REFRIGERATION APPLIANCE WITH COMPARTMENTS THAT CAN BE HEATED AND COOLED

Abstract

A refrigeration appliance, especially domestic refrigeration appliance, includes a compressor, a condenser, at least a first evaporator, a suction line from the first evaporator to the compressor, at least one heat exchanger switchable between condenser operation and evaporator operation, and a valve arrangement switching the heat exchanger between an evaporator operating state, having a switchable heat exchanger inlet connected to the condenser through a first choke point and a switchable heat exchanger outlet connected to the first evaporator, and a condenser operating state, having the switchable heat exchanger outlet connected to the evaporator through a second choke point. A first supply line for supplying refrigerant in the evaporator operating state and a second supply line, separate therefrom, for supplying refrigerant in the condenser operating state, are associated with the switchable heat exchanger. Only the first supply line is connected with the suction line, forming an external heat exchanger.

Claims

1-12. (canceled)

13. A refrigeration appliance or household refrigeration appliance, comprising: a compressor; a condenser; at least one first evaporator; a suction line running from said at least one first evaporator to said compressor; at least one heat exchanger having an inlet and an outlet and being switchable between condenser and evaporator operation; first and second choke points; and a valve arrangement for switching said at least one switchable heat exchanger between an evaporator operating state having said inlet of said at least one switchable heat exchanger connected to said condenser through said first choke point and said outlet of said at least one switchable heat exchanger connected to said at least one first evaporator, and a condenser operating state having said outlet of said at least one switchable heat exchanger connected to said at least one evaporator through said second choke point; and a first supply line and a second supply line being separate from each other and associated with said at least one switchable heat exchanger, said first supply line configured for supplying refrigerant in said evaporator operating state and said second supply line configured for supplying refrigerant in said condenser operating state, and only said first supply line being connected to said suction line to form an internal heat exchanger.

14. The refrigeration appliance according to claim 13, wherein said second choke point includes a controlled expansion valve.

15. The refrigeration appliance according to claim 13, wherein said at least one switchable heat exchanger is connected in parallel with said condenser in said condenser operating state.

16. The refrigeration appliance according to claim 13, wherein said valve arrangement includes a valve configured to be shut off at said first supply line.

17. The refrigeration appliance according to claim 13, wherein said at least one switchable heat exchanger includes two switchable heat exchangers configured to be switched between said evaporator operating state and said condenser operating state independently of one another.

18. The refrigeration appliance according to claim 17, which further comprises first and second compartments, said first compartment having a volume being between 150% and 250% of a volume of said second compartment, and said two switchable heat exchangers being configured to heat or to cool said first and said second compartments.

19. The refrigeration appliance according to claim 17, wherein said compressor has an outlet, and said valve arrangement includes a directional valve being closed in said evaporator operating state and, in said condenser operating state of at least one of said two switchable heat exchangers, connecting said inlet of said at least one heat exchanger to said outlet of said compressor, at least for a time.

20. The refrigeration appliance according to claim 17, wherein said compressor has an outlet, said two switchable heat exchangers are first and second heat exchangers, and said valve arrangement is configured to be switched in a clocked manner between a first open position connecting said outlet of said compressor to said inlet of said first heat exchanger, and a second open position connecting said outlet of said compressor to said inlet of said second heat exchanger.

21. The refrigeration appliance according to claim 13, which further comprises a second evaporator connected in series upstream of said first evaporator and connected in parallel with said at least one switchable heat exchanger.

22. The refrigeration appliance according to claim 21, which further comprises a third choke point, said at least one first evaporator and said second evaporator being connected through said third choke point.

23. The refrigeration appliance according to claim 22, wherein said third choke point includes a controlled expansion valve.

24. The refrigeration appliance according to claim 21, which further comprises a connection line between said at least one first evaporator and said second evaporator being connected to said suction line to form a section of said internal heat exchanger.

Description

[0021] FIG. 1 shows a block diagram of a refrigeration appliance according to the invention.

[0022] In a thermally insulating housing, the refrigeration appliance in FIG. 1 comprises a cold cooled compartment 1, typically a freezer compartment, a warm cooled compartment 2, typically a normal refrigeration compartment, as well as a first and a second flexible, i.e., optionally coolable and heatable, compartment 3, 4.

[0023] A refrigerant line 7, which starts from an outlet 5 of a compressor 6, first reaches a frame heater 9 and a condenser 10 via a branching point 8. A fan 26 may be assigned to the condenser 10 in order to control its power. At a further branching point 11 downstream of the condenser 10, the refrigerant line 7 branches off into three branches 12a-c. In each branch 12a-c, the following follow one another: a valve 13a-c, a supply line 14a-c, which may be embodied as a capillary, a heat exchanger 15a, b or an evaporator 15c and a controlled expansion valve 16a-c. The heat exchangers 15a, b are each in thermal contact with one of the compartments 3, 4; the evaporator 15c is in contact with the compartment 2. There are not necessarily structural differences between the evaporator 15c and the heat exchangers 15a, b; both may be identical or merely different from one another in terms of their dimensions. Typically, the heat exchangers 15a, b and the evaporator 15c are embodied as finned heat exchangers of a per se known construction, in which in each case a large number of mutually parallel fins are merged to form a block, the refrigerant line 7 crosses the fins in a meandering manner and air circulates in the intermediate spaces between the fins, and each finned heat exchanger is assigned a fan 17a-c, which controls the intensity of the air circulation and therefore the thermal power exchanged with the compartment 2, 3 or 4 assigned in each case.

[0024] Downstream of the expansion valves 16a-c, the three branches 12a-c merge at a junction 18. The junction 18 may lie upstream of an evaporator 19 that cools the compartment 1; preferably, it is located in the evaporator 19 itself, i.e., the evaporator 19 possesses an inlet for each branch 12a-c. In the same way as the fans 17a-c, the evaporator 19 is also assigned a fan 27.

[0025] Starting from an outlet of the evaporator 19, a suction line 20 runs to an inlet 21 of the compressor 6. The suction line 20, together with a connection line 22 of the branch 12c lying downstream of the evaporator 15c as well as with the supply lines 14a-c, forms an internal heat exchanger 23, in which the refrigerant vapor circulating in the suction line 20 is first heated in thermal contact with the connection line 22 and subsequently in thermal contact with the supply lines 14a-c. For this purpose, the connection line 22 and the supply lines 14a-c may be fastened to the surface of the suction line 20 or guided in the interior thereof.

[0026] An inlet of a directional valve 24 is connected to the branching point 8. The directional valve 24 has an outlet in each case, which is connected to the inlet of the heat exchanger 15a or 15b via a supply line 25a or 25b in each case, and can be switched between the closed position, a position open toward the heat exchanger 15a and a position open toward the heat exchanger 15b.

[0027] With the construction described above, a large number of operating states can be realized:

[0028] In a first operating state, the position open toward the heat exchanger 15a and the closed position of the directional valve 24 alternate with one another, the valve 13a is closed, and the expansion valve 16a is controlled, in order to maintain a high-pressure difference between the heat exchanger 15a and the evaporator 19. Thus, in each open phase of the directional valve 24, warm, dense refrigerant from the compressor 6 is applied to the heat exchanger 15a, and the condensation taking place in the heat exchanger 15a heats the compartment 3. This means that the first operating state is a condenser operating state of the heat exchanger 15a.

[0029] In this context, refrigerant liquefied in the heat exchanger 15a reaches the evaporator 19 via the expansion valve 16a, evaporates again at the evaporator 19 and thus cools the compartment 1.

[0030] In each closed phase of the directional valve 24, dense refrigerant vapor reaches the condenser 10, where it condenses. The liquid refrigerant obtained in this way is distributed via the valves 13b, 13c to the supply lines 14b, 14c or the heat exchanger 15b and the evaporator 15c, meaning that evaporation takes place there and the compartments 2, 4 are cooled, i.e. the first operating state is an evaporator operating state for the heat exchanger 15b. Liquid refrigerant not consumed in the heat exchanger 15b or evaporator 15c reaches the evaporator 19 via one of the expansion valves 16b, 16c, thus contributing to the cooling of the compartment 1.

[0031] The level of the heating power (or its operating temperature) released in compartment 3 is determined on the one hand by the duty factor of the position of the valve 13a in which it is open toward the heat exchanger 15a, and on the other hand by the rotational speed of the fan 17a; the slower this runs, the slower the condensation, and the less refrigerant vapor can flow into the heat exchanger 15a, despite the open valve 13a, and the more refrigerant vapor therefore has to take the path via the condenser 10.

[0032] The mass flow rate via the compressor 10 is therefore variable over time, and with it also the pressure drop at the supply lines 14b, 14c. In order to still be able to keep the heat exchanger 15b and the evaporator 15c at a desired evaporation pressure, it is recommended to use controlled expansion valves as valves 13a-c, which are not only able to shut off their branch 12a-c on demand, but also maintain a predefined pressure difference in the open state.

[0033] It is also conceivable, however, to tolerate fluctuations in the evaporation pressure in heat exchanger 15b and evaporator 15c associated with the variable mass flow rate and to keep an operating temperature of the compartments 2, 4 constant by reducing the rotational speed of the fans 17b, c when the evaporation temperature drops or increasing it when the evaporation temperature rises.

[0034] Thus, in the first operating state, different operating temperatures below the ambient temperature can be maintained in the compartments 1, 2, 4, wherein the operating temperature of the compartment 2 may be higher or lower than that of the compartment 4. Both the refrigerant flowing toward the evaporator 15c and flowing away from it run through the internal heat exchanger 23; likewise, the refrigerant on the way to the heat exchanger 15b, meaning that all refrigerant, the heat of which is not needed to heat a compartment, runs through the internal heat exchanger 23.

[0035] The same applies for a second operating state, in which the position open toward the heat exchanger 15b and the closed position of the directional valve 24 alternate with one another and the valve 13b is closed, meaning that the compartment 4 is heated and the compartment 3 is cooled, i.e., the second operating state is an evaporator operating state for the heat exchanger 15a and a condenser operating state for the heat exchanger 15b.

[0036] The compartments 3, 4 have different sizes, thus a user can make the selection between the first and the second operating state on the basis of the space requirement of the item to be kept warm. This means that the volume of the compartment 3 may amount to between 150 and 250% of the volume of the compartment 4, or vice versa.

[0037] In a third operating state, the position open toward the heat exchanger 15a, the position open toward the heat exchanger 15b and the closed position of the directional valve 24 alternate with one another. Both compartments 2, 3 are heated, i.e., both heat exchangers 15a, 15b are in the condenser operating state. As both valves 13a, 13b are closed, no heat exchange takes place via the supply lines 14a, 14b in the internal heat exchanger 23; only the flow running via the evaporator 15c is available for the preheating of the drawn-in refrigerant. Via the duty factors of the phases open toward the heat exchanger 15a or toward the heat exchanger 15b, it is possible for the heating power allotted to each compartment 3, 4 to be controlled and for different operating temperatures to be set for the two compartments 3, 4, if desired.

[0038] In a fourth operating state, the directional valve 24 is permanently in the closed position. The valves 13a, 13b are open, the heat exchangers 15a, 15b are in the evaporator operating state and cool the compartments 3, 4. Refrigerant on the way to the heat exchangers 15a, 15b runs through the supply lines 14a, 14b and thus also the internal heat exchanger 23.

[0039] Thus, on the one hand, heat losses and condensation of the refrigerant before reaching the heat exchanger 15a or 15b is avoided when it works in the condenser operating mode; on the other hand, a higher degree of efficiency is achieved in the evaporator operating mode.

REFERENCE CHARACTERS

[0040] 1 Compartment [0041] 2 Compartment [0042] 3 Compartment [0043] 4 Compartment [0044] 5 Outlet [0045] 6 Compressor [0046] 7 Refrigerant line [0047] 8 Branching point [0048] 9 Frame heater [0049] 10 Condenser [0050] 11 Branching point [0051] 12a-c Branch [0052] 13a-c Valve [0053] 14a-c Supply line [0054] 15a-c Heat exchanger/heat exchanger/evaporator [0055] 16a-c Expansion valve [0056] 17a-c Fan [0057] 18 Junction [0058] 19 Evaporator [0059] 20 Suction line [0060] 21 Inlet [0061] 22 Connection line [0062] 23 Internal heat exchanger [0063] 24 Directional valve [0064] 25a-c Supply line [0065] 26 Fan