EP2769156A2

EP2769156A2 - Refrigeration appliance comprising an evaporation tray and a heating device for promoting evaporation

Info

Publication number: EP2769156A2
Application number: EP12780140.5A
Authority: EP
Inventors: Roland Bender; Adolf Feinauer; Wolfgang FLICKINGER; Hans Ihle; Peter LIENHART; Achim Paulduro
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2011-10-18
Filing date: 2012-10-11
Publication date: 2014-08-27
Anticipated expiration: 2032-10-11
Also published as: CN103890509A; DE102011084717A1; CN103890509B; WO2013057040A2; EP2769156B1; WO2013057040A3

Abstract

A refrigeration appliance, especially a domestic refrigeration appliance, comprises at least one storage chamber (3), a heat source (10), an evaporation arrangement (9) for evaporating condensed water carried off from the storage chamber (3), a temperature sensor (15) arranged on the evaporation arrangement (9) in thermal contact with the heat source (10), a control unit (13) connected to the temperature sensor (15) and a heating device (10) which can be operated by the control unit (13) to increase the evaporation rate in the evaporation tray (9). The control unit (13) is designed to decide, based on a change in the temperatures detected by the temperature sensor (15), whether operation of the heating device (10) is carried on or discontinued. The evaporation arrangement (9) comprises a main zone (16) and a flooding zone (18) in which the temperature sensor (15) is arranged. The flooding zone (18) contains water in contact with the temperature sensor (15) only if the water level in the main zone (18) has reached or exceeded an overflow level.

Description

Refrigerating appliance with evaporation tray and heating device for

evaporation promotion

The present invention relates to a refrigeration appliance, in particular a household refrigeration appliance such as a refrigerator or freezer, with an evaporation tray for the evaporation of condensate discharged from a storage chamber of the device and a

Heating device that is operable to promote, if necessary, the evaporation of the condensation water in the evaporation tray. The condensation, which is reflected in the storage chamber, gets there as

Part of the stored therein refrigerated goods and in the form of water vapor, which penetrates in each time the door of the refrigerator in the storage chamber

Ambient air is included. The extent of water entry into the storage chamber, and thus the rate at which it flows out of the storage chamber of the evaporation tray, is difficult to estimate because of numerous factors such as the type of product and its packaging, temperature and percentage humidity of the ambient air and the amount the air exchanged at a door opening between environment and storage chamber depends air, and various of these sizes are barely measurable with reasonable effort. The construction of the refrigeration unit must ensure that the condensate in the evaporation tray evaporates quickly enough to reliably prevent overflow, which could damage the refrigeration unit and its surroundings.

Conventionally, such an evaporation tray is usually mounted on a compressor of the refrigerator, with its waste heat the condensation in the

To heat evaporation tray and promote its evaporation. Improvements in insulation and cooling, however, in modern refrigerators result in the ratio of accumulating condensate to the waste heat available at the compressor becoming increasingly unfavorable. Nevertheless, on the evaporation tray on a

to maintain sufficient evaporation temperature was kept

proposed to use an electric heater for heating the condensed water. However, the power consumption of such affects Heating device massively the overall energy efficiency of the refrigerator. Their use is therefore limited to times when this is to prevent the overflow of the

Evaporation bowl is essential. In order to control the heater suitable, it is therefore necessary to monitor the water level in the evaporation tray.

From JP 2009-085473 A, a refrigerator has become known in which a at the

Evaporating tray arranged temperature sensor is used to gain information about the water level. If, during defrosting of this conventional refrigeration appliance, condensate enters the evaporation tray in large quantities, a heating device is activated in order to evaporate the resulting water, and the resulting

Warming is monitored. The more water in the shell, the slower the warming.

A disadvantage of this known refrigeration device is that the accuracy with which the heating rate can infer the amount of water in the evaporation tray is the worse, the fuller it is. That just when the need to accurately estimate the water level is greatest, the accuracy of the estimate is worst. Object of the present invention is therefore to provide a refrigeration device that allows a reliable assessment of the residual capacity of an evaporation arrangement even at high water levels.

The problem is solved by a refrigeration device, in particular a

Domestic refrigeration appliance, comprising at least one storage chamber, a heat source, an evaporation arrangement for evaporating condensate discharged from the storage chamber, a temperature sensor arranged in thermal contact with the heat source at the evaporation arrangement, a control unit connected to the temperature sensor and a heating device which can be operated by the control unit In order to increase the evaporation rate of the evaporation arrangement and which is arranged to decide on the basis of a change in the temperature detected by the temperature sensor via operation or non-operation of the heating device, the evaporation arrangement comprises a main zone and a flooding zone Temperature sensor is disposed in the flooding zone and the flooding zone contains water in contact with the temperature sensor only if the water level in the main zone has reached or exceeded an overflow level.

As long as the overflow level is not reached, the overflow zone is dry, and the

Heating of the temperature sensor by heat emitted by the heat source is independent of the water level in the main zone. Only when the water in the

Flooding zone penetrates, the rate of change of the changes

Temperature sensor detected temperature inversely proportional to the amount of water in the flooding zone. By appropriately setting the overflow level, therefore, a water level just below an upper edge of the evaporation arrangement can be securely detected, regardless of the amount of water contained in the main zone. Since the amount of water in the flooding zone is only a small part of the total content of the evaporation arrangement, a low heat output of the heat source and / or a short measuring time suffice to detect a temperature change which allows a reliable inference to the amount of water.

As a heat source can serve the same heater, which is also used after estimating the amount of water to heat the water. But there are also other heat sources into consideration, especially the

Waste heat from a compressor can be used to generate the resulting heat

To detect temperature change.

According to one embodiment of the invention, the main zone has an overflow edge at the level of the overflow level through which water, when it reaches overflow level, can drain into the flooding zone located below the main zone. Thus, the main zone and the flood zone can form two separate bodies of water at different levels. In this way, since the free water surfaces of the main and the flooding zones can overlap one another in plan view, it is possible to accommodate a large free water surface at which evaporation can take place in a small space. However, if the water body of the flooding zone is at a lower level than that of the main zone, then water from the flooding zone can not enter the

If the water level drops below the overflow level due to evaporation, the main zone will flow back. Therefore, it can not be fundamentally ruled out that the flooding zone will still contain water in contact with the temperature sensor when the water level in the main zone has dropped below the overflow level and therefore heating of the water may not be necessary to prevent overflowing. This disadvantage can be avoided if the

Main zone and the flood zone have a contiguous water level when the water level is above the overflow level.

Preferably, the flooding zone as a whole is above the overflow level, in particular a bottom of the flooding zone should be flat or sloping towards the main zone to allow complete emptying of the flooding zone when the water level in the main zone falls below the overflow level.

In the latter case, it may be appropriate that the main zone and the

Flooding zone are separated by a barrier that does not prevent the exchange of water between them, but hinders to a falsification of the

To avoid temperature measurement by draining warm water from the flooding zone.

This measure is particularly useful if the heater comprises a arranged in the overflow zone heating element. Thus, the barrier from the heater can prevent heated water from draining into the main zone, so that, given the heater power, a rapid temperature rise is achieved.

A arranged in the main zone second heating element, especially in the embodiment with two separate water bodies at different levels, serve to heat if necessary, the water of the main zone quickly and thus to promote its evaporation.

The second heating element may be omitted if there is another heat source, such as the compressor, which can supply enough heat to the main zone. One preferred embodiment of the invention for its simplicity, the temperature sensor is identical to the heating element. Such a temperature sensor may in particular be based on the evaluation of the temperature-dependent ohmic resistance of the heating element.

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 are also 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 must be assumed that, of several such characteristics, it is also possible to omit or modify individual ones, provided that this is the case

Functionality of the invention is not in question. Show it:

Fig. 1 is a schematic section in the width direction by a

Household refrigerating appliance according to a first embodiment of the present invention;

Fig. 2 is a schematic plan view of the evaporation arrangement of

Household refrigerating appliance of Fig. 1; 3 is a diagram in which exemplary developments of the

Temperature sensor of the household refrigerator of Figure 1 measured temperature are plotted at different water levels.

Fig. 4 is a graph illustrating the relationship between rate of rise of temperature and water level in the embodiment of Fig. 1; 5 shows a schematic cross section through an evaporation arrangement according to a second embodiment of the invention;

Fig. 6 is a schematic cross section through an evaporation arrangement

according to a third embodiment of the invention;

Fig. 7 is a graph illustrating the relationship between rate of rise of temperature and water level in the embodiment of Fig. 1;

Fig. 8 is a schematic cross section through an evaporation arrangement

according to a fourth embodiment of the invention;

9 is a schematic plan view of the evaporation arrangement according to the fourth embodiment;

10 is a cross-section similar to FIG. 2 through a refrigerator according to a fifth embodiment of the invention; FIG. and

1 1 shows a cross section through an evaporation arrangement according to a

sixth embodiment of the invention.

The household refrigerating appliance shown in Fig. 1, here a refrigerator, has in the usual way a heat-insulating housing with a body 1 and a lying outside the cutting plane of the figure door, which together define a storage chamber 3. The storage chamber 3 is here cooled by a arranged on its rear wall between an inner container of the body 1 and a surrounding insulating foam layer Coldwall evaporator 4, but should be immediately apparent to the skilled person that explained in the following peculiarities of the invention also in connection with any other types of evaporator, in particular a Nofrost evaporator, are applicable. Also conceivable is the application to a Nofrost freezer, since this, at least in a defrosting phase of the evaporator, also discharges condensation. In the case of the Coldwall refrigerator considered here, a collecting channel 7 extends at the foot of the rear wall of the storage chamber 3 cooled by the evaporator 4

Condensation, located at the cooled by the evaporator 4 area of

The inner container precipitates and flows downhill traps. A pipeline 8 leads from the lowest point of the gutter 7 through the insulating foam layer to an evaporation assembly 9, which is mounted in a machine room 5 on a housing of a compressor 6 to be heated by waste heat of the compressor 6. In a Nofrost refrigeration appliance, a corresponding pipeline could emanate from the bottom of a chamber receiving the evaporator. The evaporation arrangement 9, which is additionally shown in plan view in FIG. 2, comprises a circular shell 16 arranged in direct, close contact with the housing of the compressor 6, the deepest point 17 of which extends annularly around the housing of the compressor 5. From an upper side wall portion of the shell 16 is from a shallow shell 18, whose here substantially horizontal bottom 19 is significantly higher than the lowest point 17 of the shell 16. As long as the water does not rise above the bottom 19, the shell 18 is dry. The shell 16 therefore forms a main zone of

Evaporation 9, which almost constantly contains water, while the shell 18 forms a filled only at high water flooding zone. Since the bottom 19 has no local deepest point separate from the shell 16, the water from the shell 18 flows completely into the deeper shell 16 when the water level in the

Evaporation arrangement drops below the level of the bottom 19.

An electrically operated heating element 10 of the flat shell 18, e.g. a glued on the bottom 19 film heater, therefore falls dry when the water level drops below the height of the bottom 19. The heating element 10 serves on the one hand to monitor the water level in the evaporation arrangement 9 and on the other hand, if necessary, to accelerate the evaporation.

The heating element 10 is controlled by an electronic control unit 13, which is shown here for the sake of simplicity in the engine room 5, but in practice largely arbitrarily on the refrigerator and in particular adjacent to a - can be arranged - not shown here - control panel. The control unit 13 is connected to a temperature sensor 15 which is adjacent to the shell 18 to the heating element 10th is mounted and with thermal water in the shell 18, if any, in thermal contact. In Fig. 1, the heating element 10 and the temperature sensor 15 are shown as separate components; However, it is also conceivable and expedient to simultaneously use a heating element 10 with temperature-dependent ohmic resistance as a temperature sensor 15.

As long as the water level in the evaporation assembly 9 is below the bottom 19, the heating element 10 does not come into contact with the water and the temperature detected by the sensor 15 when the control unit 13 starts to operate the heating element 10 increases extremely rapidly in a short time as indicated by the curve A in Fig. 3.

As long as only the shell 16 contains water, the course of the curve A is independent of the actual water level. If, however, the water level is so high that the water penetrates into the shallow dish 18, then the heating element 10 is flushed over, and the higher the temperature of the water in the dish 18, the slower the temperature increase. as shown by curve C of Fig. 3. Therefore, a limit change rate of the temperature, e.g. 3, it is determined that when the measured rate of change of the temperature is above the limit change rate, the control unit 13 judges that there is no risk of overflow, and after measuring the rate of increase, turns off the heating element 10 again, whereas, if the rate of increase is below the threshold, an overflow hazard is detected and the heater 10 remains in operation for a long time at high power to significantly reduce the level of water in the evaporator assembly 9.

It is easy to understand that for a given heating power of the heating element 10, the sensor 15 registers a faster increase in temperature, if the same time

Compressor 6 is in operation. So that this does not lead to errors in the assessment of the

Water level leads, it can be provided that the control unit 13 operates the heating element 10 only for measuring the rate of increase of the temperature, if not at the same time appreciably heat from the compressor 6 flows to the evaporation tray, i. while the compressor is running and in a given period thereafter, no measurement of the slew rate takes place.

If the refrigeration device is a NoFrost device, condensate enters the evaporation tray 9 every time the evaporator is defrosted. This causes the temperature to rise the water in the evaporation tray 9 clearly below that of the surrounding

Engine room 5 drop off, and heating of the water takes place without action of the heater 10 by temperature compensation with the surrounding engine room. Also this temperature compensation can falsify a measurement of the water level. Therefore, in a NoFrost refrigerator, the control unit 13 is set up, a water level measurement, which is pending at a time at which due to a current or recent defrosting temperature changes in the

Evaporation tray 9 are expected to suspend until these temperature changes have subsided again. Since a power failure depending on its duration can lead to the defrosting of the evaporator, but does not have to, there is a risk that the water level in the evaporation tray 9 after a power failure is significantly higher than before. To possibly one too high

According to another development, the control unit 13 has means for detecting a past one

Power failure and is set up, if a power failure has been detected, immediately perform a measurement of the water level.

4 shows by way of example a typical relationship between the rate of increase dT / dT of the temperature T detected by the sensor 15 and the water level h. As long as the water level h is below the bottom 19, the curve is horizontally at a high level, corresponding to the section a of Fig. At a water level h above the bottom 19, it is inversely proportional to the amount of water in the flat shell 18, i. it has a hyperbolic shape, as shown in section b. The

Dependence of the rate of change on the water level h is greatest when the

Amount of water in the flat shell 18 is small but not zero. Heating element 10 and temperature sensor 15 are therefore expediently mounted just below that level that the water level may not exceed without overflow.

Fig. 5 shows a second embodiment of the evaporation arrangement 9 in cross section. The shells 16, 18 have the same shape as in the case of Figs. 1 and 2, and also arranged in the flat shell 18 heating element 10 is the same. 5, a second heating element 20 in the shell 16 is added. While the rate of rise of the temperature at the sensor 15 is measured, the control unit 13 operates only that Heating element 10, to provide information about the water level at the lowest possible

Gain energy. If the result of the measurement is that there is an overflow hazard, then both heating elements 10, 20 are operated for a while, in order to heat the entire water contained in the evaporation arrangement 9 in a short time and to achieve rapid evaporation.

FIG. 6 shows, in a section analogous to FIG. 5, an evaporation arrangement 9 according to a third embodiment of the invention. Again, a shell 16 is mounted directly on the (not shown) compressor 6. Between her and an adjacent shell 21, a continuous barrier 22 is formed, the upper edge of the

Overflow level defined, beyond which the shell 21 is flooded. The

Heating element 10 is mounted in the shell 21 just above the barrier 22. If the shell 16 overflows, this has so long as no effect on the heating rate of the heating element 20 and its associated sensor 15, as the water level does not reach the heating element 10. As soon as this happens, the rate of increase in temperature decreases. At this time, since the water level in the shell 21 is clearly different from zero, the rate of increase jumps abruptly, as shown in Fig. 7 by a dashed vertical section c between the curve sections a and b. By changing the threshold of the slew rate into the hop interval, e.g. is set to the value T-i of Fig. 7, it can be detected with high accuracy whether the heating element 10 is immersed in the water or not.

In itself, it is desirable to be able to decide not only on the rate of temperature change, whether the water level reaches the installation height of the heating element 10, but whether he exceeds them by a predetermined, nonzero measure or not, because then in case of exceeding the Heating element 10 can efficiently heat the water as long as it is in contact with it, and thus can reduce the water level by just this predetermined level. Such

Decision is not possible with the evaporation arrangement of Fig. 6 with the same accuracy as with that of Figs. 1 and 2, since the slope of the curve of Fig. 7 at the same water level is smaller than that of the curve of Fig. 4. Nevertheless the arrangement of Fig. 6 be advantageous, since the shell 21 also here for

Evaporation can contribute if the water in it does not reach the heating element 10. FIGS. 8 and 9 each show, in section along the plane VIII-VIII of FIG. 9 and in plan view, an evaporation arrangement 9 according to a fourth embodiment of the invention. The shells 16, 18 are in turn substantially the same shape as in the first embodiment, but between them a barrier 23 in height of the shells 16, 18 surrounding walls is formed, which must not be rinsed by the water during operation. Only over a gap 24 of the barrier, an exchange of water between the shells 16, 18 is possible. Thus, by not communicating the shells 16, 18 over their entire width, the outflow of water heated to the heating element 10 into the shell 16 is restricted so that the water in the shell 18 heats up faster than in the case of the first embodiment. Therefore, an accurate

Assessment of the water level is still possible even if the water level is significantly above the heating element 10.

FIG. 10 shows, in a section analogous to FIG. 1, a refrigeration device according to a fifth embodiment of the invention. The evaporation arrangement 9 here comprises two shells 16, 25, which are arranged at different levels. The shell 16 mounted on the compressor 6 includes an overflow edge 26 through which water, when rising above the overflow level, drains into the underlying shell 25. In this shell 25, a heating element 10 and a temperature sensor 15 are arranged, of the

Control unit 13 can be used in the same manner as described with respect to the first embodiment to assess the water level in the shell 25 and to evaporate the water in the shell 25, if the water level is judged therein as dangerous high. Although in this embodiment, the heating of the shell 25 does not promote the evaporation in the shell 16, since, unlike the previously considered

Configurations, a reflux of heated to the heating element 10 water in the shell 16 is not possible, but this can be readily accepted, since the

Possibility to accommodate in a limited volume much free water surface, can take place at the evaporation, at least compensates for this disadvantage and the shell 16 is heated by the compressor 5, on which it is mounted. An evaporation arrangement 9 according to a sixth embodiment of the invention is shown in FIG. 11. On the housing of a compressor 6, a shell 16 is mounted in a conventional manner. From the bottom of the shell 16 is a hollow column 27 from. An annular, at least one slot 29 projects around the upper side 28 of the column openwork bridge 30 on. The top 28 and the bridge limit one

Flooding zone 31. A metal pin 32 extends inside the column from

Compressor housing to the top 28 and dissipates heat of the compressor preferably the flood zone 31, so that when the compressor 6 is running, the temperature in the flooding zone 31 rises much faster than in the surrounding shell 16, and is registered by a temperature sensor 10 arranged there , If the

As the rate of temperature rise falls below a threshold, it can be inferred that there is water in the flooding zone. In this case, a heating device arranged in the shell 16, in this case a heating rod 32 bent into a ring, is switched on and operated for a predetermined time in order to lower the water level below the height of the top side 28.

Claims

Refrigerating appliance, in particular household refrigerating appliance, with at least one storage chamber (3), a heat source (5, 10), an evaporation arrangement (9) for evaporating condensate discharged from the storage chamber (3), one at the

Evaporating arrangement (9) in thermal contact with the heat source (5; 10) arranged temperature sensor (15), connected to the temperature sensor (15) control unit (13) and a heater (10; 32), by the control unit (13) operable is the evaporation rate of the

Evaporation arrangement (9) to increase, wherein the control unit (13) is arranged, based on a change of the detected by the temperature sensor (15)

Temperatures on operation or non-operation of the heating device (10; 32) to decide, characterized in that the evaporation arrangement (9) comprises a main zone (16) and a flooding zone (18; 21; 25; 31) that the temperature sensor (15) in and that the flooding zone (18; 21; 25; 31) contains water in contact with the temperature sensor (15) only when the water level in the main zone (18) is at an overflow level has reached or exceeded.

Refrigerating appliance according to claim 1, characterized in that the heat source is the heating device (10).

Refrigerating appliance according to claim 1, characterized in that the heat source is a compressor (6).

Refrigerating appliance according to one of the preceding claims, characterized in that the main zone (16) has an overflow edge in the amount of the overflow level and the flooding zone (25) is arranged below the main zone (16).

Refrigerating appliance according to one of claims 1 to 3, characterized in that the main zone (16) and the flooding zone (18; 21; 31) have a

contiguous water level when the water level is above the overflow level.

6. Refrigerating appliance according to claim 5, characterized in that the flooding zone (18; 31) is arranged above the overflow level.

7. Refrigerating appliance according to claim 5 or 6, characterized in that a bottom (19) of the flooding zone (18) is flat or down to the main zone (16) down.

8. Refrigerating appliance according to one of claims 5 to 7, characterized in that the main zone (16) and the flooding zone (18; 31) by a barrier (22; 23; 30) are separated, which impedes the exchange of water between them.

9. Refrigerating appliance according to one of the preceding claims, characterized in that the heating device (10) comprises at least one in the overflow zone (18; 21; 25) arranged heating element (10).

10. Refrigerating appliance according to one of the preceding claims, characterized in that the heating device in the main zone (16) arranged heating element (32).

1 1. Refrigerating appliance according to claim 9, characterized in that the main zone (16) has no heating element.

12. Refrigerating appliance according to one of the preceding claims, characterized in that at least the main zone (16) on a compressor (6) is mounted.

13. Refrigerating appliance according to one of the preceding claims, characterized in that the temperature sensor is identical to the heating element.

14. Refrigerating appliance according to one of the preceding claims, characterized in that the control unit is set up to perform a Messbetriebsphase not with the compressor running (6).

15. Refrigerating appliance according to one of the preceding claims, characterized in that the control unit is set up to perform a Messbetriebsphase not during a defrosting operation.

16. Refrigerating appliance according to one of the preceding claims, characterized in that the control unit is set up to carry out a measuring operation phase in each case after a power failure.