System for preparing a coffee-based beverage

Abstract

The present invention relates to a system (100) for preparing a coffee-based beverage, which system allows to selectively dispense a high-temperature beverage or a beverage with reduced temperature. The system according to the invention comprises a brewing group (10) for preparing a coffee-based beverage, a cooling device (40) in which the coffee-based beverage that exits from the brewing group releases heat to a cooling fluid, and a valve assembly (70) for making the beverage exiting from the brewing group selectively flow through the cooling device (30) or not. Advantageously, said valve assembly is arranged downstream of the cooling device (30), so that said valve assembly is not subjected to unnecessary thermal stress.

Description

[0001] “System for preparing a coffee-based beverage"

[0002] Technical Field

[0003] The present invention relates to a system for preparing a coffee-based beverage.

[0004] More particularly, the present invention relates to a system for preparing a coffee-based beverage comprising a brewing group and means for reducing the temperature of the coffee-based beverage exiting from the brewing group.

[0005] Background Art

[0006] Systems for preparing coffee-based beverages are known, allowing obtaining alternatively beverages at a high temperature or beverages at a reduced temperature. More particularly, said systems generally comprise a brewing group in which the coffee-based beverage is obtained by making a stream of water at a high-temperature (about 85 - 95 °C) pass through a coffee powder panel, the coffee-based beverage correspondingly exiting at a high temperature from said brewing group.

[0007] The beverage thus obtained can be dispensed directly at the temperature at which it exits the brewing group, or its temperature can be reduced prior to dispensing.

[0008] Depending on the needs, such temperature reduction can be more or less intense. According to some solutions, the beverage can be cooled down to temperatures lower than or equal to ambient temperature and be dispensed and served at said temperatures. According to other solutions, the beverage can be cooled down to a less extent, in the order of a few tenths of degrees. In this case, the beverage can be served accompanied by ice cubes, and the initial temperature reduction immediately downstream of brewing has the purpose of preventing a sudden melting of the ice and allowing, instead, a slow and gradual melting of the ice cubes.

[0009] Several solutions are known for obtaining the desired cooling of the coffee-based beverage.

[0010] For example, some known solutions envisage to temporarily store the coffee-based beverage in a refrigerating apparatus, in order to reduce the temperature of said beverage.

[0011] While, on one part, such solutions allow adjusting the final temperature of the beverage by acting on the dwell time of the beverage in the refrigerating apparatus, on the other part they do not allow serving a freshly brewed beverage, i.e., a beverage prepared at the time the user orders it. Other known solutions envisage mixing the beverage obtained in the brewing group with cold water, ice or other coolants.

[0012] In this case, too, the final temperature of the beverage can be adjusted by varying the amount of coolant added thereto. However, the addition of a non-negligible amount of water or ice can negatively affect the organoleptic qualities of the resulting beverage. In addition, as mentioned above, the direct addition of ice to the hot beverage and the resulting quick melting of ice therein should be avoided.

[0013] Further known solutions envisage using cooling devices employing, for example, cooling members of the type of Peltier cells, or cooling circuits equipped with a compressor, a condenser and an evaporator.

[0014] Such solutions share a high degree of complexity of the means used for cooling down the beverage, which results in high production costs and an increased need for maintenance.

[0015] Finally, solutions are known in which the beverage exiting the brewing group exchanges heat with a stream of water (for example, water coming from the water mains) in a heat exchanger.

[0016] These solutions, besides being simple, have the advantage that - if the water used in the heat exchanger is then used for brewing a beverage dispensed afterwards - the heat released by the hot beverage can be exploited to obtain a pre-heating of water before it enters the boiler.

[0017] Document EP 3 125 730 describes a method for preparing a coffee-based beverage at low temperature, said method providing for a step of brewing a dose of coffee powder by means of a high-temperature water flow and a subsequent step of cooling down the thus obtained beverage by means of thermal contact with a flow of cold water.

[0018] The aforementioned document also discloses, correspondingly, a coffee machine comprising a brewing group for preparing a coffee-based beverage at high temperature and at least one heat exchanger arranged downstream of the brewing group and comprising a primary side in which said coffee-based beverage flows, and a secondary side in which low-temperature water flows.

[0019] Said coffee machine comprises a switchover valve arranged between the brewing group and the heat exchanger, so that the user can select dispensing of a low-temperature beverage or dispensing a high-temperature beverage, and the flow of high-temperature beverage exiting the brewing group is selectively sent to the heat exchanger or to a bypass pipe and from there directly to a dispensing spout.

[0020] Document EP 2268 175 similarly discloses a method for preparing a cold, coffee-based beverage that is prepared from a hot beverage, obtained by brewing a dose of coffee powder. In order to obtain a beverage with good organoleptic qualities, the cold beverage is produced continuously immediately after preparation of the hot beverage, without storage in refrigerated devices or direct addition of coolants.

[0021] Correspondingly, the aforesaid document also discloses a coffee machine comprising a brewing group for preparing a high-temperature, coffee-based beverage and a cooling device that is arranged downstream of the brewing group and includes a primary side in which said coffee-based beverage flows, and a secondary side in which a cooling liquid flows.

[0022] For quick, selective switching of the coffee machine from dispensing hot beverages to dispensing cold beverages and vice versa, a system can be provided at the outlet of the brewing group in order to selectively connect said brewing group directly to a dispensing spout for hot beverages of the coffee machine, or, alternatively, to the inlet of the cooling device.

[0023] The known solutions therefore allow selectively obtaining a high-temperature, coffeebased beverage or, alternatively, a coffee-based beverage with reduced temperature, depending on user selection.

[0024] However, they are not without drawbacks.

[0025] In particular, all the components of the coffee machine are arranged upstream of the cooling device.

[0026] Therefore, even when the user selects a low-temperature beverage, all the components downstream of the brewing group come into contact with the coffee-based beverage when this is at a high temperature.

[0027] This causes significant thermal stress to these components and reduces their useful life. The object of the present invention is therefore to overcome the above-mentioned drawback by providing a system for preparing coffee-based beverages that allows avoiding subjecting the system components to unnecessary thermal stress.

[0028] These and other features are achieved with the system for preparing a coffee-based beverage as claimed in the appended claims.

[0029] Summary of Invention

[0030] The system according to the invention comprises a brewing group for preparing a coffee-based beverage with high temperature and a cooling device arranged downstream of said brewing group.

[0031] According to the invention, the system further comprises a set of ducts comprising at least a duct exiting from the brewing group and branching into a duct leading to the cooling device and a bypass duct without the interposition of any switching valve; said set of ducts further comprises a duct that exits from the cooling device and merges into the bypass duct with the interposition of a valve assembly comprising at least one switching valve; said set of ducts finally comprises a dispensing duct arranged downstream of said valve assembly for connection to a dispensing spout.

[0032] Thanks to the structure of the system according to the invention, and in particular to the particular positioning of the valve assembly, said valve assembly comes into contact with a high-temperature beverage flow only if the user has selected the dispensing of a hot coffee-based beverage. Instead, if the user selects the dispensing of a cold coffeebased beverage, the valve assembly comes into contact with the beverage flow after the temperature thereof has already been reduced inside the cooling device.

[0033] Therefore, the thermal stresses to which the valve assembly is subjected are reduced compared to known solutions, and the useful life of the valve assembly is correspondingly increased.

[0034] In a preferred embodiment of the invention, the valve assembly comprises at least a first switching valve that selectively puts the dispensing duct into communication with the bypass duct or with the duct exiting from the cooling device, and a second switching valve that is arranged downstream of the first switching valve and selectively puts the valve assembly into communication with the dispensing duct or with a drainage duct ending in a drain.

[0035] In a first embodiment of the invention, the cooling device comprises a single heat exchanger comprising a primary side in which the coffee-based beverage exiting from the brewing group flows, and a secondary side in which a cooling liquid flows, whereby the high-temperature coffee-based beverage that exits from the brewing group releases heat to the flow of cooling fluid.

[0036] In this embodiment, the cooling fluid preferably is water coming from a cold water source (e.g., the water mains).

[0037] In this way, the device for cooling the coffee-based beverage also serves as a device for pre-heating water, which can then by fed to a boiler for actual heating, and from there to the brewing group of the system according to the invention.

[0038] In a second embodiment of the invention, the cooling device comprises a first heat exchanger comprising a primary side, in which the coffee-based beverage exiting from said brewing group flows, and a secondary side, which is part of a closed-loop circuit, in which a first cooling fluid flows, whereby the high-temperature coffee-based beverage exiting from the brewing group releases heat to the flow of the first cooling fluid.

[0039] The circuit of the first cooling fluid is provided with a pump for circulating the first cooling fluid.

[0040] In a particularly advantageous variant of this second embodiment of the invention, the power of said pump can be varied, thus varying the flow rate of the first cooling fluid in the first cooling fluid circuit: by adjusting the flow rate of the first cooling fluid it is possible to continuously adjust the temperature of the coffee-based beverage at the outlet of the heat exchanger and, thus, the temperature at which said beverage is dispensed.

[0041] In this second embodiment of the invention, the cooling device further comprises a second heat exchanger, in which the first cooling fluid circulating in the circuit for the Said second cooling fluid is preferably water coming from a cold water source (e.g., the water mains).

[0042] In this way, the device for cooling the coffee-based beverage also, advantageously, serves as a device for pre-heating water, which can then be supplied to a boiler for actual heating, and from there to the brewing group of the system according to the invention.

[0043] Compared to the first embodiment in which heat is released directly from the brewed beverage to the water, the system according to this second embodiment of the invention maintains the advantageous possibility of pre-heating the water used in the brewing group, but it is more flexible thanks to the interposition of the first cooling fluid circuit, which makes it possible to introduce a certain number of degrees of freedom (nature of the cooling fluid, flow rate of the cooling fluid, etc.).

[0044] Brief Description of Drawings

[0045] Further features and advantages of the present invention will become more evident from the following detailed description of some preferred embodiments, given by way of non-limiting examples with reference to the annexed drawings, in which: Fig.1 schematically shows the hydraulic system according to a first embodiment of the invention;

[0046] Fig.2 schematically shows the hydraulic circuit of the system according to a second embodiment of the invention.

[0047] Description of Embodiments

[0048] Figure 1 schematically illustrates the essential components of the hydraulic circuit of a system for the preparation of coffee-based beverages according to a first preferred embodiment of the invention.

[0049] Said system can be implemented, for example, in espresso coffee machines, and particularly (though not exclusively) in espresso coffee machines of the fully automatic type.

[0050] It will be apparent to the person skilled in the art that such coffee machines may comprise in a manner known per se the desired components necessary to prepare coffeebased beverages (coffee powder storage tanks, or coffee bean storage tanks and related grinder-dosers, milk tanks, milk frothing / whipping means and so on).

[0051] Such components are not described herein because they are known per se and not strictly necessary to the understanding of the invention.

[0052] Referring to Figure 1, the hydraulic circuit of a system for preparing coffee-based beverages 100 comprises, among others, a brewing group 10, in which a coffee-based beverage is prepared by making a stream of water at a high temperature (about 85 -95°C) pass through a coffee powder panel.

[0053] For this purpose, the system 100 comprises a water circuit 20 supplied with cold water coming from a water source 22. Said water source 22 can be either the water mains or a dedicated tank.

[0054] A pump 24 and a boiler 26 are arranged along the water circuit 20, upstream of the brewing group 10.

[0055] The boiler 26 makes it possible to increase the water temperature from the initial temperature at the water source 22 (for example, the temperature of the water mains, or the ambient temperature) to the temperature desired for brewing the coffee panel in the brewing group 10.

[0056] The pump 24 makes it possible to promote the circulation of water from the cold water source 22 to the boiler 26 and from the latter to the brewing group 10. In addition, the pump 24 can be used for increasing the water pressure so that the stream of water passing through the coffee panel in the brewing group 10 has not only a high temperature, but also a high pressure.

[0057] In order to be able to obtain, if the user so wishes, a low temperature beverage, the system 100 comprises, downstream of the brewing group 10, a cooling device 30 capable of reducing the temperature of the coffee-based beverage exiting from said brewing group 10.

[0058] In the shown embodiment, said cooling device 30 comprises a single heat exchanger 32, in which there are provided a primary side 32a, in which the coffee-based beverage exiting from the brewing group 10 flows, and a secondary side 32b, in which a cooling fluid flows.

[0059] As visible in Figure 1, advantageously, the secondary side 32b of the heat exchanger 32 is formed by a section of the water circuit 20 arranged upstream of the boiler 26, so that the water flowing in said secondary side 32b of said heat exchanger 32, by absorbing heat from the coffee-based beverage, is pre-heated before entering said boiler 26, this resulting in energy savings.

[0060] To allow the system 100 to dispense both high-temperature beverages and beverages with reduced temperature (depending on the user’s selection), the hydraulic circuit of the system 100 comprises, downstream of the brewing group 10, a set of ducts 40 (beverage circuit 40) comprising at least:

[0061] - a duct exiting from the brewing group 42, which duct is arranged at the outlet of said brewing group 10;

[0062] - a duct leading to the cooling device 44, which duct connects the duct exiting from the brewing group 42 to the inlet of the heat exchanger 32;

[0063] - a duct exiting from the cooling device 46, which duct is arranged at the outlet of the heat exchanger 32;

[0064] - a duct bypassing the cooling device 48, said bypass duct allowing to bypass the heat exchanger 32;

[0065] - a dispensing duct 50, which ends with a dispensing spout 60 for dispensing the coffee-based beverage;

[0066] wherein said duct exiting from the brewing group 42 branches into said duct leading to the cooling device 44 and said bypass duct 48, without the interposition of any switching valve, wherein said bypass duct merges into said duct exiting from the cooling device 46 with the interposition of a valve assembly 70 comprising at least a first switching valve 72, and wherein said dispensing duct 50 is arranged between said valve assembly 70 and said dispensing spout 60.

[0067] The first switching valve 72 allows selectively communicating the dispensing duct 50 either with the bypass duct 48 (in the event that the system 100 has to dispense a high-temperature coffee-based beverage) or with the duct exiting from the cooling device 46 (in the event that the system 100 has to dispense a coffee-based beverage with a limited temperature).

[0068] Preferably, the set of ducts 40 further comprises a drainage duct 52 arranged between the valve assembly 70 and a drain 80, and the valve assembly correspondingly comprises a second switching valve 74, arranged downstream of the first switching valve and suitable for putting the valve assembly 70 into communication either with the di spending duct 50 or with the drainage duct.

[0069] It will be apparent to the person skilled in the art that in the system 100 according to the invention, the valve assembly 70 comes into contact with a flow of high-temperature fluid only if a hot beverage is to be dispensed; instead, whenever the user selects a cold beverage, said valve assembly comes into contact with a flow of fluid with reduced temperature, thus avoiding unnecessary thermal stress.

[0070] As visible in Figure 1, the water circuit 20 of the hydraulic circuit of the system 100 is equipped with a bypass circuit bypassing the cooling device 28 as well as with corresponding valves appropriately arranged and structured so as to allow, if desired, to prevent water coming from the water mains 22 from passing through heat exchanger 32.

[0071] In addition, the hydraulic circuit of the system 100 comprises a duct bypassing the brewing group 90, said bypass duct being arranged between a point downstream of the boiler 26 and the inlet of the brewing group 10 and the duct exiting from the brewing group 42, as well as with corresponding valves appropriately arranged and structured so as to allow, if desired, to prevent water coming from the boiler 26 from passing through the brewing group 10 and the coffee powder dose.

[0072] The duct bypassing the brewing group 90 allows high-temperature water to flow into the set of ducts 40.

[0073] This possibility can be useful, in particular, for the purpose of rinsing the ducts of the set of ducts 40 at the end of the dispensing of a coffee-based beverage and before the next dispensing. The operation of the system for preparing coffee-based beverages 100 according to the invention can be summarized as follows.

[0074] At the end of the step of rinsing the set of ducts 40, both the duct leading to the cooling device 42 and the bypass duct 48 are full of water.

[0075] If the user selects the dispensing of a hot beverage, cold water is taken from the water mains 22, supplied to the boiler 26 and from there to the brewing group 10.

[0076] The first switching valve 72 of the valve assembly 70 is arranged so as to connect the bypass duct 48 with the dispensing duct 50, and the second switching valve 74 is arranged so as to put the valve assembly 70 into communication with the drain 80. The coffee-based beverage that exits from the brewing group 10 pushes the water contained in the set of ducts 40, and in particular (thanks to the first switching valve) the water present in the bypass duct 48, towards the drain 80.

[0077] At the end of the duct exiting from the brewing group 42, the coffee-based thus flows into the bypass 48 (also in the absence of any switching valve arranged upstream of the cooling device).

[0078] When the coffee-based beverage has advanced to the valve assembly 70, the second switching valve 74 is switched so as to put said valve assembly into communication with the dispensing duct 50 and the dispensing spout 60, so that the high-temperature coffee-based beverage is dispensed.

[0079] If the user selects the dispensing of a cold beverage, cold water is still taken from the water mains 22, supplied to the boiler 26 and from there to the brewing group 10. In this case, however, the first switching valve 72 of the valve assembly 70 is arranged so as to connect the duct exiting from the cooling device 46 with the dispensing duct 50, and the second switching valve 74 is arranged so as to put said valve assembly 70 into communication with the drain 80.

[0080] The coffee-based beverage exiting from the brewing group 10 pushes the water contained in the set of ducts 40, and in particular (thanks to the first switching valve) the water present in the duct leading to the cooling device 44 and in the duct exiting from the cooling device 46, towards the drain 80.

[0081] At the end of the duct exiting from the brewing group 42, the coffee-based beverage thus flows into the duct leading to the cooling device 44 (also in the absence of any switching valve arranged upstream of the cooling device) and through the heat exchanger 32, thereby releasing heat to the water. When the coffee-based beverage has advanced to the valve assembly 70, the second switching valve 74 is switched so as put said valve assembly into communication with the dispensing duct 50 and the dispensing spout 60, whereby the coffee-based beverage with reduced temperature is dispensed.

[0082] Turning now to Figure 2, this shows a second embodiment of the invention, which differs from the previous embodiment in the structure of the cooling device, the other parts of the hydraulic system 100 being identical or substantially identical to those of the first embodiment (to which reference is made for a detail description thereof). In this second embodiment of the invention, the cooling device 30 comprises a first heat exchanger 34, arranged downstream of the brewing group 10 and provided with a primary side 34a, in which the coffee-based beverage exiting from the brewing group 10 flows, and a secondary side 34b, which is formed by a corresponding section of a first cooling fluid circuit 36 in which a first cooling fluid circulates.

[0083] The first cooling fluid circuit 36 is a closed-loop circuit.

[0084] In this case, the first cooling fluid can be other than water and can be, for example, Glysofor F (a propylene glycol-based coolant widely used in the food industry) or an aqueous solution of Glysofor F.

[0085] In the first heat exchanger 34, the coffee-based beverage flowing in the primary side 34a releases heat to the first cooling fluid circulating in the secondary side 34b and in this way it is cooled down.

[0086] In a particularly advantageous variant of embodiment, a variable power pump 36a is arranged in the first cooling fluid circuit 36. In this way, by controlling the power of the pump 36a it is possible to control the flow rate of the first cooling fluid in the first cooling fluid circuit 36, and in particular in the secondary side 34b of the first heat exchanger 34.

[0087] As a result, by varying the flow rate of the first cooling fluid in the first heat exchanger 34 it is possible to continuously control the temperature of the beverage exiting from said first heat exchanger 34 and then exiting from the dispensing duct.

[0088] The cooling device further comprises a second heat exchanger 38 arranged along the first cooling fluid circuit 36, so that a corresponding section of the cooling fluid circuit 36 forms a primary side 38a of said heat exchanger.

[0089] A second cooling fluid circulates in the secondary side 38b of the second heat exchanger 38, so that the first cooling fluid which flows in the primary side 38a (and has absorbed heat from the coffee-based beverage in the first heat exchanger 34) releases heat to the flow of second cooling fluid which circulates in the secondary side 38b and is thus cooled down.

[0090] As visible in Figure 2, the second cooling fluid is water and the secondary side 38b of the second heat exchanger 38 is formed by a corresponding section of the water circuit 20.

[0091] In this way, advantageously, the water circulating in the secondary side 38b, by absorbing heat from the first cooling fluid, is pre-heated before entering the boiler 26. Thanks to the possibility of selecting a cooling fluid other than water and (if provided for) controlling the flow rate of said cooling fluid inside the first heat exchanger 34, the system according to this second embodiment of the invention has higher flexibility than the one according to the previously described first embodiment, which higher flexibility justifies the greater complexity of said second embodiment.

[0092] The operation of the system 100 according to this second embodiment, especially as far as the possibility of selectively dispensing a high-temperature coffee-based beverage or a coffee-based beverage with reduced temperature is concerned, is completely analogous to that of the first embodiment of the invention and will therefore not be reported here in detail.

[0093] It will be apparent that the embodiments described herein have been provided purely by way of example and not by way of limitation, and numerous modifications and variations within the reach of a person skilled in the art - in particular with respect to the structure and operation of the cooling device - are possible without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS1. System (100) for preparing a coffee-based beverage comprising:- a brewing group (10), for preparing said coffee-based beverage by brewing a dose of coffee powder;- a water circuit (20), for bringing water at a high temperature to said brewing group (io);- a cooling device (30), arranged downstream of the brewing group (10) and suitable for reducing the temperature of the coffee-based beverage exiting from said brewing group (10);- a set of ducts (40), arranged downstream of said brewing group (10) and comprising at least:- a duct exiting from the brewing group (42), which duct is arranged at the outlet of said brewing group;- a duct leading to the cooling device (44), which duct connects said duct exiting from the brewing group (42) to the inlet of said cooling device (30);- a duct exiting from the cooling device (46), which duct is arranged at the outlet of said cooling device (30);- a bypass duct (48) allowing to bypass said cooling device (30);- a dispensing duct (50), which ends with a dispensing spout (60) for dispensing the coffee-based beverage;wherein said duct exiting from the brewing group (42) branches into said duct leading to the cooling device (44) and said bypass duct (48), wherein said bypass duct (48) merges into said duct exiting from the cooling device (46), and wherein said dispending duct (50) is arranged downstream of the point of merger between said bypass duct (48) and said duct exiting from the cooling device (46),characterized in that said duct exiting from the brewing group (42) branches into said duct leading to the cooling device (44) and said bypass duct (48) without the interposition of any switching valve, and in that said bypass duct (48) merges into said duct exiting from the cooling device (46) with the interposition of a valve assembly (70) comprising at least a first switching valve (72), said first switching valve (72) allowing said dispensing duct to be selectively put into communication (50) either with said bypass duct (48) or with said duct exiting from the cooling device (46).

2. System (100) according to claim 1, wherein said set of ducts (40) further comprisesa drainage duct (52) arranged between said valve assembly (70) and a drain (80), and wherein said valve assembly (70) comprises a second switching valve (74), arranged downstream of said first switching valve (72) and suitable for putting said valve assembly (70) into communication either with said dispensing duct (50) or with said drainage duct (52).

3. System (100) according to claim 1 or 2, further comprising a duct bypassing the brewing group (90) and arranged between a point of said water circuit upstream of said brewing group (10) and said duct exiting from the brewing group (42), and valves suitable for allowing the water flowing in said water circuit to selectively pass either through said brewing group (10) or through said duct bypassing the brewing group (90).

4. System (100) according to claim 1 or 2 or 3, wherein said water circuit (20) is supplied with cold water coming from a water source (22), and wherein a pump (24), suitable for promoting the circulation of water from said water source to said brewing group and, possibly, for increasing the pressure of the water circulating in said water circuit, and a boiler (26), suitable for raising the temperature of the water coming from said water source (22), are arranged along said water circuit (20), upstream of said brewing group (10).

5. System (100) according to any of claims 1 - 4, wherein said cooling device (30) comprises a single heat exchanger (32) in which there are provided a primary side (32a), which is connected to said duct leading to the cooling device (44) and in which the coffee-based beverage exiting from said brewing group (10) flows, and a secondary side (32b) in which a cooling fluid flows.

6. System (100) according to claim 5, wherein said cooling fluid is water, and wherein said secondary side (32b) of said heat exchanger (32) is formed by a section of said water circuit (20).

7. System (100) according to claims 4 and 6, wherein said secondary side (32b) of said heat exchanger (32) is formed by a section of said water circuit (20) arranged upstream of said boiler (26).

8. System (100) according to any of claims 1 - 4, wherein said cooling device (30) comprises a first heat exchanger (34), provided with a primary side (34a), which is connected to said duct leading to the cooling device (44) and in which the coffee-based beverage exiting from said brewing group (10) flows, and a secondary side (34b), formed by a section of a closed-loop cooling fluid circuit (36), in which a first coolingfluid flows.

9. System (100) according to claim 8, wherein a variable power pump (36a) is provided in said cooling fluid circuit (36).

10. System (100) according to claim 8 or 9, wherein said cooling device (30) comprises a second heat exchanger (38) arranged along said cooling fluid circuit (36), wherein a section of said cooling fluid circuit (36) forms a primary side (38a) of said second heat exchanger, and wherein said second heat exchanger comprises a secondary side (38b) in which a second cooling fluid flows.

11. System (100) according to claim 10, wherein said second cooling fluid is water and wherein said secondary side (38b) of said second heat exchanger (38) is formed by a section of said water circuit (20).

12. System (100) according to claims 4 and 11, wherein said secondary side (38b) of said second heat exchanger (32) is formed by a section of said water circuit (20) arranged upstream of said boiler (26).

13. System (100) according to any of claims 8 - 12, wherein said first cooling fluid is Glysofor F or an aqueous solution of Glysofor F.

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