1. Field of Invention
The Air Barrier invention relates generally to a system for minimizing the heat transfer through structural openings in residential and commercial construction where the closures of those structural openings are formed with an interior panel, an exterior panel and an air gap in between the interior and exterior panels, such as windows with storm windows, doors with storm doors, or skylights. Minimizing the heat transfer through these closures of structural openings reduces the load on heating and cooling systems. More specifically it involves moving an almost constant temperature air through a gap between an outside panel and an inner panel. The moving air is held at a nearly constant temperature by cycling it through a heat exchanger which can be either a water to air system using well water at approximately 55 degrees Fahrenheit or an air to air heat exchanger blowing air through an underground thermally conductive tube of sufficient depth and length to offset temperature fluctuations that the moving air experiences as it travels through the closed system in insulated tubing.
2. Prior Art
Many attempts have been made to minimize the heat transfer through windows which typically accounts for the largest heat loss or gain in a normally insulated structure. Windows have the lowest thermal resistance or R-value of any standard building materials. Typically a 2×6 inch wall construction with R-19 fiberglass insulation has an R value of approximately 11.7 where a single pane glass window has a thermal resistance or R-value of 0.9. The addition of a second glass was tried, as in the storm window approach, to reduce that loss or inhibit that heat transfer. Two and three pane thermopane approaches were used in conjunction with storm windows with an air gap between the thermopane and the storm windows. Although static air is a good insulator, over time the temperature of trapped air inside the storm window gradually attains the temperature of the exterior air such that the temperature differential between the interior of the structure and the outside of the interior panel is the same as between the interior and the exterior temperature. The heat loss or transfer through a given opening is equal to the thermal conductivity of the materials in the closure times the area of the closure times the temperature differential between the interior and the exterior surface of the interior panel. To improve the thermal resistance of the gap between the windows, gasses with lower thermal conductivity than air such as argon, krypton and xenon were placed between the layers. These gasses are more expensive and tend to leak out over time with high replacement costs and fairly short life spans. The best Insulator for the gap is a perfect vacuum, but this puts a significant strain on the glass reducing the allowable span between supports and requires even more expensive seals. When the seal eventually fails it draws moisture into the space between windows clouding the visibility. Various coatings with different reflectivity and emissivity have also been proposed but add to the costs and some have negative impacts on visibility.
To date the prior art attempts to resolve this problem have been minimally effective but costly.
The Air Barrier System utilizes a constant temperature air moving through the gap between an exterior panel and an interior panel. The interior panel and the exterior panel are separated by a spacer frame on each side, top and bottom and have air flow ports top and bottom to supply the moving air at the top or bottom depending on the ambient temperature. If heating is required, the constant temperature air source supplies air to the top port and is drawn off through the bottom port and returned to the constant temperature air source. If cooling is desired, air flow is reversed putting constant temperature air in to the bottom port from the constant temperature source and drawing it off through the top port to return to the constant temperature source. A plurality of structural opening closures can be hooked to a closed loop system with insulated tubing run from the constant temperature source to the top port of each closure, until the distal closure where the constant temperature air source is capped with a top line plug. The proximal end of the constant temperature return is capped with a bottom line plug and the successive bottom ports are connected with insulated tubing to the constant temperature air return which is returned with insulated tubing back to the constant temperature source. The top and bottom ports have openings to the gap between the exterior panels and the interior panels.
Constant temperature air may be provided by a heat exchanger outlet from either a water-to-air system or an air-to-air system or any other source that can provide a constant low velocity flow of regulated temperature air. The water to air system would consist of flowing well water through the heat exchanger, providing a nearly constant 55 degree Fahrenheit air stream to the ports. Blowing air through a sufficient length of conductive tubing buried deep enough in the ground to provide a similar constant temperature output to the ports is also possible
In order that the invention is fully understood it will now be described with reference to the following drawings in which:
Building, power source, solar collectors, and energy storage devices are shown in broken lines, as they are not part of this invention but shown for illustrative purposes only.
The same reference numbers will be used throughout this application for the same and like features.
In order that Air Barrier System 10 is fully understood it will now be described by way of the following example. This new invention is a convenient and easily adaptable system for inhibiting the heat transfer through closures of structural openings in a wall. Air Barrier System 10 functions by pushing and pulling a stream of constant temperature air 42 through gap 26 between an exterior panel 24 and an interior panel 28. Panels 24 and 28 can be made from various materials and be composed of one or more layers or panes. Air Barrier System 10 utilizes closure 18 with top port 32 and bottom port 48, with a minimum of two panels 24 and 28 separated by spacer frame 30 around the panel sandwich as shown in
Pumps, fans, solar collectors, and energy storage devices are not part of this invention and are shown for illustrative purposes only. Air-to-air and water-to-air heat exchangers 46 and 12 are shown as possible sources of constant temperature air 42. It does not need to be heated or cooled to fall well below the expected maximum temperature environment of 120 degrees Fahrenheit and well above the minimum expected temperature environment of −30 degrees Fahrenheit. This minimizes the temperature differential to the interior of the structure. In prior art trapped stationary air insulated gaps, conduction occurs between the external air, through the exterior panel 24 and into the trapped air gap 26 until the temperature of the air adjacent to the outside of interior panel 28 balances out to the external temperature. If the internal temperature of the structure is maintained at 72 degrees Fahrenheit, the amount of heat transferred through interior panel 28 is Q=U×A×ΔT. U is the thermal conductivity of the interior panel, or the inverse of thermal resistance 1/R; A is the cross sectional area of the panel; and ΔT is the temperature differential between the external air and the inside wall of interior panel 28. In the summer, if the inside of the structure is to be maintained at 72 degrees, the ΔT can reach (120−72)=48 degrees or in the winter ΔT can reach (−30+72)=102 degrees. This compares to Air Barrier System 10 in which the temperature of the flowing air 42 is held at 55 degrees Fahrenheit keeping the outside of interior panel 28 at approximately the same temperature vs. the internal structure temperature at 72 degrees where ΔT=(72−55)=17. It can be seen that keeping the air flowing at 55 degrees cuts the heat loss or transfer through interior panel 28 at the extremes by ratios of 17/48 and 17/102 or by approximately a 1/2 factor in summer and a 1/6 factor in winter.
Moving the constant temperature air 42 at an approximate rate of 2 to 3 cu. ft. per minute between exterior panel 24 and interior panel 28 also minimizes the conductive heat transfer across air gap 26 even further reducing the above ratios.
In order to minimize the work required by the heat exchanger 12 or 46 to move air 42 and compensate for slight variations in temperature of flowing air 42 and maintain a flow rate through the plurality of closures 18 connected to Air Barrier System 10, the plumbing schemes shown in
A plurality of structural opening closures 18 can be hooked to a closed loop system with insulated tubing 16 run from the constant temperature source to the top port 32 of each closure. After distal closure 18 the constant temperature air source is capped with top line plug 20. The proximal end of the constant temperature return is capped with bottom line plug 22 before proximal closure 18 and successive bottom ports 48 are connected with insulated tubing 16 to the constant temperature air return which flows through insulated tubing 16 back to the constant temperature source. This layout aids in balancing the flow through each gap 26. The proximal structural opening closure 18 has the highest input pressure and lowest return suction and the distal structural opening closure 18 has the lowest input pressure and the highest return suction tending to balance the flow through each gap 26. The top and bottom ports 32 and 48 have openings to gaps 26 between exterior panels 24 and interior panels 28.
Power to run the water pump or the fans to move subterranean air through conductive tubing 14 to the heat exchanger 12 and the fan to move the constant temperature air 42 through the heat exchanger 12 and through insulated tubing 16 to the various closures 18 and back to heat exchanger 12 can be provided from any of a variety of sources. Roof mounted solar collectors 52 with energy storage facilities 54 for night or grey days are an option although they represent maturing technologies and are not part of this invention.
The descriptions in the above specification are not intended to limit this invention to the application or the materials disclosed here. Rather, they are shown for illustration purposes only as one skilled in these arts could easily scale the invention's dimensions and materials to work with any size structural opening closure and conduit feeding constant temperature air through an air gap between panels that close a structural opening. The only limitations are as described in the attached claims.