EP3542110A1

EP3542110A1 - Refrigerator having a storage compartment with optimised air humidity

Info

Publication number: EP3542110A1
Application number: EP17797614.9A
Authority: EP
Inventors: Niels Liengaard; Matthias Mrzyglod
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2016-11-21
Filing date: 2017-11-08
Publication date: 2019-09-25
Also published as: WO2018091323A1; US20200064048A1; CN109983288A; DE102016222948A1

Abstract

The invention relates to a refrigerator comprising a coolant circuit in which a speed-controlled compressor (5), an adjustable throttle point (12) and a force-ventilated first evaporator (11, 13) are connected in series, an evaporator chamber (14, 15) which receives said first evaporator (11, 13), a first storage compartment (1, 3) that communicates with the evaporator chamber (14, 15), a second storage compartment (2, 24) that communicates with said evaporator chamber (14, 15), and a control unit (23) configured to distribute cold air from the evaporator (11) to the first and the second storage compartments (1, 3; 2, 24) in accordance with target temperatures that can be set individually for said first and second storage compartments (1, 3; 2, 24).

Description

Refrigeration unit with humidity-optimized storage compartment

The present invention relates to a refrigerator with a storage compartment whose humidity is optimized for a particular type of stored goods. The humidity that prevails in a storage compartment of a refrigeration device has an influence on the achievable storage time. While high levels of humidity are desirable, especially for the storage of leafy or root vegetables, to limit evaporation, for fruits that have a naturally evaporative-limiting shell, as well as for packaged chilled goods, dry storage is more beneficial, particularly to prevent mold growth.

Under normal operating conditions, the evaporator of a refrigerator is always colder than a storage compartment cooled by the evaporator. If the temperature difference is high enough to cool air from the storage compartment into contact with the evaporator below the dew point, condensation will settle on the evaporator. In conventional refrigerators with intermittently operated compressor is reliably at least during the operating times of the compressor, so that the relative humidity in a storage compartment of such a device does not reach high levels. In order to maintain a high level of humidity in an energy-efficient manner, the temperature difference between evaporator and storage compartment must be minimized. This is achieved by, on the one hand, a variable-speed compressor is continuously operated with the exact power required to maintain a desired temperature in the storage compartment and the passage cross-section of an adjustable throttle is adjusted so that the pressure in the evaporator, the vapor pressure of the refrigerant in maintaining the target temperature of the storage compartment required evaporator temperature corresponds.

In the non-prepublished German patent application 10201521 1960.2 is a refrigerator with a refrigerant circuit in which a variable speed compressor, an adjustable throttle and a forced-ventilated first evaporator are connected in series, a first storage compartment, which accommodates a first evaporator Evaporator communicates, and a second storage compartment, described, in which the evaporation temperature, which sets in one of the evaporators in the flow mode, with the aid of upstream and downstream controllable throttle valves is controlled, and the humidity in the cooled by this evaporator compartment by the temperature difference between the compartment and the evaporator is determined.

The technique described in this earlier application is essentially suitable only for refrigerators of the upper price segment, as high number of controllable throttle valves and evaporators makes the manufacture of the device consuming and expensive.

An object of the present invention is to provide a refrigeration device which allows adjustment of the humidity in a storage compartment with simpler, more cost-effective means. The object is achieved by the second storage compartment communicates with the evaporator chamber in a refrigerator of the above type and a control unit is arranged to distribute cold air from the evaporator according to the first and the second storage compartment differently adjustable target temperatures to the first and the second storage compartment. The invention makes use of the fact that in a forced-air evaporator, the temperature setting in a storage compartment cooled by the evaporator depends not only on the temperature of the evaporation but also on the intensity of the air exchange. Therefore, it is on the one hand possible to keep two storage compartments at different nominal temperatures with a single evaporator by the air exchange of the storage compartments is set to different intensities with the evaporator. When warmer of the two compartments, the difference between compartment and evaporator temperature can be large and the air drying accordingly strong; on the other hand, with the colder compartment, the above-described conditions for high humidity can be well approximated. The distribution of the cold air to the storage compartments may include that each storage compartment is supplied with a specific, non-zero portion of the outgoing from the evaporator chamber cold air flow; but it can also be done by periods in which this cold air flow is completely supplied to the one storage compartment, and periods, in which he is completely fed to the other storage compartment, alternate with each other. The second alternative is the preferred one because it involves less mixing of the storage compartment air.

In order to effectively limit the drying of the second storage compartment, the control unit should be set up to limit a temperature difference between the evaporation temperature in the first evaporator and the setpoint temperature of the second storage compartment to a maximum of 7 ° C. This allows in particular an operation of the first storage compartment as a normal refrigeration compartment, the target temperature is typically in an interval of 5-8 ° C, and the second storage compartment as a cold storage compartment with a set temperature of typically 1 -4 ° C.

Conversely, the control unit can also be set up to maintain a temperature difference between the evaporation temperature in the first evaporator and the setpoint temperature of the second storage compartment of at least 20 ° C., in order to achieve very dry storage conditions in the second compartment. This is particularly possible when the first compartment is tempered as a freezer and the second compartment as a cold storage compartment.

The control unit may be configured to operate the variable speed compressor continuously.

In order to control the distribution of the cooling capacity of the evaporator to the first and the second storage compartment, a flap which can be adjusted by the control unit can be arranged in at least one passage between the evaporator chamber and the storage compartments.

A fan for circulating the cooled air at the evaporator can then supply both compartments together. In order to limit a mixing of air of the two compartments in the evaporator chamber, the flap preferably has two stable positions, in one of these positions the passage between the evaporator chamber and the first storage compartment open and between the evaporator chamber and the second storage compartment is closed, and in the other position, the passage between the evaporator chamber and the first storage compartment is closed and open between the evaporator chamber and the second storage compartment.

Alternatively, two fans may be provided with throughputs controllable by the control unit, one of which is accommodated in one passage between the evaporator chamber and the first storage compartment and the other in one passage between the evaporator chamber and the second storage compartment.

In this case, the fans should not operate simultaneously to minimize the mixing of air from the two storage compartments.

The pressure of evaporation in the first evaporator will generally be higher than the suction pressure of the compressor. To take advantage of this pressure gradient, the refrigerant circuit may comprise a second evaporator, which is connected downstream of the first evaporator via a throttle point.

This second evaporator can cool at least a third storage compartment.

In order to be able to divide the cooling capacity of the second evaporator flexibly according to requirements between the third and a fourth storage compartment, the second evaporator can also be forced ventilated and accommodated in an evaporator chamber separate from the third storage compartment.

A control unit may be provided to control the exchange of air between the evaporator chamber and the third storage compartment and between the evaporator chamber and a fourth storage compartment based on setpoint temperatures of the third and the fourth storage compartment.

Second and fourth storage compartment can be identical. Then one and the same storage compartment can be selectively operated by exposure to cold air from the first evaporator, at high humidity or, h exposure to cold air from the second evaporator, at low humidity. Alternatively it can be provided between the second and fourth storage compartment an adjustable partition, which allows to adapt the sizes of the two storage compartments flexibly to the respective needs.

The object is further achieved by, in a refrigerator with a refrigerant circuit in which a compressor, a throttle point, a forced-ventilated first evaporator and a forced-ventilated second evaporator are connected in series, wherein the second evaporator is connected downstream of the first evaporator via a throttle point in series a first and a second storage compartment and a control unit configured to maintain the first storage compartment at a first set temperature by controlling the air exchange between the first evaporator and the first storage compartment, the control unit is further configured to selectively exchange the second storage compartment by air exchange to keep the first or the second evaporator at a second set temperature so as to be able to set different values of the humidity in the second storage compartment independently of the setpoint temperature.

A third storage compartment can be cooled in this refrigerator by exchanging air with the second evaporator.

Further features and advantages of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. Show it:

Fig. 1-4 are block diagrams of refrigerators according to various embodiments of the invention.

Fig. 1 shows a block diagram of a refrigerator according to a first embodiment of the invention. The refrigeration device is a combination device with a warm, an intermediate and a cold storage compartment 1, 2 or 3, typically a normal refrigeration compartment, a cold storage compartment and a freezer, which are cooled by a compression refrigerator 4. The compression refrigeration machine 4 comprises a speed-controlled compressor 5 and, in sequence, at one of a pressure port 6 of the compressor 5 to the suction port 7 extending Refrigerant line 8, a condenser 9, a first throttle point 10, a first evaporator 1 1, a second throttle point 12 and a second evaporator thirteenth

The evaporators 1 1, 13 are housed in evaporator chambers 14, 15. The evaporator chamber 14 communicates via flow lines 16, 17 and return lines 18, 19 with the normal cooling compartment 1 and the cold storage compartment 2. Both evaporator chambers 14, 15 each include a fan 20, 21 for driving the air exchange between the evaporator chambers 14, 15 and the connected storage compartments. 1 2, 3. FIG. 1 shows a flap 22 at the junction of the feed lines 16, 17 with the evaporator chamber 14; the flap 22 is pivotable between two positions, in which it blocks one of the supply lines 16, 17 and the other releases. Shown is in an intermediate position in which both supply lines 16, 17 are open. Alternatively, the flap could be located at the junction between the return lines 18, 19 and the evaporator chamber 14 to block one of the return lines 18, 19 and release the other. According to other alternatives, two flaps could be distributed on the supply lines 16, 17 or on the return lines 18, 19, or the fan 20 could be replaced by two fans in the supply lines 16, 17 or the return lines 18, 19, which are independent of each other controlled speeds or, preferably, at each different times are operable to control the air exchanges between the evaporator chamber 14 and the compartments 1, 2 each independently.

At each storage compartment 1, 2, 3 a not shown in Fig. 1 for the sake of clarity, temperature sensor is provided. The temperature sensors are connected to an electronic control unit 23. A setpoint temperature can be set for the control unit 23 for each storage compartment 1, 2, 3. Based on the measured values supplied by the temperature sensors and the setpoint temperatures, the control unit 23 controls the speed of the compressor 5, the position of the flap 22 and the opening degree of at least one of the two throttle points 10, 12 or both. If one of the two throttle points is not controllable, then this is preferably the first throttle point 10. In order to cool the normal refrigerated compartment 1 and cold storage compartment 2 at the same time, the cold air flow from the evaporator 1 1 must be distributed to the two compartments. This can be done by the flap 22 is in an intermediate position in which they are completely blocked 16 and 17, none of the flow lines and cold air from the evaporator 1 1 simultaneously to two compartments 1, 2 flows, however, this leads to a mixing of different humid air masses the compartments 1 and 2 in the evaporator chamber 14 and thus ultimately to an outflow of humidity from the cold storage compartment 2. To minimize this, it is preferred to switch the flap 22 at regular intervals between its two stop positions for cooling of the normal refrigerated compartment 1 and cold storage compartment 2 , so that - apart from the times in which the flap moves from one stop position to the other - one of the two supply lines 16 and 17 is always blocked.

Each switching of the flap 22 causes an amount of air corresponding to the volume of the evaporator chamber 14 to be exchanged between the compartments 1 and 2. In order to minimize the effects of this replacement, the time span between two switching of the flap 22 should be greater than the quotient of volume of the evaporator chamber 14 and throughput of the fan 20, preferably greater than ten times this quotient. If the temperature of the cold storage compartment 2 is above the target temperature, but not the normal refrigeration compartment 1, the control unit 23 extends the time that the flap 22 in the supply line obstructing position 16 brings, and correspondingly shortens the in the supply line 17 obstructing position brought Time to increase the air exchange between the evaporator chamber 14 and the cold storage compartment 2. This can be sufficient as a corrective measure if the cooling capacity of the evaporator 1 1 is sufficient for both compartments 1, 2. If it does not do so, sooner or later both compartments 1, 2 will heat up above their set temperature. If this happens, the freezer compartment 3 but does not exceed its target temperature, then the throttle bodies 10, 12 or at least the throttle point 12 are driven to reduce the pressure difference between the evaporators 1 1, 13 and so to reduce the evaporation temperature in the evaporator 1 1. If this leads to an exceeding of the setpoint temperature in the freezer compartment 3, then the speed of the compressor 5 must be increased. In this way, a temperature sets on the evaporator 1 1 over time, which is just far enough below that of the cold storage compartment 2 to keep it at the set temperature. Moisture from the air of the cold storage compartment 2 is reflected on the evaporator 1 1 only when the humidity in the cold storage compartment 2 so high and the temperature difference to the evaporator 1 1 is so great that the air exceeds the dew point on cooling the evaporator 1 1. The saturation amount of water vapor in air decreases by about one third when the temperature decreases by 5 ° C. Only if the relative humidity in the cold storage compartment 2 exceeds 67%, can therefore lead to a cooling by 5 ° C at the evaporator 1 1 to condensation, and a relative humidity of 67% can not be exceeded.

The temperature difference between the normal cooling compartment 1 and the evaporator 1 1 is much larger; Accordingly, the air of the normal cooling compartment 1 is dried by the evaporator 1 1 much more. The user can take this into account by using the cold storage compartment 2 for refrigerated goods sensitive to desiccation, whereas the normal refrigerated compartment 1 uses refrigerated goods that are insensitive or packaged against dry storage conditions.

The evaporator 13 cools in the embodiment of Fig. 1 only the freezer compartment. 3

In the embodiment of FIG. 2, a drying compartment 24 is additionally provided. Its setpoint temperature can be set at a similar height as that of the cold storage compartment 2. The evaporator chamber 15 communicates with the freezer compartment 3 and the drying compartment 24 via supply and return lines 25, 26, 27, 28 in the same manner as the evaporator chamber 14 with the normal refrigeration compartment 1 and the cold storage compartment 2. FIG. 2 each shows a flap 22 at the junction of the feed lines 16, 17 with the evaporator chamber 14 and the feed lines 25, 26 with the evaporator chamber 15. These flaps 22 are each replaced by the same alternatives as described with reference to FIG.

The temperature difference between the setpoint temperature of the drying compartment 24 and the evaporator 13 is even greater than that between the setpoint temperature of the normal cooling compartment 1 and the evaporator 1 1; Accordingly, the air is dry from the Evaporator chamber 15 flows back to the drying compartment 24. At a temperature difference between drying compartment 24 and evaporator 13 of 20 ° C, the humidity in the drying compartment can be kept below 25%.

In the embodiment of Fig. 3, the evaporator chamber 15 via the supply and return lines 26, 28 connected to the same cold storage compartment 2 as the evaporator chamber 14. All supply lines 16, 17, 25, 26 are each shut off by a flap 29. 3, the flaps 29 of the supply lines 17, 25 are open and the flow lines 16, 26 are closed, so that the fan 20 drives a flow of air through the cold storage compartment 3, while the normal cooling compartment 1 is cut off from the cold air supply, and the fan 21 supplies the freezer compartment 2 with cold air. Since the temperature of the evaporator 1 1 is only slightly below that of the cold storage compartment 2, the relative humidity in the cold storage compartment 2 can be high. If, instead, the user desires low humidity in the cold storage compartment 2, he may make a corresponding adjustment to the control unit 23 (not shown in FIG. 3 for clarity); this responds by closing the flap 29 of the supply line 17 permanently to separate the cold storage compartment 2 from the evaporator 1 1, and instead switches the flaps 29 of the supply lines 25, 26 periodically to the cold air from the evaporator 13 between the freezer 3 and to divide the cold storage compartment 2. Due to the low temperature of the evaporator 13 so dry air enters the cold storage compartment 2. Furthermore, the control unit 23 narrows the passage cross section of the throttle point 12 to account for the shift of refrigeration demand from the evaporator 14 to the evaporator 15.

As in the case of FIG. 2, there is the cold storage compartment 2, which has the evaporator 14 in common with the normal refrigeration compartment 1, and the drying compartment 24, the evaporator 15th with the freezer 3 has in common. Cold storage compartment 2 and drying compartment 24 are surrounded by a common inner container 30, the boundary between them is formed by a wall 31. The wall 31 can be mounted in various positions in the inner container 30, for example, in the same manner as conventional shelves by placing on support projections 32 on the walls of the inner container 30. So can if necessary by Changing the position of the wall 31 of one of the compartments 2, 24 enlarged and the other be reduced.

The wall 31 can also be removed so that only a single storage compartment remains in the inner container 30. This can then, as described with reference to FIG. 3, optionally be operated as a cold storage compartment with high or low atmospheric humidity.

reference numeral

1 storage compartment (normal refrigerated compartment)

2 storage compartment (cold storage compartment)

3 storage compartment (freezer compartment) 4 compression refrigeration unit

5 compressors

6 pressure connection

7 suction connection

8 refrigerant line

9 liquefier

10 throttle point

1 1 evaporator

12 throttle point

13 evaporators

14 evaporator chamber

15 evaporator chamber

16 flow line

17 supply line

18 return line

19 return line

20 fans

21 fan

22 flap

23 control unit

24 drying compartment

25 flow line

26 supply line

27 return line

28 return line

29 flap

30 inner container

31 wall

32 support projection

Claims

Refrigerating appliance with a refrigerant circuit, in which a speed-controlled compressor (5), an adjustable throttle point (12) and a forced-ventilated first evaporator (1 1, 13) are connected in series, one of the first evaporator (1 1, 13) receiving the evaporator chamber (14 , 15), a first storage compartment (1, 3) which communicates with the evaporator chamber (14, 15), and a second storage compartment (2, 24), characterized in that the second storage compartment (2, 24) with the evaporator chamber ( 14, 15) and a control unit (23) is arranged, cold air from the evaporator (1 1) according to the first and the second storage compartment (1, 3, 2, 24) differently adjustable target temperatures on the first and the second storage compartment (1 , 3, 2, 24).

Refrigerating appliance according to claim 1, characterized in that the control unit (23) is adapted to limit a temperature difference between the evaporation temperature in the first evaporator (1 1) and the set temperature of the second storage compartment (2) to a maximum of 7 ° C.

Refrigerating appliance according to claim 1, characterized in that the control unit (23) is adapted to maintain a temperature difference between the evaporation temperature in the first evaporator (13) and the target temperature of the second storage compartment (22) of at least 20 ° C.

Refrigerating appliance according to one of the preceding claims, characterized in that arranged on at least one passage between the evaporator chamber (14, 15) and the storage compartments (1, 3, 2, 24) by the control unit (23) adjustable flap (22, 29) is.

Refrigerating appliance according to claim 4, characterized in that the flap (22, 29) has two stable positions, wherein in one of these positions, the passage between the evaporator chamber (14, 15) and the first storage compartment (1, 3) open and between the evaporator chamber (14, 15) and the second storage compartment (2, 24) is closed, and in the other position the passage between the

Evaporator chamber (14, 15) and the first storage compartment (1, 3) is closed and between the evaporator chamber (14, 15) and the second storage compartment (2, 24) open. 6. Refrigerating appliance according to claim 4, characterized in that in a passage between the evaporator chamber and the first storage compartment, a first fan and in a passage between the evaporator chamber and the second storage compartment, a second fan is housed and the flow rates of the fan can be controlled by the control unit ,

7. Refrigerating appliance according to claim 6, characterized in that the fans are not simultaneously in operation.

8. Refrigerating appliance according to one of the preceding claims, characterized in that the refrigerant circuit comprises a second evaporator (13), the first

Evaporator (1 1) via a throttle point (12) is connected downstream.

9. Refrigerating appliance according to claim 8, characterized in that the throttle point (12) is the adjustable throttle point and a second throttle point (10) is connected upstream of the first evaporator (1 1).

10. Refrigerating appliance according to claim 8 or 9, characterized in that the second evaporator (13) at least a third storage compartment (3) cools. 1 1. Refrigerating appliance according to claim 10, characterized in that the second evaporator (13) is positively ventilated and housed in a separate from the third storage compartment (3) evaporator chamber (15).

12. Refrigerating appliance according to claim 1 1, characterized in that a control unit (23) is arranged, the exchange of air between the evaporator chamber (15) of the second evaporator (13) and the third storage compartment (3) and between the evaporator chamber (15) and a fourth storage compartment (4) based on target temperatures of the third and the fourth storage compartment to control.

13. Refrigerating appliance according to claim 12, characterized in that the second and the fourth storage compartment (2) are identical.

14. Refrigerating appliance according to claim 12, characterized in that between the second and fourth storage compartment (2, 24) an adjustable partition wall (31) is provided.

15. Refrigerating appliance according to one of the preceding claims, characterized in that the control unit (23) is adapted to operate the speed-controlled compressor (5) continuously.