FIELD OF THE INVENTION

[0001] The Invention relates to heated flooring. In particular, the invention relates, but is not limited, to insulated flooring with a thermally conductive skin that engages with heated conduits.

BACKGROUND TO THE INVENTION

[0002] Reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in Australia or elsewhere.

[0003] Underfloor heating systems are used in cool climates to heat a room or building. The underfloor heating systems have a heating source provided within flooring of a building to provide a heat from the ground. Not only is it pleasant to have a warm floor surface to walk on, particularly in bare feet, but heat rises from the floor heating the space above it.

[0004] Typically underfloor heating is provided by having a network of interconnected pipes located inside a concrete slab. To heat the flooring, a heated fluid, typically water, is pumped through the pipes in the concrete slab which consequently increases in temperature and conducts heat to the flooring above. However, such hydronic underfloor heating is inefficient as the entire concrete slab has to be heated and significant heat loss occurs through non-room surfaces of the slab, particularly through the underside.

[0005] Hydronic underfloor heating is also expensive to construct and, furthermore, requires a concrete pad. It is therefore not possible to use it with non-concrete based floorings nor retrofit it to existing buildings. Still further, hydronic underfloor heating systems are difficult to maintain. If a blockage or leak occurs, it is generally hard to determine where the blockage or leak has occurred and then, even if determinable, even harder to fix the problem when the pipe is located within the concrete pad.

[0006] An alternative system is to use an electric element which has an electric heating element installed below a floor finish, such as carpet or tiles. In use, the electric heating element uses electricity to increase in heat, which is then conducted to the floor surrounds. While generally simpler and easier to maintain than hydremic systems, electric element systems are relatively inefficient due to high electricity usage in heating the electric element and, like hydronic systems, they too can suffer from heat losses through non-room surfaces.

OBJECT OF THE INVENTION

[0007] It is an aim of this invention to provide a heated flooring system which overcomes or ameliorates one or more of the disadvantages or problems described above, or which at least provides a useful alternative.

[0008] Other preferred objects of the present invention will become apparent from the following description.

SUMMARY OF INVENTION

[0009] According to an aspect of the invention, there is provided a heated flooring system comprising:

an insulated floor panel having a thermally conductive skin layer affixed to a thermally insulated portion of the floor panel, wherein the floor panel has one or more channels in an upper surface thereof;

a heated conduit mounted in at least a portion of the one or more channels of the insulated floor panel; and

a floor surface mounted on top of the insulated floor panel and heated conduit.

[0010] The thermally conductive skin layer of the insulated floor panel is preferably a metal layer. The insulated floor panel preferably comprises two skin layers, one being the thermally conductive skin layer, sandwiching the thermally insulated portion. Preferably the thermally insulated portion is a foam core. Preferably the foam core is derived from a liquid foamable material cured between, and bonded to, the two skin layers. Preferably the foam core is a polyurethane foam core and preferably the liquid foamable material is a liquid foamable polyurethane.

[0011] The insulated floor panel is preferably between 50mm and 200mm thick, even more preferably between 100mm and 150mm thick, and in a preferred form approximately 125mm thick. The insulated floor panel preferably has a thermal resistance R-value of greater than 3, even more preferably greater than 4, and in a preferred form of around 5-6.

[0012] Preferably the insulated floor panel has a plurality of parallel channels in the upper surface. Preferably the thermally conductive skin layer is corrugated having a plurality of parallel ridges with troughs between adjacent ridges. Preferably the plurality of parallel channels are formed from troughs in the corrugations and preferably the floor surface is mounted on the ridges of the corrugations. Preferably the heated conduit is mounted in the troughs using a bracket affixed to the thermally conductive skin layer.

[0013] The heated conduit may be a fluid conduit or an electric element. In a preferred form the heated conduit is a fluid conduit that receives a heated fluid, preferably water, therein. The fluid conduit is preferably a substantially rigid pipe. The pipe may be made of any suitable material, such as copper or plastic. Preferably a single pipe traverses a plurality of parallel channels in the upper surface of the insulated floor panel. The pipe is preferably sized to seat within the one or more channels in an upper surface of the insulated floor panel. Preferably the pipe is mounted to at least a portion of the one or more channels of the insulated floor panel such that an outer surface of the pipe engages with the thermally conductive skin layer.

[0014] The heated flooring system preferably further comprises a heat pump in fluid communication with the fluid conduit. Preferably the heat pump is a heat pump hot water system that may also be utilised as a standalone hot water supply. Preferably a pump is provided to circulate heated water from the heat pump hot water system through the fluid conduit. Preferably the pump has a low circulation rate; preferably less than 20L/minute, even more preferably less than 10L/minute, and in a preferred form of approximately 5L/minute.

[0015] Preferably a tempering valve is provided to reduce the temperature of the heated water from the heat pump hot water system before circulation through the fluid conduit. Preferably the tempering valve reduces the temperature of the heated water from the heat pump hot water system using return water output from the fluid conduit. The temperature of the heated water from the heat pump hot water system is typically approximately 60°C+ and the tempering valve preferably reduces the temperature of the heated water to approximately 20 to 45°C, even more preferably to approximately 25 to 40°C before it is circulated through the fluid conduit.

[0016] According to another aspect of the invention, there is provided a building comprising:

a floor including the heated flooring system as described herein; a heat pump hot water system in fluid communication with the heated conduit of the heated flooring system;

external walls located around the perimeter of the floor; and internal walls located within the perimeter of and on the floor.

[0017] According to another aspect of the invention, there is provided a method of heating a heated flooring system as described herein, the method comprising the steps of:

heating a fluid; and

pumping the heated fluid through the conduit.

[0018] According to yet another aspect of the invention, there is provided a method of heating a flooring system, the method comprising the steps of:

heating a fluid; and pumping the heated fluid through a conduit mounted to a thermally conductive skin layer in a channel of an insulated floor panel.

[0019] Preferably the step of heating a fluid comprises heating the fluid using a heat pump hot water system. The step of heating the fluid using a heat pump hot water system may further comprise the step of reducing the temperature of water from the heat pump hot water system using a tempering valve or heat exchanger. Preferably the tempering valve mixes return water from an outlet of the conduit with heated water from the heat pump hot water system to deliver the heated fluid at a predetermined temperature. The step of pumping the heated fluid through a conduit preferably comprises using a low circulatory rate pump to circulate the heated fluid through the conduit.

[0020] Further features and advantages of the present invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021 ] By way of example only, preferred embodiments of the invention will be described more fully hereinafter with reference to the accompanying figures, wherein:

[0022] Figure 1 is a cutaway perspective view of an underfloor heating system according to an embodiment of the invention;

[0023] Figure 2 is a cutaway top view of the underfloor heating system illustrated in figure 1 ; and

[0024] Figure 3 is a cross sectional view of the underfloor heating system illustrated in figure 1.

DETAILED DESCRIPTION OF THE DRAWINGS

[0025] Figures 1 to 3 illustrate an underfloor heating system 10 having an insulated floor panel 12, a heated conduit in the form of a water pipe 30, and a floor surface 40. An internal wall 50 is also illustrated extending upward from the floor surface 40.

[0026] The insulated floor panel 12 has a thermally insulated portion in the form of a foam core 14 sandwiched between an upper thermally conductive skin layer 16 and a lower skin layer 18. Both the upper thermally conductive skin layer 16 and the lower skin layer 18 are bonded to the foam core 14 during manufacture of the panel where a liquid foamable polyurethane is injected and expands into a cavity formed between the skin layers 16 and 18 and then cures between, and bonds to, the two skin layers 16 and 18. The resultant insulated floor panel 12 according to a preferred embodiment is approximately 125mm thick and has a very high thermal conductivity resistance, with an R-value of approximately 5-6, providing a highly insulated flooring panel 12.

[0027] The upper thermally conductive skin layer 16 is corrugated metal, having corrugations in the form of alternating ridges 20 and troughs 22 which in a preferred embodiment have a height differential of approximately 25mm. The troughs 22, provide a plurality of parallel channels which can receive the water pipe 30 therein as illustrated. The water pipe 30 is mounted in the troughs 22 using brackets 32 which screw into the upper thermally conductive skin layer 16, holding the water pipe 30 in the trough 22 and in engagement with the upper thermally conductive skin layer 16 (seen most clearly in figure 3).

[0028] The floor surface 40 is mounted on top of the insulated floor panel 12, abutting the ridges 20 of the corrugated upper thermally conductive skin layer 16. The floor surface 40 may be any suitable flooring material, but is typically selected to provide sufficient thermal conductivity from the thermally conductive skin layer 16 of the insulated floor panel 12. Internal wall 50 may be located on top of the floor surface 40 or, more preferably, is mounted to the insulated floor panel 12 with the floor surface 40 going around the wall 50. [0029] The underfloor heating system 10, floor surface 40, and internal wall 50 all form parts of a building which has external walls (not shown). At least the external walls and ceiling (not shown) are thermally insulated panels, similar to the thermally insulated panel 12 used in the underfloor heating system 10, to provide a full insulated interior space in the building. The windows are also typically double or triple glazed to reduce any heat losses and improve the thermal efficiency of the building.

[0030] The water pipe 30 of the underfloor heating system 10 Is typically a single long pipe with bends 34 at the ends of the insulated floor panel 12 to allow the 30 pipe traverse a plurality of troughs 22 of the insulated floor panel 12 in a serpentine manner. The bends 34 are relatively small connectors, approximately 23mm in diameter, located adjacent the external walls such that the water pipe 30 traverses full lengths of the floor.

[0031] The water pipe 30 has an inlet 36 and outlet 38 which are connected to a hot water system (not shown) which in a preferred embodiment is a heat pump hot water supply. It will be appreciated that other hot water supplies may also be utilised, but preferably the hot water supply is an energy efficient hot water source such as a heat pump, solar, or gas water supply. Any external pipes (not shown), such as those connecting the water pipe 30 to the heat pump hot water system, are insulated to prevent any heat loss on their way to or from the underfloor heating system 10.

[0032] The heat pump hot water system provides hot water to the building, with the underfloor heating system 10 using a low circulation rate pump, such as a Grundfos UPS20-60N which has a low circulatory rate of approximately 5L/min, to draw warm water from the heat pump hot water system when needed. The inlet 36 and outlet 38 of the water pipe 30 are both connected to the heat pump hot water system so that the quantity of water in the heat pump hot water system does not change. A pressure reduce (not shown) is typically provided to reduce the relatively high water pressure from the heat pump hot water system, e.g. ~10bar, to a lower pressure, e.g. ~1 bar, for circulation in the water pipe 30.

[0033] In a preferred embodiment the water pipe 30 is connected to the heat pump hot water system by a tempering valve (not shown )to reduce the temperature of the water entering the water pipe 30 from the heat pump hot water system. The tempering valve has a hot and cold inlet and mixes the two to provide a mixed outlet at a predetermined temperature. The hot inlet is connected to the heat pump hot water system, the cold inlet is connected to the outlet 38 of the water pipe 30, and the mixed outlet is connected to the inlet 36 of the water pipe 30. Any 'cold' water from the outlet 38 not used by the tempering valve is returned to the heat pump hot water system to replenish the water drawn by the hot inlet of the tempering valve. In a typical embodiment, the heat pump hot water system will heat and store water at around 60°C and the tempering valve will reduce the temperature to about 25-40°C using cooler water from the outlet 38 of the water pipe 30.

[0034] The floor of the building may be made from a plurality of insulated panels 12 arranged adjacent each other to form a floor plane. In a preferred embodiment insulated panels 12 extend fully between external walls in a direction that is parallel to the troughs 22 of the insulated panels 12 and then a plurality of insulated panels 12 are arranged adjacent each other in a direction perpendicular to the troughs 22 of the insulated panels 12. The underfloor heating system 10 is structurally sound and can be mounted to various building foundations including on joists or concrete pads.

[0035] In use, hot water is drawn by the circulatory pump from the heat pump hot water cylinder, via the tempering valve, into the water pipes 30. The heat of the water in the pipes 30 is conducted to the thermally conductive skin layer 16 of the insulated floor panel 12. The circulatory pump is typically controlled by one or more thermostats located in the building to selectively actuate the heating system 10 when needed. As warm water is drawn from the heat pump hot water system, the internal temperature of the heat pump hot water system will decrease. The heat pump hot water system has its own thermostat and will automatically turn itself on, when necessary, to maintain a hot water supply.

[0036] Because the insulated floor panel 12 has a thermally insulated portion in the form of a foam core 14 on one side, the heat that is conducted from the pipes 30 to the thermally conductive skin layer 16 cannot escape downward. Rather, it is efficiently conducted across the thermally conductive skin layer 16 and the floor surface 40. The heated floor surface 40 not only provides a pleasantly warm surface to walk on, but also heats the air above the floor surface 40 and hence the interior of the building.

[0037] Advantageously, the underfioor heating system 10 provides a cost effective and energy efficient method of heating a building. The underfioor heating system is easily implemented at time of construction of a building, or can even be retrofitted to existing buildings. Maintenance of the underfioor heating system 10 is considered to be negligible but, if necessary, it is relatively straight forward. The water pipes 30 are relatively accessible underneath the flooring 40 for any service and repair that may be required.

[0038] The underfioor heating system 10 is highly energy efficient as the insulated floor panel 12 does not allow heat from the underfioor heating system 10 to escape downwards to any non-room surfaces. Furthermore, as the underfioor heating system 10 does not need to heat up a large mass, such as a concrete slab, efficiency is further improved and temperature response times of the underfioor heating system 10 are much quicker.

[0039] Construction of the underfioor heating system 10 is relatively straight forward and cost effective, particularly since the hot water supply, preferable a heat pump hot water supply, is already required to supply hot water to the building. The additional heating load required for the underfioor heating system 10 is considered to be relatively minimal and, accordingly, a heat pump hot water supply chosen to provide a general hot water supply to a building will have sufficient capacity to also provide the heating required for the underfioor heating system 10. [0040] In this specification, adjectives such as first and second, left and right, top and bottom, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one or more of that integer, component, or step etc.

[0041] The word corrugated is considered to include any surface with corrugations which may be spaced equidistantly or have varying spacing. Furthermore, the ratio between the troughs and valleys of the corrugations need not be even (1 :1 ) but rather may include other ratios such as having a trough separated by a much wider ridge.

[0042] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The invention is intended to embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.

[0043] In this specification, the terms 'comprises', 'comprising', 'includes', 'including', or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.