EP1914491A2 - Refrigeration system - Google Patents

Abstract

The system has a cooling medium compressor unit (12) that is arranged in a cooling medium circuit (10) and compresses the cooling medium to high pressure. A refrigeration stage has an refrigerated expansion cooling device (62) that is cooled in an active condition of an overall mass flow. A refrigerated main mass flow (TH) is guided to a refrigeration expansion unit, and a refrigerated additional mass flow (TZ) is generated.

Description

The invention relates to a refrigeration system, comprising a refrigerant circuit, in which a total mass flow of a refrigerant is guided, arranged in the refrigerant circuit, high-pressure side refrigerant cooling heat exchanger, a refrigerant circuit disposed in the expansion cooling means cools the total mass flow of the refrigerant in the active state and thereby a main mass flow of liquid Generates refrigerant and an additional mass flow of gaseous refrigerant, a reservoir for the main mass flow, at least one normal cooling mass flow from the reservoir taking normal cooling stage with a normal cooling expansion and this downstream, low pressure side, cooling capacity for normal cooling available normal cooling heat exchanger, a Tiefkühlgesamtmassenstrom from the reservoir entnehmende deep freezing stage with a Tiefkühpansionsorgan and a downstream cooling capacity available Uigh- yielding deep-freeze heat exchanger and with this deep-freeze heat exchanger downstream refrigeration compressor unit, and at least one arranged in the refrigerant circuit refrigerant compressor unit, which compresses the refrigerant of the main mass flow and the additional mass flow to high pressure.

Such a refrigeration system, which is particularly suitable for carbon dioxide as a refrigerant, is from the DE 10 2004 038 640 A1 known, wherein in this refrigeration system, the efficiency, especially in connection with the operated freezing stage, is not optimal.

The invention is therefore based on the object to improve a refrigeration system of the type described above in such a way that it has a better efficiency.

This object is achieved in a refrigeration system of the type described above according to the invention that the freezing stage for further cooling of the Tiefkühlgesamtmassenstroms a Tiefkühplexionskuhinrichtung which cools the Tiefkühlgesamtmassenstrom in the active state, thereby generating a Tiefkühpulsionsorgan supplied Tiefkühlhauptmassenstrom and a Tiefkühlzusatzmassenstrom.

The advantage of the solution according to the invention lies in the fact that the possibility was created by the Tiefkühplexionskühlinrichtung to increase the temperature to be absorbed at freezing temperature and thus further increase the efficiency of the refrigeration system according to the invention, wherein the potential for freezing temperature Enthalpieerhöhung by receiving heat energy in the Freezer heat exchanger is optimally adapted to the thermodynamic states of the refrigerant, in particular the thermodynamically possible states of carbon dioxide as a refrigerant.

In particular, an embodiment provides that this has to increase the available enthalpy difference in the heat exchanger or to further reduce the enthalpy of the main cooling mass flow Tiefkühleexpansionseinrichtung which relaxes the Tiefkühlgesamtmassenstrom in the active state and thereby generates a Tiefkühpulsionsorgan supplied in the freezer accumulator a Tiefkühlhauptmassenstrom and the Tiefkühlzusatzmassenstrom ,

With regard to the present in the Tiefkühlexpansionskuscheinrichtung deep frozen intermediate pressure no further details were made.

Preferably, it is provided here that the intermediate cryogenic pressure is between the intermediate pressure in the expansion cooling device and a suction pressure of the deep-freeze compressor unit in order to optimally adapt the enthalpy reduction possible by expansion in the deep-freeze cooling device to the conditions of the refrigeration system.

An expedient solution provides that in the deep-frozen expansion cooling device, the intermediate cryogenic pressure is at least approximately 2 bar lower than the intermediate pressure of the expansion cooling device.

It is even better if the intermediate cooling pressure is at least approximately 4 bar lower than the intermediate pressure of the expansion cooling device.

Furthermore, an expedient solution provides that in the deep-freeze expansion device the intermediate cryogenic pressure is at least approximately 2 bar higher than the suction pressure of the deep-freeze compressor unit.

It is even better if the intermediate cryogenic pressure is at least approximately 4 bar higher than the suction pressure of the refrigerated compressor unit.

It is particularly advantageous if in the Tiefkühlexpansionskühleinrichtung an intermediate cryogenic pressure is present, which is located in a central region of the pressure difference between the intermediate pressure in the expansion cooling device and the suction pressure of the frozen compactor unit.

A particularly expedient solution provides that in the Tiefkühlexpansionskühleinrichtung an intermediate cryogenic pressure is present, which is located in a middle third of a divided into three thirds pressure difference between the intermediate pressure in the expansion cooling device and the suction pressure of the frozen compactor unit.

With regard to the removal of the frozen additional mass flow, no further details have so far been given. Thus, for example, it would be conceivable also to compress the additional frozen mass flow via the deep-freeze compressor unit, optionally an additional compressor stage of the deep freeze compressor unit.

However, a particularly simple solution provides that the frozen additional mass flow is supplied to the refrigerant compressor unit, so that no compression takes place via the deep-freeze compressor unit.

In this case, it would still be possible to supply the additional frozen mass flow to a separate additional compressor stage of the refrigerant compressor unit.

A simplified embodiment of the refrigeration system according to the invention provides that in this the additional frozen mass flow is fed to a suction port of the refrigerant compressor unit and thus an additional compressor stage is not required.

It would still be conceivable to use a throttling device to set the intermediate cryogenic pressure to a desired level other than the pressure at the suction port.

A simple embodiment of the refrigeration system according to the invention, however, provides that the freeze-additive mass flow is supplied to the suction connection of the refrigerant compressor unit in a pressure-regulating manner and thus no additional measures for pressure regulation of the intermediate cryogenic pressure are required.

Appropriately, in one embodiment of the solution according to the invention, the intermediate cryogenic pressure is selected so that it lies in the region of the low pressure at the suction connection of the refrigerant compressor unit.

In the simplest case, the intermediate cryogenic pressure approximately corresponds to the low pressure at the suction connection of the refrigerant compressor unit.

Furthermore, in one embodiment of the solution according to the invention, the refrigerant compressor unit could be constructed such that it has different refrigerant compressors for the normal cooling mass flow and the additional frozen mass flow.

A particularly simple solution provides that the frozen additional mass flow is supplied together with the low-pressure expanded normal cooling mass flow of the refrigerant compressor unit, so that the refrigerant compressor unit sucks and compresses the sum of both mass flows.

With regard to the further compression of the frozen main mass flow compressed by the deep-freeze compressor unit, no further details have so far been given.

This deep-freeze main mass flow leaving the freezer compressor unit could also be fed to a separate compressor stage.

A structurally simple solution provides that the frozen main mass flow compressed by the deep-freeze compressor unit is fed to the refrigerant compressor unit and thus undergoes compression to high pressure by the refrigerant compressor unit.

The further compression of the main cooling mass flow can then take place via an additional compressor stage of the refrigerant compressor unit.

It is particularly favorable if the deep-freeze main mass flow compressed by the deep-freeze compactor unit is mixed with the expanded normal air mass flow stream and fed to a suction port of the refrigerant compressor unit. In this case, the mixing of the compacted, but heated mainstream cooling mass flow with the expanded, but cooler normal cooling mass flow causes the enthalpy of the main low-temperature mass flow to be lowered and thus sets a total enthalpy of the compacted main-body mass flow and the expanded normal-mass flow.

In particular, the thereby occurring heating of the expanded normal cooling mass flow caused by the frozen main mass flow compressed by the deep-freeze compressor unit causes the refrigerant to be compressed by the refrigerant compressor unit to be supplied substantially free of liquid components and thus superheated.

A particularly advantageous solution provides that the frozen main mass flow, the deep-freeze additive mass flow and the expanded normal-mass flow are compressed together and fed to the suction port of the refrigerant compressor unit and thus all of the aforementioned mass flows are compressed together by the refrigerant compressor unit.

This solution has the particular advantage that different operating conditions, that is, different cooling capacities of the normal cooling stage and the deep-freezing stage at least partially average and thus simplifies the control of the refrigerant compressor unit.

With regard to the. Operation of Tiefkühplexionskühleinrichtung were so far no further details.

Thus, an advantageous solution provides that the Tiefkühplexionskühleinrichtung reduces the enthalpy of the main cooling mass flow by at least 10% compared to the enthalpy of the total frozen cooling mass flow.

It is even more advantageous if the deep-freeze cooling device reduces the enthalpy of the main bulk of the cooling mass by at least 20%.

Furthermore, in an advantageous embodiment, the thermodynamic state of the main cooling mass flow can be defined by the fact that the deep cooling expansion cooling device generates the main cooling mass flow in a thermodynamic state whose pressure and enthalpy values are lower than those of the normal cooling mass flow.

In order to obtain an optimum cooling effect at the low temperature, it is preferably provided that the pressure and enthalpy values of the main cooling mass flow caused by the deep-freeze expansion device are close to the saturation curve in the enthalpy / pressure diagram.

It is even better if the pressure and enthalpy values of the main cooling mass flow caused by the deep-freeze expansion device are essentially on the saturation curve of the enthalpy / pressure diagram.

With regard to the operation of the expansion cooling device in connection with the embodiments described so far, no further details have been given. Thus, an advantageous embodiment provides that the expansion cooling device has an expansion element for the expansion of the total mass flow to the intermediate pressure and that a maximum value of the intermediate pressure is adjustable.

It is particularly advantageous if the intermediate pressure can be set to a maximum value of 40 bar or less, since this makes it easy to carry out the piping of at least the normal cooling stage.

The adjustability is achieved by adjustability of the expansion device, so that standard components usually approved up to this pressure can be used.

As an alternative or in addition to the adjustability of the expansion element, a further advantageous embodiment provides that the intermediate pressure can be set by supplying at least part of the additional mass flow to an additional suction port of the refrigerant compressor unit.

Such, provided with a Zusatzsauganschluss refrigerant compressor unit can be constructed in different ways. One solution provides that the refrigerant compressor unit have refrigerant compressor with additional compressor stages.

However, it is also conceivable to construct the refrigerant compressor unit from a multiplicity of refrigerant compressors and thereby to provide one of the refrigerant compressors for compressing the additional mass flow.

In particular, it is advantageous if the available at the Zusatzsauganschluss capacity of the refrigerant compressor unit is adjustable, so that on the setting of the available flow rate and the intermediate pressure is adjustable.

The adjustment of the delivery rate at Zusatzsauganschluss can be adjusted either by the number of active additional compressor stages or the number of individual provided for compressing the additional mass flow refrigerant compressor and / or the speed thereof.

Alternatively or in addition to adjusting the intermediate pressure by supplying the additional mass flow to a Zusatzsauganschluss the refrigerant compressor unit provides another solution that the intermediate pressure by supplying at least a portion of the additional mass flow to a suction port of the refrigerant compressor unit is adjustable.

This solution has the advantage that it is not necessary to provide additional compressor stages or special refrigerant compressors provided for the additional suction connection, but rather the latter Additional mass flow must be supplied only to the suction port of the refrigerant compressor unit, with which anyway a compression of the main mass flow of the refrigerant. However, this solution has a slight disadvantage in terms of reducing the efficiency.

Furthermore, when the additional mass flow to the suction port is supplied, it is necessary to provide an adjustable throttle element in order to be able to set the intermediate pressure with this.

A particularly favorable solution, which allows an optimal operation of the refrigeration system substantially in all operating conditions and in all temperature conditions, provides a control which feeds the additional mass flow either the Zusatzsauganschluss or this and in parts the suction port of the refrigerant compressor unit.

Thus, an intended Zusatzsauganschluss and the compressor power available at this time can always exploit, but keep the intermediate pressure below an adjustable maximum value in cases where a high additional mass flow, if at a large additional mass flow still a part thereof the suction port of the refrigerant compressor unit can be fed.

With regard to the operation of the expansion cooling device itself no further details have been made in connection with the previous explanation of the individual embodiments.

Thus, an advantageous embodiment provides that the expansion cooling device reduces the enthalpy of the main mass flow by at least 10% compared to the enthalpy of the total mass flow.

It is even more advantageous if the expansion cooling device reduces the enthalpy of the main mass flow by at least 20%.

With regard to the use of the expansion cooling device is provided in particular that the expansion cooling device is active in a supercritical operation of the refrigeration system.

Such supercritical operation is particularly in the use of carbon dioxide as a refrigerant and conventional ambient temperatures for cooling the heat exchanger.

In particular, it is provided in an advantageous embodiment that the expansion cooling device generates the main mass flow in a thermodynamic state whose pressure and enthalpy values are lower than those of a maximum of the saturation curve.

Furthermore, it is preferably provided that the pressure and enthalpy values of the main mass flow caused by the expansion cooling device are close to the saturation curve in the enthalpy / pressure diagram.

It is even better if the pressure and enthalpy values of the main mass flow caused by the expansion cooling device are substantially at the saturation curve of the enthalpy / pressure diagram.

In particular, in order to prevent the refrigerant compressor unit from sucking in refrigerant with liquid components at the suction connection, it is preferably provided that the refrigerant enters into the suction connection of the refrigerant compressor unit incoming refrigerant can be heated by a heat exchanger connected upstream of this. By means of such a heat exchanger, the refrigerant to be sucked can be heated to such an extent that essentially liquid components are excluded, so that this refrigerant can be designated as overheated.

The heat exchanger could be supplied in a variety of ways heat.

An advantageous solution provides that the heat exchanger removes heat from the high-pressure side heat exchanger exiting total mass flow, so that the exiting from the high-pressure side heat exchanger, but still heated total mass flow can be used to heat the refrigerant entering the refrigerant compressor unit, while still cooling the total mass flow in return takes place.

Further features and advantages of the invention are the subject of the following description and the drawings of some embodiments.

Figur 1

eine schematische Darstellung eines Verrohrungsschemas eines ersten Ausführungsbeispiels einer erfindungsgemäßen Kälteanlage;

Figur 2

eine schematische Darstellung des Drucks [P] über der Enthalpie [h] bei dem ersten Ausführungsbeispiel der erfindungsgemäßen Lösung für einen erfindungsgemäßen überkritischen Kreisprozess;

Figur 3

eine Darstellung ähnlich Figur 1 eines zweiten Ausführungsbeispiels einer erfindungsgemäßen Kälteanlage;

Figur 4

eine Darstellung ähnlich Figur 1 eines dritten Ausführungsbeispiels einer erfindungsgemäßen Kälteanlage und

Figur 5

eine Darstellung ähnlich Figur 1 eines vierten Ausführungsbeispiels einer erfindungsgemäßen Kälteanlage.

In the drawing show:

FIG. 1

a schematic representation of a Verrohrungsschemas a first embodiment of a refrigeration system according to the invention;

FIG. 2

a schematic representation of the pressure [P] on the enthalpy [h] in the first embodiment of the inventive solution for a supercritical cycle according to the invention;

FIG. 3

a representation similar to Figure 1 of a second embodiment of a refrigeration system according to the invention;

FIG. 4

a representation similar to Figure 1 of a third embodiment of a refrigeration system according to the invention and

FIG. 5

a representation similar to Figure 1 of a fourth embodiment of a refrigeration system according to the invention.

A first exemplary embodiment of a refrigeration system according to the invention, illustrated in FIG. 1, comprises a refrigerant circuit denoted as a whole by 10, in which a refrigerant compressor unit designated as a whole is arranged, which in the exemplary embodiment illustrated comprises a plurality of individual refrigerant compressors, for example four refrigerant compressors.

Each of the refrigerant compressor 14 has a port 16 on the suction side and a port 18 on the pressure side, wherein all suction-side ports 16 are combined to form a suction port 20 of the refrigerant compressor unit 12 and all pressure-side ports 18 are combined to form a pressure port 22 of the refrigerant compressor unit 12.

All the refrigerant compressors 14 work in parallel with this, but it is possible to vary the compressor capacity of the refrigerant compressor unit 12 in that individual refrigerant compressors 14 operate and some do not work.

Furthermore, it is possible to vary the compressor power of the refrigerant compressor unit 12 by a variable-speed control of the individual operating refrigerant compressor 14.

In addition, each of the refrigerant compressors 14 also has an additional connection 24, wherein all auxiliary connections 24 of the refrigerant compressors are combined to form an additional suction connection 26 of the refrigerant compressor unit 12.

The refrigerant drawn via the auxiliary suction port 26 from the refrigerant compressor unit 12 is also compressed therefrom to high pressure and, together with the suction port 20 sucked and high-pressure compressed refrigerant at the pressure port 22 of the refrigerant compressor unit 12 from.

The compressed to high pressure refrigerant at the pressure port 22 of the refrigerant compressor unit 12 forms a total mass flow G and this flows through a high-pressure side heat exchanger 30, through which a cooling of the high-pressure compressed refrigerant.

Depending on whether a subcritical cyclic process or a supercritical cyclic process is present, the cooling of the compressed high-pressure refrigerant in the heat exchanger 30 is the same or merely cooling to a lower temperature, wherein the refrigerant remains in the gas phase.

If carbon dioxide, that is CO ₂ , is used as the refrigerant, usually a supercritical cyclic process is present under normal ambient conditions, in which only a cooling takes place to a temperature which corresponds to an isotherm running outside the dew and boiling curve or saturation curve, so that none Liquefaction of the refrigerant occurs.

In contrast, a subcritical cycle process provides that the heat exchanger 30 cools to a temperature that corresponds to an isotherm passing through the dew and boiling or saturation curves of the refrigerant.

The cooled by the heat exchanger 30 refrigerant is subsequently expanded via a pressure line 31 by an expansion cooling means 32 representing an expansion valve 32, for example, an expansion valve to an intermediate pressure PZ, which corresponds to a the tau and boiling curve or saturation curve of the refrigerant passing isotherms.

Thus, the entering into the expansion member 32 and coming from the heat exchanger 30 total mass flow G is placed in a thermodynamic state in which a main mass flow H is in the form of liquid refrigerant and an additional mass flow Z in the form of gaseous refrigerant. Both mass flows are collected in a designated as a collector 34 reservoir and separated from each other, and the additional mass flow Z is a via the collector 34 to the Zusatzsauganschluss 26 extending suction line 36 through the refrigerant compressor unit 12th aspirated, wherein the intermediate pressure PZ in the collector 34 can be set by the delivery capacity of the refrigerant compressor unit 12 available at the additional suction connection 26.

Preferably, an adjustment of the intermediate pressure PZ to a pressure of less than 40 bar, to interpret the following on the collector 34 line and component system of the refrigerant circuit 10 to a pressure of less than 40 bar.

To maintain the intermediate pressure PZ at a level below 40 bar preferably a control unit 40 is provided which detects the intermediate pressure PZ in the collector with a pressure sensor 42 and is also able to connect the individual auxiliary ports 24 of the individual refrigerant compressor 14 to the Zusatzsauganschluss 26 or not switch on.

For example, the refrigerant compressors 14 may correspond to those of German patent application 10 2005 009 173.3 be formed and, for example, be formed as a suction-side connections of one of a plurality of cylinders of the respective refrigerant compressor 14, wherein this cylinder can either be used for sucking refrigerant from the additional mass flow Z via the Zusatzsauganschluss 26 or for sucking refrigerant from the suction port 20 of Refrigerant compressor unit 12 supplied expanded main mass flow.

After the collector 34 there is a division of the main mass flow H consisting of liquefied refrigerant into a normal cooling mass flow N, which is supplied to at least one normal-cooling expansion element 50 or two normal-cooling expansion devices 50a, 50b and at least one normal-cooling heat exchanger 52 connected downstream of the respective normal-cooling expansion element 50.

By the respective Normalalkühlpansionsorgan 50, an expansion of the refrigerant of the normal cooling mass flow N from the intermediate pressure PZ to low pressure PN, wherein a cooling of the refrigerant in the normal cooling mass flow N takes place in a known manner by this expansion, which opens the possibility to absorb heat in the normal cooling heat exchanger 52 , which causes an enthalpy increase.

The normalized cooling mass flow N expanded to low pressure PN is supplied via a suction line 54 to the suction port 20 of the refrigerant compressor unit 12 and compressed by the latter to high pressure PH.

From the main mass flow H, however, not only the normal cooling mass flow N but also a total frozen mass flow TG is formed, which is supplied to a deep-freeze cooling device 62.

By Tiefkühplexionskühleinrichtung 62, an expansion of Tiefkühlgesamtmassenstroms TG takes place on a Tiefkühlzwischendruck PTZ, so that arise from the consisting of liquid refrigerant Tiefkühlgesamtmassenstrom TG a Tiefkühlhauptmassenstrom TH at a below the temperature of Tiefkühlgesamtmassenstroms TG temperature and a Tiefkühlzusatzmassenstrom TZ from vaporous refrigerant.

The main cooling mass flow TH and the auxiliary cooling mass flow TZ are separated from one another in a deep-cooling expansion cooling device 62 and designed as a collector 64, wherein the Tiefkühlzusatzmassenstrom TZ is discharged via a 64 leading from the collector 64 to a mixer 66 discharge line.

The mixer 66 is preferably arranged in the suction line 54 and mixes the frozen additional mass flow TZ with the expanded normal cooling mass flow N from the at least one normal cooling heat exchanger 52, so that then both the Tiefkühlzusatzmassenstrom TZ and the expanded normal mass flow N mixed with each other are fed to the suction port 20 of the refrigerant compressor unit 12 ,

The main cooling main mass flow TH collecting in the collector 64 is then supplied to at least one deep-freeze PTN and supplied to the respective deep-freeze heat exchanger 72 which is connected to the respective at least one deep-freeze expansion element 70, in which the main bulk cooling TH flow cooled by the expansion is able to to absorb heat by increasing the enthalpy at cryogenic temperatures.

The frozen main mass flow TH expanded to the low-pressure low-pressure PTN is fed via a freezer heat exchanger 72 connected to a Tiefkühlsaugleitung 74 a deep-freeze unit 82, which for example also includes a plurality of deep-freeze compressors 84, the individual deep-freeze compressors 84 are switchable depending on the required compressor power.

The deep-freeze compressors 84 also each have a suction-side connection 86 and a pressure-side connection 88, wherein the suction-side connections 86 are combined to form a suction connection 90 of the deep-freeze compressor unit 82 and the pressure-side connections 88 are combined to form a pressure connection 92 of the deep-freeze compressor unit 82.

The suction port 90 of the deep-freeze compressor unit 82 is connected to the deep-freeze suction line 74, while the pressure connection 92 of the deep-freeze compacting unit 82 is connected to a deep-freeze discharge line 94, which is guided to the mixer 66.

The mixer 66 mixes not only the normalized air mass flow N expanded to low pressure PN, the frozen auxiliary mass flow TZ expanded to the intermediate deepfreeze pressure PTZ, but also the main low-pressure mass flow TH condensed to a deep freeze pressure PTH from the deepfreeze compressor unit 82, so that all three mass flows N, TZ and TH correspond to the Suction port 20 of the refrigerant compressor unit 12 at the low pressure PN, which corresponds to the suction pressure at the suction port 20, fed and compressed by the refrigerant compressor unit 12 to high pressure PH.

The supercritical cycle corresponding to the first embodiment is shown in FIG.

The refrigerant present at the suction connection 20 of the refrigerant compressor unit 12 corresponds to the state of the point ZA in FIG. 2. A compression of the refrigerant by the refrigerant compressor unit 12 leads to an increase in pressure with a small enthalpy increase and thus to the thermodynamic state ZB in FIG.

Subsequently, starting from the condition ZB, a cooling of the refrigerant compressed to high pressure PH is maintained while maintaining the high pressure PH in the heat exchanger 30, so that subsequently the refrigerant is in the thermodynamic state ZC, wherein the thermodynamic state ZC above the saturation curve or thawing and boiling line 110 for the refrigerant, in this case carbon dioxide, is located, so that in the thermodynamic state ZC the refrigerant is still gaseous.

By means of the expansion cooling device 32, starting from the state ZC, an isenthalpic expansion of the refrigerant in an expansion element or the almost isentropic expansion takes place in an expander to the intermediate pressure PZ and thus into a thermodynamic state corresponding to the point ZD, which represents a mixture of a liquid phase and a gas phase , wherein in the collector 34, the liquid phase forms the main mass flow H, while the gas phase forms the additional mass flow Z.

By evaporating refrigerant to form the additional mass flow Z, which is discharged via the suction line 36 from the collector 34, the main mass flow H reaches a thermodynamic state corresponding to the point ZE with decrease of the enthalpy h in the range of the saturation curve or boiling line, while the additional mass flow Z achieves the thermodynamic state ZF due to enthalpy increase due to enthalpy removal at the main mass flow H, which lies in the region of the saturation curve or saturated steam line or near the saturation curve or saturated steam line, from which the additional mass flow Z is again compressed to the high pressure PH, by the additional mass flow Z is sucked in via the additional suction port 26 of the refrigerant compressor unit 12 and compressed to the high pressure PH.

The refrigerant from the main mass flow H is expanded from the state ZE by isenthalp relaxation to the low pressure PN, once in the form of the normal cooling air flow N by the at least one Normalalkühpansionsorgan 50 and another time by the Tiefkühplexionskühleinrichtung 62, wherein the Tiefkühlungpischions PTZ automatically to the pressure level of Low pressure PN at the suction port 20 of the refrigerant compressor unit 12 sets, unless special measures to change this pressure are taken.

Thus, the refrigerant reaches the main mass flow H once as a normal cooling mass flow N and once as Tiefkühlgesamtmassenstrom TG the thermodynamic state corresponding to the point ZG in Figure 2.

In the case of the normal cooling mass flow N, an enthalpy increase takes place in the normal cooling heat exchanger, so that the refrigerant of the normal cooling mass flow N reaches a preferably superheated state after leaving the at least one normal cooling heat exchanger 52.

In the case of the total frozen mass flow TG, the deep-cooler expansion cooling device 62 and the subsequent collector 64 form a division into a liquid phase, which forms the main cooling mass flow TH, which passes into the thermodynamic state ZH in the region of the saturation curve or boiling line through enthalpy discharge, while the gas phase forms the additional frozen mass flow TZ which is supplied via the discharge line 68 to the suction port 20 of the refrigerant compressor unit 12, wherein the Tiefkühlzusatzmassenstrom TZ starting from the thermodynamic State ZG by enthalpy removal of the main cooling mass flow TH undergoes an enthalpy increase, so that this reaches a thermodynamic state in the region of the saturation curve or saturated steam line or near the saturation curve or saturated steam line in Figure 2.

The at least one normal-cooling expansion element 50 and the subsequent normal-cooling heat exchanger 52 form a normal cooling stage 100, the deep-cooling expansion cooling device 62, the collector 64, the discharge line 68, the at least one deep-cooling expansion element 70, the deep-freeze heat exchanger 72 and the deep-freeze compressor unit 82 form a deep-freezing stage integrated in the refrigerant circuit 10 102, which is traversed by a part of the main mass flow H, namely the Tiefkühlgesamtmassenstrom TG, while the normal cooling 100 flows through the normal cooling mass flow N, where ultimately both the normal cooling mass flow N and the Tiefkühlgesamtmassenstrom TG again at low pressure PN via the suction port 20 of the refrigerant compressor unit Sucked 12 and compressed to high pressure PH, wherein the pressure connection 22 of the refrigerant compressor unit 12 leaving total mass flow G not only from the normal cooling enstrom N and the Tiefkühlgesamtmassenstrom TG, but additionally includes the additional mass flow Z, which is received by the refrigerant compressor unit via the Zusatzsauganschluss 26.

Starting from the state ZH, the refrigerant of the main cooling mass flow TH is supplied to the at least one deep-free expansion element 70 and undergoes an isenthalpic expansion to the deep-freeze pressure PTN in it, thus reaching the thermodynamic state ZI in FIG.

In this thermodynamic state ZI in FIG. 2, the main cooling mass flow TH can be absorbed by enthalpy increase at the freezing temperature in the at least one deep-freeze heat exchanger 72, thereby achieving the thermodynamic state ZJ in FIG.

In the simplest case, the state ZJ in FIG. 2 is achieved by the overheating control of the deep-freeze expansion element 70 in the deep-freeze heat exchanger 72. In the real application, an additional heat input in the suction line 74 is observed. Another possibility provides one or more heat exchangers between the suction line 74 and the liquid line, starting from the point ZI in FIG.

Starting from this thermodynamic state ZJ, the main cooling main mass flow TH expanded to the low-pressure low-pressure PTN is compressed by the deep-freeze compressor unit 82 to the suction pressure at the suction connection 20 of the refrigerant compressor unit 12 corresponding to a high-pressure deep-pressure PTH, an enthalpy increase being associated with this compression so that the thermodynamic state ZK in FIG is reached.

By mixing the concentrated to deep freeze pressure PTH Tiefkühlhauptmassenstrom TH in the mixer 66 with the lower temperature having normal mass flow N at low pressure PN and also a lower temperature Tiefkühlzusatzmassenstrom TZ in the mixer 66 takes place Enthalpy decrease of the deep freeze high pressure PTH deep freezing main mass flow TH, so that of all three mass flows TH, N, TZ of the thermodynamic state ZA is reached, starting from which a compression takes place in the refrigerant compressor unit 12 in order to achieve the thermodynamic state ZB in Figure 2.

In a second embodiment of a refrigeration system according to the invention, shown in Figure 3, those parts which are identical to those of the first embodiment, provided with the same reference numerals, so that with respect to the description of the same fully incorporated by reference to the comments on the first embodiment.

In contrast to the first embodiment, in the second embodiment, between the suction line 36 and the suction port 20 of the refrigerant compressor unit 12, a connecting line 120 is provided with a throttle member 122 provided therein, which is controllable via the controller 40 '.

This makes it possible to supply a portion of the additional mass flow Z via the connecting line 120 to the suction port 20 of the refrigerant compressor unit 12, preferably when the existing flow rate at the Zusatzsauganschluss 26 is exhausted and controlled by the control 40 intermediate pressure PZ exceeds a set limit , This is particularly the case in particular, but not constantly occurring operating conditions of the case in which the additional mass flow Z increases very greatly, so that this would provide an additional compressor delivery rate in the refrigerant compressor unit 12 would be provided, which is usually not needed. For this reason, a possibility is created under the operating efficiency and the specific cooling capacity per delivery volume to keep the intermediate pressure PZ below 40 bar under all operating conditions.

With regard to the thermodynamic states that have passed through, the second exemplary embodiment fully corresponds to the first exemplary embodiment, so that reference is made in full to the detailed explanations in the first exemplary embodiment.

In a third embodiment, shown in Figure 4, is provided in a modification to the second embodiment that the refrigerant compressor 14 are not provided with additional connections 24, so that the refrigerant compressor unit 12 has no Zusatzsauganschluss 26, but the entire additional mass flow Z via the connecting line 120 the Suction port 20 is supplied, wherein the throttle member 122 is to be adjusted so that the intermediate pressure PZ is higher than the low pressure PN, which is present at the suction port 20 of the refrigerant compressor unit 12.

Incidentally, with regard to the mode of operation of the third exemplary embodiment according to FIG. 4, full reference is made to the comments on the first and second exemplary embodiments.

In a fourth exemplary embodiment, illustrated in FIG. 5, a heat exchanger element 130a is provided in the suction line 54 between the mixer 66 and the suction connection 20 in a modification of the second exemplary embodiment, which is coupled to a heat exchanger element 130b in the pressure line 31 that is connected between the heat exchanger 30 and the expansion cooling device 32 is arranged and flowed through by the total mass flow G, so that, depending on specific situations by ambient temperatures and partial load conditions, it is possible to heat the refrigerant supplied to the suction port 20 so far that it is free of liquid components.

Incidentally, with regard to the description of the fourth embodiment, reference is made in full to the comments on the first and second embodiments.

Claims (32)

A refrigeration system comprising a refrigerant circuit (10) in which a total mass flow (G) of a refrigerant is guided, a high pressure side refrigerant cooling heat exchanger (30) arranged in the refrigerant circuit (10), an expansion cooling device (32) arranged in the refrigerant circuit (10) active state, the total mass flow (G) of the refrigerant cools and thereby produces a main mass flow (H) of liquid refrigerant and an additional mass flow (Z) of gaseous refrigerant, a reservoir (34) for the main mass flow (H), at least one a normal cooling mass flow (N) from the reservoir-taking normal cooling stage (100) with a Normalalkühpansionsorgan (50) and this downstream, low pressure side, cooling capacity for normal cooling available normal cooling heat exchanger (52), a Tiefkühlgesamtmassenstrom (TG) from the reservoir (34) taking out deep freezing stage (102) a Tiefkühlexpansi onsorgan (70) and a downstream, cooling capacity for deep freezing Tiefkühlwärmetauscher (72) and with a deep freeze heat exchanger (72) downstream of the freezer compressor unit (82), and at least one in the refrigerant circuit (10) arranged refrigerant compressor unit (12) containing the refrigerant of the main mass flow (H) of the additional mass flow (Z) compressed to high pressure (PH), characterized in that the freezing stage (102) for further cooling the Tiefkühlgesamtmassenstroms (TG) a Tiefkühplexionskühleinrichtung (62) which cools the Tiefkühlgesamtmassenstrom (TG) in the active state and thereby generates a Tiefkühplexionsorgan (70) supplied Tiefkühlhauptmassenstrom (TH) and a Tiefkühlzusatzmassenstrom (TZ). Refrigeration system according to claim 1, characterized in that in the Tiefkühplexionskühlinrichtung (62) a Tiefkühlzwischendruck (PTZ) is present, which is between the intermediate pressure (PZ) of the expansion cooling device (32) and a suction pressure (PTN) of the deep-freeze compressor unit (82). Refrigeration system according to claim 2, characterized in that in the Tiefkühlexpansionskühleinrichtung (62) of the intermediate cryogenic pressure (PTZ) is at least about 2 bar lower than the intermediate pressure (PZ) of the expansion cooling device (32). Refrigeration system according to claim 2 or 3, characterized in that in the Tiefkühplexionskühlinrichtung (62) of the intermediate cryogenic pressure (PTZ) is at least about 2 bar higher than the suction pressure (PTN) of the deep-freeze compressor unit (82). Refrigeration plant according to one of claims 2 to 4, characterized in that in the Tiefkühplexionskühlinrichtung (62) an intermediate deep-pressure (PTZ) is present in a middle region of the pressure difference between the intermediate pressure (PZ) in the expansion cooling device and the suction pressure (PTN) of the frozen compactor unit (82) lies. Refrigeration system according to claim 5, characterized in that in the Tiefkühplexionskühlinrichtung (62) an intermediate deep-pressure (PTZ) is present, which in a middle third of a divided into three thirds pressure difference between the intermediate pressure (PZ) in the expansion cooling device (32) and the suction pressure (PTN ) of the frozen compactor unit (82). Refrigeration system according to one of the preceding claims, characterized in that in this the Tiefkühlzusatzmassenstrom (TZ) of the refrigerant compressor unit (12) is supplied. Cooling system according to claim 7, characterized in that in this the Tiefkühlzusatzmassenstrom (TZ) is fed to a suction port (20) of the refrigerant compressor unit (12). Refrigeration system according to claim 8, characterized in that in this the Tiefkühlzusatzmassenstrom (TZ) pressure-regulating free to the suction port (20) is supplied. Refrigeration system according to claim 8 or 9, characterized in that the intermediate cryogenic pressure (PTZ) in the region of the low pressure (PN) at the suction port (20) of the refrigerant compressor unit (12). Refrigeration system according to one of claims 7 to 10, characterized in that the Tiefkühlzusatzmassenstrom (TZ) together with the low-pressure (PN) expanded normal cooling mass flow (N) of the refrigerant compressor unit (12) is supplied. Cooling system according to one of the preceding claims, characterized in that the deep-freeze main mass flow (TH) compressed by the deep-freeze compressor unit (82) is supplied to the refrigerant compressor unit (12) from this. Cooling system according to claim 12, characterized in that from this the deep-freeze main mass flow (TH) compressed by the deep-freeze compressor unit (82) is supplied to the expanded normal air mass flow (N) to a suction port (20) of the refrigerant compressor unit (12). Cooling system according to claim 12 or 13, characterized in that from this of the deep-freeze compressor unit (82) compressed Tiefkühlhauptmassenstrom (TH), the Tiefkühlzusatzmassenstrom (TZ) and the expanded normal cooling mass flow (N) mixed together the suction port (20) of the refrigerant compressor unit (12) be supplied. Refrigeration system according to one of the preceding claims, characterized in that the Tiefkühplexionskühleinrichtung (62) reduces the enthalpy (ZI) of the Tiefkühlhauptmassenstroms (TH) by at least 10% compared to the enthalpy (ZG) of Tiefkühlgesamtmassenstroms (TG). Refrigeration system according to claim 15, characterized in that the Tiefkühplexionskühleinrichtung (62) reduces the enthalpy of the Tiefkühlhauptmassenstroms (TH) by at least 20%. Refrigeration system according to one of the preceding claims, characterized in that the Tiefkühplexionskühleinrichtung (62) generates the Tiefkühlhauptmassenstrom (TH) in a thermodynamic state (ZI), the pressure and enthalpy values are lower than those (ZG) of the normal cooling mass flow (N). Refrigeration plant according to one of the preceding claims, characterized in that the pressure and enthalpy values of the main cooling main flow (TH) caused by the deep-free expansion cooling means (62) are close to the saturation curve (110) in the enthalpy / pressure diagram. Cooling system according to claim 18, characterized in that the pressure and enthalpy values of the main cooling main flow (TH) caused by the deep-freeze cooling means (62) lie substantially on the saturation curve (110) of the enthalpy / pressure diagram. Refrigeration system according to one of the preceding claims, characterized in that the expansion cooling device (32) has an expansion element for expansion of the total mass flow (G) to an intermediate pressure (PZ) and that a maximum value of the intermediate pressure (PZ) is adjustable. Refrigeration system according to one of the preceding claims, characterized in that the intermediate pressure (PZ) is adjustable to a maximum value of 40 bar or less. Refrigeration system according to one of the preceding claims, characterized in that the intermediate pressure (PZ) by supplying at least a portion of the additional mass flow (Z) to a Zusatzsauganschluss (26) of the refrigerant compressor unit (12) is adjustable. Refrigeration system according to one of the preceding claims, characterized in that the intermediate pressure (PZ) by supplying at least a portion of the additional mass flow (Z) to a suction port (20) of the refrigerant compressor unit (12) is adjustable. Refrigeration system according to claim 22 or 23, characterized in that a controller (40) is provided, which feeds the additional mass flow (Z) either the Zusatzsauganschluss (26) or this and in parts the suction port (20) of the refrigerant compressor unit (12). Refrigeration plant according to one of the preceding claims, characterized in that the expansion cooling means (32) reduces the enthalpy of the main mass flow (H) by at least 10% compared to the enthalpy of the total mass flow (G). Refrigeration system according to claim 25, characterized in that the expansion cooling means (32) reduces the enthalpy of the main mass flow (H) by at least 20%. Refrigeration system according to one of the preceding claims, characterized in that the expansion cooling device (32) is active in a supercritical operation of the refrigeration system. Refrigeration plant according to one of the preceding claims, characterized in that the expansion cooling means (32) generates the main mass flow (H) in a thermodynamic state whose pressure and enthalpy values are lower than those of a maximum of the saturation curve (110). Refrigeration plant according to claim 28, characterized in that the pressure and enthalpy values of the main mass flow (H) caused by the expansion cooling means (32) are close to the saturation curve (110) in the enthalpy / pressure diagram. Cooling system according to claim 29, characterized in that the pressure and enthalpy values of the main mass flow (H) caused by the expansion cooling device (32) lie substantially on the saturation curve (110) of the enthalpy / pressure diagram. Refrigeration plant according to one of the preceding claims, characterized in that in the suction port (20) of the refrigerant compressor unit (12) entering refrigerant can be heated by a heat exchanger (130) connected upstream of this. Cooling system according to claim 31, characterized in that the heat exchanger (130) removes heat from the total mass flow (G) emerging from the high-pressure side heat exchanger (130).

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