EP4194771A1 - Refrigeration cycle - Google Patents
Refrigeration cycle Download PDFInfo
- Publication number
- EP4194771A1 EP4194771A1 EP22213224.3A EP22213224A EP4194771A1 EP 4194771 A1 EP4194771 A1 EP 4194771A1 EP 22213224 A EP22213224 A EP 22213224A EP 4194771 A1 EP4194771 A1 EP 4194771A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- compressor
- heat exchanger
- evaporator
- refrigeration circuit
- passage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 238000005057 refrigeration Methods 0.000 title claims abstract description 31
- 239000003507 refrigerant Substances 0.000 claims abstract description 37
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 12
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 12
- 238000002347 injection Methods 0.000 claims description 10
- 239000007924 injection Substances 0.000 claims description 10
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 5
- 239000001569 carbon dioxide Substances 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 5
- 238000010586 diagram Methods 0.000 description 9
- 238000000034 method Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- 125000004122 cyclic group Chemical group 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000009835 boiling Methods 0.000 description 2
- 238000004939 coking Methods 0.000 description 2
- 230000003750 conditioning effect Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
- F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B5/00—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity
- F25B5/02—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity arranged in parallel
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
- F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/07—Details of compressors or related parts
- F25B2400/072—Intercoolers therefor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/22—Refrigeration systems for supermarkets
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
- F25B2700/2115—Temperatures of a compressor or the drive means therefor
- F25B2700/21151—Temperatures of a compressor or the drive means therefor at the suction side of the compressor
Definitions
- the invention relates to a refrigeration circuit, comprising at least the following components, which follow one another in the direction of refrigerant flow: a compressor, a heat-emitting heat exchanger, a throttle element, and an evaporator.
- a refrigeration circuit comprising at least the following components, which follow one another in the direction of refrigerant flow: a compressor, a heat-emitting heat exchanger, a throttle element, and an evaporator.
- Such refrigeration circuits are the expert from JP 2001- 349 623 A , the JP 2003- 194 432 A , the U.S. 2009/0 071 177 A and the JP 2001 - 116 376 A known.
- a refrigeration cycle is a system designed to cool down equipment to a desired level, such as food refrigeration cabinets.
- a refrigerant that is moved in the closed circuit undergoes various changes in its physical state one after the other: the gaseous refrigerant is first compressed by a compressor. In the subsequent heat exchanger, it condenses while releasing heat. The liquid refrigerant is then expanded due to the pressure change via a throttling element, for example an expansion valve or a capillary tube. In the downstream evaporator, the refrigerant evaporates while absorbing heat at a low temperature (evaporative cooling). The cycle can now start all over again. The process must be done from the outside by supplying mechanical Work (drive power) can be kept going via the compressor.
- the refrigeration circuit comprises a heat exchanger with two passages, which is designed for an exchange of thermal energy between the two passages, the first passage being connected upstream of the inlet of the compressor and downstream of the first evaporator, and the second passage upstream of the evaporator and downstream of the throttle element.
- the refrigeration cycle also includes a medium-pressure tank.
- the refrigerant is collected after the throttle element, ie the high-pressure valve.
- the heat exchanger is still arranged between the throttle element and the medium-pressure tank, ie the inlet of the medium-pressure tank is downstream of the second passage.
- the outlet of the medium-pressure tank on the liquid side is connected upstream of the evaporator.
- the invention is based on the consideration that problems with regard to the operating conditions of the compressor arise in particular from changing outside conditions such as the outside temperature or different load states on the evaporator.
- problems with regard to the operating conditions of the compressor arise in particular from changing outside conditions such as the outside temperature or different load states on the evaporator.
- the throttle element high-pressure valve
- These largely constant temperatures should therefore be used to stabilize the inlet temperature of the compressor.
- a heat exchanger should be provided that enables heat exchange between the refrigerant flow from the high-pressure valve and the refrigerant flow into the compressor. This stabilizes the compressor inlet temperature.
- a gas-side outlet of the medium-pressure container is advantageously connected to the inlet of the first passage via a medium-pressure valve.
- the medium-pressure valve is used to drain gaseous refrigerant from the medium-pressure tank and feed it directly back to the compressor.
- the heat exchanger is advantageously designed as a plate heat exchanger.
- a plate heat exchanger is formed from corrugated profiled plates, which are assembled in such a way that the refrigerant to be heated and then the heat-emitting refrigerant flows in each of the successive spaces.
- the plate pack is outward and between both refrigerant passages sealed and is held together, for example, with clamping screws or soldered.
- a plate heat exchanger offers the advantage that it is very easy to expand and therefore very easy to adapt to the required heat exchange quantities. In addition, it achieves a particularly good heat exchange, since the mass flow of each passage is pressed through several small channels in the plate. The passage through the small, wave-shaped channels also promotes the mixing of the previously combined mass flows.
- the heat exchanger is designed with regard to its dimensioning and heat transfer capacity between the refrigerant passages in such a way that the temperature difference at the outlets of the passages is preferably less than 2 K. This achieves a particularly stable temperature condition at the compressor inlet.
- a deep-freeze evaporator with a downstream deep-freeze compressor is arranged parallel to the evaporator between the liquid-side outlet of the medium-pressure container and the inlet of the first passage. This enables a parallel line with different temperature levels parallel to the evaporator already mentioned, so that, for example, normal refrigerated cabinets and freezer cabinets can be operated with one refrigeration circuit.
- an injection valve is advantageously arranged parallel to the evaporator between the liquid-side outlet of the medium-pressure container and the inlet of the first passage.
- this can also be used to Reduce discharge gas temperature after the compressor by refrigerant is injected bypassing the evaporator directly before the compressor or before the heat exchanger. As a rule, it should only be used if the suction gas conditioning by the heat exchanger is not sufficient due to special circumstances.
- a temperature sensor is advantageously arranged at the inlet and/or at the outlet of the first passage. These make it possible to precisely determine the temperature upstream and downstream of the heat exchanger and thus in particular at the compressor inlet. If the temperatures are too high, additional measures can then be taken as required, such as opening the injection valve described above.
- the refrigeration cycle is advantageously designed to operate with carbon dioxide as the refrigerant and/or the heat exchanger of the refrigeration cycle is a gas cooler.
- the heat exchanger described offers particular advantages, since precisely here the temperatures at the compressor can be particularly high.
- the refrigeration cycle is advantageously designed for the stationary cooling of refrigerated cabinets or cold rooms.
- the advantages achieved by the invention are in particular that the arrangement of a heat exchanger that transfers heat from the suction gas flow to the compressor into the refrigerant flow expanded in the high-pressure valve, conditioning the suction gas flow to the compressor to a stable temperature is achieved and in this way the compressor is optimized in terms of service life and function.
- FIG 1 shows a refrigeration circuit K, which is used for stationary cooling of freezers and freezers, for example in supermarkets.
- the refrigeration circuit K is described below based on a compressor 1 .
- the compressed refrigerant in the compressor 1 - in the exemplary embodiment carbon dioxide (designation according to DIN 8960: R-744) - is passed through a refrigerant line into a heat-emitting heat exchanger 2 designed as a gas cooler in the exemplary embodiment, in which the compressed refrigerant is cooled and liquefied. From there it flows via a throttle element 3 designed as a high-pressure valve into a medium-pressure container 5.
- a throttle element 3 designed as a high-pressure valve into a medium-pressure container 5.
- further components in particular an oil separator, are usually arranged. However, these are not shown for reasons of clarity.
- the refrigerant flows from a liquid-side outlet via an injection valve 8 into an evaporator 9.
- the refrigerant is expanded and absorbs heat, so that the desired cooling effect is reached.
- the refrigerant which is now in gaseous form again, flows back into the compressor 1, where it is compressed and the cycle begins again.
- the medium-pressure container 5 is connected to the inlet of the compressor at a gas-side outlet via a medium-pressure valve.
- a parallel deep-freeze line is provided in parallel with the injection valve 8 and the evaporator 9 .
- This also branches off from the liquid-side outlet of the medium-pressure container 5 and comprises an injection valve 10, a deep-freeze evaporator 11 and a deep-freeze compressor 12 in the flow direction of the refrigerant.
- the liquid-side outlet of the medium-pressure container 5 is connected to the inlet of the compressor 1 via an injection valve 7 . This serves to reduce temperatures that may be too high in the compressor by injecting liquid refrigerant as required. Too high temperatures in the compressor 1 can lead to damage.
- the refrigeration circuit K of FIG 1 a heat exchanger 4.
- This is designed as a plate heat exchanger and has two passages that are in thermal contact.
- the first passage is the inlet of the compressor 1 immediately upstream, ie it is the merging of the refrigerant lines behind the evaporator 9, freezer compressor 12, injection valve 7 and Medium pressure valve 6 downstream.
- the second passage of the heat exchanger 4 is arranged between the throttle element 3 and the inlet of the medium-pressure container 5 .
- the heat exchanger 4 is designed such that there is a maximum temperature difference of 2 K between the outlets of the passages. Since the temperature of the refrigerant expanded in the throttle element 3 is comparatively stable, regardless of the outside conditions, a stable temperature at the inlet of the compressor 1 is also achieved in this way. Temperature sensors 7.1 and 7.2 are provided in the first passage to the compressor 1 before and after the heat exchanger 4 to check the temperatures and, if necessary, to cause an additional opening of the injection valve 7.
- FIG 2 and 3 The influence of the additional heat exchanger 4 is shown using the pressure-enthalpy diagrams in FIG 2 and 3 explained. These each show the pressure on the ordinate in bar (10 - 120 bar) and the enthalpy on the abscissa in kJ/kg (80 - 600 kJ/kg).
- the diagrams each show for the in the refrigeration circuit K FIG 1 used refrigerant R-744 (carbon dioxide) the critical point, the boiling line and the dew line, as well as the isotherms. The isovapores are also shown within the boiling and dew line.
- compressor 1 The compression process in compressor 1 is shown in the diagram FIG 2 indicated by the upper right diagonal line.
- the heat exchanger 4 described above now establishes a thermal connection between the refrigerant downstream of the throttle element 3 and upstream of the compressor 1 .
- the effect of the heat exchanger 4 is shown in the diagram 3 shown.
- the change in state of both refrigerant flows in the two passages of the heat exchanger 4 takes place isobaric.
- the enthalpy increases.
- the temperature does not change.
- the enthalpy is reduced at the inlet of the compressor 1. Since the refrigerant is in the gas phase here, the temperature is also reduced as a result.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Devices That Are Associated With Refrigeration Equipment (AREA)
- Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
Abstract
Ein Kältekreislauf (K), umfassend zumindest folgende in Kältemittelflussrichtung aufeinander folgenden Bauteile: einen Verdichter (1), einen wärmeabgebenden Wärmeübertrager (2), ein Drosselorgan (3), und einen Verdampfer (9), soll eine besonders sichere Funktion und hohe Lebensdauer des Verdichters ermöglichen. Dazu umfasst der Kältekreislauf (K) einen Wärmeübertrager (4) mit zwei Durchleitungen, der für einen Austausch thermischer Energie zwischen den beiden Durchleitungen ausgebildet ist, wobei die erste Durchleitung dem Eintritt des Verdichters (1) vorgeschaltet und dem ersten Verdampfer (9) nachgeschaltet ist, und die zweite Durchleitung dem Verdampfer (9) vorgeschaltet und dem Drosselorgan (3) nachgeschaltet ist.A refrigeration circuit (K), comprising at least the following components that follow one another in the direction of refrigerant flow: a compressor (1), a heat-emitting heat exchanger (2), a throttle element (3), and an evaporator (9), is intended to ensure particularly reliable operation and a long service life of the Enable compressor. For this purpose, the refrigeration circuit (K) comprises a heat exchanger (4) with two passages, which is designed for an exchange of thermal energy between the two passages, the first passage being connected upstream of the inlet of the compressor (1) and downstream of the first evaporator (9). , and the second passage is connected upstream of the evaporator (9) and downstream of the throttle element (3).
Description
Die Erfindung betrifft einen Kältekreislauf, umfassend zumindest folgende in Kältemittelflussrichtung aufeinander folgenden Bauteile: einen Verdichter, einen wärmeabgebenden Wärmeübertrager, ein Drosselorgan, und einen Verdampfer. Solche Kältekreisläufe sind dem Fachmann aus der
Ein Kältekreislauf ist ein System, das dazu dient, eine Einrichtung auf ein gewünschtes Maß abzukühlen, beispielsweise Kühlmöbel für Lebensmittel. Ein Kältemittel, das in dem geschlossenen Kreislauf bewegt wird, erfährt nacheinander verschiedene Aggregatzustandsänderungen: Das gasförmige Kältemittel wird zunächst durch einen Verdichter komprimiert. Im folgenden Wärmeüberträger kondensiert es unter Wärmeabgabe. Anschließend wird das flüssige Kältemittel aufgrund der Druckänderung über ein Drosselorgan, zum Beispiel ein Expansionsventil oder ein Kapillarrohr, entspannt. Im nachgeschalteten Verdampfer verdampft das Kältemittel unter Wärmeaufnahme bei niedriger Temperatur (Siedekühlung). Der Kreislauf kann nun von vorne beginnen. Der Prozess muss von außen durch Zufuhr von mechanischer Arbeit (Antriebsleistung) über den Verdichter in Gang gehalten werden.A refrigeration cycle is a system designed to cool down equipment to a desired level, such as food refrigeration cabinets. A refrigerant that is moved in the closed circuit undergoes various changes in its physical state one after the other: the gaseous refrigerant is first compressed by a compressor. In the subsequent heat exchanger, it condenses while releasing heat. The liquid refrigerant is then expanded due to the pressure change via a throttling element, for example an expansion valve or a capillary tube. In the downstream evaporator, the refrigerant evaporates while absorbing heat at a low temperature (evaporative cooling). The cycle can now start all over again. The process must be done from the outside by supplying mechanical Work (drive power) can be kept going via the compressor.
Für die Funktion eines derartigen Kältekreislaufs ist es erforderlich, den Verdichter bei definierten Betriebszuständen zu halten. Einerseits muss vermieden werden, dass am Eintritt des Verdichters Flüssigkeit anfällt, zum anderen dürfen die Temperaturen des Verdichters nicht zu hoch werden. Schon ab ca. 140°C kann es beispielsweise zu Verkokungen im Öl kommen und Ventile können verkleben. Dies kann die Funktionsfähigkeit und Lebensdauer des Verdichters beeinträchtigen.For such a refrigeration circuit to function, it is necessary to keep the compressor in defined operating states. On the one hand, liquid must be prevented from accumulating at the compressor inlet, and on the other hand, the temperatures of the compressor must not become too high. For example, from around 140°C, coking can occur in the oil and valves can stick. This can affect the functionality and service life of the compressor.
Es ist daher Aufgabe der Erfindung, einen Kältekreislauf der eingangs genannten Art anzugeben, der eine besonders sichere Funktion und hohe Lebensdauer des Verdichters ermöglicht.It is therefore the object of the invention to specify a refrigeration circuit of the type mentioned at the outset, which enables the compressor to function particularly reliably and has a long service life.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, dass der Kältekreislauf einen Wärmeübertrager mit zwei Durchleitungen umfasst, der für einen Austausch thermischer Energie zwischen den beiden Durchleitungen ausgebildet ist, wobei die erste Durchleitung dem Eintritt des Verdichters vorgeschaltet und dem ersten Verdampfer nachgeschaltet ist, und die zweite Durchleitung dem Verdampfer vorgeschaltet und dem Drosselorgan nachgeschaltet ist.This object is achieved according to the invention in that the refrigeration circuit comprises a heat exchanger with two passages, which is designed for an exchange of thermal energy between the two passages, the first passage being connected upstream of the inlet of the compressor and downstream of the first evaporator, and the second passage upstream of the evaporator and downstream of the throttle element.
Weiter umfasst der Kältekreislauf einen Mitteldruckbehälter. In diesem wird das Kältemittel nach dem Drosselorgan, d.h. dem Hochdruckventil gesammelt. Der Wärmeübertrager ist dabei noch zwischen Drosselorgan und Mitteldruckbehälter angeordnet, d.h. der Eintritt des Mitteldruckbehälters ist der zweiten Durchleitung nachgeschaltet. Der flüssigkeitsseitige Austritt des Mitteldruckbehälters ist dabei dem Verdampfer vorgeschaltet.The refrigeration cycle also includes a medium-pressure tank. In this, the refrigerant is collected after the throttle element, ie the high-pressure valve. The heat exchanger is still arranged between the throttle element and the medium-pressure tank, ie the inlet of the medium-pressure tank is downstream of the second passage. The The outlet of the medium-pressure tank on the liquid side is connected upstream of the evaporator.
Die Erfindung geht dabei von der Überlegung aus, dass Probleme hinsichtlich der Betriebsbedingungen des Verdichters insbesondere durch wechselnde Außenbedingungen wie z.B. die Außentemperatur oder verschiedene Lastzustände am Verdampfer entstehen. Gleichzeitig wurde erkannt, dass insbesondere nach dem Drosselorgan (Hochdruckventil) hinter dem wärmeabgebenden Wärmeübertrager unabhängig von wechselnden Außenbedingungen vergleichsweise konstante Temperaturen vorliegen. Diese weitgehend konstanten Temperaturen sollten daher dazu genutzt werden, die Eingangstemperatur des Verdichters zu stabilisieren. Hierzu sollte ein Wärmeübertrager vorgesehen werden, der einen Wärmeaustausch zwischen dem Kältemittelstrom aus dem Hochdruckventil und dem Kältemittelstrom in den Verdichter ermöglicht. Hierdurch wird die Verdichtereintrittstemperatur stabilisiert.The invention is based on the consideration that problems with regard to the operating conditions of the compressor arise in particular from changing outside conditions such as the outside temperature or different load states on the evaporator. At the same time, it was recognized that, in particular after the throttle element (high-pressure valve) downstream of the heat-dissipating heat exchanger, there are comparatively constant temperatures, regardless of changing external conditions. These largely constant temperatures should therefore be used to stabilize the inlet temperature of the compressor. For this purpose, a heat exchanger should be provided that enables heat exchange between the refrigerant flow from the high-pressure valve and the refrigerant flow into the compressor. This stabilizes the compressor inlet temperature.
Vorteilhafterweise ist dabei ein gasseitiger Austritt des Mitteldruckbehälters mit dem Eintritt der ersten Durchleitung über ein Mitteldruckventil verbunden. Das Mitteldruckventil dient dazu, bei übermäßigem Druck im Mitteldruckbehälter gasförmiges Kältemittel aus dem Mitteldruckbehälter abzulassen und direkt dem Verdichter wieder zuzuführen.A gas-side outlet of the medium-pressure container is advantageously connected to the inlet of the first passage via a medium-pressure valve. In the event of excessive pressure in the medium-pressure tank, the medium-pressure valve is used to drain gaseous refrigerant from the medium-pressure tank and feed it directly back to the compressor.
Der Wärmeübertrager ist vorteilhafterweise als Plattenwärmeübertrager ausgebildet. Ein solcher Plattenwärmeübertrager ist aus wellenförmig profilierten Platten gebildet, die so zusammengesetzt sind, dass jeweils in den aufeinanderfolgenden Zwischenräumen einmal das aufzuwärmende und danach das wärmeabgebende Kältemittel fließt. Das Plattenpaket ist nach außen und zwischen den beiden Kältemitteldurchgängen abgedichtet und wird beispielsweise mit Spannschrauben zusammengehalten oder verlötet. Ein Plattenwärmeüberträger bietet den Vorteil, dass er sehr gut erweiterbar und dadurch sehr gut an die benötigten Wärmeaustauschmengen anpassbar ist. Zudem erreicht er einen besonders guten Wärmeaustausch, da der Massenstrom jeder Durchleitung über mehrere kleine Kanäle in der Platte gedrückt wird. Die Durchleitung über die wellenförmig ausgeführten kleinen Kanäle begünstigen zudem die Durchmischung der zuvor zusammengeführten Massenströme.The heat exchanger is advantageously designed as a plate heat exchanger. Such a plate heat exchanger is formed from corrugated profiled plates, which are assembled in such a way that the refrigerant to be heated and then the heat-emitting refrigerant flows in each of the successive spaces. The plate pack is outward and between both refrigerant passages sealed and is held together, for example, with clamping screws or soldered. A plate heat exchanger offers the advantage that it is very easy to expand and therefore very easy to adapt to the required heat exchange quantities. In addition, it achieves a particularly good heat exchange, since the mass flow of each passage is pressed through several small channels in the plate. The passage through the small, wave-shaped channels also promotes the mixing of the previously combined mass flows.
Der Wärmeübertrager ist hinsichtlich seiner Dimensionierung und Wärmeübertragungsleistung zwischen den Kältemitteldurchleitungen derart ausgelegt, dass der Temperaturunterschied an den Austritten der Durchleitungen vorzugsweise weniger als 2 K beträgt. Hierdurch wird ein besonders stabiler Temperaturzustand am Verdichtereintritt erreicht.The heat exchanger is designed with regard to its dimensioning and heat transfer capacity between the refrigerant passages in such a way that the temperature difference at the outlets of the passages is preferably less than 2 K. This achieves a particularly stable temperature condition at the compressor inlet.
Vorteilhafterweise ist zwischen dem flüssigkeitsseitigen Austritt des Mitteldruckbehälters und dem Eintritt der ersten Durchleitung parallel zum Verdampfer ein Tiefkühl-Verdampfer mit nachgeschaltetem Tiefkühl-Verdichter angeordnet. Dieser ermöglicht parallel zum bereits genannten Verdampfer einen parallelen Strang mit unterschiedlichem Temperaturniveau, so dass z.B. normale Kühlmöbel und Tiefkühlmöbel mit einem Kältekreislauf betrieben werden können.Advantageously, a deep-freeze evaporator with a downstream deep-freeze compressor is arranged parallel to the evaporator between the liquid-side outlet of the medium-pressure container and the inlet of the first passage. This enables a parallel line with different temperature levels parallel to the evaporator already mentioned, so that, for example, normal refrigerated cabinets and freezer cabinets can be operated with one refrigeration circuit.
Weiterhin ist vorteilhafterweise zwischen dem flüssigkeitsseitigen Austritt des Mitteldruckbehälters und dem Eintritt der ersten Durchleitung parallel zum Verdampfer ein Einspritzventil angeordnet. Dieses kann, als zusätzlicher Schutz des Verdichters, ebenfalls dazu genutzt werden, die Druckgastemperatur nach dem Verdichter zu verringern, indem Kältemittel unter Umgehung des Verdampfers direkt vor dem Verdichter bzw. vor dem Wärmeübertrager eingespritzt wird. Es sollte in der Regel nur dann zur Anwendung kommen, wenn die Sauggaskonditionierung durch den Wärmeübertrager aufgrund besonderer Umstände nicht ausreicht.Furthermore, an injection valve is advantageously arranged parallel to the evaporator between the liquid-side outlet of the medium-pressure container and the inlet of the first passage. As additional protection for the compressor, this can also be used to Reduce discharge gas temperature after the compressor by refrigerant is injected bypassing the evaporator directly before the compressor or before the heat exchanger. As a rule, it should only be used if the suction gas conditioning by the heat exchanger is not sufficient due to special circumstances.
Vorteilhafterweise ist hierzu am Eintritt und/oder am Austritt der ersten Durchleitung jeweils ein Temperaturfühler angeordnet. Diese ermöglichen es, die Temperatur vor und nach dem Wärmeübertrager und damit insbesondere am Eintritt des Verdichters exakt zu bestimmen. Bei zu hohen Temperaturen können dann bedarfsweise zusätzliche Maßnahmen erfolgen, wie z.B. die Öffnung des oben beschriebenen Einspritzventils.For this purpose, a temperature sensor is advantageously arranged at the inlet and/or at the outlet of the first passage. These make it possible to precisely determine the temperature upstream and downstream of the heat exchanger and thus in particular at the compressor inlet. If the temperatures are too high, additional measures can then be taken as required, such as opening the injection valve described above.
Der Kältekreislauf ist vorteilhafterweise zum Betrieb mit Kohlendioxid als Kältemittel ausgelegt und/oder der Wärmeüberträger des Kältekreislaufs ist ein Gaskühler. Bei derartigen Kältekreisläufen, die für den Betrieb mit Kohlendioxid ausgelegt sind, bietet der beschriebene Wärmeübertrager besondere Vorteile, da gerade hier die Temperaturen am Verdichter besonders hoch sein können.The refrigeration cycle is advantageously designed to operate with carbon dioxide as the refrigerant and/or the heat exchanger of the refrigeration cycle is a gas cooler. In the case of such refrigeration circuits, which are designed for operation with carbon dioxide, the heat exchanger described offers particular advantages, since precisely here the temperatures at the compressor can be particularly high.
Der Kältekreislauf ist vorteilhafterweise zur stationären Kühlung von Kühlmöbeln oder Kühlräumen ausgelegt.The refrigeration cycle is advantageously designed for the stationary cooling of refrigerated cabinets or cold rooms.
Die mit der Erfindung erzielten Vorteile bestehen insbesondere darin, dass durch die Anordnung eines Wärmeübertragers, der Wärme aus dem Sauggasstrom zum Verdichter in den im Hochdruckventil entspannten Kältemittelstrom überträgt, eine Konditionierung des Sauggasstroms zum Verdichter auf eine stabile Temperatur erreicht wird und auf diese Weise der Verdichter hinsichtlich Lebensdauer und Funktion optimiert wird.The advantages achieved by the invention are in particular that the arrangement of a heat exchanger that transfers heat from the suction gas flow to the compressor into the refrigerant flow expanded in the high-pressure valve, conditioning the suction gas flow to the compressor to a stable temperature is achieved and in this way the compressor is optimized in terms of service life and function.
Die Erfindung wird anhand von Zeichnungen näher erläutert. Darin zeigen:
- FIG 1
- einen Kältemittelkreislauf,
- FIG 2
- ein Druck-Enthalpie-Diagramm für einen Kältemittelkreislauf aus dem Stand der Technik, und
- FIG 3
- ein Druck-Enthalpie-Diagramm für den Kältemittelkreislauf aus
FIG 1 .
- FIG 1
- a refrigerant circuit,
- FIG 2
- a pressure-enthalpy diagram for a refrigerant circuit from the prior art, and
- 3
- a pressure-enthalpy diagram for the refrigerant circuit
FIG 1 .
Aus dem Mitteldruckbehälter 5 strömt das Kältemittel aus einem flüssigkeitsseitigen Austritt über ein Einspritzventil 8 in einen Verdampfer 9. Hier wird das Kältemittel entspannt und nimmt Wärme auf, so dass die gewünschte Kühlwirkung erreicht wird. Aus dem Verdampfer 9 strömt das nun wieder gasförmige Kältemittel zurück in den Verdichter 1, wird dort komprimiert und der Kreislauf beginnt von neuem.From the medium-
Um je nach Betriebszustand einen ggf. zu hohen Druck im Mitteldruckbehälter 5 ablassen zu können, ist der Mitteldruckbehälter 5 an einem gasseitigen Austritt über ein Mitteldruckventil mit dem Eintritt des Verdichters verbunden.In order to be able to release a possibly too high pressure in the medium-
Parallel zu Einspritzventil 8 und Verdampfer 9 ist ein paralleler Tiefkühlstrang vorgesehen. Dieser zweigt ebenfalls vom flüssigkeitsseitigen Austritt des Mitteldruckbehälters 5 ab und umfasst in Flussrichtung des Kältemittels ein Einspritzventil 10, einen Tiefkühl-Verdampfer 11 und einen Tiefkühl-Verdichter 12.A parallel deep-freeze line is provided in parallel with the
Wiederum parallel zu Einspritzventil 8 und Verdampfer 9 sowie zum eben beschriebenen Tiefkühlstrang ist der flüssigkeitsseitige Austritt des Mitteldruckbehälters 5 mit dem Eintritt des Verdichters 1 über ein Einspritzventil 7 verbunden. Dieses dient dazu, ggf. zu hohe Temperaturen im Verdichter durch bedarfsweises Einspritzen flüssigen Kältemittels zu senken. Zu hohe Temperaturen im Verdichter 1 können zu Beschädigungen führen.Again parallel to the
Um dies zu vermeiden, weist der der Kältekreislauf K der
Der Wärmeübertrager 4 ist hinsichtlich seiner Dimensionierung so ausgelegt, dass zwischen den Austritten der Durchleitungen ein Temperaturunterschied von maximal 2 K besteht. Da die Temperatur des im Drosselorgan 3 entspannten Kältemittels unabhängig von den Außenbedingungen vergleichsweise stabil ist, wird so auch eine stabile Temperatur am Eintritt des Verdichters 1 erreicht. Zur Prüfung der Temperaturen und ggf. Veranlassung einer zusätzlichen Öffnung des Einspritzventils 7 sind in der ersten Durchleitung zum Verdichter 1 vor und hinter dem Wärmeüberträger 4 Temperatursensoren 7.1 und 7.2 vorgesehen.With regard to its dimensioning, the
Der Einfluss des zusätzlichen Wärmeübertragers 4 wird anhand der Druck-Enthalpie-Diagramme in
In beiden Diagrammen ist der oben beschriebene Kreisprozess im Druck-Enthalpie-Diagramm aufgetragen. Dabei zeigt
Der Verdichtungsprozess im Verdichter 1 ist im Diagramm der
Der oben beschriebene Wärmeübertrager 4 stellt nun eine thermische Verbindung zwischen dem Kältemittel nach dem Drosselorgan 3 und vor dem Verdichter 1 her. Der Effekt des Wärmeübertragers 4 wird im Diagramm der
Dieser Effekt verschiebt die gesamte Zustandsänderung im Verdichter 1. Wie aus den Diagrammen erkennbar, sinkt die Endtemperatur am Austritt des Verdichters 1 von ca. 145 °C auf ca. 100 °C. Hierdurch werden Verkokungen im Öl und ein Verkleben von Ventilen vermieden.This effect shifts the entire state change in
- 11
- Verdichtercompressor
- 22
- wärmeabgebender Wärmeübertragerheat-emitting heat exchanger
- 33
- Drosselorganthrottle organ
- 44
- Wärmeübertragerheat exchanger
- 55
- Mitteldruckbehältermedium pressure vessel
- 66
- Mitteldruckventilmedium pressure valve
- 77
- Einspritzventilinjector
- 7.17.1
- Temperatursensortemperature sensor
- 7.27.2
- Temperatursensortemperature sensor
- 88th
- Einspritzventilinjector
- 99
- VerdampferEvaporator
- 1010
- Einspritzventilinjector
- 1111
- Tiefkühl-VerdampferFreezer evaporator
- 1212
- Tiefkühl-Verdichterfreezer compressor
- KK
- Kältekreislaufrefrigeration cycle
Claims (9)
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DE102021132848.9A DE102021132848A1 (en) | 2021-12-13 | 2021-12-13 | refrigeration cycle |
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Citations (8)
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JP2001004235A (en) * | 1999-06-22 | 2001-01-12 | Sanden Corp | Steam compression refrigeration cycle |
JP2001116376A (en) | 1999-10-20 | 2001-04-27 | Sharp Corp | Supercritical vapor compression type refrigerating cycle |
JP2001349623A (en) | 2000-06-06 | 2001-12-21 | Daikin Ind Ltd | Freezer device |
JP2003194432A (en) | 2001-10-19 | 2003-07-09 | Matsushita Electric Ind Co Ltd | Refrigerating cycle device |
US20090071177A1 (en) | 2006-03-27 | 2009-03-19 | Mitsubishi Electric Corporation | Refrigerant Air Conditioner |
US20100115975A1 (en) * | 2007-04-24 | 2010-05-13 | Carrier Corporation | Refrigerant vapor compression system and method of transcritical operation |
US20120227426A1 (en) * | 2011-03-10 | 2012-09-13 | Streamline Automation, Llc | Extended Range Heat Pump |
US20130145791A1 (en) * | 2011-06-16 | 2013-06-13 | Hill Phoenix, Inc. | Refrigeration system |
-
2021
- 2021-12-13 DE DE102021132848.9A patent/DE102021132848A1/en active Pending
-
2022
- 2022-12-12 DE DE202022106923.9U patent/DE202022106923U1/en active Active
- 2022-12-13 EP EP22213224.3A patent/EP4194771A1/en active Pending
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001004235A (en) * | 1999-06-22 | 2001-01-12 | Sanden Corp | Steam compression refrigeration cycle |
JP2001116376A (en) | 1999-10-20 | 2001-04-27 | Sharp Corp | Supercritical vapor compression type refrigerating cycle |
JP2001349623A (en) | 2000-06-06 | 2001-12-21 | Daikin Ind Ltd | Freezer device |
JP2003194432A (en) | 2001-10-19 | 2003-07-09 | Matsushita Electric Ind Co Ltd | Refrigerating cycle device |
US20090071177A1 (en) | 2006-03-27 | 2009-03-19 | Mitsubishi Electric Corporation | Refrigerant Air Conditioner |
US20100115975A1 (en) * | 2007-04-24 | 2010-05-13 | Carrier Corporation | Refrigerant vapor compression system and method of transcritical operation |
US20120227426A1 (en) * | 2011-03-10 | 2012-09-13 | Streamline Automation, Llc | Extended Range Heat Pump |
US20130145791A1 (en) * | 2011-06-16 | 2013-06-13 | Hill Phoenix, Inc. | Refrigeration system |
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DE202022106923U1 (en) | 2023-01-04 |
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