WO2005058747A2

WO2005058747A2 - Beverage dispensing system with adaptive energy management

Info

Publication number: WO2005058747A2
Application number: PCT/GB2004/005236
Authority: WO
Inventors: John Cooke; David Paul Knowles; Nick Simon Tanner; Paul Robert Fletcher
Original assignee: Mars, Incorporated
Priority date: 2003-12-15
Filing date: 2004-12-15
Publication date: 2005-06-30
Also published as: GB2409197A; WO2005058747A3; GB0613938D0; GB0329015D0; GB2425300A; GB2425300B

Abstract

A beverage dispensing system for preparing and dispensing beverage portions in response to an operator instruction, the system comprising: a control system including an operator interface for inputting beverage dispensing instructions; a beverage making apparatus for making a beverage in response to a command from the control system; and a water supply apparatus for providing water to the beverage making apparatus at a beverage preparation temperature above or below ambient temperature, said water supply apparatus comprising a water heating or cooling apparatus having a plurality of heating or cooling power modes, said plurality of power modes having different levels of power consumption for heating or cooling; and said control system being adapted to calculate a frequency of said dispensing instructions received, and to switch the water heating or cooling apparatus between a lower and a higher power mode in accordance with the frequency of operator instructions. Also provided is a water supply apparatus for use in such beverage dispensing systems, and methods of operation of such water supply apparatus.

Description

BEVERAGE DISPENSING SYSTEM WITH ADAPTIVE ENERGY MANAGEMENT

The present invention relates to a beverage dispensing system incorporating a programmable control system and to a water supply apparatus for such a system.

A beverage dispensing system is required to be capable of dispensing drinks immediately on demand and so, in order to ensure this, the system will ordinarily maintain a tank of water at beverage-serving temperature whenever it is operational. However, the frequency of beverage preparation is unlikely to be uniform over time - for example, a vending machine in an office environment will clearly experience a much greater frequency of use during working hours than outside them, hence there are times when more water is being maintained at beverage temperature than is needed for beverage preparation.

Constantly maintaining the water tank at beverage temperature represents a significant running cost of the dispensing system so it would clearly be desirable to find a more energy-efficient way to supply the smaller quantities of water at beverage temperature that are required during periods of low demand.

In a first aspect, the present invention provides beverage dispensing system for preparing and dispensing beverage portions in response to an operator instruction. The system comprises a control system including an operator interface for inputting beverage dispensing instructions, a beverage making apparatus for making a beverage in response to a command from the control system, and a water supply apparatus for providing water to the beverage making apparatus at a beverage preparation temperature above or below ambient temperature. The water supply apparatus comprises a water heating or cooling apparatus having a plurality of heating or cooling power modes, said plurality of power modes having different levels of power consumption for heating or cooling. The control system comprises a clock, and the control system is adapted to determine the time of each dispensing instruction and to calculate a frequency of said instructions received, and to switch the water heating or cooling apparatus between a lower and a higher power mode in accordance with the frequency of operator instructions.

The system can operate in a preprogrammed mode and/or a predictive (self- learning) mode and/or in a reactive mode. In the preprogrammed mode, the control system is programmed to default power modes at predetermined times of the day. For example, the control system may be adapted to switch the system to a low power mode during certain hours of the day or night. In certain embodiments, the system incorporates and ambient light sensor, and the system defaults to a low power mode when ambient light falls below a predetermined level.

In the predictive (self-learning) mode, the control system calculates and stores a mean value of the frequency of the operator instructions in respect of a predetermined time period during a day, and the control system is adapted to switch the system to a predicted power mode at the beginning of each time period for which the calculated and stored mean frequency of dispensing instructions is within a predetermined frequency range for said predicted power mode. In other words, the frequency of instructions expected in a given time period (e.g. 10.00am to 11.00am on a Monday) is predicted, based on the average number of instructions measured in one or more previous such time periods, and the system is switched to an appropriate power mode for that frequency of instructions at the outset of the time period (or shortly before the start of the time period in order to allow time for pre-heating of the water, as discussed further below).

In the reactive mode, the control system switches the system to higher or lower power mode if the measured frequency of dispensing instructions received while the system is in a given power mode falls respectively above or below an appropriate frequency range for the given power mode. For example, the system may initially default to the programmed or predicted power mode as described above, but the system can further react to switch to a more suitable power mode if the actual frequency of instructions is above or below what was programmed or predicted. For example, the system may calculate the actual frequency of instructions my measuring the time taken to receive a number n (e.g. 3, 5, 10 or 20) consecutive instructions, and then adjust the power mode to a more suitable power mode if the actual frequency of instructions is above or below what is optimum for the current power mode. This process may be carried out continuously, for example the system may calculate a rolling average frequency f between instructions by measuring the time t taken to receive the preceding n instructions wherein f=n/t. The power mode may thereby be optimised after each beverage making instruction by adjusting the power mode to a more suitable power mode if the rolling frequency of instructions is above or below what is optimum for the current power mode.

Suitably, the system has at least three power modes, and in certain embodiments the power consumption of the heating or cooling system is substantially continuously variable over at least part of the range between a maximum power mode and a minimum power mode. This can be achieved for example by having a system adapted to maintain water in a tank at a range of temperatures intermediate ambient temperature and a beverage preparation temperature.

The beverage making apparatus in the system according to the present invention is typically a system for the preparation of hot beverages, such as hot tea, hot coffee, hot soup or hot chocolate. In such systems, the beverage preparation temperature is suitably from 80°C to 105°C, for example from about 85°C to about 99°C. Alternatively or additionally, the system may be adapted for the preparation of cold beverages, for example by dilution of beverage concentrates (solid or liquid) with cold water. In such systems, the beverage preparation temperature is suitably from about 0°C to about 10°C, for example from about 2°C to about 8°C.

The beverage making machine may be fully automatic, or semi-automatic. The term semi-automatic refers to machines that are adapted to prepare a beverage from a pack containing a beverage ingredient that has been selected by an operator from a range of different packs, for example a pack taken from a display rack adjacent to the machine. The operator inserts the pack into a beverage making station of the machine, and the machine then prepares a beverage from the pack, usually by injecting water into the pack and extracting the prepared beverage through one or more outlets in the pack. Such machines can sometimes prepare a range of different beverages, for example coffee, tea, soup, chocolate, or flavored cold drinks. Beverage packs for use in machines of this type are described, for example in WO94/01344, EP-A-0512468 and EP-A-0468079 (all Nestle), in US-A-5840189 (Keurig), in EP-A-0272922 (Kenco), and in EP-A- 0179641 and WO02/19875 (Mars), the entire contents of which are incorporated herein by reference. In the fully automatic machines, the machine itself selects the pack from a stored magazine and loads it into the beverage making station in response to the operator instruction.

Also suitable for the practice of the present invention are in-cup beverage dispensing devices, such as those available from Mars Incorporated under the Registered Trade Mark KLIX. In-cup vending systems are based on stacks of disposable cups, each containing a portion of beverage making ingredients in its base. The cups are snap-fitted together in the stack, and the stack is then packaged, stored and transported conveniently by the vending operator. In use, the stack is removed from its packaging and loaded into the dispenser of a vending machine. In response to a vending command, the machine automatically splits a cup from the bottom of the stack and fills it with hot or cold water to form the desired beverage. Most in-cup beverage dispensing apparatus contain a number of cup stacks, at least one such stack being provided for each beverage supplied by the apparatus. In such machines, the plurality of cup stacks are usually arranged in a carousel, so that rotating the carousel brings the desired cup stack to a dispensing position.

In certain embodiments of the present invention, the water supply apparatus comprises one or more water tanks together containing sufficient water for a plurality of beverage portions, and all of the water tanks are continuously maintained at a beverage preparation temperature only when the system is in the highest power mode. In this and other embodiments, the water supply apparatus may further comprise at least one fast water heating or cooling device to supply water at the beverage temperature on an 'on demand' basis when the system is in a lower power mode. Suitable fast heating or cooling devices include a hot or cold block having a channel therethrough for the water, or a small tank with suitable heating or cooling means. The heating or cooling means may include conventional resistive heating, Peltier effect heating or cooling, or heating or cooling that makes use of the latent heat of a phase change in a suitable material. The fast heating or cooling element preferably heats or cools only the volume of water actually used to prepare the beverage.

In certain embodiments of this invention, the apparatus comprises a segmented water tank having first and second volumes containing water maintained at first and second temperatures. One apparatus of this type is described in W098/31266. The tank is divided into a water reservoir to receive cold water, and a smaller heating chamber at the bottom to dispense hot water. The reservoir and chamber are divided by, for example, a baffle. The baffle may comprise one or more orifices for fluid communication, or there may be gaps between the baffle and the tank wall to permit fluid communication without excessive convective heat exchange. The baffle can be a wall in a container dividing the chamber from the reservoir. The orifices may be provided with one-way valves or pressure release valves as described in W098/31266.

A tight fit between the baffle and the tank wall is not needed in order substantially to restrict the convective circulation of the water in the tank. Indeed, in certain embodiments in which the water is maintained at a higher temperature in an upper region of the tank, there is minimal convective mixing and the baffle may be dispensed with entirely.

In certain embodiments, the dividing wall (baffle) is movable to vary the relative sizes of the first and second volumes within the segmented water tank. There are many alternative methods known to those skilled in the art in which the baffle could be moved. For example, the dividing wall may be mounted on a threaded rod that extends axially in the tank and that can be rotated by a suitable gear and motor.

In certain embodiments, the dividing wall is a floating divider having a density intermediate the densities of water at the beverage preparation temperature and water at ambient temperature. For example, the density of pure water at 20°C is 0.998g/cm³, the density of water at 95°C is 0.963g/cm³. So for a hot water system the floating divider (baffle) could have a density of from about 0.97 g/cm³ to 0.99 g/cm³,suitably about 0.98g/cm³ for example it could be formed of a polyethylene having density in this range.

Suitably the system comprises a thermometer to measure the temperature of the water in a tank or tank section, optionally in more than one tank or tank section. In certain embodiments the system is adapted to measure and record the amount of time required to heat or cool the water in the said tank or tank section to a predetermined beverage preparation (dispensing) temperature. The system may use this information, for example when switching to a higher power mode in preprogrammed or predetermined (self-learning mode), the power may be increased a sufficient time before the set time for the start of the time period to allow the water tank to heat up. The time required for pre-heating of the water will depend on the initial temperature of the water, the ambient temperature, and other factors such as the amount of scale formation on the heating element. For this reason the control system preferable comprises a self-learning feature whereby the time needed to switch between modes is calculated and stored.

In a further aspect, the present invention provides a water supply apparatus and associated control system suitable for use in a beverage dispensing system according to the present invention. The features of the water supply system and the control system are as described hereinbefore in relation to the first aspect of the invention.

In a further aspect, the present invention provides a water supply apparatus suitable for use in a beverage dispensing system according to the present invention. The features of the water supply apparatus are as described hereinbefore in relation to the first aspect of the invention.

In a further aspect, the present invention provides a water supply apparatus suitable for use in a beverage dispensing system according to the present invention, wherein the water supply apparatus comprises a segmented water tank having first and second volumes separated by a dividing baffle, wherein the dividing baffle is movable to vary the relative sizes of the first and second volumes within said segmented water tank.

The preferred features of the water supply system are as described hereinbefore in relation to the first aspect of the invention. For example, the dividing wall may be a floating divider having a density intermediate the densities of water at the beverage preparation temperature and water at ambient temperature.

In a further aspect, the present invention provides a method of operating a water supply apparatus and associated control system suitable for providing water to the beverage making apparatus in a beverage dispensing system for preparing and dispensing beverage portions in response to an operator instruction, the control system including an operator interface for inputting beverage dispensing instructions; and said water supply apparatus comprising a water heating or cooling apparatus having a plurality of heating or cooling power modes, said plurality of power modes having different levels of power consumption for heating or cooling; said method comprising the steps of calculating a frequency of said dispensing instructions received, and switching the water heating or cooling apparatus between a lower and a higher power mode in accordance with the said frequency of operator instructions. The preferred features of method according to the present invention are as described hereinbefore in relation to the first aspect of the invention.

Other functions, including the illumination of the machine and components of the user interface, may be de-activated in certain low-power modes to further conserve energy. By limiting the functions performed by the dispensing system when demand for its services is low then reverting to the normal high power mode when there is an increased demand for beverages, the control system reduces its overall power consumption.

Specific embodiments of the present invention will now be described further, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows the logic that determines the power mode of an embodiment of the system operating in the predictive (self-learning) mode; Figure 2 shows a partial schematic diagram of a beverage making system according to a first embodiment of the present invention;

Figure 3 shows a partial schematic diagram of a beverage making system according to a second embodiment of the present invention; and Figure 4 shows a partial schematic diagram of a beverage making system according to a third embodiment of the present invention.

Referring to Fig. 1, the control system is programmed to divide the week into consecutive one-hour time periods. At the start of each time period, the system defaults to a stored optimum power mode for that period. (At the initial start-up of the system this would have to be a preprogrammed mode, or possibly default to maximum power mode). The system receives instructions and prepares beverages for the duration of the one-hour period, and at the end of the period the actual mean frequency of beverage making instructions during the period is calculated. This actual mean frequency is stored and used to update the stored optimum power mode for the period. For example, a rolling average of actual mean frequencies over the preceding N (e.g. N=2, 3, 5 or 10) such time periods could be used to predict the optimum power mode for the period.

Referring to Figure 2, the apparatus comprises a stand 2 for a cup 3 to receive a beverage made by the system. The system further comprises apparatus for supplying hot water, and apparatus for preparing a beverage from the hot water. The apparatus for preparing a beverage from the hot water is substantially as described and claimed in GB-A-2121762 and EP-A-0179641 , the entire contents of which are incorporated herein by reference. Systems of this general type are also commercially available from Mars, Incorporated under the registered trade mark FLAVIA. Briefly, the apparatus for preparing a beverage comprises a sachet 4 containing a beverage-brewing ingredient such as ground coffee or leaf tea retained by a suitable filter paper. The sachet is formed by bonding together front and back faces of flexible, plastic laminate around side margin 5, a bottom margin 6 and top margin 7. A molded thermoplastic inlet nozzle 8 is inserted into the top margin 7 of the sachet, and the inlet nozzle 8 is sealed before use by a frangible freshness barrier. The bottom margin 6 of the sachet is sealed by a heat-sensitive or pressure-sensitive adhesive that permits the bottom of the sachet to peel open when hot water is injected into the sachet to brew the beverage in the sachet. The beverage brewed in the sachet then flows out of the bottom of the sachet into the cup 3.

The beverage making apparatus according to this embodiment further comprises a clamp 9 adapted to grip the flanged inlet nozzle 8 of the sachet 4 during beverage preparation. The beverage making apparatus further comprises an injector tube 10 that can be inserted into the nozzle 8 of the sachet 4 to penetrate the freshness barrier for injection of the hot water into the sachet for beverage preparation. At least part of the injection tube 10 is dimensioned to form a substantially air-and water-tight fit inside the bore of the inlet nozzle 8. The clamp 9 and/or the injection nozzle 10 are reciprocally movable to achieve insertion of the injector tube 10 into the nozzle 8. This reciprocating motion may be driven by a servo motor through a suitable mechanism, or it maybe driven through a suitable linkage to a manually operated lever, or to an operator function such as closing a door of a compartment in the apparatus.

Referring now to the apparatus for supplying hot water, in this embodiment it comprises a main water tank 12 containing sufficient water for preparation of at least five individual beverage portions, and a small hot water tank 14 containing sufficient hot water for preparation of only two individual beverage portions, i.e. a maximum volume of about 400ml. It will be appreciated that in alternative embodiments there could be more tanks of varying sizes, or even a number of small tanks having a similar total volume.

Each hot water tank 12,14 is provided with a respective resistive heating element 16,18. It will be appreciated that in alternative embodiments for the preparation of chilled drinks, the heating elements 16,18 maybe replaced by appropriate cooling elements, for example Peltier effect cooling devices. The small hot water tank 14 is gravity fed with water from the large hot water tank 12 through control valve 20. Hot water tanks 12,14 are equipped with respective thermocouple temperature sensors 22,24. Large hot water tank 12 is fed with water supplied from a suitable outside source through control valve 26, and a maximum water level in large tank 12 is monitored by level sensor 28. Hot water from small tank 14 is pumped to injector 10 by hot water pump 30. Pump 30 is suitably adapted to supply water to the injector 10 at a pressure of approximately 1 bar gauge. Finally, the system comprises an air pump 32 that pumps air through injector 10 into sachet 4 as the end of the beverage preparation cycle in order to de-water the sachet.

Valves 20, 26, 30 and 32, heating elements 16, 18 and the device for reciprocating the injector 10 relative to clamp 9 are all controlled by a single digital control system 34. The system 34 is connected to the operator input panel 35, which is typically a soft key console for selection of beverages. The output of temperature sensors 22 and 24 is also received by the control system 34. In use, the system can be operated in a high power mode, in which heating elements 16 and 18 are used to maintain the water in both the large tank 12 and the small tank 14 at the beverage making temperature, typically 90 to 95°C. The system may also be operated in a low power mode, wherein heating element 16 is not energised to heat the water in tank 12, but heating element 18 is used to maintain the water in tank 14 at a beverage brewing temperature of 90 to 95°C. It is also possible to operate the system in a third, very low power mode, wherein neither of the heating elements 16, 18 is energised. It is still possible to prepare a beverage in a fairly short time starting from the very low power mode, because the small volume of tank 14 permits the water therein to be brought up to a beverage brewing temperature quickly following receipt of a beverage making instruction. It will also be appreciated that the system of Figure 2 can be operated in a range of power modes intermediate the low power mode and the very low power mode, each intermediate mode being characterised by maintaining the water in small tank 14 at a different temperature intermediate the ambient temperature and the beverage brewing temperature and/or by only partially filling the small tank 14 with water. It will further be appreciated that the system of Figure 2 can be operated in a range of power modes intermediate the low power mode and the high power mode, each intermediate mode being characterised by maintaining the water in the large tank 12 at a different temperature intermediate the ambient temperature and the beverage brewing temperature and/or by only partially filling the large tank 12 with water.

The rate at which heating elements 16, 18 respectively raise the temperature of the water in large tank 12 and the small tank 14 to the beverage brewing temperature will not be constant over time, but will be a function of ambient temperature, starting temperature and other factors such as scale formation on the heating elements. For this reason, control system 34 is further adapted to measure and store information about the rate of temperature increase measured in large and small tanks, and at least intermittently to update such information, whereby control system 34 is adapted to predict the time that it will take for a given tank to reach predetermined beverage making temperature, therefore to calculate a pre-heating interval before the programmed time for switching between modes to initiate the selective heating of the tanks.

Referring now to Figure 3, the embodiment shown therein also comprises an apparatus for preparing beverages and an apparatus for the supplying of hot water to the beverage making apparatus. The apparatus for preparing beverages is identical to that described in relation to Figure 2, and will not be described again. The apparatus for applying water comprises a single, large hot water tank 40 having a heating element 42, thermocouples 44 and 45, and fill level sensor 46. The tank 40 is supplied with cold water through valve 47 and inlet 48. Hot water is drawn off through outlet 49 situated in a lower region of the tank 40. The distinctive feature of tank 40 is that it is a segmented tank, having a low- temperature volume 50 separated from a relatively high-temperature volume 52 by a movable baffle plate 54. Baffle plate 54 can be moved up and down to vary the volumes 50, 52 by means of threaded rod 56 and gearbox mounting 57 driven by a suitable servo motor. Baffle 54 is equipped with a pressure release valve 58 to accommodate thermal expansion of the water in the high-temperature volume 52. Pressure release valve 58 allows hot water or steam from region 52 to pass into region 50 for pressure relief, as described in more detail in WO90/31266. Baffle 54 is also equipped with refill valve 59 to allow cold water from volume 50 to pass through the baffle to refill hot water region 52. However, the refill valve 59 can be dispensed with by leaving a small gap between the edges of the baffle 54 and the side walls of the tank, so long as the baffle substantially reduces convection between the upper and lower volumes.

The baffle 54 has a hollow conical shape, whereby when the baffle is fully depressed such that the bottom of the baffle contacts the bottom of the tank 40, the conical volume of water inside the baffle is a predetermined minimum volume sufficient for preparation of a single beverage portion. A similar effect could be achieved by providing a suitably shaped bottom to tank 40.

The operation of the system embodiment shown in Figure 3 is substantially as described above in relation to the embodiment of Figure 2, with the hot water volume 52 functioning as the hot water tank (element 14 of Figure 2), with the additional degree of freedom that the volume of the hot water region can be varied to increase the volume of hot water that is maintained at brewing temperature in accordance with expected or experienced demand. As before, intermediate power modes can also be realised by maintaining the water in the volume 52 at temperatures intermediate ambient temperature and the beverage preparation temperature.

Referring now to Figure 4, this embodiment comprises a hot water supply apparatus comprising a large water tank 62 that is segmented into an upper, hot water volume 64 and a lower, cold water volume 66 by a floating baffle 68 having a density intermediate the density of water at ambient temperature (say 25°C) and water at 95°C. Specifically, the floating baffle 68 is formed from a solid piece of low density polyethylene having a density of 0.98g/cm³. The baffle 68 partitions the internal volume of the tank 52, but water can still flow around the edges of the baffle between the volumes 64 and 66. The water in the upper, hot water volume 64 is actively heated by means of wall mounted heating elements (band heaters) 70, 71 and 72. The heating elements are activated depending on the ratio of volumes 64 to 66 that is desired, which in turn is determined according to the experienced or expected frequency of beverage making instructions. Hot water is drawn from the top of the tank 62 through outlet 73. Cold water is admitted into the bottom of the tank 62 through inlet 74 and valve 75.

In the high power mode, heaters 70, 71 and 72 are all energised, so that substantially the whole volume of water in the tank 62 is heated to the beverage brewing temperature of 90 to 95°C, and the baffle 68 sinks to the vicinity of the bottom of the tank 62. In an intermediate power mode, only heaters 70 and 71 are energised, and the baffle takes up a position between heaters 71 and 72, such that volume 64 is approximately twice the volume 66. In a low power mode, only heating element 70 is energised, and the baffle 68 then takes up a position intermediate heaters 70 and 71 , whereby the hot water 64 is approximately half the cold water volume 66, as shown in the drawings.

The baffle 68 helps to prevent mixing between the cold water admitted through inlet 74 and the hot water in volume 64 during dispensing of beverages. However, it will be appreciated that in certain embodiments the baffle 68 could be dispensed with entirely, since convective mixing between the upper volume 64 and lower volume 66 will be minimal.

The above embodiments have been described by way of example only. Many others examples falling within the scope of the accompanying claims will be apparent to the skilled reader.

Claims

1. A beverage dispensing system for preparing and dispensing beverage portions in response to an operator instruction, the system comprising: a control system including an operator interface for inputting beverage dispensing instructions; a beverage making apparatus for making a beverage in response to a command from the control system; and a water supply apparatus for providing water to the beverage making apparatus at a beverage preparation temperature above or below ambient temperature, said water supply apparatus comprising a water heating or cooling apparatus having a plurality of heating or cooling power modes, said plurality of power modes having different levels of power consumption for heating or cooling; and said control system being adapted to calculate a frequency of said dispensing instructions received, and to switch the water heating or cooling apparatus between a lower and a higher power mode in accordance with the frequency of operator instructions.

2. A beverage dispensing system according to claim 1, wherein the control system calculates and stores a mean value of the frequency of said operator instructions in respect of a predetermined time period during a day, and the control system is adapted to switch the system to a predicted power mode at the beginning of each time period for which the calculated mean frequency of dispensing instructions is within a predetermined frequency range for said predicted power mode.

3. A beverage dispensing system according to any preceding claim, wherein the control system switches the system to higher or lower power mode if the measured frequency of dispensing instructions received while the system is in a current power mode falls respectively above or below the optimum frequency range for said current power mode.

4. A beverage dispensing system according to any preceding claim, wherein the control system is further adapted to switch the system to a low power mode during certain hours of the day or night, or when ambient light falls below a predetermined level.

5. A beverage dispensing system according to any preceding claim, wherein the system has at least three power modes.

6. A beverage dispensing system according to any preceding claim, wherein the power consumption of said heating or cooling system is substantially continuously variable over at least part of the range between a maximum power mode and a minimum power mode.

7. A beverage dispensing system according to any preceding claim, wherein the apparatus comprises a one or more water tanks together containing sufficient water for a plurality of beverage portions, and all of the water in the water tanks is continuously maintained at a beverage preparation temperature when the system is in the highest power mode.

8. A beverage dispensing system according to any preceding claim, wherein the apparatus further comprises at least one fast water heating or cooling device, and heating or cooling of water is carried out by the fast heating or cooling device when the system is in a low power mode.

9. A beverage dispensing system according to any preceding claim, wherein the apparatus comprises a main water tank and one or more smaller water tanks, and only the water in one or more of the smaller water tanks is heated or cooled when the system not in the maximum power mode.

10. A beverage dispensing system according to any preceding claim, wherein the apparatus comprises a segmented water tank having first and second volumes separated by a divider.

11. A beverage dispensing system according to claim 10, wherein the divider is movable to vary the relative sizes of the first and second volumes within said segmented water tank.

12. A beverage dispensing system according to claim 11, wherein the divider is a floating divider having a density intermediate the densities of water at the beverage preparation temperature and water at ambient temperature.

13. A beverage dispensing system according to any of claims 1 to 6, wherein the water supply apparatus comprises a tank having an upper volume containing water at a relatively high-temperature and a lower volume contiguous with said upper volume containing water at a relatively lower temperature, wherein said volumes are optionally separated by a solid baffle.

14. A beverage dispensing system according to any preceding claim, wherein the system is adapted to maintain a volume of water in one or more of said tanks or volumes at a temperature intermediate ambient temperature and a beverage preparation temperature when the system is not in the maximum power mode.

15. A beverage dispensing system according to any preceding claim, wherein the system is adapted to maintain a volume of water partially filling one or more of said tanks or volumes at a temperature above or below ambient temperature when the system is not in the maximum power mode.

16. A beverage dispensing system according to any preceding claim, wherein the system comprises a thermometer to measure the temperature of the water in a tank or tank section, and the system is adapted to measure and store the amount of time required to heat or cool the water in the said tank or tank section to a predetermined beverage brewing temperature.

17. A^" water supply apparatus suitable for use in a beverage dispensing system according to any of claims 1 to 13, comprising a segmented water tank having first and second volumes separated by a divider, wherein the divider is movable to vary the relative sizes of the first and second volumes within said segmented water tank.

18. A water supply apparatus according to claim 17, wherein the divider is a floating divider having a density intermediate the densities of water at the beverage preparation temperature and water at ambient temperature.

19. A water supply apparatus and associated control system suitable for providing water to the beverage making apparatus in a beverage dispensing system for preparing and dispensing beverage portions in response to an operator instruction, the control system including an operator interface for inputting beverage dispensing instructions; and said water supply apparatus comprising a water heating or cooling apparatus having a plurality of heating or cooling power modes, said plurality of power modes having different levels of power consumption for heating or cooling; and said control system being adapted to calculate a frequency of said dispensing instructions received, and to switch the water heating or cooling apparatus between a lower and a higher power mode in accordance with the frequency of operator instructions.

20. A method of operating a water supply apparatus and associated control system suitable for providing water to the beverage making apparatus in a beverage dispensing system for preparing and dispensing beverage portions in response to an operator instruction, the control system including an operator interface for inputting beverage dispensing instructions; and said water supply apparatus comprising a water heating or cooling apparatus having a plurality of heating or cooling power modes, said plurality of power modes having different levels of power consumption for heating or cooling; said method comprising the steps of calculating a frequency of said dispensing instructions received, and switching the water heating or cooling apparatus between a lower and a higher power mode in accordance with the said frequency of operator instructions.