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
  • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
  • F25B43/02—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
• • 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
  • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
  • F25B43/006—Accumulators
• • 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
  • F25B41/22—Disposition of valves, e.g. of on-off valves or flow control valves between evaporator and 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
  • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
• • 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—Component parts or details not otherwise provided for in this subclass
  • F25B2400/04—Refrigeration circuit bypassing means
  • F25B2400/0409—Refrigeration circuit bypassing means for evaporators
• • 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—Component parts or details not otherwise provided for in this subclass
  • 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
  • F25B2600/00—Control issues
  • F25B2600/25—Control of valves
  • F25B2600/2501—Bypass valves

Definitions

• This invention relates generally to air conditioning and refrigeration systems and, more particularly, to parallel flow evaporators thereof.
• a definition of a so-called parallel flow heat exchanger is widely used in the air conditioning and refrigeration industry now and designates a heat exchanger with a plurality of parallel passages, among which refrigerant is distributed and flown in the orientation generally substantially perpendicular to the refrigerant flow direction in the inlet and outlet manifolds. This definition is well adapted within the technical community and will be used throughout the text.
• Refrigerant maldistribution in refrigerant system evaporators is a well-known phenomenon. It causes significant evaporator and overall system performance degradation over a wide range of operating conditions.
• Maldistribution of refrigerant may occur due to differences in flow impedances within evaporator channels, non-uniform airflow distribution over external heat transfer surfaces, improper heat exchanger orientation or poor manifold and distribution system design. Maldistribution is particularly pronounced in parallel flow evaporators due to their specific design with respect to refrigerant routing to each refrigerant circuit. Attempts to eliminate or reduce the effects of this phenomenon on the performance of parallel flow evaporators have been made with little or no success. The primary reasons for such failures have generally been related to complexity and inefficiency of the proposed technique or prohibitively high cost of the solution.
• the inlet and outlet manifolds or headers usually have a conventional cylindrical shape.
• the vapor phase is usually separated from the liquid phase. Since both phases flow independently, refrigerant maldistribution tends to occur.
• the liquid phase (droplets of liquid) is carried by the momentum of the flow further away from the manifold entrance to the remote portion of the header.
• the channels closest to the manifold entrance receive predominantly the vapor phase and the channels remote from the manifold entrance receive mostly the liquid phase.
• the velocity of the two-phase flow entering the manifold is low, there is not enough momentum to carry the liquid phase along the header.
• the liquid phase enters the channels closest to the inlet and the vapor phase proceeds to the most remote ones.
• the liquid and vapor phases in the inlet manifold can be separated by the gravity forces, causing similar maldistribution consequences.
• minichannel and microchannel heat exchangers differ only by a channel size (or so-called hydraulic diameter) and can equally benefit from the teachings of the invention.
• channel size or so-called hydraulic diameter
• a liquid- vapor separator is provided between the expansion device and the inlet header such that the separator causes the refrigerant vapor to pass directly to the compressor and only liquid refrigerant to pass to the inlet manifold. In this way, a more uniform distribution of liquid refrigerant to the individual parallel channels is obtained.
• the liquid-vapor separator comprises a float valve with a float member oriented to move vertically to permit the flow of refrigerant vapor therearound but if liquid refrigerant flows into the valve, the float member will tend to seat and prevent the flow of liquid refrigerant therethrough.
• a second float valve is interconnected between a downstream end of the inlet manifold and the compressor such that the residual vapor from the liquid refrigerant will pass directly to the compressor.
• FIG. 1 is a schematic illustration of one embodiment of the invention.
• Fig. 2 is a modified version thereof.
• Fig. 3 is an alternate embodiment of the present invention.
• Fig. 4 is a modified version thereof.
• FIG. 1 the invention is shown generally at 10 as applied to a minichannel heat exchanger 11 having an inlet manifold 12, an outlet manifold 13, and a plurality of parallel microchannels 14 interconnecting the inlet manifold 12 to the outlet manifold 13.
• An inlet chamber 16 is fluidly connected to the upstream end 17 of the inlet manifold 12 by way of conduit 18.
• an inlet line 19 provides fluid communication from an expansion device such that a mixture of liquid and vapor refrigerant flows into the upper portion of the inlet chamber 16.
• the heavier liquid refrigerant tends to fall to the bottom of the inlet chamber 16 and flow through the conduit 18 to the inlet manifold 12 such that each of the parallel minichannels 14 have single phase liquid refrigerant presented at their inlet ends.
• bypass duct 21 for conducting the flow of refrigerant vapor to the compressor as indicated by the arrows.
• a float valve 22 Disposed within the bypass duct 21 is a float valve 22 having an inlet port 23, an outlet port 24, and a float member 26.
• a conduit 28 is connected to provide fluid communication to the compressor by way of a second float valve 29.
• This float valve separator operates in the same manner as the float valve 22 as described hereinabove to remove any residual vapor that may be in the downstream end 27 of the inlet manifold 12. That is, all liquid refrigerant in the manifold 12 should flow upwardly through the microchannels 14, and any residual vapor would pass upwardly through the conduit 28, the float valve 29 and to the compressor.
• piping arrangement 31 will contain less liquid refrigerant, it operates in substantially the same way as the inlet chamber 16 as described hereinabove.
• the Fig. 1 and Fig. 2 embodiments as described hereinabove relate to arrangements wherein the heat exchanger 11 is orientated such that the manifolds 12 and 13 are horizontal and the minichannels 14 are vertical.
• the Fig. 3 embodiment illustrates the invention as used in a configuration wherein the headers are orientated vertically and the minichannels are orientated horizontally.
• the minichannel heat exchanger 32 has a manifold 33, a manifold 34 and parallel minichannels 36.
• the manifold 33 is divided into upper and lower sections 37 and 38, with the microchannels 36 in the lower sections 38 acting to conduct the flow of refrigerant to the manifold 34 and the minichannels in the upper section 37 acting to conduct the flow of refrigerant from the manifold 34 back to the upper section 37 of the manifold 33.
• a float valve 39 is provided in a line 41 connecting the upper section 37 of the inlet manifold 33 to the compressor. This float valve operates in the same manner as the float valve 29 of the Fig. 2 embodiment to remove any residual vapor from the liquid.
• a conduit 42 for fluid communication between the downstream end of manifold 34 and the compressor suction.
• a float valve 43 is provided and operates in the same manner as the float valve described hereinabove. Its purpose is to separate any vapor that appears after the first pass of the heat exchanger so that only liquid refrigerant is fed to the second pass of the heat exchanger.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Power Engineering (AREA)
• Air-Conditioning For Vehicles (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
• Separation Using Semi-Permeable Membranes (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

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• 2005
  • 2005-12-28 MX MX2007009257A patent/MX2007009257A/es not_active Application Discontinuation
  • 2005-12-28 KR KR1020077016458A patent/KR20070091343A/ko not_active Ceased
  • 2005-12-28 WO PCT/US2005/047359 patent/WO2006083445A2/en not_active Ceased
  • 2005-12-28 AU AU2005326650A patent/AU2005326650B2/en not_active Ceased
  • 2005-12-28 CN CNA2005800476835A patent/CN101111731A/zh active Pending
  • 2005-12-28 CA CA002596331A patent/CA2596331A1/en not_active Abandoned
  • 2005-12-28 EP EP05855852A patent/EP1844271A4/de not_active Withdrawn
  • 2005-12-28 US US11/794,774 patent/US20080104975A1/en not_active Abandoned
  • 2005-12-28 BR BRPI0519906-9A patent/BRPI0519906A2/pt not_active IP Right Cessation
  • 2005-12-28 JP JP2007554088A patent/JP2008528939A/ja active Pending

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