NL2014790B1

NL2014790B1 - A beverage preparation device.

Info

Publication number: NL2014790B1
Application number: NL2014790A
Authority: NL
Inventors: Edward Hoogerwerf Alexander
Original assignee: Aeh Concepts
Priority date: 2015-05-11
Filing date: 2015-05-11
Publication date: 2017-01-26
Also published as: WO2016182440A1; NL2014790A

Abstract

The invention relates to a water temperature control device for use in a beverage preparation device. The water temperature control device comprises a water reservoir for containing water for beverage preparation, a heat exchanger element for heating and/or cooling water in the water reservoir, and a cup holder for holding a cup. The cup holder includes a heat conducting element for conducting heat from water in the reservoir to a cup held by the cup holder or vice versa.

Description

P107612NL00

Title: A beverage preparation device

The invention generally relates to a water temperature control device for a beverage preparation device. The invention further relates to a beverage preparation device and to a method of preparing beverages.

Water temperature control devices are known in the art and are commonly used in beverage preparation devices, such as for instance tea or coffee brewing machines. The water temperature control devices, e.g. boilers, in these machines usually extract water from an external water supply, for example, a water reservoir or a water pipe. A known water temperature control device includes a water reservoir in which water can be stored and a heat exchanger element for controlling and/or adjusting the temperature of the water in said reservoir. Often, known water temperature devices also include a separate hot water tank in which the heated water can be stored. During use of such a known device, its water reservoir is first filled with cold water. Said reservoir is connected to a water temperature control device tank, e.g. via a number of heated tubes through which water flows. A disadvantage of the water temperature control devices known in the art is that they require a relatively high voltage, e.g. 230 Volt. Further, known beverage preparation devices provided with such a water temperature control device are often not portable. Moreover, these water temperature control devices are also not very energy efficient. Furthermore, during use of these water temperature control devices in beverage preparation devices, the prepared beverage cools down relatively quickly.

Another disadvantage is that beverage preparation devices are of complicated design. This, because the water temperature control devices require a separate water reservoir as well as a water temperature control device tank for storing heated water that has been extracted from the water reservoir. As a result, these beverage preparation devices are relatively large and not portable. In addition, known beverage preparation devices are often relatively expensive and may produce relatively a lot of disturbing noises.

The invention aims at alleviating one or more of the aforementioned disadvantages. In particular, the invention aims at providing a water temperature control device for use in a beverage preparation device, which water temperature control device is relatively energy efficient.

Thereto, the invention provides for a water temperature control device for use in a beverage preparation device, wherein the water temperature control device comprises a water reservoir for containing water for beverage preparation, a heat exchanger element for heating and/or cooling water in the water reservoir, and a cup holder for holding a cup, wherein the cup holder includes a heat conducting element for conducting heat from water in the reservoir to a cup held by the cup holder or vice versa.

By providing a water temperature control device with a cup holder which has a heat conducting element for conducting heat from water in the reservoir to a cup held by the cup holder, the water contained in the reservoir, which water can be heated or cooled by the heat exchanger element, can be used to heat or cool a beverage in a cup held in the cup holder, e.g. in order to substantially maintain a desired temperature of the beverage. For example, heat provided by the heat exchanger element may not only be used for heating the water in the reservoir, but may indirectly keep a beverage in a cup held by the cup holder at a desired temperature. This way, the beverage in the cup may be kept relatively warm for a relatively long period of time. The heat exchanger element may also be arranged to cool the water inside the water reservoir such that the beverage in the cup may be kept relatively cold for a relatively long period of time.

For instance, the water may be cooled to temperature that ranges in between 3- 10 °C, preferably about 5 °C. Since no additional heat exchanger is needed to keep the beverage at a desired temperature, the inventive water temperature control device according to an aspect of the invention can be relatively energy efficient.

Additionally, a part of the heat from the heat exchanger element may be transferred directly to the cup held by the cup holder. For example, this may be the case when the heat exchanger element is arranged on and/or near the cup holder such that it is in close contact with the cup held by the cup holder. This way, the heat exchanger element may transfer a part of the heat provided by the heat exchanger element directly to the cup, but it may also at the same time transfers a part of its heat to the water reservoir, i.e. to the water contained therein, via the reservoir wall. It is noted that, after the water contained in the reservoir has been heated by the heat exchanger element to a certain temperature, thermal energy of the water may be transferred to the cup held by the cup holder. Therefore, at least a part of the thermal energy of the water contained in the reservoir can be transferred to the cup held by the cup holder.

Additionally or alternatively, the heat exchanger element may transfer its heat indirectly to the cup held by the cup holder, e.g. via an outer surface of the water reservoir and/or via the heated beverage in the reservoir. The cup holder may comprise a receiving area for receiving a cup. Hot beverage can be poured in the cup. The receiving area may for instance be arranged on top or above the reservoir. In the reservoir, the temperature of the water may be controlled and/or adjusted by the heat exchanger element, for example to a temperature of up to 60°C - 95°C, preferably about 90 °C. By doing so, the thermal energy of the heated water in the reservoir may be transferred to the cup held by the cup holder via the heat conducting element.

The heat conducting element may comprise a thermally conductive material, e.g. a metal. The heat conducting element may extend from in the reservoir to a position located outside of the reservoir. For example, the heat conducting element may comprise plates or rods extending from the reservoir. A first end of the heat conducting element may be in contact with the water contained in the reservoir while a second end of the heat conducting element may be arranged outside the reservoir and may form at least a part of the cup holder. The heat of the water contained in the water reservoir may then be guided via the heat conducting element to the cup holder, and then to the cup that is held by the cup holder. It is noted that the plates and/or the rods extending from the reservoir does not have to enclose the circumference of the cup entirely or continuously.

The plates and/or rods may, for example, form a crown in which the cup can be held.

Preferably, the heat conducting element may be formed to extend, at least partially, along the cup held by the cup holder. This way, the heat transfer surface area may be increased and the heat of the beverage in the reservoir may be used to keep the hot beverage even longer on temperature in a more efficient way. The heat conducting element may be formed to extend, at least partially, around a side wall of the cup held by the cup holder. This way, the safety of the water temperature control device may be further enhanced. In particular, the cup of hot beverage may be tightly enclosed around its circumference by the cup holder such that the cup is secured and cannot fall down relatively easily. It is noted that the heat conducting element may comprise a retainer ring which diameter and/or circumference is substantially the same as the diameter and/or circumference of the cup held by the cup holder.

The heat conducting element may comprise a thermally conductive wall part of the cup holder. The wall part may be made from metal, e.g. aluminum. The wall part may be relatively in close contact with the cup held by the cup holder. For example, the wall part may be spaced a few mm, e.g. 2-10 mm apart from the cup.

The cup holder may define a chamber for accommodating the cup. The chamber may enclose, at least partially, the cup held by the cup holder. In particular, the compartment may enclose the bottom and/or the side wall of the cup. The inner walls of the chamber may comprise thermally conductive material, e.g. metal. The chamber may have a triangular, square, rectangle or circular cross section for receiving the cup.

Furthermore, the chamber may be tapered to accommodate a relatively stiffed cup.

The water reservoir may be part of the heat conducting element such as that the heat conducting element may be an integral part of the reservoir. The reservoir, in particular, its outer surface may be in heat exchange contact with the cup held by the cup holder such that the thermal energy from the water contained in the reservoir is transferred to the cup. The outer surface of the reservoir may be formed as part of the cup holder. This way, the water temperature control device may be of a hghter design because no additional rods and/or plates is required to transfer the thermal energy from the beverage contained in the reservoir to the cup held by the cup holder.

The water reservoir may be provided with a cavity for receiving the cup, wherein said cavity may form the cup holder. In particular, the cup holder may be sunk from the top into the reservoir. Preferably, the cup held by the cup holder is, at least partially, enclosed by the reservoir. The cavity may be separated from the water contained in the water reservoir by a reservoir wall part which may comprise the heat conducting element. Therefore, the cup is not in hquid contact with the beverage contained in the reservoir. The reservoir may be watertight and the thermal energy may be transferred towards the cup from the heated water via the reservoir wall part. The reservoir may have a U- shaped cross section and may enclose the bottom and/or the circumference of the cup held by the cup holder.

By having the cup holder sunk into the reservoir, at least partially, it may be achieved that the design of the water temperature control device may be relatively compact because the cup holder holding the cup does not extend excessively outside the contour of the reservoir.

Further, by lowering the cup holder into the reservoir, it can be counteracted that the cup tips over. Hence, the cup can does be held in a relatively stable positon, which can be relatively advantageous when the water temperature control device is used in a portable beverage preparation device.

It is noted that is also possible that the reservoir is partially enclosing and/or is partially in contact with the cup held by the cup holder.

It is noted that a retainer ring may be arranged above the cup holder and/or above the receiving area to retain the cup of hot beverage to further increase the safety.

The upper side of the cup held by the cup holder may extend a few cm, e.g. 1-3 cm, above the reservoir. This way, the user may easily pick up the cup held by the cup holder.

The water reservoir may define an inner room for accommodating the water, and wherein said inner room extends, at least partially, around a side wall of the cavity for receiving the cup. This way, heat from the water in the inner room, may be transferred relatively quickly to the cup since the heated water surrounds the side wall of the cavity.

The water reservoir may comprise a metal wall part, wherein the heat exchanger element may be placed against an outside of said metal wall part. Preferably, the metal wall part is on the outside surface of the reservoir. The metal wall part may be on a side surface of the reservoir. It is noted that it is also possible that the heat exchanger element is not in physical contact with the outer surface of the reservoir, but via an intermediate medium and/or layer. By having the heat exchanger element arranged outside the reservoir, i.e. not in contact with the water in the reservoir, scale inside the reservoir may be prevented to a certain degree. It is noted, that is also possible to have the heat exchanger element inside the reservoir in direct contact with the water.

Furthermore, it is noted that the water temperature control device according to the invention also functions as a water reservoir in which relatively cold water may be stored and is gradually being heated up by the heat exchanger element once this is required. This way, a beverage preparation device does not require a separate water reservoir and a hot water tank.

The heat exchanger element may be an electrical heating element working at a lower end of the range for extra low voltage. The range for extra low voltage is 1-50 Volt for AC and 1-120 Volt for DC.

Preferably, the heat exchanger element has a low voltage that ranges between 10-36 V, and more preferably about 12 V DC. This way, the heat exchanger element may require less energy and can thus be connected to low energy sources, e.g. external (storage) battery. Further, the water temperature control device can, for example, be connected to a cigarette plug in a vehicle.

Due to the relatively low voltage requirement, the water temperature control device may have a hghter and more compact design and it can be portable. The heat exchanger element may, for example, be arranged to heat up 125 ml water with a temperature of 15°C to a temperature of 90°C in about 10 minutes or less.

The heat exchanger element may be a Positive Temperature Coefficient (PTC) ceramic heating element. The heat exchanger element may be made from barium titanate and lead titanate composites. The PTC ceramic heating element may have an efficiency of 60% when it is in direct contact with water and 80% when it is in contact with surfaces comprising metal. By having the heat exchanger element, e.g. PTC Ceramic heat exchanger element contacting the metal wall part, the PTC heating element may have an efficiency of 80%. For example, a heat coil inside the reservoir that would require a power of 1600 W may then be replaced by a PTC heat exchanger element, contacting the metal wall part of the reservoir, working at a power of 900 W.

The outer surface of the reservoir may be manufactured from a material having a high thermal conductivity, e.g. metal. Preferably, the reservoir is made from aluminum. Furthermore, the outer surface of the reservoir may be, at least partially, coated with thermal isolating coating, e.g. a ceramic coating to further isolate the heat within the water reservoir. As an example, the outer surface of the reservoir may be coated with Molybdenum disilicide (M0S12).

By having the outer surface of the reservoir covered with a ceramic coating, it may be achieved that the thermal energy provided by the heat exchanger element is guided via the metal outer surface to the inside of the water reservoir.

It is noted that the metal wall part, which heat exchanger element is placed against, is free from the ceramic coating. It is further noted that the outer surface parts of the reservoir that encloses the cup, is also free from ceramic coating.

Furthermore, the reservoir may be provided with a temperature sensor and/or a beverage level sensor which are connected to a controller. By having a temperature sensor the heat exchanger element may automatically shut off when a predetermined temperature of the water in the reservoir has been reached. The water level sensor may ensure that if the water level in the reservoir is too high, the heat exchanger element may remain off as a safety measure.

Furthermore, the reservoir may have a volume that, e.g. at least matches the required volume for an espresso, a cappuccino or a ristretto. However, the volume of the water reservoir may preferably be substantially larger then the volume of a single beverage to be prepared. For example, the volume of the reservoir may be at least 2, 3, 5 or even 10 times larger than the volume of a single beverage to be prepared. The volume may range in between 60- 750 ml.

The invention further relates to a use of a PTC ceramic heating element for heating water in, e.g. a water temperature control device.

The invention further relates to a beverage preparation device, in particular, a low voltage beverage preparation device for preparing, e.g. coffee, hot chocolate milk or tea. The device may have a water temperature control device, and preferably a water temperature control device as described above. Furthermore, a conduit may be provided for feeding water from the water reservoir to a brewing unit having an outlet for delivering a prepared beverage to a cup held in the cup holder.

It is noted the invention also covers a beverage preparation device that may be equipped with a regular water temperature control device, i.e. a water temperature control device without a cup holder.

The device may further comprise a pump, in particular, a rotary pump. The rotary pump may mechanically pump heated water from the water temperature control device and transfers it to the brewing unit which may comprises a tap and a pad holder for extracting, e.g. coffee. The rotary pump may be arranged below the water reservoir and connected to a reservoir outlet. Via the at least one conduit, water may be transferred from the water temperature control device through a check valve, and to the brewing unit. The tap and the pad holder may be coupled to each other with coupling means known in the art, e.g. a bayonet connection. The pad holder may be arranged above the cup holder and is arranged to receive, e.g. a coffee pad.

The rotary pump may have a voltage of 12 Volt. The pump may be arranged such that it provides for a substantially constant water flow with a substantially constant pressure of 4 bar. The rotary pump may be driven by a brushless motor. The rotary pump may have a circular rotor that is rotating inside of a larger circular cavity. The rotor may comprise vanes which are arranged to slide in and out such to seal all edges inside the cavity and creating vane chambers that do the pump work. By rotating the rotor the volume of the vane chamber at the intake side increases and decreases and the discharge side causing a relatively high pressure. An advantage of the rotary pump it that produces relatively less noise compared to pumps, e.g. vibration pumps that are used in coffee machines. Another benefit is that it can pump hot beverage under a relatively high pressure causing a more delightful cup of coffee.

It is further noted that the beverage preparation device can advantageously be a portable device and can be operated hands free. This means that the user does not need to hold onto the device when preparing the beverage. Especially when using the device in a vehicle, operating the device substantially hands free can increase the safety.

The invention further relates to a use of a low voltage rotary pump for pumping heated water in a beverage preparation device.

The invention further relates to a method of preparing beverage, comprising the steps of heating and/or cooling water in a reservoir by means of a heat exchanger element and holding a cup in a cup holder which includes a heat conducting element. Furthermore, the heat from water in the reservoir is conducted to a cup held by the cup holder or vice versa via the heat conducting element.

The invention will be further elucidated on the basis of an exemplary embodiment which is represented in a drawing. In the drawing:

Fig. 1. shows a perspective view of an embodiment of a water temperature control device according to the invention;

Fig. 2 shows a perspective view of the water temperature control device of fig. 1 with a cup held by the cup holder;

Fig. 3. shows the cross-section from the water temperature control device of fig. 1;

Fig. 4 shows a schematic overview of an embodiment of a low voltage beverage preparation device;

Fig. 5. shows a perspective view of the beverage preparation device from Fig. 4 provided with the water temperature control device of fig. i;

Fig. 6. shows the cross-section of the beverage preparation device of fig. 4;

In Fig. 1 is shown a water temperature control device 1 for use in a beverage preparation device 2. Although, the water temperature control device 1 of Fig. 1 shown is formed as a boiler that can heat water to a predetermined temperature, e.g. a temperature of at least 85°C, such as a temperature of about 90°C- 95 °C, the water temperature control device 1 may alternatively or additionally form a cooler. The water temperature control device 1 comprises a heat exchanger element 3 and a water reservoir 4 for containing water 5. The reservoir 4 in this embodiment is arranged to have a semicircle shape with a diameter that may range in between 50- 300 mm and preferably of about 90 mm at the bottom and a diameter of about 110 mm at the top, and a height that may range in between 30-400 mm and preferably of about 65 mm. However, in alternative embodiments, the volume of the reservoir 4 may for instance range in between 60-750 ml. It is noted that the reservoir may also have a cylinder shape. The reservoir 4 is arranged to contain water such that it can be used for making a beverage, e.g. coffee or tea. The reservoir 4 is provided with an opening 6 for receiving water and an outlet 7 to transport the water 5 out of the reservoir 4. Cold water may be poured into the reservoir 4 and may during the beverage preparation be heated up to a temperature of about 90°C by the heat exchanger element 3. The heat exchanger element 3 may be an external heat exchanger element, i.e. that the external heat exchanger elements, e.g. PTC elements may be attached and detached from the reservoir, in particular on or from a surface of the reservoir, e.g. the reservoir wall 17. It is noted that the opening 6 may be omitted, for example, when the water reservoir 4 is a disposable unit.

The water temperature control device 1 further includes a cup holder 8 for holding a cup 9 in which hot beverage can be poured. The cup holder 8 may have a diameter of about that may range in between 30- 100 mm and preferably about 60 mm such as 57 mm at the bottom and about 64 mm at the top, and a height that may range in between 30- 200 mm and preferably of about 40 mm such as 37 mm. The cup holder 8 may be provided with a heat conducting element 10 which, during use, heat from at least the water 5 contained in the water reservoir 4 is conducted to the cup 9 held by the cup holder 8. The cup 9 held by the cup holder 8 may contain hot beverage and this may be kept warm for a longer period of time due to the heat exchange contact of the heat conducting element 10 and the reservoir 4.

The heat conducting element 10 may be formed to extend, at least partially, along the cup 9 held by the cup holder 8. As can be seen from Fig. 2. the heat conducting element 10 encloses around the perimeter of the cup 9 held by the cup holder 8 such that the heat conducting element 10 is in close contact with the cup 9. The heat conducting element 10 comprises a thermally conductive wall part 11 of the cup holder 9 which thermally conductive wall part 11 is made from aluminum. The cup holder 8 is in this embodiment a chamber 12 for accommodating the cup. The chamber 12 encloses the cup 9 held by the cup holder 8.

In Figs. 1-3 is shown that the water reservoir 4 is arranged to contain water 5 as well as securing the cup 9 such that the cup 9 will not fall down easily. As shown, the heat conducting element 10 may be an integral part of the reservoir 4. For example, the heat conducting element 10 may comprise a reservoir wall part 14 of the reservoir 4 that surrounds the cup 9 held by the cup holder 8. The cup holder 8 is formed by a cavity in the reservoir. This way, the design of the water temperature control device 1 is lighter and more compact. In Fig. 3 is shown that the cross section of the reservoir 4 may be U-shaped. The reservoir 4 has an inner room for accommodating water 5. The inner room extends, at least partially, around a side wall, i.e. the reservoir wah part 14 of the cavity for receiving the cup. As can be seen from Fig. 3, the heat H of the water 5 will be directed towards the reservoir wall part 14. Further it shown that the cup holder 8 has a receiving area 13 for receiving the cup 9 which receiving area 13 is arranged on top of the cup holder 8.

The heat exchanger element 3 is in this embodiment arranged outside the reservoir 4. Preferably, the heat exchanger element 3 is physically contacting the outer surface 15 of the reservoir 4 for controlling and/or adjusting the temperature of the water 5 therein. For example, the heat exchanger element 3 is placed against an outside of a metal wall part of the reservoir 4 and may also be detached therefrom. The thermal energy that is emitted by the heat exchanger element 3 may be transferred to the water 5 contained in the reservoir 4 via a reservoir wall 17. To increase the heat exchange surface, the heat exchanger element 3 may be, at least partially, enclosing the outer surface 15 of the reservoir 4.

The heat exchanger element 3 is in this example embodied as an electrical heating element working at a lower end of the range for extra low voltage. The electrical heating element requires a voltage of 12 Volt DC. Preferably, the heat exchanger element 3 is a PTC (Positive Temperature Coefficient) ceramic heating element. PTC ceramic heating elements are known for having a positive thermal coefficient of resistance, i.e. the resistance increases upon heating. Consequently, when the heat exchanger element 3 is cold more current may pass through the heating element, and when the heating element is warm, less current may pass through. By using PTC ceramic heating elements there is no additional temperature regulation or safety device necessary while reaching the required heat-power level.

Furthermore, the reservoir 4, in particular, the reservoir wall 17, may comprise metal, e.g. aluminum to improve the heat exchange contact between the heat conducting element 10 and the reservoir 4. Further, the outer surface 15 of the reservoir 4 may be, at least partially, coated with a thermal isolating coating, e.g. a ceramic coating to isolate thermal energy from, e.g. the heat exchanger element 3, or the reservoir 4, escaping to the surroundings. The reservoir wall 17 may be partially covered by the ceramic coating. The reservoir wall part 14 of the reservoir 4 is free from the ceramic coating since it is in heat exchange contact with the cup 9 held by the cup holder 8. The cup 9 is then in heat exchange contact with the reservoir wall part 14 of the reservoir 4 that comprises metal.

The reservoir 4 may be provided with a temperature sensor 18 and/or a fluid level sensor 19 which are connected to a controller (not shown). These sensors determine whether the temperature of the beverage 5 contained in the reservoir 4 is within the predetermined limit, and if the reservoir 4 is not too full.

In Figs 4-6, a beverage preparation device 2 is shown which is portable and operates at a low voltage that may ranges in between 6-36 Volt. The device 2 may be used by connecting it to a cigarette plug of a car vehicle. The device 2 comprises a water temperature control device 1, a rotary pump 20 and a tap 21. The tap 21 may be coupled to a pad holder 21. In Fig. 4 a schematic overview is shown of the low voltage beverage preparation device 2. Water may be pored into a reservoir 4 and being heated by a PTC ceramic heating element 3 that is preferably arranged outside the reservoir 4. The rotary pump 20 may then mechanically pump heated water 5 out of the reservoir 4 in the direction of the tap 21. Between the tap 21 and the rotary pump 20, a check valve 23 may be arranged to prevent waterflowback. The tap 21 may be coupled to a pad holder 21 which holds, e.g. a pad of coffee (not shown). The tap 21 is connected to the pad holder 21 via a bayonet coupling. The tap 21 may have, e.g. six outlet channels through which the heated water may exit towards the pad holder 21. The distance between the tap 21 and the pad holder 21 may be about 1.5 mm which in combination with the pump pressure gives a mechanically pressure of about 14 bar. This high pressure results in a cup of coffee with a natural crème layer. The pad holder 22 and/or the tap 21 may be arranged above the cup 9 held in a cup holder 8 of the water temperature control device 1.

The rotary pump 20 may comprise ceramic composite components to withstand the high temperature and pressurized water. The pump 20 may have a voltage of 12 Volt DC and may be driven by a brushless motor (not shown).

As for the purpose of this disclosure, it is pointed out that technical features which have been described may be susceptible of functional generalization. It is further pointed out that - insofar as not explicitly mentioned- such technical features can be considered separately from the context of the given exemplary embodiment, and can further be considered separately from the technical features with which they cooperate in the context of the example.

It is pointed out that the invention is not limited to the exemplary embodiment represented here, and that many variants are possible. For example, the low voltage beverage preparation device may be equipped with a regular water heating device, i.e. a water temperature control device without a cup holder. Also, it is possible that the water temperature control device as described herein uses preheated beverage and the heat exchanger element controls the temperature of the preheated beverage in the reservoir. Such variants will be clear to the skilled person, and are considered to be within the scope of the invention as defined in the appended claims.

LIST OF REFERENCE NUMERALS 1. Water temperature control device 2. Beverage preparation device 3. Heat exchanger element 4. Reservoir 5. Water 6. Water opening 7. Water outlet 8. Cup holder 9. Cup 10. Heat conducting element 11. Wall part of the heat conducting element 12. Compartment 13. Cup holder receiving area 14. Reservoir wall part 15. Outer surface of the reservoir 16. Side surface of the reservoir 17. Reservoir wall 18. Temperature sensor 19. fluid level sensor 20. rotary pump 21. tap 22. pad holder 23. check valve

Claims

A water temperature control device for use in a beverage preparation device, the water temperature control device comprising: a water reservoir for containing water for beverage preparation; a heat exchanger element for heating and / or cooling water in the water reservoir; and a cup holder for holding a cup, the cup holder comprising a heat-conducting element for conducting heat from water in the water reservoir to the cup held by the cup holder or vice versa.

The water temperature control device according to claim 1, wherein the heat-conducting element is formed to extend, at least partially, along a cup held by the cup holder.

The water temperature control device according to claim 1 or 2, wherein the thermally conductive element is formed to extend, at least in part, around a side wall of a cup held by the cup holder.

The water temperature control device according to any one of the preceding claims, wherein the heat-conducting element comprises a thermally conductive wall part of the cup holder.

The water temperature control device according to any one of the preceding claims, wherein the cup holder defines a chamber for accommodating a cup.

The water temperature control device according to any one of the preceding claims, wherein the water reservoir is provided with a cavity for receiving a cup, said cavity forming the cup holder.

The water temperature control device according to claim 6, wherein the water reservoir defines an inner chamber for accommodating the water, and wherein said inner chamber extends, at least in part, around a side wall of the cavity for receiving a cup.

The water temperature control device according to any one of the preceding claims, wherein the water reservoir comprises a metal wall part, the heat exchanger element being placed against an outside of said metal wall part.

The water temperature control device according to any of the preceding claims, wherein the heat exchanger element comprises an electric heat element that operates in the lower end of the extra low voltage range.

The water temperature control device according to any of the preceding claims, wherein the heat exchanger element comprises a PTC ceramic heat element.

A beverage preparation device, in particular a low voltage beverage preparation device, comprising: a water temperature control device according to any one of the preceding claims; and a line for feeding water from the water reservoir to a brewing unit provided with an outlet for supplying a prepared beverage to a cup held in the cup holder.

The device of claim 11, further comprising a pump, in particular a rotary pump, for pumping the water through the conduit.

The device of claim 11 or 12, wherein the brewing unit comprises a pod holder.

A method for preparing a beverage, comprising the steps of: heating and / or cooling water in a water reservoir by means of a heat exchanger element; holding a cup in a cup holder comprising a heat-conducting element for transferring heat between the water reservoir and the cup; and conducting heat from water in the reservoir to a cup held by the cup holder, or vice versa, via the heat-conducting element.