DEVICE FOR CHILLING AIR
The invention relates to a device for chilling
Use is made in the classical manner of compression cooling devices for chilling air. Such compression cooling devices have the drawback however that they use a lot of energy.
It is an object of the invention to provide a device for chilling air in relatively inexpensive and energy-saving manner. This object is achieved according to the invention with a device for chilling an air flow, which device comprises: a heat exchanger comprising a set of first channels and a set of second channels, wherein each channel is defined by heat-exchanging walls such that heat is exchangeable between air flows flowing through the first and second channels; moistening means for applying moisture to the walls of the second channels; and - a housing for accommodating the heat exchanger and the moistening means, wherein the housing comprises: an air inlet for guiding a primary air flow into the first channels, a branch for separating the primary air flow flowing out of the first channels into a first part-flow and a second part-flow and for guiding the first part- flow into the second channels, and a discharge for separate discharge of the first part-flow flowing out of the second channels and of the second part-flow.
Because a chilling takes place in the second channels due to evaporation of the water, a chilling effect occurs in these second channels up to almost the wet bulb temperature, which provides the advantage that a considerable chilling effect can be realized in the heat
exchanger depending on the moisture content of the second part-flow.
In a preferred embodiment according to the invention, the heat exchanger comprises a number of hollow panels placed substantially parallel to each other, which panels comprise a number of first channels extending in a main direction of the panels and which bound the second channels pairwise between the panels. In another embodiment according to the invention a moisture-absorbing layer is arranged on the main surfaces of the panels.
The moisture-absorbing layer can herein be a cloth consisting substantially of fibres, the length of which decreases when they are moistened, which fibres extend in directions substantially parallel to each other and the end zones defined by the ends of the fibres are fixed at least over discrete zones relative to said outer surfaces .
Because the cloth consists of a fibre which when moistened becomes shorter in longitudinal direction, when the cloth is wound round the panel in the fibre direction it will hereby stretch tight round the panel when moistened, thereby ensuring a close contact of the cloth against the panel. Two mutually remote end zones of the cloth preferably overlap and are mutually connected in tensively strong manner in longitudinal direction of the fibres such that the outer end zone is directed upward relative to the plate. In a further preferred embodiment according to the invention, the cloth extends over at least a part of both main surfaces while covering the panel edge situated therebetween, between which cloth and which panel edge is situated a moisture-absorbing cord which is in direct and therefore moisture-exchanging contact with the cloth. A drop falling on the cord will hereby be spread over a certain width, whereafter it can soak into the moisture-
absorbing material. A very uniform distribution of the sprayed moisture is hereby obtained.
In yet another embodiment a cord is likewise arranged on the underside of a panel which spreads over a determined width possible drops which may form on the underside of the panel, whereby this moisture can still evaporate .
The cord is preferably a rolled-up cloth.
In yet another embodiment, the device comprises a collecting tray placed below the heat exchanger and a fine-mesh cloth or gauze arranged between the collecting tray and the heat exchanger, wherein the branch connects onto a space bounded by the cloth and the heat exchanger o' guide the first part-flow to the second channels. The first part-flow is supplied along the space formed between the panels and the gauze. Drops forming on the underside of the panels can fall through the gauze into the collecting tray. In this embodiment however, the first part-flow does not skim along the liquid surface in the collecting tray, whereby the first part-flow is not additionally moistened.
In yet another embodiment the moistening means comprise a so-called porous drip hose which is arranged on the panels, whereby the drops fall directly onto the moisture-absorbing material. It is hereby no longer possible for evaporation of the moisture on the drop surface of a drop situated in the air to take place. The moisture supply by means of such a hose can moreover be regulated well. In an embodiment the first part-flow is chilled and/or dried before it is guided through the second channels. The air of the first part-flow can hereby absorb more moisture, which enhances the evaporation of the moisture. The first part-flow will preferably have a relative air humidity which is lower than 80%.
The first part-flow is preferably guided in upward direction through the heat exchanger. The part-
flow will hereby not be hindered by the so-called chimney effect, whereby a better efficiency is obtained.
The moistening means can comprise sprayers, although in a preferred embodiment the moistening means comprise at least one tube which is open at the top along its length, and at least one cloth which is wrapped round the tube and protrudes into the tube, wherein the cloth is in direct and therefore moisture-exchanging contact with the cloth arranged on the panels. Figure 1 shows a perspective view of an embodiment of the invention;
Figure 2 shows a cross-sectional view of a second embodiment of the invention;
Figure 3 shows a perspective view of a third embodiment of a panel according to the invention;
Figure 4 shows a perspective view of a panel according to a fourth embodiment;
Figure 5 shows a cross-sectional view of a fifth embodiment of the invention; Figure 6 shows a perspective view of a sixth embodiment according to the invention;
Figure 7 shows a cross-sectional view of a panel according to a seventh embodiment.
Figure 1 shows schematically in perspective view a first embodiment of a chilling device 1 according to the invention.
Chilling device 1 comprises a housing 15 with a number of panels 2 placed mutually parallel. Each panel 2 has a large number of channels 3 which extend in length- wise direction of the panel. Arranged above panels 2 are a number of spray heads 4 which spray moisture V onto panels 2. This moisture V precipitates on the wall of panels 2 and runs downward along this wall 5 and subsequently falls into collecting tray 6. A primary air flow Lp is blown into channels 3 of panels 2 by means of an inlet 16. The primary air Lp then flows through panels 2 and exits again on the other side. In a branch 17 a part of this primary air is subsequently deflected into a
b first part-flow Se which is then guided along walls 5 of panels 2. This first part-flow Se will herein evaporate the moisture situated on walls 5, whereby the walls 5 cool. The primary air flow Lp flowing through panels 2 will also be chilled by these cooled walls 5. The part of the primary air flow Lp which is not used as first part- flow Se can subsequently be used as second part -flow St in order to chill an area.
Figure 2 shows a schematic cross-section of a second embodiment of the invention, wherein the panels corresponding with the first embodiment are designated with the same reference numerals. In this embodiment a water-absorbing material 7 is arranged on walls 5 of panels 2. Owing to this water-absorbing material 7, moisture coming from spray heads 4 is retained better on walls 5 of the panels. Less water is hereby used and the first part-flow Se can evaporate the moisture better. The moisture supply can optionally be controlled such that collecting tray 6 becomes superfluous. Figure 3 shows a perspective view of a panel of a third embodiment according to the invention. Arranged herein on panel 2 is a cord 8 which has a strongly absorbent and spreading action. A water-absorbing material 7 is again arranged over cord 8 and panel 2. A drop which falls onto the upper part 9 of panel 2 is spread over a determined width of panel 2 and will subsequently moisten a portion of the water-absorbing material 7 extending from the top to the bottom. A uniform moistening of panel 2 is hereby obtained. Figure 4 shows a perspective view of a fourth embodiment according to the invention. Panel 2 is herein provided with a cord 8 on both the top side 9 and the underside 10. Around this whole is wrapped a cloth 10. This cloth 10 is wrapped round panel 2 such that the end 11 is directed upward, whereby a drop which forms in the region of the overlapping ends of cloth 10 is absorbed once again into the cloth and cannot drop downward from the end. The cloth can be glued onto the panel along
discrete zones, or the cloth can be fused with the panel by local heating. The cord 8 on the underside 10 of the panel is arranged to spread moisture which may accumulate locally over a determined width of panel 2. Less moisture will hereby drip into collecting tray 6.
Cloth 10 is preferably manufactured from fibres which become shorter in longitudinal direction when moistened. The fibres extend substantially in one direction in the cloth. When the cloth is wrapped round panel 2 such that the fibres extend in height direction of panel 2, the cloth will be drawn tight round panel 2 when moistened. A good contact of cloth 10 against wall 5 of panel 2 is hereby obtained, whereby an optimal heat transfer between the moisture and the wall of panel 2 is obtained.
Such a cloth is commercially obtainable under the name Sorbo® as a cleaning cloth and consists mainly of viscose.
Figure 5 shows a schematic cross-sectional view of a fifth embodiment according to the invention. Used in this embodiment are panels 2 which are covered in the manner as shown in figure 4 with two cords 8 and a cloth 10. A collecting tray 6 is arranged under these panels 2. Between the underside of panels 2 and collecting tray 6 is arranged a fine-mesh gauze 12. A drop D which forms on the underside of panel 2 falls therefrom onto the gauze and then trickles therethrough, whereafter it falls into collecting tray 6. The first part-flow Se, which is here guided upward from along the bottom of panels 2, flows through the space bounded by the underside of panels 2 and gauze 12. The first part-flow Se will hereby not skim over the water surface situated in collecting tray 6 whereby undesired moistening of the first part-flow Se is prevented. Figure 6 shows a schematic perspective view of a sixth embodiment according to the invention. Chilling device 1 largely corresponds herein with the embodiment of figure 5. Moistening of panels 2 is however performed
here by means of a porous drip hose. Drip hose 13 lies on the top of panels 2 whereby drops forming on the hose are absorbed directly by the water-absorbing material 7 on panels 2. A uniform spread of the moisture over panels 2 is further obtained by cords 8. For an improved moisture distribution a cloth, for instance as applied on panels 2 , can be wrapped round the drip hose .
Figure 7 shows a cross-sectional view of a seventh embodiment according to the invention. A U-shaped tube 18 is herein placed on a panel as according to figure 3 or 4. This tube 18 is covered with a cloth 19, such as the Sorbo cloth. In tube 18 is a water level V in which the ends 20 of cloth 19 extend. Via these ends 20 the cloth 19 will absorb moisture and transfer it via transition 21 to the cloth 9 on the panel.
In advantageous manner the first part-flow Se can be dried and/or chilled before it is guided into the second channels, whereby the flow can absorb extra moisture. Drying can take place by means of an electrolyte which can be dried again by electric current. An alternative to the removal of moisture forming on the underside of panels 2 is to arrange a number of cords 22 as applied in the panels, which cords 22 extend transversely of panels 2 and lie against the underside of panels 2. The cords are arranged parallel at some mutual distance. Moisture forming on the underside of a panel 2 can thus be transported to adjacent panels, where the moisture is subsequently sucked into the moisture-absorbing layer 7 on the panels (see figure 8) .