AU2020257065A1

AU2020257065A1 - Hot Water System

Info

Publication number: AU2020257065A1
Application number: AU2020257065A
Authority: AU
Inventors: Edward CUMMINS
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-21
Filing date: 2020-10-20
Publication date: 2021-05-06

Abstract

HOT WATER SYSTEM ABSTRACT There is disclosed a hot water system (10) including a water heater (12) operatively adapted to store and heat an amount of water. The water heater (12) includes a water heater inlet (14) through which water is introduced into the water heater (12) and a water heater outlet (16) through which heated water is discharged from the water heater (12). The water heater outlet (16) is located at a position above the water heater inlet (14). The hot water system (10) further includes a water supply assembly (22) in fluid communication with the water heater inlet (14) and a water discharge assembly (26) in fluid communication with the water heater outlet. The water supply assembly (22) includes an expansion tank (30) to accommodate an increase in water volume resulting from water being heated by the water heater (12).

Description

HOT WATER SYSTEM FIELD

[0001] The invention concerns a hot water system, particularly but not exclusively, a hot water system for use in heating potable water. The invention extends to a storage unit for a hot water system.

BACKGROUND

[0002] Heated water is required for various applications in both domestic and industrial settings. For domestic use, potable water is often heated inside tank-type water heaters. One example tank type water heater includes a storage tank having heating elements to heat water inside the tank. Other tank-type water heaters include alternative heat sources for heating. Such alternative heat sources could be internal or external of the storage tank and include for example gas, solar, electric, heat pump and heating boilers. The water heater not only serves to heat water, but also stores heated water until required for use. The water heater is accordingly fitted with insulation to keep heated water warm between heating cycles.

[0003] In Australia the storage tank of a water heater has a hot water delivery arrangement at its top and a supply arrangement at its bottom. In use the supply arrangement delivers cold water from a water mains supply to the water heater. As heated water has a density which is lower than that of cold water, heated water will rise to the top of a water heater. The hot water delivery arrangement is adapted to take hot water from the top of the water heater and deliver it to, for example, an open hot water tap.

[0004] A water heater has the potential to explode should temperature and pressure levels exceed the mechanical strength of its storage tank. An exploding water heater can cause significant damage to a building and possibly cause the injury or even death of persons in the vicinity of the explosion. For this reason, plumbing codes around the world require that water heaters be fitted with safety devices. One such safety device is a temperature / pressure-relief valve, commonly referred to as a TPR valve. The TPR valve is fitted at the top of the water heater and serves to discharge heated water from the water heater should temperature or pressure levels exceed a predetermined value. Most plumbing codes require that a discharge pipe be connected to the TPR valve for directing discharged hot water to a drain.

[0005] In a typical domestic setting TPR valves will discharge small amounts of heated water throughout the course of a day. Over an extended period the accumulated volume of water so discharged can be significant. Multiplying the volume of water discharged by an average household with the number of households employing a water heater which discharges heated water through a TPR valve amounts to a significant waste of water. It goes without saying that water is a valuable and scarce resource and that it would be beneficial if the amount of water lost through a TPR valve could be reduced.

OBJECT

[0006] It is an object of the present invention to provide a hot water system which addresses the waste of water through a temperature / pressure-relief (TPR) valve, or at least to provide an alternative hot water system.

SUMMARY

[0007] According to a first aspect of the present invention there is disclosed herein a hot water system including:

a water heater operatively adapted to store and heat an amount of water, the water heater including a water heater inlet through which water is introduced into the water heater and a water heater outlet through which heated water is discharged from the water heater, the water heater outlet being located at a position above the water heater inlet;

a water supply assembly in fluid communication with the water heater inlet; and

a water discharge assembly in fluid communication with the water heater outlet,

wherein the water supply assembly includes an expansion tank to accommodate an increase in water volume resulting from water being heated by the water heater.

[0008] Preferably the expansion tank defines an inner volume.

[0009] Preferably the expansion tank includes a diaphragm located inside the inner volume.

[0010] Preferably the diaphragm divides the inner volume into an air chamber and a water chamber.

[0011] Preferably the expansion tank includes a valve operatively adapted to permit air to flow into and out from the air chamber of the inner volume.

[0012] Preferably the valve is a Schrader valve.

[0013] Preferably the expansion tank includes an expansion tank inlet operatively adapted to permit the flow of water into and out from the expansion tank.

[0014] Preferably the diaphragm is moveable between (i) a rest condition in which the diaphragm closes off the expansion tank inlet to deter the flow of water into the water chamber, and (ii) an operative condition in which the diaphragm is displaced from the expansion tank inlet to permit water to enter and fill the water chamber of the expansion tank.

[0015] Preferably the expansion tank inlet of the expansion tank is adapted to be connected to a T-shaped connector.

[0016] Preferably the expansion tank inlet of the expansion tank is adapted to be coupled to a tank coupling provided by the vertical leg of the T-shaped connector.

[0017] Preferably a horizontal leg of the T-shaped connector defines a mains side mouth and a water heater-side mouth.

[0018] Preferably the water supply assembly includes a pressure limiting valve (PLV).

[0019] Preferably the pressure limiting valve is located between a mains water supply and the mains side mouth of the T-shaped connector.

[0020] Preferably the water supply assembly includes a non-return valve.

[0021] Preferably the non-return valve is located between the mains water supply and the pressure limiting valve.

[0022] Preferably the water supply assembly includes a stop valve.

[0023] Preferably the stop valve is located between the mains water supply and the non-return valve.

[0024] Preferably the water discharge assembly includes a hot water tempering valve.

[0025] Preferably the hot water tempering valve is in fluid communication with the water heater outlet via an outlet conduit.

[0026] Preferably the water heater-side mouth of the T-shaped connector is in fluid communication with the water heater inlet via an inlet conduit.

[0027] Preferably the inlet conduit is in fluid communication with the hot water tempering valve of the water discharge assembly.

[0028] Preferably the water heater includes a temperature/pressure-relief valve (TPR).

[0029] According to a second aspect there is disclosed herein a water storage unit having a housing for operative installation within a water supply assembly in fluid communication with a water heater inlet of a water heater, the housing holding (i) an expansion tank operatively adapted to accommodate an increase in water volume resulting from water being heated by the water heater, and (ii) a pressure limiting valve (PLV) operatively associated with the expansion tank.

[0030] Preferably the water storage unit includes a unit inlet and a unit outlet adapted respectively to couple with the water supply assembly so that water from the water supply assembly will enter the water storage unit via the unit inlet, pass through the pressure limiting valve and the expansion tank and re-enter the water supply assembly through the unit outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Preferred embodiments of the invention will be described hereinafter, by way of examples only, with reference to the accompany drawings, wherein:

[0032] Figure 1 is a diagrammatic representation of an embodiment hot water system;

[0033] Figure 2 is a diagrammatic representation of an expansion tank for use in the embodiment hot water system wherein a diaphragm of the expansion tank is in a rest condition;

[0034] Figure 3 is a diagrammatic representation of the expansion tank of Figure 2 wherein the diaphragm is in an operative condition;

[0035] Figure 4 is a diagrammatic representation of a second embodiment hot water system; and

[0036] Figure 5 is an embodiment water storage unit for a hot water system.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0037] Figure 1 shows a first embodiment hot water system, generally indicated with the reference numeral 10. The hot water system 10 includes a cylindrical tank-type water heater 12 operatively adapted to store and heat an amount of water. In this embodiment the water heater 12 has a capacity of 3151 and includes non-illustrated electrical heating elements for heating water stored within the water heater 12. It will be appreciated that the water heater 12 need not employ an electric element and that other heating systems, for example gas burners, may be employed to heat the stored water.

[0038] The water heater 12 includes a water heater inlet 14, through which water is introduced into the water heater 12 in order to fill it, and a water heater outlet 16 through which heated water is discharged. The water heater outlet 16 is located at a position above the water heater inlet 14. In this embodiment the cylindrical water heater 12 is orientated with its longitudinal axis in an upright position. The water heater 12 has a domed top end 18 and an opposing bottom end 20. As shown the water heater outlet 16 is located towards the top end 18 of the water heater 12 while the water heater inlet 14 is located towards the bottom end 20.

[0039] The water heater 12 includes a temperature/pressure-relief (TPR) valve 21 located towards the top end 18. The TPR valve serves to discharge heated water from the water heater 12 if the temperature or pressure within the water heater 12 exceeds a predetermined value. The TPR valve 21 is coupled to a discharge conduit 23 to feed discharged hot water to a drain 25.

[0040] The water heater inlet 14 is placed in fluid communication with a water supply assembly 22 via an inlet union 24. The water heater outlet 16, in turn, is placed in fluid communication with a water discharge assembly 26 via an outlet union 28.

[0041] The water supply assembly 22 includes an expansion tank 30 operatively adapted to accommodate an increase in water volume resulting from water being heated in the water heater 12. The embodiment expansion tank 30 is produced from a material suitable for storing potable water, for example stainless steel. The embodiment expansion tank 30 defines an inner volume 32. A non-toxic diaphragm 34 is located within the inner volume 32 and divides the inner volume 32 into an air chamber 33 and a water chamber 35, illustrated in Figure 3. The expansion tank 30 includes a valve 40, here in the form of a Schrader valve, which is operatively adapted to permit air to flow into the air chamber 33 of the inner volume 32.

[0042] Referring also to Figures 2 and 3, the expansion tank 30 includes an expansion tank inlet 42 operatively adapted to be coupled to a tank coupling 43 provided by the vertical leg 45 of a T shaped connector 48. In this embodiment the expansion tank inlet 42 has an outer thread 44 which is operatively adapted to engage a complementally threaded recess 46 providing the tank coupling 43. A horizontal leg 50 of the T-shaped connector 48 defines a mains side mouth 52 and a water heater-side mouth 54. In use water from a water mains supply will enter the T-shaped connector

48 via the mains side mouth 52 and flow in the direction of arrows 56 to exit at the water heater side mouth 54 to flow to the water heater 12.

[0043] The diaphragm 34 is moveable between (i) a rest condition (shown in Figure 2) in which the diaphragm 34 closes off the expansion tank inlet 42 to deter the flow of water into the water chamber 35 of the inner chamber 32, and (ii) an operative condition (shown in Figure 3) in which the diaphragm 34 is displaced from the expansion tank inlet 42 to permit water to enter the expansion tank 30 and into the water chamber 35 so as to push the diaphragm 34 into an expanded condition upwards into the inner volume 32 and to reduce the volume of the air chamber 33. Operation of the expansion tank 30 is discussed in detail below.

[0044] The water supply assembly 22 includes a pressure limiting valve (PLV) 58 located between a mains water supply 60 and the mains side mouth 52 of the T-shaped connector 48. In this embodiment the pressure limiting valve 58 is set to 500kPa in accordance with Australian Standard AS3500. The water supply assembly 22 further includes a non-return valve 62 located between the mains water supply 60 and the pressure limiting valve 58 to prevent water returning to the mains water supply 60. The water supply assembly 22 also includes a stop valve 64 located between the mains water supply 60 and the non-return valve 62 to control the flow of water from the mains water supply 60 into the hot water system 10.

[0045] It is pointed out that pressure of air in the air compartment 33 of the embodiment expansion tank 30 is set to a value of 72.5psi. That value corresponds to the 500kPa water pressure regulated by the pressure limiting valve 58. It is further pointed out that the air pressure in the air compartment 33 is set to 72.5psi before the hot water system 10 is filled with water to prevent a false air pressure reading. It will be appreciated that if the value of the pressure limiting valve 58 were to change, a corresponding change to the pressure of air inside the air compartment 33 would be required.

[0046] The water discharge assembly 26 includes a hot water tempering valve (TV) 66 which ensures that water is discharged from the hot water system at a maximum temperature of 50°C in accordance with Australian building regulations. The hot water tempering valve 66 is in fluid communication with the water heater outlet 16 via an outlet conduit 68, while the water heater side mouth 54 of the T-shaped connector 48 is in fluid communication with the water heater inlet 14 via an inlet conduit 70. The inlet conduit 70 further is in fluid communication with the hot water tempering valve 66 of the water discharge assembly 26 via a branch conduit 72. The branch conduit 72 couples with the hot water tempering valve 66 by way of a tempering valve union 74 which is also a non-return valve. As an alternative, hot water need not pass through the hot water tempering valve 66 and can be delivered directly to a tap via a conduit assembly 67.

[0047] Once the embodiment hot water system 10 has been installed and coupled to the mains water supply 60 it is filled with cold water by opening the inlet stop valve 64. During the filling process a non-illustrated hot water tap is opened to allow all air to be vented from the hot water system 10. The hot water tap is turned off when all air has been vented and water starts to flow through the tap. The hot water system 10 is now filled with cold water.

[0048] Pressure within the hot water system 10 will increase under the influence of the mains water supply pressure. The pressure in the hot water system 10 will stop increasing when the pressure of the hot water system 10 either equals (i) the mains water supply pressure, or (ii) the 500kPa pressure setting of the pressure limiting valve 58, whichever pressure of (i) or (ii) is lower. Energy is now applied to the water heater 12 to heat stored cold water. The heated water will begin to expand and increase in volume. The additional volume of water is unable to expand back into the mains water supply 60 due to the presence of the non-return valve 62. If no hot water taps or hot water connections are used during the heating cycle all expansion in water volume will occur inside the expansion tank 30 as discussed below.

[0049] Expanding water will push up into the expansion tank 30 via the T-shaped connector as this will provide the path of least resistance. Continued expansion of the water will push the diaphragm 34 against the pressure in the air chamber 33 away from the expansion tank inlet 42, shown in Figure 3, and start to fill the water chamber 35 of the expansion tank 30. As the expansion tank 30 is filled with water the diaphragm 34 will expand upwards into the inner volume 32 to compress the air in the air chamber 33. Once the water reaches a temperature of 70°C a non-illustrated thermostat of the water heater 12 will cause the water heater 12 to stop heating. Expanded water will remain within the expansion tank 30 and not leak out via the TPR valve.

[0050] When a hot water tap or hot water outlet is opened hot water will start to flow. The water pressure in the hot water system 10 will now be lower than the air pressure inside air chamber 33 of the inner volume 32 of the expansion tank 30. The pressure exerted by air inside the air chamber 33 will push all the extra water volume inside the water chamber 35 of the expansion tank 30 back towards the water heater 12.

[0051] When the open hot water tap is turned off water will no longer flow. As a result, the pressure in the hot water system 10 again increases to the mains water supply pressure or to the

500kPA pressure setting of the pressure limiting valve (PLV) 58, whichever is less. Thehotwater system pressure and the air pressure of air in the air chamber 33 of the expansion tank 30 are again of equal magnitude. The heating cycle restarts and expanded water is again stored in the expansion tank 30 as discussed above.

[0052] By way of example, water heated from 20°C to 80°C will expand at a rate of 0.027L for every 1 litre heated (Ref: Rheem Hot Water Manual, Chapter 17). An electric water heater with a 250L capacity will expand 6.75L when water is heated from 20°C to 80°C. It is believed that it may be possible to save at large percentage of the 6.75L of expanded water as opposed to it being discharged through the TPR valve.

[0053] The energy required to heat water can be calculated with the following formula:

Heat Energy (MJ) = Mass (kg) x specific heat capacity of water x temperature rise

(Ref: Rheem Hot Water Manual, Chapter 16)

[0054] Using the above example to calculate the energy required to raise 6.75L from 20°C to °C is as follows:

Heat energy (MJ)= 6.75L x 0.004186MJ/kg/C x 60°C

Heat energy (MJ)= 1.69533 (energy required)

[0055] Taking heater efficiency into consideration the actual energy required is calculated as heat energy +efficiency/ 100.

MJ= 1.69533 +89%/100

MJ= 1.69533 +0.89

MJ= 1.9048 or 0.529kW/h

[0056] A household using 250L per day potentially could save 6.75L water per day and 2463.75L per year as well as saving 0.529kW/h per day and 193.1kW/h per year. It would be appreciated that saving can be greater or less depending on individual household usage.

[0057] Figure 4 shows a second embodiment hot water system 100. The hot water system 100 is similar to the first embodiment hot water system 10 in that it includes a water supply assembly 22 water heater 12, an expansion tank 30, a T-shaped connector 48, a pressure limiting valve 58, a non-return valve 62 and a stop valve 64. The water supply assembly 22 supplies water from a mains water supply 60 to the water heater 12. In this embodiment an expansion control valve (ECV) 102 for feeding water to a drain 104. The ECV 102 is located between the expansion tank and the water inlet 14. The ECV will be employed in states, for example South Australia and Western Australia, where an ECV is required in terms of relevant building regulations.

[0058] The hot water system 100 includes a water discharge assembly 26 which provides a hot water return assembly 106 which returns water to the water supply assembly 22. The water discharge assembly 26 includes a plurality of conduits 108 to supply hot water to non-illustrated hot water taps. The hot water return assembly 106 mouths into the water supply 22 at a position between the ECV 102 and the heater inlet 14. The hot water return assembly 106 includes a circulating pump 110 located in position via unions 112. The hot water return assembly 106 further includes two stop valves 114 and a non-return valve 116.

[0059] Figure 5 shows an embodiment water storage unit 200 which is adapted to be fitted or retrofitted to a hot water system 202. The water storage unit 200 includes a housing 204 for operative installation within a water supply assembly 22 in fluid communication with a non illustrated water heater inlet of a water heater. The housing 204 holds an expansion tank 30 operatively adapted to accommodate an increase in water volume, as discussed above, resulting from water being heated by the water heater. The housing 204 also holds a pressure limiting valve (PLV) 58 operatively associated with the expansion tank 30. The pressure limiting valve 58 is in fluid connection with the expansion tank 30 via a conduit 206. The conduit 206 is coupled with a T-shaped connector 48 which, in turn, is coupled to the expansion tank 30.

[0060] The water storage unit 200 includes a unit inlet 208, here in the form of a conduit, which is coupled to the pressure limiting valve 58 at one end. At another end the unit inlet 208 includes a threaded connector 210 adapted to threadingly connect to a complemental threaded connector 212 of an inlet conduit 70.1. The inlet conduit 70.1 is in fluid communication with a non-return valve 62, a stop valve 64 and a main water supply 60 of a conventional hot water system 201.

[0061] The water storage unit 200 further includes unit outlet 214 having a threaded connector 216 adapted to threadingly connect to a complemental threaded connector 218 of an inlet conduit 70.2 of the water supply assembly 22. In effect water from the water supply assembly 22 will enter the water storage unit 200 via the unit inlet 208, pass through the pressure limiting valve 58 and the expansion tank 30 and then re-enter the water supply assembly 22 through the unit outlet 214. The operation of the expansion tank 30 and pressure limiting valve 58 of the water storage unit 200 is as described above with the difference that the water storage unit can be retrofitted with relative ease to an existing hot water system due to presence of the housing 204 and the threaded unit inlet 208 and unit outlet 214.

[0062] Although the invention has been described with reference to a specific example, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

KEY TO REFERENCE NUMERALS IN DRAWINGS

Hot water system 12 Water heater 14 Water heater inlet 16 Water heater outlet 18 Top end Bottom end 21 Temperature / pressure-relief valve (TRV) 22 Water supply assembly 24 Inlet union 26 Water discharge assembly 28 Outlet union Expansion tank 32 Inner volume 33 Air chamber 34 Bladder Water chamber Valve 42 Expansion tank inlet 43 Tank coupling 44 Outer thread - mouth Vertical leg 46 Threaded recess 48 T-shaped connector Horizontal leg 52 Mains side opening 54 Water heater side mouth 56 Arrow / direction

58 Pressure limiting valve (PLV) Mains water supply 62 Non-return valve 64 Stop valve 66 Hot water tempering valve 67 Conduit assembly 68 Outlet conduit Inlet conduit 70.1 Inlet conduit 72 Branch outlet 74 Tempering valve union 100 Second embodiment hot water system 102 Expansion control valve (ECV) 104 Drain 106 Hot water return assembly 108 Conduits 110 Circulating pump 112 Unions 114 Stop valves 116 Non-return valve 200 Water storage unit 201 Convention hot water system 202 Hot water system 204 Housing 206 Conduit 208 Unit inlet 210 Threaded connector 212 Threaded connector 214 Unit outlet 216 Threaded connector 218 Threaded connector

Claims

CLAIM

1. A hot water system including:

a water supply assembly in fluid communication with the water heater inlet; and

a water discharge assembly in fluid communication with the water heater outlet,

2. A hot water system according to claim 1, wherein the expansion tank defines an inner volume.

3. A hot water system according to claim 2, wherein the expansion tank includes a diaphragm located inside the inner volume.

4. A hot water system according to claim 3, wherein the diaphragm divides the inner volume into an air chamber and a water chamber.

5. A hot water system according to claim 4, wherein the expansion tank includes a valve operatively adapted to permit air to flow into and out from the air chamber of the inner volume.

6. A hot water system according to claim 5, wherein the valve is a Schrader valve.

7. A hot water system according to claim 5, wherein the expansion tank includes an expansion tank inlet operatively adapted to permit the flow of water into and out from the expansion tank.

8. A hot water system according to claim 7, wherein the diaphragm is moveable between (i) a rest condition in which the diaphragm closes off the expansion tank inlet to deter the flow of water into the water chamber, and (ii) an operative condition in which the diaphragm is displaced from the expansion tank inlet to permit water to enter and fill the water chamber of the expansion tank.

9. A hot water system according to claim 8, wherein the expansion tank inlet of the expansion tank is adapted to be connected to a T-shaped connector.

10. A hot water system according to claim 9, wherein the expansion tank inlet of the expansion tank is adapted to be coupled to a tank coupling provided by the vertical leg of the T shaped connector.

11. A hot water system according to claim 10, wherein a horizontal leg of the T-shaped connector defines a mains side mouth and a water heater-side mouth.

12. A hot water system according to claim 11, wherein the water supply assembly includes a pressure limiting valve (PLV).

13. A hot water system according to claim 12, wherein the pressure limiting valve is located between a mains water supply and the mains side mouth of the T-shaped connector.

14. A hot water system according to claim 13, wherein the water supply assembly includes a non-return valve.

15. A hot water system according to claim 14, wherein the non-return valve is located between the mains water supply and the pressure limiting valve.

16. A hot water system according to claim 15, wherein the water supply assembly includes a stop valve.

17. A hot water system according to claim 16, wherein the stop valve is located between the mains water supply and the non-return valve.

18. A hot water system according to claim 17, wherein the water discharge assembly includes a hot water tempering valve.

19. A hot water system according to claim 18, wherein the hot water tempering valve is in fluid communication with the water heater outlet via an outlet conduit.

20. A hot water system according to claim 19, wherein the water heater-side mouth of the T shaped connector is in fluid communication with the water heater inlet via an inlet conduit.

21. A hot water system according to claim 20, wherein the inlet conduit is in fluid communication with the hot water tempering valve of the water discharge assembly.

22. A hot water system according to claim 21, wherein the water heater includes a temperature/pressure-relief valve (TPR).

23. A water storage unit having a housing for operative installation within a water supply assembly in fluid communication with a water heater inlet of a water heater, the housing holding (i) an expansion tank operatively adapted to accommodate an increase in water volume resulting from water being heated by the water heater, and (ii) a pressure limiting valve (PLV) operatively associated with the expansion tank.

24. A water storage unit according to claim 23, wherein the water storage unit includes a unit inlet and a unit outlet adapted respectively to couple with the water supply assembly so that water from the water supply assembly will enter the water storage unit via the unit inlet, pass through the pressure limiting valve and the expansion tank and re-enter the water supply assembly through the unit outlet.

Edward Cummins Patent Attorneys for the Applicant Meyer West IP