US 6,644,052 B1Granted

Vapor compression system and method

AssigneeXDx, Inc.

InventorDavid A. Wightman

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Abstract

A vapor compression refrigeration and freezer system includes a compressor, a condenser, an expansion devise and an evaporator which includes an evaporator coil having an inlet and an outlet which coil is in heat exchange relation with an air medium along substantially the entire coil length. The inlet to the evaporator coil is in flow communication with an outlet of the expansion devise via an evaporator feedline. The expansion device can include a multifunctional valve that cooperates with the evaporator feedline to supply the evaporator coil inlet with a mixture of refrigerant vapor and liquid at a linear velocity and with relative amounts of vapor and liquid which are sufficient to provide efficient heat transfer along substantially the entire length of the coil, substantially reducing the build-up of frost on the evaporator coil and enabling the system to be operated without requiring a defrosting cycle over a substantially increased number of operating cycles compared to conventional refrigeration and freezer systems operating at the same cooling load and evaporating temperature conditions.

Claims30

Dependent claims

A method of operating a vapor compression refrigeration system wherein an evaporator removes heat from a medium which is circulated through said evaporator in heat exchange relation with an evaporator coil in said evaporator, said coil including an inlet which is in flow communication with an expansion device and an outlet which is in flow communication with a compressor, the method comprising:

compressing a refrigerant fluid in said compressor;
condensing said refrigerant fluid in a condenser to form a condensed refrigerant fluid;
expanding said condensed refrigerant fluid in said expansion device to form an expanded refrigerant fluid, wherein said expanded refrigerant fluid is in a liquid form or substantially in said liquid form with a small vapor fraction;
supplying said expanded refrigerant to an evaporator feed line connecting said expansion device to said evaporator coil inlet;
converting a significant amount of said liquid form to a liquid and vapor mixture within said evaporator feed line, wherein the diameter and length of said evaporator feed line facilitates said conversion;
supplying said mixture of refrigerant vapor and liquid to said evaporator coil inlet, and
converting substantially all of said liquid to vapor as said mixture passes through said evaporator coil;
wherein said evaporating coil is sized to provide refrigerant comprising liquid and vapor at said outlet of said evaporator coil during the portion of each refrigeration cycle when said expansion device is supplying said mixture of said refrigerant vapor and liquid to said evaporating coil inlet.

5 more elements

A vapor compression refrigeration system comprising:

a compressor for increasing the pressure and temperature of a refrigerant vapor, said compressor having an inlet and an outlet;
a condenser having an inlet in flow communication with the outlet of said compressor for liquefying pressurized refrigerant vapor received from said compressor;
an expansion device having a first inlet which, during a cooling mode of operation of said refrigeration system, is in flow communication with an outlet of said condenser for receiving liquid refrigerant from said condenser and expanding the same to form an expanded refrigerant fluid, wherein said expanded refrigerant fluid is in a liquid form or substantially in said liquid form with a small vapor fraction;
an evaporator including an evaporating coil having an inlet and an outlet, said evaporating coil being in heat exchange relation with an air medium along substantially the entire length of said coil;
an evaporator feed line providing flow communication of said expansion device with said evaporating coil inlet;
a suction line providing flow communication of said evaporating coil outlet with said compressor inlet;
said expansion device and said evaporator feed line, during a cooling mode of operation of said vapor compression refrigeration system, being sized to convert a significant amount of said liquid form to a liquid and vapor mixture within said evaporator feed line and to provide said evaporating coil inlet with a refrigerant liquid and vapor mixture that includes a substantial vapor portion,
said evaporating coil being sized to provide refrigerant comprising liquid and vapor at said outlet of said evaporator coil during the portion of each refrigeration cycle when said expansion device is supplying said mixture of said refrigerant vapor and liquid to said evaporating coil inlet.

5 more elements

A vapor compression refrigeration system comprising:

a compressor for increasing the pressure and temperature of a refrigerant vapor, said compressor having an inlet and an outlet;
a condenser having an inlet in flow communication with the outlet of said compressor for liquefying pressurized refrigerant vapor received from said compressor;
an expansion device which, during a cooling mode of operation of said refrigeration system, is in flow communication with an outlet of said condenser for receiving liquid refrigerant from said condenser and expanding the same, said expansion device including a thermostatic expansion valve having an inlet and an outlet, the outlet of said thermostatic expansion valve being in series flow communication with an inlet to a multifunctional valve which includes an expansion chamber whereby liquid refrigerant supplied to said expansion device undergoes a two-stage expansion;
an evaporator including an evaporating coil having an inlet and an outlet, said evaporating coil being in a heat exchange relation with an air medium along substantially the entire length of said coil;
an evaporator feed line providing flow communication of said expansion device with said evaporating coil inlet;
a suction line providing flow communication of said evaporating coil outlet with said compressor inlet;
said expansion device and said evaporator feed line, during a cooling mode of operation of said vapor compression refrigeration system, being sized to convert a significant amount of said liquid form to a liquid and vapor mixture within said evaporator feed line and to provide said evaporating coil inlet with a refrigerant liquid and vapor mixture that includes a substantial vapor portion,
said evaporating coil being sized to provide refrigerant comprising liquid and vapor at said outlet of said evaporator coil during the portion of each refrigeration cycle when said expansion device is supplying said mixture of said refrigerant vapor and liquid to said evaporating coil inlet.

5 more elements

Dependencies are inferred from the claim text.