Method of load distribution in a cascaded refrigeration process
OwnerWilliam R. Low, Donald L. Andress +1inventors
InventorsWilliam R. Low, Donald L. Andress, Clarence G. Houser
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Abstract
A process, apparatus and control methodology for transferring loads between drivers in adjacent refrigeration cycles in a cascaded refrigeration process has been developed thereby enabling more efficient driver operation. Load transfer is effected by cooling the higher boiling point refrigerant liquid prior to flashing via an indirect heat transfer with the lower boiling point refrigerant vapor in a adjacent cycle prior to compression of said stream.
Claims22
In a cascaded refrigeration process, the improvement comprising a process for transferring compressor loads from a driver in a first refrigerant cycle containing a higher boiling point refrigerant to a driver in a second refrigerant cycle containing a lower boiling point refrigerant comprising:
- (a) contacting a controlled amount of the higher boiling point refrigerant liquid in the first refrigeration cycle via an indirect heat transfer means with the lower boiling point refrigerant vapor in a second refrigeration cycle thereby producing a cooled refrigerant liquid and a heated refrigerant vapor;
- (b) flashing said subcooled refrigerant liquid thereby making available additional refrigerative cooling to the first refrigerant cycle;
- and
- (c) returning said heated refrigerant vapor to the compressor in the second refrigeration cycle.
An apparatus for transferring compressor loading from a driver in a first refrigeration cycle containing a higher boiling point refrigerant to a driver in a second refrigeration cycle containing a lower boiling point refrigerant, said apparatus comprising
- (a) a first conduit for flowing the higher boiling point refrigerant liquid to an indirect heat transfer means;
- (b) a second conduit for flowing the lower boiling point refrigerant vapor to said indirect heat transfer means;
- (c) a third conduit for flowing the higher boiling point refrigerant liquid from said indirect heat exchange means to a pressure reduction means in said first refrigeration cycle;
- (d) a fourth conduit connecting said first conduit to said third conduit so as to provide a bypass flow path around said indirect transfer means;
- (e) a fifth conduit for flowing said lower boiling point refrigerant vapor from said indirect heat transfer means to a compressor in said second refrigeration cycle;
- (f) said indirect heat transfer means;
- (g) said compressor;
- (h) said pressure reduction means;
- and
- (i) means for manipulating the relative flow rates of said higher boiling point refrigerant liquid through said fourth conduit and said indirect heat transfer means.
A control methodology for transferring loads between drivers in adjacent refrigeration cycles in a cascaded refrigeration process wherein a higher boiling point refrigerant liquid in one cycle is cooled prior to flashing by contacting via an indirect heat transfer means a lower boiling point refrigerant vapor in a adjacent cycle prior to compression of said vapor comprising
- (a) determining the loadings of the drivers for the higher boiling point and lower boiling point refrigeration cycles;
- (b) comparing the respective loadings of each driver thereby determining the direction of driver loading transfer for more efficient driver operation;
- (c) flowing at least a portion of the lower boiling point refrigerant vapor stream to an indirect heat transfer means thereby producing a heated vapor stream;
- (d) flowing said processed vapor stream to the low boiling point refrigerant compressor;
- (e) splitting the high boiling point refrigerant liquid stream into a first liquid stream and a second liquid stream;
- (f) flowing said liquid second stream to said indirect heat transfer means thereby producing a cooled second stream;
- and
- (g) controlling the relative flow of said first stream and said second stream responsive to step (b) above via a control valve wherein the flowrate of said second liquid stream is increased as load transfer to the lower boiling point refrigerant driver is increased.
Dependencies are inferred from the claim text.