GB2461797A

GB2461797A - Heat exchange plate for roofing and other building applications

Info

Publication number: GB2461797A
Application number: GB0911896A
Authority: GB
Inventors: Richard Antony Morton Maskell
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-07-12
Filing date: 2009-07-09
Publication date: 2010-01-20
Also published as: GB0812810D0; GB0911896D0

Abstract

A heat exchange plate which can be installed beneath a roofing tile includes a generally planar heat collector 17 formed of a heat-conducting material with a fluid conduit 20 in thermal contact with a rear face of the heat collector. The heat collector 17 has a top margin which is affixed to a roofing batten 12.1 through holes 19, with one or more downward projections which locate over the batten. A bottom margin of the heat collector is supported on a further roofing batten 12.2. Access holes 22 and 23 are provided for couplers 24 by which the conduits 20 are joined together. The heat exchange plate may be incorporated into a climate control system of a building, which incorporates a heat pump for transferring heat from a roof structure into a climate control heat exchanger, e.g. underfloor heating.

Description

HEAT EXCHANGE PLATE FOR ROOFING

AND OTHER BUILDING APPLICATIONS

TECHNICAL FIELD OF THE INVENTION

This invention relates to a heat exchange plate which is suitable for use in roofing and other building applications.

BACKGROUND

Governments are encouraging people to improve the energy efficiency of their buildings, and the use of roof-mounted solar panels to heat water is now commonplace. Nevertheless, such solar panels are not always acceptable since they detract from the visual appearance of a building, and their use may even be prohibited on listed buildings for example.

Solar roofing tiles have been proposed which incorporate a fluid circulation conduit, but although they are capable of high efficiency they are not always capable of being installed on existing roofs. Furthermore, they do not blend in well with any existing tiles, and their use may still be prohibited in some areas.

The present invention seeks to provide a new and inventive way of easily adapting a new or existing roof for fluid circulation which is capable of good heat-transfer efficiency without affecting the external appearance of the roof.

SUMMARY OF THE INVENTION

The present invention proposes a heat exchange plate for use in a heating or cooling system for installation in a building, the plate including a generally planar heat collector formed of a heat-conducting material having a rear face with top and bottom margins which can be supported against spaced battens in use, an upper edge of the heat collector at said top margin having one or more rearward projections to locate over the respective batten, and in which a fluid conduit is applied to a rear face of the heat collector in thermal contact therewith between the top and bottom margins.

The interconnection of adjacent heat exchange plates may be facilitated by providing the heat collector with at least one access hole which accommodates an end of the fluid conduit. Preferably the access holes are arranged such that when two of the plates are mounted side-by-side the access holes are conjoined.

The heat exchange plate may be incorporated into a climate control system of a building, which incorporates a heat pump for transferring heat from a roof structure to a climate control heat exchanger. The heat pump is preferably reversible, e.g. by changing the direction of flow around a vapour compression circuit as described below, allowing heat to be removed from the building and dissipated from the roof structure.

The invention includes a climate control system which incorporates the heat exchange plate.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings: Figure 1 is a section through part of a tiled roof which incorporates heat exchange plates in accordance with the invention; Figure 2 is a plan view of part of the roof with some of the tiles omitted to reveal the heat exchange plates; Figure 3 is a schematic diagram of a climate control system incorporating the heat exchange plates; Figure 4 shows another use of the heat exchange plates in a wall heating installation; and Figure 5 is a similar view to Fig. 4. showing a later stage in the installation process.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring firstly to Fig. 1, a pitched roof structure 10 includes conventional spaced rafters with rigid foam filling the spaces between the rafters or, in the case of a new roof, structural insulation panels fixed on top of relatively wide-spaced rafters. The roof structure 10 is covered by a waterproof membrane 11, and timber tiling battens 12 are nailed or otherwise secured over the membrane 11 extending transverse to the rafters at an appropriate pitch. Tiles, slates or similar roofing elements 15 (referred to herein simply as "tiles") are engaged with and preferably nailed or otherwise fastened to the tiling battens 12 with the bottom of one tile overlapping the top of the tiles immediately below in a traditional manner. In accordance with the present invention, heat exchange plates 16 are fixed to the battens 12 beneath at least some of the tiles 15, as will now be described in detail.

Fig. 2, shows two of the tiling battens 12.1 and 12.2, with a row of abutting tiles 15 already secured in place on the lower of the two battens 12.2. The heat exchange plates 16A and 16B each comprise a flat heat collector 17 of generally rectangular shape. The distance between the top and bottom edges of each plate is slightly less than that of the tiles, although the distance should be sufficient to span two battens with a slight overlap so that the lower margins of the plates overlie the row of tiles 15 below. The heat collector is preferably formed of a good heat-conducting material such as copper, brass, aluminium etc., and the top edge is turned down through 90 degrees to form a locating flange 18 (Fig. 1) which locates over the top edge of the battens 12. The plates may be secured to the battens by nails, screws or similar fixing elements inserted through one or more holes 19 which are provided for the purpose in the top margin of the collector 17. Each plate is positioned along the batten 12.1 so that the centre line of the plate lies above the abutting edges of two tiles in the row below. In this example there is a gap shown between adjacent plates 16A and 16B, but the plates could abut or even overlap at the edges. Also, the plates could each be two or more tiles wide, e.g. the two illustrated plates 16A and 16B could be formed as a single plate if desired albeit with some loss of coverage at the ends of the rows.

In Fig. 2 each of the heat collectors 17 is drawn partly transparent to reveal a heat exchange tube 20 which is secured to the underside of the heat collector. The tubes 20 may be of copper or other suitable heat-conducting material, and are thermally bonded to the heat collectors, e.g. by soldering, brazing, by means of a heat-conductive glue etc. The tubes are formed with a serpentine or zig-zag configuration to cover a maximum area of the heat collectors 17, in the region between the battens 12. The tubes extend between access holes 22 and 23 which are formed by removing opposite corners of the respective heat collector 17.

It will be noted that the plates 16 are provided in alternating pairs 16A and 16B so that the access hole 23 of one plate 16A is conjoined with the access hole 22 of the next plate 16B. The tubes 22 are connected together within the conjoined holes 22 and 23 by means of compression couplers 24, although other forms of coupler such as soldered couplers, push-connectors or the like may also be used.

It will thus be appreciated that the tubes 20 travel in the gaps between the adjacent battens 12 to form a continuous fluid circulation path. At the opposite ends of a group of interconnected plates the tubes 20 may be connected in series or in parallel with other such groups by means of suitable manifolds, either mounted above, within or beneath the roof structure 10.

When the connections to a row of plates 16 have been completed a row of tiles is placed over the plates and secured to the batten 12.1 in a conventional manner. Tile fixing elements can either be driven through the plates, or one or more apertures 25 can be provided to accommodate the fixing elements.

Since the plates have close thermal contact with the overlying tiles, solar heating of the tiles will transfer heat to the plates so that thermal energy can be transferred to or from the roof via fluid which is circulated through the tubes 20. Since the heat exchange plates are not visible externally they are more acceptable than conventional solar panels, and are generally suitable for use in conservation areas or listed buildings for example. The plates can be installed under a wide range of roofing tiles (interlocking concrete tiles, reconstituted slates etc.), and the original tiles can be removed and reinstalled on top of the plates if desired.

The heat exchange plates provide a useful means of harvesting solar energy, which may be used for water heating as in a conventional solar heating system. Fig. 3 shows how the heat exchange plates can be used as part of a building climate control system in which the plates may provide a heat source from which heat can be extracted by means of a heat pump for operating under-floor heating (as shown), radiators, or fan-powered room heaters. The system also permits air to be cooled by extracting heat from inside a building using various kinds of air coolers, fan-powered, ducted or otherwise, and pumping the heat into the roof.

The roof tiles may dissipate the heat to the external environment or store it for re-use during cooler periods. Removal of heat from the roof can be increased by evaporating stored rain water from the tiles, with any unused water being recovered via the roof guttering which is normally provided.

Referring to Fig. 3, the heat exchange plates 16 are connected to re-circulate fluid, e.g. a solution of antifreeze in water, via an evaporator 31 by means of a pump 32. A non-return valve 33 may also be included, while zone control valves 34 provide a means of balancing the flow through the plates 16. The evaporator 31 forms part of a heat pump of the vapour compression type, in which gaseous refrigerant warmed in the evaporator 31 is pressurised by a compressor 35 before passing through a condenser 36. Cooled refrigerant leaving the condenser passes through a pressure-lowering device such as an expansion valve 37, a capillary restriction, or possibly a work-extracting device such as a turbine, which passes low temperature vaporised refrigerant back to the evaporator 31.

Heat removed by the condenser 36 is carried in another fluid which is re-circulated by a pump 38 through a space heater such as a floor 40 which contains underfloor tubing 39. The floor 40 acts as a thermal heat sink which stores the heat energy for release into the building when required.

By reversing the heat pump the system can also operate to cool a building during hot weather by transferring heat energy from the floor 40 to the roof tiles. Reversal of the vapour compression circuit can be achieved in a known manner by incorporating a reversing valve which switches the compressor 35 to reverse the direction of flow around the circuit. A system of non-return valves may be required to ensure that an expansion valve is still functional with the reverse flow, so that the roles of the evaporator 31 and the condenser 36 are reversed.

The heat exchange plates 16 can also be used to provide an effective, unobtrusive and inexpensive space heating arrangement, which may be used in the reversible heat pump system shown in Fig. 3. As will now be described, the plates can either be left on view or buried in walls, floors or ceilings to act as room heaters similar to traditional underfloor heating tubes, except that the plates cause less disruption during installation.

Referring to Fig.4, which shows part of a typical wall heating installation, the plates 16 are again affixed to appropriately spaced battens 12, which may either be part of a new wall construction or fixed on the surface of an existing wall. The heat-conducting tubes 20 which are thermally bonded to the rear surface of the heat collectors 17 are connected together in the access holes 22 and 23 by means of compression couplers 24, or similar means. The plates may be covered by a layer of render, wall plaster, or walt tiles, for example. This may be facilitated by providing union-covers in the form of small heat-conductive plates, which are fitted over the conjoined access holes 22 and 23 using self-tapping screws 52 or other suitable fixing means. The plates also increase the effective heat-emitting or heat-collecting area, helping to increase the overall efficiency of the installation.

The heating/cooling plates 16 can be used in conjunction with other heating, cooling or heat storage devices such as radiators, underfloor heating pipes, or a thermally insulated direct or indirect hot water cylinder which can be used to store heat collected from a roof during the day for use in warming the building during cooler periods.

Whilst the above description places emphasis on the areas which are believed to be new and addresses specific problems which have been identified, it is intended that the features disclosed herein may be used in any combination which is capable of providing a new and useful advance in the art.

Claims

CLAIMS1. A heat exchange plate for use in a heating or cooling system for installation in a building, the plate including a generally planar heat collector formed of a heat-conducting material having a rear face with top and bottom margins which can be supported against spaced battens in use, an upper edge of the heat collector at said top margin having one or more rearward projections to locate over the respective batten, and in which a fluid conduit is applied to a rear face of the heat collector in thermal contact therewith between the top and bottom margins.
2. A heat exchange plate according to Claim 1 in which the heat collector has at least one access hole which accommodates an end of the fluid conduit.
3. A heat exchange plate according to Claim 2 in which the or each access hole is arranged in an edge region of the plate.
4. A heat exchange plate according to Claim 3 in which the access holes are arranged such that when two of the plates are mounted side-by-side on the same batten the access holes are conjoined.
5. A heat exchange plate according to any preceding claim in which the top margin is provided with fixing holes.
6. A heat exchange plate according to any preceding claim in which the top margin is provided with at least one aperture through which a fixing element may be inserted to affix a roofing element (e.g. a tile) to the respective batten overlying the heat exchange plate.

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7. A heat exchange plate according to any preceding claim when affixed to a top batten extending beneath the top margin.
8. A heat exchange plate according to Claim 7 in which a bottom batten extends beneath the bottom margin.
9. A heat exchange plate according to Claim 7 or 8 in which a roofing element (e.g. a tile) overlies the heat exchange plate affixed to the top batten.
A heat exchange plate according to Claim 7, 8 or 9 in which a plurality of such heat exchange plates are affixed to the top batten in edge-to-edge relationship.
11. A heat exchange plate according to Claim 10 in which the fluid conduits of the adjacent plates are mutually connected to form a continuous fluid circulation path.
12. A heat exchange plate according to Claims 2 and 11 in which cover plates are mounted over the access holes.
13. A heat exchange plate according to Claim 12 in which the cover plates are formed of a heat-conductive material.
14. A climate control system which incorporates a heat exchange plate in accordance with any preceding claim.
15. A climate control system according to Claim 14 which includes a heat pump for transferring heat between a roof structure and a climate -11 -control heat exchanger.
16. A climate control system according to Claim 15 in which the heat pump is reversible, allowing heat to be removed from the climate control heat exchanger and dissipated from the roof structure or collected from the roof structure and transferred to the climate control heat exchanger.
17. A climate control system according to Claim 16 in which the heat pump is reversible by changing the direction of flow around a vapour compression circuit.
18. A climate control system according to Claim 16 or 17 in which the climate control heat exchanger is incorporated in a heat storage facility.
19. A heat exchange plate substantially as described with reference to the drawings.
20. A climate control system substantially as described with reference to the drawings.