WO2012076434A2

WO2012076434A2 - Refrigerator with forcibly cooled heat exchanger

Info

Publication number: WO2012076434A2
Application number: PCT/EP2011/071689
Authority: WO
Inventors: Jochen HÄRLEN; Qiwu Zhu; Weizhong Zhu
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2010-12-09
Filing date: 2011-12-05
Publication date: 2012-06-14
Also published as: CN103250017A; DE102010062735A1; WO2012076434A3; EP2649388A2

Abstract

In the case of a refrigerator, in particular a domestic refrigerator, having a heat exchanger and at least one fan for driving an air stream through the heat exchanger, the throughflow direction of the heat exchanger is reversible.

Description

Refrigeration unit with forced-cooled heat exchanger

The present invention relates to a refrigeration appliance, in particular a household refrigerating appliance, with a heat exchanger and at least one fan for driving an air flow through the heat exchanger.

Domestic refrigerators, in which the effectiveness of a heat exchanger is increased by a fan, are well known. Thus, in particular so-called NoFrost devices are characterized by the fact that they have as forcibly ventilated heat exchanger an evaporator, which is housed in a separate chamber from a storage chamber for refrigerated goods and the storage chamber cooled by air exchange. But also condenser can be forced ventilation, especially compact condenser, which are not mounted on a rear wall of the refrigerator housing, but in a

Machine room niche of the housing are housed. The present invention relates primarily to refrigerated appliances with forced air

Condenser, but in principle also applicable to any forced-ventilated heat exchanger.

To be efficient, heat exchangers need a large surface area on a small scale

Accommodate volume. Dust particles that are carried along in the surface sweeping air deposit over time, so that after prolonged use on the heat exchanger forms a dust layer, the

Heat exchange significantly impeded. In order to ensure a good Wrkungsgrad of the refrigerator, this dust layer would have to be removed regularly. However, users of household refrigerators are not accustomed to doing this, and even if they were willing to do so, the heat exchangers in a refrigerator are usually difficult to access, so that manual cleaning, if at all possible, is extremely difficult. Object of the present invention is to provide a refrigeration device that allows for a long time operation with excellent Wrcungsgrad without requiring a user to clean the heat exchanger. The object is achieved in which in a refrigeration device with a heat exchanger and at least one fan for driving an air flow through the heat exchanger, the flow direction of the heat exchanger is reversible.

The effectiveness of the reversal of the flow direction is based on the fact that impurities are preferably located on an upstream side of the

Heat exchanger deposit because they are at macroscopic or microscopic

Surface irregularities get stuck. Although these bumps prevent the contaminants from passing through the heat exchanger, they at best hold it back weakly when the flow direction of the heat exchanger reverses. As a result, by reversing the flow direction, a considerable portion of the impurities deposited on the heat exchanger can be expelled therefrom again, and an efficient heat transfer from the

Heat exchanger on the passing air stream can be maintained permanently.

In order to reverse the flow direction of the heat exchanger, two fans may be provided, which are each arranged to drive air flows in the opposite direction through the heat exchanger. Easier and cheaper is the use of a single fan between a heat exchanger

blowing mode and a suction from the heat exchanger operating mode is switchable.

In order to switch the operating mode, a flap can be provided which allows the heat exchanger in each case to be acted upon in different directions by an air flow driven by the fan. Such a flap and running between her and the heat exchanger lines take up considerable space. The space requirement can be reduced if, for switching between the operating modes, the running direction of a rotor of the fan can be changed. In such a case, the flap is not needed.

It is possible that the refrigeration device both flow directions of the

Heat exchanger uses to the same extent, for example by the

Flow direction at regular intervals or at each standstill of Compressor is reversed. In this case it is to achieve a good one

Cleaning effect expedient, after each reversal of the flow direction to operate the fan initially at high speed to the dirt from

Dissolve heat exchanger, and then, during normal cooling operation, operate it at a lower speed.

An optimization of the flow paths of the air in the refrigerator with respect to e.g. However, low flow resistance and / or low flow noise is easier if it has to be made only for one direction of flow or if the requirements for a rarely used flow direction may be more generous than for a predominantly used one. Therefore, it is preferable that the

Heat exchanger in the cooling mode is flowed through only in a single first direction, and a flow in the second direction takes place only for a short periods of time to clean the heat exchanger. The operating mode in which the fan operates predominantly, during the cooling operation, is preferably aspirating. This has the advantage that the dirt collects during the cooling operation predominantly on the side facing away from the fan fluid side of the evaporator and can be eliminated by blowing again. Therefore, the dirt does not need to be able to be removed effectively to pass the fan.

A channel on which the fan driven air is passed through the refrigerator, may expediently have on a side facing away from the fan side of the heat exchanger, a section in which the speed of a fan-driven air flow is lower than in the heat exchanger itself. In such Section can settle on a cleaning process from the fan solved dirt and remain permanently when the cooling operation is resumed.

If the cleaning of the heat exchanger takes place in the suction mode, such a section with a lower flow speed is expediently provided on a side of the heat exchanger facing away from the fan. Otherwise, such a section with a reduced flow rate is expediently provided on a side of the fan facing away from the heat exchanger.

In one case as in the other case, it is expedient if this section comprises a branching off from a main passage direction of the channel pocket in which the dirt against the air flow in the channel can remain permanently shielded.

It is also advantageous if a wall of the channel carries projections, in particular in the form of hooks, needles or bristles, which are directed against an airflow running along the wall to the heat exchanger. Such projections hardly hinder the transport of coarse flockigem, detached from the heat exchanger dirt from the heat exchanger. However, if after the cleaning process, the direction of the air flow back to the heat exchanger, the projections may hinder the return of dirt to the heat exchanger and possibly deflect it to the wall and bind there.

The inventively provided possibility of reversing the flow direction makes the use of an air filter in the channel makes sense. While in a conventional refrigeration device without reverse flow, the risk that if such a filter is clogged by dirt, the flow through the

Heat exchanger is greatly reduced and the effect of the heat exchanger is even more limited than by a deposited thereon dirt layer can be eliminated by reversing the direction of such a deposit of dirt from the filter, so that the deposition of dirt on the heat exchanger itself can be prevented from the outset.

In order for the air flow driven by the fan to pass completely through the heat exchanger, both are expediently connected by a pipe section.

It is also advantageous if the heat exchanger, the fan and the pipe section are combined to form a unit which is mounted as a unit in the refrigerator. To effectively remove the deposited debris, the throughput of the fan in its operating mode used for cleaning is advantageously higher than that used for normal cooling operation. Any noise development associated with the higher throughput may be tolerated in the short periods of time required for cleaning.

Appropriately, an operating state display can be provided, at which the respective selected flow direction can be seen. If a change in the operating noise is associated with the change in the direction of flow or, as the case may be, the change in the flow rate associated therewith, a user perceiving that change will be able to clarify the cause by means of the operating status display.

Further features and advantages of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. FIG. 1 shows a perspective view of a refrigerator according to the invention from the rear; FIG. 2 is a perspective view of the refrigerator from the front;

Fig. 3 is a longitudinal section of a condenser, a fan and a

Pipe section comprehensive assembly according to a first embodiment; FIG. 4 shows a section analogous to FIG. 2 according to a second embodiment; FIG.

Fig. 5 shows a section through the engine room of a refrigeration device, in which the

Condenser fan assembly of Figure 3 is installed; 6 shows a section through the engine room of a refrigeration device with a

Condenser-fan assembly according to a third embodiment; and 7 is a section through the engine room and the condenser fan

Assembly according to a development of the third embodiment along the plane VII-VII of FIG. 6.

Fig. 1 shows in a perspective view from behind a household refrigerator according to the invention in table construction. At the foot of a rear wall of the body 1 of the refrigerator, a machine room niche 2 is recessed. It extends in

Substantially in the entire width and in about half the depth of the body 1 and includes, inter alia, a compressor 3 and a condenser fan assembly 4. The condenser fan assembly 4 has a substantially cuboid, open on two opposite sides of the housing 5. One of the open sides faces the compressor 3. At this open side, an axial fan 6 is mounted, i. a fan whose rotating paddle wheel drives an airflow parallel to its axis of rotation. Such a fan is preferred in the context of the present invention to be there

Wrkungsgrad, unlike a radial fan, at most slightly depends on its direction. The second open side of the housing 5 is spaced from a side wall of the engine room niche.

When the compressor 3 is in operation to cool a storage chamber 7 (see FIG. 2) inside the body 1, the running direction of the fan 6 is selected such that it simultaneously draws air from the housing 5 and against the compressor 3 blows. This air enters the housing 5 via a gap 8 between the assembly 4 and the side wall of the machine room niche and the open side facing away from the fan 6 and flows through the condenser accommodated therein. The condenser 9 can, as shown in Fig. 3, a finned evaporator with arranged parallel to the flow direction lamellae 10 and a meandering in the slats 10

Be refrigerant tube 11. Alternatively, the condenser 9 could also be designed as a wire tube condenser or pure tube condenser; In general, any design is compact enough to be accommodated in the housing 5. The fan 6 is controlled by an electronic control unit, not shown, such as a microcontroller. Preferably, this control unit is the same, which also in a generally conventional manner, the operation of the compressor 3 based on a in the storage chamber 7 measured temperature controls. In the context of the invention come several

Method according to which the control unit can control the fan 6:

According to a first method, when the control unit detects cooling demand in the storage chamber 7, it also starts the fan 6 at substantially the same time as the compressor 3 so that it sucks air through the condenser 9 and blows against the compressor 3. In this case, dust collects in a region 12 facing away from the fan 6 of the condenser 9. The control unit counts the operating hours spent by the fan 6 in this operating state, and when a limit is reached, the running direction of the fan 6 switches, so that this blowing air through the condenser 6 for a few minutes while blowing out the dust deposited in the area 12 out of the condenser 9 again. In order to enable effective removal of the dust in a short time, the speed of the condenser 9 at this time may be higher than that of the normal cooling operation. The operating hours counter is reset and starts to count again, so that the blowing off of the dust repeats periodically.

The reversal of the blowing direction of the fan 6 and / or the increase in its rotational speed may result in the operating noise of the refrigerating appliance during cleaning of the liquefier 9 being distinctly different from the operating noise in the normal cooling operation. In order to prevent a user suspecting a technical fault here, a field may be provided on an operating status display 14 on the front of the body 1, at the state of which a user can recognize whether or not a cleaning of the liquefier 9 is currently in progress. An alternative to using an operating hours counter is that the control unit allows the fan 6 to be blown against the condenser 9 once for a short time in each operating phase of the compressor 3. Such a blowing may take place, for example, at the beginning of each operating phase of the compressor when it begins to circulate the refrigerant, but the conversion has not yet led to a noticeable heating of the condenser 9.

It is also possible to blow the fan 6 each time following an operating phase of the compressor 3 against the condenser 9, so as in the immediately remove the previous operating phase in the area 12 deposited dirt before it can attach firmly to the condenser 9.

Another possibility of the control of the fan 6, whose direction at regular intervals, in particular for a predetermined number of

Operating hours of the compressor 3, to reverse, or to reverse the direction of the fan 6 each from an operating phase of the compressor 3 to the next. Thus, dirt that has settled during an operating phase in the area 12 of the condenser, in the subsequent operating phase, in reverse

Direction of flow, gradually eliminated, while at the same time dirt on the fan 6 facing side 13 of the condenser 9 can settle. This is in turn eliminated in the next operating phase of the compressor, in which the condenser is again flowed through in the same direction as in the first phase.

Again, it may be appropriate to enhance the cleaning effect by the fan 6 each at the beginning of a switch-on for a short time with increased

Speed is operated.

It is also conceivable that the running direction of the fan 6 is not reversed between two operating phases, but shortly before the end of each individual operating phase, in order to eject the dust deposited in the course of this operating phase. Again, the speed of the fan when blowing the dust can be selected higher than during the previous normal cooling operation.

4 shows a section analogous to FIG. 3 through a condenser-fan assembly 4 according to a second embodiment. This assembly 4 is intended to work together with a control unit operating according to the first method described above, in other words it is intended for an operating mode in which the fan 6 draws air through the condenser 9 during cooling operation and in

Cleaning operation air against the condenser 9 blows. An on the fan

remote from the housing 5 arranged filter 15, which may have the form of a wire mesh or a piece of expanded metal, for example, keeps sucked coarse lint from the condenser 9 away. Thus, in the course of operation, a dirt layer settles on the Filter 15, which, as well as the condenser 9 in the condenser fan assembly 4 of FIG. 3, can be cleaned by blowing again.

Fig. 5 shows a section through the machine room niche 2 of a refrigerator according to a further developed embodiment of the invention. The sectional plane is vertical in the width direction of the body 1. The figure shows a condenser-fan assembly 4 of the type described with reference to Fig. 2; just as well, one of the type of Fig. 3 could be used.

Openings 16 through which fresh air enters the machine room niche 2 are formed in a rear wall 17 of the machine room niche 2 or in a side wall 18, directly opposite the inlet opening of the housing 5. The opposite opening of the housing 5 is inserted in a partition 19, which is the

Machine room niche 2 divided into two chambers 20, 21. The condenser-fan assembly 4 is located substantially in the chamber 20; the compressor 3 is housed in the chamber 21. The condenser-fan assembly 4 is mounted in the chamber 20 at a distance from the ground. When the fan 6 is running in the cleaning mode, dirt that dissolves from the condenser 9 and is not discharged directly through the openings 16 into the open, fall on a bottom 23 of the chamber 20. If the fan 6 later works again in the cooling mode, the flow velocity of the air at the bottom 23 of the chamber 20 is low, so that the dirt there is not sucked back into the condenser 9. At most, the circulating in the upper region of the chamber 19 from the openings to the condenser 9 toward air flow can cause the dirt on the bottom 23 is flushed in the direction of the partition 19 and so finally in a gap 22 between the housing 5 of the assembly 4 and the Floor 23 is pushed, in which he remains trapped safely. In this way, the trapped by the condenser 9 dirt trapped in the device is a

Avoidance of the user by ejected dirt avoided or at least limited. Fig. 6 shows a horizontal section through the engine room niche 2 of a

Refrigerating appliance according to another embodiment of the invention. The condenser 9 is here substantially tubular, wherein the wall of the tube through

Refrigerant lines 24 and connecting them, each related in the radial direction formed on the axis of the tube fins 25 is formed. The tube is closed on a side opposite the fan 6, be it as shown by a part of the condenser-fan assembly 4 forming plate 26 or by placement of the fan facing away from the end of the condenser 9 in direct contact with the side wall 18th This arrangement has the consequence that, when in cooling mode, the fan 6 sucks air through the condenser 9, the flow velocity is greater, the closer it comes to the longitudinal axis of the condenser 9. Conversely, when the air is blown through the condenser 9 in the cleaning operation, their speed decreases with increasing distance from the axis. An airflow that is still fast enough during the passage between the fins 25 to entrain deposited dust therefor, therefore, loses considerable speed as it approaches the walls of the engine room niche 2. This allows the dissolved dust to settle on the floor 23 of the engine room niche.

In the embodiment shown in Fig. 6, the back of the machine room niche 2 is largely open to allow a free inflow and outflow of air. While this is a suitable solution for a desk-mounted refrigeration device, it can lead to a fluidic short circuit and heat accumulation in a built-in appliance. In order to ensure here that air heated at condenser 9 and compressor 3 is not sucked up again immediately, and sufficient cold fresh air to be supplied, inlet and outlet openings of a channel, on which the air is passed through the device, must be widely spaced from each other , and it may be necessary

Inlet port of the channel to place on the front of the device. FIG. 7 shows a development of the embodiment of FIG. 6, in which a suction channel 27 extending below the bearing chamber 7 connects the chamber 20 of the machine room niche 2 with a front inlet opening. The intake passage 27 opens into the chamber 20 above the bottom plate 23, to prevent that on the bottom plate already deposited coarse dirt in a cleaning phase of the condenser from the at the mouth of the intake passage 27 into the chamber 20 relatively strong air flow detected and the outside transported where it could attract a user annoying. Fine dust that settles in the chamber not fast enough on the bottom 23, enters the intake passage 23 and for the most part over this into the open. To ensure that dust that is still in the intake 27 at the end of a cleaning phase, not immediately sucked back into the condenser, may be attached to a wall of the intake passage 27 of the intake flow oppositely oriented bristles 28.

If fresh air flows through the intake passage 5 in the cooling mode, it is still too slow in the vicinity of the bottom 23 to whirl up the dust lying there and for

Condenser 9 entrain. Their strength may be sufficient to move the dust at the bottom 23. This is exploited in which a projecting from the rear wall 17 of the niche 2 web 28 a bag 29 divides, in which the dust can collect.

Claims

1. Refrigerating appliance, in particular domestic refrigeration appliance, with a heat exchanger (9) and at least one fan (6) for driving an air flow through the

Heat exchanger (9), characterized in that the flow direction of the heat exchanger (9) is reversible.

2. Refrigerating appliance according to claim 1, characterized in that the fan (6)

between a the heat exchanger (9) blowing mode and a suction by the heat exchanger (9) operating mode can be switched.

3. Refrigerating appliance according to claim 2, characterized in that for switching between the operating modes, the running direction of a rotor of the fan (6) is variable.

4. Refrigerating appliance according to claim 2, characterized in that the fan a

Flap is assigned for switching between the operating modes.

5. Refrigerating appliance according to one of claims 2 to 4, characterized in that the fan (6) is arranged to work mainly in the aspirating mode.

6. Refrigerating appliance according to one of the preceding claims, characterized by a channel (27, 20, 21) on which by the fan (6) driven air is passed through the refrigerator

7. Refrigerating appliance according to claim 6, characterized in that the channel (27, 20, 21) on a side facing away from the fan (6) of the heat exchanger (9) has a portion (20) in which the speed of the fan (6 ) driven air flow is lower than in the heat exchanger (9).

8. Refrigerating appliance according to claim 6, characterized in that the channel (27, 20, 21) on a side facing away from the heat exchanger side of the fan a section in which the speed of a fan-driven airflow is lower than in the heat exchanger.

Refrigerating appliance according to claim 7 or 8, characterized in that the section (20) one of a main passage direction of the channel (27, 20, 21)

includes branching bag (22; 29).

Refrigerating appliance according to one of claims 6 to 9, characterized in that a wall of the channel (27, 20, 21) carries projections (28) which are directed against an airflow passing along the wall to the heat exchanger (9).

Refrigerating appliance according to one of claims 6 to 10, characterized in that in the channel (27, 20, 21) an air filter (15) is arranged.

Refrigerating appliance according to one of the preceding claims, characterized in that the heat exchanger (9) is a condenser.

Refrigerating appliance according to one of the preceding claims, characterized in that the heat exchanger (9), the fan (6) and a pipe section (5) connecting the heat exchanger (9) to the fan (6) form a structural unit (4).

are summarized.

Refrigerating appliance according to one of the preceding claims, characterized in that the fan (6) in the less frequently used of the two operating modes has a higher throughput than in the predominantly used.

Refrigerating appliance according to one of the preceding claims, characterized by an operating state display (14) at which the respectively selected

Flow direction is visible.