Technical Field

[0001] The present invention relates to a heating system, e.g. a water heating system. Further, the present invention relates to a method of heating and dispensing water. The present invention may relate to a water heating system suitable for providing heated water for an activity of short duration. The present invention may relate to a water heating system having a small storage volume.

Background

[0002] Water heaters are commonly used for supplying hot water for a variety of uses, e.g. drinking, bathing. Water heaters may be a storage heater or an instant heater, i.e. a tankless heater. As the temperature of water supply in most places are below average body temperature, a person taking a bath may find the supplied water to be cold and uncomfortable. In countries with cold climate, it may be more unbearable to take a bath without heated water.

[0003] Water heaters used to heat the water supply require relatively high-power consumption. For example, a typical storage heater may require 1.5 kW and has a capacity of about 20L- 400L and a typical instant heater may require 3kW-4kW power consumption. Furthermore, for activities, e.g. bathing, that require a prolong period of heated water supply, the power consumption increases with the duration of the activity. For example, for a storage heater having a power consumption of 1.5kW, the time required to heat up the water in a storage tank of 35L is about 28 minutes and the power consumption is about 0.7kW. For an instant heater having a power consumption of 3kW, an activity of 8 mins, e.g. bathing, consumes about 0.4kW of power. In areas where power supply is inconsistent or insufficient, it is not possible for such water heaters to be used. In areas where cost of electricity is relatively high, it may be expensive to use water heaters.

[0004] Further, the heating rate of the storage heater is slow. For long-period activities, e.g. bathing, the stored hot water may run out before the activity ends and the use would have to wait for a while before the water in the storage heater is heated sufficiently again. If there are many users who need to bath, they would have to wait for the water in the storage heater to be heated before they can take their bath if the hot water runs out.

[0005] More importantly, it is beneficial to reduce the power consumption of water heater to save energy and its associated costs.

Summary

[0006] According to various embodiments, a water heating system is provided. Water heating system includes a storage heater having a first outlet, the storage heater adapted to heat a water volume therein and dispense the water volume as a first water flow via the first outlet, an instant heater having a second outlet, the instant heater adapted to instantly heat and dispense a second water flow via the second outlet, and a dispensing outlet adapted to connect to and in fluid communication with the first outlet and the second outlet, such that the dispensing outlet is adapted to receive and dispense the first water flow or the second water flow or a mixture of the first water flow and the second water flow.

[0007] According to various embodiments, the storage heater may be configured to be turned off to cease the heating of the water volume when the instant water is turned on to commence the heating of the second water flow.

[0008] According to various embodiments, the water heating system may further include a mixer before the dispensing outlet, such that the mixer may be adapted to mix the first water flow and the second water flow.

[0009] According to various embodiments, the mixer may be configured to mix the first water flow and the second water flow in a ratio from 1:0 to 1:700.

[0010] According to various embodiments, the mixer may be configured to mix the first water flow and the second water flow in a ratio from 1:0 to 1:8.

[0011] According to various embodiments, the water volume may be stored and heated in a storage heater adapted to dispense the first water flow. [0012] According to various embodiments, the storage heater may have a capacity of 0.5 to 500 litres.

[0013] According to various embodiments, the storage heater may have a capacity of 5 litres or less.

[0014] According to various embodiments, the storage heater may have a power input in the range of O.lkW to 20 kW.

[0015] According to various embodiments, the storage heater may have a power input in the range of 0.2kW to 3.5kW.

[0016] According to various embodiments, the storage heater may have a power input in the range of 0.2kW to 1.5kW.

[0017] According to various embodiments, the instant heater may have a power input in the range of O.lkW to 20kW.

[0018] According to various embodiments, the instant heater may have a power input in the range of 0.2kW to 3.5kW.

[0019] According to various embodiments, the instant heater may have a power input in the range of 0.2 kW to 1.5kW.

[0020] According to various embodiments, a method of heating and dispensing water may be presented. Method of heating and dispensing includes heating a water volume and dispensing the water volume as a first water flow, heating a second water flow instantly and dispensing the second water flow, and receiving and dispensing the first water flow or the second water flow or a mixture of the first water flow and the second water flow. [0021] According to various embodiments, the heating of the water volume may be ceased when the heating of the second water flow commences.

[0022] According to various embodiments, the method may further include mixing the first water flow and the second water flow before dispensing the mixture of the first water flow and the second water flow.

[0023] According to various embodiments, the first water flow and the second water flow may be mixed in a ratio from 1:0 to 1:700.

[0024] According to various embodiments, the first water flow and the second water flow may be mixed in a ratio from 1:0 to 1:8.

[0025] According to various embodiments, the storage heater may have a capacity of 0.5 to 20 litres.

[0026] According to various embodiments, the storage heater may have a capacity of 5 litres or less.

[0027] According to various embodiments, the storage heater may have a power input in the range of O.lkW to 20 kW.

[0028] According to various embodiments, the storage heater may have a power input in the range of 0.2kW to 1.5kW.

[0029] According to various embodiments, the storage heater may have a power input in the range of 0.2kW to 3.5kW.

[0030] According to various embodiments, the second water flow may be heated by an instant heater adapted to dispense the second water flow. [0031] According to various embodiments, the instant heater may have a power input in the range of 0.1 kW to 20kW.

[0032] According to various embodiments, the instant heater may have a power input in the range of 0.2kW to 3.5kW.

[0033] According to various embodiments, the instant heater may have a power input in the range of 0.2kW to 1.5kW.

Brief Description of Drawings

[0034] Fig. 1 shows an exemplary embodiment of a water heating system.

[0035] Fig. 2 shows a method of heating and dispensing water based on the water heating system of Fig. 1.

[0036] Fig. 3 shows an exemplary embodiment of the water heating system.

Detailed Description

[0037] Fig. 1 shows an exemplary embodiment of a water heating system 100. Water heating system 100 includes a storage heater 110 having a first outlet 112. Storage heater 110 is adapted to heat a water volume therein and dispense the water volume as a first water flow via the first outlet 112. Water heating system 100 has an instant heater 120 having a second outlet 122. Instant heater 120 is adapted to instantly heat and dispense a second water flow via the second outlet 122. Water heating system 100 has a dispensing outlet 132 adapted to connect to and in water communication with the first outlet 112 and the second outlet 122, such that the dispensing outlet 132 is adapted to receive and dispense the first water flow or the second water flow or a mixture of the first water flow and the second water flow. As shown in Fig. 1, the storage heater 110 may have a first inlet 114 for receiving a first water supply into the storage heater 110. Instant heater 120 may have a second inlet 124 for receiving a second water supply into the instant heater 120. A main inlet (not shown in Fig. 1) may be connected to and in fluid communication with the first inlet 114 and the second inlet 124. Main inlet may be connected to a water supply (not shown in Fig. 1) to supply water to the first inlet 114 and the second inlet 124.

[0038] When the water heating system 100 in turned on, the storage heater 110 may be activated or turned on to heat up the water volume therein. When the water volume is heated up to a pre-determined temperature, e.g. in the range of 30-100°C, the water heating system 100 is ready to be used for dispensing heated water. When the water is released from the water heating system 100 via the dispensing outlet 132, e.g. by turning on a valve attached to the dispensing outlet 132, the first water flow and the second water flow may be dispensed from the storage heater 110 and the instant heater 120 simultaneously. When the second water flow is being dispensed, the instant heater 120 may be activated to heat the second water flow therethrough to commence heating the second water flow. Concurrently, the storage heater 110 may be turned off to cease the heating of the water volume when the instant heater 120 is turned on to commence the heating of the second water flow. In this way, while the power is consumed by the instant heater 120, the power consumption of the storage heater 110 is ceased. Alternatively, the storage heater 110 and the instant heater 120 may be turned on together where necessary. As will be shown in the examples below, such a configuration of the water heating system 100 allows savings in the total energy consumption, lower instantaneous power requirement and lower power consumption as compared to conventional water heaters, e.g. storage water heaters or instant water heaters. Specifically, compared to a conventional water heater, the water heating system 100 reduces overall energy/power consumption needed for a typical shower duration at the user’s desired water temperature. Further, the water heating system 100 reduces the requirement for high powered input at any time while maintaining high flow rate and at the desired temperature. Also, the water heating system 100 reduces the wait time to achieve the user’s desired water temperature as will be explained later.

[0039] Fig. 2 shows a method 1000 of heating and dispensing water based on the water heating system 200 of Fig. 1. In step 1200, the method 1000 includes heating a water volume and dispensing the water volume as a first water flow. In step 1200, the method further includes heating a second water flow instantly and dispensing the second water flow. In step 1300, the method includes receiving and dispensing the first water flow or the second water flow or a mixture of the first water flow and the second water flow. [0040] Fig. 3 shows an exemplary embodiment of the water heating system 200. As shown in Fig. 3, the water heating system 200 may include a storage heater 210 and an instant heater 220. Storage heater 210 may include a storage tank 210T for storing water, a heating element 210H for heating the water therein, a first inlet 214 for channelling water into the storage tank 210T, a first outlet 212 for channelling the water out from the storage tank 210T. Heating element 21 OH may extend from a bottom portion at a bottom end of the storage tank 210T longitudinally upward towards a top portion at a top end that is opposite the bottom end of the storage tank 210T. Heating element 21 OH may extend from the bottom end to the top end of the storage tank 210T. As shown in Fig. 3, the heating element 21 OH may extend throughout the height of the storage tank 210T so that it is possible to heat the water volume throughout the storage tank 210T or any portion of water volume within the storage tank 210T. Heating element 210H may extend about three quarter height of the storage tank 210T. First inlet 214 may be disposed at about the bottom portion or the top portion of the storage tank 210T. First outlet 212 may be disposed at about the bottom portion of the storage tank 210T to allow the water volume within the storage heater 210 to be emptied without a pump, i.e. under gravity.

[0041] Storage heater 210 may include a storage tank inlet water flow sensor 210F disposed along the first inlet 214 for detecting the flow rate of the first water flow entering the storage heater 210, at least one of an inlet valve 210V disposed along the first inlet 214 for controlling the inflow of the first water flow entering the storage heater 210, an outlet valve 210W disposed along the first outlet 212 for controlling the outflow of the first water flow out of the storage heater 210, a stirrer 21 OS adapted to stir the water volume in the storage heater 210 for circulating the heated water within the storage heater 210, an anti-corrosion anode 210A for preventing corrosion of the storage tank 210T, at least one heat sensor 210TS disposed at the storage tank 210T for sensing the temperature of the water volume, a pressure relief valve 21 OP for controlling the pressure in the storage tank 210T and a drain valve 210D disposed at about the bottom portion of the storage tank 210T for draining the water volume from the storage tank 210T if need be. Storage heater 210 may include at least one heat sensor 210T each at about the top and bottom portions of the storage tank 210T. Heat sensor 210TS may include a thermostat sensor, a temperature sensor, etc. Stirrer 210S may include a propeller, a fan-like mechanism or any device to stir the water volume to circulate the heated water more evenly throughout the storage tank 210T. By circulating heated water, the time required to heat the water volume may be decreased. Heating system 200 may be configured to turn the inlet valve 210V on to allow the inflow of the first water flow into the storage tank 210T and the outlet valve 210W off to allow the storage tank 210T to be filled. Heating system 200 may be configured to turn the inlet valve 210V off to cease the inflow of the first water flow into the storage tank 210T when the outlet valve 210W is turned on to allow the first water flow to exit the storage tank 210T. The configuration of the storage heater 210T allows the heated water volume in the storage heater 210 to be emptied without inflow of first water flow into the storage heater 210. In this way, the heated water volume would not be cooled by inflow of cool first water flow, especially when the storage heater is turned off.

[0042] Storage heater 210 may include a pressure equalizer 210E for equalizing the pressure within the storage tank 210T. Pressure equalizer 210E may be disposed at the top portion of the storage tank 210T. Pressure equalizer 210E may be disposed at the top of the storage tank 210T. Pressure equalizer 210E may be connected, mechanically or electronically, to at least one of the inlet valve 210V, one or more of the flow sensors 210F, the outlet valve 201W and the dispensing valve 260. Pressure equalizer 210E may be adapted to prevent a vacuum build up and/or to prevent high pressure build up within the storage tank 210T. When the pressure within the storage tank 210T is not equalized with the pressure outside the storage tank, the flow rate of the first water flow may be affected, hence affecting the performance of the storage heater 210. Pressure equalizer 210E may be in operation, i.e. adapted to equalize the pressure within the storage tank 210T, when the outlet valve 201W is opened to let the water volume out of the storage tank 210T. At the same time, the inlet valve 210V may be shut to prevent the water from entering the storage tank 210 so that the water volume would not be mixed and cooled by the incoming first water flow. When the inlet valve 210V is opened to allow first water flow into the storage tank 210T, the pressure equalizer 210E may be in operation to allow pressure within the storage tank 210T to be released so that the flow rate of the incoming water is not reduced. Pressure equalizer 210E may include a switch, a floating ball valve, ball valve, a one-way valve, e.g. check valve, etc. As shown above, the pressure equalizer 210E may be adapted to allow fluid flow, i.e. air or water flow, into and out of the storage tank 210T. As such, the pressure equalizer 201E may include two one-way valves in opposite“direction” to allow fluid into and released from the storage tank 210. [0043] Storage heater 210 may have a capacity of 0.5 to 500 litres. Preferably, the storage heater 210 may have a capacity of 0.5 to 20 litres. Preferably, the storage heater 210 may have a small volume, e.g. a capacity of 5 litres or less, e.g. 5 litres, 4 litres, 3 litres, 2 litres, 1 litre. Storage heater 210 may have a power input in the range 0. lkW to 20kW. Preferably, the storage heater 210 may have a power input in the range of O. lkW to 4.5kW. Preferably, the storage heater 210 may have a power input in the range of 0.2kW to 3.5kW. Preferably, the storage heater 210 may have a power input in the range of 3kW to 4.5kW. Preferably, the storage heater 210 may have a power input in the range of O. lkW to 1.5kW. Preferably, the storage heater 210 may have a power input in the range of 0.2kW to 1.5kW. Preferably, the storage heater 210 may have a power input of 1.5kW. Preferably, the storage heater 210 may have a power input of 0.4kW. Storage heater 210 may heat the water volume from 30°C to 200°C. Preferably, the storage heater 210 may heat the water volume from 30°C to 80°C. Preferably, the storage heater 210 may heat the water volume from 50°C to 75°C. Preferably, the storage heater 210 may heat the water volume to 80°C, 75°C or 60°C.

[0044] Instant heater 220 may include a holding tank 220T for holding the second water flow to allow the water to be heated before exiting, a heating element 220H for heating the second water flow therein, a second inlet 224 disposed at about the bottom portion of the holding tank 220T for channelling water into the holding tank 220T, the second outlet 222 may extend from the bottom portion of the holding tank 220T and disposed at about the top portion of the holding tank 220T for channelling the water out from the holding tank 220T at the top portion. In this way, the colder inflow of the second water flow would be at the bottom portion while the hotter second water flow that has been heated is maintained at the top portion of the holding tank to be discharged. Second outlet 222 may be disposed at the bottom portion of the holding tank 220T. Instant heater 220 may include a holding tank inlet water flow sensor 220F for detecting the flow rate of the second water flow entering the instant heater 220, and a pressure relief valve 220P for controlling the pressure in the holding tank 220T. Instant heater 220 may have a power input in the range of 0. lkW to 20kW. Preferably, the instant heater 220 has a power input of less than 18kW. Preferably, the instant heater 220 has a power input of less than 3kW. Preferably, the instant heater 220 has a power input in the range of 0.2kW to 3.5kW. Preferably, the instant heater 220 has a power input in the range of 0.2kW to 1.5kW. Preferably, the instant heater 220 has a power input in the range of O. lkW to 1.5kW. Preferably, the instant heater 220 has a power input of 0.95kW. Preferably, the instant heater 220 has a power input of

0.4kW.

[0045] Water heating system 200 may include the main inlet 234 connected to and in fluid communication with the first inlet 214 and the second inlet 224. Main inlet 234 may be adapted to channel water into the water heating system 200 and into the storage heater 210 and the instant heater 220. Main inlet 234 may be connected to a water supply (not shown in Fig. 3). Water heating system 200 may include a dispensing outlet 232 connected to and in fluid communication with the first outlet 212 and the second outlet 222. Dispensing outlet 232 may be adapted to channel water out of the water heating system 200. Water heating system 200 may include a mixer 240 disposed before the dispensing outlet 232, such that the mixer 240 may be adapted to mix the first water flow and the second water flow before dispensing the mixed water flow from the water heating system 200.

[0046] The ratio of the mixture can be derived from the equation below: where r = total parts of fluid mass,

s = storage heater heated temperature (30.0-100.0°C),

d = desired output temperature (30.0-75.0°C), and

w = water supply temperature (1.0-29.9°C)

c = specific heat capacity of fluid

Based on the values above, the value of‘r’ ranges from 1-701.

Since‘r’ is the total parts of fluid mass, the ratio of mixture may range from 1 :0 to

1:700.

[0047] Mixer 240 may be configured to mix the first water flow and the second water flow in a ratio from 1:0 to 1:700. Preferably, the mixer 240 may be configured to mix the first water flow and the second water flow in a ratio from 1:0 to 1:200. Preferably, the mixer 240 may be configured to mix the first water flow and the second water flow in a ratio from 1:0 to 1:70. Preferably, the mixer 240 may be configured to mix the first water flow and the second water flow in a ratio from 1:0 to 1:8. Preferably, the mixer 240 may be configured to mix the first water flow and the second water flow in one of ratios of 1:4, 1:5, 1:6 and 1:7. Alternatively, the mixer 240 may not need to mix the water flows if it receives only the first water flow when the second water flow is ceased or vice versa. Water heating system 200 may include a dispensing valve 260 before the dispensing outlet 232 for controlling the dispensing of the heated water. Dispensing outlet 232 may be connected to a dispenser (not shown in Fig. 3), e.g. a tap, a shower head, etc.

[0048] Water heating system 200 may include a controller 250 connected to at least one of the heating element 210H, the heating element 220H, the storage tank inlet water flow sensor 210F, the inlet valve 210V, the outlet valve 210the stirrer 21 OS, the holding tank inlet water flow sensor 220F, the pressure equalizer 210E and the heat sensors 210TS. The controller 250 may be configured to receive signals from the flow sensors 210F,220F and heat sensors 210TS and transmit signals to the heating elements 210H,220H. Upon activating the water heating system 200, the controller 250 may activate the heating element 210H in the storage heater 210 to commence heating the water volume therein. Controller 250 may actuate the stirrer 210S to circulate the heated water throughout the storage tank 210T to shorten the time required to heat the water volume. Controller 250 may receive the temperature of the water volume from the heat sensor 210TS and turn off the heating element 21 OH once the temperature of the water volume reaches a pre-determined temperature as mentioned above, e.g. 75°C. When the user uses the water heating system 200 to dispense heated water, the controller 250 may detect the flow of the second water flow via the flow sensor 220F and turn off the heating element 210H of the storage heater 210 to cease the heating of the water volume therein and turn on the heating element 220H. In addition, the controller 250 may close the inlet valve 210V to cease the inflow of the first water flow into the storage heater 210 so as to cease inflow of cold water thereinto to prevent a drop in the temperature of the water volume in the storage heater 210. The water volume may be dispensed until the storage heater 210 is emptied. Depending on the required temperature of the dispensed water, the first water flow and the second water flow may be mixed in a pre-determined ratio by the mixer 240. Mixer 240 may be connected to the controller 250. Controller 250 may be configured to control the mixing ratio according to the temperature of the dispense water required according to the pre-installed programs or a user- controlled configuration. [0049] Storage heater 210 and the instant heater 220 may be a unitary body where the storage heater 210 may be in contact with the instant heater 220. Storage heater 210 may be insulated from the instant heater 220 to prevent heat transfer between each other.

[0050] The following example shows the configuration of a conventional water heater used for an activity, for example, a user taking a shower for about 8 minutes at a flow rate of 3-7 litres/min with a supply water temperature of 28°C. A conventional storage water heater may heat the water therein to a temperature of about 75°C. The conventional storage water heater 210 may be of the size of 35 litres. If the conventional storage water heater is configured to operate at a power of 1.5kW for 28 mins (20 mins heating, 8 mins shower), the total power consumption would be about 0.7kW. If the conventional storage water heater operates at a power of 0.2kW per hour for 24 hours, the total power consumption would be about 0.8kW per shower. For a conventional instant water heater, if it operates at a power of 3-4.5kW per hour, the average total power consumption of the instant heater 220 may be about 0.4-0.6kW.

[0051] The following example shows the configuration of the water heating system 200 based on the water requirement in the earlier example. While the example in Fig. 3 is used, the following examples may be used for the water heating system 100 in Fig. 1. For this example, a small volume storage heater 210, e.g. 5 litres, is used and the average flow rate of the dispensed water is 5 litre/min. In this example, the storage heater 210 may be configured to operate in the range of 0.2kW to 1.5kW per hour and the instant heater 220 may be configured to operate at less than 3kW. Storage heater 210 may heat the water volume to a temperature of 75°C as well although the range of the storage heater 210 may be from 30-200°C. The total power consumption of the storage heater 210 may be less than 0.7kW and the average total power consumption may be less than 0.4kW. In all, the water heating system 200 operates at a power of less than 1.5kW and the total power consumption per shower is less than 0.4kW. In this example, the power of the heating element 21 OH of the storage heater 210 and the heating element 220H of the instant heater 220 may be about 0.1-1.5kW. As shown, based on the same temperature in the storage heater 210, the water heating system 200 operates at a lower power input and uses less power than a conventional storage water heater. Compared to the conventional instant water heater, the power input and the power consumption of the water heating system 200 are lower. [0052] In another example where the temperature of the water supply is lower, e.g. at about 10°C, e.g. in a cold country, and the same activity, i.e. bathing, is carried out, i.e. dispense water for about 8 minutes at a flow rate of 3-7 litres/min, a conventional storage water heater that heats the water therein to a temperature of about 75°C may be configured to operate at a power of 3-4kW for 28 mins (20 mins heating, 8 mins shower) may consume a total power consumption of about 1.4-2. lkW. For a conventional instant water heater, if it operates at a power of 18-20kW per hour, the average total power consumption of the conventional instant water heater may be about 2.4-2.7kW.

[0053] In the same situation, based on the same configuration as the water heating system 200 in the previous example, i.e. the average flow rate of about 5 litres/min and duration of water dispensing is about 8 mins, the water heating system 200 may consume less power than the conventional water heater. The storage heater 210, which may have a relatively small volume, e.g. 5 litres, and may have the same average flow rate of the dispensed water of 5 litre/min, may be configured to operate between 3-4.5kW per hour for a varying period of time. The instant heater 220 may be configured to operate at less than 18kW. The total power consumption of the storage heater 210 may be less than 1.4kW and the average total power consumption may be less than 2.4kW. In all, the water heating system 200 may operate at a power of less than 3kW and the total power consumption per shower may be less than 1.4kW. In this example, the power of the heating element 21 OH or the storage heater 210 and the heating element 220H of the instant heater 220 may be about 0.1-3kW.

[0054] As clearly shown, compared to a conventional water heater, based on similar requirements, the water heating system 200 may reduce the overall energy/power consumption needed for a typical shower duration by up to 50%, reduce power input by up to 45%, reduces heating waiting time by up to 50%. In this way, the water heating system 200 may be used in countries with inconsistent or poor power supply country and be able to provide users with heated water for long period activities, e.g. bathing. For the other countries with regular power supply, the time taken to heat up the water heating system 200 for use is much shorter compared to a conventional storage water heater. [0055] The following shows another example of the configuration of the water heating system 200 having a flow rate of about 5 litres/min for about 8 mins. Storage heater 210 may have a size of 5 litres may operate at about 0.4kW for about 41mins. Instant heater 220 may operate at about 0.4kW for about 8 minutes. The mixing ratio between the first water flow of the storage heater 210 and the second water flow of the instant heater 220 may be about 1:7. Based on the configuration, the power consumption of the storage heater 210 and the instant heater 220 is 0.273kW and 0.53kW respectively. Accordingly, the total power consumption is about 0.326kW. The temperature of the dispensing water from the water heating system 200 may be about 34.8°C. Based on the above configuration, compared to a conventional water heater, there may be a savings of about 18.5% of power consumption.

[0056] The following shows another example of the configuration of the water heating system 200 which may have a flow rate of about 5 litres/min for about 8 mins. Storage heater 210 may have a size of 5 litres and may operate at about 1.5kW for about l lmins. Instant heater 220 may operate at about 0.95kW for about 8 minutes. The mixing ratio between the first water flow of the storage heater 210 and the second water flow of the instant heater 220 may be about 1:7. Based on the configuration, the power consumption of the storage heater 210 and the instant heater 220 is 0.275kW and 0.127kW respectively. Accordingly, the total power consumption is about 0.402kW. The temperature of the dispensing water from the water heating system 200 may be about 35.5°C. Preferably, the maximum power for the instant heater 220 is 0.95kW.

[0057] As the power of the storage heater 210 increases, the time taken to heat the water volume is reduced. The following table shows the relationship between the power of the storage heater 210 and the time taken to heat the water volume from 28°C to 75°C.

[0058]

[0059] As the power of the instant heater 220 increases, the temperature of the second water flow increases. Assuming a flow rate of 5 litres/min and a heating container of 350ml in the instant heater 220, the duration of the second water flow in the tank may be about 4.2s. The following table shows the relationship between the power input of the instant heater 220 and the temperature increase. The increase is about 0.29°C for every 100W increase.

[0060]

[0061] The following example shows the effect of the increase in the power of the instant heater 220 on the water heating system 200. In the example, the storage heater 210 may be configured to be a 5 litre and may have a flow rate of 5 litres/min. The temperature of the water supply for the storage tank may be at 28°C and the water volume in the storage heater 210 may be heated to about 75°C. The power of the instant heater 220 (IT) and its temperature output will be shown. Based on the temperature of the first water flow and the second water flow, the temperature of the dispensed water from the water heating system 200 may be obtained. As the water heating system 200 is configured to mix the first water flow and the second water flow, the temperature of the dispensed water may change depending on the ratio of the first water flow and the second water flow. The following example also shows various possibilities of the temperature of the dispensed water based on the mixing ratio.

[0062]

[0063] As shown above, based on a fixed storage heater 210 configuration, the power of the instant heater 220 and the mixing ratio of the first water flow and the second water flow may be changed to obtain the desired temperature of the dispensed water. For example, to achieve a dispensed temperature of 39°C, the ratio of the first water flow and the second water flow may be varied to achieve the desired temperature. In addition, the input power of instant heater 220 may be varied to achieve the desired temperature. In addition, the configuration, e.g. the power input, the storage volume of the storage heater 210 may be changed to suit the requirement. Depending on the environment that the water heating system 200 is being installed, e.g. insufficient power supply, the water heating system 200 is able to provide heated water at low power with a low power consumption for a pre-determined period of time. The water heating system 200 is able to dispense a heated water supply at a desired temperature with a storage heater of a small water capacity. Consequently, the time required to heat the water volume in the small volume storage water is shorter.

[0064] A skilled person would appreciate that the features described in one example may not be restricted to that example and may be combined with any one of the other examples.

[0065] In the following examples, reference will be made to the figures, in which identical features are designated with like numerals. [0066] The present invention relates to a water heating system and a method of heating and dispensing water generally as herein described, with reference to and/or illustrated in the accompanying drawings.