CA1097168A - Solar absorber plate design - Google Patents
Solar absorber plate designInfo
- Publication number
- CA1097168A CA1097168A CA301,058A CA301058A CA1097168A CA 1097168 A CA1097168 A CA 1097168A CA 301058 A CA301058 A CA 301058A CA 1097168 A CA1097168 A CA 1097168A
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- CA
- Canada
- Prior art keywords
- panel
- headers
- header
- longitudinally
- portions
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
A heat exchange panel possessing a system of internal fluid passageways defining at least two longitudinally extended headers extending, substantially the length of the panel, a connecting header located at one end of the panel in a direction transverse to the longitudinally extended headers and interconnecting same, a plurality of connecting portions of said passageways extending transversely between the respective longitudinally extended headers, and fluid exit and entry portions extending longitudinally from at least two of said headers. The configuration of the headers serves to reduce pressure drop while maintaining uniformity of fluid flow under high velocity, and renders the panel eminently suitable for solar energy applications.
Description
~9716~3 BACKGROUND OF T~E I~VENTIO~
The present invention relates to metal panels having ;~
a system of internal tubular passageways disposed between spaced apart portions of the thickness of the panel. Said panels possess utility in heat exchange applications wherein a heat exchange medium is circulated through said passage-ways A particular application of said panels resides in devices utilizing solar energy, and specifically, solar energy absorbing devices for elevating fluid temperature.
It is well known that the radiation of the sun can ;
be collected as a source of energy for heating or cooling or for direct conversion to electricity. Heating and cooling ~
depend upon collection of rays of solar energy in a fluid ;
heat 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 form of available energy if it could be harnessed economically. Even in more developed areas of the world, the economic harnessing of solar energy would ~ -provide an attractive alternative to the use of fossil 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 .~ - .... , , ~ , .
~9~
headers, which are placed at opposite 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 generally been disposed at right angles with respect to each other and in parallel relation with respect to the horizontal and vertical dimensions, respectively, of the panel.
The aforementioned configuration suffers from certain deficiencies, in that fluid flow tends to encounter pockets of stagnation which cut down on the efficient circulation of solar energy. Further, as a partial result of the turbulent operating conditions attending heat exchange applications, various entrained gases tend to collect in the passageways, with the result that air locks which greatly inhibit flow and reduce the maximum fluid circulation capacity of the panel are often formed. Such difficulties as reduced ~luid velocity, nonuniform flow and excessive pressure drop have been characterized as resulting from the lnefficiencies of such prior art designs. It is, therefore, toward the alleviation of the above difficulties that the present invention is directed.
SUMMARY OF THE INVENTION
In accordance with the present invention, a h~at exchanger is provided which exhibits improved operating efficiency and particular utility in solar energy applications.
In accordance with a specific embodiment of the invention, there is provided a heat exchange panel possessing a system of internal tubular passageways, said tubular passage-ways de~ining at least three generally tapered longitudinally extended headers, at least two of said longitudinally extended headers extending substantially the length of said panel, a connecting header located at one end of said panel transverse to and interconnecting longitudinally extended headers, and
The present invention relates to metal panels having ;~
a system of internal tubular passageways disposed between spaced apart portions of the thickness of the panel. Said panels possess utility in heat exchange applications wherein a heat exchange medium is circulated through said passage-ways A particular application of said panels resides in devices utilizing solar energy, and specifically, solar energy absorbing devices for elevating fluid temperature.
It is well known that the radiation of the sun can ;
be collected as a source of energy for heating or cooling or for direct conversion to electricity. Heating and cooling ~
depend upon collection of rays of solar energy in a fluid ;
heat 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 form of available energy if it could be harnessed economically. Even in more developed areas of the world, the economic harnessing of solar energy would ~ -provide an attractive alternative to the use of fossil 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 .~ - .... , , ~ , .
~9~
headers, which are placed at opposite 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 generally been disposed at right angles with respect to each other and in parallel relation with respect to the horizontal and vertical dimensions, respectively, of the panel.
The aforementioned configuration suffers from certain deficiencies, in that fluid flow tends to encounter pockets of stagnation which cut down on the efficient circulation of solar energy. Further, as a partial result of the turbulent operating conditions attending heat exchange applications, various entrained gases tend to collect in the passageways, with the result that air locks which greatly inhibit flow and reduce the maximum fluid circulation capacity of the panel are often formed. Such difficulties as reduced ~luid velocity, nonuniform flow and excessive pressure drop have been characterized as resulting from the lnefficiencies of such prior art designs. It is, therefore, toward the alleviation of the above difficulties that the present invention is directed.
SUMMARY OF THE INVENTION
In accordance with the present invention, a h~at exchanger is provided which exhibits improved operating efficiency and particular utility in solar energy applications.
In accordance with a specific embodiment of the invention, there is provided a heat exchange panel possessing a system of internal tubular passageways, said tubular passage-ways de~ining at least three generally tapered longitudinally extended headers, at least two of said longitudinally extended headers extending substantially the length of said panel, a connecting header located at one end of said panel transverse to and interconnecting longitudinally extended headers, and
- 2 -generally transversely extended connecting portions of said passageways, said connecting portions extending between longitudinally extendèd headers, at least one fluid entry means longitudinally extending from at least one of said headers and at least one fluid exit means longitudinally extending from another of said headers, wherein said longitudinally extended headers include a centxally located header offset by a pair of laterally displaced headers.
~he panel of the present invention may also comprise a system of tubular passageways for a heat exchange medium defining -2a -:.............. . - .
7~619 at least two longitudinally extended headers extendlng sub-stantially the length of the panel, a connecting header located at one end of the panel interconnecting the longi-tudinally extended headers and lying in a direction trans-verse thereto, generally transversely extending connecting portions of said passageways extending between the respective longitudinally extended headers, and entry and exit portions ext~nding from at least two of said headers to provide ingress and egress openings for the heat exchange medium.
In a preferred embodiment the panel o~ the present ,;
invention comprises at least two longitudinally extended headers of essentially triangular shape,, wherein a single, centrally located inlet header is located between a pair of laterally displaced opposed outlet headers, and said inlet and outlet headers are connected at one end thereof by a transversely extending, substantially rectangularly shaped connecting header, and entry and exit portions are respect-ively provided in extension from said inlet header and said connecting header to provide ingress and egress openings '~
for said heat exchange medium.
The panel of the present invention may possess a wide variation in the configuration of the ~luid distribut-ing pattern to account for variations in size and utility of the particular panel to be prepared. Thus, the panel of the present invention may employ connecting portions disposed at an angle of at least 91 with respect to the longitudinal dimension of the panel to assist in fluid flow. Also, the headers of the present invention may be provided with bonded portions to assist in fluid distribution and to enhance structural stability and resistance to rupture under pressure, 1~9~7~6~
As indicated above, the preferred embodiment of the present invention utilizes a metal panel having a system of internal fluid passageways, conventionally painted blackl as will be described in more detail herein-below. The concepts of the present invention may, howeverl 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 speciically described here- ~;
inbelow utilizing this type of system.
Accordingly, it is a principal object of the present invention to provide a metal panel for use in heat exchange applications which enables the efficient and economical transfer of heat energy.
It is a further object of the present invention to provide a metal panel as aforesaid which is particularly suited for use in a solar energy collector system.
It is yet a further object of the present inven-~O tion to provide a metal panel as aforesaid which is capableof achieving uniform flow at high velocity of a heat exchange medium and a reduction in pressure drop within the passageways of a solar energy collector.
Further objects and advantages will become apparent to those skilled in the art as a detailed des-cription proceeds with reference to the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagram showing schematically the manner in which the panels of the present invention can be ~9'7~6i8 employed.
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 the 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 the panel of the present invention having internal tubular passageways dis-posed between spaced 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.
Figure 7 is an alternate view showing a variation in the tube configuration similar to the view o~ Figure 6, Figures 8, 9, 10 and 11 are top views showing alternate embodiments of the present invention.
DETAILED DESCRIPTIO~
In accordance with the present invention, the ~;
foregoing objects and advantages are readily attained.
The panels of tha present invention ar~ provided with a system of parallel headers connected by fore-shortened connecting por~ions which greatly facilitate flow efficiency and heat exchange.
~L~331'7~61~
As noted earlier, the present invention is directed to the problems of nonuniform flow at reduced velocity, and fluid blockage resulting from the turbulent conditions under which heat exchange panels are operating.
Specifically, the panels are conventionally employed in either the horizontal or the vertical plane whereby fluid entering the panels is under pressure developed by a cir-culating pump or the like, and in the instance of vertical installation, additionally by the force of gravity. The fluid is split within the panel into a plurality of channels through which it passes to effect the heat exchange phenomenon. A problem which has arisen in this arrange-ment results from the turbulence of Eluid movement through the panel which results in a pressure drop between the headers and the connecting portions thereof. This pressure drop causes air pockets to form and tends to impede the movement of fluid. This further results in a reduction in fluid flow and velocity which deleteriously a~fects the efficiency of the panel. The provision of a panel employ-ing a plurality of longitudinally extended headers incombination with connecting passageways of reduced length in accordance with the present invention is believed to cure the aforenoted deficiencies.
The panels of the present invention are prefer-ably utilized in a solar heating system as shown in Figure 1 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 not 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 f~ows along common manifold 13a and is distri-buted into panels 10. me water flows through panels 10, is heated by means of solar energy, is collected in common manifold 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. Alternatively, 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. me solar heating unit of the present invention may be used for residential heating purposes, such as in providing hot water in a residential environ-ment. For example, three panels of the present invention having dimensions of 8 feet x 4 feet would efficiently supply an average household of four with hot water for home use. Alternatively, the solar panels of the present invention may be conveniently used for heating water for swimming pools or for preheating water for domestic gas or oil fired domestic hot water heaters. The fluid is preferably retained in a closed system 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 sunshine 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.
~97~
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 predetermined reading. The pump will then pump the water through the system as generally outlined above, As indicated above, the present invention contem-plates a particularly preferred panel design for optimum efficiency in a solar heating system as described above.
The metal panel or plate of the present invention is desirably fabricated by the ROLL-BO~D~3process 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 superimposed 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 ~o prevent relative movement between the sheets as they are subsequently welded together as shown in Figure 4 by passing through a pair of mill rolls 25 to form welded 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.
m e 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-inhibit-~7~
ing material 22 may then be softened in any appropriatemanner as by annealing, 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 inflated by theintroduction 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. The passageways 30 extend internally within panel 10 and are disposed between spaced apart portior.s of the thickness of said panel. Thus, panel 10 comprises a hollow sheet metal panel or plate having a system of fluid passageways 30 for a heat exchange medium extending internally therein. If the passageways are inflated by the intro,duction 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, t~e resultant passageway configuration has a semicircular shape 32 as shown in Figure 7.
As shown in Figure 5, the passageways 30 include a plurality of headers comprising inlet header 33 and outlet headers 34, all of which are longitudinally extended to substantially the length of panel 10. At one end of panel 10, generally rectangular, transversely extending connecting header 35 is provided which links up headers 34~ In addition, headers 33 and 34 are connected by connecting portions 36, comprising a plurality of relatively short tubular passageways extend-ing in a direction substantially ~'~
'7~68 transverse to the longitudinally extended headers. Prefer-ably, connecting portions 36 are provided as a plurality of spaced, parallel individual tubes running between header 33 and headers 34, which provide the optimum situs for the heat exchange phenomenon. Also, passageways 30 include entry portion 37 and exit portion 38 extending, respectively, and in opposite direction to each other, from inlet header 33 and connecting header 35, to provide ingress and egress openings for the heat exchange medium In accordance with the present invention as illus-trated in Figure 5, headers 33 and 34 are generally tri-angular in shape and are situated respecting each other whereby the inlet header 33 and the outlet headers 34 possess respective areas of the greatest width at opposite ends of panel 10. The relationship of the configurations of headers 33 and 34 has been found to enhance uniformity of fluid flow, as the differential in velocity of flow between the area of header 33 adjacent the entry portion and the area furthest therefrom is provided for by the reduction in header size at the furthest point. Llkewise, the differential in flow experienced in outlet headers 34 is compensated for by the corresponding differential in header width as fluid builds up to exit the panel. The problem of pressure drop has been dealt with by the pro-vision of connecting portions 36 which are foreshortened in relation to headers _ and 34, as it is believed that the employment of said connecting portions in lengths exceeding those of the corresponding header structures con-tributed to a differential in fluid pressures. Thus, connecting portions 36, though not specifically limited:
-- 10 -- ~
~397~
to a particular dimension, are generally provided in lengths substantially less than that of the longitudinal dimensions of header structures 33 and 34. The residence time of fluid within connecting portions 36 is thus drastically reduced, and the opportunity for pressure drop to occur is corres-pondingly diminished. Fluid thus draining from headers 33 and 34 is able to flow evenly into connecting header 35 where it is transferred out of panel 10 through exit portion 38.
As can be appreciated, the present invention is broadly applicable in a wide variety of designs embodying various modifications to suit the ap~lication of the panel.
Thus, for example, Figure 8 depicts a panel ~0 which employs substantially the same arrangement of headers as set forth in Figure 5, with the exce~tion of the provision of connecting portions 41 in a direcl:ion slightly inclined toward the direction of fluid flow in the horizontal dimension of panel 40. Specifically, connecting portions 41 may be provided to define an angle of at least 91 as ~0 measured in the direction of fluid flow with respect to the longitudinal dimension of panel 40, Connecting portions 41 are inclined at an angle of at least 91, and preferably 92 to 100, measured with respect to the longitudinal dimension of the panel. Though this disposition of the connecting portions is illustrated herein, it is not obligatory and does not form a limitation on the scope of the present invention, as connecting portions may be employed at right angles to the longitudinal dimensions of :
the panel, The primary feature of the present invention is rather the disposition of the various header structures in lQ~7~6~3 the longitudinal dimension in association with the fore-shortened connecting portions, as illustrated in Figure 5, to improve fluid distribution and flow~
A further modification useful in accordance with the present invention is illustrated in Figure 9. In this figure, panel 50 is provided which is substantially identical in configuration to panel 10 illustrated in Figure 5, with the addition of a plurality of bonded portions 51 located intermittently in inlet header 52 and outlet headers 53.
Bonded portions 51 are provided to assist in the inter- -ruption of fluid flow, which serves to reduce the deleterious effects of excess turbulence. Also, bonded portions 51 provide additional strength and structural integrity to headers 52 and 53 which increases their resistance to rup- ' ture under pressure during the employment of panel 50 in a heat exchange system. Though illust~ated as essentially circular islands, bonded portions 5 may be provided in a wide variety of shapes, such as parallel elongated struc-tures defining internal channels, not shown, which would further serve to assist in directing fluid flow within the headers. The foregoing is illustrative of a wide variety of modifications which can be made to the bonded portions _ within the scope of the invention, and the invention should not be construed as limited thereby.
Referring now to Figure 10, an alternate embodi-ment employing essentially the basic structure of the present invention is illustrated. Panel 60 can be seen to be of substantially identical configuration to that of panel 10 in Figure 5, with the exception that two inlet headers 61, each possessing entry portions 62 are provided which corres~
~97~615 pond to outlet headers 34 of panel 10. Fluid thus may enter from two locations into headers 61 where it will pass through foreshortened connecting portions 66 to collect within centrally locatea outlet header 63n Outlet header 63 is identical in configuration to inlet header 33 shown in Figure 5, and headers 61 and 63 are illustrated as of essen-tially triangular shape with their areas of greatest-width located at opposite ends of panel 60~ Fluid draining into outlet header 63 passes out of panel 60 through exit portion 64 corresponding to entry portion 37 in Figure 5. ~s in Figure 5, connecting header 65 ~ corresponding to connecting header 35 is provided between headers 61 adjacent entry portions 62 and serves in this capacity to assure the equal distribution of flow of incoming heat exchange fluid, in the event,for example, the flow through one of ports 62 exceeds that of the other. Naturally, the panel of Figure 10 may be modified by the provision of inclined connecting portions 66 and the inclusion within headers 61 and 63 of a plurality of bonded portions, as disclosed and discussed 20 above with respect to Figures 8 and 9 Figure 11 illustrates an alternate embodiment of -the present invention wherein the panel 70 comprises a fluid distribution pattern defined by the placement of the pattern of the present invention as illustrated in Figure 5 in an abutting relationship to itself. Thus, panel 70 comprises a centrally located header 71 serving as the inlet header for heat exchange fluid which is substantially identical in displacement and configuration to header 33 of Figure 5~
Fluid entering header 71 through entry portion 72 is then 30 directed through a plurality of bonded portions 73 which ~9~7~
extend essentially transversely to communicate with lateral headers _ . Lateral headers 74 are likewise extensions of headers 34 by the provision of identical structures in abutt-ment thereto. Headers 74, like header 71 are essentially tri-angular in shape, however, unlike header 71, possess their area of greatest width at a location approximately inter-mediate their length. Fluid collecting within headers 74 is then directed through connecting portions 73 which flow into central outlet header 75 beariny identical configuration to inlet header 71 Both headers 71 and 75 are identical in shape to header 33 in Figure 5 and are thus essentially tri-angular structures. Fluid collecting in header 75 is then permitted to leave panel 70 through exit portion 76, which corresponds in configuration-and size to entry portion 72~
As can be seen from the Figure, the embodiment of panel 70 does not possess a transversely extending rectangular con-necting header, as no utility for such a structure exists within the context of this panel configuration It should be noted that in all cf the foregoing embodiments of the present invention, the connecting portions of the fluid passageways have been illustrated in parallel, spaced apart relationship to each other. This configuration is preferred but is not obligatory, as connecting portions may be employed which may vary somewhat in size, width, and ~-`
direction which would be suitable for use in accordance with the present invention Though the foregoing description has set forth certain illustrative embodiments, many alternative panel designs may be envisioned by one skilled in the art in accord-ance with the concepts disclosed and described above, and theinvention is accordingly considexed to encompass all such modifications, .. ..
~he panel of the present invention may also comprise a system of tubular passageways for a heat exchange medium defining -2a -:.............. . - .
7~619 at least two longitudinally extended headers extendlng sub-stantially the length of the panel, a connecting header located at one end of the panel interconnecting the longi-tudinally extended headers and lying in a direction trans-verse thereto, generally transversely extending connecting portions of said passageways extending between the respective longitudinally extended headers, and entry and exit portions ext~nding from at least two of said headers to provide ingress and egress openings for the heat exchange medium.
In a preferred embodiment the panel o~ the present ,;
invention comprises at least two longitudinally extended headers of essentially triangular shape,, wherein a single, centrally located inlet header is located between a pair of laterally displaced opposed outlet headers, and said inlet and outlet headers are connected at one end thereof by a transversely extending, substantially rectangularly shaped connecting header, and entry and exit portions are respect-ively provided in extension from said inlet header and said connecting header to provide ingress and egress openings '~
for said heat exchange medium.
The panel of the present invention may possess a wide variation in the configuration of the ~luid distribut-ing pattern to account for variations in size and utility of the particular panel to be prepared. Thus, the panel of the present invention may employ connecting portions disposed at an angle of at least 91 with respect to the longitudinal dimension of the panel to assist in fluid flow. Also, the headers of the present invention may be provided with bonded portions to assist in fluid distribution and to enhance structural stability and resistance to rupture under pressure, 1~9~7~6~
As indicated above, the preferred embodiment of the present invention utilizes a metal panel having a system of internal fluid passageways, conventionally painted blackl as will be described in more detail herein-below. The concepts of the present invention may, howeverl 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 speciically described here- ~;
inbelow utilizing this type of system.
Accordingly, it is a principal object of the present invention to provide a metal panel for use in heat exchange applications which enables the efficient and economical transfer of heat energy.
It is a further object of the present invention to provide a metal panel as aforesaid which is particularly suited for use in a solar energy collector system.
It is yet a further object of the present inven-~O tion to provide a metal panel as aforesaid which is capableof achieving uniform flow at high velocity of a heat exchange medium and a reduction in pressure drop within the passageways of a solar energy collector.
Further objects and advantages will become apparent to those skilled in the art as a detailed des-cription proceeds with reference to the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagram showing schematically the manner in which the panels of the present invention can be ~9'7~6i8 employed.
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 the 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 the panel of the present invention having internal tubular passageways dis-posed between spaced 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.
Figure 7 is an alternate view showing a variation in the tube configuration similar to the view o~ Figure 6, Figures 8, 9, 10 and 11 are top views showing alternate embodiments of the present invention.
DETAILED DESCRIPTIO~
In accordance with the present invention, the ~;
foregoing objects and advantages are readily attained.
The panels of tha present invention ar~ provided with a system of parallel headers connected by fore-shortened connecting por~ions which greatly facilitate flow efficiency and heat exchange.
~L~331'7~61~
As noted earlier, the present invention is directed to the problems of nonuniform flow at reduced velocity, and fluid blockage resulting from the turbulent conditions under which heat exchange panels are operating.
Specifically, the panels are conventionally employed in either the horizontal or the vertical plane whereby fluid entering the panels is under pressure developed by a cir-culating pump or the like, and in the instance of vertical installation, additionally by the force of gravity. The fluid is split within the panel into a plurality of channels through which it passes to effect the heat exchange phenomenon. A problem which has arisen in this arrange-ment results from the turbulence of Eluid movement through the panel which results in a pressure drop between the headers and the connecting portions thereof. This pressure drop causes air pockets to form and tends to impede the movement of fluid. This further results in a reduction in fluid flow and velocity which deleteriously a~fects the efficiency of the panel. The provision of a panel employ-ing a plurality of longitudinally extended headers incombination with connecting passageways of reduced length in accordance with the present invention is believed to cure the aforenoted deficiencies.
The panels of the present invention are prefer-ably utilized in a solar heating system as shown in Figure 1 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 not 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 f~ows along common manifold 13a and is distri-buted into panels 10. me water flows through panels 10, is heated by means of solar energy, is collected in common manifold 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. Alternatively, 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. me solar heating unit of the present invention may be used for residential heating purposes, such as in providing hot water in a residential environ-ment. For example, three panels of the present invention having dimensions of 8 feet x 4 feet would efficiently supply an average household of four with hot water for home use. Alternatively, the solar panels of the present invention may be conveniently used for heating water for swimming pools or for preheating water for domestic gas or oil fired domestic hot water heaters. The fluid is preferably retained in a closed system 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 sunshine 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.
~97~
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 predetermined reading. The pump will then pump the water through the system as generally outlined above, As indicated above, the present invention contem-plates a particularly preferred panel design for optimum efficiency in a solar heating system as described above.
The metal panel or plate of the present invention is desirably fabricated by the ROLL-BO~D~3process 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 superimposed 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 ~o prevent relative movement between the sheets as they are subsequently welded together as shown in Figure 4 by passing through a pair of mill rolls 25 to form welded 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.
m e 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-inhibit-~7~
ing material 22 may then be softened in any appropriatemanner as by annealing, 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 inflated by theintroduction 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. The passageways 30 extend internally within panel 10 and are disposed between spaced apart portior.s of the thickness of said panel. Thus, panel 10 comprises a hollow sheet metal panel or plate having a system of fluid passageways 30 for a heat exchange medium extending internally therein. If the passageways are inflated by the intro,duction 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, t~e resultant passageway configuration has a semicircular shape 32 as shown in Figure 7.
As shown in Figure 5, the passageways 30 include a plurality of headers comprising inlet header 33 and outlet headers 34, all of which are longitudinally extended to substantially the length of panel 10. At one end of panel 10, generally rectangular, transversely extending connecting header 35 is provided which links up headers 34~ In addition, headers 33 and 34 are connected by connecting portions 36, comprising a plurality of relatively short tubular passageways extend-ing in a direction substantially ~'~
'7~68 transverse to the longitudinally extended headers. Prefer-ably, connecting portions 36 are provided as a plurality of spaced, parallel individual tubes running between header 33 and headers 34, which provide the optimum situs for the heat exchange phenomenon. Also, passageways 30 include entry portion 37 and exit portion 38 extending, respectively, and in opposite direction to each other, from inlet header 33 and connecting header 35, to provide ingress and egress openings for the heat exchange medium In accordance with the present invention as illus-trated in Figure 5, headers 33 and 34 are generally tri-angular in shape and are situated respecting each other whereby the inlet header 33 and the outlet headers 34 possess respective areas of the greatest width at opposite ends of panel 10. The relationship of the configurations of headers 33 and 34 has been found to enhance uniformity of fluid flow, as the differential in velocity of flow between the area of header 33 adjacent the entry portion and the area furthest therefrom is provided for by the reduction in header size at the furthest point. Llkewise, the differential in flow experienced in outlet headers 34 is compensated for by the corresponding differential in header width as fluid builds up to exit the panel. The problem of pressure drop has been dealt with by the pro-vision of connecting portions 36 which are foreshortened in relation to headers _ and 34, as it is believed that the employment of said connecting portions in lengths exceeding those of the corresponding header structures con-tributed to a differential in fluid pressures. Thus, connecting portions 36, though not specifically limited:
-- 10 -- ~
~397~
to a particular dimension, are generally provided in lengths substantially less than that of the longitudinal dimensions of header structures 33 and 34. The residence time of fluid within connecting portions 36 is thus drastically reduced, and the opportunity for pressure drop to occur is corres-pondingly diminished. Fluid thus draining from headers 33 and 34 is able to flow evenly into connecting header 35 where it is transferred out of panel 10 through exit portion 38.
As can be appreciated, the present invention is broadly applicable in a wide variety of designs embodying various modifications to suit the ap~lication of the panel.
Thus, for example, Figure 8 depicts a panel ~0 which employs substantially the same arrangement of headers as set forth in Figure 5, with the exce~tion of the provision of connecting portions 41 in a direcl:ion slightly inclined toward the direction of fluid flow in the horizontal dimension of panel 40. Specifically, connecting portions 41 may be provided to define an angle of at least 91 as ~0 measured in the direction of fluid flow with respect to the longitudinal dimension of panel 40, Connecting portions 41 are inclined at an angle of at least 91, and preferably 92 to 100, measured with respect to the longitudinal dimension of the panel. Though this disposition of the connecting portions is illustrated herein, it is not obligatory and does not form a limitation on the scope of the present invention, as connecting portions may be employed at right angles to the longitudinal dimensions of :
the panel, The primary feature of the present invention is rather the disposition of the various header structures in lQ~7~6~3 the longitudinal dimension in association with the fore-shortened connecting portions, as illustrated in Figure 5, to improve fluid distribution and flow~
A further modification useful in accordance with the present invention is illustrated in Figure 9. In this figure, panel 50 is provided which is substantially identical in configuration to panel 10 illustrated in Figure 5, with the addition of a plurality of bonded portions 51 located intermittently in inlet header 52 and outlet headers 53.
Bonded portions 51 are provided to assist in the inter- -ruption of fluid flow, which serves to reduce the deleterious effects of excess turbulence. Also, bonded portions 51 provide additional strength and structural integrity to headers 52 and 53 which increases their resistance to rup- ' ture under pressure during the employment of panel 50 in a heat exchange system. Though illust~ated as essentially circular islands, bonded portions 5 may be provided in a wide variety of shapes, such as parallel elongated struc-tures defining internal channels, not shown, which would further serve to assist in directing fluid flow within the headers. The foregoing is illustrative of a wide variety of modifications which can be made to the bonded portions _ within the scope of the invention, and the invention should not be construed as limited thereby.
Referring now to Figure 10, an alternate embodi-ment employing essentially the basic structure of the present invention is illustrated. Panel 60 can be seen to be of substantially identical configuration to that of panel 10 in Figure 5, with the exception that two inlet headers 61, each possessing entry portions 62 are provided which corres~
~97~615 pond to outlet headers 34 of panel 10. Fluid thus may enter from two locations into headers 61 where it will pass through foreshortened connecting portions 66 to collect within centrally locatea outlet header 63n Outlet header 63 is identical in configuration to inlet header 33 shown in Figure 5, and headers 61 and 63 are illustrated as of essen-tially triangular shape with their areas of greatest-width located at opposite ends of panel 60~ Fluid draining into outlet header 63 passes out of panel 60 through exit portion 64 corresponding to entry portion 37 in Figure 5. ~s in Figure 5, connecting header 65 ~ corresponding to connecting header 35 is provided between headers 61 adjacent entry portions 62 and serves in this capacity to assure the equal distribution of flow of incoming heat exchange fluid, in the event,for example, the flow through one of ports 62 exceeds that of the other. Naturally, the panel of Figure 10 may be modified by the provision of inclined connecting portions 66 and the inclusion within headers 61 and 63 of a plurality of bonded portions, as disclosed and discussed 20 above with respect to Figures 8 and 9 Figure 11 illustrates an alternate embodiment of -the present invention wherein the panel 70 comprises a fluid distribution pattern defined by the placement of the pattern of the present invention as illustrated in Figure 5 in an abutting relationship to itself. Thus, panel 70 comprises a centrally located header 71 serving as the inlet header for heat exchange fluid which is substantially identical in displacement and configuration to header 33 of Figure 5~
Fluid entering header 71 through entry portion 72 is then 30 directed through a plurality of bonded portions 73 which ~9~7~
extend essentially transversely to communicate with lateral headers _ . Lateral headers 74 are likewise extensions of headers 34 by the provision of identical structures in abutt-ment thereto. Headers 74, like header 71 are essentially tri-angular in shape, however, unlike header 71, possess their area of greatest width at a location approximately inter-mediate their length. Fluid collecting within headers 74 is then directed through connecting portions 73 which flow into central outlet header 75 beariny identical configuration to inlet header 71 Both headers 71 and 75 are identical in shape to header 33 in Figure 5 and are thus essentially tri-angular structures. Fluid collecting in header 75 is then permitted to leave panel 70 through exit portion 76, which corresponds in configuration-and size to entry portion 72~
As can be seen from the Figure, the embodiment of panel 70 does not possess a transversely extending rectangular con-necting header, as no utility for such a structure exists within the context of this panel configuration It should be noted that in all cf the foregoing embodiments of the present invention, the connecting portions of the fluid passageways have been illustrated in parallel, spaced apart relationship to each other. This configuration is preferred but is not obligatory, as connecting portions may be employed which may vary somewhat in size, width, and ~-`
direction which would be suitable for use in accordance with the present invention Though the foregoing description has set forth certain illustrative embodiments, many alternative panel designs may be envisioned by one skilled in the art in accord-ance with the concepts disclosed and described above, and theinvention is accordingly considexed to encompass all such modifications, .. ..
Claims (10)
1. A heat exchange panel possessing a system of internal tubular passageways, said tubular passageways defining at least three generally tapered longitudinally extended headers, at least two of said longitudinally extended headers extending sub-stantially the length of said panel, a connecting header located at one end of said panel transverse to and interconnecting longi-tudinally extended headers, and generally transversely extended connecting portions of said passageways, said connecting portions extending between longitudinally extended headers, at least one fluid entry means longitudinally extending from at least one of said headers and at least one fluid exit means longitudinally extending from another of said headers, wherein said longitudi-nally extended headers include a centrally located header offset by a pair of laterally displaced headers.
2. The panel of claim 1 wherein said connecting portions comprise a plurality of spaced parallel individual tubular passageways.
3. The panel of claim 2 wherein said connecting portions are inclined with respect to the direction of fluid flow and are displaced at an angle of at least 91° with respect to the longitudinal dimension of said panel.
4. The panel of claim 3 wherein said connecting portions define an angle of from 92 to 100° with respect to said longi-tudinal dimension.
5. The panel of claim 1 wherein said longitudinally extended headers are essentially triangular in shape and said connecting header is essentially rectangular in shape.
6. The panel of claim 1 wherein said longitudinally extended headers are provided with a plurality of bonded portions which provide interruption in the flow of said heat exchange medium and increase resistance to rupture under pressure.
7. The panel of claim 6 wherein said bonded portions comprise essentially circular islands.
8. The panel of claim 1 wherein said longitudinally extended headers are generally triangularly shaped and comprise said centrally located header flanked by said pair of laterally displaced headers, said laterally displaced headers comprising opposed outlet headers, said inlet header and said outlet headers possess their respective areas of greatest width at opposite ends of said panel, said fluid entry means comprising a single entry portion extending longitudinally away from said inlet header from the area of greatest width thereof, a generally rectangularly shaped connecting header located at the end of said panel furthest from said entry portion, and said exit means comprising a single exit portion extending longitudinally away from said connecting header in the opposite direction to said entry portion.
9. The panel of claim 1 wherein said pair of laterally displaced longitudinally extended headers are generally tri-angularly shaped and comprise opposed inlet headers flanking said centrally located header, which comprises an outlet header, said inlet headers and said outlet header possess their respective areas of greatest width at opposite ends of said panel, said entry means comprising a pair of laterally opposed entry portions extending longitudinally away from said inlet headers from the areas of greatest width thereof, a generally rectangularly shaped connecting header located adjacent and between said entry portions, and said exit means comprising a single exit portion extending longitudinally away from said outlet header in the opposite direction to said entry portions.
10. The panel of claim 1 wherein said longitudinally extended headers comprise a pair of opposed, laterally displaced lateral header structures, and a pair of longitudinally opposed, central header structures located therebetween, and entry and exit means extending longitudinally, respectively, from said central header portions in opposite directions away from each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA301,058A CA1097168A (en) | 1978-04-13 | 1978-04-13 | Solar absorber plate design |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA301,058A CA1097168A (en) | 1978-04-13 | 1978-04-13 | Solar absorber plate design |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1097168A true CA1097168A (en) | 1981-03-10 |
Family
ID=4111225
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA301,058A Expired CA1097168A (en) | 1978-04-13 | 1978-04-13 | Solar absorber plate design |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1097168A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5415155A (en) * | 1993-11-08 | 1995-05-16 | Cohen; Jacques | Modular element with multiple conduits |
-
1978
- 1978-04-13 CA CA301,058A patent/CA1097168A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5415155A (en) * | 1993-11-08 | 1995-05-16 | Cohen; Jacques | Modular element with multiple conduits |
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