Receiver and heat pump

Abstract

A collector (10) for a refrigerant circuit, comprising a sump (12) collecting the condensed refrigerant as the bottom part (12) of a collector housing (11) which has a cover part (13) and with pipes for the refrigerant inlet and outlet, according to the invention comprises at least one, preferably both, of the following features: a) a medium-pressure connection (17) for intermediate injection of refrigerant from the collector into the compressor is provided in the upper region of the collector housing (11) and comprises a pipe part (18) that projects into the interior of the collector housing (11) and whose free end lies below the cover part (13) at a distance from it, b) an additional heat exchanger (20) that is arranged in the lower part of the collector housing (11).

Description

[0001] The invention relates to a collector for a refrigerant circuit and a heat pump with a collector in its refrigerant circuit.

[0002] In a refrigerant circuit, refrigerant is compressed, passed through a condensing heat exchanger, and condensed, before being passed through another evaporating heat exchanger, where the refrigerant evaporates. The refrigerant is then recompressed, and the process described above begins again. To optimize the refrigerant circuit or this process under varying boundary conditions, buffer vessels are installed to temporarily store unused refrigerant and feed it back into the refrigerant circuit when needed. If such a buffer vessel is installed on the high-pressure side of a refrigerant circuit after the condenser, the buffer vessel is called a receiver.

[0003] A refrigerant circuit of the type mentioned above must regularly be operated in two directions for various reasons. In one direction, the refrigerant circuit runs in heating mode and in the opposite direction, called reverse operation, in cooling mode. If a receiver is installed in such a refrigerant circuit, it is usually designed so that flow always occurs in one direction, despite the reversal of the refrigerant circuit direction, for example, by using check valves and combinations thereof or similar components. Alternatively, the receivers can be bypassed for individual operating directions, for example, by a bypass line. If the receiver can accept flow in both directions, it is called a "bi-flow receiver."

[0004] Particularly when operating as a "bi-flow receiver," it is advantageous if the receiver housing allows a large distance between the inlet and outlet pipes to allow the refrigerant to settle in the receiver. In particular, bubbles present in the condensed refrigerant should be removed from the receiver so that only liquid refrigerant is introduced into the refrigerant circuit at the receiver outlet. This is necessary for the operational reliability of the expansion valve. To accommodate the large spacing between the pipes, state-of-the-art receivers have a relatively large diameter. Due to this large diameter of the receiver, a correspondingly large amount of refrigerant must be stored in the receiver sump, which is considered disadvantageous, especially with flammable refrigerants.

[0005] For environmental reasons, it is also desirable to implement a refrigerant circuit with the smallest possible amount of refrigerant.

[0006] To create a receiver with the smallest possible receiver volume, DE 10 2022 134 307.3 specifies that the receiver incorporates receiver tubes designed as risers. The risers extend through the housing interior into the receiver sump in the base section. The risers therefore only end in the sump, where the condensed refrigerant is collected. The outlets of the risers are positioned at a very short distance from the base plate of the sump and thus from the base plate of the base section of the receiver housing.

[0007] Based on this collector, the invention is based on the task of optimizing its refrigeration circuit.

[0008] This object is achieved by the subject matter of claims 1 and 10. The dependent claims relate to expedient and inventive developments of this invention.

[0009] According to the invention, the collector has two independent aspects, which can be realized alternatively or jointly, namely: 1st aspect: The collector has a medium-pressure connection for intermediate injection of refrigerant into the compressor in the upper area of ​​the collector housing. This connection comprises a pipe section that protrudes into the interior of the collector housing and whose free end lies below the cover part at a distance from the cover part. 2nd aspect: The collector has an integrated second heat exchanger located in the lower part of the collector housing.

[0010] The medium-pressure connection according to the first aspect of the invention is arranged either laterally in the wall of the collector housing or in the cover part of the collector housing. The exact position of this connection is not critical. What is important, however, is the position of the free pipe end of the connection. This end should be located in the area of ​​the cover part of the collector housing close to the cover part, but in such a way that the inflow of refrigerant is not impaired by the cover part. If the connection is arranged close to the cover part below it, the pipe part can have a straight course, since in this cover part position the free pipe end is close enough to, but sufficiently far away from, the cover part. If the connection is positioned further away from the cover part, at least the free pipe end is bent or curved upwards towards the cover part.If the connection is arranged in the cover part, its pipe part preferably extends a short distance downwards towards the bottom part of the collector housing.

[0011] In the collector housing, a partition wall, preferably in the form of a partition plate, is provided below the pipe part of the medium-pressure connection, which divides the interior of the collector housing into an upper and a lower area in order to increase the operational reliability of the collector and to provide flow calming.

[0012] The additional integrated heat exchanger according to the second aspect of the invention contributes to the optimization of the refrigeration circuit through its heat transfer. The additional integrated heat exchanger transfers heat, in particular, from the liquid refrigerant inside the receiver to the suction gas of the compressor. The additional integrated heat exchanger can be constructed in various ways, for example, as a coiled-tube heat exchanger or another known design. The principle and mode of operation always remain the same.

[0013] According to the invention, the additional heat exchanger comprises a refrigerant inlet and a refrigerant outlet, which preferably extend laterally through the collector housing. The additional heat exchanger is preferably arranged in the lower region of the collector. The multiply folded or serpentine tube of the heat exchanger is a smooth tube, an internally finned tube, or an externally finned tube. The tube can also be internally and externally finned.

[0014] Advantageously, the pipes for the refrigerant inlet and the refrigerant outlet of the additional heat exchanger and / or the collector are designed as riser pipes which pass through the collector housing in its housing interior from the cover part into the sump and that a flow calming agent is arranged between the riser pipes in the region of the sump.

[0015] The riser pipe connections to the refrigerant circuit are located on the cover of the collector housing. Alternatively, the riser pipes can also exit the collector housing from the side.

[0016] Condensed refrigerant, in particular, enters the collector in liquid form and is stored there. The liquid refrigerant can, of course, also contain gas bubbles, and it is precisely these gas bubbles that collect at the top of the collector according to the invention.

[0017] To smooth the flow between the riser pipes near their ends, the collector incorporates a flow-smoothing device. In one design, a partition wall is arranged between the riser pipes near the sump. The partition wall also extends into the refrigerant-filled sump, effectively dividing the sump into two parts. The partition wall smooths the flow of refrigerant flowing into the collector from one of the riser pipes. Because the ends of the riser pipes are so close to the base plate of the collector housing, a comparatively small amount of refrigerant is sufficient to fill the collector sump with refrigerant.

[0018] The partition wall that divides the sump into two parts ensures that the flow of the refrigerant is calmed, so that the sump acts like a cooling pond for the incoming refrigerant. In particular, existing bubbles are effectively removed from the refrigerant in this way.

[0019] Alternatively or additionally, the pipe ends of the riser pipes extending into the sump are specially designed to provide flow calming agents.

[0020] For this purpose, the pipe ends are beveled in an advantageous embodiment. In particular, the bevel of the pipe end(s) is designed such that the flow of the refrigerant entering through the riser pipes is deflected away from the respective other riser pipe. Preferably, the riser pipes are beveled at an angle of 30° - 60°, in particular approximately and particularly preferably exactly 45°. Alternatively or in addition to a bevel, the riser pipes can be bent, which also achieves the flow-calming effect away from the respective other riser pipe.

[0021] In a further advantageous embodiment, the collector housing is constructed as at least a two-part, three-part, or multi-part housing. The collector housing initially comprises a bowl-like base part and a hood-like cover part. One or more shell parts are advantageously arranged between the base part and the cover part. In the final assembly state, the cover part, all optional shell parts, and the base part are firmly connected to one another, in particular welded together.

[0022] The receiver according to the invention can be operated bidirectionally as a "bi-flow receiver." Each of the riser pipes can thus be used as either an inlet pipe or an outlet pipe for the refrigerant mass flow.

[0023] Finally, the heat pump according to the invention uses a refrigerant circuit with the prescribed collector according to the invention.

[0024] The invention is explained in further detail using the exemplary embodiment shown in the drawing figures. They show: Fig. 1 is a longitudinal sectional view of an embodiment of a collector according to the first aspect of the invention with a medium pressure connection for an intermediate injection of refrigerant, which is provided in a wall of the collector housing. Fig. 2 is a longitudinal sectional view of a modified embodiment of a collector according to Fig. 1 Fig. 3 is a longitudinal sectional view of an embodiment of a collector according to the first aspect of the invention with a medium-pressure connection for an intermediate injection of refrigerant, which is provided in a cover part of the collector housing, and Fig. 4 is a longitudinal sectional view of an embodiment of a collector according to the second aspect of the invention with an additional heat exchanger, which is arranged in the lower part of the collector housing.

[0025] Identical and structurally identical parts are provided with identical reference numbers. The figures may contain simplified or schematic representations. Different views of identical parts may be scaled differently.

[0026] The Fig. 1 The collector 10 shown for a refrigerant circuit comprises a three- or multi-part generally cylindrical collector housing 11 with a refrigerant collecting sump as a bowl-like bottom part 12 and a hood-like cover part 13.

[0027] Pipes for the refrigerant inlet and outlet penetrate the ceiling section 13. These pipes are designed as riser pipes 14 and 15, which penetrate the entire interior of the collector housing 11 in the direction of its central longitudinal axis and extend to the sump in the base section 12 at a predetermined distance from the latter. Refrigerant flows into the base section 10 and thus the sump of the collector at the end of one riser pipe 14 facing the base section 12, partially or completely filling the base section 10. The liquid refrigerant that has escaped and, after settling in the associated sump chamber and freed of bubbles, flows along or up a baffle 16 that extends from the base section 12 to a predetermined height along the central axis of the collector housing 11. The separating plate 16 blocks a direct flow between the two riser pipes 14 and 15, so that the separating plate 16 acts as a flow calming agent.The refrigerant advantageously flows substantially or entirely laterally along the separating plate 16 and into the adjacent sump chamber. From this chamber, the refrigerant temporarily stored in the collector is reintroduced into the refrigerant circuit as needed through the associated riser pipe 15, which serves as the refrigerant outlet.

[0028] The pipe ends of the riser pipes 14 and 15 reinforce the flow-calming effect of the separating plate 16. The shape of the pipe ends prevents the refrigerant flowing through one riser pipe 14 from flowing directly to the other riser pipe 15. In the longitudinal section of the Fig. 1 The pipe ends of the riser pipes 14 and 15 have bevels to provide the flow-calming effect.

[0029] In order to optimise the refrigeration cycle, Fig. 1In the embodiment of the collector 10 shown, a medium-pressure connection 17 is provided as a source for an intermediate injection of refrigerant into the compressor of the refrigeration circuit in the upper region of the collector housing 11. The medium-pressure connection 17 comprises a pipe part 18 which projects into the interior of the collector housing 11 and whose free end lies below the cover part 13 at a distance from the latter. The pipe part 18 penetrates the cylindrical shell of the collector housing 11 and runs inside the same initially parallel to the base and cover parts 12, 13, before ending in an end section under a bend which extends obliquely upwards in the direction of the cover part 13.

[0030] The Fig. 2 The embodiment of the collector 10 shown differs from the embodiment in Fig. 1 by the fact that the medium pressure connection 17 is located closer to the cover part 13 and that its pipe part 18 is arranged after a shorter course than in Fig. 1 without kinks or bends into its end section. Furthermore, an optional separating plate 19 is provided below the level of the pipe section 18, which runs parallel to the base and cover sections 12, 13 and divides the interior of the collector container 11 into an upper area of ​​smaller volume and a lower area of ​​larger volume in order to increase the operational reliability of the collector. The separating plate 19 can also be used in the embodiment of the collector 10 of Fig. 1 The exact course of the medium-pressure connection 17 is of secondary importance, as long as the line ends near the upper dome of the collector 10, preferably at a distance of not less than 10% of the height of the collector 10 from its cover part 13.

[0031] The Fig. 3 The embodiment of the collector 10 shown differs from the embodiments in Fig. 1 and Fig. 2by the fact that the medium pressure connection 17 is provided in the cover part 13 between the two riser pipes 14 and 15. As in Fig. 2 the pipe part 18 extending parallel to the central axis of the collector housing 11 runs after a shorter course than in Fig. 1 kink-free into its end section. In this embodiment of the collector 10, the separating plate 19 is also Fig. 2 provided optionally.

[0032] In order to optimise the refrigeration circuit, alternatively to the embodiments of the collector 10 of Fig. 1 to Fig. 3 in the Fig. 4In the embodiment of the collector 10 shown, an integrated additional heat exchanger is provided, which is arranged in the lower part of the collector housing in the area of ​​the collector sump or in this. The additional heat exchanger 20 comprises the actual heat exchanger 21 with a refrigerant inlet 22 and a refrigerant outlet 23, which penetrate the collector housing 11 laterally into its casing. The folded or serpentine tube of the heat exchanger has one of the following features: the tube is designed as a smooth tube, as an internally finned tube, as an externally finned tube, or as a tube with both internal and external fins.

[0033] The independent measures to optimize the refrigeration circuit according to the Fig. 1 to Fig. 3 can also be implemented together in a further embodiment of a collector 10 in order to achieve an even higher level of optimization. List of reference symbols

[0034] 10 Collector 11 Collector housing 12 Base section 13 Cover section 14 Riser pipe 15 Riser pipe 16 Separator plate on the base section 17 Medium-pressure connection 18 Pipe section 19 Separator plate in the area of ​​the medium-pressure connection 20 Additional heat exchanger 21 Heat exchanger 22 Refrigerant inlet 23 Refrigerant outlet

Claims

1. Collector (10) for a refrigerant circuit with a sump collecting the condensed refrigerant as the bottom part (12) of a collector housing (11) which has a cover part (13), and with pipes for the refrigerant inlet (14) and the refrigerant outlet (15) into the collector (10), characterized in that the collector (11) has at least one, preferably both of the following features: a) a medium-pressure connection (17) for an intermediate injection of coolant is provided in the upper region of the collector housing (11) and comprises a pipe part (18) which projects into the interior of the collector housing (11) and whose free end comes to lie below the cover part (13) at a distance from the latter, b) an integrated additional heat exchanger (20) which is arranged in the lower part of the collector housing (11).

2. Collector (10) according to claim 1, characterized in that the medium pressure connection (17) is arranged laterally in the wall of the collector housing (11).

3. Collector (10) according to claim 1, characterized in that the medium pressure connection (17) is arranged in the cover part (13) of the collector housing (11).

4. Collector (10) according to one of claims 1 to 3, characterized in that in the collector housing (11) below the pipe part (18) a partition wall is provided which divides the interior of the collector housing (11) into an upper and a lower region.

5. Collector (10) according to claim 1, characterized in that the additional heat exchanger (20) comprises a refrigerant inlet (22) and a refrigerant outlet (23) which laterally penetrate the collector housing (11).

6. Collector (10) according to claim 5, characterized in that the additional heat exchanger (20) has one of the following features: the bent tube of the heat exchanger (21) is designed as a smooth tube, internally finned and / or externally finned.

7. Collector (10) according to one of claims 2 or 5 to 6, characterized in thatthe pipes for the refrigerant inlet (14) and the refrigerant outlet (15) into the collector (10) are designed as riser pipes (14, 15) and pass through the collector housing (11) in its housing interior from the cover part (13) into the sump and that in the region of the sump a flow calming means in the form of a separating plate (16) is arranged between the riser pipes (14, 15).

8. Collector (10) according to one of claims 1 to 7, characterized by a two-, three- or multi-part collector housing (11) with a bowl-like base part (12) and a hood-like cover part (13), wherein optionally one or more connecting jacket parts are arranged between the base part (12) and the cover part (13).

9. Collector (10) according to one of the preceding claims, characterized in thatthe collector (10) can be operated bidirectionally, so that each of the riser pipes (14, 15) can be used both as an inlet pipe and as an outlet pipe for the refrigerant mass flow.

10. Heat pump with a collector (10) according to one of claims 1 to 9 in the refrigerant circuit.

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