Patent Publication Number: US-2010116264-A1

Title: Roof-covering element

Description:
TECHNICAL FIELD 
     The present invention relates to a roof-covering element, having an upper surface, a lower surface and an interlocking arrangement for interconnecting neighbouring elements, whereby a plurality of elements is juxtaposed in a particular way for roof covering. The present inventions relates in particular to such a roof-covering element which comprises means for heat exchange with the environment. 
     BACKGROUND ART 
     The roof, i.e. the top covering of a building, can essentially be found on each and every building in the world. On one hand, the purpose of a roof is to shed rain water off the building and to prevent it from accumulating on top of the building. On the other hand, roofs have a more and more important decorative function. To realise these objectives, roofs can be built with different forms and shapes and using many different materials. With respect to the form, roofs can be highly pitched (sloped) or low sloped in form. While pitched roofs are in general found on industrial or commercial type structures, low sloped roofs are the primary design found on residential homes. As roofs are fully faced toward the sky, they must resist to all weather conditions. In particular, they have to be watertight, secure, durable, attractive and elastic enough to withstand important temperature shifts without cracking. Subsequently, roof-building techniques and roofing materials have been refined continuously for centuries to bear roofs of considerable strength and durability. 
     Over the millennia, people have surfaced their homes with just about anything that would hold the weather out, from animal skins to tree bark. Today, there are many roofing options with respect to the material, colour, shapes etc. The use of different roofing materials depend largely on particular weather conditions, but also and aesthetic criteria. Traditional roof coverings—slate and wood shakes—have remained virtually unchanged for centuries. On the other hand, new materials such as asphalt/fibreglass composites, lightweight concrete and metal tiles are products of the technological revolution. Each of these materials has slightly different durability, appearance, cost and ease of application. Furthermore, contemporary roofs are complex systems, made up of a variety of components that work together. 
     In the last decades, the so called solar roofing systems have increasingly been used for roof covering. These systems are designed in such a way to be able to generate electricity and/or to produce hot water or hot air, in addition to act as a roof covering. Typically, these systems make use of the so called solar cells. A solar (or photovoltaic) cell is a piece of equipment that is capable of converting the solar energy into another kind of energy. An assembly of solar cells is generally referred to as a solar panel. Historically, solar cells and panels have been used in cases where electrical power from the grid were unavailable. Recently, solar cells have though been more and more used as a source of “clean” or alternative energy, in contrast to “dirty” power from nuclear power plants. 
     Solar systems can be built-in in roofs in many different ways. On the one hand, solar cells can be directly integrated in the covering of pitched roofs. These systems are usually referred to as solar shingles. Essentially, solar shingles are solar cells shaped like a conventional (slate or ceramic) shingle. 
     They are designed to fit nicely onto many different types roofs and to be compatible with regular shingles. Nevertheless, solar systems can also be mounted on an existing roof, e.g. solar panel on a tile roof, or integrated in a flat roof. 
     However, all known solar roofing systems present a number of huge disadvantages compared with regular roofs. To start with, all solar panels have a deep, dark, purplish-blue colour, such that roofs covered with the solar roofing systems look completely different than other roofs. Moreover, the installation of solar roofing systems is prohibited in different circumstances, i.e. in particularly old buildings or buildings of a particular historical relevance. Moreover, the majority of solar cells has an important dazzling effect, which can be a source for important inconvenience in the entire neighbourhood. An additional problem of conventional solar systems arise in connection with the integration of these solar systems in existing roofs. As solar roofing systems become increasingly popular, more and more house proprietors wants to replace existing roofs by solar roofs. Nevertheless, solar panels represent an additional weight for the underlying roof constructions, such that installing solar panels is often possible only after a thorough renovation of the whole roof structure. Similar problems arise with solar shingles, where the replacement of conventional shingles usually requires a new static calculations and an important modification of the roof support. 
     On the other hand, the so called geothermal exchange heat pumps or ground source heat pumps (GSHP) become also a more and more popular source of energy for heating buildings. These ground sorce heat pumps use the Earth as either a heat source, when operating in heating mode, or a heat sink when operating in cooling mode. Geothermal heat pumps have an external loop containing water or a water/antifreeze mixture, and a much smaller internal loop containing a refrigerant. Both loops pass through the heat exchanger. There are also the so called air source heat pumps (ASHP), which use the same principle but extract the heat from the air, rather than the ground. Thus, the installation of these pumps is simpler and cheaper. 
     However, these air source heat pumps present the drawback that, in the cooling mode, the evacuation of the superfluous heat is sometimes difficult. Some systems using air source heat pumps employ therefore additional cooling devices, such as ventilators, in order to draw off the heat. These ventilators are an additional ennoyance for the neigbours and contribute also to the high costs of these systems. 
     DISCLOSURE OF INVENTION 
     It is thus an objective of this invention to propose a new and improved roof-covering element that does not present the above-mentioned inconveniences and disadvantages of the prior art. 
     According to the present invention, these and other objectives are achieved in particular through the features of the independent claims. In addition, further advantageous embodiments follow from the dependent claims and the description. 
     In particular, this objective is achieved through the invention in that, in a roof-covering element, having an upper surface and a lower surface, whereby for roof covering a plurality of elements is juxtaposed in a particular way such that neighbouring elements are interconnected by means of an interlocking arrangement, and whereby the roof-covering element comprises means for exchanging heat with the environment, at least one of the surfaces of the element is at least partially made of a metal alloy. The advantage of such a device is, among other things, that the roof-covering element can be produced of a natural material. A metal alloy is a particularly suitable material for this purpose, as the kind of alloy and the mixing ratio of the different compounds can be chosen to satisfy all different requirements of the particular roof. In particular, an iron or aluminium alloy can be used in connexion with modern buildings, where the silvery shine of these materials can be particularly advantageous. In addition, a particular metal alloy to be used can be chosen in function of its thermal or mechanical characteristics for an optimal protection against atmospheric conditions and environmental influences. 
     In an embodiment variant, the metal alloy comprises any combination of copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe). This embodiment variant has the particular advantage, among other things, that the metal alloy comprising a combination of these components has a particularly advantageous proprieties with respect to the thermal, mechanical and chemical aspect. Thus, a roof-covering device made of this kind of metal alloy is particularly suitable for the realisation of the present invention. 
     In another embodiment variant, the metal alloy comprises the alloy CuZn 40 Mn 2 Fe 1 . The alloy CuZn 40 Mn 2 Fe 1  has the particular mechanical characteristics, that make it very suitable for the present invention. In particular, this alloy, known also under the trademark DORNA-A® has a particular surface colour that is not substantially different from the colour of the conventional tiles or other similar roof-covering elements. Thus, a roof-covering element according to this embodiment of the present invention has the advantage of being very easily interchangeable with the conventional roof-covering elements. 
     In another embodiment, a cavity is provided inside the element, between the upper surface and the lower surface of the element, whereby a fluid is circulable in the cavity for heat exchange with the environment. The advantage of this embodiment is, inter alia, that a fluid can be brought to circulation inside the roof-covering device for heat exchange with the environment. The roof-covering element offers a good platform for heat exchange between the fluid and the outside air, through natural convection. Moreover, the sun light can heat the fluid inside the cavity of the roof-covering element such that the heat exchange can work in both directions (i.e. cooling or heating of the fluid). In this way, the building with the roof made of roof-covering elements according to this embodiment of the present invention can be heated or cooled, depending on the needs. Moreover, this particular embodiment of the present invention allow a good collaboration with air source heat pump systems, where the superfluous heat can easily be dissipated in the environment. 
     In a further embodiment, at least one nipple with an opening is provided in at least one surface of the element, whereby the opening of the nipple is connected with the cavity. This embodiment has the advantage, among other thins, that the fluid can easily be filled in the cavity, or extracted from the cavity of the roof-covering element. The nipple has in addition the advantage that a tube or another similar device can be easily attached to it and thus to the roof-covering element, for circulating the fluid. 
     In a further embodiment, the cavity comprises a channelling system. 
     The advantage of this embodiment is, among other things, that the internal surface of the cavity of the roof-covering element can be increased, such that the heat exchange with the environment can be facilitated. Using an appropriate channelling system, the internal surface can be significantly increased, such that a much better heat exchange rate can be achieved in comparison with similar other devices without such a channelling system. 
     In another embodiment of the present invention, the upper surface and/or the lower surface of the element comprises a fin structure. The fin structure can in particular be formed similar to the structure of a radiator or a similar device. The advantage of this embodiment is, among other things, that the particular fin structure of the surface of the roof-covering element allows to render possible a very efficient heat exchange with the environment. As at least one of the surfaces of the roof-covering element in a preferred embodiment is at least partially made of a metal alloy, the heat exchange with the environment can be accelerated and expedited using the special fin structure with a larger surface. 
     In another embodiment, the fluid is water and/or an aqueous solution. Water is very suitable for heat exchange thanks to its advantageous thermal characteristic. In the same way, aqueous solutions, in particular solutions with an antifreeze matter help to achieve an even more important effect. 
     At this point, it should be stated that, besides the roof-covering element according to the particular embodiments of the invention, the present invention also relates to an assembly of roof covering elements, a heat exchange system in a building or similar structures, a method of manufacture of a roof-covering element and a method for roof covering using the roof-covering element according to the present invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present invention will be explained in more detail, by way of example, with reference to the drawings in which: 
         FIG. 1  is a perspective representation of a conventional roof-covering element; 
         FIG. 2  is a perspective representation of an assembly of conventional roof-covering elements of  FIG. 1 , which are juxtaposed in rows and columns and interconnected by means of an interlocking arrangement for covering one part of the roof; 
         FIGS. 3   a  and  3   b  are sectional representations of two embodiments of the roof-covering element according to the present invention; 
         FIG. 4  are perspective representations of an assembly of roof-covering elements according to the present invention with the corresponding tubing arrangement;  FIG. 4   a  shows the tubing arrangement being attached to the roof-covering elements;  FIG. 4   b  shows the tubing arrangement being separated from the roof-covering elements; 
         FIG. 5  is a view from below of an assembly of roof-covering elements according to the present invention with the corresponding tubing arrangement; 
         FIG. 6  are sectional representations of the assembly of roof-covering devices according to the present invention of  FIG. 5 ;  FIG. 6   a  is the sectional representation taken along the line B-B of  FIG. 5 ;  FIG. 6   b  is the sectional representation taken along the line A-A of  FIG. 5 . 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION 
       FIG. 1  illustrates a conventional roof-covering element  10 , generally referred to as a tile. In  FIG. 1 , the reference numeral  11  refers to an upper surface of the roof-covering element  10 . The upper surface of the roof-covering element  10  can have different forms and profiles, and can also present different patterns, colours or structures. The upper surface  11  of the roof-covering element  10  can in particular be treated by mechanical or chemical means in order to achieve a particular optical, mechanical or thermic effect. The upper surface  11  of the roof-covering element  10  can also have a particular glaze or similar coating. In addition, the roof-covering element  10  in  FIG. 1  possesses an interlocking arrangement  13 ,  14 ,  15 , which is used for interconnecting adjacent roof-covering elements  10  when they are used in roof covering. 
     This interlocking arrangement  13 ,  14 ,  15  is basically built-up of both horizontal and vertical beads  13 ,  14  and grooves  15  in the peripheries of the roof-covering element  10  which work together to interconnect safely neighbouring elements  10  into a continuous assembly. It is well understood that the interlocking arrangement  13 ,  14 ,  15  can comprise additional interlocking, fastening and/or binding means (such as clamps or nails) for a safe and stable interconnecting, fastening and binding of neighbouring elements  10  on the roof. 
     An assembly of conventional roof-covering elements  10  of  FIG. 1 , which are juxtaposed in rows and columns and interconnected by means of the interlocking arrangement  13 ,  14 ,  15  for covering one part of the roof is shown in  FIG. 2 . The reference numeral  20  in  FIG. 2  refers to framework bars which function as support for the roof-covering elements  10 . Typically, the framework bars  20  are made of wood. However, the framework bars  20  could also be made of any other suitable material. The roof-covering elements  10  are hung from the framework bars  20  in a number of parallel rows, whereby each row overlaps the row below it to exclude rainwater. As mentioned above, additional fastening means could be used in order to safely fasten the roof-covering elements  10  to the roof. The particular arrangement of the roof-covering elements  10  therefore also allows to hide the fastening means (i.e. nails or hooks) that sustain the row situated immediately below. As a matter of course, different other ways of covering roofs using the roof-covering elements  10  are imaginable, particularly with respect to the way in which the roof-covering elements  10  are arranged and/or interconnected. 
     Examples of the roof-covering element  10  according to different embodiments of the present invention are shown in  FIG. 3 :  FIG. 3   a  illustrates a sectional representation of the roof-covering element  10  according to a first embodiment of the present invention, and  FIG. 3   b  illustrates a sectional representation of the roof-covering element  10  according to a second embodiment of the present invention. In  FIG. 3   a , the reference numeral  11  refers again to an upper surface of the roof-covering element  10  and the reference numeral  12  to a lower surface of the roof-covering element  10 . As it can be seen in  FIG. 3   a , the upper surface  11  of the roof-covering element  10  can have a particular shape or profile, which can be chosen based on aesthetic, functional, architectural or any other criteria. Although the upper surface  11  of the roof-covering element  10  in  FIG. 3   a  has a concave profile, the profile or shape of the upper surface  11  of the roof-covering element  10  can have any other form, including a convex or flat profiles. The lower surface  12  of the roof-covering element  10  is basically flat, although other shapes of the lower surface  12  are possible. Nevertheless, as the lower surface of the roof-covering element  10  is basically not exposed to views, its shape can be chosen in any way, as soon as it does not limit the functionalities of the roof-covering element  10 . 
     The roof-covering element  10  of the first embodiment of the present invention in  FIG. 3   a  also comprises the interlocking arrangement  13 ,  14 ,  15 , consisting of beads  13 ,  14  and grooves  15 . The beads  13 ,  14  and grooves  15  of the interlocking arrangement  13 ,  14 ,  15  are designed in such a manner that they are able of easily interconnecting neighbouring roof-covering elements  10 . In particular, the bead  14  is designed to work together with the groove  15 , while the bead  13  is designed to work together with the groove on the lower face of the bead  14 . Moreover, the roof-covering element  10  comprises typically other beads and grooves extending in a direction perpendicular to the section plane in  FIG. 3   a . It is however obvious, that the roof-covering element  10  can be provided with other means allowing an easy and reliably interconnection of adjacent elements  10 . In this manner, any roof can be covered with continuous rows and columns or any other assembly consisting of individual roof-covering elements  10 . The roof-covering element  10  of the first embodiment of the present invention in  FIG. 3   a  comprises a recess  14   a  in the bead  14 . The recess  14   a  can in particular be used for deploying a fastening or binding means which can be used for a better hold between two roof-covering elements  10 . In this manner, the interconnection between two elements  10  can be strengthened in order to achieve a particularly secure and resistant roofs, even under very bad weather conditions. Of course, fastening or binding means for reinforcing this interconnection can also be placed at a different place on the roof-covering element  10 . On the other hand, the recess  14   a  can be used to adjust correspondingly the weight of the roof-covering element  10 , when necessary. 
     The upper surface  11  and the lower surface  12  of the roof-covering element  10 , as well as the interlocking arrangement  13 ,  14 ,  15  and other parts of the roof-covering element  10  can be made of a same material. One or various parts can however be made of a material which is different than the material of the other parts. In particular, at least the upper surface  11  of the roof-covering element  10  can at least partially be made of a metal alloy. This metal alloy can in particular comprise a combination of copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe). However, this metal alloy can also comprise any other combination of these or other metals. This metal alloy can also contain non-metal substances, which are particularly necessary or advantageous for achieving special properties of the alloy. At the same time, the other parts of the roof-covering element  10  can be made of another material, in particular of another metal or metal alloy, but also of non-metal materials such as clay, ceramic, glass, plastics or other synthetic materials. For example, the upper surface  11  of the roof-covering element  10  can be made of a first metal alloy, the lower surface  12  of the roof-covering element  10  of a second metal alloy, and the interlocking arrangement  13 ,  14 ,  15  of a third metal alloy. It can be appreciated that any other combination of materials is possible, without leaving the general inventive concept of the present invention. 
     The reference numeral  16  in  FIG. 3   a  refers to a cavity, formed inside the roof-covering element  10 , between the upper surface  11  and the lower surface  12 . The size, shape and dimensions of the cavity  16  can vary without changing the fundamental idea of the present invention. In particular, this cavity  16  can extend over the whole area of the roof-covering element  10 , but also comprise just a small area compared with the overall area of the roof-covering element  10 . The cavity  16  is formed in such a way that a fluid can circulate inside the cavity  16 . The fluid can in particular be water or a particular aqueous solution, but can basically be any other suitable fluid. The used fluid can in particular also be an water/antifreeze solution, which can be used in a very important temperature range without any difficulties caused by low temperatures. In particular suitable antifreezes are propylene glycol, denatured alcohol and/or methanol). As fluid is confined in the cavity  16  inside the roof-covering element  10  between the upper surface  11  and the lower surface  12 , the heat exchange between the fluid and the environment can easily be realised. In particular, the upper surface  11  of the roof-covering element  10  stands in an continuous contact with the outside air, such that the temperature difference between these two media can lead to the heating or cooling of the fluid inside the roof-covering element  10  without any additional action or mechanism. Moreover, metal alloys in general and particularly alloys containing copper have very advantageous thermal characteristics, such that the heat exchange with the environment can be realised in an optimal way. In addition, being exposed to the sun, the upper surface  11  of the roof-covering element  10  is particularly subject to a very important heating up, in the way that the fluid inside the cavity  16  of the roof-covering element  10  can easily achieve very high temperatures. 
     Furthermore, the roof-covering element  10  according to the first embodiment of the present invention in  FIG. 3   a  comprises a nipple  17 , which on it&#39;s own comprises an opening  17   a.  The nipple  17  in  FIG. 3   a  is formed in the lower surface  12  of the roof-covering element  10 . It is however evident that the nipple  17  can be formed in any other place on the roof-covering element  10 , including in particular the upper surface  11 , the interlocking arrangement  13 ,  14 ,  15 , or side surfaces of the roof-covering element  10 . Of course, the roof-covering element  10  can comprise more than one nipple  17 , if required. The opening  17   a  of the nipple  17  is connected with the cavity  16  in such a way that the fluid can enter and/or leave the cavity  16  through the opening  17   a  of the nipple  17 . The roof-covering element  10  can i.e. comprise a tap for closing the opening  17   a  of the nipple  17 , once the fluid has been filled in or evacuated from the cavity  16 . In this way, the cavity  16  of the roof-covering element  10  can be filled with the fluid for heat exchange with the environment and emptied after the fluid has reached the desired temperature. 
     A second embodiment of the roof-covering element  10  according to the present invention is illustrated in  FIG. 3   b . The second embodiment of the roof-covering element  10  according to the second embodiment of the present invention has a very similar structure as the roof-covering element  10  according to the first embodiment of the present invention. The same reference numerals are again used to refer to the same components: the reference numeral  11  refers to the upper surface and the reference numeral  12  to the lower surface of the roof-covering element  10 . The reference numerals  13 ,  14 ,  15  refer to the interlocking arrangement, and the reference numeral  16  to the cavity between the upper surface  11  and the lower surface  12  of the roof-covering element  10 . The reference numeral  17  refers to a first nipple with the opening  17   a  and the reference numeral  17 ′ to a second nipple which has basically the same structure and function as the first nipple  17 . The cavity  16  in this second embodiment of the present invention comprises a channelling system  18 . The channelling system  18  comprises various furrows and twists which increase significantly the inner surface of the cavity  16 . In such a way, the heat exchange between the fluid confined inside the cavity  16  and the environment can be particularly effective. As the walls of the channelling system  18  are directly connected with the upper surface  11  of the roof-covering element  10 , the heat exchange between the upper surface  11  and the fluid inside the cavity  16  can also be realised in a very effective and easy way. 
     As it can be very much appreciated from  FIG. 3   a  and  FIG. 3   b , the visual aspect of the roof-covering element  10  according to these two embodiments of the present invention do not differ whatsoever from the optical appearance of a conventional roof-covering element. Their shape, including the shape and function of the interlocking arrangement  13 ,  14 ,  15  of the roof-covering elements  10  are designed to reproduce in an exact manner the corresponding elements of a conventional roof-covering elements. Moreover, the use of a particular alloy (i.e. the copper alloy CuZn 40 Mn 2 Fe 1  with its particular properties) allows the roof-covering element  10  according to an embodiment of the present invention to have significantly the same colour as conventional clay-made roof-covering elements but without the need for any additional mechanical or chemical treatment of the surface. Moreover, the roof-covering element  10  of the present invention can preferably be designed in such a way to exhibit also exactly the same weight as a conventional roof-covering element having the same shape. This particular feature allows an easy exchange of existing roof-covering elements and their replacement with the roof-covering elements according to the present invention without need for any additional changes on the roofing structure or other roof elements. On the other hand, the roof-covering element  10  according to these embodiments of the present invention does present the particular advantage of heat exchange, without the above-mentioned disadvantages of the conventional solutions. 
       FIG. 4  shows an assembly of roof-covering elements  10  according to any one of the embodiments of the present invention on a portion of a roof with the corresponding tubing arrangement  25 .  FIG. 4   a  shows the assembly with the tubing arrangement  25  being attached to the roof-covering elements  10  and  FIG. 4   b  shows the same assembly with the tubing arrangement separated from the roof-covering elements  10  . As it can be seen, the individual tubes interconnect two elements  10 . It is evident for any person skilled in the art that the arrangement of tubes and the choice of interconnection patterns can be varied without departing from the general inventive concept. The tubes are attached to the nipples  17 ,  17 ′ of the corresponding roof-covering elements  10  and thus interconnect the cavities  16  of the elements  10 . In this particular manner, all individual roof-covering elements  10  build a linked system in which the fluid can freely circulate throughout the system. In this system, it is in particular possible to create a fluid flow in a direction, where the fluid enters the system at a first roof-covering element  10  and leaves the system after having visited all roof-covering elements  10  in the assembly. This flow can in particular be supported by means of a pump (not shown) or any other similar device. In this way, an optimal heat exchange can be realised. 
       FIG. 5  is a view from below of an assembly of roof-covering elements  10  according to the present invention with the corresponding tubing arrangement  25 .  FIG. 6  shows sectional representations of the assembly of roof-covering devices  10  according to the present invention, shown in  FIG. 5 .  FIG. 6   a  is the sectional representation taken along the line B-B of  FIG. 5 , while  FIG. 6   b  is the sectional representation taken along the line A-A of  FIG. 5 . These Figures show one of the possible structures of an assembly of roof-covering elements  10  according to any one of the embodiments of the present invention. The same reference numerals are again used to refer to the same components, the structure and function of which, for simplicity, will not be exposed again. 
     Although the present disclosure has been described with reference to particular means, materials and embodiments, one skilled in the art can easily ascertain from the foregoing description the essential characteristics of the present disclosure, while various changes and modifications may be made to adapt the various uses and characteristics without departing from the spirit and scope of the present invention as set forth in the following claims.