- BACKGROUND OF THE INVENTION
This Application claims the benefit of Provisional Application No. 60/943,076, filed on Jun. 11, 2007.
1. Field of the Invention
This invention relates to the recirculation and ventilation of roof top heated air in residential and commercial buildings. The present invention may be utilized in both pre-existing buildings as well as incorporated into new construction. In general, the present invention provides means to capture and control heat generated within a structure, and more specifically the heated air that collects underneath a roof due to natural processes and/or the heated air that collects underneath a roof due to design features incorporated into a building's structure.
Heated air within a building rises; a natural result of this convective flow causes heated air to collect at or near the underside of the peak of the structure. Adding to the temperature rise under the roof structure is the effect of sunlight on a roof. In particular, sunlight on the surface of a roof, and in particular on roof shingles, causes an increase in the temperature of the air underneath the roof surface. This accumulation of additional heat, in addition to being of waste of available energy, causes degradation of the structure of a roof and increases the rate of deterioration of roof shingles.
A partial solution to this collected heat problem is the addition of an attic vent or a roof peak vent to a structure. Venting of the air adjacent to the underside of a roof helps to reduce the temperature of the roof structure itself. Modern buildings incorporate a further design feature: air spaces located within the structure of the roof, under the shingles and sheathing and above the insulation layer. This design feature, however, relies upon unassisted convective flow, and is intended to vent any such heated air to the atmosphere. Generally, such a design works in conjunction with a roof cap for the purpose of venting the heated air outside of the structure. And, while the roof cap vent and air spaces under the shingles and sheathing of a roof provide cooling means for the roof, heat is constantly being generated on the surface of a roof. Therefore, except for unassisted natural mechanisms that remove heat from the surface of a roof, the present designs rely upon heat removal mechanisms several layers removed from a significant source of the heat sought to be removed. Heat resident for any period of time under the sheathing and shingles has a greater opportunity for movement into the remainder of the structure.
Overall, this means that present designs have two major flaws. First, they are inherently inefficient and rely upon purely passive mechanisms for heat transfer and cooling of the affected roof structure. Second, the present designs waste significant heat energy that may be recaptured and utilized within the structure itself, reducing overall heat loss within the structure. What is needed is a method of enhancing the cooling of a roof structure while providing the option of simultaneously supplementing a building's heating system.
It therefore an object of the present invention to reduce the amount of heat that normally collects in, under and above roof structures and that contributes to the deterioration of roof shingles and may be conveyed through the insulation into the interior of the building structure. It is a further object of the present invention to provide an efficient manner by which to supplement the heating system of a building. It is yet another object of the present invention to provide a device that comprises an air capture and circulation system wherein a roof cap structure, vent, heated air collecting panels, and circulation devices are used in combination to prevent heated air rising from the eaves to the ridge during winter months from escaping into the atmosphere, and to channel that heated air from the ridge area to the primary heat source where it is either blown into the supply duct directly into the building structure or into the primary heat source's air intake.
2. Description of the Prior Art
Various methods have been used both to ventilate the area beneath roof structures, and to recirculate the air beneath roof structures through air circulation systems. These methods have been primarily intended to prevent the accumulation of heated air in the attic area during summer months and to employ the attic heat in the winter to improve the heating efficiency of buildings. Typically these methods involve air circulation systems wherein devices, such as fans and blowers, are intended to supplement and/or assist the passive heat transfer that occurs as a result of building design. Such methods are generally configured to draw warm air from the attic area into the atmosphere during the summer months and, alternatively, from the lower part of the interior of a building structure to the upper portion thereof during the winter months. The methods employed are varied, and include the use of combinations of air ducts, valves, and blowers, such as the air duct assembly taught in U.S. Pat. No. 3,463,391 (Air Duct Assembly Particularly For A Stable or The Like) (the '391 Patent) to Haegens.
The '391 Patent teaches an air duct assembly, particularly for use in stables and similar building structures, that works to stabilize and maintain the interior temperature of the buildings, namely by replenishing air into the buildings and removing warm air therefrom and, alternatively, by recirculating warm air in the stable. The air duct assembly of the '391 Patent extends through the roof and allows the influx of outside air into the structure and the outflow of warm air from inside the structure to the outside. While this patent utilizes a fan mechanism and valves to control the flow of air as in the current invention, the '391 Patent has duct openings located in the center of the structure ('391 Patent, column 2 lines 17-21) to draw in heated air. More importantly, that heated air is not recirculated as in the current invention, but is vented to the outside of the structure ('391 Patent, column 4, lines 2-3).
Another such method, U.S. Pat. No. 3,653,316 (Industrial Building Design) (the '316 Patent) teaches an industrial building utilizing an interior powerplant exhaust stack in combination with air blowers and ducting, as a means to heat air for the building. The '316 design allows for recirculation of heated air, but requires that the overall design of the building house the recirculation and heating systems within the center stack of the building, described as a circular dome structure with a central support column. As distinguished from the current invention, the '316 Patent does not address the type of heating and cooling efficiency problem addressed in the current invention.
U.S. Pat. No. 5,031,514 (Apparatus and Method For Controlling The Mixing of Atmospheric Air From A Building) (the '514 Patent) teaches “an apparatus for controlling the mixing of atmospheric air with return air from a building.” The '514 invention consists of an external housing unit that is secured to a roof and includes baffles and dampers to mix atmospheric air with return air from a building. However, the device is specifically designed to re-mix return air from return air ducting and is unsuited to the heating/ventilation problem addressed by the current invention. U. S. Pat. No. 6,147,295 (Sunlight Energy Conversion Apparatus, and Air Circulation System) (the '295 Patent) teaches a means to maintain the temperature of a solar energy conversion panel within a high enough range to allow continued operation of the solar panels. The '295 invention utilizes ducting to provide an air-flow space underneath the roof of a structure; however, the air flow from the building is used to warm the solar panels mounted on the roof of the structure, and warm air (during summer operation) is then vented outside of the structure. Cool air is drawn in from the outside during winter operation, is heated and then supplied to the building structure ('295 Patent, column 4, lines 64-67). Neither the '514 Patent nor the '295 Patent utilizes the heated air recirculation means as set forth in the current invention.
Finally, U.S. Pat. No. 3,683,785 (Roof Construction Providing Air Flow From Eave To Ridge) (the '785 Patent), teaches a roof ventilation system to allow air flow on the underside of the roof. The stated object of the design is to remove the thermal gradient between the surface of the roof and the underside of the roof to prevent ice buildup from water runoff. While the '785 invention makes use of air flow under the roof structure, it does not make use of the warm air to recirculate back to the lower portions of the building. The invention does serve, however, to help remove accumulated warm air in the attic ('785 Patent, column 4, lines 43-47), but does not recirculate any of that accumulated warm air.
The current invention is an improvement over the prior art in that it provides a new means by which heated air that accumulates in the roof structure of buildings is captured within a roof cap structure and then circulated into the primary heating cycle of a building structure during winter months, thereby increasing the efficiency of the heat system. The present invention assists and enhances the passive air flow that results from building designs. In another embodiment, the present invention also provides heat collecting panels to be used during winter months to increase the amount of heated air available to direct into the primary heating system of the building structure. As an added benefit, during the summer months the current invention permits the discharge of heated air that rises to the crown from the roof area to the outside. The current invention does not require a particular building design and conveniently may be secured atop an existing roof cap, utilized to replace an existing roof cap altogether, or used in new construction.
It is an object of the present invention to provide means to reduce heat losses in a structure to the atmosphere.
It is a further object of the present invention of recirculating recaptured heated air that otherwise would be a loss to the heating system for a structure.
It is yet a further object of the present invention to provide a means to supplement the heating system of a structure through the capture of air at the surface of a roof heated by solar energy.
It is yet a further object of the present invention to provide a means to reduce heat damage to roof structures.
- SUMMARY OF THE PRESENT INVENTION
It will be understood by those skilled in the art that the invention as disclosed below is merely illustrative and that there are other embodiments that are not described herein that still fall within the scope and intent of the present invention. In particular, it will be obvious to one skilled in the art that the method of pushing air through the roof cap structure may be accomplished using a variety of air circulation devices. Further, the method of controlling the direction of the heated air, whether to send the heated air into the ambient environment or to direct it back into the heating system of the building, can be accomplished in a multitude of ways. The method of using a pneumatic valve that may be electronically controlled by a person or by an automatic temperature control system is disclosed herein as the means to accomplish this task but should not be deemed as a limit on the scope of the present invention.
The present invention relates to a rooftop device designed to recirculate heated air and to direct the same into the primary heating cycle of a residential or commercial building. In a first embodiment, the rooftop device disclosed herein is utilized in conjunction with conventional roof construction of buildings, and comprises (i) a roof cap structure that either is placed on top of an existing roof cap, utilized to replace an existing roof cap, or built into new construction and (ii) circulation devices and air flow direction control devices that allow for the capture of heated air that is generated or collects under the roof structure of a building, and the subsequent movement of the heated air to accomplish either venting of the heated air to the atmosphere or circulating the captured air into the heating system of the structure. The present invention, through such design, provides a method to carry captured heated air to the primary heat source of the building structure during winter months and/or to discharge heated air to the atmosphere during the summer months.
In another embodiment, the present invention further comprises substantially transparent panels that are affixed to the roof surface and secured thereto, the transparent panels creating air passages between the panels and the surface of a roof. The air passages communicate with a roof cap.
DESCRIPTION OF THE DRAWINGS
In another embodiment, the transparent panels incorporate openings distal to the peak of the roof of a structure.
FIG. 1 is a view of a building incorporating the present invention.
FIG. 2 is an end view cross section illustrating the roof cap and air circulation patterns of the present invention.
FIG. 3 is an end view cross section of the vent and air circulation of the present invention.
FIG. 4 is an isometric view of the roof panels and air circulation of the present invention.
DESCRIPTION OF A PREFERRED EMBODIMENT
FIG. 5 is a detailed view of fan, valve assembly and air circulation of the roof cap and vent of the present invention.
Referring now to FIG. 1 and FIG. 2, both illustrate air flow direction by arrows. FIG. 1 is a side view of a structure 100 is shown incorporating the present invention. The panels 101 are located above the surface of the roof 106. The panels 101 and the surface of the roof 106 form air passages 205 wherein air is trapped, heated and circulated to the roof cap 102. It will be understood by those skilled in the art that, while numerous materials may be utilized for the panels 101, such as glass or plastic, it is preferred that lightweight transparent materials, such as Plexiglas® and the like, form the basis of the panels 101. FIG. 1 illustrates three panels 101 stretching across one side of the roof 106 of a typical house, but it will be understood that the number and size of panels 101 may vary depending upon the size and shape of the roof 106 surface of a structure 100, and such variations in the size and shape of the panels 101 will not result in deviation from the invention as described herein.
Air within the space between the panels 101 and the surface of the roof 106 increases in temperature as a result of sunlight striking the roof 106. As the panels 101 heat up, the air within heats up and rises towards the top ridge of the roof 106. The panels 101 create passages 205 between the surface of the roof 106 and the underside of the panels 101; the noted heated air collects within these passages 205. The passages 205 created by the panels 101 and the roof 106 surface communicate with the air passage 109 within the roof cap 102 through inlet means 110 in the roof cap 102. The inlet means may comprise openings, baffled or controlled openings, and the like. The panels 101 further comprise openings 108 distal to the peak of the roof 106. Natural convective flow causes the heated air to flow into the roof cap 102. A fan 111 located within the roof cap 102 assists the air flow from the passages 205. The roof cap 102 further communicates with the air spaces 204 located under the roof 106. The air spaces 204 are designed in new construction to be located between the roof 106 sheathing 201 and the insulation layer 202.
The fan 111 causes heated air to be drawn through the air passage 109 within the roof cap 102 in the direction of the fan 111, and thereafter into a vent 103. The vent 103 comprises a air passage 105 and valve 112. The valve 112 located within the vent 103 may be positioned to vent 103 heated air to the atmosphere (as shown in FIG. 1), positioned to direct heated air back into the building 100 air handling system 104, or may be positioned in such a manner that the heated air directed to the vent 103 is partially vented and partially redirected into the building 100 air handling system 104. It will be understood by those skilled in the art that the valve 112 may be adjusted by means well known in the art to a intermediate position allowing control over the volume of air flow in either direction within the vent 103.
The present invention is described as installed onto existing structures or incorporated into new construction wherein the air under the roof 106 is intended to be vented at the peak of the structure 100. It will be understood by those skilled in the art, however, that heat generated within a structure 100 may be vented at various points on the structure 100 and, consequently, the present invention may capture that heated air at the point of venting of the structure 100 without deviating from the scope and intent of the present invention. For example, the point of venting could be located at some specific point below the peak of the roof 106, and such vent 103 outlet may be located in such a manner as to vent 103 heated air directly into the passage 205 between the roof 106 and the panels 101.
FIG. 3 illustrates a cross section view of the vent 103 portion of the present invention. The rooftop air recirculation device will enable the heated air to be released through the vent 103 in warmer months or, alternatively, recirculate the heated air to the intake of the building heating system in the colder months. The arrows on FIG. 3 show flow paths of heated air, with air either vented to the atmosphere 301, directed 302 to the structure's air handling system 104, or a combination thereof.
FIG. 4 illustrates a rooftop assembly incorporating two panels 101 joined at a centerline 402. The rooftop assembly is supported by braces 401. The braces 401 are preferentially “Z” shaped when viewed on end, and support the panels 101 at both joint areas (represented by the centerline 402 in FIG. 4) and the ends of the rooftop assembly. Each panel 101 forms a closed structure 100 with the roof 106, with the exception of openings 108 at the end distal to the roof 106 peak, and inlet means 110 proximal to the roof 106 peak. The resulting structure 100 forms a passage 205 between the panels 101 and the roof 106. Air within the passage 205 is warmer than external ambient air as a result of heated air collecting under the roof 106 as well as sunlight on the surface of the panels 101.
Referring now to FIG. 5, heated air flows to the vent 103 as a result of natural convection, the flow of air caused by the fan 111, or a combination of the two. The valve 112 may be rotated about a horizontal axis 501 such that air may be either vented up to the atmosphere or down to the building's air handling system 104.