AU2013202532A1 - Water saving apparatus - Google Patents

Abstract

Abstract: A water saving apparatus for use with a hot water system, the apparatus being sized and shaped for installation 5 proximate one or more water outlet fixtures for delivery of heated water from the hot water system for use. The apparatus comprises an insulated reservoir having an inlet and an outlet to enable the reservoir to be installed in line with the flow of heated water from the hot water 10 system to the one or more fixtures to store a quantity of heated water. Water that has cooled in the hot water pipe between the hot water system and the reservoir mixes with the stored heated water in the reservoir as water flows from the hot water system to the water outlet fixture. 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 Mains water supply 10 Heater water -* (cold) V Hot Water System Reservoir 1_ _ _ -160 < 170 195 / / /il I Figure 1

Description

- 1 WATER SAVING APPARATUS Technical Field 5 The field of the invention is water saving systems, methods and apparatus aiming to reduce water wasted in domestic use. Background 10 Increasing populations and climate change are causing ever increasing strains on water resources and drinking water supplies. In recent times this has resulted in water restrictions for households and businesses and increasing 15 prices. It is therefore desirable to conserve water resources and avoid waste. Particularly in domestic situations large volumes of water can be wasted during the simple act of washing using hot water and waiting for hot water supply, for example, showering or washing hands 20 under running water. Water saving systems have been developed to recover and reuse waste water, often referred to as to grey water systems. Where a grey water system is installed, all 25 water used for washing can be recovered in the grey water system, including the clean water that goes down the drain while waiting for hot water. Some grey water systems perform some treatment of the waste water and others simply store the waste water for a secondary use. Due to 30 health concerns restrictions are generally imposed on the use of grey water, for example limiting use to flushing of toilets, watering of gardens and maybe for laundry use. Installation and use may also be restricted to ensure that grey water will not enter storm water drains. Grey water 35 systems can be expensive and complex to install; requiring significant space for a large grey water storage tank and pump and significant re-plumbing for effective collection 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 2 and reuse of recycled water. Ongoing maintenance is also required, for example regular changing of filters and servicing of pumps. 5 Other systems have been devised to recover fresh water that would otherwise be wasted before this goes down the drain to be treated as waste water. Known systems utilize temperature sensitive valves in hot water pipes to divert water from hot water pipes until the water reaches a 10 threshold temperature. The diverted water is diverted to a holding tank. The water from the holding tank can then either be redirected into cold water supply pipes or used for another purpose such as watering gardens or flushing of toilets, similar to grey water use. Such systems 15 recover water before it is released from the tap for diversion into the cold water circulation or another purpose and thus require significant re-plumbing for installation. Further because these systems use temperature sensing valves they may require regular 20 maintenance. There is a need for simpler low maintenance systems to reduce wasting water. Summary of the Invention 25 Aspects of the present invention provide a water saving apparatus for use with a hot water system, the apparatus being sized and shaped for installation proximate one or more water outlet fixtures for delivery of heated water from the hot water system for use, the apparatus 30 comprising: an insulated reservoir having an inlet and an outlet; the inlet being arranged to be connectable to a hot water pipe which carries heated water from the hot water system and the outlet arranged to be connectable to a hot 35 water pipe providing heated water to the one or more water outlet fixtures to enable the reservoir to be installed in line with the flow of heated water from the hot water 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 3 system to the one or more fixtures to store a quantity of heated water whereby water that has cooled in the hot water pipe between the hot water system and the reservoir mixes with the stored heated water in the reservoir as 5 water flows from the hot water system to the water outlet fixture. In an embodiment at least the inlet can be provided with a one way valve arranged to allow water to flow into the 10 reservoir and inhibit reverse flow of water from the reservoir to the hot water pipe. The outlet may also be provided with a one way valve. In an embodiment the outlet is located in a lower portion 15 of the reservoir. The inlet may be located in any of an upper, central or lower portion of the reservoir. Alternatively, the outlet may be located in a central or upper portion of the reservoir and the inlet located in any one of an upper, central or lower portion of the 20 reservoir. In other embodiments the inlet and outlet may be located in the top and bottom of the reservoir or both located in the top or bottom of the reservoir. The apparatus can include baffles arranged to aid mixing 25 of water entering the reservoir via the inlet with water in the reservoir before release via through outlet. The baffles can be perforated. Brief Description of the Drawings 30 Figure 1 is a block diagram representing an application of an embodiment of the present invention; Figures 2 to 7 are block diagrams of various embodiments 35 of the present invention; and Figure 8 is a graph of an example of water temperature 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 -4 change in an embodiment. Detailed Description 5 Embodiments of the present invention provide a water saving apparatus for use with a hot water system. A block diagram of an embodiment is shown in Figure 1. The apparatus is sized and shaped for installation proximate one or more water outlet fixtures, such as shower heads 10 195 or faucets for delivery of heated water from the hot water system 120 for use and comprises an insulated reservoir 110having an inlet 160 and an outlet 170. The inlet 160 is arranged to be connectable to a hot water pipe 140 which carries heated water 150 from the hot water 15 system 120. The inlet 160 can be provided with a one way valve to enable water to flow in the direction from the hot water system 120 into the reservoir 110 only. The outlet 170 is arranged to be connectable to hot water pipe 180 providing heated water to the one or more water outlet 20 fixtures 195. This arrangement enables the reservoir 110 to be installed in line with the flow of heated water 150 from the hot water system 120 to the one or more fixtures 195 to hold, in the reservoir 110, a quantity of stored heated water proximate the one or more water outlet 25 fixtures 195 and provide heated water to the water outlet fixtures 195 via the reservoir 110. When one of the water outlet fixtures is operated to release heated water, then any water that has cooled in the hot water pipe 140 between the hot water system 120 and the reservoir 110 30 mixes with the stored heated water in the reservoir 110 as water flows from the hot water system 120 to the water outlet fixture 190. Thus reducing the waiting time for heated water, as cooled water from the pipe 140 is mixed with stored heated water in the reservoir 110, rather than 35 a user needing to wait for the cooled water to be purged from the pipe 140, and typically run down the drain, before heated water is provided. 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 5 The reservoir 110 vessel may be constructed of any suitable material, for example stainless steel, copper, fibreglass or plastic. Composite materials may also be 5 used to construct the reservoir. The vessel is insulated to aid heat retention in the stored water. In an embodiment the vessel may be insulated by providing an outer layer of insulation. Alternatively the vessel may have a double walled construction to provide an insulation 10 layer of air or insulating material between the walls. In another embodiment the reservoir vessel is contained within an insulated housing. It should be appreciated by a skilled person that any suitable material may be used. The reservoir vessel may take on a variety of forms with 15 its shape and volume varying based on requirements for different installations. For example, the vessel can be shaped to accommodate restrictions in installation of the reservoir proximate the water outlet fixture. For example, relatively tall and flat shapes may be used for 20 installation within a cavity wall or short squat shapes may be more suitable for location within a roof space. In embodiments for use with pressurised hot water systems the reservoir vessel will be formed appropriately to comply with the pressure requirements. For example, the vessel 25 may be cylindrically shaped to enable pressure requirements to be met. A cylindrical reservoir vessel may be housed within a reservoir casing of a different shape adapted for more easy handling and installation, for example oblong or box like. In such embodiments the inlet 30 and outlet of the reservoir vessel can be connected to inlet and outlet fittings that are accessible from the exterior of the casing to connect in line with the hot water pipe. The casing may be insulated in addition to or as an alternative to insulation of the reservoir vessel 35 itself. The casing may carry any appropriate brackets and fittings for handling and installation. The casing may also support accessories such as pressure release valves, 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 6 drainage/spill pan, drainage hose or fittings for holding such accessories. In alternative embodiments appropriate brackets and fittings may be provided on or attachable to the reservoir vessel directly. 5 It should be appreciated that any shape reservoir vessel may be used provided the appropriate pressure requirements can be met. The shape of the vessel may be influenced by the material used. For example it may be necessary for 10 the vessel to have a cylindrical shape to meet pressure requirements when constructed using aluminium. Alternative embodiments using different materials and/or structural features may have different shapes and still fulfil pressure requirements. For example, oblong shapes 15 may be used with appropriate materials and, if necessary, strengthening structures (such as ribs or internal lattices) of the reservoir vessel. Placement of inlet and outlet fittings for the reservoir vessel may also be influenced by the need to fulfil pressure requirements and 20 all possible variations are contemplated within the scope of the present invention. Embodiments of the reservoir may be configured for installation inside a wall or ceiling cavity so the 25 reservoir is hidden from view. Alternative embodiments may be configured to be installed in a manner where the reservoir is visible, for example mounted on an interior wall above a shower or sink. Embodiments configured for visible installation may have an exterior reservoir 30 housing shape and any accessories and fittings designed for aesthetics as well as function. The size of the reservoir may vary between embodiments. A minimum reservoir size for an installation may be selected 35 based on the length of pipe 140 between the hot water system and reservoir and therefore the maximum volume of cold water anticipated to be mixed with the contents of 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 7 the reservoir and provide heated water at a reasonable temperature at the water outlet fixture. Other considerations for choice of reservoir size can include anticipated use and space. (Examples will be discussed in 5 more detail in the following paragraphs.) As discussed in later examples, the reservoir may be constructed in a manner which aides the mixing of water within the reservoir. 10 The inlet and outlet of the reservoir can be provided with fittings that are adapted for connecting the inlet and outlet to standard hot water pipes. For example, the inlet and outlet fittings may be suitable for establishing water tight connections directly with either copper or 15 polyvinyl chloride (PVC) hot water piping. Alternatively the inlet and outlet may be connected to hot water pipes using adapters to accommodate differences is size between inlet and outlet fittings and hot water pipes. For example a reservoir may be provided with 20mm inlet and 20 outlet fittings and adapters used for connecting these fittings to 15mm water pipes. The reservoir input and output fixtures can be designed for minimal re-plumbing for installation. 25 In an embodiment, the inlet fitting 160 has a built in non-return check valve which allows water to flow into the reservoir from the hot water pipe but stops reverse flow. Any suitable non-return valve configuration may be used. It should be appreciated that in some embodiments the non 30 return valve may be a standard plumbing non-return valve which is a separate component from the inlet fitting 160 that is connectable to the inlet fitting 160. The output fitting 170 may also be provided with a one way check valve. The one way valves on the inlet and outlet can be 35 optional. The reservoir 110 is connected, using the inlet 160 and 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 8 outlet 170 fittings, to be in line with the flow of water from the hot water system to the water outlet fixture such that cooled water in the pipe 140 will mix with heated stored water in the reservoir as the hot tap 190 is open 5 to draw off water by the pipe 180. When the hot tap 190 is closed, heated water will be held in the insulated reservoir 110. Use of a one way valve on the inlet 160 inhibits exchange of water from the reservoir with water cooling in the water supply pipe 140 while water is not 10 flowing, thus aiding heat retention. The one way check valve in the inlet 160 can also be configured to aid heat retention by reducing heat transfer between the water stored in the reservoir and water cooling in the pipe 140. Further, most hot water systems are pressurised (mains 15 pressure hot water systems) and this pressurisation can also aid heat retention in the reservoir. Pipes 140 used to deliver water from a hot water system storage tank 120 to water outlet fixtures such as taps and 20 faucets are typically not insulated to minimize cost. In installations where the hot water system storage tank 120 is some distance away from the heated water outlet fixture, say a shower 195, the pipe 140 may hold a significant quantity of water which will cool while 25 sitting in the pipe 140. A person having a shower will typically let cooled water run down the drain and be wasted while waiting for water hot enough to shower with. The distance between a hot water tank 120 and a shower 30 outlet 195 in a bathroom may vary from a few meters to over 25 meters depending on the design of the house and location of the hot water system 120. Particularly where a single hot water system is used to provide water for more than one bathroom, or wet areas such as kitchen and 35 laundry are not located near the bathroom, the hot water system may be a considerable distance from a shower outlet in at least one bathroom. It is common for at least 8-12 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 9 meters of pipe to be between a hot water system and shower in an average home, this represents around 3-71 of water depending on the size of the pipe 140. This water will typically be wasted at least once every day representing a 5 waste of around 1100 to 2555 litres per year. However, this figure will vary from household to household depending on a number of factors, such as the number of bathrooms, time between showers, length and diameter of piping between the hot water system and showers, and 10 piping material. Using the system of the present invention the amount of waste water for a household can be significantly reduced. An example of the operation of an embodiment of the 15 invention will now be discussed in more detail with reference to Figure 1. In this example, the reservoir 110 is installed upstream of a shower 195 and its respective tap 190 in a roof cavity as close as practical to the hot tap 190. The reservoir 110 is installed as close as 20 practical to the hot tap 190 to minimize the length of pipe 180 between the reservoir and the hot tap. The hot water system 120 receives cold water via the main supply 130 and heats this water. The temperature of the hot water system 120 is typically set by the householder using 25 a thermostat, so the temperature can vary, for example householders will typically set the thermostat for their hot water service somewhere between 60'C and 80*C. Australian building codes regulate the temperature for hot water supplied to bathrooms to 55 0 C in new buildings. In 30 such cases the hot water system 120 will have a mix down mechanism to mix hot water output from the heating tank with cold water to reduce the temperature to around 55'C as the water is supplied to the bathroom hot water supply pipe 140. (The mix down mechanism is not shown in the 35 simple block diagram of Figure 1). In buildings constructed prior to introduction of bathroom temperature regulations the water supplied to the pipe 140 may be 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 10 hotter as no mix down is required. For this example we will consider the heated water 150 is supplied to pipe 140 at a temperature of 55 0 C. 5 Operation of the hot tap 190 draws water from the reservoir 110 via the pipe 180 which, in turn, causes heated water 150 to flow from the hot water system 120 via the pipe 140 toward the reservoir 110. As water is drawn off from the reservoir 110 via the pipe 180 initially, the 10 water entering the reservoir 110 from pipe 140 will be water that has cooled sitting in the pipe 140 since the shower was last operated. Within the reservoir 110 this cooled water mixes with the stored water in the reservoir before being drawn off from the outlet 170. 15 The only cold water the user may experience is a small amount of water from the pipe 180 between hot tap 190 and the outlet 170 which may be barely perceptible to the user so it appears that the heated water is supplied 20 instantaneously. Initially, the water from the pipe 140 being mixed with the water in the reservoir 110 is cooled from sitting in the pipe so the temperature of the water in the reservoir 25 will drop as a result of this mixing. As the pipe 140 is flushed of cooled water by freshly heated water 150 the temperature of the water being mixed in the reservoir 110 will increase. This decrease and increase in water temperature will be gradual by virtue of the mixing and 30 thus a shock of rapidly going from very cold to very hot water is avoided. This can be unpleasant and also dangerous, particularly for children or elderly persons with delicate easily scalded skin. 35 Typical flow rate of a shower is 9 litres per minute which is generally a mix of cold water and hot water, depending on the length of the hot water piping 140 from the main 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 11 hot water system the amount of cold water entering the reservoir will vary. Considering a scenario of around to 5 to 7 litres of cooled water sitting in the pipe 140 it should be appreciated, that without having heated water 5 stored in the reservoir approximate the shower 195 a person would have waited for around a minute with fresh water running down the drain before having hot water to shower with. Using an embodiment of the present invention heated water is provided at the shower 195 almost 10 instantaneously even though it may take 1 to 2 minutes before the 5-7 litres of cooled water is flushed from the pipe 140 and fresh hot water arrives at the reservoir 110. After the cooled water is flushed from the pipe 140 the water in the reservoir 110 is refreshed with freshly 15 heated water 150 flowing from the hot water system 120. The minimum water temperature (Tmn) due to mixing of water from the pipe 140 with water stored in the reservoir 110 can be estimated using equation 1 below 20 (Vp XTprnj.) + ((VR - Vp)XTRmi.) _1 VR min [Equation 1] Where Vp is the volume of water in the pipe 25 Tpmin is the temperature the water in the pipe has cooled to VR is the volume of water in the reservoir

TR

1 n is the temperature the volume of water in the reservoir has cooled to 30 In an example of an embodiment for use with a hot water supply of 55'C the reservoir has a capacity of around 45 litres and cools to around 50*C after 24 hours. Where 7 litres of water is held in the pipe 140 and has cooled to 35 around 15*C, using Equation 1, the minimum temperature of water supplied from the reservoir Tmn is around 44.5'C. It should be appreciated that the minimum temperature 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 12 calculation can only be an approximation as this calculation assumes that the entire volume of cooled water replaces water from the reservoir. Whereas in practice, by virtue of mixing of water in the reservoir, water being 5 drawn from the reservoir will be a mix of water from the reservoir 110 and pipe 140. Further, even if the water temperature approaches the calculated minimum temperature the water temperature does not remain at this temperature due to hot water arriving via the pipe 140 and mixing in 10 the reservoir. Figure 8 shows an example of varying temperature in the reservoir over time based on the above example. Time A represents the time a person turns on the shower with the 15 water in the reservoir at a temperature of 50*C. Between time A and time B cooled water from the pipe 140, at around 15*C, is mixing with water in the reservoir as water is drawn off from the reservoir. Time B represent the time when all the cooled water is flushed from the pipe 20 140 and fresh hot water, at a temperature of 55'C, arrives at the reservoir 110. Between time B and time C mixing of the fresh hot water with the water in the reservoir causes the temperature in the reservoir to rise until all the water previously stored in the reservoir has been replaced 25 with fresh hot water and the temperature of the reservoir reaches the maximum of 55*C. From time C the person continues showering with the water at a constant temperature of 55'C until turning off the shower at time D. After time D water stored in the reservoir will cool until 30 the shower is next used, however the rate of cooling of water in the reservoir is much slower than for water in the pipe. It should be appreciated that the minimum temperature in this example represents a worst case scenario and in practice the temperature may not drop to 35 this minimum. For example, depending on the design of the house and plumbing system, water from the pipe 140 may be drawn off upstream of the reservoir 110 at other outlets 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 13 (say a kitchen or laundry) in between use of the shower, causing heated water to be refreshed in at least part of the pipe 140, reducing the volume of cooled water and/or increasing the temperature of the cooled water mixing in 5 the reservoir 110. The rate of cooling of the water in the pipe 140 is also dependent on many variables, such as the diameter of the pipe, material of the pipe (for example PVC or copper), length of pipe, location of pipe within the building an any insulating effect or lack 10 thereof, and environmental factors such as ambient temperatures. Some of these variables are also pertinent to the rate of heat loss from the reservoir, in particular environmental factors and location of the reservoir, as well as the volume, shape, and insulating properties of 15 the reservoir vessel. Further, factors such as water pressure, pipe diameter and flow rate will also affect the time taken for fresh hot water to reach the reservoir. The reservoir size is chosen in this embodiment by 20 estimating that this volume of water can be retained in the insulated reservoir 110 at a temperature suitable for showering for at least 48 hours and up to 72 hours. It should be appreciated that the thermal mass of the water stored in the reservoir in combination with the insulation 25 serves to retain heat in this stored water, whereas the water sitting in the uninsulated pipe 140 will rapidly cool. While water is held in the reservoir 110 it will slowly cool and the rate at which the stored water will cool will vary depending on insulation, size and shape of 30 the reservoir vessel. People typically shower at temperatures between 28'C and 32'C so even if the water in the reservoir does cool by around 15'C to around 40'C the temperature will still be 35 more than adequate for comfortable showering. Typically, showers are utilized every 12 to 24 hours, sometimes more frequently, so cooling of the water in the reservoir may 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 14 not even be perceptible to the users. Selection of reservoir size based on cooling over a 72 hour period is suggested to allow for cooling over a long weekend absence. If the reservoir is allowed to cool over a 5 longer period the stored water may be too cold to be used comfortably and in such cases some of the stored water may be wasted. However, it is anticipated that this would be infrequent. Further, not all water in the reservoir would need to be flushed and replaced as hot water from the pipe 10 mixes with cooled water in the reservoir to raise the temperature to a comfortable temperature for showering (between 28'C and 32'C) before all water in the reservoir is replaced. 15 Embodiments of the invention are particularly suited for use with showers because of the typical temperatures and length of time that the hot water is typically flowing. For example what is considered a very short shower is around 3 to 4 minutes but most people prefer to take 20 longer and often households have more than 1 person showering soon after one another. In such situations the reservoir may be completely replenished with freshly heated water during these showers. Even mixing of around 5 to 7 litres of cold water say at around 15'C with water 25 at around 40'C in the reservoir 110 would result in water above the standard shower operating temperature around 28'C to 32'C. Mixing of water within the reservoir 110 may be aided by 30 the geometry of the reservoir and location of the inlet and outlet, some examples will be discussed with reference to Figures 2 to 4. In the example of Figure 2a, the reservoir 110 is relatively squat and the inlet 160 and outlet 170 are both located in a lower portion of the 35 reservoir, on opposite sides and water is mixed by virtue of movement of the water through the reservoir from one side to the other and convection. Alternatively the inlet 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 15 an outlet may be located in the top and bottom of the reservoir. Locating the outlet in the lower portion of the reservoir enables the reservoir to be easily drained empty, if necessary. However, other locations of the 5 outlet are envisaged for example in a central or upper portion of the reservoir. The reservoir may be provided with a secondary outlet for draining, if necessary. For example, in the embodiment shown in figure 2b the inlet and outlet are both located in an upper portion of the 10 reservoir on opposite sides. Location of the outlet in the upper portion of the reservoir can be advantageous as, when the water is still, thermal convection will result in the warmer water being in upper portion of the reservoir and therefore this warmer water will be first drawn off 15 from the reservoir. Thermal convection will cause cooled water entering the reservoir from the pipe 140 to move toward the lower portion of the reservoir and urge warmer water toward the upper portion causing a mixing action which in turn will aid mixing of heated water with water 20 in the reservoir as water is drawn off. Similarly one or both of the inlet and outlet may be located in a central portion of the reservoir and mixing occurs by virtue of thermal convention and current created by the ingress and egress of water. Embodiments are envisaged where the same 25 reservoir can be installed using different orientations, for example in a upright position the inlet and outlet can be in lower part of the reservoir or in an upside down installation the inlet and outlet are in an upper portion of the reservoir. 30 In the example of Figure 3 the inlet 160 is located in an upper portion of the reservoir 110 and the outlet 170 is located in a lower portion of the reservoir. In this example, mixing of water is again aided by the flow of 35 water through the reservoir and convection. In this example, cold water entering the top of the reservoir 110 via the inlet 160 will be caused by convection to move 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 16 down through the reservoir to mix with the warmer water before exiting through the outlet 170. Once the water supplied by the inlet 160 is warmer than the water within the reservoir the effect of natural convection results in 5 the warmer water remaining above the cooler water in the reservoir, so the cooler water is released via the outlet 170 and gradually replaced with the warmer water entering the top of the reservoir via the inlet 160. 10 Figure 4 shows an example similar to that of Figure 3 which utilises natural convection and movement of the water through the reservoir for mixing, however in this embodiment the inlet 160 is located in the central portion of the reservoir 110. The inlet may also be located in a 15 lower portion of the reservoir. In these examples the outlet is shown in a lower portion of the reservoir but embodiments where the outlet is in a central or upper portion are also envisaged. Irrespective of location of inlet and outlet the temperature of the water in the 20 reservoir equalises as water flows through the reservoir due to the combined effects of currents in the flowing water, pressurisation of the hot water system and thermal convention. 25 Mixing of water within the reservoir may be aided by the shape of the reservoir vessel itself or internal features within the reservoir vessel. In some embodiments, baffles may be provided within the reservoir 110 to aid mixing of water within the reservoir 110 the baffles are designed to 30 channel the water through the reservoir to aid mixing and can also be arranged to aid flow of water through the reservoir to flush previously stored water from the reservoir as it is replenished with freshly heated water that it is at the optimum temperature. Some non limiting 35 examples of use of baffles are shown in Figures 5 to 7. Figure 5 shows an example of a reservoir 110 having four internal horizontal baffles to aid mixing of water stored 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 17 in the reservoir 110 with water supplied via the inlet 160 as it travels through the reservoir to the outlet 170. The baffles 510 may be solid or perforated depending on the embodiment. 5 In the example of Figure 6a, the inlet 160 and outlet 170 are both located in the base of the reservoir 110 and a baffle 610 is located between the inlet 160 and outlet 170 to force mixing of the water from the inlet 160 with water 10 in the reservoir 110 before discharge via the outlet 170. This embodiment may be suitable in an application where there is little space for rerouting of pipes or to simplify installation. It should be appreciated that in this example pipes 140 and 180 may initially have been a 15 single hot water supply pipe that has had a section removed and replaced with elbow pieces or stops 620,625 and 630,635 connected to the respective portions of the hot water pipe to divert the flow of hot water via the reservoir 110. Similarly the inlet and outlet may be 20 located in the top of the reservoir, or towards the top of the reservoir with a baffle therebetween to aid mixing of the water in the reservoir. For example, Figure 6b shows an embodiment where both the inlet and outlet are located in the top of the reservoir. Pressurisation of the hot 25 water system enables water to be drawn off the outlet as water flows into the reservoir in this example. The baffles need not be symmetrically arranged within the reservoir, as shown in the example of Figure 7, baffles 30 710 can be arranged in any configuration suitable for encouraging a mixing flow of water from the inlet 160 to the outlet 170. It should be appreciated that any shape orientation or arrangement of baffles is contemplated within the scope of the present invention. It should be 35 appreciated that baffle arrangements may vary with the volume and geometry of the reservoir and the construction of the baffles themselves, for example different size and 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 18 shape of perforations. Any arrangement of inlet and outlet position and baffle configuration is envisaged within the scope of the present 5 invention. Other internal structures of the reservoir vessel such as ridges, ribs, waves, contours, waffling or texturing of internal reservoir surfaces may also be used to aid mixing and all such alternatives are considered within the scope of the present invention. 10 In some embodiments baffles may take the form of internal lattices, ribs or other structure which provide a combined effect of strengthening the reservoir vessel and aiding mixing of water in the reservoir. For example a lattice 15 of interconnected members which add strength to the reservoir vessel may also be arranged to direct flow of water through the reservoir between the inlet and the outlet in a manner that aids mixing, for example a helical structure. In another example baffles for aiding mixing of 20 water may also act as strengthening ribs for the reservoir vessel. All such variations are contemplated within the scope of embodiments of the present invention. Embodiments of the present invention may be installed with 25 existing hot water systems in a manner that requires minimal re-plumbing and no modification to the existing hot water system. The volume and geometry of the reservoir 110 may be selected based on the distance from the main hot water supply tank and space available for the 30 reservoir. Thus, many different shapes and sizes of reservoirs may be provided. The examples given above and in the accompanying drawings are non limiting illustrative examples. 35 Additional features of the reservoir may include pressure release valves, draining/spill pans and additional outlets for draining. Inclusion of such additional features may 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 19 be mandated in some areas by building codes or regulations. In other areas these may be optional features. Any combination of such optional features is envisaged within the scope of the present invention. 5 Embodiments of this water saving apparatus are passive requiring no sensors or electronic components for operation. It should therefore be appreciated that minimal or no maintenance is required and there is no 10 standby running cost. A further advantage of the use of this invention is an effective increase in hot water storage as heated water is now stored both in the tank of the hot water system 120 and the reservoir 110. Typically, it takes a hot water system 120 some time to 15 heat a full tank and it is possible for the heated water of the hot water system 120 to be exhausted during a period of high use, for example, in larger households or if guests increase the number of people showering. 20 The above examples all describe using the invention in conjunction with showers as this is a highly suitable and preferred application. However the invention may also be used in other applications such as sinks or in laundries. 25 It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention. It is to be understood that, if any prior art publication 30 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. 35 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 4169912_5 (GHMatters) P92625.AU.1 04/04/2013 - 20 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 5 features in various embodiments of the invention. 4169912_5 (GHMatters) P92625.AU.1 04/04/2013

Claims (5)

1. A water saving apparatus for use with a hot water system, the apparatus being sized and shaped for 5 installation proximate one or more water outlet fixtures for delivery of heated water from the hot water system for use, the apparatus comprising: an insulated reservoir having an inlet and an outlet; the inlet being arranged to be connectable to a hot 10 water pipe which carries heated water from the hot water system and the outlet arranged to be connectable to a hot water pipe providing heated water to the one or more water outlet fixtures to enable the reservoir to be installed in line with the flow of heated water from the hot water 15 system to the one or more fixtures to store a quantity of heated water whereby water that has cooled in the hot water pipe between the hot water system and the reservoir mixes with the stored heated water in the reservoir as water flows from the hot water system to the water outlet 20 fixture.

2. The apparatus as claimed in claim 1 wherein and at least the inlet has a one way valve arranged to allow water to flow into the reservoir and inhibit reverse flow 25 of water from the reservoir to the hot water pipe.

3. The apparatus as claimed in claim 1 or claim 2 wherein the outlet is located in a lower portion of the reservoir. 30

4. The apparatus as claimed in any one of the preceding claims further comprising baffles arranged to aid mixing of water entering the reservoir via the inlet with water in the reservoir before release via through outlet. 35

5. The apparatus as claimed in claim 4 wherein the baffles are perforated. 4169912_5 (GHMatters) P92625.AU.1 04/04/2013