Abstract:
A solar water heater has a rotationally-molded water box and a glazing subassembly disposed over the water box that enhances solar gain and provides an insulating air space between the outside environment and the water box. When used with a pressurized water system, an internal heat exchanger is integrally molded within the water box. Mounting and connection hardware is included to provide a rapid and secure method of installation.

Description:
This invention was made with Government support under Contract #DE-AC36-99G010337 awarded by the United States Department of Energy. The Government has certain rights in the invention. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates to solar water heating devices. More particularly, the invention relates to devices that combine heat collection and hot water storage in a single “passive” unit known as an “integrated collector/storage” or “ICS” unit. 
     2. Description of Related Art 
     Solar energy holds great promise for heating domestic water for residences. However, installation costs for solar water heating systems have typically been too high for economic viability. Solar collection systems of moderate efficiency can typically supply 40 to 70% of annual residential water heating requirements using only 30 to 40 square feet of roof surface. A combination of installation difficulties and high component costs cause paybacks to exceed ten years for these relatively small systems. Available systems divide into active and passive categories. An active system requires a pump and electrical source to circulate water through a rooftop solar collector component, returning the heated water to an insulated water container. A passive system does not require a pump to circulate water or other heating fluid. Integral collector/storage (ICS) units offer particular promise for reducing costs because they minimize the total surface area of system components, in addition to eliminating moving parts and electrical connections. 
     ICS designs have been in use for many years. Traditional “breadbox” ICS units place a cylindrical metal tank under a glazing. The tank is typically under city water pressure. When the sun shines, water passing through the tank is heated on its way to fixtures or an auxiliary water heater. While many such breadbox units have been site-built, several U.S. manufactured units were widely marketed in the 1970&#39;s and early 1980&#39;s until federal and state tax subsidies were no longer available. These units used either stainless steel or “glass-lined” steel tanks placed in insulated boxes. Plastic glazings were used as top covers to admit solar energy and limit tank losses to the environment during non-solar conditions. The tanks for “breadbox” units typically contain 30 to 60 gallons of water. The concentrated weight of the units, due to the water, further complicated installation because roof reinforcement was often required. While overnight tank losses limit ICS “solar fraction” compared to active systems with well-insulated indoor tanks, the lower installed cost, and the elimination of energy costs for pumping, give ICS units an advantage in many applications. 
     Although less costly than active systems, available ICS systems are still too expensive for significant market penetration in either new home or retrofit applications. Two ICS units currently being marketed resolve the concentrated weight problem by using a “parallel tube” design that distributes the pressurized water relatively uniformly in a rectangular box. For example, a 3′ by 8′ ICS unit places 6 or 8, 3″ to 4″ diameter horizontal tubes side-by-side, joining them at alternating ends to create a serpentine flow pattern from cold water entering one end of the bottom tube to solar-heated water leaving the tube at the top. However, these simple, durable units are expensive to manufacture due to the high cost and weight of the large copper tubes needed to contain pressurized water without corrosion. 
     Unnecessarily high manufacturing costs of known ICS systems also result from the design of the enclosure that surrounds the parallel tube array. A flat rectangular box with 4″ internal tubes is typically fabricated from 7″ tall aluminum perimeter extrusions. A flat ⅛″ thick glass cover sheet is held to the perimeter members with a smaller aluminum extrusion forming a channel that includes a small rubber channel gasket strip that captures the glazing. The corners of the aluminum extrusions are mitered and secured with corner clips. The lower outsides of the main extrusion profile have features that accommodate aluminum clips for securing the ICS unit to the roof rack that is secured to the roof. An aluminum sheet bottom panel is also supported by the perimeter extrusions. The bottom and walls are typically lined with about 1″ of rigid isocyanurate foam insulation that is cut from larger panels. All of the enclosure components are relatively expensive, and require substantial factory labor to prepare and assemble. 
     Although the uniform weight distribution of available ICS units somewhat reduces installation difficulties, these “parallel tube” ICS units still require substantial on-site labor to install. Furthermore, a unit will typically weigh at least 300 pounds before filling with water, requiring a crane or boom truck to lift into place. The units are usually supported above the roof surface on racks that require four connection points through the roof. Such rack-mounting is customary to allow the roof to “breath” under the collector, where debris and moisture might otherwise collect and rot, thereby accelerating roof degradation. Because the spacing of roof structural members may vary, securing the rack often becomes a custom project. Also, the required piping penetrations are not at the four support bolt locations, resulting in at least six different roof penetration locations, each requiring careful sealing and/or flashing to prevent leakage. Such mounting methods also risk damage to the roof structure, since bolts driven downward into roof structural members (now more heavily loaded) may weaken the structural members. 
     Current breadbox solar water heaters also have aesthetic liabilities associated with their size and rack mounting. One of the damaging legacies from the failed solar heating movement of the 1970&#39;s and early 1980&#39;s is that roof-mounted solar heating equipment is not particularly attractive. Units 8″ thick supported on racks another 4″ above the roof have high visibility, and look out of place on many residential roofs. 
     For these and other reasons, there is a need for a low cost, lower profile ICS solar water heater that can easily and quickly be installed on both new or existing residences, that minimizes the danger of water leakage through the roof, and that brings solar water heating into an affordable budget range for households in sunny climates throughout the world. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an integrated collector/storage (ICS) solar water heater. The apparatus and methods of the invention include the use of molded polymer technology to reduce the cost of materials and the number of parts that must be assembled to manufacture the ICS unit. The invention also includes support and connection features that eliminate the need for a mounting rack, significantly reducing the cost of installation labor, and reduces or minimizes the likelihood of leakage at mounting surface penetration points. 
     In an exemplary embodiment of the invention, the apparatus and methods of the improved ICS solar water heater include a rotationally-molded fluid container (“water box”) with an internal heat exchanger, a glazing subassembly, and a mounting/connection hardware kit. In one embodiment, the heat exchanger contains pressurized water in small, thin-walled copper tubes that are surrounded by solar heated water in the water box which is under “atmospheric pressure”. Because the water box is not pressurized beyond atmospheric pressure, the walls of the water box may be relatively thin, as compared to existing ICS units, thereby decreasing weight, reducing production costs and improving heat transfer. In the exemplary embodiment, the water box comprises two essentially parallel sheets, joined by spaced “through-connects”, and four sides providing a closed perimeter. The water box may be produced by rotational molding. 
     In an exemplary embodiment of the apparatus and methods of invention, the molded fluid container, or water box, is designed to rest directly on a mounting surface, such as a roof surface by using a water box having a ribbed bottom with vent passages that are open along their lower edge. The space formed between the ribs may be closed at their upper ends to prevent debris from being deposited under the water box. This feature provides for ventilation between the water box and the mounting surface to remove moisture. 
     In an exemplary embodiment of the apparatus and methods of invention, the water box is tapered from a narrower profile at the bottom of the water box to a thicker profile at the top of the water box. The taper provides more internal space in the top portion of the water box, where the heat exchanger is located, and reduces the length of the through-connects at the bottom portion of the water box, where water pressure is highest. 
     In an exemplary embodiment of the apparatus and methods of invention, the water box may include a metal underside strut located in a vent passage of the water box formed by the ribs disposed on the bottom surface of the water box. The strut facilitates connection of the ICS unit to a single structural member on a mounting surface, thereby simplifying layout and connections by eliminating the need to consider varying spacings of particular structural members, such as roof rafters or trusses, for example. The strut may be integrated with mounting hardware, such as upper and lower brackets and mounting plates that are pre-secured to the mounting surface thereby facilitating the rapid and secure mounting of the ICS unit. For example, in an exemplary embodiment, the brackets surround a framing member thus avoiding weakening the member by driving large fasteners such as lag bolts into the framing member. 
     In yet another exemplary embodiment of the apparatus and methods of the invention, the glazing subassembly includes a formed polymer glazing with integral ribs and a rim that minimize the size of the rigid perimeter extrusions that strengthen the lower glazing edge, hold two flexible sealing strips, and facilitate securing the glazing subassembly to the water box and mounting points. 
     In an exemplary embodiment of the apparatus and methods of the invention, mounting hardware is provided that connects to the strut disposed on the underside of the water box and facilitates all connections between the mounting surface and the ICS unit along the vertical centerline of the unit. In an exemplary embodiment, the hardware for mounting the ICS unit on a roof includes below-roof brackets and above-roof mounting plates. The below-roof brackets surround a rafter or truss framing member and provide connection means to the above-roof plates. In addition to providing a secure connection that does not damage the framing member, the top bracket also holds and aligns the supply and return water lines for connection to the heat exchanger stub-outs of the water box. The upper above-roof mounting plate also includes a closed-cell foam gasket to provide a seal around roof penetrations. The lower above-roof mounting plate also provides a seal around roof penetrations. 
     These and other features and advantages of this invention is described in or are apparent from the following detail description of various exemplary embodiments of the systems and methods according to the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various exemplary embodiments of the apparatus and methods according to this invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein: 
     FIG. 1 is an exploded isometric view of the water box subassembly and the glazing assembly of an exemplary embodiment of the invention; 
     FIG. 2 is a vertical cross-sectional view through the center of an exemplary embodiment of an ICS solar water heater according to the invention; 
     FIG. 3 is a horizontal cut view through the principal plane of an exemplary embodiment of the ICS unit according to the invention; 
     FIG. 4 is a vertical cross-sectional view of the top portion of an exemplary embodiment of the ICS unit according to the invention; 
     FIG. 5 is a vertical cross-sectional view of the bottom portion of an exemplary embodiment of the ICS unit according to the invention; 
     FIG. 6 is an exploded view of an exemplary embodiment of the top mounting hardware set according to the invention; and 
     FIG. 7 is an exploded view of an exemplary embodiment of the bottom mounting hardware set according to the invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Various exemplary embodiments of the apparatus and methods according to the present invention are described hereafter, with reference to the drawings. 
     FIG. 1 shows an exploded isometric view of the water box subassembly  2  and the glazing subassembly  20  of an exemplary embodiment of the invention. FIG. 2 shows a vertical cross-sectional view of an exemplary embodiment of the invention including a polymer-based ICS solar water heater having a water box subassembly  2  and a glazing subassembly  20 . FIG. 3 shows a horizontal cut view through the principal plane of the ICS solar water heater including the water box subassembly  2  and through-connects  11 , a heat exchanger  3  contained within the water box  2   a , and locations of exemplary connections through the roof. These and other features of an exemplary embodiment of the present invention are described in the following paragraphs with reference to FIGS. 1-3. 
     As shown in FIGS. 1-3, an exemplary embodiment of the invention includes an ICS unit  1  having a water box subassembly  2  and a glazing subassembly  20 . The water box subassembly  2  is comprised of a molded fluid container, or water box  2   a , an internal heat exchanger  3  with a water inlet  4  and a water outlet  5 , fill ports  6  and fill port covers  6   a , and a connection strut  7  with a support toe  32 . 
     In an exemplary embodiment, the water box  2   a  may be molded with the internal heat exchanger  3  already in place using rotational molding. In the embodiment, rotational molding of the water box  2   a  facilitates the formation of a sealed, one-piece water box at a relatively modest cost. The rotational molding process also allows pre-placement of the heat exchanger  3  in the mold. 
     Although the exemplary embodiment shown if FIGS. 1-3 includes a water box  2   a  having an internal heat exchanger  3 , the invention also contemplates a water box  2   a  without a heat exchanger  3 . For example, a gravity flow hot water outlet may be used such that hot water in the water box  2   a  flows directly to fixtures. A water inlet float valve assembly, or other fill device, may be used to replenish the water level in the water box  2   a.    
     During the molding process, the heat exchanger  3  is placed in a mold and granular plastic is fed into the mold. The mold is then heated and rotated to form the water box  2   a . The finished water box  2   a  emerges from the mold with an internal heat exchanger  3  having extensions penetrating through a surface of the water box  2   a  that are leak resistant and/or leak proof. Structural connections, or through-connects  11 , may also be placed in the mold prior to processing. In an exemplary embodiment of the invention, the through-connects  11  may be shaped as truncated cones having tapered walls and are formed integrally with the absorber  9  and the bottom box wall  10  during the molding process. The tapered walls of the truncated cone shape assist in de-molding the water box  2   a  after the melted plastic granules are uniformly distributed or “sintered” on the mold walls. Because the ICS unit  1  must withstand summer “stagnation” conditions, i.e., substantial solar input and no hot water draws, a relatively high temperature polymer, for example, cross-linked polyethylene, or the like, may be used for the formation of the water box  2   a . In an exemplary embodiment of the invention, the polymer may be stabilized with carbon black, or the like, to limit UV degradation due to incident sunlight. 
     Because the heat exchanger  3  contains pressurized domestic water, the ICS unit  1  does not need to withstand the 40 to 80 psi internal pressure of known ICS units having large cylindrical tanks and/or large diameter copper tubes. In an exemplary embodiment of the invention, an ICS unit  1  about 4′ high and about 8′ wide that is mounted at about a 45° slope, has a maximum internal pressure at the bottom portion of the water box  2   a  that is less than about 1.3 psi. Even at this low pressure, structural connections may be disposed between the absorber surface  9  and the bottom box wall  10  to withstand hydraulic loads. 
     In an exemplary embodiment of the invention, the height of the water box  2   a  is tapered from a narrower profile at the bottom end to a thicker profile at the top end. The taper provides more internal space in the top portion of the water box  2   a , where the heat exchanger  3  is located. The taper also reduces the length of the through-connects  11  located at the bottom portion of the water box  2   a  where water pressure in the water box  2   a  is highest and the through-connects  11  are most closely spaced. The taper also tilts the absorber surface  9  to a more favorable angle on most mounting surfaces, such as roofs having a relatively low slope, to absorb sunlight. The low profile of the ICS unit  1  also improves the appearance of the roof by reducing the profile of the ICS unit  1  roof at the lower edge of the roof where the ICS unit  1  is most visible. 
     The water box  2   a  also has four edges  9   a  that slope inward from the bottom box wall  10  toward the absorber surface  9 . Thus, the edges  9   a  function as part of absorber surface  9  thereby eliminating the need for side insulation and further lowering the apparent profile of the ICS unit  1 . 
     In an exemplary embodiment, the water box  2   a  includes a ribbed bottom that allows the water box to be placed directly on a mounting surface. In the embodiment, vertical ribs  10   a  extend downwardly from the bottom box wall  10  to create air spaces between the ribs  10   a  and prevent moisture from accumulating between the ICS unit  1  and the mounting surface. In an exemplary embodiment, the ribs  10   a  extend approximately ½″ below the bottom wall  10  and may be approximately 1″ wide and spaced apart on 3″ centers. The through-connects  11  may be placed between alternating ribs. In an exemplary embodiment, the ribs  10   a  may be closed along the top edge  9   a  of the water box  2   a  to prevent continuous upward air circulation between the ribs  10   a  and allow moisture to vent outward at the lower edge  9   a  of the water box  2   a.    
     In an exemplary embodiment, the vertical spacing pattern of the through-connects  11  may be varied in recognition of the load pattern. For example, the through-connects  11  may have a closer spacing at the bottom of the panel where internal pressure is greatest. In another exemplary embodiment, the rows of through-connects  11  located near the bottom end of the water box  2   a  may be spaced at 4″ apart and through-connects located near the top end of the water box  2   a  may be spaced at 6″ apart. In an exemplary embodiment, all through-connects  11  have a cone shape with a one-way taper that narrows toward the top, where the cones are closed. 
     In an exemplary embodiment of the invention, special through-connects  12 , located on each side of a horizontal centerline of the water box  2   a , are tapered inwardly from the absorber surface  9  and the bottom box wall  10  toward the horizontal centerline of the water box  2   a . The tapered cones meet at an intersection that surrounds and holds vertical tubes  13  of the heat exchanger  3 . The special through-connects  12  retain the heat exchanger  3  away from the surfaces of the water box  2   a  and prevent leakage and improve performance of the water box  2   a  by minimizing the amount of polymer that adheres to heat exchanger  3  during the molding process. 
     In an exemplary embodiment of the invention, the internal heat exchanger  3  may be self-supporting and placed to take advantage of the thermal stratification that develops inside the ICS unit  1 . The inlet  4  and the outlet  5  may be located near the top of the water box  2   a  to provide convenient access to the connections. A recess  14  disposed near the top of the water box  2   a  provides a surface through which the inlet  4  and the outlet  5  emerge and forms a space for completing plumbing and/or mounting connections. In an exemplary embodiment, both the inlet  4  and the outlet  5  may be of ¾″ nominal Type M copper tube, or the like. Although ¾″ Type M copper tube is disclosed in the exemplary embodiment, other tubing and/or pipe, as well as other nominal wall thicknesses, are contemplated by this invention. 
     Inside the water box  2   a , the inlet  4  and the outlet  5  connect to tees  16  and  17 , respectively, that turn into the horizontal plane of the water box  2   a  and direct water from connection tubes  50  to flow horizontally to two parallel heat exchanger tube sets. The two outlets from the tee  16  connected to the inlet  4 , and the two the inlets to the tee  17  connected to the outlet  5 , may be of ⅜″ nominal Type M tube. The ⅜″ tubes are bent or formed into a serpentine shape to form two parallel fluid flow paths of the heat exchanger  3  (FIG.  3 ). Other sizes and wall thicknesses of pipe and/or tubing may also be used to form the parallel flow paths. 
     In operation, the inlet water enters tee  16 , whose two outlets proceed horizontally and down to become vertical tubes  13  and pass through special through-connects  12  supporting the heat exchanger  3 . Near the midline of the water box  2   a , the tubes  13  turn horizontally to begin their upward serpentine path. The horizontal serpentine runs are secured to vertical tubes  13  to maintain the serpentine pattern and hold all tubes in the desired plane. Near the top of the unit, the two serpentine sections meet at tee  17  to proceed downward through the outlet  5 . 
     In an exemplary embodiment, fill ports  6  are disposed near the top corners of the water box  2   a  and are equipped with covers  6   a  to prevent water and vapor loss from the water box  2   a . In an exemplary embodiment, the fill ports  6  may have a diameter of about 1-¼″ to allow a standard garden-type hose to be inserted into the water box  2   a  and allow adequate room for internal air to escape as water fills water box  2   a . Although the fill ports are disclosed in the exemplary embodiment as having a diameter of about an 1-¼″, other size fill ports are contemplated by this invention. 
     In an exemplary embodiment, the water box subassembly  2  includes a strut  7  disposed beneath the water box  2   a  and connected to the water box  2   a  with a bolt  8  that mates with a nut  19  connected to the underside of the strut  7  through a hole  15  that has been molded along a vertical centerline of the water box  2   a . The strut  7  enables rapid connection of the ICS unit  1  to a mounting surface using the mounting hardware, as will be further described herein with reference to FIGS. 4-7. The strut  7  is attached, preferably by welding along all adjoining surfaces, to a support toe  32  at its lower end. The support toe  32  may be either a simple channel shape or be formed to match the profile of the bottom edge  9   a  of the water box  2   a . The strut  7  further includes an upper slotted hole  71  for connection to the roof mounting hardware (FIG.  6 ). The strut  7  may be connected to the water box  2   a  before the glazing subassembly  20  is secured to the water box subassembly  2 . 
     In an exemplary embodiment, the strut  7  is a “legs-down” channel-type and includes a horizontal pin  29  spanning between and connected to both sides of the connection strut  7  channel. In an exemplary embodiment, the steel pin  29  may have a diameter of about {fraction (5/16)}″ diameter and interlock with the recess  81  in a bottom plate  62 , as will be further discussed with reference to FIG.  7 . Other size pins are contemplated by this invention. 
     In an exemplary embodiment, the glazing subassembly  20  includes a glazing panel  21 , edge extrusions  22 , and other features that will be subsequently described with reference to FIGS. 3 a  and  3   b . In an exemplary embodiment, a molded polymer glazing panel  21  is thermo-formed to provide increased strength from a relatively thin polymer sheet. For example, polycarbonate and/or acrylic materials may be used in this application. However, it is recognized that known polycarbonates display greater strength at high temperatures. Although a molded polymer glazing is described in the exemplary embodiment, other glazing materials currently available or later developed may be used. 
     In an exemplary embodiment of the invention, the panel  21  may be configured with ribs  21   a  extending downwardly from the glazing panel  21 . The surface of the absorber  9  may be configured with raised nubs  18  to maintain an airspace of approximately ¼″ between the underside of the ribs  21   a  and the absorber surface  9 . In an exemplary embodiment, the ribs  21   a  may be spaced about 12″ apart and be about 1″ deep to create a gap of approximately 1-¼″ between the absorber surface  9  and the glazing panel  21 . In another exemplary embodiment, the raised nubs  18  may project downwardly from the glazing ribs  21   a  toward the absorber  9 . 
     FIGS. 4 and 5 are vertical cross sectional views showing the top and bottom portions of the ICS unit  1 , respectively. In FIGS. 4 and 5, the glazing subassembly  20  includes extrusions  22  and other components that facilitate connecting the glazing subassembly  20  to the water box subassembly  2  and to the mounting components. Features not previously identified in FIGS. 1-3 include an upper sealing strip  24 , a lower sealing strip  25 , screws  26 , and nuts  27 . FIG. 5 also shows components of the connection between the ICS unit  1  and the roof mounting hardware. 
     In an exemplary embodiment, extrusions  22  include recesses  30  that hold downtumed edge  23  of glazing panel  21 , a projection  28  that retains an upper sealing strip  24 , and a recess  33  that retains a lower sealing strip  25 . The upper sealing strip  24  is disposed around the entire perimeter of the ICS unit  1  to support the glazing subassembly  20  on the lower sloping edge  9   a  of the absorber surface  9 . The upper sealing strip  24  maintains an air seal along the top and sides of the ICS unit  1  to prevent continuous circulation of air into ICS unit  1 . The upper sealing strip  24  also prevents and/or reduces thermal loss from the ICS unit  1 . 
     The lower sealing strip  25  is used along the top end and sides of the water box  2   a  to provide a seal between the ICS unit  1  and the mounting surface. However, the lower sealing strip  25  is not used along the bottom end of the water box  2   a  to allow the underside of the ICS unit  1  to “breathe”. Instead, a woven strip  35  may be disposed along the bottom to allow air and moisture transfer and prevents foreign objects from entering the air vent spaces. 
     In an exemplary embodiment of the invention, screws  26  connect extrusion  22  to receiving nuts  27  pre-placed at the middle and outer edges of the support toe  32 , at the bottom end of the water box  2   a , to secure the glazing subassembly  20  to the water box subassembly  2 . Although screws are used as a means of attachment, use of other fasteners are contemplated by this invention. The support toe  32  may be essentially the full width of water box  2   a , to provide additional strength resisting wind uplift at the narrow bottom of the ICS unit. This glazing-to-toe connection allows the glazing subassembly  20  to lift upward sufficiently at its top edge for connecting and filling the unit. Removing screws  26  allows the glazing subassembly  20  to be removed from the ICS unit  1  for replacement without disconnecting or moving the water box  2   a.    
     FIGS. 6 and 7 are exploded views of mounting hardware used at the upper and lower ends of the ICS unit  1 , respectively, showing how the water box subassembly  2  and the glazing subassembly  20  integrate with mounting hardware components above and below the mounting surface. Although the ICS unit  1  may be mounted to any surface, roof mounting will be discussed as an exemplary mounting surface. The components shown in FIG. 6 include an upper bracket  40  that is placed below the roof and an upper plate  60  that is placed above the roof during installation. The components shown in FIG. 7 include a lower bracket  36  that is placed below the roof and a lower plate  62  that is placed above the roof. These features provide rapid, secure, waterproof roof mounting of the ICS unit  1  without damage to the roof structure. 
     Operations to place, connect, and fill the ICS unit, and to remove components for service and replacement, according to exemplary embodiments of the invention, are discussed with reference to FIGS. 6 and 7. During system installation, the top edge of the glazing subassembly  20  is secured to the mounting system as described with reference to FIG.  6 . 
     Installation of the ICS unit  1  begins by using an underside template to drill one upper bracket/plate connecting hole. A top-side template is then used to locate the remaining holes for both the top and bottom connections and inlet/outlet pipes. The following description assumes these holes have been drilled before top and bottom mountings are completed. The top mountings are described before the bottom mountings. 
     In an exemplary embodiment, an upper bracket  40  fabricated of 16 gauge galvanized steel, or the like, is placed below the roof sheet (not shown) and comprises a bottom  41 , sides  42 , flanges  43  extending orthagonally from the sides  42 , and wingpieces  44  connected to the bottom and extending perpendicularly outwardly beyond the sides  42 . The bottom  41  is of sufficient size to provide clearance for sides  42  as the upper bracket  40  surrounds a framing member (not shown). In other exemplary embodiments, the upper bracket  40  may be made available in several widths to accommodate alternate framing systems and dimensions. For example, in U.S. applications, 1-½″ wide framing members are typically used in new construction. In an exemplary embodiment, “standard” upper bracket  40  therefore has 1-⅝″ inside clearance for bottom  41 . However, in some “timber” structural systems the framing members are as wide as 3-½″, and would therefore use a “non-standard” bracket. In an exemplary embodiment, holes drilled in the roof to allow pipes and/or tubing to be connected to the inlet  4  and the outlet  5  may be spaced approximately 5″ apart to accommodate most roof framing techniques. 
     The sides  42  of the upper bracket  40  extend upwardly to contact the underside of a roof sheet at the flanges  43 . The upper bracket  40  may be temporarily held to the framing member (not shown) by various means such as screws or clamps if necessary prior to placement of the upper mounting plates. 
     The bracket wingpieces  44  include at least one pipe penetration hole  52  to hold and/or receive fluid supply and return connection tubes  50  in alignment until connections are made in the flange  43  above the roof. In an exemplary embodiment, the bracket wingpiece  44  may include a tab  51  having a penetration hole  52  and a screw  53  that passes through a threaded hole  54  in the tab  51  to retain the tubes  50  that penetrate holes  49 . The bracket wingpieces  44  may be fabricated of 16 gauge galvanized steel, or the like, and connected to the bottom  41  or the upper bracket  40 . The holes  49  and  52  align with holes pre-drilled in the roof sheet to allow tubes  50  to pass through and may include grommets  55  that isolate the supply and return connection tubes  50  from the flange  43  and bracket wingpiece  44 , respectively. After the upper bracket  40  is secured to the framing member, the connection tubes  50  are pushed through the aligning holes  49  and  52 , and are held in their position as the screws  53  are tightened. This exemplary embodiment allows a single installer to secure the pipes. In an alternate exemplary embodiment, screws  53  that are on the connection tubes  50  are not used and the connection tubes  50  are held in place by the compression fittings  58  above the roof sheet, placed by a second installer on top of the roof. Each flange  43  also includes two holes  56  and two nuts  57  connected to the underside of the flange  43  to receive mounting bolts (not shown) from above. 
     An upper plate  60  includes a rim  61  extending perpendicularly upward from the plate  60 , a nut  63  affixed to the plate  60  to receive bolts  71  that connect the upper end of the ICS unit  1  to the strut  7 , bracket connection holes  64 , glazing connection holes and nuts  59  disposed on the rim  61 , and tubing holes  49 . Other parts of the mounting hardware include mounting bolts  65  and foam gasket  66 . The upper plate  60  disposed above the roof sheet completes a clamp around the framing member to provide a rapid and secure connection to the glazing top edge  22  to resist wind uplift, and helps prevent water leakage around the roof penetrations. The upper plate  60  may be fabricated of 10 gauge galvanized steel, or the like. As the upper plate  60  is tightened against the roof surface using four mounting bolts (not shown) that connect into nuts  57 , the foam gasket  66  is compressed to seal around the connection tubes  50  and the mounting bolts, as well as between the upper plate  60  and the roof. The rim  61  deflects roof water away from the connections, and caulking will typically be applied between the upper plate  60  and the roof surface (not shown). 
     During installation the four mounting bolts are driven through the holes  64  in the upper plate  60  into the nuts  57  on the upper bracket  40 . In an exemplary embodiment, the gasket  66  may be made of a closed-cell gasket material that assists the rim  61  in preventing water leakage. The thickness of the gasket  66  may be varied according to the nature of the mounting surface. 
     Connection tubes  50  are inserted through the holes  52 ,  49  in the bracket wingpiece  44 , flange  43  and upper plate  60 , respectively. The connection tubes  50  may be temporarily secured using either of the methods described above. 
     At the lower end of the ICS unit  1 , the roof is clamped between the lower bracket  36  and the lower plate  62  (FIG.  7 ). The lower bracket  36  has a U-shape including a bottom  39 , two parallel sides extending upwardly from the bottom  39 , and flanges  38  extending at right angles from the sides. Nuts  57  are attached to the flanges  38  under clearance holes  56  in the flanges  38 . In an exemplary embodiment of the invention, the bottom  39  of the lower bracket  36  is wider than the bottom  41  of the upper bracket  40  to allow the lower brackets to align vertically if the framing member  45  is not plumb. The mounting bolts  65  are driven through clearance holes  64  in the lower plate  62  disposed above the roof sheet, and clearance holes  56  located in the flanges  38  of the lower bracket  36  into nuts  57  to clamp the lower mounting system. In an exemplary embodiment, doughnuts (not shown) may be disposed over the clearance holes  56  to form a seal between the lower bracket  36  and the lower plate  62 . The doughnuts  37  that may be made of a closed cell foam, are compressed to seal the roof penetrations when the mounting bolts  65  are tightened into the nuts  57  to hold the lower plate  62  tightly against the roof surface. The lower plate  62  is bracket-shaped and includes recess  81  to receive a connecting pin  29  on the connection strut  7  of the ICS unit  1  (FIG.  5 ). 
     After the upper plate  60  and the lower plate  62  are secured in place and the compression fittings  58  are placed on the connection tubes  50  and tightened, the roof is ready to receive the ICS unit  1 . The roof is watertight at this point, so the ICS unit  1  may be installed at any convenient time without worry of leakage at the roof penetrations. 
     To install the ICS unit  1  to the upper plate  60  and the lower plate  62 , the lower edge of the ICS unit  1  is lowered into position such that the connecting pin  29  in the connection strut  7  engages with the recess  81  in the lower plate  62 . With the connecting pin  29  engaged, the upper edge of ICS unit  1  is then lowered into position. The upper rim of glazing subassembly  20  is lifted and/or tilted to expose the connection recess  14  (see FIG. 4) at the top of the ICS unit  1 . With the glazing assembly  20  lifted and held in position, the installer guides the inlet  4  and the outlet  5  of the heat exchanger  3  into the ends of the compression fittings  58 . The upper edge of the ICS unit  1  may then be lowered into position so that the underside of the connection strut  7  contacts the upper plate  60 . The ends of the inlet  4  and the outlet  5  are tapered to a slightly smaller diameter than the inside of the compression fittings  58  to facilitate insertion of the inlet  4  and the outlet  5  into the compression fitting  58 . When the inlet  4  and the outlet  5  are fully inserted into the compression fitting  58 , the compression nuts on the compression fittings  58  are tightened to make watertight connections. 
     In this position the slotted hole  31  at the upper end of the connection strut  7  aligns with a nut  63  connected to the upper plate  60 . A bolt  71  is driven through the slotted hole  31  in the connection strut  7  into the nut  63  on the upper plate  60  to structurally secure the top of ICS unit  1  to upper plate  60 . The water box  2   a  may now be filled with water, as described above, using the fill ports  6  with the caps  6   a  removed therefrom. After the ICS unit  1  is filled with water and the caps  6   a  are replaced on the fill ports  6 , the heat exchanger  3  may be pressurized and the compression fittings  58  checked for leakage. When the compression fittings  58  are made watertight, the glazing subassembly  20  is lowered into a closed position and glazing bolts  67  are inserted through clearance holes  68  in the top extrusion  22  and screwed into receiving nuts  59  disposed in the rim  61  of the upper plate  60  to complete installation of the ICS unit  1  on the roof. 
     In various exemplary embodiments, the ICS unit  1  may be installed with or without underside insulation. This insulation may be placed on the underside of the panel and ribbed to match, or may be blankets placed between the roof framing members under the roof. 
     Although the invention has been described with reference to various exemplary embodiments thereof, it is to be understood that the invention is not limited to the exemplary embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the exemplary embodiments are shown in various combinations and configurations, others combinations and configurations, including more, less, or only a single element, are also within the spirit and scope of the invention.