Abstract:
A flexible heat exchanger is incorporated into a ridge vent to form an assembly. The heat exchanger operates by collecting thermal energy (heat) from heated air exhausting from the attic space via the ridge vent. Air in the attic space is typically heated by the solar energy falling on the roof. Heat from this air is transferred through the wall of heat exchange tubes integrated into the ridge vent. The flow of heated air around the outside of the tubes is driven by the column of heated air that forms in the attic space, similar to the draft in a chimney. The chimney effect in the attic space circulates the flow of outside air into the soffit vents through the attic space where it is heated and then exhausted out the ridge vent, passing by and around the tubes before it exits.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 12/386,805, filed Apr. 23, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/012,072 filed Feb. 1, 2008, which claims the benefit of U.S. Provisional Patent Application Nos. 60/921,863 and 60/921,867, both filed Apr. 5, 2007. 
         [0002]    The present disclosure relates to roof vents generally and more particularly to a method for manufacture of an integrated ridge vent and heat exchanger. 
     
    
     BACKGROUND 
       [0003]    Structures incorporating sloped roofs typically include an attic space immediately beneath the roof rafters and above the occupied portions of the structure. The ceiling of the occupied portions of the structure, corresponding to the floor of the attic space, is typically insulated to thermally isolate the rest of the structure from what can be extreme temperature fluctuations in the attic space. The attic space is typically provided with ventilation designed to prevent the accumulation of heat and moisture in the attic space. 
         [0004]    Various forms of attic ventilation are well known. Roof ridge vents are commonly used to cover an opening formed along the peak of a sloped roof during construction of the structure. The roof ridge vent takes the form of an elongated slot between the structural elements of the roof. Various forms of vent covers are attached to the roof structure surrounding the vent opening and are configured to allow air to leave the attic space, while preventing moisture, insects and the like from entering. Complementary vents are typically formed under the eaves of the roof and may be referred to as soffit vents. This combination of soffit and ridge vents work in combination with solar heating of the roof structure to establish a natural convective circulation of heated air entering at the soffit vents and exiting the roof structure at the ridge vent. Depending upon the time of year, geographic location of the structure (latitude), and ambient temperature, air within the attic structure can reach temperatures exceeding 160° F. Attic ventilation is typically arranged to limit accumulation of heat in the attic space and therefore limit transfer of unwanted heat from the attic space to the occupied portions of the structure. 
         [0005]    It is known to use of the reservoir of heated air in an attic space as an energy source. Previous efforts to extract energy from the heated air beneath a roof structure have typically required the installation of complicated and expensive equipment in the attic such as disclosed in U.S. Pat. No. 5,014,770, which also includes a useful summary of other prior art arrangements used to extract energy from the air space beneath a roof structure. Some of the prior art requires assembly of large heat exchange apparatus in the attic space, such as that disclosed in U.S. Pat. No. 4,671,253. 
         [0006]    An objective of the present disclosure is to provide a method for manufacturing a cost-effective system for recovering a portion of the energy represented by heated attic air exiting through attic vents. 
         [0007]    Another objective of the present disclosure is to provide a method for manufacturing integrated heat exchangers and roof ridge vents including a heat exchanger that recover useful energy from the air space beneath a roof structure without requiring installation of equipment in the attic space or extensive modification of the roof structure. 
       SUMMARY 
       [0008]    A flexible heat exchanger is incorporated into a ridge vent to form an assembly. The heat exchanger operates by collecting thermal energy (heat) from heated air exhausting from the attic space via the ridge vent. Air in the attic space is typically heated by the solar energy falling on the roof. Heat from this air is transferred through the wall of heat exchange tubes integrated into the ridge vent. The flow of heated air around the outside of the tubes is driven by the column of heated air that forms in the attic space, similar to the draft in a chimney. The chimney effect in the attic space circulates the flow of outside air into the soffit vents and through the attic space where it is heated and then exhausted out the ridge vent, passing by and around the tubes before it exits. This chimney effect requires a warmer temperature inside the attic than the ambient outside temperature, which is typically the case during daylight and into the evening hours. The heat transfer coefficient outside the tubes, created by the velocity of the air flowing around the tubes, is the limiting thermal resistance to heat flow in the process of transferring heat to the fluid inside the tubes, assuming that the velocity inside the tubes is sufficiently high—typically at or above 3 feet per second. 
         [0009]    The disclosed ridge vent heat exchanger assembly is manufactured in long flexible coils so that it can be rolled lengthwise during manufacture for storage and transport and unrolled to cover elongated openings such as roof ridge vent openings and capped in a conventional manner with shingles. Lateral side portions are configured from open, air permeable material such as mesh or thermoformed plastic materials. The lateral side portions serve two functions. First, they provide support to the cap of shingles. Second, they provide an elongated, air permeable vent for the exit of heated air from beneath the roof. The lateral side portions also include screen or fine mesh material to prevent the entry of insects or opportunistic animals. The lateral side portions are separated by an open central region having a width similar to that of the underlying opening along the roof ridge. The plurality of heat exchange tubes are suspended in the open central portion and exposed to the flow of heated air exiting through the vent opening. 
         [0010]    According to one aspect of the disclosure, the flexible roof ridge vent material may be provided with a plurality of longitudinally spaced hangers constructed to support the heat exchange tubing. The hangers include receptacles configured to receive and support each of the plurality of heat exchange tubes. Each set of hangers may extend downwardly from a bracket extending laterally across the roof ridge vent. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a partial sectional perspective view of a first embodiment of a heat exchange assembly according to aspects of the disclosure; 
           [0012]      FIG. 2 , is a sectional view of a roof structure incorporating the heat exchange assembly of  FIG. 1 ; 
           [0013]      FIG. 3  is a partial sectional perspective view of a second embodiment of a heat exchanger according to aspects of the present invention; 
           [0014]      FIG. 4  is a sectional view of a roof structure incorporating the heat exchange assembly of  FIG. 3 ; 
           [0015]      FIG. 5  is a sectional view of an alternative roof structure incorporating the heat exchange assembly of  FIG. 3 ; 
           [0016]      FIG. 6  is a schematic of an energy recovery system incorporating a heat exchanger according to the present disclosure; 
           [0017]      FIG. 7  is a partial sectional perspective view of a ridge vent heat exchanger assembly according to aspects of the present disclosure; 
           [0018]      FIG. 8  is a partial sectional perspective view of a second ridge vent heat exchanger assembly according to aspects of the present disclosure; 
           [0019]      FIG. 9  is a partial sectional perspective view of a third ridge vent heat exchanger assembly according to aspects of the present disclosure; 
           [0020]      FIG. 10  is a perspective view of a bracket compatible with the disclosed heat exchangers and ridge vents; 
           [0021]      FIG. 11  is a sectional view of the bracket of  FIG. 10  incorporated into a ridge vent heat exchanger assembly according to the present disclosure; 
           [0022]      FIG. 12  illustrates a residential structure incorporating a ridge vent heat exchanger assembly and energy recovery system according to aspects of the present disclosure; 
           [0023]      FIG. 13  is a top plan view of an alternative heat exchanger assembly according to the present disclosure; 
           [0024]      FIG. 14  is a partial sectional view through an embodiment of the lateral side portion of a roof ridge vent where the material is corrugated; 
           [0025]      FIG. 15  is a partial top view of an embodiment of the lateral side portion of a roof ridge vent where the top sheet of the roof ridge vent is formed into a plurality of spaced apart protrusions defining air flow paths; 
           [0026]      FIG. 16  is a partial sectional view of the lateral side portion illustrated in  FIG. 15 , taken along line  16 - 16  thereof; 
           [0027]      FIG. 17  is a perspective view of a roll of exemplary ridge vent material compatible with the disclosed integrated ridge vent and heat exchanger embodiments; 
           [0028]      FIG. 18  is a perspective view of an exemplary ridge vent material modified according to a disclosed method; 
           [0029]      FIG. 19  is a top view of a step in a disclosed process for manufacturing an integrated ridge vent and heat exchanger; 
           [0030]      FIG. 20  is a top view of another step in a disclosed process for manufacturing an integrated ridge vent and heat exchanger; 
           [0031]      FIG. 21  is a sectional view of an exemplary ridge vent material with integral receptacles; 
           [0032]      FIG. 22  is a side elevation view of a disclosed ridge vent and heat exchanger rolled for storage and transport; 
           [0033]      FIG. 23  is a flow chart showing steps in an exemplary method for manufacturing an integrated ridge vent and heat exchanger according to aspects of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    Reference should now be made to the drawing figures, provided for purposes of illustration and not limitation, in which common reference numerals refer to similar features of the enclosed embodiments. The figures illustrate various embodiments of elongated, flexible heat exchange assemblies and such assemblies integrated with elongated roof ridge vents. The disclosed heat exchange assemblies and roof ridge vents are configured to support a plurality of heat exchange tubes directly in the flow of heated air exiting through a roof ridge vent. 
         [0035]      FIG. 1  illustrates a heat exchange assembly constructed according to aspects of the disclosure, and generally indicated by the reference numeral  10 . Heat exchange assembly  10  includes an elongated flexible support  20  constructed of air permeable material embedded in which are a plurality of heat exchange tubes  22 .  FIG. 1  illustrates a heat exchange assembly including four longitudinally extending heat exchange tubes  22  arranged in a substantially parallel, equally spaced pattern. Other numbers of heat exchange tubes  22  and other spatial arrangements are compatible with the disclosure. 
         [0036]    U-shaped connectors  24  join the four heat exchange tubes into a serpentine flow path having a length at least approximately four times the length of the heat exchange assembly  10 . Such an elongated flow path extends the time the heat collecting fluid (working fluid) is in the heat exchange tubes  22 , which are in contact with the heated air. Such an arrangement increases the quantity of energy extracted from the attic space. Heat exchange tubes  22  are preferably relatively narrow diameter to enhance the surface area of the heat exchange tubes relative to the volume of working fluid inside the tubes. One preferred heat exchange tube is approximately ½″ in outside diameter and formed from PEX, a cross-linked polyethylene, or other suitable material compatible with the liquid being handled. The working fluid used with the disclosed heat exchange assemblies is typically water or a water/ethylene glycol (anti-freeze) solution. 
         [0037]    The heat exchange tubes  22  are arranged to occupy a central portion  21  of the support  20 , with lateral portions  23  of the support  20  extending along either side of the central portion  21 . The heat exchange assembly  10  is preferably manufactured by a continuous process and cut into lengths compatible with various standard residential or industrial structures. The support  20  and heat exchange tubes are preferably constructed of plastic selected to be flexible enough that the heat exchange assembly  10  can be rolled lengthwise into a spiral roll during manufacture and bundled in this form for storage and transport. The spiral roll of heat exchange assembly  10  can be unrolled during installation on a structure. 
         [0038]    In the embodiment of  FIG. 1 , the heat exchange tubes  22  are embedded in the support  20 , which is a porous, air permeable material. Roof ridge vent material  20  is porous and intentionally configured to permit attic air to exit the attic space through a ridge vent. Suitable materials include mesh or various thermoformed, extruded, or melt-blown plastic materials. 
         [0039]      FIG. 2  illustrates the heat exchange assembly  10  of  FIG. 1  installed over a roof ridge opening  30  on a roof  32 . The heat exchange assembly  10  is covered with shingles  40  to form a cap that sheds precipitated moisture laterally onto the roof  32 . The porous, air permeable support  20  prevents the entry of insects, rodents, birds or the like. It will be noted that the lateral portions  23  of the support  20  overlap with the roof structure on either side of the roof ridge opening  30  and provide a location for attaching the heat exchange assembly to the roof  32 . The central portion  21  of the support  20  is configured to laterally span the roof ridge opening  30 . The air flow path is generally vertical through the roof ridge opening  30  into the support  20  and then laterally through the air permeable support  20 , exiting along the longitudinal sides of the heat exchange assembly  10  beneath the shingles  40  forming the cap. The support  20  is configured to maintain the heat exchange tubes  22  in a position directly in the path of heated air leaving the roof structure through the vent opening  30 . The presently disclosed embodiments are compatible with any ventilation opening communicating with a space where the opening is configured to permit the release of heated air by convection. 
         [0040]      FIG. 3  illustrates an alternative heat exchange assembly  10 ′ including four heat exchange tubes  22 ′ incorporated into an elongated support  20 ′. The heat exchange assembly  10 ′ of  FIG. 3  dispenses with the lateral side portions  23  as shown in  FIG. 1 , but is otherwise similar in construction, materials and function to the heat exchange assembly  10  illustrated in  FIG. 1 . Connectors  24  join the heat exchange tubes  22 ′ into a serpentine flow path several times the length of the heat exchange assembly  10 ′.  FIG. 4  illustrates heat exchange assembly  10 ′ installed in a roof ridge vent opening  30  in an alternative structural configuration to that illustrated in  FIG. 2 . In  FIG. 4 , the heat exchange assembly  10 ′ is installed within the roof ridge opening  30  and secured to the roof rafters  25 . Shingles  40  cover the heat exchange assembly  10 ′ to shed precipitation onto the roof  32 . Air exiting the roof ridge vent opening  30  flows vertically into the air permeable support  20 ′, past the heat exchange tubes  22 ′ and then laterally outwardly through the longitudinal sides of the support  20 ′ beneath the shingles  40  forming the cap. It will be noted that the flow area along the longitudinal sides of the arrangement illustrated in  FIG. 4  is substantially smaller than the corresponding flow area of the arrangement illustrated in  FIG. 2 . This will typically result in reduced air flow through the vent opening, with a corresponding reduction in heat transfer to the heat exchange tubes. 
         [0041]      FIG. 5  illustrates alternative heat exchanger  10 ′ installed beneath the peak of an attic roof or other space where recovery of waste heat is desired. Although the heat exchanger  10 ′ may be installed in any number of conventional ways,  FIG. 5  illustrates the assembly held in position by a series of clamping members  120  held by means of fasteners  130 , which may be nails or screws. The installation of  FIG. 5  will be significantly less efficient in collecting heat from the attic space than the installation shown in either  FIG. 2  or  4 . The installations of  FIGS. 2 and 4  position the heat exchange tubes  22 ,  22 ′ directly in contact with the flow of heated air exiting through a roof ridge vent opening  30 , while the air in the installation of  FIG. 5  will not typically have much movement. It is well known that fluid movement (flow) enhances thermal transfer by the process of convection. Convection can be natural or artificially produced by a motor driven fan or the like. In the case of the present disclosure, the various disclosed heat exchange assemblies and roof ridge vents are configured to benefit from the natural convection current in a roof structure where cool, dense air enters at the soffit vent and as it is warmed beneath the roof, expands and rises to exit through the roof ridge vent. Heat exchange installations exposed to less air flow will have less energy recovery capacity than those exposed to greater air flow. 
         [0042]    The disclosed heat exchange assemblies are designed to be integrated into an energy recovery system configured to use the heat energy collected at the roof ridge vent for other purposes.  FIG. 6  illustrates an energy recovery system  50 , into which the disclosed heat exchange assemblies  10 ,  10 ′ may be incorporated. System  50  includes a pump  60  arranged to circulate working fluid in a fluid flow loop from a heat exchanger  10 ,  10 ′ in a roof structure and a heat exchanger  62  typically located in an energy accumulator such as an insulated hot water tank. Working fluid such as a water/propylene glycol solution is circulated between the heat exchanger  10 ,  10 ′ and a second heat exchanger  62  in a closed-loop. Alternative arrangements include those where tap water is fed through a heat exchanger located in an attic space and then delivered to a hot water heater. The working fluid will typically be water or water/antifreeze solution, but can be any other liquid compatible with system materials and the purpose of heat transfer.  FIG. 6  illustrates an energy recovery system  50  in which the working fluid which has absorbed heat in the roof mounted heat exchanger  10 ,  10 ′ is circulated through heat exchanger  62  to deliver heat to a second liquid, such as domestic water. Heat exchanger  62  is typically situated in an insulated tank filled with facility domestic water. Heat recovered from the attic space by the heat exchanger  10 ,  10 ′ is delivered to the facility domestic water in the tank. Pre-heated water is thus delivered to the facility hot water generating equipment. Heat recovered according to the disclosed heat exchanger embodiments reduces the energy required to raise the domestic water temperature to the desired hot water temperature. Other heat storage media may be compatible with the disclosed heat exchangers and energy recovery systems. 
         [0043]    Alternative embodiments of roof ridge vent assemblies incorporating heat exchangers according to aspects of the present disclosure are shown in  FIGS. 7-9 . In these embodiments, heat exchange tubes  22  are not embedded in porous roof ridge vent material, but are instead situated in an open central portion  21  between the lateral side portions  23 . This configuration provides the most efficient interface between the heated air and the heat exchange tubes by limiting turbulence and thermal resistance at the interface of the heated air and heat exchange tubes  22 . In these embodiments, air flow over the heat exchange tubes  22  tends to be laminar or smooth, rather than turbulent which would be the case if the heat exchange tubes were surrounded by the porous support material. 
         [0044]      FIG. 7  illustrates an embodiment of a roof ridge vent  10  which includes a heat exchanger according to aspects of the disclosure. The roof ridge vent  10  includes a longitudinally extending top sheet  44  which may be solid or porous and is preferably constructed of a flexible plastic material. The central portion  21  of the roof ridge vent  10  is flanked by much thicker lateral side portions  23  constructed so as to permit relatively free air flow through the lateral side portions  23 . The lateral side portions  23  may be constructed of air permeable porous material, corrugated material as shown in  FIG. 14 , or constructed in the form of a plurality of spaced apart protrusions as shown in  FIGS. 15 and 16 . Plastic material is preferred for the lateral side portions because of its low cost, durability and the variety of ways in which plastic material may be formed and handled. Whatever the construction, the lateral side portions  23  must permit air flow laterally away from the central portion  21 . An air permeable scrim or sheet of mesh, screen or filter material  46  is applied along the bottom and longitudinal outside surfaces of the lateral side portions  23  to prevent ingress of wind-driven precipitation, insects, birds, rodents or the like. The lateral side portions  23  define the height of the roof ridge vent  10 , which is typically less than one inch. The lateral side portions  23  have sufficient strength to receive fasteners to attach the roof ridge vent  10  to the roof structure and to support the cap shingles. The top sheet  44  has sufficient flexibility to conform to the roof structure as illustrated in  FIG. 2 . The angle formed between the roof portions on either side of the roof ridge vent opening varies according to the pitch of the roof, which is typically between 4 and 16 inches of height per foot of horizontal spread. The materials of the roof ridge vent and the size and spacing of the heat exchange tubes are selected to ensure that the lateral side portions will conform to the shape of the roof structure, while the heat exchange tubes are maintained in a spaced apart configuration to permit air flow around the tubes. 
         [0045]    The lateral side portions  23  flank the open central portion  21  of the roof ridge vent  10 . In the disclosed embodiments, longitudinally spaced rows of receptacles  48  are configured to receive and hold the heat exchange tubes  22  in pre-determined positions with respect to each other and to the roof ridge vent  10 . The receptacles  48  illustrated in  FIG. 7  are configured to elastically deform to receive and retain the heat exchange tubes  22 . Other forms of receptacle are illustrated in  FIGS. 8 and 9 , which in all other respects are roof ridge vents similar to the roof ridge vent of  FIG. 7 .  FIG. 8  illustrates receptacles  52  having ratchet-type U-shaped fasteners which support the heat exchange tubes  22 .  FIG. 9  illustrates simple J-shaped receptacles  54  for supporting the heat exchange tubes  22 . 
         [0046]    The rows of receptacles may be integrally molded with a laterally extending plastic bracket  56  such as illustrated in  FIGS. 10 ,  11  and  13 . The bracket  56  includes a central portion  57  for supporting the heat exchange tubes  22  in spaced apart relationship and lateral side extensions  58  for attachment to the lateral side portions of the roof ridge vent  10  as shown in  FIG. 11 . The brackets  56  may be attached to the roof ridge vent  10  by adhesive, heat bonding, stapling or any fastening technique. The heat exchange tubes  22  are secured to the central portion in a generally parallel, spaced-apart configuration by J-shaped receptacles  54 . Flexible retaining posts  55  are longitudinally offset relative to the J-shaped receptacles  54 . The J-shaped receptacles  54  and retaining posts  55  are configured to deflect when a heat exchange tube is inserted between the open end of the J-shaped receptacle  54  and the retaining post  55 . Once the heat exchange tube  22  is received in the J-shaped receptacle  54 , the plastic bracket material returns to its previous configuration where the receptacle supports the heat exchange tube  22  from below, while the retaining post  55  prevents the heat exchange tube  22  from leaving the receptacle. The receptacles and retaining posts also maintain the lateral spacing of the heat exchange tubes, even when the bracket  56  is flexed to conform to the shape of a roof structure. It should be noted that the heat exchange tubes  22  are also spaced apart from the top sheet  44  of the roof ridge vent  10 , allowing air to circulate around the entire circumference of the tubes  22  as the air flows through the roof ridge vent  10 . 
         [0047]    Conventional roof ridge vent openings are typically between three and six inches in their transverse dimension, although other dimensions are possible and compatible with the disclosed embodiments. The disclosed roof ridge vent heat exchanger embodiments position a plurality of heat exchange tubes  22  in a spaced apart, generally parallel configuration and positioned between the laterally opposed air flow paths defined by the lateral side portions  23  of the roof ridge vent  10 . In this configuration, air heated in the space beneath the roof flows by convection past the heat exchange tubes  22  as it passes through the ridge vent. This convective flow of heated air over the heat exchange tubes  22  facilitates heat transfer into the working fluid within. 
         [0048]    Generally speaking, the greater the height of the space defined by the roof, the greater the speed of the convective flow through the ridge vent. This is known as a “chimney effect.” Faster flow of heated air across the heat exchange tubes generally provides greater heat transfer into the working fluid, permitting a greater rate of working fluid flow through the heat exchanger. U-shaped connectors  24  are employed to connect the heat exchange tubes into one or more serpentine flow paths extending the length of the roof ridge vent  10 . The heat exchange tubes  22  employed in the disclosed embodiments are approximately one-half inch (0.5″) in outside diameter (OD) and three-eighths of an inch (0.375″) in inside diameter (ID). The flow rate at which working fluid is circulated through the heat exchangers is calculated to maximize heat transfer while minimizing energy consumed in circulating the working fluid. Typically, this flow rate will be in the range of two to five gallons per minute (2-5 gpm). Ideally, conduits through which working fluid is delivered to the attic and retrieved to the energy storage heat exchanger  62  are insulated to retain heat recovered from the attic. 
         [0049]    Heat exchange tubes  22  may be conventional cylindrical tubes extruded from commonly used materials such as PVC or cross-linked polyethylene (PEX). Alternatively, heat exchange tubes  22  may be provided with enhanced heat transfer capability by addition of carbon fiber or other heat-conductive materials. The cross-sectional shape of the heat exchange tubes may be enhanced to further improve heat transfer. Vanes or fins may be employed on the inside surface of the heat exchange tubes  22  to modify flow of the working fluid and further enhance heat exchange. The vanes or fins may be located throughout the heat exchange tubes or located in the U-shaped connecting sections. 
         [0050]    The brackets  56  and receptacles  54  will typically be configured so the heat exchange tubes  22  do not extend beyond the thickness of the lateral side portions  23  of the ridge vent  10 , which could interfere with rolling and installation of the ridge vent. An alternative embodiment may employ flexible connectors such as tie-wraps to fix the heat exchange tubing to the hangers or protrusions descending from the top sheet. 
         [0051]    In an alternative embodiment, the heat exchange tubes may be fixed to the central portion of the ridge vent during manufacture and without the use of brackets and hangers as a separate component. The central portion of the top sheet may be configured to include a plurality of downwardly extending protrusions where a connection with the heat exchange tubes  22  can be formed. The connection between the protrusions and the heat exchange tubes  22  may be formed by heat welding, adhesive or other conventional means compatible with the manufacturing process. The ridge vent heat exchange assembly  10  is cut to standard lengths for use in construction and rolled longitudinally into a spiral roll for storage and transportation. 
         [0052]    At the job site, the ridge vent heat exchange assembly  10  is unrolled and secured spanning the ridge vent opening of a structure with the heat exchange tubes  22  exposed to the interior of the roof structure. U-shaped connectors  24  are employed to connect the longitudinal ends of the heat exchange tubes into one or more serpentine flow paths. Installation of the roof ridge vent heat exchange assembly  10  is essentially without cost, because the heat exchange assembly is integrated into a convenient to use and conventional roof ridge vent. Installation of the connectors and working fluid supply lines can be accomplished very inexpensively with push-on Sharkbite-type fittings. 
         [0053]    The roof ridge vent heat exchange assembly  10  is then connected to a storage heat exchange assembly  62  positioned in a water tank  64  as shown in  FIG. 12 . Temperature sensors T 1  and T 2  detect the temperature in the attic space or the temperature of the working fluid in the heat exchanger  10 , and storage tank, respectively. Thermostatically controlled switches are used to activate a circulating pump  60  to circulate the working fluid between the roof-mounted heat exchanger  10  which absorbs heat from the roof space and the storage heat exchanger  62  which transfers heat to water in the storage tank  64 . A controller is typically provided to detect the temperature signals generated by sensors T 1  and T 2  and activate the pump  60  when T 1  is sufficiently greater (ΔT) than T 2  to indicate that energy transfer is warranted. The storage tank  64  includes a heat exchange coil (storage heat exchanger  62 ) of known construction and is insulated to contain the heat extracted from the roof space. Alternative embodiments may circulate excess heat to pools, spas or heating systems where appropriate. 
         [0054]      FIG. 13  illustrates an alternative heat exchanger  80 , which includes heat exchange tubes  22  and a plurality of brackets  56 . In this heat exchanger  80 , heat exchange tubes  22  are suspended in the path of air leaving roof ridge vent opening and the side extensions of the brackets are attached to the roof structure along either side of the opening. This heat exchanger  80  is compatible with other forms of ridge vent and can be installed independent of the ridge vent. 
       Methods of Manufacture 
       [0055]    Several methods of manufacture for the disclosed integrated roof ridge vent and heat exchange assembly will now be described with reference to  FIGS. 17-23 . Manufacturing methods for elongated heat exchange assemblies for heat recovery and compatible with elongated vents in structures will also be described. 
         [0056]    The basic components of the disclosed integrated roof ridge vent and heat exchange assembly include: ridge vent material  90 , supports for heat exchange tubes, heat exchange tubes  22  and various fluid couplings  24 ,  82 . As described, the ridge vent material  90  is a flexible material configured to laterally span an elongated vent opening. The ridge vent material  90  is flexible in the longitudinal and lateral directions, permitting the ridge vent and heat exchange assembly to be rolled longitudinally for storage and shipping as well as to conform to the roof structure on either side of the vent when installed. One function of the ridge vent material is to support a cap above the surrounding roofing material. The ridge vent material defines air flow paths along either side of the ridge vent beneath the cap. A further function of the ridge vent material is to prevent the intrusion of insects, pests, debris or weather driven water into the structure. 
         [0057]    Suitable materials for the body of the disclosed ridge vent include molded, extruded or thermoformed plastic materials, melt-blown plastic materials, woven or nonwoven fabric materials, open cell foam materials, mats of natural fibrous material such as coconut fiber and various combinations thereof. According to a preferred embodiment of the disclosed roof ridge vent heat exchange assembly, the ridge vent material  90  is prepared with lateral side portions  23  having a height between top and bottom surfaces along either side of a central portion  21  with a reduced height relative to the lateral side portions  23  as shown in  FIGS. 7 ,  8 ,  9 ,  11  and  17 . The ridge vent material  90  may be fabricated with this configuration or various manufacturing methods may be employed to create a central portion having a reduced height relative to the lateral side portions. Preferred embodiments of ridge vent material include screen, fabric or nonwoven fibrous sheets at the outer longitudinal edges to prevent intrusion of insects and debris. 
         [0058]    According to a disclosed manufacturing method, ridge vent material  90  having a substantially constant height across its width is modified by application of heat and pressure to a central portion of the ridge vent material as shown in  FIG. 18 , thereby permanently deforming or compressing the central portion  21  to provide a reduced thickness relative to the lateral side portions  23 . As shown in  FIG. 17 , a heated wheel  92  is used to compress a plastic ridge vent material. The reduced thickness of the central portion  21  defines an elongated channel to accommodate the heat exchange tubes  22  in a substantially parallel, spaced apart configuration. It is useful to place the heat exchange tubes  22  between the lateral side portions  23  and within the height of the assembly because the space beneath the vent opening is typically interrupted by trusses or other structural members. 
         [0059]    An exemplary manufacturing method is illustrated in  FIGS. 17-23 . Once a suitable ridge vent material  90  has been selected and prepared (if necessary), the ridge vent material is cut to a selected, predetermined length. A typical ridge vent for residential construction is 40 feet or less, so a common length for the ridge vent heat exchange assembly will be approximately 40 feet. The selected length of ridge vent material is laid out on a suitable support surface  100  as shown in  FIG. 19 , such as a manufacturing table, with the reduced thickness central portion  21  of the ridge vent material  90  facing upward. 
         [0060]    If the ridge vent material  90  does not already have receptacles  48  for receiving the heat exchange tubes, then the next step is to form the receptacles on the ridge vent material. This can be accomplished by further modifying the ridge vent material itself, or by securing additional components to the ridge vent material. In a preferred embodiment, a plurality of brackets  56  such as those shown in  FIGS. 10 and 11  are secured to the ridge vent material  90  by fasteners  94  such as staples or other means including heat bonding, adhesive or the like. The bracket  56  has a cross-sectional shape complementary to the sectional shape of the ridge vent material  90  as shown in  FIG. 11  and includes a bracket central portion  57  extending into the reduced thickness central portion  21  of the ridge vent material  90 . The bracket central portion  57  includes a number of receptacles  54 ,  55 , each configured to receive and retain a heat exchange tube  22 . The receptacles  54 ,  55  are configured to support the heat exchange tubes  22  in a substantially parallel, laterally spaced configuration which permits air flow between and around the heat exchange tubes. The brackets and receptacles are also configured to maintain the heat exchange tubes  22  spaced from the upper limit of the central portion  21  of the ridge vent material  90  so that air may flow above the heat exchange tubes  22  as well as between them. Various receptacle configurations are disclosed in  FIGS. 7-11 , any of which are compatible with the disclosed manufacturing methods. Generally speaking, the receptacles  48  are configured to allow simple installation of the heat exchange tubes  22  by press fit without the use of tools. The receptacles are configured to accommodate longitudinal movement of the heat exchange tubes relative to the brackets and receptacles to allow for thermal expansion and adjustments during packaging, shipping and installation. 
         [0061]    In an alternative embodiment, the roof ridge vent material may be prepared with integral receptacles molded or formed into the central portion of the ridge vent material as shown in  FIG. 21 . In such an embodiment, the step of forming the supports/receptacles for the heat exchange tubes  22  is performed simultaneously with preparation of the ridge vent material  90  and eliminates the need for a separate step. Various methods of preparing suitable ridge vent material  90  with integral receptacles  48  for heat exchange tubes  22  will occur to those skilled in the art. Extrusion, thermal forming and formations of melt-blown plastic fibers may be employed to provide the integral supports for the heat exchange tubes. As shown in  FIG. 21 , the receptacles define openings that surround more than half the circumference of the heat exchange tubes  22 , so the tubes can be press fit and retained without additional fasteners or tools. 
         [0062]    Once the ridge vent material  90  is cut to length and positioned so that the receptacles are accessible, the next step in the method is to attach a plurality of heat exchange tubes to the ridge vent material. Heat exchange tubes  22  of a selected material and diameter are cut to a length somewhat longer than the length of the ridge vent material  90 . This additional length accommodates some adjustments and attachment to fluid couplings necessary to integrate the assembly into an energy recovery system such as that shown in  FIGS. 6 and 12 . Disclosed embodiments include four heat exchange tubes  22  of a selected diameter, though other numbers of heat exchange tubes of varying diameters are also compatible with the disclosed assemblies. The heat exchange tubes  22  are cut to length and press fit into the receptacles as shown in  FIG. 22 . Each tube  22  has open longitudinal ends, with the result that each end of the assembly at this stage of manufacture includes four heat exchange tubes  22 , each with open ends at both longitudinal ends of the assembly. 
         [0063]    The next step in the disclosed method of manufacture is to attach fluid couplings  24 ,  82  to the open longitudinal ends  84  of the heat exchange tubes  22 . Some of the fluid couplings are configured to fluidly connect two of the heat exchange tubes  22  to define an extended fluid flow pathway traversing the length of the assembly more than once. One preferred configuration includes two U-bend shark-bite type connectors  24  extending between adjacent open longitudinal ends of the heat exchange tubes at one end of the assembly as shown in  FIG. 24 . The opposite end of the assembly connects alternate open longitudinal ends to a three-way connector coupling  82 , such as a T or a Y to define a fluid inlet and outlet connected to two fluid flow pathways. The diameter of the tubes and couplings are selected to provide a fluid flow pathway of a particular predetermined capacity having predetermined flow properties. For example, the Y or T connectors are selected with a fluid inlet and outlet diameter larger than the diameter of the heat exchange tubes to which they are connected. In the context of the disclosed embodiments, the heat exchange tubes have an inside diameter of approximately ⅜″ (0.375″) and the Y or T connectors have an inlet/outlet opening with an inside diameter of approximately ¾″ (0.75″) or approximately double the flow area of the heat exchange tubes  22 . This configuration permits a greater volume of fluid to be divided between connected heat exchange tubes resulting in the desired fluid flow through the heat exchange assembly. Once the appropriate fluid couplings are connected to the heat exchange tubes, the ridge vent heat exchange assembly is tested and inspected. Alternatively, all the heat exchange tubes  22  may be coupled into a single flow path by installation of U-bend connectors between adjacent heat exchange tube open ends  84  as shown in  FIG. 3 . Heat exchange tube diameters, number of heat exchange tubes, length of flow path and the flow rate of working fluid through the heat exchanger are selected according to known thermodynamic principals to maximize heat/energy recovery while minimizing energy consumption required to circulate the working fluid. 
         [0064]    The completed ridge vent and heat exchanger assembly  10  is rolled longitudinally into a compact spiral configuration as shown in  FIG. 22  and secured in a rolled bundle for storage and transportation to the construction site. At the construction site, the spiral bundle is opened and the ridge vent and heat exchanger assembly  10  is unrolled with the heat exchange tubes facing upwardly. The assembly is then flipped over into position spanning the vent opening and secured to the roof structure through the lateral side portions  23  of the assembly. Roofing material is secured over the top of the ridge vent heat exchange assembly according to relevant building codes. The fluid inlet and outlet couplings IN, OUT are connected to an energy recovery system so that heat collected in the heat exchange tubes  22  is conveyed to an energy storage device such as a hot water tank or used for other purposes as describe above and illustrated in  FIGS. 6 and 12 . 
         [0065]    An alternative heat exchange assembly  80  is illustrated in  FIG. 13 . This heat exchange assembly includes only support brackets  56 , a plurality of heat exchange tubes  22  and appropriate fluid couplings  24 ,  82 . Manufacture of this assembly begins by laying out a suitable number of support brackets on a support surface  100 . The number of brackets  56  is dependent upon the length of the desired heat exchange assembly and the space between the brackets over the length of the assembly. The brackets are configured to suspend the heat exchange tubes  22  over an elongated vent opening in a structure as discussed above. The brackets  56 , heat exchange tubes  22  and fluid couplings are configured, assembled and operate in a manner substantially the same as the same components discussed above with respect to the integrated roof ridge vent heat exchange assembly  10 . This alternative embodiment  80  is employed where the roofing system includes its own ridge vent, such as in a tile or metal roof system. The heat exchange assembly  80  is installed beneath the metal or tile roof system spanning the vent opening and the roof system is completed over the installed heat exchanger  80 . 
         [0066]    In the embodiments described above, it will be recognized that individual elements and/or features thereof are not necessarily limited to a particular embodiment but, where applicable, are interchangeable and can be used in any selected embodiment even though such may not be specifically shown. 
         [0067]    Spatially orienting terms such as above, below, upper, lower, inner, outer, inwardly, outwardly, vertical, horizontal and the like when used herein refer to the positions of the respective elements shown on the accompanying drawing figures and the present invention is not necessarily limited to such positions. 
         [0068]    It is also to be understood that the following claims are intended to cover all the generic and specific features of the disclosed embodiments and all statements of the scope of the embodiments which might be said to fall within the words of the claims.