Three-fluid heat exchanger and humidity control device

Abstract

In this three-fluid heat exchanger, a plurality of heat exchange units are stacked in the vertical direction, each of the heat exchange units having: a tubular heat transfer tube inside which a heat medium fluid is made to flow and in which minute irregularities are formed on the outer peripheral surface from one end to the other end in a cross-section viewed along the axial direction; a spray tray in which a slit having an edge extending along the axial direction of the heat transfer tube is formed in a bottom plate, a radially outer upper part of the heat transfer tube is positioned in contact with the edge from one end to the other end, and a hygroscopic liquid is supplied so as to flow down from the slit to the outer periphery of the heat transfer tube; and a filler that brings the hygroscopic liquid and a gas to be treated into contact with each other below the spray tray.

Description

Three-fluid heat exchanger and humidity control device

[0001] The present disclosure relates to a three-fluid heat exchanger and a humidity control device.

[0002] Conventionally, a heat exchanger that performs heat exchange between a heat transfer medium fluid and a target liquid by dripping the target fluid outside a heat transfer tube through which the heat transfer medium fluid flows inside and flowing it over the surface of the heat transfer tube has been adopted in refrigerators, air conditioners, etc.

[0003] For example, Japanese Patent No. 6545742 proposes a heat exchanger used in a wet type humidity control device, in which a heat transfer tube and a filler are repeatedly arranged in the vertical direction, and air and a hygroscopic liquid are brought into contact there. This heat exchanger is a three-fluid heat exchanger in which three fluids, a heat transfer medium fluid, a hygroscopic liquid, and air, perform heat exchange.

[0004] In this three-fluid heat exchanger, the hygroscopic liquid, which is the target liquid, flows over the outer surface of the heat transfer tube and exchanges heat with the heat source fluid flowing inside the heat transfer tube, so that the hygroscopic liquid is cooled or heated. It makes sufficient gas-liquid contact with air in the filler below, and is cooled or heated again by flowing over the outer surface of the heat transfer tube in the lower part, and by repeating this, the moisture absorption capacity and moisture release capacity are restored, and more efficient moisture transfer can be achieved.

[0005] In such a heat transfer tube, it is advantageous in terms of heat exchange efficiency that the target liquid spreads sufficiently over the outer surface of the heat transfer tube. If there is a portion on the outer surface of the heat transfer tube where the target liquid does not flow, the heat exchange rate between the heat transfer medium fluid and the hygroscopic liquid, which is the target liquid, will be lowered by that amount.

[0006] As a measure for widening the wetted area of the outer surface of the heat transfer tube, in the wet type humidity control device of Japanese Patent No. 6545742, a tray for evenly supplying the target liquid to the heat transfer tube is provided above the heat transfer tube. A plurality of holes are formed in the bottom surface of the tray along the axial direction of the heat transfer tube, and the hygroscopic liquid received in the tray is discharged downward through the holes.

[0007] However, when the hygroscopic liquid is discharged downwards through holes in the bottom of the tray, there are areas in the axial direction of the heat transfer tube where holes are formed and areas where they are not, so there is room to improve the uniformity of the hygroscopic liquid flowing along the outer surface of the heat transfer tube in the axial direction.

[0008] This disclosure is made in consideration of the above facts and aims to improve the uniformity of the hygroscopic liquid flowing over the outer surface of the heat transfer tube.

[0009] A three-fluid heat exchanger according to a first aspect of the present disclosure comprises a heat transfer tube through which a heat transfer fluid flows, with minute irregularities formed on its outer surface when viewed in cross-section along the axial direction, spanning from one end to the other; a spray tray formed in the bottom plate with a slit extending along the axial direction of the heat transfer tube, the radially outer upper part of the heat transfer tube positioned while in contact with the slit from one end to the other, and a hygroscopic liquid supplied flowing down from the slit to the outer circumference of the heat transfer tube; and a gas-liquid contact section below the spray tray that brings the hygroscopic liquid into contact with the gas to be treated. A plurality of heat exchange units are stacked vertically.

[0010] In the first embodiment of the three-fluid heat exchanger, a slit is formed in the spray tray, with its edge extending along the axial direction of the heat transfer tube. The radially outer upper part of the heat transfer tube is placed across the slit from one end to the other and in contact with the edge, thereby positioning the heat transfer tube relative to the slit. Consequently, the hygroscopic liquid flows down the outer circumference of the heat transfer tube at a position continuous with the axial direction of the heat transfer tube where it is in contact with the edge of the slit. This improves the uniformity of the hygroscopic liquid flowing on the outer surface of the heat transfer tube, thereby improving the heat exchange rate between the heat transfer fluid and the hygroscopic liquid.

[0011] A three-fluid heat exchanger according to a second aspect of the present disclosure is configured such that the heat transfer tubes of one of the heat exchange units are positioned between the bottom plate of the spray tray and the gas-liquid contact portion of another heat exchange unit adjacent to it vertically below.

[0012] In the third embodiment of the three-fluid heat exchanger, multiple heat exchange units can be stacked by arranging the heat transfer tubes between the bottom plate of the spray tray and the gas-liquid contact portion of other heat exchange units adjacent to each other vertically below.

[0013] A three-fluid heat exchanger according to a third aspect of the present disclosure is provided, wherein an elastic member is positioned between the spray tray and the gas-liquid contact portion to press the gas-liquid contact portion toward the heat transfer tube.

[0014] In the third embodiment of the three-fluid heat exchanger, the gas-liquid contact area can be stably brought into contact with the heat transfer tubes by pressing the gas-liquid contact area toward the heat transfer tubes with an elastic member.

[0015] In a third aspect of the present disclosure, the three-fluid heat exchanger has a plurality of slits formed in parallel on the bottom plate of the spray tray, and a plurality of through holes formed between the slits so as to be parallel to the slits.

[0016] In the third embodiment of the three-fluid heat exchanger, multiple through-holes are formed in the bottom plate of the spray tray in addition to the slits. Therefore, even if the slits become blocked with debris, the hygroscopic liquid can be discharged through the through-holes, preventing excessive accumulation and overflow of the hygroscopic liquid in the spray tray.

[0017] A third fluid heat exchanger according to a fifth aspect of the present disclosure further comprises an outer periphery weir formed along the outer circumference of the through hole and having a height lower than the side plate formed on the outer circumference of the spray tray.

[0018] In the third embodiment of the three-fluid heat exchanger, an outer periphery weir is formed along the outer circumference of the through-hole, so that the hygroscopic liquid retained in the spray tray does not enter the through-hole up to the height of the outer periphery weir. Therefore, when the hygroscopic liquid flows smoothly from the slit to the heat transfer tube, it is possible to prevent the hygroscopic liquid from flowing down from the through-hole.

[0019] In a third-fluid heat exchanger according to a sixth aspect of the present disclosure, a plurality of slits are formed in parallel on the bottom plate of the spray tray, and sub-slits are formed between the slits so as to be parallel to the slits.

[0020] In the third embodiment of the three-fluid heat exchanger, a sub-slit is formed in the bottom plate of the spray tray in addition to the slit. Therefore, even if the slit becomes blocked with debris, the hygroscopic liquid can be discharged through the sub-slit, preventing excessive accumulation and overflow of the hygroscopic liquid in the spray tray.

[0021] A three-fluid heat exchanger according to a seventh aspect of the present disclosure further comprises a pair of weirs formed along both inner edges of the sub-slits and having a height lower than the side plates formed on the outer circumference of the spray tray.

[0022] In the seventh embodiment of the three-fluid heat exchanger, a pair of weirs are formed along both inner edges of the sub-slits, so that the hygroscopic liquid remaining in the spray tray does not enter the sub-slits up to the height of the pair of weirs. Therefore, when the hygroscopic liquid flows smoothly from the slits to the heat transfer tubes, it is possible to prevent the hygroscopic liquid from flowing down from the sub-slits.

[0023] A humidity control device according to the eighth aspect of this disclosure comprises a three-fluid heat exchanger as described in any one of the first to fifth aspects.

[0024] According to the humidity control device of the eighth embodiment, the uniformity of the hygroscopic liquid flowing on the outer surface of the heat transfer tube can be improved, and the heat exchange rate between the heat transfer fluid and the hygroscopic liquid can be improved.

[0025] The technology of this disclosure makes it possible to improve the uniformity of the hygroscopic liquid flowing on the outer surface of the heat transfer tube.

[0026] This is a schematic diagram showing the configuration of the humidity control device of this embodiment. This is a schematic diagram of a processing machine equipped with a three-fluid heat exchanger of this embodiment. This is an exploded perspective view of the heat exchange unit constituting the three-fluid heat exchanger of this embodiment. This is a perspective view of the heat exchange unit constituting the three-fluid heat exchanger of this embodiment. This is a partial cross-sectional view of the heat exchange unit constituting the three-fluid heat exchanger of this embodiment. This is a perspective view of the packing material of this embodiment. This is a partial side view of the heat transfer tube of this embodiment. This is a modified side view of the heat transfer tube of this embodiment. This is another modified side view of the heat transfer tube of this embodiment. This is another modified side view of the heat transfer tube of this embodiment. This is a perspective view of a spray tray of a modified embodiment. This is a perspective view of a spray tray of another modified embodiment. This is a perspective view of the outer perimeter weir on the spray tray of another modified embodiment. This is a cross-sectional view of the vicinity of the outer perimeter weir on the spray tray of another modified embodiment. This is a perspective view of a pair of weirs on the spray tray of another modified embodiment. This is a cross-sectional view of the vicinity of a pair of weirs on the spray tray of another modified embodiment.

[0027] The three-fluid heat exchanger and humidity control device related to this disclosure will be described below with reference to the drawings.

[0028] The humidity control device 100 according to this disclosure, as shown in Figure 1, includes a processing machine 10 that takes in air to be treated and brings it into contact with a hygroscopic liquid to dehumidify the air to be treated, and a regenerator 30 that regenerates the hygroscopic liquid used in the dehumidification process by the processing machine 10. Here, regeneration of the hygroscopic liquid means increasing the concentration of the hygroscopic liquid, which has been diluted by absorbing moisture from the air to be treated through dehumidification, and restoring the dehumidification capacity of the hygroscopic liquid.

[0029] The processing unit 10 discharges the dehumidified air into the space to be dehumidified, and the regenerator 30 discharges the air used for regeneration outside the space to be dehumidified.

[0030] As an example of a hygroscopic liquid, an aqueous solution of lithium chloride (LiCl) can be used. The hygroscopic liquid can be any liquid with a saturated vapor pressure lower than that of water at the same temperature, and is not limited to aqueous solutions of lithium chloride; it may also be lithium bromide, calcium chloride, magnesium chloride, aqueous solutions of salts, ionic liquids, highly hygroscopic polyhydric alcohols, or other hygroscopic liquids.

[0031] The processing machine 10 and the regenerator 30 are connected by a first hygroscopic liquid pipeline 51 and a second hygroscopic liquid pipeline 52. The first hygroscopic liquid pipeline 51 is a pipeline for sending hygroscopic liquid from the processing machine 10 to the regenerator 30, and the second hygroscopic liquid pipeline 52 is a pipeline for sending hygroscopic liquid from the regenerator 30 to the processing machine 10. A pump 53 is provided in the first hygroscopic liquid pipeline 51 and a pump 54 is provided in the second hygroscopic liquid pipeline 52. By circulating the hygroscopic liquid between the processing machine 10 and the regenerator 30 using the first hygroscopic liquid pipeline 51 and the second hygroscopic liquid pipeline 52, the hygroscopic liquid used in the processing machine 10 can be regenerated in the regenerator 30, and the hygroscopic liquid regenerated in the regenerator 30 can be returned to the processing machine 10.

[0032] Figure 2 is a view of the processing machine 10 in a cross-section perpendicular to the longitudinal direction of the heat transfer tube 16. The configuration of the processing machine 10 will be explained below in conjunction with Figures 1 and 2. The processing machine 10 is equipped with a housing 11 having an air intake port 12 and an exhaust port 13. The exhaust port 13 has an exhaust fan 14 that forcibly exhausts the air inside the housing 11 and also takes in air to be processed, such as return air from the space to be dehumidified or outside air, through the air intake port 12. The exhaust port 13 is connected to the space to be dehumidified through a duct or the like, and the dehumidified air is discharged from the exhaust port 13 to the space to be dehumidified.

[0033] The housing 11 contains a distributor 15, heat transfer tubes 16, a spray tray 70, packing material 17, a bottom packing material 18, a solution tank 19, and left and right side plates 26. The gas-liquid contact area refers to the part where gas and liquid come into contact. The liquid can be in the form of a liquid film or droplets, and the gas-liquid contact area includes the surface of the heat transfer tubes 16 where a liquid film is formed and the liquid film is in contact with the gas. The packing material 17 that constitutes the gas-liquid contact area is provided to increase the contact area between the liquid and gas (gas-liquid contact area). It is not essential if a sufficient gas-liquid contact area can be secured without packing material, such as when the density of heat transfer tubes 16 is high.

[0034] The side plates 26 constitute the left and right outer walls of the three-fluid heat exchanger 20, and are constructed by arranging a pair of plate materials so that they face each other in the vertical direction.

[0035] The distributor 15 is a roughly tray-shaped component positioned above the three-fluid heat exchanger 20, and has multiple distribution ports formed on its lower surface for dripping a hygroscopic liquid downwards. The distribution ports are formed between the left and right side plates 26, along the lower heat transfer tubes 16 of the distributor 15.

[0036] The distributor 15 drops the hygroscopic liquid from its distribution port to supply the hygroscopic liquid to the upper part of the three-fluid heat exchanger 20 (specifically, the spray tray 70, which will be described later). The hygroscopic liquid supplied to the three-fluid heat exchanger 20 flows sequentially from the top to the bottom through the three-fluid heat exchanger 20 by gravity and surface tension, passing through the bottom packing material 18 of the final stage and falling into the solution tank 19. Here, gravity flow means that the hygroscopic liquid flows due to gravity, surface tension, etc., and does not require a power source such as a pump to move the hygroscopic liquid. The solution tank 19 receives and temporarily holds the hygroscopic liquid that has fallen through the three-fluid heat exchanger 20 and the bottom packing material 18.

[0037] The arrows in Figure 2 indicate the airflow. The air to be processed, taken into the housing 11 from the intake port 12, flows horizontally through the housing 11 by the drive of the exhaust fan 14 and is discharged from the exhaust port 13 into the space to be dehumidified.

[0038] In this manner, three fluids—a hygroscopic liquid, a heat transfer fluid, and the air to be treated—flow into the three-fluid heat exchanger 20, and heat exchange takes place between these three fluids. Specifically, the hygroscopic liquid is cooled by the refrigerant via the heat transfer tubes 16, and the air to be treated is cooled by direct contact with the hygroscopic liquid. Furthermore, the temperature of the hygroscopic liquid rises due to contact with the air to be treated, which is at a higher temperature than the hygroscopic liquid, and also due to the heat of absorption (heat of condensation of water vapor and heat of dilution of the solution) from the absorption of water vapor in the air to be treated. Thus, the three-fluid heat exchanger 20 has a configuration that brings the hygroscopic liquid, the heat transfer fluid, and the air to be treated into direct or indirect contact, and the three-fluid heat exchanger 20 facilitates the transfer of heat and matter (water), that is, heat exchange of both sensible and latent heat.

[0039] The regeneration unit 30 has the same configuration as the processing unit 10. In the three-fluid heat exchanger 40, three fluids—a hygroscopic liquid, a heat transfer medium (heat transfer fluid), and regeneration air—flow in, and heat exchange takes place between these three fluids. The hygroscopic liquid is heated by the heat transfer medium via the heat transfer tubes 16, and the regeneration air is heated by direct contact with the hygroscopic liquid. In addition, the temperature of the hygroscopic liquid decreases by contact with the regeneration air, which is at a lower temperature than the hygroscopic liquid, and also by negative heat absorption due to the release of moisture into the regeneration air. In this way, in the three-fluid heat exchanger 40, the hygroscopic liquid, the heat transfer medium (heat transfer fluid), and the regeneration air come into direct or indirect contact, and the transfer of heat and matter (water), that is, heat exchange of both sensible and latent heat, takes place.

[0040] The humidity control device 100 includes a heat pump 60 for supplying refrigerant to the heat transfer tubes 16 of the three-fluid heat exchanger 20 and supplying a heat transfer medium to the heat transfer tubes 16 of the three-fluid heat exchanger 40. Each heat transfer tube 16 constitutes a heat exchanger of the heat pump 60. That is, the heat pump 60 consists of the heat transfer tubes 16 of the three-fluid heat exchanger 20 which function as an evaporator, a compressor 61, the heat transfer tubes 16 of the three-fluid heat exchanger 40 which function as a condenser, an expansion valve 62, and a heat transfer medium fluid tube 63 that connects these in this order. The heat pump 60 can also be configured to have the heat transfer tubes 16 of the three-fluid heat exchanger 20 function as a condenser and the heat transfer tubes 16 of the three-fluid heat exchanger 40 function as condensers by swapping the arrangement of the compressor 61 and the expansion valve 62.

[0041] Since the three-fluid heat exchanger 20 and the three-fluid heat exchanger 40 have the same configuration, the configuration of the three-fluid heat exchanger 20 will be described below as an example. In the three-fluid heat exchanger 20, multiple sets (stages) of heat exchange units 22, each having a packing material 17, a spreading tray 70, and heat transfer tubes 16, are arranged in the vertical direction.

[0042] As shown in FIG. 3, the spraying tray 70 has side plates 71 and a bottom plate 72. The bottom plate 72 is in the shape of a rectangular plate and is horizontally arranged so as to span between the side plates 26. The side plates 71 are provided so as to rise from each of the four sides of the bottom plate 72. When the side plate 71 arranged in the direction along the side plate 26 is defined as the side plate 71A, and the side plate 71 arranged in the direction orthogonal to the side plate 71A is defined as the side plate 71B, the side plate 71A is raised to a position higher than the side plate 71B.

[0043] A plurality of slits 74 are formed in the bottom plate 72 from one side to the other side of the side plate 26. The slits 74 extend along the axial direction of the heat transfer tube 16 described later. The plurality of slits 74 (six in the present embodiment) are arranged in parallel at equal intervals. The portion constituting the outer edge of the slit 74 is referred to as a slit edge 74A. The slit 74 is also formed to extend in the side plate 71A.

[0044] As shown in FIG. 5, a diffusion member 76 is laid on the upper surface of the bottom plate 72. As the diffusion member 76, a non-woven fabric can be used. A slit 76A is formed in a portion of the diffusion member 76 corresponding to the slit 74. The diffusion member 76 diffuses the hygroscopic liquid in the surface direction (the bottom surface direction of the spraying tray 70) by capillary action. In each spraying tray 70, the hygroscopic liquid diffuses in the surface direction while penetrating the diffusion member 76, and flows down and is supplied to the heat transfer tube 16 below from the slit 74.

[0045] A gas-liquid contact space R is formed between the spraying tray 70 and the heat transfer tube 16. A plurality of elastic members 78 are provided at a plurality of positions along the side plate 71B on the spraying tray 70, and a filler 17 is arranged in the gas-liquid contact space R on the elastic members 78. The filler 17 is pressed toward the heat transfer tube 16 by the elastic members 78. The filler 17 is in the shape of a rectangular parallelepiped that covers the bottom plate 72 as a whole. FIG. 6 shows a perspective view of the filler 17. The filler 17 is formed by alternately laminating a first plate 17A and a second plate 17B processed into a corrugated concavo-convex shape in the axial direction of the heat transfer tube 16 in order to increase the surface area per unit volume. The direction in which the concavity or convexity of the corrugated concavo-convexity extends is referred to as the extending direction of the corrugated wall.

[0046] The first plate 17A has a first angle θ1 in which the extending angle of the corrugated wall is obliquely downward from the upstream side to the downstream side of the air to be treated with respect to the horizontal direction S1, and the second plate 17B has a second angle θ2 in which the extending angle of the corrugated wall is obliquely upward from the upstream side to the downstream side of the air to be treated with respect to the horizontal direction S1. This is a structure that adjusts the flow direction of the liquid, promotes the rectification of the passing gas, and the contact between the liquid and the gas.

[0047] The packing material 17 can be formed by adhering sheets (plates) such as glass fibers and ceramic fibers in addition to the hydrophilic cellulose-based material, or by integrating cellulose, glass fibers, ceramic fibers, etc. with a binder or the like.

[0048] When the packing material 17 is not arranged in the gas-liquid contact space R, the hygroscopic liquid present in the gas-liquid contact space R contacts the gas while falling vertically as a liquid film or liquid droplets, and the gas-liquid contact space R functions as a gas-liquid contact portion.

[0049] The heat transfer tube 16 has the end of the straight portion extending in the left-right direction (horizontal direction) held by the side plate 26, and is connected outside the side plate 26 to the heat transfer tubes 16 adjacent in the up-down direction. The heat transfer tubes 16 overlapping in the up-down direction are configured as a single tube that meanders without branching as a whole. A plurality of rows of the single heat transfer tube 16 are arranged. In this embodiment, an example is given in which there are 6 heat transfer tubes 16 and the heat transfer fluid is branched into 6 branches, but the number of branches is set according to the flow rate of the heat transfer fluid. A heat transfer fluid as a refrigerant flows inside the heat transfer tube 16. The heat transfer tube 16 is preferably made of metal from the viewpoint of strength, and particularly preferably a material having corrosion resistance against the hygroscopic liquid.

[0050] The outer surface (circumferential surface) of the heat transfer tube 16 is processed to create fine irregularities 16A so as to form a gap between the slit 74 and the heat transfer tube 16, to increase the surface area, and to promote heat exchange between the fluid outside the tube (hygroscopic liquid), the fluid inside the tube (heat transfer fluid), and the gas to be processed. As shown in Figure 7A, the fine irregularities 16A appear as bumps and dips when the heat transfer tube 16 is viewed in cross-section along the axial direction S, and are formed spanning from one end to the other along the axial direction S. The protrusion height or depth H of the fine irregularities 16A from the outer surface of the heat transfer tube 16 is approximately 1.0 mm to 1.8 mm, and the pitch P of the irregularities is approximately 0.7 mm to 1.3 mm. The width W of the axial direction S depends on the pitch P of the irregularities and the shape of the irregularities. The fine irregularities can consist of spiral grooves 16A (see Figure 7A), spiral fins 16B (see Figure 7B), annular fins 16C (see Figure 7C), and protrusions 16D (see Figure 7D).

[0051] The heat transfer tube 16 of one heat exchange unit 22 is positioned between the bottom plate 72 of a spray tray 70 located above it and the packing material 17 of another adjacent heat exchange unit 22 located vertically below it. The radially outer upper part of the heat transfer tube 16 is in contact with the slit edge 74A of a slit 74 formed in the bottom plate 72 from one end to the other between the side plates 26, thereby positioning the slit 74 and the heat transfer tube 16. The heat transfer tube 16 is in close contact with the packing material 17 by the elastic force of an elastic member 78 on the bottom plate 72 of the spray tray 70 located below it. The width W of the slit 74 is set such that the positioned heat transfer tube 16 does not protrude from the upper surface of the bottom plate 72, and is set according to the thickness of the bottom plate 72 and the outer diameter of the heat transfer tube 16. The outer diameter of the heat transfer tube 16 is smaller than the distance (spacing) between the bottom plate 72 of the spray tray 70 and the packing material 17.

[0052] (Effects) In the humidity control device 100 described above, the operation of the heat pump 60 causes refrigerant to flow into the heat transfer tubes 16 of the three-fluid heat exchanger 20 and heat transfer medium to flow into the heat transfer tubes 16 of the three-fluid heat exchanger 40. The operation of the pump 54 supplies hygroscopic liquid to the distributor 15 of the three-fluid heat exchanger 20, and the operation of the pump 53 supplies hygroscopic liquid to the distributor 15 of the three-fluid heat exchanger 40. In addition, the operation of the fan 14 causes the air to be treated in the three-fluid heat exchanger 20 to be taken in from the intake port 12 and discharged from the exhaust port 13, and in the three-fluid heat exchanger 40, regeneration air is taken in from the intake port 12 and discharged from the exhaust port 13.

[0053] The hygroscopic liquid supplied to the distributor 15 of the three-fluid heat exchanger 20 is supplied from the distribution port onto the uppermost spray tray 70. The hygroscopic liquid supplied onto the spray tray 70 is diffused by the diffusion member 76 on the spray tray 70, flows down the outer surface of the heat transfer tubes 16 through the slits 74, and is cooled by the refrigerant flowing through the heat transfer tubes 16. Then, it is supplied to the next spray tray 70 via the packing material 17. The air to be treated flows through the packing material 17 in a direction intersecting with the hygroscopic liquid, and the two come into gas-liquid contact, causing the hygroscopic liquid to absorb moisture from the air to be treated.

[0054] The above-mentioned flow, cooling, and moisture absorption of the hygroscopic liquid are repeated below, and the air to be treated is dehumidified and supplied to the target space. The hygroscopic liquid that falls after passing through the lowest packing material 18 is received in the solution tank 19 and temporarily stored, and then supplied by the pump 53 to the distributor 15 of the three-fluid heat exchanger 40 via the heat exchanger 55.

[0055] The hygroscopic liquid supplied to the distributor 15 of the three-fluid heat exchanger 40 is supplied from the distribution port onto the uppermost spray tray 70. The hygroscopic liquid supplied onto the spray tray 70 is diffused by the diffusion member 76 on the spray tray 70, flows down the outer surface of the heat transfer tubes 16 through the slits 74, and is heated by the heat transfer medium flowing through the heat transfer tubes 16. Then, it is supplied to the next spray tray 70 via the packing material 17. Regeneration air flows through the packing material 17 in a direction intersecting with the hygroscopic liquid, and as the two come into gas-liquid contact, moisture is released from the hygroscopic liquid into the regeneration air.

[0056] The above processes of flowing, heating, and moisture release of the hygroscopic liquid are repeated at the bottom, regenerating the hygroscopic liquid. The hygroscopic liquid that falls after passing through the bottom packing material 18 is received in the solution tank 19 for temporary storage and then supplied by the pump 54 to the distributor 15 of the three-fluid heat exchanger 20 via the heat exchanger 55.

[0057] In the three-fluid heat exchangers 20 and 40 of this embodiment, a slit 74 is formed in the spray tray 70, with its edge extending along the axial direction of the heat transfer tube 16. The radially outer upper part of the heat transfer tube 16 contacts the slit edge 74A of the slit 74 from one end to the other, thereby positioning the slit 74 and the heat transfer tube 16. Therefore, the hygroscopic liquid supplied onto the spray tray 70 flows down the outer circumference of the heat transfer tube 16 at a position continuous in the axial direction of the heat transfer tube 16 where it contacts the slit edge 74A of the slit 74. This improves the uniformity of the hygroscopic liquid flowing on the outer surface of the heat transfer tube 16 compared to when the hygroscopic liquid flows down from holes scattered in the axial direction, thereby improving the heat exchange rate between the heat transfer fluid and the hygroscopic liquid.

[0058] Furthermore, in the three-fluid heat exchangers 20 and 40 of this embodiment, the heat transfer tubes 16 are positioned between the bottom plate 72 of the spray tray 70 and the packing material 17 of other heat exchange units 22 located vertically below, thereby stacking multiple heat exchange units 22 and improving the heat exchange rate between the heat transfer fluid and the hygroscopic liquid. In addition, the elastic member 78 presses the packing material 17 toward the heat transfer tubes 16, thereby improving the adhesion between the heat transfer tubes 16 and the packing material 17. Moreover, by setting the thickness (height) dimension of the packing material 17 to be smaller than the height at which the packing material 17 adheres to the heat transfer tubes 16, and by using the thickness of the elastic member 78 to ensure close contact between the heat transfer tubes 16 and the packing material 17, the spray tray 70 can be easily removed.

[0059] Furthermore, since the filler material 17 is pressed toward the heat transfer tube 16 by the elastic member 78, the filler material 17 can be stably brought into contact with the heat transfer tube 16.

[0060] Furthermore, in the three-fluid heat exchangers 20 and 40 of this embodiment, the packing material 17 is formed by alternately stacking a first plate 17A and a second plate 17B, and the extension angles of the wave walls with respect to the horizontal direction S1 are angles θ1 and θ2, which are diagonally downward and upward from the upstream side to the downstream side as the air to be treated passes. By configuring the packing material 17 in this way, the hygroscopic liquid and the air to be treated can be efficiently brought into contact.

[0061] <Modification 1> The spray tray 70 can have through-holes 75A formed in it, as shown in Figure 8. The through-holes 75A are formed between adjacent slits 74 and parallel to the slits 74. Preferably, the through-holes 75A are formed in the middle portion between adjacent slits 74. The shape of the through-holes 75A can be a perfect circle, an ellipse, a polygon, or any other shape. The total opening area of ​​the through-holes 75A is adjusted so that even when the slits 74 are blocked, the liquid level of the hygroscopic liquid on the spray tray 70 is less than the height of the side plate 71. Specifically, an upper limit is determined for the liquid level of the hygroscopic liquid, and the total area of ​​the holes is determined based on various conditions such as the flow rate and viscosity of the hygroscopic liquid, and the resistance of the through-holes 75A, so that the liquid level of the hygroscopic liquid does not exceed the upper limit.

[0062] By forming the through-hole 75A, even if the slit 74 becomes blocked with debris, the hygroscopic liquid can flow out through the through-hole 75A, preventing excessive accumulation of the hygroscopic liquid in the spray tray 70 and preventing it from overflowing beyond the side plate 71. In addition, gas can pass through the through-hole 75. Therefore, the gas to be treated can enter and exit multiple spaces partitioned by the spray tray 70.

[0063] Due to surface tension, the hygroscopic liquid tends to move to the area where the slit edge 74A of the slit 74 is in contact with the heat transfer tube 16. Since there is nothing in contact below through the through hole 75A, the hygroscopic liquid will not flow down unless there is a certain liquid level. Therefore, in the spray tray 70, most of the hygroscopic liquid flows down from the slit 74 along the heat transfer tube 16, and when the slit 74 is blocked, it flows down through the through hole 75A.

[0064] Furthermore, as shown in Figure 9, the spray tray 70 can also have sub-slits 75B instead of through-holes 75A. The sub-slits 75B are formed between adjacent slits 74, parallel to the slits 74. It is preferable that the sub-slits 75B are formed in the intermediate portion between adjacent slits 74. The total opening area of ​​the sub-slits 75B is determined in the same manner as the through-holes 75A.

[0065] <Modification 2> As shown in Figure 10A, an outer peripheral weir 75AW may be provided on the outer circumference of the through hole 75A described in Modification 1. As shown in Figure 10B, the outer peripheral weir 75AW is set to a height H1 that is lower than the height H0 of the side plate 71B. Therefore, the flow of the hygroscopic liquid from the through hole 75A will only occur after the water level of the hygroscopic liquid in the spray tray 70 exceeds H1. Thus, when the hygroscopic liquid flows smoothly through the heat transfer tube 16 from the slit 74, the flow of the hygroscopic liquid from the through hole 75A can be prevented.

[0066] Furthermore, as shown in Figure 11A, a pair of weirs 75BW may be provided on both inner edges of the sub-slit 75B described in Modification 1. The pair of weirs 75BW are set at a height H2 that is lower than the height H0 of the side plate 71B, as shown in Figure 11B. Therefore, the flow of the hygroscopic liquid from the sub-slit 75B will only occur after the water level of the hygroscopic liquid in the spray tray 70 exceeds H2. Thus, when the hygroscopic liquid flows smoothly from the slit 74 through the heat transfer tube 16, the flow of the hygroscopic liquid from the sub-slit 75B can be prevented.

[0067] Furthermore, although the three-fluid heat exchangers 20 and 40 are applied to a humidity control device in this embodiment, they can also be applied to absorption refrigerators or drip-film heat exchangers that use a hygroscopic liquid as the fluid outside the pipes. When applied to an absorption refrigerator equipped with four chambers: a condenser, an evaporator, a regenerator, and an absorber, the three-fluid heat exchanger of the present invention can be applied to the absorber and the regenerator. The hygroscopic liquid of the present invention is a concept that includes absorbent liquids used in absorption refrigerators, and if the refrigerant is water, the gas to be treated in this case will be water vapor.

[0068] The following additional information is disclosed regarding the above embodiment.

[0069] (Note 1) A three-fluid heat exchanger having a plurality of heat exchange units stacked vertically, each having: a heat transfer tube through which a heat transfer fluid flows; a bottom plate with a slit formed therein, the edge of which extends along the axial direction of the heat transfer tube, and the radially outer upper part of the heat transfer tube positioned so as to be in contact with the edge from one end to the other, and a spray tray for supplying a hygroscopic liquid flowing down from the slit to the outer circumference of the heat transfer tube; and a gas-liquid contact section placed on the spray tray for bringing the hygroscopic liquid into contact with the air to be treated. (Note 2) The three-fluid heat exchanger according to Note 1, wherein the heat transfer tube of one of the heat exchange units is positioned between the bottom plate of the spray tray and the gas-liquid contact section of another heat exchange unit adjacent to it vertically below. (Note 3) The three-fluid heat exchanger according to Note 2, wherein an elastic member is positioned between the spray tray and the gas-liquid contact section to press the gas-liquid contact section toward the heat transfer tube. (Note 4) The three-fluid heat exchanger according to Note 1, wherein a plurality of slits are formed in parallel on the bottom plate of the spraying tray, and a plurality of through holes are formed between the slits so as to be parallel to the slits. (Note 5) The three-fluid heat exchanger according to Note 4, further comprising an outer peripheral weir formed along the outer circumference of the through holes and having a height lower than the side plate formed on the outer circumference of the spraying tray. (Note 6) The three-fluid heat exchanger according to Note 1, wherein a plurality of slits are formed in parallel on the bottom plate of the spraying tray, and sub-slits are formed between the slits so as to be parallel to the slits. (Note 7) The three-fluid heat exchanger according to Note 6, further comprising a pair of weirs formed along both inner edges of the sub-slits and having a height lower than the side plate formed on the outer circumference of the spraying tray. (Note 8) A humidity control device comprising the three-fluid heat exchanger according to any one of Notes 1 to 7.

Claims

1. A three-fluid heat exchanger comprising: a heat transfer tube through which a heat transfer fluid flows, with minute irregularities formed on its outer surface when viewed in cross-section along the axial direction, spanning from one end to the other; a spray tray with a slit formed in the bottom plate, the edge of which extends along the axial direction of the heat transfer tube, and the radially outer upper part of the heat transfer tube positioned while in contact with the edge spanning from one end to the other, and a hygroscopic liquid supplied flowing down from the slit to the outer circumference of the heat transfer tube; and a gas-liquid contact section below the spray tray, which brings the hygroscopic liquid into contact with the gas to be treated; and a plurality of these heat exchange units stacked vertically.

2. The three-fluid heat exchanger according to claim 1, wherein the heat transfer tube of one of the heat exchange units is positioned between the bottom plate of the spray tray and the gas-liquid contact portion of another heat exchange unit adjacent to it vertically below.

3. The three-fluid heat exchanger according to claim 2, wherein an elastic member is disposed between the spray tray and the gas-liquid contact portion to press the gas-liquid contact portion toward the heat transfer tube.

4. The three-fluid heat exchanger according to claim 1, wherein the bottom plate of the spray tray has a plurality of slits formed in parallel, and a plurality of through holes are formed between the slits so as to be parallel to the slits.

5. The three-fluid heat exchanger according to claim 4, further comprising: an outer periphery weir formed along the outer circumference of the through hole and having a height lower than the side plate formed on the outer circumference of the spray tray.

6. The three-fluid heat exchanger according to claim 1, wherein a plurality of slits are formed in parallel on the bottom plate of the spray tray, and sub-slits are formed between the slits so as to be parallel to the slits.

7. The three-fluid heat exchanger according to claim 6, further comprising: a pair of weirs formed along both inner edges of the sub-slits and having a height lower than the side plates formed on the outer circumference of the spray tray.

8. A humidity control device comprising a three-fluid heat exchanger according to any one of claims 1 to 7.

Images