DE102008024325A1 - Cooling unit with coolant storage in the condenser and corresponding procedure - Google Patents

Abstract

It is to be proposed a cooling device, in particular household refrigerator / freezer combination device, with a simple structure in which each of at least two subjects can be switched off individually. According to the invention, therefore, a cooling device with a cooling circuit is proposed, wherein the cooling circuit a compressor (5), a condenser (6) with a cooling line (60) which is connected at its first end (61) to the compressor (5), a first Valve (11), which is connected to the second end (62) of the cooling line (60) of the condenser (6), a first evaporator (3) downstream of the first valve (11) and connected to the compressor (5) , and a second evaporator (4). A second valve (10) is connected between the two ends (61, 62) of the cooling line (60) of the condenser (6) and connected to the second evaporator (4) via a second outlet (10b), the second evaporator (4 ) is connected on the output side to the compressor (5). Advantageously, such a simple two-circuit system can be constructed with a single compressor and also due to the coolant storage in the second part (6b) of the condenser (6) to achieve an adjustment of the amount of refrigerant to the condenser or vice versa, resulting in increased energy efficiency.

Description

The The present invention relates to a refrigerator with a refrigeration cycle comprising: a compressor, a condenser with a cooling line, which is connected at its first end with a compressor, a first valve connected to the second end of the condenser cooling line connected, a first evaporator, which is connected downstream of the first valve and connected to the compressor, and a second evaporator. About that In addition, the present invention relates to a method for cooling a first compartment and a second compartment of a refrigerator, the refrigerator being a condenser, in which the coolant liquefied is, has.

Today's fridge-freezers are basically available in three versions: In a first version, the cooling is according to 1 realized by a single-circulation system. The fridge freezer has a freezer compartment 1 and a refrigerated compartment 2 on (in 1 also with GS: freezer and KS: refrigerator). In the freezer 1 there is a first evaporator 3 and in the cooling compartment is a second evaporator 4 , Refrigerant or refrigerant is in the freezer evaporator or first evaporator 3 at an injection point 7 injected. This is with the refrigerator compartment evaporator or second evaporator 4 connected and the refrigerant is from the second evaporator 4 aspirated. From there it gets into a compressor 5 and further into a condenser 6 directed. On the output side is the condenser 6 again with the injection point 7 on the first evaporator 3 connected.

According to a second embodiment according to 2 Cooling freeze combinations are also known which are a two-circuit system with a compressor 5 exhibit. After the compressor 5 the coolant flows into the condenser 6 and from there into a solenoid valve 8th , Depending on the switching position, the liquefied coolant is in an injection point 7 at the entrance of the evaporator 3 in the freezer 1 or to an injection point 9 of the evaporator 4 in the refrigerator compartment 2 guided. From the exit of the evaporator 3 of the freezer compartment 1 the coolant goes directly to the compressor 5 guided. From the exit of the evaporator 4 of the refrigerator compartment 2 the coolant is delivered to the entrance 10 of the evaporator 3 of the freezer compartment 1 recycled. As a result, the freezer compartment is always cooled when the refrigerator compartment cooling is switched on. This two-circuit system with a single compressor has one injection point 7 in the freezer 1 as well as an injection point 9 in the refrigerator compartment 2 , Between these two injection points 7 . 9 turns on the bistable magnetic field 8th , which is regulated by an electronics due to the cooling requirement of the two subjects. In this constellation, although the cooling compartment can be switched off separately, but the freezer compartment can not be switched off separately due to its coupling with the refrigeration compartment.

In addition, known Kühlgefrierkombinationen according to 3 also with a two-circuit system with two compressors 5 and 5 ' fitted. To the compressor 5 is a liquefier 6 and in turn the evaporator 3 of the freezer compartment 1 with appropriate injection point 7 connected. The exit of the evaporator 3 leads back to the compressor 5 , A similar cooling circuit is for the cooling compartment 2 built up. To the compressor 5 ' is a liquefier 6 ' connected the coolant through the injection point 9 to the evaporator 4 continues. The exit of the evaporator 4 is at the entrance of the compressor 5 ' coupled. Accordingly, the two refrigeration circuits for cooling compartment 2 and freezer, 1 completely separated from each other.

at the above representations as well as in the following embodiments the freezer compartment is located above the refrigerating compartment. As a general rule could the arrangement also be reversed. If necessary, that can refrigerated compartment and the freezer compartment can also be arranged side by side.

The basis 1 to 3 shown cooling units increase in their production costs in the order mentioned. At the same time, however, only the two-circuit systems allow separate adjustment of both compartment temperatures. In particular, the two two-cycle systems compete because the second compressor in the example of 3 leads to significantly higher costs, but thereby also allows the customer to disconnect both compartments separately when not in use.

The The object of the present invention is therefore to provide a refrigeration or Refrigerator, in particular a household fridge freezer to provide which cheaper Owns production costs and still allows, if necessary, each of two subjects can be switched off individually.

• – einen Verdichter,
• – einen Verflüssiger mit einer Kühlleitung, die an ihrem ersten Ende mit dem Verdichter verbunden ist,
• – einem ersten Ventil, das mit dem zweiten Ende der Kühlleitung des Verflüssigers verbunden ist,
• – einem ersten Verdampfer, der dem ersten Ventil nachgeschaltet und an den Verdichter angeschlossen ist, und
• – einem zweiten Verdampfer, weiterhin umfassend
• – ein zweites Ventil, das zwischen die beiden Enden der Kühlleitung des Verflüssigers geschaltet und mit einem zweiten Ausgang an den zweiten Verdampfer angeschlossen ist, wobei
• – der zweite Verdampfer ausgangsseitig mit dem Verdichter verbunden ist.

According to the invention this object is achieved by a cooling device, in particular household refrigerator / freezer combination device, comprising a cooling circuit comprising:

• A compressor,
• A condenser with a cooling line connected to the compressor at its first end,
• A first valve connected to the second end of the condenser cooling line,
• A first evaporator downstream of the first valve and connected to the compressor, and
• - A second evaporator, further comprising
• - A second valve which is connected between the two ends of the cooling line of the condenser and connected to a second output to the second evaporator, wherein
• - The second evaporator is connected on the output side to the compressor.

• – Kühlen des ersten Fachs ausschließlich mit einem ersten Teil des Verflüssigers,
• – Kühlen des zweiten Fachs mit einem zweiten und dem ersten Teil des Verflüssigers,
• – Speichern eines Teils des Kühlmittels in dem zweiten Teil des Verflüssigers, wenn das zweite Fach nicht gekühlt wird.

In addition, the invention provides a method for cooling a first compartment and a second compartment of a refrigerator, in particular household refrigerator / freezer combination device, wherein the cooling device, a condenser, in which the coolant is liquefied comprises

• Cooling the first compartment exclusively with a first part of the condenser,
• Cooling the second compartment with a second and the first part of the condenser,
• - Store a portion of the coolant in the second part of the condenser, when the second compartment is not cooled.

In Advantageously, it is possible build a two-circuit system with a single compressor, and above to ensure that two subjects of the device can be switched off separately.

Preferably If the valves are bistable solenoid valves. In order to can for both Valves are used the same component, so the logistics costs sinks. One of the valves may have only one outlet zuzulöten.

The Valves are in accordance with a special embodiment in particular only tight to a predetermined pressure. To this Way lets to realize an overpressure protection in an advantageous manner.

The Valves can in particular be controlled so that immediately after switching of the compressor for a predetermined time only the second evaporator with coolant flows through becomes. This means that the compressor does not have to withstand increased pressure during startup work.

alternative can the valves preferably also be controlled so that before switching on of the compressor both valves or only the first valve will be opened. Even so lets to realize a pressure equalization before the start of the compressor, so that the compressor does not work against increased pressure at start-up got to.

Of the Part of the condenser from the first end of the cooling line up to the second valve can be beneficial to the performance be adapted to the second evaporator. That way you can an optimized cooling system to reach.

Especially advantageous when storing a portion of the coolant immediately at the end of a runtime, during which the second compartment is cooled. In this phase, most liquid coolant is in circulation and can be stored in this state.

other Further developments of the invention are given in the dependent claims.

The invention and its developments are explained in more detail below with reference to drawings:
Each show schematically:

1 a one-circuit system for a refrigerator with a freezer and a cooling compartment according to the prior art;

2 a two-cycle system with a single compressor according to the prior art;

3 a two-cycle system with two compressors according to the prior art;

4 a two-circuit system with a single compressor and two independently controllable evaporators, and

5 An embodiment of a two-cycle system according to the invention with a single compressor and a storage option of the coolant in the condenser.

The basis of 5 illustrated embodiment illustrates a preferred embodiment of the present invention. For a better understanding of the invention, however, yet another two-cycle system will be explained.

First, it is necessary to clarify why in the two-cycle system according to 2 not both compartments can be switched off separately. The solenoid valve 8th allowed to switch between the two circuits. Will the freezer 1 controlled, so is refrigerant in the freezer or its evaporator 3 injected and directly from this to the compressor 5 sucked out. If, on the other hand, the cooling compartment is actuated, then refrigerant will enter the cooling compartment evaporator 4 injected. There it will be in the freezer compartment evaporator 3 passed and through the entire freezer evaporator 3 through to the compressor 5 sucked out. As a result, the freezer is always cooled in the event that the cooling compartment is controlled. Accordingly, you can indeed the refrigerator 2 shut down separately, but that freezer 1 can not be switched off separately.

A direct solution to this problem is in 4 outlined. There is the refrigerator compartment evaporator 4 directly from the compressor 5 sucked, ie the two suction pipes for sucking the one hand, the freezer compartment evaporator 3 and on the other hand, the refrigerating compartment evaporator 4 are brought together at one point separately from both evaporators and then from there to the compressor 5 directed. The remaining structure of the two-cycle system corresponds to that of 2 , This system can be referred to as XOR system because either the refrigerator compartment 2 or the freezer 1 is cooled, but never both at the same time. This construction of the evaporator 3 . 4 solves the initial problem, but a new problem is emerging. In typical devices, the freeze-thaw evaporators are significantly larger than the refrigerated compartment evaporators. This is due to various requirements and not least to the optimization of energy efficiency. But this requires the freezer compartment evaporator 3 significantly more refrigerant than the refrigerator compartment evaporator 4 to be operated efficiently. The XOR device can not be optimized for both subjects. This was also according to the system 2 not possible. In this system, namely, the amount of refrigerant through the freezer 1 Are defined. This is too much for the refrigerator compartment 2 , but because of the refrigerator compartment evaporator 4 over the freeze-thaw evaporator 3 is sucked off, the excess coolant is then used to the freezer 1 to cool and is therefore not lost. If the XOR device is designed the same way, the excess refrigerant will flow into the intake manifold when the cooling compartment is actuated, where it will evaporate. Energy is wasted because the cooling of the intake manifold has no cooling benefit. Even more negative is that the suction pipe at the point where it is in contact with the ambient air, may not be cooled below the dew point, otherwise it can lead to condensation and thus rust. To circumvent this last problem, in turn, a collector can be installed in the foam, but this leads to increased costs. If you put the amount of refrigerant not on the freezer, but on the refrigerator compartment, then the entire unit will be energetically less efficient. In other words, the XOR device would meet the requirements, but it would be less efficient.

The problem of the XOR circuit is that the amount of refrigerant in the circuit can not be adapted to the particular situation. The following together with 5 described solution according to the invention starts at this point. The evaporators 3 . 4 and the suction pipes correspond to those of the XOR circuit of 4 but on the side of the condenser 6 is the system changed. In particular, the here preferably tubular condenser 6 in a first section 6a and a second subsection 6b divided. The condenser 6 therefore has a cooling line 60 with a first end portion 61 and a second end portion 62 , At a suitable location between these two end sections is a solenoid valve 10 (hereinafter referred to as "second solenoid valve"). The second output of the bistable solenoid valve 10 leads to the injection point 9 of the refrigerator compartment evaporator 4 ,

The second end section 62 the cooling line 60 the here preferably tubular condenser 6 is with another solenoid valve 11 (hereinafter referred to as "first solenoid valve") connected. The output of this first solenoid valve 11 is at the injection point 7 of the freezer evaporator 3 guided.

The second section 6b the here preferably tubular condenser 6 can be used here as a storage area, so that in case of cooling the refrigerator compartment 2 (Also called first compartment) in this storage area, a portion of the refrigerant can be cached. In 5 a concrete embodiment is shown which has such a memory. As already indicated above, the second subsection is 6b of the liquefier 6 by means of the second solenoid valve 10 disconnected, ie the second solenoid valve 10 has two outputs 10a and 10b , The first exit 10a go to the second section 6b of the liquefier 6 or to the memory. Behind it lies the first solenoid valve 11 on the way of the refrigerant to the freezer compartment evaporator 3 , The second exit 10b of the second solenoid valve 10 directs the refrigerant from the first condenser part 6a directly into the cooling compartment evaporator 4 , The first solenoid valve 11 has no second outlet and serves only as a shut-off valve. Even if bistable solenoid valves are used in the present case, it remains unavoidable to implement the cooling system with other valve types.

In the event that the freezer 1 to be cooled as a second compartment, the entire amount of cold should be used. This is the first solenoid valve 11 and the second solenoid valve 10 switched on, so that the refrigerant from the first section 6a of the liquefier 6 to the second subsection 6b running. This is the entire liquefaction 6 and used all the refrigerant. At the end of the duration of the freezer cooling process 1 ie if the freezer 1 is cold enough or is not cooled further for other reasons, will be the first valve 11 closed and the second valve 10 switched so that the refrigerant from the first condenser part 6a in the refrigerator compartment evaporator 4 flows. As a result, a significant amount of refrigerant in the second Verflüssigerteil 6b or stored in memory because the at the end of the runtime, it is largely filled with liquid refrigerant. If following the compressor 5 not running, then it will be after some time to equalize the pressure in the refrigerant circuit between the evaporators 3 . 4 and the first subsection 6a of the liquefier 6 come.

When pressure equalization typically there is a pressure between 1-2 bar. In the blocked condenser section 6b Typically, a pressure in the range of 3-6 bar prevail. Accordingly, the valves must 10 . 11 can keep these pressures tight, of course, especially when the freezer is turned off, the appropriate amount of refrigerant must be permanently locked away. This shutting off is expediently always at the end of a cooling period of the freezer compartment 1 because at first it is undetermined what will happen afterwards. The entire system of the refrigerator-freezer is prepared in particular so as to have a refrigeration period of the refrigerator compartment next 2 can come.

In the event that the refrigerator compartment 2 to be cooled as the first compartment, is between the first and the second solenoid valve 10 . 11 in the memory or in the second subsection 6b of the liquefier 6 already locked away refrigerant. The second solenoid valve 11 is then switched so that refrigerant in the refrigerator compartment evaporator 4 is injected. This stands for the cooling period of the refrigerator compartment 2 less refrigerant available. The size of the memory, ie the second condenser part 6b , Is suitably adjusted so that the remaining amount of refrigerant in the system optimal for the refrigerator compartment 2 is measured. The amount is determined by the size of the reservoir, in particular the length of the second section of the tubular condenser, and the condenser pressure at the end of the freezer compartment cooling period (second compartment). The condenser pressure is variable depending on the ambient conditions - and thus never exactly the same amount of refrigerant is locked away. Accordingly, the design of the condenser is made under different environmental conditions. If the conditions of use are not to be limited too much, one of the two valves can also be designed so that it is not tight above a certain storage pressure. In this case, the pressure will drop to this predetermined pressure and adjust the amount of stored refrigerant. In principle, such a pressure limitation is possible, but it is usually not necessary because small fluctuations of the weggesperrten amount of the refrigerant have no major impact.

• 1. Erstens kann man nach Einschalten des Verdichters 5 zunächst für eine kurze Zeit das Kühlfach 2 kühlen, bis sich im ersten Verflüssigerteil 6a ebenfalls ein Druck zwischen 4–6 bar eingestellt hat und der Verdichter sich auf diesen Arbeitspunkt eingespielt hat. Es handelt sich also eigentlich um ein reines Anlaufproblem des Verdichters. Im Anschluss an die Druckerhöhung im ersten Verflüssigerteil 6a kann man auf die Gefrierfachkühlung umstellen.
• 2. Eine zweite Möglichkeit, den Anlaufproblemen des Verdichters zu begegnen, besteht darin, die beiden Magnetventile 10, 11 zu öffnen oder nur das erste Magnetventil 11 zu öffnen, bevor der Verdichter 5 angeschaltet wird. Dann wird zweckmäßigerweise gewartet, bis sich der Druck so weit ausgeglichen hat, bis der Verdichter 5 angeschaltet werden kann. Dies dauert typischerweise 1–5 Minuten. In der Regel kann aber die Kühlung für diese Zeit ohne Weiteres ausgesetzt werden, ohne dass sich das Gerät zu stark erwärmt.

Furthermore, there is another edge problem: when the compressor 5 is switched off because there is no tray at the moment 1 . 2 must be cooled and then later the system, in particular the control logic device, the refrigerator / freezer combination device detects that the freezer is to be cooled, so the compressor must be turned on, the first solenoid valve 11 opened and the second solenoid valve 10 be switched so that the refrigerant from the first condenser part 6a in the second condenser part 6b running. Since in the second condenser part 6b or storage liquid refrigerant was stored at a pressure typically between 3-6 bar, the compressor has 5 to work directly against this pressure during start-up. Most typical compressors are not able to do this. There are two ways to solve this problem:

• 1. First, after switching on the compressor 5 first for a short time the refrigerator compartment 2 cool until in the first condenser part 6a also set a pressure between 4-6 bar and the compressor has adjusted to this operating point. It is therefore actually a pure start-up problem of the compressor. Following the pressure increase in the first condenser section 6a you can switch to the freezer compartment cooling.
• 2. A second way to counteract the start-up problems of the compressor is to use the two solenoid valves 10 . 11 to open or only the first solenoid valve 11 to open before the compressor 5 is turned on. Then it is expediently waited until the pressure has been compensated so far until the compressor 5 can be turned on. This typically takes 1-5 minutes. In general, however, the cooling can be readily suspended for this time, without the device being overheated.

The proposed cooling system according to the invention with a memory allows the amount of refrigerant in the circuit to be adapted to the respective situation. If the freezer 1 Is cooled, the full amount of refrigerant is necessary and this is then available, so that the freezer 1 is optimally cooled. At the end of each freezer cooling period, liquid refrigerant is shut off in the storage area. As a result, only so much refrigerant is available in the system in the case of a refrigeration compartment cooling system, as for the smaller refrigerated compartment evaporator 4 necessary is. This will make this evaporator 4 not overcrowded and the intake manifold not too cold. The refrigerator compartment can be optimally adjusted. In addition, refrigerant is not vaporized at locations where it does not serve cooling. This results in a high energy efficiency of the entire system, at least a much better energy efficiency than in the simple XOR system according to 4 ,

By the special choice of the memory as a second part 6b of the liquefier 6 another advantage is achieved. If namely with the lower Käl the cooling compartment 2 is cooled, is sufficient for the smaller amount of refrigerant compared to the simple XOR_System of 4 shorter condenser 6 to liquefy the refrigerant. In the embodiment of 5 is the liquefier 6 simultaneously reduced when the amount of refrigerant is reduced. This reduces the pressure losses of the refrigerant through the condenser, which in turn shows in an increased efficiency. This follows from the fact that there is an optimal condenser size for a cycle, so that the energy efficiency is worse, not only if the condenser 6 gets smaller (ie can dissipate less heat), but also when it gets bigger. This is due to the fact that the heat exchange is sufficient, but now the higher pressure losses when extending the flow-through pipe hit more heavily than the increased heat exchange. Accordingly, the solution shown also allows the condenser size to optimally adapt to the cycle.

One Another important advantage of the solution according to the invention is that the Refrigerant in the Memory liquid present and also liquid remains. To the transition in the gas phase lacks space, d. H. Ultimately, the high holds Pressure at the device ambient temperature the refrigerant liquid. This is the energy that was used up for liquefaction, not lost, but is used again when the freezer chilled shall be.

The principle of the invention is not limited to combinations of refrigerator and freezer, but can also extend devices with multiple compartments (refrigerator compartment, freezer, zero degree compartment, etc.) and also on so-called "no-frost systems". In addition, not always the freezer compartment evaporator 3 be the larger evaporator. It is crucial that the amount of refrigerant in the system can be adjusted.

Claims (10)

Cooling appliance, in particular household refrigerator / freezer combination appliance, with a cooling circuit comprising: - a compressor ( 5 ), - a liquefier ( 6 ) with a cooling line ( 60 ), which at their first end ( 61 ) with the compressor ( 5 ), - a first valve ( 11 ) connected to the second end ( 62 ) of the cooling line ( 60 ) of the liquefier ( 6 ), - a first evaporator ( 3 ), the first valve ( 11 ) and to the compressor ( 5 ), and - a second evaporator ( 4 ), characterized by - a second valve ( 10 ), which is between the two ends ( 61 . 62 ) of the cooling line ( 60 ) of the liquefier ( 6 ) and with a second output ( 10b ) to the second evaporator ( 4 ), wherein - the second evaporator ( 4 ) on the output side with the compressor ( 5 ) connected is. Refrigerator according to claim 1, wherein the valves ( 10 . 11 ) are bistable solenoid valves. Refrigerator according to claim 1 or 2, wherein the valves ( 10 . 11 ) are only tight to a predetermined pressure. Refrigerator according to one of the preceding claims, wherein the valves ( 10 . 11 ) are controlled so that immediately after switching on the compressor ( 5 ) for a predetermined time only the second evaporator ( 4 ) is flowed through with coolant. Refrigerator according to one of claims 1 to 3, wherein the valves ( 10 . 11 ) are controlled so that before switching on the compressor ( 5 ) both valves ( 10 . 11 ) or only the first valve ( 11 ) is opened. Refrigerator according to one of the preceding claims, wherein the part ( 6a ) of the liquefier ( 6 ) from the first end ( 61 ) of the cooling line ( 60 ) to the second valve ( 10 ) to the performance of the second evaporator ( 4 ) is adjusted. Method for cooling a first compartment ( 2 ) and a second subject ( 1 ) of a refrigerator, in particular household refrigerator / freezer combination device, wherein the refrigerator is a condenser ( 5 ), in which the coolant is liquefied, characterized by - cooling the first compartment ( 2 ) exclusively with a first subsection ( 6a ) of the liquefier ( 6 ), - cooling the second compartment ( 1 ) with a second subsection ( 6b ) and the first subsection ( 6a ) of the liquefier ( 6 ), and - storing a part of the coolant in the second subsection ( 6b ) of the liquefier ( 6 ), if the second compartment ( 1 ) is not cooled. Method according to claim 7, wherein the storage of a part of the coolant takes place directly at the end of a running time during which the second compartment ( 1 ) is cooled. Method according to claim 7 or 8, wherein the cooling device comprises a compressor ( 5 ) and immediately after switching on the compressor ( 5 ) for a predetermined time only the first compartment ( 2 ) is cooled. Method according to claim 7 or 8, wherein the cooling device comprises a compressor ( 5 ) and before Turning on the compressor ( 5 ) the storage of the part of the coolant is terminated.