Abstract
Enthalpy-exchanging unit comprising at least one plate along whose at least one contact side a first flowable medium and a second medium can travel while exchanging enthalpy, and which enthalpy-exchanging unit comprises at least one hygroscopic material layer, which connects to at least one contact side, in contact with the first flowable medium, of the plate, wherein the mutual orientation of the plate and the material layer is such that a liquid film of the first medium can form between the plate and the material layer, wherein the liquid film is in enthalpy-exchanging contact with both the plate and the material layer, characterized in that the material layer is fastened to the plate with a plurality of seams, which extend substantially parallel to one another and are continuous, such that a plurality of channels separated from one another by the seams are formed over the contact side of the plate, with the aim of increasing the degree of spread of the first flowable medium over the contact side of the plate, and thus, on the one hand, reducing the influence of cohesion between the liquid molecules and the accompanying surface tension and, on the other hand, increasing the influence of the adhesion between the flowable medium and the plate, wherein an more even liquid supply without the use of nozzles is secured, by on the top side a supply unit provided with a porous, absorbent bed.
Claims
1. An enthalpy-exchanging unit, comprising: at least one plate along whose at least one contact side a first flowable medium and a second medium can travel while exchanging enthalpy, and at least one hygroscopic material layer, which connects to at least one contact side, in contact with the first flowable medium, of the plate, wherein the mutual orientation of the plate and the material layer is such that a liquid film of the first medium can form between the plate and the material layer, wherein the liquid film is in enthalpy-exchanging contact with both the plate and the material layer, and wherein the material layer is fastened to the plate with a plurality of seams, which extend substantially parallel to one another, are continuous, and are arranged at a centre-to-centre distance apart, such that a plurality of channels separated from one another by the seams are formed over the contact side of the plate.
2. The enthalpy-exchanging unit according to claim 1, wherein the plate comprises a peripheral margin whereto the seams extend in the longitudinal direction at at least one end.
3. The enthalpy-exchanging unit according to claim 2, wherein the seams extend in the longitudinal direction at one end up to a certain distance away from the peripheral margin of the plate, wherein the distance preferably conforms to the centre-to-centre distance between the seams.
4. The enthalpy-exchanging unit according to claim 1, wherein the seams bind merely the surface of the plate-facing side of the material layer to the plate, wherein the seams only partially penetrate the material layer.
5. The enthalpy-exchanging unit according to claim 1 wherein the plate is made of a plastic, preferably a thermoplastic polymer.
6. The enthalpy-exchanging unit according to claim 1 wherein the centre-to-centre distance between the seams is between 30 and 80 mm and preferably between 40 and 60 mm.
7. The enthalpy-exchanging unit according to claim 1, wherein the centre-to-centre distance between the seams is between 30 and 80 mm and preferably between 30 and 50 mm, wherein the centre-to-centre distance between the seams for seam pairs which during use succeed one another in the gravitational direction decreases.
8. The enthalpy-exchanging unit according to claim 1 wherein the seams in the longitudinal direction, and preferably in the middle between their respective ends, comprise at least one interruption, wherein the total interruption is appreciably smaller than the total length of the seam.
9. The enthalpy-exchanging unit according to claim 1 further comprising seams extending at right angles to one another.
10. Enthalpy exchanger comprising at least one enthalpy-exchanging unit according claim 1.
11. The enthalpy exchanger according to claim 10, wherein above a side, defined in correct usage as the top side, of the at least one enthalpy-exchanging unit is arranged a liquid supply unit for supplying the first flowable medium between the plate and the material layer under the effect of gravity.
12. The enthalpy exchanger according to claim 11, wherein the liquid supply unit comprises a porous, absorbent bed made of a plastic.
13. The enthalpy exchanger according to claim 11, wherein the seams extend in the longitudinal direction at one end to a part, facing the liquid supply unit, of the peripheral margin of the plate.
14. The enthalpy exchanger according to claim 13, wherein the seams extend substantially in the gravitational direction, such that the first flowable medium, under the effect of gravity, can travel downwards through the plurality of channels separated from one another by the seams.
15. The enthalpy exchanger according to claim 10, wherein the seams extend, in correct usage of the enthalpy exchanger, in a substantially horizontal direction.
16. The enthalpy exchanger according to claim 15, wherein the seams extend in the longitudinal direction at a first end, in turns, to a first side of the peripheral margin of the plate, or a second side opposite the first side of the peripheral margin of the plate, wherein the seams extend in the longitudinal direction at a second end opposite the first end up to a certain distance from the peripheral margin of the plate.
17. The enthalpy exchanger according to claim 10, wherein the at least one enthalpy-exchanging unit at least partially delimits at least one passage for the feed-through of the second medium.
18. The enthalpy exchanger according to claim 17, wherein the at least one passage is at least partially delimited by that side of the enthalpy-exchanging unit which lies opposite the contact side in contact with the flowable medium.
19. The enthalpy exchanger according to claim 18, wherein a fraction of the second medium, having passed through the at least one passage, is conducted along the hygroscopic material layer.
20. A method for producing an enthalpy-exchanging unit according to claim 1, comprising: A) the positioning of at least one hygroscopic material layer relative to at least one plate, B) the connection of the at least one hygroscopic material layer and the at least one plate through the simultaneous arrangement of continuous seams, extending substantially parallel to one another, between the at least one hygroscopic material layer and the at least one plate.
21. The method according to claim 20, wherein the seams are formed by a connection technique chosen from the group comprising welding, gluing or stitching.
22. The method according to claim 20, wherein, during step B), the seams are merely connected to the surface of the plate-facing side of the material layer, wherein the seams only partially penetrate the material layer.
Description
[0028] The invention will be illustrated on the basis of non-limiting illustrative embodiments represented in the following figures, in which:
[0029] FIG. 1 shows a perspective view of an enthalpy-exchanging unit in accordance with the invention,
[0030] FIG. 2 shows an exploded perspective view of an enthalpy exchanger in accordance with the invention,
[0031] FIG. 3 shows a schematic view of an embodiment of an enthalpy-exchanging unit in accordance with the invention,
[0032] FIG. 4 shows a cross-sectional view along the line A-A in FIG. 3,
[0033] FIG. 5 shows a schematic view of another embodiment of an enthalpy-exchanging unit in accordance with the invention,
[0034] FIG. 6 shows a cross-sectional view along the line B-B in FIG. 5,
[0035] FIG. 7 shows a schematic cross-sectional view of an embodiment of the enthalpy exchanger in accordance with the invention,
[0036] FIG. 8 shows a schematic cross-sectional view of another embodiment of the enthalpy exchanger in accordance with the invention,
[0037] FIG. 9 shows a schematic cross-sectional view of yet another embodiment of the enthalpy exchanger in accordance with the invention,
[0038] FIG. 10 shows a schematic cross-sectional view of still another embodiment of the enthalpy exchanger in accordance with the invention,
[0039] FIG. 11 shows a schematic representation of a wet-bulb cooling or adiabatic cooling process which is used in an enthalpy exchanger in accordance with the invention,
[0040] FIG. 12 shows a schematic representation of yet another wet-bulb cooling or adiabatic cooling process which is used in an enthalpy exchanger in accordance with the invention.
[0041] FIG. 1 shows a perspective view of an enthalpy-exchanging unit 1 in accordance with the invention. The enthalpy-exchanging unit comprises a plurality of plates 2, which are held at a distance apart by spacers. A first flowable medium, often salt water, brackish water or salt (sea) water, and a second medium, often air, can travel along contact sides 3 of plates 2 while exchanging enthalpy. Should the enthalpy-exchanging unit 1 be used in a dew point cooling process, the second medium will travel in the direction of the arrows q.sub.v along the plates 2. The plates 2 are wrapped with a hygroscopic material layer 4, such that the material layer connects to the contact sides 3. Between each of the plates 2 and the material layer 4 is left a space, within which the first flowable medium can form a liquid film which is in enthalpy-exchanging contact with both the plate and the material layer. The material layer 4 is fastened to the plate with a plurality of continuous seams 5 extending substantially parallel to one another, such that a plurality of channels 6 separated from one another by the seams are formed over the contact side of the plate. The width of each of the channels is herein defined by the centre-to-centre distance 7 between the seams 5. Where the seams 5 extend at a first end to the peripheral margin 9 of the plate 2, the seams 5 extend at a second end up to a certain distance 8 from the peripheral margin 9 of the plate 2. This distance 8 preferably the surface
[0042] FIG. 2 shows an exploded perspective view of an enthalpy exchanger 10 in accordance with the invention. The enthalpy exchanger 10 comprises a plurality of side-by-side enthalpy-exchanging units 1 of the type discussed above. On the top side of the enthalpy exchanger is placed a liquid supply unit 11, provided with a porous, absorbent bed 12, made of plastic, which makes evenly distributed water supply possible without the use of nozzles, thereby preventing cleaning, malfunction and maintenance of the nozzles. The liquid supply unit is designed to supply the first flowable medium to the channels 6 formed between the plates 2 and the material layers 4 by the continuous seams 5. Since the seams 5 extend in the gravitational direction over the plates 2, the first flowable medium, under the influence of gravity and with the aid of the hygroscopic material layer 4, will flow downwards via the channels 6, whereby a liquid film is formed between the plates 2 and the material layers 4 of the enthalpy-exchanging units. That embodiment of the enthalpy exchanger which is shown in FIG. 2 uses a dew point cooling process to cool the second medium (in this case air). The air stream 13 to be cooled enters in the direction of the arrows q.sub.v and is subsequently guided by passages 14 along those sides of the enthalpy-exchanging unit 1 which lie opposite the side in contact with the flowable medium (in this case water). During this process, heat transfer of the air to be cooled takes place at the plates 2, whereby the air of the conditioned air stream 15, upon leaving the passages 14, has been reduced in temperature, whilst the absolute moisture content remains constant. A fraction (in this case one-third) of the conditioned air stream 15 is returned as the process air stream 16 along passages 17, along that side of the enthalpy-exchanging unit 1 which is in contact with the water. During this return travel, the process air stream 16 absorbs the moisture evaporating from the hygroscopic material layer 4 which has been kept moist. The heat required for the evaporation is hereupon at least partly extracted from the air stream 13 to be cooled, which is guided along the side lying opposite that side of the enthalpy-exchanging unit 1 which is in contact with the water. During return travel, the process air stream 16 also absorbs heat, whereby this is a case of a diabatic process. Following the absorption of both heat and moisture from that side of the enthalpy-exchanging unit 1 which is in contact with the water, the process air stream is evacuated to the atmosphere.
[0043] FIG. 3 shows a schematic view of the contact side 3 of an embodiment of an enthalpy-exchanging unit in accordance with the invention. In this embodiment, the seams 5 are arranged in a substantially horizontal direction on the enthalpy-exchanging unit. In addition, an interruption 18 is arranged in the seams for the evacuation of any air which might accumulate in the channels 6.
[0044] FIG. 4 shows a cross-sectional view along the line A-A in FIG. 3. The shown enthalpy-exchanging unit comprises a plurality of plates 2, which are held at a distance apart by spacers and are wrapped with a hygroscopic material layer 4. The plate 2 and the material layer 4 are connected to each other by means of seams 5, which are arranged at a centre-to-centre distance 7 from one another.
[0045] FIG. 5 shows a schematic view of the contact side 3 of another embodiment of an enthalpy-exchanging unit in accordance with the invention. In this embodiment, the seams 5 extend substantially in the gravitational direction. It can also be seen that the seams 5 extend at a first end to the peripheral margin 9 of the plate 2 and extend at a second end up to a certain distance 8 from the peripheral margin 9 of the plate 2.
[0046] FIG. 6 shows a cross-sectional view along the line B-B in FIG. 5. The shown cross-sectional view likewise reveals that the enthalpy-exchanging unit comprises a plurality of plates 2, wrapped with a hygroscopic material layer 4.
[0047] FIG. 7 shows a schematic cross-sectional view of an embodiment of the enthalpy exchanger in accordance with the invention. The enthalpy exchanger 10 comprises an enthalpy-exchanging unit 1, above which a liquid supply unit 11 is arranged. On the bottom of the liquid supply unit 11 is arranged a porous, absorbent layer or bed 12, made of a plastic, for supplying the first flowable medium 19 in a spread manner over the channels 6 of the enthalpy-exchanging unit. Via the seams arranged in the gravitational direction, here helped by the hygroscopic layer and gravity, the first flowable medium flows downwards along the plate, whereafter the excess of supplied flowable medium is evacuated via a drain 20.
[0048] FIG. 8 shows a schematic cross-sectional view of another embodiment of the enthalpy exchanger 10 in accordance with the invention. Similar to the enthalpy exchanger shown in FIG. 7, multiple parallel seams 5 are arranged in a substantially vertical direction, to allow the first flowable medium 19 to flow in the gravitational direction downwards along the plate, upon which the excess of supplied flowable medium 19 is evacuated via a drain 20. Different from the enthalpy exchanger shown in FIG. 7, two separate liquid supply units 11 are arranged above the enthalpy-exchanging unit 1 that together connect to only a part of the upper side of the enthalpy-exchanging unit 1 instead of covering said upper side substantially entirely. The remaining free part of the upper side of the enthalpy-exchanging unit 1 can then be used as a passage for process air 16. In the shown configuration, the process air steam 16 is guided over the enthalpy-exchanging unit 1 in a substantially perpendicular direction with respect to the conditioned air stream 15. To guarantee an even distribution of the first flowable medium 19 over the multiple parallel, vertically extending channels 6, the material layer is fastened to the plate 2 with an addition horizontally extending seam 5, provided above said vertically extending channels 6. The first flowable medium 19 is fed to the horizontal channel 6 that is formed above the horizontally extending seam 5 in an even and controlled fashion by the use of a porous, absorbent layer or bed 12 provided in the liquid supply units 11. The horizontally extending seam 5 hereby prevents the first flowable medium 19 from flowing down immediately. By contrast, the first flowable medium 19 is evenly spread over the multiple vertically extending channels 6 through an outflow in vertical direction via interruptions 18 in the horizontally extending seam 5.
[0049] FIG. 9 shows a schematic cross-sectional view of yet another embodiment of the enthalpy exchanger in accordance with the invention. In contrast to the embodiment shown in FIG. 7, the seams 5 are now arranged in a substantially horizontal direction on the enthalpy-exchanging unit 1. In addition, the seams 5 extend in the longitudinal direction at one end to the peripheral margin 9 of the plate 2, whilst the same seams 5 extend at their other end up to a certain distance from the peripheral margin 9 of the plate 2. As a result hereof, the separate channels 6 delimited by the seams form an unbroken zigzag-shaped channel. The liquid supply 11 at one edge connects to only a part of that side of the at least one enthalpy-exchanging unit 1 which is defined in correct usage as the top side, in order thus to provide liquid to the topmost channel 6 formed by the seams 5. Under the effect of gravity, the liquid will be conducted along the underlying channels, whereby the supplied first flowable medium 19 is distributed over the entire surface of the plate 2. The other part of the top side of the enthalpy-exchanging unit 1 can hereby be used as a supply of process air 16, which can thereby be conducted also from the top side along the liquid film formed by the first flowable medium 19. Interruptions 18 are arranged in the seams for the evacuation of any air which might accumulate in the channels 6.
[0050] Finally, FIGS. 10-12 show a schematic representation of a wet-bulb cooling process or adiabatic cooling process which is used in an enthalpy exchanger 10 in accordance with the invention. FIG. 10 shows an enthalpy exchanger in which the air stream to be cooled flows from left to right along the one or more enthalpy-exchanging units, whereby the air stream 13 to be cooled enters the enthalpy exchanger 10 on the left and leaves the enthalpy exchanger 10 as a conditioned (cooled) air stream 15. The process air stream 16 flows in an opposite direction substantially from right to left along the one or more enthalpy-exchanging units. FIG. 11 shows a wet-bulb cooling process or adiabatic cooling process which is identical to the process shown in FIG. 10, except that the process air stream 16 is guided over the one or more enthalpy-exchanging units in a substantially perpendicular direction with respect to the air stream 15 to be cooled 13 and conditioned. FIG. 12 shows a wet-bulb cooling process or adiabatic cooling process identical to the process shown in FIG. 11, with the exception that the first flowable medium 19 is supplied via two separate liquid supply units 11 on either side of the top side of the enthalpy-exchanger 10.
