The present invention relates to a method and apparatus for the disposal of heat utilizing a heat exchange liquid in combination with a heat exchange gas. More particularly, the present invention relates to an apparatus for providing an evaporative heat exchanger wherein the heat exchanger is employed, for example, to dispose of large quantities of heat generated by various industrial processes.
Evaporative heat exchangers are widely used in many applications where it is necessary to cool or condense fluid and/or gas that must be maintained out of contact with the heat exchange medium to which the heat is transferred. For example, air conditioning systems for large buildings employ evaporative heat exchangers for carrying out a portion of the heat exchange that is essential to the cooling process. In these systems, air inside the building is forced passed coils containing a cooled refrigerant gas thereby transferring heat from inside the building into the refrigerant gas. The warmed refrigerant is then piped outside the building where the excess heat must be removed from the refrigerant so that the refrigerant gas can be re-cooled and the cooling process continued. In addition, industrial processes such as chemical production, metals production, plastics production, food processing, electricity generation, etc., generate heat that must be dissipated and/or disposed of, often by the use evaporative heat exchangers. In all of the foregoing processes and numerous other processes that require the step of dissipating or disposing of heat, evaporative heat exchangers have been employed.
The general principle of the evaporative heat exchange process involves the fluid or gas from which heat is to be extracted flowing through tubes or conduits having an exterior surface that is continuously wetted with an evaporative liquid, usually water. Air is circulated over the wet tubes to promote evaporation of the water and the heat of vaporization necessary for evaporation of the water is supplied from the fluid or gas within the tubes resulting in heat extraction. The portion of the cooling water which is not evaporated is recirculated and losses of fluid due to evaporation are replenished.
Conventional evaporative heat exchangers are presently in widespread use in such areas as factory complexes, chemical processing plants, hospitals, apartment and/or condominium complexes, warehouses and electric generating stations. These heat exchangers usually include an upwardly extending frame structure supporting an array of tubes which form a coil assembly. An air passage is formed by the support structure within which the coil assembly is disposed. A spray section is provided usually above the coil assembly to spray water down over the individual tubes of the coil assembly. A fan is arranged to blow air into the air passage near the bottom thereof and up between the tubes in a counter flow relationship to the downwardly flowing spray water. Heat from the fluid or gas passing through the coil assembly tubes is transferred through the tube walls to the water sprayed over the tubes. As the flowing air contacts the spray water on the tubes, partial evaporation of some of the spray water occurs along with a transfer of heat from the spray water to the air. The air then proceeds to flow out of the heat exchanger system. The remaining unevaporated spray water collects at the bottom of the conduit and is pumped back up and out through the spray section in a recirculatory fashion.
Current practice for improving the above described heat transfer process includes increasing the surface area of the heat exchange tubes. This can be accomplished by increasing the number of coil assembly tubes employed in the evaporative heat exchanger by “packing” the tubes into a tight an array as possible, maximizing the tubular surface available for heat transfer. The tightly packed coils also increase the velocity of the air flowing between adjacent tube segments. The resulting high relative velocity between the air and water promotes evaporation and thereby enhances heat transfer.
Another practice currently employed to increase heat transfer surface area is the use of closely spaced fins which extend outwardly, in a vertical direction from the surface of the tubes. The fins are usually constructed from a heat conductive material, where they function to conduct heat from the tube surface and offer additional surface area for heat exchange.
In addition, another method currently used to increase heat exchange is the use of splash type fill structures placed between individual tubes in a coil assembly that can function to provide additional water surface area for heat transfer.
These current practices can have drawbacks. For example, the use of additional tubes requires additional coil plan area along with increased fan horsepower needed to move the air through the tightly packed coil assembly, increasing unit cost as well as operating cost. In addition, placement of fins between the individual tubes may make the heat exchanger more susceptible to fouling and particle build up. Further, indiscriminate placement of fill sheets within coils assemblies can cause performance degradation by hindering air flow, and the fill sheets can act as an insulator where they abut the tubes, and/or can cause heat already transferred to the air to be transferred back to the cooling water.
Accordingly, it is desirable to provide a method and apparatus for effectuating desirable, evaporative heat exchange that can offer a substantial reduction in parts, improved efficiency and or reduction of complex and costly assembly of components. It is also desirable to provide increased evaporative heat exchange without undesirably increasing the size of the unit, the manufacturing cost of the unit, and/or operating cost of the unit.
The foregoing needs are met, at least in part, by the present invention where, in one embodiment, an evaporative apparatus for use in a counter flow heat exchange assembly is provided having a plurality of generally vertical arrays adjacently spaced laterally to each other. Each of the individual arrays includes a plurality of generally horizontal conduits extending across the heat exchange assembly in spaced relation to each other at different vertical levels of the counter flow heat exchange assembly. The arrays additionally have connector portions that connect the vertically adjacent conduits to each other. The evaporative apparatus also includes a plurality of generally vertical partitions each extending between at least some of the conduits in each of the arrays and at least some of the partitions extending between less than all conduits of each of the arrays.
In accordance with another embodiment of the present invention, an evaporative apparatus for use in a counter flow heat exchange is provided having a means for exchanging heat from a substance to be cooled having a first height, and a means for spraying a cooling fluid onto the heat exchanging means. The evaporative apparatus additionally has a means for passing air over the heat exchanging means along with a means for partitioning the cooling fluid and the air. The partitioning means includes a plurality of generally vertical partitions each having a second height less than the first height of the heat exchanging means.
In accordance with yet another embodiment of the invention, an evaporative apparatus for use in a counter flow heat exchange assembly is provided having a plurality of generally vertical arrays adjacently spaced laterally to each other. The arrays are each arranged along respective generally vertical centerlines and include a plurality of generally horizontal conduits. The arrays each have a diameter and extend across the heat exchange assembly in spaced relation to each other at different vertical levels of the counter flow heat exchange assembly. The arrays have connector portions for connecting vertically adjacent conduits to each other, and the adjacent vertical arrays have a centerline-to-centerline distance therebetween that is greater than the diameter of each the conduits. The arrays additionally include a plurality of generally vertical partitions each extending between at least some conduits of each array.
In yet another embodiment of the present invention, an evaporative apparatus for use in a counter flow heat exchange assembly having a means for exchanging heat from a substance to be cooled, wherein the means includes a plurality of arrays of conduits is provided. The arrays have a first diameter and are spaced by a centerline to centerline distance between the conduits. In addition, the evaporative apparatus has a means for spraying a cooling fluid onto the heat exchanging means along with a means for passing air over the heat exchanging means. The evaporative apparatus also includes a means for partitioning the cooling fluid and the air and a means for spacing adjacent arrays such that they have a centerline to centerline distance therebetween that is greater than the first diameter of the conduits.
In accordance with yet a further embodiment of the invention, a partition for a heat exchanging apparatus having conduits in generally vertical arrays, is provided. The partition includes a plurality of saddle portions for engaging the conduits and a plurality of dimple portions for engaging the conduits. The saddle portions and dimple portion additionally provide spacing between laterally adjacent vertical arrays, wherein the saddle portions and the dimple portions are positioned in staggered vertical levels with respect to one another on opposed sides of the ribs. The partition additionally has a plurality of horizontal channels where portions of the partition have been removed. The channels are vertically spaced apart from one another and extend horizontally between said saddles.
In another aspect of the invention, a method is provided for heat exchange comprising the steps of: providing a heat exchange assembly having a plurality of generally vertical arrays adjacently spaced laterally to each other, the arrays each comprising a plurality of generally horizontal conduits extending across the heat exchange assembly in spaced relation to each other at different vertical levels of the heat exchange assembly, each array having connector portions that connect vertically adjacent conduits to each other; providing a plurality of generally vertical partitions each extending between at least some of the conduits in each of the arrays and between less than all conduits of each of the arrays; flowing a substance to be cooled through the conduits; spraying a fluid onto the partitions and the conduits; and passing air over the partitions and the conduits.
In yet another aspect of the present invention, a method for exchanging heat is provided comprising the steps of: exchanging heat from a substance to be cooled that passes through a plurality of conduits; spraying a cooling fluid onto the conduits; passing air over the conduits; and partitioning the cooling fluid and the air flow via at least one partition having a plurality of generally vertical partitions each having a second height less than the first height of the heat exchanging means.
In accordance with yet another aspect of the present invention, a method for exchanging heat is provided comprising the steps of: providing a heat exchange assembly having a plurality of generally vertical arrays adjacently spaced laterally to each other, the arrays each arranged along a respective, generally vertical centerline and the arrays each comprising a plurality of generally horizontal conduits extending across the heat exchange assembly in spaced relation to each other at different vertical levels of the heat exchange assembly, each array having connector portions for connecting vertically adjacent conduits to each other; providing a plurality of generally vertical partitions each extending between at least some conduits of each array, and adjacent ones of the vertical arrays have a centerline-to-centerline distance therebetween that is greater than the diameter of each said conduit; flowing a substance to be cooled through the conduits; spraying a fluid onto the vertical partitions and outer surfaces of the conduits; and passing air over the individual conduits.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Referring now to the figures wherein like reference numerals indicate like elements,
Referring now to
The walls and other structural elements that form vertical passage 13 are preferably formed from mill galvanized steel, but may be composed of other suitable materials such as stainless steel, hot dipped galvanized steel, epoxy coated steel, and/or fiber reinforced plastics (FRP). The fan unit 18 of the air current generator has an outlet cowl which projects through the side wall 28 and into the air passage 13 preferably above the base 20 and the collection basin therein.
As shown in
The cooling fluid spray assembly 14 includes a plurality of pipes and nozzles positioned directly above the coil assembly 11 for distribution of a cooling liquid, preferably water, onto the individual coil arrays 12 of the coil assembly 11. The water is supplied to the coil assembly 11 by way of the recirculation line 30 previously described and enters the spray assembly 14.
The mist eliminator 16 generally includes a multitude of closely spaced, elongated strips that are canted along their length and forms an opening through the top of the conduit 10 for the air currents to exit.
Referring now particularly to
As can be observed specifically in
The conduits 36 are preferably formed from copper alloy, however other materials suitable for conducting heat energy such as aluminum, steel and/or stainless steel derivatives may be utilized. As depicted, the conduits 36 are cylindrical in shape, however the tubes may vary in shape for example, square, oval, or rectangular. In addition, the cooling tubes 35 may vary in diameter. Although unitary tubes 35 are preferred, the horizontal conduits 36 may be individual tubes with a connector at each end providing fluid connection between vertically adjacent conduits. Also, the conduits 36 are preferably generally parallel to one another and generally horizontal. References to parallel and/or horizontal in this application refer to generally or substantially parallel and do not indicate any particular degree of the same.
As depicted in
As can be viewed in
The dimples 44 are further utilized for providing spacing between conduits of separate, laterally neighboring coil arrays 12. As illustrated in
The dimples 44 in combination with the ribs 40 provide a spacing distance between conduits of neighboring arrays that is preferably equal to approximately 110% to 150% the diameter of the conduits 36 utilized in the array 12. More preferably, this distance is about 130% the cooling tube diameter. Due to the above described spatial arrangement, a vertical clear line of sight exists through the coil assembly 11. This clear line of sight refers to the fact that two adjacent arrays 12 have a centerline distance (D) greater than the outer diameter (d) of the conduit 36 utilized, as depicted in FIG. 6. The aforementioned spacial relationship creates a vertical channel between the circuits that is free and unobstructed. As a result of this clear sight line, air flow through the coil assembly is not hindered and pressure loss is reduced.
The saddles 42 and dimples 44 combine to provide support to the fill sheets 38 along with providing a mechanism for attaching the sheets to the conduits 36. As a result of the aforementioned utilization of the vertical ribs 40 in combination with saddles 42 and dimples 44, the need for a separate mechanical attaching means to affix the fill sheet to the conduit 36 is eliminated. In addition, the need for attaching the fill sheet 38 to each individual conduit 36 with fixtures at a multitude of places is eliminated.
Referring now to
During operation of the evaporative heat exchanger 10, a fluid to be cooled or condensed, such as water or gas, flows into the exchanger 10 via an inlet port. This fluid is then distributed by the upper manifold to the individual arrays 12 that make up the coil assembly 11. The fluid being cooled then proceeds to flow through the various conduits 36, back and forth across the interior of the air passage 13 at different levels therein until it reaches the lower manifold where it is transferred out of the evaporative heat exchanger 10. As the fluid being cooled flows through the coil assembly 11, water is sprayed from the spray assembly 14 onto the fill sheets 38 and conduits 36 of each, separate array 12 while air from the air current generator 18 is blown up between the individual conduit tubes 36. The upwardly flowing air then passes through the mist eliminator 16 and out of the system.
More particularly, during its flow through the conduits 36, the fluid to be cooled gives up heat to the conduit walls of the conduits 36. The heat passes outwardly through the walls to the water flowing over the outer surface of the conduit. Meanwhile the water is simultaneously coming into evaporative contact with the upwardly moving air and the water gives up heat to the air both by normal contact transfer and by partial evaporation.
The present invention improves the aforementioned heat exchange process by increasing the heat exchange capabilities and affording the process to be more efficient. The addition of fill sheets 38 functions to provide increased air-water interface by producing more water surface area that may contact both the conduits 36 and the air currents. The fills sheets 38, in combination with the spacing of the cooling tubes previously described, create clear vertical sight lines through the coil assembly 11. This results in an increased, more efficient heat transfer without requiring increased coil plan area and/or air current generator horsepower. In addition, the fill sheets 38 function to direct water between cooling tubes 36, improving water flow over the entire tube surface, significantly reducing the likelihood of evaporative fouling and/or dry spots on the cooling tube surfaces. Another benefit of placing the fill sheets within the coil circuits is the sheets 38 allow the recirculating spray system to operate at lower flow rates, affording the heat exchange unit to employ pumps that are less expensive to purchase and operate.
As depicted in
To minimize this effect it is advantageous in some embodiments to employ the fill sheets 38 only between conduits 36 in lower and middle portions of the array 12 so that the sheets 38 do not extend between all vertically adjacent conduits, reducing the likelihood that heat will be transferred back from the air to the recirculating water, making the counter flow heat exchanger less efficient.
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirits and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
Number | Name | Date | Kind |
---|---|---|---|
3012416 | Dart et al. | Dec 1961 | A |
3050959 | Rich | Aug 1962 | A |
3290025 | Engalitcheff, Jr. | Dec 1966 | A |
4098331 | Ford et al. | Jul 1978 | A |
4102152 | Covault | Jul 1978 | A |
4112027 | Cates | Sep 1978 | A |
4196157 | Schinner | Apr 1980 | A |
4252752 | Flandroy | Feb 1981 | A |
4366106 | Benyak et al. | Dec 1982 | A |
4434112 | Pollock | Feb 1984 | A |
4544513 | Otterbein | Oct 1985 | A |
4683101 | Cates | Jul 1987 | A |
4693302 | Dodds | Sep 1987 | A |
4732585 | Lerner | Mar 1988 | A |
4755331 | Merrill et al. | Jul 1988 | A |
4758385 | Acker et al. | Jul 1988 | A |
5129446 | Beamer | Jul 1992 | A |
5174928 | Cheng et al. | Dec 1992 | A |
5178124 | Lu et al. | Jan 1993 | A |
5435382 | Carter | Jul 1995 | A |
5636527 | Christensen et al. | Jun 1997 | A |
5724828 | Korenic | Mar 1998 | A |
5927097 | Wright | Jul 1999 | A |
6176101 | Lowenstein | Jan 2001 | B1 |
6702004 | Stratman et al. | Mar 2004 | B1 |
Number | Date | Country |
---|---|---|
0 961 092 | Jan 1999 | EP |
Number | Date | Country | |
---|---|---|---|
20030192678 A1 | Oct 2003 | US |