SINGLE-CIRCUIT REFRIGERATOR

Abstract

A single-circuit refrigerator includes a refrigerant circuit in which the following are connected in series one after another between a pressure port and an intake port of a compressor: a condenser, a first throttle section, a first evaporator for cooling a first temperature zone of the single-circuit refrigerator, a second throttle section, a second evaporator for cooling a second temperature zone of the single circuit refrigerator, and an intake line. A downstream section of the intake line is connected with the first throttle section to form a first heat exchanger, and an upstream section of the intake line is connected with the second throttle section to form a second heat exchanger.

Claims

1-7. (canceled)

8. A single-circuit refrigerator, comprising: first and second temperature zones; a compressor having a pressure port and an intake port; a refrigerant circuit including: a condenser, a first throttle section, a first evaporator for cooling said first temperature zone, a second throttle section, a second evaporator for cooling said second temperature zone, and an intake line, being connected in series one after another between said pressure port and said intake port of said compressor; said intake line having a downstream section connected with said first throttle section to form a first heat exchanger; and said intake line having an upstream section connected with said second throttle section to form a second heat exchanger.

9. The single-circuit refrigerator according to claim 8, wherein said second throttle section has a line section, and an adhesive connects said line section with said upstream section of said intake line.

10. The single-circuit refrigerator according to claim 9, wherein said adhesive is an adhesive tape.

11. The single-circuit refrigerator according to claim 8, wherein said second throttle section has a line section running inside said upstream section of said intake line.

12. The single-circuit refrigerator according to claim 8, wherein said second throttle section has a line section coiled around said upstream section of said intake line.

13. The single-circuit refrigerator according to claim 9, wherein said line section of said second throttle section is a capillary.

14. The single-circuit refrigerator according to claim 11, wherein said line section of said second throttle section is a capillary.

15. The single-circuit refrigerator according to claim 12, wherein said line section of said second throttle section is a capillary.

16. The single-circuit refrigerator according to claim 8, wherein said second throttle section has an adjustable conductance.

17. The single-circuit refrigerator according to claim 8, wherein said second throttle section has a controllable expansion valve.

Description

[0023] Further features and advantages of the invention will emerge from the description which follows of exemplary embodiments, with reference to the attached diagrams. In these:

[0024] FIG. 1 shows a schematic diagram of the refrigerant circuit of an inventive refrigerator;

[0025] FIG. 2 shows a schematic section through the housing of the refrigerator;

[0026] FIG. 3 shows a first embodiment of a heat exchanger of the refrigerator,

[0027] FIG. 4 shows a second embodiment of the heat exchanger, and

[0028] FIG. 5 shows a third embodiment of the heat exchanger.

[0029] The refrigerant circuit shown in FIG. 1 comprises a speed-regulated compressor 1 with a pressure port 2 and an intake port 3. A refrigerant line 4 exiting the pressure port 2 runs in the direction of circulation of the refrigerant initially via a condenser 5 and a first throttle section 6, implemented in this case in the standard way as a capillary line 7, to a first evaporator 8. A second throttle section 9 with adjustable conductance is located on the refrigerant line 4 between an outlet port of the first evaporator 8 and an inlet port of a second evaporator 10. An intake line 11 extends from an outlet port of the evaporator 10 to the intake port 3 of the compressor 1.

[0030] As can be seen more clearly in the schematic section in FIG. 2, the evaporator 8 lying upstream along the refrigerant line 4 cools a normal cooling compartment 16 and the evaporator 10 lying downstream cools a freezer compartment 17 of a domestic refrigerator.

[0031] With reference again to FIG. 1, the second throttle section 9 comprises a line section 18 and a controllable expansion valve 22 connected in series with the line section 18. The line section 18 may have a similar line cross-section like the refrigerant line of the evaporator 6, but may however also be formed by a capillary like the first throttle section 6.

[0032] The line section 18 designed as a capillary is preferably long enough to ensure a drop in pressure between the evaporators 8, 10, which corresponds to a difference in the evaporation temperatures of the evaporators 8, 10 of several C., even if the expansion valve 22 is fully open. Therefore, within the adjustment range of the expansion valve 22, it is possible for the difference in pressure between the evaporators 8, 10 to be controlled more precisely than if this difference in pressure had to be maintained by the expansion valve 22 alone.

[0033] An upstream section 12 of the intake line 11 is thermally bonded with the second throttle section 9 to form a heat exchanger 14; a downstream section 13 of the intake line 11 forms a further heat exchanger 15 together with the first throttle section 6.

[0034] A temperature sensor 19 or 20 is disposed on each of the compartments 16, 17. The temperature sensors 19, 20 are connected to a control unit 21, which controls the rotation speed of the compressor 1 and the degree of opening of the expansion valve 22 by comparing the temperatures reported by the temperature sensors 19, 20 with target temperatures for the compartments 16, 17 that are set by a user. If, for example, the temperature sensor 19 indicates a cooling requirement in the normal cooling compartment 16, i.e. if the temperature in the normal cooling compartment 16 is at the upper end of a tolerance interval around the target temperature set by the user, then the control unit 21 checks the temperature of the freezer compartment 17. If this is in the upper section of a tolerance interval around the set target value of the latter, the control unit 21 increments the rotation speed of the compressor 1 so that both compartments 16, 17 are cooled more intensively; if, on the other hand, the temperature of the freezer compartment 17 is in the lower section of the tolerance interval, so that more intensive cooling would result in the tolerance interval being exceeded at the lower end, then the control unit increments the degree of opening of the second throttle section 9, so that the pressure in the evaporator 8 is reduced. The overall cooling performance remains essentially unchanged as a result, but the share of overall cooling performance increases in relation to the normal cooling compartment 16, so that it can be cooled without at the same time causing excessive cooling in the freezer compartment 17.

[0035] Accordingly, if the temperature in the freezer compartment 17 reaches the upper end of the tolerance range, the control unit 21 determines, on the basis of the temperature of the normal cooling compartment 16, whether the rotation speed of the compressor 1 is incremented in order to cool both compartments 16, 17 more intensively, or whether the degree of opening of the second throttle section 9 is reduced in order to increase the share of overall cooling performance relating to the freezer compartment.

[0036] If the temperature of the normal cooling compartment 16 reaches the lower end of the tolerance range, on the basis of the freezer compartment temperature it is determined whether the rotation speed of the compressor 1 decrements or the degree of opening of the second throttle section 9 is decremented, and in the event that the freezer compartment reaches the lower end of the tolerance range, a decision must be made between decrementing the compressor rotation speed and incrementing the degree of opening of the second throttle section 9.

[0037] A control unit equivalent to the one described above for the compressor 1 and the expansion valve 22 can also be implemented by means of a PID module.

[0038] The series connection of the two heat exchangers 14, 15 along the intake line 11 causes the refrigerant vapor extracted from the evaporator 10 of the freezer compartment 17, on reaching the heat exchanger 15, to already have a temperature that corresponds approximately to the evaporation temperature in the evaporator 8. The evaporation in the capillary 7 of the first throttle section 6 is therefore not completely suppressed, so that a small quantity of vapor is constantly present in the capillary 7 and limits the mass throughput thereof. In this way, noise-intensive oscillations of the mass throughput, which may occur in particular if the capillary 7 is free of vapor and its mass throughput exceeds that of the compressor 1 until a supply of liquid refrigerant in the condenser is expended and only refrigerant vapor can flow back into the capillary, are avoided.

[0039] To establish a close thermal contact between the line section 18 and the upstream section 12 of the intake line 11, the two can be surrounded by an adhesive tape 23, preferably an aluminum adhesive tape with good thermal conductivity, as outlined in FIG. 3.

[0040] In another embodiment of the heat exchanger 14, the line section 18 extends within the interior of the intake line 11, as shown in FIG. 4

[0041] Consequently, in a further alternative, as shown in in FIG. 5, the line section 18 may be coiled around the upstream section 12 of the intake line 11, in order to form the heat exchanger 14.

[0042] The expansion valve 22 may, according to a variant that is not shown, be formed by a directional valve and a number of capillary sections of different lengths, one of which in each case is linked into the refrigerant circuit by the directional valve.

REFERENCE CHARACTERS

[0043] 1 Compressor [0044] 2 Pressure port [0045] 3 Intake port [0046] 4 Refrigerant line [0047] 5 Condenser [0048] 6 Throttle section [0049] 7 Capillary [0050] 8 Evaporator [0051] 9 Throttle section [0052] 10 Evaporator [0053] 11 Intake line [0054] 12 Upstream section [0055] 13 Downstream section [0056] 14 Heat exchanger [0057] 15 Heat exchanger [0058] 16 Normal cooling compartment [0059] 17 Freezer compartment [0060] 18 Line section [0061] 19 Temperature sensor [0062] 20 Temperature sensor [0063] 21 Control unit [0064] 22 Expansion valve [0065] 23 Adhesive tape