Method for Manufacture of Integrated Ridge Vent and Heat Exchanger
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.
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.
The present disclosure relates to roof vents generally and more particularly to a method for manufacture of an integrated ridge vent and heat exchanger.
BACKGROUNDStructures 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.
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.
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.
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.
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.
SUMMARYA 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.
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.
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.
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.
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.
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.
In the embodiment of
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.
Alternative embodiments of roof ridge vent assemblies incorporating heat exchangers according to aspects of the present disclosure are shown in
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
The rows of receptacles may be integrally molded with a laterally extending plastic bracket 56 such as illustrated in
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.
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.
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.
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.
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.
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.
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
Several methods of manufacture for the disclosed integrated roof ridge vent and heat exchange assembly will now be described with reference to
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.
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
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
An exemplary manufacturing method is illustrated in
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
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
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
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
The completed ridge vent and heat exchanger assembly 10 is rolled longitudinally into a compact spiral configuration as shown in
An alternative heat exchange assembly 80 is illustrated in
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.
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.
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.
Claims
1. A method of manufacture for an integrated roof ridge vent and heat exchanger assembly comprising:
- providing an elongated flexible support of indeterminate length, said support having a central portion between lateral side portions, said central portion having a predetermined lateral span and said side portions having a first thickness between a top surface and a bottom surface and defining an air flow path between said top and bottom surfaces, said air flow path permitting air to pass through said elongated flexible support in a direction transverse to the length of said support;
- cutting said elongated flexible support to a predetermined length;
- forming a plurality of supports in said central portion;
- securing a plurality of flexible heat exchange tubes to said supports, said heat exchange tubes and said supports arranged to maintain said heat exchange tubes spaced apart from each other and from said support to permit air flow between and around said heat exchange tubes before the air flow enters said air flow path, said heat exchange tubes having open longitudinal ends;
- attaching a plurality of fluid couplings extending between the open longitudinal ends of adjacent heat exchange tubes to connect said plurality of heat exchange tubes into at least one fluid flow path having a fluid flow path length at least twice said predetermined length;
- rolling said integrated roof ridge vent and heat exchanger lengthwise and securing said rolled integrated roof ridge vent and heat exchanger in said rolled configuration.
2. The method of claim 1, wherein said step of securing comprises:
- mounting a plurality of brackets to said support at predetermined positions along said predetermined length, each said bracket including attachment wings and a tubing support portion intermediate said attachment wings, said attachment wings secured to said lateral side portions with said bracket substantially perpendicular to said predetermined length and said tubing support portion located in said central portion of said support.
3. The method of claim 1, comprising:
- forming said support with a central portion having a second thickness less than said first thickness.
4. The method of claim 3, wherein said step of forming comprises:
- constructing said support of material which deforms under heat and pressure;
- applying heat and pressure to said support central portion to compress said support to define said reduced thickness central portion relative to said lateral side portions.
5. The method of claim 1, wherein said step of attaching comprises attaching fluid couplings to the open ends of alternate said heat exchange tubes opposite said fluid couplings to define a plurality of fluid flow paths, said fluid flow paths communicating with a common input and output.
6. The method of claim 2, wherein said step of mounting comprises:
- fixing said brackets to said support using fasteners, adhesive, or heat bonding.
7. The method of claim 1, wherein said step of providing and forming comprise:
- fabricating said support to include a central portion having a second thickness less than said first thickness and including longitudinally extending rows of laterally separated seats configured to receive said heat exchange tubes and said step of securing comprises:
- fixing each of said heat exchange tubes to respective of said rows of seats so that said heat exchange tubes are held in laterally spaced relation to each other.
8. The method of claim 1, wherein said step of securing comprises:
- securing an even number of heat exchange tubes to said supports; and said step of attaching comprises:
- attaching U-bend fluid couplings between the open longitudinal ends of adjacent heat exchange tubes at a first longitudinal end of said assembly and connecting alternate open longitudinal ends of said heat exchange tubes in fluid communication with each other and with a fluid inlet or outlet at a second end of said assembly so that pairs of said heat exchange tubes define a fluid flow path between said fluid inlet and said fluid outlet.
9. A method for manufacturing an elongated heat exchange assembly for attachment to a structure defining an interior air space and including an elongated vent opening having a known length and width communicating with the interior air space to permit air within the interior space to exit the interior space through the vent opening by convection, said method comprising:
- providing one or more supports, each support including a central section between a pair of outer sections, said central section configured to span the width of the vent opening and said outer sections attachable to the structure on either side of the vent opening;
- cutting a plurality of continuous, flexible, heat exchange tubes to a first length substantially equal to the length of the vent opening, each of said heat exchange tubes having open longitudinal ends;
- attaching at least two of said plurality of heat exchange tubes to said one or more supports, said heat exchange tubes engaged with the central section of said one or more supports at predetermined intervals along the length of said heat exchange tubes to maintain said heat exchange spaced from each other across said central section to permit air flow between said heat exchange tubes;
- joining at least one fluid coupling to the open longitudinal ends of said heat exchange tubes to define a fluid flow path having a length at least as long as the vent opening;
- rolling the heat exchange assembly lengthwise; and
- securing the rolled heat exchange assembly in the rolled configuration.
10. The method of claim 9, wherein said step of joining comprises:
- selecting said fluid couplings to connect adjacent heat exchange tubes into a fluid flow path having a length at least twice the length of the vent opening.
11. The method of claim 9, wherein said step of joining comprises:
- selecting said fluid couplings to join a plurality of heat exchange tubes to define a fluid flow inlet; and
- selecting said fluid couplings to join a plurality of heat exchange tubes to define a fluid flow outlet;
- said fluid flow path extending between said fluid flow inlet and said fluid flow outlet.
12. The method of claim 9, comprising
- securing said at least one support to a longitudinally extending, flexible ridge vent, said ridge vent including lateral side portions overlapping with said outer sections and defining an air flow path substantially perpendicular to the length of said assembly; and
- rolling the resulting assembly longitudinally.
Type: Application
Filed: Apr 1, 2010
Publication Date: Oct 28, 2010
Applicant: GREENWARD ALTERNATIVES LLC (Willimantic, CT)
Inventors: Bill G. Ward (North Windham, CT), Peter E. Kegler (Chaplin, CT), Peter T. Poulos (Willimantic, CT), John S. Federowicz (Mansfield, CT), Theodore Poulos (Thiells, NY), Kevin B. Scott (Harrison, NY)
Application Number: 12/752,716
International Classification: B21D 53/02 (20060101);