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WO2011054396A1 - Système de réfrigération et procédé de fonctionnement d'un système de réfrigération - Google Patents

Système de réfrigération et procédé de fonctionnement d'un système de réfrigération Download PDF

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Publication number
WO2011054396A1
WO2011054396A1 PCT/EP2009/064769 EP2009064769W WO2011054396A1 WO 2011054396 A1 WO2011054396 A1 WO 2011054396A1 EP 2009064769 W EP2009064769 W EP 2009064769W WO 2011054396 A1 WO2011054396 A1 WO 2011054396A1
Authority
WO
WIPO (PCT)
Prior art keywords
refrigerant
refrigerating system
branch
compressor unit
collecting container
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.)
Ceased
Application number
PCT/EP2009/064769
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English (en)
Inventor
Peter Leweke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Carrier Corp
Original Assignee
Carrier Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Carrier Corp filed Critical Carrier Corp
Priority to EP09755868.8A priority Critical patent/EP2496894B1/fr
Priority to PCT/EP2009/064769 priority patent/WO2011054396A1/fr
Priority to DK09755868.8T priority patent/DK2496894T3/en
Publication of WO2011054396A1 publication Critical patent/WO2011054396A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • 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
    • 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
    • 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
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
    • F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure
    • 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
    • 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
    • F25B2400/13—Economisers
    • 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
    • F25B2400/23—Separators
    • 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
    • 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
    • F25B2700/21152—Temperatures of a compressor or the drive means therefor at the discharge side of the compressor

Definitions

  • the invention relates to a refrigerating system and to a method of operating a refrigerating system.
  • vapour compression refrigerating systems are well-known. It is also known for refrigerating systems to comprise a normal refrigeration portion and a freezer portion. For example, a supermarket refrigerating system may provide for the cooling of both the sales furniture having a normal refrigeration level and the sales furniture having a freezing temperature level.
  • so-called booster systems are known that employ a first compressor for the normal refrigeration portion of the refrigeration system and a second compressor unit for the freezing portion of the refrigeration system, wherein the compressed refrigerant from the pressure side of the second compressor is supplied to the suction side of the first compressor.
  • a refrigerating system comprises a refrigerant circuit having the following elements: a first compressor unit, a condenser/gas cooler, a collecting container, a normal refrigeration branch coupled between the collecting container and a suction side of the first compressor unit, with the normal refrigeration branch comprising a first expansion device and a first evaporator, and a freezing branch coupled between the collecting container and the suction side of the first compressor unit, with the freezing branch comprising a second expansion device, a second evaporator, a second compressor unit and a desuperheating device, wherein the refrigerant circuit further comprises refrigerant conduits for connecting said elements and for circulating a refrigerant therethrough.
  • a method of operating a refrigerating system comprises circulating a refrigerant through a refrigerant circuit comprising a first compressor unit, a condenser/gas cooler, a collecting container, a normal refrigeration branch having a first expansion device and a first evaporator, and a freezing branch having a second expansion device and a second evaporator, and desuperheating the refrigerant in the freezing branch by providing a second compressor unit and a desuperheating device in the freezing branch.
  • Fig. 1 shows a connection diagram of a refrigerating system according to an exemplary embodiment of the invention.
  • the refrigerant circuit of the refrigerating system 2 comprises, in flow direction of the refrigerant, a first compressor unit 4 having three compressors connected in parallel, a pressure conduit 34 leading to a condenser/gas cooler 6, an intermediate expansion device 8, and a collecting container 10 in which liquid refrigerant collects in the lower liquid refrigerant portion and gaseous refrigerant collects in the upper gaseous refrigerant portion.
  • a cooling branch supply conduit 18 runs liquid refrigerant through a heat exchanger 20 and supplies the liquid refrigerant to a normal refrigeration branch and a freezing branch.
  • the normal refrigeration branch includes a first expansion device 22 and a first evaporator 24, from which the refrigerant reaches the first compressor unit 4 via normal refrigeration branch outlet conduit 36.
  • the freezing branch includes, in flow direction of the refrigerant, a second expansion device 26, a second evaporator 28, a second compressor unit 30 and a desuperheating device 32, from which the refrigerant reaches the first compressor unit 4 via freezing branch outlet conduit 38.
  • the refrigerant circuit further comprises a cooling branch bypass conduit 16, which is coupled to the gaseous refrigerant portion of the collecting container 10 via a gaseous refrigerant expansion device 12 and to the liquid refrigerant portion of the collecting container 10 via a liquid refrigerant expansion device 14.
  • the cooling branch bypass conduit 16 runs through the heat exchanger 20 and is connected to the first compressor unit 4.
  • the heat exchanger 20 establishes a heat exchange relationship between the cooling branch bypass conduit 16 and the cooling branch supply conduit 18, i.e. between the refrigerant in the cooling branch bypass conduit 16 and the refrigerant in the cooling branch supply conduit 18.
  • the refrigerant is compressed by the first compressor unit 4, through which the refrigerant assumes a temperature in the pressure conduit 34 that greatly exceeds common ambient air temperatures.
  • the condenser/gas cooler 6 the refrigerant is cooled down against a secondary medium.
  • the secondary medium is air.
  • other secondary media such as water or air enriched with water particles, may also be used.
  • the condenser/gas cooler is referred to as a gas cooler, as the refrigerant leaves the gas cooler 6 in a gaseous phase.
  • a condensation may take place in the condenser/gas cooler 6, such that this refrigerant circuit element is referred to as a condenser.
  • the refrigerant is expended to an intermediate pressure level in the intermediate expansion device 8.
  • the C0 2 is present partially in its gaseous phase and partially in its liquid phase, with the liquid refrigerant collecting in the lower liquid refrigerant portion of the collecting container 10 and the gaseous refrigerant collecting in the upper gaseous refrigerant portion of the collecting container 10.
  • Liquid refrigerant is flown from the liquid refrigerant portion of the collecting container 10 into the cooling branch supply conduit 18 in order to supply the normal refrigeration branch and the freezing branch with refrigerant.
  • the refrigerant passes through the heat exchanger 20, where it is cooled further down from the temperature assumed after the intermediate expansion device 8, as will be described in more detail later. After the heat exchanger 20, the refrigerant supply conduit 18 branches off into the normal refrigeration branch and the freezing branch.
  • the refrigerant is further expanded by the first expansion device 22, through which the pressure and the temperature of the refrigerant are further reduced.
  • the symbol of the first evaporator 24 stands for a plurality of cold consumers at a normal refrigeration level, for example a plurality of refrigerated sales shelves in a supermarket.
  • air is cooled against the refrigerant leaving the first expansion device 22.
  • the cooled air keeps the contents of the refrigerated space of the cold consumers cold.
  • the first expansion device 22 is controlled in a way such that the refrigerated space temperature of the cold consumers stays constant.
  • a typical desired temperature is between 5 °C and 10 °C.
  • the refrigerant exits the first evaporator 24 at about 0 °C. From the outlet of the first evaporator 24, the refrigerant reaches the suction side of the first compressor unit 4 via normal refrigeration branch outlet conduit 36.
  • the first evaporator 24 may also be a single cold consumer, such as a single cooling shelve.
  • the refrigerant is flown to the second expansion device 26, through which the refrigerant is expanded to a pressure and temperature lower than the pressure and temperature after the first expansion device 22. Accordingly, the second evaporator 28 cools down air to a freezing temperature, such that a freezing functionality is achieved.
  • the evaporator 28 stands for one or a plurality of cold consumers, such as an array of freezers in a supermarket. The air space of these freezers is cooled down to a below 0 °C temperature.
  • the refrigerant is flown to a second compressor unit 30, where the refrigerant is compressed, which leads to an increase of the refrigerant temperature, to approximately 70-80 °C.
  • the second compressor unit 30 is shown to have 3 compressors, but may be comprised of a smaller or greater number.
  • the refrigerant is then cooled against a secondary medium in the desuperheat- ing device 32.
  • the secondary medium may be air, water, air enriched with water particles, a brine or any other suitable secondary medium.
  • the refrigerant is brought into a heat exchange relationship with the secondary medium, such that the refrigerant is desuperheated.
  • the desuperheating device may be placed within a machine room of the refrigerating system or at an outdoor location. In the case of the secondary medium being air, the refrigerant is cooled down to a temperature corresponding to and some degrees above the respective ambient temperature. In this way, a portion of the heat added to the refrigerant in the evaporator 28 is withdrawn from the refrigerant in the desuperheating device 32.
  • the desuperheated refrigerant is flown through the freezing branch outlet conduit 38 into the cooling branch bypass conduit 16 - after the heat exchanger 20 - and from there to the suction side of the first compressor unit 4.
  • the freezing branch outlet conduit 38 may equally be joined with the normal refrigeration branch outlet conduit 36 or may be coupled directly to the suction side of the first compressor unit 4.
  • the second compressor unit 30 compresses the refrigerant to a pressure substantially equal to the pressure of the refrigerant after leaving the first expansion device 22.
  • the refrigerant portions in the normal refrigeration branch outlet conduit 36 and the freezing branch outlet conduit 38 do not exhibit substantial pressure differences, such that a mixing of these refrigerant portions without the occurrence of counter-flow in one of the two outlet conduits is achieved.
  • this pressure correspondence is not mandatory.
  • the refrigerant leaves the first evaporator 24 of the normal refrigeration branch at a temperature of around 0°C, whereas the the refrigerant leaves the desuperheating device 32 at a temperature of ca. 20-35°C. Accordingly, the refrigerant at the suction side of the first compressor unit 4 has a resulting temperature in between the respective branch outlet temperatures.
  • the temperature of the refrigerant at the suction side of the first compressor unit 4 determines the temperature of the refrigerant at the pressure side of the first compressor unit 4, assuming a given compressor performance.
  • the temperature of the refrigerant in the pressure conduit 34 is a critical parameter, particularly because the first compressor unit 4 and the condenser/gas cooler 6 have a maximum operating temperature. In order for the system to operate safely, the temperature of the refrigerant in the pressure conduit 34 cannot exceed a predetermined threshold.
  • a temperature sensor (not shown) in the pressure conduit senses the temperature of the refrigerant, such that the temperature can be monitored over time and an exceeding of the predetermined threshold value can be avoided.
  • the temperature sensor may be placed at the suction side of the first compressor unit 32, with the corresponding temperature in the pressure conduit 34 being calculated from a given first compressor unit performance.
  • a pressure sensor may be arranged in the pressure conduit 34, with the temperature or the refrigerant being deduced from known refrigerant properties.
  • the refrigerant reaching the pressure conduit 34 carries inherently less heat than in a refrigerating system without the desuperheating device 32. Accordingly, more degrees of freedom are given to a system designer due to the presence of the desuperheating device 32. In other words, for the rest of the refrigerating system being identical, the presence of the desuperheating device 34 drastically decreases the probability of the temperature in the pressure conduit 34 reaching a critical value.
  • the cooling branch bypass conduit 16 is provided.
  • refrigerant from the collecting container 10 is flown into the normal refrigeration branch outlet conduit 36.
  • the cooling branch bypass conduit 16 is connected to the gaseous refrigerant portion of the collecting container 10 via the gaseous refrigerant expansion device 12 and to the liquid refrigerant portion of the collecting container 10 via the liquid refrigerant expansion device 14, respectively.
  • the gaseous and liquid refrigerant expansion devices 12 and 14 are controlled separately. Both of these expansion devices expand the refrigerant, such that low temperature refrigerant can be mixed with the refrigerant portions coming from the first evaporator 24 and the desuperheating device 32.
  • the gaseous and liquid refrigerant expansion devices 12 and 14 are operated in a way to control the temperature of the refrigerant in the pressure conduit 34. It is pointed out that it is also possible to have only one of the gaseous refrigerant expansion device 12 and the liquid refrigerant expansion device 14 in place, in order to bring down the refrigerant temperature at the pressure conduit 34.
  • liquid refrigerant is supplied to the normal refrigeration branch and the freezing branch.
  • Gaseous refrigerant also referred to as flash gas
  • the gaseous refrigerant expansion device 12 is primarily operated for introducing unused refrigerant, i.e. refrigerant not used in cold consumers, into the suction side of the first compressor unit 4. Should the introduction of the flash gas not be sufficient for maintaining a desired temperature working point in the pressure conduit 34, the liquid refrigerant expansion device 14 is operated additionally to introduce more unused refrigerant for purposes of reducing the controlled temperature.
  • the exemplary embodiment of Fig. 1 further comprises the heat exchanger 20, which brings the cooling branch supply conduit 18 and the cooling branch bypass conduit 16 into a heat exchange relationship.
  • the heat exchanger is arranged behind the gaseous refrigerant expansion device 12 and the liquid refrigerant expansion device 14, the refrigerant in the cooling branch bypass conduit 16 is at a lower temperature than the refrigerant in the cooling branch supply conduit 18. Therefore, the refrigerant in the cooling branch supply conduit 16 is cooled below the temperature of the refrigerant in the collecting container 10.
  • the refrigerant in the cooling branch bypass conduit 16 may achieve a lowering of the refrigerant temperature in the pressure conduit in two ways.
  • the refrigerant in the cooling branch supply conduit 18 lowers the temperature of the refrigerant in the cooling branch supply conduit 18, such that, if the same amount of thermal energy is absorbed by the refrigerant in the normal refrigeration branch and the freezing branch, the refrigerant reaches the suction side of the first compressor unit 4 at a lower temperature.
  • the refrigerant in the cooling branch bypass conduit itself provides for a reduction of the refrigerant mix at the suction side of the first compressor unit 4. It is also possible that the refrigerant in the normal refrigeration branch and the freezing branch absorbs more thermal energy from the secondary media in the first evaporator 24 and the second evaporator 28 due to its lower evaporator inlet temperature, such that a more effective cooling of the cold consumers is achieved.
  • the heat exchanger 20 may be controllable.
  • the level of heat exchange between the cooling branch supply conduit 18 and the cooling branch bypass conduit 16 may be adaptable. This can be achieved via suitable conduits in the heat exchanger 20, such that the length of the conduits effecting the heat exchange is selectively chosen, for example by providing multiple refrigerant branches in the heat exchanger and according directing of the refrigerant. Accordingly, it can be set by a controller to what extent the available cooling capacity of the refrigerant in the cooling branch bypass conduit is used for the cooling purposes in the first and second evaporators 24 and 28 and to what extent it is directly used for reducing the temperature of the refrigerant mixture at the suction side of the first compressor unit 4.
  • the performance of the desuperheating device 32 may also be adjustable, for example by setting the speed of a fan that blows a secondary medium through the desuperheating device 32 for absorbing thermal energy from the refrigerant or by switching on/off a suitable number of a plurality of fans.
  • a controller or control unit (not shown) is provided, which is connected to the temperature sensor in the pressure conduit 34. Depending on the temperature sensed, the controller controls the one or more of the gaseous refrigerant expansion device 12, the liquid refrigerant expansion device 14, the heat exchanger 20 and the desuperheating device 32.
  • Providing a control unit that controls the gaseous refrigerant expansion device 12 and the liquid refrigerant expansion device 14 only as a response to the refrigerant temperature in the pressure conduit 34 allows for an excellent trade off between control algorithm complexity, control loop stability and control reaction time.
  • the refrigerating system 2 is the refrigerating system of a supermarket.
  • the first evaporator 24 comprises an array of cooling shelves operated between 5°C and 10°C, with the cooling shelves being open for the consumer to conveniently take refrigerated goods, such a dairy products, out of the shelves.
  • the second evaporator 28 comprises an array of freezers operated between -20°C and -15°C, with the freezers being either chest freezers with sliding covers or stand-up freezes with doors. Temperature sensors are provided in the array of cooling shelves as well as in the array of freezers.
  • the first and second expansion devices 22 and 26 are controlled in order provide sufficient refrigerant to the first and second evaporators 24 and 28 in order to maintain the respective desired temperatures. It is also possible that each cold consumer, in the present example each cooling shelf and each freezer, has its own expansion device associated therewith.
  • the mixing temperature of the refrigerant at the suction side of the first compressor unit 4, and therewith in the pressure conduit 34 increases as compared to during business hours.
  • the change in mixing temperature is not as high as in conventional booster systems without desuperheating device.
  • the reason for this is that the temperature difference between the refrigerant exiting the normal refrigeration branch and the refrigerant exiting the freezing branch is drastically reduced by the desuperheating device 32. Accordingly, a ratio change between the two refriger- ant portions of the two branches does not have as much of an effect on the refrigerant temperature in the pressure conduit 34 as in the case without the de- superheating device 32.
  • the control requirements for the refrigerating system 2 as a whole are reduced substantially.
  • the provision of the cooling branch bypass conduit 16 as well as the gaseous refrigerant expansion device 12 and the liquid refrigerant expansion device 14 allows for safely controlling the refrigerating system 2 over a wide range of operating conditions.
  • the desuperheating device 32 it is ensured that a comparatively low level of controlling measures are to be taken in order to keep the system in a desired operating condition.
  • the provision of the efficient temperature reduction functionality via flash gas and liquid refrigerant through the cooling branch bypass conduit 16 allows for very quick response times of the refrigerating system 2 to a change in the operating conditions.
  • the desuperheating device 32 is positioned in the machine room of the refrigerating system 2. Should the refrigerating system 2 not have its own machine room, the desuperheating device may be positioned in a general machine room of the building, for example in a machine room / storage room of the supermarket. By placing the desuperheating device 32 indoors, it is ensured that, even in the winter time, the secondary medium is not at such a low temperature that the refrigerant condenses or partially condenses in the desuperheating device 32. Therefore, stable operating conditions for the refrigerant mixing at the suction side of the first compressor unit 4 and during the compressing operation in the first compressor unit 4 are achieved.
  • the machine room may even be heated by the desuperheating device.
  • the desuperheating device 32 may be positioned at an outdoor location, where a greater reduction of the refrigerant temperature may be achieved than at an indoor location, particularly when the heat exchange with the secondary medium is designed efficiently via a strong secondary medium flow. It is also possible to provide two desuperheating devices, one of which being positioned at an outdoor location and the other one being positioned in the machine room.
  • Suitable ducting with a branching element after the second compressor unit 30 and a reunification of the ducts before the first compressor unit 4, together with suitable means for directing the refrigerant flow, allows for heating the machine room and pre- venting refrigerant condensation in the winter as well as maximum refrigerant temperature reduction outdoors in the summer.
  • Exemplary embodiments of the invention as described above allow for an energy-efficient refrigerating system with low control requirements.
  • the desuper- heating device allows for a desuperheating of the refrigerant against readily available secondary media, i.e. without the consumption of further cooling power.
  • the desuperheating device in the freezing branch makes the refrigerating system more robust by decreasing the sensitivity against operating condition changes, particularly against changes in the ratio of cooling power consumed in the normal refrigeration branch vs. cooling power consumed in the freezing branch. Consequently, not a lot of energy has to be invested in controlling the refrigerating system, as the system deviates slower from a desired operating point. Particularly for large systems with many cold consumers, the control expenses saved are very substantial.
  • the refrigerant circuit further comprises a cooling branch bypass conduit coupled between the collecting container and the suction side of the first compressor unit, wherein the cooling branch bypass conduit is coupled to the collecting container via a bypass conduit expansion device.
  • the provision of the cooling branch bypass conduit and the bypass conduit expansion device allows for an efficient controlling of the refrigerant mix at the suction side of the first compressor unit.
  • the temperature of the refrigerant at the pressure side of the first compressor unit can be held in acceptable limits in a very efficient manner.
  • the refrigerant circuit may further comprise a heat exchanger establishing a heat exchange relationship between the cooling branch bypass conduit and a cooling branch supply conduit coupling the collecting container to the first and second expansion devices.
  • a heat exchanger may be disposed at such a position that the refrigerant in the cooling branch bypass con- duit interacts with the refrigerant in the cooling branch supply conduit before the cooling branch supply conduit branches out into the normal refrigeration branch and the freezing branch. In this way, the cooling performance of both the normal refrigeration branch and the freezing branch is improved. It is, however, possible to effect the heat exchange between the cooling branch bypass conduit and only one of normal refrigeration branch and freezing branch.
  • the refrigerating system further comprises a temperature sensor disposed at one of the suction side of the first compressor unit and a pressure side of the first compressor unit, and a control unit coupled to the temperature sensor and configured to control at least one of the desuperheating device, the bypass conduit expansion device and the heat exchanger.
  • a temperature sensor disposed at one of the suction side of the first compressor unit and a pressure side of the first compressor unit
  • a control unit coupled to the temperature sensor and configured to control at least one of the desuperheating device, the bypass conduit expansion device and the heat exchanger.
  • controllable devices allow for great flexibility and a high number of degrees of freedom when designing the control algorithm of the refrigerating system. In this way, an excellent trade off between control algorithm complexity, control reaction time and energy invested for control purposes can be found. Also, this trade off may be adapted to the particular refrigerating system installation efficiently.
  • the refrigerant circuit comprises an intermediate expansion device disposed between the condenser/gas cooler and the collecting container, such that the collecting container is operated at an intermediate pressure level.
  • the collecting container may comprise a gaseous refrigerant portion and a liquid refrigerant portion, with the refrigerant in operation being separated into gaseous refrigerant in the gaseous refrigerant portion and liquid refrigerant in the liquid refrigerant portion.
  • the separation of refrigerant allows for only supplying refrigerant in one phase to the normal refrigeration branch and the freezing branch, which provides for a better stability and predictability of the refrigerating system.
  • the refrigerant circuit may further comprise a cooling branch supply conduit coupling the liquid refrigerant portion of the collecting container to the first and second expansion devices. In this way, only the liquid refrigerant, which is able to absorb more thermal energy than the gaseous refrigerant, is flown to the cold consumers, which allows for a higher cooling rate at a reference refrigerant flow rate.
  • the refrigerant circuit comprises a cooling branch bypass conduit coupled between the collecting container and the suction side of the first compressor unit, wherein the cooling branch bypass conduit is coupled to the gaseous refrigerant portion of the collecting container via a gaseous refrigerant expansion device.
  • the gaseous refrigerant which is less desirable for cooling purposes in the cold consumers, can be brought to good use for regulating the temperature at the suction side, and therewith at the pressure side, of the first compressor unit.
  • the cooling branch bypass conduit is coupled to the liquid refrigerant portion of the collecting container via a liquid refrigerant expansion device.
  • the refrigerating system further comprises a temperature sensor disposed at one of the suction side of the first compressor unit and a pressure side of the first compressor unit, and a control unit coupled to the temperature sensor and configured to control at least one of the desuperheating device, the gaseous refrigerant expansion device, the liquid refrigerant expansion device and the heat exchanger.
  • a temperature sensor disposed at one of the suction side of the first compressor unit and a pressure side of the first compressor unit
  • a control unit coupled to the temperature sensor and configured to control at least one of the desuperheating device, the gaseous refrigerant expansion device, the liquid refrigerant expansion device and the heat exchanger.
  • the refrigerant is C0 2 .
  • the properties of C0 2 in connection with the structure of the refrigerating system allow for a highly efficient overall system.
  • the refrigerating system is generally suitable for a wide variety of refrigerants.
  • the desuperheating device may be positioned in a machine room of the refrigerating system. This allows for a prevention of condensation of the refrigerant in the desuperheating device and a heating of the machine room. Also, the desuperheating device may be positioned in an outdoor location, which allows for a greater reduction of the refrigerant temperature in the desuperheating device in scenarios when the outdoor temperature is lower than, for example, an indoor machine room temperature.
  • the desuperheating device is positioned in a machine room of the refrigerating system and that the freezing branch comprises a second desuperheating device positioned in an outdoor location and arranged in parallel - in refrigerant circuit terms - with the desuperheating device in the machine room, with the refrigerant in operation being selectively directed to the desuperheating device in the machine room and the second desuperheating device.
  • the advantages of having the desuperheating device in a machine room and the advantages of having the desuperheating device in an outdoor location can be selectively chosen, depending on the momentary system and environment conditions. The selective choice may be carried out automatically, for example via a control unit having a thermostat.

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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)

Abstract

Un système de réfrigération (2) selon des modes de réalisation illustratifs de l'invention comprend un circuit réfrigérant comprenant les éléments suivants : une première unité de compresseur (4), un condenseur/refroidisseur de gaz (6), et un récipient de stockage (10); un branchement de réfrigération normale accouplé entre le récipient de stockage (10) et un côté d'aspiration de la première unité de compresseur (4), le branchement de réfrigération normale comprenant un premier dispositif d'expansion (22) et un premier évaporateur (24); et un branchement de congélation accouplé entre le récipient de stockage (10) et le côté d'aspiration de la première unité de compresseur (4), le branchement de congélation comprenant un second dispositif d'expansion (26), un second évaporateur (28), une seconde unité de compresseur (30) et un dispositif désurchauffeur (32). Le circuit réfrigérant comprend en outre des conduits réfrigérants permettant de raccorder lesdits éléments et permettant la circulation d'un réfrigérant à travers ceux-ci.
PCT/EP2009/064769 2009-11-06 2009-11-06 Système de réfrigération et procédé de fonctionnement d'un système de réfrigération Ceased WO2011054396A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP09755868.8A EP2496894B1 (fr) 2009-11-06 2009-11-06 Système de réfrigération et procédé de fonctionnement d'un système de réfrigération
PCT/EP2009/064769 WO2011054396A1 (fr) 2009-11-06 2009-11-06 Système de réfrigération et procédé de fonctionnement d'un système de réfrigération
DK09755868.8T DK2496894T3 (en) 2009-11-06 2009-11-06 COOLING SYSTEM AND PROCEDURE FOR COOLING SYSTEM OPERATION

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2009/064769 WO2011054396A1 (fr) 2009-11-06 2009-11-06 Système de réfrigération et procédé de fonctionnement d'un système de réfrigération

Publications (1)

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WO2011054396A1 true WO2011054396A1 (fr) 2011-05-12

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EP (1) EP2496894B1 (fr)
DK (1) DK2496894T3 (fr)
WO (1) WO2011054396A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3431901A1 (fr) * 2017-07-19 2019-01-23 Heatcraft Refrigeration Products LLC Outil de prévention contre les inondations d'un système de refroidissement

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3234752A (en) * 1963-05-20 1966-02-15 Hussmann Refrigerator Co Desuperheater for refrigeration system
EP0431797A2 (fr) * 1989-11-22 1991-06-12 James C. Labrecque Système de réfrigération
US5235820A (en) * 1991-11-19 1993-08-17 The University Of Maryland Refrigerator system for two-compartment cooling
WO2006015741A1 (fr) 2004-08-09 2006-02-16 Linde Kältetechnik Gmbh Circuit frigorifique et procede de fonctionnement d'un circuit frigorifique
EP1707901A2 (fr) * 2005-03-30 2006-10-04 Sanyo Electric Co., Ltd. Dispositif frigorifique et réfrigérateur
WO2008019689A2 (fr) * 2006-08-18 2008-02-21 Knudsen Køling A/S Système de réfrigération transcritique doté d'un surpresseur
EP1914491A2 (fr) 2006-10-17 2008-04-23 Bitzer Kühlmaschinenbau GmbH Installation de refroidissement

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1686330A2 (fr) * 2005-01-31 2006-08-02 Sanyo Electric Co., Ltd. Appareil réfrigérant, réfrigérateur, compresseur et séparateur gaz-liquide

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3234752A (en) * 1963-05-20 1966-02-15 Hussmann Refrigerator Co Desuperheater for refrigeration system
EP0431797A2 (fr) * 1989-11-22 1991-06-12 James C. Labrecque Système de réfrigération
US5235820A (en) * 1991-11-19 1993-08-17 The University Of Maryland Refrigerator system for two-compartment cooling
WO2006015741A1 (fr) 2004-08-09 2006-02-16 Linde Kältetechnik Gmbh Circuit frigorifique et procede de fonctionnement d'un circuit frigorifique
EP1707901A2 (fr) * 2005-03-30 2006-10-04 Sanyo Electric Co., Ltd. Dispositif frigorifique et réfrigérateur
WO2008019689A2 (fr) * 2006-08-18 2008-02-21 Knudsen Køling A/S Système de réfrigération transcritique doté d'un surpresseur
EP1914491A2 (fr) 2006-10-17 2008-04-23 Bitzer Kühlmaschinenbau GmbH Installation de refroidissement

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3431901A1 (fr) * 2017-07-19 2019-01-23 Heatcraft Refrigeration Products LLC Outil de prévention contre les inondations d'un système de refroidissement
CN109282543A (zh) * 2017-07-19 2019-01-29 西克制冷产品有限责任公司 冷却系统溢流防止工具
US10496108B2 (en) 2017-07-19 2019-12-03 Heatcraft Refrigeration Products Llc Cooling system flood prevention tool

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Publication number Publication date
DK2496894T3 (en) 2019-04-15
EP2496894B1 (fr) 2019-01-02
EP2496894A1 (fr) 2012-09-12

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