EP2828589A1

EP2828589A1 - Refrigeration system

Info

Publication number: EP2828589A1
Application number: EP13711051.6A
Authority: EP
Inventors: Birte MARGOTTI; Stephan Rölke
Original assignee: Bitzer Kuehlmaschinenbau GmbH and Co KG
Current assignee: Bitzer Kuehlmaschinenbau GmbH and Co KG
Priority date: 2012-03-21
Filing date: 2013-03-21
Publication date: 2015-01-28
Anticipated expiration: 2033-03-21
Also published as: US20130247603A1; RU2014142091A; WO2013139909A1; EP2828589B1; DE102012102404A1; CN103322739A; RU2615864C2; US9194619B2; CN103322739B

Abstract

In order to improve a refrigeration system, comprising a refrigeration cycle in which a refrigerant compressor, a condenser following the refrigerant compressor, an expansion device following the condenser and an evaporator following the expansion device are arranged, said evaporator being connected in return with the refrigerant compressor, wherein the refrigerant compressor has a variable speed drive motor controlled by an electronic motor control unit and a control cooling branch through which refrigerant flows and which branches off from the refrigerant cycle between the condenser and the expansion device and which is guided to a connection of the refrigerant compressor and in which a heat sink that is thermally conductively connected to electronic power components of the motor control unit is arranged, in such a manner that malfunctions in the motor control unit are avoided to the greatest possible extent, a regulating system for the control cooling branch is provided which, during operation of the refrigerant compressor, regulates a temperature of the heat sink such that a minimum evaporation temperature of the heat sink lies above a freezing point temperature and below a condensation temperature of the refrigerant in the condenser.

Description

- -

COOLING SYSTEM

The invention relates to a refrigeration system comprising a refrigeration cycle in which a refrigerant compressor, a condenser following the refrigerant compressor, an expansion device following the condenser and an evaporator following the expansion device are arranged, which in turn is connected to the refrigerant compressor, wherein the refrigerant compressor by a an electronic engine control speed-controlled drive motor has, and a refrigerant flow through Steuerungskühlungszweig which branches off from the refrigeration circuit between the condenser and the expansion device and is guided to a connection of the refrigerant compressor and in which a heat-conductively connected to electronic power components of the engine control heat sink is arranged.

Such refrigeration systems are known.

In these, however, there is the problem that the cooling of the heat sink in the control cooling branch leads to problems in the electric motor control, either because the electronic power components of the engine control are too hot or too much cooling of the heat sink occurs, leading to icing or condensation in the Area of the heat sink can cause, which in turn causes malfunction in the engine control.

The invention is therefore based on the object to improve a refrigeration system of the generic type such that malfunctions of the engine control are avoided as possible. - -

This object is achieved in a refrigeration system of the type described above according to the invention that a control for the control cooling branch is provided which controls a temperature of the heat sink during operation of the refrigerant compressor so that a Mindestverdampfungs- temperature of the heat sink above a freezing point and below a Condensing temperature of the refrigerant in the condenser is.

The advantage of this solution is the fact that it can be ensured by setting the minimum evaporation temperature, which is above a freezing point temperature of water, that the heat sink does not freeze.

It is even better if the minimum evaporation temperature of the heat sink is above a dew point temperature of the surroundings of the engine control.

With this solution it can be ensured that a condensation of water can be prevented on the heat sink, which can also lead to disturbances of the engine control, in particular a damage of the same.

A particularly favorable solution provides that the temperature of the heat sink is at least at a settable by an evaporation pressure of the refrigerant in the heat sink minimum evaporation temperature or higher.

By adjusting the evaporation pressure, it can be ensured that in no case does the temperature of the heat sink fall below the minimum evaporation temperature corresponding to the evaporation pressure.

To ensure that a reliable temperature control of the heat sink is also during a start-up phase of the refrigerant compressor, is It is preferably provided that in a start-up phase of the refrigerant compressor, a minimal refrigerant flow flows through the heat sink.

The minimum flow of refrigerant through the heat sink ensures that a cooling capacity control for the heat sink is functional even in the start-up phase and starts as soon as possible after switching on the refrigerant compressor.

It is particularly advantageous if the control in the start-up phase allows a minimal flow of refrigerant through the control cooling branch, so that the entire control cooling branch is traversed by the minimum flow of refrigerant and thus, the temperature control provided for this in the cooling body receives the control activity.

With regard to the setting of the evaporation pressure in the heat sink, the most diverse solutions are conceivable.

So a particularly favorable solution provides that the attitude of the

Evaporating pressure in the heat sink by a evaporation pressure regulator takes place.

A particularly favorable solution provides that the control has an evaporation pressure regulator, which regulates an evaporation pressure in the cooling element so that it lies above a pressure at the connection of the refrigerant compressor to which the control cooling branch is connected.

Such a vapor pressure regulator can be a mechanical

Be evaporation pressure regulator. - -

However, it is also conceivable that the evaporation pressure regulator is an electrically or electronically operating evaporation pressure regulator which, for example, controls a control valve with pulse-width modulation in order to regulate the evaporation pressure.

It is particularly advantageous if the evaporation pressure regulator allows for the minimum refrigerant flow when switching on the refrigerant compressor in the start-up phase, that is, that the evaporation pressure regulator operates so that this allows in any case, the minimum refrigerant flow regardless of the intended control.

In this case, it can be accepted, for example, that the evaporation pressure regulator is ineffective or limited in effect during the startup of the refrigerant compressor in the start-up phase.

Evaporative pressure control is of minor importance when starting up the refrigerant compressor in the start-up phase, as opposed to the minimum refrigerant flow required to assure power control of the heat sink.

Such a control inefficiency of the evaporation pressure regulator can be achieved, for example, in a mechanical evaporation pressure regulator or an electrically or electronically controlled evaporation pressure regulator, that the evaporation pressure regulator is assigned a bypass line with a throttle, wherein the throttle defines the minimum refrigerant flow, so that regardless of whether the evaporation pressure regulator works or not, the minimum refrigerant flow is ensured by the control cooling branch.

Another advantageous solution provides that the evaporation pressure regulator comprises a control valve and a pressure control and that the pressure control in the start-up phase of the refrigerant compressor, the control valve so - - controls that it allows the minimum flow of refrigerant primarily before the evaporation pressure control.

In connection with the previous explanation of the individual embodiments was no longer discussed how a temperature control of the heat sink can be done.

A particularly favorable solution provides that the connection of the refrigerant compressor for the control cooling branch is not the connection of the refrigerant compressor, which is connected to the evaporator, but a connection of the refrigerant compressor, on a relative to the associated with the evaporator port higher pressure, for example an intermediate pressure of the refrigerant compressor is located.

For example, in the case of forming the refrigerant compressor, provided as a screw compressor, the connection of the refrigerant compressor, which is connected to the control cooling branch, leads into a closed compressor chamber of the screw compressor.

Such a solution has the great advantage that it gives the possibility of not affecting the intake volume of the refrigerant compressor due to the refrigerant flow guided through the control cooling branch.

Furthermore, this solution has the advantage that it already by the

Connection of the refrigerant compressor is a pressure level is specified, which ensures a pressure level and thus a temperature in the heat sink, which is above the lowest possible temperature of the evaporator, even with no existing control function of the evaporating pressure regulator.

For example, an electronic temperature control with a controlled control valve would be conceivable. - -

An electronic temperature control with a controlled control valve, however, has disadvantages in terms of cost and reliability.

For this reason, a particularly advantageous solution provides that the control cooling branch comprises a thermostatic expansion valve upstream of the heat sink, which is controlled by a temperature sensor on the heat sink.

The temperature sensor could be provided centrally or in the course of a cooling channel in the heat sink.

However, the temperature sensor is expediently arranged at an output connection of the heat sink.

In order to ensure even when providing a thermostatic expansion valve that flows in the start-up phase of the refrigerant compressor, a minimal flow of refrigerant through the heat sink, it is preferably provided that the expansion valve is associated with a bypass line with a throttle.

Such a bypass line for the expansion valve makes it possible to flow a minimal refrigerant flow through the heat sink even with the expansion valve closed in the start-up phase and thus, for example, build up an evaporation pressure, which causes the evaporation pressure regulator comes into action and thus also the minimum flow of refrigerant in the start-up phase, regardless of whether the expansion valve already regulates or not.

This minimum refrigerant flow through the heat sink ensures that when the heat sink heats up, the expansion valve can react quickly to prevent overheating of the heat sink and thus overheating of the electronic power components. - -

Further features and advantages of the invention are the subject of the following description and the drawings of some embodiments.

In the drawing show:

Fig. 1 is a schematic representation of a refrigerant compressor;

Fig. 2 is a schematic representation of a motor control of

Refrigerant compressor with coupled in this cooling element;

3 is a schematic representation of a first embodiment of a refrigeration system according to the invention;

4 is a schematic representation of a second embodiment of a refrigeration system according to the invention;

5 is a schematic representation of a third embodiment of a refrigeration system according to the invention;

Fig. 6 is a schematic representation of a fourth embodiment of a refrigeration system according to the invention and

Fig. 7 is a schematic representation of a fifth embodiment of a refrigeration system according to the invention.

An embodiment of a refrigerant compressor 10 used in the invention is designed as a screw compressor, as described for example in German patent applications DE 198 45 991 AI or DE 103 59 032 AI. - -

Such a screw compressor includes, for example, a first

Screw rotor 12 and a second screw rotor 14, which are each rotatably disposed in screw rotor bores 16 and 18 of a screw compressor housing 20 and engage with their peripheral screw contours 22 and 24, wherein the screw contours 22 and 24 in the region of a suction side arranged inlet window 26 at least partially open compression chambers form and subsequent to the inlet window 26 closed and increasingly reduced volume compressor chambers form, which in turn in the region of an outlet window 28, the pressure side of the screw rotors 16 and 18 is arranged, open in this.

Thus, there is a suction pressure PS at the inlet window 26 and an outlet pressure PA at the outlet window 28 which is above the suction pressure PS.

In a screw compressor, however, it is also possible to supply refrigerant at an intermediate pressure PZ into the compression chambers closed by the screw contours 22 and 24 after the inlet window 26, for example at an intermediate pressure level PZ1 which forms in the closed compression chambers forming after the inlet window 26 or at an intermediate pressure level PZ2 present in the compression chambers near the outlet window 28.

In order to be able to supply refrigerant to the screw compressor at the different pressure levels, it is provided with an inlet connection AE, to which refrigerant with the suction pressure is supplied, with an intermediate pressure connection AZ1, to which intermediate pressure refrigerant PZ1 can be supplied, with an intermediate pressure connection AZ2, to which refrigerant with the intermediate pressure PZ2 can be supplied, and with an output port AA, at which refrigerant at the outlet pressure PA exits. - -

To drive the screw rotors 12 and 14, one of the screw rotors can be driven by a drive motor 30, which can be controlled by a motor controller 32 in a speed-controlled manner, wherein the motor controller 32, as shown in FIG. 2, an electronic speed control 34 comprises, for example, an inverter which has highly temperature-stressed electronic power components 36, which have a high heat development during operation of the drive motor 30 with the motor control 32, and too large

Heating during operation of the drive motor 30 show a shortened life.

For this reason, it is necessary to thermally couple the electronic power components 36 to a heat sink 40, where they can give off their heat.

In order to prevent overheating of these electronic power components 36, the heat sink 40 is provided with an input port 42 and an outlet port 44 for a refrigerant and between the

The inlet port 42 and the outlet port 44 extends in the heat sink 40, a cooling channel 46 which can be flowed through in the cooling body 40 in such a way that the cooling body 40 can be cooled substantially uniformly with the coolant; in particular, the cooling channel 46 runs such that a optimum heat dissipation of the thermally coupled to the heat sink 40 electronic power components 36 via the flowing through the cooling channel 46 refrigerant is possible.

In a first embodiment of a refrigeration system according to the invention, shown in FIG. 3, the refrigerant compressor according to FIG. 1 arranged in a designated as a whole by 50 refrigeration cycle, wherein an output terminal AA of the refrigerant compressor 10 is connected via a first connecting line 52 with a condenser 54, in which a liquefaction of the pressure exiting from the outlet port AA of the refrigerant compressor 10 refrigerant occurs. - -

Further, the condenser 54 is connected via a connecting line 56 with an expansion device 58, on which an evaporator 62 follows, which in turn is connected via a connecting line 64 to the input terminal AE of the refrigerant compressor 10.

The refrigeration cycle 50 is thus a conventional refrigeration cycle, as it is usually present in refrigeration systems.

From the refrigeration circuit 50 branches a control cooling branch 70 for cooling the heat sink 40 from, for example, the connecting line 56 between the condenser 54 and the expansion device 58, wherein a first connecting line 72 of the control cooling branch 70 leads to a switch-on valve 74 of the control cooling branch 70, to which a thermostatic Expansion valve 76 follows, which is connected to the input terminal 42 of the heat sink 40, which is arranged in the control cooling branch 70.

An outlet connection 44 of the heat sink 40 is then followed by a connecting line 78 which leads to an evaporation pressure regulator 80, which in turn via a connecting line 82 with an intermediate pressure port, for example the intermediate pressure port AZ1 of

Refrigerant compressor 10 is connected.

The fact that the connecting line 82 is led to the intermediate pressure port AZ1 has the consequence that the evaporating pressure VD in the heat sink 40 is higher than the suction pressure PS of the refrigerant compressor 10 without regulation of the evaporating pressure regulator 80. For example, the evaporation pressure VD is in the heat sink 40 at least on the pressure PZl of the refrigerant compressor 10, without the evaporation pressure regulator 80 is effective. - -

By the evaporation pressure regulator 80, however, the evaporation pressure VD can be further raised above the intermediate pressure PZ1 of the refrigerant compressor 10.

Such an increase of the evaporation pressure VD in the heat sink 40 has the purpose of ensuring that the self-adjusting in the heat sink 40

Evaporating temperature of the control cooling branch 70 flowing through the refrigerant is above the freezing point temperature of water to prevent icing of the heat sink 40. Preferably, the evaporation pressure VD is set so high that the evaporation temperature is above a dew point temperature of the environment to prevent condensation of water on the heat sink 40.

The reason for this is that either icing of the heat sink 40 or the condensation of water on the heat sink 40 in the short or long term damage to the speed control 34 or the entire engine control 32, especially to short circuits in these, may result.

Thus, the evaporation pressure regulator 80 opens up the possibility of establishing a minimum evaporation temperature in the heat sink 40 via the evaporation pressure VD in the heat sink 40, which temperature does not fall below this even at full cooling capacity of the control cooling branch 70.

The regulation of the cooling capacity in the heat sink 40 is performed by the

Expansion valve 76, which has a temperature at the output terminal 44 of the heat sink 40 detecting temperature sensor 86, the

Expansion valve 76, the temperature at the output terminal 44 of the heat sink 40 transmitted.

Preferably, the expansion valve 76 is a thermostatic

Expansion valve, which controls in accordance with a differential pressure resulting from the difference of a first pressure, generated by a heated in the temperature sensor 86 and a capillary tube 88 to the expansion valve 76 supplied - -

Medium, and a second pressure D2 of the refrigerant present at the input terminal 42 of the heat sink 40 or at the output terminal 44 of the heat sink 40 results.

Such a thermostatic, working with a pressure difference

Expansion valve 76 is on the one hand inexpensive, on the other hand maintenance-free and has a long service life.

However, such a thermostatic or mechanical expansion valve 76 is not controllable by a controller 90 of the control cooling branch 70, so that the following problem occurs when switching on the refrigerant compressor 10.

When switching off the refrigerant compressor 10, the on-valve 74 is closed by the controller 90, so that the pressure in the heat sink maximally set by the evaporating pressure regulator 80

Evaporation pressure VD corresponds.

Preferably, the evaporation pressure regulator 80 is also a mechanical pressure regulator, which regulates to a fixed set reference pressure.

When the refrigerant compressor 10 is switched off, however, the pressure in the heat sink 40 may also fall below the vaporization pressure VD predetermined by the evaporation pressure regulator 80.

If now the refrigerant compressor 10 is turned on, then the switch-on valve 74 is also opened by the controller 90 at the same time.

Since the pressure in the heat sink 40 is equal to or below the evaporation pressure VD, the evaporation pressure regulator 80 remains closed, that is, no refrigerant can flow through the expansion valve 76 and the heat sink 40. - -

In addition, the expansion valve 76 also remains closed because the temperature measured by the temperature sensor 86 of the expansion valve 76 does not indicate any increase.

Since the coolant temperature is approaching, the temperature of the

Although electronic power components 36 increases relatively quickly, although a heating of the heat sink 40, which, however, since no refrigerant flows through the heat sink 40, only with great delay on the temperature sensor 86 can be noticeable, so that still closed the expansion valve 76 as long would remain until at the temperature sensor 86 of the

Temperature rise would be detected.

This heating leads to undesired heating of the electronic power components 16, so that in many cases the drive motor 30 has to be switched off in order to protect the electronic power components 36, but in any case such heating of the electronic power components 36 reduces their life.

For this reason, a bypass line 92 with a built-in throttle 94 is connected in parallel to the expansion valve 76, the throttle 94 may be formed as a nozzle, capillary or as a diaphragm. It can the

Bypass line 92 may be provided with the throttle 94 external or internal.

The bypass line 92 with the built-in throttle 94 now leads to the fact that when starting the refrigerant compressor 10 and opening the on-off valve 74 by the controller 90 despite closed expansion valve 76 due to this bridging parallel bypass line 92, the pressure of the refrigerant in the heat sink 40 through the evaporating pressure 80 set evaporation pressure VD increases, so that due to this pressure increase, the evaporation pressure regulator 80 will open and thus allows a refrigerant flow through the heat sink 40, the - - leads to the fact that the temperature sensor 86 can detect a heating of the heat sink flowing through the heat sink 40 by the heat of the electronic power components very quickly and to open the

Expansion valve 76 leads, so that this assumes the intended control function for the cooling capacity of the heat sink 40.

The first embodiment of the in Fig. 3 already leads shortly after the start of the refrigerant compressor 10 to an at least minimum flow of refrigerant through the heat sink 40, which causes the thermostatic expansion valve 76 receives its control function and in good time before excessive heating of the heat sink 40 to a sufficient cooling of the same the coolant flowing through the heat sink 40 and evaporates in this refrigerant.

A second embodiment of a refrigeration system according to the invention, shown in Fig. 4, insofar as it has the same elements as the first embodiment, provided with the same reference numerals, so that with respect to the description of these elements in full reference may be made to the statements on the first embodiment.

In contrast to the first embodiment, in this embodiment, no bypass line 92 with a throttle 94 parallel to

Expansion valve 76 is provided, but a bypass line 102 with a throttle 104 in parallel to the evaporation pressure regulator 80, which may be provided externally or internally. Furthermore, the throttle 94 as a nozzle,

Capillary line or aperture be formed.

Upon start-up of the refrigerant compressor 10, opening of the on-off valve 74 by the controller 90 and the bypass line 102 and the throttle 104 will also result in a limited minimum refrigerant flow even if the evaporative pressure regulator 80 did not open due to too low a pressure in the heat sink 40 through the heat sink 40, which in turn has the consequence that the temperature sensor 86 through the - -

Contact with the exiting at the output terminal 44 of the heat sink refrigerant can react very quickly to a heating of this refrigerant and thus the thermostatic expansion valve 76 receives the control of the cooling capacity in the heat sink 40.

After a certain start-up time, the pressure in the heat sink 40 then increases at least to the evaporation pressure VD predetermined by the evaporation pressure regulator 80, and when this evaporation pressure VD is exceeded, the evaporation pressure regulator 80 begins to regulate again.

This also ensures that the regulation for the heat sink 40 starts very quickly in the control cooling branch 70 after the refrigerant compressor 10 has started up.

Incidentally, the second embodiment works in the same way as the above-described embodiment, so that this can be fully incorporated by reference.

In a third embodiment of a refrigeration system according to the invention, shown in Fig. 5, those parts which are identical to those of the preceding embodiments, provided with the same reference numerals, so that with respect to the description thereof may be made in full to the comments on the above embodiments.

In contrast to the above embodiments, neither the thermostatic expansion valve nor the mechanical evaporation pressure regulator 80 is associated with a bypass line with a throttle line.

Rather, the mechanical evaporation pressure regulator 80 is replaced by an electrically controlled evaporation pressure regulator 80 ', a through - - A pressure control 110 having a pulse width modulated control signal controlled control valve 112 which is arranged between the connecting line 78 and the connecting line 82 to regulate the evaporation pressure VD in the heat sink 40 to the intended value.

This electrically controlled evaporation pressure regulator 80 'is above the

Control 90, which cooperates with the pressure control 110, controllable so that the pressure control 110 controls the control valve 112 by a corresponding pulse width modulated control signal at starting refrigerant compressor 10 so that this a minimum flow of refrigerant through the

Control cooling branch 70 allows, which ensures that the mechanical expansion valve 76 with its temperature sensor 86 detects a temperature increase of the heat sink 40 flowing through the refrigerant very quickly and thus receives the control of the cooling capacity of the heat sink.

Incidentally, the third embodiment works in the same way as the above-described embodiments, so that they can be fully incorporated by reference.

In a fourth embodiment, shown in FIG. 6, those elements which are identical to those of the preceding embodiment are provided with the same reference numerals, so that with respect to

Description of the same with respect to the comments on the preceding embodiments reference can be made.

In contrast to the third embodiment, an electrically controlled evaporation pressure regulator 80 "with the control valve 112 is also provided, however, the pressure control 110 'is designed such that on the one hand the evaporation pressure VD in the heat sink 40, for example in the connecting line 78, and on the other hand, the pressure in the Connected line 82 and controls the evaporation pressure VD to a minimum pressure according to this pressure difference. - -

This pressure control 110 'can also be controlled by the controller 90, so that a minimal refrigerant flow through the heat sink 40 can be allowed even with a starting refrigerant compressor independently of the pressure in the heat sink 40 by a suitable pulse width modulated control signal for the control valve 112, which ensures that the thermostatic expansion valve 76 with the temperature sensor 86 the

Registers control for the heat sink 40 and only after a certain start-up of the evaporation pressure regulator 80 "adjusts the evaporation pressure VD in the heat sink 40 to the intended evaporation pressure VD.

Incidentally, the fourth embodiment works in the same way as in connection with the above embodiments

described so that the statements in connection with these embodiments may be fully incorporated by reference.

In a fifth embodiment, shown in Fig. 7, are also those parts which are identical to the preceding embodiments, provided with the same reference numerals, so that in terms of

Description thereof to the full extent to the comments on these

Embodiments can be referenced.

In the fifth embodiment, instead of the electric evaporation pressure regulator 80, "an evaporation pressure regulator 80" is provided which has a three-way control valve 122 controlled by a pressure controller 120, which connects either the connection line 78 directly to the connection line 82 or via a throttle 124 to the connection line 82 combines.

This evaporation pressure regulator 80 "'controls, with the pressure controller 120, the three-way control valve 122 corresponding to the pressure in the connection line 82 leading to the port AZ1 of the refrigerant compressor 10. The

Control of the control valve 122 takes place so that already at - -

Switching off the refrigerant compressor 10, the pressure control 120, the control valve 122 is set so that it connects via the throttle 124, the connecting line 78 to the connecting line 82.

If now the refrigerant compressor 10 is turned on, the pressure PZ1 is established at the port AZ1, which, however, is lower than that

desired evaporation pressure VD in the heat sink 40 and it is first lowered by the throttle 124, the pressure in the heat sink 40 also to the pressure PZ1.

However, this has the advantage that a minimal refrigerant flow through the heat sink 40 in a start-up phase of the refrigerant compressor 10 can be ensured thereby, so that immediately after the start of the refrigerant compressor 10, the mechanical expansion valve 76 with the temperature sensor 86 is fully functional.

After the start-up phase, the three-way control valve 122 is then switched to a pulse-width-modulated operation with regulation of the evaporation pressure in the heat sink 40 to the specified value VD.

Claims

1. refrigeration system comprising a refrigeration cycle (50) in which a refrigerant compressor (10), a condenser (54) following the refrigerant compressor (10), an expansion device (58) following the condenser (54) and an expansion device (58) the following evaporator are arranged, which in turn is connected to the refrigerant compressor (10), wherein the refrigerant compressor (10) has a speed controlled by an electronic engine controller (32) drive motor (30) and a refrigerant flowing through

A control cooling branch (70) branched from the refrigeration circuit (50) between the condenser (54) and the expansion device (58) and led to a port (AZ) of the refrigerant compressor (10), and in which a power electronic component (36) of FIG Motor controller (32) thermally conductively connected heat sink (40) is arranged,

characterized in that a control for the control cooling branch (70) is provided which controls during operation of the refrigerant compressor (10) a temperature of the heat sink (40) so that a minimum evaporation temperature of the heat sink (40) above a freezing point temperature and below a condensing temperature of the refrigerant in the Condenser (54) is located.

2. Refrigeration system according to claim 1, characterized in that the

Minimum evaporation temperature of the heat sink (40) above a dew point of an environment of the engine control (32).

3. refrigeration system according to claim 1 or 2, characterized in that the temperature of the heat sink (40) at least at a by an evaporation pressure (VD) of the refrigerant in the heat sink (40) adjustable minimum evaporation temperature or higher.

4. Refrigeration system according to one of the preceding claims, characterized in that in a start-up phase of the refrigerant compressor (10) a minimal refrigerant flow through the heat sink (40) flows.

5. Refrigeration system according to one of the preceding claims, characterized

characterized in that the control in the start-up phase of the refrigerant compressor (10) a minimum flow of refrigerant through the

Control cooling branch (70) allows.

6. Refrigeration system according to one of the preceding claims, characterized

characterized in that the adjustment of the evaporation pressure (VD) in the heat sink (40) by an evaporation pressure regulator (80).

7. refrigeration system according to claim 6, characterized in that the evaporation pressure regulator (80) controls the evaporation pressure (VD) in the heat sink (40) so that it is above a pressure (PZ) at the port (AZ) of the refrigerant compressor (10), to which the control cooling branch (70) is connected.

8. Refrigeration system according to one of claims 6 to 7, characterized in that the evaporation pressure regulator (80) in the start-up phase when switching on the refrigerant compressor (10) the minimum

Refrigerant flow through the control cooling branch (70) passes.

9. Refrigeration system according to one of the preceding claims, characterized

characterized in that the evaporation pressure regulator (80) in the

Switching on the refrigerant compressor (10) in the start-up phase

is ineffective.

10. Refrigeration system according to one of claims 8 or 9, characterized in that the evaporation pressure regulator (80) is associated with a bypass line (102) having a throttle (104).

11. A refrigeration system according to claim 8 or 9, characterized in that the evaporation pressure regulator (80) comprises a control valve (112, 122) and a pressure control (110, 120) for the control valve (112, 122) and that the pressure control (110, 120 ) operates in the start-up phase of the refrigerant compressor (10) so as to allow the minimum refrigerant flow.

12. Refrigeration system according to one of the preceding claims, characterized

characterized in that the connection (AZ) of the refrigerant compressor (10) to which the Strömungskühlungszwelfg (70) is connected, is at a pressure level, which is above the pressure level (PS) of the

Connection (AE) of the refrigerant compressor (10) which is connected to the evaporator (62).

13. Refrigeration system according to one of the preceding claims, characterized

in that the control cooling branch (70) comprises a thermostatic expansion valve (76) connected upstream of the heat sink (40) and controlled by a temperature sensor (86) on the heat sink (40).

14. Refrigeration system according to claim 13, characterized in that the

Temperature sensor (86) is arranged at an output terminal (44) of the heat sink (40).

15. Refrigeration system according to claim 13 or 14, characterized in that the thermostatic expansion valve (76) is assigned a bypass line (92) with a throttle (94).