GB1568663A - Solar heating installations - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO SOLAR HEATING INSTALLATIONS (71) We, CONCORDIA DEVELOPMENT AB, a Swedish Company, of Ingenjorscen- trum, 191 78 Sollentuna, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: The present invention relates to a method of heating by solar energy buildings having an outer roof and/or wall structure which comprises or comprise plate-like heat-absorbing and heat transmitting building elemeats such as roofing tiles, arranged adjacent each other and which elements are supported via spacers on a heat-insulating support surface such as to form an air duct between said building elements and said support surface. Heat transmitted by said building elements is conducted away by means of a heat-absorbing medium flowing in said air gap.

The invention also relates to a building having an outer roof and/or wall structure comprising plate-like building elements which are arranged adjacent each other and which are supported through spacers on a hcat-insulating support surface such as to form an air duct between said elements and said surfaces.

It is known to place in an opening in the outer roof structure of a building, a sheet of material which is permeable to solar heat radiation and which forms a wall section of a closed channel system extending along said roof structure. Beneath this wall section there is arranged in the channel a solar-heat absorbing body which, when heated by the sun's rays incident, thereon, heats air flowing in the channel, which air, in turn, transmits heat to a space located within the - building and forming part of the channel system, in which space a stove for storing heat is accommodated.

This known arrangement is much simpler than previous arrangements intended for - satt- purp*se. Ofle senous-disadvan; tage, however, is the difficulty of providing the channel with a heat-absorbing body in the roof and of sealing the permeable sheet against the ingress or egress of water and air. Another disadvantage resides in the fact that the heated air flows in the space between the permeable sheet and the heatabsorbing body, rendering it impossible td avoid considerable heat losses. Neither can existing buildings be modified in this way, since it would require radical changes to the construction of both the roof and the walls of the building. Moreover, in the majority of cases the heat-accumulating store can only be positioned beneath a building in conjunction with its- construction.

An object of the present invention is to provide an improved and simpler solar heating installation which can be readily installed in existing buildings.

According to one aspect this invention consists in a method of heating by solar energy a building having an outer roof and/ or wall structure which comprises plate-like heat-absorbing and heat-transmitting building elements arranged adjacent each other and supported through spacers on a heatinsulating support surface such as to form an air duct between said elements and said heat-insulating support surface, said method comprising covering at least one of said building elements with a spaced covering of heat-insulation material permeable to solar radiation; securing said covering in a manner such as to form a substantially closed space between the covered building element or elements and said covering; causing air heated in said duct beneath the covered element or elements by heat exchange with said elements to move along said duct; and introducing said air into the interior of said building.

According to another aspect this invention consists of a building having an outer roof and/or wall structure comprising plate.

like heat absorbing and- heat transmitting building elements which are arranged adjacent each other and which are supported through spacers on a heat insulating support surface; such as ta form an ir duct between said elements and- said surface, wherein at least one of said building elements is covered on the outer surfaces thereof with a-spaced covering of heat- insulating material permeable to solar radiation, said covering being secured in such manner as to form a substantially closed space between the covered building element or elements and said covering, wherein means are provided for causing air heated in said duct beneath the covered building element or elements to move along said duct, and wherein said duct is arranged to communicate- - with- openings for removing air from and introducing air into the in terior -of- said building.

The -invention affords the advantage whereby the outer roof structure and/or wall structure of an existing building can be utilized for absorbing heat and for storing it. - In the case of roofing tiles made of brick or concrete, for example, the heataccumulating'mass constitutes not less than 30-40 kg/m2 of roof. Similarly, an existing air gap or air gaps between the building elements and the support surface can be used without modification or, if necessary, may be modified to convey heat, instead-of it being necessary to provide. especi;ally arranged, closed channels, as is the case with the aforedescribed known installations.It is also possible, by way of an alternative, subsequently to mount pipes for- conveying a heat-carrying liquid in the gap -or gaps, if so desired. -A particularly - high degree of efficiency can - be obtained, owing to the fact that a small stream of air, which is rapidly heated-onothe outer surface of--a building element, can be passed over to the inner face- of the. building -elements located thereabove, thereby. greatly reducing heat losses and reducing the surface temperature of the outer surfaces of the- building elemelts.

In order to effectively seal the building elements and to secure them reliably to the underlying support surface, one or more layers of a-thin, strong and pliant foil- material permeable to solar radiation -may be -arranged over -a group of building elements, between said- elements and their respective covers, the foil extending along mutually opposing edges -of the rows of building elements preferably exhibits folds which extend down to the underlying support surface and attached thereto.

With-a foil--maten.a-l--thus- - arranged, the layer or layers thereof provide an effective seal and enclose insulating air layers which prevent heat emitted by the tiles from radiating outwards, while present ing no serious obstacle to heating of the tiles by solar radiation, thereby - consider ably reducing heat losseS: A weakness with silch- an; arrangement, however, is that its ability to store heat is limited to the number of building elements.

A considerable improvement in this respect would be if it were possible; to increase the storage capacity of: the arrangement in re spect of a given number of building ele ments to two or three days. Such an in crease can be obtained by hermetically enclosing in aluminium foil a solid heat accumulating substance of suitably low melting point, such as Glauber salt, and placing it between the insulating support surface and the undersurface of the building ele ments. Supplementary hereto, a layer of solar cells, e.g. solar cells containing sili con, may be arranged adjacent the outer surface of the building elements for ex ample on the inside of a cover provided with clamping means for attaching it to an associated building element and made of a material which permits solar radiation to pass therethrough.

For the purpose of forming an air cushion between the foil and the outer face of the building elements, means, such as resilient support structures, can be provided to hold the pliant foil close to the undersurface of respective covers. In this respect, it is con venient to provide the foil with perfora tions which permit a restricted flow of am bient air through the spaces formed under the foil to the spaces between overlapping portions of the building elements and further to the undersurfaces of the -elements located thereabove.

Exemplary embodiments of the inven tion will now be - described- in more detail with reference to the accompanying sche matic -drawings, in which: Figure 1 is a cross-sectional view of a building provided with an installation ac cording to one embodiment of the inven tion in both the outer roof structure and an outside wall;.

Figure 2 is a sectional view of roofing tiles covered with individual covers; Figure 3 is -a perspective view in section of a particularly simple, preforred arrange ment according to the invention for use on the roof of buildings; Figure 4 is a - loflgftudinal-- sectional view through a; further embodiment - of the- in yention; Figure 5 is a cross-sectio-nal view--of - ar rangement according to the invention - in- tended.for-use. on the wall of a building: Figure 6 is a sectional view perpendicu- lar ot the direction in which the roof slopes and illustrates a preferred embodiment of an arrangement according to the invention; Figure 7 is a sectional view parallel with the direction in which the roof slopes and illustrating the same arrangement; and Figure 8 shows a horizontal sealing strip.

The wall 1 and the roof section 2 of the building shown in Figure 1 are presumed to have a predominantly southenly aspect.

The outside wall is covered with known building elements 3 hung on the wall in the same manner as conventional building tiles. Between the outside - wall and -an inside wall 5 there is an air gap or duct 4.

Arranged at the bottom and at the top of the inner wall 5 are openings 6 and 7 re spectively, through which the air gap or duct 4 communicates with the interior of the building. The roof of the building is covered in a conventional manner with roofing tiles 10 which may be made of brick or concrete and which are fastened to respective battens 11 in a manner to form an air gap 12 between said tiles and an underlying roofing structure 13 of wood.

The air gap 12 communicates with the interior of the building through a lower opening 14 and an upper opening 15. Each of the upper openings 7 and 15 co-operate with a respective small fan 16 each of which, together with valves arranged in some suitable position in the building, is eontrolled by control means -(not shown) in a manner known per se: The outer surfaces of the wallelements 3 and the roofing tiles 10 are provided with a cover comprising a heat-insulating ma terial permeable to solar radiation and in tended to enhance heating of the roofing tiles and the wall elements when these are subjected to solar radiation.In principle, it is possible to cover the whole of the wall and/-or-- the' whole- of the surface- of the roof with a thick, coherent covering, of, for example porous, transparent plas tics material. In particular darkly coloured wall elements and roofing tiles thus covered will -be. heated to relatively high temperatures when subjected to-strong sunlight, this heat penetrating through said wall elements and tiles to -heat -the - air flowing in the air gaps 4 and 12. As will readily be perceived, it would be both diffi cult and expensive to provide such a cover ing in the form of a single continuous covering, besides being difficult to main tain it in a serviceable condition.The main difficulty, however, would be in secur ing the covering in a manner to prevent it from being torn loose by strong winds, for example. Instead of a single continuous covering however, conveniently each wall element 3 and roofing tile 10--may- 'oe t?ro vided with an individual cover 20 and 21 made ;-of.--a suitable plastics material each cover being placed over the outer surface b@its respective wall element and tile so as tosbe spaced thereform, wherewith between the dover and the wall element 3 or roofing tile I lû there is formed a heat-insulating air layer 22.

An example of roofing tiles 10 faced with covers 21 is shown in Figures 2 and 3. These covers are provided with spring clamping elements in the form of tongues 23 (Figure 3) arranged to grip around the side edges of respective tiles, thereby enabl- ing the covers to be readily placed over.

respective tiles of an existing building. The space accommodating the insulating air la;'yer - 22' may be defined by projections 24 or like spacers extending between a cover 21 and its respective tile 10.

Air is caused to flow through the gap 12 by its associated fan 16, hot air will also flow along the gap owing to its - tendency to rise. A certain amount of cold, fresh, air will enter through spacers between the tiles and mix with the warm air, although the extent to which this can happen is greatly reduced by the fact that the thin- walled material of the covers 21 is effective substantially to seal these interspaces. It is necessary, however, to provide a separate seal 25 made, for example, from foam plastics, beneath the undermost row of roofing tiles to seal against the ingress of ambient air. Suitably, the seal 25 is provided with variable through-flow openings so that the amount of air entering beneath the lowermost row of roofing tiles can be modified according to the prevailing climate.Arranged adjacent the lower edges of the roofing tiles. 10 when in use is a downwardly folded edge 26 of cover 21, which edge serves as a seal or a baffle. A certain inflow of ambient air into the space 22 is desirable when temperatures are particularly high. To this end, a row of bags27 filled with air can be arranged at rela- tively long distances apart along the edges 26 between the lower edge surface of a tile 10 and the opposing surfaces of a respective seal 26, this arrangement. being such that a gap is opened between said seal 26 and said surface when air in the bags expands as ,a result of a steep rise in temperature. 'One particular advantage afforded by such an air stream resides in the fact that the relatively well heated air in the space 22 will automatically leak into the underside of the overlying roofing tile, and in so doing will prevent the upper sides of the roofing tiles from being heated to high surface temperatures, thereby enhancing the efficiency. of the process.

As shown in Figure 4, a metal foil 30 may be attached to the cover 21 so as to hermetically seat the space 22. The metal foil 30 is suitably corrugated or folded to increase the specific area of the heat-absorbing surface, which is suitably a darkcoloured suffice, and to ådapt the surface of the foil to the angle of incidence of solar radiation to favourable values, which is particularly suitable in the case of the covers on the wall elements. Air will flow in the intermediate space 22 over the roofing tiles in the same manner as that described above.

Figure 5 is a view of a wall element 3 provided with a cover 20. In this embodiment, liquid-carrying hoses or pipes 32 may be arranged in respective air gaps 4 and 12, whereby the liquid flowing in the hoses, is heated by the heat emitted by the air flowing in the gaps, the heat from said liquid being transmitted to a heat store 40 (Figure 1) beneath the building or being used to preheat water in a heat-exchanger or water-heater (not shown); although the hoses are shown arranged beneath the building elements 3, it will be understood that such hoses may also be arranged beneath the roofing tiles, for the same purpose.An important advantage afforded by the arrangement according to the invention is, however, that the need for a heat store for short-time accumulation of heat is small, since the heat-accumulating capacity of the roofing tiles 10 and the wall elements 3 is quite considerable. Another important feature of the arrangement according to the invention is that it can readily be installed in existing buildings with practically no need for modification thereto, the one exception being the need to provide the openings 6, 7 and/or 14, 15 therein although it will be understood that tiles 10 must be lifted and replaced; prevoiusly known methods for heating flowing air have, in practice, only been applicable in new constructions.The roofing tiles l0 and, when found, wall elements 13 of said existing building are preferably darkened and "impregnated" with a metal powder containing a pigment for increasing the heat absorption characteristics thereof and for improving heat transmission through the roofing tiles and wall elements.

In the drawings, Figures 68, there is shown a roof 41 having rafters 42, a sup port structure 43 and roofing tiles 44 arranged in a conventional manner. Between the rafters 43 there is arranged a covering of insulating material 45 on which aluminium-foil bags 46 containing Glauber salt are disposed. Extending over each roofing tile are two resilient support structures 53 supporting a sheet 47-of pliant material which is permeable to solar radiation and which is preferably a material sold under the registered Trade- Mark TEDLAR by Du Pont and having a thick ness of- approximately 25 microns. Covers 4 cover the sheet 47.

The sheet 47 and the covers 48 are arranged in the following manner. A strip of foil is extended, if possible, from the ridge-pole area of the roof structure down to the eaves thereof, or along a selected group of roofing tiles, and is nailed along the edge of a row of tiles to the rafters 42 or through the insulating layer to the roof, and thereafter placed over the support structures 53 attached to the roofing tiles in the row and nailed in the described manner to the supporting surface on the other side of said row. A cover 48 is then clamped to each roofing tile in the row.

The strip 47 of material is then folded back slightly, whilst the next row of tiles are layed in position and the strip is folded over the stirrup-structures 53 attached to the new row of tiles and nailed fast in the aforedescribed manner along the remote edge of the new row of tiles, etc.

As shown in Figure 7, the strip of material extends in step fashion down the rows of roofing tiles. Adjacent the lower edge of each roofing tile, the strip may be provided with a number of small openings 50 beneath the lower edge of an associated cover 48. In this way ambient air can flow in limited quantities through the openings 50 and the space beneath the strip 47 and in beneath the undersurface of the overlying roofing tiles.

To prevent ambient air from flowing in beneath the roofing tiles, a seal must be arranged around the group of roofing tiles arranged to capture solar energy. Such sealing means may comprise vertical strips 51 of foamed plastics having a planar upper surface and horizontal strips 52 having an upper surface which is arcuate so as to conform with the arcuate shape of the roofing tiles.

The building elements which in the illú- strated embodiment have been designated roofing tiles, may comprise, for example, cement tiles or an iron plate of appropriate configuration.

WHAT WE CLAIM IS: 1. A method of heating by solar energy a building having an outer roof and/or wall structure which comprises plate-like heat-absorbing and heat-transmitting building elements arranged adjacent each other and supported through spacers on a heatinsulating support surface such as to form an air duct between said elements and said heat-insulating support surface, said method comprising covering at least one of said building elements with a sPaced covering of a heat-insulating material pel- meable to solar radiation; securing said covering in a manner such 'as to form å substantially closed space between the covered-building element or elements and said. covering; causing air-heåttd in-said

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (1)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   of the foil to the angle of incidence of solar radiation to favourable values, which is particularly suitable in the case of the covers on the wall elements. Air will flow in the intermediate space 22 over the roofing tiles in the same manner as that described above.

   Figure 5 is a view of a wall element 3 provided with a cover 20. In this embodiment, liquid-carrying hoses or pipes 32 may be arranged in respective air gaps 4 and 12, whereby the liquid flowing in the hoses, is heated by the heat emitted by the air flowing in the gaps, the heat from said liquid being transmitted to a heat store 40 (Figure 1) beneath the building or being used to preheat water in a heat-exchanger or water-heater (not shown); although the hoses are shown arranged beneath the building elements 3, it will be understood that such hoses may also be arranged beneath the roofing tiles, for the same purpose.An important advantage afforded by the arrangement according to the invention is, however, that the need for a heat store for short-time accumulation of heat is small, since the heat-accumulating capacity of the roofing tiles 10 and the wall elements 3 is quite considerable. Another important feature of the arrangement according to the invention is that it can readily be installed in existing buildings with practically no need for modification thereto, the one exception being the need to provide the openings 6, 7 and/or 14, 15 therein although it will be understood that tiles 10 must be lifted and replaced; prevoiusly known methods for heating flowing air have, in practice, only been applicable in new constructions.The roofing tiles l0 and, when found, wall elements 13 of said existing building are preferably darkened and "impregnated" with a metal powder containing a pigment for increasing the heat absorption characteristics thereof and for improving heat transmission through the roofing tiles and wall elements.

   In the drawings, Figures 68, there is shown a roof 41 having rafters 42, a sup port structure 43 and roofing tiles 44 arranged in a conventional manner. Between the rafters 43 there is arranged a covering of insulating material 45 on which aluminium-foil bags 46 containing Glauber salt are disposed. Extending over each roofing tile are two resilient support structures 53 supporting a sheet 47-of pliant material which is permeable to solar radiation and which is preferably a material sold under the registered Trade- Mark TEDLAR by Du Pont and having a thick ness of- approximately 25 microns. Covers 4 cover the sheet 47.

   The sheet 47 and the covers 48 are arranged in the following manner. A strip of foil is extended, if possible, from the ridge-pole area of the roof structure down to the eaves thereof, or along a selected group of roofing tiles, and is nailed along the edge of a row of tiles to the rafters 42 or through the insulating layer to the roof, and thereafter placed over the support structures 53 attached to the roofing tiles in the row and nailed in the described manner to the supporting surface on the other side of said row. A cover 48 is then clamped to each roofing tile in the row.

   The strip 47 of material is then folded back slightly, whilst the next row of tiles are layed in position and the strip is folded over the stirrup-structures 53 attached to the new row of tiles and nailed fast in the aforedescribed manner along the remote edge of the new row of tiles, etc.

   As shown in Figure 7, the strip of material extends in step fashion down the rows of roofing tiles. Adjacent the lower edge of each roofing tile, the strip may be provided with a number of small openings 50 beneath the lower edge of an associated cover 48. In this way ambient air can flow in limited quantities through the openings 50 and the space beneath the strip 47 and in beneath the undersurface of the overlying roofing tiles.

   To prevent ambient air from flowing in beneath the roofing tiles, a seal must be arranged around the group of roofing tiles arranged to capture solar energy. Such sealing means may comprise vertical strips 51 of foamed plastics having a planar upper surface and horizontal strips 52 having an upper surface which is arcuate so as to conform with the arcuate shape of the roofing tiles.

   The building elements which in the illú- strated embodiment have been designated roofing tiles, may comprise, for example, cement tiles or an iron plate of appropriate configuration.

   WHAT WE CLAIM IS:

   1. A method of heating by solar energy a building having an outer roof and/or wall structure which comprises plate-like heat-absorbing and heat-transmitting building elements arranged adjacent each other and supported through spacers on a heatinsulating support surface such as to form an air duct between said elements and said heat-insulating support surface, said method comprising covering at least one of said building elements with a sPaced covering of a heat-insulating material pel- meable to solar radiation; securing said covering in a manner such 'as to form å substantially closed space between the covered-building element or elements and said. covering; causing air-heåttd in-said

   duct beneath the covered element or elements by heat exchange therewith to move along said duct, and introducing said air into the interior of said building.

   2. A building having an outer roof and/or wall structure comprising plate-like heat-absorbing and heat-transmitting building elements which are arranged adjacent each other and which are supported through spacers on a heat-insulating support surface such as to form an air duct between said elements and said surface, wherein at least one of said elements is covered on the outer surfaces thereof with a spaced covering of heat-insulating material permeable to solar radiation, said covering being secured in such manner as to form a substantially closed space between the covered building element or elements and said covering, wherein means are provided for causing air in said duct beneath the covered building element or elements to move along said duct; and wherein said duct is arranged to communicate with openings for withdrawing air from and introducing said air into the interior of said building.

   3. A building according to Claim 2, wherein the side of said cover facing the building element or elements is a heatradiation absorbing foil, which together with the cover forms a hermetically sealed chamber.

   4. A building according to Claim 3, wherein the foil is a darkly-coloured metal foil.

   5. A building according to any one of Claims 24 wherein the building elements are tiles having overlapping upper and lower edges, and wherein means are provided which enable the flow of air from the outer side of one tile to the inner sur face of a further tile lying thereupon through the space formed between the overlapping edges of said tiles.

   6. A building according to Claim 2, wherein at least one further covering of a strong and pliant foil material permeable to sdar radiation is arranged to extend over the covered building element or elements between said elements and the first mentioned cover, said foil exhibiting folds which extend along the mutually opposing edges of the rows of building elements down towards said underlying support surface and fixed thereto.

   7. A building according to any of Claims 2-6, wherein a layer of solid, heataccumulating material having a suitably low melting point, herinetically enclosed in the absence of air between aluminium foil is arranged on the insulating underlying support surface.

   8. A building according to Claim 6, wherein a layer of solar cells, is arranged beneath the covers,

   9. A building according to Claim 8, wherein said cells are silicon solar cells.

   10. A building according to Claim 6 characterised in that means, such as resilient support structures, are arranged to hold the pliant foil raised towards the undersurfaces of the covers.

   11. A building according to Claim 6 or any one of Claims 7 to 9 dependent thereon, wherein the further pliant cover is provided with perforations which permit a limited flow of ambient air through the spaces formed beneath said further cover to the spaces between the overlapping portions of the building elements.

   12. A building according to any one of Claims 2-li, wherein around a group of building elements there is arranged a sealing wall between the undersurfaces of the building elements and the insulating underlying support surface.

   14. A building having an outer roof and/or wall structure substantially as herein-before described with reference to, and as illustrated in, the accompanying drawings.