EP2531784A1

EP2531784A1 - Refrigeration device and refrigerating machine therefor

Info

Publication number: EP2531784A1
Application number: EP11701787A
Authority: EP
Inventors: Peter Nalbach; Volker Braun
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2010-02-01
Filing date: 2011-01-21
Publication date: 2012-12-12
Also published as: CN102741625A; RU2012134985A; WO2011092116A1; DE102010001458A1

Abstract

The invention relates to a refrigeration device for a combination refrigerating appliance such as a household refrigerator-freezer combination, comprising a condenser (8) and at least two evaporators (3, 4) which are connected in parallel circuitry to an electrically controlled, multistable selector valve (7) and can be selectively supplied with coolant via the selector valve (7). According to the invention, a series circuit of a first current-controlled switch (18; 19) having PTC resistor characteristics and of the selector valve (7) is connected electrically parallel to the condenser (8).

Description

Refrigerating appliance and chiller for it

The present invention relates to a refrigerator for a combination domestic refrigeration appliance, i. for a refrigeration device with at least two storage compartments, which can be kept at different temperatures, as well as the refrigeration device itself.

There are various types of chillers for such combination refrigerators known. In the simplest type, a compressor, a freezer compartment evaporator and a standard refrigeration compartment evaporator are connected in series in a single refrigerant circuit. This type of chiller works with a very simple control, in which, as with conventional refrigerators with a single compartment by a

Temperature sensor controlled electromechanical switch, such as a bimetallic element is attached to one of the compartments to close a supply circuit of the compressor when the temperature in the compartment exceeds a predetermined limit. Such a chiller allows only the simultaneous cooling of both compartments, and independent control of the temperature in both compartments is not possible.

A second type of combination refrigerator includes independent of each other

Refrigerators for normal refrigerated and freezer. This type therefore allows an independent temperature control of both subjects and achieves a very good

Energy efficiency, however, the cost of the two separate chillers are high. In practice, therefore, a very common type in which a single compressor via a switching valve either a freezer evaporator or a

Standard refrigerated compartment evaporator supplied. To control the switching valve, an electronic circuit is used, which continuously, even if the switching valve is not switched, generates a power loss that affects the overall efficiency of the device. The abandonment of such a circuit could both the

Reduce energy consumption of the device as well as its cost.

The aim of the present invention is therefore to provide a refrigeration machine for a combination refrigerator, which allows independent temperature control of different subjects and their control without constantly consuming energy-consuming electronic components or their energy consumption in a dormant state in which the Operation of the chiller is not changed, at least substantially less than at times when the controller intervenes to the operating state of

Chiller to change.

The object is achieved by connected in a refrigerator for a combination refrigerator such as a domestic refrigerator-freezer with a compressor, at least two connected in parallel with an electrically controlled multi-stable switching valve and selectively acted upon by the switching valve with refrigerant

Evaporate a series circuit of a first current-controlled switch with

PTC thermistor characteristic and the switching valve is electrically connected in parallel with the compressor. As long as the compressor is switched off and the current-controlled switch is de-energized, the latter is permeable. Thus, when switching on the compressor and the switching valve is energized first and thereby can change its switching state. If after a short time the current-controlled switch responds, it interrupts the flow of current through the switching valve, so that there is essentially no

Power loss is incurred until it is switched again. Thus, a control of the switching valve without continuously power consuming components is possible.

Preferably, the first current-controlled switch is connected in series with a diode in order in each case to pass only a half-wave of an applied alternating voltage and to apply the switching valve with a unipolar voltage whose sign defines the switching direction of the switching valve. Complementarily, for switching the switching valve in the opposite direction, a series circuit of a second current-controlled switch and a second diode is connected in parallel to the series connection of the first current-controlled switch and the first diode, wherein the second diode is polarized antiparallel to the first.

Conveniently, a first controlled by a temperature sensor switch with an input terminal and two each alternatively with the input terminals

connected output terminals, wherein each of the output terminals is connected to one of the series circuits of a current-controlled switch and a diode. This arrangement allows the determination of the switching direction of the switching valve in dependence on a prevailing at the temperature sensor

Temperature. If this temperature is the temperature of a compartment of a refrigerator, can be determined depending on this temperature, whether the switching valve, an evaporator of this compartment supplied with refrigerant or the evaporator of the

Refrigerant supply shuts off.

As drive units of refrigerators electric motors are common, which comprise a main winding and an auxiliary winding, wherein the auxiliary winding is to be acted upon in a start-up phase of the motor with power to specify a running direction of the motor, or to ensure a start of the motor, even if this is in an equilibrium position with respect to the electromagnetic forces generated by the main winding. In order to apply power to the auxiliary winding only in the starting phase of the motor, it may also be associated with a current-controlled switch.

According to a simple embodiment of the invention, the current-controlled switch, via which the auxiliary winding can be supplied with current, is identical to the first current-controlled switch.

However, the current-controlled switch supplying the auxiliary winding may also be a third different from the aforementioned switches

act current-controlled switch, and a series connection of this third

current-controlled switch and the auxiliary winding is connected in parallel to the switching valve. Thus, current-controlled switches can be used, each with an ideal adaptation to the properties, in particular power and switching times, of the auxiliary winding or of the switching valve. The amount of current required to switch the switching valve is generally low, and many types of current-controlled switches do not switch at currents greater than the switching current of the switching valve. In order to use such types of current-controlled switches, it is appropriate to a

Load resistance to the switching valve in parallel and with at least the first

provide current-controlled switch in series.

Compressor and switching valve are preferably connected in parallel to each other electrically and together with a second controlled by a temperature sensor switch in Connected series. This second switch controlled by a temperature sensor can be provided on a second compartment of a combination refrigerator in order to

Detect cooling demand in this compartment and operate the compressor when cooling demand exists. Whether the second compartment is actually cooled when the compressor is operating depends on the position of the first switch controlled by a temperature sensor. It may therefore be that first cooling demand of the first compartment is satisfied, until the first switch controlled by a temperature sensor switches over and enables the supply of the second compartment with refrigerant.

The current-controlled switches can be real PTC thermistors whose conductivity is temperature-dependent and which are heated by a current flowing through them, so that the conductivity also depends indirectly on the current; however, it is also possible to use electronic components, for example based on triacs, which simulate the current-dependence of the conductivity of such a PTC thermistor, without necessarily having the temperature-conductivity characteristic of the PTC thermistor.

Basically, both the first controlled by a temperature sensor switch on a colder and the second controlled by a temperature sensor switch can be arranged on a warmer of two compartments of the refrigerator, as well as vice versa. Basically, one will generally attach the second temperature-controlled switch to the compartment which has more frequent cooling requirements so that, when cooling demand occurs, the compressor's start-up will not be unnecessarily delayed. It is also expedient if at least a part of the evaporator of the compartment to which the second switch controlled by a temperature sensor is mounted, and the evaporator of the compartment to which the first switch controlled by a temperature sensor is mounted, are flowed through in series of refrigerants. This ensures that when the compartment of the second switch needs cooling and therefore the compressor is started, at least part of the available cooling capacity from the beginning of the compressor run time also benefits the second compartment. Further features and advantages of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings in which:

Fig. 1 is a schematic representation of the refrigerator of a

Combination refrigerator according to the present invention;

Fig. 2 is a block diagram of the electrical components of

Refrigerating machine according to a first embodiment;

3 is a block diagram of the electrical components according to a second embodiment; and

4 is a block diagram of the electrical components according to a third embodiment of the invention.

Fig. 1 shows schematically a refrigerator of a household refrigerating appliance with a freezer compartment 1 and a normal refrigeration compartment 2. The subjects 1, 2 are associated with evaporator 3 and 4 respectively. Injection points 5, 6 of the evaporator 3, 4 are connected to one output of a bistable solenoid valve 7. An outlet of the evaporator 4 of the

Normal cooling compartment 2 is connected to an input of the evaporator 3 of the freezer compartment 1, so that together with the evaporator 4, the evaporator 3 is always cooled. In the evaporator 3 can be provided largely separate lines for injected at the injection point 5 refrigerant and for the refrigerant originating from the evaporator 4, which meet only in the vicinity of an outlet of the evaporator 3, or it can essentially a single line on the

Evaporator 3 may be provided, in which the refrigerant from the evaporator 4 opens shortly after the injection point 5.

From the evaporator 3 extracted refrigerant passes through a compressor 8 and passes through a condenser 9 back to the solenoid valve 7, from where it is either the

Injection point 5 or the injection point 6 is supplied. At each of the two compartments 1, 2 a controlled by a temperature sensor 22 switch 10 or 1 1 is mounted (see Fig. 2). As a temperature sensor 22 and at the same time as a movable element of the switch 10, 1 1 can serve a bimetallic element; but it can also be sensor 22 and switch 10, 1 1 spatially separated by about an electronic sensor is mounted as a temperature sensor 22 to a tray 1 or 2 and as a switch 10, 1 1 driven by a measuring signal of the sensor

Power transistor is used. In the following functional description it is assumed that the switch 10 on the freezer compartment 1 and the switch 1 1 am

Normal cooling compartment 2 is arranged, but a reverse placement would also be possible.

Furthermore, in Fig. 2, a source of AC supply voltage 12, a main winding of a motor of the compressor 8 with 13, an auxiliary winding with 14, two diodes 15 and 16 and PTC resistors with 17, 18 and 19 respectively. When the temperature in the freezer 1 via a set on the switch 10

Limit increases, the switch 10 closes, and the supply voltage from the source 12 is applied to the main winding 13 and the series connection of the auxiliary winding 14 with the PTC 17 at. The PTC 17 is initially conductive, so that a current pulse through the

Auxiliary winding 14 flows, which can start the engine of the compressor 8 reliably.

At the same time, the AC supply voltage across the switch 1 1 depending on its position either on a series circuit of the solenoid valve 7 with the PTC 18 and the diode 15 or a series circuit of the solenoid valve 7 with the PTC 19 and the diode 16 at. Thus, flows through the solenoid valve 7, first a unipolar current whose direction due to the opposite polarity of the diodes 15, 16 from the position of the

Switch 1 1 depends. If the temperature of the normal cooling compartment 2, which is exposed to the switch 1 1, is above a threshold set at the switch 1 1, there is

Cooling requirement also in the normal cooling compartment 2, and via the PTC 18 and the diode 15, a current flows, which brings the solenoid valve 7 in that position in which it supplies the evaporator 4 of the normal cooling compartment 2. Since in this position the evaporator 3 is connected downstream of the evaporator 4 in the refrigerant circuit, both compartments 1, 2 are effectively cooled, although the power attributable to the normal refrigeration compartment 2 is generally the higher. The respectively flowing when closing the switch 10 through the solenoid valve 7

Switching current leads to heating of the PTC 18 and thus to its transition to the blocking state. The resistance value of the PTCs is typically about 50 Ω in the transient state and about 100 kΩ in the off state. Thus, after the solenoid valve 7 has assumed the desired position, the flow of current through the solenoid valve 7 essentially collapses, and possibly only a small residual current which is required in order to maintain the blocking state of the PTC 18 flows. The power consumption of the solenoid valve 7 is then negligible, and the only load in the circuit of Fig. 2, which receives a significant power is the main winding thirteenth

If in the course of the operation of the compressor 8, the temperature of the normal refrigeration compartment 2 decreases so much that the switch 1 1 changes its state, voltage is present at the time permeable PTC 19 at. The current now flowing through PTC 19 and diode 16 puts the solenoid valve 7 in its second position, in which the

Evaporator 3 is supplied with refrigerant alone. Again, a short time of current flow is sufficient to put the PTC 19 in the blocking state and to bring the current flow through the solenoid valve 7 substantially to a standstill.

The solenoid valve 7 in the energized state typically has a power of about 10 W, corresponding to a current consumption of almost 50 mA, when the voltage of the voltage source 12 is 220 V. Such current is low compared to the switching currents of most PTCs available on the market. In order to be able to use inexpensive, well-priced types for the PTCs 18, 19, it is desirable to provide more current flow through the PTCs 18 or 19 at times when the solenoid valve 7 switches. For this purpose, a load resistor 20, as shown in dashed lines in Fig. 2, be connected in parallel to the solenoid valve 7. The influence of the power loss of the resistor 20 on the efficiency of the entire refrigerator is negligible, since the resistor 20 is energized only as long as the PTCs 18, 19 need to switch, typically 100 to 200 ms long.

FIG. 3 shows a modified block diagram in which the number of PTCs is reduced by one compared to FIG. Same components are in Fig. 3 with the same Reference numbers as shown in Fig. 2 and will not be described again. The essential difference between the two embodiments is that in Fig. 3 the

Auxiliary winding 14 is offset to the occupied in Fig. 2 by the load resistor 20 space. The current consumption of the parallel circuit of solenoid valve 7 and auxiliary winding 14 is sufficient to ensure a safe switching of the PTCs 18, 19, even if they are used for these common types with a tripping current of 100 mA or above.

A disadvantage of this variant is in comparison to FIG. 2 enlarged power loss, as induced by the operation of the compressor 8 in the auxiliary winding 14 voltages can drive a current flow through the solenoid valve 7 even when the solenoid valve 7 through the switch 1 1 and the PTCs 18, 19 is disconnected from the voltage source 12.

This problem can be avoided in the embodiment shown in Fig. 4, in which the auxiliary winding 14 is connected in series with the solenoid valve 7. In order to ensure a sufficient flow of current through the auxiliary winding 14 when closing the switch 10, a load resistor 21 is provided parallel to the solenoid valve 7. In the case of this load resistor 21, as in the case of the resistor 20, it may be a simple ohmic resistance, but the use of a PTC is also conceivable. The latter is particularly useful to prevent switching of the switch 1 1, that when the compressor 8 is running, a switch-on pulse is applied to the auxiliary winding 14, which could interfere with the running of the compressor motor. However, such a PTC 21 should be slower than the PTCs 18, 19 to ensure that current flow through the auxiliary winding 14 does not prematurely begin when the compressor motor starts up

is canceled.

Claims

claims

Refrigerating machine for a combination refrigerator, such as a household refrigerator-freezer, with a compressor (8), at least two in

Parallel connection with an electrically controlled multistable switching valve (7) and connected via the switching valve (7) selectively with refrigerant

acted upon evaporators (3, 4), characterized in that a series connection of a first current-controlled switch (18; 19) with

PTC thermistor characteristic and the switching valve (7) with the compressor (8) is electrically connected in parallel.

A refrigerating machine according to claim 1, characterized in that the first current-controlled switch (18; 19) is further connected in series with a first diode (15; 16) and in that the series connection of the first current-controlled switch (18; 19) and the first diode (15; 16) a series connection of a second current-controlled switch (19; 18) and a second diode (16; 15) is connected in parallel, wherein the first and the second diode (15, 16) are antiparallel poled.

Chiller according to Claim 2, characterized in that a first switch (11) controlled by a temperature sensor has one input terminal and two output terminals alternatively connected to the input terminals and in that one of the current-controlled switch-diode series circuits (18, 15; 19, 16) is connected.

Refrigerating machine according to one of the preceding claims, characterized in that the compressor (8) has a motor with a main winding (13) and a via at least one current-controlled switch (17; 18, 19) can be acted upon with power auxiliary winding (14). Chiller according to claim 4, characterized in that the at least one current-controlled switch, via which the auxiliary winding (14) can be acted upon by current, the first current-controlled switch (18, 19).

Chiller according to claim 4, characterized in that the at least one current-controlled switch, via which the auxiliary winding (14) can be acted upon by current, a third current-controlled switch (17) and that a series connection of the third current-controlled switch (17) and the

Auxiliary winding (14) to the switching valve (7) is connected in parallel.

Chiller according to one of the preceding claims, characterized

characterized in that a load resistor (20) is connected in parallel with the switching valve (7) and in series with at least the first current-controlled switch (18; 19).

Chiller according to one of the preceding claims, characterized

characterized in that the compressor (8) and the switching valve (7) are connected in parallel with each other and in series with a second switch (10) controlled by a temperature sensor.

Chiller according to one of the preceding claims, characterized

in that at least one of the current-controlled switches (17; 18; 19) is a PTC thermistor.

Chiller according to one of the claims, characterized in that at least one of the current-controlled switches (17; 18; 19)

Semiconductor device is.

Domestic refrigerating appliance with a refrigerating machine according to claim 8 and claim 3, characterized in that the first and the second temperature-controlled switch (1 1; 10) are each attached to one of two compartments (1; 2) of the refrigerating appliance.

12. Domestic refrigerating appliance according to claim 1 1, characterized in that the first temperature-controlled switch (1 1) on a colder and the second

Temperature-controlled switch (10) on a warmer of the two compartments (1, 2) is mounted.

13. Domestic refrigerating appliance according to claim 1 1, characterized in that the first temperature-controlled switch (1 1) on a warmer and the second temperature-controlled switch (10) on a colder of the two compartments (1, 2) is mounted.

14. Household refrigerating appliance according to one of claims 1 1 to 13, characterized

in that the second temperature-controlled switch (10) is arranged on the compartment at which cooling demand occurs most frequently.

15. Household refrigerating appliance according to one of claims 1 1 to 14, characterized

characterized in that at least part of the evaporator (3) of the compartment (1) to which the second temperature-controlled switch (10) is attached and the evaporator (4) of the compartment to which the first temperature-controlled switch (10) is attached, flowed through in series of refrigerant.