DE102012206803A1 - Cold apparatus i.e. household cold apparatus, for storing goods to be cooled, has control unit reversible into mode in which control unit switches compressor, when predetermined cycle time is elapsed from preceding switching operation - Google Patents

Abstract

The apparatus has a freezing storage compartment (2) cooled by a vaporizer (5) i.e. cold wall vaporizer, which is connected with a compressor (7) in a refrigerant circuit. A control unit (11) is connected with a vaporizer temperature sensor (13), and switched-on in an operation mode i.e. super cooling mode, of the compressor when temperature detected by the sensor exceeds switching-on temperature. The control unit is reversible into another operation mode in which the control unit switches the compressor, when a predetermined cycle time is elapsed from the preceding switching operation.

Description

The present invention relates to a refrigeration appliance, in particular a domestic refrigeration appliance, with at least one first storage compartment for refrigerated goods, which is cooled by a first evaporator connected to a compressor in a refrigerant circuit. Such refrigerators usually have a temperature sensor and connected to the temperature sensor control unit which is set to turn on the compressor when the temperature detected by the temperature sensor rises above a switch-on, and turn it off again when the temperature has fallen below the compressor operation below a switch-off , In this way, the temperature of the storage compartment can be kept in a suitable range for the stored therein refrigerated goods.

If refrigerated goods are reloaded into the storage compartment while the compressor is off, and this refrigerated goods initially has a temperature above the target range, then the heat of the new refrigerated goods must first be distributed in the storage compartment to reach the temperature sensor and there is an increase over to effect the switch-on threshold. In the period between the loading and the switching on of the compressor is no cooling capacity for cooling down the new chilled goods available; the cooling of the new chilled goods taking place during this time is associated with a warming up of the previously existing storage compartment. The heating of the existing chilled goods can affect its durability. A slow cooling of the newly stored refrigerated goods is not beneficial to its durability.

It would therefore be desirable per se to be able to switch on the compressor of a refrigerator at any time, so that a user can activate it simultaneously with the loading of new refrigerated goods and thereby provide cooling capacity available. However, there is the problem that a pressure difference between the suction and pressure connection of the compressor, especially in modern, energy-efficient refrigerators persists after switching off the compressor for a long time, and that most compressors used in refrigerators are not able to oppose such To start pressure difference. To do this, the compressor needs to be stronger and more powerful than usual, which increases the manufacturing cost of the refrigerator and reduces energy efficiency.

The object of the invention is therefore to provide a refrigerator which is able to start its compressor at a desired time, and yet allows the use of a low-cost, energy-efficient compressor.

The object is achieved by providing the control unit between a first operating mode, in a refrigerator with at least a first storage compartment, which is cooled by a first evaporator connected to a compressor in a refrigerant circuit, a first temperature sensor and a control unit connected to the first temperature sensor it turns on the compressor when the temperature detected by the first temperature sensor rises above a switch-on temperature, and is switchable to a second operating mode in which it switches on the compressor whenever a predetermined cycle time has elapsed since a previous switch-on. By turning on the compressor in the second mode of operation, instead of being temperature controlled, the turn-on times become predictable, so that when the second mode of operation is activated at the appropriate time prior to intentional loading of new refrigerated goods, it can be ensured that the compressor will start at the intended time of loading and thus Cooling capacity is available immediately.

The control unit is preferably set up to return to the first operating mode after a predetermined dwell time in the second operating mode.

If the time interval between the times when the control unit turns on the compressor during the second operating mode and the end of the predetermined dwell time is an integer multiple of the cycle time, then it is ensured that the compressor is switched off immediately before the end of the dwell time, and if the residence time has elapsed, the pressure difference between the connections of the compressor has been reduced so that it can start immediately.

The control unit can therefore be set up to switch on the compressor unconditionally at the end of the dwell time.

In the event that the new refrigerated goods can not be invited exactly to the previously planned time, it is expedient if the refrigerator has a door and a door sensor for detecting an actuation of the door and the control unit is set during a time window at the end of the residence time then turn on the compressor when the door sensor detects an actuation of the door. Since the door has to be actuated to load the new chilled goods, the likelihood is high that in this way a start of the compressor is exactly synchronized with the loading of the new chilled goods.

The invention is particularly advantageously applicable to a so-called single-circuit Refrigerating appliance, ie a refrigeration device which has a cooled by a second evaporator second storage compartment and in which the second evaporator is connected downstream of the first evaporator in the refrigerant circuit. If in such a refrigerator, the above-mentioned first temperature sensor is disposed on the second storage compartment, the loading of new refrigerated goods in the first storage compartment on the temperature of the sensor does not affect, so that in such a refrigerator when the operation of the compressor is purely temperature-controlled the time between loading new chilled goods into the first storage compartment and a subsequent start of the compressor can become extremely long.

In order to preferably cool the first storage compartment in such a refrigeration device in the second operating mode, the control unit may be configured to switch off the compressor in the second operating mode before the amount of liquid refrigerant produced since the last activation is sufficient to fill the first and the second evaporator. In this way, in the second operating mode, at most a small amount of liquid refrigerant reaches the second evaporator in each switch-on phase of the compressor. The first storage compartment can therefore be cooled down strongly and quickly, without this leading to excessive cooling of the second storage compartment. This is particularly important if the second storage compartment is a standard refrigerated compartment that may contain refrigerated goods which will be damaged at a temperature below 0 ° C and therefore should not be cooled below freezing, whereas the first storage compartment may be e.g. a freezer or a 0 ° compartment can be.

In order to be able to efficiently cool the first storage compartment in the second operating mode and at the same time to avoid cooling of the second storage compartment, the amount of liquid refrigerant which the compressor generates between switching on and the subsequent switching off should correspond as closely as possible to the capacity of the first evaporator and in particular at least half and at most 1.5 times the capacity of the first evaporator.

Such a dosage of the refrigerant generation can be realized in a simple manner in that the control unit is set up to switch off the compressor again if a predetermined operating time has elapsed since the last activation.

Switching off the compressor in the second operating mode can also be temperature-controlled; Preferably, for this purpose, a second temperature sensor in a downstream region of the first evaporator, an upstream region of the second evaporator or a refrigerant line connecting the evaporator is arranged, and the control unit is adapted to turn the compressor off again when the temperature detected by this second temperature sensor is the arrival of indicates liquid refrigerant at its installation location. Depending on the placement of the second temperature sensor, the compressor can be switched off again in this way, just before liquid refrigerant penetrates into the second compressor, or shortly after a small amount of liquid refrigerant has reached the second evaporator.

The duration of a non-operating time of the compressor in the second operating mode should be at least long enough to allow such a degree of pressure equalization between the condenser and evaporators that the compressor can then restart trouble-free. In addition, over the duration of the non-operating time can affect the distribution of cooling capacity on the evaporator: the longer the non-operating time, the smaller is the proportion of liquid refrigerant remaining in the first evaporator and in a subsequent operating time passes the second evaporator. Therefore, it is possible to select the duration of the non-operating time so that a desired critical value of the temperature in the storage compartment cooled by the second evaporator is not undershot. Conveniently, the duration of the non-operating time is selected so that the second storage compartment does not freeze in the second operating mode.

The first mode of operation may be a normal cooling mode in which a switch-on threshold above which the compressor is switched on and a switch-off threshold below which it is switched off are derived from a setpoint temperature set by a user at a controller. However, it is especially expedient if the first operating mode is a super-cooling mode in which the switch-on threshold is lower than a setpoint temperature of the second storage compartment set by the user for the normal cooling mode.

Further features and advantages of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. From this description and the figures also show features of the embodiments, which are not mentioned in the claims. Such features may also occur in combinations other than those specifically disclosed herein. Therefore, the fact that several such features are mentioned in the same sentence or in a different type of textual context does not justify the conclusion that they can occur only in the specific combination disclosed; instead, it is generally to be assumed that individual ones of several such features are also omitted or modified can, if this does not affect the functionality of the invention in question. Show it:

1 a schematic representation of a refrigeration device according to the invention;

2 the changeover of compressor operating and non-operating times in different operating modes of the refrigeration device; and

3 a flowchart of a method of operation of a control circuit of the refrigerator.

1 schematically shows a single-circuit household refrigerator with a heat-insulating housing 1 whose interior is in two storage compartments, here a freezer 2 and a normal refrigerator 3 , is divided. The subdivision is here a wall 4 that like the subjects 2 . 3 surrounding walls of the housing 1 filled with insulating material and at the

Front edge of the freezer compartment, not shown in the figure 2 and the normal refrigerator 3 in closed position. The two subjects 2 . 3 but could also be closed by a common door that extends over the front edge of the wall 4 extends. In the latter case, the freezer 2 still be associated with an interior door, which is the standard refrigerator 3 separates.

Both subjects 2 . 3 is each an evaporator 5 . 6 assigned. The evaporators 5 are shown here as a coldwall evaporator, but there are also other types of evaporators into consideration. The evaporators 5 . 6 can be on separate boards or even on a single wall 4 bridging over both partitions 2 . 3 be formed extending board.

The evaporators 5 . 6 Both are part of a refrigerant circuit, which further in a conventional manner a compressor 7 , for example, on a rear wall of the housing 1 attached liquefier 8th , a dryer 9 and a capillary 10 includes. Refrigerant in the compressor 7 has been condensed and heated, gives its heat to the condenser 8th and condenses. The liquid refrigerant relaxes as it passes through the capillary 10 and reached from there first the evaporator 5 of the freezer compartment 2 where it can evaporate under low pressure. The evaporator 6 closes downstream to the evaporator 5 on, and its output is connected to a suction port of the compressor 7 connected.

A control circuit 11 To switch on and off the compressor is switchable between different operating modes. In a normal cooling mode, it controls the operation of the compressor 7 based on measured values of the temperature Tnk of the standard refrigerator compartment 3 by a temperature sensor 13 be supplied, and a target temperature of the normal cooling compartment 3 , which is adjustable by a user in a conventional manner to a designated controller.

The measured value of the air temperature sensor 13 should as accurately as possible the air temperature in the normal refrigeration compartment 3 play. For this purpose, the air temperature sensor 13 in a wall of the housing 1 between their insulation material filling and a normal cooling compartment 3 delimiting inner container removed from the evaporator 6 arranged.

In normal cooling mode, the control circuit switches 11 the compressor 7 when the temperature Tnk exceeds a turn-on threshold slightly above the user-set setpoint temperature and turns on the compressor 7 again off, if a switch-off threshold, slightly below the set temperature, falls below.

The freezer 2 has no temperature sensor, therefore, the control unit 11 not readily respond to when the freezer 2 is heated by a larger amount re-invited refrigerated goods.

To invite a larger amount of refrigerated goods in the freezer 2 to prepare, the user is held, in time before the intended loading time, for example, with a flow D of 24 hours, one with the control circuit 11 connected operating mode selector switch 17 to press. This causes the transition of the control circuit 11 in the super-cooling mode, in which the switch-on and switch-off for the compressor operation is no longer derived from the setpoint temperature set by the user, but from a predetermined by the manufacturer of the device temperature, which is preferably just above freezing. 2 shows the effects of such switching on the operation of the compressor 7 , During normal operation, in a time interval [t0, t1], medium duration operating phases Δt1 suffice for the normal refrigeration compartment 3 cool down to the turn-off, and it passes a relatively long Nichtbetriebsphase .DELTA.t0 until the turn-on threshold is reached again. Switching to the super cooling mode at time t1 first causes an extremely long operating phase .DELTA.t1 * of the compressor, in which this the normal refrigeration compartment 3 Cools from the user-defined setpoint temperature to the low setpoint temperature. The non-operating phases Δt0 'of the compressor are significantly shortened due to the higher temperature difference from the environment and the thereby amplified heat flow from the outside in the super-cooling operating mode. Even after cooling to the low setpoint temperature longer operating phases .DELTA.t1 'of the compressor 7 as in Normal cooling mode required to set the low set point temperature in the normal cooling compartment 3 to keep.

The freezer 2 Although in the super-cooling mode of operation, due to the higher proportion of compressor operating times in the total operating time, it is cooled more than in the normal cooling mode and reaches a lower temperature, the extent of the achievable cooling is limited by the need for the normal refrigeration compartment 3 should not cool below 0 ° C.

To cool the freezer compartment 2 to allow under the reachable in super cooling mode limit temperature, the control circuit switches 11 at time t2 into a selective cooling operation mode in which, compared to the normal cooling mode, short phases Δt0 of "non-operation and short phases Δt1" of the operation of the compressor 7 alternate with each other. The length of the operating phases Δt1 "is such that they are sufficient to the evaporator 5 to fill with liquid refrigerant again, but not the evaporator 6 , The length of the non-operational phases Δt0 "is sized to be sufficient to accommodate the evaporator 5 has been filled with liquid refrigerant in the previous operating phase, to allow it to evaporate so far that in the subsequent operating phase only small residues of this refrigerant in the evaporator 6 reach. The normal refrigerator 3 is therefore only very weakly cooled in the selective cooling operating mode, so that its previously lowered temperature in the super cooling operation mode during the selective cooling operation mode on no account decreases further and ideally even increases significantly.

In the simplest case, the compressor is switched on and off 7 purely time-controlled in the selective cooling operating mode, ie the control circuit 11 comprises a timer, in each case after the passage of a time .DELTA.t0 "the compressor 7 turns it on and off after a period Δt1 "again. According to an alternative embodiment, an evaporator temperature sensor 12 with the control circuit 11 connected and on the freezer evaporator 5 near a refrigerant outlet 15 , on the standard refrigerator evaporator 6 near a refrigerant inlet 14 or at an outlet 15 and inlet 14 connecting line may be arranged to prevent the penetration of liquid refrigerant in an operating phase of the compressor 7 to monitor and the compressor 7 switch off again as soon as a cooling down at the location of the evaporator temperature sensor 12 indicates that liquid refrigerant has arrived in its neighborhood. Since the time it takes the refrigerant to the temperature sensor 12 to reach, depending on the incidence of heat in the freezer 2 can vary, the time periods Δt0 "and Δt1" are not always exactly the same length. However, in this second embodiment, the timer of the control circuit 11 is used to the compressor 7 at fixed intervals, a constant total duration Δt0 "+ Δt1" of an operating-phase and non-operating-phase cycle is obtained.

At the in 1 shown refrigeration device, the refrigerant line extends to the evaporator 6 from the inlet 14 first down a direct way to a lower corner of the evaporator plate, where the evaporator temperature sensor 12 is arranged. Such is the evaporator temperature sensor 12 Although straight way quite far from the inlet 14 removed, but still registers very quickly a cooling when liquid refrigerant starts in the evaporator 6 penetrate. Thanks to the mounting at the bottom of the evaporator board, the temperature sensor 12 during a defrosting process provide reliable information about the amount of food left over during defrosting at the bottom of the evaporator 6 collects.

Since in the selective cooling phase of the evaporator 5 practically constantly contains liquid refrigerant while in the evaporator 6 At best, it can reach the freezer 2 be effectively cooled further, without frost in the normal refrigeration compartment 3 is to be feared.

Again referring to 2 ends the flow D at time t3. As you can see, these are the switch-on times of the compressor 7 during the selective cooling operation mode in the time interval [t2, t3] is calculated so that a non-operation phase of the compressor ends exactly at time t3. Simultaneously with the return to the super cooling mode, the control circuit switches 11 at time t3 the compressor 7 one. Thus, if, as planned by the user when activating the super-cooling mode at time t1, new refrigerated goods are promptly loaded at time t3, then this is due to the simultaneous activation of the compressor 7 immediately cooled down. Since during the previous selective cooling operation phase, the normal refrigeration compartment 3 could heat up significantly above the switch-on of the super-cooling mode, the following at the time t3 compressor operating phase as the following at the time t1 particularly long, so that the newly invited refrigerated goods in a very short time a large amount of heat can be withdrawn.

3 shows a flowchart of a working method of the control circuit 11 , At the beginning of the process is the control circuit 11 in the normal cooling mode: in step S1, it is checked whether the temperature Tnk of the temperature sensor 13 is above the set by the user switch-on threshold Tein, if so, in step S2, the compressor 7 switched on. If not, it is checked in step S3 whether the temperature Tnk is below the turn-off threshold Toff, if so, the compressor is turned off in step S4. Step S5 checks whether a user input, in particular an operation of the operation mode selection switch 17 , is present. If this is not the case, the method returns to the output. Thus, steps S1 to S5 are repeated in an endless loop as long as the normal cooling mode continues.

If it is detected in step S5 that the operation mode selection switch 17 has been actuated, the control circuit sets a timer in step S6 and enters the super-cooling operation mode. In S7, the temperature Tnk is compared with the low switch-on threshold Tein 'specified by the manufacturer and, if this switch-on threshold is exceeded, the compressor is switched on in S8. In step S9, it is checked whether a predetermined low switch-off threshold Taus' is exceeded, if so, in step S10 the compressor 7 switched off again. In step S11 it is checked whether a predetermined dwell time D - n (Δt0 "+ Δt1") - Δt0 "has elapsed since the start S6 of the timer, where n is a natural number and n (Δt0" + Δt1 ") several hours and should be about half of D. If this dwell time has not yet elapsed, the process returns to step S6.

Otherwise, the compressor will 7 (if it is not already off at the time of the check S11) is turned off in step S12, the lapse of a non-operation time Δt0 "is awaited (S13), the compressor is turned on in step S14, and the lapse of the operation time Δt1" is awaited (S15) , The steps S12 to S15 are repeated cyclically until it is determined in step S17 that the predetermined flow D has elapsed since the start of the timer in step S6. Due to the above definition of the dwell time, the end of the flow D always coincides with the end of a non-operation phase.

If the flow D has expired, the process returns to step S7 to chilled goods, which is assumed to be in the freezer at exactly this time 2 has been charged to freeze quickly.

If, since the start of the timer, a time which is likely to be sufficient for freezing the chilled goods, e.g. 48 hours, then this is detected in step S16 and causes the process to return to step S1 and thus to the normal cooling operation mode.

According to one variant, it can be provided that after the lapse of the flow D in step S17 is not jumped back to step S7 unconditionally, but that a time window is opened, whose duration is preferably not greater than .DELTA.t0 "+ .DELTA.t1", and that in this time window control circuit 11 a signal from a switch 16 waits, indicating an operation of a door of the refrigerator, which is to access the freezer 2 must be opened. When this signal arrives, it can be concluded that in fact new refrigerated goods have been stored, and the control circuit 11 responds by jumping to step S7. Thus, the start of the compressor and the invitation of the item to be chilled are exactly synchronized. The window of time passes without the switch 16 indicates a door operation, then the method also returns to step S7 to keep the compartments of the refrigerator cold in the event that, although later than intended, still new goods to be refrigerated is invited.

LIST OF REFERENCE NUMBERS

1

 casing

2

 freezer

3

 Normal refrigeration compartment

4

 wall

5

 Evaporator

6

 Evaporator

7

 compressor

8th

 condenser

9

 dryer

10

 capillary

11

 control circuit

12

 Compressor temperature sensor

13

 temperature sensor

14

 inlet port

15

 outlet

16

 switch

17

 selector

Claims (13)

Refrigerating appliance, in particular household refrigerating appliance, with at least one first storage compartment ( 2 ), which by a with a compressor ( 7 ) connected in a refrigerant circuit first evaporator ( 5 ), a first temperature sensor ( 13 ) and one with the first temperature sensor ( 13 ) connected control unit ( 11 ), which is set up, in a first operating mode, the compressor ( 7 ) when the first temperature sensor ( 13 ) (Tnk) rises above a switch-on temperature, characterized in that the control unit ( 11 ) is switchable to a second operating mode in which the compressor ( 7 ) always turns on when a predetermined cycle time (Δt0 "+ Δt1") has elapsed since a previous switch-on. Refrigerating appliance according to claim 1, characterized in that the control unit ( 11 ) is set after a predetermined dwell time (D - n (Δt0 "+ Δt1 ") - Δt0") in the second operating mode to return to the first operating mode. Refrigerating appliance according to claim 2, characterized in that the time interval between the times at which the control unit ( 11 ) during the second operating mode the compressor ( 7 ), and the end of the dwell time is an integer multiple of the cycle time (Δt0 "+ Δt1"). Refrigerating appliance according to claim 2 or 3, characterized in that the control unit (! 1) is set up, at the end of the residence time the compressor ( 7 ). Refrigerating appliance according to claim 2 or 3, characterized in that it comprises a door and a door sensor ( 16 ) for detecting an actuation of the door and the control unit ( 11 ) is set up during a time window at the end of the residence time the compressor ( 7 ) when the door sensor ( 16 ) detects an actuation of the door. Refrigerating appliance according to one of the preceding claims, characterized in that it by a second evaporator ( 6 ) cooled second storage compartment ( 3 ), that the second evaporator ( 6 ) the first evaporator ( 5 ) is connected downstream in the refrigerant circuit, and the control unit ( 11 ) is set up, in the second operating mode the compressor ( 7 ) again before the amount of liquid refrigerant produced since the last activation for filling both evaporators ( 5 . 6 ) is sufficient. Refrigerating appliance according to claim 6, characterized in that the control unit ( 11 ), the compressor ( 7 ) when the amount of liquid refrigerant produced since last switching on is at least half and at most 1.5 times the capacity of the first evaporator ( 5 ) corresponds. Refrigerating appliance according to claim 6 or 7, characterized in that the control unit ( 11 ), the compressor ( 7 ) to turn off again when a given operating time (Δt1 ") has elapsed since the last power-up. Refrigerating appliance according to claim 6 or 7, characterized in that a second temperature sensor ( 12 ) in a downstream region of the first evaporator, an upstream region of the second evaporator ( 6 ) or a connecting the evaporator refrigerant line is arranged and the control unit ( 11 ) is set up, in the second operating mode the compressor ( 7 ) again when the second temperature sensor ( 12 ) detected temperature the arrival of liquid refrigerant at the temperature sensor ( 12 ). Refrigerating appliance according to one of claims 6 to 9, characterized in that the duration (Δt0 ") of a non-operating time of the compressor ( 7 ) in the second operating mode is long enough to reduce the pressure difference between condenser ( 9 ) and evaporators ( 5 . 6 ) so far that start-up of the compressor ( 7 ) is possible. Refrigerating appliance according to one of claims 6 to 10, characterized in that the duration (Δt0 ") of a non-operating time of the compressor ( 7 ) in the second operating mode is long enough to freeze the second storage compartment ( 3 ) to avoid. Refrigerating appliance according to one of claims 6 to 11, characterized in that the first temperature sensor ( 13 ) at the second storage compartment ( 3 ) is arranged. Refrigerating appliance according to one of the preceding claims, characterized in that the first operating mode is a super-cooling mode in which the switch-on threshold (Tein ') is lower than a set by a user for normal cooling operation set temperature of the second storage compartment ( 3 ).

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