GB2284660A - Flow director and thermal panel for heat sources - Google Patents

Abstract

A heating system for domestic or industrial heating has a fluid flow director (21) having a number of outlets which direct air over the surface(s) (24, 25) of a heat source (15). The director is designed so that the fluid flow emerging from each outlet (22, 23) does so at differing fluid flow velocities so that the composite fluid flow emerging at the top of the heat source is directed towards a predetermined region such as the centre of the space to be heated. The system also includes a surface mounted reflective thermal panel (18) located adjacent to the heat source. The thermal panel has a plurality of abutting parallel channels (12, figure 1) in its surface, the channels having a concave circular or conic cross-section. Adjacent channels abut along their edges to form ridges (11). <IMAGE>

Description

HEATING SYSTEM The present invention relates to a system for enhancing or modifying the behaviour of forced and natural convective fluid flow in thermal or other applications.

In industrial or domestic heating systems, it is known to use reflective screens or panels to improve the efficiency of the systems. The reflective screens radiate the heat to a pre-determined location or back towards the heater. However some screens have a reduced effectiveness as they act only on the radiated heat and also they tend to collect dust on their outer surfaces due to deposition from the hot air streams.

Thus according to the present invention there is provided a thermal panel, preferably reflective, having a surface at least a part of which has a plurality of substantially parallel channels, the channels abutting along their edges to form parallel ridges. The channels preferably have a concave, circular or conic cross-section.

The ridges desirably form relatively sharp edges having small radii of curvature compared to the curvature of the channel's profile. Also preferably the surface is reflective to reflect heat rays back towards a heating body, a space to be heated or other desired direction.

The panel may be used alone or may be used together with ancillary components. Thus according to a further aspect of the invention there is provided a thermal system comprising a wall or surface mounted panel as hereinbefore described, a heating source located substantially adjacent to the panel and means for causing fluid air flow between the radiator and panel whereby a heating effect may be achieved. The means for causing fluid, e.g. air, flow between the radiator and panel may be natural convection and also includes a fan or blower to cause and/or assist the fluid flow The heating source is preferably a radiator.

According to a further aspect of the invention there is provided a heating system comprising a heating source and a fluid flow director, the director having one or more outlets adapted to direct fluid flow over one or more surfaces of the heating source whereby the fluid flow is directed to a pre-determined location.

The fluid flow director may be in the form of a nozzle having one or more outlets. In a preferred embodiment, a fluid flow director in the form or a nozzle has a plurality of outlets adapted to direct fluid flow, usually air, over the surface of a heat source in the form of a radiator.

The outlets for the nozzle may comprise single longitudinal openings or a plurality of openings in series. The openings may comprise slots, orifices, holes etc.

In the case of heating sources in the form of multi element radiators, the nozzle may have an appropriate number of outlets to direct fluid flow over each surface of the radiator. Thus for example, a two element radiator could be associated with a nozzle having three outlets, one for each outer surface and a centrally directed outlet.

The fluid flow director is advantageously designed so that the fluid flow emerging from each outlet does so at differing fluid flow velocities so that the composite fluid flow emerging at the top of the radiator is directed towards a pre-determined region e.g. the centre of the space to be heated.

According to a still further aspect of the invention there is provided a heating system comprising a thermally reflective panel as hereinbefore defined, a fluid flow director and a heating source.

The invention will now be described by way of example only and with reference to figures 1 to 10 of the accompanying drawings.

Figure 1 shows a perspective view of one embodiment of a thermal panel according to the invention.

Figure 2 shows a view in elevation of a thermal panel and adjacent heating radiator which shows the pattern of thermal flow Figure 3 shows a view in elevation of a wall-attached thermal panel and heating radiator used with an assisting blower or fan.

Figure 4 shows a view in elevation of a nozzle/radiator system used with an insulative isolator panel such as a foam backed foil.

Figure 5 shows a view in elevation of a thermal system comprising a heating radiator, a reflective panel attached to a wall and a nozzle.

Figure 6 shows a view in elevation of a thermal system comprising a heating radiator, a reflective panel attached to a wall and a nozzle which shows the ability to direct thermal flow in a desired direction.

Figure 7 shows a perspective view of one embodiment of a nozzle for use in the thermal system Figure 8 shows a transverse sectional view of a nozzle arrangement comprising an aerofoil.

Figure 9 shows a view in elevation of double panelled heating radiator having an associated nozzle with a triple outlet Figure 10 shows a longitudinal sectional view of a nozzle being adapted for use as an outlet in an air conditioning system.

In figure 1, a flow projector interface in the form of a panel (10) is shaped so as to form a series of spanwise ridges (11). Each ridge is separated from adjacent ridges by substantially concave troughs (12) or valleys of the order of 10 to 60 mms in width and ranging from 3 to 30 mms in depth. Each of the troughs profiles are arcs of circular or conic sectional curves. The ridges are formed at the intersection of the adjacent troughs, The ridge peaks form relatively sharp edges having small radii of curvature relative to the radii of curvature of the troughs sectional profiles. The troughs (12) between the ridges (11) are designed to act as 'scoops' to project air flowing substantially perpendicular to the sides of the ridges outwardly away from the ridges so as to divert the flow of air away from the surface of the panel.The effect of the troughs between the ridges is also to trap air between the ridges thereby increasing the thickness of the fluid boundary layer near the surface of the panel.

The surface of the panel is made reflective to thermal radiation by depositing a thin metallic film e.g. aluminium onto its surface by any suitable metallisation process e.g. sputtering. This treatment process minimises the loss of radiant thermal energy by reflecting it back to a more thermally useful region. The curved concave troughs are particularly suited, when metallised, to reflecting incident thermal radiation back to the radiation emitter, in this case the heating radiator. The semi-parabolic surfaces of the troughs allow focusing of the incident radiation back onto the radiator thereby giving in increase in the efficiency of the heat transfer process.

The continuous surface provided by the ridges and troughs of the panel especially when taken in conjunction with a membrane or skin or other such backing surface applied to the reverse face of the panel forms a series of enclosures or pockets containing a fluid such as air. The fluid filled enclosures can fulfil the function of insulative cushions allowing the panel to act as a thermal insulator thereby inhibiting the transfer of thermal energy across its thickness.

The panel is especially designed to be attached to insulative substrates such as cork or plastic foam with the object of providing an effective insulative interface. A particular advantage of using a separate backing surface to the panel before attachment to its eventual mounting location is that of ease of fitting. A suitably shaped and sized panel modulr may be fabricated with a fully sealed series of fluid filled pockets. The module may then be easily attached to its mounting location with fasteners without the requirement to form a continuous fluid seal between the panel and its mounting surface. This can facilitate removal of the module for cleaning or other purposes.The panel may also be installed in a non planar mounting configuration by bending the upper part of the panel towards the radiator so as to increase the effect of convection as in a chimney for example. This allows for great flexibility in view of the variability of the distance between wall and radiator in different locations or applications. Also it is possible to attach the panel to its mounting surface, desirably attached continuously to the mounting surface to give a fluid tight seal around its periphery.

In figure 2, the panel (13) is shown attached to a wall (14) and adjacent to a heating radiator (15). The figure shows the arrangement in use and indicates the enhancement of convective air flow between the panel (13) and radiator (15) so as to heat the room more efficiently.

In figure 3, the arrangement of figure 2 is shown with the addition of a fan or blower (16) to augment the convective air flow between the panel and radiator. Also a lip (17) or projection at the upper or downstream end of the panel may be used to help divert the air flow over the radiator.

Whilst the flow projector interface or panel has been designed so that it can be used independently for enhancing fluid flow past a heat source such as a heating radiator, it may also be used with benefit with an efflux or nozzle component as hereinafter described.

In figure 4, a heat panel (18) is fixed to a wall (19) and adjacent to a heating radiator (20). The panel may be of any conventional type. A nozzle (21) is located below the radiator and has a pair of slot-like outlets (22,23) adapted to direct air upwards and over the front and back surfaces (24,25) of the radiator (20). Figure 5 shows a similar arrangement to figure 4 showing the use of a panel (26) according to the invention and having a lip (27) to direct air flow.

The air emerging from each of the outlets may do so at differing flow velocities. The outlets may be arranged so as to cause the flow streams flowing over the front and back radiator surfaces to converge and form a single flow stream which may be directed into a preferred region such as the centre of a room to be heated. Thus in figure 6, to create the conditions for the air flow around the radiator to be directed into the body of the room, the fluid particles in the composite stream of warmed air at the top (28) of the radiator must rotate from the faster air boundary towards the slower air boundary so that the resultant flow tends towards the faster air flow perimeter.This means that the nozzle outlet (23) providing the slower air flow stream should be positioned immediately behind and adjacent to the radiator and the nozzle outlet (22) providing the faster air flow stream is positioned adjacent the front edge of the radiator away from the panel. An advantage of having a forced air stream behind the radiator is that the convective heat transfer behind the radiator would be increased significantly due to forced convection therefore minimising heat losses from this high heat loss area directly behind the radiator. Also some of the heat energy that would otherwise be lost to the wall directly behind the radiator is transferred to the forced air stream and may be deployed to warm the room as the air stream is spun into the body of the room with a lateral component which reduces migration of the warm air to the ceiling.

The range of possible configurations is wide. Thus the nozzle outlets may comprise single longitudinal openings or two or more openings in series. The openings may comprise slots, orifices etc.

An embodiment of a nozzle is shown in figure 7. The nozzle body (33) comprises two adjacent parallel slots (30,31) which are fed by a common source of fluid e.g. air. The cross section of the body of the chamber supplying the slots is divided by a baffle (32) so as to enable different air flows to be applied to each slot. The slots (30,31) are sized to facilitate these differing air flows. The slots in this example are located in close proximity to each other to facilitate the merging of the air flow streams near to the body of the nozzle.

The source of air flow from the nozzles may be a suitable air mover such as a fan or blower, the fan of blower feeding one or more outlets.

The outlets may be formed, for example, from a suitably configured aerofoil section mounted in a slot as shown in figure 8 where the differential air flow through each of the slots (35,36) is achieved by an aerofoil (34) mounted in slot (37). Alternatively, a series of adjacently mounted aerofoils may be used. This would provide a velocity gradient through the thickness of the merging fluid flow from the areas about the chordlines of the aerofoil thereby causing vorticity and curvilinear motion of the air.

Any suitable method may be used to provide a velocity gradient through the thickness of the composite fluid flow so as to cause vorticity and curvilinear motion of the air. In the case of a central heating radiator for example, there are in existence radiators made up of two or more panels (40,41) mounted face to face (figure 9).

This has the effect of forming spaces or voids (42) between adjacent panels of the radiator (43). Thus in nozzle (47), outlets (44,45,46) may be placed under each void space so that the air streams emerging from each of the outlets have the fastest air flow outlet towards the front of the radiator and the slowest air flow outlet positioned at the radiators rear face. That is to say the air flow stream at the back of the radiator is slower than that emerging through the void (42) which is itself slower than the air stream emerging at the front face of the radiator. Thus the principle of forced convective heat transfer may be employed at each panel making up a given radiator.

The velocity gradients through the composite stream of air which forms above the radiator also give rise to vorticity and curvilinear motion of the warm air causing flow into the body of the room.

The system described above is suitable for retrofitting to existing central heating systems although new build systems may also benefit by the incorporation of the invention as herein described.

The nozzle may also be adapted for use in warm or cold air blowing systems ducts such as air conditioning and portable or fixed heaters and coolers as shown in figure 10 for example. The nozzle may in these cases be employed as the outlet for warm or cool air or fluid flows so that the beneficial effects of curvilinear fluid particle flows may be enjoyed. These beneficial effects may be for example the better deployment of warm air streams from high mounted warm air heating duct outlets in that the naturally buoyant upward bound air flows may be diverted into the body of the heated space thereby increasing comfort and reducing losses and so consequently operating costs.The fluid flows emerging from the duct (51) may be divided into two streams of fluid by use of a repositionable baffle (52) which divides the main duct (51) into two portions one convergent (53) and the other divergent (54), that is a nozzle and a diffuser respectively. Rotation of the baffle about its pivot (55) can allow repositioning for adjusting the fluid flow direction.

Other benefits of curvilinear motion of fluid particles may be for example increasing warm air distribution from a portable fan heater so that the warmed air is kept at a lower room level for a longer duration thereby overcoming the natural tendency of the warm air to rise quickly. A further benefit may be for example in the case of floor mounted room coolers where the propensity of cold air to sink to lower room levels may be overcome by giving the cold air an upward and outward boost to ensure more uniform cooling of the surroundings.

The nozzle has also been designed to be used in conjunction with more conventional insulative heat shielding materials such as foam backed reflective foil and other such products to complement these materials in their operation by giving them a convective dimension when required.

Claims (24)

Claims

1. A heating system comprising a heating source and a fluid flow director, the director having one or more outlets adapted to direct fluid flow over one or more surfaces of the heating source whereby the fluid flow is directed to a predetermined location.

2. A heating system according to claim 1 in which the fluid flow director is a nozzle having one or more outlets.

3. A heating system according to claim 1 or claim 2 in which the fluid flow director is in the form of a nozzle having a plurality of outlets adapted to direct fluid flow over the surface of a heat source.

4. A heating system according to any of claims 1 to 3 in which the outlets for the nozzle comprise single longitudinal openings or a plurality of openings in series.

5. A heating system according to claim 4 in which the openings are slots, orifices, or holes.

6. A heating system according to any of claims 1 to 5 comprising a thermal panel

7. A heating system according to any of the preceding claims in which the thermal panel has a surface at least a part of which has a plurality of substantially parallel channels, the channels abutting along their edges to form parallel ridges.

8. A heating system according to any of the preceding claims in which the thermal panel is reflective

9. A heating system according to any of the preceding claims in which the thermal panel has channels having a concave, circular or conic cross-section.

10. A heating system according to any of the preceding claims in which the ridges of the panel form relatively sharp edges having small radii of curvature compared to the curvature of the channel's profile.

11. A heating system according to any of the preceding claims in which the surface of the panel is reflective to reflect heat rays back towards a heating body, a space to be heated or other desired direction.

12. A heating system as hereinbefore described and with reference to figures 1 to 10 of the accompanying drawings

13. A thermal panel having a surface at least a part of which has a plurality of substantially parallel channels, the channels abutting along their edges to form parallel ridges.

14. A thermal panel according to claim 13 which is reflective

15. A thermal panel according to claim 13 or claim 14 in which the channels have a concave, circular or conic crosssection.

16. A thermal panel according to any of claims 13 to 15 in which the ridges form relatively sharp edges having small radii of curvature compared to the curvature of the channel's profile.

17. A thermal panel according to any of claims 13 to 16 in which the surface is reflective to reflect heat rays back towards a heating body, a space to be heated or other desired direction.

18. A thermal panel as herein before described and with reference to figures 1 to 10 of the accompanying drawings.

19. A thermal system comprising a wall or surface mounted thermal panel according to any of claims 13 to 18, a heating source located substantially adjacent to the panel and means for causing fluid air flow between the radiator and panel whereby a heating effect may be achieved.

20. A thermal system according to claim 19 in which the means for causing fluid, flow between the radiator and panel is natural convection or a fan or blower to cause and/or assist the fluid flow.

21. A thermal system according to claim 19 or claim 20 in which the heating source is a radiator.

22. A thermal system as herein before described and with reference to figures 1 to 10 of the accompanying drawings.

23. A method of heating an enclosed space by use of a heating system or thermal system according to any of claims 1 to 12 or 19 to 22.

24. A method of heating an enclosed space by use of a heating system or thermal system as hereinbefore described and with reference to the accompanying drawings.