SOLAR ENERGY COLLECTOR ROOFING FOR BUILDINGS AND PANEL INCORPORATING THE SAME

Abstract: The roofing is comprised of assembled fluid-tight, thermoconducting board elements (1) forming fluid-tight junctions, said elements incorporating a plurality of longitudinal hollow sections (3) which communicate at their extremities (3a, 3b) with distribution (6) and collecting (7) conduits, respectively, forming part of a heat conveyor fluid circuit (A). The board elements (1), longitudinal sections (3) and distributor (6) and collector (7) conduits are resistant and constitutive elements of said roofing and substitute the roof. Each assembly panel incorporates a board element (1), various longitudinal sections (3) with their extremities respectively connected to a tube acting as distributor and to a tube acting as collector forming a circuit for the heat conveyor fluid (A) specific to the panel, with an inlet in the distributor tube and an outlet in the collector tube.

Description: The present invention concerns a solar energy collector roofing for buildings, said roofing being structural and self-supporting and being apt to replace a conventional roofing at no excessive additional cost thereby besides functioning as a solar energy collector. The present invention does besides concern a panel integrating a solar energy collector roofing for buildings of the above-mentioned type. The applications for this invention are varied within the field of the heat-exchanging plants used in different types of buildings. In the domestic field are to be pointed out the obtention of sanitary hot water, the radiant-floor heating, the warm-air heating, the air-conditioning through the use of a heat pickup machine, and the swimming pool conditioning. In the farming sector the invention can be used, for example, for harvest kilns and stable heating, and in the industrial sector it can find application as a heat supply means for thermal processes of low heat intensity. The harnessing of the solar energy makes sense to the fullest extent of the expression as a complement to the conventional energy production means based on nonrenewable sources such as petroleum, coal or uranium, or to power plants seriously affecting the environment such as the hydropower plants and aeolic plants. Although there is at present a technology allowing to directly transform the solar energy into electric power, said technology is extremely expensive and is hence reserved for very specific applications. Nevertheless, the utilization of the heat provided by the solar energy can be realized at a sensibly lower cost within the reach of most economies. Although a great part of the energy consumed in the developed countries is in form of electrical energy, a significant portion of this latter is used to produce thermal energy. Therefore, the thermal utilization of the solar energy has a wide application field for example for hot water supply and heating purposes especially in the household sphere. It would be therefore desirable to have a solar energy collector system apt to be individually installed for each building and able to totally or in great part meet the hot water and heating demands of said building, at least during the highest insolation periods. A massive implantation of such an energy collection system individually provided to each building would represent on a general level a great saving of other energies obtained from nonrenewable sources. Nevertheless, an essential condition for such a massive implantation to take place is that the installation of the solar energy collector device as an integrating part of a building has very reduced additional costs as compared with the costs of the already implanted standard approaches, said additional costs being even possibly null when providing a firstly erected building with said device. BACKGROUND OF THE INVENTION Numerous solar energy collector devices are known which are provided to be preferentially installed on the roof of a building. Patent US-A-4,338,921 specifies a classical example of a device of this kind comprising solar energy collector panels apt to be placed, for example, on top of a roof, as can be seen when looking at Fig. 1 of said patent. The collector panels warm up a liquid being pumped around a closed circuit comprising a heat-exchanging coil arranged inside a water tank connected to the circuit distributing the hot water to the building. The warm water from said tank is ulteriorly passed through a conventional electric or gas heater in order to thus raise its temperature up to a desired level. The system specified by said US-A-4,338,921 incorporates the essential elements defining any elementary system for the heating up of a fluid through solar energy especially in domestic applications. Nevertheless, the panels it incorporates can certainly be superimposed onto a conventional roof but in no case are conceived to replace said roof, this always entailing a cost of a considerable magnitude to be added to the cost of the conventional building. On the other hand, in the case of said panels their surface exposed to the solar radiation is of relatively reduced dimensions relative to the surface of the roof on which they are installed. This forces to seek a highest heat collection efficiency per unit of area, said requirement bringing about a high cost per panel to be added to the increase of the general cost of the plant. Patent EP-A-0 073 843 specifies a system of plates provided with elements for the accumulation of solar energy and apt to be extended on top of a conventional roof. This is another example of a device whose cost is to be added to that of the conventional roofing, said device hence not being an alternative to this latter. Patent EP-A-0000543 specifies a roof or skin air-conditioning building element apt to be used to collect solar energy thereby occupying the totality of the surface of a building roof section. This device comprises at the highest part of the constructive element two ducts for a heat-exchange liquid, a number of forked tubes orthogonally extending from said ducts towards the lower part and thus covering the whole region of the surface to be air-conditioned. Each of the two ends of the forked tubes is respectively connected to one of said two ducts of the upper part of the building element thus forming a closed circuit. A number of plates are arranged on top of and underneath said tubes thus covering said roof section. Also specified is the grouping of several of said tubes and plates thus forming panels. Although this patent does already foresee in one of its modes of operation the utilization of the whole surface of the roof of a building for the collection of solar energy, it has not been foreseen that the very elements forming the energy collecting system constitute structural members of the building provided to replace the conventional roof of this latter. In all of the embodiments of the above-mentioned patent said tubes, ducts and plates are not in fact bearing components of said building element but are rather provided to rest on top of an independent supporting structure provided with its own bearing members (as shown by Figs. 1, 8, 11 and 14 of said patent), although some of said embodiments provide that the elements of the device can possibly function as reinforcements for said supporting structure. Patent EP-B1-0 270 910 in its turn specifies a solar roofing provided to replace the roof of a building, said roofing being self-supporting and not requiring to be supported through a placement of girders. Said roofing is nevertheless in no way a conventional roofing since it has on its upper surface a number of reflecting and collecting surfaces forming a complex arrangement of compartments and folds in order to optimize the collection of the solar energy. At the bottom of said compartments channels of reduced passage cross-section are placed through which a heat carrying fluid (liquid or gas) circulates. The orientation of said reflecting and collecting surfaces must be accurately calculated, designed and realized according to the specific location and orientation of each building in particular. Due to its special configuration the roofing of said patent EP-B1-0 270 910 does not have an upper surface regular or strong enough to stand the weight of a person standing on it for example in order to check up or repair said roofing. On the other hand, due to the existence of compartments and folds on the upper surface of said roofing this latter becomes very prone to the formation of dust and earth deposits that can be consolidated by the growth of plants thus increasing the weight resting on its structural members and plugging the passages provided for the drainage of the rain water. Said compartments are also very inconvenient in case of wind or snow. Said roofing besides has an external appearance very different from that of the conventional roofings, this forcing to make an additional design effort in order to achieve the architectural harmonizing and integration of said roofing with the rest of the building. Finally the complexity of the structure and configuration of the part of said roofing exposed to the sun and the special conditions for its erection cause its cost to be sensibly higher than that of a conventional roofing made of metal, for example, and therefore its manufacture and installation will hardly attain the levels of massive implantation within the building industry required to reach the objectives of a collective energy saving and reduction of the environmental pollution sought by the present invention, the application of said roofing system being hence left as the private option of a house owner at the expense of a cost increase. FR 2330974 patent describes a solar energy capture device that may form a roof component, which consists of a receiver plate and at least one circulation pipe for the heat-carrying fluid, the said receiver plate and the said circulation pipe are integral parts of a single profile, which guarantees optimum heat transfer between the receiver plate and the circulation pipe, and the fact that the profiles are manufactured on a continuous production line means minimum component costs. In an example of the cited capture device, the said circulation pipe, at least, is located between two plates, where one is called the receiver plate and the other the structure plate, which results in a rigid capture device, which may then be self-supporting. Additionally, the cited profile contains side panels that simultaneously form elements for longitudinal rigidity, capture device supports and the means leak-tight coupling one capture device to the next. However the capture device in the cited FR2330974 patent is only a roof component, which does not resolve the complexity of a complete roof, and in addition it is only self-supporting when structural reinforcement components are added to the receiver plate and the circulation piping, such as the cited structure plate or the cited side panels, which do no perform any function within the solar energy capture and exploitation system. Additionally, the collector and distribution piping which is necessary for the said energy capture and exploitation system do not form an integral part of the capture device, so that they do not contribute any function of roof-strengthening elements. US-A-4 336 793 discloses a strip for forming a solar energy panel having a configuration that interlocks with heat transfer conduits wherein adjacent strips can be interlocked together to form panels, which can serve additionally as a roofing material. However US-A-4 336 793 does not disclose fluid-carrying tubes directly exposed to sunlight and are not integral to the strip (sheet metal) and thus not contributing to structural strengthening of the panel. It is therefore an object of the present invention to provide a roofing for buildings which besides functioning as a usual waterproofing, heat-insulating structural member of the construction at the same time is a solar energy collector, with production and installation costs equivalent to or only slightly higher than the costs of the conventional roofings, and with production and installation methods comparable to those used at present for said conventional roofings, in order to thus allow its massive implantation within the building industry both for firstly erected buildings and for the refurbishment of old buildings. Another object of the invention is to provide for a building a roofing provided to be able to collect solar energy without needing a specific orientation of each of its members, said roofing only requiring to be positioned as per a best suited general orientation of its totality and basing its efficacy on an exposure of the possibly biggest solar energy collecting surface rather than on the intrinsic efficiency of each of the collecting members. Yet another object of the invention is to provide for a building a roofing provided to be able to collect solar energy and to be practicable, i.e. to allow and support the access of a person to its surface for inspection or repair purposes, for example. An additional object of the invention is to provide for a building a roofing provided to be able to collect solar energy thereby having a clear upper surface with no hindrances to obstruct the drainage of water. A further object of the invention is to provide for a building a roofing provided to be able to collect solar energy and having an external appearance similar to that of a conventional metallic roofing and hence not requiring for its application to be additionally harmonized with the usual building elements since it exhibits once installed a full architectural integration. One last object of the invention is to provide for a building a roofing system provided to be able to collect solar energy and to be apt to be formed by means of connecting several previously checked prefabricated panels. SUMMARY OF THE INVENTION These objects are attained by providing a solar energy collector roofing for buildings which is formed by a system of plate members made of a heat-conductive, waterproof material and apt to be connected to each other thus forming also waterproof connections, said plate members incorporating channels for a heat carrying fluid connected at their ends to a distributor duct and to a collector duct, respectively, thus forming a part of a generally closed circuit provided for the thermal utilization of the energy accumulated by said fluid, in such a way that the whole surface area of the roofing becomes a single solar-heat collector. Preferably said plate member, including said channels, has its lower surface lined with a thick layer of heat-insulating material functioning both to prevent the heat carrying fluid from loosing heat through the tubular shapes and to heat-insulate the building in a conventional manner. If desired, said heat-insulating material can have its open surface covered with a finishing plate or sheet. An essential characteristic of the instant invention lies in the fact that said plate members together with said channels and said distributor and collector ducts in their turn form structural members apt to be self-supporting and to totally or in great part possess the bearing capacities demanded from a conventional roofing, which, together with its heat-insulating and waterproofing properties, renders the solar energy collector roofing as per the present invention apt to replace a conventional roofing at low or null additional cost. In the roofing as per the invention the heat utilization circuit can be both an open or a closed circuit. In the case of an open circuit a generally gaseous fluid, especially atmospheric air, is introduced at a temperature T 1 through the distributor duct towards said plurality of channels where it gradually warms up by virtue of the solar radiation as it circulates till exiting at a temperature T 2 higher than T 1 through the collector duct directly into the premises or enclosure to be heated. Such an open circuit system is specially useful in applications such as farming kilns, stable heating, industrial bays, sports pavilions and the like. In case of the circuit being a closed one as in the majority of applications, especially those for providing sanitary hot water and domestic heating, a primary circuit is established which is the actual closed circuit, and a secondary circuit is also established which is open in the case of hot water for consumption or closed in the case of radiator heating, for example. The primary circuit is formed by the ducts of the roofing's heat collection system, i.e. the distributor duct, the plurality of longitudinal channels and the collector duct, and by a line section connecting the collector's outlet with the distributor's inlet after having passed through a heat-exchange section. Along said primary circuit circulates a heat carrying fluid (preferably common water) entering through the distributor duct at a temperature T 1 towards said plurality of channels where it gradually warms up by virtue of the solar radiation as it circulates through them till exiting at a temperature T 2 higher than T 1 through the collector duct from where it is conducted to said heat-exchange section (typically being a tank) which it enters from its top at the temperature T 2 to later on exit through the bottom at the temperature T 1 to be conducted from here again to the distributor duct. The secondary circuit is for example the circuit distributing the hot water to the building, and incorporates a heat exchanger, such as a coil, in said heat-exchange section, i.e. that said heat exchanger is submerged in said heat carrying fluid of the inside of said tank. The fluid of the secondary circuit enters the heat exchanger through its bottom at a temperature T 1 ' and exits through the top at a temperature T 2 ' higher than T 1 ' towards the place of consumption. The circulation of the heat carrying fluid in the primary closed circuit is normally produced by the convection of the very heat carrying fluid A (thermosyphonic circulation), although it can be assisted by a pump if that is deemed necessary. Such pump can be driven by an alternating-current electric motor fed from the mains supplying the building, or it can be driven by a direct-current electric motor fed from a photovoltaic module station collecting the solar radiation energy. It is evident that a collector made up as per the present invention, without a glass cover such as that usually equipping the conventional collectors, will have greater energy losses although its efficiency won't be much lower than that of said conventional collectors provided that it works at moderate fluid temperatures of up to 45°C. This not very favourable factor is compensated by the fact that the collecting surface available is much bigger as provided by the optimum use of the totality of the available surface area of the roofing of the building, and by the substantial weight and cost reduction brought about by the absence of said glass cover. In order to optimize the manufacture, installation and checking of the roofing, according a to a preferred exemplary embodiment of the present invention connectable panels have ben provided. Each panel comprises one of said plate members provided with a solar energy collecting surface and integrating a plurality of said longitudinal channels and tubes functioning as a distributor duct and a collector duct and arranged at the ends of the plate member as per a transversal arrangement with respect to the channels, the respective ends of said channels being connected to said tubes. Thus each panel integrates a subcircuit for a heat carrying fluid, with an inlet into the tube functioning as a distributor and an outlet out of the tube functioning as a collector. Each panel can also advantageously incorporate a layer of heat-insulating material lining the surface that is not exposed to the solar radiation, as well as a heat-insulating lining for the tubes functioning as the distributor and collector ducts. When in a building said panels are provided to have their lower part visible the open surface of the layer of heat-insulating material is lined with a finishing plate or sheet. The panels do also include at their sides means to facilitate their mutual connection in order to form roofings of great surface, in which case each of the individual subcircuits of each panel can communicate with the others so as to thus form part of a single circuit, either open or closed, for a heat carrying fluid, or else said subcircuits can communicate by groups thus forming several circuits. Said panels are preferably prefabricated, in which case they exit the works in a finished and checked condition thus guaranteeing that they have passed adequate strength and pressure buildup tests. The installation of the roofing is thus limited to the placement and mechanical securing of the panels with their respective sides arranged in a mutually connected arrangement on adequate supports, to the waterproofing of the connections between the panels (if said waterproofing is not automatically established by the very shape of the plates), to the connection of the inlets and outlets of the individual subcircuits of each panel thus forming one or more open or closed circuits as per a predesigned diagram, and to the final finishing of the roofing with gutter, ridge cap, finial and leader members and the like, whereupon the whole plant can be advantageously put on site through a final pressure buildup test under load. A typical application of the roofing as per the present invention is that of providing sanitary or heating hot water in the domestic sphere. In such a case the system comprises one or more primary circuits for a heat carrying fluid, i.e. those closed circuits comprising the channels and the distributor and collector ducts of the roofing, and one or more secondary circuits, i.e. those circuits distributing the water to the dwelling or dwellings of the building. The heat transfer between the primary circuit or circuits and the secondary circuit or circuits is carried out in one or more heat-exchange sections for example of the tank-and-coil type, with the particularity that the heat carrying fluid of the primary circuit is the fluid filling up the tank, and the fluid of the secondary circuit is the fluid circulating through the coil submerged in the tank. The fluid used as a heat carrier in the primary circuit is selected from the group formed by tap water, deionized water treated with corrosion inhibitors and/or antifreeze, heat-transfer oil or any other fluid apt to be used for the specific application in question. The nature of said fluid will determine the dimensions and materials characteristic of the structural tubular shapes and the conditions for their maintenance. In an exemplary embodiment of the invention one or more tanks for one or several heat-exchange coils besides form supporting members for the collector duct or ducts thus additionally functioning as structural members supporting the roofing. The essential advantages offered by the solar energy collector roofing for buildings being the object of the present invention are the following: it is a self-supporting solar energy collector roofing wherein each member functions as a conventional bearing, waterproofing and/or heat-insulating member, and at the same time functions as a solar thermal energy collecting, preserving and/or conducting member, the manufacture and installation of said roofing hence not necessarily involving a cost increase relative to a conventional roofing of equivalent quality; it has an accessible and clear outer surface with no hindrances to obstruct the drainage of the rain water or the snow, said surface besides functioning as a bearing member; its external appearance does not substantially differ from those of the conventional metallic roofings; its production and installation does not require techniques different from those used for the conventional roofings, said solar energy collector roofing hence being apt to be directly integrated with the usual procedures of the building industry. A massive implantation in the short term of the solar energy collector roofing for buildings as per the present invention is made possible by all these advantages, with the consequent contribution to the energetic saving and to the lowering of the environmental pollution levels it entails. BRIEF DESCRIPTION OF THE DRAWINGS A more detailed description of the invention is given below by means of exemplary embodiments shown in the accompanying drawings provided only by way of illustrative examples in no case limiting the scope of the present invention. In the drawings: Fig. 1 is a plan-view of a roofing as per the invention; Fig. 2 is a plan-view of a roofing formed from several panels as per the invention; Fig. 3 is a perspective view of a panel integrating the roofing of Fig. 2; Figs. 4 through 10 are enlarged views showing different ways to integrate channels with a plate member either of the roofing or of the panel of the invention; Figs. 11 through 14 are enlarged front views showing different alternative arrangements of the connection between two adjoining plate members of the roofing or of the panels of the invention; Fig. 15 is a local elevation of a cross-section of a building provided with a roofing as per the present invention showing a functional sketch of this latter; and Fig. 16 is a top view of a tank integrating a roofing as per the present invention. DETAILED DESCRIPTION OF SOME EXEMPLARY EMBODIMENTS Referring in the first place to Fig. 1, a plan-view of a solar energy collector roofing as per the present invention is shown schematically by said figure. Said roofing is formed from several heat-conductive, waterproof plate members 1 apt to be connected to each other thereby forming waterproof connections in such a way that a solar radiation pickup surface is obtained which encompasses the whole surface of said roofing. Each of the plate members 1 integrates a plurality of channels for a heat carrying fluid A, said channels being formed by hollow, longitudinal shapes 3 attached to or integrating said plate member 1. Together with said longitudinal shapes 3 the plate member 1 forms an assembly that is apt to totally or in great part stand the stressing created by the design load of said roofing and corresponding to the roofing surface area formed by said assembly. Each of said longitudinal shapes 3 communicates through a first end 3a with a distributor duct 6 and through a second end 3b with a collector duct 7 thus forming a circuit for said heat carrying fluid A, said circuit generally being a closed circuit, as will be seen later on, with an inlet 6a into said distributor duct 6 and an outlet 7a out of said collector duct 7. The circulation of the heat carrying fluid A through said circuit is indicated by arrows in Fig. 1. The distributor duct 6 and the collector duct 7 are also designed in such a way that they are structural bearing members serving as rests for the plate members 1 forming the collector surface with the integrated longitudinal shapes 3, said ducts possibly resting at their ends on struts 80 or loadbearing walls. A layer 5 of a heat-insulating material is preferably applied as a lining to the surface not exposed to the solar radiation of said roofing, and if said layer is supposed to be visible it can be finished with a finishing plate or sheet 18 as is shown in Figs. 11 through 14. Plate members 1 fulfil the functions of waterproofing the building and collecting the solar energy. The material used to make them is selected from the group comprising stainless steel, zinc-plated or lacquered steel, copper, aluminium or any other nonmetallic material having the characteristic of being heat-conductive, of those usually employed in roofing. The outside surface is of dark colour, preferably black, in order to thus improve the sunbeam energy pickup. Longitudinal shapes 3 as well as distributor and collector ducts 6 and 7 fulfil a double function: on the one hand they constitute totally or partially self-supporting, rigidizing structural members of the roofing, and on the other hand they form ductings for the heat carrying fluid A. The material of the longitudinal shapes 3 and distributor and collector ducts 6 and 7 can be any of the already mentioned stainless steel, zinc-plated or lacquered steel, copper, aluminium or any other nonmetallic material having the characteristic of being heat-conductive. It is nevertheless important that if different materials are selected for said ducts and for the roofing plate the paired materials selected do not create high galvanic couples, since these latter are the cause of serious corrosion problems. The function of the layer 5 of heat-insulating material is to heat-insulate the collector plate members and the longitudinal sections 3 fitted to them thus preventing the collector system from loosing heat energy, said layer 5 also functioning to thermally and acoustically insulate the building as is otherwise usual. The material of the heat-insulating layer 5 is selected from the group consisting of glass wool mat, rock wool, polyurethane foam or any other material of similar characteristics of those usually employed in the building industry. The fluid A used as heat carrier is selected from the group formed by tap water, deionized water or water treated with corrosion inhibitors and/or antifreeze, heat-transfer oil, air or any other fluid being appropriate for the specific application contemplated. The nature of said fluid A will determine the dimensions and materials characteristic of the longitudinal sections 3, distributor and collector ducts 6 and 7 and further lines of the system, and the conditions for their maintenance. In order to optimize the manufacture, checking and erection said roofing is formed by one or more connectable panels as per the present invention. The roofing obtained with said panels is basically operated as per the same principles and is made of the same materials as set forth with respect to the roofing of Fig. 1. In Fig. 2 is shown schematically a plan-view of a solar energy collector roofing formed from several of said panels as per the present invention, and Fig. 3 shows in a perspective view one of said panels. Each of said panels compbises a heat-conductive, waterproof plate member 1 forming said solar radiation pickup surface. Hollow, longitudinal shapes 3 forming channels for a heat carrying fluid A are attached to or integral with said plate member 1, each of said longitudinal shapes 3 comprising a first end 3a and a second end 3b. At opposite ends of the plate member 1 and arranged as per a transversal arrangement with respect to the longitudinal shapes 3 are attached a tube 60 functioning as a distributor duct and a tube 70 functioning as a collector duct, said first ends 3a and said second ends 3b of the longitudinal shapes 3 being connect to and communicating with said tubes 60 and 70, respectively, thus forming for said heat carrying fluid A a subcircuit specifically pertaining to said panel, with an inlet 61 into said tube 60 and an outlet 71 out of said tub 70, said specific subcircuit being apt to form part of a general circuit that can be either open or closed. The panel has been designed in such a way that each plate member 1 together with said longitudinal shapes 3 and tubes 60, 70 forms a rigid assembly that is apt to totally or in great part stand the stressing created by the design load of said roofing corresponding to the roofing surface area covered by said panel. To illustrate this fact Fig. 2 shows several panels arranged as per a mutually adjacent arrangement and resting at the ends of the tubes 60, 70 on struts 80. In this example each strut supports the ends of two adjacent panels. As in Fig. 1, the flow of the heat carrying fluid A through the specific circuit pertaining to each panel is indicated by arrows. It is evident that all of the inlets 61 can come from different branchings of a single inlet duct (not shown), just as all of the outlets 71 can assemble into a single outlet duct (not shown), or both the inlets 61 and the outlets 71 can join in groups to connect with the rest of an open or closed circuit, or each inlet 61 and each outlet 71 can connect with an individual open or closed circuit. If this is deemed convenient, the panel as per the instant invention does besides comprise a layer 5 of heat-insulating material such as a foamed polymer or copolymer, fibreglass or the like lining that surface of the plate member 1 which is not exposed to the solar radiation, and especially if said layer 5 is to be visible said panel does also comprise as finishing plate or sheet 18 lining the open surface of said layer 5 of heat-insulating material (Figs. 10 through 13). The panel does also preferably comprise for said tubes 60, 70 a lining of heat-insulating material (not shown) such as a foamed polymer or copolymer, fibreglass or the like in order to reduce the heat losses from said tubes. The panel of the present invention is designed for mass production and can be carried out as per different embodiments as will be explained later on. It is important to point out that all those connections which have to form tight enclosures for the subcircuit conducting the heat carrying fluid and specifically pertaining to the panel, i.e. the connections to form or integrate the longitudinal shapes 3 with the plate member 1 and the connections of the first and second ends 3a and 3b of the longitudinal shapes 3 to the tubes 60, 70 are tight connections carried out by welding, by means of an adhesive or through the use of other similar procedures such as form fit bead-jointing or through a combination of several of said procedures, said connections being checked as for their strength and tightness hence meeting the reliability requirements demanded by the insurance companies thus offering a given guarantee to the buyer. In some exemplary embodiments in which the longitudinal shapes 3 are tubular members 40 (see Fig. 6) the attachment between said tubular members 40 and the plate member 1 is carried out by totally or partially inserting the former in a pressed-in fit into channels 30 formed in the plate member 1, without ulterior welding or use of adhesive. In another exemplary embodiment, not shown, the tubular members are simply applied onto the plate member, and the assembly is ulteriorly lined with the corresponding layer of heat-insulating material, this heat-insulating layer being for example sprayed on thus assuring the attachment between said members. Although the plate members and the panels can be tailor made for a specific construction, in order to lower the costs they are preferably mass produced with several standard dimensions the most common of them being of approximately 1.5 x 3 mtrs., although they can go up to approx. 2 x 6 mtrs. Nevertheless, in some exemplary embodiments much bigger lengths can be obtained, the panels being rolled from a sheet coil. These cases will nevertheless probably require intermediary bearing struts to support the installed facility. Figs. 4 through 10 show several alternative examples for the integration or attachment of the longitudinal shapes 3 with or to the plate member 1 to form part of a panel or directly of a roofing. It is to be pointed out that in the figures illustrating the present specification the thicknesses of the plates, the connections, the gaps and other similar aspects have been exaggerated in order to provide for a better understanding of the drawing. In the examples of Figs. 4 and 5 said longitudinal shapes 3 are formed, at least in part, from the very material of the plate member 1 by means of a forming operation carried out upon said plate member 1 at several spaced regions to thus determine longitudinal channels 30 delimited by lateral edges 31, said channels 30 being thereupon closed through joining said lateral edges 31. Whereas now in the example of Fig. 4 said closure of the channels 30 is carried out by joining the directly adjoining lateral edges 31, in the example of Fig. 5 said joining of the spaced lateral edges 31 is carried out by means of an added member 32 joining them. In the example of Fig. 6 plate member 1 has also been formed with channels 30 delimited by edges 31, but instead of being closed said channels are provided to totally or partially house tubular members 40 in their inside. The opening delimited by said edges 31 is advantageously narrower than the bottom of channel 30, a clamping effect thus taking place which retains the pressed-in tubular member 40 without requiring an ulterior fixation. Channels 30 can be of very small depth just enough to mark the location of the tubular members 40, or they can even disappear, in which cases there would be sprayed on the above mentioned layer 5 of heat-insulating material giving cohesiveness to the panel. In the example of Fig. 7 said hollow, longitudinal shapes 3 are formed by said tubular members 40 directly attached to any of the surfaces of said heat-conductive plate member 1 by means of spotwelds or weld beads or adhesive spots or beads. In the example of Fig. 8 said hollow, longitudinal shapes 3 are formed by members 50 of heat-conductive material and "U" cross-section attached to said heat-conductive plate of plate member 1 at the edges 51 of the ends of its legs. In the previous examples of Figs. 4, 5, 7 and 8 the attachments can be carried out by means of an adequate technique guaranteeing the structural attachment and when needed the tightness of the member, such as by welding or by means of an adhesive. In their turn in the examples of Figs. 9 and 10 the hollow, longitudinal shapes 3 are formed by tubular members 90, 95 having a given configuration of their cross-section which is apt to be form-fitted to guides formed with plate member 1 or attached to it. In the example of Fig. 9 tubular member 90 has at its bottom flanges 91 fitting into guides formed by guide members 92 attached to plate member 1. In the example of Fig. 10 tubular member 95 has a triangular cross-section arranged with its base resting on plate member 1 and having its vertices 93 adjacent to the base grasped by guide members 97 attached to plate member 1. In these two last examples guide members 92, 97 can be sections covering the whole extension of tubular members 90, 95, or they can be discrete, possibly very short, aligned and sensibly spaced sections defining said guides. When as in the examples of Figs. 9 and 10 said guides are not obtained through a forming of plate member 1, the attachment of guide members 92, 97 to plate member 1 can be carried out by means of any adequate technique, such as by welding or by means of adhesive. One particularity of the examples of Figs. 6, 9 and 10 lies in the fact that the tubular members 90, 95 can preferably forcibly slide along the guides formed by the respective guide members 91, 96, and therefore are easily assemblable and disassemblable. In another order of things, both in the roofing of Fig. 1 and in the panels of Figs. 2 and 3 the plate members 1 besides comprise arrangements provided at their longitudinal edges to facilitate the connection with other adjacent plate members 1 thus establishing waterproof connections. Said arrangements generally adopt an adequate shape apt to allow a proper fit. Figs. 11 through 14 show several alternative examples of how the plate members 1 are laterally fitted to each other both if they do as well as if they do not integrate a panel. In the example of Fig. 11 said mutual connection of said plate members 1 is carried out by way of an overlap connection wherein a first flange 1a adjacent to a lateral edge of one of said plate members 1 overlaps a second flange 1b adjacent to an adjoining lateral edge of another of said plate members 1 arranged as per a contiguous arrangement with respect to the first mentioned one. In the example of Fig. 12 said connection is carried out by way of an overlap connection wherein a member 24 overlaps a first flange 1a adjacent to a lateral edge of one of said plate members 1 and a second flange 1b adjacent to an adjoining lateral edge of another of said plate members 1 arranged as per a contiguous arrangement with respect to the first mentioned one, said overlapping member thus covering the gap between both contiguous plate members 1. In the example of Fig. 13 said connection is carried out by way of an overlap connection wherein a first flange 1c adjacent to a lateral edge of one of said plate members 1 overlaps a longitudinal shape 3 adjacent to an adjoining lateral edge of another of said plate members 1 arranged as per a contiguous arrangement with respect to the first mentioned one. Lastly in the example of Fig. 14 said connection is carried out by way of an overlap connection wherein a member 25 overlaps two longitudinal shapes 3 each belonging to each of the adjoining plate members 1 to be connected and being adjacent to the lateral edges of these latter, in such a way that said member 25 covers the gap between both contiguous plate members 1. As is obvious, when the plate members 1 of the examples of Figs. 11 and 13 incorporate said layer 5 of insulating material, as in the illustrated case, said respective flanges 1a and 1c are free of said layer 5 of insulating material. Referring now to Fig. 15 here is shown schematically in a local cross-section a saddle roof carried out as per the present invention. Each of the slopes is formed by a plurality of heat-conductive, waterproof plate members 1 with the corresponding longitudinal shapes 3 with ends 3a and 3b respectively connected to a distributor duct 6 and a collector duct 7 arranged as per a transversal arrangement. The distributor duct 6 is situated at the end placed at a lower level of the slope, whereas the collector duct 7 is situated at the end placed at a higher level. In the illustrated exemplary embodiment the connections between the longitudinal shapes 3 and the distributor and collector ducts 6 and 7 are carried out as plug-in connections wherein rigid couplings 17 integral with one of the parts are pressed into corresponding orifices equipped with a seal and provided in the other part. Said connections can also be carried out by means of elastic couplings fixed at their ends to corresponding nipples integral with each of the parts. If said panels are prefabricated panels said connections are permanent and are carried out through welding, use of adhesive, etc., and they are duly checked before commercializing said panels. A preferably heat-insulated tank 8 situated at a central location of the roofing, i.e. between the two slopes and at a level lower than, equal to or higher than that of the collector duct 7 forms a heat-exchange section whose function will be explained later on. In the illustrated example said tank 8 besides fulfils a structural function since it serves as a bearing strut for the collector duct 7. The system comprises for each slope a primary circuit for a heat carrying fluid A, formed by the longitudinal shapes 3 and the distributor and collector ducts 6 and 7 of the roofing, and a secondary circuit distributing the hot water to the house. The heat transfer between the primary circuit and the secondary circuit takes place in said heat-exchange section, i.e. in the inside of tank 8. In a same roofing there can evidently be more than one of said heat-exchange sections, including more than one tank 8. Said tank is generally not pressurized, i.e. it communicates with the atmosphere and therefore is at atmospheric pressure, for which reason the heat carrying fluid A filling said tank is subject to small evaporation losses. To compensate said losses an automatic system (not shown) has been provided to refill the tank with fluid A as per a preselected filling level, such as by means of a float-actuated valve system, in order to keep said level constant. Tank 8 is permanently filled with heat carrying fluid A circulating through the primary circuit. In effect, said heat carrying fluid A, warmed up by the insolation impinging upon plate members 1 and longitudinal shapes 3 of the roofing, passes once warm from collector duct 7 to the inside of tank 8 through the top of said tank to later on leave this latter, once cooled by the heat pickup effected by the heat-exchange water of the secondary circuit, through the bottom of said tank 8 through a duct 9, to again progress towards the roofing to enter it through the distributor duct 6 thus reinitiating the closed circuit solar energy pickup cycle. It is to be pointed out that although the tank 8 is permanently filled with the heat carrying fluid A such fluid is being continuously renewed since it flows as per a descending endless flow. Such flow is normally produced by the convection of the very heat carrying fluid A (thermosyphonic circulation), although it can be assisted, if such a thing is deemed necessary, by a pump (nor shown). As has been mentioned above, said pump can be driven by an alternating-current electric motor fed from the mains supplying the building, or it can be advantageously driven by a direct-current electric motor fed from a photovoltaic module station picking up the solar radiation energy and situated in an adequate area of the roofing. The cold water B of the secondary circuit enters in its turn said heat-exchange section of the inside of tank 8 through the bottom of coil 10 and flows upwards through this latter as it gradually warms up as it picks up the heat released by the heat carrying fluid A present in said tank, said water once warmed up and ready for consumption exiting said heat-exchange section through the top of said coil 10. If due to the use of the building, such as for example in the case of a building with several living quarters, it is desirable to have several independent secondary circuits one only heat-exchange section can be installed consisting in a tank 8 as that illustrated in Fig. 16 communicating with one or more primary circuits of heat carrying fluid A corresponding, for example, to one or more slopes of a roofing as per the invention but housing several, in the illustrated example seven, coils 10 with their corresponding inlets for the cold water B and outlets for the warm water B. Referring to Figs. 15 and 16 it is to be pointed out that in order to prevent heat losses it is convenient to heat-insulate as much as possible all parts of both the primary and secondary circuits. The layer 5 of heat-insulating material is thus arranged underneath the plate members 1 and longitudinal shapes 3 of the roofing. Tank 8 has an outer lining 12 and a cover 16 both made of heat-insulating material, and ducting 9 has a heat-insulating layer 13. Obviously other elements such as for example the distributor and collector ducts 6 and 7 and line sections of the secondary circuit outside the tank 8 can also advantageously be heat-insulated in spite of this not having been illustrated in the figures. The roofing is completed with several accessory elements such as a rain gutter 15 adjacent to the lowest level edge of each slope of the roofing, and a ridge cap member 14 fixed at the highest part of the roofing and covering in a waterproof arrangement the area of the tanks 8 and the highest ends of each slope.

Claims: A solar energy collector roofing for buildings of the type comprising a solar radiation pickup surface, provided to replace the roof, obtained from one o more heat-conductive, waterproof plate members (1) apt to be connected to each other thus establishing waterproof connections, and a plurality of channels formed by hollow longitudinal shapes (3) attached to or integrating said plate member(s) (1), said channels forming part of an open or closed circuit including one distributor duct (6) and at least one collector duct (7) to which said channels are communicating through its respective ends (3a, 3b), a heat carrying fluid (A) flowing through said circuit; characterised in that : said channels forming hollow longitudinal shapes (3) are at least in part directly exposed to the sun radiation; and all the members comprised in the roofing, namely said waterproof plate members (1) and said channels forming hollow longitudinal shapes (3), carry out a double function: on one hand a structural function as a support for the roof; and on the other hand an energy collecting function as solar radiation pickup surface and ducts for said heat carrying fluid (A) respectively, constituting together structural strengthening elements of the roof, being able to totally or in great part stand the design load stressing of said roofing. A roofing as per claim 1, characterised in that said distributor duct (6) and collector duct (7) accomplish also a structural function as a support for the roof. A roofing as per claim 1, characterised in that said hollow, longitudinal shapes (3) comprise tubular members (40) attached to said plate member (1) by welding or through the use of adhesive. A roofing as per claim 1, characterised in that said hollow, longitudinal shapes (3) are formed, at least in part, from the very material of said heat-conductive, waterproof plate member (1) by means of: a forming operation carried out upon said plate member (1) at several spaced regions to thus determine longitudinal channels (30) delimited by lateral edges (31); and closing said channels (30) through joining said lateral edges (31). A roofing as per claim 1, characterised in that said hollow, longitudinal shapes (3) are formed by members (50) of heat-conductive material and open cross-section, such as a "U" cross-section, attached to said heat-conductive plate member (1) at the edges (51) of the ends of its legs. A roofing as per claim 1, 2, 3, 4 or 5, characterised in that said plate member (1) besides comprises attached to it through welding and/or through the use of adhesive: a tube (60) functioning as said distributor duct (6) to which said first ends (3a) of the longitudinal shapes (3) are connected; and a tube (70) functioning as said collector duct (7) to which said second ends (3b) of the longitudinal shapes (3) are connected; in such a way that a circuit is formed for said heat carrying fluid (A) which specifically pertains to said plate member (1), with an inlet (61) into said tube (60) functioning as said distributor duct (6) and an outlet (71) out of said tube (70) functioning as said collector duct (7), said circuit being apt to form part of said open or closed circuit. A roofing as per claim 1, 2, 3, 4, 5 or 6, characterised in that said plate member (1) does besides comprise: a layer (5) of heat-insulating material such as a foamed polymer or copolymer, fiberglass, etc. lining its surface not exposed to the solar radiation, said layer of heat-insulating material also lining where applicable those walls of the longitudinal shapes (3) present in said surface; and a finishing plate or sheet (18) lining the open surface of said layer (5) of heat-insulating material. A roofing as per claim 4, characterised in that said closure of the channels (30) is carried out by joining said directly adjoining lateral edges or said spaced lateral edges (31) by means of an added member (32). A roofing as per claim 4, 5 or 8, characterised in that said attachment and/or joining is carried out through welding or through the use of an adhesive, said adhesive possibly being totally or partially formed by a layer of heat insulating material covering that surface of the assembly which is not exposed to the solar radiation. A roofing as per claim 1, characterised in that it includes a layer (5) of heat-insulating material such as foamed polymer or copolymer, fiberglass or the like lining the surface not exposed to the solar radiation of the assembly formed by the plate members (1), said layer being applied after the erection of said roofing by means of a lining procedure such as by plate fastening or spraying, with or without a finishing plate or sheet (18) lining the open surface of said layer (5) of heat-insulating material. A roofing as per claim 1, characterised in that it comprises one only distributor duct (6) and one only collector duct (7) for several of said plate members (1), said connection between the first ends (3a) of the longitudinal shapes (3) and said distributor duct (6) and between said second ends (3b) of the longitudinal shapes (3) and said collector duct (7) being carried out as a plug-in connection, a screw-in connection or an equivalent tight connection wherein rigid couplings (17) integral with one of the parts are pressed or screwed into or otherwise tightly connected with corresponding orifices equipped with a seal and provided in the other part, or by means of elastic couplings fixed at their ends to corresponding nipples integral with each of the parts. A roofing as per claim 1, characterised in that said circuit for the heat carrying fluid (A), of which distributor duct (6), longitudinal shapes (3) and collector duct (7) form part, is a closed primary circuit including at least one heat-exchange section comprising at least a tank (8), jacketed with a layer (12) of heat-insulating material, for a secondary circuit fluid, said at least one tank (8) carrying out a further function as structural support of the roof by totally or partially supporting the collector duct (7). A panel integrating a solar energy collector roofing for buildings, said roofing being of the type comprising a solar radiation pickup surface provided to replace a portion of the roof obtained from one heat-conductive, waterproof plate member (1) apt to be connected to other similar plate members of adjacent panels thus establishing waterproof connections, and a plurality of channels formed by hollow longitudinal shapes (3) attached to or integrating said plate member(s) (1), said channels forming part of an open or closed circuit including one distributor duct (6) and at least one collector duct (7) to which said channels are communicating through its respective ends (3a, 3b), a heat carrying fluid (A) flowing through said circuit; characterised in that : at opposed ends of said plate member (1) a tube (60) functioning as said distributor duct (6) and a tube (70) functioning as said collector duct (7) are attached and communicating with said channels through its respective ends (3a, 3b) thus forming a sub-circuit for said heat carrying fluid (A) specifically pertaining to said panel, with an inlet (61) into said tube (60) and an outlet (71) out of said tube (70), said specific sub-circuit being apt to form part of a general circuit that can be either open or closed, wherein said channel forming hollow longitudinal shapes (3) are at least in part directly exposed to the sun radiation, and all the main members comprised in the panel, namely said waterproof plate members (1), said channel forming hollow longitudinal shapes (3) and said tubes (60, 70) carry out a double function: on one hand a structural function as a support for the roof; and on the other hand an energy collecting function as solar radiation pickup surface and ducts for said heat carrying fluid (A) respectively, constituting all together a rigid assembly being able to totally or in great part stand the design load stressing of said roofing corresponding to the roofing surface area formed by said panel. A panel as per claim 13, characterised in that it does beside comprise a layer (5) of heat-insulating material such as a foamed polymer or copolymer, fiberglass or the like lining that surface of the plate member (1) which is not exposed to the solar radiation, and if said layer (5) of heat-insulating material is to be visible a finishing plate or sheet (18) lining the open surface of the former is preferably included. A panel as per claim 13, characterised in that it does besides comprise a lining of heat-insulating material such as a foamed polymer or copolymer, fiberglass or the like for said tubes (60, 70). A panel as per claim 13, characterised in that both said attachments to form or integrate the longitudinal shapes (3) with the plate member (1) and the attachments between the plate member (1) and the tubes (60, 70) and the connections of the first and second ends (3a) and (3b) of the longitudinal shapes (3) to the tubes (60, 70) are attachments and connections carried out through welding, through the use of an adhesive, through bead-jointing, through form fit or through combinations of these techniques, said attachments and connections being tight at the closures of said circuit for said heat carrying fluid (A).

Inventors: GARCIA CORS JOSEP, OISTRACH GARCIA DE CASTRO EDUA, GARCIA CORS, JOSEP, OISTRACH GARCIA DE CASTRO, EDUARDO
Applicants: BIOHABITAT SXXI S L, BIOHABITAT SXXI, S.L.
Application year: 1999
Main classification: F24J2
IPC codes: F24J2