EP4386272A1 - Appareil et procédé d'humidification de gaz - Google Patents

Appareil et procédé d'humidification de gaz Download PDF

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Publication number
EP4386272A1
EP4386272A1 EP22306853.7A EP22306853A EP4386272A1 EP 4386272 A1 EP4386272 A1 EP 4386272A1 EP 22306853 A EP22306853 A EP 22306853A EP 4386272 A1 EP4386272 A1 EP 4386272A1
Authority
EP
European Patent Office
Prior art keywords
liquid
gas
heat exchange
exchange structure
flow passage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22306853.7A
Other languages
German (de)
English (en)
Inventor
Joël WYTTENBACH
Louison BOULIER
Alexandre DESCY
Gilbert-Gaëtan DESCY
Petrus Adrianus Joseph DONKERS
Sebastiaan Joannes Franciscus ERICH
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO
Original Assignee
Commissariat a lEnergie Atomique CEA
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commissariat a lEnergie Atomique CEA, Commissariat a lEnergie Atomique et aux Energies Alternatives CEA, Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO filed Critical Commissariat a lEnergie Atomique CEA
Priority to EP22306853.7A priority Critical patent/EP4386272A1/fr
Publication of EP4386272A1 publication Critical patent/EP4386272A1/fr
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F6/00—Air-humidification, e.g. cooling by humidification
    • F24F6/02—Air-humidification, e.g. cooling by humidification by evaporation of water in the air
    • F24F6/08—Air-humidification, e.g. cooling by humidification by evaporation of water in the air using heated wet elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F6/00—Air-humidification, e.g. cooling by humidification
    • F24F6/02—Air-humidification, e.g. cooling by humidification by evaporation of water in the air
    • F24F6/08—Air-humidification, e.g. cooling by humidification by evaporation of water in the air using heated wet elements
    • F24F6/10—Air-humidification, e.g. cooling by humidification by evaporation of water in the air using heated wet elements heated electrically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F25B39/04—Condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D5/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, using the cooling effect of natural or forced evaporation
    • F28D5/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, using the cooling effect of natural or forced evaporation in which the evaporating medium flows in a continuous film or trickles freely over the conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2110/00—Control inputs relating to air properties
    • F24F2110/40—Pressure, e.g. wind pressure

Definitions

  • the present invention relates to an apparatus and a method for humidifying a gas.
  • humidification usually refers to adding water vapor in a flow of air or other gases
  • the present invention is not limited to the use of water as liquid to evaporate.
  • the apparatus and method according to the invention aim at increasing the concentration of a substance (which can be water or another substance) in the gas phase within a gas flow (which can be air or another gas).
  • a substance which can be water or another substance
  • a gas flow which can be air or another gas.
  • most of the following description takes water and air as an example but can be easily transposed to other substances to evaporate and other gases.
  • thermodynamic processes use the water vapor contained in moist air for heating and cooling purposes.
  • the concentration of water also known as absolute humidity, plays an important role in the process efficiency. Indeed, a higher concentration directly increases the potential energy of the moist air because water specific enthalpy is higher in gaseous phase (vapor) than in liquid or solid phase.
  • the phase change enthalpy of water vapor to liquid/solid can thus be used for heat generation at a relatively low temperature (less than 100°C), for instance through condensation, sorption, or deposition.
  • Conventional air humidifiers are made of a wetted material through which a flow of air is circulated. Evaporation of the water into said air flow leads to lowering the temperature thereof down to the dew point, which may thereby stop the humidification process.
  • an object of the present invention is an apparatus according to claim 1 and a method according to claim 10.
  • the invention provides the crucial advantage of combining the humidification process and the heat compensation at a same location, namely on wetted surfaces of the heat exchange structure delimiting said portions of the gas flow passage.
  • the gas can thus accept more evaporated liquid per unit of dry gas before reaching the condensation limit, which increases the maximum possible humidification rate.
  • the invention makes it possible to optimize as much as possible the homogeneity of liquid distribution into the gas, and consequently, the homogeneity of heat exchange and liquid evaporation taking place in the heat exchanger.
  • top-to-bottom orientation of the gas and liquid flows within the gas passage enables the poured liquid to flow by gravity on the surfaces of the heat exchange structure delimiting said portions of the gas flow passage, starting from the top end of said heat exchange structure.
  • FIG. 1 An apparatus 10 for humidifying a gas according to a first embodiment of the invention is illustrated on figure 1 .
  • the apparatus 10 generally comprises a vessel 12 having a shape exhibiting symmetry of revolution about a longitudinal axis 14 and having two opposite open ends with respect to the longitudinal axis, namely a top end 16 and a bottom end 18.
  • the vessel 12 defines a gas flow passage 20 extending preferentially straight along a top-to-bottom direction D parallel to the longitudinal axis 14, from a gas inlet 22 defined through said top end 16 to a gas outlet 24 defined through said bottom end 18. It will therefore be understood that the gas inlet 22 extends transversally to the top-to-bottom direction D at a top end of the gas flow passage 20 so as to open downwards.
  • the words "top” and "bottom” are to be interpreted with respect to a nominal orientation of the apparatus 10 in use, as will become clearer in the following.
  • the gas inlet 22 preferentially extends over the whole transversal cross-section of the top end 16 of the vessel 12 with respect to the top-to-bottom direction D.
  • the gas outlet 24 preferentially extends transversally to the top-to-bottom direction D at the bottom end of the gas flow passage.
  • the apparatus 10 further comprises a heat exchanger 30 and a heat source 32.
  • the heat exchanger 30 comprises a heat exchange structure 34 arranged within the gas flow passage 20 between the gas inlet 22 and gas outlet 24.
  • the heat exchange structure 34 delimits portions 36 of the gas flow passage 20.
  • the heat exchange structure 34 comprises a plurality of fins 38 extending parallel to the top-to-bottom direction D.
  • the heat exchanger 30 comprises a heat transfer fluid circuit 40 configured for transferring heat to the heat exchange structure 34.
  • the heat transfer fluid circuit 40 comprises a duct or a plurality of interconnected ducts extending through the fins 38 transversally to the top-to-bottom direction D.
  • the heat transfer fluid circuit 40 may comprise one or more microchannel elements, for example microchannel plates, arranged in contact to the heat exchange structure 34.
  • the heat source 32 is a source of heat transfer fluid connected to an inlet 42 of the heat transfer fluid circuit 40.
  • a return channel 44 advantageously connects an outlet 46 of the heat transfer fluid circuit 40 to a return port of the heat source 32 so as to define a closed circuit for the heat transfer fluid.
  • the apparatus 10 further comprises a liquid pouring device 50 arranged within the gas flow passage 20 between the gas inlet 22 and the heat exchange structure 34 for pouring a liquid 51 downwards onto an upper end 52 of the heat exchange structure.
  • the heat exchange structure 34 is configured for such poured liquid to flow by gravity onto surfaces 53 of the heat exchange structure 34 which delimit said portions 36 of the gas flow passage 20.
  • the heat exchange structure 34 enables such poured liquid to wet the heat exchange structure 34 where the latter delimits said portions 36 of the gas flow passage.
  • the liquid pouring device 50 for example comprises a spray nozzle configured for evenly spraying the liquid downwards onto the upper end 52 of the heat exchange structure.
  • a spray nozzle configured for evenly spraying the liquid downwards onto the upper end 52 of the heat exchange structure.
  • the liquid pouring device 50 is configured for delivering liquid droplets of a diameter of at least 50 ⁇ m. Such droplets can for example be simply obtained by means of a spray nozzle supplied with water under a pressure of 4 to 6 bars.
  • the liquid pouring device 50 is configured for delivering one or multiple continuous flows of the liquid. By delivering large droplets or continuous flows of liquid, the liquid pouring device 50 helps limiting liquid pre-evaporation in the gas upstream from the heat exchanger 30. Devices configured for delivering larger droplets or continuous flows of liquid are also generally cheaper than devices able to deliver smaller droplets.
  • cross-section of vessel 12 may alternatively be of square shape, rectangular shape, or any other shape, provided the liquid pouring device 50 spray pattern be adapted to such shape.
  • the apparatus 10 further comprises a liquid inlet 54 connected to the liquid pouring device 50 for supplying the latter with said liquid.
  • the liquid inlet 54 is connected to a source of liquid 55.
  • the liquid is water.
  • the apparatus 10 also comprises a liquid collector 60 arranged within the gas flow passage 20 between the heat exchange structure 34 and the gas outlet 24.
  • the liquid collector 60 for example is a drain pan extending transversally to the top-to-bottom direction D.
  • the vessel 12 comprises an enlarged part 62 below the heat exchange structure 34 for delimiting a lower portion 64 of the gas flow passage 20 about the liquid collector 60, thus ensuring a sufficiently large free section about the liquid collector 60 to avoid obstructing the circulation of the gas down to the gas outlet 24.
  • a method for humidifying a gas by means of the apparatus 10 comprises steps of:
  • the method further comprises a step F of collecting possibly unevaporated liquid UL into the liquid collector 60 and evacuating said liquid through an output port of said liquid collector 60.
  • the heat exchange structure 34 is wetted on its full cross section at once. This allows the evaporation process to occur at the same pace in any given horizontal plane within the heat exchange structure 34.
  • the apparatus and method of the invention provide the additional advantages of low power consumption because the gas has only one heat exchanger to flow through and because of the straight geometry of the gas flow passage, which helps limiting the associated pressure drop.
  • Low power consumption also results from the fact that the liquid is simply poured or sprayed into large droplets or continuous flows onto the heat exchanger.
  • Such apparatus may also be of relative compacity.
  • conventional heat exchangers can be used, which helps limiting costs.
  • the apparatus can be operated at a low temperature and atmospheric pressure and thus proves to be secure. It can also be operated at pressures below or greater than atmospheric pressure.
  • FIGS 2 to 5 show various alternative embodiments of the apparatus 10 which all share the mode of operation and main technical advantages explained above with respect to the first embodiment.
  • Figure 2 illustrates a second embodiment of the apparatus 10, which is similar to the first embodiment but includes means for optimizing the flow rate of the liquid to be evaporated.
  • the exact amount or rate of liquid that the apparatus 10 can evaporate depends on a number of parameters, including dynamic ones. It is therefore difficult to analytically predict the optimum flowrate leading to the highest possible humidification. A too low flowrate would limit the humidification, while a too high flowrate would bring the risk of flooding the heat exchanger, leading to high pressure drop for the gas.
  • the apparatus 10 according to the second embodiment solves this problem by making it possible to constantly adjust the flowrate of poured liquid based on the pressure drop of the gas flow due to the heat exchange structure 34.
  • the apparatus 10 comprises a liquid flow controller 70 configured to adjust the flow rate of liquid supplied to the liquid pouring device 50 based on the drop of gas pressure within the gas flow passage 20 between a first location 72 upstream of the heat exchange structure 34 and a second location 74 downstream of the heat exchange structure 34.
  • This innovative feature is based on an indirect effect of surface tension forces that affect the liquid flow in a greater way than gravity or even gaseous flow in a given channel. Indeed, tension forces tend to aggregate the liquid on surfaces of the heat exchange structure 34, which reduces the available cross section for the gas within the portions 36 of the gas flow passage delimited by the heat exchange structure 34, thus increasing said gas pressure drop. Said gaseous pressure drop is therefore a relevant physical indication of the wetting level of the heat exchange structure 34.
  • the liquid flow controller 70 is for example configured for stopping or reducing liquid supply to the liquid pouring device 50 when said gas pressure drop becomes higher than a threshold, and for starting or increasing liquid supply to the liquid pouring device 50 when said gas pressure drop becomes lower than said threshold minus a hysteresis value.
  • the liquid flow controller 70 can be configured to implement more complex flow control algorithms.
  • the liquid flow controller 70 generally comprises a gas pressure drop sensor 76, an actuator for modulating the liquid flow supplied to the liquid pouring device 50, for instance by switching a pump or a valve on and off, and a control unit 80.
  • the gas pressure drop sensor 76 may be a differential pressure drop sensor pneumatically connected to the gas flow passage 20 on both sides of the heat exchange structure 34.
  • the control unit 80 is configured for running a flow control algorithm to output orders to the actuator that controls the liquid flow rate based on the output of said sensor read by the control unit 80.
  • Figure 2 shows two possible types of actuators.
  • the first type is a switching valve or control valve 82 connected to the source of liquid 55 in which case the latter must provide the liquid under pressure.
  • the second type is a pump 84 connected to a liquid tank 86 which then constitutes said source of liquid 55. In this case, the latter must be filled periodically either manually or automatically. Means for automatically filling such liquid tank 86 will be described below.
  • step C of the above method includes a sub-step C1 of having the flow controller 70 adjust the flow rate of liquid supplied to the liquid pouring device 50 based on the gas pressure drop within the gas flow passage 20 between a first location 72 upstream of the heat exchange structure 34 and a second location 74 downstream of the heat exchange structure 34.
  • Figure 3 illustrates a third embodiment of the apparatus 10, which is similar to the second embodiment but includes a recirculation circuit 90 connecting an output of the liquid collector 60 to the liquid pouring device 50. This enables to supply the liquid pouring device 50 with a possibly unevaporated part of the liquid, collected by the liquid collector 60.
  • the recirculation circuit 90 comprises:
  • the apparatus 10 shown in figure 3 further comprises means for automatically filling the liquid tank 86 with liquid from the source of liquid 55 when required.
  • means for example include a liquid level detector 100 provided inside the liquid tank 86 and a switching or control valve 102 provided on a connecting duct 104 which connects an output port of the source of liquid 55 to a second input port of the liquid tank 86.
  • the liquid tank 86 preferentially includes an overflow port connected to an evacuation drain 106.
  • the liquid tank 86 acts as a buffer between the source of liquid 55 and liquid collector 60 on the one hand and the liquid pouring device 50 on the other hand, while the means for automatically filling the liquid tank 86 ensure that there is always at least a minimum amount of liquid to be evaporated in the apparatus.
  • step F of the above method includes a sub-step F1 of returning an unevaporated part of the liquid collected by the liquid collector 60 to the liquid pouring device 50.
  • FIG. 4 illustrates an apparatus 10 according to a fourth embodiment of the invention, which is similar to the first embodiment but in which the heat transfer fluid circuit 40 and the source of hot heat transfer fluid are replaced by an electrical heater 110 configured for heating the heat exchange structure 34, and therefore connected to a source of electrical energy 112.
  • the electrical heater 110 thus constitutes the aforementioned heat source 32.
  • the electrical heater 110 and the heat exchange structure 34 may of course be combined into a single element.
  • step A of the above method includes heating the heat exchange structure 34 by the electrical heater 110.
  • FIG. 5 illustrates an apparatus 10 according to a fifth embodiment of the invention, which is similar to the first embodiment but which includes a heat pump 120 including said heat exchanger 30 as a condenser and including an evaporator 122 arranged outside of the vessel 12.
  • the evaporator can be heated by ambient air or any other external heat source and therefore constitutes the aforementioned source of hot heat transfer fluid or heat source 32.
  • Such heat pump 120 further includes a compressor 124 connecting an output of a heat transfer fluid circuit 125 of the evaporator 122 to an input of the heat transfer fluid circuit 40 of the heat exchanger 30 or condenser, and an expansion valve 126 connecting an output of the heat transfer fluid circuit 40 of the heat exchanger 30 or condenser to an input of the heat transfer fluid circuit 125 of the evaporator 122.
  • Such embodiment is characterized by a low electrical consumption, in particular if compared to the embodiment of figure 4 .

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
EP22306853.7A 2022-12-12 2022-12-12 Appareil et procédé d'humidification de gaz Pending EP4386272A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP22306853.7A EP4386272A1 (fr) 2022-12-12 2022-12-12 Appareil et procédé d'humidification de gaz

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP22306853.7A EP4386272A1 (fr) 2022-12-12 2022-12-12 Appareil et procédé d'humidification de gaz

Publications (1)

Publication Number Publication Date
EP4386272A1 true EP4386272A1 (fr) 2024-06-19

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ID=84602368

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22306853.7A Pending EP4386272A1 (fr) 2022-12-12 2022-12-12 Appareil et procédé d'humidification de gaz

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EP (1) EP4386272A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1012988A (fr) * 1950-02-17 1952-07-21 Condenseur à pulvérisation et ventilation
GB1582891A (en) * 1977-05-05 1981-01-14 Humidifier Group Ltd Humidifier
US4404814A (en) * 1981-10-30 1983-09-20 Beasley Albert W Auxiliary condenser cooling tool for refrigerated air conditioners
DE102008031586B3 (de) * 2008-07-03 2009-07-02 Terrawater Gmbh Befeuchtungswärmetauscher
US20210325059A1 (en) * 2019-08-05 2021-10-21 Taikisha Ltd. Air Conditioner for Paint Booth

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1012988A (fr) * 1950-02-17 1952-07-21 Condenseur à pulvérisation et ventilation
GB1582891A (en) * 1977-05-05 1981-01-14 Humidifier Group Ltd Humidifier
US4404814A (en) * 1981-10-30 1983-09-20 Beasley Albert W Auxiliary condenser cooling tool for refrigerated air conditioners
DE102008031586B3 (de) * 2008-07-03 2009-07-02 Terrawater Gmbh Befeuchtungswärmetauscher
US20210325059A1 (en) * 2019-08-05 2021-10-21 Taikisha Ltd. Air Conditioner for Paint Booth

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