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
  • F25B41/00—Fluid-circulation arrangements
  • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
  • F25B41/24—Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
• • 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
  • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
• • 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
  • F25B49/00—Arrangement or mounting of control or safety devices
  • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
  • F25B49/022—Compressor control arrangements
• • 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
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D11/00—Self-contained movable devices, e.g. domestic refrigerators
• • 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
  • F25B2400/04—Refrigeration circuit bypassing means
  • F25B2400/0403—Refrigeration circuit bypassing means for the condenser
• • 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
  • F25B2400/04—Refrigeration circuit bypassing means
  • F25B2400/0409—Refrigeration circuit bypassing means for the evaporator
• • 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
  • F25B2400/04—Refrigeration circuit bypassing means
  • F25B2400/0411—Refrigeration circuit bypassing means for the expansion valve or capillary tube
• • 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
  • F25B2500/00—Problems to be solved
  • F25B2500/26—Problems to be solved characterised by the startup of the refrigeration cycle
• • 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
  • F25B2600/00—Control issues
  • F25B2600/02—Compressor control
  • F25B2600/025—Compressor control by controlling speed
  • F25B2600/0251—Compressor control by controlling speed with on-off operation
• • 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
  • F25B2600/00—Control issues
  • F25B2600/02—Compressor control
  • F25B2600/026—Compressor control by controlling unloaders
• • 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
  • F25B2600/00—Control issues
  • F25B2600/25—Control of valves
  • F25B2600/2519—On-off valves
• • 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
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D2700/00—Means for sensing or measuring; Sensors therefor
  • F25D2700/12—Sensors measuring the inside temperature
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Definitions

• the present invention relates to a method of operating a refrigeration system.
• the invention further relates to a refrigerator comprising a compartment cooled by a refrigeration system.
• Such cooled domestic and commercial foodstuff storage compartments may form part of above freezing point refrigerators or below freezing point refrigerators, the latter are sometimes referred to as freezers.
• freezers both types will be referred to as refrigerators.
• a refrigerant circulates in the refrigeration system while the compressor runs, compressing the gaseous refrigerant coming from the evaporator.
• the gaseous refrigerant As the refrigerant circulates, the gaseous refrigerant is cooled and condenses to a liquid state in the condenser, which is arranged outside of the compartment. Thereafter, the liquid refrigerant is subjected to a pressure drop in the expansion arrangement and evaporates from the liquid state in the evaporator.
• the evaporator is arranged in thermal
• the compartment is cooled by the refrigerant.
• a refrigeration system is designed to provide a specific cooling capacity.
• the refrigeration system provides the specific cooling capacity when it reaches a steady "on" state after the compressor has been running for a while.
• the specific cooling capacity is higher than the long term cooling requirement of the compartment.
• the compressor is running during a first duration, an on-period, and not running during a second duration, an off-period.
• One compressor cycle during the operation of the refrigeration system is constituted by one on-period and one off-period. Accordingly, during operation the refrigeration system runs through many compressor cycles. The operation of the compressor and its cycle length is dependent of the temperature inside the
• compressor control parameters are a maximum allowed temperature in the compartment, at which the compressor is started, and a minimum temperature, at which the compressor is stopped.
• EP 727628 discloses a control device for controlling temperature in a refrigerator and a method of controlling the temperature in refrigerators.
• the purpose is to provide a control device and a method of controlling the temperature in refrigerators by means of which the cooling source may be controlled to minimize the energy consumption of the refrigerator.
• This is achieved by means of a control algorithm in which a requirement variable is formed.
• the requirement variable formed indicates a ratio of the switch-on duration (the above-mentioned on-period) of the cooling source to the switch-off duration (the above-mentioned off-period) of the cooling source.
• an actual temperature averaged over time is used as the actual temperature for forming a differential between a set-point temperature and an actual temperature.
• a refrigeration system is subjected to cyclic losses.
• the losses are due to: 1. Liquid refrigerant, instead of gaseous refrigerant, being extracted from the evaporator at the beginning of an on-period. 2. Gaseous refrigerant being pumped through the expansion arrangement in the form of a capillary tube before a liquid seal is formed at the beginning of the on-period. 3. Improperly charged condenser and evaporator before equilibrium has been established during the on-period. 4.
• a high start up current may be required depending on the type of compressor operation, which also may contribute to losses in systems comprising a refrigeration system.
• EP 727628 does not take account of cyclic losses in a relevant refrigeration system.
• WO 2006/044787 is concerned with a pressure equalization system which solves a problem specific to HVAC (Heating Ventilation Air Conditioning) systems.
• HVAC Heating Ventilation Air Conditioning
• pressure tends to equalize between low pressure and high pressure sides when the compressor stops operating, and that in a refrigeration cycle energy is required at start up to create a high pressure in the compressor.
• pressure does not equalize between the condenser and the evaporator (high pressure side and low pressure side of the refrigeration system) during the off-periods of the compressor. This creates a need for additional components, which enable a high pressure difference start-up of the compressor.
• the pressure equalization system of WO 2006/044787 comprises a bleed port interconnecting the high pressure side of the compressor with the low pressure side of the compressor (outlet of compressor with inlet of compressor). Via the bleed port the pressure level in the compressor may be equalized to the low pressure level. Thus, the compressor may be started under low pressure difference conditions. Accordingly, the electrical system driving the compressor does not require any costly start capacitor or start relay.
• an object of the present invention is to further decrease energy
• the object is achieved by a method of operating a refrigeration system, wherein the refrigeration system comprises:
• an evaporator adapted to be arranged in thermal communication with a compartment to be cooled, - a compressor,
• the method comprises:
• the requirement variable being a ratio between a switch-on duration of the compressor and a switch-off duration of the compressor
• the refrigeration system further comprises a first shut-off valve arranged in a conduit extending between the condenser and the evaporator.
• the method further comprises:
• a first shut-off valve is closed when the compressor is switched off and not opened again until the compressor is switched on again to maintain a pressure difference between the condenser and the evaporator of the refrigeration system when the compressor is not running, cyclic losses in the refrigeration system as laid out above under points 1 - 4 are avoided, at least to a large extent.
• the refrigeration system and compartment may form part of a refrigerator, such as a domestic or commercial refrigerator for foodstuffs.
• the averaged temperature may for instance be calculated over a fixed period of time or over a number of compressor cycles.
• ratio between a switch-on duration of the compressor and a switch- off duration of the compressor encompasses both alternative calculations of the ratio, i.e. switch-on duration in relation to switch-off duration, as well as switch-off duration in relation to switch-on duration of the compressor.
• the requirement variable in the form of a ratio between a switch-on duration and a switch-off duration of the compressor may be applied to one compressor cycle length to establish the first duration and the second duration.
• the compressor cycle length may be fixed or may be set iteratively, e.g. to maintain a number of compressor cycles per time unit within a specified interval, such as e.g. 1 - 8 cycles/hour.
• the conduit in which the first shut-off valve is arranged is the conduit in which also the expansion arrangement is arranged.
• the refrigeration system may comprise the compartment and the compartment may be adapted for domestic foodstuff storing. In this manner the refrigeration system and the compartment may form part of a domestic refrigerator.
• the compressor may be a single speed compressor controlled by a control system to run at a constant speed during the first duration.
• a comparatively simple compressor may be operated in an economic manner.
• the compressor, and more specifically the electric motor driving the compressor may be provided with a start capacitor and/or a start relay and/or other means to start under high pressure difference conditions prevailing between an inlet side and an outlet side of the compressor due to the first shut-off valve being closed during the second duration.
• the refrigeration system further may comprise a valve arrangement in a conduit between the compressor and the condenser, and a by-pass conduit extending between an outlet side of the compressor and an inlet side of the compressor.
• the method further may comprise:
• a single speed compressor may be started at low pressure difference conditions and a start capacitor or other means may be omitted since the pressure difference between the inlet side and the outlet side of the compressor is equalized via the by-pass conduit.
• valve arrangement may comprise a check valve and the refrigeration system further may comprise a second shut-off valve arranged in the by- pass conduit.
• the method further may comprise:
• the valve arrangement may comprise a 3-way valve, the 3- way valve being connected to the by-pass conduit.
• the said equalizing the pressure difference may include:
• the method further may comprise:
• the expansion arrangement may comprise a capillary tube.
• the first shut-off valve may form part of the expansion arrangement.
• the first duration and the second duration may collectively have a length of between 1 - 100 minutes. That is, the compressor cycle may have said length. According to further embodiments, the first duration and the second duration may collectively have a length of between 3 - 30 minutes.
• short total first and second durations i.e. a short compressor cycle length
• a short compressor cycle length allows for a more even air temperature inside a compartment cooled by the evaporator. Furthermore, a higher humidity of air inside the compartment may be achieved.
• the compressor may be adapted to provide a cooling capacity of between 10 - 500 W according to ASHRAE LBP or HMBP standard.
• the compressor may be adapted to provide a cooling capacity of between 20 - 300 W according to ASHRAE LBP or HMBP standard. Such a compressor may provide sufficient cooling capacity for most domestic refrigerator applications.
• a refrigerator comprising a compartment cooled by a refrigeration system controlled by a control system, wherein the refrigeration system comprises:
• control system is adapted:
• the requirement variable being a ratio between a switch-on duration of the compressor and a switch-off duration of the compressor
• the refrigeration system comprises a first shut-off valve arranged in a conduit extending between the condenser and the evaporator, and the control system is further adapted:
• Embodiments mentioned above in relation to the method and the refrigeration system of the method may be embodied in a refrigerator.
• the compressor may be a single speed compressor controlled by the control system to run at a constant speed during the first duration.
• the refrigeration system further may comprise a valve arrangement in a conduit between the compressor and the condenser, and a by-pass conduit extending between an outlet side of the compressor and an inlet side of the compressor.
• valve arrangement may comprise a check valve and the refrigeration system further may comprise a second shut-off valve arranged in the bypass conduit, and wherein the control system may be adapted:
• valve arrangement may comprise a 3-way valve, the 3- way valve being connected to the by-pass conduit.
• control system may be adapted:
• the compressor alternatively may be a variable speed compressor controlled by the control system to run at variable speed during the first duration. In this manner a compressor may be provided which may be started at high pressure difference conditions.
• the refrigeration system may comprise a filter arranged in a conduit between the condenser and the expansion arrangement.
• the first shut-off valve may be arranged in a conduit between the filter and the expansion arrangement. In this manner it may be ensured that when the first shut-off valve is opened in connection with switching on the compressor, liquid refrigerant will enter the expansion arrangement.
• Fig. 1 illustrates schematically a refrigerator according to embodiments and a
• Fig. 2 illustrates a method of operating a refrigeration system according to embodiments
• Figs. 3 and 4 illustrate portions of refrigeration systems according to embodiments
• Fig. 5 illustrates a refrigeration system according to embodiments.
• Fig. 1 illustrates schematically a refrigerator 2 according to embodiments and a refrigeration system 4 according to embodiments.
• the refrigerator 2 comprises the refrigeration system 4 and a compartment 6, e.g. for storing foodstuff.
• the refrigeration system 4 comprises an evaporator 8, a compressor 10, a condenser 12, a filter 14 and an expansion arrangement 15 comprising a capillary tube 16.
• Conduits are arranged to interconnect the mentioned components of the refrigeration system 4. Accordingly, the filter 14 is arranged in a conduit ext ending between the condenser 12 and the expansion arrangement 15.
• a refrigerant circulates in the refrigeration system 4. Circulation of the refrigerant is driven by a pressure difference between the condenser 12 and the evaporator 8.
• the pressure difference is created by the compressor 10, compressing gaseous refrigerant which has evaporated from liquid refrigerant in the evaporator 8.
• the gaseous refrigerant is cooled and condenses to a liquid state in the condenser 12.
• the liquid refrigerant passes through the filter 14, which may collect debris and water in the refrigerant.
• the expansion arrangement 15 the liquid refrigerant is subjected to a pressure drop to thereafter evaporate from the liquid state in the evaporator 8.
• the evaporator 8 is arranged in thermal communication with the compartment 6 and thus, cools the compartment 6 when refrigerant evaporates in the evaporator 8.
• the refrigeration system 4 further comprises a first shut-off valve 20 arranged in a first conduit 22 extending between the condenser 12 and the evaporator 8, i.e. a conduit 22 also comprising the expansion arrangement 15.
• the first shut-off valve 20 is arranged in the first conduit 22 between the filter 14 and the expansion arrangement 15.
• the first conduit 22 may be closed by means of the first shut-off valve 20.
• the first shut-off valve 20 has two discrete positions, one fully closed position and one fully open position.
• An electric motor 24 drives the compressor 10.
• a control system 26 is arranged to control the operation of the refrigeration system 4.
• the control system 26 may comprise a microprocessor programmed to control the operation of the refrigeration system 4. Alternatively, the control system 26 may comprise discrete electric components connected to control the refrigeration system 4.
• the control system 26 further comprises a temperature sensor 28 arranged in the compartment 6 and is connected to the electric motor 24 for controlling the compressor 10, and to the first shut-off valve 20. Control parameters of the refrigeration system 4 may be preset in the control system
• Fig. 2 illustrates a method of operating a refrigeration system according to embodiments.
• the refrigeration system may be a refrigeration system 4 as described in connection with Fig. 1.
• the method comprises:
• the said establishing 100 the momentary cooling requirement may comprise simply establishing whether the refrigeration system 4 is to be switched on or off, i.e. whether the compressor 10 should be running or not.
• the requirement variable may be a ratio between a switch-on duration of the compressor 10 and a switch-off duration of the compressor 10.
• - Fixing 104 a first duration during which the compressor 10 is switched on and a second duration during which the compressor 10 is switched off on the basis of the requirement variable. For example, if a compressor cycle length is 20 minutes and the requirement variable is 40% switch-on duration and 60 % switch-off duration, the first duration is 8 minutes and the second duration is 12 minutes.
• the control system 26 is adapted to switch on and off the compressor 10 by means of switching on and off the electric motor 24.
• a refrigeration system 4 operated according to this method is advantageous in that it firstly, thanks to the requirement variable and the average temperature over time is used allows the compressor 10 to be run for optimal durations from a cooling requirement and energy consumption point of view. Secondly, thanks to the closing and opening of the first shut-off valve 20, cyclic losses in the refrigeration system 4 may be avoided, at least to a large extent. Thus, the method allows a refrigeration system 4 to be operated with low energy consumption by optimizing running characteristics and by eliminating cyclic losses.
• Method steps 100 - 104 are suitably performed at regular intervals by the control system 16 of the refrigeration system 4.
• Method steps 106 - 1 12 may be performed at the same regular intervals or at different intervals.
• the requirement variable being a ratio between a switch-on duration of the compressor 10 and a switch-off duration of the compressor 10,
• the compressor 10 may be a single speed compress or controlled by the control system 26 to run at a constant speed during the first duration. That is, the electric motor 24 has only one operational speed and the control system 26 is adapted to switch on and off the electric motor 24.
• the control system 26 may include a start capacitor and/or a start relay in order to be able to start the compressor 10 with the high pressure maintained in the condenser 12, and at the outlet side of the compressor, due to the first shut-off valve 20 being closed during the second duration when the compressor 10 is switched off.
• the compressor 10 may be a variable speed compressor controlled by the control system 26 to run at variable speed during the first duration. That is, the control system may either run the electric motor 24 at, at least, two different speeds during one first duration or alternatively, at a constant speed during one first duration and at a different constant speed during a following first duration.
• the requirement variable of the method may be specified to be maintained within a specified interval. If the requirement variable is outside the specified interval, the constant speed is increased or decreased, depending on whether the requirement variable is above or below the specified interval, in a following first duration.
• a variable speed compressor and its electric motor are adapted to be started against a high pressure difference between the condenser 12, i.e. the outlet side of the compressor 10 and the evaporator 8, ie. inlet side of the compressor 10.
• the compressor 10, single speed or variable speed may be adapted to provide a cooling capacity of between 10 - 500 W according to ASHRAE LBP or HMBP standard (at 55 degrees Celsius condensing temperature and - 23,3 degrees Celsius evaporating temperature). More specifically, in some applications the compressor 10 may be adapted to provide a cooling capacity of between 20 - 300 W according to ASHRAE LBP or HMBP standard.
• the first duration and the second duration may collectively have a length of between 1 - 100 minutes, i.e. the compressor cycle may have a length of 1 - 100 minutes. More specifically, the first duration and the second duration may collectively have a length of between 3 - 30 minutes.
• Fig. 3 illustrates a portion of a refrigeration system 4 according to embodiments.
• a compressor 10 such as a single speed compressor
• the refrigeration system 4 comprises a valve arrangement 32 in a conduit 34 between the compressor 10 and the condenser 12.
• a by-pass conduit 36 extends between an outlet side of the compressor 10 and an inlet side of the
• the valve arrangement 32 comprises a check valve 38.
• a second shut- off valve 40 is arranged in the by-pass conduit 36. When the second shut-off valve 40 is open, any pressure difference between the inlet side and the outlet side of the compressor 10 is equalized to substantially the pressure prevailing at the inlet side of the compressor 10.
• the check valve 38 ensures that a high pressure in the condenser 10 cannot be equalized in an upstream direction from the condenser 10.
• the second shut-off valve 40 is connected to a control system 26 of the refrigeration system 4.
• the control system 26 is adapted:
• the method illustrated in Fig. 2 may further comprise:
• Equalizing 1 14 a pressure difference between the outlet side and the inlet side of the compressor 10 during the second duration.
• Fig. 4 illustrates a portion of a refrigeration system 4 according to embodiments. Also these embodiments provide a solution which allows a compressor 10 to be started under low pressure difference conditions despite a high pressure prevailing in a condenser 12.
• the refrigeration system 4 comprises a valve arrangement 32 in a conduit 34 between the compressor 10 and the condenser 12.
• a by-pass conduit 36 extends between an outlet side of the compressor 10 and an inlet side of the compressor 10. Via the by-pass conduit 36, any pressure difference between the inlet side and the outlet side of the compressor 10 may be equalized to substantially the pressure prevailing at the inlet side of the compressor 10.
• the valve arrangement 32 comprises a 3-way valve 42. The 3- way valve is connected to the by-pass conduit 36.
• the 3-way valve is connected to a control system 26 of the refrigeration system 4.
• the control system 26 is adapted:
• Fig. 2 may comprise:
• Equalizing 1 14 a pressure difference between the outlet side and the inlet side of the compressor 10 during the second duration, the said equalizing 1 14 the pressure difference including:
• the method may further comprise:
• a constant speed compressor does not require any start capacitor or other means to permit starting despite a high pressure prevailing in the condenser 12.
• the embodiments of Figs. 3 and 4 may be used in refrigeration systems 4 according to Figs. 1 and 5.
• Fig. 5 illustrates a refrigeration system 4 according to embodiments.
• the refrigeration system 4 comprises an evaporator 8, a compressor 10, a condenser 12, and an expansion arrangement 15.
• the expansion arrangement 15 comprises a first shut-off valve 20 or put differently, the first shut-off valve 20 forms part of the expansion arrangement 15. Accordingly, when the compressor 10 is running and liquid refrigerant evaporates in the evaporator 8, the first shut-off valve 20 acts as an expansion valve for liquid refrigerant. When the compressor 10 is not running the first shut-off valve 20 is closed to prevent cyclic losses in the refrigeration system 4.
• a control system 26 of the refrigeration system 4 controls inter alia the first shut-off valve 20.
• a refrigeration system 4 according to embodiments may be operated according to a method according to embodiments for a period of time. Whereas during other periods of time the refrigeration system 4 may be operated according to a different method, e.g. if a difference between a set-point temperature and an actual temperature exceeds a threshold value.
• Example embodiments and components described above may be combined as understood by a person skilled in the art. Accordingly, when herein reference is made to some components relating to the compressor, such as a start capacitor, the electric motor of the compressor is encompassed in the expression "compressor”.
• the check valve 38 of the Fig. 3 embodiments may be arranged in the conduit extending between the evaporator 8 and the compressor 10 upstream of the by-pass conduit 36.
• the 3-way valve 42 in the Fig. 4 embodiments may be arranged in the conduit extending between the evaporator 8 and the compressor 10 and be connected to the compressor inlet side of the by-pass conduit 36.
• the common abbreviation "e.g.” which derives from the Latin phrase “exempli gratia,” may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. If used herein, the common abbreviation “i.e.”, which derives from the Latin phrase “id est,” may be used to specify a particular item from a more general recitation.
• first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used top distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed herein could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

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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)
• Combustion & Propulsion (AREA)
• Devices That Are Associated With Refrigeration Equipment (AREA)

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• 2011
  • 2011-10-03 AU AU2011378695A patent/AU2011378695B2/en not_active Ceased
  • 2011-10-03 RU RU2014113069/06A patent/RU2562834C1/ru not_active IP Right Cessation
  • 2011-10-03 WO PCT/EP2011/067213 patent/WO2013050055A1/en active Application Filing
  • 2011-10-03 CN CN201180073953.5A patent/CN103874896A/zh active Pending
  • 2011-10-03 KR KR1020147008862A patent/KR20140071411A/ko not_active Application Discontinuation
  • 2011-10-03 US US14/347,053 patent/US20140318161A1/en not_active Abandoned
  • 2011-10-03 BR BR112014007624A patent/BR112014007624A2/pt not_active Application Discontinuation
  • 2011-10-03 EP EP11763953.4A patent/EP2764304A1/en not_active Withdrawn
• 2017
  • 2017-02-16 US US15/434,931 patent/US20170159983A1/en not_active Abandoned

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