CA1104016A - Modular tubular solar energy collector apparatus - Google Patents
Modular tubular solar energy collector apparatusInfo
- Publication number
- CA1104016A CA1104016A CA345,125A CA345125A CA1104016A CA 1104016 A CA1104016 A CA 1104016A CA 345125 A CA345125 A CA 345125A CA 1104016 A CA1104016 A CA 1104016A
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- CA
- Canada
- Prior art keywords
- tube
- collector
- manifold
- liquid
- tubular
- 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.)
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Abstract
The disclosure relates to a modular form of solar energy collector apparatus in which several double-wall glass tube collectors, each with vacuum jacket, depend from opposite sides of an elongated manifold. The manifold includes split halves of foamed polymer insulation and rigid fiberglass reinforced skin thereon, assembled about closed-looped, serpentine liquid carrying tubes preferable of metal or glass in U-tube configurations depending from the manifold halves and extending into the larger double-walled glass tubes, the serpentine tube being connected, respectively, into inlet and outlet header pipes. The interior chamber of the collector tubes is closed by the manifold, thereby enclosing a part of each U-tube branch of the serpentine in a non-turbulent air space. Solar energy collected on the absorber surface of the inner glass tube wall is transmitted to the U-tube and liquid therein. The U-tube within the collectors is blackened and non-reflecting. Principal heat transfer from absorber to U-tube is by radiation with some conduction and convection transfer. The heat transfer liquid is entirely within a closed circuit, which avoids leaks, reduces weight, and cycle time of the liquid is reduced to a fraction of other liquid systems. The manifold and tubes are fastened to a support structure of novel construction enabling fabrication as a module and mounting on a solar exposure of a structure such as a roof, wall or frame. Several modules are interconnectable to desired capacity for a particular solar powered heating or cooling system.
Description
MODULAR TUBUL~R SOLAR E~ERGY
COLLECTOR A~P~P~TUS _ ' The present invention rela.es to apparatus for collection ~, of solar radiation energ~ and transmittal of that energy as I~ heat in a liquid media for purposes of utilization in an energy j consumption system, ¦, BACKGROU~D 0~ THE IMVE~TION
~ icient collectors of.tubular variety are disclosed in ¦~ U. S, Patent ~o~ 3,952,~24 and commonly owne~
!' and U.S. Patent No. 4,033,327, both ~;
1 setting forth inventions of Y, K. Pei in modern, advance~.solar ~1 ¦' collector design, The prior collectors jus~ referred to ~
l, utilize, for the most part, a liquid media to absorb and trans~
. -mit energy as heat collected on a tubular solar absorbing surface ~` of a collector, The liquid is handled in a manifold for series ~ 10w distribution thereof into the interior chamber oE a series : , of absorber tubes. To maintain t~e circuit leakproo~ the ': . . 1 collectors are sealed in the manifold and end pressure on the Ij tube is provided in the structural support to bias the internal " liquid pressure in the interior chamber o the absorber tube as , 20 ~, arise at operating temperatUreS of the s~stem~ The collectors.
: ! are constructed.rom glass tubing components and have an ¦
annular vacuum jacket between the outside tube wall and the . ¦
inside, absorber tube wall, The liquid i.s freely introduced ~rom the manifold into the absorber tube interior by a delivery - 25 tube circuit from which the liquid flows ~ithin the confines o the absorber tube bod~ to the maniLold. Breakage of the ,, ,
COLLECTOR A~P~P~TUS _ ' The present invention rela.es to apparatus for collection ~, of solar radiation energ~ and transmittal of that energy as I~ heat in a liquid media for purposes of utilization in an energy j consumption system, ¦, BACKGROU~D 0~ THE IMVE~TION
~ icient collectors of.tubular variety are disclosed in ¦~ U. S, Patent ~o~ 3,952,~24 and commonly owne~
!' and U.S. Patent No. 4,033,327, both ~;
1 setting forth inventions of Y, K. Pei in modern, advance~.solar ~1 ¦' collector design, The prior collectors jus~ referred to ~
l, utilize, for the most part, a liquid media to absorb and trans~
. -mit energy as heat collected on a tubular solar absorbing surface ~` of a collector, The liquid is handled in a manifold for series ~ 10w distribution thereof into the interior chamber oE a series : , of absorber tubes. To maintain t~e circuit leakproo~ the ': . . 1 collectors are sealed in the manifold and end pressure on the Ij tube is provided in the structural support to bias the internal " liquid pressure in the interior chamber o the absorber tube as , 20 ~, arise at operating temperatUreS of the s~stem~ The collectors.
: ! are constructed.rom glass tubing components and have an ¦
annular vacuum jacket between the outside tube wall and the . ¦
inside, absorber tube wall, The liquid i.s freely introduced ~rom the manifold into the absorber tube interior by a delivery - 25 tube circuit from which the liquid flows ~ithin the confines o the absorber tube bod~ to the maniLold. Breakage of the ,, ,
-2-.. ... ... ... ..
"
~ Q4~
tubular collector, and in particular, breakage of the absorber 'i tube; or unseating and leakage of one of the collector tubes i~
:Erom the mani~old causes leakage or spillage o:E~ liquid ànd a . resultin~ malfunction, or, at best, loss o~ e~icient operation 5 ,. o~ one module segmen~ of the s~stem ~'. . ,, ~
,. SU~RY OF THE I~VE~TION
- Ij The object o~ the invent~on is to provide an improved ~:~
- ,~ advanced solar collec~ion system in which a liquid heat 1~ exchange media is completely containe~ and circulated in a ~ ;
closed tubing circuit to and through the tubular glass collec-: j. tors . .
~; ! In the invention, an important aspect is the elimination ", of water tight seals on the end o~ the collector tube in the ;
manifold without loss o. luid should leakage or breakage ~f . . lS ' the collector tube occur. Also, the system is capable of much higher opexa~ing pressure and temperature operation.
, Anothex important featurè o~ the invention is in the 'i ' ~ , . .
! reduction o~ weight when filled and a lower time constant for liquid cycle circulation. The shorter time constant for the ~ !' ` liquid cycle benefits the control over the heat collection output of the collector. .
:- : The basic structure o the collector tube of the invention ;.- consists in an elongated, double-walled glass tu~e that is ;. closed a-t the one outer end and is open at the ~ther end. The surface of the inner wall o~ the tube is covered with an ' .
a~sorption coating, preferably a wave length selective coating . .
~. . . .
~ 3-~; ~ ~ i.
i having the proper,ies of high absorption and low emissivity The walls are separa~ed by an annular vacuum chamber to reduce conduction and convection loss. The liquid is completely con~
~ tained in manifold and U-tubing as part of the closed circuit ¦. and the U-tube portion is inserted into the interior chamber of the absorber tube wall o~ the collector~ The tubular collector ;
¦l is connected at its open end onto the manifold such that the ¦~ in~erior chamber of the absorber tube in the colle-tor is closed, such as by means of the manifold matrix. The liquid :
o l! circulation system comprised Qf the U-tubing xesides in a ¦
'j stagnant, or non-turbulent air space inside the collector and .1, the radiant solar energy absorbed on the coating of the inner wall of the collector is transmitted as heat through radiatio j. conduction and natural conve~tion transfer to the U-tube and ~ 15 , the liquid circulated therein. 1 ;
- ,' The in~rention also includes a split manifold member formed !~ of a low densit.y insulation body and a dense, non-porous and .. durable exterior skin. The manifold member supports and ¦1 encloses the liquid closed circuit connected as a serpentine , of :tubing incluaing several U-tubes in collectors and clo~sure , for the open end of the collec~or tubes. The serpentine tubing ¦
! is connected to an internal, enclosed header pipe circuit for I ~:
handling ~he incoming and outgoing liquid in the s~stem The manifold in the preferred embodiment herein disclosed includes integral support and mounting standards m-~de as a part of the ~ durable ~xterior skin covering for mounting che apparatus - ', .. .
1, ~4_ . .
, . , ,, , : -. , ~: : ,. ' .
A further feature of the invention includes the modular mounting of the collectors on a frame incorporating into a modular unit the necessary elements of the collector, manifold ~including the closed tubing circuit), reflector means and ;~
supports. The modular construction provided hy the invention enables ground erection of a single moaule or in series grouping of modules on a framework ready for hoisting to the place of instaliation at a desired solar exposure. Installations are most prevalent atop o~ buildings or at elevated locations, and 1~ the ease of installation offered by the invention enhances erection and reliability of the installation.
Since the liquid is completely contained in tubing, hydrostatic testing may be performed as part of the installation ~~ procedure to assure a leak free system. This will be maintained until a tubing rupture occurs. Accordingly, the invention provides improved safety and maintenance advantages. I~ a glass collèctor tube is broken in service, it can be replaced without .
interrupting flow of the liquid or without any loss or spillage of the liquid, i.e. the system need not be shut down. The only loss in the system should a tube be broken would be a performance ef~iciency drop proportionate to the tube or tubes out of service.
Thus, in accordance with the present teachings, there is provided in a solar energy collector apparatus, the combination of a support surfacefor the apparatus exposed to sunlight, a manifold means which is adapted to be mounted on the support, a tubular solar collector which is comprised of a hollow double walled glass tubular collector member having its walls spaced apart and the space therebetween evacuated to sub atmospheric pressure with the collector being opened at one axial end and operating engagement thereat with the mani~old and closed at its opposite axial end. End support means is ;`~
provided engaging the tubular collector member adjacent its closed end and adapted for firmly suppoîting the tubular collector member in a spaced relationship above the support surEace. The manifold means includes an elongated hollow fluid conducting ~;
- U-shaped tube of a thermally conductive material which has one portion including its U-shaped portion extending interiorly of the collector member substantially the axial length of the latter and another portion thereof extending outwardly from the open axial end of the collector member. A body o thermally insulating material is provided surrounding the open end of the collector member and the outwardly extending dependent portion of the U-shaped tube and a heat exchange media in the U-shaped ~-tube being provided adapted for flow throughout the length thereof.
As will be apparent, other objects and advantages will ubd3ubtedly occur to persons skilled in the art from the following description and the accompanying drawings. , ~ : , ' ~' ~ -5a-i s BRIEF DESCRIPTION OF 'THE D~AT,~I~GS
;, FIG. 1 is a perspec~ive view, pa~t~y broken away, of the ¦, modular unit o~ improved solar energy collectors o~ the inven-" tion; :
1, FIG. 2 is a side elevational view, partly broken away, ~ ~ showing the modular unit oF collectors ~ Fig. 1 installed on :
: !! the structural modular ~rame installed at a site exposed to ¦I solar ra~iation.
! FIG. 3 is an exploded perspective view, in part, of one :
¦I mvdular unit o~ the apparatus o~ the invention;
¦, FIG. 4 is a sectional end elevatlonal view taken along , line 4-4 on Fig. l;
FIG. S is an enlarged perspective view of the connector or the serpentine formation of tubing and one of the manifold ¦:
~15 ,¦ heaaer pipes;
:~ ~, FIG, 6 is a side elevational view, partly in section, of i, the connector taken along line 6-6 on Fig. 5;
.
j FIG. 7 is a sectional view of the connector taken along .
~ line 7-7 on Fig. 6;
1 FIG. 8 is a side elevational view of the liquid U-tube '~ portion of the serpentine tubing formation according to the first embodiment o~ the invention; . ~.
;- t, FIG. 9 is an end view of the U-tube shown on Fig. ~;
~; . FIC. 10 is a side elevational view of a li~uid U~tu~e ~. i conduit illustra-ting a further embodiment of the invention in . which the U-tube is ~wisted to lie in a plane near its one end '~ '.
. .
.. .. . .
.
that î, disposed 90 degrees in r~lation to the plane at ~ts other end;
, ~IG. 11 i.s an en~ view o~ the U-tube sho~.m on Fiy lOi ¦~
i and .
5 l~ ~IG. 12 is a perspective view of the ~wisted U-tube :~
¦, embodi~ent shown on Figs. lO and 11 " . DESCRIPTIO~
FIG. 1 illustrates an example o:E the solar ener~
¦~ apparatus module ins~alled on a frame support surface lO, such :
, as the roof or a solar exp~sed wall of a building. q~7e sur~ace :
: ~ lO should be located with best exposure to. the sun, such as a . soutbern exposure in the Northern Hemisphere, etc>. . :
~ A planar diffuse reflector 11 is positionea on top of the ~
!~ ~ramework lO and the solar collector module is moun~ed over the .
~:
~ support lO and re~lector sur~ace 11 and spaced above the upper ~.
l~ surface of the la~ter a prescribed amount to ennance di~use ¦
¦~ reflectlon of the sun's rays. The planar xeflector 11 is like :~
~ . ,~
j that disclosed in commonly owned, U.S. Patent ¦ No. 4,002,162. Alternatively, shaped xeflectors of the :
; .
¦ type disclosed in commonly owned, U.S. Patent No. 4,091,769 ~ :
¦ may be emp].oyed in combination with the tubular collector 7 elements hereof.
,, ~
.The module consists of the manifold assembly 12 and the ';
25 pluralit~ ~f tub~lar solar collector elements 13 ~ich depend , laterally from either side of manifold 12. Thc outer ...
7-- .
, . ~~ , ; ~ ~ ~ ~ . - !
depending closed ends of collector elements 13 are held in an en~ support assembly 14 on an upstandiny bracke~ 15 bolted at ; 16 onto the structur~l beams 76~ For ease OL illustration o~ly ,~-i .` one end support assembly 14 is shown, however, it is understood S ,~ that each of the collector elements 13 is similarly mounted. ~-, The hracket 1'5 is preferably an in~egral piece spanning one ', siae.o~ the manifold for end support o all collector elements :
i ! .
¦l 13 depending along that side, ¦~ The manifold 12 is firmly fastened ~o the support frame ¦
¦i by a pair of downwardly depending feet 33 (to be described later I
. , .:
hereinj of the manifold which are bolted onto the modular ~:
. beams 76. . 1 ;~
!` ~
~ j' THE COLrECTOR i~
; ~, . The collector element 13 is best described with reference , ~ h ~, 15 ~ to Fig. 4O An outer transparen~ g~lass cover tube 18 has a . j ~
conically tapered outer end 19 and has a normally open .,, ,. ~ 1 opposite end 20. The glass walL of end 20 is annularly fused 1 ;
!I to the wall o~ the open end 21 oE the smaller, inwardly disposed glass absorber tube 22, Tube 22 is for~ed prior ~o ¦~
. ,, ~ . : i . 20 ~ fabrication as an absorber of solar radiation energy by virtue of a surace layer of a wave length selecti~e coating possess~
ing properties of high absorption an~ low emissivity, Examples ! ~`
`~ of such coating layer on glass substrates is given , in the commonly owned U,S. Patent No. 4,043,318. The O.D.
of tube 22 is, for example, on the order of 2 inches.
. Preferably, this .
.:
. . . . . .
i`` ' O~
, absorbing coating layer is on the e~ rior sur~ace o~ the glass . . .
absorber tube 22 which has a curved, closed end 23 The space 1 24 between tubes 18 and 22 is evacuated through an end tubula-! tion 25 to a har~ vacuum and shown tipped off in conventional 1I manner after the vacuum is drawn. The vacuum in the space 2a ~! elimina~es convection and conduction heat loss of solar energy ¦~ tha~ is absorbed on the coating sur~ace o~ ~ube 22.
: ¦I To convey the energy absorbed on tube 22 as heat from the j collector elemeni and into use in a s~stem to which the :~ 10 ¦I collector apparatus ~lay be incorporated, ~he invention emplo~s ..
a bent, elongated U-tube 26 of relativel~ small OD (on the ;~
i order o~ 3/8 or 1/2 inch diameter) which is inserted inside the , larger diameter internal chamber 27 o~ absorber tube 22 ~I. Dr !
~ ¦~- ~f abou~ 1-1/2 inches). The remaining area inside chamber 27 lS ~¦~ is a dead.air space, or may be filled with any other gaseous heat ~ransfer media~selected for its properties in transfer of I ~ heat from the glass absorber tube wall to the surface o~ the U-tube 26. Air is a suitable example of such gaseous media.
The U-tube 26 is preferably of duct.ile material which is l :
,. preferably capable of withstanding high pressure and high i' temperature operating con~itions ana which ma~ be readily bent . to a rather sharp reverse bend 26C prescribing the one longitudinal extremity of tube 26. From khe bend at the one ~1 end 26C, the two elongated side-b~-side reaches 26A and 26B
'~ of the tubing extend to the open end of the absorber tube out~
side the end of the double-walled tubular collector elemen~ 13.
~.~ , ' " ,' ~
~ i _ 9 _ !' . i ~' ' j .
4CI ~
~ Depending upon direction of flow induced in tube 26, the e~-! tremities o~ poxtions 26A and 26B provide the inle~ and outlet for fluid circulation along the length o absorber tube 22.
1, As will presently be descr~bed, the tubing 26 ma~ be in-tegral 1, and conti~uous, throughout~ but at leas-t must provide a con-'i tinuous conduit for flow of a liquid heat exc'nange ~edium, ~or ~, example, water, through certain successive elem~nts 13 along the manifold 12. In the example give~ on the drawings, ~low of i the liquid in the system enters the collector element 13 at one 1~ end o~ leg 26B and exits at the end of leg ~6A (Fig. 3).
¦~ The heat transfer in the collector element includes three J~, mechanisms: (1) a radiant hea~ transfer ~rom the inside o~
! t~e glass absorber tube to the U-tube 26, (2) conduction through ¦' the stagnant air space which exists between the U-tube and the 15 ~¦. absorber tube, and (3) natural convection which may be present within the absorber tube. The radia'ion heat transfer is the ominant factor. Conduction through the gas ~ilm (stagnant air) is the second most important heat transfer, and assuming ¦I the tube legs 26~ and 26B are dispo5ed in horizontal side-by-j' side mode (as shown) convection is o minox importance. I~ ¦¦', the tube 26 is positioned such that the tube legs 26A and 26B
1~ are positioned in vertical mode (Figs. 10-12), natural convec~
i tion will contri~ute significantly to the heat ,ransfer. In the horizontal mode, as illustrated on Figs. 8 and 9 herein, . ~ , natural convection will be essentiall~ of negligible a~ount.
Angular disposition of the U-tube botween veFtical and `, !
i : horizontal extremes will increase convection heat transfer . directly in proportion to the increase in the angle ~rom¦- ;
horizontal to vertical. ~ I
! Consi~ering radiation heat ~ransfer as the most dominan~ .
I factor, the U-tube should be made non-reflectin~, which is ¦l accomplished by pro~iding an opa~ue blackened outer surface I, on ~he U-tube to enhance its absorbitivity. The blackened -~-i : layer on tu~e 26 may be a metal oxide layer~ such as copper . ~:
!i oxide, nickel oxide, zinc oxide or iron o~ide, to name a few ~
- 10 1. examples. .
1, The pre~erred example of the invention is a copper tubing jl that is bent ~o U-tube 26 configuration and coated exteriorly i with an opa~ue black oxide material to provide the non--~ -reflecting property.
~lS ~ As is apparent from the structure on Fig. 4, the open end of absorber tube 22 is closed rom ambient atmosphere by :~
~, . ~' ~`~ !t the fit of the collector tube at this end into manifold 1~
~, at the aperture 29 thexein provided, I;
e collector just described performs favorably with ~¦~ the prior li~uid filled collectors. Based on experimen~s, the collector of the present invention is very similar in per ; formance efficiency to ~he tubulax-collector utilizing l /
~ ,. unconfined li~uid (water) circulation throughout the interior ~ .
chamber of absorber tube. The following is an exam~le of ! i per~ormance in which the tubular collector 13 o~ this invention was simultaneously tested with a collector tub~ similarly .
; , ' .
¦', constructed, but in which the water ~as introduced into the j interior of the absorber ~ube thereof by an open ended 5, delivery tube ~illing the chamber of the absorber tube and ~; allowed to ~low along the absorber tube and out its open end 3 5 ~l into a manifold, such as the construction described in the :
,~ ~ :
ji cos~monly owned U.S. Patent No. 4,018,215. ~
: " ::
I TABLE 1 ~ ;
: ¦ ~Staqnant Air Tube Water Fill~ea Tuhe !Insolation Heat Heat ,~ Ra~ Water Collec~ed Collected ¦BT~/hr Ft.~ . Temp. BTU~hr. E~iciencY BTU~hr. Ef~iciency 122F 50.7 52,3% 50,7 j. 150 48,6 50.2 55.4 57.2 I~:
' - 173 45.7 47.2 38.1 3g.3 ;
15 1 114 122F 84.1 56.3% 75.1 49.0% ~ .
..
' 150 76.2 49,7 74,0 173 72.6 47.7 7~.8 47.5 5 Overall average . 50.6% ~8.9%
~, Inso~ar as the U-tube is concerned, its composition may , i . :
I be varied depending upon operating conditions for which the :~
~I solar collector apparatus is designed. The structure of this I :
', invention, just described, enables a wide range of operating .' . ;, ' conditions of the collector, viz high pressu~e and hicJh temperature conditions in the closed and confined heat e~change ~25 .: liquia system. Under these high temperature, hi~h pressure conditions~ the liquid con~ined in the system including the , .' , . .
~. . i ~ - !
~ tubes and header pipes are capable o~ operatiny pressures.up !~``
" to 1600 PSI and to temperatures to the order o~ 600F. There-
"
~ Q4~
tubular collector, and in particular, breakage of the absorber 'i tube; or unseating and leakage of one of the collector tubes i~
:Erom the mani~old causes leakage or spillage o:E~ liquid ànd a . resultin~ malfunction, or, at best, loss o~ e~icient operation 5 ,. o~ one module segmen~ of the s~stem ~'. . ,, ~
,. SU~RY OF THE I~VE~TION
- Ij The object o~ the invent~on is to provide an improved ~:~
- ,~ advanced solar collec~ion system in which a liquid heat 1~ exchange media is completely containe~ and circulated in a ~ ;
closed tubing circuit to and through the tubular glass collec-: j. tors . .
~; ! In the invention, an important aspect is the elimination ", of water tight seals on the end o~ the collector tube in the ;
manifold without loss o. luid should leakage or breakage ~f . . lS ' the collector tube occur. Also, the system is capable of much higher opexa~ing pressure and temperature operation.
, Anothex important featurè o~ the invention is in the 'i ' ~ , . .
! reduction o~ weight when filled and a lower time constant for liquid cycle circulation. The shorter time constant for the ~ !' ` liquid cycle benefits the control over the heat collection output of the collector. .
:- : The basic structure o the collector tube of the invention ;.- consists in an elongated, double-walled glass tu~e that is ;. closed a-t the one outer end and is open at the ~ther end. The surface of the inner wall o~ the tube is covered with an ' .
a~sorption coating, preferably a wave length selective coating . .
~. . . .
~ 3-~; ~ ~ i.
i having the proper,ies of high absorption and low emissivity The walls are separa~ed by an annular vacuum chamber to reduce conduction and convection loss. The liquid is completely con~
~ tained in manifold and U-tubing as part of the closed circuit ¦. and the U-tube portion is inserted into the interior chamber of the absorber tube wall o~ the collector~ The tubular collector ;
¦l is connected at its open end onto the manifold such that the ¦~ in~erior chamber of the absorber tube in the colle-tor is closed, such as by means of the manifold matrix. The liquid :
o l! circulation system comprised Qf the U-tubing xesides in a ¦
'j stagnant, or non-turbulent air space inside the collector and .1, the radiant solar energy absorbed on the coating of the inner wall of the collector is transmitted as heat through radiatio j. conduction and natural conve~tion transfer to the U-tube and ~ 15 , the liquid circulated therein. 1 ;
- ,' The in~rention also includes a split manifold member formed !~ of a low densit.y insulation body and a dense, non-porous and .. durable exterior skin. The manifold member supports and ¦1 encloses the liquid closed circuit connected as a serpentine , of :tubing incluaing several U-tubes in collectors and clo~sure , for the open end of the collec~or tubes. The serpentine tubing ¦
! is connected to an internal, enclosed header pipe circuit for I ~:
handling ~he incoming and outgoing liquid in the s~stem The manifold in the preferred embodiment herein disclosed includes integral support and mounting standards m-~de as a part of the ~ durable ~xterior skin covering for mounting che apparatus - ', .. .
1, ~4_ . .
, . , ,, , : -. , ~: : ,. ' .
A further feature of the invention includes the modular mounting of the collectors on a frame incorporating into a modular unit the necessary elements of the collector, manifold ~including the closed tubing circuit), reflector means and ;~
supports. The modular construction provided hy the invention enables ground erection of a single moaule or in series grouping of modules on a framework ready for hoisting to the place of instaliation at a desired solar exposure. Installations are most prevalent atop o~ buildings or at elevated locations, and 1~ the ease of installation offered by the invention enhances erection and reliability of the installation.
Since the liquid is completely contained in tubing, hydrostatic testing may be performed as part of the installation ~~ procedure to assure a leak free system. This will be maintained until a tubing rupture occurs. Accordingly, the invention provides improved safety and maintenance advantages. I~ a glass collèctor tube is broken in service, it can be replaced without .
interrupting flow of the liquid or without any loss or spillage of the liquid, i.e. the system need not be shut down. The only loss in the system should a tube be broken would be a performance ef~iciency drop proportionate to the tube or tubes out of service.
Thus, in accordance with the present teachings, there is provided in a solar energy collector apparatus, the combination of a support surfacefor the apparatus exposed to sunlight, a manifold means which is adapted to be mounted on the support, a tubular solar collector which is comprised of a hollow double walled glass tubular collector member having its walls spaced apart and the space therebetween evacuated to sub atmospheric pressure with the collector being opened at one axial end and operating engagement thereat with the mani~old and closed at its opposite axial end. End support means is ;`~
provided engaging the tubular collector member adjacent its closed end and adapted for firmly suppoîting the tubular collector member in a spaced relationship above the support surEace. The manifold means includes an elongated hollow fluid conducting ~;
- U-shaped tube of a thermally conductive material which has one portion including its U-shaped portion extending interiorly of the collector member substantially the axial length of the latter and another portion thereof extending outwardly from the open axial end of the collector member. A body o thermally insulating material is provided surrounding the open end of the collector member and the outwardly extending dependent portion of the U-shaped tube and a heat exchange media in the U-shaped ~-tube being provided adapted for flow throughout the length thereof.
As will be apparent, other objects and advantages will ubd3ubtedly occur to persons skilled in the art from the following description and the accompanying drawings. , ~ : , ' ~' ~ -5a-i s BRIEF DESCRIPTION OF 'THE D~AT,~I~GS
;, FIG. 1 is a perspec~ive view, pa~t~y broken away, of the ¦, modular unit o~ improved solar energy collectors o~ the inven-" tion; :
1, FIG. 2 is a side elevational view, partly broken away, ~ ~ showing the modular unit oF collectors ~ Fig. 1 installed on :
: !! the structural modular ~rame installed at a site exposed to ¦I solar ra~iation.
! FIG. 3 is an exploded perspective view, in part, of one :
¦I mvdular unit o~ the apparatus o~ the invention;
¦, FIG. 4 is a sectional end elevatlonal view taken along , line 4-4 on Fig. l;
FIG. S is an enlarged perspective view of the connector or the serpentine formation of tubing and one of the manifold ¦:
~15 ,¦ heaaer pipes;
:~ ~, FIG, 6 is a side elevational view, partly in section, of i, the connector taken along line 6-6 on Fig. 5;
.
j FIG. 7 is a sectional view of the connector taken along .
~ line 7-7 on Fig. 6;
1 FIG. 8 is a side elevational view of the liquid U-tube '~ portion of the serpentine tubing formation according to the first embodiment o~ the invention; . ~.
;- t, FIG. 9 is an end view of the U-tube shown on Fig. ~;
~; . FIC. 10 is a side elevational view of a li~uid U~tu~e ~. i conduit illustra-ting a further embodiment of the invention in . which the U-tube is ~wisted to lie in a plane near its one end '~ '.
. .
.. .. . .
.
that î, disposed 90 degrees in r~lation to the plane at ~ts other end;
, ~IG. 11 i.s an en~ view o~ the U-tube sho~.m on Fiy lOi ¦~
i and .
5 l~ ~IG. 12 is a perspective view of the ~wisted U-tube :~
¦, embodi~ent shown on Figs. lO and 11 " . DESCRIPTIO~
FIG. 1 illustrates an example o:E the solar ener~
¦~ apparatus module ins~alled on a frame support surface lO, such :
, as the roof or a solar exp~sed wall of a building. q~7e sur~ace :
: ~ lO should be located with best exposure to. the sun, such as a . soutbern exposure in the Northern Hemisphere, etc>. . :
~ A planar diffuse reflector 11 is positionea on top of the ~
!~ ~ramework lO and the solar collector module is moun~ed over the .
~:
~ support lO and re~lector sur~ace 11 and spaced above the upper ~.
l~ surface of the la~ter a prescribed amount to ennance di~use ¦
¦~ reflectlon of the sun's rays. The planar xeflector 11 is like :~
~ . ,~
j that disclosed in commonly owned, U.S. Patent ¦ No. 4,002,162. Alternatively, shaped xeflectors of the :
; .
¦ type disclosed in commonly owned, U.S. Patent No. 4,091,769 ~ :
¦ may be emp].oyed in combination with the tubular collector 7 elements hereof.
,, ~
.The module consists of the manifold assembly 12 and the ';
25 pluralit~ ~f tub~lar solar collector elements 13 ~ich depend , laterally from either side of manifold 12. Thc outer ...
7-- .
, . ~~ , ; ~ ~ ~ ~ . - !
depending closed ends of collector elements 13 are held in an en~ support assembly 14 on an upstandiny bracke~ 15 bolted at ; 16 onto the structur~l beams 76~ For ease OL illustration o~ly ,~-i .` one end support assembly 14 is shown, however, it is understood S ,~ that each of the collector elements 13 is similarly mounted. ~-, The hracket 1'5 is preferably an in~egral piece spanning one ', siae.o~ the manifold for end support o all collector elements :
i ! .
¦l 13 depending along that side, ¦~ The manifold 12 is firmly fastened ~o the support frame ¦
¦i by a pair of downwardly depending feet 33 (to be described later I
. , .:
hereinj of the manifold which are bolted onto the modular ~:
. beams 76. . 1 ;~
!` ~
~ j' THE COLrECTOR i~
; ~, . The collector element 13 is best described with reference , ~ h ~, 15 ~ to Fig. 4O An outer transparen~ g~lass cover tube 18 has a . j ~
conically tapered outer end 19 and has a normally open .,, ,. ~ 1 opposite end 20. The glass walL of end 20 is annularly fused 1 ;
!I to the wall o~ the open end 21 oE the smaller, inwardly disposed glass absorber tube 22, Tube 22 is for~ed prior ~o ¦~
. ,, ~ . : i . 20 ~ fabrication as an absorber of solar radiation energy by virtue of a surace layer of a wave length selecti~e coating possess~
ing properties of high absorption an~ low emissivity, Examples ! ~`
`~ of such coating layer on glass substrates is given , in the commonly owned U,S. Patent No. 4,043,318. The O.D.
of tube 22 is, for example, on the order of 2 inches.
. Preferably, this .
.:
. . . . . .
i`` ' O~
, absorbing coating layer is on the e~ rior sur~ace o~ the glass . . .
absorber tube 22 which has a curved, closed end 23 The space 1 24 between tubes 18 and 22 is evacuated through an end tubula-! tion 25 to a har~ vacuum and shown tipped off in conventional 1I manner after the vacuum is drawn. The vacuum in the space 2a ~! elimina~es convection and conduction heat loss of solar energy ¦~ tha~ is absorbed on the coating sur~ace o~ ~ube 22.
: ¦I To convey the energy absorbed on tube 22 as heat from the j collector elemeni and into use in a s~stem to which the :~ 10 ¦I collector apparatus ~lay be incorporated, ~he invention emplo~s ..
a bent, elongated U-tube 26 of relativel~ small OD (on the ;~
i order o~ 3/8 or 1/2 inch diameter) which is inserted inside the , larger diameter internal chamber 27 o~ absorber tube 22 ~I. Dr !
~ ¦~- ~f abou~ 1-1/2 inches). The remaining area inside chamber 27 lS ~¦~ is a dead.air space, or may be filled with any other gaseous heat ~ransfer media~selected for its properties in transfer of I ~ heat from the glass absorber tube wall to the surface o~ the U-tube 26. Air is a suitable example of such gaseous media.
The U-tube 26 is preferably of duct.ile material which is l :
,. preferably capable of withstanding high pressure and high i' temperature operating con~itions ana which ma~ be readily bent . to a rather sharp reverse bend 26C prescribing the one longitudinal extremity of tube 26. From khe bend at the one ~1 end 26C, the two elongated side-b~-side reaches 26A and 26B
'~ of the tubing extend to the open end of the absorber tube out~
side the end of the double-walled tubular collector elemen~ 13.
~.~ , ' " ,' ~
~ i _ 9 _ !' . i ~' ' j .
4CI ~
~ Depending upon direction of flow induced in tube 26, the e~-! tremities o~ poxtions 26A and 26B provide the inle~ and outlet for fluid circulation along the length o absorber tube 22.
1, As will presently be descr~bed, the tubing 26 ma~ be in-tegral 1, and conti~uous, throughout~ but at leas-t must provide a con-'i tinuous conduit for flow of a liquid heat exc'nange ~edium, ~or ~, example, water, through certain successive elem~nts 13 along the manifold 12. In the example give~ on the drawings, ~low of i the liquid in the system enters the collector element 13 at one 1~ end o~ leg 26B and exits at the end of leg ~6A (Fig. 3).
¦~ The heat transfer in the collector element includes three J~, mechanisms: (1) a radiant hea~ transfer ~rom the inside o~
! t~e glass absorber tube to the U-tube 26, (2) conduction through ¦' the stagnant air space which exists between the U-tube and the 15 ~¦. absorber tube, and (3) natural convection which may be present within the absorber tube. The radia'ion heat transfer is the ominant factor. Conduction through the gas ~ilm (stagnant air) is the second most important heat transfer, and assuming ¦I the tube legs 26~ and 26B are dispo5ed in horizontal side-by-j' side mode (as shown) convection is o minox importance. I~ ¦¦', the tube 26 is positioned such that the tube legs 26A and 26B
1~ are positioned in vertical mode (Figs. 10-12), natural convec~
i tion will contri~ute significantly to the heat ,ransfer. In the horizontal mode, as illustrated on Figs. 8 and 9 herein, . ~ , natural convection will be essentiall~ of negligible a~ount.
Angular disposition of the U-tube botween veFtical and `, !
i : horizontal extremes will increase convection heat transfer . directly in proportion to the increase in the angle ~rom¦- ;
horizontal to vertical. ~ I
! Consi~ering radiation heat ~ransfer as the most dominan~ .
I factor, the U-tube should be made non-reflectin~, which is ¦l accomplished by pro~iding an opa~ue blackened outer surface I, on ~he U-tube to enhance its absorbitivity. The blackened -~-i : layer on tu~e 26 may be a metal oxide layer~ such as copper . ~:
!i oxide, nickel oxide, zinc oxide or iron o~ide, to name a few ~
- 10 1. examples. .
1, The pre~erred example of the invention is a copper tubing jl that is bent ~o U-tube 26 configuration and coated exteriorly i with an opa~ue black oxide material to provide the non--~ -reflecting property.
~lS ~ As is apparent from the structure on Fig. 4, the open end of absorber tube 22 is closed rom ambient atmosphere by :~
~, . ~' ~`~ !t the fit of the collector tube at this end into manifold 1~
~, at the aperture 29 thexein provided, I;
e collector just described performs favorably with ~¦~ the prior li~uid filled collectors. Based on experimen~s, the collector of the present invention is very similar in per ; formance efficiency to ~he tubulax-collector utilizing l /
~ ,. unconfined li~uid (water) circulation throughout the interior ~ .
chamber of absorber tube. The following is an exam~le of ! i per~ormance in which the tubular collector 13 o~ this invention was simultaneously tested with a collector tub~ similarly .
; , ' .
¦', constructed, but in which the water ~as introduced into the j interior of the absorber ~ube thereof by an open ended 5, delivery tube ~illing the chamber of the absorber tube and ~; allowed to ~low along the absorber tube and out its open end 3 5 ~l into a manifold, such as the construction described in the :
,~ ~ :
ji cos~monly owned U.S. Patent No. 4,018,215. ~
: " ::
I TABLE 1 ~ ;
: ¦ ~Staqnant Air Tube Water Fill~ea Tuhe !Insolation Heat Heat ,~ Ra~ Water Collec~ed Collected ¦BT~/hr Ft.~ . Temp. BTU~hr. E~iciencY BTU~hr. Ef~iciency 122F 50.7 52,3% 50,7 j. 150 48,6 50.2 55.4 57.2 I~:
' - 173 45.7 47.2 38.1 3g.3 ;
15 1 114 122F 84.1 56.3% 75.1 49.0% ~ .
..
' 150 76.2 49,7 74,0 173 72.6 47.7 7~.8 47.5 5 Overall average . 50.6% ~8.9%
~, Inso~ar as the U-tube is concerned, its composition may , i . :
I be varied depending upon operating conditions for which the :~
~I solar collector apparatus is designed. The structure of this I :
', invention, just described, enables a wide range of operating .' . ;, ' conditions of the collector, viz high pressu~e and hicJh temperature conditions in the closed and confined heat e~change ~25 .: liquia system. Under these high temperature, hi~h pressure conditions~ the liquid con~ined in the system including the , .' , . .
~. . i ~ - !
~ tubes and header pipes are capable o~ operatiny pressures.up !~``
" to 1600 PSI and to temperatures to the order o~ 600F. There-
3. fore, the U-tube may be constructed of most metals including 1, l~ copper, brass, steel or steel alloys, stainless steel, ~' aluminum, to name the more co~mon metal compositions. Also the U-tube may be made o~ glass which possesses good inert ~
¦~ properties in handllng a heat exchange liquid, such as water. .
The preferred construction of the tubing serpentine and ...
I header pipes is steel tubing, principally for the sake of ~! stre~gth an~ cost. Copper tubing, as earlier indicated, is also a ver~ satisfactory material for this part of the }' ~pparatus. -I ¦~ The tubing s~stem of the apparatus provicles a shortened 1~`
¦! residence time in th.e collectors and provides the benefit of 1S ~ better control in the overall system fox utilization of the energy. Weight reduction too is an important factor in the invention. As an example, the liquid filled collector system, .~ such as described in the above-mentioned patent 1' o~ common ownership, utilizes 9 gallons o~ water in a ~wenty- ¦
, four tube colIector module. The present invention constructed j ~ ~:
:~ t~ with 3/~ diameter tubing of the same size module holds 1.5 .
: l gallons of liquid in the serpentine tubin~ plus 0.33 gallon 1~ 1.' in the 1" diameter header pipes. For flow rate of 0.3 gallon .
~- ~` per minute, the residence time of the liquid in such module is reduced from 30 minutes in ~he.prior liquid-~illed collector .. sys~em to 3.6 minutes in the present invention.
1, .
- i . ~, .
:~: 1. -13- l l; ~
: !i ~
il ~
Under certain lower pressure/temperature operations, the U-tube may also be made of rigid plastics in common use today, ~, however, care in selection o~ these must be taXen because o~
', the possibility of failure or rupture under too high pressure !~ or temperature conditions in the liquid circulated through the ~ U-tu~e.
ii To reduce radiation loss to a minimum in the U-tube, any of i! the materials suggested may be surface coated or clad by known ¦~ technicfues to provide a blacl~ened, non-re~lective coating on ¦, the U-tube, at least over that portion of the U-~ube con-tained li within the collector element 13. -Accordingly, without sacrifice o~ performance efficiency,under the present invention the advantages alluded to herein '~ are practically o~tainable. ¦;~
~ 15 i In the description of the invention herein and illustrated ';~
-': I' . I-:¦i on the araw7ngs, the U-tube structure is integrally constructed ; ~, for a series of the tubular collectors 13 in a module for the ', sa~e of convenience. However, the serp~ntine U-tube series may be constructed of pieces of tubing connected ~ogether, and 1l certain portions thereo~ may be made of dif~erent materials of 1`
¦i suf~icient strength to reduce cost in construction o~ the in- ¦
vention. ~or example, each of the U-~ubes in the collector may be fabricated of copper tubing, as indicated, and these connected together into the serpen-tine series, as illustrated, i' ~25 ~ by tubing of a different, lower cost material. In this regard, ; certain combinations of materials to achieve cost effecti~eness i ;~ , ~, , li ~
of the system are well ~ithin the skill o~ arti~ans in this field.
Simil~rly, materials may be selected in ~abrication of the header pipes of -the modules, descri~ed above, or cost ! e~ectiveness in a given set o~ operating conditions. Since ' the pre~erred examples are described using waker as the heat j!
¦i exchange liquid media in the collector elements, steel or I!
!I copper have been sele~ted for ease o~ fabri~ation OL corrosion ¦ resis-tance or protection against electrolytic ef~ect in the 1` system. The invention is not li~ited to such materials, however. The one advan~age of the invention mus~ be okserved. -j~ The li~uid is confined in the solar collector apparatus for I
; i ! ~! ~ ' ¦!, flow be~ween the p~int o~ collection of -the ener~y in the i~ . ~.
t system and to a transer point in the part of the system in ;~
j' . . I ',.: :`
~15 ll~ which the ener~y is either utilized or stored.
THE MANIFOLD
t~,~ As best sho~n on Fig. 3, the manifold 12 is comprised of j `
¦ complementary upper and lower half sections 30 and 31r respectively, ~ modular length. Each of sections 30 and 31 j, ~are preferably molded in the following fashion. A sXeet .
molding compound (SMCj in sheet form is first draped over th~
mold cavity and heated to a pliable, softened consistency.
The SMC is then pressed into the cavity of the mold setting ~; . , ~.i --- . ~ . .
the exterior skin layer 32 of each piece. The S~ilC material is . ; .
~25 one tha~ is co~mercially available from several manufacturers, such as ~ R. Grace Company and ~.~ens-Corning Fiberglas i Corporati~n. Such ma-terial is comprised oE a poly2s~er com-position that is reinforc2d with imbedded fibers or strands ~f glass (fiberglass). The polyester is a thermosetting plastic ' compound After the S~lC skin layer is shaped in the mold 5 ~I`i cavity, it is cured u~der suficient temperature, well known l~ in the ar~, ~or a time 5such as 20-30 seconds) ~o rendex ~he ¦~ thermosetting plastic rigid. The result is the exterior skin layer 32, represented specifically on Fig. 4, which ~orms a ~1 durable, dense, non~porous exterior covering for the manifold~
, Any desired pigmentation or color may be blended into the SMC
'j~ material for an attractive appearance of the manifold. At the time of molding sXin 32, just described, the cavity of the mold l~ used incorporates the contour for forming the leg supports 33 : ~ ¦ for the manifold (see Figs~ 2-4), which are disposed at the 15 ! longitudinal ends o lower half section 31. Thus, the underside !
support brackets for each modular manifold length are made integral with skin layer 32 and ~rom the same reinforced thermo-;
se~ting material.
~ A~ter the SMC material is molded to shape and cured in J
i! the mold, the shell of the skin 32 provides a cavity into ~, j which is molded a matri~ o~ low aensity thermal insulating ! material, such as foa~ed polyurethane of 4-6 lbs. per cubic ., foot density. The foamed polyurethane maLerial i5 placed in ~ the hollow interior of the shape lormed as skin 32 and molded to a contour by known technique, such as by a die plat~en having cores and channels, for shapin~ the interior cavity ` !, -16-.~ ~. . . 1.
Lf~
1;:
portions of the mo~ular mani:Eold sections 30 and 31. As seen on Fig. 3, the insulation material is molded to shape two 1 side-by-side, longitudinally extending channels 3~ an~ 35 in ! `
lower section 31 ~or xeceiving -two header pipes 36 and 37, ! respectively. At the lateral outside eages of channels 34 and :-~35 there are two smaller, spaced-apar~, lateral, paral~el 1l channels 38 and 39 of approximately semi-circular configura-t tion through each end wall 40 o~ the recessed serni-circular ~
.; j, , , , . . .
' cavity wall 4l forme~ in the insulation and sXin layer 32.
1~ There are several of these shaped cavit~ walls 4l, ao along ! each ~ongituainal side of manifold 12 for receiving the open :~;
,!
~, end of a double-walled glass collector tube 13~ The spaced, , ~: parallel, lateral channels 38 and 39 in each collector tube -~
~ `
; , aperture wall are provided in complementary matching fas'nion ..
15~ in both~ the upper and lower manifold sections 30, 31 so that, in a juxtaposed relationship of the sections, the channels 38, ¦
; !. 39 will receive and surround the legs 26A and 26~, respec~
. ¦ tively, o~ U-tube 26.
1~ In thé formation of skin layer 32, there is also formed : 20 ~¦~ a semi-circular -Elange 42 having a~gasXet receiving groove -3 ¦ ~
; 1, formed thereby around the edge o~ the collector-tube receiving : -:
,. aperture. A circular rubber grommet 44 is seatea in ~he com-bined upper a~d lower semi-circular grooves 43 t~hich retain the ~-i annular gasXet 4a when the sections 30, 31 are juxtapositioned ::: j ) ~
- 25 in their assembly (such as shown at the right-hand side o~ , :
Fig. 3). The upper half section 30 is fastened to the lo~er :.~ . . ;: , . ', ') ' :.
`~ , -17-!~
half section 31 by a horseshoe style of U~clamp 45 comprised of the therrnosetting polyester material ~o match the skin ~2.
Clamp 45 has some resiliency and is forced over the upper halE
i` :" section 30 at opposite ends of the m~dule length thereof.
', Lateral, spaced apart exterior ribs 46 are formed inte~ral on i skin 32 at the ends of section 30. The ribs ~6 of adjacent ¦~ manifold module lengths receive a clamp iS to locate it with ~ ~
j stability and gulde it to its seat on the lower section 31 ;i ; ¦~ which is comprised of integral exterior lugs 47 on the skin ¦', layer 32 thereof. As shown at the right side of Fig. 3, one ¦~ lug 47 is in circumferential allgnment with its opposite rib !1 46 at each end of section 31 and the inner ~acing, spaced cam ;
', lugs 48 on each of the depending ends of horseshoe clamp 45 i. snap over a lug 47 This snap fit holds the top section 30 1;
lS ¦'~ onto lower section 31 closing the manifold about the header tubes 36 and 37 and the U-tube serpentine comprised of the ~t' series of U-tubes 26 and lengths o~ tubing 26D interconnectiny ¦~ one U-tube to the next. The downwardly depending spaced edges ¦~, 49 of clamp 45 fit along the o posite outside edges of the ribs ¦¦ 46 of ad~acent manifold Iengths and clamp the t~o together in ¦
j, end-to-end abutting attachment~ !
' The tube serpentine formation (the series of U-tubes 26 and intermediate lengths 26D ccnnecting them together) is mad2 to correspond in its number of U-tubes and in its U-tube center-to-center spacing with the center spacing of the number of circular pocXets 41 ~or the collector tubes 13 along one -.,, -,, ; .
!; ~ i 1104~)16 ; ~
:
.
side o~ the mani~old. These tub2 poc~ets are defined by the , walls 40, 41 inwardly o-E the grommet flange 42 in each of the 1~ modular lengths of the manifold, as descri~ed earlier. The j i~, forward (inlet) end of the le~t side serpentine of the manifold ~
¦, is connected to threads 50A of a connector block 50 on header .1 :
i, pipe 36 ~Fig. 5) by a flared, threaded pressure fitting 51 (phantom outline on Fig. 7). Connector block 50 has a curv~d, j contoured lower face and is welded onto 'Lhe periphery of inlet 1~ header pipe 36 to align the ra~ial passage 52 in the block with ~i a punched aperture 53 in the wall of header pipe 36. Passage : ~ 52 forms a T-connection with the latera1 passage 54 in block ! 50 and passage 5~ has the female threads 50~ in the block at :;;
¦' each end thereof for astening the threaded serpentine end . " fittings 51 and 55, respectively. The fitting 55 i5 the inlet ~: si l' :
¦' en~ threaded fittin~ on the right hand serpentine (Fig. 3) r 1~
~' : li . ~ .
¦~ m usIy, the ~wo se.rpentine tubing formations for the right and :
' le~t hand sides of the collector manifold are connected into 1:~
the inlet header pipe 36. Similarly, the outlet ends of each ~ :
¦! f these seFpentine tubing formations are connect~d into a 1¦ connector block 56 (cons~ructed the same as blocX 50) which is 1~ ;
1, welded onto outlet header pipe 37 over a punched aperture ~: ~ therein located along the manifold near its far end. In the ,:
,. fashion described for t'ne inlet connection, the other terminal ~; i' ena of each of the two serpentine tubing formations are ,:
r i` pressure-~ittin~ connected into the lateral passage of ;~ connector block 56 ~hich in turn is internally connected to :
, ;. .
~ i,' ' ' `
~ ,. -19- . :
!
. 1,, - outlet header pipe 37. The interior web 5g o~ the low density ` insulation betwoen pipe ch~nnels 34 and 35 rormed therein is provided with similar recesses 60 to receive the block !~ connectors 50 and 5&, respectively, adjacent opposite ends OL
~, the module.
, Any number of the mani~old module ~engths ma~ be connected ; I' end-to-ena by the pipe couplers 57 and 58 ~or connecting the ! far end oE the inLet header pipe 36 and outlet header pipe 37, :
respectivelyJ to the near end of the same elements 36, 37 ji ~superimposed in phantom outline at the riyht-hand side of ¦l ~ig. 31 in the.next module of the manifold. ~n the far end of f ! the last module in an installation, end caps (not shown) replace :
,. the pipe couplers 5~ and 58. With the just described connec- ~:~
1 tions made, the manifold sections 30, 31 are.closed along an I. overlapping seam line 120 (Fig. 2). Each of the serpentine ~ .
¦~ tubing formations is now connected ~o the inlet header pipe ~6 at one end and to the outlet header plpe 37 at the other end.
uid heat exchanye media supply Ln the system installed for I
¦l utilization of collected solar energy may be connected, as the :
1~ inlet to the collector at the pipe 36. A suitable li~uid fox this purpose is water, which has a high sp2cific heat. By ¦~ orcing flo-~ or the liquid in the system, such as by a po~er l i driven pump, the liquid is introduced by ~he inlet header pipe ~; , 36 into each of the tubing serpentines of the s~rstem ~or flow ~25 I successively th~ough each of the U-tubes 26 in the collectors : . 13 disposed alon~ one side of each module. By e~change of the .i ' , .
~ , 20 .. solar ~nergy collected by the tubular collec~ors 13 as heat to j. the liquid in the closed tubing 26, the energy is carried from I. each of the serpentin~s into the outlet header pipe 37, which '~ is in turn connected into ~he system receiving the energy.
,. The pipes 36 and 37 are held in a block 61 (Fig. 3~ of ¦ insulation material and a formed end cap 62 is fastened onto t~ the one end face 63 of the assembled manifold. A suitable i assembl~ of end cap 62 is by an RTV, silicone rubber adhesive ¦~ which cures at room temperature~ Such adhesives are commer- .
j. cially availa~le. End cap 62 is made the same as the sections l:
, 30, 31 in that an SMC material is molded as the high densi.t~
outer skin (32) thereof and a low density core of the ~oamed .
~' polyurethane insulation material is formed to a shape inside ~ this skin or shell. An appropriate recess 61A (shown by ' .
¦~ - dotted outline) in the body of ~h~ end cap is ~olded.to receive l`:
insulator blocX 61 and the bend portions o pipes 36 and 37. ~ ~
i Suitable insulation about the pipes 36r 37 emanating below l ~ :
. I end cap 62, such as shown at 68 on Fig~ 2, will of course be ¦ : ;
~ provided to avoid unnecessary heat loss in the circulation of 1 liquid through the system~
t ~. As best shown on Figs. 2 and 4, the several tubular .
: co1lectors 13 assembled as eaxlier described herein are in~
~:~ serted over the U-tubes 26 depending outwardly from the manifold aperture at flange 42. The open end of tube 13 butts . ~ :
~ ~gainst the insulation wall 40 at the back o~ th~ tube pocket 29 in the manifold and b~ this means substantially .:;~ ,, i ,~
: i. 1 ~ ~ ~ 9iL V ~
`' closes the open end of the collec-cor tube. The atmosphere - inside the tube i5 enclosed and is non-turbulent (dead air space). This provides the media to transfer energy (heat) i absorbed on the coating of tube 22 inside the collect3r )' chamber 27 to the U-tube 26 and in turn to the liquid cixcu~
~ lated therein~ The double wall section (18~ 22) at the end ¦~
;~ of each collector tube 13 is inserted within the mani~old pocket such that the gromm~t ~asXet 4~ annularly engages the ¦~
' outer sur~ace of cover tube 18 in a cross-sectional area f 1~;
10 ¦ the double-wall tube that includes the annular vacuum 1;~
, chambex 24 ~ormed by the two glass wal~s (18, 22)~ This is '~¦ important to prev nt heat loss by the collector through con-duction and convection, i.e. a vacuum jacketed, insulated l;;
part of the collector tube 13 is inside the grommet 44 in the ii - . . . - ~
lS ~, manifold aperture pocket and sealed b~ the gasket 44.
j The outer closed end 19 of the collector~s cover tube 18 is supported by the end cap 14 and bracket 15 in the following ',' manner. 'The closed end 19 of the glass cover tube 18 is Il pr~erably tapered to a substantially\conical shape that in- l;
i cludes tubulation 25 through which the vacuum is pulled to evacuate th~ ann~lar chamber 27 between the tube walls 18 and 22. There is a plastic end fitment 65 ~Fig. 4) placed over - the end o~ the sealed tube on glass end portion 19 thereof - , which protects the glass surface from abrasion, scratching and , 25 abuse in service. This fiLment includes the series of in-wardly facin~ annular ribs 66 engaging the glass. The op-n, .- ,; , . i ', ,' ',', ., ,. ' ~,, , . . ~ , . .
!
7 1 :
; l~rge end of fitment 65 includes an annular, out~Jardly project-ing, ring-like cnd enlargement 67 of the fitment. The bullet-shaped outer end cap 14 is made in split conLiguration and . encircles the end fitment 65 engaging the latter securely so ! as to somewhat compress the ring-like portion 67 of the itment ' annularly against the glass surface of cover tube 18. The end , cap 14 is held in the engagement just describe~ on the end I, bracket 15 in the~following manner. Brac~et 15 is comprised l~ of its upstanding legs 71 at either longitudinal end there~f~
,`l The lower ena oE leg 71 is boltec~ onto the beams 76 o* the ¦, modular frame ~o be presently described) by a pair of lower , bolts 16. Spanning between the legs 71 at either end of the ! bracket there is a~ integral lower web section 69 including the i; -il spaced-apart, semi-circular halves of the end cap. The axial 5 17, centers of the end caps are coaxially located with respect to ¦
! the centers of the respective installed collector tubes ! supported by the manifold. FiLst the collector tubes inser~ed ¦~
.; . .
¦i over tubes 26 and in the manifold pockets 29 rest in place on i, the lower section o~ the truncated outer caps 14~ Next, an 1 ;
;~ 20 Il upper, retainer member 73 is placed onto the ma~ching top lip ! ;~
. 72 of section 69. The retainer member 73 includes corresponding semi-circular trunca-ted halves which match with the semi~
circular lower halves and to~ether form the end cap 14 fox !;:
each collector tube 13. ~he retainer me~ber 73 is securely fastened at the ends onto he legs 71 and section 69 by cap - scréws 75. The assembled end bracket 15 and the encircling _~3-~4~L6 end caps 14 hold each collector tube Eirmly in position. In l the present invention, there i5 no requi.rement for the end cap : to provide an axial compressisn load o~ the collector tube to .;
I retain it in the manifold, there being no internal pressure ,. applied inside the absorber tube chamber 27 to tend to force ¦.
j, 1:`
1. the collector tube axially out of the manifold. Accordingly, ¦~
: ~, the force placed on the end of the collector tube.by the end ¦
" moun~ing, just described, need onl~ be suf~icient to ~irmly ¦, suppor~. the tube against vibration as may be caused by exterior ¦
1 forces, suc'n as wind and weather.
. MODULAR ASSEL~LY
',' The mani~old 12, collectors 13 and end bracket supports 15 ¦
.. 1 are incorporated into a modular assembly, as shown on Figs. 1-4 j A pair of cross beams 76 of structural material, such as steel j or aluminum, are placed parallel and mani~old lower section 31 3, 1 lS bolted in place on the ~lange of the beams by studs 33A ~:
~', molded.into legs 33. These beams 76 are preerably selected 1;
:~ , according to the following. The end module of an installation includes an L-shaped beam at one end Intermediat.e modùles are ~-20 ~ l' constructed with a T-shaped beam having the wider web at the top thereof. Adjacen~ module assemblies have the mani~old legs ' 33 bolted onto the same web of the T-beam~ Similarly, the end l ; -.
! bracke-t 15 has its legs 71 bolted to the top web spaced beams,,,~, "
~ 76. The reflector shee~ 11 is installed on the ~rame work 10, ~;
25 ; such as the roof of a building. Over sheet 11 there are two U-shape~ brackets 7V each fastened by d scre~ 74 through the :~
, ~ , .
~ -24~
reflector. The brackets 70 are installed as pairs aligned to receive each of the beams 76 and suppor~ them in parallel , fashion.
' As seen on Figs~ 1, 2 and 4, each bracket 70 has a slot 77 ,-j in the upright sides thereof which receives a pin 78 Pin 78 j~
' is inserted through a hole provided in ~he proper location on ' the vertical section of the beams 76 Thus, the modular units ~;~
of the apparatus after assembly over the beams 76 are hoisted 1~
j to the brackets 70 and supported by the pins 78 fitted into ¦-1, ~he proper slots 77 of the U~brackets 70.
I This construction permits ground site assembly of all of ; the parts of a module assembly o~ the solar collector . I
, .
apparatus. This assembled module ~ay then be hoisted into ¦' place on a so]ar exposure site of a building or ~ramework and j-lS "~ there fastened into place~ Of course, the Liquid connections i~ to the header pipes 36 and 37 will be made a~er the module i or modules arP located in place and fastened together. I~iuS, , the system is connected ror circulation of the liquid through , the several serpentines o~ tubing by flow between the inlet and ; ;. . , j' ~outlet header pipes. Tne flow rate of the liquid on the installation framework (or building) will be limited to the volume of the header pipes and the serpentine tubing of the j~
, particular installation. This volume is less in ~/eigh~ than '~ the liquid collec~ors utilized here-to~ore i~ which liquid flo~i ..
~ through the system fil~ed the absorb r tubes and manifoldin~
all times Moreover, breal~age of a tube collector of the module -25- ~, will not result in loss oE liquid or malfunction of the module.
i Since the li~uid is confined in this serpentin2 tubing circuit an~ the header pipes, the loss of liquid or potential d~lmage by spilled liquid is obviated.
~ Also, the closed system for li~uid in the present inven~
J~ tion permits design o~ ver~ high pressure units - up to '. 3000 PSI -- and at very high temperatures - in the area of , 1600F -- enabLing use of the solar collector apparatus in ' power generating applications.
lG j SECOND E~ODIMENT `~
I' ~s shown on Figs. 10-12, the serpentine arra~ of tubing 260 may be constructed such that the depending legs 261 and , 262 depend outwardly from the connector section of tubing 263 j in an over and under relationship. The reverse, U-bend portion ! 264 of the tubing at the far end of each U-tube is tt~isted, ` that is, the section 26~ at one end lies in a plane 90 degrees .
j from the plane at the bend 264. Thus the serpentine of tubing i~
which, in the first e~bodiment, lay principally along one l`
, plane, this serpentine construction has the U-tube ~e~t into ', two planes at right angles to each other (see Fig A 12).
This form of the invention has advantages in providing a fall or drop Eor the liquid in the U-tubes for draining ~hem , , if desired. The performance and efficiency of the collector - remains about the same as in the irst embodiment The assembly of the tubing serpentine into the glass, double-t~all tube collectors 13 is the same as before. Th~ cut-outs in .
.. . ..
.
-: , , . j .. ..... . ..
., ~ , ., :
~. the mani~old matrix (bc-st seen at 38, 39 on Fig 3) utilized ,.
i in the first embodiment may need ~o be revised to correspor.,d 7ith this moaiEication. ~ssentiall~, the balance of the ,~
! apparatus of the invention des~ribed earlier herein remains ~;
. . "~
5 ,. the same. :~
J~ The moaule concept herein described and included in the i' preferred embodimert, utilizes tubular solar energy collectors .
!, depending from both longitudinal sides of the manifoldO It ~
I' is also within the scope of the invention to arrange the :;
i,i manifold such that the collectors depend alony but one side j ¦~ thereoE. ~ur~her, the manifold ma~ be structured under this ji invention to a form other than a straight, elongated ~igure, I ~
! , ~; ~, ¦'. should a particular solar exposure structure or installation 1;:
ii ~ be better suited to a modification o~ this st~le. .. : :.
;15 S~ Other and further modifications ma~ likewise be resortea j ~
to without departing from the spirit and scope of the appended i~i.``
, claims.
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¦~ properties in handllng a heat exchange liquid, such as water. .
The preferred construction of the tubing serpentine and ...
I header pipes is steel tubing, principally for the sake of ~! stre~gth an~ cost. Copper tubing, as earlier indicated, is also a ver~ satisfactory material for this part of the }' ~pparatus. -I ¦~ The tubing s~stem of the apparatus provicles a shortened 1~`
¦! residence time in th.e collectors and provides the benefit of 1S ~ better control in the overall system fox utilization of the energy. Weight reduction too is an important factor in the invention. As an example, the liquid filled collector system, .~ such as described in the above-mentioned patent 1' o~ common ownership, utilizes 9 gallons o~ water in a ~wenty- ¦
, four tube colIector module. The present invention constructed j ~ ~:
:~ t~ with 3/~ diameter tubing of the same size module holds 1.5 .
: l gallons of liquid in the serpentine tubin~ plus 0.33 gallon 1~ 1.' in the 1" diameter header pipes. For flow rate of 0.3 gallon .
~- ~` per minute, the residence time of the liquid in such module is reduced from 30 minutes in ~he.prior liquid-~illed collector .. sys~em to 3.6 minutes in the present invention.
1, .
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:~: 1. -13- l l; ~
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Under certain lower pressure/temperature operations, the U-tube may also be made of rigid plastics in common use today, ~, however, care in selection o~ these must be taXen because o~
', the possibility of failure or rupture under too high pressure !~ or temperature conditions in the liquid circulated through the ~ U-tu~e.
ii To reduce radiation loss to a minimum in the U-tube, any of i! the materials suggested may be surface coated or clad by known ¦~ technicfues to provide a blacl~ened, non-re~lective coating on ¦, the U-tube, at least over that portion of the U-~ube con-tained li within the collector element 13. -Accordingly, without sacrifice o~ performance efficiency,under the present invention the advantages alluded to herein '~ are practically o~tainable. ¦;~
~ 15 i In the description of the invention herein and illustrated ';~
-': I' . I-:¦i on the araw7ngs, the U-tube structure is integrally constructed ; ~, for a series of the tubular collectors 13 in a module for the ', sa~e of convenience. However, the serp~ntine U-tube series may be constructed of pieces of tubing connected ~ogether, and 1l certain portions thereo~ may be made of dif~erent materials of 1`
¦i suf~icient strength to reduce cost in construction o~ the in- ¦
vention. ~or example, each of the U-~ubes in the collector may be fabricated of copper tubing, as indicated, and these connected together into the serpen-tine series, as illustrated, i' ~25 ~ by tubing of a different, lower cost material. In this regard, ; certain combinations of materials to achieve cost effecti~eness i ;~ , ~, , li ~
of the system are well ~ithin the skill o~ arti~ans in this field.
Simil~rly, materials may be selected in ~abrication of the header pipes of -the modules, descri~ed above, or cost ! e~ectiveness in a given set o~ operating conditions. Since ' the pre~erred examples are described using waker as the heat j!
¦i exchange liquid media in the collector elements, steel or I!
!I copper have been sele~ted for ease o~ fabri~ation OL corrosion ¦ resis-tance or protection against electrolytic ef~ect in the 1` system. The invention is not li~ited to such materials, however. The one advan~age of the invention mus~ be okserved. -j~ The li~uid is confined in the solar collector apparatus for I
; i ! ~! ~ ' ¦!, flow be~ween the p~int o~ collection of -the ener~y in the i~ . ~.
t system and to a transer point in the part of the system in ;~
j' . . I ',.: :`
~15 ll~ which the ener~y is either utilized or stored.
THE MANIFOLD
t~,~ As best sho~n on Fig. 3, the manifold 12 is comprised of j `
¦ complementary upper and lower half sections 30 and 31r respectively, ~ modular length. Each of sections 30 and 31 j, ~are preferably molded in the following fashion. A sXeet .
molding compound (SMCj in sheet form is first draped over th~
mold cavity and heated to a pliable, softened consistency.
The SMC is then pressed into the cavity of the mold setting ~; . , ~.i --- . ~ . .
the exterior skin layer 32 of each piece. The S~ilC material is . ; .
~25 one tha~ is co~mercially available from several manufacturers, such as ~ R. Grace Company and ~.~ens-Corning Fiberglas i Corporati~n. Such ma-terial is comprised oE a poly2s~er com-position that is reinforc2d with imbedded fibers or strands ~f glass (fiberglass). The polyester is a thermosetting plastic ' compound After the S~lC skin layer is shaped in the mold 5 ~I`i cavity, it is cured u~der suficient temperature, well known l~ in the ar~, ~or a time 5such as 20-30 seconds) ~o rendex ~he ¦~ thermosetting plastic rigid. The result is the exterior skin layer 32, represented specifically on Fig. 4, which ~orms a ~1 durable, dense, non~porous exterior covering for the manifold~
, Any desired pigmentation or color may be blended into the SMC
'j~ material for an attractive appearance of the manifold. At the time of molding sXin 32, just described, the cavity of the mold l~ used incorporates the contour for forming the leg supports 33 : ~ ¦ for the manifold (see Figs~ 2-4), which are disposed at the 15 ! longitudinal ends o lower half section 31. Thus, the underside !
support brackets for each modular manifold length are made integral with skin layer 32 and ~rom the same reinforced thermo-;
se~ting material.
~ A~ter the SMC material is molded to shape and cured in J
i! the mold, the shell of the skin 32 provides a cavity into ~, j which is molded a matri~ o~ low aensity thermal insulating ! material, such as foa~ed polyurethane of 4-6 lbs. per cubic ., foot density. The foamed polyurethane maLerial i5 placed in ~ the hollow interior of the shape lormed as skin 32 and molded to a contour by known technique, such as by a die plat~en having cores and channels, for shapin~ the interior cavity ` !, -16-.~ ~. . . 1.
Lf~
1;:
portions of the mo~ular mani:Eold sections 30 and 31. As seen on Fig. 3, the insulation material is molded to shape two 1 side-by-side, longitudinally extending channels 3~ an~ 35 in ! `
lower section 31 ~or xeceiving -two header pipes 36 and 37, ! respectively. At the lateral outside eages of channels 34 and :-~35 there are two smaller, spaced-apar~, lateral, paral~el 1l channels 38 and 39 of approximately semi-circular configura-t tion through each end wall 40 o~ the recessed serni-circular ~
.; j, , , , . . .
' cavity wall 4l forme~ in the insulation and sXin layer 32.
1~ There are several of these shaped cavit~ walls 4l, ao along ! each ~ongituainal side of manifold 12 for receiving the open :~;
,!
~, end of a double-walled glass collector tube 13~ The spaced, , ~: parallel, lateral channels 38 and 39 in each collector tube -~
~ `
; , aperture wall are provided in complementary matching fas'nion ..
15~ in both~ the upper and lower manifold sections 30, 31 so that, in a juxtaposed relationship of the sections, the channels 38, ¦
; !. 39 will receive and surround the legs 26A and 26~, respec~
. ¦ tively, o~ U-tube 26.
1~ In thé formation of skin layer 32, there is also formed : 20 ~¦~ a semi-circular -Elange 42 having a~gasXet receiving groove -3 ¦ ~
; 1, formed thereby around the edge o~ the collector-tube receiving : -:
,. aperture. A circular rubber grommet 44 is seatea in ~he com-bined upper a~d lower semi-circular grooves 43 t~hich retain the ~-i annular gasXet 4a when the sections 30, 31 are juxtapositioned ::: j ) ~
- 25 in their assembly (such as shown at the right-hand side o~ , :
Fig. 3). The upper half section 30 is fastened to the lo~er :.~ . . ;: , . ', ') ' :.
`~ , -17-!~
half section 31 by a horseshoe style of U~clamp 45 comprised of the therrnosetting polyester material ~o match the skin ~2.
Clamp 45 has some resiliency and is forced over the upper halE
i` :" section 30 at opposite ends of the m~dule length thereof.
', Lateral, spaced apart exterior ribs 46 are formed inte~ral on i skin 32 at the ends of section 30. The ribs ~6 of adjacent ¦~ manifold module lengths receive a clamp iS to locate it with ~ ~
j stability and gulde it to its seat on the lower section 31 ;i ; ¦~ which is comprised of integral exterior lugs 47 on the skin ¦', layer 32 thereof. As shown at the right side of Fig. 3, one ¦~ lug 47 is in circumferential allgnment with its opposite rib !1 46 at each end of section 31 and the inner ~acing, spaced cam ;
', lugs 48 on each of the depending ends of horseshoe clamp 45 i. snap over a lug 47 This snap fit holds the top section 30 1;
lS ¦'~ onto lower section 31 closing the manifold about the header tubes 36 and 37 and the U-tube serpentine comprised of the ~t' series of U-tubes 26 and lengths o~ tubing 26D interconnectiny ¦~ one U-tube to the next. The downwardly depending spaced edges ¦~, 49 of clamp 45 fit along the o posite outside edges of the ribs ¦¦ 46 of ad~acent manifold Iengths and clamp the t~o together in ¦
j, end-to-end abutting attachment~ !
' The tube serpentine formation (the series of U-tubes 26 and intermediate lengths 26D ccnnecting them together) is mad2 to correspond in its number of U-tubes and in its U-tube center-to-center spacing with the center spacing of the number of circular pocXets 41 ~or the collector tubes 13 along one -.,, -,, ; .
!; ~ i 1104~)16 ; ~
:
.
side o~ the mani~old. These tub2 poc~ets are defined by the , walls 40, 41 inwardly o-E the grommet flange 42 in each of the 1~ modular lengths of the manifold, as descri~ed earlier. The j i~, forward (inlet) end of the le~t side serpentine of the manifold ~
¦, is connected to threads 50A of a connector block 50 on header .1 :
i, pipe 36 ~Fig. 5) by a flared, threaded pressure fitting 51 (phantom outline on Fig. 7). Connector block 50 has a curv~d, j contoured lower face and is welded onto 'Lhe periphery of inlet 1~ header pipe 36 to align the ra~ial passage 52 in the block with ~i a punched aperture 53 in the wall of header pipe 36. Passage : ~ 52 forms a T-connection with the latera1 passage 54 in block ! 50 and passage 5~ has the female threads 50~ in the block at :;;
¦' each end thereof for astening the threaded serpentine end . " fittings 51 and 55, respectively. The fitting 55 i5 the inlet ~: si l' :
¦' en~ threaded fittin~ on the right hand serpentine (Fig. 3) r 1~
~' : li . ~ .
¦~ m usIy, the ~wo se.rpentine tubing formations for the right and :
' le~t hand sides of the collector manifold are connected into 1:~
the inlet header pipe 36. Similarly, the outlet ends of each ~ :
¦! f these seFpentine tubing formations are connect~d into a 1¦ connector block 56 (cons~ructed the same as blocX 50) which is 1~ ;
1, welded onto outlet header pipe 37 over a punched aperture ~: ~ therein located along the manifold near its far end. In the ,:
,. fashion described for t'ne inlet connection, the other terminal ~; i' ena of each of the two serpentine tubing formations are ,:
r i` pressure-~ittin~ connected into the lateral passage of ;~ connector block 56 ~hich in turn is internally connected to :
, ;. .
~ i,' ' ' `
~ ,. -19- . :
!
. 1,, - outlet header pipe 37. The interior web 5g o~ the low density ` insulation betwoen pipe ch~nnels 34 and 35 rormed therein is provided with similar recesses 60 to receive the block !~ connectors 50 and 5&, respectively, adjacent opposite ends OL
~, the module.
, Any number of the mani~old module ~engths ma~ be connected ; I' end-to-ena by the pipe couplers 57 and 58 ~or connecting the ! far end oE the inLet header pipe 36 and outlet header pipe 37, :
respectivelyJ to the near end of the same elements 36, 37 ji ~superimposed in phantom outline at the riyht-hand side of ¦l ~ig. 31 in the.next module of the manifold. ~n the far end of f ! the last module in an installation, end caps (not shown) replace :
,. the pipe couplers 5~ and 58. With the just described connec- ~:~
1 tions made, the manifold sections 30, 31 are.closed along an I. overlapping seam line 120 (Fig. 2). Each of the serpentine ~ .
¦~ tubing formations is now connected ~o the inlet header pipe ~6 at one end and to the outlet header plpe 37 at the other end.
uid heat exchanye media supply Ln the system installed for I
¦l utilization of collected solar energy may be connected, as the :
1~ inlet to the collector at the pipe 36. A suitable li~uid fox this purpose is water, which has a high sp2cific heat. By ¦~ orcing flo-~ or the liquid in the system, such as by a po~er l i driven pump, the liquid is introduced by ~he inlet header pipe ~; , 36 into each of the tubing serpentines of the s~rstem ~or flow ~25 I successively th~ough each of the U-tubes 26 in the collectors : . 13 disposed alon~ one side of each module. By e~change of the .i ' , .
~ , 20 .. solar ~nergy collected by the tubular collec~ors 13 as heat to j. the liquid in the closed tubing 26, the energy is carried from I. each of the serpentin~s into the outlet header pipe 37, which '~ is in turn connected into ~he system receiving the energy.
,. The pipes 36 and 37 are held in a block 61 (Fig. 3~ of ¦ insulation material and a formed end cap 62 is fastened onto t~ the one end face 63 of the assembled manifold. A suitable i assembl~ of end cap 62 is by an RTV, silicone rubber adhesive ¦~ which cures at room temperature~ Such adhesives are commer- .
j. cially availa~le. End cap 62 is made the same as the sections l:
, 30, 31 in that an SMC material is molded as the high densi.t~
outer skin (32) thereof and a low density core of the ~oamed .
~' polyurethane insulation material is formed to a shape inside ~ this skin or shell. An appropriate recess 61A (shown by ' .
¦~ - dotted outline) in the body of ~h~ end cap is ~olded.to receive l`:
insulator blocX 61 and the bend portions o pipes 36 and 37. ~ ~
i Suitable insulation about the pipes 36r 37 emanating below l ~ :
. I end cap 62, such as shown at 68 on Fig~ 2, will of course be ¦ : ;
~ provided to avoid unnecessary heat loss in the circulation of 1 liquid through the system~
t ~. As best shown on Figs. 2 and 4, the several tubular .
: co1lectors 13 assembled as eaxlier described herein are in~
~:~ serted over the U-tubes 26 depending outwardly from the manifold aperture at flange 42. The open end of tube 13 butts . ~ :
~ ~gainst the insulation wall 40 at the back o~ th~ tube pocket 29 in the manifold and b~ this means substantially .:;~ ,, i ,~
: i. 1 ~ ~ ~ 9iL V ~
`' closes the open end of the collec-cor tube. The atmosphere - inside the tube i5 enclosed and is non-turbulent (dead air space). This provides the media to transfer energy (heat) i absorbed on the coating of tube 22 inside the collect3r )' chamber 27 to the U-tube 26 and in turn to the liquid cixcu~
~ lated therein~ The double wall section (18~ 22) at the end ¦~
;~ of each collector tube 13 is inserted within the mani~old pocket such that the gromm~t ~asXet 4~ annularly engages the ¦~
' outer sur~ace of cover tube 18 in a cross-sectional area f 1~;
10 ¦ the double-wall tube that includes the annular vacuum 1;~
, chambex 24 ~ormed by the two glass wal~s (18, 22)~ This is '~¦ important to prev nt heat loss by the collector through con-duction and convection, i.e. a vacuum jacketed, insulated l;;
part of the collector tube 13 is inside the grommet 44 in the ii - . . . - ~
lS ~, manifold aperture pocket and sealed b~ the gasket 44.
j The outer closed end 19 of the collector~s cover tube 18 is supported by the end cap 14 and bracket 15 in the following ',' manner. 'The closed end 19 of the glass cover tube 18 is Il pr~erably tapered to a substantially\conical shape that in- l;
i cludes tubulation 25 through which the vacuum is pulled to evacuate th~ ann~lar chamber 27 between the tube walls 18 and 22. There is a plastic end fitment 65 ~Fig. 4) placed over - the end o~ the sealed tube on glass end portion 19 thereof - , which protects the glass surface from abrasion, scratching and , 25 abuse in service. This fiLment includes the series of in-wardly facin~ annular ribs 66 engaging the glass. The op-n, .- ,; , . i ', ,' ',', ., ,. ' ~,, , . . ~ , . .
!
7 1 :
; l~rge end of fitment 65 includes an annular, out~Jardly project-ing, ring-like cnd enlargement 67 of the fitment. The bullet-shaped outer end cap 14 is made in split conLiguration and . encircles the end fitment 65 engaging the latter securely so ! as to somewhat compress the ring-like portion 67 of the itment ' annularly against the glass surface of cover tube 18. The end , cap 14 is held in the engagement just describe~ on the end I, bracket 15 in the~following manner. Brac~et 15 is comprised l~ of its upstanding legs 71 at either longitudinal end there~f~
,`l The lower ena oE leg 71 is boltec~ onto the beams 76 o* the ¦, modular frame ~o be presently described) by a pair of lower , bolts 16. Spanning between the legs 71 at either end of the ! bracket there is a~ integral lower web section 69 including the i; -il spaced-apart, semi-circular halves of the end cap. The axial 5 17, centers of the end caps are coaxially located with respect to ¦
! the centers of the respective installed collector tubes ! supported by the manifold. FiLst the collector tubes inser~ed ¦~
.; . .
¦i over tubes 26 and in the manifold pockets 29 rest in place on i, the lower section o~ the truncated outer caps 14~ Next, an 1 ;
;~ 20 Il upper, retainer member 73 is placed onto the ma~ching top lip ! ;~
. 72 of section 69. The retainer member 73 includes corresponding semi-circular trunca-ted halves which match with the semi~
circular lower halves and to~ether form the end cap 14 fox !;:
each collector tube 13. ~he retainer me~ber 73 is securely fastened at the ends onto he legs 71 and section 69 by cap - scréws 75. The assembled end bracket 15 and the encircling _~3-~4~L6 end caps 14 hold each collector tube Eirmly in position. In l the present invention, there i5 no requi.rement for the end cap : to provide an axial compressisn load o~ the collector tube to .;
I retain it in the manifold, there being no internal pressure ,. applied inside the absorber tube chamber 27 to tend to force ¦.
j, 1:`
1. the collector tube axially out of the manifold. Accordingly, ¦~
: ~, the force placed on the end of the collector tube.by the end ¦
" moun~ing, just described, need onl~ be suf~icient to ~irmly ¦, suppor~. the tube against vibration as may be caused by exterior ¦
1 forces, suc'n as wind and weather.
. MODULAR ASSEL~LY
',' The mani~old 12, collectors 13 and end bracket supports 15 ¦
.. 1 are incorporated into a modular assembly, as shown on Figs. 1-4 j A pair of cross beams 76 of structural material, such as steel j or aluminum, are placed parallel and mani~old lower section 31 3, 1 lS bolted in place on the ~lange of the beams by studs 33A ~:
~', molded.into legs 33. These beams 76 are preerably selected 1;
:~ , according to the following. The end module of an installation includes an L-shaped beam at one end Intermediat.e modùles are ~-20 ~ l' constructed with a T-shaped beam having the wider web at the top thereof. Adjacen~ module assemblies have the mani~old legs ' 33 bolted onto the same web of the T-beam~ Similarly, the end l ; -.
! bracke-t 15 has its legs 71 bolted to the top web spaced beams,,,~, "
~ 76. The reflector shee~ 11 is installed on the ~rame work 10, ~;
25 ; such as the roof of a building. Over sheet 11 there are two U-shape~ brackets 7V each fastened by d scre~ 74 through the :~
, ~ , .
~ -24~
reflector. The brackets 70 are installed as pairs aligned to receive each of the beams 76 and suppor~ them in parallel , fashion.
' As seen on Figs~ 1, 2 and 4, each bracket 70 has a slot 77 ,-j in the upright sides thereof which receives a pin 78 Pin 78 j~
' is inserted through a hole provided in ~he proper location on ' the vertical section of the beams 76 Thus, the modular units ~;~
of the apparatus after assembly over the beams 76 are hoisted 1~
j to the brackets 70 and supported by the pins 78 fitted into ¦-1, ~he proper slots 77 of the U~brackets 70.
I This construction permits ground site assembly of all of ; the parts of a module assembly o~ the solar collector . I
, .
apparatus. This assembled module ~ay then be hoisted into ¦' place on a so]ar exposure site of a building or ~ramework and j-lS "~ there fastened into place~ Of course, the Liquid connections i~ to the header pipes 36 and 37 will be made a~er the module i or modules arP located in place and fastened together. I~iuS, , the system is connected ror circulation of the liquid through , the several serpentines o~ tubing by flow between the inlet and ; ;. . , j' ~outlet header pipes. Tne flow rate of the liquid on the installation framework (or building) will be limited to the volume of the header pipes and the serpentine tubing of the j~
, particular installation. This volume is less in ~/eigh~ than '~ the liquid collec~ors utilized here-to~ore i~ which liquid flo~i ..
~ through the system fil~ed the absorb r tubes and manifoldin~
all times Moreover, breal~age of a tube collector of the module -25- ~, will not result in loss oE liquid or malfunction of the module.
i Since the li~uid is confined in this serpentin2 tubing circuit an~ the header pipes, the loss of liquid or potential d~lmage by spilled liquid is obviated.
~ Also, the closed system for li~uid in the present inven~
J~ tion permits design o~ ver~ high pressure units - up to '. 3000 PSI -- and at very high temperatures - in the area of , 1600F -- enabLing use of the solar collector apparatus in ' power generating applications.
lG j SECOND E~ODIMENT `~
I' ~s shown on Figs. 10-12, the serpentine arra~ of tubing 260 may be constructed such that the depending legs 261 and , 262 depend outwardly from the connector section of tubing 263 j in an over and under relationship. The reverse, U-bend portion ! 264 of the tubing at the far end of each U-tube is tt~isted, ` that is, the section 26~ at one end lies in a plane 90 degrees .
j from the plane at the bend 264. Thus the serpentine of tubing i~
which, in the first e~bodiment, lay principally along one l`
, plane, this serpentine construction has the U-tube ~e~t into ', two planes at right angles to each other (see Fig A 12).
This form of the invention has advantages in providing a fall or drop Eor the liquid in the U-tubes for draining ~hem , , if desired. The performance and efficiency of the collector - remains about the same as in the irst embodiment The assembly of the tubing serpentine into the glass, double-t~all tube collectors 13 is the same as before. Th~ cut-outs in .
.. . ..
.
-: , , . j .. ..... . ..
., ~ , ., :
~. the mani~old matrix (bc-st seen at 38, 39 on Fig 3) utilized ,.
i in the first embodiment may need ~o be revised to correspor.,d 7ith this moaiEication. ~ssentiall~, the balance of the ,~
! apparatus of the invention des~ribed earlier herein remains ~;
. . "~
5 ,. the same. :~
J~ The moaule concept herein described and included in the i' preferred embodimert, utilizes tubular solar energy collectors .
!, depending from both longitudinal sides of the manifoldO It ~
I' is also within the scope of the invention to arrange the :;
i,i manifold such that the collectors depend alony but one side j ¦~ thereoE. ~ur~her, the manifold ma~ be structured under this ji invention to a form other than a straight, elongated ~igure, I ~
! , ~; ~, ¦'. should a particular solar exposure structure or installation 1;:
ii ~ be better suited to a modification o~ this st~le. .. : :.
;15 S~ Other and further modifications ma~ likewise be resortea j ~
to without departing from the spirit and scope of the appended i~i.``
, claims.
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Claims (3)
1. In a solar energy collector apparatus, the combina-tion of a support surface for said apparatus exposed to sun-light, a manifold means adapted to be mounted on said support, a tubular solar collector comprised of a hollow double walled glass tubular collector member having its walls spaced apart and the space therebetween evacuated to sub-atmospheric pressure, said collector being open at one axial end and in operating engagement thereat with the manifold and closed at its opposite axial end, end support means engaging the tubular collector member adjacent its closed end adapted for firmly supporting said tubular collector member in a spaced relationship above said support surface, said manifold means including an elongated, hollow, fluid conducting U-shaped tube of a thermally conductive material having one portion including its U-shaped portion extending interiorly of said collector member substantially the axial length of the latter and another portion thereof extending outwardly from said open axial end of said collector member, a body of thermally insulating material surrounding the open end of said collector member and the outwardly extending dependent portion of said U-shaped tube, and a heat exchange media in said U-shaped tube adapted for flow throughout the length thereof.
2. The apparatus of claim 1 in which the end support means comprises an end cap inserted over the closed end of said tubular collector and annularly engaging the exterior thereof, a support bracket adapted to be fastened to said support surface, said bracket including a split housing for receiving said end cap therein comprised of a semi-circular portion integral with said bracket and a complementary semi-circular portion, and means for fastening said semi-circular housing portions together in encircling engagement on said end cap.
3. The apparatus of claim 2 which includes means for firmly supporting the tubular collector member in operating position spaced above the support surface and parallel with said tubular collector member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA345,125A CA1104016A (en) | 1976-11-01 | 1980-02-05 | Modular tubular solar energy collector apparatus |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/737,364 US4120285A (en) | 1976-11-01 | 1976-11-01 | Modular tubular solar energy collector apparatus |
| US737,364 | 1976-11-01 | ||
| CA289,151A CA1086590A (en) | 1976-11-01 | 1977-10-20 | Modular tubular solar energy collector apparatus |
| CA345,125A CA1104016A (en) | 1976-11-01 | 1980-02-05 | Modular tubular solar energy collector apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1104016A true CA1104016A (en) | 1981-06-30 |
Family
ID=27165334
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA345,125A Expired CA1104016A (en) | 1976-11-01 | 1980-02-05 | Modular tubular solar energy collector apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1104016A (en) |
-
1980
- 1980-02-05 CA CA345,125A patent/CA1104016A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |