Field of the Invention

The invention relates to heating pools and other bodies of water such as spas, and to methods of installing pool heating.

Background of the Invention

Popular methods of pool heating includes heating the pool water by running the water through solar collectors, or heating the pool water via heat pumps or gas boilers.

These systems pump the water from the pool to the heat source, heat the pool water, and then return the pool water to the pool. Despite the numerous systems available on the market these heating solutions can be inefficient and expensive to run and alternative means of heating pools draw interest if cost and efficiency savings can be made. It is in light of this problem that the current invention was conceived.

Summary of the Invention

The invention provides a pool radiator comprising: a substantially rigid and planar body having a fluid inlet and a fluid outlet, the body having a passage connecting the fluid inlet to the fluid outlet, wherein the body transfers heat from fluid in the passage through the body to an exterior of the body.

By providing a pool radiator that transfers heat from fluid in the passage through the body to an exterior of the body it is possible to mount the radiator so that it heats the shell of a pool, which in turn heats the water in the pool. Using such a system can increase the efficiency of a pool heating system.

The term "substantially rigid" is intended to define a structure that may have some flexibility but is strong enough to not collapse during construction of the pool. For example, during construction of a pool with a concrete shell the substantially rigid body is flexible enough to withstand bending stresses without cracking yet rigid enough to not collapse under the weight of the concrete that is applied on top of the body.

Furthermore, components can be bumped or stepped on during pool construction without damage. The term "substantially rigid" is therefore also intended to include that the body is rigid enough to sustain such accidental impacts without permanent deformation.

The passage can comprise a plurality of channels. The channels can be formed internally of the body. Alternatively, the passage can comprise a first channel and a second channel defined by the body. The first channel can be substantially

perpendicular to the second channel. The body can have a plurality of first and second channels that form a body having a waffle-type structure with through-openings between the channels so that when concrete is sprayed it flows through the openings and surrounds the waffle-type structure.

The first channel can have a non-circular cross section, for example a square cross section. The body can be formed as a single unit. The inlet can comprise a spigot protruding from the body so that the body can be connected to water transfer piping or to another similar pool radiator. The spigot can be integrally formed with the body. The body can be moulded with the passage.

The body can be formed by a series of substantially rigidly interconnected pipes that each form a passage. At least one length portion of the interconnected pipes can be parallel. The pipes can be connected together to form a planar structure using reinforcement bar. The radiator can be made from a plastics material. The radiator can have a plurality of outlets. The passages can be approximately 100mm to 150mm apart. Preferably the passages are approximately 125mm centre-to-centre apart. The maximum dimensions of the body can be 1 150mm x 1150mm. The maximum dimensions of the body may be 1050mm x 1050mm. The radiator may include more than one substantially rigid and planar body, wherein the bodies are interconnectable in fluid communication.

The invention also provides a method of building a pool shell with a radiator including:

• installing reinforcing bar and a radiator as claimed in any one of the preceding claims in a base and/or sides of a pre-prepared pool pit;

• applying concrete to the base and sides of the pool pit and embedding the reinforcing bar and the radiator in concrete;

• drying the concrete to form a pool shell installed with the radiator. The method can include installing the radiator in a base of the concrete pool shell.

Embedding the radiator can include fully encasing the radiator in the pool shell or partly encasing the radiator in concrete by having a part of the radiator lying against the pool pit. The method can also include attaching connecting pipework to an inlet and an outlet of the radiator before installing the concrete, wherein the pipework leads to an exterior of the pool pit. The connecting pipework can be attached to a boiler. The invention also provides a method of building a pool shell with a radiator including:

• locating a radiator as claimed in any one of claims 1 to 22 adjacent to a pool shell; and

• installing insulation to cover an exterior of the pool shell and the radiator to insulate the exterior of the pool shell and couple the radiator to the exterior of the pool shell.

The method can include locating the radiator at the base of the pool shell. The method can include locating the radiator adjacent to a fibreglass pool shell. The method can include attaching connecting pipework to an inlet and an outlet of the radiator. The connecting pipework can be attached to a boiler.

Brief Description of the Drawings

An embodiment, incorporating all aspects of the invention, will now be described by way of example only with reference to the accompanying drawings in which;

Figure 1 is a cross-sectional view of a pool shell with a radiator installed in the pool shell;

Figure 2 is a cross-sectional view of an alternative pool shell the radiator shown in Figure 1 installed in the pool shell;

Figure 3A is an isometric view of the pool shell shown in Figure 1 ;

Figure 3B is a detail side view of the detail 'A' indicated in Figure 3A;

Figure 3C is a cross-sectional view of the detail shown in Figure 3B; Figure 4A is an isometric view of an alternative radiator; Figure 4B is a cross-sectional view of the internal structure of the radiator in Figure 4A; Figure 4C is a cross-sectional view of an alternative internal structure of the radiator in Figure 4A;

Figure 4D is a plan view of two radiators shown in Figure 4A connected together in series;

Figure 5 is a schematic of the closed loop heating system connected to a radiator; Figure 6A is a plan view of another alternative radiator; Figure 6B is a plan view of the radiator of Figure 6A with additional outlets; Figures 7A to 7C are cross-sectional views of alternative channel shapes; Figure 7D is a cross-sectional view of two channels side-by-side; and

Figure 8 is a plan view of another alternative radiator.

Detailed Description of Preferred Embodiments of the Invention

Figures 1 to 8 illustrate a pool radiator 10a, 10b, 10c, 100, 200, 300 comprising: a substantially rigid and planar body 20, 120, 220, 320 having a fluid inlet 21 and a fluid outlet 22. The body 20 has a passage 30, 130, 230 connecting the fluid inlet 21 , 121 , 221 , 321 to the fluid outlet 22, 122, 222, 322. The body 20, 120, 220, 320 transfers heat from fluid in the passage 30, 130, 230, 330 through the body 20, 120, 220, 320 to an exterior 24, 124, 224, 324 of the body 20, 120, 220, 320. When placed close to an inner wall (not shown) of a pool heat from heated fluid, typically water, in the passage

30, 130, 230, 330, radiates through the body 20, 120, 220, 320 and through the inner wall of a pool to directly heat the water in a pool.

Referring to Figures 1 and 2, two embodiments of a pool 90 with a radiator 10a installed are shown. Figures 1 and 3A to 3C illustrate a pool with a concrete pool shell

1 10. The body 20 of the radiator 10a is formed by a series of substantially rigidly interconnected pipes 40 that each forms a passage 30 connecting the fluid inlet 21 to the fluid outlet 22. Three radiators 10a, 10b, 10c are shown in the pool 90 in Figures 1 and 3A to 3C. In particular, two or more of the pipe 40 may lie in a single plane to form a substantially rigid and planar body, shown as bottom radiator 10a and side radiators 10b, 10c. The pipes 40 run lengthwise of the pool and a length portion the

interconnected pipes are parallel. The pipes 40 are embedded in the concrete shell during construction. The pipes are made from a plastics material, for example PEX tubing (cross-linked polyethylene tubing).

A heating fluid is pumped in a closed loop through the pipes 40 in the radiators 10a, 10b, 10c. The thermal energy from the heating fluid transfers through the body 20 (i.e. the walls of the pipes 40) to an exterior of the body 20. The thermal energy is absorbed by the concrete in the concrete pool shell 95. The thermal energy in the concrete is then transferred to the water in the pool, thereby heating the water in the pool. The radiator relies on heating the concrete shell through conduction. The concrete shell then heats the water of the pool through conduction (the pool water in contact with the shell) and convection (the movement of the pool water brought on by the temperature difference in the pool water).

The thermal mass of the concrete shell 95, which is heated and kept at a substantially constant temperature, helps to ensure a more stable water temperature in the pool 90. In addition, once the concrete shell 95 is initially heated it requires minimal energy to maintain the temperature of the shell. This is possible as the ground functions as a good insulator, and the majority of the shell (with the exception of the top edges) is not in contact with the ambient air (in contrast to the water in the pool).

Referring to Figure 3A to 3C, during installation reinforcing bar 96 is positioned in the base and sides of a pre-prepared pool pit. The pipes 40 are then conveniently attached to the reinforcing bar 96, for example by tying the pipes 40 to the reinforcing bar 96, to hold the pipes in place during application of the concrete to form the concrete pool shell 96. In other words, the pipes are interconnected using reinforcement bar to form a planar structure. The concrete can be applied in a single step or, alternatively, in a two- stage or multi-stage process. Referring to Figure 3C, the first stage lays an outer portion 97 of the concrete shell 95, after which the reinforcing bar 96 and pipes 40 are positioned. Once the reinforcing bar 96 and pipes 40 are in place the second inner layer 98 of concrete is applied to form the complete concrete shell 95. For

convenience, the concrete is applied, or sprayed, as shotcrete, however any suitable concrete laying process can be used.

Referring to Figure 2, an alternative embodiment of the radiator is shown with pool 90 having a fibreglass shell 91. In a similar way to the concrete shell 95 in Figure 1 , the heat energy from the heating fluid in the pipes 40 of the radiators 10a, 10b, 10c is transferred through the walls of the pipes 40 to an exterior of the pipes 40. Insulation 50 covers the exterior of the fibreglass shell 91. The insulation 50 also covers the radiators 10a, 10b, 10c. The insulation 50 couples the radiators 10a, 10b. 10c to the exterior of the fibreglass pool shell 91. The insulation 50 reduces heat loss from the water in the pool. The heating fluid is pumped in a closed loop through the pipes 40 in the radiators 10a, 10b, 10c. The thermal energy from the heating fluid transfers through the body 20 (i.e. the walls of the pipes 40) to an exterior of the body 20. The thermal energy is absorbed by the insulation 50 through conduction. The thermal energy in the insulation 50 is then transferred to the water in the pool, thereby heating the water in the pool.

The heating fluid, which is connected to a heat source 1 10 in a closed loop, does not mix with the pool water. In other words, the pool water itself is not pumped away from the pool to be heated and then pumped back into the pool (as is common with pool heating systems). By having a closed loop any heating fluid can be used. For example, standard tap water (e.g. unchlorinated water) can be used in the closed loop, which has the benefit of not requiring the components in the closed heating loop to be able to tolerate pool chemicals etc. Glycol (anti-freeze) can be added to the water if required.

Referring to Figure 5, a schematic of the closed loop is shown. The closed loop has a heat source 60, a pump 65 and one or more radiators 10. As described above, the radiator is embedded in either a concrete pool shell, or in insulation surrounding the exterior of a fibreglass pool shell. The heat source 60 can be any device suitable for supplying heat to the heating fluid that is pumped through the radiator 10. For example, heat can be supplied to the heating fluid using a boiler system, a heat pump, energy harvested from a solar panel (either electrical or thermal), or electricity. Using a heat pump, for example, can provide highly efficient heating of the pool water, as a heat pump can have a co-efficient of performance 3 to 4 times higher than heat generated from an electrical resistance system. This is achieved by relying heavily on heat energy from the environment. As illustrated in Figure 5, the working fluid in the closed loop does not come into contact with the water in the pool, allowing any suitable working fluid to be used in the closed loop.

Referring to Figures 4A and 4B, an alternative a pool radiator 100 is shown. The radiator 100 has a substantially rigid and planar body 120 having a fluid inlet 121 and a fluid outlet 122. The body 120 has a passage 130 connecting the fluid inlet 121 to the fluid outlet 122. The body 120 transfers heat from fluid in the passage 130 through the body 120 to an exterior 124 of the body 120. The body 120 is a hollow rectangular cuboid with six panels (top 140, bottom 141 , front 142, back 143, left 144 and right 145). The top and bottom panels 140, 141 have much greater surface area than the other panels. For example, the top and bottom panels have a surface area that is at least two times larger than any of the other panels, at least three times larger than any of the other panels, or at least four times larger than any of the other panels. The inlet

121 and outlet 122 are formed as spigots that protrude from the body 120 of the radiator 100. The inlet 121 is located on rear panel 143 and the outlet is located on the front panel 142. The inlet 121 is located to the left of the rear panel 143 and the outlet 122 is located to the right of the front panel 142. In other words, the inlet 121 and outlet

122 are located at opposite corners of the radiator 100.

The spigots of the inlet 121 and outlet 122 are integrally formed with the body 120. Integrally forming the spigots with the body helps to reduce the chance of leaks in the radiator when installed. However, it is envisaged that the spigots could be separately attached to the inlet 121 and outlet 122, for example through a screw thread connection or through welding on site etc.

Referring to Figures 4B and 4C, the radiator 100 can be completely hollow (Figure 4B) or the radiator 100 can have internal dividers 125 that form a series of channels 132, 133, 134 for the heating water to flow through (Figure 4C). The plurality of channels form the passage 130. The channels 132, 133, 134 are formed internally of the body by the dividers 125. The channels 132, 133, 134 are substantially parallel to each other. The internal dividers 125 ensure that the heating fluid comes into contact with a substantial portion of the top and bottom panels 140, 141 of the radiator 100. In addition, the internal dividers 125 increase the length of the passage 130. By providing greater contact with the top and bottom panels 140, 141 , and by increasing the amount of time the heating fluid is in contact with the top and bottom panels 140, 141 (due to the increase length of the passage 130), the heat transfer from the heating fluid through the body 120 to an exterior 124 of the body 120 can be increased.

The body 120 of the radiator 100 in Figures 4A to 4C is formed as a single unit to help reduce the chance of leaks in the heating system. The body 120 can be made as a single unit through techniques such as rotary moulding or vacuum forming. In other words, the body 120 is moulded with the passage 130. The radiator is made from a plastics material. Using a plastics material avoids corrosion that can occur in metal devices (depending on the heating fluid), which can result in leaking. Depending on the environmental conditions the radiator can be made from various plastics materials. In cooler environmental conditions the heating fluid needs to be hotter than the heating fluid used in warmer environments. Typically the temperature of the water through the radiator will be 5 to 45 degree Celsius above the ambient temperature, preferably 10 to 15 degree Celsius above the ambient temperature. For example, the radiator 100 could be made from acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PCV), polybutylene, high-density polyethylene (HDPE), polyethylene (PE) or any other suitable material. The heating fluid is ideally kept below 60 degrees Celsius as the concrete shell of the pool could potentially crack if this temperature is exceeded. The radiator 100 is formed with thin walls to aid in heat transfer. The wall thickness of the body is less than approximately 1.7mm, preferably less than 1.3mm, and more preferably less than 1 mm. A unitary, substantially rigid construction, as opposed to joining together numerous components on-site, heavily reduces the chance of leakage as there are fewer connections that can fail/leak. Reducing the likelihood of leakage is advantageous in the pool construction industry as a leak in the concrete slab can damage the slab and cause it to crack, requiring significant and expensive repair. It will be understood that using vacuum forming to create two corresponding halves, and connecting the two vacuum formed halves together in a factory through a permanent joining technique such as welding, constitutes forming a single unit. It is noted that the embodiment shown in Figure 4B has the advantage of being simple to make. The radiator can be designed to be any size desired. For example, the radiator 100 may have maximum dimensions (or the equivalent area of the largest surface, e.g. top 104 of radiator 100) of 3000mm x 3000mm, 2000mm x 2000mm, 2000mm x 1000mm, 1500mm x 1500mm or 1000mm x 1000mm. The radiator may have a minimum area equivalent to the area of dimensions of 500mm x 500mm, or 800mm x 800mm.

The radiator 100 may also be designed so that is can be easily transported using standard transportation methods. The radiator can be sized so that it will fit onto a standard pallet. As pallet sizes vary country to country the maximum size of the radiator will depend on the market in which the radiator is distributed. For example, the radiator 100 may have maximum dimensions of approximately 1 150mm x 1150mm, maximum dimensions of approximately 1000mm x 1200mm, maximum dimensions of approximately 1050mm x 1050mm, maximum dimensions of approximately 1 100mm x 1 100mm, maximum dimensions of approximately 800mm x 1200mm, maximum dimensions of approximately 1000mm x 1000mm, maximum dimensions of approximately 800mm x 1000mm. Referring to Figure 4D, two or more radiators 100 can be interconnected in fluid communication in series to increase the heat transfer required to keep the pool water at a desired temperature. The outlet 122 of a first radiator 100 is connected to the inlet 121 of a second radiator 100a. The radiators can be connected together by any suitable piping, for example PEX or ABS tubing 101.

A method of building a concrete pool shell 95 with a radiator 100 includes:

• installing reinforcing bar 96 and a radiator 100 in a base and/or sides of a pre- prepared pool pit (not shown);

• applying concrete to the base and sides of the pool pit and embedding the reinforcing bar 96 and the radiator 100 in concrete;

• drying the concrete to form a pool shell installed with the radiator.

During installation concrete is laid to cover the radiator and fully encase the radiator 100 in the base of the pool shell 95.

For simplicity the radiator is installed in a base of the concrete pool shell 95.

Connecting pipework (not shown) is attached to the inlet 121 and the outlet 122 of the radiator 100 before installing the concrete. The pipework leads to an exterior of the pool pit. The pipework forms part of the closed heating loop. The pipework from the heat source 60 to the radiator 100 is insulated to reduce the heat loss between the heat source 60 and the radiation 100, to ensure maximum heat transfer through the radiator 100. The return pipework from the radiator to the heat source is insulated to reduce the heat loss between the radiation 100 and the heat source 60, to reduce heat loss and thereby reduce the load on the heat source and increase the efficiency of the closed loop. The heat source can be a boiler, a heat pump, or any other suitable heat source.

A benefit of the radiator 100 is its simplicity. The standard pool installation steps remain the same, but with the addition of installing the radiator 100. There is no need for a vastly different installation process. In addition, no new equipment is required on site and the tools required to connect the radiator with the connecting pipework are tools commonly used in pool construction. The radiator 100 can also be installed with any other pre-fabricated pool shell, such as a fibreglass shell or a pre-fabricated concrete shell. A method of building a pool shell with a radiator includes:

· positioning a radiator 100 adjacent to a pool shell; and

• installing insulation 50 to cover an exterior of the pool shell 91 and the radiator 100 to insulate the exterior of the pool shell 91 and couple the radiator 100 to the exterior of the pool shell. In a similar way to the concrete pool shell 95, the radiator 100 can be located at the base of the pool shell and/or a side wall of the pool shell. The radiator 100 can be located adjacent to a fibreglass pool shell 91. As described above, connecting pipework is attached an inlet 121 and an outlet 122 of the radiator 100. Referring to Figure 6A, an alternative embodiment of a radiator 200 is shown. The radiator 200 has a substantially rigid and planar body 220 having a fluid inlet 221 and a fluid outlet 222. The body 220 has a passage 230 connecting the fluid inlet 221 to the fluid outlet 222. The body 220 transfers heat from fluid in the passage 230 through the body 220 to an exterior 224 of the body 220. The passage 230 has a first channel 231 and a second channel 232 defined by the body. The first channel 231 is substantially perpendicular to the second channel 232. As shown in Figure 6, the radiator has a plurality of first channels 231 , 233, 235, 237, 239 and second channels 232, 234, 236, 238, 240 that form a body 220 having a waffle-type structure with through-openings 229 between the channels. The plurality of first and second channels form a plurality of passages. The channels 231 , 233 are approximately 100mm to 150mm apart centre- to-centre. The channels are approximately 125mm centre-to-centre apart.

The radiator 200 is formed as a single unit, for example through rotary moulding or vacuum forming (as described above in relation to radiator 100). The radiator can have multiple inputs and multiple outputs, in order to provide more even flow of water through the radiator, and thereby more even heat transfer. As shown in Figure 6B, the radiator has a single input, shown as spigot 221 , and three outputs, shown as spigots 222, 223, 224. The internal diameters of the spigots can be identical, or the internal diameters can differ to encourage flow towards outputs that are on a more resistive pathway. The outer diameter of the spigots can either be constant to allow the same diameter connecting pipes for all spigots (i.e. the wall thickness of the spigots are different) or the spigots can all have the same wall thickness (i.e. the outer diameter of the spigots are different). By providing multiple outputs it is possible to reduce the likelihood of the majority of the heated fluid consistently taking a single path through the radiator 200. It is envisaged that the radiators 10a, 10b, 10c, 100 discussed above could also have multiple inlets and outlets. It is also envisaged that unused

inlets/outlets could be capped, thereby allowing a single multi-port radiator to be produced that allows the end user to determine how many inputs and outputs they require at the time of installation.

Referring to Figures 7 A to 7C, the cross section of the channels can be any suitable shape. Figure 7 A shows a first channel 231 with a substantially circular cross-section, Figure 7B shows a first channel 231 with a substantially square cross-section and Figure 7C shows a first channel 231 with a square cross-section rotated 45 degrees (i.e. a diamond cross section). In other words, Figure 7B and 7C show the first channel having a non-circular cross section. A non-circular cross-section provides more surface area for a given volume of fluid in the channel, thereby increasing the heat transfer from the heating fluid to the exterior of the radiator. In addition, using a diamond cross- section directs more heat away from the radiator as heat is not directed towards adjacent channels (as would occur with a square cross section - see Figure 7D). It will be understood that the diamond cross-section is a square cross-section in which the square has no surfaces that are parallel to the plane defined by the planar structure of the radiator. It is envisaged that other cross-sectional shapes could also be used, for example the channels could be semicircular, having the flat side up.

Referring to Figure 8, an alternative embodiment of a radiator 300 is shown. The radiator 300 has a first manifold 327 and a second manifold 328 that are part of a substantially rigid and planar body 320. The first manifold 327 has a fluid inlet 321 and the second manifold 328 has a fluid outlet 322. The first manifold 327 has five outlets 350, 351 , 352, 353, 354 that are connected to corresponding inlets 360, 361 , 362, 363, 364 on the second manifold 328 by pipes 340 to form the body 320 of the radiator 300. The body 320 transfers heat from fluid in the passage 330 through the body 320 to an exterior 324 of the body 320. The pipes 340 defines channels with through-openings 329 between the channels. The first and second manifolds can be made from the same materials as described above relating to the radiator 100 and radiator 200. The pipes 340 can be made from any suitable material, for example PVC, ABS, PEX tubing etc.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.