SYSTEM FOR HEATING INDOOR AREAS BY ELECTRICITY WITH "SANDWICH"-TYPE STRUCTURES

Abstract: System for heating indoor areas comprising "sandwich"-type structures (182) on at least one face of which turned towards the indoor area are metal sheets (184) which turn the structural parts into heating parts as well as by an increase in temperature, even only of a few degrees, compared with ambient temperature, of said metal sheets (184), said increase being obtained by closure of an electric circuit (190-191) by means of said metal sheets (184).

Description: SYSTEM FOR HEATING INDOOR AREAS BY ELECTRICITY WITH ' SANDWICH '-TYPE STRUCTURES Innumerable processes and means are adopted for heating indoor areas by the generation of heat ,being .'essentially based on combustion, especially of gas, and on electric heating elements. In either case a thermal chain is created that places its limits on the thermal efficiency of the system. In the first case, for example, a combustible gas is used to feed a burner and the flame so produced trans¬ forms the energy derived from the gas into heat which heats water in a boiler connected to radiators. While circulating this water heats the radiators which in turn warm the air close to their surfaces. Heated air being lighter, this rises drawing in cold air which the radiators then heat as before. A convective movement of air is thus created to warm the surrounding environment. In an example related to the second case electric current circulates in the heating elements, so transforming electric energy into thermal energy. These resistances, or elements, reach very high tempera¬ tures, up to 500°C, and on warming the air close to them create the convective movement that transfers heat to the surrounding space. In both cases there are clearly considerable losses in the whole thermal chain ,especially due to the considerable differences between temperature of the flame or of the electric element compared with the surrounding temperature. Particularly as regards heating by electricity a double thermal head is created and consequently double the loss of efficiency; the loss occurring while heating the ele¬ ments and that which takes place when heat is transferred from these elements to the surrounding atmosphere. There is a further loss in efficiency during the necessary diffusion of heat from the small bulk of the electrical elements and that so enormously greater of the space to be heated. The result is that the energy used in relation to that available and consumed is very low. For certain purposes electric energy is transformed into thermal energy by very thin elements which may even be suitably cut sheets, this being done to raise the value of their electrical resistance. But none of the systems hitherto invented have enabled large scale and universal applications to be made since, from the economic and energy standpoints, they have not solved the problem raised by the thinness and therefore the fragility of the heating elements. Solutions adopted such a glueing heating elements onto plastic, cardboard or fibrous bases have prevented a high thermal yield because of the thermal barrier formed by such supporting materials or by the glue. A good electrical insulator is also a good thermal insu¬ lator. This thermal insulator considerably reduces the thermal yield of the apparatus or system. Subject of the invention is a system for heating indoor areas consisting of structures composed, or comprising composed structures, for the formation of walls, roofs, partitions, ceilings, insulation, ducts, services, fur¬ niture, decorative means and for any other purpose, said composed structures comprising, at least on one surface facing towards the indoor space, metal sheets for reac¬ tion to stresses, for decoration, containing, strengthening or for any other purpose. Heating is produced by causing the structural parts to become heating elements as well by an increase in tempera¬ ture, even if only a few degrees higher than that in the area, of one or more of said metal sheets, generated by completion of an electric circuit. The electric circuit can be closed by series or parallel connection of one or more of said metal sheets and using suitable strengths of electric current to produce a good level of warmth in the indoor areas concerned even without any further heating means. Heating is produced by radiation. The structures concerned may be fixed or moveable and may be prefabricated. These structures can be carrying and self-carrying and of the 'sandwich' type with at least one sheet of metal placed outermost. The material inside the structures is light and may even be f1 imsy . The internal material concerned may be foam phenolic resin, extruded polyethylene, foam polyurethane , glass wool or of some other type as circumstances dictate. The structure can be in sheets or volumetric. The metal sheets through which the electric circuit is closed may be of aluminium or some other electrically conducting material. The metal sheets can be a few microns thick. The metal sheets can be continuous and the electric circuit be closed by means of bars fixed to the opposite ends of said sheets along their entire length. Parallel cuts may be made in the metal sheets, these cuts extending alternat ingly from one side to a short distance from the opposite one and from there to a short distance from the first side, and so on. This will form a continuous serpentine of substantially constant width, for closing the electric circuit. Alternatively the metal sheets may be cut in a circular or polygonal spiral to form a circular or polygonal spi¬ ral band, the circuit being closed through said spiral. Alternatively again the metal sheets are given one or more parallel axial cuts so as to form two or more paral¬ lel strips of equal width electrically connected one to another in series or parallel and then put into the circuit The electric circuit may be closed by an additional thin metal body matching with the metal sheets of the structure. This matching between the additional metal body and the metal sheets of the structure is done by interposing a means of insulation, which may be a paint or an anodized layer formed on the metal sheet of the building structure or on the additional sheet of metal. The additional metal body may be a sheet or a band laid serpent inewise or in a spiral or in some other way, or it may consist of several strips laid side by side. The structure may be modular. Two or more structures may be connected electrically to¬ gether, in series or parallel, and then included within the electric circuit. If the bodies through which the circuit passes are strips, two or more of these in adjacent structures can be series connected electrically so as to close the circuit with the band formed by the set of connected strips. The electric circuit passing among the metal sheets can be closed by connections that cross through the insulating layer in the structures. If made in suitable sizes connections between the metal sheets and the electric circuit can also serve to hold the structures to the various parts of the building, in particular to the ceilings. The invention offers evident advantages. While presently known electric heating has to reach high temperatures in low-conducting materials, these being electric resistances or elements, and then diffuse warmth throughout the indoor area, this invention in practice uses the small thermal head generally produced by the passage of current in conducting elements closed in a circuit . For this purpose use is made of thin conducting elements, ones with a high ratio between their area and thickness. Because these bodies are flimsy, supporting means are found among those normally present in structures and in such indoor areas generally. For purposes of generating heat, therefore, any metal sheet, band or the like can be used, such as are comprised in any fixed or moveable structure in such areas by making current pass through these metal bodies. Bearing in mind the very considerable use made in some places, especially in industrial buildings, showrooms and offices, of insulating structures clad or associated to metal sheetings of the 'sandwich' type and similar ones, es ecially in the form of panelling of various kinds, it is clearly possible to connect, in series or in parallel, part or all of such sheets to obtain bodies in the form of bands or of sheets of considerable size and length. Using certain values of electric current and closing the circuit at the two ends of such bodies, a satisfactory degree of warmth can be reached at minimum thermal inertia without any special arrangements having to be undertaken since the low temperatures at which the heating bodies operate, even only a few degrees higher than ambient temperature, require no special insulation or repairs for wear and for replacement of parts. The structural parts themselves become heating elements by simply connecting them up to a source of electricity. Presently used fluid-operated or electric heating systems thus become unnecessary or in any case irrational as in the case described heating systems are replaced by the structures of the building itself which generate heat by merely plugging them in to a source of electricity. All this is achieved with a negligible amount of effort and minimum technical and economic expenditure. Diffusion of warmth in the heated place is practically instantaneous , as soon as the heating is turned on. The foregoing is substantially valid even if additional thin metal heating bodies are matched with the metal bo- dies associated to the structures. Structural laminar bodies support and protect the heating bodies added and diffuse their heat. Heating obtained by the present invention may therefore be obtained : - without costly means of support and protection against high temperatures, - by drastically reducing the losses sustained due to high thermal heads and heat diffusion by convection, - utilizing existing structures and furniture. The flow of energy is substantially propagated by elec¬ tromagnetic waves, in a direct line, becoming heat in the bodies such waves encounter. There is practically no effect on the air the temperature of which remains lower than that of the absorbing bodies. In industrial buildings and warehouses, the proposed pa¬ nels can replace presently used aluminium, plaster or other types of ceiling panels. If laminar metal bodies, especially of anodized aluminium, are used as supports for the heating elements, a high degree of electrical insulation is established between heating elements and supporting material without creating a thermal barrier. In this way maximum protection is given to heating elements even if very thin, without simultaneously raising obstacles to the diffusion of heat, and producing a very high level of thermal efficiency. The heating elements are completely static and no kind of maintenance is required for these materials. Consumption of electricity is so low as to make running costs extremely competitive even compared with the least expensive conventional systems, such as gas heating. Plant is cheap both to install and to operate; similar to conventional electrical heating, it can be centralized as the operative level is reached almost ins antaneously. The invented system may be summed up by stating that it transforms electrical energy into diffused warmth making use of existing structures, occupying minimum space, ope¬ rating at low thermal inertia, consuming little energy, of-fering a high degree of security. Characteristics and purposes of the invention will be made still clearer by the following examples of its execution illustrated by diagrammat ically drawn figures. Fig.1 Perspective view from above of a continuous radia- ing panel . Fig.2 Panel with a serpentine radiating body obtained by alternat ingly placed cuts on a sheet of aluminium. Fig.3 Panel with a spirally radiating body obtained by cutting a sheet of aluminium in this way. Fig.4 Pair of rectangular panels with serpentinewise ra¬ diating bodies obtained by parallel strips joined at the ends . Fig.5 Radiating false ceiling to a room made by serpen- tinewise electrical connection among panels. Fig.6 Industrial building heated by ' sandwich ' -type struc¬ tural parts forming the roof, electrically connected in the form of a serpentine. Fig.7 An industrial building substantially like that in Fig.6, but with an arched roof. The panel 10 is composed of a phenolic resin foam insulating sheet 11 associated by welding aluminium sheets 14 and 15 onto surfaces 12 and 13 respectively. Oblong brass plates 16 and 17 are placed in contact with the ends of sheet 14 corresponding to the front face 12 that will be directed towards the area to be heated. Brass bars 18, 19 are fixed respectively to said plates, and through holes 20,21 in sheets 11, these bars emerge onto the back face of the panel 15. Said bars are connected to the ends 22, 23 of an electric circuit 24 and can be used to hole the panel to the ceil¬ ing 25. When electric current passes through sheet 14, it becomes a thin but extensive resisting body which radiates heat towards the room. The panel 31 in Fig. 2 is substantially similar to panel 10 in Fig. 1 and forms part of the ceiling 30. It is composed of the insulating phenolic resin sheet 32 to which a sheet .of aluminium 34 is welded on the lower face 33. In said sheet is a set of parallel cuts, such as 35 and 36, and these form a serpentine 37 in the sheet, with ends 38 and 39. In contact with these ends are the small brass blocks 40 and 41 respectively fixed to bars 42 and 43 that emerge from the upper face ' of the panel and permit connection to the terminals 44 and 45 of the electric circuit 46. The serpentine therefore provides an extensive thin re- siεtent body that diffuses warmth. The panel 50 in Fig. 3 is similar to the former ones and exhibits an insulating filler sheet 51 between the upper 52 and lower 53 metal sheets. In the lower sheet 53 there is a continuous spiralling cut 55 forming a square spiral 56 with ends 57 and 58. These ends are placed in contact with the brass blocks 60 and 61 fixed to the bars 62 and 63 that emerge from the upper face 64 of the panel permitting connection to the terminals 65 and 66 of the electric circuit 67. The spiral 56 therefore produces a long thin resistent body that diffuses warmth. Fig.4 ' illustrates the formation of a thermal strip 69 applied to the ceiling 90 and made of panels 70 and 80 similar to those already described but oblong in shape and laid side by side. The filler sheet 71 for the panel 70 connects the two rectangular sheets of aluminium 72 and 73 welded to the upper and lower faces 74 of said sheet. Longitudinal parallel cuts 75 have been made on the sheet 73 thus forming substantially equal strips 76. The filler sheet 81 for the panel 80 connects the two rectangular sheets of aluminium 82 and 83 welded onto the upper and lower faces 84 of said sheet. Longitudinal parallel cuts 85 have been made on the sheet 83 thus forming substantially equal strips 86. In each panel the various sets of strips 76 and 86 are connected together in pairs by crossing brackets 91, 92. Said sets of strips 76 and 86 have been further joined longitudinally by the intermediate brackets 93. In this way a serpentine%is formed as shown by the dotted line 94. At the ends 97, 98 of the serpentine contact with the blocks has been made by ducts 100 to which are fixed the bars 101 and 102 that cross the filler sheet 71 and come out on the upper face. Said bars have been connected- up to the terminals 105 and 106 of an electric circuit 107. It will be seen fromthe foregoing that an electrically continuous band is obtained, having a constant section, formed by the sum of the strips 76 and 86 which, acting as electric heating elements, heat up and diffuse warmth. Fig.5 shows a room 110 whose ceiling 111 has been covered by panels 112 substantially the same as panels 31 in Fig.2 on which are two sets of serpentinewise sheets 120, 130. The various serpent inewise sheets 120, 130 have been con¬ nected at their ends by crosswise brackets 121 and 131. The two sets of serpent ines have been connected together by ^ the longitudinal bracket 132 forming serpentine 135. The other ends 133, 134 of the two sets of serpentine sheets 120 and 130 have been joined to the blocks 135 and 136 respectively fixed to the bars 137 and 138 which, having crossed the insulating sheet 139 > have been con- nected to the terminals 140 and 141 of an electric cir¬ cuit fed by the line 142 served by a switch 143. It will be seen that an electric heating element has been obtained formed by the serpentine 135 that diffuses heat throughout the Toom 110 by radiation. Fig.6 illustrates an industrial building 150 ith a roof 151 for a room 152. The roof 151 is made from a set of sandwich-type panels 155 laid side by side. Said panels have an internal layer of light laminar 156 consisting of phenolic foam resin. Above this are laid overlapping sheets 160 of aluminium . Underneath aluminium sheets like 161 are welded to the insulating layer. It will be seen that said sheets 161 are connected one to another by..their., long sides but are insulated on the sides 162 from the adjacent ones. At their ends the lines of panels are joined in pairs by metal bridging brackets 163. Thus a continuous serpentinewise band 170 is fromed by the various panels laid side by side, said serpentine starting at the end 171 and ending at the end 172 as shown by the dotted line 173 - Said ends are joined to the terminals 174, 175 of an electric circuit fed by the line 176, served by the switch 177. Completion of the electric circuit gives rise to uni- fbrm heating of the aluminium band so obtained, and diffusion of warmth towards the room 152. Fig. 7 illustrates an industrial building 180 with an arched roof 181 over an internal space 200; This roof is made from a number of prefabricated arches formed of sandwich-type structures 182 comprising metal sheets 183, 184 on both the inner and outer sides of an insulating layer 188. The series of metal parts 184 form. a .:sύbεtantiaLly"contin¬ uous band 185. By connecting the terminals 190, 191 of an electric cir¬ cuit fed by the main electricity supply 1 ?2 served by a switch 193, to the two ends 186, 187 of said band 185 or to the ends of a serpentine 189 formed by applying the bridging brackets 185, 186 to alternate ends of a number of bands 185 present in the roof, it becomes pos¬ sible to transform said metal bodies in generators of heat for warming, as desired, the whole building 180. Electrical connections can be already placed within the prefabricated structure before the roof is put on, or else they can be added during mounting to have electric current circulating either in some metal parts inside the roof or even over its whole surface according to the effects it is desired to achieve and especially to the temperatures required in the various areas under the roof. As the roof structure is prefabricated and self sup¬ porting and as there is already continuity at least on the parts belonging to the various arches forming the roof, it will be seen how easy it is to give these structures a double purpose ,namely that of the ordinary protection provided by a roof but simultaneously heating of the inside of the building and therefore making it possible to avoid the considerable expense of a separate heating system of the conventional kind. As the invention has been described and explained solely as an example of its use not limited to this and to show its essential features, numerous variations may of course be made to it according to industrial, commercial or other requirements and other systems and means included in it without causing thereby a departure from its sphere of operation. It must therefore be understood that the request to pa¬ tent comprises any equivalent application of the concepts and any equivalent product executed and/or in operation according to any one or more of the characteristics set forth in the following claims.

Claims: CLAIMS 1. System for heating indoor areas ( 110 , 152 , 200) by structures composed or comprising structures ( 10,31,50, 70,80, 112, 155, 182) composed for the formation of walls, roofs ( 151, 181), partitions, for ceilings (25,30,90), insulation, ducts, services, furnishings, decorations and for any other purpose, said composed structures com¬ prising at least on one surface ( 12,33,74,84) facing to¬ wards the indoor areas ( 100, 152,200), metal sheets ( 14, 34,53,73,83, 120, 130, 161, 184) for reaction to stresses, embellishment, containing, strengthening and for any other purpose, characterized in that the heating is obtained by causing the structures ( 10,31,50,70,80, 112, 155, 182) to become heating elements as well by increasing the temperature, even if by only a few degress compared with that of the indoor area ( 110 , 152 , 200), of one or more of said metal sheets ( 14,34,53,73,83, 120, 130, 161, 184 ), said increase in temperature being generated by closure of an electric cir- cuit (24,46,67, 107, 140-141, 174-175, 190-191). 2. System as in claim 1 characterized in that the electric circuit (24, 6,67, 107, 140-141, 174-175, 190-191) is closed by one or more of said metal sheets ( 14,34,53,73,83, 120, 130, 161, 184) with series or parallel connection and with suitable values of electric current to obtain, without taking any further action, optimum heating of said indoor areas (110, 152,200). 3. System as in claim 1 characterized in that heating is provided by radiation. 4. System as in claim 1 characterized in that the structures ( 103,50,70,80, 112, 155, 182)are fixed or moveable, as the case may be. 5. System as in claim 2 characterized in that the structures ( 10,31,50,70,80, 112, 155, 182) are prefabricated. 6. System as in claim 1 characterized in that the structures are carrying struc¬ tures . 7. System as in claim 1 characterized in that the structures are self-bearing. 8. System as in claim 1 characterized in that the structures ( 10,31,50,70,80, 112, 155 , 182) are" of the ' sandwich '-type and that at least one of the external sheets ( 14,34,53,73,83, 120, 130, 184) are me al . 9. System as in claim 1 characterized in that the internal material ( 11,32,51, 71,81, 133, 156, 188) of the structures ( 10,31,50,70,80, 112, 155, 182) is light. 10. System as in claim 9 characterized in that the internal material ( 11,32,51, 71,81, 133, 156, 188) of the structures ( 10,31,50,70,80, 112, 155, 182) is flimsy. 11. System as in claim 9 characterized in that the internal material ( 11,32,51, 71,81, 133, 156, 188) of the structures ( 10,31,50,70,80, 112, 155, 182) is phenolic foam resin. 12. System as in claim 9 characterized in that the internal material ( 11,32,51, 71,81, 133, 156, 188) of the structures ( 10,31,50,70,80, 112, 155, 182) is extruded polyethylene. 13. System as in claim 9 characterized in that the internal material ( 11,32,51, 71,81, 133, 156, 188) of the structures ( 10,31,50,70,80, 112, 155, 182) is foam polyurethane . 14. System as in claim 9 characterized in that the internal material ( 11,32,51, 71,81, 133, 156, 188) of the structures 10,31,50,70,80, 112, 155, 182) is glass wool. 15. System as in claim 1 characterized in that the structures ( 11,32,51,71,81, 133, 156, 188) are in sheet form. 16. System as in claim 1 characterized in that the structures are volumetric. 17. System as in claim I characterized in that the metal sheets (34,53,73,83,120, ;1.30, 3:6.J, 184 ) through which the electric circuit (24,46, 67, 107, 140-141, 174-175, 190-191) are of aluminium. 18. System as in claim 1 characterized in that the thickness of the metal sheets is of a few microns. 19. System as in claim 1 characterized in that the metal sheets ( 14) are continuous and in that the electric circuit (24) is closed by plates ( 16, 17) fixed at opposite ends of said sheets across their entire width. 20. System as in claim 1 characterized in that the metal sheets (34) have made in them a set of parallel cuts (35,36) that extend alterna- tingly from one side to a short way from the opposite one and from this latter a short way from the first side and so on, forming a continuous serpentine (37) of a substan¬ tially constant width, the electric circuit (46) being closed through said serpentine (37). 21 • System as in claim 1 characterized in that the metal sheets (53) are given a circular or polygonal spiral cut (55) that produces a circular or polygonal spiral band (56), the electric circuit .(67) .being.'dosed through said spiral (56). 22. System as in claim 1 characterized in that the metal sheets (73,83) are given an axial cut or a number of parallel cuts (75,85) so as to form two or more parallel strips (76,86) of equal width that are electrically connected up in series or in parallel and then put into the electric circuit ( 107). 23. System as in claim 1 characterized in that the electric circuit is closed by means of an added thin metal body made to match with the metal sheets in the structures. 24. System as in claim 23 characterized in that when matching the added metal body with the metal sheets in the structures an isolating means is placed between said body and said sheets. 25. System as in claim 24 characterized in that the isolating means is a paint. 26. System as in claim 24 charac erized in that the isolating means is an anodized layer created on the metal sheet in the building structures or on the added metal body. 27. System as in claim 23 characterized in that the added metal body is a sheet. 28. System as in claim 23 characterized in that the added metal body is in the form of bands laid serpentinewise or spirally or in other ways. 29. System as in claim 23 characterized in that the added metal body is formed of a number of strips laid side by side. 30. System as in claim 1 characterized in that the structures ( 10,31,50,70,80, 112, 155, 182) are modular . 31. System as in claim 1 characterized in that two or more structures ( 10,31,50, 70,80, 112, 155, 182) are electrically connected together in series or parallel and then put into the electric circuit (24,46,67, 107, 140-141, 174-175, 190-191). 32. System as in claims 22 and 29 characterized in that the ends (97,98, 171, 172, 186, 187) of two or more strips (76,86, 161, 185) in two or- more adjacent structures (70,80, 155, 182) are electrically connected together in series so as to close the electric circuit ( 107, 174-175, 190-191) with the band formed by the set of connected strips. 33. System as in claim 1 characterized in that the electric circuit (24,46,67, 107) is closed among the metal sheets ( 1 ,34,53,73,83) by connecting means ( 19,20,42,43,62,63, 101, 102, 134, 135) that pass through the isolating layer ( 11,32,51,71,81, 133) in the structures ( 10,31,50,70,80, 112). 34. System as in claim 33 characterized in that the connections between the metal sheets and the electric circuit are so sized as to ensure that the structures are firmly held to the various parts of the building and especially to the ceilings.

Inventors: STABILE ALDO, STABILE, ALDO
Applicants: CADIF SRL, STABILE ALDO, CADIF S.R.L., STABILE, ALDO
Application year: 1995
Main classification: F24D13
IPC codes: F24D13