WO2014121335A1 - Water saving apparatus - Google Patents
Water saving apparatus Download PDFInfo
- Publication number
- WO2014121335A1 WO2014121335A1 PCT/AU2014/000093 AU2014000093W WO2014121335A1 WO 2014121335 A1 WO2014121335 A1 WO 2014121335A1 AU 2014000093 W AU2014000093 W AU 2014000093W WO 2014121335 A1 WO2014121335 A1 WO 2014121335A1
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- WO
- WIPO (PCT)
- Prior art keywords
- water
- reservoir
- outlet
- inlet
- hot water
- Prior art date
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E03—WATER SUPPLY; SEWERAGE
- E03B—INSTALLATIONS OR METHODS FOR OBTAINING, COLLECTING, OR DISTRIBUTING WATER
- E03B7/00—Water main or service pipe systems
- E03B7/04—Domestic or like local pipe systems
- E03B7/045—Domestic or like local pipe systems diverting initially cold water in warm water supply
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D17/00—Domestic hot-water supply systems
- F24D17/0026—Domestic hot-water supply systems with conventional heating means
- F24D17/0031—Domestic hot-water supply systems with conventional heating means with accumulation of the heated water
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D17/00—Domestic hot-water supply systems
- F24D17/0089—Additional heating means, e.g. electric heated buffer tanks or electric continuous flow heaters, located close to the consumer, e.g. directly before the water taps in bathrooms, in domestic hot water lines
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/40—Protecting water resources
- Y02A20/411—Water saving techniques at user level
Definitions
- the field of the invention is water saving systems, methods and apparatus aiming to reduce water wasted in domestic use.
- 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 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 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 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 and reuse of recycled water. Ongoing maintenance is also required, for example regular changing of filters and servicing of pumps.
- 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 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 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 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 fixture.
- At least the inlet can be provided with a one way valve arranged to allow water to flow into the 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.
- the outlet is located in a lower portion of the reservoir.
- the inlet may be located in any of an upper, central or lower portion of the reservoir.
- 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 reservoir.
- 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 one or more structures arranged inside the reservoir to aid mixing of water entering the reservoir via the inlet with water in the reservoir before release via through outlet.
- at least one of the one or more structures is a fluid distributor connected to the inlet to allow fluid to flow therethrough and configured to control entry of water from the inlet into the reservoir.
- the fluid distributor is configured to enable some heat exchange between the water flowing therethrough and the water in the reservoir before the water entering the reservoir mixes with the water in the reservoir.
- the fluid distributor is configured such that water flowing therethrough enters the reservoir remote from the outlet.
- the fluid distributor is configured to disperse the inflowing water throughout the reservoir.
- the fluid distributor comprises a body for water to travel therethrough, the body having a plurality of apertures to allow water to be released into the reservoir.
- the body is an elongate pipe with apertures distributed along the length of the pipe. The apertures can be distributed asymmetrically along the length of the pipe. Alternatively the apertures may be evenly distributed.
- the fluid distributor comprises a plurality of interconnected pipes.
- the apparatus can include baffles arranged to aid mixing of water entering the reservoir via the inlet with water in the reservoir before release via through outlet.
- the baffles can be perforated.
- the inlet and outlet are provided with insulated connecting fixtures to reduce heat loss from the reservoir.
- the inlet and outlet are provided with dual component fittings, each comprising a proximate component for respective connection to the reservoir, and a distal component for connection to the respective hot water pipe or water output pipe, the connection between the proximate and distal components of the fittings being insulated and configured to inhibit water flow between the reservoir and external pipes in the absence of water flow from the water outlet fixture.
- 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 of the present invention.
- Figure 8 is a graph of an example of water temperature change in an embodiment
- FIGS 9 to 12 are block diagrams of further embodiments of the present invention.
- Figure 13 is an example of an embodiment of the invention.
- Figures 14a and 14b show a first example of a fluid flow model and fluid distributor
- Figures 15a and 15b show a second example of a fluid flow model and fluid distributor
- Figures 16a and 16b show a third example of a fluid flow model and fluid distributor
- Figure 17 shows comparative temperature profiles for an embodiment of the present invention and standard hot water supply configuration
- Figure 18 shows comparative temperature profiles for different installation conditions and cooling times for an embodiment of the present invention.
- 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 195 or faucets for delivery of heated water from the hot water system 120 for use, and comprises an insulated reservoir 1 10 having 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 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 1 10 only.
- the outlet 170 is arranged to be connectable to hot water pipe 180 providing heated water to the one or more water outlet 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 fixtures 195 and provide heated water to the water outlet fixtures 195 via the reservoir 1 10.
- any water that has cooled in the hot water pipe 140 between the hot water system 120 and the reservoir 110 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.
- the reservoir 110 vessel may be constructed of any suitable material, for example stainless steel, copper, fibreglass or plastic. Composite materials may also be used to construct the reservoir.
- the vessel is insulated to aid heat retention in the stored water.
- the vessel may be insulated by providing an outer layer of insulation.
- the vessel may have a double walled construction to provide vacuum insulation, an insulation layer of air or other gas (for example argon, nitrogen or mixed gases having heat insulating properties) or insulating material between the walls. Different materials may be used for internal and external walls of a double walled vessel. Alternatively, multiple layers of different materials may be used for insulating the reservoir.
- 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 its shape and volume varying based on requirements for different installations.
- the vessel can be shaped to accommodate restrictions in installation of the reservoir proximate the water outlet fixture.
- relatively tall and flat shapes may be used for installation within a cavity wall or short squat shapes may be more suitable for location within a roof space.
- the reservoir vessel will be formed appropriately to comply with the pressure requirements.
- the vessel 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.
- the inlet and outlet of the reservoir vessel inlet and outlet 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.
- Some embodiments may use inlet and outlet fittings for the reservoir that are internal to the casing, and may also be insulated within the casing, which are connected to externally accessible inlet and outlet fittings on the casing.
- the casing may be insulated in addition to or as an alternative to insulation of the reservoir vessel 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, drainage/spill pan, drainage hose or fittings for holding such accessories.
- appropriate brackets and fittings may be provided on or attachable to the reservoir vessel directly.
- 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 the vessel to have a cylindrical shape to meet pressure requirements when constructed using lightweight aluminium or plastics materials and for cost effective construction.
- Placement of inlet and outlet fittings for the reservoir vessel may also be influenced by the need to fulfil pressure requirements and 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 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 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 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 the reservoir and provide heated water at a reasonable temperature at the water outlet fixture.
- the reservoir volume may be chosen based on requirements for maintaining biological safety of the stored water given the local conditions. Water stored in a smaller vessel will typically be totally refreshed more regularly than a larger vessel and therefore the risk of bacteria growing to unsafe levels will be lower for a smaller vessel.
- the actual maximum vessel size to minimise biological risk will vary based on many factors some of which include, level of biological contamination in original water supply, temperature the water is heated to initially, typical length of time water will be stored for the given installation, ambient temperature, type of insulation used etc.
- the maximum size of a passive hot water storage vessel may be mandated by local health regulations or building codes. For example, in Australia regulations for control of Legionnaires disease restrict the size of hot water storage vessels to 10 litres unless actively heated. Prototype testing has shown that a vessel of this size can provide highly effective results. Other considerations for choice of reservoir size can include anticipated use and space. (Examples will be discussed in more detail in the following paragraphs.) As discussed in later examples, the reservoir may also be constructed in a manner which aids the mixing of water within the reservoir.
- 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.
- the inlet and outlet fittings may be suitable for establishing water tight connections directly with either copper or polyvinyl chloride (PVC) hot water piping.
- PVC polyvinyl chloride
- the inlet and outlet may be connected to hot water pipes using adapters to
- a reservoir may be provided with 20mm inlet and 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.
- Inlet and outlet fitting may be constructed to minimise heat loss for the reservoir via the fittings.
- the fittings may be insulated, made using low heat conductivity materials, use internal valve structures, such as double walled valves, to minimise heat transfer between water on each side of the valve.
- Any suitable fitting material or structure may be used and all variations are considered within the scope of the present invention.
- 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-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 optional.
- the reservoir 1 10 is connected, using the inlet 160 and 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 to draw off water by the pipe 180.
- 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 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.
- Check vales may also be provided at both the inlet and outlet which inhibit flow in both directions while closed and act to minimise heat transfer between water on either side of the inlet or outlet, to inhibit heat loss form the reservoir via the inlet and outlet.
- Pipes 140 used to deliver water from a hot water system storage tank 120 to water outlet fixtures such as taps and faucets are typically not insulated to minimize cost.
- the pipe 140 may hold a significant quantity of water which will cool while 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 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 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 meters of pipe to be between a hot water system and shower in an average home, this represents around 3-7 litres of water depending on the size of the pipe 140. This water will typically be wasted at least once every day representing a waste of around 1100 to 2555 litres per year.
- 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 piping material.
- the amount of waste water for a household can be significantly reduced.
- 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 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 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 50°C in new buildings.
- 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 50°C as the water is supplied to the bathroom hot water supply pipe 140.
- the mix down mechanism is not shown in the simple block diagram of Figure 1).
- the water supplied to the pipe 140 may be hotter as no mix down is required.
- we will consider the heated water 150 is supplied to pipe 140 at a temperature of 50°C.
- 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.
- the water entering the reservoir 1 10 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.
- 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 instantaneously.
- the water from the pipe 140 being mixed with the water in the reservoir 1 10 is cooled from sitting in the pipe so the temperature of the water in the reservoir will drop as a result of this mixing.
- the pipe 140 is flushed of cooled water by freshly heated water 150 the temperature of the water being mixed in the reservoir 1 10 will increase. This decrease and increase in water temperature will be gradual by virtue of the mixing and 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.
- 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 hot water system the amount of cold water entering the reservoir will vary.
- T min The minimum water temperature due to mixing of water from the pipe 140 with water stored in the reservoir 1 10 can be estimated using equation 1 below
- V P is the volume of water in the pipe
- Tpmin is the temperature the water in the pipe has cooled
- V R is the volume of water in the reservoir
- T Rmin is the temperature the volume of water in the reservoir has cooled to
- the reservoir has a capacity of around 10 litres and cools to around 45°C after 24 hours.
- the minimum temperature of water supplied from the reservoir T min is around 30°C. It should be appreciated that the minimum temperature calculation can only be an approximation as this calculation assumes that the entire volume of cooled water replaces water from the reservoir.
- water being 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 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 water in the reservoir at a temperature of 45°C.
- 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 140 and fresh hot water, at a temperature of 50°C, arrives at the reservoir 1 10.
- 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 with fresh hot water and the temperature of the reservoir reaches the maximum of 50°C.
- the minimum temperature in this example represents a worst case scenario and in practice the temperature may not drop to this minimum.
- water from the pipe 140 may be drawn off upstream of the reservoir 1 10 at other outlets (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 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 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 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 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 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 1 10 it will slowly cool and the rate at which the stored water will cool will vary depending on insulation, size and shape of the reservoir vessel.
- the reservoir size may be selected based on cooling over a 72 hour period to allow for cooling over a long weekend absence. If the reservoir is allowed to cool over a 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 mixes with cooled water in the reservoir to raise the temperature to a comfortable temperature for showering (between 36°C and 40°C) before all water in the reservoir is replaced.
- 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 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.
- the reservoir 110 is relatively squat and the inlet 160 and outlet 170 are both located in a lower portion of the 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.
- the inlet 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 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.
- the inlet and outlet are both located in an upper portion of the 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 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 in the reservoir as water is drawn off.
- 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.
- the same 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.
- 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.
- mixing of water is again aided by the flow of water through the reservoir and convection.
- cold water entering the top of the reservoir 1 10 via the inlet 160 will be caused by convection to move down through the reservoir to mix with the warmer water before exiting through the outlet 170.
- 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 lower portion of the reservoir.
- 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 reservoir equalises as water flows through the reservoir due to the combined effects of currents in the flowing water,
- baffles may be provided within the reservoir 1 10 to aid mixing of water within the reservoir 110 the baffles are designed to 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.
- Figures 5 to 7. Figure 5 shows an example of a reservoir 110 having four internal horizontal baffles to aid mixing of water stored 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.
- 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 in the reservoir 1 10 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 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.
- the inlet and outlet may be 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.
- Figure 6b shows an embodiment where both the inlet and outlet are located in the top of the reservoir. Pressurisation of the hot water system enables water to be drawn off the outlet as water flows into the reservoir in this example.
- baffles 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 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 shape of perforations.
- inlet and outlet position and baffle configuration Any arrangement of inlet and outlet position and baffle configuration is envisaged within the scope of the present 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.
- 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.
- a lattice 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.
- baffles for aiding mixing of 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.
- a fluid distributor is disposed within the reservoir attached to the inlet so that the inflowing water is dispersed into the reservoir via the fluid distributor rather than directly from the inlet.
- the fluid distributor can be configured to improve mixing of the fluid within the reservoir.
- the fluid distributor can be configured to distribute the inflowing water throughout the reservoir from multiple outlets form the fluid distributor, rather than from a single outlet. This will diffuse the incoming water throughout the reservoir to aid mixing.
- the fluid distributor may also be configured to enable some heat exchange between the stored water and inflowing water before the inflowing water mixes with the water held in the reservoir.
- the use of a fluid distributor reduces the likelihood of cooled water entering from the inlet and flowing directly to, then out of the outlet still cold without significantly mixing with the stored water.
- the fluid distributor can help to even out the temperature changes experienced during the initial stages of water flow before the water in the reservoir reaches the hot water service delivery temperature.
- FIG. 9 An example of a first embodiment of a fluid distributor is shown in Figure 9, where attached to the inlet 160 internal to the reservoir 1 10 is a helical coil tube 910 through which water flows before being release into the reservoir 1 10 to mix with the stored water.
- the helical coil can cause the water to swirl around the reservoir to improve mixing.
- the coil tube 910 can be made from a material, such as copper or aluminium, which enables heat exchange between the fluid in the coil tube and the reservoir before the fluid is released in to the reservoir.
- the coil tube 910 extends about half way into the reservoir, but this may vary between embodiments.
- the inlet and outlet may both be located next to each other in the base of the reservoir 1 10 with a coil tube fluid distributor attached to the inlet and extending to the top of the reservoir.
- a coil tube fluid distributor attached to the inlet and extending to the top of the reservoir.
- the helical coil tube is one example of a fluid distributor
- other forms of fluid distributor include but are not limited to pipes or sets of pipes, shell or plate shaped structures, configured to allow fluid to flow in from the inlet and out from one or more apertures in the structure. The number and location of apertures can vary between embodiments. Examples of different fluid distributor examples are shown in Figures 9 to 12 however, many alternative structures may be used.
- Figure 10 shows a sparge pipe type fluid distributor, having a pipe 1010 with a plurality of holes 1020 distributed along the length of the pipe 1010 to release fluid from the pipe 1010 throughout the reservoir. This arrangement ensures that there is some mixing of the cooled and stored water before release through the outlet.
- the number, size and arrangement of holes 1020 along the pipe 1010 can vary between
- Figure 11 shows an alternative fluid distributor having a wide flat hollow plate shaped structure 1110 with a plurality of holes 1120 in the surface.
- the fluid distributor is attached to the inlet 160 so fluid flows into the structure 1110 and out through the holes to mix with water in the reservoir.
- the plate shapes structure may comprise a series of interconnected pipes or internal channels to control fluid flow within the fluid distributor.
- the fluid dispenser may be a plurality of pipes interconnected in a mesh type structure.
- Figure 12 shows yet another fluid distributor embodiment comprising a tube 1210 and diffuser 1220 to release the inflowing water remote from the inlet 160 in an arraignment that enables the inlet and outlet to be placed proximate each other. This arrangement may have advantages for installation of the device because the inlet and outlet are located side by side.
- FIG. 13 An example of an embodiment is shown in Figure 13, in this embodiment the reservoir 110 is cylindrical having a volume of approximately 10 litres with an inlet (not shown) and outlet 170 at either end.
- Figures 14a and 14b show an example of modelled fluid flow in the reservoir 110 for a sparge pipe 1410 having a plurality of holes 1430 along its length.
- the sparge pipe 1410 is directly connected to the inlet 160 whereby fluid enters the pipe 1410. Fluid flows out of the sparge pipe from the holes 1430 to mix with the fluid in the reservoir 1450 and the mixed fluid flows form the reservoir 110 via the outlet 170.
- the modelled fluid flow for the fluid entering the reservoir is shown 1450 in Figure 14a.
- Figure 14b shows the holes 1430 in this embodiment are evenly spaced along the length of the sparge pipe 1410.
- Figure 14a there is more mixing near the outlet 170 end of the reservoir and relatively little mixing in the area 1420 near the inlet 160.
- Figures 15a and 15b show an alternative embodiment of a sparge pipe 1510 having a larger number of holes 1530 clustered near the inlet 160 end and holes spaced further apart 1540 near the outlet 170 end, and the resulting fluid flow model 1550.
- Figures 16a and 16b show a further alternative embodiment of a sparge pipe 1610 having fewer holes overall with a few holes 1630 near the inlet 160 and remaining 1640 holes widely spaced towards the outlet 170 and the resulting modelled fluid mixing pattern 1650.
- Figures 14a&b to 16a&b illustrate how different mixing results may be obtained from different configurations of the fluid distributor. It should be appreciated that the mixing results achieved can also vary based on fluid flow rate and vessel shape. Further the desired fluid flow patterns may also vary depending on relative location of the inlet and outlet.
- Embodiments having more than one outlet are also envisaged.
- an embodiment for installation in a bathroom may have one outlet to a shower fixture and one outlet to a faucet over a sink or bath.
- This embodiment may be desirable if there is insufficient space to install a unit for each of the sink and shower.
- the heated water in the reservoir may be refreshed more regularly that if used for the shower alone and hence have a higher starting temperature for the next shower.
- Such an embodiment may use a long narrow cylindrical reservoir body with the outlets located at either end or along the body.
- a suitably configured fluid distributor may be connected to the inlet to enabling mixing for either outlet. It should be appreciated that in such an
- output water pressure may be affected if both the sink and shower are used at the one time if the inflow from the inlet is less that the outflow demand when both outlets are open.
- Embodiments of the invention may be used with additional fittings to improve temperature control and convenience for the user.
- the outlet may be connected to a thermostatic mixing valve which includes a water temperature sensor and control mechanism to ensure that water is released at no hotter than a pre-set temperature (for example 40 degrees).
- the thermostatic mixing valve is connected to a cold water supply and hot water supply from the outlet. When the tap is turned on the thermostatic mixing valve senses the water temperature of the hot water and if this is less than the present limit, flow of water from the cold water supply is inhibited, once the temperature from the outlet reaches the pre-set temperature cold water is allowed to flow at a rate which maintains the output water temperature at the tap at the pre-set temperature.
- the inlet and outlet of the reservoir can be configured to minimise heat loss. In some embodiments this comprises insulating the inlet and outlet fittings. Valve configurations, such as double walled valves, check valves having an air evacuated centre, and dual direction check valves can also be used which reduce heat loss from the reservoir even if the valves are not required for water flow control.
- low thermal transfer materials may be used for connection of a fluid distributor to the reservoir inlet to reduce heat loss via the inlet. In such embodiments a low thermal conductivity material provides a buffer to reduce heat transfer between more highly thermally conductive internal and external components.
- a high thermal conductivity copper sparge pipe may be connected to the inlet via a section of low thermal conductivity material, such as PVC pipe to reduce heat transfer from water within the reservoir to the inlet, fittings and hot water pipe connected thereto to reduce overall heat loss.
- the fluid distributor may be formed of low thermal conductivity material to reduce heat loss via conductivity to external fittings.
- thermal conductivity of the fluid distributor is not necessary.
- each of the inlet and outlet may use dual fittings and insulation around the reservoir inlet and outlet to reduce heat loss.
- each of the inlet and outlet has an internal and external fitting which include check valves to inhibit flow of water unless the tap/shower is operated.
- An insulated cavity is provided in the reservoir casing proximate the inlet and outlet, the internal inlet and outlet fittings are connected to the external inlet and outlet fittings via respective lengths of low heat transfer pipe coiled within the insulated cavity.
- the external fixtures can also include check valves to minimise heat transfer.
- This configuration provides a buffer zone between the reservoir and the external water pipes to reduce heat loss from the reservoir via the inlet and outlet fittings. Having such a buffer reduces the rate at which heat may be lost from the water stored in the reservoir. Reduction of heat loss may also be achieved by improved insulation of the inlet an outlet fittings and using low heat transfer materials for construction of the fittings.
- FIG. 17 A comparative example of hot water temperatures using an embodiment of the present invention and without is show in in Figure 17.
- line 1710 shows the expected temperature for a normal shower where no device in accordance with embodiments of the invention is installed.
- Line 1720 shows the expected temperature change over time for water pipes and a device of the present invention given the hot water service initial temperature is 65°C, pipe length is 10 metres, and reservoir capacity of 10 litres and the initial cooling period is 24 hours.
- Line 1730 shows the temperature profile for the reservoir alone. The initial part of the graph represents heat loss over a 24 hour period and it should be appreciated that in this graph the time axes is not to scale. At a time (2) when a person turns on the shower the water in the pipes has cooled to around 15°C.
- the water at the shower stays at this temperature until all the cooled water is purged from the water pipes.
- the device installed as represented by lines 1720 and 1730 at the time when the shower is turned on the temperature is around 40°C and this temperature drops slightly until the time (3) as the cooled water is purged from the water pipes, but only to a temperature of around 36°.
- the water temperature then rises until the water in the reservoir reaches the temperature of the hot water from the hot water service.
- the shower temperature can be significantly improved using the device of embodiment sof the present invention.
- Figure 18 shows comparative examples of temperature changes for different configurations and cooling times.
- the hot water service temperature in these examples is 65°C.
- the temperature profile represented by line 1810 is for an embodiment where the cooling time is 24 hours and the pipe length is 10 metres
- line 1820 represents an embodiment where the cooling time is 24 hours and the pipe length is 20 meters
- line 1830 represents an embodiment where the cooling time is 48 hours and the pipe length is 10 meters
- line 1840 represents an embodiment where the cooling time is 48 hours and the pipe length is 20 meters.
- Embodiments of the present invention may be installed with 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 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.
- Additional features of the reservoir may include pressure release valves, draining/spill pans and additional outlets for draining. Inclusion of such additional features may 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.
- 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 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 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.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Thermal Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
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- Water Supply & Treatment (AREA)
- Heat-Pump Type And Storage Water Heaters (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/782,279 US9890960B2 (en) | 2013-04-04 | 2014-02-07 | Water saving apparatus |
AU2014214540A AU2014214540A1 (en) | 2013-04-04 | 2014-02-07 | Water saving apparatus |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2013900385 | 2013-02-07 | ||
AU2013900385A AU2013900385A0 (en) | 2013-02-07 | Water saving apparatus | |
AU2013202532A AU2013202532B2 (en) | 2013-02-07 | 2013-04-04 | Water saving apparatus |
AU2013202532 | 2013-04-04 |
Publications (1)
Publication Number | Publication Date |
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WO2014121335A1 true WO2014121335A1 (en) | 2014-08-14 |
Family
ID=51299083
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/AU2014/000093 WO2014121335A1 (en) | 2013-02-07 | 2014-02-07 | Water saving apparatus |
Country Status (2)
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AU (1) | AU2013202532B2 (en) |
WO (1) | WO2014121335A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6431581B1 (en) * | 2017-08-03 | 2018-11-28 | 株式会社Mirai−bs | Water pipe cleaning method |
FR3072765A1 (en) * | 2017-10-24 | 2019-04-26 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | DEVICE FOR HEATING A CIRCULATING FLUID IN A PIPING AND THERMAL INSTALLATION COMPRISING SUCH A DEVICE |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB588729A (en) * | 1944-11-29 | 1947-06-02 | Sulzer Bros London Ltd | Improvements in or relating to hot water storage systems and indicators therefor |
US20050166313A1 (en) * | 2004-02-02 | 2005-08-04 | Permenter John B. | Insulated hot water storage tank for sink |
-
2013
- 2013-04-04 AU AU2013202532A patent/AU2013202532B2/en not_active Ceased
-
2014
- 2014-02-07 WO PCT/AU2014/000093 patent/WO2014121335A1/en active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB588729A (en) * | 1944-11-29 | 1947-06-02 | Sulzer Bros London Ltd | Improvements in or relating to hot water storage systems and indicators therefor |
US20050166313A1 (en) * | 2004-02-02 | 2005-08-04 | Permenter John B. | Insulated hot water storage tank for sink |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6431581B1 (en) * | 2017-08-03 | 2018-11-28 | 株式会社Mirai−bs | Water pipe cleaning method |
FR3072765A1 (en) * | 2017-10-24 | 2019-04-26 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | DEVICE FOR HEATING A CIRCULATING FLUID IN A PIPING AND THERMAL INSTALLATION COMPRISING SUCH A DEVICE |
EP3477211A1 (en) * | 2017-10-24 | 2019-05-01 | Commissariat à l'Energie Atomique et aux Energies Alternatives | Device for heating a fluid flowing in a pipe and thermal installation comprising such a device |
Also Published As
Publication number | Publication date |
---|---|
AU2013202532B2 (en) | 2015-02-19 |
AU2013202532A1 (en) | 2014-08-21 |
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