DE10358944A1 - Compressor refrigeration circuit for air conditioning systems has absorption and dissipation units operating at different refrigerant pressures - Google Patents

Abstract

The refrigeration circuit (10) has a compressor (20), a heat dissipation condenser (60), a liquid receiver (90) and an expansion valve (30) cooling an evaporator (100) creating a high pressure side (40) and a low pressure side (50) providing cooling for operational equipment and vehicle interiors.

Description

The invention relates to a refrigerant circuit with heat receivers and heat transmitters and a refrigeration system with a refrigerant circuit.

Such refrigerant circuits are in refrigeration systems, such as air conditioners, used to heat from at least a first spatial Area in at least a second spatial area, in particular with compared to the first spatial Range equal or higher temperature level, to transport. The refrigerant is taking in one as a heat absorber operated heat exchanger in the first spatial Area heat on, becomes a heat dissipator operated Heat exchanger in the second spatial Area headed to heat there leave.

To a heat transfer from a relatively colder a relatively warmer one spatial To enable area the refrigerant is usually in a relaxed state, so at lowered temperature, through the heat absorber and in a compacted state, ie at elevated temperature, through the heat emitter directed. Included for this purpose the refrigerant circuit a compression element, such as a compressor, and a relaxation element, such as an expansion valve, so that refrigerant the cycle in the order of compression element - heat dissipator - expansion element - heat absorber flows through.

As heat dissipators often become capacitors used in which the refrigerant with release of heat energy condenses, where "yourself the temperature of the refrigerant while of the phase transition Condensation changes only insignificantly. In a similar way become common so-called refrigerant evaporator as a heat absorber used in which the refrigerant is evaporated, wherein the temperature of the refrigerant during the Phase transition Evaporation also only slightly changes. But refrigerant circuits, however partly without phase transitions of the refrigerant be operated, the terms "condenser" and "evaporator" are partly misleading and should not be used here except for specific examples.

The temperature levels of a refrigerant circuit hang for a given refrigerant mainly from the pressure levels, being on the high pressure side of the circuit, So in the flow direction of the refrigerant after the compression element, in principle, higher temperatures prevail as on the low pressure side after the expansion element. Should now several heat absorbers in a refrigerant circuit are used, the pressure conditions on the low pressure side the circulation to the heat absorber with the lowest desired Adjust operating temperature, as this heat absorber at higher temperatures not enough Thermal energy could take up. Is with another heat absorber a higher one Temperature desired or sufficiently, it is thermodynamically uneconomical to do this further heat absorber operate at a low temperature. The appropriate consideration applies analogously for Heat emitter.

It is therefore an object of the invention a refrigerant circuit and / or a refrigeration system to provide multiple heat receivers and / or more heat emitter are each operable at different temperatures.

This task is performed by a refrigerant circuit with the features of claim 1 and by a refrigeration system solved with the features of claim 16.

According to claim 1, a refrigerant circuit at least one heat absorber, in the heat from a refrigerant is receivable, and at least one heat emitter, in the heat of the refrigerant is deliverable, up. The object of the invention is characterized advantageous solved, that several functionally identical heat exchangers, So several heat absorbers or more heat dissipaters, at different refrigerant pressure are operable. This is the basic idea of the invention, namely the Operating temperatures of several functionally identical heat exchanger to adapt to different requirements, in a simple way realizable.

As functionally identical heat exchanger are in the context of the present invention, such heat exchangers to look at during an operation of the refrigerant circuit simultaneously perform the same function, so either a heat transfer from a medium to the refrigerant or from the refrigerant on a medium. As a medium, for example, comes a liquid, gaseous, supercritical or any other fluid as well as, for example a solid or a particular heat-generating Device or combinations thereof. The functional equality two heat exchangers will not be touched by possibly different functions, two or more Heat exchanger at different times, for example, in different operating modes of the refrigerant circuit.

Refrigerant pressure levels are different in the context of the present invention, when the difference between the pressure levels of the individual levels is greater than a pressure drop, which usually occurs, for example, along refrigerant lines or heat exchangers. In particular, two hydraulic heat exchangers connected directly one after the other are not operable at different refrigerant pressure levels, as long as no conveying or throttling means are provided for the refrigerant in or between the two heat exchangers. A through a compression element or by a relaxation On the other hand, the pressure difference produced by the element is very well suited to produce two different refrigerant pressure levels within the scope of the invention.

As a compacting element, each Apparatus which is suitable for transporting refrigerant from a location of a Circulation to another location of the circuit with higher pressure to promote, that means refrigerant to condense. Compressors and pumps are examples of compaction elements.

As a relaxation element, each Device, which is suitable for a pressure drop between a location of a refrigerant circuit and another place of the cycle, ie refrigerant to relax. Externally controllable and non-controllable expansion valves and chokes are examples of Relaxation elements, with each bottleneck in the refrigerant circuit, for example, a small diameter tube between two heat exchangers, optionally suitable as a throttle. For a desired, that is in this Throttling suitable as a throttle bottleneck may be a in half reduced flow diameter sufficient.

To achieve a compact design is it is advantageous, a compression element and / or a relaxation element with a heat exchanger structurally to unite. For example, a throttle is simple Way in a heat exchanger integrated. Indicates a heat exchanger several hydraulically cascaded flow paths on, so is one in the heat exchanger integrated throttle also by a reduced number of particular the first or last flow path of the heat exchanger forming, hydraulically parallel flow channels feasible.

According to an advantageous embodiment a first heat absorber, a second heat absorber and a heat dissipator Operable at three different pressure levels, the first heat absorber at higher Pressure is operable as the second heat absorber. There are two different cooling temperature levels at independent of it Heat temperature guaranteed. In particular, the first and the second heat absorber are hydraulically parallel switched, each of the two heat receivers has its own relaxation element upstream and / or downstream, so that the heat absorber at different pressure levels with refrigerant can be acted upon. In certain circumstances it is sufficient if only the first or only the second heat absorber a relaxation element is upstream or downstream. In another embodiment are a first and a second heat absorber hydraulically in Series switched, with a pressure difference by an interposed Relaxation element is feasible.

According to a preferred embodiment a first heat absorber and a heat dissipator Operable at a common pressure level. This will add extra Compression and / or expansion elements and a related Saves production, assembly and Kostenauf wall. The operating temperature of the first heat absorber at least approximately the operating temperature of the heat emitter.

Particularly preferred is downstream of the first heat absorber a compensation element for the Refrigerant such as a collection container arranged in which optionally a filter element and / or a Dryer is receivable. The compensation element is essentially as structured as a customary one downstream of a heat dissipator Compensation element and serves a collection and possibly one Phase separation of the refrigerant, so that one Relaxation element only liquid refrigerant supplied becomes.

According to a preferred embodiment of the refrigerant circuit the first heat absorber is hydraulic between two sections of the heat emitter arranged. This means that refrigerant after flowing through a first section of the heat emitter through the first heat absorber passed and then in the heat dissipator is attributed where it is afterwards flows through a second section.

In one embodiment, while the entire Refrigerant flow through the first heat absorber guided. In a further embodiment is only part of the refrigerant flow through the first heat absorber guided, while another part of the refrigerant flow through a bypass connection from the first to the second section of the heat emitter. Particularly preferred the bypass connection a third section of the heat emitter, so that refrigerant after the first section either the first heat absorber or the third Section of the heat emitter and finally flows through the second section.

According to a preferred embodiment forms the first heat absorber with a section of the heat emitter a closed subcircuit.

The refrigerant then becomes a main circuit downstream the heat emitting section taken by the first heat absorber guided and the main circuit upstream the heat emitting section fed again. In particular contains the subcircuit a compression and a relaxation element, wherein For example, the compression element as a compression element the main circuit is used. Preferably, however, is the closed Partial circulation within a pressure level, that is none Compression or expansion elements are in the subcircuit contain.

According to an advantageous development, the first heat absorber is geodetically lower than arranged the heat emitting section of the partial circuit. Refrigerant, which absorbs heat in the first heat absorber, that is heated, rises up, enters the heat dissipation section, there to give off heat, so to be cooled, and to sink back down to the first heat absorber. For such a so-called natural circulation no compression element is needed, which is why this heat transfer takes place even when a compression element is either switched off or not present. It may therefore be possible to save energy or cooled or cooled. In order to support the natural circulation with regard to a flow resistance of the partial circuit, it is particularly preferable to provide an additional coolant delivery device, for example a liquid pump, with which a pressure drop along the refrigerant subcircuit can be compensated.

Another advantageous development used for maintaining a refrigerant flow in the subcircuit a suction, on which the first heat absorber communicates with the main circuit. The suction, for example, as so-called Venturi nozzle or similar is formed, while sucking refrigerant from the first heat absorber off and on it to the main cycle too. This also causes a pressure drop along of the refrigerant subcircuit compensated or overcompensated. Advantageously, the suction element is in a heat dissipator integrated.

According to a preferred embodiment of the refrigerant circuit according to the invention forms at least one heat absorber with at least one heat emitter a structural unit. Especially with the same or similar Refrigerant pressure levels and the same or similar Operating temperature levels is with such a combined component a simplified installation in a given space feasible.

According to another embodiment is at least a heat absorber additionally cooled. The means only a part of the absorbed heat energy transferred to the refrigerant and is transported away and a part directly to a cooling Medium such as passing air is discharged.

According to an advantageous embodiment is from at least one heat absorber, the especially at higher Refrigerant pressure as at least another heat absorber is operable, heat energy from a medium of a secondary Cycle, with the secondary cycle being particularly preferred a coolant circuit is. As a result, an indirect cooling of one or more heat-generating Components possible.

According to a preferred embodiment a first heat absorber as a cooler for electronic components educated. Particularly preferred is a second heat absorber as a cold producer an air conditioner, in particular for motor vehicles trained. Here, the idea of the invention becomes particularly noticeable because cold producer of air conditioners. usually be operated at significantly lower temperatures than Küh ler of electronic components. So it is especially beneficial in In this case, two heat absorbers operate at different pressure levels.

According to a preferred embodiment is the refrigerant circuit according to the invention in a refrigeration system used to create multiple components at different temperature levels to cool or to heat.

The invention will be described below of exemplary embodiments explained in more detail with reference to the drawings. Show it:

1 FIG. 1 is a schematic view of a refrigerant circuit according to the present invention; FIG.

2 - 8th in each case a schematic view of a refrigerant circuit and

9 : a schematic view of a secondary circuit.

In 1 is a refrigerant circuit 10 shown in a schematic view. A compaction element 20 and a relaxation element 30 limit a high pressure side 40 and a low pressure side 50 of the cycle 10 , Refrigerant thus flows, starting from the compression element 20 , counterclockwise through the circuit 10 , By a compression in the compression element 20 , which is formed for example as a compressor, the temperature of the refrigerant increases, whereupon heat of the refrigerant in a heat emitter 60 on by arrows 70 indicated, passing air is discharged.

Subsequently, the refrigerant flows through a first heat absorber 80 in that it receives heat from a component, not shown, to be cooled, such as an electronic control device or the like. Thereafter, the refrigerant is in a surge tank or reservoir 90 caught and the relaxation element 30 fed where it is in the low pressure side 50 entry.

By the relaxation in the expansion element, the temperature of the refrigerant decreases significantly, so that in a second heat absorber 100 receiving another thermal energy, not shown, such as an air stream or the like, can be cooled. The cooling temperature of the low-pressure side heat absorber 100 cooled component is significantly lower than the cooling temperature of the high-pressure side heat absorber 80 cooled component, since the heat absorber is operable at the pressure level of the heat emitter. By forwarding the refrigerant to the compression element 20 becomes the refrigerant circuit 10 closed.

Is the refrigerant circuit 10 operated with a two-phase refrigerant, such as R134a, is the difference in temperature levels on the high pressure side 40 or on the low-pressure side 50 particularly pronounced. In a design of the circuit 10 for common air conditioners, the temperature of the two-phase region of the refrigerant on the high pressure side is usually in the range of 40 ° C to 70 ° C, on the low pressure side, however, in the range of 0 ° C. The then operated as an evaporator heat absorber 100 on the low pressure side is suitable for the cooling of air for air conditioning a room, such as an interior in a motor vehicle, and the heat absorber 80 on the high pressure side is adapted to a preferred cooling temperature of electronic components such as control units and the like. That in the relaxation element 30 expanded refrigerant is therefore in the evaporator 100 evaporated, in the compressor 20 compressed, then effective as a capacitor heat dissipator 60 condenses, in Wärmeaufneh mer 80 at least partially re-evaporated and / or heated and finally in the compensating element 90 collected where the gaseous fraction is deposited.

2 shows a refrigerant circuit 110 with a compression element 120 , a heat emitter 130 , a first heat absorber 140 , a compensation element 150 , a relaxation element 160 and a second heat absorber 170 , Refrigerant flows through a first section 180 of the heat emitter 130 , then through the first heat absorber 170 and then through a second section 190 of the heat emitter 130 , The first heat absorber 170 is traversed by the entire refrigerant.

Is the desired cooling temperature of the first heat absorber 140 lower than the operating temperature of the heat emitter 130 , The pressure level of the first heat absorber and thus the second section 190 of the heat emitter 130 optionally with the help of a relaxation element 200 lowered. The relaxation element 200 is formed in the simplest case as a throttle through a small opening through which the refrigerant must pass, wherein the opening, for example, in a partition wall of a collecting tank of the heat emitter 130 can be arranged. In a heat dissipator with serpentine-like interconnected heat exchanger tubes, it is possible, the throttling effect by a reduced number of tubes or channels of multi-chamber tubes, ie by a reduced flow cross-section, in a. Serpentine section, in particular in the last serpentine section of the first heat dissipation section 180 , to realize. It is also possible, an externally controllable expansion valve as a relaxation element 200 use, whereby the operating temperature of the first heat absorber 140 can be adapted to time varying requirements.

In a similar embodiment, which is not shown, forms the compensating element, for example, designed as a collecting container and optionally equipped with a filter and / or dryer unit with the heat emitter a structural unit, wherein the refrigerant after flowing through the compensating element by a so-called subcooling of the Heat emitter is performed. This variation, which is also possible in principle in the other embodiments listed, without departing from the scope of the present invention, allows a subsequent connection of the first heat absorber and the compensation element, so that the second section 190 of the heat emitter 130 from the previous example ( 2 ) forms the subcooling section of the unit of heat dissipator and compensating element.

In the refrigerant circuit 210 in 3 becomes a first heat absorber 220 only part of it 230 the refrigerant flow detected, whereas another part 240 of the refrigerant flow through a third section 250 of the heat emitter 260 flows, the third section 250 between a first section 270 and a second section 280 of the heat emitter 260 is arranged. From the compression element 290 Coming refrigerant thus flows through the first section 270 of the heat emitter 260 , then goes to the third section 250 and the first heat absorber 220 split and then in the third section 280 of the heat emitter 260 reunited. Subsequently, the refrigerant is again in a compensation element 300 collected so that optionally a gaseous portion of the refrigerant can be deposited.

The refrigerant circuit 310 in 4 is different from that 3 known cycle 210 in principle in that the first heat absorber 320 geodetically lower than the heat dissipator 360 , in particular as its middle section 350 with which the first heat absorber forms a closed partial circuit. This will, as in the refrigerant circuit 410 in 5 shown, a heat transfer from the first heat absorber 420 to the heat emitter 460 or its middle section 450 even when the compression element is switched off 490 allows.

Such a natural circulation cooling is self-evident, since the refrigerant is absorbed by a heat in the first heat absorber 420 heated and / or optionally partially evaporated, rises and in the middle section 450 of the heat emitter 460 cooled again and / or optionally condensed, after which the refrigerant drops again and reaches the first heat absorber. The transported heat energy is doing, for example, to an air flow 470 issued. A cooling effect of the first heat absorber 420 So it remains even when the compression element is switched off 490 , as in the winter operation of an air conditioner received. The associated saving of energy is evident. Compared to a summer operation of the refrigerant circuit 310 ( 4 ) with the compression element switched on 390 has the flow direction of the refrigerant through the first heat absorber 420 but vice versa.

In another, not shown embodiment the natural circulation through a small refrigerant conveying device, such as a liquid pump, support the. Refrigerant conveyor be arranged either before or after the first heat absorber can.

6 represents another refrigerant circuit 510 with one from a first section 520 and a second section 530 existing heat dissipator 540 in which a first heat absorber 550 with the second section 530 of the heat emitter 540 forms a closed circuit. To return the refrigerant from the first heat absorber 550 to promote, communicates the first heat absorber 550 via a suction element 560 with the heat emitter 540 , wherein the suction element 560 For example, is designed as a so-called venturi nozzle, in which by means of passing refrigerant within the heat emitter 540 the pressure in the first heat absorber 550 coming line 570 is lowered.

7 shows a refrigerant circuit 610 with a suction element 660 , Unlike the cycle 510 in 6 in which the suction element 560 between the two sections 520 and 530 in the heat dissipator 540 is integrated, is the suction 660 between the compression element 680 and the heat emitter 640 arranged. As in 6 the flow direction of the refrigerant is also in 7 indicated by arrows.

In 8th is another variant of a refrigerant circuit 710 shown in which a high pressure side 720 and a low pressure side 730 through a compression element 740 and two relaxation elements 750 . 760 are separated from each other. One of a first heat absorber 770 and a section 780 a heat dissipator 790 formed partial cycle 800 extends to both sides 720 . 730 , In the subcircuit 800 the refrigerant is removed from the first heat absorber 770 by the example designed as a throttle expansion element 750 in the low pressure side 730 discharged to finally from the compacting element 740 compressed and the heat dissipator 790 to be fed. In the heat dissipator 790 divides the refrigerant on the subcircuit 800 and a main circuit 810 of the refrigerant circuit 710 on. A second section 82o of the heat emitter 790 , a compensation element 830 , the relaxation element 760 and a second heat absorber 840 on the low pressure side 730 are in the main circuit 810 ,

In a similar embodiment is located in the partial circuit 800 between the heat emitter 790 and the first heat absorber 770 another relaxation element, so that the pressure. and / or the temperature of the heat absorber 770 opposite the heat emitter 790 if necessary to a reduced level.

In another embodiment, the second section is omitted 820 of the heat emitter 790 , so that the branch point of the subcircuit 800 from the main circuit 810 hydraulically between the heat emitter 790 and the relaxation element 760 and before or after the compensation element 830 is arranged.

9 represents a section of a refrigerant circuit 910 according to the present invention. A heat absorber 920 is on a high pressure side of the refrigerant circuit 910 arranged to heat energy from a secondary cooling circuit 930 take. The secondary cooling circuit 930 serves a heat transfer of several in series or parallel to each other connected components 940 . 950 and 960 to the heat exchanger 920 from the point of view of the cooling circuit 930 a heat dissipator. A coolant circulation through the cooling circuit 930 is through a compression element 970 ensures, for example, is designed as a coolant pump. The components to be cooled 940 . 950 and 960 For example, electronic assemblies or controls or other heat generating devices.

Claims (16)

Refrigerant circuit with at least one heat absorber and at least one heat emitter, characterized in that a plurality of functionally identical heat exchanger can be operated simultaneously at different refrigerant pressure. Refrigerant circulation according to claim 1, characterized in that each refrigerant connection between two operable at different pressure heat exchangers at least one compression element and / or at least one expansion element. Refrigerant circulation according to claim 2, characterized in that at least one compression element and / or at least one expansion element with a heat exchanger forms a structural unit. Refrigerant circuit according to one of the preceding claims; characterized in that a first heat absorber, a second heat absorber and a heat emitter are operable at three different pressure levels. Refrigerant circulation according to one of the preceding claims, characterized the existence first heat absorber and a heat emitter a common or similar Pressure level are operable. Refrigerant circulation according to claim 5, characterized in that a compensating element, in in particular the refrigerant filterable and / or the refrigerant Water is drainable, downstream of the first heat absorber is arranged. Refrigerant circulation according to claim 5 or 6, characterized in that the first heat absorber is arranged hydraulically between two sections of the heat emitter. Refrigerant circulation according to claim 7, characterized in that the two sections via a bypass connection communicate with each other, the bypass connection in particular a third section of the heat emitter includes. Käliemittelkreislauf according to one of claims 5 to 8, characterized in that the first heat absorber with a section of the heat emitter a closed subcircuit, in particular within a Pressure levels, forms. Refrigerant circulation according to claim 9, characterized in that the first heat absorber geodesic lower than the heat dissipation section is arranged. Refrigerant circulation according to claim 9 or 10, characterized in that the first Heat absorber over a Suction element communicates with a main circuit, wherein the suction element in particular in a heat dissipator is integrable. Refrigerant circulation according to one of the preceding claims, characterized that at least a heat absorber with at least one heat emitter forming a structural unit. Refrigerant circulation according to one of the preceding claims, characterized that at least a heat absorber additionally is coolable, especially with overflowing Air. Refrigerant circulation according to one of the preceding claims, characterized that of at least one heat absorber Thermal energy a secondary one Cycle, in particular cooling circuit, is receivable. Refrigerant circulation according to one of the preceding claims, characterized the existence first heat absorber a cooler for electronic Components and in particular a second heat absorber a cold generator an air conditioner is. Refrigeration system, especially air conditioning for one Motor vehicle, with a refrigerant circuit, which is designed according to one of the preceding claims.