Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D13/00—Electric heating systems
  • F24D13/02—Electric heating systems solely using resistance heating, e.g. underfloor heating
  • F24D13/022—Electric heating systems solely using resistance heating, e.g. underfloor heating resistances incorporated in construction elements
  • F24D13/024—Electric heating systems solely using resistance heating, e.g. underfloor heating resistances incorporated in construction elements in walls, floors, ceilings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]

Definitions

• the invention relates to a facade heating arrangement
• a facade heating arrangement comprising a supporting structure that can be fastened to a wall, usually an outer wall, of a building and which con ⁇ tains profiles, or mullions, usually of metal, particularly aluminium extrusions.
• the profiles are usually arranged as vertical or upright metal section horizontal metal section members or cross members.
• the structure is connected to and thermally insulated from a facade skin that comprises the uprights and cross members of the outer wall and the window, usually formed from double glazed panels.
• the facade heating arrangement also comprises a heating device for heating the supporting structure.
• a metal facade construction of this type is known, for example, from German Patent Specification 21 32 921.
• the heating device of the known construction is formed by a hot water circuit which extends through cavities of the metal section uprights and metal section cross members. Owing to the thermal separation between the facade skin and the supporting structure of the facade construction formed by the uprights and cross members, the supporting structure forms a heating body of large area radiating heat substan ⁇ tially only towards the inside of the building, so that, with an appropriate supply of hot water, a building heating system obtained that can be used for a transition or warm up period, or as an additional heating system that cooperates with other heating systems.
• t e invention is intended to solve the problem of so contructing a facade heating construction of the general type described initally that a special, imper ⁇ meable contruction of the connection between the uprights and the cross members is not necessary, that maintenance and repair work on the heating device and also on the entire facade construction is simplified and a good controllability is achieved that is not dependent on the position of indiv- vidual temperature sensors, for example on the sunny side or shaded side of the building.
• a facade heating arrangement comprising a thermally conductive support structure arranged to be mounted on the inside of, and to extend away from, a wall of a building adjacent a window therein, and heating means arranged to effect thermal transfer to the support structure and thereby to the atmosphere in front of the window, wherein the thermally conductive support structure comprises an elongate profile having a groove therein, the heating means comprises an elongate electrical heater that has a negative temperature coefficient of heating capacity, and wherein the heater is mounted in the groove so as to effect good thermal transfer from the heater to the profile.
• a method of heating the atmosphere inside a building adjacent a window in a wall thereof wherein a thermally conductive support structure is mounted on the inside of said wall adjacent the window so as to extend away therefrom, wherein an elongate heater having a negative temperature coefficient of heating capacity is mounted in a groove of an elongate profile of the support structure so as to effect good thermal transfer to the pro ⁇ file and thereby to the atmosphere adjacent the window.
• the heater comprises a heater cable having a positive temperature coefficient (PTC) of resisti ⁇ vity, and comprises an elongate cable having -a pair of parallel stranded metal bus bar conductors enclosed within a conductive polymeric material having a PTC characteristic, and surrounded by an insulating jacket.
• PTC positive temperature coefficient
• the construction of the electrical heating device described herein makes is possible also to carry out repair work in specific areas of the facade without it being necessary to shut down the heating device in the other heated parts of the facade. So called hot spots on the heat-radiating sur ⁇ faces of the uprights and cross members that face the interior of the building are avoided by virtue of the self- regulating property of the heating cable arising from its PTC characteristic.
• This heating cable is preferably arranged in such a manner that is two stranded conductors which run parallel to and spaced from each other by being embedded in a conductive polymer can be supplied, for example, by 220 volt alternating current.
• the temperature-sensitive resistance material located between the heating cables forms the heat-resistance over the entire length of the heating cable.
• This heat-resistance may be considered as a number of heat-resistance elements connected in parallel with each other which, owing to the positive temperature coefficient of their resistance, effect the self-regulation of the heating cable by means of those heat-resistance elements which adopt higher temperatures owing to thermal irregulari ⁇ ties in the system increasing their resistance value, reducing the current passing through them and, thereby, decreasing the reduction in the heating capacity in the relevant heat-resistance element in order to lower the tem ⁇ perature.
• a polymeric carrier matrix which contracts on cooling and expands on heating contains conductive par ⁇ ticles, especially carbon particles, which come increasingly into contact on cooling to produce more conductive pathways, but, on heating, are drawn apart and increasingly lose con ⁇ tact with each other with a reduction in the overall effec ⁇ tive conductor cross-section.
• Each individual section of the heating cable has this self-regulating property over its entire length, so that no separate control circuits, such as thermostats, are required in order, for example, to adjust the heat energy delivered for each portion of the facade according to whether the respective portion is on the sunny, shady or windy side of the building or is located in a region of the building in which additional heat sources operate.
• the self-regulating property of the heating cable can be obtained also with other physical principles or mecha ⁇ nisms.
• a lossy dielectric having a negative temperature coefficient of power loss may lie between the conductors of the cable, or heating conductors having a pronounced posi ⁇ tive temperature coeficient of resistance may be wrapped in the form of a helix around connection conductors extending on opposite sides of a spacer strip, so that the individual portions of the helix between the connection conductors form the parallel-connected heating elements.
• the heater used in the present invention may be a self- regulating heater sold by the Chemelex Division of Raychem, and preferably is selected, according to the power output required, form Raychem's QTV range, for example a 10 QTV 2 or a 15 QTV 2 heater.
• suitable heaters for use in the present invention are described for example in Raychem's US Patent Nos. 4188276, 4459473, and 4426339, the entire contents of which are included herein by this reference.
• the heaters may be enclosed within a metal braid or foil for earthing and/or enhancing thermal transfer.
• the support structure will comprise one or more, and usually four, profiles that form a closed, usually rectangular, loop for mounting around a window.
• Each pro ⁇ file may contain a separate heating element, or a single heater may extend along the lengths of each of the profiles.
• the size, i.e. total length, of the support structure will, of course, depend on the size of the window, and it would extend away from the wall into the room typically for a depth of about 15 centimetres.
• the thermal transfer mecha ⁇ nisms are typically thermal conduction from the heater into the support structure profiles, usually an aluminium or other metal extrusion, and then radiation, and/or convec ⁇ tion, from the support structure inwardly towards the air in front of the window.
• the depth of the support structure will accordingly be chosen in dependence on the surface area of the window so as to maintain a specified minimum tem ⁇ perature, of say 18°C at the centre of the window.
• the heater may be mounted as a snap-fit into the groove, so that the good mechanical retention will enhance the thermal transfer. Thermal transfer from the heater may be further enhanced by embedding the heater in a potting compound or other material having good thermal conductivity.
• the groove containing the heater may be closed by a cover, which may itself be a snap-fit on or in the groove, or may be secured by clips or screws.
• the groove or grooves containing the heater or heaters open into the room so that should any maintenance or replacement of the heating system be necessary, access thereto is easily obtained without disturbing the mounting of the support structure on the wall.
• the support structure When the support structure is mounted on the wall, it is preferred that it be thermally insulated therefrom, thereby to enhance the proportion of heat that is radiated across the surface of the window.
• Fig. 1 shows a horizontal section through the metal facade construction, in the region of a upright; it should be mentioned that the view in Figure 1 may also be regarded as a ver ⁇ tical section through the metal facade construction in the region of a horizontal cross member;
• Fig. 2 shows a cross-section of a modification of
• Fig. 3 shows a cross-section of a further modifica ⁇ tion of Figure 1;
• Fig. 4 shows a cross-section of a part of a metal facade construction in which the metal sec ⁇ tions of the supporting structure which form the uprights have been omitted, wherein that part of a profiled framework which lies on the inside of the building and which is thermally insulated towards the outside of the building is to be regarded as a cross member which is provided with grooves opening towards the inside of the building for receiving heating cables;
• Fig. 5 shows a schematic equivalent circuit diagram of a heating cable portion
• Fig. 6 shows an enlarged view in section of a part of a upright or cross member in the region of a profile groove containing a heating cable
• Figs 7 & 8 show enlarged views in section of modified embodiments of Figure 6;
• Figs. 9 show a range of other shapes of profile to 13 grooves with heating cables extending therein showing, in section, part of the corner region of a cross member or upright; and
• Fig. 14 shows a section through a upright or cross member to which the grooves carrying the heating cables have been fitted by fastening a groove carrier.
• two adjacent double glazing panels are designated 1 and 2.
• the insulating glass panels 1 and 2 are held between a metal framework 3 on the inside of the room of a building and a metal framework member 4 on the outside of the room.
• Elastic mounting elements 5 and 6 separate the framework members 3 and 4, which are clamped together, for example, by means of screws. Details of this arrangement have been omitted from the drawing for the sake of clarity since they are known to a person skilled in the art.
• a cover 7 is clipped, using suitable locking means, on to the outer framework member 4 over the exposed fastening points.
• the elastic mounting elements 5 and 6 form a first thermal insulation of the metal facade construction, this thermal insulation acting between the outer framework member 4 and the inner framework member 3.
• a second thermal insu ⁇ lation of the metal facade construction is provided between the inner framework member 3 and a hollow section 8 of substantially rectangular cross-section which forms an upright member (or alternatively a cross member), and takes the form o.f two insulating webs 9 and 10 made of high- rigidity plastics material which are each anchored by dove ⁇ tail extensions in correspondingly constructed grooves of the metal sections 3 and 8.
• the hollow sec ⁇ tion 8 On its innermost side within the room, the hollow sec ⁇ tion 8 is provided with grooves 11 and 12 which open towards the inside of the building and which, in the embodiments shown in Figures 1 to 3, are formed by flanges projecting away from the inside profiled outer surface of the box sec ⁇ tion. According to an alternative embodiment (not shown in the drawings) these grooves may, however, also be positioned inside the rectangular outer contour of the hollow section 8.
• Heating cables 13 and 14 which are generally dumb-bell shaped in cross-section extend inside the grooves 11 and 12, repsectively, in the longitudinal direction of the hollow section 8, which heating cables fill the relevant groove to provide a good transfer of heat between the heating cables and the hollow section 8.
• a cover strip 15 of U- shaped cross-section is clipped on to the hollow section 8 in the manner shown in Figure 1, which cover strip is constructed in such a manner that substantially closed, smooth outer surfaces are produced on the sides and at the end face of the hollow section 8.
• the inner cover strip 15 corresponds in shape substantially to the outer cover strip 7, and it is possible to use identical covers in order to simplify manufacture and make storage cheaper.
• Figure 6 shows the detail designated E in Figure 1 on an enlarged scale and again shows the cover strip 15 and the groove 12 which is formed between the flanges projecting above the outer surface of the hollow section 8 on the inside of the building.
• the flange located near the corner of the hollow section 8 is provided on the outside with a longitudinally extending channel in which an engaging strip of one limb of the cover strip 15 has been engaged.
• the heating cable 14 which, owing to the appropriate sizing of the groove 12 with respect to the cross-section of the heating cable, rests against the side walls and on the base of the groove and is spaced at a slight distance from the cover strip 15, so that a good transfer of heat to the parts of the metal section adjacent to the heating cable is brought about by thermal conduction and/or thermal radiation.
• the stranded conduc ⁇ tors 16 and 17 of the heater cable 14 and the heating conduc ⁇ tor material 18 whch surrounds and connects them are covered by an insulation sheath 19 which ensures electrical insula ⁇ tion with respect to the metal profiles without signifi ⁇ cantly hindering the transport of heat.
• Figures 7 and 8 show embodiments in which a self- regulating heating cable is placed in a metal profile groove and the groove opening has then been closed by a com ⁇ paratively narrow cover strip 20 or 21, it being possible for the cover strip 20 or 21 to be locked on the groove opening in the manner shown in Figures 8 and 9.
• the cover strip 20, which may be made of metal or of a heat-conductive plastics material, is so dimensioned on its inwardly facing side that it is contiguous with the upper end of the heating cable cross-section, for example of the heat cable 14, in order to conduct heat away.
• a further improvement in the removal of heat from the heating cable to the adjacent sur ⁇ faces of the parts of the metal profile is achieved in the embodiment shown in Figure 7 by a casting compound 22 having good thermal conductivity, in which the heating cable is embedded inside the profile groove.
• a metal foil sheath 23 on the heating cable likewise serves to improve the transfer of heat between the heating cable and the adjacent surfaces of the metal profile.
• This form of construction is suitable for those uprights and cross mem ⁇ bers of a metal facade construction that are situated imme ⁇ diately in front of a ceiling or an internal wall of a building, so that the grooves are freely accessible for receiving heating cables in the hollow profile 8.
• Figure 4 shows a metal facade construction in which grooves 32 and 33 which receive heating cables are located, in a manner corresponding to the construction of the grooves 11 and 12 in the embodiment shown in Figure 1, on the surface of the metal framework member 34 that faces the inside of the building, which framework member corresponds to the framework member 3 of the embodiment shown in Figure 1.
• the heat produced by the heating cables at the inner framework member 34 substantially is not conducted towards the outside of the building to the framework member 35 but is effective for radiant heating of the interior of the building.
• Figures 9 to 13 show further embodiments of grooves fitted to the metal uprights (profiles) and/or the metal cross members (profiles).
• These grooves are each an integral component of the relevant metal profile and are adapted to the particular cross-sectional shape of the heating cable.
• a heating cable of circular cross-section is used, but it should be pointed out that heating cables of rectangular or oval cross-section may also be used.
• the grooves receiving the heating cables are fitted to the rele ⁇ vant upright or the relevant cross profile in such a manner that the grooves open towards each other and the heating cables are pushed into the grooves outwards from the centre of the enclosure formed around the window by the profiles, or mullions.
• Figure 13 shows the larger cross-sectional dimension of the ribbon-shaped heating cable oriented perpendicular to the plane of the facade. It will be seen that, in this embodiment, the groove receiving the heating cable is com ⁇ paratively flat. At the transition of the groove from a upright to a cross member in the corner region of the sup ⁇ porting structure, the ribbon-shaped heating cable can be bent easily and does not need to be bent on its edge.
• a heating cable carrier 44 is in the form of a correspondingly shaped metal profile strip containing the heating cables 40 and 41 in grooves 42 and 42, respec- tively, which open at the side.
• the carrier 44 is fastened, for example firmly screwed, to the hollow section 8 of a upright or cross member.
• the entire arrangement can be covered by a cover strip 45 in the manner shown, the cover strip 45 also serving to close off the profile grooves 42 and 43.
• the embodiment shown in Figure 14 has the advantage that even already erected facades can subsequently be equipped with a heating device of the kind described herein, so that this embodiment is suitable for reconstruction measures.
• Thermally conductive inserts between the hollow section 8 and the heating cable carrier 44 are able to ensure a good transfer of heat as result of a reliable mechanical contact between these parts.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Installation Of Indoor Wiring (AREA)
• Load-Bearing And Curtain Walls (AREA)
• Central Heating Systems (AREA)
• Building Environments (AREA)

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• 1986
  • 1986-12-16 DE DE19863642964 patent/DE3642964A1/de active Granted
• 1987
  • 1987-12-14 EP EP19880900359 patent/EP0301038A1/de not_active Withdrawn
  • 1987-12-14 WO PCT/EP1987/000777 patent/WO1988004755A1/en not_active Application Discontinuation
  • 1987-12-15 CA CA000554375A patent/CA1321411C/en not_active Expired - Fee Related

Patent Citations (3)

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