Note: Descriptions are shown in the official language in which they were submitted.
1~)99606
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MODULAR TUBU~R SO~AR ENERGy
COLLECTOR A~PAP~TUS _ . '.
The present invention relates to apparatus for collec~ion
of solar radiation energy and transmittal of that energy as
I' heat in a liquid media for purposes of utilization in an energy
consumption system
¦, BACKGROU~D OF THE INVE~TION
Efficient collectors of.tubular variety are disclosed in
li. U. S. Patent ~o.. 3,952,724 and commonly owned .
¦~ and U.S. Patent No. 4,033,327, both ¦
j setting forth inventions of Y. K. Pei in modern, advanced.solar
¦, collector design. The prior collectors just referred to ..
i' utilize, for the st part, a liquid media to absorb and trans- ¦
t' mit energy as heat collected on a tubular solax absorbing surfac~
¦' of a collector, The liquid is handled in a manifold for series
i~. flow distribution thereof into the interior chamber of a series
of absorber tubes To maintain t~e circuit leakproof, the
; collectors are sealed in the manifold and end pressure on the
tube is provided in the structural support to bias the internal i
~ uid pressure in the interior chamber of the absorber tube as
i arise at operating temperatures of the system. The collectors.
li are constructed.from glass tubing components and have an
annular vacuum jacket between the outside tube wall and the
inside, absorber tube wall. The liquid is freely introduced
from the manifold into the absorber tube in-terior by a delivery
2S tube circuit from which the liquid flows within the confines of
the absorber tube body to the manifold. Breakage of the
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tubular collector, and in particular, breakage of the absorber
tube; or unseating and leakage of one of the collector tubes
from the manifold causes leakage or spillage of liquid and a
resulting malfunction, or, at best, loss of efficient operation
of one module segment of the system.
SUMMARY OF THE INVENTION
An aspect of the present teachings is to provide an
improved advanced solar collection system in which a liquid heat
exchange media is completely contained and circulated in a
closed tubing circuit to and through the tubular glass collec-
tors.
An important aspect is the elimination of water tight
seals on the end of the collector tube in the manifold without
loss of fluid should leakage or breakage of the collector tube
occur. Also, the system is capable of much higher operating
pressure and temperature operation.
Another important feature is in the reduction of
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.
Thus, in accordance with the present teachings,
there is provided a manifold apparatus for plural tubular solar
energy collectors which comprises a complementary pair of
elongated manifold members each comprised of a cellular
insulating material and having a cavity means defined therein,
the pairs of thè~members when juxtaposed in assemhled position
form a central cavity with a plurality of apertures
extending laterally into the manifold for receiving the
tubular solar collectors in an external laterally dependent
relationship therewith, and a tube receiving cavity comprised
of segments extending transversely and longitudinally along
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the manifold, the tube receiving cavity having each of its
transversely extending segments aligned with and extending into
an aperture of the manifold.
The basic structure of the collector tube of the
invention consists in an elongated, aouble-wall glass tube
that is closed at the one outer end and is open at the other
end. The surface of the inner wall of the tube is covered with an
absorption coating, preferably a wave length selective coating
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! having the properties of high absorption and low emissivity.
The walls are separated by an annular vacuum chamber to reduce
conduction and convection loss. The liquid is completely con-
~I tained in manifold and U-tubing as part of the closed circuit
li and the U-tube portion is inserted into the interior chamber of
the absorber tube wall of the collector. The tubular collector
¦! is connected at its open end onto the ~anifold such that the
. '~ interior chamber of the absorber tube in the collector is
' closed, such as by means of the manifold matrix. The liquid
o l! circulation system comprised of the U-tubing resides in a
.
I! stagnant, or non-turbulent air space inside the collector and
.!' the radiant solar energy absorbed on the coating of the inner
; wall of the collector is transmitted as heat through radiation, !
¦, conduction and natural convection transfer to the U-tube and
I; the liquid circulated therein.
! The in~ention also includes a split manifold member formed
of a low density insulation body and a dense, non-porous and
durable exterior skin. The manifold member supports and
encloses the liquid closed circuit connected as a serpentine
~' of tubing including several U-tubes in collectors and closure
¦` for the open end of the collector tubes. The serpentine tubing ¦
! is connected to an internal, enclosed header pipe circuit for
. handling the incoming and outgoing liquid in the system me
'; manifold in the preferred embodiment herein disclosed includes
integral support and mounting standards made as a part of the
durable exterior skin covering for mounting the apparatus.
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A further feature of the inven.ion includes the modular
i mounting of the collectors on a frame incorporating into a
modular unit the necessary elements o~ the collector, manifold
I (including the closed tubing circuit), reflector means and
¦' supports, The modular construction provLded by the invention
enables ground erection of a single module or in series grouping
o modules on a framework ready for hoisting to the place of
¦l installation at a desired solar exposure. Installations are
¦~ most prevalent atop of buildings or at elevated locations, and
~ 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
Il 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. If a glass
¦~ collector tube is broken in service, it can be replaced without
in,errupting flow of the liquid or without any loss or spillage
' of the liquid; i. e. the system need not be shut down. The only ¦
20 j loss in the system should a tube be broken would be a performance~
;~, efficiency drop proportionate to the tube or tubes out of ser-
,; vice.
As will be apparent, other objects and advantages will
undoubtedly occur to persons skilled in the art from the
~ollowing descr~ption and th2 accompanying drawings.
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, BRIEF DESCRIPTION OF THE DRAWI~IGS 2
1, FIG 1 is a perspective view, part~y broXen away, of the
¦. modular unit of improved solar energy collec~ors of the inven- i
! tion;
S ¦~ FIG. 2 is a side elevational view, partly broken away,
showing the modular unit of collectors of Fig. 1 installed on -
j the structural moaular frame installed at a site exposed to
li solar radiation.
li FIG. 3 is an exploded perspective view, in part, of one
1I modular unit of the apparatus o~ the invention;
li FIG. 4 is a sectional end elevational view taken along
Il line 4-4 on Fig. l;
¦~ FIG. 5 is an enlarged perspective view of the connector
,, for the serpentine formation of tubing and one of the manifold
15 ¦! header pipes;
, ~IG, 6 is a side elevational view, partly in section, of
the connector taken along line 6-6 on Fig. 5;
¦I 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 of the invention;
FIG. 9 is an end view of the U-~ube shown on Fig. 8;
. FIG. 10 is a side elevational view of a liquid U-tube
conduit illustrating a further embodiment of the invention in
. which the U-tube is twisted to lie in a plane near its one end
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that is disposed 90 degrees in relation to the plane at its
, other end;
, ~IG. 11 is an end view of the U-tube shown on Fig. 10i j
j, and
!~ ~IG. 12 is a perspective view of the twisted u-tube
¦~ embodiment shown on Figs. 10 and 11.
~' . DESCRIPTION ~ . .
FIG. 1 illustrates an example of the solar energy
apparatus module installed on a frame support surface 10, such
~ as the roof or a solar exposed wall of a building. The surface
' lO should be located with best exposure to the sun, such as a
southern exposure in the Northern Hemisphere, etc.. .
1, A planar diffuse reflector 11 is positioned on top of the
jl ~ramework lO and the solar collector module is mounted over the
l~ support 10 and re~lector sur~ace 11 and spaced above the upper
jl surface of the latter a prescribed amount to enhance diffuse
¦, reflection of the sun's rays. The planar reflector 11 is like
' that disclosed in commonly owned, U.S. Patent
¦ No. 4,002,162. Alternatively, shaped reflectors of the
~ type disclosed in commonly owned, U.S. Patent No. 4,091,769
¦ may be employed in combination with the tubular collector
elements hereof.
The module consists of the mani~old assembly 12 and the
pluralit~ of tub~lar solar collector elements 13 which depend
' laterally from either side of manifold 12. The outer
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depending closed ends of collector elements 13 are held in an
end support assembly 14 on an upstanding bracket 15 bolted at
16 onto the structural beams 76. For ease of illustration only
, one end support assembly 14 is shown, however, it is understood
S l, that each of the collector elements 13 is similarly mounted.
, The bracket 15 is pre~erably an integral piece spanning one
i side of the manifold for end support of all collector elements
! 13 depending along that side.
, The manifold 12 is firmly fastened to the support frame
j by a pair of downwardly depending feet 33 (to be described later
' herein) of the manifold which are bolted onto the modular
!~ beams 76.
' THE COLLECTOR
1' The collector element 13 is best described with reference
1~, to Fig. 4. An outer transparent glass cover tube 18 has a
!~ conically tapered outer end 19 and has a normally open
~' opposite end 20. The glass wall of end 20 is annularly fused
¦', to the wall of the open ena 21 of the smaller, inwardly
Il disposed glass absorber tube 22 Tube 22 is formed prior to
ii fabrication as an absorber of solar radiation energy by virtue
of a surface layer of a wave length selective coating possess-
ing properties o~ high absorption and 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.~.
of tube 22 is, for example, on the order of 2 inches.
, Preferably, this
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absorbiny coating layer is on the exterior surface of the glass
i 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 hard vacuum and shown tipped off in conventional
ll manner after the vacuum is drawn The vacuum in the space 24
eliminates convection and conduction heat loss of solar energy
- that is absorbed on the coating surface of tube 22.
I To convey the energy absorbed on tube 22 as heat from the
¦' collector element and into use in a system to which the
i collector apparatus may be incorporated, the invention employs
. I ~ bent, elongated U-tube 26 of relatively small OD ton the
¦ order of 3/8 or 1/2 inch diameter) which is inserted inside the ¦
, larger diameter internal chamber 27 o~ absorber tube 22 (I.D.
I of about 1-1/2 inches). The remaining area inside chamber 27
I is a dead air space, or may be filled with any other gaseous
heat transfer media selected for its properties in transfer o~
heat from the glass absorber tube wall to the surface of the
U-tube 26. Air is a suitable example of such gaseous media.
l~ The U-tube 26 is preferably of ductile material which is
1, preferably capable of withstandiny high pressure and high
¦'~ temperature operating conditions and which may be readily bent
. to a rather sharp reverse bend 26C prescribing the one
.,! longitudinal extremity of tube 26. From the bend at the one
l end 26C, the two elongated side-by~side reaches 26A and 26B
' of the tubing extend to the open end of the absorber tube out-
side the end o~ the double-~alled tubular collector element 13. ,
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, Depending upon direction of flow induced in tube 26, the ex-
tremities of portions 26A and 26B provide the inlet and outlet
for fluid circulation along the length of absorber tube 22.
¦', As will presently be described, the tubing 26 may be integral
1~ and contiguous, throughout, but at least must provide a con-
~i tin40us conduit for flow o a liquid heat excnanye medium, for
example, water, through certain successive elements 13 along
the manifold 12. In the examplc given on the drawings, flow of
I the liquid in the system enters the collector element 13 at one I
~ end of leg 26B and exits at the end of leg 26A (Fig. 3).
! The heat transfer in the collector element includes three
¦l, mechanisms: (1) a radiant heat transfer from the inside of
I the glass absorber tube to the U-tube 26, (2) conduction through
¦ the stagnant air space which exists between the U-tube and the
I absorber tube, and (3) natural convection which may be present
within the absorber tube The radiation heat transfer is the
dominant factor. Conduction through the gas film (stagnant
air) is the second most important heat transfer, and assuming
¦¦ the tube legs 26A and 26B are disposed in horizontal side-by-
j~ side mode (as shown) convection is of minor importance I~
' the tube 26 is positioned such that the tube legs 26A and 26B
i! are positioned in vertical mode (Figs~ 10-12), natural convec-
i tion will contribute significantly to the heat transfer In
;
~ the horizontal mode, as illustrated on Figs. 8 and 9 herein,
~ natural convection will be essentially of negligible amount.
I Angular disposition of the U-tube between vertical and
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¦ horizontal extremes will increase convection heat transfer
!, i
l~i directly in proportion to the increase in the angle from
'I }lorizontal to vertical~ ~
Il Considering radiation heat transfer as the most dominant
! factor, the U-tube should be made non-reflecting, which is
! accomplished by pro~iding an opaque blackened outer surface
¦, on the U-tube to enhance its absorbitivity. The blackeDed
j, layer on tube 26 may be a metal oxide layer, such as copper
¦l oxide, nickel oxide, zinc oxide or lron oxiae, to name a few
' examples.
i The preferred example of the invention is a copper tubing
j~ that is bent to U-tube 26 configuration and coated exteriorly
i~ with an opaque blacX oxide material to provide the non-
', reflecting property.
¦, As is apparent from the structure on Fig. 4, the open
end of absorber tube 22 is closed from ambient atmosphere by
~i the fit o the collector tube at this end into manifold 12
¦~' at the aperture 29 therein pr~vided.
i! The collector just described performs favorably with
~¦ the prior li~uid filled collectors. Based on experiments, the
collector of the present invention is very similar in per- ¦
" formance efficiency to the tubular collector utilizing
, unconfined liquid (water) circulation throughout the interior
I chamber of absorber tube. The following is an example of
performance in which the tubular collector 13 of this invention,
was simultaneously tested-with a collector tube, similarly
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' constructed, but in ~hich the water was introduced into the
, interior of the absorber tube thereof by an open ended
j, delivery tube filling the chamber of the absorber tube and
i allowed to flow along the absorber tube and out its open end
l into a manifold, such as the construction described in the
ii commonly owned U.S. Patent No. 4,018,215.
'I TABLB 1
j Staqnant Air Tube Water Filled Tube
10 ;¦Insolation Heat Heat
!~ Rate Water Collected Collected
jBTU/hr.Ft.2 ~remP. BTU/hr. Efficiency BTU/hr. Efficiency j
72 122~F 50.7 52,3% 50.7 52.3%
150 48.6 50.2 55.4 57.2
li 173 45.7 ~7.2 38.1 39.3
! 114 122~F 84.1 56.3% 75.1 49.0%
150 76.2 ~9 7- 74 0 47 4
t 173 72.6 47.7 72.8 47.5
1! Overall average 50.6% 48.9%
il Insofar as the U-tube is concerned, its composition may
1I be varied depending upon operating conditions for which the
solar collector apparatus is designed. The structure of this
invention, just described, enables a wide range of operating
! conditions oE the collector, viz high pressure and high
1 temperature conditions in the closed and confined heat exchange
' liquid system. Under these high temperature, high pressure
' conditions, the liquid confined in the syste~ including the
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¦ U-tubes and header pipes are capable oE operatin~ pressures up
to 1600 PSI and to temperatures to the o~der of 600F. There-
¦ fore, the U-tube may be constructed of most metals including
! copper, brass, steel or steel alloys, stainless steel,
1, aluminum, to name the more common metal compositions. Also
! the U-tube may be made of glass which possesses good inert
I! properties in handling a heat exchange liquid, such as water.
The preferred construction of the tubing serpentine and
Il header pipes is steel tubing, principally for the sake of
10 !, strength and cost. Copper tubing, as earlier indicated, is
1l also a ver~ satisfactory material for this part of the
!l aPparatus,
, The tubing system of the apparatus provides a shortened
~i residence time in the collectors and provides the benefit or
1! better control in the overall system for 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
',' of common ownership, utilizes 9 gallons o~ water in a twenty- ¦
~ four tube collector module. The present invention constructed
l~ with 3/8" aiameter tubing of the same size module holds 1.5
¦~ gallons of liquid in the serpentine tubln~ plus 0.33 gallon
in the 1" diameter header pipes. For flow rate of 0.3 gallon
1 per minute, the residence time of the liquid in such module
! i
, is reduced from 30 minutes in the prior liquid-filled collector
~ system to 3.6 minutes in the present invention.
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Under certain lower pressuxe/tempQra~ure operations, the
U-tube may also be made of rigid plastics in common use today,
however, care in selection of these must be taken because o~ j
1 the possibility of failure or rupture under too high pressure
5 IJ or temperature conditions in the liquid circulated through the
! U-tube.
¦~ To reduce radiation loss to a minimum in the U-tube, any o~
¦¦ the materials suggested may be surface coated or clad by known
¦~ technic~ues to provide a blacXened, non-reflective coating on
¦~ the U-tube, at least over that portion of the U-tube contained
¦¦ within the collector element 13.
¦~ Accordingly, without sacri ice of performance ef iciency,
¦~ under the present invention the advantages alluded to herein
¦l are practicall~ obtainable.
lS ~l In the description of the invention herein and illustrated
¦l on the drawings, the U-tube structure is integrally constructed f
!~ for a series of the tubular collectors 13 in a module for the
l~ saXe of convenience. However, the serpentine U-tube series
¦' may be constructed of pieces of tubing connected together, and
1~ certain portions thereof may be maae of dif~erent materials of
¦~ sufficient strength to reduce cost in construction of the in-
! vention. For example, each of the U-tubes in the collector may
!' I
be fabricated of copper tubing, as indicated, and these
~ connected together into the serpentine series, as illustrated,
i by tubing of a different, lower cost material. In this regard,
certain combinations of materials to achieve cost effectiveness
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of the system are well ~ithin the skill of artisans in this
field.
Similarly, materials may be ~elected in fabrication of
the header pipes of the modules, described above, for cost
jl efectiveness in a given set of operating conditions Since
~; the preferred examples are described using water as the heat
exchange liquid media in the collector elements, steel or
copper have been selected for ease of fabrication or corrosion
!I resistance or protection against electrolytic effect in the
¦ system. The invention is not limited to such materials,
jl however. The one advantage of the invention must be observed.
i' The liquid is confined in the solar collector apparatus for
¦1 flow between the p~int of collection of the ener~y in the
¦~ sy~tem and to a transfex point in the part of the system in
~I which the energy is either utilized or stored.
~' THE MANIFOLD
` As best shown on Fig. 3, the manifold 12 is comprised o~ j
complementary upper and lower half sections 30 and 31,
1, respectively, of modular length. Each of sections 30 and 31
¦l are preferably molded in the following fashion. A sheet
molding compound (SMC) in sheet form is first draped over the
mold cavity and heated to a pliable, softened consistency.
The SMC is then pressed into the cavity of the mold setting
the exterior skin layer 32 of each piece. The SMC material is
one that is com~ercially available from several manufacturers,
such as ~. R~ Grace Company and ~ens-Corning Fiber~las
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Corpora~i~n. Such material is comprised oE a polyester com-
position that is reinforced with imbedded fibers or strands of
glass (fiberglass) The polyester is a thermosetting plastic
! compound. After the S2~1C skin layer is shaped in the mold
1! cavity, it is cured under sufficient temperature, well known
¦~ in the art, for a time (such as 20-30 seconds) to render the
thermosetting plastic rigid. The result is the exterior skin
! layer 32, represented specifically on Fig. 4, which forms a
1, durable, dense, non-porous exterior covering for the manifold~
j. ~ny desired pigmentation or color may be blended into the SMC
material for an attractive appearance of the maniold. At the
time of molding sXin 32, just described, the cavity of the mold ¦
, 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 of lower half section 31. Thus, the underside
j support brackets for each modular manifold length are made
I! integral with skin layer 32 and from the same rein~orced thermo-
setting material.
1~ After the SMC material is molded to shape and cured in
!I the mold, the shell of the skin 32 provides a cavity into
¦ which is molded a matrix of low density thermal insulating
~' material, such as foamed polyurethane of 4-6 lbs. per cubic
,' foot density. The foamed polyurethane material is placed in
! the hollow interior of the shape formed as sXin 32 and molded
~ to a contour by known technique, such as by a die platten
having cores and channels, for shaping the interior cavity
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! portions of the modular manifold sections 30 and 31. As seen
; on Fig. 3, the insulation material is molded to shape two
1 side-by-side, longitudinally extending channels 34 and 35 in.
f~ lower section 31 for receiving two header pipes 36 and 37,
~' respectively. At the lateral outside edges of channPls 34 and
¦, 35 there are two smaller, spaced-apart, lateral, parallel
li channels 38 and 39 of approximately semi-circular configura-
! tion through each end wall 40 o~ the recessed semi-circular
¦. cavity wall 41 formed in the insulation and skin layer 32.
~ There are several of these shaped cavity walls 41, 40 along
. each longitudinai side of manifold 12 for receiving the open
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¦~ end of a double-walled glass collector tube 13. The spaced,
i parallel, lateral channels 38 and 39 in each collector tube .
! aperture wall are provided in complementary matching fashion
¦, in both the upper and lower manifold sections 30, 31 so that,
i in a juxtaposed relationship of the sections, the channels 38,
,, 39 will receive and surround the legs 26A and 26B, respec-
¦' tively, of U-tube 26.
1, In the formation of skin layer 32, there is also formed
1~ a semi-circular flange 42 having a gasket receiving groove 43
'~ formed thexeby around the edge of the collector- ube receiving
. aperture. A circular rubber grommet 44 is seated in ~he com-
bined upper and lower semi-circular grooves 43 which retain the
I annular gasXet 44 ~hen the sections 30, 31 are juxtapositioned
in their assembly (such as shown at the right-hand side of
Fig. 3). The upper half section 30 is fastened to the lower
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half section 31 by a horseshoe st~le of U-clamp ~5 comprised
of the thermosetting polyester material ~o match the skin 32.
Clamp 45 has some resiliency and is forced over the upper half
' section 30 at opposite ends of the module length thereof.
I, Lateral, spaced apart exterior ribs 46 are formed integral on
j skin 32 at the ends of section 30. The ribs 46 of adiacent
¦, manifold module lengths receive a clamp a5 to locate it with
i stability and guide it to its seat on the lower section 31
¦I which is comprised of integral exterior lugs 47 on the skin
¦~ la~er 32 thereof. As shown at the right side of Fig. 3, one
., lug 47 is in circumferential alignment with its opposite rib
¦, 46 at each end o~ section 31 and the inner facing, spaced cam
jl lugs 48 on each of the dependiny ends of horseshoe clamp 45
' snap over a lug 47 This snap fit holds the top section 30
1l onto lower section 31 closing the manifold about the header
¦~ tubes 36 and 37 and the U-tube serpentine comprised of the
', series of UT-tubes 26 and lengths of tubing 26D interconnecting
one U-tube to the next. The downwardly depending spaced edges
, 49 of clamp 45 fit along the opposite outside edges of the ribs
¦ 46 o~ ad~acent mani~old lengths and clamp the two toge~her in
i end-to-end abutting attachment.
~' The tu~e serpentine formation tthe series of U-tubes 26
,' and intermediate lengths 26D connecting them together) is made
~ 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 pockets 41 for the collector tubes 13 along one
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side of the maniEold. These tube pockets are defined by the
walls 40, 41 inwardly of the grommet flange 4~ in each of the
!;
i modular lengths of the manifold, as described earlier. T'ne
!~ forward (inlet) end of the left side serpentine of the manifold
j~ is connected to threa2s 50A of a connector bloc~ 50 on header
¦, pipe 36 (Fig. 5) b~ a flared, thrèaded pressure fitting 51
ll (phantom outline on Fig. 7). Connector block 50 has a curved,
! contoured lower face and is welded onto ,he periphery of inlet
Ij header pipe 36 to align the radial passage 52 in the block with
~J a punched aperture 53 in the wall of header pipe 36. Passage
¦~ 52 for~s a T-connection with the lateral passage 54 in block
¦~ 50 and passage 5~ has the female threads 50~ in the block at
' each end thereof for fastening the threaded serpentine end
! fittings 51 and 55 respectively. The fitting 55 is the inlet
¦ end threaded fitting on the right hand serpentine (Fig. 3).
Thusly, the two serpentine tubing formations for the right and
left hand sides of the collector manifold are connected into
il the inlet header pipe 36. Similarly, the outlet ends of each
I¦ of these serpentine tubing formations are connect~d into a
¦¦ connector block 56 (constructed the same as blocX 50) which is
I welded onto outlet header pipe 37 over a punched aperture
! therein located along the manifold near its lar end. In the
!, fashion clescribed for tne inlet connection, the other terminal
i end of each of the t~o serpentine tubing formations are
! pressure-fitting connected into the-lateral passage of
~ connector block 56 which in turn is internally connectecl to
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outlet header pipe 37. The interior web 59 oE the low density
!
insulation between pip2 ch~nnels 34 and 35 rormed therein is
provided with slmilar recesses 60 ~o receive the bloc~ f
~ connectors 50 and 56, respectively, adjacent opposite ends o~
5 !~ the module.
¦~ Any number of the manifold module lengths may be connected
!~ end-to-end by the pipe couplers 57 and 58 for connecting the
! far end of the inlet heaaer pipe 36 and outlet header pipe 37
¦~ respectively, to the near end of the same elements 36, 37
10 ji (superimposed in phantom outline at the right-hand side of
¦, Fig. 3) in the next module o~ the manifold. ~n the far end of
¦I the last module in an installation, end caps (not shown) replace f
the pipe couplers S~ and 58. With the just described connec- f
1 tions made, the manifold sections 30, 31 are closed along an
1~ overlapping seam line 120 (Fig. 2). Each of the serpentine
¦ tubing formations is now connected to the inlet header pipe 36 f
i at one end and to the outlet header pipe 37 at the other end. I
¦l A liquid heat exchange media supply ln the system installed for ¦
j, utilization o collected solar energy may be connected, as the
¦~ inlet to the collector at the pipe 36. A suitable liquid for
! this purpose is water, which has a high specific heat. By
forcing flow of the liquid in the system, suc'n as by a power
driven pump, the liquid is introduced by the inlet header pipe
i 36 into each of the tubing serpentines o~ the system for flow
i successively through each of the U-tubes 26 in th~ collectors 5
j 13 disposed along one 5 ide of each module. By exchange of the
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j solar energy collected by the tubular collectors 13 as heat to
.~ the li~uid in the close~ tubing 26, the eneryy is carried from
!~ each oE the serpentines into the outlet header pipe 37, which
Il is in turn connected into the system receiving the energy.
j, The pipes 36 and 37 are held in a block 61 (Fig. 3) o~
¦l insulation material and a formed end cap 62 is fastened onto
¦, the one end face 63 of the assembled manifold. A suitable
~! assembly of end cap 62 is by an RTV, silicone rubber adhesive
¦~ which cures at room temperature. Such adhesives are commer-
10 i. cially available. End cap 62 is made the same as the sections
¦l 30, 31 in that an SMC material is molded as the high density
~' outer skin (32) thereo and a low density core o~ the foamed
', polyurethane insulation material is formed to a shape inside
~ this skin or shell. An appropriate recess 61A (shown by
15 ¦¦ dotted outline) in the body of the end cap is molded tff receive
insulator blocX 61 and the bend portions of pipes 36 and 37.
Suitable insulation about the pipes 36, 37 emanating below S
j end cap 62, such as shown at 68 on Fig. 2, will of course be ¦ -
¦ provided to avoid unnecessary heat loss in the circulation o~
20 1, liquid through the system.
¦ As best shown on Figs. 2 and 4, the several tubular
collectors 13 asse~bled as earlier described herein are in-
! serted over the U-tubes 26 depending outwardly from the
maniold aperture at flange 42. The open end of tube 13 butts
25 1 against the insulation wall 40 at the back of the tube
pocXet 29 in the manifold and by this means substantially
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closes the open end of the collector tube. The atmosphere
inside the tube is enclosed and is non-turbulent (dead air
space). This provides the media to transfer energy (heat)
~ absorbed on the coating of tube 22 inside the collect~r
! chamber 27 to the U-tube 26 and in turn to the liquid circu-
lated therein. The double wall sectian (18,22) at the end
~l of each collector tube 13 is insexted within the manifold
pocXet such that the grommet gas~et 44 annularly engages the
Il outer surface of cover tube 18 in a cross-sectional area of
j, the double-wall tube that includes the annular vacuum
¦ chamber 24 formed by the two glass wal~s tl8, 22). This is
¦ important to prevent heat loss by the collector through con-
¦ duction and convection, i.e. a vacuum jacketed, insulated
1 part of the collector tube 13 is inside the grommet 44 in the
l' manifold aperture pocket and sealed by the gasket 44.
¦, 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
j' preferably tapered to a substantially`conical shape that in-
i cludes tubulation 25 through which the vacuum is pulled to
evacuate the annular chamber 27 between the tube walls 18 and
22. ~here is a plastic end fitment 65 (Fig. 4) placed over
the end of the sealed tube on glass end portion 19 thereof
, which protects the glass surace from abrasion, scratching and
abuse in service. This fitment includes the series of in-
wardly facing ~nnular ribs 66 engaging the glass. The open,
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large end of fitment 65 includes an annular, outwardly project-
ing, ring-like end enlargement 67 of the fitment. The bullet-
'. shaped outer end cap 14 is made in split configuration and
, cncircles the end fitment 65 engaging the latter securely so
5 il as to somewhat compress the ring-liXe por~ion 67 of the fitment
, annularly against the glass surface of cover tube 18. The end
cap 14 is held in the engagement just described on the end
bracket 15 in the following manner. Bracket 15 is com~rised
i, of its upstanding legs 71 at either longitudinal end thereof. .
ll The lower ena oE leg 71 is bolted onto the beams 76 of the
i, modular frame (to be presently described) by a pair of lower
,- bolts 16. Spanning between the legs 71 at either end of the
! bracket there is an integral lower ~eb section 69 including the
¦, spaced-apart, semi-circul~r halves of the end cap. The axial
,,l centers of the end caps are coaxially located with respect to
! the centers of the respective installed collector tubes
i supported by the manifold. First the collector tubes inserted
.over tubes 26 and in the manifold pockets 29 rest in place on
!, the lower section of the truncated outer caps 14. ~ext, an
1', upper, retainer member 73 is placed onto the matching top lip
. 72 of section 69. The retainer member 73 includes corresponding¦
semi-circular truncated halves which match with the semi- I
; circular lower halves and together form the end cap 14 for f
each collector tube 13, The retainer me~ber 73 is securely
fastened at the ends onto the legs 71 and section 69 by cap
~ screws 75. The assembled end bracket 15 and the encircling
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end caps 1~ hold each collec~or tube firmly in position. In
the present invention, there is no requirement for the end cap
to provide an axial com~ression load on the collector tube to
1 rctain it in the manifold, there being no internal pressure
!~ applied inside the absorber tube chamber 27 to tend to force
' the collector tube axially out of the mani~old Accordingly,
the force placed on the end of the collector tube by the end
" mounting, jus~ described, need only be sufficient to firmly
¦, support the tube against vibration as may be caused by exterior
¦ forces, such as wind and weather.
' MODU~R ASSEI`~BLY
,' The manifold 12, collectors 13 and end bracket supports 15
are incorporated into a modular assembly, as shown on Figs. 1-4.
j A pair of cross beams 76 of structural material, such ~s steel
lS j, or aluminum, are placed parallel and manifold lower section 31
is bolted in place on the flange o the beams by studs 33A
molded into legs 33. These beams 76 are preferably selected
according to the following. The end module of an installation
1, includes an L-shaped beam at one end. Intermedia~e modules are
~, constructed with a T-shaped beam having the wider web at the
top thereof. Adjacent module assemblies have the manifold legs
33 bolted onto the same web of the T-beam. Similarly, the end
bracX~t 15 has its legs 71 bolted to the top web spaced beams
, 76. The reflector sheet 11 is installed on the frame work 10,
~ such as the roof of a building. Over sheet 11 there are two
U-shape~ brackets 70 each fastened by a scre-~ 74 through the
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reflector. The brackets 70 are installed as pairs aligned to
receive each of the beams 76 ancl support them in parallel
, fashion.
' As seen on Figs. 1, 2 and 4, each bracket 70 has a slot 77
S j in the upright sides thereof whicb receives a pin 78. Pin 78
,'' is inserted through a hole provided in the proper location on -
~' the vertical section of the beams 76. Thus, the modular units
! f the apparatus after assembly over the beams 76 are hoisted
! to the brackets 70 and supported by the pins 78 fitted into
the proper slots 77 of the U-brackets 70.
This construction permits ground site assembl~ of all of
the parts of a module assembly of the solar collector
I~ .
I; appara.tus. This assembled module may then be hoisted into
!~ place on a solar exposure site of a building or framework and
1i there fastened into place. Of course, the liquid connections
i~ to the header pipes 36 and 37 will be made after the module
I or modules are located in place and fastened together. Thus,
¦, the system is connected ~or circulation of the liquid through
~, the several serpentines of tubing by flow between the inlet and ¦
,' outlet header plpes. The flow rate of the liquid on the
~ installation framework (or building) will be limited to the
j volume of the header pipes and the serpentine tubing o the
particular installation. This volume is less in weight than
'~ the liquid collectors utilized heretofore in which liquid flow
through the system filled the absorber tubes and manifolding at
all times. Moreover, breakage of a tube collector of the module
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will not result in loss of liquid or malfunction of the module.
, Since the liquid is confined in this serpentin2 tubing circuit
! i
i and the header pipes, the loss of liquid or potential damage
; ' i
by spilled liquid is obviated.
5 lll Also, the closed system for liquid in the present inven-
1~ tion permits design o~ very high pressure units -- up to
'. 3000 PSI -- and at very high temperatures -- in the area of
li 1600F -- enabling use of the solar collector apparatus in
¦; power generating applications.
,, SECOND EI~BODIMENT
! ~s shown on Figs. 10-12, the serpentine array of tubing
260 may be constructed such that the depending legs 261 and
262 depend ou~wardly from the connector section o~ tubing 263
,j in an over and under relationship. The reverse, U-bend portion j
¦, 264 of the tubing at the far end of each U-tube is twisted,
;~ that is, the section 263 at one end lies in a pl~ne 90 degrees
from the plane at the bend 264. Thus the serpentine of tubing
which, in the first embodiment, lay principally along one
~ plane, this serpentine construction has the U-tube bent into
~ two planes at-right angles to each other (see h'ig. 12).
This form of the invention has advantages in providing a
fall or drop for the liquid in the U-tubes for draining them
i if desired. The performance and efficiency of the cdllector
, remains about the same as in the first embodiment. The
assembly of the tubing serpentine into the ylass, double-t~all
tube collectors 13 is the same as before. The cut-outs in
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the manifold matrix (best seen at 38, 39 on Fig. 3) utilized
: in the first emb~diment may need to be revised to corresp~nd
with this modification Essentially, the balance of the
~ apparatus of the invention des~ribed earlier herein remains
j~ the same.
! The module concept herein described and included in the
!~ preferred embodiment, utilizes tubular solar energy collectors
j~ depending from both longitudinal sides of the manifold. It
1 is also within the scope or the invention to arrange the
!' manifold such that the collectors depend along but one side
¦ thereoE. Further, the mani~old may be structured under this
1~ invention to a form other than a straight, elongated figure,
¦l should a particular solar exposure structure or installation
¦l be better suited to a modi~ication of this style.
i~ , . .
I' Other and further modifications may likewise be resorted
! to without departing from the spirit and scope of the appended
i,'
I claims.
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