Pumping two-phase cooling system

Abstract

The invention relates to a pumping two-phase cooling system comprising a two-phase working fluid circuit having: a first circuit section (2) for conducting a first portion of the working fluid to a preheater assembly (4, 4 ', 4' '), the first portion in the first circuit section (2) having a first thermal characteristic; a second circuit section (6) for guiding a second portion of the working fluid to the preheater assembly (4), the second portion in the second circuit section (6) having a second thermal characteristic; and a third circuit section (8) for guiding a third portion of the working fluid from the preheater assembly (4) to the at least one evaporator (10), the third portion in the third circuit section (8) having a third thermal characteristic based on the first thermal characteristic and the second thermal characteristic.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a pumped two-phase cooling system. BACKGROUND

[0002] Pumped two-phase cooling systems utilize the latent heat of vaporization of a working fluid to remove thermal energy from a component to be cooled.

[0003] Fig. 1 schematically illustrates a known pumped two-phase cooling system. The system comprises a working fluid circuit 200 for guiding a two-phase working fluid.

[0004] The system further comprises a pump 300 for pumping the working fluid through the circuit 200. The system further comprises a preheater 400, an evaporator 500, a condenser 600, and a reservoir 100, also sometimes referred to as a collector. The circuit 200 connects these devices 400, 500, 600, 100 to allow the working fluid to flow through the evaporator 500 and subsequently through the condenser 600. The pump 300 sequentially pumps the working fluid through the preheater 400, the evaporator 500, and the condenser 600.

[0005] The evaporator 500 is configured to cool a thermal energy dissipating component, e.g. a power electronics device. To this end, the evaporator 500 is arranged and designed to absorb heat from the respective component to be cooled.

[0006] The preheater 400 increases the temperature of the working fluid entering the preheater 400 in liquid phase to its saturation temperature, i.e. to its optimum working point. Thus, the working fluid enters the evaporator 500 at least substantially at its saturation temperature. Thus, the heat or thermal energy absorbed by the working fluid flowing through the evaporator 500 causes the working fluid to partially evaporate. Thus, the working fluid leaving the evaporator 500 is partially in liquid phase and partially in gaseous phase.

[0007] Subsequently, the working fluid is guided by the circuit 200 to the condenser 600, in which heat is removed from the working fluid to restore it to the liquid phase. The condenser 600 dissipates the heat to the surrounding environment.

[0008] The reservoir 100 is configured to balance the system. To this end, the reservoir 100 stores excess working fluid and compensates for volume changes.

[0009] By using the latent heat of the working fluid, it is possible to achieve, under otherwise identical conditions, that a two-phase cooling system requires less pumping power in principle than a single-phase cooling system.

[0010] However, the preheater 400 still requires a certain amount of electrical energy to generate the respective heat. This results in a limited efficiency and a limited reliability of the system.

[0011] Therefore, there is a need for an improved two-phase cooling system, in particular for a two-phase cooling system having improved features in terms of efficiency and reliability. SUMMARY

[0012] According to the present disclosure, a pumped two-phase cooling system is provided, comprising a two-phase working fluid circuit. The circuit has a first circuit section for guiding a first portion of the working fluid to a preheater assembly. The first portion in the first circuit section has a first thermal characteristic. The circuit further has a second circuit section for guiding a second portion of the working fluid to the preheater assembly. The second portion in the second circuit section has a second thermal characteristic. The circuit further comprises a third circuit section for guiding a third portion of the working fluid from the preheater assembly to at least one evaporator. The third portion in the third circuit section has a third thermal characteristic based on the first thermal characteristic and the second thermal characteristic.

[0013] By providing the second circuit section, additional thermal energy can be supplied to the working fluid in the first circuit section, i.e. before it enters the evaporator. In this way, the need for a preheater requiring external energy can be eliminated or at least the system can be operated using a preheater assembly requiring less energy compared to the preheater of the cooling system according to the prior art described above. In other words, the preheater assembly of the cooling system according to the present specification can not require or at least require less external energy compared to the prior art.

[0014] Therefore, in principle, less energy is required to operate the cooling system. As a result, the two-phase cooling system can show an improved efficiency, which leads to an improved reliability.

[0015] Various embodiments can implement the following features:

[0016] The preheater assembly can be configured to heat the working fluid to its saturation temperature or at least close to its saturation temperature. This is generally advantageous in terms of the cooling capacity of the system. In particular, the preheater assembly can be configured to heat the working fluid in such a way that its temperature is at or close to its saturation temperature when it enters the evaporator.

[0017] The term "temperature close to the saturation temperature" is intended to describe a temperature within a certain temperature interval including the saturation temperature. The temperature interval can be 6 K or 5 K or 4 K or 3 K or 2 K.

[0018] The preheater assembly can comprise an electrical heating device for heating the working fluid. For example, in this way, the time between starting the system and reaching an optimal temperature of the working fluid upstream of the evaporator can be kept particularly short.

[0019] The circuit can further comprise a fourth circuit section for guiding a fourth portion of the working fluid from the at least one evaporator to the condenser. The second circuit section can be connected to the fourth circuit section. Upon leaving the evaporator, i.e. in the fourth circuit section, the working fluid has a relatively large amount of thermal energy. Thus, by providing a connection between the fourth circuit section and the second circuit section, this thermal energy can particularly advantageously be used to feed the preheater assembly.

[0020] Thus, the preheater assembly can use thermal energy that is already in the system. The second circuit section can be used to tap some of the thermal energy of the working fluid in the fourth circuit section and feed it back to the preheater assembly, particularly in a controlled manner, where it mixes with a “main stream” in the form of a flow of the first portion of the working fluid in the first circuit section to heat it.

[0021] The circuit can further comprise a fifth circuit section for guiding a fifth portion of the working fluid from the condenser to the first circuit section, wherein the first portion of the working fluid is derived from the fifth portion. In this way, a closed circuit or closed loop for guiding the working fluid is provided.

[0022] The fifth circuit section can comprise a reservoir for the working fluid. The reservoir can be configured to balance the system, e.g. by storing excess working fluid and compensating for volume changes of the working fluid.

[0023] The system can further comprise a pump for pumping the working fluid through the two-phase working fluid circuit. The pump can be provided in, e.g., the fifth circuit section, e.g. between the reservoir and the first circuit section.

[0024] The thermal properties can comprise temperature and / or pressure and / or thermal energy. The first thermal property can comprise the working fluid being in a liquid phase, the second thermal property can comprise the working fluid being partly in a liquid phase and partly in a gaseous phase, and the third thermal property can comprise the working fluid being in a liquid state. The first thermal property can be different from the third thermal property. In particular, the third thermal property can comprise the working fluid comprising more energy than the first thermal property.

[0025] The system can further comprise a valve arranged within the second circuit section. The valve can influence the flow strength (i.e. the volume flow rate) of the working fluid through the second circuit section. In this way, it can influence how much thermal energy is supplied to the preheater assembly by the working fluid flowing through the second circuit section. The valve can be a one-way valve.

[0026] The valve can be configured to allow the working fluid to flow from the fourth circuit section to the preheater assembly via the second circuit section, and further configured to prevent the working fluid from flowing from the preheater assembly to the fourth circuit section via the second circuit section. In particular, this at least substantially prevents thermal energy from being extracted from the working fluid in the first circuit section before the working fluid subsequently enters the evaporator.

[0027] The valve can be configured to control the flow of working fluid from the fourth circuit section to the preheater assembly via the second circuit section. In this way, the thermal energy fed to the first portion of working fluid, i.e. the working fluid in the first circuit section, can be quantitatively determined.

[0028] The system can further comprise at least one temperature and / or pressure sensor device for measuring the temperature and / or pressure of the working fluid. The at least one temperature and / or pressure sensor device can be arranged within the first circuit section and / or the third circuit section. A temperature or pressure sensor can also or alternatively be provided in the second circuit section. The temperature or pressure values measured by the temperature and / or pressure sensor device can particularly advantageously be used for improving the control of the flow of working fluid through the second circuit section.

[0029] To this end, for example, the valve can be configured to operate using temperature and / or pressure information generated or measured by the temperature and / or pressure sensor device.

[0030] The preheater assembly can comprise a junction configured to allow the first portion of working fluid to mix with the second portion of working fluid. In this way, a configuration can be achieved which is simple in structure and therefore particularly reliable for mixing the first portion of working fluid with the second portion of working fluid.

[0031] The preheater assembly can further comprise a coupling circuit section connecting the junction to the third circuit section. The coupling circuit section can be, for example, tubular.

[0032] The electrical heating device of the preheater assembly, if provided, can be arranged in the coupling circuit section.

[0033] The preheater assembly can further comprise a heat exchanger connected to the first circuit section and to the second circuit section, the heat exchanger being configured to exchange heat between the first portion of working fluid and the second portion of working fluid. The heat exchanger allows to improve the control of the heat exchange between the working fluid originating from the first circuit section and the working fluid originating from the second circuit section. The heat exchanger can be configured to exchange heat between the first portion of working fluid and the second portion of working fluid without exchanging working fluid.

[0034] In particular, the configuration can be such that the working fluid condenses in the heat exchanger and transfers its thermal energy to the "main stream" in the form of a flow of the first portion of working fluid in the first circuit section. Subsequently, the working fluid mixes with the "main stream" downstream of the heat exchanger.

[0035] The system can further comprise an extension circuit section for guiding the working fluid originating from the second circuit section to the coupling circuit section connecting the first circuit section to the third circuit section after passing through the heat exchanger.

[0036] The system can also include an auxiliary pump for pumping working fluid from the extension circuit segment to the third circuit segment. Depending on the system design and pressure levels, an auxiliary pump is required. However, the auxiliary pump requires less energy compared to a preheater according to the prior art as described above.

[0037] The preheater assembly can also include a heat exchanger connected to the second circuit segment and a coupling circuit segment connecting the first circuit segment to the third circuit segment. The heat exchanger can be configured to exchange heat between working fluid originating from the second circuit segment and working fluid within the coupling circuit segment.

[0038] Here, the working fluid mixes with the "main flow" upstream of the heat exchanger.

[0039] The system can also include an extension circuit segment for directing working fluid originating from the second circuit segment to the coupling circuit segment at a point between the first circuit segment and the heat exchanger after passing through the heat exchanger. The point can be between the first circuit segment and the pump, or between the pump and the preheater assembly.

[0040] Alternatively, the extension circuit segment can be configured to direct working fluid originating from the second circuit segment to a reservoir after passing through the heat exchanger.

[0041] The system can also include an auxiliary pump for pumping working fluid from the extension circuit segment to the coupling circuit segment or the reservoir.

[0042] According to alternative or additional aspects of the invention, there is provided a pumped two-phase cooling system comprising a reservoir containing a two-phase working fluid, an evaporator, a condenser, a two-phase working fluid circuit connecting the reservoir, the evaporator, and the condenser, the two-phase working fluid circuit being configured to allow working fluid to flow through the evaporator and the condenser. The system further comprises a pump configured to pump working fluid through the circuit, and a preheater assembly arranged and configured to preheat working fluid before it enters the evaporator. The circuit comprises a first circuit portion configured to allow working fluid to flow from the evaporator to the condenser, a second circuit portion configured to allow working fluid to flow from the condenser to the evaporator, and a third circuit portion connecting the first circuit portion to the second circuit portion bypassing the condenser.

[0043] In particular, the present disclosure comprises the following aspects:

[0044] 1. A pumped two-phase cooling system comprising:

[0045] a two-phase working fluid circuit having

[0046] a first circuit segment for directing a first portion of working fluid to a preheater assembly, the first portion in the first circuit segment having a first thermal characteristic,

[0047] a second circuit section for directing a second portion of the working fluid to the preheater assembly, the second portion in the second circuit section having a second thermal characteristic, and

[0048] a third circuit section for directing a third portion of the working fluid from the preheater assembly to the at least one evaporator, the third portion in the third circuit section having a third thermal characteristic based on the first and second thermal characteristics.

[0049] 2. The pumped two-phase cooling system of aspect 1, the preheater assembly being configured to heat the working fluid to its saturation temperature or at least close to its saturation temperature.

[0050] 3. The pumped two-phase cooling system of aspect 2, the preheater assembly comprising an electrical heating device for heating the working fluid.

[0051] 4. The pumped two-phase cooling system of any preceding aspect, the two-phase working fluid circuit further comprising a fourth circuit section for directing a fourth portion of the working fluid from the at least one evaporator to a condenser, the second circuit section being connected to the fourth circuit section.

[0052] 5. The pumped two-phase cooling system of aspect 4, the two-phase working fluid circuit further comprising a fifth circuit section for directing a fifth portion of the working fluid from the condenser to the first circuit section, wherein the first portion of the working fluid is derived from the fifth portion.

[0053] 6. The pumped two-phase cooling system of aspect 5, the fifth circuit section comprising a reservoir for the working fluid.

[0054] 7. The pumped two-phase cooling system of any preceding aspect, further comprising a pump for pumping the working fluid through the two-phase working fluid circuit.

[0055] 8. The pumped two-phase cooling system of any preceding aspect, the first thermal characteristic comprising the working fluid being in a liquid phase, the second thermal characteristic comprising the working fluid portion being in a liquid phase and partly in a gaseous phase, and the third thermal characteristic comprising the working fluid being in a liquid phase.

[0056] 9. The pumped two-phase cooling system of any preceding aspect, further comprising a valve arranged within the second circuit section.

[0057] 10. The pumped two-phase cooling system of aspect 9, including the features of aspect 4, the valve being configured to allow the working fluid to flow from the fourth loop segment to the preheater assembly via the second loop segment, and further configured to prevent the working fluid from flowing from the preheater assembly to the fourth loop segment via the second loop segment.

[0058] 11. The pumped two-phase cooling system of aspect 9 or 10, the valve being configured to control the flow of the working fluid from the fourth loop segment to the preheater assembly via the second loop segment.

[0059] 12. The pumped two-phase cooling system of any preceding aspect, further comprising at least one temperature and / or pressure sensor device for measuring a temperature and / or pressure of the working fluid, the at least one temperature and / or pressure sensor device being disposed within the first loop segment and / or the third loop segment.

[0060] 13. The pumped two-phase cooling system of any preceding aspect, including the features of aspects 9 and 12, wherein the valve is configured to operate using temperature and / or pressure information generated by the temperature and / or pressure sensor device.

[0061] 14. The pumped two-phase cooling system of any preceding aspect, the preheater assembly comprising a junction configured to allow the first portion of the working fluid to mix with the second portion of the working fluid.

[0062] 15. The pumped two-phase cooling system of aspect 14, the preheater assembly further comprising a coupling loop segment connecting the junction to the third loop segment.

[0063] 16. The pumped two-phase cooling system of aspect 15, including the features of aspect 3, the electric heating device being disposed in the coupling loop segment.

[0064] 17. The pumped two-phase cooling system of any of aspects 1 to 13, the preheater assembly further comprising a heat exchanger connected to the first loop segment and the second loop segment and configured to exchange heat between the first portion of the working fluid and the second portion of the working fluid.

[0065] 18. The pumped two-phase cooling system of aspect 17, further comprising an extension loop segment for directing working fluid originating from the second loop segment after passing through the heat exchanger to a coupling loop segment connecting the first loop segment to the third loop segment.

[0066] 19. The pumped two-phase cooling system of aspect 18, further comprising an auxiliary pump for pumping the working fluid from the extension loop segment to the third loop segment.

[0067] 20. The pumped two-phase cooling system of any of aspects 1 to 13, the preheater assembly further comprising a heat exchanger connected to the second loop segment and a coupling loop segment connecting the first loop segment to the third loop segment, the heat exchanger configured to exchange heat between working fluid originating from the second loop segment and working fluid within the coupling loop segment.

[0068] 21. The pumped two-phase cooling system of aspect 20, further comprising an extension loop segment for directing working fluid originating from the second loop segment to the coupling loop segment at a point between the first loop segment and the heat exchanger after passing through the heat exchanger.

[0069] 22. The pumped two-phase cooling system of aspect 21, further comprising an auxiliary pump for pumping the working fluid from the extension loop segment to the coupling loop segment.

[0070] 23. The pumped two-phase cooling system of aspect 20, further comprising an extension loop segment for directing working fluid originating from the second loop segment to the reservoir after passing through the heat exchanger.

[0071] 24. The pumped two-phase cooling system of aspect 23, further comprising an auxiliary pump for pumping the working fluid from the extension loop segment to the reservoir.

[0072] 25. A pumped two-phase cooling system, preferably according to any of the preceding aspects, comprising a reservoir containing a two-phase working fluid,

[0073] an evaporator,

[0074] a condenser,

[0075] a two-phase working fluid loop connecting the reservoir, the evaporator, and the condenser, and configured to allow the working fluid to flow through the evaporator and the condenser,

[0076] a pump configured to pump the working fluid through the loop,

[0077] a preheater assembly arranged and configured to preheat the working fluid before entering the evaporator,

[0078] the loop comprising

[0079] a first loop portion configured to allow the working fluid to flow from the evaporator to the condenser,

[0080] a second circuit portion configured to allow the working fluid to flow from the condenser to the evaporator, and

[0081] a third circuit portion connecting the first circuit portion to the second circuit portion bypassing the condenser.

[0082] 26. The pumped two-phase cooling system of aspect 25, the pump being configured to sequentially pump the working fluid through the condenser and the reservoir.

[0083] 27. The pumped two-phase cooling system of any one of aspects 25 to 26, the pump being configured to sequentially pump the working fluid through the preheater and the evaporator.

[0084] 28. The pumped two-phase cooling system of any one of aspects 25 to 27, the third circuit portion constituting a return line for allowing the working fluid to return from the first circuit portion to the second circuit portion upstream of the evaporator.

[0085] 29. The pumped two-phase cooling system of any one of aspects 25 to 28, the third circuit portion being connected to the second circuit portion at a connection to allow a portion of the working fluid to flow from the third circuit portion into the second circuit portion at the connection.

[0086] 30. The pumped two-phase cooling system of aspect 29, further comprising a mixing arrangement disposed at the connection and configured to control a mixing ratio between a flow of working fluid from the third circuit portion into the second circuit portion and another flow of working fluid from a first portion of the second circuit portion upstream of the connection into a second portion of the second circuit portion downstream of the connection.

[0087] 31. The pumped two-phase cooling system of any one of aspects 25 to 30, the third circuit portion being connected to the second circuit portion at the preheater assembly.

[0088] 32. The pumped two-phase cooling system of any one of aspects 25 to 31, further comprising a valve disposed within the third circuit portion.

[0089] 33. The pumped two-phase cooling system of aspect 32, the valve being configured to allow the working fluid to flow from the first circuit portion to the second circuit portion via the third circuit portion, and further configured to prevent the working fluid from flowing from the first circuit portion to the first circuit portion via the third circuit portion.

[0090] 34. The pumped two-phase cooling system of any of aspects 25-33, further comprising at least one temperature and / or pressure sensor device disposed within the second circuit portion or the third circuit portion and configured to measure a temperature or pressure of the working fluid.

[0091] 35. The pumped two-phase cooling system of aspect 34, the at least one temperature and / or pressure sensor device disposed between the pump and the preheater assembly or between the preheater assembly and the evaporator.

[0092] 36. The pumped two-phase cooling system of aspect 35, comprising at least two temperature and / or pressure sensor devices, a first of the at least two pressure and temperature sensor devices disposed between the pump and the preheater assembly and a second of the at least two pressure and temperature sensor devices disposed between the preheater assembly and the evaporator.

[0093] 37. The pumped two-phase cooling system of any of aspects 25-36, further comprising a heat exchanger disposed and configured to exchange heat between at least a portion of the working fluid within the third circuit portion and at least another portion of the working fluid within the second circuit portion.

[0094] 38. The pumped two-phase cooling system of aspect 37, the heat exchanger disposed proximate to or within the preheater assembly.

[0095] 39. The pumped two-phase cooling system of aspect 37 or 38, further comprising another pump configured to pump the working fluid from the third circuit portion to the second circuit portion.

[0096] 40. The pumped two-phase cooling system of aspect 39, the another pump disposed at the third circuit portion between the heat exchanger and a second portion of the second circuit portion.

[0097] 41. The pumped two-phase cooling system of any of aspects 37-40, the third circuit portion connected to the second circuit portion between the heat exchanger and the evaporator.

[0098] 42. The pumped two-phase cooling system of any of aspects 37-40, the third circuit portion connected to the second circuit portion between the reservoir and the pump or between the pump and the heat exchanger.

[0099] 43. The pumped two-phase cooling system of any of aspects 25-42, the third circuit portion connected to the second circuit portion between the condenser and the reservoir. BRIEF DESCRIPTION OF DRAWINGS

[0100] The subject matter of the present disclosure will be explained in greater detail in view of the preferred exemplary embodiments shown in the figures.

[0101] Fig. 1 is a schematic diagram of a pumped two-phase cooling system according to the prior art.

[0102] Figure 2 is a schematic diagram of a pumped two-phase cooling system according to a first embodiment.

[0103] Figure 3 is a schematic diagram of a pumped two-phase cooling system according to a second embodiment.

[0104] Figure 4 is a schematic diagram of a pumped two-phase cooling system according to a third embodiment. DETAILED DESCRIPTION

[0105] Figure 2 is a schematic diagram of a pumped two-phase cooling system according to a first embodiment. The cooling system comprises a two-phase working fluid circuit for guiding a two-phase working fluid.

[0106] The system further comprises a pump 20, a preheater assembly 4, an evaporator 10, and a condenser 14. The pump 20 is configured to pump the working fluid through the circuit. In particular, the system is configured such that the working fluid can be pumped by the pump 20 through the evaporator 10 and the condenser 14 via the circuit.

[0107] Figure 2 The shown system shows an example system with only one evaporator 10. However, the system can comprise multiple evaporators. For example, the evaporators can be connected in series or in parallel.

[0108] Further, the system comprises an accumulator 18 for balancing the system.

[0109] The circuit comprises a first circuit section 2, a second circuit section 6, and a third circuit section 8. The first circuit section 2 is configured to direct a first portion of the working fluid to the preheater assembly 4. The second circuit section 6 is configured to direct a second portion of the working fluid to the preheater assembly 4. The third circuit section 8 is configured to direct a third portion of the working fluid from the preheater assembly 4 to the evaporator 10.

[0110] The first portion of the working fluid has a first thermal characteristic, including the working fluid being in a liquid phase. The second portion of the working fluid has a second thermal characteristic, including the working fluid portion being in a liquid phase and a portion being in a gaseous phase. The third portion of the working fluid has a third thermal characteristic, including the working fluid being in a liquid phase.

[0111] The third thermal characteristic is based on the first thermal characteristic and the second thermal characteristic.

[0112] The preheater assembly 4 comprises a junction 22 configured to allow the first portion of working fluid to mix with the second portion of working fluid. In other words, the working fluid originating from the first circuit segment 2 and the working fluid originating from the second circuit segment 6 mix at the junction 22 within the preheater assembly 4. Thus, the thermal energy of the working fluid leaving the preheater assembly 4, i.e. the third portion of working fluid, is based on or depends on the first thermal property and the second thermal property. The third thermal property also depends on the first volumetric flow rate of the first portion of working fluid to reach the junction 22 and the second volumetric flow rate of the second portion of working fluid to reach the junction 22.

[0113] The preheater assembly 4 further comprises a coupling circuit segment 24 connecting the junction 22 to the third circuit segment 8, such that working fluid can flow from the junction 22 into the third circuit segment 8 via the coupling circuit segment 24.

[0114] The preheater assembly 4 is configured to heat the working fluid to its saturation temperature or at least close to its saturation temperature.

[0115] The circuit further comprises a fourth circuit segment 12 for guiding a fourth portion of working fluid from the evaporator 10 to the condenser 14. In other words, the fourth circuit segment 12 connects the evaporator 10 with the condenser 14, such that working fluid can flow from the evaporator 10 to the condenser 14.

[0116] The second circuit segment 6 is connected to the fourth circuit segment 12. In other words, one end of the second circuit segment 6 enters the preheater assembly 4 and the other, opposite end of the second circuit segment 6 is in fluid connection with the fourth circuit segment 12.

[0117] The circuit further comprises a fifth circuit segment 16 for guiding a fifth portion of working fluid from the condenser 14 to the first circuit segment 2. In other words, the fifth circuit segment 16 connects the condenser 14 with the first circuit segment 2, such that working fluid can flow from the condenser 14 to the first circuit segment 2.

[0118] The reservoir 18 and / or the pump 20 can be provided within the fifth circuit segment 16, as Figure 2 illustrated.

[0119] The preheater assembly 4 can comprise an electric heating device for heating the working fluid. The heating device can be provided and arranged to heat the working fluid within the coupling circuit segment 24, i.e. between the junction 22 and the evaporator 10. This way, the electric heating device can heat the working fluid to its saturation temperature or at least close to its saturation temperature, if the working fluid downstream of the junction 22 has not yet reached the desired temperature for entering the evaporator 10. This can be particularly advantageous in an initial phase after start-up of the system, as long as the average temperature of the working fluid has not yet reached an equilibrium level.

[0120] The system can further comprise a valve 26 arranged within the second circuit section 6. The valve 26 can be configured to allow a flow of working fluid from the fourth circuit section 12 to the preheater assembly 4 via the second circuit section 6. The valve 26 can be configured to prevent a flow of working fluid from the preheater assembly 4 to the fourth circuit section 12 via the second circuit section 6.

[0121] The valve 26 can further be configured to control the flow, i.e. the volume flow rate, of working fluid from the fourth circuit section 12 to the preheater assembly 4 via the second circuit section 6. In this way, the thermal energy fed by the working fluid within the second circuit section 6 to the preheater assembly 4 can be adjusted.

[0122] The system can further comprise at least one temperature and / or pressure sensor device 30, 32 for measuring a temperature and / or a pressure of the working fluid. The at least one temperature and / or pressure sensor device 30, 32 can be arranged within, for example, the first circuit section 2 and / or the third circuit section 8. The temperature or pressure measured by the temperature and / or pressure sensor device 30, 32 can advantageously be used to improve the control of the thermal properties of the working fluid.

[0123] In particular, the valve 26 can be configured to operate using temperature and / or pressure information generated by the temperature and / or pressure sensor device 30, 32.

[0124] Figure 3 is a schematic diagram of a pumped two-phase cooling system according to a second embodiment.

[0125] The above description of the first embodiment applies mutatis mutandis to the other embodiments, unless stated otherwise below. Reference symbols are used in an analogous manner.

[0126] The preheater assembly 4’ according to the second embodiment comprises a heat exchanger 34 connected to the first circuit section 2 and the second circuit section 6. The preheater assembly 34 is configured to exchange heat between the first portion of working fluid and the second portion of working fluid. The system further comprises an extension circuit section 36 for guiding the working fluid originating from the second circuit section 6 after passing through the heat exchanger 34 to a coupling circuit section 38, which couples the first circuit section 2 to the third circuit section 8.

[0127] Furthermore, the system comprises an auxiliary pump 40 for pumping working fluid from the extension circuit section 36 to the third circuit section 8.

[0128] The auxiliary pump 40 can be configured to operate only when needed. Due to the arrangement of the second circuit section 6 and the extension circuit section 36, it can be considered that the auxiliary pump 40 in principle requires less energy than the corresponding pump according to the prior art described above.

[0129] Figure 4 is a schematic diagram of a pumped two-phase cooling system according to a third embodiment.

[0130] The preheater assembly 4” according to the third embodiment comprises a heat exchanger 42 connected to the second circuit section 6 and to a coupling circuit section 44 connecting the first circuit section 2 to the third circuit section 8. The heat exchanger 42 is configured to exchange heat between the working fluid originating from the second circuit section 6 and the working fluid within the coupling circuit section 44.

[0131] The system further comprises an extension circuit section 46 for directing the working fluid originating from the second circuit section 6 to the coupling circuit section 44 at a point 48 between the first circuit section 2 and the heat exchanger 42 after passing through the heat exchanger 42. The point 48 can for example be between the first circuit section 2 and the pump 2 or between the pump 20 and the heat exchanger 42. Alternatively, the extension circuit section can be configured to direct the working fluid originating from the second circuit section 6 to the reservoir 18 after passing through the heat exchanger 42.

[0132] The system further comprises an auxiliary pump 50 for pumping the working fluid from the extension circuit section 46 to the coupling circuit section 44 or to the reservoir 18. The auxiliary pump 50 can be configured to operate only when needed. Due to the arrangement of the second circuit section 6 and the extension circuit section 46, the auxiliary pump 40 can be considered to in principle require less energy than the corresponding pump according to the prior art described above.

[0133] While the present disclosure has been described in detail in the foregoing drawings and description, such description is to be considered illustrative or exemplary and not restrictive; the disclosure is not limited to the embodiments described herein. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. The word "comprising" does not exclude other elements not listed, the indefinite article "a" or "an" does not exclude a plurality, and the mere fact that measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. A pumped two-phase cooling system comprising: Two-phase working fluid circuit with a first circuit section (2) for directing a first portion of the working fluid to a preheater assembly (4, 4', 4"), the first portion in the first circuit section (2) having a first thermal characteristic, a second circuit section (6) for directing a second portion of the working fluid to the preheater assembly (4), the second portion in the second circuit section (6) having a second thermal characteristic, and A third circuit segment (8) for directing a third portion of the working fluid from the preheater assembly (4) to at least one evaporator (10), the third portion in the third circuit segment (8) having a third thermal characteristic based on the first thermal characteristic and the second thermal characteristic.

2. The pumped two-phase cooling system according to claim 1, wherein the two-phase working fluid circuit further comprises a fourth circuit section (12) for directing a fourth portion of the working fluid from the at least one evaporator (10) to a condenser (14), the second circuit section (6) being connected to the fourth circuit section (12).

3. The pumped two-phase cooling system according to claim 2, wherein the two-phase working fluid circuit further comprises a fifth circuit segment (16) for directing a fifth portion of the working fluid from the condenser (14) to the first circuit segment (2), wherein The first portion of the working fluid originates from the fifth portion.

4. The pumped two-phase cooling system according to claim 3, the fifth circuit section (16) comprising a reservoir (18) for the working fluid.

5. A pumped two-phase cooling system according to any one of the preceding claims, further comprising a pump (20) for pumping the working fluid through the two-phase working fluid circuit.

6. A pumped two-phase cooling system according to any one of the preceding claims, further comprising a valve (26), preferably a non-return valve, arranged in the second circuit section (6).

7. The pumped two-phase cooling system according to claim 6, comprising the features of claim 2, wherein the valve (26) is configured to allow the working fluid to flow from the fourth circuit segment (12) via the second circuit segment (6) to the preheater assembly (4), and the valve (26) is also configured to prevent the working fluid from flowing from the preheater assembly (4, 4', 4") via the second circuit segment (6) to the fourth circuit segment (12).

8. The pumped two-phase cooling system according to claim 6 or 7, the valve (26) being configured to control the flow of the working fluid from the fourth circuit section (12) via the second circuit section (6) to the preheater assembly (4, 4', 4").

9. The pumped two-phase cooling system according to any of the preceding claims, further comprising at least one temperature and / or pressure sensor device (30, 32) for measuring the temperature and / or pressure of the working fluid, wherein the at least one pressure and / or temperature sensor device (30, 32) is arranged in the first circuit section (2) and / or in the third circuit section (8).

10. A pumped two-phase cooling system according to any one of the preceding claims, including the features of claims 6 and 9, wherein: The valve (26) is configured to operate using temperature and / or pressure information generated by the temperature and / or pressure sensor arrangement (30, 32).

11. The pumped two-phase cooling system of any one of the preceding claims, the preheater assembly (4) comprising a joint (22) configured to allow mixing of the first portion of the working fluid with the second portion of the working fluid.

12. The pumped two-phase cooling system according to any one of claims 1 to 10, the preheater assembly (4') further comprising a heat exchanger (34) connected to the first circuit section (2) and the second circuit section (6), and the heat exchanger being configured to exchange heat between the first portion of the working fluid and the second portion of the working fluid, The system further comprises an extended circuit section (36) for guiding the working fluid originating from the second circuit section (6) after passing through the heat exchanger (34) to a connecting circuit section (38) connecting the first circuit section (2) to the third circuit section (8).

13. The pumped two-phase cooling system according to claim 12, further comprising an auxiliary pump (40) for pumping the working fluid from the extended circuit section (36) to the third circuit section (8).

14. The pumped two-phase cooling system according to any one of claims 1 to 10, the preheater assembly (4") further comprising a heat exchanger (42) connected to the second circuit section (6) and a coupling circuit section (44), the coupling circuit section connecting the first circuit section (2) to the third circuit section (8), the heat exchanger (42) being configured to exchange heat between the working fluid originating from the second circuit section (6) and the working fluid in the coupling circuit section (44), The system also includes an extended circuit section (46) for directing the working fluid originating from the second circuit section (6) to the coupling circuit section (44) at a point (48) between the first circuit section (2) and the heat exchanger (42) after the working fluid has passed through the heat exchanger (42).

15. The pumped two-phase cooling system of claim 14, further comprising an auxiliary pump (50) for pumping the working fluid from the extended circuit section (46) to the coupled circuit section (44).

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