Solar heating module

A combination solar collector, thermal storage and heating module for mounting in a building framework comprising a hollow panel member for receiving a thermal storage mass, including an outer wall and an inner wall; opposed pairs of sidewalls and end walls sealed to the inner and outer walls for connecting the corresponding perimeters of the inner and outer walls, thereby defining an enclosed chamber; a plurality of individual connections each of the connections forming a joint between the inner wall and the outer wall for maintaining the rigidity of the walls when the chamber is filled with the mass; and a port in the panel member for filling the panel member with the mass. Various modifications and alternatives are disclosed including several structures for attaching the module to the building framework, and additional modifications for increasing solar absorption and decreasing heat loss from the building.

FIELD OF INVENTION 
This invention relates to solar heating devices, and more specifically to a 
device for mounting in a framework of a building for collecting and 
storing heat from the sun, and dissipating that heat into the interior of 
the building. Such devices may also be utilized in reverse for cooling a 
building. 
BACKGROUND OF THE INVENTION 
Efforts have been underway for many years to develop improved apparatus and 
techniques for the passive heating and cooling of buildings and other 
structures. Passive solar heating and cooling generally involve a transfer 
of energy by radiation through a panel into a thermal mass or fluid. In 
heating applications, solar energy is normally stored in the thermal mass 
and is then radiated into a building or other structure for heating the 
interior thereof. 
A large number of different solar heating devices have been developed in 
the prior art. Although earlier designs in solar heating devices generally 
required exterior mounting on the roof of a building or structure, more 
recent designs have placed emphasis on devices which can be installed 
directly in the walls of a building. However, such devices have not been 
readily accepted commercially by builders and other developers because of 
their high cost, the difficulty of incorporating such devices into 
standard housing plans, and the adverse visual and aesthetic impact on the 
overall house design perceived by the majority of home buyers. 
Accordingly, it is a primary object of this invention to provide a solar 
heating module which is economical to manufacture and install. 
It is a further object of this invention to provide a solar heating module 
which is readily adaptable to installation in buildings of standard design 
between building studs or rough wall openings, as is the practice with 
conventional windows. 
Another object of the invention is to provide a prepackaged solar heating 
unit with glazing attached, which may be easily installed by a builder. 
Another object of the invention is to provide a solar heating module which 
may be installed directly in the frame of a building without significantly 
modifying the aesthetic lines of the building. 
An additional object of the invention is to provide a solar heating module 
which can be easily installed in a building frame, including a thermal 
mass storage member and the glazing sheet which may be separately attached 
or detached from the building frame. 
Additional objects and advantages of the invention will be set forth in 
part in the description which follows, and in part will be obvious from 
the description, or may be learned by practice of the invention. The 
objects and advantages of the invention may be realized and obtained by 
means of the instrumentalities and combinations particularly pointed out 
in the appended claims. 
SUMMARY OF THE INVENTION 
To achieve the foregoing objects and in accordance with the purpose of the 
invention, as embodied and broadly described herein, the solar heating 
module of this invention comprises a hollow panel member for receiving a 
thermal storage mass, the panel member including an outer wall and an 
inner wall; wall joining means for connecting the corresponding perimeters 
of the inner and outer walls, thereby defining an enclosed chamber; 
tensile means between the inner and outer walls for maintaining the 
rigidity of the walls when the chamber is filled with the mass; and port 
means into the panel member for filling the panel member with the mass. 
The tensile means may also serve the purpose of dividing the panel member 
into horizontal segments which limit separation of the thermal mass when 
it is a material subject to chemical separation, such as a phase change 
material, due to the small vertical cross-section of the segments. 
Preferably, the tensile means includes a plurality of connections, each of 
the connections forming a joint between the inner wall and the outer wall. 
The connections preferably define a plurality of mutually opposed pairs of 
depressions in the walls, the opposed pairs being connected or seamlessly 
molded to form the joints. These depressions also may serve as female 
attachment sockets for anchoring shelving brackets or other fasteners. 
It is also preferred that the wall joining means include opposing pairs of 
side walls and end walls sealed to the inner and outer walls. The inner 
and outer walls may be formed of translucent or transparent material, or 
may be opaque. 
It is also preferred in some embodiments that vertical ribs be integrally 
molded into the outer surface of the panel member thereby presenting an 
undulating exterior surface. This undulating surface enhances solar 
absorption by increasing the overall surface area exposed to sunlight, and 
by providing a face with a portion perpendicular to incoming sunlight at 
all times of daylight. 
Preferably, mounting means are provided for attaching the panel member into 
the frame of a building, and it is preferred that the panel members be 
oriented vertically and mounted between adjacent wall studs of the 
building, or added to the surface of interior walls which are in the line 
of sight of windows. 
Preferably, the module is light transmitting, and the outer wall may also 
include a plurality of protrusions molded onto the external surface 
thereof for increasing solar absorption while still allowing for light 
transmission through the module. 
The walls may also be tinted for increasing solar absorption by the module, 
and a decorative pattern may be integrally molded on, or attached to the 
surface of the inner wall of the module. 
The inner and outer walls, the wall joining means, and the tensile means 
are preferably integrally formed of a molded thermo-plastic material. A 
translucent glazing panel may be included for covering the outer wall, and 
additional glazing layers and convection suppressing barriers may further 
be used to enhance system operation. The glazing panel and/or the panel 
member may be separately attachable and removable from the building frame. 
The inner wall of the panel member may be covered with a decorative 
material such as a fabric of woven or open weave fibers, or a grass-type 
mat for reducing the flow of purchased back-up heat in the building into 
the module.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference will now be made in detail to the present preferred embodiments 
of the invention, examples of which are illustrated in the accompanying 
drawings. 
As shown in FIGS. 1-4, the invention is a solar heating module for mounting 
in a framework of a building. The module comprises a hollow panel member 
for receiving a thermal storage mass including an outer wall and an inner 
wall; wall joining means for connecting the corresponding perimeters of 
the inner and outer walls, thereby defining an enclosed chamber; tensile 
means between the inner and outer walls for maintaining the rigidity of 
the walls when the chamber is filled with the mass; and port means into 
the panel member for filling the panel member with the mass. 
As here embodied, the module includes a hollow panel member 10 which is 
preferably thin walled and integrally formed or unitary. The panel member 
10 has a generally rectangular outline and has two opposite face walls 12 
and 14. As here embodied, the wall joining means includes two opposite 
side walls 16 and 18 and two opposite end walls 20 and 22. When the module 
is vertically oriented, the end walls 20 and 22 constitute the top and 
bottom of the module, respectively. The panel member 10 may be formed of 
the same materials and by the same process as used to manufacture 
thermoplastic milk bottles, carboys, bulk olive jars, and the like. For 
example, the module may be blow-molded, vacuum thermoformed, slush casted, 
or rotationally molded. A typical wall thickness is 0.125 inches and 
typical overall dimensions are three feet, nine inches (3'9") tall; three 
feet, ten and one half inches (3'101/2") wide; and seven inches (7") 
thick. The seven inch preferred thickness of the module corresponds to the 
amount of water mass necessary to achieve optimal thermal benefit from the 
module of this invention in much of the United States. If phase change 
material is used, the module may be as thin as one inch. The module is 
preferably integrally formed and is seamless. 
As here embodied, the tensile means comprises a plurality of connections 24 
joining the inner and outer walls 12 and 14 of the panel member 10. 
Typically, the connections are arranged in a rectilinear pattern on 
approximately six inch centers, and each of the connections 24 forms a 
recess having a draft or taper, in the general shape of a cone. Typically, 
each recess is one inch (1") in diameter at its mouth tapering to one-half 
inch (1/2) in diameter at the center of the panel member. The connections 
24 may be continuous, forming a hollow tubular recess completely through 
the panel member 10 as shown in FIG. 7, or they may be joined at a base 
26. In addition, solid tubular members may be bonded into position between 
the walls, if desired. 
The connections 24 prevent the inner and outer walls 12 and 14 of the panel 
member 10 from centrally ballooning away from one another when the module 
is filled with a thermal mass. Instead, the connections 24 form tensile 
structures which maintain the rigidity of the walls 12 and 14. In 
addition, these connections provide compressive strength to protect 
against collapse of the walls in the event of sub-atmospheric conditions 
in the panel member. These connections also provide a cavity into which 
wall fasteners may be secured to support attachments to the panel member. 
As embodied herein, the port means includes a filler valve 28 in the panel 
member 10 as shown in FIG. 1. A suitable cap 30 is provided for sealing 
the filler valve. 
In accordance with the invention, the wall joining means includes rib means 
for expansion and contraction of the panel member in response to thermally 
induced changes in the volume of mass within the panel member. As here 
embodied, the rib means includes a pair of ribs 27, shown in FIG. 1 in the 
form of a flange extending outwardly from the side walls 16 and 18. 
Alternatively, the ribs may be isolated along a part of their length from 
the module interior. In this form, the ribs 27 may serve as nailing strips 
or as conduits for various purposes. The ribs 27 may be offset toward the 
inner wall 12 or the outer wall 14 instead of being located at the 
midline, as depicted in FIG. 1. 
In the preferred form, the ribs 27 provide a unique solution to thermal 
expansion of the panel member 10, which goes through cycles of substantial 
temperature change on a daily basis. The inherent flexibility of the 
thermoplastic material which is typically utilized for construction of the 
panel member 10 allows for expansion of the panel member 10, particularly 
at the junction of the ribs 27 and side walls 16 and 18, and at the 
junction of the side walls 16 and 18 and the inner and outer walls 12 and 
14. A combination of substantially right angles at these connections 
provides a bellows effect which permits the panel member 10 to expand and 
contract in response to the thermally induced changes in volume of the 
thermal mass. Even though the panel member 10 is firmly supported in a 
building frame, thermal expansion is permitted. 
The bellows action described above becomes more important when the thermal 
mass in the panel member 20 is a phase change material. Such materials 
have a significant thermal expansion and contraction cycle on the order of 
ten percent. The bellows action safely permits simple installation of the 
panel member 10 while providing proper relief to constant and substantial 
changes in volume of the contained medium. This solves a principal problem 
of encapsulating conventional phase change material. 
The ribs 27 may be hollow and separate from the main body of the panel 
member 10, thereby forming a tube adjacent to either side of the panel 
member. An example of integrally molded tubes extending from the bottom of 
the panel member to the top of the panel member is shown in FIG. 7 at 68. 
These tubes may include openings into the main body of contained mass at 
the top or at the bottom of the panel member 10, or in both locations. The 
tubes 78 can thus be incorporated in a thermosiphon arrangement, described 
hereinafter. Such an arrangement eliminates plumbing connections, piping 
and seals which would otherwise be required. 
The ribs 27, or portions thereof may be formed as flat solids in lieu of 
tubes to act as nailing ears for mounting the panel member 10 to 
building's framework. This feature provides a simple means of attachment, 
which may be readily adapted to roof mounting. In such a configuration, 
the module may be modified for domestic water preheating by installing an 
internal heat exchanger which may be molded integrally as a tank within a 
tank. In this case the domestic water line is fitted with a heat exchanger 
formed within the module. The module acts as a sky-light, and functions as 
a domestic water preheater. 
In FIG. 1, a building structure is depicted which includes a pair of two by 
eight walls studs 36, 40. The module 10 may be sized to fit entirely into 
the space between two adjacent studs or may protrude slightly beyond 
smaller studs such as two by fours. The overall thickness of the panel 
member 10 may be no greater than the comparable thickness dimension of the 
framing 36, 40 so that the wall 50 which incorporates the panel member 10 
can be made to completely house it by fastening a panel of transparent or 
translucent glazing 52 to the outside of the wall 50. A panel of heat 
conducting material such as sheet rock, woven cane or cloth 54 may also be 
applied to the inside of the wall 50, by attachment to wall studs or to 
fasteners in the dual purpose tensile sockets. The inside of the wall 50 
may be covered in whole or in part with a sheet of decorative material, 
such as a woven fabric for further suppressing convection. Alternatively, 
a soft fibrous material may be bonded to the inside of the wall 50. 
To permit use of modules wider than conventional stud spacing, an 
intermediate stud may pass through an appropriate groove in the module. In 
such an arrangement, either the inner wall 12 or the outer wall 14 is 
provided with a vertical medial groove 32 extending completely across the 
panel member 10. The medial groove 32 extends approximately half way 
through the thickness of the panel member 10. Preferably, this groove 32 
has a base 34 which forms the connections 24 with the opposite wall 12 or 
14. The base 34 is typically two inches wide, or at least the actual 
finish width of a two by four stud. 
The panel member 10 may be inserted into the space among three studs 36, 38 
and 40, the flanking studs 36 and 40 being finished two by eights and/or 
two by fours and the intervening stud 38 being a two by three or two by 
four. The inner or outer edge of the intervening stud 38 may be flush with 
the corresponding edges of the studs 36 and 40. The panel member 10 
straddles the stud 38 and occupies the stud space 42 between studs 36 and 
38 and the stud space 44 between studs 38 and 40. 
The vertical groove 32 functions similarly when the panel member is 
deployed horizontally in a ceiling or floor, or at any angle. The 
intermediate stud 38 may be constituted by a wooden member between two and 
one half inches and twelve inches in depth or may be a metal member of 
appropriate support dimension. The intermediate stud may be a roof rafter 
or floor joist, which may or may not extend beneath the surface of the 
panel member 10. 
In addition, when the panel member 10 is deployed in a ceiling or beneath 
the ceiling, the intermediate stud 38 may be a steel channel which 
contains electrical wiring or a lighting fixture such as a fluorescent 
tube. The light fixture hides the steel channel and provides supplementary 
lighting as needed at night. The light fixture may be covered with an 
opaque or semi-opaque cover having a reflective backing to prevent the 
light source from appearing as a hot spot of light. Such a reflective 
backing also bounces the light to the left and right of the light source 
into the thermal mass, making the panel member 10 a diffused light source 
at night. The module admits natural day light when available, and 
artificial light when desired. 
Thus, the solar heating module doubles as a night lighting source in this 
configuration. Small slots may be provided along the full length of both 
sides of groove 38 as a mounting means for the light reflecting cover 
and/or the light fixture. 
Preferably, the panel member 10 is made half the height of the wall stud 
space in which it will be installed. The panel member 10 preferably 
occupies the space above a fire stop 56, or may be installed below a fire 
stop 56. Alternatively, two panel members 10 may be used, one above and 
one below a fire stop 56. A convenient mounting technique is illustrated 
in FIG. 1. A first slightly off-center stop 58 is attached to the studs 36 
and 40. The panel member 10 is inserted into the stud space until it rests 
upon the fire stop 56. A second stop 60 is attached to the studs 36 and 
40. The ribs 27 are trapped between the respective holding the module in 
vertical orientation so that it does not exert pressure on panels 52 and 
54. Obviously, various other mounting techniques may be utilized. 
For example, the stops 58, 60, or other suitable mounting means, may be 
used to secure respective strips into the frame where the module is to be 
mounted. Each of the mounting strips includes a groove for receiving one 
of the ribs 27 in close fitting relation. This method of installation 
permits removal of the panel member 10 without the need to substantially 
disassemble other sections of the wall or disturb panel members in 
adjoining stud spaces. U-shaped channels may also be utilized for this 
purpose. 
The panel member 10 is filled with water or other thermal mass fluid and 
sealed. Where the inner or outer walls 12 and 14 are transparent or 
translucent, a conventional algecide may be added to the water, or to the 
plastic resin comprising the module. 
The entire panel member is preferably formed integrally of a thermoplastic 
material or resin. The light transmission and radiation absorption 
characteristics of the panel member are regulated, in part, by the color 
of the resin used. A transparent resin offers the highest light 
transmission while an opaque resin offers the best ultraviolet protection 
and absorption. Variations between these two extremes may be utilized to 
provide different light transmission characteristics. 
In FIGS. 5 through 9, an alternative embodiment is depicted. In this 
embodiment, a stud space 62 below the fire stop 63 is filled with a 
blanket of thermal insulation 64. A conventional freeze tolerant flat 
plate collector 66 is mounted on the exterior of the wall over the 
insulation blanket 64. A thermosiphon tube 68 extends upward through an 
opening 70 in the fire stop 63 through a circumferentially sealed opening 
72 in the end wall 22 of panel member 10. The thermosiphon tube 68 
terminates within the internal space 74 of panel member 10 near the 
opposite end wall 20. 
As described previously, the use of a hollow cavity or pipe as the side rib 
27 in FIG. 1 may serve as an alternative to the thermosiphon tube 68. A 
return line 78 extends from the lower end of the flat plate collector 
between the insulation and the adjacent stud through an opening 80 in fire 
stop 63 and into internal space 74 of the panel member 10. The return line 
78 is sealed in an opening 82 of the panel member 10. The return line 78 
terminates inside the panel member 10 near the end wall 22. 
In this embodiment, the panel member 10 is mounted in the top half of a 
wall, while the bottom half is thermally insulated. The flat plate 
collector is disposed outside the thermal insulation on the outer surface 
of the wall. A glazing panel is mounted over both the flat plate collector 
and the panel member. Thus, both the collector and the panel member 
function as apertures for absorbing heat from the sun. Fluid in the 
collector plate moves upward and is stored in the panel member 10 for heat 
radiation into the building. However, heat loss is cut in half by the 
presence of the insulation between the flat plate collector and the 
interior of the building. In other words, the ratio of collection surface 
area to storage surface is two to one. 
By mounting the storage mass above the flat plate collector, reverse 
thermosiphoning does not occur at night. This obviates the need for any 
complex control valves or other devices. The colder water in the bottom of 
the flat plate collector cannot rise to the storage tank. 
In a further variation, the panel member 10 may be located behind one or 
two inches of light transmitting cellular insulating material such as 
expanded styrene or multi-layered film. In this arrangement, the flat 
plate collector covers the entire height of the wall and is made of light 
transmitting material such as acrylic plastic. In this configuration, the 
module provides some daylight while dramatically limiting night losses. 
The modules of FIGS. 1-9 may be filled with water, Glaubers' salt, or any 
other conventional phase change, thermal storage/re-radiation material. 
Where a phase change material is used in place of water, it may be 
preferred to use a thinner panel member, on the order of one inch thick 
instead of seven inches thick. The phase change material may also be 
encapsulated in a plurality of small containers 25 within the water filled 
panel 10 and the module may then be used as a two fluid thermal mass 
panel. 
As is evident, the module of the present invention may be installed in a 
stud space on whichever side or side portions of a building are closest to 
the south. No special pre-planning or building orientation is necessary. 
This provides additional versatility, and is particularly useful in 
factory manufactured buildings where the ultimate orientation of the 
building is unknown at the time of manufacture. 
Although the illustrated embodiments show conventional wooden studs, the 
modules may be used in the walls of buildings having truss-type studs, or 
open-web type construction. 
FIG. 10 shows an alternative embodiment where the inner and outer walls of 
the module 91, 93 are transparent or translucent, for providing daylight 
to the interior of the building. A shelf 90 may be hung on the interior 
wall 91 and plants 92 may be grown thereon. If desired, the water from 
within the panel member 10 may be treated with plant food, and a feed tube 
94 may be provided for direct fluid communication with the plant root 
container 96. In this arrangement, the panel member 10 must be 
periodically refilled. A special funnel 98 may be mounted through an 
opening 100 in the interior wall of the building into the port 102 of the 
panel member 10. 
In a further embodiment shown in FIG. 11, the feed tube 94 may communicate 
with a horizontally disposed hydroponic tank 10'. A panel member 10' is 
shown in a horizontal orientation, with puncture 104 made into its 
upwardly opening recesses. The recesses become wells 106 in which plants 
108 may be hydroponically grown. In this application, heat is radiated to 
the interior of the building from the panel member 10' after the panel 
member absorbs solar radiation through the south facing glass. 
FIG. 12 depicts a further arrangement in which a panel member 10 is mounted 
adjacent an insulation panel 110 to provide an inner loop of a system as 
described in my U.S. Pat. No. 4,294,229, issued Oct. 13, 1981, which is 
incorporated herein by reference. 
In FIG. 13, a recess 111 is shown fitted with a secured in place plug 112. 
In this arrangement, the plug 112 provides a fastener such as a hook 114 
for mounting other objects from the inner wall of the module. For example, 
shelving, brackets, decorative panels, reflecting devices, glazing, frame 
pictures, and other household components may be fastened on the hook 114. 
Alternatively, a plug 116 may be ported at 118 and secured in the recess 
111. An opening 115 into the interior of the panel member provides for 
fluid flow through the plug port 118 and a conduit 120. In this 
arrangement, the fluid from the panel member may be utilized for 
temperature sensing, room humidification, fire safety, or any of the other 
uses depicted in FIGS. 10 and 11. 
The solar absorption of a water-filled unit may also be increased by 
including the quantity of copper sulfate in the water. It is also possible 
to place an intermediate tinted plastic transparent film layer between the 
glazing sheet and the outer wall for increasing the solar absorption of 
the module. Additionally, the thermal storage mass itself may be tinted 
for enhancing solar absorption. 
As shown in FIG. 14, the invention is readily adaptable to installation in 
a conventional window opening of a building. In FIG. 14, the panel member 
140 is mounted within such a window opening on a sill 141. A glazing sheet 
142 covers the outer wall 143 of the panel 140. The glazing sheet 142 is 
mounted at a distance from the outer wall 143 for defining an air space 
144 between the outer wall and the glazing sheet. An intermediate 
transparent glazing layer 145 is disposed between the glazing sheet 142 
and the outer wall 143 for reducing outward heat losses from the module. 
In the illustrated embodiment, a pair of transparent film layers is 
utilized, and a plurality of convection suppression barriers 146 are 
disposed between the transparent film layers 145. These transparent film 
layers 145 serve to reduce heat loss from the module, particularly during 
periods of darkness. The barriers reduce the convection currents between 
the layers, and result in enhanced reduction of heat loss from the system. 
The layers may be coated with an anti-reflective material, or a low 
emissivity coating if desired, for achieving varying effects on overall 
system performance. 
In the embodiment shown in FIG. 14, the transparent film layers are pleated 
for folding in accordion relation. The top end of the transparent film 
layers 145 are attached to the window framework by a top attachment rod 
147. A second attachment rod 148 holds the bottom end of the film layers 
to the lower portion of the window frame. If desired, the lower film 
attachment rod 148 may be unfastened and a mechanism 149 such as that used 
with a venetian blind may be provided for raising and lowering the 
transparent film layers for varying the insulating conditions in the 
building. 
As shown in FIG. 15, the panel member fits readily into the space provided 
in a typical building wall. The inner wall of the panel member 150 extends 
only a short distance beyond the inner surface of the building wall 151. 
By using a phase change material as the thermal mass, a thinner panel 
member may be utilized which fits entirely within the width of a typical 
building wall. In the embodiment illustrated in FIG. 15, the module is 
mounted in an existing window opening of a building with a glazing panel 
152 covering the outer wall 153 of the panel member. A mounting frame may 
also be molded in place around the perimeter of the module. 
In accordance with the invention, the external surface of the outer wall of 
the panel member may be provided with an anti-reflective coating means for 
increasing solar absorption and for transmitting light through the module. 
As embodied herein, and as best shown in FIGS. 16, 16a and 16b, the 
coating means includes a plurality of protrusions 160 molded onto the 
external surface 161 of the module 162. Each of the protrusions has a 
generally upward facing portion and a generally downward facing portion. 
The upward facing portions of the protrusions are darkened or blackened 
for enhancing solar absorption. The downward facing portions of the 
protrusions are translucent for transmitting light through the outer wall. 
The protrusions 160 may be hemispherical, or may be zig-zagged in shape. 
Several alternative means are disclosed for supporting the glazing sheet on 
the module of the invention and for attaching the module to the framework 
of a building. As shown in FIG. 17, the module 170 may have a step 171 
integrally molded thereon for supporting the glazing sheet 172. A 
corresponding locking cap 173 is provided for holding the glazing sheet 
172 in place on the step 171. The locking cap 173 includes a pressure 
finger 174 and the module 170 includes a corresponding cavity 175 for 
receiving the finger 174 in snap-fit relation. It is preferred that the 
finger 174 include a pair of gripping barbs 176 for holding the finger 174 
in the cavity 175. The locking cap 173 exerts pressure against the glazing 
sheet 172 for holding it in place against the step 171. 
FIGS. 18, 19, 20, 21 and 22 all show alternative embodiments for attaching 
the module of the invention to the building framework. In FIG. 18, a 
bracket 180 including an integral flange 181 is utilized for attaching the 
module 182 to the building framework. In the illustrated embodiment, the 
flange 181 is provided with pre-drilled holes for receiving screws or 
nails. The bracket 180 also includes a pair of resilient gripping members 
183 surrounding a slot 184 for receiving a glazing sheet 185 and holding 
it firmly in place. In this embodiment, the panel member 182 has a 
protrusion 186 on each side thereof. The protrusion 186 fits into an 
opening 187 on the bracket 180 and is locked in place against the bracket 
180 by the action of a pair of resilient protrusions 188 on the bracket, 
and a pair of studs 189 on the panel member. 
The module 182 may also include an offset portion 180 for supporting the 
module 182 against the building frame, and for reducing air infiltration 
around the module into the building. This offset portion 180 may abut 
against a framework member for aiding in the installation and alignment of 
the module. 
A similar locking arrangement is shown in FIG. 19. In this embodiment, a 
fastener 190 also includes an integral flange 191 for attachment to the 
building framework. A separate locking cap 192 is provided for gripping 
and supporting the glazing sheet 193 between pairs of resilient fingers on 
the locking cap 192 and the fastener 190. As in the embodiment of FIG. 17, 
the locking cap 192 includes a pressure finger and the fastener 190 
includes a corresponding cavity for receiving the finger in snap-fit 
relation. In addition, however, the fastener 190 includes a further 
resilient finger 194 and the panel member includes a corresponding cavity 
195 for receiving the pressure finger 194 in snap-fit relation for 
attaching the panel member 196 to the fastener 190. In addition, the 
fastener 190 and the panel member 196 each include an integrally molded 
ridge 197 for securing and tightening a pair of transparent film layers 
198. The film layers 198 are supported around the perimeter by a film 
frame 199. The film frame 199 is held in place by the fingers 197 when the 
panel member 196 is attached to the fastener 190. This attachment 
structure provides a simple and efficient means for mounting the module of 
the invention in a building, and for tightening the transparent film 
layers disposed between the outer wall of the panel member and the glazing 
sheet. In addition, it allows for easy removal of the glazing sheet 
without the necessity for removing the panel member, or vice versa. 
FIG. 20 illustrates an alternative fastening structure wherein the fastener 
200 has an opening 201 for receiving a protrusion 202 on the panel member 
203. A resilient finger 204 interacts with the protrusion 202 for locking 
the panel member 203 into position. This structure allows for easy removal 
of the panel member 203 by depressing the resilient finger 204 using a 
suitable tool 205. 
In the embodiment illustrated in FIG. 21, the fastener 210 is attached to 
the panel member 211 by means of an expandable locking arrangement. A bolt 
212 extends through a bracket 213 and the fastener 210 causing a claw 214 
to be displaced into locking relation with a corresponding claw 215 on the 
panel member 211. In this arrangement, the glazing sheet 216 is held in 
place by the bracket 213. 
FIG. 22 shows a further alternative which includes a nailing extension 220 
for attaching the module 221 to the building framework. The attachment is 
accomplished by the use of a fastener 222 which penetrates a 
molded-in-place plug 223. This allows leakproof fastener penetration, 
since the plug 223 is isolated from the thermal mass. 
In the embodiments shown in FIGS. 23 and 24, the interior of the panel 
member 230 is divided into a plurality of chambers 231 which are joined 
for fluid communication therebetween. In this arrangement, the outer wall 
232 of the panel member 230 has a rippled configuration and presents an 
increased surface area for solar absorption. In FIG. 23, an insulating 
layer 233 of one or more layers of film divided into convection 
suppression cells is disposed between the outer wall 232 and the glazing 
sheet 234. In FIG. 24, a pair of transparent film layers 235 are shown in 
the same relative position. 
In FIG. 25, the outer wall 250 of the panel member is molded in the shape 
of a shutter. In this arrangement, the upward facing surfaces 251 of the 
shutter-like portions may be darkened for increasing solar absorption. In 
addition, the module presents the overall appearance of a shuttered window 
when installed in a window frame of a building. In this configuration, the 
lower or downward facing surfaces transmit daylight through the panel 
member into the interior of the building. The shutter-like portions may 
also be separated internally for limiting thermal separation of the mass, 
as mentioned above. 
It will be apparent to those skilled in the art that various modifications 
and variations could be made in the invention without departing from the 
scope or spirit of the invention.