Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/32—Cooling devices
  • B60H1/3204—Cooling devices using compression
  • B60H1/3205—Control means therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/32—Cooling devices
  • B60H1/3204—Cooling devices using compression
  • B60H1/3205—Control means therefor
  • B60H1/3211—Control means therefor for increasing the efficiency of a vehicle refrigeration cycle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/32—Cooling devices
  • B60H1/3204—Cooling devices using compression
  • B60H1/3227—Cooling devices using compression characterised by the arrangement or the type of heat exchanger, e.g. condenser, 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
  • F25B41/00—Fluid-circulation arrangements
  • F25B41/30—Expansion means; Dispositions thereof
  • F25B41/39—Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/32—Cooling devices
  • B60H2001/3236—Cooling devices information from a variable is obtained
  • B60H2001/3239—Cooling devices information from a variable is obtained related to flow
  • B60H2001/3242—Cooling devices information from a variable is obtained related to flow of a refrigerant
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/32—Cooling devices
  • B60H2001/3236—Cooling devices information from a variable is obtained
  • B60H2001/3248—Cooling devices information from a variable is obtained related to pressure
  • B60H2001/3251—Cooling devices information from a variable is obtained related to pressure of the refrigerant at a condensing unit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/32—Cooling devices
  • B60H2001/3269—Cooling devices output of a control signal
  • B60H2001/3276—Cooling devices output of a control signal related to a condensing unit
  • B60H2001/3279—Cooling devices output of a control signal related to a condensing unit to control the refrigerant flow
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/32—Cooling devices
  • B60H2001/3269—Cooling devices output of a control signal
  • B60H2001/3285—Cooling devices output of a control signal related to an expansion unit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/32—Cooling devices
  • B60H2001/3286—Constructional features
  • B60H2001/3297—Expansion means other than expansion valve
• • 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
  • F25B2339/00—Details of evaporators; Details of condensers
  • F25B2339/04—Details of condensers
  • F25B2339/044—Condensers with an integrated receiver
  • F25B2339/0441—Condensers with an integrated receiver containing a drier or a filter
• • 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
  • F25B2339/00—Details of evaporators; Details of condensers
  • F25B2339/04—Details of condensers
  • F25B2339/044—Condensers with an integrated receiver
  • F25B2339/0445—Condensers with an integrated receiver with throttle portions
• • 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
  • F25B2500/01—Geometry problems, e.g. for reducing size

Definitions

• the invention relates to a coolant loop, in particular for an air conditioning installation for the passenger compartment of a vehicle.
• JP-A-95 81383 describes such a loop comprising a compressor capable of raising the pressure of the fluid in the gaseous state, a condenser capable of condensing the fluid compressed by the compressor and of sub-cooling it in the liquid state, a pre-expansion device capable of lowering the pressure of the fluid leaving the condenser, before it passes through a separating tank capable of separating the residual gas from the fluid in the liquid state coming from the condenser, a pressure reducing valve capable of lowering the pressure of the fluid leaving the tank and an evaporator capable of passing the fluid coming from the pressure reducer from the liquid state to the gaseous state before its return to the compressor.
• FIG. 1 is a diagram representing a thermodynamic cycle described by the refrigerant in an air conditioning loop, plotted in a system of enthalpy / pressure coordinates.
• a bell-shaped curve L envelops a zone of coexistence between liquid and gas, while the fluid is entirely in the liquid state to the left of the left flank of the curve and entirely in the gaseous state to the right of the right flank.
• the cycle has substantially the shape of a rectangular trapezoid with horizontal bases. From a point A located in the gas zone, the compressor brings the fluid in the gaseous state to a point B corresponding to a higher enthalpy and pressure than those of point A. In the condenser, the fluid travels a horizontal segment from point B to point E located in the liquid zone, which segment crosses the right and left flanks of the curve L at points C and D respectively.
• the BC, CD and DE segments correspond respectively- ment to a desuperheating of the gaseous fluid, to condensation and to a sub-cooling of the fluid in the liquid state.
• the fluid At the inlet of the evaporator, the fluid is at a point G located in the liquid / gas zone, corresponding to the same enthalpy value as point E and to the same pressure value as point A. In 1 evaporator, the fluid is brought back to the point A by crossing in H the right flank of the curve L.
• the fluid passes through the separator tank at point E of the thermodynamic cycle, and travels through the segment EG in the expansion valve.
• the point E being located in the liquid zone, the reservoir is then completely filled with liquid and the quantity of fluid which it contains cannot vary.
• this reduction is effected in particular at the expense of the condenser, whose sub-cooling capacity is thus reduced, which has the effect of raising the enthalpy level of the fluid at the outlet of the condenser and at the inlet of the evaporator and consequently to reduce the calorific power absorbed by the fluid in one evaporator.
• thermodynamic state of the fluid in the tank corresponds to the point D of the cycle, located on the saturation curve, which allows the reservoir to contain a variable quantity of fluid depending on the total mass of fluid in the circuit.
• this same result can be obtained in a loop as defined in the introduction, by interposing between the condenser and the tank a pre-expansion device capable of producing a pressure drop of between 1.5 and 14 bars so as to reduce the pressure of the fluid to its saturated vapor pressure.
• the pre-expansion device brings the fluid from the thermodynamic state corresponding to point E to that corresponding to point F, located again on the saturation curve, a state in which the fluid contained in the separating tank is therefore found.
• the regulator then brings the fluid from point F to point G.
• the pre-expansion device is capable of producing a pressure drop of between 4 and 10 bars.
• the pre-expansion device comprises a constriction defining a minimum passage section of between 0.2 and 7 mm 2 approximately in a pipe traversed by the entire flow of fluid leaving the condenser.
• the passage section substantially retains its minimum value over a length of between 0.1 and 5 mm.
• the minimum passage section does not exceed 50% of the passage section of the pipe upstream and / or downstream of the constriction.
• the passage section gradually decreases in an initial region of the constriction, substantially retains its minimum value in an intermediate region and gradually increases in a final region.
• the constriction is formed by an insert introduced into a substantially cylindrical pipe.
• the constriction is formed by a thickening of the wall of a substantially cylindrical pipe.
• the constricted passage is adjacent to the cylindrical wall.
• the constricted passage is substantially centered relative to the cylindrical wall.
• the throttle is formed by a washer crimped in the pipe.
• the pre-expansion device is housed in an outlet pipe mounted on a condenser manifold.
• FIG. 2 is a diagram showing the variation of the degree of sub-cooling produced by the condenser as a function of the mass of fluid in a loop according to the invention
• FIG. 3 is a diagram of a coolant loop according to the invention.
• - Figure 4 is a diagram showing the variation of the cooling capacity of a loop according to the invention as a function of the pressure drop produced by the pre-expansion device
• - Figure 5 is a schematic representation of a condenser having an outlet manifold and an outlet manifold which can either receive a pre-expansion device according to the invention
• FIG. 6 to 8 are schematic representations showing different ways of achieving a constriction in the outlet pipe.
• FIG. 9 is a schematic representation of a one-piece sub-assembly comprising a condenser, a pre-expansion device and a separator tank.
• the loop 1 shown diagrammatically in FIG. 3 comprises a compressor 2, a condenser 3, a pre-expansion device 4, a separator tank or "bottle” 5, a regulator 6 and an evaporator 7, traversed in this order by the refrigerant.
• the lower part of the reservoir 5 is filled with fluid in the liquid state, the residual gas entering the reservoir remains above the liquid level and only fluid in the liquid state is withdrawn below this level to be sent to the pressure reducer 6.
• the condenser 3 are schematically indicated a part of desuperheating 3-1 where the fluid in the gaseous state coming from the compressor is cooled to the liquid-gas equilibrium temperature, a part of condensation 3 -2 where the fluid is condensed at the equilibrium temperature, and a sub-cooling part 3-3 where the fluid in the liquid state is cooled below the equilibrium temperature.
• the evaporator 7 comprises a vaporization part 7-1 and a superheat part 7-2.
• FIG. 2 provides a curve representative of the variation of the difference ⁇ T between the liquid / gas equilibrium temperature in the condenser (condensing temperature) and the temperature of the fluid leaving the condenser, after sub-cooling, in function of the mass m of fluid contained in a loop according to the invention.
• This curve is formed by a first ascending part up to a value m lt of a second horizontal part from m ⁇ to m 2 and a third ascending part beyond m 2 .
• the plateau is obtained by varying the quantity of fluid contained in the reservoir 5, the values ⁇ ⁇ and m 2 corresponding respectively to the minimum and maximum levels of liquid therein.
• the degree of sub-cooling, and therefore the performance of the loop, remains substantially constant until the leaks reduce the mass of fluid to m 1 .
• the initial mass of fluid is preferably chosen in the vicinity of m 2 so that the duration of stable operation is as long as possible.
• the length of the bearing is itself a function of the liquid / gas separation capacity and the volume of the reservoir.
• the pre-expansion device is represented by way of example in the form of a diaphragm 4-1 arranged across the path of the fluid and having an orifice 4-2.
• the condenser 3, the pre-expansion device 4 and the tank 5 can be arranged at a distance from each other and connected to each other by connecting pipes.
• FIG. 5 schematically shows a condenser comprising an inlet manifold 10 provided with an inlet manifold 11, an outlet manifold 12 provided with an outlet manifold 13 and a bundle of tubes 14 through which the fluid circulates between different chambers formed in the manifolds.
• the pre-expansion device of the invention can advantageously be housed either in the manifold 12, or in the tube 13, in the zone A where these are connected.
• FIG. 6 shows a pre-expansion device formed by an insert 20 introduced into the outlet tube 13 and applied against the cylindrical wall of the latter, over a fraction of its perimeter, leaving a constricted passage 21 adjacent to the remaining part from the perimeter of the wall.
• the passage 21 has a minimum passage section S2 which does not exceed 50% of the passage section Si of the pipe 13 upstream and downstream of the insert 20, the section S2 advantageously being between 0.2 and 7 mm 2 approx.
• the insert 20 has a trapezoidal profile by which the passage section decreases progressively in an initial region of the constriction, retains its minimum value in an intermediate region and gradually increases in a final region.
• the insert 20 is replaced by a washer 22 arranged across the tube 13 and having a central hole 23 defining a constricted passage, the passage section of which is constant here and fulfills the conditions indicated in connection of the minimum passage section of the constriction 21.
• the length of the constriction 23, that is to say the thickness of the washer 22 is between 0.1 and 5 mm.
• the washer 22 can be fixed by crimping, by deforming the thin wall of the tube 13 on either side of its thickness.
• FIG. 8 shows an outlet tube 13 with a thick wall, for example molded, mechanically fixed on the outlet box 12 of the condenser.
• Tubing 13 has a rib internal circumferential 24 leaving a central passage of reduced section.
• the rib 24 has a trapezoidal profile by which the cross-section of the throttle 25 varies in a similar manner to that of the throttle 21.
• Figure 9 shows a condenser 3 similar to that of Figure 5 and a separator tank 5 attached to the outlet manifold 12, the box 12 and the tank 5 being elongated vertically.
• the outlet pipe 13 is housed in the tank 5 and is curved so as to extend upwards and open out at the upper part of the tank, into a space 30 where the residual gas leaving the condenser collects.
• the space 30 is separated from the lower space 31 of the reservoir by a filtration zone 32 which is traversed by the tubing 13.
• the fluid in the liquid state leaves the reservoir through a lower tubing 33 communicating with the space 31.
• the pre-expansion device 4 is interposed on the tubing 13 and therefore housed in the reservoir 5.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Air-Conditioning For Vehicles (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9527746

Family Applications (1)

Country Status (5)

Families Citing this family (6)

Family Cites Families (7)

• 1998
  • 1998-06-23 FR FR9807929A patent/FR2779994B1/fr not_active Expired - Fee Related
• 1999
  • 1999-06-23 JP JP2000555767A patent/JP2003513836A/ja active Pending
  • 1999-06-23 WO PCT/FR1999/001514 patent/WO1999067101A2/fr not_active Application Discontinuation
  • 1999-06-23 EP EP99957155A patent/EP1007380A1/fr not_active Withdrawn
  • 1999-06-23 US US09/486,132 patent/US6425262B1/en not_active Expired - Fee Related

Non-Patent Citations (1)

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