US20090277621A1
2009-11-12
12/442,586
2007-09-18
Cooling element, with multiple cooling disks (16, 17) arranged in an array to restrict flow interspaces for the air to be cooled. Cooling disks (16) extending to the inlet side for the air to be cooled, and shorter cooling disks (17) not extending to the inlet side, are arranged alternating order.
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F28D15/00 » CPC main
Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
F28D15/00 » CPC main
Heat-exchange apparatus employing intermediate heat-transfer media or bodies
F28D1/0475 » CPC further
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, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag the conduits having a single U-bend
F28F1/32 » CPC further
Tubular elements; Assemblies of tubular elements; Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
F28F2215/04 » CPC further
Fins Assemblies of fins having different features, e.g. with different fin densities
F28F3/00 IPC
Plate-like or laminated elements; Assemblies of plate-like or laminated elements
The invention relates to a cooling element according to the introductory part of claim 1. More specifically, it relates to a cooling element with a number of cooling disks being assembled to provide restricted interspaces for air to be cooled.
When assembling cooling elements with disks or lamellas arranged in an air flow to be cooled, it is important to have an efficient exchange between air and metal. The distance between the cooling disks is adapted to the manufacturing, typically without optimization relative to the size.
For some purposes, the available space is restricted, requiring compact cooling elements.
The main object of the invention is to provide a cooling element having higher efficiency than corresponding prior art cooling elements.
The invention is stated in claim 1. This design provides a substantial increase in cooling and lowering the temperature of air passing through such a cooling element. This is believed to be due to an increased degree of collision at the cooling dishes due to the stepwise constriction of the width of the air slots.
The claims 2-4 state particular favourable features of the invention. More details will be given in the following description of embodiments of the invention.
The invention is now described with reference to the drawings, wherein
FIG. 1 shows a side view of an embodiment of the invention, with a cooling element with dishes on cooling tubes, while
FIG. 2 shows an enlarged section of the dishes of FIG. 1.
In FIG. 1 a cooling element 11 with end sections 12 and 13 is shown. Between the end sections 12 and 13, two U-shaped cooling tubes 14 and 15 connected to conduct a cooling medium are arranged. The cooling tubes 14 and 15 carry an array of cooling dishes 16 and 17 arranged in alternating order. The cooling dishes 16 extend over the total dishes 16 and 17 arranged in alternating order. The cooling dishes 16 extend over the total height of the cooling elements 11, and are connected to the cooling tubes 14, 15, while the remaining cooling dishes 17 extend half as far as the cooling dishes 16 and are mounted on the lower cooling tubes 14. The interspace between the cooling dishes be 9 millimeters in the upper part and 2.5-3 millimeters in the lower part. This means a substantial reduction of the interspaces relative to prior art cooling elements. This provides an increase in the heat transfer. The reason for this increase in efficiency is not clear, but it is believed to be due to the lower interspace creating increased molecular motion and consequently increased collisions between the air molecules.
Air molecules being cooled at the transfer from the wider to the narrower interspaces are believed to be getting an increased specific weight and thus have an increased fall velocity and simultaneously oscillate more slowly and create fewer collisions with the succeeding neighbouring molecules.
A reduction of the disk interspace to lower than ca. 2.5 millimetres will increase the risk of icing and clogging.
The cooling element 11 of the example has a vertical orientation of the interspaces, with a gravitational air flow. The cooling element according to the example can also be used in a forced flow cooling system with a fan. This provides more versatility.
The cooling element 11 according to the invention may be used for various cooling purposes, for technical uses and in housings and offices. It is suitable for cooling elements to be suspended over the goods to be cooled.
It is also possible to achieve corresponding advantages with other arrangements of stepwise restricted interspaces. Two or more short dishes can be used between each pair with full extension. Or multiple steps can be arranged, provided the narrowest interspaces are in the range 2.5 to 3 millimetre.
1. Cooling element, with multiple cooling disks (16, 17) arranged in an array to restrict flow interspaces for the air to be cooled, characterized in that cooling disks (16) extending to the inlet side for the air to be cooled, and shorter cooling disks (17) not extending to the inlet side, are arranged in alternating order.
2. Cooling element according to claim 1, characterized in that the shorter cooling disks (17) extend over about half the flow distance for the air through the cooling element.
3. Cooling element according to claim 1, characterized in that the distance between the cooling disks (16, 17) at the dense side of the cooling element (11) is 2.5 - 3 millimetres.
4. Cooling element according to claim 1, characterized in that from 3 to 4 different heights of disks are arranged, to provide stepwise narrowing interspaces.