CA1074649A - Heat exchanger exhibiting improved fluid distribution - Google Patents
Heat exchanger exhibiting improved fluid distributionInfo
- Publication number
- CA1074649A CA1074649A CA279,059A CA279059A CA1074649A CA 1074649 A CA1074649 A CA 1074649A CA 279059 A CA279059 A CA 279059A CA 1074649 A CA1074649 A CA 1074649A
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- Canada
- Prior art keywords
- panel
- constrictions
- connecting portions
- heat exchange
- entry
- Prior art date
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- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A heat exchange system comprising a plurality of passageways for a heat exchange medium defining opposes header structures connected by connecting portions of said passageways extending therebetween, said connecting portions having entry and exit portions communicating with said headers to provide ingress and egress openings for said heat exchange medium, wherein said connecting portions are provided with at least one constriction in internal diameter extending along at least a portion of the length of at least one of said connecting portions, said constriction serving to regulate the flow of said heat exchange medium between all of said connecting portions.
A heat exchange system comprising a plurality of passageways for a heat exchange medium defining opposes header structures connected by connecting portions of said passageways extending therebetween, said connecting portions having entry and exit portions communicating with said headers to provide ingress and egress openings for said heat exchange medium, wherein said connecting portions are provided with at least one constriction in internal diameter extending along at least a portion of the length of at least one of said connecting portions, said constriction serving to regulate the flow of said heat exchange medium between all of said connecting portions.
Description
BACKGROU7.~D OF THE INVENTION
The present invention relates to heat exchange systems compris~ng a plurality of internal tubular passageways disposed in a spaced apart relation to each other, which possess utillty in heat exchange applications wherein a heat exchange medium is circulated through the passageways.
A partlcular application of such a system resides in devices u~ilizing solar energy, and specifically~ solar energy absorbing devices for elevatlng fluid temperature.
It is well known that the radiatlon of the sun can be collected as a source o~ energy L or heatin~ or cooling or for direct conversion to electricity. Heating and cooling depend upon collection of rays of solar energy in a fluid heating transfer system. The heated fluid is pumped or allowed to flow to a place of utilization for the thermal energy it has acquired.
In certain areas of the world, solar energy is the most abundant ~orm of available energy if it could be har-nessed economically. Even in more developed areas of the world, the economic harnessing of solar energy would provide an att~active alternative to the use of fossile fuels for energy generation.
One of the problems attending the development of an efficient system for the conversion of solar energy resides with the structure and design of the solar energy absorbing device, or solar collector. This solar collector generally comprises a rectangular plate-like structure possessing channels or passageways for the circulation of the energy absorbing fluid medium. Conventionally, these panels have comprised a pair of opposed expanded passageways, known as ~07~4~
headers, which are placed at oppostte ends o~ the panel, and are connected by a plurality of tubular passageways which are often in parallel relation with respect to each other.
These passageways, as well as the headers themselves, have generall~ been disposed at right angles with respect to each other and in parallel relation with respect to the horizontal and vertical dimensions, respectively, o~ the panel.
Difficulty encountered with known solar collectors re-lates to the uniformity of distribution of the heat exchange fluid through the several connectir.g tubular passageways lying between the headers. Though fluid would ideall~J
pass through the individual connector tubes unlformly with respect to velocity, small variations in tube width, tube height and particular travel distar.ce from header to header cause variations in flow rate due to pressure drop through the ~ndividual connector tubes. Such variations a~ect the ~low rate and the heat collection rate of the connector tubes and the panel as a whole.
The above problem becomes particularly acute in the instance where collector systems comprlsing a plurality o~ panels~ which may be placed in either parallel or serial relation to each other are employed. In such systems, . .
tne pressure drop experienced within the individual panels is compounded b~y the pressure drop and unequal flcw occurring between the panels as fluid ~lows from the central manifold or header structure.
SU~ARY OF THE INVENTION
In accordance with the present invention, a heat ex-~07~649 changer is provided which possesses signi~icantly improved efficiency, and specific utility in solar energy applica tions.
The present invention comprises a system o~
tubular passageways for a heat exchange medium defining opposed header structures connected by connecting portlsns of said passageways extending therebetween, said connecting portions having entry and exit portions communicating wi~h said headers to provide ingress and egress openings for said heat exchange medium, wherein said connecting portions are pro~ided with at least one constriction in internal diameter extending along at least a portion of the length of at least one CL said connecting portions to assist in t~e dis-trlbution cf flow o~ said heat e~change medium.
The system of the present invention may comprise a central inlet manifold or header structure which connects at one or more points to a plurality of connecting portions which may, in one embodiment, comprise individual heat exchange panels. The individual panels may define a wide variety of patterns of passageways including one or more entry or exit portions, wherein at least one constriction is p-r~vided a}ong a portion of at least one of said entry or exlt portlons.
In a partlcular embodimentj the present invention may comprise a system of internal tubular passageways for a heat exchange medlum, said internal passage-h2ys contained within an indlvidual panel and disposed between spaced apart portions of the thickness of the panel to define opposed ln.~ern21 headers connected by internal connecting portions of said passageways extending therebetween. The 6~L~
lnternal passageways are provided with entry and exit portlons extending from the headers to opposed edges of the panel in order ko provide ingress and egress openlngs for the heat exchange medium. The internal connecting portions are modified by the provision of at least one constriction in internal diameter located on at least a portlon of the length of at least one of said connecting portions which assists in maintaining uniform flow of heat exchange fluld through said connecting portions.
The system of the present invention exhibits improved fluid flow and heat exchar.ge efficiency by the allocation of flow through the connecting portions achieved with the constrictions provided therein. The size, number and location of said constrictions may vary accord~ng to the size, disposition and number of the connecting portions employed.
As indicated above, the preferred embodiment of the present invention utilizes, as at least a part thereof, a metal panel having a system o~ internal fluid passageways, conventionally painted blackg as will be described in more detall here~nbelow. The concepts of the present invention may, however, also be advantageously utilized in heat exchangers generally, such as, for example, using extrusions.
Since the concepts of the present invention are particularly advantageous in metal panels having a system of internal fluid passageways, the present invention will be specifically described hereinbelow utilizing this type of system.
Accordingly, it is a principal ob~ect of the present invention to provide a heat exchange system which enables the efficient and economical transfer of heat energy.
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It is a further object of the present invention to provide a system as aforesaid which is particularly suited for use in solar energy collection.
It is yet a further object of the present invention to provide a system as aforesaid which is contained within a single metal panel and is efficiently designed to allow maximum utilization of internal passag~way systems for solar energy collection.
In accordance with a specific embodiment, a heat exchange system for use in a solar energy collector system comprises a plurality of passageways for a heat exchange medium dafining opposed header structures connected by a plurality of spaced, parallel individuai connecting portions of said passage-ways extending therebetween, said passageways having entry and exit portions extending from said header structures to provide ingress and egress openings for said heat exchange medium, wherein ~aid connecting portions are provided with a plurality of con~trictions in internal diameter extending along at least a portion of the length thereof wherein at least one of said constrictions ha~ differing internal diame~er ~o that the con-striction adjacent the area of greatest turbulence and fluid flow has the smallest internal diameter over at least a portion of its length and the constrictions on individual connecting portions have gradually increasing internal diameter .in relation to increased distance from said area of greatest turbulence, said constrictions serving to divert fluid away from the connect-ing portion receiving the primary amount of flow and to regulate the rate of flow of said heat exchange medium between all of said connecting portions.
In accordance with a further embodiment, there is provided, in a solar energy collector system including at least 46~9 one heat exchange panel possessing a syotem of internal tubular passageways defining opposed h~aders connec~d by a plurality of spaced, parallel individual connecting portions of said passageways extending therebetween, said passageways including entry and exit portions extending from opposite ends of said headers to provide ingress and egress openings for a heat exchange medium, the improvement which comprises providing said connecting portions with a plurality of constrictions in internal diameter extending along at least a portion of the length thereof wherein at least some o~ said constrictions have differing internal diameter so that the constriction adjacent said entry portion has the smallest internal diameter over at least a portion of its length and the constrictions on individual connecting portions have gradually increasing internal diameter in relation to increased distance from said entry portion, said constrictions serving to divert fluid away from the connecting portion adjacent said entry portion to regulate the rate of flow of said heat exchange medium between said connecting portions.
In accordance with a still further embodiment, a metal panel for use in a solar energy collector system has a desired system of internal tubular passageways for a heat exchange medium disposed between spaced apart portions of the thickness of said panel and defining opposed internal headers connected by a plurality of spaced, parallel individual internal connecting portions o~ said passageways extending therebetween, said internal passageways having entry and exit portions extend-ing from said internal h~aders to opposed edges of said panel to provide ingress and egress openings for said heat exchange medium, w~erein said connecting portions are provided with a plurality of constrictions in intçrnal diameter extending along ,.,. ;~
5a ~
.!
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at least a portion of the length thereof wherein at least some of said constrictions have differing internal diameter so that the constriction adjacent said ~ntry portion has the smallest internal diameter over at least a portion of its length and the constrictions on individual connecting portions have gradu-ally increasing internal diameter in relation to increased distance from said entry portion, said constrictions serving to divert fluid away from the connecting portion adjacent said entry portion to regulate the rate of flow of said heat exchange medium between all of said connecting portions.
Further objects and advantages will become apparent to those skilled in the art as a detailed description proceeds with reference to the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagram schematically depicting a heat exchange system representative of the present invention.
Figure 2 is a perspective view of a sheet of metal having a pattern of weld-inhibiting material applied to a surface thereof.
Figure 3 is a perspective view of a composite metal blank wherein a second sheet of metal is superimposed on the sheet of metal shown in Figure 2 with khe pattern of weld-inhibiting material sandwiched therebetween.
Figure 4 is a schematic perspective view showing the sheets of Figure 3 being welded together while passing through a pair of mill rolls.
Figure 5 is a top view showing a panel useful in the present invention having internal tubular passageways disposed batween ~paced apart portions of the thickness of the panel in the areas of the weld-inhibiting material.
Figure 6 is a sectional view taken along lines 6-6 of Figure 5.
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Figure 7 is an alternate view showing a variation in the tube configuration similar to the view of Figure 6.
Figure 8 is a blown-up perspective view showing the system of Figure l in greater detail utilizing as connecting portions the panel of Figure 5.
Figures 9-13 are top views showing alternate embodi-ments of the invention illustrated in Figure 5.
DETAILED DESCRIPTION
In accordance with the present invention, the fore-going objects and advantages are readily attained.
The system of the present invention is provided with a flow regulating mechanism in the form of at least one con-striction provided in at least one connecting portion extend-ing at least a portion of the length of said connecting portion which serves to regulate the flow of heat exchange medium between the connecting portions extending from and between the opposed header structures or manifolds.
The present invention deals with the problem of non-uniform flow resulting from excessive pressure drop occurring under the turbulent operating conditions to which the heat exchange systems are su~jected. Specifically, the systems are conventionally installed in the vertical plane whereby the inlet opening is located above the connecting portions. Fluid flows at a rate accelerated by gravity from the header into the entry portions, where it is then split into a plurality of channels defined by the remainder of the connecting portions to follow through the system. As noted earlier, nonuniform flow often results from irregularities in the size and shape of the connecting portions because of the pressure drop which develops therein. This pressure drop, in certain instances, causes air pockets to develop which impede the movement of ,. ... .
~L~)7~64~
heat exchange fluid. To this end, the provision of controlled restriction in the internal diameter of the connecting por-tions by the employment of the present invention serves to efficiently distribute fluid flow and prevent the development of the detrimental pressure differential.
The present invention is preferably utilized as a solar heating system as shown in Figure 1, and in greater detail in Figure 8, wherein a plurality of panels of the present invention 10 are mounted on roof 11 of building 12 with conduits 13 and 14 connected in any convenient fashion to the equipment in the building, with the connections no-t shown. Thus, for example, cold water may go into conduit 13 from the building 12 by means of a conventional pump or the like. The water flows from conduit 13 to common manifold or header structure 13a and is distributed into a plurality of parallel-directed connecting portions of said system comprisin~ in the illus-tration panels 10. The water flows through panels 10, is heated by means of solar energy, is collected in common mani-fold or header structure 14a and flows into conduit 14. The heated water is then stored or utilized in a heat exchange system inside the building in a known manner Naturally, if desired, the water flow may be reversed with the cold water entering via conduit 14 and collected via conduit 13. Al-ter-natively, the solar heating unit of the present invention may be used or placed in any suitable environment, such as on the ground with suitable fasteners -to prevent displacement by wind or gravity.
The solar heating unit of the present invention may be used for residential heating purposes, such as in providing hot water in a residential environment. For example, three of the illustrated panels having dimensions of 8 feet x 4 feet .. . ~, -- ~0~46i~L~
would efficiently supply an average household of four with hot water for home use. Alternatively, the system of the present invention may be conveniently used for heating water for swim-ming pools or for preheating water for domestic gas or oil fired domestic hot water heaters. The fluid is preferably retained in a closed systern with the water in the system heated in the solar unit and delivered into an insulated cistern or container so that the heated fluid may be stored up during sun-shine for use on cool cloudy days or at night when the heating of the fluid in the panel will not be of sufficient degree to provide the desired heat at the point of use.
A thermostat not shown is desirably installed at the top of the solar heater and this thermostat may be set to turn on a circulating pump whenever the temperature reaches a pre-determined reading. The pump will then pump the water through the system as generally outlined above.
As indicated above, the present invention may employ as the energy collector structure, one or more connecting por-tions comprising a metal panel of a particularly preferred design and construction for optimum efficiency in the solar heating system as described above. The metal panel is desir-ably fabricated by the ROLL-BOND~ process as shown in U. S.
Patent 2,690,002. Figure 2 illustrates a single sheet of metal 20 as aluminum or copper or alloys thereof, having applied to a clean surface 21 thereof a pattern of weld-inhibiting material 22 corresponding to the ultimate desired passageway system. Figure 3 shows the sheet 20 having super-imposed thereon a second sheet 23 with a pattern of weld-inhibiting material 22 sandwiched between the units, The units 20 and 23 are tacked together as by support welds 24 to prevent relative movernent between the sheets as they are ~ ~L079L6~19 subsequently welded together as shown in Figure a by passing through a pair of mill rolls 25 to form weld0d blank 26. It is normally necessary that the sheets 20 and 23 be heated prior to passing through the mill rolls to assure that they weld to each other in keeping with techniques well known in the rolling art.
The resultant blank 26 is characterized by the sheets 20 and 23 being welded together except at the area of the weld-inhibiting material 22 The blank 26 with the unjoined inner portion corresponding to the pattern of weld-inhibiting material 22 may then be softened in any appropriate manner as by anneal-ing, and thereafter the blank may be cold rolled to provide a more even thickness and again annealed. The portions of the panel adjacent the weld-inhibiting material 22 are then in-flated by the introduction of fluid distending pressure, such as with air or water, in a manner known in the art to form a system of internal tubular passageways 30 corresponding to the pattern of weld-inhibiting material, as shown in Figure 5. Internal passageways 30 extend internally within panel 10 and are disposed between spaced apart portions of the thickness of said panel. Thus, panel 10 comprises a hollow sheet metal panel or plate having a system of internal fluid passageways 30 for a heat exchange medium extending internally therei.n. If the passageways are inflated by the introducti.on of fluid distending pressure between flat die platens, the resultant passageways have a flat topped configuration 31 as shown in Figure 6. If, on the other hand, passageways 30 are formed without the presence of superimposed platens, the resultant passageway configuration has a semicircular shape 32 as shown in Figure 7.
~07~6~
As shown in Figure 5, internal passageways 30 in-clude opposed internal headers 33 connected by internal connect~
ing portions 34 of said passageways extending substantially longitudinally in panel 10 between headers 33 and inter-connecting same, with the opposed headers 33 extending in a direction substantially transverse to said longitudinal passage-ways. Preferab~y, opposed internal headers 33 are connected by a plurality of spaced, parallel individual internal connect-ing portions 34 of said passageways extending between the headers~ Also passageways 30 include entry and exit portions 35 and 36, respectively, extending from internal headers 33 to provide ingress and egress openings for the heat exchange medium.
In accordance with the present invention, the system depicted in Figure 1 is shown in greater detail in the per-spective view of Figure 8 to comprise an inlet manifold or heade,r structure which connects at a plurality of locations along its length to a connecting portion comprisiny a panel possessing a configuration similar to that of panel ~0 illus~
trated in Figure 5. System 37, shown here installed on the roof of a building structure, comprises an inlet header s-truc-ture 38 which connects at a plurality of locations to panels 39 and 39' which serve as the connecting portions of the system. Panel 39 is provided with at least one constriction in internal diameter residing along at least a portion of the passageways comprising panel 39, and, as illus-trated herein, as two such constrictions, one of which comprises constriction 41 located along entry portion 40, and the other of which com-prises constriction 42 located along internal connecting portion 43. Both constrictions 41 and ~2 serve in the same generic capacity, as both assist in reducing pressure drop by L6~9~
regulating the distribution of fluid between the various connecting portions in the system. ~hus, constriction 41 assists in the regulation of fluid distribution between the various pan01s which may comprise the connecting portions within system 37, while constriction 42 provides a similar regularion of fluid flow between the several internal con-necting portions 43 contained within panel 39.
In both instances, the respective constrictions are pictured in closest proximity to the area of greatest turbulence and fluid flow as it has been found that the provision of the constriction at this point serves to divert fluid away from the connecting portion receiving the primary amount of flow, to laterally displaced connecting portions which would ordinarily receive a lesser amount of such flow. Thus, in Figure 8, constriction 41 is located in the entry portion of panel 3g closest to the origin of fluid flow in manifold or header structure 38, since turbulence decreases as the fluid passes through header structure 38 to laterally displaced panel 39'. Correspondingly, the provision of constric-tion 42 adjacent entry portion 40 serves to divert fluid away from the central-most connecting portion 43 to laterally displaced connecting portions~ Though constrictions 41 and 42 are illustrated as singular structures in Figure 8, and in the several ~igures in which such constrictions are shown, it is to be understood that a plurality of such constrictions could be employed in a variety of locations to provide precise control over fluid flow among the various connecting portions in the system, including the internal connecting portions pro-vided in the respective panels when employed therein As noted above, the theory of operation of the con-striction in the system of the present invention is tha-t the ~07464gl creation of a minor pressure drop within those connector portion or portions which tend to experience the greatest volume and rate of fluid flow will compensate for and thereby reduce or totally eliminate the pressure drop experienced by those connector portions which are laterally displaced from the area of greatest turbulence and fluid flow. Specifically, fluid entering entry portions 40 and 40' must travel a greater distance to reach exit portions 44 and 44' as depicted at the lowermost ends of panels 39 and 39', as it is required to move laterally to outermost internal connecting portions 43 and 43' in its travel, Similarly, a greater distance of travel through the system is involved when fluid is diverted to panel 39' from panel 39~ This greater distance promotes the increased pressure drop through the outermost connector portion, which the present invention proposes to alleviate.
As noted briefly earlier, constrictions 41 and 42 are merely representative in their illustration in Figure 8, as variations in internal diameter, length, and location on or within a particular connecting portion may be varied to suit the flow conditions attending the particular application in which the system may be employed. Thus, constrictions 41 and 42 may be located at the opposite end of panel 39 or may extend the entire length of the structures in which they are located~ Likewise, as noted earlier, the exact internal diameter of the constrictions may vary depending upon both the ultima-te application and the design of the system in which they are to be employed.
Panels which may be employed in the present invention may assume a wide variety of configurations while embodying the feature of at least one constr.iction in internal diameter located within at least one of the internal connecting portions - - \
1~7~69L~
of said passageways, Specifically, referring to Figure 9, panel 45 is depicted which generally resembles panel 10 in its gross configuration. Panel 45 is modified by the provision of internal headers 46 which are inclined with respect to the direction of fluid flow, corresponding in this instance, to the longitudinal dimension of the panel. Specifically, headers 46 are inclined at an angle of at least 91, and preferably 92 to 100 with respect to longitudinal edge 47 of panel 45.
The aforementioned angle, labeled ~, is actually measured in relation to entry portion 48 and exit portion 49, respectively.
This configuration has been found to enhance fluid flow and exit drainage through the passageways of the panel, thereby preventing air locks and sediment collection due to fluid stagnation, In addition to the provision of headers 46 at the aforementioned angle ~, panel 45 possesses the additional feature of the provision within headers 46 of a plurality of bonded portions 50 of the metal which are welded together and provide increased header strength, improved fluid flow control and directionality and interruption in the flow of heat ex-change fluid, Bonded portions 50 are easily provided by the omission of weld preventive material at the designated places within the header pattern.
Referring further to Figure g, panel 45 likewise is provided with a plurality of internal connecting portions 51 extending between headers 46, wherein the central~most connect ing portion, likewise most adjacent entry portion 48 is provided with a constriction 52 in its internal diameter to further enhance fluid distribution. It can thus be seen that the design of the panel of Figure 9 integrates the features of the angled headers 46, bonded portions 50 and constriction 52 to ~ 7~6~
-improve fluid flow and heat exchange efficiency.
As can be seen from the figures, the panels of Figures 5, 8, 9 and ll are designed whereby the entry and exit portions intersect their respective internal headers at the center thereof and are in line with each other. This symmetri-cal design renders the panels easier to handle and install, as the panels may be placed so that either end thereof may serve as the entry or upper portion. In this connection, as noted earlier, the location of the constriction in the internal connecting portion or portions is not critical, as the panel may clearly be employed in a wide variety of positions. The provision of the constriction results in improved fluid distri-bution regardless of its location along the connecting portion.
The present invention may also be advantageously employed in panels where the entry and exit portions intersect their respective internal headers at opposite ends thereof, as illustrated herein in Figures 10 and 12. In such an instance, the constriction in the connecting portion is preferably located adjacent the entry portion and/or an area where, by virtue of the design of the panel, the preponderance of turbulence and fluid flow will appear to reside, Turning to Figure lO, panel 53 comprises such a design where internal headers 54 are pro-vided in opposed relationship to each other and are so confi-gured that entry portion 55 and exit portion 56 extend from opposite sides of their respective headers. A further feature of panel 53 resides in the configuration of headers 54 wherein the headers are provided in an essentially triangular shape which is partially defined by boundary sides 57 which define a part of the outer perimeter of the panel pattern, as well as two of the three borders of the header s-tructure.
~07~6~5~
Boundary sides 57 are continuous with entry portion 55 and exit portion 56, whereby the longitudinal dimension of at least one of respective sides 57 resides in substantially the same plane as that containing the longitudinal dimension of the respective portions. In the illustration of Figure 10, the respective longitudinal dimensions of sides 57 and the entry and exit portions lie in the same longitudinal plane.
The advantage conferred by this arrangement is that the greatest depth or capacity of internal header 54 is placed closest to the area of greatest turbulénce and flow, that being the locus of entry and exit or heat exchange 1uid. Thus, for example, fluid entering entry portion 55 encounters the greatest depth of header 54 as defined by vertically extending side 57.
As panel 53 is generally employed in the upright position wherein the top edge comprises the location of entry portion 55, the primary direction of flow is naturally dictatedby gravity to be vertically downward by the most direct route. Thus, fluid entering at portion 55 tends to travel directly down through vertically adjacent internal connecting portions 58, and, as said connecting portions become filled, tends to spill over to laterally displaced parallel connecting portions.
Referring further to Figure 10, connecting portions 58 are provided with a constriction 59 located in the internal connecting portion 58 most adjacent entry portion 55 whereby the connecting portion 58 vertically adjacen-t entry portion 55 is provided with a pressure drop serving to distribute fluid in the direction of the internal connecting portions which are laterally displaced from said entry portion. Again, though only one constriction 59 is illustrated, it is intended that the size and number of such constrictions can be varied to achieve the desired distribution~ Thus, in the panel of -` ~6)7~
Figure 10, as well as in all other panels illustrated herein, a sexies of constrictions can be provided which define a gradient of internal diameters specifically devised to esta-blish uniform flow throughout the various connecting portions.
A further feature of the particular panel illus-trated in Figure 10 is the provision of bonded portions-60 which are elongated in shape and which are aligned to define parallel-directed fluid channels 61 integral with said internal connecting portions and running substantially transverse thereto, which serve to assist in the lateral displacement of heat exchange fluid to respective internal connecting portions 58. Though illustrated as oblong or substantially rectangular in shape, bonded portions 60 may assume a wide variety of shapes to provide the parallel channels 61 desired and employed herein.
A further embodiment of the present invention is illustrated in Figure 11 wherein panel 62, comprising opposed internal headers 63 connected by internal connecting portions 64 extending therebetween, and entry portion 65 and exit portion 66 extending from the opposite sides thereof, is pro-vided with a fluid distribution pattern within headers 63 com-prising bonded portion 67. Though the description and accom-panying illustration refer to a single bonded portion, it is to be understood that the invention is not limited thereby, as patterns are contemplated which, for example, may comprise a plurality of bonded portions and headers of various con-figurations. Bonded portion 67 defines at least one point along its perimeter comprising a wedge-shaped projection 68 which assists in the distribution of flow of the heat exchange medium. Projections 68 are respectively located adjacent and in juxtaposition to entry portion 65 and exit portion 66 in 1074~j4~
Figure 11 as an illustration of one of the features of the invention. The positioning of a projection 68 particularly with respect to entry portion 65 facilitates the proportionate division of the incoming stream of fluid into two discrete fluid channels. Further, the provision of bonded portion 67 serves to maintain each channel under a uniform pressure which assists in overcoming the aforenoted problem of pressure drop.
Fluid thus leaving the area of internal header 63 is permitted to flow evenly and rapidly into respective internal connecting portions 64. Likewise, the provision of bonded portion 67 near exit portion 66 likewise assists in preventing the develop-ment of pressure drop as the fluid medium reaches the opposite end of panel 62.
~ Panel 62 is provided with a pair of constrictions 69 located at the lateral-most connecting portions 64 adjacent header 63 associated with entry portion 65. As bonded portions 67 effectively divide the entry fluid into two streams within internal header 63, the provision of constrictions 69 adjacent the lateral ends of header 63 and bonded portion 67 places the constriction in the position most nearly adjacent entry por-tion 65. Thus, the inducement of a slight pressure drop in the lateral-most internal connecting portions assists in diverting fluid to the central-most connecting portions which, in panel 62, are furthest displaced ~rom entry portion 65.
It is thus seen that the provision of constrictions 69 in conjunction with bonded portions 67 serves to assure a uni-formity of fluid flow within panel 62 that effectively prevents the occurrence of pressure drop within the panel~
Referring now to Figure 12, a further embodiment of the present invention is illustrated wherein panel 70 employs internal headers 71 which are disposed at an angle labeled 7~64~
corresponding to an angle ranging from 91 to 100, as dis-closed with respect to angle ~ in Figure 9. In addition, panel 70 possesses internal passageways 72 which are like-wise^ d~sposed at an angle labeled ~ with respect to the longi-tudinal dimension of the panel as defined by a longitudinal edge thereof, extended in phantom and labeled 73. This angle is at least 1 with respect to longitudinal edge 73, gener-ally ranges from 2 to 10, and preferably is from 2-1/2 to 7-1~2. The provision of angle ~ in conjunction with angle ~
establishes corresponding inclines in both the internal headers 71 and the internal connecting portions 72 which enables panel 70 to provide efficient drainage regardless of the plane in which the panel is mounted, Thus, it can be visualized that the panel may be rotated 90 whereby entry portion 74 and exit portion 75 are relocated to the respective entry portion 74' and exit portion 75' shown in phantom. Thus, panel 70 confers a greater versatility of location as it can be mounted in either a horizontally extended or a vertically extended posi-tion while maintaining a desirable level of fluid flow and drainage. Naturally, bonded portions 76 situated in headers 71 confer increased header strength, improved fluid flow and directionality.
As with the previous panels discussed, panel 70 is provided,within the connecting portions 72 most adjacent entry portion 74, with a constriction 77 which further assists in the distribution of fluid to connecting portions 72 conven-tionally experiencing the greatest pressure drop. Though con-striction 77 is illustrated as a single such constriction located on the connecting portion 72 most adjacent entry portion 74, it is to be understood that the dynamics of panel - ~)746~
70 may in fact dictate that constrictions 77 be placed else-where, as perhaps fluid flow may concentrate primarily in the connecting portion most laterally displaced from entry portion 74. Such modifications are considered within the scope of the invention as defined and ~xpressed herein.
As noted earlier, the foregoing discussion and illustration has dealt with the provision of at least one constriction extending along at least a portion of at least one connecting portion within a heat exchange system and/or panel as defined earlier. It is therefore contemplated that a plurality of such constrictions may be provided in several or all of the connecting portions present in a given panel of such size that an accurate metering of fluid can be achievèd to totally eliminate pressure drop therefrom. Thus, referring now to Figure 13, panel 80 similar in basic design to that of panel 10 of Figure 5, is illustrated with internal connecting portions 81 each provided with a constriction 82. From the figure, it is apparent that the constriction provided on the connecting portion most adjacent entry portion 83 effects the greatest reduction in internal diameter. The constrictions 82 provided on internal connecting portions 81 ir~lediately laterally adjacent central connecting por-tion 81 are equal in internal diameter and are slightly larger than that of the central-most constriction. I,ikewise, the lateral-most con-strictions are of an equal diameter that is greater in size than that of the next adjacent constrictions. This apparent gradation in the internal diameter of constrictions 82 serves to provide a close control over the amount of fluid flow that each connecting portion will entertain.
As noted earlier, further variations in the present invention would include the extension of the constrictions in 46~9 length from the portions illustrated in the figures to the full length of the entry or exit portions in the case of the system, or the internal connecting portions in the individual panel. Also, though the panel of Figure 12 suygests that a uniform gradation of constriction sizes may be employed, this size differential may be instituted at random to achieve parti-cular flow effects in given stiuations requiring same.
The internal connecting portions provided in the panels prepared in accordance with the present invention may, in a preferred embodiment comprise a plurality of spaced parallel individual passageways extending between the respec-tive headersO This preferred configuration is illustrated in the accompanying figures, however the invention is not limited thereto, as connecting portions displaced at slight angles with respect to each other might be employed.
It can be seen that the present invention contemplates a wide variety of heat exchange systems, extending from those employing a single collector panel in the path of fluid cir-culation to installations of a multiplicity of panels or other fluid connections, where the path of flow and thus the exposure to heat exchange can vary greatly within the system itself.
In all instances, the concepts of the present invention are clearly pertinent and useful.
Naturally, further alternative designs may be envisioned by one skilled in the art in accordance with the concepts described above.
It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modification of form, size, arrangement of parts and details ~74691~
of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined by the claims.
The present invention relates to heat exchange systems compris~ng a plurality of internal tubular passageways disposed in a spaced apart relation to each other, which possess utillty in heat exchange applications wherein a heat exchange medium is circulated through the passageways.
A partlcular application of such a system resides in devices u~ilizing solar energy, and specifically~ solar energy absorbing devices for elevatlng fluid temperature.
It is well known that the radiatlon of the sun can be collected as a source o~ energy L or heatin~ or cooling or for direct conversion to electricity. Heating and cooling depend upon collection of rays of solar energy in a fluid heating transfer system. The heated fluid is pumped or allowed to flow to a place of utilization for the thermal energy it has acquired.
In certain areas of the world, solar energy is the most abundant ~orm of available energy if it could be har-nessed economically. Even in more developed areas of the world, the economic harnessing of solar energy would provide an att~active alternative to the use of fossile fuels for energy generation.
One of the problems attending the development of an efficient system for the conversion of solar energy resides with the structure and design of the solar energy absorbing device, or solar collector. This solar collector generally comprises a rectangular plate-like structure possessing channels or passageways for the circulation of the energy absorbing fluid medium. Conventionally, these panels have comprised a pair of opposed expanded passageways, known as ~07~4~
headers, which are placed at oppostte ends o~ the panel, and are connected by a plurality of tubular passageways which are often in parallel relation with respect to each other.
These passageways, as well as the headers themselves, have generall~ been disposed at right angles with respect to each other and in parallel relation with respect to the horizontal and vertical dimensions, respectively, o~ the panel.
Difficulty encountered with known solar collectors re-lates to the uniformity of distribution of the heat exchange fluid through the several connectir.g tubular passageways lying between the headers. Though fluid would ideall~J
pass through the individual connector tubes unlformly with respect to velocity, small variations in tube width, tube height and particular travel distar.ce from header to header cause variations in flow rate due to pressure drop through the ~ndividual connector tubes. Such variations a~ect the ~low rate and the heat collection rate of the connector tubes and the panel as a whole.
The above problem becomes particularly acute in the instance where collector systems comprlsing a plurality o~ panels~ which may be placed in either parallel or serial relation to each other are employed. In such systems, . .
tne pressure drop experienced within the individual panels is compounded b~y the pressure drop and unequal flcw occurring between the panels as fluid ~lows from the central manifold or header structure.
SU~ARY OF THE INVENTION
In accordance with the present invention, a heat ex-~07~649 changer is provided which possesses signi~icantly improved efficiency, and specific utility in solar energy applica tions.
The present invention comprises a system o~
tubular passageways for a heat exchange medium defining opposed header structures connected by connecting portlsns of said passageways extending therebetween, said connecting portions having entry and exit portions communicating wi~h said headers to provide ingress and egress openings for said heat exchange medium, wherein said connecting portions are pro~ided with at least one constriction in internal diameter extending along at least a portion of the length of at least one CL said connecting portions to assist in t~e dis-trlbution cf flow o~ said heat e~change medium.
The system of the present invention may comprise a central inlet manifold or header structure which connects at one or more points to a plurality of connecting portions which may, in one embodiment, comprise individual heat exchange panels. The individual panels may define a wide variety of patterns of passageways including one or more entry or exit portions, wherein at least one constriction is p-r~vided a}ong a portion of at least one of said entry or exlt portlons.
In a partlcular embodimentj the present invention may comprise a system of internal tubular passageways for a heat exchange medlum, said internal passage-h2ys contained within an indlvidual panel and disposed between spaced apart portions of the thickness of the panel to define opposed ln.~ern21 headers connected by internal connecting portions of said passageways extending therebetween. The 6~L~
lnternal passageways are provided with entry and exit portlons extending from the headers to opposed edges of the panel in order ko provide ingress and egress openlngs for the heat exchange medium. The internal connecting portions are modified by the provision of at least one constriction in internal diameter located on at least a portlon of the length of at least one of said connecting portions which assists in maintaining uniform flow of heat exchange fluld through said connecting portions.
The system of the present invention exhibits improved fluid flow and heat exchar.ge efficiency by the allocation of flow through the connecting portions achieved with the constrictions provided therein. The size, number and location of said constrictions may vary accord~ng to the size, disposition and number of the connecting portions employed.
As indicated above, the preferred embodiment of the present invention utilizes, as at least a part thereof, a metal panel having a system o~ internal fluid passageways, conventionally painted blackg as will be described in more detall here~nbelow. The concepts of the present invention may, however, also be advantageously utilized in heat exchangers generally, such as, for example, using extrusions.
Since the concepts of the present invention are particularly advantageous in metal panels having a system of internal fluid passageways, the present invention will be specifically described hereinbelow utilizing this type of system.
Accordingly, it is a principal ob~ect of the present invention to provide a heat exchange system which enables the efficient and economical transfer of heat energy.
~10i74~4~
It is a further object of the present invention to provide a system as aforesaid which is particularly suited for use in solar energy collection.
It is yet a further object of the present invention to provide a system as aforesaid which is contained within a single metal panel and is efficiently designed to allow maximum utilization of internal passag~way systems for solar energy collection.
In accordance with a specific embodiment, a heat exchange system for use in a solar energy collector system comprises a plurality of passageways for a heat exchange medium dafining opposed header structures connected by a plurality of spaced, parallel individuai connecting portions of said passage-ways extending therebetween, said passageways having entry and exit portions extending from said header structures to provide ingress and egress openings for said heat exchange medium, wherein ~aid connecting portions are provided with a plurality of con~trictions in internal diameter extending along at least a portion of the length thereof wherein at least one of said constrictions ha~ differing internal diame~er ~o that the con-striction adjacent the area of greatest turbulence and fluid flow has the smallest internal diameter over at least a portion of its length and the constrictions on individual connecting portions have gradually increasing internal diameter .in relation to increased distance from said area of greatest turbulence, said constrictions serving to divert fluid away from the connect-ing portion receiving the primary amount of flow and to regulate the rate of flow of said heat exchange medium between all of said connecting portions.
In accordance with a further embodiment, there is provided, in a solar energy collector system including at least 46~9 one heat exchange panel possessing a syotem of internal tubular passageways defining opposed h~aders connec~d by a plurality of spaced, parallel individual connecting portions of said passageways extending therebetween, said passageways including entry and exit portions extending from opposite ends of said headers to provide ingress and egress openings for a heat exchange medium, the improvement which comprises providing said connecting portions with a plurality of constrictions in internal diameter extending along at least a portion of the length thereof wherein at least some o~ said constrictions have differing internal diameter so that the constriction adjacent said entry portion has the smallest internal diameter over at least a portion of its length and the constrictions on individual connecting portions have gradually increasing internal diameter in relation to increased distance from said entry portion, said constrictions serving to divert fluid away from the connecting portion adjacent said entry portion to regulate the rate of flow of said heat exchange medium between said connecting portions.
In accordance with a still further embodiment, a metal panel for use in a solar energy collector system has a desired system of internal tubular passageways for a heat exchange medium disposed between spaced apart portions of the thickness of said panel and defining opposed internal headers connected by a plurality of spaced, parallel individual internal connecting portions o~ said passageways extending therebetween, said internal passageways having entry and exit portions extend-ing from said internal h~aders to opposed edges of said panel to provide ingress and egress openings for said heat exchange medium, w~erein said connecting portions are provided with a plurality of constrictions in intçrnal diameter extending along ,.,. ;~
5a ~
.!
~74~
at least a portion of the length thereof wherein at least some of said constrictions have differing internal diameter so that the constriction adjacent said ~ntry portion has the smallest internal diameter over at least a portion of its length and the constrictions on individual connecting portions have gradu-ally increasing internal diameter in relation to increased distance from said entry portion, said constrictions serving to divert fluid away from the connecting portion adjacent said entry portion to regulate the rate of flow of said heat exchange medium between all of said connecting portions.
Further objects and advantages will become apparent to those skilled in the art as a detailed description proceeds with reference to the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagram schematically depicting a heat exchange system representative of the present invention.
Figure 2 is a perspective view of a sheet of metal having a pattern of weld-inhibiting material applied to a surface thereof.
Figure 3 is a perspective view of a composite metal blank wherein a second sheet of metal is superimposed on the sheet of metal shown in Figure 2 with khe pattern of weld-inhibiting material sandwiched therebetween.
Figure 4 is a schematic perspective view showing the sheets of Figure 3 being welded together while passing through a pair of mill rolls.
Figure 5 is a top view showing a panel useful in the present invention having internal tubular passageways disposed batween ~paced apart portions of the thickness of the panel in the areas of the weld-inhibiting material.
Figure 6 is a sectional view taken along lines 6-6 of Figure 5.
- 5b -~7469~
Figure 7 is an alternate view showing a variation in the tube configuration similar to the view of Figure 6.
Figure 8 is a blown-up perspective view showing the system of Figure l in greater detail utilizing as connecting portions the panel of Figure 5.
Figures 9-13 are top views showing alternate embodi-ments of the invention illustrated in Figure 5.
DETAILED DESCRIPTION
In accordance with the present invention, the fore-going objects and advantages are readily attained.
The system of the present invention is provided with a flow regulating mechanism in the form of at least one con-striction provided in at least one connecting portion extend-ing at least a portion of the length of said connecting portion which serves to regulate the flow of heat exchange medium between the connecting portions extending from and between the opposed header structures or manifolds.
The present invention deals with the problem of non-uniform flow resulting from excessive pressure drop occurring under the turbulent operating conditions to which the heat exchange systems are su~jected. Specifically, the systems are conventionally installed in the vertical plane whereby the inlet opening is located above the connecting portions. Fluid flows at a rate accelerated by gravity from the header into the entry portions, where it is then split into a plurality of channels defined by the remainder of the connecting portions to follow through the system. As noted earlier, nonuniform flow often results from irregularities in the size and shape of the connecting portions because of the pressure drop which develops therein. This pressure drop, in certain instances, causes air pockets to develop which impede the movement of ,. ... .
~L~)7~64~
heat exchange fluid. To this end, the provision of controlled restriction in the internal diameter of the connecting por-tions by the employment of the present invention serves to efficiently distribute fluid flow and prevent the development of the detrimental pressure differential.
The present invention is preferably utilized as a solar heating system as shown in Figure 1, and in greater detail in Figure 8, wherein a plurality of panels of the present invention 10 are mounted on roof 11 of building 12 with conduits 13 and 14 connected in any convenient fashion to the equipment in the building, with the connections no-t shown. Thus, for example, cold water may go into conduit 13 from the building 12 by means of a conventional pump or the like. The water flows from conduit 13 to common manifold or header structure 13a and is distributed into a plurality of parallel-directed connecting portions of said system comprisin~ in the illus-tration panels 10. The water flows through panels 10, is heated by means of solar energy, is collected in common mani-fold or header structure 14a and flows into conduit 14. The heated water is then stored or utilized in a heat exchange system inside the building in a known manner Naturally, if desired, the water flow may be reversed with the cold water entering via conduit 14 and collected via conduit 13. Al-ter-natively, the solar heating unit of the present invention may be used or placed in any suitable environment, such as on the ground with suitable fasteners -to prevent displacement by wind or gravity.
The solar heating unit of the present invention may be used for residential heating purposes, such as in providing hot water in a residential environment. For example, three of the illustrated panels having dimensions of 8 feet x 4 feet .. . ~, -- ~0~46i~L~
would efficiently supply an average household of four with hot water for home use. Alternatively, the system of the present invention may be conveniently used for heating water for swim-ming pools or for preheating water for domestic gas or oil fired domestic hot water heaters. The fluid is preferably retained in a closed systern with the water in the system heated in the solar unit and delivered into an insulated cistern or container so that the heated fluid may be stored up during sun-shine for use on cool cloudy days or at night when the heating of the fluid in the panel will not be of sufficient degree to provide the desired heat at the point of use.
A thermostat not shown is desirably installed at the top of the solar heater and this thermostat may be set to turn on a circulating pump whenever the temperature reaches a pre-determined reading. The pump will then pump the water through the system as generally outlined above.
As indicated above, the present invention may employ as the energy collector structure, one or more connecting por-tions comprising a metal panel of a particularly preferred design and construction for optimum efficiency in the solar heating system as described above. The metal panel is desir-ably fabricated by the ROLL-BOND~ process as shown in U. S.
Patent 2,690,002. Figure 2 illustrates a single sheet of metal 20 as aluminum or copper or alloys thereof, having applied to a clean surface 21 thereof a pattern of weld-inhibiting material 22 corresponding to the ultimate desired passageway system. Figure 3 shows the sheet 20 having super-imposed thereon a second sheet 23 with a pattern of weld-inhibiting material 22 sandwiched between the units, The units 20 and 23 are tacked together as by support welds 24 to prevent relative movernent between the sheets as they are ~ ~L079L6~19 subsequently welded together as shown in Figure a by passing through a pair of mill rolls 25 to form weld0d blank 26. It is normally necessary that the sheets 20 and 23 be heated prior to passing through the mill rolls to assure that they weld to each other in keeping with techniques well known in the rolling art.
The resultant blank 26 is characterized by the sheets 20 and 23 being welded together except at the area of the weld-inhibiting material 22 The blank 26 with the unjoined inner portion corresponding to the pattern of weld-inhibiting material 22 may then be softened in any appropriate manner as by anneal-ing, and thereafter the blank may be cold rolled to provide a more even thickness and again annealed. The portions of the panel adjacent the weld-inhibiting material 22 are then in-flated by the introduction of fluid distending pressure, such as with air or water, in a manner known in the art to form a system of internal tubular passageways 30 corresponding to the pattern of weld-inhibiting material, as shown in Figure 5. Internal passageways 30 extend internally within panel 10 and are disposed between spaced apart portions of the thickness of said panel. Thus, panel 10 comprises a hollow sheet metal panel or plate having a system of internal fluid passageways 30 for a heat exchange medium extending internally therei.n. If the passageways are inflated by the introducti.on of fluid distending pressure between flat die platens, the resultant passageways have a flat topped configuration 31 as shown in Figure 6. If, on the other hand, passageways 30 are formed without the presence of superimposed platens, the resultant passageway configuration has a semicircular shape 32 as shown in Figure 7.
~07~6~
As shown in Figure 5, internal passageways 30 in-clude opposed internal headers 33 connected by internal connect~
ing portions 34 of said passageways extending substantially longitudinally in panel 10 between headers 33 and inter-connecting same, with the opposed headers 33 extending in a direction substantially transverse to said longitudinal passage-ways. Preferab~y, opposed internal headers 33 are connected by a plurality of spaced, parallel individual internal connect-ing portions 34 of said passageways extending between the headers~ Also passageways 30 include entry and exit portions 35 and 36, respectively, extending from internal headers 33 to provide ingress and egress openings for the heat exchange medium.
In accordance with the present invention, the system depicted in Figure 1 is shown in greater detail in the per-spective view of Figure 8 to comprise an inlet manifold or heade,r structure which connects at a plurality of locations along its length to a connecting portion comprisiny a panel possessing a configuration similar to that of panel ~0 illus~
trated in Figure 5. System 37, shown here installed on the roof of a building structure, comprises an inlet header s-truc-ture 38 which connects at a plurality of locations to panels 39 and 39' which serve as the connecting portions of the system. Panel 39 is provided with at least one constriction in internal diameter residing along at least a portion of the passageways comprising panel 39, and, as illus-trated herein, as two such constrictions, one of which comprises constriction 41 located along entry portion 40, and the other of which com-prises constriction 42 located along internal connecting portion 43. Both constrictions 41 and ~2 serve in the same generic capacity, as both assist in reducing pressure drop by L6~9~
regulating the distribution of fluid between the various connecting portions in the system. ~hus, constriction 41 assists in the regulation of fluid distribution between the various pan01s which may comprise the connecting portions within system 37, while constriction 42 provides a similar regularion of fluid flow between the several internal con-necting portions 43 contained within panel 39.
In both instances, the respective constrictions are pictured in closest proximity to the area of greatest turbulence and fluid flow as it has been found that the provision of the constriction at this point serves to divert fluid away from the connecting portion receiving the primary amount of flow, to laterally displaced connecting portions which would ordinarily receive a lesser amount of such flow. Thus, in Figure 8, constriction 41 is located in the entry portion of panel 3g closest to the origin of fluid flow in manifold or header structure 38, since turbulence decreases as the fluid passes through header structure 38 to laterally displaced panel 39'. Correspondingly, the provision of constric-tion 42 adjacent entry portion 40 serves to divert fluid away from the central-most connecting portion 43 to laterally displaced connecting portions~ Though constrictions 41 and 42 are illustrated as singular structures in Figure 8, and in the several ~igures in which such constrictions are shown, it is to be understood that a plurality of such constrictions could be employed in a variety of locations to provide precise control over fluid flow among the various connecting portions in the system, including the internal connecting portions pro-vided in the respective panels when employed therein As noted above, the theory of operation of the con-striction in the system of the present invention is tha-t the ~07464gl creation of a minor pressure drop within those connector portion or portions which tend to experience the greatest volume and rate of fluid flow will compensate for and thereby reduce or totally eliminate the pressure drop experienced by those connector portions which are laterally displaced from the area of greatest turbulence and fluid flow. Specifically, fluid entering entry portions 40 and 40' must travel a greater distance to reach exit portions 44 and 44' as depicted at the lowermost ends of panels 39 and 39', as it is required to move laterally to outermost internal connecting portions 43 and 43' in its travel, Similarly, a greater distance of travel through the system is involved when fluid is diverted to panel 39' from panel 39~ This greater distance promotes the increased pressure drop through the outermost connector portion, which the present invention proposes to alleviate.
As noted briefly earlier, constrictions 41 and 42 are merely representative in their illustration in Figure 8, as variations in internal diameter, length, and location on or within a particular connecting portion may be varied to suit the flow conditions attending the particular application in which the system may be employed. Thus, constrictions 41 and 42 may be located at the opposite end of panel 39 or may extend the entire length of the structures in which they are located~ Likewise, as noted earlier, the exact internal diameter of the constrictions may vary depending upon both the ultima-te application and the design of the system in which they are to be employed.
Panels which may be employed in the present invention may assume a wide variety of configurations while embodying the feature of at least one constr.iction in internal diameter located within at least one of the internal connecting portions - - \
1~7~69L~
of said passageways, Specifically, referring to Figure 9, panel 45 is depicted which generally resembles panel 10 in its gross configuration. Panel 45 is modified by the provision of internal headers 46 which are inclined with respect to the direction of fluid flow, corresponding in this instance, to the longitudinal dimension of the panel. Specifically, headers 46 are inclined at an angle of at least 91, and preferably 92 to 100 with respect to longitudinal edge 47 of panel 45.
The aforementioned angle, labeled ~, is actually measured in relation to entry portion 48 and exit portion 49, respectively.
This configuration has been found to enhance fluid flow and exit drainage through the passageways of the panel, thereby preventing air locks and sediment collection due to fluid stagnation, In addition to the provision of headers 46 at the aforementioned angle ~, panel 45 possesses the additional feature of the provision within headers 46 of a plurality of bonded portions 50 of the metal which are welded together and provide increased header strength, improved fluid flow control and directionality and interruption in the flow of heat ex-change fluid, Bonded portions 50 are easily provided by the omission of weld preventive material at the designated places within the header pattern.
Referring further to Figure g, panel 45 likewise is provided with a plurality of internal connecting portions 51 extending between headers 46, wherein the central~most connect ing portion, likewise most adjacent entry portion 48 is provided with a constriction 52 in its internal diameter to further enhance fluid distribution. It can thus be seen that the design of the panel of Figure 9 integrates the features of the angled headers 46, bonded portions 50 and constriction 52 to ~ 7~6~
-improve fluid flow and heat exchange efficiency.
As can be seen from the figures, the panels of Figures 5, 8, 9 and ll are designed whereby the entry and exit portions intersect their respective internal headers at the center thereof and are in line with each other. This symmetri-cal design renders the panels easier to handle and install, as the panels may be placed so that either end thereof may serve as the entry or upper portion. In this connection, as noted earlier, the location of the constriction in the internal connecting portion or portions is not critical, as the panel may clearly be employed in a wide variety of positions. The provision of the constriction results in improved fluid distri-bution regardless of its location along the connecting portion.
The present invention may also be advantageously employed in panels where the entry and exit portions intersect their respective internal headers at opposite ends thereof, as illustrated herein in Figures 10 and 12. In such an instance, the constriction in the connecting portion is preferably located adjacent the entry portion and/or an area where, by virtue of the design of the panel, the preponderance of turbulence and fluid flow will appear to reside, Turning to Figure lO, panel 53 comprises such a design where internal headers 54 are pro-vided in opposed relationship to each other and are so confi-gured that entry portion 55 and exit portion 56 extend from opposite sides of their respective headers. A further feature of panel 53 resides in the configuration of headers 54 wherein the headers are provided in an essentially triangular shape which is partially defined by boundary sides 57 which define a part of the outer perimeter of the panel pattern, as well as two of the three borders of the header s-tructure.
~07~6~5~
Boundary sides 57 are continuous with entry portion 55 and exit portion 56, whereby the longitudinal dimension of at least one of respective sides 57 resides in substantially the same plane as that containing the longitudinal dimension of the respective portions. In the illustration of Figure 10, the respective longitudinal dimensions of sides 57 and the entry and exit portions lie in the same longitudinal plane.
The advantage conferred by this arrangement is that the greatest depth or capacity of internal header 54 is placed closest to the area of greatest turbulénce and flow, that being the locus of entry and exit or heat exchange 1uid. Thus, for example, fluid entering entry portion 55 encounters the greatest depth of header 54 as defined by vertically extending side 57.
As panel 53 is generally employed in the upright position wherein the top edge comprises the location of entry portion 55, the primary direction of flow is naturally dictatedby gravity to be vertically downward by the most direct route. Thus, fluid entering at portion 55 tends to travel directly down through vertically adjacent internal connecting portions 58, and, as said connecting portions become filled, tends to spill over to laterally displaced parallel connecting portions.
Referring further to Figure 10, connecting portions 58 are provided with a constriction 59 located in the internal connecting portion 58 most adjacent entry portion 55 whereby the connecting portion 58 vertically adjacen-t entry portion 55 is provided with a pressure drop serving to distribute fluid in the direction of the internal connecting portions which are laterally displaced from said entry portion. Again, though only one constriction 59 is illustrated, it is intended that the size and number of such constrictions can be varied to achieve the desired distribution~ Thus, in the panel of -` ~6)7~
Figure 10, as well as in all other panels illustrated herein, a sexies of constrictions can be provided which define a gradient of internal diameters specifically devised to esta-blish uniform flow throughout the various connecting portions.
A further feature of the particular panel illus-trated in Figure 10 is the provision of bonded portions-60 which are elongated in shape and which are aligned to define parallel-directed fluid channels 61 integral with said internal connecting portions and running substantially transverse thereto, which serve to assist in the lateral displacement of heat exchange fluid to respective internal connecting portions 58. Though illustrated as oblong or substantially rectangular in shape, bonded portions 60 may assume a wide variety of shapes to provide the parallel channels 61 desired and employed herein.
A further embodiment of the present invention is illustrated in Figure 11 wherein panel 62, comprising opposed internal headers 63 connected by internal connecting portions 64 extending therebetween, and entry portion 65 and exit portion 66 extending from the opposite sides thereof, is pro-vided with a fluid distribution pattern within headers 63 com-prising bonded portion 67. Though the description and accom-panying illustration refer to a single bonded portion, it is to be understood that the invention is not limited thereby, as patterns are contemplated which, for example, may comprise a plurality of bonded portions and headers of various con-figurations. Bonded portion 67 defines at least one point along its perimeter comprising a wedge-shaped projection 68 which assists in the distribution of flow of the heat exchange medium. Projections 68 are respectively located adjacent and in juxtaposition to entry portion 65 and exit portion 66 in 1074~j4~
Figure 11 as an illustration of one of the features of the invention. The positioning of a projection 68 particularly with respect to entry portion 65 facilitates the proportionate division of the incoming stream of fluid into two discrete fluid channels. Further, the provision of bonded portion 67 serves to maintain each channel under a uniform pressure which assists in overcoming the aforenoted problem of pressure drop.
Fluid thus leaving the area of internal header 63 is permitted to flow evenly and rapidly into respective internal connecting portions 64. Likewise, the provision of bonded portion 67 near exit portion 66 likewise assists in preventing the develop-ment of pressure drop as the fluid medium reaches the opposite end of panel 62.
~ Panel 62 is provided with a pair of constrictions 69 located at the lateral-most connecting portions 64 adjacent header 63 associated with entry portion 65. As bonded portions 67 effectively divide the entry fluid into two streams within internal header 63, the provision of constrictions 69 adjacent the lateral ends of header 63 and bonded portion 67 places the constriction in the position most nearly adjacent entry por-tion 65. Thus, the inducement of a slight pressure drop in the lateral-most internal connecting portions assists in diverting fluid to the central-most connecting portions which, in panel 62, are furthest displaced ~rom entry portion 65.
It is thus seen that the provision of constrictions 69 in conjunction with bonded portions 67 serves to assure a uni-formity of fluid flow within panel 62 that effectively prevents the occurrence of pressure drop within the panel~
Referring now to Figure 12, a further embodiment of the present invention is illustrated wherein panel 70 employs internal headers 71 which are disposed at an angle labeled 7~64~
corresponding to an angle ranging from 91 to 100, as dis-closed with respect to angle ~ in Figure 9. In addition, panel 70 possesses internal passageways 72 which are like-wise^ d~sposed at an angle labeled ~ with respect to the longi-tudinal dimension of the panel as defined by a longitudinal edge thereof, extended in phantom and labeled 73. This angle is at least 1 with respect to longitudinal edge 73, gener-ally ranges from 2 to 10, and preferably is from 2-1/2 to 7-1~2. The provision of angle ~ in conjunction with angle ~
establishes corresponding inclines in both the internal headers 71 and the internal connecting portions 72 which enables panel 70 to provide efficient drainage regardless of the plane in which the panel is mounted, Thus, it can be visualized that the panel may be rotated 90 whereby entry portion 74 and exit portion 75 are relocated to the respective entry portion 74' and exit portion 75' shown in phantom. Thus, panel 70 confers a greater versatility of location as it can be mounted in either a horizontally extended or a vertically extended posi-tion while maintaining a desirable level of fluid flow and drainage. Naturally, bonded portions 76 situated in headers 71 confer increased header strength, improved fluid flow and directionality.
As with the previous panels discussed, panel 70 is provided,within the connecting portions 72 most adjacent entry portion 74, with a constriction 77 which further assists in the distribution of fluid to connecting portions 72 conven-tionally experiencing the greatest pressure drop. Though con-striction 77 is illustrated as a single such constriction located on the connecting portion 72 most adjacent entry portion 74, it is to be understood that the dynamics of panel - ~)746~
70 may in fact dictate that constrictions 77 be placed else-where, as perhaps fluid flow may concentrate primarily in the connecting portion most laterally displaced from entry portion 74. Such modifications are considered within the scope of the invention as defined and ~xpressed herein.
As noted earlier, the foregoing discussion and illustration has dealt with the provision of at least one constriction extending along at least a portion of at least one connecting portion within a heat exchange system and/or panel as defined earlier. It is therefore contemplated that a plurality of such constrictions may be provided in several or all of the connecting portions present in a given panel of such size that an accurate metering of fluid can be achievèd to totally eliminate pressure drop therefrom. Thus, referring now to Figure 13, panel 80 similar in basic design to that of panel 10 of Figure 5, is illustrated with internal connecting portions 81 each provided with a constriction 82. From the figure, it is apparent that the constriction provided on the connecting portion most adjacent entry portion 83 effects the greatest reduction in internal diameter. The constrictions 82 provided on internal connecting portions 81 ir~lediately laterally adjacent central connecting por-tion 81 are equal in internal diameter and are slightly larger than that of the central-most constriction. I,ikewise, the lateral-most con-strictions are of an equal diameter that is greater in size than that of the next adjacent constrictions. This apparent gradation in the internal diameter of constrictions 82 serves to provide a close control over the amount of fluid flow that each connecting portion will entertain.
As noted earlier, further variations in the present invention would include the extension of the constrictions in 46~9 length from the portions illustrated in the figures to the full length of the entry or exit portions in the case of the system, or the internal connecting portions in the individual panel. Also, though the panel of Figure 12 suygests that a uniform gradation of constriction sizes may be employed, this size differential may be instituted at random to achieve parti-cular flow effects in given stiuations requiring same.
The internal connecting portions provided in the panels prepared in accordance with the present invention may, in a preferred embodiment comprise a plurality of spaced parallel individual passageways extending between the respec-tive headersO This preferred configuration is illustrated in the accompanying figures, however the invention is not limited thereto, as connecting portions displaced at slight angles with respect to each other might be employed.
It can be seen that the present invention contemplates a wide variety of heat exchange systems, extending from those employing a single collector panel in the path of fluid cir-culation to installations of a multiplicity of panels or other fluid connections, where the path of flow and thus the exposure to heat exchange can vary greatly within the system itself.
In all instances, the concepts of the present invention are clearly pertinent and useful.
Naturally, further alternative designs may be envisioned by one skilled in the art in accordance with the concepts described above.
It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modification of form, size, arrangement of parts and details ~74691~
of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined by the claims.
Claims (17)
1. A heat exchange system for use in a solar energy collector system comprising a plurality of passageways for a heat exchange medium defining opposed header structures connected by a plurality of spaced, parallel individual connecting por-tions of said passageways extending therebetween, said passage-ways having entry and exit portions extending from said header structures to provide ingress and egress openings for said heat exchange medium, wherein said connecting portions are provided with a plurality of constrictions in internal diameter extending along at least a portion of the length thereof wherein at least one of said constrictions has differing internal diameter so that the constriction adjacent the area of greatest turbulence and fluid flow has the smallest internal diameter over at least a portion of its length and the constrictions on individual connecting portions have gradually increasing internal diameter in relation to increased distance from said area of greatest turbulence, said constrictions serving to divert fluid away from the connecting portion receiving the primary amount of flow and to regulate the rate of flow of said heat exchange medium between all of said connecting portions.
2. The system of claim 1 wherein at least one of said constrictions is located along at least a portion of said exit portion.
3. The system of claim 1 wherein at least one of said constrictions is located along at least a portion of said entry portion.
4. The system of claim 1 wherein at least one of said connecting portions comprises a metal panel, said panel defining a system of internal tubular passageways for said heat exchange medium.
5. In a solar energy collector system including at least one heat exchange panel possessing a system of internal tubular passageways defining opposed headers connected by a plurality of spaced, parallel individual connecting portions of said passageways extending therebetween, said passageways including entry and exit portions extending from opposite ends of said headers to provide ingress and egress openings for a heat exchange medium, the improvement which comprises providing said connecting portions with a plurality of constrictions in internal diameter extending along at least a portion of the length thereof wherein at least some of said constrictions have differing internal diameter so that the constriction adjacent said entry portion has the smallest internal diameter over at least a portion of its length and the constrictions on indivi-dual connecting portions have gradually increasing internal diameter in relation to increased distance from said entry portion, said constrictions serving to divert fluid,away from the connecting portion adjacent said entry portion to regulate the rate of flow of said heat exchange medium between said connecting portions.
6. A metal panel for use in a solar energy collector system having a desired system of internal tubular passageways for a heat exchange medium disposed between spaced apart portions of the thickness of said panel and defining opposed internal headers connected by a plurality of spaced, parallel individual internal connecting portions of said passageways extending therebetween, said internal passageways having entry and exit portions extending from said internal headers to opposed edges of said panel to provide ingress and egress openings for said heat exchange medium, wherein said connecting portions are provided with a plurality of constrictions in internal dia-meter extending along at least a portion of the length thereof wherein at least some of said constrictions have differing internal diameter so that the constriction adjacent said entry portion has the smallest internal diameter over at least a portion of its length and the constrictions on individual connecting portions have gradually increasing internal diameter in relation to increased distance from said entry portion, said constrictions serving to divert fluid away from the connecting portion adjacent said entry portion to regulate the rate of flow of said heat exchange medium between all of said connect-ing portions.
7. The panel of claim 6 wherein at least one of said constrictions extends substantially the length of said connecting portion.
8. The panel of claim 6 wherein said headers include a fluid distributing pattern comprising at least one bonded portion defining at least one wedge-shaped projection, said projection provided to assist in the distribution of flow of said heat exchange medium.
9. The panel of claim 6 wherein the header and entry portion extending therefrom are located above the connecting portions.
10. The panel of claim 6 wherein at least one of said constrictions is located on the connecting portion most adjacent said entry portion.
11. The panel of claim 10 wherein said entry and exit portions are centrally displaced along said header and at least one of said constrictions is located on the central-most connecting portion.
12. The panel of claim 6 wherein said headers define an angle of at least 91° with respect to the direction of flow of said heat exchange medium in said panel.
13. The panel of claim 12 wherein said headers define an angle of from 92° to 100° with respect to the direction of flow of said heat exchange medium.
14. The panel of claim 6 wherein said entry portion and said exit portion extend from the opposite sides of respective opposed headers.
15. The panel of claim 14 wherein said headers are tri-angular in shape and possess a plurality of parallel fluid channels communicating with said connecting portions and running in a direction substantially transverse thereto.
16. The panel of claim 6 wherein said connecting portions define an angle of at least 1° with respect to a longitudinal edge of said panel.
17. The panel of claim 16 wherein said connecting portions define an angle of from 2 to 10° with respect to said longitudi-nal edge of said panel.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US69520376A | 1976-06-15 | 1976-06-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1074649A true CA1074649A (en) | 1980-04-01 |
Family
ID=24792057
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA279,059A Expired CA1074649A (en) | 1976-06-15 | 1977-05-24 | Heat exchanger exhibiting improved fluid distribution |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1074649A (en) |
-
1977
- 1977-05-24 CA CA279,059A patent/CA1074649A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |