EP4702292A1

EP4702292A1 - Fluid cooling plant and refrigerant module thereof

Info

Publication number: EP4702292A1
Application number: EP24725049.1A
Authority: EP
Inventors: ALessandra GIANNASI
Original assignee: Nuovo Pignone Technologie SRL
Current assignee: Nuovo Pignone Technologie SRL
Priority date: 2023-04-28
Filing date: 2024-04-26
Publication date: 2026-03-04
Also published as: CN120936843A; WO2024223085A1; MX2025012589A; AU2024264447A1; KR20250170706A

Abstract

A fluid cooling plant to cool and liquefy a fluid, like a hydrogen, is disclosed. The fluid cooling plant comprises a first cooling stage, and a second cooling stage, connected to the first cooling source. The first cooling stage has a cold source and a heat exchanger, to cool the ambient temperature hydrogen gas. The cold source is liquid natural gas but not only, which is gasified by ambient temperature hydrogen so that the hydrogen is cooled down. The second cooling stage is made of one or more refrigerant modules, whose operation is based on a magnetocaloric material. Also disclosed is an operating method of the refrigerant modules.

Description

Fluid Cooling Plant and Refrigerant Module thereof

Description

TECHNICAL FIELD

[0001] The present disclosure concerns a fluid cooling plant capable of recovery energy to cool down a fluid like hydrogen or any other gas or fluid in general.

BACKGROUND ART

[0002] In modem industry, certain kinds of gases, such as hydrogen or helium, which liquefy at very low temperatures, are necessary in some specific applications. However, to bring the hydrogen or Helium to the liquid stage a large amount of energy is required. Liquid hydrogen is also necessary to deploy the global energy transition. Thus, lowering the price of liquid technical gases (LH2 LN2, He) production, in view of the energy demand, would key enabler of the above energy transition.

[0003] The hydrogen liquefies at a temperature of around 20K (-253°C), and helium at 4K (-269°C), and both are used for nuclear energy plant cooling, or for allowing the transition of some specific materials to the superconducting stage.

[0004] Also, recovering energy is currently of maximum importance. In fact, energy is expensive, and the demand is increasing, then preventing any waste has become an industrial and plant design trend.

[0005] In this connection, there is the need to recover cold energy. Fig. I, for instance, shows how cold energy reuse can be obtained. Cold energy utilization e.g. coming from the Liquid Natural Gas (LNG) can be used for the air conditioning, the desalinization of the seawater, in the cold chain, to be stored, the regasification of industrial plants, natural gas liquid recovery, capturing CO2, to freeze desalinization, for separating fluids, or to generate cryogenic power, to name a few.

[0006] To lower the temperature of the hydrogen or similar fluids, the Claude or Brayton cycle is typically used, which is usually energy-consuming.

[0007] Currently, other technologies are employed to cool the hydrogen or other fluids, such as those disclosed in the European patent application EPl 156287, or the US patent application US20220115680. However, although such solutions allow recovery of energy, they do not reach a remarkable efficiency to liquefy the hydrogen.

[0008] Accordingly, an improved cooling system, to liquefy fluids or gases like hydrogen, helium, or the like, so as to save energy, would be welcomed in the technology.

[0009] It would be desirable to provide also an improved plant capable of liquefying fluids like hydrogen or helium, which can be modular and with a reduced footprint if compared to those of the prior art.

[0010] Relevant prior art includes the US patent application US2022/115680A1 and the European patent application EP4006189A1.

SUMMARY

[0011] The cold source is key, joined with the lower energy demand of magnetocaloric liquefaction with respect to the Claude and Brayton cycles, to reduce further the energy demand (LNG is an example of cold source).

[0012] In one aspect, the subject matter disclosed herein is directed to a fluid cooling plant having a first cooling stage, provided with a cold source, a heat exchanger, connected to the cold source, and a fluid transporting pipe through which the fluid to be cooled, such as hydrogen, is delivered. The fluid transporting pipe, is connected to the heat exchanger and the fluid to be cooled is put in thermal contact with the cold source by means of the heat exchanger, so that the temperature of the fluid is cooled. The cold source is a re-gasification plant, for gasifying liquid gas, so the liquid gas operates as the cold source, which cools the fluid when in thermal contact with it and re-gasifies at the same time.

[0013] In another aspect, the subject matter disclosed herein concerns a second cooling source, connected to the first cooling source, to cool the fluid to be cooled by the first cooling stage to a target temperature.

[0014] In another aspect, disclosed herein is a fluid cooling plant equipped with a pipeline connected to the heat exchanger, wherein the gasified fluid is expelled from the first cooling stage for its usage. [0015] In one aspect, the subject matter disclosed herein is directed to the fact that the second cooling stage comprises refrigerant modules, arranged in a cascade. Each refrigerant module comprises a magnetic field source, and a magnetocaloric material, such as Holmium, arranged so as to be subject to the magnetic field generated by the magnetic field source. The refrigerant module comprises also an inlet pipe, for transporting a fluid to be put in thermal contact with the magnetocaloric material, and an outlet pipe, for transporting a fluid after being in thermal contact with the magnetocaloric material. The magnetic field source comprises a permanent magnet or an electromagnetic magnet, driven by an electronic circuit to switch on and off the magnetic field, and adjust the magnetic field generated.

[0016] In another aspect, the subject matter disclosed herein is directed to a method of operating the fluid cooling plant disclosed above. The method comprises the following steps: receiving and storing the liquid natural gas; bringing the fluid to be cooled in thermal contact with the liquid natural gas by means of the heat exchanger, so that the temperature of the fluid is cooled. Also, the fluid to be cooled is hydrogen.

[0017]

The method comprises the following steps: using the cold source as this from Air separation units involving cryogenic fluids; bringing the fluid to be cooled in thermal contact with the cryo-fluids in the Air separation plant as by means of the heat exchanger, so that the temperature of the fluid is cooled. Also, the fluid to be cooled is hydrogen, or helium.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] A more complete appreciation of the disclosed embodiments of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

Fig. 1 illustrates a schematic of the utilization of the cold energy utilization according to the prior art;

Fig. 2 illustrates a scheme of a recovery plant according to a first embodiment. Fig. 3 illustrates an operating cycle of the operation of a magnetocaloric material.

Fig. 4 illustrates a flow chart showing the operating method of a refrigerant module based on a magnetocaloric material;

Fig. 5 illustrates a refrigerant module based on a magnetocaloric material, according to a first embodiment, in a magnetization operating step;

Fig. 6 illustrates the refrigerant module of figure 5 in a magnetocaloric material cooling operating step;

Fig. 7 illustrates the refrigerant module of figure 5 in a demagnetization operating step; and

Fig. 8 illustrates the refrigerant module of figure 5 in a fluid refrigerant operating step;

Fig. 9 illustrates the temperature dependence of magnetization of polycrystalline Holmium under different applied magnetic fields;

Fig. 10 illustrates the isothermal entropy change of poly crystalline Holmium induced by a magnetic field variation;

Fig. 11 illustrates a comparative graph of the isothermal entropy change resulting from magnetic field variations; and

Fig. 12 illustrates a reversible adiabatic temperature change of polycrystalline Holmium measured as a function of temperature with a magnetic field variation.

DETAILED DESCRIPTION OF EMBODIMENTS

[0019] The liquefaction of certain fluids is crucial for several hi-tech applications, either for scientific research, or industrial applications. According to one aspect, the present subject matter is directed to a cooling plant capable of liquefying hydrogen or similar gases, by recovering energy from cold sources, like liquid natural gas (LNG, or Ethylene purification process, cryo-treatments with LN2, Air Separation plants etc..), which, as it is known, is transported at very low temperatures. Ambient temperature hydrogen is therefore used to gasify the liquid natural gas, achieving a low-temperature hydrogen with the cold energy that would be instead wasted using the gasification procedure of the prior art.

[0020] According to another aspect, the present subject matter is also directed to cooling modules for reducing the temperature of the hydrogen, based on the technology and the phenomena of magnetocaloric materials, exploiting the physical properties of such materials when subject to a magnetic field. The hydrogen or any other materialfluid can be cooled by applying a magnetic field to such magnetocaloric materials, which thus changes their temperature. Applying a proper cycle, the hydrogen can be incrementally cooled, achieving the desired temperature in an efficient, easily controlled, and compact way.

[0021] In the various figures, similar parts will be indicated by the same reference numbers.

[0022] Referring now to the drawings, Fig. 2 shows a schematic view of a fluid cooling plant, wholly indicated with the reference numeral 1, according to a first embodiment. The fluid cooling plant 1 is intended to liquefy hydrogen (H2). In other embodiments, the fluid to be cooled can be different from hydrogen. For instance, the fluid cooling plant 1 can be used to cool or liquefy helium or nitrogen.

[0023] The fluid cooling plant 1 comprises essentially a first cooling stage 2, and a second cooling stage 3, arranged in series and downstream to the first cooling stage 2. The first 2 and the second 3 cooling stages reduce the temperature of a mass of hydrogen (H2). The second cooling stage 3 cools down the hydrogen previously cooled by the first cooling stage 2.

[0024] The fluid cooling plant 1 can comprise only the first cooling stage 2, without the additional second cooling stage 3, to further cool the hydrogen out of the first cooling stage 2. The addition of the second cooling stage 3 depends on the fluid to be cooled or liquefied. For instance, to cool or liquefy the propane the second cooling stage 3 is not required. Therefore, the fluid cooling plant 1 is modular and can be realized according to the cooling needs.

[0025] The first cooling stage 2 comprises a cold source 21 for cooling the fluid to be cooled. In the present embodiment, the cold source is an LNG gasification stage 21, but in other embodiments, it can be a different cold source. In the LNG re-gasification stage, the liquid natural gas (LNG) is received at a temperature of 11 IK (around - 162°C), which is the temperature at which the LNG is kept liquid and so can be transported.

[0026] The LNG gasification stage 2 comprises a container 211, where the LNG is deposited and stored. In the container 211 the LNG is at a temperature of -162°C. In such conditions, the LNG operates as a cold source. The LNG has to be wormed up to be re-gasified.

[0027] The LNG gasification stage 2 also comprises a heat exchanger 22, where the LNG is warmed by contact with the hydrogen H2. The hydrogen is supplied to the heat exchanger 22 through a fluid transporting pipe 23. One or more pumps (not shown in the figure) can be foreseen to supply the hydrogen to be cooled to the heat exchanger 22 through the fluid transporting pipe 23. The hydrogen has a very tiny molecule, so the transporting pipe 23 is appropriately sealed.

[0028] The hydrogen is at ambient temperature, and it is then put in thermal contact with the liquid natural gas, by means of a heat exchanger 22, as mentioned above. The LNG is then brought re-gassified, after the heat exchange with the hydrogen. The LNG changes its state from liquid to gaseous and then it is introduced into a pipeline 24, to be burnt and/or used for energy production, e.g. by a gas turbine or the like.

[0029] The temperature of the hydrogen H2 is then lowered from ambient temperature to a temperature of around -160°C, namely around the temperature of the LNG exchanging the heat in the heat exchanger 22.

[0030] In terms of energy recovered, in general, the natural gas when liquefied (LNG) has a temperature of -161.5°C. The liquid-gas phase transition requires 800 kJ/kg, while H2 liquefaction requires about 4900 kJ/kg. The 16% of the energy demand to produce LH2 will come from the LNG regasification. In the prior art plants, such energy would be wasted, while additional energy would be required to bring the hydrogen from ambient temperature to a temperature of around -160°C. In other words, by means of the first cooling stage 2, which uses gaseous hydrogen, to be liquefied, the LNG wasted cold is recovered, saving energy and increasing the overall efficiency of hydrogen liquefaction process.

[0031] The hydrogen, now cooled down to a temperature of around -160°C, is then further cooled by one or more refrigerant modules 31 of the second cooling stage 3, which lowers the hydrogen H2 temperature to a target temperature, which, in the embodiment shown, is its liquefaction temperature, namely around -253°C. Therefore, the second cooling stage 3 lower the temperature of the hydrogen from -160°C to -253 c.

[0032] The second cooling stage 3 comprises several magnetic refrigerant modules 3 la - 3 Id, arranged in series, or cascade, to further cool the hydrogen H2 cooled by the previous module. In particular, the first refrigerant module 3 la lowers the temperature of the hydrogen H2 from the temperature of around -160°C (T₁) to T_{2 i} the second refrigerant module 3 lb lowers the temperature of the hydrogen H2 from the temperature of T₂ to T₃; the third refrigerant module 31c lowers the temperature of the hydrogen H2 from the temperature of T₃ to T₄; and the fourth refrigerant module 3 Id lowers the temperature of the hydrogen H2 from the temperature of T₄, and then 7) (7) = T final) to the target temperature, namely around -253 °C, namely the temperature at which the hydrogen makes a transition from gas to liquid.

[0033] Depending on the fluid to be cooled and the target temperature to be reached, the number of the refrigerant module 31 can be different. In some embodiments, the second cooling stage 3 can be even made of just one refrigerant module 31.

[0034] Each refrigerant module 31 operates by exploiting the properties of the magnetocaloric material.

[0035] Specifically, each refrigerant module 31 operates by using Holmium as magnetocaloric material, even more specifically by using Polycrystalline Holmium. The Holmium, specifically Polycrystalline Holmium, like other magnetocaloric materials, shows magnetocaloric effects. The magnetocaloric effect (MCE) is the physical property for which, the material heats or cools when subject to an applied magnetic field, or when a magnetic field changes. The phenomenon is based on the coupling between the magnetic moments and the external magnetic field. In some cases, the MCE involves structural transitions caused by magnetic transitions.

[0036] In other embodiments, other magnetocaloric materials can be used, different from Holmium or Polycrystalline Holmium.

[0037] Each magnetic refrigerant module 31 comprises a magnetic field source 311, which can be a permanent magnet or an electromagnetic magnet, driven by an electronic circuit, not shown in the figure, to switch on and off the magnetic field, and adjust the magnetic field generated, and a magnetocaloric material MCM, which, in the present embodiment, is Polycrystalline Holmium. In other embodiments, the magnetocaloric material MCM can be made of other magnetocaloric materials. The magnetocaloric material MCM is arranged so as to be subject to the magnetic field generated by the magnetic field source 311.

[0038] The magnetic refrigerant module 31 also comprises an inlet pipe 312, for transporting a fluid to be put in thermal contact with the magnetocaloric material MCM, and an outlet pipe 313, for transporting a fluid after being in thermal contact with the magnetocaloric material MCM. The function of the inlet pipe 312 and the outlet pipe 313 is that of allowing a refrigerant fluid or the fluid to be cooled in thermal contact with the magnetocaloric material MCM, as better described in the following.

[0039] The operation of each magnetic refrigerant module 31 is schematically illustrated in Fig. 3, with reference also to Figs. 4, 5, 6, 7, and 8.

[0040] Referring to Figures 2 and 3, the magnetocaloric material MCM is shown at an initial temperature T_o and it is not magnetized. Such physical state is schematically represented by a set of randomly aligned arrows D, each one representing a magnetic dipole of the magnetocaloric material MCM.

[0041] In a magnetization step 41 of operating method 4, the magnetocaloric material MCM undergoes an adiabatic (namely isolated) magnetization by the permanent magnet or an electromagnet (not shown in the figure).

[0042] Due to the magnetocaloric properties of the magnetocaloric material MCM, the latter heats up, reaching a first temperature greater than the initial temperature T_o (so that 7 > To), while it is magnetized. Then, the magnetization effect is represented by the alignment of the magnetic moments, as said represented by the arrows D, aligned with the externally applied magnetic field. Since the magnetization in step 41 is adiabatic, the overall entropy of the magnetocaloric material MCM remains constant (Fig. 5).

[0043] Physically, magnetic entropy decreases while the thermal entropy correspondingly increases, since the molecules increase their kinetic energy. This causes the material to warm up.

[0044] In a magnetocaloric material cooling step 42, the magnetization is interrupted in particular the permanent magnet is removed, or the electromagnet is switched off. The magnetocaloric material MCM starts expelling heat (namely it is cooled), reducing its temperature. Being the system still isolated, the magnetic entropy increases and the thermal entropy reduces, thus causing the cooling down of the magnetocaloric material MCM, till around the initial temperature T_o.

[0045] The refrigerant fluid, typically helium, enters into the inlet pipe 312, cools down the magnetocaloric material MCM, and flows out (hot) out of the refrigerant module 31, through the outlet pipe 313. The helium or the refrigerant fluid, in general, is at a temperature lower than the first temperature 7 of the magnetocaloric material MCM (Fig. 6).

[0046] The magnetocaloric material MCM remains magnetized, as represented in the figure, where the arrows are aligned. In the figure, such a phenomenon is represented by the fact that the magnetic dipoles remain still aligned.

[0047] In a demagnetization step 43, the magnetocaloric material MCM is then subject to an adiabatic (i.e., isolated) demagnetization, thus reaching a second temperature T₂ lower than the initial temperature T_o (namely T₂ < T_o). Finally, in step 44, the gas to be cooled, namely the hydrogen, is further cooled. The hydrogen gas load Fb, in fact, is at a temperature TH2, which is higher than T2, so the magnetocaloric material MCM absorbs heat from the hydrogen FF, thus causing the lowering of the temperature. Referring to Fig. 7, the hydrogen enters the inlet pipe 312, is put in thermal contact with the magnetocaloric material MCM, and then flows out through the outlet pipe 313, to be introduced into the inlet pipe 312 of the following refrigerant module 31, if any, or, if it is the final refrigerant module 31 of the chain, namely, in the embodiment shown, the refrigerant module 3 Id, the hydrogen flowing out from the outlet pile 313 is taken for the required use.

[0048] By the cycle based on magnetocaloric material MCM, the hydrogen is cooled down to a target temperature, which in the case at issue is around -253°C, namely the liquefaction temperature. However, in other embodiments, the target temperature can be different.

[0049] Each refrigerant module 31 carries out the refrigerant cycle mentioned above in a cascade, thus gradually lowering the temperature of the hydrogen. [0050] It is noted that changing the process from the Claude cycle to the magnetocaloric multistage cycle would further reduce the energy demand. For instance, the Ingolstadt LH2 plant consumes 4.86 kWh/kgbh, while MCE-based liquefaction, in accordance with the plant of Fig. 2, takes 2.07 kWh/kgEE.

[0051] The fluid cooling plant 1 is capable of cooling the hydrogen down to the liquefaction temperature in a very efficient way, from one side, recovering cold wasted energy, using the hydrogen to be cooled to gasify the LNG (or N2 in case of an Air Separation UNIT) in the first cooling stage 2, and from the other side, in addition, the hydrogen is further cooled by the second cooling stage 3, by means of a set of refrigerant modules 31, whose number can be varied according to any necessity, exploiting the physical properties magnetocaloric materials, like the Polycrystalline Holmium.

[0052] Referring to Figures 9, 10, 11, and 12, there are shown graphs representing magnetic and magnetocaloric measurements of Holmium (Ho) polycrystal, when subject to magnetic fields with different intensities.

[0053] Specifically, Fig. 9 shows a graph in which the x-axis represents temperature, measured in Kelvin, while the y-axis represents the density of the magnetic field flux. The graph shows in particular the temperature dependence of magnetization of polycrystalline Ho under different applied magnetic fields (from 0.01 to 5 T), measured with temperature sweeps on heating (curve with circles) and on cooling (curve with squares).

[0054] Fig. 10 illustrates the isothermal entropy change of poly crystalline Ho induced by a magnetic field variation of 1 T, 2 T and 5 T. The entropy change is calculated from magnetization versus temperature data measured with temperature sweeps on heating (curve with circles) and on cooling (curve with triangles).

[0055] Fig. 11 shows a graph that compares the isothermal entropy change resulting from magnetic field variations of IT, 2T and 5 T in poly crystalline Ho (curve with triangles), with the corresponding change observed in single-crystal Ho sample when the magnetic field is applied along the (10-10) crystallographic direction (curve circles). Up to 2T the two crystalline forms could be considered equivalent. At 5T there is a slight difference in entropy variation. Being polycrystalline Ho preferrable in terms of manufacturability and equipment engineering, these results confirm its adoption in MCE cooling and liquefaction equipment.

[0056] Finally, Fig. 12 shows a reversible adiabatic temperature change of polycrystalline Ho measured as a function of temperature with a magnetic field variation of 1 T and 2 T. Temperature change is more sensitive to poly or single crystal forms variation.

[0057] Use of polycrystalline Holmium allows for a more efficient management of magnets (energy consumption) and manufacturability versus the single crystal holmium.

[0058] In another embodiment, the hydrogen’ s temperature is lowered by contact with liquid nitrogen (at the temperature of 77 K, which is that of liquid nitrogen) in the first cooling stage, where the cold Nitrogen is from an Air Separation Plants or Units.

[0059] In a more specific embodiment, the fluid cooling plant 1 comprises an air separation unit (not shown in the figures) to recover the cold in that air separation process. In fact, the air separation unit produces nitrogen N2 and oxygen O2, and other minor gases, through cryogenic processes. The air separation unit comprises a distiller, and the oxygen generated undergoes a liquid phase in said distiller. The oxygen has to be then regasified, acquiring energy and cooling the hydrogen, through the by means of a heat exchanger 22 or another by means of an additional heat exchanger.

ADVANTAGES

[0060] An advantage of the solution disclosed is that the fluid cooling plant is able to liquefy the hydrogen with a high degree of efficiency.

[0061] Another advantage of the present solution is that the second cooling stage can be modular and so it can be easily adapted to any industrial necessity and easily automated.

[0062] An additional advantage of the present solution is that of reducing energy demand in the hydrogen H2 liquefaction process, to allow for liquid hydrogen LH2 utilization and transportation in multipurpose processes. It has been also proven that magnetocaloric liquefaction is capable of strongly reducing the energy demand in comparison to the most applied method (Claude or Brayton cycles), which, combined with the energy recover gained by using the wasted “cold” in cold processes for example the regasification plant, allow to achieve high levels of energy efficiency.

[0063] Additional advantage is in the use of Polycrystalline Holmium instead of single crystal one due to the strong magnetic interaction for the Single crystal holmium with the moving magnetic field.

[0064] Additional advantage is in the use of the less expensive Polycrystalline Holmium.

[0065] Additional advantage is in the manufacturability of Polycrystalline Holmium versus single crystal (shaping the MCE material for cooling purpose).

[0066] While aspects of the invention have been described in terms of various specific embodiments, it will be apparent to those of ordinary skill in the art that many modifications, changes, and omissions are possible without departing from the spirt and scope of the claims. In addition, unless specified otherwise herein, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments.

[0067] Reference has been made in detail to embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. Reference throughout the specification to "one embodiment" or "an embodiment" or “some embodiments” means that the particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrase "in one embodiment" or "in an embodiment" or "in some embodiments" in various places throughout the specification is not necessarily referring to the same embodiment(s). Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

[0068] When elements of various embodiments are introduced, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

Claims

Fluid Cooling Plant and Refrigerant Module thereof CLAIMS

1. A fluid cooling plant (1) to cool a fluid, comprising: a first cooling stage (2) having a cold source (21), a heat exchanger (22), connected to the cold source (21), a fluid transporting pipe (23) through which the fluid to be cooled is delivered, a second cooling stage (3), connected to the first cooling source, to cool the fluid to be cooled by the first cooling stage (2) to a target temperature, wherein the fluid transporting pipe (23) is connected to the heat exchanger (22), wherein the fluid to be cooled is put in thermal contact with the cold source (21) by means of the heat exchanger (22), so that the temperature of the fluid is cooled, and wherein the cold source is a re-gasification plant (21), for gasifying liquid gas, so that the liquid gas operates as the cold source, which cools the fluid when in thermal contact with it and re-gasifies at the same time.

2. The fluid cooling plant (1) of claim 1, wherein the cold source is a re-gasification plant (21), for gasifying liquid natural gas, so that the liquid natural gas operates as the cold source, which cools the fluid when in thermal contact with it and gasifies at the same time.

3. The fluid cooling plant (1) of any one of the preceding claims, wherein the liquid natural gas (LNG) has a temperature of around -160°C.

4. The fluid cooling plant (1) of any one of the preceding claims, wherein the fluid is at ambient temperature, wherein ambient temperature depends on several parameters like storage, source, geographical location, before contacting the cold source (21).

5. The fluid cooling plant (1) of any one of the preceding claims, comprising a pipeline (24) connected to the heat exchanger (22), wherein the gasified fluid is expelled from the first cooling stage (2) for its usage.

6. The fluid cooling plant (1) of any one of the preceding claims, wherein the second cooling stage (3) comprises one or more refrigerant modules (31), arranged in a cascade.

7. The fluid cooling plant (1) of claim 6, wherein each refrigerant module (31) comprises a magnetic field source (311), a magnetocaloric material (MCM), arranged so as to be subject to the magnetic field generated by the magnetic field source (311), an inlet pipe (312), for transporting a fluid to be put in thermal contact with the magnetocaloric material (MCM), and an outlet pipe (313), for transporting a fluid after being in thermal contact with the magnetocaloric material (MCM).

8. The fluid cooling plant (1) of claim 7, wherein the magnetocaloric material (MCM) is Holmium.

9. The fluid cooling plant (1) of claim 8, wherein the Holmium is polycrystalline Holmium.

10. The fluid cooling plant (1) of any one of claims 7 or 8, wherein the magnetic field source (311) comprises a permanent magnet or an electromagnetic magnet, driven by an electronic circuit to switch on and off the magnetic field, and adjust the magnetic field generated.

11. The fluid cooling plant (1) of any one of the preceding claims, wherein the target temperature is equal or below the temperature in which the fluid liquefies.

12. The fluid cooling plant (1) of any one of the preceding claims, wherein the fluid to be cooled is hydrogen (H2).

13. The fluid cooling plant (1) of any one of the preceding claims, comprising an air separation unit, comprising a distiller, for producing nitrogen (N2) and oxygen (O2), through cryogenic processes, so that the oxygen generated undergoes a liquid phase in the distiller, to cool the hydrogen passing through the heat exchanger (22) of the first cooling stage (2) or an additional heat exchanger.

14. A method of operating the fluid cooling plant (1) according to any one of claims 2-13, comprising the following steps: receiving and storing the liquid natural gas (LNG); and bringing the fluid to be cooled in thermal contact with the liquid natural gas (LNG) by means of the heat exchanger (22), so that the temperature of the fluid is cooled.

15. The method of claim 14, wherein the fluid to be cooled is hydrogen (H2).

16. The method of any one of claims 14 or 15, comprising the step of bringing the fluid to be cooled in thermal contact with the nitrogen (N2) generated by an air separation gas by means of an heat exchanger (22), so that the temperature of the fluid is cooled.

17. A refrigerant module (31) for refrigerating a fluid, comprising: a magnetic field source (311); a magnetocaloric material (MCM), arranged so as to be subject to the magnetic field generated by the magnetic field source (311); an inlet pipe (312), for transporting a fluid to be put in thermal contact with the magnetocaloric material (MCM); and an outlet pipe (313), for transporting a fluid after being in thermal contact with the magnetocaloric material (MCM).

18. The refrigerant module (31) of claim 17, wherein the magnetocaloric material (MCM) is Holmium.

19. The refrigerant module (31) of claim 18, wherein the Holmium is polycrystalline Holmium.

20. The refrigerant module (31) of any one of claims 17 or 19, wherein the magnetic field source (311) comprises: a permanent magnet; or an electromagnetic magnet, driven by an electronic circuit to switch on and off the magnetic field, and adjust the magnetic field generated.

21. The refrigerant module (31) of any one of claims 17-20, wherein the fluid to be cooled is hydrogen (H2).

22. A method (4) of operating the refrigerant module (31) of any one of claims 17-21, comprising the following steps: a magnetization step (41), wherein the magnetocaloric material (MCM) is subject to a magnetic field by the magnetic field source (311), by the magnetic field source (311), so that the magnetocaloric material (MCM) passes from an initial temperature (T_o) to a first temperature (T₁), which is greater than the initial temperature (r_Q , a magnetocaloric material cooling step (42), wherein the magnetization of the magnetocaloric material (MCM) is removed, and the magnetocaloric material (MCM) is cooled up to around the initial temperature (T_o) by a refrigerant fluid entering into the inlet pipe (312) and coming out from the outlet pipe (313), wherein the refrigerant fluid is at a temperature lower than the first temperature (T₁) of the magnetocaloric material (MCM); a demagnetization step (43) of the magnetocaloric material (MCM) to reach a second temperature (T₂) lower than the initial temperature (T_o); and a fluid refrigerant step (44) wherein the fluid to be cooled enters the inlet pipe (312) to come in thermal contact with the magnetocaloric material (MCM), and then flows out through the outlet pipe (313), while the magnetocaloric material (MCM) is reported at the initial temperature (T_o), wherein the fluid to be cooled before entering the inlet pipe (312) has a fluid temperature (T_H2) higher than the second temperature (T₂).

23. The method (4) of claim 22, wherein the magnetization step (41) is carried out in an adiabatic way.

24. The method (4) of any one of claims 22 or 23, wherein the demagnetization step (43) is carried out in an adiabatic way.

25. The method (4) of any one of claims 22 - 24, wherein the gas to be cooled is hydrogen.