This application is a U.S. National Phase of International Application No. PCT/EP2006/061270, filed Apr. 3, 2006, which designates the U.S. and claims priority to German Application No. 102005021554.8, filed May 10, 2005, the entire contents of each are hereby incorporated by reference.
The present invention relates to a heat exchanger having an open, tube-like housing and a conduit arranged therein that serves to duct a first heat-transfer fluid and which has an uncoiled length exceeding the length of the housing, which is open at both its front sides to allow a second heat-transfer fluid to flow through it, and to a refrigerating device in which a heat exchanger of said type is employed. A heat exchanger and refrigerating device of said type are known from U.S. Pat. No. 5,592,829.
In said known heat exchanger the conduit is embodied as a coil. The housing surrounding the coil forces the flow of the second heat-transfer fluid so it sweeps along the coil's entire length in order thus to achieve a high heat-exchange efficiency at a moderate throughput rate for the second heat-transfer fluid.
That, though, gives rise to the problem that, with the flow through the heat exchanger being substantially parallel to the coil's longitudinal axis, a considerable portion of the second heat-transfer fluid will pass through the heat exchanger without at all attaining close proximity to the conduit, while other parts of the flow will successively sweep along many turns in the coil and substantially heat up while doing so.
An object of the present invention is to improve the efficiency of a heat exchanger of the kind cited in the introduction.
That is inventively achieved by providing sections of the housing's surface area with passages at least in the region of a first front side.
Said passages will, depending on pressure conditions prevailing in the housing, allow second heat-exchange fluid to flow in or out. Its flow field within the housing will thus not be oriented purely in the longitudinal direction but will also have radial components so that conduit sections situated at a distance from the housing's open front sides such as, for instance, the turns in a coil or longitudinal sections of a conduit that is meander-shaped or arranged in at least one loop can also be flowed against by second heat-transfer fluid not yet heated (or, depending on the direction of the heat flow in the heat exchanger, not yet cooled) at another section of the coil or meander.
A favorable application all around the conduit within the housing of air not yet heated by other conduit sections will result if the passages having an opening cross-section that is either the same or different are advantageously disposed evenly distributed around the surface area's circumference. The passages' portion of the wall's surface will preferably reduce with increasing distance from a first front side of the housing. The streaming conditions and hence the transfer of heat from the conduit to a second heat-transfer fluid will be particularly favorable if, according to a preferred embodiment, the opening cross-section of the passages reduces with increasing distance from the first front side. One half of the housing adjacent to the second front side can be free from passages.
The heat exchanger is preferably provided with a fan for driving the second heat-transfer fluid's flow through the housing.
Said fan is located preferably on the second front side of the housing.
Referred to the second heat-transfer fluid's flow direction, said second front side is preferably a downstream side, meaning that the fan will suck the second heat-transfer fluid through the housing and the second refrigerant will flow entirely through the opening on the second front side so it can be taken from there and ducted to a further application.
The fan can alternatively also be located centrally in the housing, in which case it can be provided for a portion of the wall's surface occupied by the passages to reduce from both front sides of the housing towards the fan so that second heat-transfer fluid can enter the housing through the passages located upstream of the fan and exit the housing through the passages located downstream of the fan.
A further subject of the invention is a refrigerating device having a heat exchanger of the aforementioned type as a condenser. The second heat-transfer fluid is in that case generally air, whereas the first heat-transfer fluid is a refrigerant of the refrigerating device.
Further features and advantages of the invention will emerge from the following description of exemplary embodiments with reference to the attached figures.
The heat exchanger shown in
Three groups 11a, 11b, 11c of passages 12 have been punched into the metal sheet 5. The distance between adjacent groups of passages increases with increasing distance from the opening 6 so that the passages 12 will occupy a reducing portion of the surface of the metal sheet 5 with increasing distance from the opening 6. There are no passages 12 on the half of the metal sheet 5 adjacent to the opening 7.
The fan's operation produces a pressure gradient within the housing 2, meaning that the difference in pressure between the housing's interior and ambient area will increase along the housing's longitudinal axis the closer the fan is approached. The greater the difference in pressure is between the interior and exterior, the greater also will be the air throughput rate per unit of area of each passage 12. To insure that the turns are supplied with cool fresh air as evenly as possible, the passages 12 must therefore, as already mentioned above, occupy an increasingly smaller portion of the surface of the metal sheet 5 with increasing distance from the opening 6. Instead of increasing the distance between the groups 11a, 11b, 11c with increasing distance from the opening 6, as shown in
A variant embodiment of an inventive heat exchanger is shown in
To prevent air inside the housing 2 from flowing back from the downstream to the upstream side of the fan within the cross-sectional area lying outside the coil, a partition 14 is provided here that extends from the metal sheet 5 forming the external wall of the housing 2 at the height of the fan wheel 10 to the immediate vicinity of the coil.
Number | Date | Country | Kind |
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10 2005 021 554 | May 2005 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2006/061270 | 4/3/2006 | WO | 00 | 11/1/2007 |
Publishing Document | Publishing Date | Country | Kind |
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WO2006/120083 | 11/16/2006 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
2115288 | Smith | Apr 1938 | A |
2187066 | Youker | Jan 1940 | A |
2311947 | Kucher | Feb 1943 | A |
4321803 | Smith | Mar 1982 | A |
4335782 | Parker | Jun 1982 | A |
4592888 | Cornu et al. | Jun 1986 | A |
4953364 | Lee | Sep 1990 | A |
5592829 | Kim | Jan 1997 | A |
7121328 | McDonald et al. | Oct 2006 | B1 |
Number | Date | Country |
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2 085 143 | Apr 1982 | GB |
Entry |
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International Search Report PCT/EP2006/061270. |
Number | Date | Country | |
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20090090126 A1 | Apr 2009 | US |