] [Fig. 9] also represents a thermal energy storage discharge phase, during which cold stored in the thermal energy storage tanks 60, 61, 62 are recovered. In this phase, these cold are used to supply the cooler 49 (to cool the customer's refrigeration unit 23) without using the heat exchanger 70. The configuration described in [Fig. 9] also makes it possible to store cold at night to deliver it during the day.

[0072] Fourth embodiment, [Fig. 10]

[0073] The fourth embodiment of the cold recovery device 100 which is the subject of the invention, illustrated in [Fig. 10], is identical to the device 20 of the first embodiment, except that the pumps 63 and 64 are replaced by a single pump 92, the cold cogeneration generator set 91 only comprises a single heat exchanger 26 for heating the cryogenic fluid and a single closed loop 93 of the device 100 passes through this single heat exchanger 26, through a heat exchanger 70 connected to the customer 23, through a thermal energy storage tank 61 and through the pump 92.

[0074] The thermal energy storage tank 61 is preferably associated, via a multi-way valve 98, with at least one (preferably two to take into account the risks of freezing) ambient heat exchanger 77, in order to guarantee unlimited operation of the device 100, even after the tank 61 has reached its maximum cold storage capacity, subject to having a supply of cryogenic liquid.

[0075] Optionally, an exchanger, similar to the exchanger 52 of the first two embodiments, positioned downstream of the heat exchanger 70 on the closed loop, makes it possible to benefit from additional heat (fatal or ambient, via a cooling tower, for example).

[0076] Method of operating the device which is the subject of the invention

[0077] [Fig. 11] illustrates an example of a succession 120 of steps implemented by the device illustrated in Figures 1 to 5. These steps are performed by a computer system with memory for software that controls the operation of the valves and pumps illustrated in Figures 1 to 5.

[0078] It is considered that a price limit value for the electricity supplied by the electricity network has been set and that exceeding this price limit value causes a stoppage of electricity consumption from this electricity network, subject to having cryogenic liquid in the tank 24, this triggered stoppage being equivalent, from the point of view of the operation of the system, to a power cut on the electricity network.

[0079] During a step 101, this computer system determines whether electricity is available on the electricity network. If so, during a step 102, the computer system performs an arbitration to determine whether production of cryogenic liquid, i.e. storage of energy in this liquid form, must be carried out. For example, this arbitration takes into account the price of electricity and / or power cuts expected or observed in the past. For example, if the price of electricity is low at a certain time of day, and higher at another time, the production of cryogenic liquid is carried out during the hours when the price is lowest.According to another example, if power outages are planned or foreseeable and the quantity of cryogenic liquid available does not allow the production of the electrical energy that will be necessary during these upcoming power outages, with a safety margin, the production of cryogenic liquid is carried out. The production of cryogenic liquid is carried out during a step 103, according to known techniques. If no production of cryogenic liquid is to be carried out, the operation returns to step 101. When the cryogenic liquid tank is sufficiently full (the quantity to be stored being determined during the arbitration step 102), the operation returns to step 101.

[0080] Of course, if the device does not include means for producing cryogenic fluid, steps 102 and 103 are not carried out, the reservoir 24 then being recharged with cryogenic fluid from an external source (not shown).

[0081] If the result of step 101 is negative, that is to say that there is no electricity available on the electricity network, during a step 104, the computer system controls the valves and pumps to put them in the configuration illustrated in [Fig.2]. It is observed that, in parallel with the production of electricity, frigories are supplied to the customer 23, which reduces his need for electricity. The surplus frigories generated by the production of electricity is stored in the tanks 60, 61 and 62, during a step 105. When the frigories storage capacities of the tanks 60, 61 and 62 are reached, the surplus frigories are dissipated in the heat exchanger(s) 77.

[0082] When electricity becomes available again, which is determined during a step 106, the computer system performs an arbitration, during a step 107, to determine whether frigories must continue to be supplied to the customer 23. For example, this arbitration takes into account the daily evolution of the price of electricity, to supply cold to the customer at the times when electricity is most expensive, in order to reduce its electricity consumption at these times. If it is determined that the supply of cold to the customer 23 must not continue, the procedure proceeds to step 111. If it is determined that the supply of cold to the customer 23 must continue, during a step 108, an arbitration is performed to determine whether the heating of the thermal energy storage tanks 60, 61 and 62 must be accelerated during the supply of cold to the customer 23.For example, if power outages tend to be frequent, this acceleration is caused, by using the heat exchanger 52, during the cold supply step following a power restoration, in order to maximize the efficiency of the cryogenic fluid when the cold cogeneration generator set 21 is operating. Conversely, if power outages tend to be temporally spaced, this acceleration is not caused to maximize the quantity of frigories transmitted to the customer 23 after the power restoration.

[0083] Then, during a step 109, the computer system controls the valves and pumps to put them successively in the configurations described in figures 3 to 5, if an acceleration of the heating of the tanks is decided, or by direct passage of the second fluid from the heat exchanger 70 to the multi-way valve 74, without passage through the heat exchanger 52, if it is decided not to accelerate the heating of the tanks.

[0084] Once the frigories stored in the tanks 60, 61 and 62 are exhausted, calories are stored in these tanks to improve the efficiency of future electricity production, which consumes heat, during a step 110, then we return to step 101.

[0085] During step 111, the computer system performs an arbitration to determine whether frigories from the client 23 must be stored, according to the same criteria as during the arbitrations previously presented. If yes, during a step 112, the client 23 puts its cooling unit into operation and the pump 64 is activated so that the second fluid receives frigories from the client 23, via the heat exchanger 70 and stores them in the thermal energy storage tanks 60, 61 and 62. Then, we return to step 101.

[0086] The flowchart described in [Fig.l 1] is a simplified flowchart for educational purposes. In practice, if the device is associated with means for producing cryogenic liquid, steps 102, 107 and 111 are combined into a single step to carry out joint arbitrations and optimize the supply of electricity at the lowest cost. and frigories to customer 23.

[0087] As a variant of the operation described with respect to [Fig. 1 1], during periods of high outside temperature, and when the thermal energy storage tanks 60, 61 and 62 are empty, the cooler 49 operates as well as the pump 50, as illustrated in [Fig. 9]. But, instead of using the tower 51 as described above, the exchanger 52, the pump 64 and the tanks 60, 61, 62 are used to supply frigories to the cooler 49. Indeed, the temperature in the tanks 60, 61 and 62 is lower than the outside temperature. Thus, the device which is the subject of the invention recharges the tanks 60, 61 and 62 with frigories during the night, thanks to the heat exchanger 77, at lower temperatures than during the day and returns them to the customer 23 during the day. It is observed that this operation does not impact thermal storage if it is used to recover the cold from the generation of electricity, and even favors it.In fact, in this operation, thermal storage is used to perform "free cooling" in order to recover the cold from the night and use it during the day. This does not negatively impact the operation of the system in the event of a power outage, because heat will have been recovered during the day. On the contrary, its performance is improved, because we have higher temperature heat.

[0088] Conclusions and variant embodiments

[0089] As understood from the foregoing description, in the context of supplying electricity and cooling to a data center or other type of customer 23, the device that is the subject of the invention can provide cooling and electricity in the event of a power outage. Even in the absence of a power outage, this device can provide emergency cooling continuously. According to a preliminary study, the overall energy efficiency of this device is between 80% and 95%, compared with an overall efficiency of 70% in the absence of thermal energy storage.

[0090] According to this preliminary study, a net power (equal to the electrical power produced by the generators 30 and 37 associated with the turbines 29 and 36, from which the electrical power consumed by the cryogenic pump 25 and by the compressors, pumps 48, 50, 63 and 64 is subtracted) of 1 MW can be achieved. It is noted that the cryogenic liquid tank 24 must be refilled during operation if the power outage is longer than the initially planned duration and after each use.

[0091] The cold recovery device 20 or 80 comprises two closed loops, a thermal energy storage system, 60, 61 and 62, and a heat exchanger connected to the first circuit of the cold supply system 22. The first closed loop transports the heat from the thermal energy storage system, 60, 61 and 62, to the upstream heat exchanger 26 by means of the pump 63. This closed loop transports the cold energy recovered from the cryogenic liquid to the thermal energy storage system, 60, 61 and 62. In the same way, the second closed loop transports the heat from the thermal energy storage system 60, 61 and 62 to the downstream heat exchanger 32 by means of the pump 64. The cold energy recovered from the downstream heat exchanger 32 is transported to the cold supply system 22 to cool it. The heat from the customer 23 is recovered by the heat exchanger 70 and transported, in the configuration illustrated in [Fig.2], to the thermal energy storage system 60, 61 and 62 by the second closed loop and, in the case of the device 80 in the configuration illustrated in [Fig.7], to the downstream heat exchanger 32.

[0092] Operation of the heat exchanger 72 increases the cooling of the client 23. Optionally, the heat exchanger 52 also recovers a portion of the heat from the client 23 for transport to the thermal energy storage system 60, 61 and 62.

[0093] Each closed loop of the cold recovery device 20 or 80 uses the same working fluid which may be, for example, pressurized nitrogen or pressurized carbon dioxide. It is noted that the number of closed loops of the device 20 or 80 is linked to the number of turbines of the generator set 21, as explained above.

[0094] It is noted that there may be, in the cold recovery device, a number of closed loops less than the number of turbines, for example by providing a cooling tower to heat the cryogenic fluid before a third turbine. It is also possible to have two closed loops and, on one of the loops (preferably on the loop involving the pump system 64), to add at least one (preferably two for freezing reasons) heat exchanger with an ambient fluid before the inlet of the third turbine and before the return to the thermal energy storage tanks.

[0095] It is also possible to have a cascade of more than one turbine on the same loop, the only limit being the pressure drop and the economic cost. It should be noted, in this regard, that the embodiments of the device which is the subject of the invention described above allow the implementation of such cascades, because, on a closed loop, the loop can be pressurized to take into account the pressure drops.

[0096] During the power supply shutdown, the cryogenic liquid stored in the tank 24 is pumped and compressed by the cryogenic pump 25. This compressed liquid is gasified and heated by the upstream heat exchanger 26. This compressed gas is then partially expanded by the high-pressure turbine 29 to provide electricity and cold. Next, this expanded cold gas is heated by the downstream heat exchanger 32, then expanded by the low-pressure turbine 36 to provide electricity and cold. The gas leaving the turbine 36 is still very cold and is used to partially cool customer 23.

[0097] It is noted that the energy supplied to evaporate and heat the cryogenic liquid comes from the thermal energy storage system 60, 61 and 62. The second hot heat transfer fluid (HTF) coming from the thermal energy storage system 60, 61 and 62 is conveyed by the pump 63 to the upstream heat exchanger 26. By passing through the upstream heat exchanger 26, the second hot heat transfer fluid gives up its heat and recovers the cold energy from the cryogenic liquid. Then, this second cooled heat transfer fluid passes through the thermal energy storage system 60, 61 and 62 to be heated and start a new loop. The thermal energy storage system 60, 61 and 62 then stores the cold which is used later.In the same way, the second hot heat transfer fluid from the thermal energy storage tanks 60, 61 and 62 heats the first cold fluid compressed through the downstream heat exchanger 32 and recovers cold. This second cooled heat transfer fluid is heated by passing through the heat exchanger 70 connected to the customer 23. In this way, the customer 23 is cooled and the heat from the customer 23 is recovered to be used to generate electricity. This second hot heat transfer fluid is mixed with the cold heat transfer fluid from the upstream heat exchanger 26 and then heated by passing through the thermal energy storage system 60, 61 and 62 to start a new loop. This cold stored by the thermal energy storage system 60, 61 and 62 is used later.

[0098] After a power outage, the cold stored by the thermal energy storage system 60, 61 and 62 is used to cool the customer 23 in the following manner: the second cold heat transfer fluid is removed from the thermal energy storage system 60, 61 and 62 to be sent to the heat exchanger 70 connected to the customer 23 where it is heated by the heat from the Data Center. The second heated heat transfer fluid is cooled by the thermal energy storage system 60, 61 and 62 to begin a new cooling cycle. In this way, the thermal energy storage system 60, 61 and 62 stores the heat of the customer 23 for use during the next electricity production.

[0099] In a tropical climate or during a hot period, it may be useful to superheat the second heat transfer fluid. This can be easily achieved by using the heat exchanger 52 coupled to the tower 51. This increase in temperature reduces the mass flow rate of cryogenic liquid required for electricity generation.

[0100] In one embodiment of the cold recovery device 20 or 80, an average mass flow rate of 7 kg.s 1 is necessary to cool the client 23 after the power supply has been cut off, or in the event of the cryogenic liquid being exhausted. This mass flow rate is linked to the cold temperature of the thermal energy storage system. 60, 61 and 62. The cold temperature is approximately -107 °C. This temperature results from the mixing of fluid at -170 °C with a mass flow rate of 14 kg.s 1 coming from the upstream heat exchanger 26 and fluid at 2 °C with a mass flow rate of 8 kg.s 1 coming from the loop passing through the heat exchanger 70.

[0101] The hot temperature that can be extracted from the customer's cooling system 23 after the failure is set at 5°C. This temperature can be increased if the ambient temperature is higher than 5°C by passing through the ambient heat exchanger 52 coupled to the tower 51.

[0102] The capacity of the thermal energy storage system 60, 61 and 62 is estimated based on the mode of use of the generator set 21. For continuous operation for 24 hours, the energy to be stored is approximately 44 MWh. If the thermal energy storage system 60, 61 and 62 is composed of magnetite for example, the overall volume required is approximately 1050 m3 with a vacuum of 40%. Other storage technologies are, of course, possible. A combination of phase change materials can reduce the required volume since their thermal capacities are greater than those of solid materials such as rock. Finally, chemical storage can be used since long periods can be observed between power supply failures.

[0103] The cold recovery device 20 or 80, associated with a cold cogeneration generator set 21 producing electricity from a cryogenic fluid, makes it possible to recover the cold from the liquid gasification process, to store all or part of this cold and to return it to a customer 23, including outside the electricity production phases. Simultaneously, the cold recovery device 20 or 80 provides heat to the electricity production system. This stored heat may come from the customer's hot thermal discharges, from the ambient air or from any other thermal source, fatal or not.

[0104] The cold recovery device 20 or 80 is composed of one or more thermal energy storage tanks, one or more pumps, and at least one connection point with the customer 23. These thermal energy storage tanks, these rotating machines (pumps, fan or compressor) allowing the circulation of a heat transfer gaseous fluid and the customer 23 are interconnected in a closed and pressurized circuit.

[0105] Simultaneously, the cold recovery device 20 or 80, connected to the upstream 26 and downstream 32 heat exchangers of the cold cogeneration generator set 21, provides the heat required by the electricity production process and delivers the cold thus recovered to the customer 23 or stores it in thermal energy storage tanks 60, 61 and 62, if the quantity of cold recovered is greater than the cold demand of the customer 23.

[0106] To take into account the case where the quantity of frigories generated during the duration of electricity production may exceed the capacity of the thermal energy storage tanks 60, 61 and 62, fluid / ambient air exchangers 77 are associated in parallel with these tanks 60, 61 and 62, preferably at least two in number in order to be able to treat the icing of one of these exchangers 77.

[0107] During a power outage, the cold cogeneration generator set 21 and the cold recovery device 20 or 80 operate to supply electricity and cold to the customer 23. At the outlet of the low pressure turbine 36, the gas resulting from the change of state of the cryogenic liquid reaches the desired pressure, ambient pressure or slightly higher if a silencer system or a connection to the customer, or a cold recovery loop for needs other than the cold recovery device 20 or 80, is added.

[0108] When the electrical current returns to the network, the electricity production system stops and the customer's electrical consumption switches back to the electrical network. The cold recovery system ensures the continuity of cold supply to the customer 23 by releasing the cold from the thermal energy storage tanks and by switching the electrical consumption of each pump 63 and 64 to the electrical network: each pump 64 which made it possible to supply cold to the customer 23 during the power outage continues to operate while each other pump of the cold recovery device 20 or 80, for example the pump 63, is stopped.The system then constitutes a closed circuit composed of the thermal energy storage tanks 60, 61 and 62, the pump 48 connected to the cooling unit 45 of the system 22 for supplying cold to the customer 23 and, possibly, a connection to the heat exchanger 52 connected to the tower 51 in order to recover heat from the environment, if necessary, or any other source of fatal heat from the customer.

[0109] In a first configuration, the second fluid is extracted from the thermal energy storage tanks 60, 61 and 62 and is sucked in by a pump 64 slightly compressing the second fluid. This second fluid is directed towards the heat exchanger 70 interfacing with the cold supply system 22, within which it heats up by recovering the heat coming from the customer 23 and giving up its cold to the latter. The second fluid thus heated possibly passes through the heat exchanger 52 interfacing with the cold supply system 22 connected to a hot source, for example the tower 51, in order to be superheated there. This second superheated fluid passes into the thermal energy storage tanks 60, 61 and 62 in order to be cooled there while giving up its heat which is thus stored. The second fluid is then ready for a new cooling cycle of the customer 23.

[0110] Alternatively, as illustrated in Figures 8 and 9, if the temperature of the second fluid in the thermal energy storage tanks 60, 61 and 62, is not compatible with the specifications of the pump 64, the second fluid extracted from the thermal energy storage tanks 60, 61 and 62, is directly directed from the tanks 60, 61 and 62 to the heat exchanger 70 and, optionally, to the heat exchanger 52, interfacing with the cold supply system 22, before passing through the pump 64.

[0111] In the case of multiple thermal energy storage tanks, one moves from one tank to another once the previous tank is “empty”, that is to say there is no more cold within this tank.

[0112] Variants of the device that is the subject of the invention are described below. In variants, the fluid circulating in the device 20 or 80 is another gas that does not pass into the liquid phase in the method described, depending on the operating temperatures. For example, this gas is nitrogen, dry air, carbon dioxide CO2 or argon. In variants, the restitution of the cold to the customer 23 is done by means of a heat exchanger directly connected with the cold circuit of the customer 23, without cold supply system 22. In variants, at least one (preferably at least two due to the risks of frost explained above) heat exchanger 77 with the ambient air, for example an air cooling tower, is added to the device 20 or 80, in parallel with the thermal energy storage tanks 60, 61 and 62, to dissipate the excess cold produced when the thermal energy storage tanks 60, 61 and 62 are saturated.

[0113] In variants, a heat exchanger with a fatal thermal source or a geothermal energy source is added to the device 20, to heat the cryogenic fluid when the thermal energy storage tanks are at their lowest temperature. Statement of the invention

[0114] The present invention aims to remedy all or part of the drawbacks of the prior art. To this end, according to a first aspect, the present invention aims at a device for recovering colds, between: - a cold cogeneration generator set comprising a source of cryogenic liquid, at least one primary heat exchanger heating a first fluid from the source of cryogenic liquid and cooling a second fluid when the cold cogeneration generator set supplies electricity, each said primary heat exchanger supplying gas from the first fluid under pressure to at least one turbine associated with a generator, on the one hand, and - a unit of frigories consumption using a third fluid as heat transfer fluid, on the other hand.

[0115] This device comprises: - at least one thermal energy storage tank configured to store, when the cold cogeneration generator set supplies electricity, frigories carried by the second fluid, on a closed-loop pipe circuit passing through at least one primary heat exchanger of the cold cogeneration generator set and comprising at least one pump, and - at least one secondary heat exchanger, between the pipe circuit through which the second fluid flows and the cold consumption unit, configured to supply cold to the cold consumption unit when the cold cogeneration generator set is not supplying electricity and a pump in the pipe circuit is operating and extracting cold from at least one thermal energy storage tank.

[0116] Thanks to these provisions, frigories generated in excess of the customer's needs, during the production of electricity, are stored, then supplied to the customer once the production of electricity is no longer necessary, so that the customer's energy consumption is reduced. The overall energy efficiency of the device is thus higher than it would be in the absence of frigories storage.

[0117] In embodiments, the cold cogeneration generator set comprises at least two primary heat exchangers, and the closed-loop piping circuit comprises: - a first loop passing through a pump, through an upstream primary heat exchanger and through at least one thermal energy storage tank and - a second loop passing through a pump, through a downstream primary heat exchanger, through at least one secondary heat exchanger and through at least one thermal energy storage tank.

[0118] Thanks to these provisions, the first loop is dedicated to the storage of frigories in the thermal energy storage tanks, while the second loop transfers, during the electricity production phase, frigories from the cold cogeneration generator set to the customer and to these tanks, then transfers, when the electricity production is stopped, frigories from the thermal energy storage tanks to the customer.

[0119] In embodiments, the second loop comprises an upstream secondary heat exchanger configured to supply frigories to the frigories consumption unit and a downstream secondary heat exchanger configured to reheat the second fluid exiting the upstream secondary heat exchanger when the cold cogeneration generator set is not supplying electricity.

[0120] Thanks to these arrangements, the fluid stored in the thermal energy storage tanks can be heated more quickly, in order to promote the efficiency of the electricity production when this production is needed.

[0121] In embodiments, the cold recovery device comprises a mixer common to the loops of the pipe circuit, configured so that, when the cold cogeneration generator set supplies electricity, the inlet temperature of the thermal energy storage tanks is stabilized.

[0122] This reduces the thermal shocks suffered by the thermal energy storage tanks.

[0123] In embodiments, the cold cogeneration generator set comprises at least two primary heat exchangers, and the closed-loop piping circuit comprises, when the cold cogeneration generator set is operating, a first loop passing through a pump, through an upstream primary heat exchanger and through at least one thermal energy storage tank and a second loop passing through a pump, through a downstream primary heat exchanger, through at least one secondary heat exchanger, without passing through a thermal energy storage tank.

[0124] Thanks to these provisions, the first loop is dedicated to the storage of frigories in the thermal energy storage tanks, while the second loop is dedicated to the transfer, during the electricity production phase, of frigories from the cold cogeneration generator set to the customer, then, when the electricity production is stopped, to the transfer of frigories from the thermal energy storage tanks to the customer.

[0125] In embodiments, the cold recovery device comprises at least two thermal energy storage tanks, and a multi-way valve configured so that, in turn, a single thermal energy storage tank is traversed by the second fluid in motion, when the cold cogeneration generator set is not supplying electricity and a pump of the pipe circuit is operating and extracting cold energy from at least one thermal energy storage tank.

[0126] The successive use of thermal energy storage tanks when delivering frigories to the customer facilitates thermal management and avoids possible preferential paths of the fluid in these tanks causing a thermal imbalance between them. Indeed, if several tanks are used simultaneously in parallel, the same flow rate and the same pressure drop in these tanks cannot be guaranteed. This can introduce thermal instabilities that must be managed subsequently. For example, after a certain number of cycles, it would no longer be possible to store or release frigories in a tank and it would then be necessary to reset the frigory storage system.

[0127] In embodiments, the cold recovery device comprises, in parallel with at least one thermal energy storage tank, a heat exchanger heat between the second fluid and a fatal heat source, for example the ambient air.

[0128] Thanks to these provisions, when the production of electricity has caused the saturation of frigories in the thermal energy storage tanks, the excess frigories are absorbed by this heat exchanger mounted in parallel with at least one of these tanks.

[0129] In embodiments, at least one secondary heat exchanger, between the pipe circuit traversed by the second fluid and the cold consumption unit, is configured to: - receive frigories from the frigory consumption unit when the cold cogeneration generator set is not supplying electricity and a pump in the pipeline circuit is operating and - store these colds in at least one thermal energy storage tank.

[0130] Thanks to these arrangements, excess cold produced by the customer's cold unit can be stored in the thermal energy storage tanks for later restitution, for example when the cost of producing cold by the customer's cold unit has increased.

[0131] According to a second aspect, the present invention relates to a device for producing electricity and supplying cold, which comprises the cold cogeneration generator set and the cold recovery device which is the subject of the first aspect of the invention.

[0132] The advantages, aims and particular characteristics of this device for producing electricity and supplying cold being similar to those of the cold recovery device which is the subject of the invention, they are not recalled here.

[0133] In embodiments, the device for producing electricity and supplying cold comprises a heat exchanger between a gas coming from an outlet of the cold cogeneration generator set, and a cooling fluid of the cold consumption unit.

[0134] According to a third aspect, the present invention aims at a method for recovering frigories, between: - a cold cogeneration generator set comprising a source of cryogenic liquid, at least one primary heat exchanger heating a first fluid from the source of cryogenic liquid and cooling a second fluid when the cold cogeneration generator set supplies electricity, each said primary heat exchanger supplying gas from the first fluid under pressure to at least one turbine associated with a generator, on the one hand, and - a frigories consumption unit using a third fluid as a heat transfer fluid, on the other hand;

[0135] This method comprises: - a step of supplying electricity by the cold cogeneration generator set comprising a step of storing cold energy carried by the second fluid in at least one thermal energy storage tank on a closed-loop pipe circuit passing through at least one primary heat exchanger of the cold cogeneration generator set and comprising at least one pump, and - a step of stopping the supply of electricity by the cold cogeneration generator set comprising a step of operating a pump of the pipe circuit and extracting cold from at least one thermal energy storage tank and supplying cold to the cold consumption unit, by at least one secondary heat exchanger between the pipe circuit through which the second fluid flows and the cold consumption unit.

[0136] The advantages, purpose and particular characteristics of this method being similar to those of the cold recovery device which is the subject of the invention, they are not recalled here.

Claims

Claims

1. Device (20, 80, 90, 100) for recovering cold, between: - a cold cogeneration generator set (21, 91) comprising a source of cryogenic liquid (24), at least one primary heat exchanger (26, 32) heating a first fluid coming from the source of cryogenic liquid and cooling a second fluid when the cold cogeneration generator set supplies electricity, each said primary heat exchanger supplying gas from the first fluid under pressure to at least one turbine (29, 36) associated with a generator (30, 37), on the one hand, and - a unit (22, 23) for consuming frigories using a third fluid as heat transfer fluid, on the other hand; characterized in that it comprises: - at least one thermal energy storage tank (60, 61, 62) configured to store, when the cold cogeneration generator set supplies electricity, frigories carried by the second fluid, on a circuit of pipes (65, 67, 69) in a closed loop passing through at least one primary heat exchanger (26, 32) of the cold cogeneration generator set and comprising at least one pump (63, 64), and - at least one secondary heat exchanger (70), between the pipe circuit traversed by the second fluid and the cold consumption unit, configured to supply cold to the cold consumption unit when the cold cogeneration generator set is not supplying electricity and a pump (64) of the pipe circuit is operating and extracting cold from at least one thermal energy storage tank.

2. Device (20, 90) according to claim 1, in which the cold cogeneration generator set (21) comprises at least two primary heat exchangers (26, 32), and in which the closed-loop pipe circuit (65, 67, 69) comprises: - a first loop passing through a pump (63), through an upstream primary heat exchanger (26) and through at least one thermal energy storage tank (60, 61, 62) and - a second loop passing through a pump (64), through a downstream primary heat exchanger (32), through at least one secondary heat exchanger (52, 70) and through at least one energy storage tank thermal.

3. Device (20, 90) according to claim 2, in which the second loop comprises an upstream secondary heat exchanger (70) configured to supply frigories to the frigories consumption unit (22, 23) and a downstream secondary heat exchanger (52) configured to heat the second fluid leaving the upstream secondary heat exchanger when the cold cogeneration generator set is not supplying electricity.

4. Device (20, 90) according to one of claims 2 or 3, which comprises a mixer (74, 85) common to the loops of the pipeline circuit, configured so that, when the cold cogeneration generator set (21) supplies electricity, the temperature at the inlet of the thermal energy storage tanks (60, 61, 62) is stabilized.

5. Device (80) according to claim 1, wherein the cold cogeneration generator set (21) comprises at least two primary heat exchangers (26, 32), and wherein the closed-loop pipe circuit (65, 67, 69) comprises, when the cold cogeneration generator set (21) is operating, a first loop passing through a pump (63), through an upstream primary heat exchanger (26) and through at least one thermal energy storage tank (60, 61, 62) and a second loop passing through a pump (64), through a downstream primary heat exchanger (32), through at least one secondary heat exchanger (70), without passing through a thermal energy storage tank.

6. Device (20, 80, 90), according to one of claims 1 to 5, which comprises at least two thermal energy storage tanks (60, 61, 62), and a multi-way valve (68) configured so that, in turn, a single thermal energy storage tank is traversed by the second fluid in motion, when the cold cogeneration generator set is not supplying electricity and a pump (64) of the pipe circuit is operating and extracting frigories from at least one thermal energy storage tank.

7. Device (20, 80, 90, 100) according to one of claims 1 to 6, which comprises, in parallel with at least one thermal energy storage tank (60, 61, 62), a heat exchanger (77) between the second fluid and a fatal heat source, for example ambient air.

8. Device (20, 80, 90, 100) according to one of claims 1 to 7, in which at least one secondary heat exchanger (70), between the circuit of pipes traversed by the second fluid and the cold consumption unit (23), is configured to - receive cold from the cold consumption unit (22, 23) when the cold cogeneration generator set is not supplying electricity and a pump (64, 92) of the pipe circuit is operating and - store these cold in at least one thermal energy storage tank (60, 61, 62).

9. Device (20, 21, 80, 90, 100) for producing electricity and supplying cold, which comprises the cold cogeneration generator set (21, 91) and the cold recovery device (20, 80, 90, 100) according to one of claims 1 to 8.

10. Device (20, 21, 80, 90) according to claim 9, which comprises a heat exchanger (72) between a gas coming from an outlet (41) of the cold cogeneration generator set (21), and a cooling fluid of the cold consumption unit (23).

11. Method (120) for recovering cold energy, between: - a cold cogeneration generator set (21, 91) comprising a source of cryogenic liquid (24), at least one primary heat exchanger (26, 32) heating a first fluid coming from the source of cryogenic liquid and cooling a second fluid when the cold cogeneration generator set supplies electricity, each said primary heat exchanger supplying gas from the first fluid under pressure to at least one turbine (29, 36) associated with a generator (30, 37), on the one hand, and - a unit (22, 23) for consuming cold energy using a third fluid as a heat transfer fluid, on the other hand;characterized in that it comprises: - a step (104) of supplying electricity by the cold cogeneration generator set simultaneously with a step (105) of storing frigories carried by the second fluid in at least one thermal energy storage tank (60, 61, 62) on a closed-loop pipe circuit (65, 67, 69) passing through at least one primary heat exchanger (26, 32) of the cold cogeneration generator set and comprising at least one pump (63, 64), and - a step (106) of stopping the supply of electricity by the cold cogeneration generator set comprising a step (109) of operating a pump (64) of the pipe circuit and extraction; of frigories from at least one thermal energy storage tank and supply of frigories to the frigory consumption unit, by at least one secondary heat exchanger (70) between the pipe circuit traversed by the second fluid and the frigory consumption unit.

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