DE102006061091A1 - Refrigerator with at least two thermally separated compartments - Google Patents

Abstract

The refrigerating appliance has two blowers (21,21') separated thermally from each other. Each of the blowers is assigned to an evaporator (2,2') by which an expansion valve and the evaporator are switched one after the other in a refrigeration circuit (1) passing through the coolant. Two states are adjusted in an expansion valve with different non disappearing flow rate coefficient. An independent claim is also included for a method for operating the refrigerating appliance.

Description

The The invention relates to a refrigerator with at least two thermally separated compartments whose Evaporator along with a compressor and a condenser in a cooling circuit and from the compressor when signaling a refrigeration demand in the subjects with liquid refrigerant be charged, wherein the amount of cold contributing to the cooling is controllable. Furthermore, the invention relates to a for operating this Cooling furniture suitable Method.

to Control of different subjects a refrigerated cabinet Different temperature levels are very different configurations known from refrigeration furniture.

For example, in German Auslegeschrift DE 23 50 998 described a refrigeration cabinet with single circuit, which is designed inexpensively with only a single entry point for the refrigerant in the evaporator. Here, a freezer compartment and a normal refrigeration compartment each evaporator are assigned, which are connected in series in the refrigeration cycle. However, this series connection of the evaporator has the disadvantage that the dimensioning of the individual evaporator must be made according to the refrigeration demand existing in the individual subjects, or the temperature requirements given there. Consequently, the design of the evaporators can not be optimized with regard to a desired energy efficiency, since for this purpose the evaporators would have to be designed as large as possible. It is also of particular disadvantage that the temperature of the individual compartments can not be adjusted independently of each other, since in such refrigeration units with cooling required in a downstream in the refrigerant flow compartment also takes place in the upstream of this compartment subjects cooling.

In order to be able to cool this as independently of each other in refrigerated cabinets with multiple refrigerators, it is proposed to assign the individual refrigerators individually controlled cooling circuits. Such refrigeration furniture, for example, in the German patents DE 35 08 805 A1 or DE 40 20 537 A1 described. The evaporators associated with the individual cooling compartments are connected in parallel with one another in a refrigerant circuit. The entry points of the refrigerant in these evaporators have shut-off throttle valves. These throttle valves are individually controlled by a temperature control and thereby opened when a refrigeration demand is detected in the respective refrigeration compartment. In the in the DE 35 08 805 A1 described cooling furniture is provided in the refrigerant circuit in front of a branch leading to the evaporators, a reservoir for the intermediate storage of liquid refrigerant. From this it is possible to introduce additional refrigerant into the refrigerant circuit in a targeted manner by heating the reservoir in the event of an increased demand for refrigerant, in particular during simultaneous operation of both evaporators. In the in the DE 40 20 537 A1 described cooling furniture, the refrigerant to be introduced into the evaporator is withdrawn from the condenser according to its needs for one or simultaneously at several sampling points. A disadvantage of this prior art that, for the purpose of controlling the resulting from the connection or disconnection of the individual evaporator, variable amount of refrigerant energy-consuming storage means or inefficiently used condenser can be used. The parallel arrangement of several evaporators due to the dual design of the injection system (valve, throttle capillary, injection point) leads to significant additional costs compared to single circuits.

A single circuit, which is cost-effective and energy-efficient compared to the above systems and still makes the individual cooling compartments of the cabinet largely individually adjustable in their temperature, is in the German patent application DE 44 33 712 A1 described. Here are in the refrigeration cycle several evaporators in series, which are associated along the flow direction of the refrigerant a freezer, a cold storage compartment and a normal refrigeration compartment. To individually cool the individual compartments of the refrigerator, the amount of cold introduced into the chain of evaporators is controlled specifically. Then, if only the first located behind the condenser evaporator of the freezer compartment to be cooled, the refrigerant circuit is withdrawn refrigerant and stored in a reservoir cached. This leads to a depletion of refrigerant in the evaporator chain, so that cooling no longer takes place in the downstream evaporator of the standard refrigeration compartment. However, if this normal refrigeration compartment is to be cooled, the refrigerant flow coming from the condenser is guided through the reservoir by deflection of the cooling circuit, so that an increased amount of refrigerant flows from it into the evaporator. By means of this controlled by a solenoid valve deflection mechanism in the refrigeration cycle, the amount of refrigerant available can be controlled with minimal energy consumption and at the same time the condenser produce even with low demand for refrigerant this unhindered for storage in the reservoir and caching. Again, the switched refrigerant line through the reservoir or past this leads to increased costs in the production of refrigerated cabinets.

The object of the invention is to cost a To find cheap refrigerated cabinets with at least two thermally separated compartments and a suitable method for operating this cabinet, in which a subject-specific temperature control using only a single common refrigeration cycle and given a uniform, modular production of the evaporator components is possible.

The Task is performed by a refrigerated cabinet and a suitable for the operation of this refrigerator Method with the features of claims 1 and 8 solved. advantageous Embodiments and developments of the invention are characterized by the under claims described.

at the refrigerator with is at least two thermally separated compartments each of these subjects associated with an evaporator. Here are an expansion valve and these evaporators in a refrigerant circuit connected in series. In an inventive way are here at the expansion valve at least two states with different non-vanishing Flow coefficient adjustable. By non-disappearing be understood that in none of the at least two states of Flow through the expansion valve is interrupted.

The Invention is thus based on a targeted change in the flow coefficient an expansion valve in the refrigerant circuit a refrigerated cabinet. Herewith let yourself the refrigerant flow targeted by the evaporator of the refrigerator change. In a refrigerator with Single cycle causes this to change the ratio from liquid to gaseous refrigerant in the individual evaporators and thus a change in the evaporators available Cooling capacity.

Out the variability thus achieved the cooling capacity it turns out that the dimensions of each evaporator are not more, as before with refrigerators usual in series connected evaporators, by the expected relationship in the individual subjects required cooling capacity is determined. The evaporators can therefore, in terms of optimum energy efficiency, large format be measured.

The Advantages of the invention are particularly useful in multi-zone refrigeration appliances Wear, where individual subjects such as freezer, normal refrigerator, Basement compartment and / or 0 ° compartment individually and actively regulated.

There The evaporators of the refrigerator through the invention independently from the refrigeration requirement in the individual subjects free design / dimensioning, opens up the profit Potential to produce multi-zone refrigeration furniture, their components (in particular evaporators) uniform (modular) in big quantity can be used and Here are the advantages of the known from the prior art refrigerating furniture in terms Energy efficiency and controllability of the subjects opened.

It is in the production of the evaporator for the individual cooling compartments of the Cooling furniture here not necessary to use these as individual, individual components finished and for mounting on the refrigerator disposal to deliver. It is rather particularly advantageous, the individual Evaporator on a common carrier form and so on fast and inexpensive to create buildable evaporator module.

Around a targeted control or regulation of the refrigerant flow through the To allow evaporators It is conceivable on the one hand to design the expansion valve in such a way, that its flow coefficient is infinitely adjustable. On the other hand it is very possible, to carry out the expansion valve with switchable discrete flow coefficients. A Such discrete switchability is particularly useful in embodiments of refrigerators, which have few thermally separated compartments.

Around the temperature in the refrigerator especially to be able to regulate advantageously is it possible the thermally separated compartments of the refrigerator furniture temperature sensor assign. Here are these temperature sensors with an evaluation circuit for signaling a refrigeration demand in the individual subjects in conjunction, this evaluation circuit being part of a temperature control forms. If this temperature control via one of the temperature sensor in at least one of the subjects of the refrigerator cooling demand is signaled by this, the flow coefficient of the expansion valve adjusted so that the refrigerant flowing through it is preferably in that Compartment evaporates in which the refrigeration needs was recorded.

Further Features and advantages of the invention will become apparent from the following Description of exemplary embodiments with reference to the attached Characters. Show it:

1 a refrigerator with an expansion valve according to the present invention,

2 possible embodiments of an insertable in the refrigerator, three-stage switchable expansion valve.

In the in the 1 exemplified embodiment shown a refrigeration unit was used with only two subjects to simplify the presentation. Of course, limited the invention is not limited to such an embodiment, but can be transferred by expert action thereof on refrigerated cabinets with any number of subjects.

The 1 shows a refrigerated cabinet 20 which two subjects 21 . 21 ' which are to be regulated to different temperature. Each of the subjects 21 . 21 ' is an evaporator 2 . 2 ' assigned. This evaporator 2 . 2 ' lie in a refrigerant circuit through which refrigerant flows 1 in series behind a compressor 3 , a liquefier 4 and an expansion valve 5 ,

Each of the subjects 21 . 21 ' is a temperature sensor 12 . 12 ' assigned. These temperature sensors 12 . 12 ' stand with an evaluation circuit 11 for signaling a refrigeration demand in connection, which is part of a temperature control 10 forms. In known manner, the temperature control switches 10 via a control line 14 the compressor 3 when refrigeration demand is detected in one of the compartments and off again when no more refrigeration demand is detected. In addition, the temperature control controls 10 in the signaling of a refrigeration demand in at least one compartment 12 . 12 ' via a control line 13 the expansion valve 5 to adjust its flow coefficient depending on the detected refrigeration demand.

As long as in none of the subjects 21 . 21 ' There is a need for refrigeration and, consequently, the compressor 3 is turned off, the expansion valve 5 through the temperature control 10 kept closed. By thus preventing the pressure equalization between condenser caused 4 and evaporator 5 during the service life of the compressor 3 Depending on the design of the refrigerant circuit, energy savings of around 3% -10% can be achieved.

In case of large refrigeration demand in the short term, a larger amount of liquid refrigerant in the evaporator 2 . 2 ' it is an advantage to be able to bring in the cooling circuit 1 a condenser 4 downstream reservoir 6 To bring in, which serves to receive liquid refrigerant. From this, if necessary, for example, by heating the reservoir 6 , in the short term additional refrigerant be introduced into the cooling circuit.

If in one of the subjects 21 . 21 ' Refrigeration demand is detected, represents a simple embodiment, the temperature control 10 at the expansion valve 5 one of two discrete non-vanishing values of the flow coefficient, namely a low refrigeration requirement in the compartment 21 ' and a high value for refrigeration demand in the tray 21 ,

When the passage coefficient of the expansion valve 5 through the temperature control 10 is set small, is through the compressor 3 from the evaporators 2 . 2 ' sucked more refrigerant than through the expansion valve 5 in the evaporator 2 . 2 ' is introduced. The pressure in the evaporators is low, the evaporation temperature accordingly low. In this way, the refrigerant evaporates only near its exit point from the expansion valve 5 , in the evaporator 2 ' and it essentially becomes just the subject 21 ' cooled.

When the refrigeration needs in the from the expansion valve 5 along the flow path of the refrigerant more distant evaporator 2 is, the transmission coefficient of the expansion valve 5 through the temperature control 10 chosen big. Because through the compressor 3 less refrigerant is drawn off than via the expansion valve 5 in the evaporator 2 . 2 ' is introduced, the pressure in the evaporators and, accordingly, the boiling point of the refrigerant increases. If it is higher than the temperature of the compartment 21 ' , the refrigerant passes through the evaporator 2 ' without evaporating, and evaporates first in the evaporator 2 the warmer compartment 21 , In this way, essentially only the tray becomes 21 ' cooled.

An average transmission coefficient can be chosen when in both compartments 21 . 21 ' There is also a need for refrigeration. Then each part of the refrigerant evaporates in the evaporator 21 ' and the rest in the evaporator 21 ,

The same average transmission coefficient can be selected when the compartment 21 ' has an unusually high demand for refrigeration, such as the rapid freezing of newly stored refrigerated goods.

one not shown embodiment, a refrigerator has three or more through fans connected in series, and a the evaporators in a refrigerant circuit upstream expansion valve is between at least as many Values of the pass coefficient are switchable as fans exist are. The values are each chosen so that when setting a of these values the evaporation of the refrigerant predominantly in one of these Value assigned evaporator takes place. The value assigned to an evaporator the passage coefficient is higher, the farther downstream the associated evaporator in the refrigerant circuit lies.

In order to set the required different values of the transmission coefficient, an expansion valve with continuously variable transmission coefficient can be used. Particularly simple and sufficient for most applications are expansion valves, where only a small number of discrete values of the transmission coefficient set are bar.

In the case of in 1 sketched cooling cabinet 20 , which only has two compartments to be cooled 21 . 21 ' it is sufficient if two different non-vanishing transmission coefficients of the expansion valve 5 are adjustable. In this way, a very cost-effective temperature control can be realized profitably.

In the 2 Three possible embodiments for this purpose suitable expansion valve 5 demonstrated. All embodiments are equal to the splitting (for example by means of T-piece) of the main line 31 of the refrigerant circuit at the inlet to the expansion valve 5 in two parallel pathways. After this splitting, these two conduction paths become a blocking element 30 fed. This locking member 30 , z. B. a directional control valve, has a first switching stage, in which both conduction paths are shut off, a second switching stage, in which one of the two conduction paths open and the other is shut off, and a third switching stage, in which the other conduction path is open, wherein the a conduction path in this third switching stage may be open or disabled. At the output of the blocking member 30 there is a capillary tube 34 , in a conventional manner directly into the evaporator 21 ' empties.

When in the 2a ) sketched exemplary embodiment of the expansion valve 5 For example, the above-mentioned parallel conductive paths include the inputs of the blocking member 30 upstream capillary tubes 32 . 33 of different length and cross section. Depending on the switching stage of the blocking element 30 the refrigerant flows through the capillary tube 32 , the capillary tube 33 or by both in parallel, resulting in each case different flow coefficients of the expansion valve 5 result.

The same effect is when in the 2 B ) sketched embodiment of the expansion valve 5 by using capillary tubes 42 . 43 with different cross sections.

In the in the 2c ) expansion valve is on only one of the two line branches a capillary tube 52 intended; the other line branch 53 has no significant flow resistance due to its short length or large cross-section. Turns the locking member 30 his passage on the line branch 53 , this corresponds to a direct switching through the main line 31 on the at the output of the locking member 30 located capillary tube 34 , The line branch 53 thus forms a bypass around the capillary tube 52 ,

Of course, the design of a multi-stage controllable expansion valve is not on in the 2 limited embodiments shown. Instead of the capillary tubes, orifices can be used in an otherwise spacious refrigerant line. More than two non-zero values of the flow coefficient can be realized by providing a four-position directional valve, corresponding to the four possible combinations of "open" and "locked" of the two branches, or by the main line 31 in the expansion valve 5 is split into more than two parallel, individually switchable line branches.

Claims (11)

Refrigerated furniture ( 20 ) with at least two thermally separated compartments ( 21 . 21 ' ), whereby each of the subjects ( 21 . 21 ' ) an evaporator ( 2 . 2 ' ), in which an expansion valve and these evaporators ( 2 . 2 ' ) in a refrigerant circuit through which refrigerant flows ( 1 ) are connected in series, characterized in that on the expansion valve at least two states with different non-vanishing flow coefficients are adjustable. Refrigerator according to claim 1, characterized in that the flow coefficient of the expansion valve ( 5 ) is infinitely adjustable. Refrigerator according to claim 1, characterized in that the expansion valve ( 5 ) is switchable between discrete values of the flow coefficient. Refrigerator according to claim 3, characterized in that the expansion valve has two parallel pipe sections ( 32 . 33 . 42 . 43 . 52 . 53 ) and a blocking member ( 30 ) for shutting off one of the two line sections in one of the two states. Refrigerator according to one of the preceding claims, characterized in that on the expansion valve ( 5 Further, a third state is adjustable, in which it is impermeable to the refrigerant. Refrigerator according to one of the preceding claims, characterized in that the evaporators ( 2 . 2 ' ) are formed on a common carrier. Refrigerator according to one of the preceding claims, characterized in that in the refrigeration circuit ( 1 ) the liquefier ( 4 ) downstream reservoir ( 6 ), which serves to accommodate or intermediate storage of liquid refrigerant. Refrigerated furniture according to one of the preceding Patent claims, characterized in that the thermally separated compartments each have a temperature sensor ( 12 . 12 ' ), these temperature sensors ( 12 . 12 ' ) with an evaluation circuit ( 11 ) are associated with signaling a refrigeration demand which is part of a temperature control ( 10 ). Method of operating a refrigerated cabinet ( 20 ) with at least two thermally separated compartments ( 21 . 21 ' ), in particular according to one of the claims 1 to 8th in which refrigeration requirements in the subjects ( 21 . 21 ' ) of the refrigerated cabinet ( 20 ) and the supply of refrigeration to the subjects ( 21 . 21 ' ) and connected in series evaporators ( 2 . 2 ' ) is controlled with liquid refrigerant in dependence on the refrigeration demand, characterized in that the control of the refrigerant supply by adjusting at least two states with different non-vanishing flow coefficients in a controllable expansion valve ( 5 ), the state being selected according to which of the subjects ( 21 . 21 ' ) the refrigeration demand is detected. A method according to claim 9, characterized in that when detecting refrigeration demand in a compartment, the evaporator is far away from the expansion valve, a high flow coefficient of the expansion valve ( 5 ) and when refrigeration demand is detected in a compartment whose evaporator is close to the expansion valve ( 5 ), a low flow coefficient of the expansion valve ( 5 ) is set. Method according to claim 9 or 10, characterized in that, if in none of the compartments ( 21 . 21 ' ) of the refrigerated cabinet ( 20 ) is a refrigeration demand, the expansion valve ( 5 ) is kept closed.