Refrigeration arrangement and methods for reducing charge migration

1. A refrigerator appliance, comprising:

a first refrigeration compartment;

a condenser;

a first and a second evaporator, the first evaporator in thermal communication with the first refrigeration compartment;

a refrigerant;

a compressor;

a refrigerant circuit arranged to allow flow of the refrigerant between the condenser, the evaporators and the compressor, the circuit comprising a first set of primary and secondary evaporator conduits arranged in parallel between the condenser and the first evaporator and a second set of primary and secondary evaporator conduits arranged in parallel between the condenser and the second evaporator;

a primary pressure reducing device arranged within each primary evaporator conduit and a secondary pressure reducing device arranged within each secondary evaporator conduit, each of the primary pressure reducing devices set at a different pressure reduction levels than each of the secondary pressure reducing devices;

a first suction line heat exchanger in thermal contact with the primary pressure reducing device and not in contact with the secondary pressure reducing device, the first suction line heat exchanger configured to transfer heat within the refrigerant circuit and arranged within the first set of evaporator conduits;

a second suction line heat exchanger in thermal contact with the primary pressure reducing device and not in contact with the secondary pressure reducing device, the second suction line heat exchanger configured to transfer heat within the refrigerant circuit and arranged within the second set of evaporator conduits;

a valve system in the first and second set of evaporator conduits capable of selectively directing or restricting flow of the refrigerant through each one, or all, of the pressure reducing devices; and

a controller for controlling the valve system and the compressor to maintain the first refrigeration compartment at any of a plurality of selectable temperatures.

2. The refrigerator appliance according to claim 1 , wherein the pressure reducing devices are selected from the group consisting of capillary tubes, expansion valves, orifice restrictors and needle valves.

3. The refrigerator appliance according to claim 1 , wherein the valve system comprises a three-way valve.

4. The refrigerator appliance according to claim 1 , wherein the compressor is a variable capacity compressor.

5. The refrigerator appliance according to claim 1 , further comprising:

a second refrigeration compartment, wherein the first refrigeration compartment is maintained at a temperature below 0° centigrade and the second refrigeration compartment is maintained at a temperature above 0° centigrade, the first evaporator is in thermal communication with the first refrigeration compartment, the second evaporator is in thermal communication with the second refrigeration compartment, and the controller for controlling the valve system maintains the first and second refrigeration compartments at any of a plurality of selectable temperatures.

6. The refrigerator appliance according to claim 1 , further comprising:

a check valve in the circuit arranged to block flow of the refrigerant from the condenser to the compressor; and

a check valve in the circuit arranged to block flow of the refrigerant from the exit of the second evaporator into the first evaporator.

7. The refrigerator appliance according to claim 1 , wherein the compressor is selected from the group consisting of a variable speed compressor, a linear compressor and a two-speed compressor.

8. The refrigerator appliance according to claim 2 , wherein the pressure reducing devices are capillary tubes.

9. The refrigerator appliance according to claim 1 , further comprising:

an evaporator fan and a condenser fan, the evaporator fan in thermal communication with the first refrigeration compartment.