EP1215451A1 - Expansion device in particular for use within combined refrigeration and heat pump systems with carbon dioxide as refrigerant - Google Patents

Abstract

The expansion organ (1) is designed so that it can be subjected to a refrigerant flow from both sides and that the through flowable cross section of the expansion organ alters with a change of the flow direction of the refrigerant (8). So that the expansion organ has at least one throttle duct (4), facilitating the throttle effect in a flow direction (8.1), and in addition at least one further blocking throttle duct (5) is provided, flowable through only in the flow direction (8.2). So that the blocking effect in the flow direction is effected by at least one mechanical sealing element. Which closes the duct by the pressure of the flowing refrigerant, so that automatically depending on the flow direction of the blocking throttle duct, either it can be or is closed by the through flow of the refrigerant.

Description

The invention relates to a relaxation organ, which in particular for Use in combined refrigeration systems and heat pumps with carbon dioxide as Refrigerant is suitable.

Relaxation organs are components of refrigeration systems and Heat pumps, which are used to relax the refrigerant.

Refrigeration systems and heat pumps are used to cool or heat Utility rooms. The seasonal climatic changes Conditions often require a heating system in winter and in the Transitional period and a cooling system in summer.

In the prior art, the monofunctional use of Refrigeration systems or heat pumps, combinations of these are known. For example, for alternative heating or cooling of utility rooms, such as Living or office rooms as well as storage rooms or for cooling and Heating the passenger compartments of motor vehicles.

The latter application illustrates very well the possibility of combining and complementing refrigeration systems and heat pumps.
Conventional passenger compartment heating using the engine waste heat for winter is a standard component in motor vehicles, but it is becoming increasingly important to develop alternative heat sources for this. This is due to the fact that modern combustion or electric motors generate less and less waste heat and the amount of heat that can be used to heat the passenger compartment is becoming ever smaller.

In addition, in winter, especially when starting with a cold engine, it does not immediately sufficient waste heat is provided for the passenger compartment heating.

Increasingly, motor vehicles for cooling the passenger compartment in the In summer also equipped with a refrigeration system, air conditioning.

So it made sense to be an additional source of heat for the Passenger compartment heating to the ambient heat by means of a heat pump open up and the existing refrigeration system for a combined Refrigeration systems - to modify heat pump operation or at least part of the compression work of the refrigerant compressor for the To use passenger compartment heating.

The latter concept realizes a solution according to US 6 041 849. This sees the circuit of a refrigeration system, which with an additional Relaxation organ and a pressure control the compression work of the Refrigerant compressor in usable for passenger compartment heating Converts thermal energy. However, this solution only uses that Compression work and converts this into thermal energy This does not make the heat pump function use of ambient heat realized.

Overall, however, there are favorable operating conditions for the in motor vehicles combined refrigeration systems - heat pump operation and use of the Ambient heat.

According to the concept of EP 0 945 290 A2, a refrigeration system is all in one Motor vehicle with an internal combustion engine modified such that with a additional exhaust gas heat exchanger and two additional Reusable shut-off devices with wiring according to the invention both a Refrigeration as well as a heat pump operation, depending on the Temperature requirements inside the passenger compartment is possible.

Is particularly disadvantageous about this known prior art determine that in the solution according to US 6 041 849 only the Compression work of the refrigerant compressor used to generate heat and that continues to be a pressure control and an associated control valve is necessary for the operation of the device.

The teaching according to the invention of EP 0 945 290 A2 overcomes the mentioned Disadvantages, however, the disclosure of the execution of the Expansion device for the combined refrigeration system heat pump operation concluded that one from both sides flowable relaxation element in the described embodiment is elaborately designed. The relaxation organ is supposed to be in a spatial Unit designed as a combined expansion valve and in both Flow directions can be switched.

Such expansion valves or arrangements of these, which in the different flow directions are connected relatively expensive due to construction. This is a major disadvantage since that Expansion valve itself already has a high value relative to the refrigeration system and the combined refrigeration system or heat pump more complicated expansion valve or even two expansion valves with the necessary connecting lines and shut-off devices would be significantly more expensive.

In addition, the process flow in the refrigeration or the Heat pump circuit especially in processes with carbon dioxide as Refrigerants different. Before the refrigerant is released, this lies with it with different densities. This leads to a relaxation organ these different processes should enable, which in turn the technical and design requirements increased and such Component more expensive.

At the present time, the refrigerant R134a is predominantly used in the Motor vehicle air conditioning used, but other refrigerants, such as Carbon dioxide, propane or butane for their possible uses examined.

The high-pressure refrigerant carbon dioxide plays an important role in this. in the Compare processes with R134a and carbon dioxide, for example this has approximately the same efficiency in refrigeration system operation. Become However, in the future systems in heat pump operation will be striven for Carbon dioxide due to the supercritical heat emission, the low Pressure ratio, a constant overpressure of the carbon dioxide on the Low pressure side - and therefore particularly suitable in the overall system. The latter property means that there is none due to the constant overpressure Impurities or foreign gases can get into the system.

Added to that is the fact that the process performance figure with Carbon dioxide at an exit temperature of the carbon dioxide from the Gas cooler - heat exchanger for passenger compartment heating - from 30 ° C Performance figures of comparable systems with R134a or R290 clearly is superior. The lower the temperature, the better is carbon dioxide than Refrigerant suitable for the applications mentioned.

The higher operating pressure in a system with carbon dioxide as a refrigerant requires new components, but as the past has shown, classified as manageable. For this purpose, components with small Flow cross sections and filling volumes developed.

It is an object of the invention to construct a relaxation organ simple to train, which is thus also inexpensive to manufacture. In addition, that should Relaxation device in combined refrigeration systems - heat pumps can be used be and continue the peculiarities of the process management of the combined Refrigeration systems - heat pump operation due to its constructive design consider.

This object is achieved by the combination of features of Main claim solved, the sub-claims show further advantageous Embodiments of the invention.

The concept of the invention is that the relaxation organ of both sides can be flowed through with refrigerant and that the flowable cross section of the relaxation organ automatically at one Change in the flow direction of the refrigerant changes, which Relaxation organ to at least one, the throttling effect in one Has flow direction enabling throttle channel and that continues at least one other, only in the other direction of flow flow-through shut-off throttle duct is present, the shut-off effect is brought about by a mechanical closure element, which by the Pressure of the flowing refrigerant closes the shut-off throttle duct and thereby automatically depending on the flow direction of the Shut-off throttle duct can either be flowed through by refrigerant or is closed.

With the object of the invention, both the Realize heat pump and refrigeration system operation. Especially with the Using carbon dioxide as a refrigerant changes the density before Relaxation organ very clearly. It is therefore during the Heat pump operation only a significantly smaller flow cross section in the Relaxation device necessary compared to that of the refrigeration system.

The proposed solution provides a simple and effective solution Multi-channel solution. At least one throttle channel is used in both Flows through the flow. Another channel, below Shut-off throttle channel is only in one direction of flow flow through. The shut-off effect in the other is advantageous Direction of flow caused by a mechanical closure element, which by the pressure of the flowing refrigerant the shut-off throttle duct closes and thereby automatically depending on the flow direction of the Shut-off throttle channel can be flowed through once by refrigerant and in the other direction the shut-off throttle duct is closed.

Fig. 1:

Längsschnitt eines Entspannungsorgans mit Drosselkanal im Gehäuse

Fig. 2:

Längsschnitt eines Entspannungsorgans mit Drosselkanal in der Kanalscheibe

Fig. 3:

Längsschnitt eines Entspannungsorgans im Wärmepumpenbetrieb

Fig. 4:

Längsschnitt eines Entspannungsorgans im Kälteanlagenbetrieb

Fig. 5:

Querschnitt V-V, Kanalscheibe in Absperrstellung

Fig. 6:

Querschnitt VI-VI, Kanalscheibe in Durchflussstellung

Further details, features and advantages of the invention result from the following description of exemplary embodiments with reference to the associated drawings. Show it:

Fig. 1:

Longitudinal section of an expansion device with throttle channel in the housing

Fig. 2:

Longitudinal section of an expansion device with a throttle channel in the channel disk

Fig. 3:

Longitudinal section of an expansion device in heat pump operation

Fig. 4:

Longitudinal section of an expansion device in refrigeration plant operation

Fig. 5:

Cross-section VV, channel disc in the shut-off position

Fig. 6:

Cross section VI-VI, channel disc in flow position

1 shows an embodiment of the invention. The Expansion device 1 is in a refrigerant circuit Refrigerant connection lines 2 integrated and has as a mechanical Closing element one movable in a refrigerant and pressure tight Housing 6 arranged channel disc 3, which depending on the Flow direction 8 of the refrigerant in two different positions Housing 6 occupies. In each position there is a different one Flow cross section released by the expansion device 1. The Expansion device 1 has at least one throttle duct 4, which is shown in FIG. 1 is advantageously integrated into the housing 6 of the relaxation element 1. Farther the channel disk 3 has two shut-off throttle channels 5 for refrigerant. In the flow direction 8.1 of the refrigerant shown is only the Throttle channel 4 flows through. In the other position of the not shown Channel plate 3 with opposite flow direction of the refrigerant flow through the throttle duct 4 and the shut-off throttle ducts 5.

An advantageous embodiment, not shown, is to design the throttle duct 4 so that it can be shut off. In this way, it is possible for the relaxation element 1, if necessary, to have the function of a non-return valve also implemented.
It is also advantageous to design the throttle duct 4 simply as a groove in the duct disc 3 or the housing 6 in terms of production technology.

Fig. 2 shows a relaxation element 1, which is also a mechanical Closing element a movable in the refrigerant and pressure tight Housing 6 arranged channel plate 3. Again it takes Channel disk 3 two different depending on the flow direction 8 Positions in the housing 6. There is a different one in each position Flow cross section from the expansion element 1 for the refrigerant released, the channel disc 3 in this advantageous embodiment both at least one throttle channel 4 and at least one Shut-off throttle duct 5.

The illustration in FIG. 3 shows a relaxation element 1 according to the invention Function when refrigerant flows in the flow direction 8.1, For example, in a combined heat pump circuit Refrigeration system - heat pump. The channel disc is affected by the flow pressure pressed against the housing 6. The surfaces of Housing 6 and channel disk 3 are designed as sealing surfaces 7, that the throttling effect of the relaxation element 1 as a whole and the Shut-off effect of the shut-off throttle duct 5 are realized. In this position the channel disk, only the throttle channel 4 is flowed through by refrigerant Shut-off throttle channels 5 are not flowed through.

In addition to Fig. 3, Fig. 4 shows the inventive Relaxation device 1 in function when refrigerant flows through Flow direction 8.2, for example in the refrigeration system circuit combined refrigeration system - heat pump. Both the Throttle channel 4 and the shut-off throttle channels 5 of refrigerant flows through. In this position, the sealing surfaces 7 have the channel disk 3 the function of keeping the refrigerant flow through the housing 6 low or completely prevent it. The refrigerant essentially only flows through the channels provided, the throttle channels 4, the shut-off channels 5th

Fig. 5 shows a cross section to the flow direction 8. The housing 6 and the channel disk 3 and the channels 4, 5 are each with an oval cross section executed. Equally advantageous is the design of the channels with a round one or other cross-sections deviating from the round cross-section.

The ends of the throttle ducts 4 and the shut-off throttle ducts 5 can be seen, the shut-off throttle channels 5 in the direction of flow 8.1 of the Sealing surface 7 shut off and thus not be flowed through by refrigerant.

6, the channels 4, 5 of refrigerant are in the flow direction 8.2 flows through. In this position, the sealing surface 7 merely causes that not uncontrolled refrigerant through the housing 6 and on the Channel disk 3 passes the relaxation element 1. The quality of the Overall, sealing surfaces 7 only have to be so precise that the desired one Throttling effect is still given. This makes it easy to do designed sealing surface 7 calculate the amount of refrigerant passing and it can be dispensed with complex to produce sealing surfaces 7 what again an inexpensive manufacture of the invention Relaxation organ allows.

Both the throttle duct 4 and / or the shut-off throttle duct 5 can According to the invention in the channel disk 3 rectilinear, arcuate or be spiral shaped. This way it is possible with one longer duct to accommodate it in a compact duct disc and thus a space-saving relaxation element 1 according to the invention To make available.

Furthermore, it is advantageous for the channel disk 3 in the housing 6 Movement from one position to another after changing the To guide the flow direction 8 of the refrigerant mechanically. Such mechanical guidance is advantageous as a recess with a corresponding lead.

About the design and the quantitative variation of the channel cross sections, the Ratio of the duct cross sections of throttle duct 4 and Shut-off throttle channel 5 to each other and the length of the channels can be Relaxation organ 1 according to the invention for use in Adapt refrigerant circuits with different refrigerants. Partially all that is required is to replace the channel disk 3 in order to combine it Refrigeration - heat pump system with the invention Switch relaxation device 1 to a new refrigerant, which is also seen cost-effectively over a longer period of time. So can by replacing the channel disk 3, the exchange of the entire Component when switching to a new refrigerant for a combined Refrigeration system - heat pump can be avoided.

In particular, the channel disks for the refrigerants carbon dioxide, R134a and R290 can be optimized.

The use of the relaxation organ according to the invention is about mobile application of use in motor vehicles also for stationary systems advantageous.

LIST OF REFERENCES

1

expansion element

2

Refrigerant communication line

3

channel disk

4

throttle channel

5

Absperrdrosselkanal

6

casing

7

sealing surface

8th

Refrigerant flow direction

8.1

Refrigerant flow direction in heat pump operation

8.2

Refrigerant flow direction in refrigeration system operation

Claims (10)

Expansion device, in particular for use in combined refrigeration systems and heat pumps with carbon dioxide as the refrigerant, characterized in that the expansion device (1) can be flowed through from both sides with refrigerant and that the flow-through cross-section of the expansion device automatically changes when the flow direction of the refrigerant (8 ) changes, the expansion element (1) for this purpose having at least one throttle channel (4) that enables the throttling effect in one flow direction (8.1) and that at least one further shut-off throttle channel (5) that can only be flowed through in the other flow direction (8.2) is present, The shut-off effect in the direction of flow (8.1) is brought about by at least one mechanical closure element which closes the shut-off throttle channel (5) by the pressure of the flowing refrigerant and thereby automatically locks the shut-off throttle channel (5 ) refrigerant can either flow through or is closed. Relaxation element according to claim 1, characterized in that the relaxation element (1) as a mechanical closure element has a channel disk (3) which is movably arranged in a refrigerant and pressure-tight housing (6) and which, depending on the direction of flow (8), has two different positions in the housing ( 6) and a different flow cross-section is released by the expansion element (1) in each position, the expansion element (1) having at least one throttle duct (4) and the duct disc (3) having at least one shut-off throttle duct (5) for refrigerants and in one flow direction (8.1) of the refrigerant flows through the throttle channel (4) and that in the other flow direction (8.2) of the refrigerant through the throttle channel (4) and the shut-off throttle channel (5). Expansion element according to claim 1, characterized in that the expansion element (1) as a mechanical closure element has a channel plate (3) which is movably arranged in a refrigerant and pressure-tight housing (6), the channel plate (3) having at least one shut-off throttle channel (5) and has at least one throttle channel (4). Relaxation device according to claim 2, characterized in that the throttle channel (4) is designed to be shut off. Relaxation device according to claim 4, characterized in that the throttle channel (4) is designed as a groove in the interior of the housing (6) or as a groove in the channel disc (3). Relaxation element according to one of claims 2 to 5, characterized in that the surfaces of the channel plate (3) and the housing (6) touching during the flow of the refrigerant through the relaxation element (1) are designed as sealing surfaces (7) such that the Throttling effect of the expansion element (1) as a whole and the shut-off effect of the shut-off throttle duct (5) in the flow direction (8.1) are realized. Relaxation device according to one of claims 1 to 6, characterized in that the throttle duct (4) and the shut-off throttle duct (5) have circular cross sections. Relaxation device according to one of claims 1 to 7, characterized in that the throttle channel (4) and / or the shut-off throttle channel (5) are rectilinear, arc-shaped or spiral-shaped. Expansion device according to one of claims 2 to 8, characterized in that the channel disk (3) in the housing (6) is mechanically guided during the movement after changing the flow direction (8) of the refrigerant. Expansion device according to one of claims 2 to 9, characterized in that the expansion device (1) with different channel disks (3) can be adapted to use in refrigerant circuits with different refrigerants such as carbon dioxide, R134a or R290 and can be used in stationary or mobile systems.

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