CA1321411C - Facade heating - Google Patents
Facade heatingInfo
- Publication number
- CA1321411C CA1321411C CA000554375A CA554375A CA1321411C CA 1321411 C CA1321411 C CA 1321411C CA 000554375 A CA000554375 A CA 000554375A CA 554375 A CA554375 A CA 554375A CA 1321411 C CA1321411 C CA 1321411C
- Authority
- CA
- Canada
- Prior art keywords
- heating
- window
- support structure
- heater
- profile
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
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]
Landscapes
- 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)
- Building Environments (AREA)
- Central Heating Systems (AREA)
- Load-Bearing And Curtain Walls (AREA)
Abstract
Abstract A metal facade construction having a heating device acting as a building heating system in a supporting struc-ture located on the inside of the building can be obtained by arranging, on the supporting structure, heating cables in grooves of the metal profiles forming the supporting struc-ture. These heating cables contain, inside an insulated enclosure, a temperature-sensitive heating conductor material which, in the event of a local temperature increase in a specific portion of the heating cable, increases its specific resistance in that portion and thereby reduces the heating capacity in order to reduce its temperature in that heating cable portion, so that the heating cable exhibits a self-regulation property over its entire length.
Description
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Facade ~Ieating The invention relates to a facade hea-ting arrangement comprising a supporting structure that can be fastened to a wall, usually an outer wall, of a building and which con-tains pro~iles, or mullions, usually oE m~tal, 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 ~ormed from double gla~ed panels. The facade heating arrangement also comprises a heating device ~or heating the supporting structure.
A metal Eacade construction of -this type is known, ~or 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 s~lpply of hot water, a building heating system is obtained that can be used for a transition or warm up period, or as an additional heating system that coopera-tes with other heating sys-tems.
It has been found that the joining together of the hot water channels which extend in the sectional cavities of the uprights and cross members makes the contruction o~ the facade heating arrangement complicated since a li~uid-impermea~le connection has to be made and maintained between the uprights and cross members and special precaution~s;have :~, :: ., . .. :
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to be taken to avoid short circuits or dead points in the heating circuit.
The heat loss through a window, even a double ~lazed window, is inherently greater than through a brick wall for example, and a relatively warm person st:anding in a room near a window with an appreciably lower outside temperature would feel some discomfort.
The present invention provides a heating arrangement and method safely to overcome or at least alleviate such heat loss and associated personal discomfort.
, ~ ccordingly, the 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 wor~ 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.
In accordance with one aspect of the present invention, there is provided 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 .....
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wherein the heater is mounted in the groove and is embedded in its raspective groove in a material having good thermal conductivity thereby to enhance thermal transfer from the heater to the profile.
In accordance with another aspect of the present invention, there is provided 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 and embedding the heater in a material having good thermal conductivity so as to effect good thermal transfer to the profile and thereby to the atmosphere adjacent the window.
Advantageously, the heater comprises a heater cable having a positive temperature coefficient (PTC) of resistivity, and comprises an elongate cable having a pair of parallel stranded metal bus bar conductors enclosed within a conductive polymeric material having a PTC characteristlc, and surrounded by an insulating jacket.
In addition to solving the problem stated above, the construction of the electrical heating device described herein makes it 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 surfaces 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.
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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 poly~er can be supplied, for example, by 220 volt alternating current~ The temperature-sensitive f~'.
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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 oE heat resistance elements connected in parallel with each other which, owing to the positive temperature coeEficient of their resistance, e~fect the selE-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 thr~ugh 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, whlch 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 eEfec-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. For example, as the hea~ing means in the heating cable, a lossy dielectric ha~ing 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 , ~ ~
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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 3ivision 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. In general, suitable heaters for use in the present invention are described for example in Raychem's U5 Patent Nos. 4188276, 4459473, and 4426339,. The heaters may be enclosed within a metal braid or foil for earthing and/or enhancing thermal transfer.
A further advantage of the self-regulating heater used in the present invention over the hot water system pre-viously used for facade heating, lies in its ability to limit the temperature to which the profiles, or mullions, of the facade support structure may be raised. This tem-perature may thus be maintained at less than about 55C, which is the temperature at which injury could be caused to a person touching the support structure.
In general, 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 ~rom 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 , !
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~ ~h, the support structure profiles, usually an aluminium or other metal extrusion, and then radiationv and/or convec-tion, from the support structure inwardly towards the air in front of the window. The dep-th of the support structure will accordingly be chosen in dependence on the surface area of the window so as to maintain a speciEied minimum tem-perature, of say 18C 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 o-ther material having good thermal conductivity.
The groove containiny the heater ~lay be closed by a cover, which may itselE be a snap-fit on or in the groove, or may be secured by clips or screws.
~ dvantageously, the groove or grooves containing the heater or heaters open into the room so that should any maintenance or replacement oE the heating system be necessary, access thereto is easily obtained without disturbing the mounting of the support structure on the wall.
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.
Embodiments of facade heating arrangements, each in accordance with the present invention, will now be described, ky way of example, with reference to ~he accom-panying drawings, in which:
Fig. 1 shows a horizontal section through the metal facade construction, in the region of a upright; it should be mentioned that the view :
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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;
FigO 2 shows a cross-section of a modification of Figure 1, wherein, in the region of a upright or cross member, additional profile grooves having additional heating cables have been provided;
Fig. 3 shows a cross-section of a further modifica-tion of Figure l;
Fig. 4 shows a cross-section of a part o a metal facaae construction in which the metal sec-tions of the supporting structure which form the uprights have been omitted, wherein that part of a proEiled 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 membe~ which is provided with grooves opening towards the inside of the buildiny for receiving heating cables;
: Fig. 5 shows a schematic equivalent circuit diagram of a heating cable portion;
Fig~ 6 shows an enlarsed view in section of a part of a upright or cross member in the region of a proEile groove containing a heating cable;
Figs 7 & 8 show enlarged views in section of modified embodiments of Figure 6;
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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 reyion 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.
In Figure l, two adjacent double glazing panels are designated l 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 S and 6 separate the framework members 3 and 4, which are clamped together, for example, by means oE screws. Details oE this arrangement have been omitted from the drawing for the sake of clarity since they are known to a person skilled in the art. On the o~side of the building, a cover 7 is clipped, using suitable locking means, on to the outer framework member 4 over the exposed fastening points.
~ he 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 of two insulatihg 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.
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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, rep~sectively, in the longitudinal direction of the hollow section 8, which heating cables fill the relevan-t groove to provide a good transfer of heat between the heatin~ cables and the hollow section 8.
For covering the groove opening, 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 oute~ surface of the hollow section ~ on the inside of the building. The flange located near the corner of the hollow section 8 is provided on the outside with a longi-tudinally extending channel in which an engaging strip of one limb of the cover strip 15 has been engaged.
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As already described, inside the groove ~2 there extends the heating cable 14 which, owing to the appropria-te 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 o~ heat to the parts of the metal section adjacent to the heating cable is brought about by thermal conduction and/or thermal radiation.
If, despite a relatively uniform removal of heat from the heating ca~le 14 to the adjacent parts of the metal profile and despite a heat distribution action as a result of the transport of heat in the longitudinal direction oE
the metal profile, the temperature in a heating cable por-tion designated L in Figure 5 rises in comparison with adjacent heating cable portions, then, owing to the self-regulating properties of the heating cables used here, there is a reduction in the current ~lowing between the parallel stranded conductors 16 and 17 as a result of the heating conductor material 18 arranged and electrically connected between the stranded conductors. This material can be regarded as a parallel connection of heat resistance ele-ments Rl~ R2, R3 ... of the equivalent circuit diagram shown in Figure 5. ~ecause of the voltage applied to -the con-ductors 16 and 17 which is substantially constant along the relatively short length of the heat.ing cable portion, this causes a reduction in the heating capacity at those heating conductor resistance elements which have heated up more, so that the temperature falls again. The heater is thus self regulating.
It should also be mentioned that 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 signiEi-cantly hindering the transport of heat.
Figures 7 and 8 show embodiments in which a sel~-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 i.ts inwardly acing side that .it i9 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. In the embodiment shown in Figure 8, 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.
In the embodiment shown in Figure 2, in addition to the grooves 11 and 12 with heating cables 13 and 14 accommodated therein, further profile grooves 24 and 25 with heating cables 26 and 27 inserted therein are provided. The grooves 24 and 25 open on the hollow section 8 in a direc-t.ion parallel to the window, it being possible to provide for these grooves and the heating cables accommodated therein a construction such as that shown in Figures 7 and 8. It will be appreciated that in the embodiment shown in Figure 2, as a modification of the construction shown, the .~ :
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- . , , grooves 11 and 12 with the flanges forming them may also be omitted, so that the hollow profile 8 presents a smooth sur-face towards the inside of the building. This form oE
construction is suitable for those uprights and cross mem-bers of a metal facade construction that are situated imme~
diately in front oE 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.
The explanation just given for the embodiment shown in Figure 2 applies correspondingly to the embodiment shown in Figure 3. The facade construction of Figure 3 differs, however, from that shown in Figure 2 in that grooves 28 and 29 for receiving heating cables 30 and 31, respectively, which open parallel to the window are not arranged near the surEace of the hollow section 8 that faces the inside of the building but are provided on the hollow profile 8, in the manner shown, in the vicinity of the thermal insulations formed by the insulation strips 9 and 10 towards the fra-mework member 3.
Finally, 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 l. Owing to the thermal insulation be~ween the inner framework member 34 and an outer framework member 35 which is obtained as a result of the elastic mounting element 5, 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.
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Figures 9 to 13 show further embodiments of grooves fitted to the metal uprights (profiles) and/or the metal cross members (profiles). These grooves, as in the exemplary embodiments described previously, are each an integral component of the relevant metal profile and are adapted to the particular cross-sectional shape of the heating cable. In the embodiments shown in Figures 9 and 10, a heating cable of circular cross-section is used, but it should be pointed out thak heating cables of rectangular or oval cross-section may also be used.
In the embodiments shown in Figures 11 and 12, 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.
Whereas in the embodimen-ts described previously, the parts of the meta~ profile or mullion containing the heating cables and the grooves are integrally connected to the upright or cross member of a framework, in the embodiment shown in Figure 1~ 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-, ~
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tively, which open at the side. The carrier 44 is Eastened, for example firmly screwed, to the hollow section 8 of a upright or cross member. The entire arrangemen-t can be covered by a cover strip 45 in the manner shownS the cover strip 45 also serving to close off the profile grooves 42 and 43. The embodiment shown in Figure 14 has the advanta~e 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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Facade ~Ieating The invention relates to a facade hea-ting arrangement comprising a supporting structure that can be fastened to a wall, usually an outer wall, of a building and which con-tains pro~iles, or mullions, usually oE m~tal, 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 ~ormed from double gla~ed panels. The facade heating arrangement also comprises a heating device ~or heating the supporting structure.
A metal Eacade construction of -this type is known, ~or 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 s~lpply of hot water, a building heating system is obtained that can be used for a transition or warm up period, or as an additional heating system that coopera-tes with other heating sys-tems.
It has been found that the joining together of the hot water channels which extend in the sectional cavities of the uprights and cross members makes the contruction o~ the facade heating arrangement complicated since a li~uid-impermea~le connection has to be made and maintained between the uprights and cross members and special precaution~s;have :~, :: ., . .. :
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to be taken to avoid short circuits or dead points in the heating circuit.
The heat loss through a window, even a double ~lazed window, is inherently greater than through a brick wall for example, and a relatively warm person st:anding in a room near a window with an appreciably lower outside temperature would feel some discomfort.
The present invention provides a heating arrangement and method safely to overcome or at least alleviate such heat loss and associated personal discomfort.
, ~ ccordingly, the 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 wor~ 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.
In accordance with one aspect of the present invention, there is provided 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 .....
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wherein the heater is mounted in the groove and is embedded in its raspective groove in a material having good thermal conductivity thereby to enhance thermal transfer from the heater to the profile.
In accordance with another aspect of the present invention, there is provided 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 and embedding the heater in a material having good thermal conductivity so as to effect good thermal transfer to the profile and thereby to the atmosphere adjacent the window.
Advantageously, the heater comprises a heater cable having a positive temperature coefficient (PTC) of resistivity, and comprises an elongate cable having a pair of parallel stranded metal bus bar conductors enclosed within a conductive polymeric material having a PTC characteristlc, and surrounded by an insulating jacket.
In addition to solving the problem stated above, the construction of the electrical heating device described herein makes it 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 surfaces 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.
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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 poly~er can be supplied, for example, by 220 volt alternating current~ The temperature-sensitive f~'.
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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 oE heat resistance elements connected in parallel with each other which, owing to the positive temperature coeEficient of their resistance, e~fect the selE-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 thr~ugh 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, whlch 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 eEfec-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. For example, as the hea~ing means in the heating cable, a lossy dielectric ha~ing 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 , ~ ~
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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 3ivision 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. In general, suitable heaters for use in the present invention are described for example in Raychem's U5 Patent Nos. 4188276, 4459473, and 4426339,. The heaters may be enclosed within a metal braid or foil for earthing and/or enhancing thermal transfer.
A further advantage of the self-regulating heater used in the present invention over the hot water system pre-viously used for facade heating, lies in its ability to limit the temperature to which the profiles, or mullions, of the facade support structure may be raised. This tem-perature may thus be maintained at less than about 55C, which is the temperature at which injury could be caused to a person touching the support structure.
In general, 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 ~rom 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 , !
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, ` ;"
.
~ ~h, the support structure profiles, usually an aluminium or other metal extrusion, and then radiationv and/or convec-tion, from the support structure inwardly towards the air in front of the window. The dep-th of the support structure will accordingly be chosen in dependence on the surface area of the window so as to maintain a speciEied minimum tem-perature, of say 18C 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 o-ther material having good thermal conductivity.
The groove containiny the heater ~lay be closed by a cover, which may itselE be a snap-fit on or in the groove, or may be secured by clips or screws.
~ dvantageously, the groove or grooves containing the heater or heaters open into the room so that should any maintenance or replacement oE the heating system be necessary, access thereto is easily obtained without disturbing the mounting of the support structure on the wall.
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.
Embodiments of facade heating arrangements, each in accordance with the present invention, will now be described, ky way of example, with reference to ~he accom-panying drawings, in which:
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;
FigO 2 shows a cross-section of a modification of Figure 1, wherein, in the region of a upright or cross member, additional profile grooves having additional heating cables have been provided;
Fig. 3 shows a cross-section of a further modifica-tion of Figure l;
Fig. 4 shows a cross-section of a part o a metal facaae construction in which the metal sec-tions of the supporting structure which form the uprights have been omitted, wherein that part of a proEiled 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 membe~ which is provided with grooves opening towards the inside of the buildiny for receiving heating cables;
: Fig. 5 shows a schematic equivalent circuit diagram of a heating cable portion;
Fig~ 6 shows an enlarsed view in section of a part of a upright or cross member in the region of a proEile groove containing a heating cable;
Figs 7 & 8 show enlarged views in section of modified embodiments of Figure 6;
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.' '. :','.
,, ~
' !
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 reyion 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.
In Figure l, two adjacent double glazing panels are designated l 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 S and 6 separate the framework members 3 and 4, which are clamped together, for example, by means oE screws. Details oE this arrangement have been omitted from the drawing for the sake of clarity since they are known to a person skilled in the art. On the o~side of the building, a cover 7 is clipped, using suitable locking means, on to the outer framework member 4 over the exposed fastening points.
~ he 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 of two insulatihg 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.
., ., ~, i . ., : ` ' :
'' ~
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, rep~sectively, in the longitudinal direction of the hollow section 8, which heating cables fill the relevan-t groove to provide a good transfer of heat between the heatin~ cables and the hollow section 8.
For covering the groove opening, 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 oute~ surface of the hollow section ~ on the inside of the building. The flange located near the corner of the hollow section 8 is provided on the outside with a longi-tudinally extending channel in which an engaging strip of one limb of the cover strip 15 has been engaged.
..
., : :
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:: . . .....
~ '~ r~
As already described, inside the groove ~2 there extends the heating cable 14 which, owing to the appropria-te 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 o~ heat to the parts of the metal section adjacent to the heating cable is brought about by thermal conduction and/or thermal radiation.
If, despite a relatively uniform removal of heat from the heating ca~le 14 to the adjacent parts of the metal profile and despite a heat distribution action as a result of the transport of heat in the longitudinal direction oE
the metal profile, the temperature in a heating cable por-tion designated L in Figure 5 rises in comparison with adjacent heating cable portions, then, owing to the self-regulating properties of the heating cables used here, there is a reduction in the current ~lowing between the parallel stranded conductors 16 and 17 as a result of the heating conductor material 18 arranged and electrically connected between the stranded conductors. This material can be regarded as a parallel connection of heat resistance ele-ments Rl~ R2, R3 ... of the equivalent circuit diagram shown in Figure 5. ~ecause of the voltage applied to -the con-ductors 16 and 17 which is substantially constant along the relatively short length of the heat.ing cable portion, this causes a reduction in the heating capacity at those heating conductor resistance elements which have heated up more, so that the temperature falls again. The heater is thus self regulating.
It should also be mentioned that 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 signiEi-cantly hindering the transport of heat.
Figures 7 and 8 show embodiments in which a sel~-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 i.ts inwardly acing side that .it i9 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. In the embodiment shown in Figure 8, 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.
In the embodiment shown in Figure 2, in addition to the grooves 11 and 12 with heating cables 13 and 14 accommodated therein, further profile grooves 24 and 25 with heating cables 26 and 27 inserted therein are provided. The grooves 24 and 25 open on the hollow section 8 in a direc-t.ion parallel to the window, it being possible to provide for these grooves and the heating cables accommodated therein a construction such as that shown in Figures 7 and 8. It will be appreciated that in the embodiment shown in Figure 2, as a modification of the construction shown, the .~ :
~ . ~
.
- . , , grooves 11 and 12 with the flanges forming them may also be omitted, so that the hollow profile 8 presents a smooth sur-face towards the inside of the building. This form oE
construction is suitable for those uprights and cross mem-bers of a metal facade construction that are situated imme~
diately in front oE 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.
The explanation just given for the embodiment shown in Figure 2 applies correspondingly to the embodiment shown in Figure 3. The facade construction of Figure 3 differs, however, from that shown in Figure 2 in that grooves 28 and 29 for receiving heating cables 30 and 31, respectively, which open parallel to the window are not arranged near the surEace of the hollow section 8 that faces the inside of the building but are provided on the hollow profile 8, in the manner shown, in the vicinity of the thermal insulations formed by the insulation strips 9 and 10 towards the fra-mework member 3.
Finally, 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 l. Owing to the thermal insulation be~ween the inner framework member 34 and an outer framework member 35 which is obtained as a result of the elastic mounting element 5, 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.
~, ~, , .
- 13 - G06l CA
Figures 9 to 13 show further embodiments of grooves fitted to the metal uprights (profiles) and/or the metal cross members (profiles). These grooves, as in the exemplary embodiments described previously, are each an integral component of the relevant metal profile and are adapted to the particular cross-sectional shape of the heating cable. In the embodiments shown in Figures 9 and 10, a heating cable of circular cross-section is used, but it should be pointed out thak heating cables of rectangular or oval cross-section may also be used.
In the embodiments shown in Figures 11 and 12, 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.
Whereas in the embodimen-ts described previously, the parts of the meta~ profile or mullion containing the heating cables and the grooves are integrally connected to the upright or cross member of a framework, in the embodiment shown in Figure 1~ 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 Eastened, for example firmly screwed, to the hollow section 8 of a upright or cross member. The entire arrangemen-t can be covered by a cover strip 45 in the manner shownS the cover strip 45 also serving to close off the profile grooves 42 and 43. The embodiment shown in Figure 14 has the advanta~e 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.
.
~; , ' ' ' :
:
: .
Claims (8)
1. 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 (1) the thermally conductive support structure comprises an elongate profile having a groove therein, (2) the heating means comprises at least one elongate electrical heater that has a positive temperature coefficient of resistance, and (3) the or each heater is mounted in the groove and is embedded in its respective groove in a material having good thermal conductivity thereby to enhance thermal transfer from the heater to the profile.
2. An arrangement according to claim 1, wherein the thermally conductive support structure comprises one or more of said profiles arranged in a substantially closed configuration, so as in use substantially completely to surround the window, and wherein one or more of said heaters extends in grooves along said profile configuration.
3. An arrangement according to claim 1, wherein the or each heater is mounted as a snap-fit into its respective groove.
4. An arrangement according to claim 1, 2 or 3, wherein the or each groove has a cover secured thereto, thereby to enhance thermal transfer from the enclosed heater to its associated profile.
5. An arrangement according to claim 1, 2 or 3, wherein the thermally conductive support structure comprises one or more elongate metal extrusions.
6. An arrangement according to claim 1, 2 or 3, comprising thermal insulation means disposed between the arrangement and the wall, thereby to hinder thermal conduction from the arrangement to the window.
7. A method of heating the atmosphere inside a building adjacent a window in a wall thereof, said method comprising (1) mounting a thermally conductive support structure on the inside of said wall adjacent the window so as to extend away therefrom, and (2) mounting an elongate heater having a positive temperature coefficient of resistance in a groove of an elongate profile of the support structure and embedding the heater in a material having good thermal conductivity so as to effect good thermal transfer to the profile and thereby to the atmosphere adjacent the window.
8. A method according to claim 7, wherein the support structure is mounted on the wall so as substantially completely to surround the window.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3642964.3 | 1986-12-16 | ||
| DE19863642964 DE3642964A1 (en) | 1986-12-16 | 1986-12-16 | METAL FACADE CONSTRUCTION |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1321411C true CA1321411C (en) | 1993-08-17 |
Family
ID=6316312
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000554375A Expired - Fee Related CA1321411C (en) | 1986-12-16 | 1987-12-15 | Facade heating |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0301038A1 (en) |
| CA (1) | CA1321411C (en) |
| DE (1) | DE3642964A1 (en) |
| WO (1) | WO1988004755A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4029245C3 (en) * | 1990-09-14 | 1998-08-13 | Gartner & Co J | Arrangement of guide elements for electrical cables in the facade area of buildings |
| EP0550841B1 (en) * | 1991-12-09 | 1997-09-03 | WICONA BAUSYSTEME GMBH & CO. KG | Curtain wall |
| CA2594497A1 (en) * | 2005-01-14 | 2006-07-20 | Schueco International Kg | Section for a window or facade and electric cable for a section for a window, door or facade |
| DE202005000582U1 (en) * | 2005-01-14 | 2006-05-24 | Schüco International KG. | Cable for frame section for surrounding frame or leaf frame or section for window, door or facade has two or more conductors whereby cable is designed as ribbon cable which has lateral projections at its narrow side |
| DE202005000580U1 (en) * | 2005-01-14 | 2006-05-24 | SCHÜCO International KG | Frame section for blind frame or sash of e.g. window, has undercut cable groove arranged at outer periphery of section for retaining electrical cable in form-fit manner, and centering frame fastened at section and attached to cable |
| DE202005000608U1 (en) * | 2005-01-14 | 2006-05-24 | SCHÜCO International KG | Cable for frame section for surrounding frame or leaf frame or section for window, door or facade has two or more conductors whereby cable is designed as ribbon cable which has lateral projections at its narrow side |
| BE1026971B1 (en) * | 2019-01-15 | 2020-08-17 | Claeys Stephanie Catharina R | Curtain wall and method of mounting it |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NO120699B (en) * | 1967-10-20 | 1970-11-23 | Svenska Flaektfabriken Ab | |
| GB2052228B (en) * | 1979-05-10 | 1983-04-07 | Sunbeam Corp | Flexible heating elements and dies and processes for the production thereof |
| DE2942523C2 (en) * | 1979-10-20 | 1981-11-19 | Türk & Hillinger GmbH & Co, 7200 Tuttlingen | Electric water heater |
| JPS5927047A (en) * | 1982-08-03 | 1984-02-13 | ワイケイケイ株式会社 | Panel support part of curtain wall |
| EP0116985A3 (en) * | 1983-02-15 | 1985-08-07 | Jean Michel Anthony | Device for preventing the formation of condensation on door or window frames |
-
1986
- 1986-12-16 DE DE19863642964 patent/DE3642964A1/en active Granted
-
1987
- 1987-12-14 EP EP19880900359 patent/EP0301038A1/en 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
Also Published As
| Publication number | Publication date |
|---|---|
| DE3642964C2 (en) | 1991-10-10 |
| EP0301038A1 (en) | 1989-02-01 |
| WO1988004755A1 (en) | 1988-06-30 |
| DE3642964A1 (en) | 1988-07-28 |
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| Date | Code | Title | Description |
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| MKLA | Lapsed |