The present invention generally relates to the field of heating systems for habitable structures. In particular, the present invention is directed to a radiant heat barrier and method of using same.
Radiant heating systems, such as hydronic and electrical resistance type radiant floor and ceiling heating systems, are becoming increasingly popular for heating private homes and public spaces. This is so due to a number of factors, including declining costs and the increase in personal comfort as compared to other types of heating systems, e.g., forced hot air and baseboard type systems.
In many conventional radiant floor heating systems, one or more radiant heating elements, e.g., hydronic tubing or electrical resistance mats, are located beneath a finished floor of a heated space above. The radiant heating element is typically embedded either in a lightweight concrete (typically, hydronic) or mastic (typically, electrical resistance mat) layer located above the floor framing or, alternatively, located below the subflooring between adjacent floor joists (typically, hydronic or electric). In any of these cases, it is important that the heat energy radiated from the radiant heating element be provided as completely as practicable to the space intended to be heated by the heating system. In the case of a radiant floor heating system, this heated space is typically the space directly above the floor.
In some existing installations, heat from the heating element(s) is inhibited from reaching the space below the flooring system by providing various types of conventional insulation. One type of such insulation is a multilayer mat having thermally reflective outer layers and a thermally insulating core sandwiched between the outer layers. An example of such a multilayer mat is the currently available ASTRO-FOIL® insulation mat that consists of aluminum foil outer layers sandwiching two plastic bubble-cell layers. These mats are generally sold in roll form in widths wider than typical inter-joist clear spacing and are often installed within the joist bays between spaced adjacent floor joists. A typical installation involves: 1) centering the mat width-wise within the joist bay; 2) pushing the insulation upward but not into contact with the underside of the subflooring and radiant heating element, if present; 3) folding the over-width marginal portions along the joists downward; and 4) stapling these marginal portions to the joists to fasten the mat into place. This installation process is relatively labor-intensive, particularly in the folding and stapling of the marginal portions. The installation of a number of other types of heat barriers have their own installation shortcomings.
In one aspect, the present invention is directed to a radiant heating system for installation in a structure that includes a heated space and has at least one framing bay defined by a pair of adjacent framing members and having a first longitudinal axis. The radiant heating system comprises a radiant heating element configured to be located proximate to or within the at least one framing bay defined by the pair of adjacent framing members. The heating element is designed to provide heat to the heated space when installed. A radiant heat barrier is configured to be installed in the at least one framing bay. The radiant heat barrier comprises a substantially rigid member that includes, when installed in the at least one framing bay, a concave surface spaced from the heating element and facing the heating element and the heated space. The concave surface defines a concave region having a second longitudinal axis parallel to the first longitudinal axis of the at least one framing bay when installed therein.
A method of installing a radiant heat barrier in a radiant heating system of a structure having a heated space and that includes a framing bay having a longitudinal axis. The framing bay is located between a pair of adjacent framing members having a clear spacing therebetween, and the heating system includes a radiant heating element configured to be located proximate to or within the at least one framing bay. The heating element is designed to provide heat to the heated space. The method comprises providing a radiant heat barrier comprising a substantially rigid body having a concave surface that defines a concave region extending along the radiant heat barrier at least when the radiant heat barrier is installed. The radiant heat barrier is installed in the framing bay so that the concave surface faces the heated space and the radiant heating element.
A radiant heat barrier for installation in a structure including a heated space and a radiant heating system for heating the heated space. The structure includes at least one framing bay having a first longitudinal axis and being defined by a pair of adjacent framing members having a clear spacing therebetween. The radiant heating system comprising at least one radiant heat element for providing heat to the heated space. The radiant heat barrier comprises a member having a length and that is substantially flexurally stiff in a direction transverse to the length. The member has a configuration selected so that, at least when the member is installed in the at least one framing bay such that the length extends parallel to the first longitudinal axis of the framing bay, the member has a longitudinal concave surface extending along said length and facing the heating element and the heated space.
For the purpose of illustrating the invention, the drawings show a form of the invention that is presently preferred. However, it should be understood that the present invention is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein:
Referring now to the drawings,
Barrier 120 may provide its barrier effect by reflecting heat toward space 112 and/or by providing thermal resistance to convective and conductive heat. Consequently, each barrier panel 120A-C may include a reflective surface 120D (
Each barrier panel 120A-C is particularly designed to be installed in a framing bay 124, here, the space between adjacent floor joists 128A-B. In one embodiment, each barrier panel 120A-C is sized and constructed so that it retains a bowed shape and exerts a biasing force against the joists when properly installed. The biasing force may be large enough so that each panel 120A-C is self-supporting within joist bay 124 at least during installation due to the frictional forces between the joist-engaging edges 120E-F of the panel and the respective faces 132A-B of floor joists 128A-B. However, each barrier panel 120A-C need not be self-supporting. If not, or if downward slippage or movement is anticipated, e.g., due to the panel being subject to creep, or set, over time or, in the case of a pre-curved panel (see FIGS. 9A-B) having a relaxed overall width less than the clear spacing CS between floor joists 128A-B, one or more retainers, such as the stiff wire retainers 136 shown, may be provided to keep the panels in place or to provide a stop in the event that slippage or movement indeed occurs. Stiff wire retainers 136 may be insulation hangers conventionally used to retain batt-type insulation in joist bays. As those skilled in the art will appreciate, there are many other retainer types that may be used for retainer 136, such as wood blocking, metal stretchers, strapping, stapling, nailing, etc.
In order to retain its bowed shape and exert a biasing force, each barrier panel 120A-C may be designed to have an overall flexural stiffness between joist-engaging edges 120E-F sufficient for obtaining these goals, typically without requiring an inordinate amount of force by an installer to impart the bow into the panel for installation. The necessary stiffness may be provided to each panel 120A-C in a number of ways, including making the panel uniformly thick and selecting the material(s) and thickness to achieve the desired result or providing the panel with transverse stiffening ribs, among others. In other embodiments in which a biasing force is not utilized, e.g., if the biasing force is nominal or the relaxed overall width of each panel 120A-C is less than clear spacing CS between adjacent floor joists 128A-B, the stiffness and/or creep resistance of the panels need only be sufficient for the panels to retain their shape once installed. Several configurations and constructions suitable for barrier panels 120A-C and other barrier panels of the present invention are discussed below in connection with FIGS. 9A-B and 10A-B.
As mentioned above, each barrier panel 120A-C may be provided with reflective surface 120D. In such cases, reflective surface 120D should face heated space 112 and it is desirable, though not absolutely necessary, to install each barrier panel 120A-C so that it is concave upward as shown in
In a joist-to-joist bias-type installation, i.e., an installation in which a panel is sprung between joists 128A-B, installed bow offset IBO results from making the relaxed overall width, i.e., the overall width in a direction perpendicular to joist-engaging edges 120E-F in the absence of any bowing forces, of each barrier panel 120A-C greater than clear spacing CS between floor joists 128A-B. Thus, installation of each such barrier panel 120A-C requires a force sufficient enough to move joist-engaging edges 120E-F toward one another a distance sufficient to allow the panel to be properly installed in confining space of framing bay 124.
Referring particularly to
It is desirable to seal the space 144 between flooring 104 and radiant heat barrier panels 120A-C from space 116 as thoroughly as practicable. As shown in
Referring to
In one embodiment, wherein barrier panels 120A-C are flat sheets in their relaxed state, each end closure 172 may be made by cutting a piece widthwise from a panel, e.g., a 6-inch (15.24 cm) piece. Since the width of the cut piece is wider than clear spacing CS between floor joists 128A-B for the reasons discussed above, the cut piece may be scored and folded at its widthwise margins to create flanges 180 that define a U-shaped end closure 172. If reflective surface 120D is present, each end closure 172 should be installed with the reflective surface facing confining space 144 between flooring 104 and barrier panels 120A-C. If the fit is not tight enough for end closure 172 to be self-supporting, flanges 180 may be fastened to joists, e.g., by stapling. If end closures 172 are used, it may be convenient to install them prior to installing barrier panels 120A-C.
It should be apparent to those skilled in the art that radiant heat barrier panels of the present invention, e.g., barrier panels 120, 220, 320 of
Referring to
Like other embodiments of a radiant heat barrier of the present invention, barrier 504 may include a reflective surface 504A facing the heated space 520 above subflooring 508 for reflecting radiant heat from the radiant heating element 524 toward heated space 520. An important feature of barrier 504 is its curved shape, which provides an installed bow offset IBO′ and curved reflector for reflecting heat toward the heated space. As with barrier panels 120A-C, installed bow offset IBO′ may be virtually any value, such as a value in a range from one-half the clear spacing CS′″ between adjacent joists 528A-B to one-sixteenth this clear spacing. The installed effective width IEW of barrier 504, i.e., the width of the curved portion, may be any value suitable for a particular application. However, in general, barrier 504 will typically be more effective the closer it is to the clear spacing between joists 528A-B.
FIGS. 9A-B illustrate a radiant heat barrier panel 600 suitable for use in any one of radiant heating systems 100, 200, 300, 400, 500 of
For example, an actual sample of panel 600 made of a particular type of fiberboard experienced enough creep over about a six-week period that the self-supporting biasing force of the installed panel reduced to a level that the panel began to slip. In this case, wire retainers were provided to limit the ultimate amount of slippage. Generally, if a panel of the present invention can retain its self-supporting biasing force for more than the few minutes it typically takes to install the panel, any adjacent panels, and the retainers needed, this would be suitable for many installations. Virtually all practical installation situations would be satisfied if the panel retains its self-supporting basing force for at least a day. Of course, longer self-supporting biasing force retentions times can be even more desirable. Indeed, some materials may experience so little creep over very long periods of time that retainers are not needed at all over the life of the installation.
In one embodiment, backing member 604 is made of a high-density cellulose pressboard. The flexural strength of this material as measured under the American Society for Testing and Materials (ASTM) standard D-790 may range from 2,000 PSI to 20,000 PSI, the modulus of elasticity under ASTM D-790 may range from 2×103 PSI to 2×108 PSI and the density under ASTM D-3394 may range from 0.50 gm/cc to 1.5 gm/cc. Based on this material and depending on the application, the thickness of backing member 604 may range from about 0.020″ to about 0.315″. At thickness much greater than this, it can become difficult to flex panel 600 by hand even at the lower end of the flexural strength range so that these greater thicknesses would typically not be suitable for joist-to-joist bias-type installations or installations similar to the installation of
Reflective layer 608 may be made of any one or more heat reflective materials, such as a metal foil, or metalized plastic, among others. Reflective layer 608 may be coextensive with backing member 604. However, in alternative embodiments, reflective layer 608 may be smaller in facial area than the facial area of backing member 604. Reflective layer 608 may be attached to backing member 604 in any manner appropriate for the materials selected for the reflective layer and backing member, such as adhesive bonding, heat bonding, chemical bonding, mechanical fastening, welding, and brazing, among others. Those skilled in the art will readily understand which attachment method is most appropriate for a particular combination of materials.
For a joist-to-joist bias-type installation of barrier panel 600, as discussed above the relaxed overall width ROW of the panel between framing member engaging edges 600A-B woiuld be selected to be greater than the clear spacing between the adjacent framing member between which the barrier panel is designed to be installed. For example, if the clear spacing is 14.5 inches (36.8 cm) (which is typical for 16 inch (40.64 cm) on-center spacing and conventional “2-by” dimension lumber), width W may be, say, 15.75 inches (40.01 cm). Actually, width ROW may generally fall within a large range of values greater than the clear spacing, but, practically speaking, in order to keep the curvature of the bowed shape reasonable, a relaxed overall width ROW of at least the clear spacing between the framing members at issue plus about 1 inch (2.54 cm) or more is typically desirable to account for deviations in framing member placement and other deviations so that a barrier panel has a sufficient bow when installed in spaces having dimensions within anticipated tolerances. As mentioned above relative to barrier panel 120A-C of
FIGS. 10A-B illustrate an alternative barrier panel 700 of the present invention. Barrier panel 700 differs from barrier panel 600 in two primary respects. First, while barrier panel 700 of FIGS. 10A-B has a backing member 704 and reflective layer 708 in a manner similar to barrier panel 600 of FIGS. 9A-B, reflective layer 708 does not extend entirely to the longitudinal structural member engaging edges 700A-B of barrier panel 700, nor to the edges 700C-D at the ends of length L′. While it will typically be desirable to have the reflective layer, if present, cover the entire backing member when this type of two-layer construction is used for a barrier panel of the present invention, barrier panel 700 illustrates that this is not a necessity. The other primary difference between barrier panel 700 and barrier panel 600 is that barrier panel 700 is manufactured to have a bowed shape, or curvature, in its relaxed state. In other words, barrier panel is “pre-curved” during manufacturing.
Generally, pre-curved barrier panel may be configured for use in either a sprung-type installation, e.g., like barrier panels 220, 320 of
The width W of modular unit 804 will be less than the clear spacing CS′″ between adjacent framing members 824A-B to one extend or another. For example, a width W that provides a gap 828 between modular unit 804 and one or both framing members 824A-B wide enough for an expand-in-place foam to be injected into this gap would allow the units to be secured in place with the expand-in-place foam 832. If, however, gap 828 is too small for injecting foam or other product, modular unit 804 may be secured in place using other means, such as adhesive (not shown) on the flats 836A-B or insulation hangers, among other things. Some installations, such as ceiling installation may not need to be secured at all.
Reflective surface 812 may be provided by attaching a foil or other heat reflective material 840 to insulation 816. Reflective material 840 may be provided across entire width W of the upper surface of modular unit 804 or, alternatively, may be provided only in the concave region of the unit. Preferably, though not necessarily, the width Wc of the concave region, or trough 820, should be as great a possible, taking into consideration any need to provide flats 836A-B for installation needs and/or the need to inhibit damage to modular unit 804 during shipping and handling. For example, it is desirable that width Wc of the concave region, or trough 820, be at least twenty-five percent of clear spacing CS″″ and, more preferably, seventy-five percent or more of the clear spacing.
Although the invention has been described and illustrated with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without parting from the spirit and scope of the present invention.