Hybrid serial counterflow dual refrigerant circuit chiller

Abstract

A dual refrigerant circuit chiller ( 10 ) has a first refrigerant circuit ( 100 ) including a first condenser ( 130 ) and a first evaporator ( 140 ), a second refrigerant circuit ( 200 ) including a second condenser ( 230 ) and a second evaporator ( 240 ), a condenser assembly ( 30 ) including the first condenser ( 130 ) and the second condenser ( 230 ) interconnected in a series cooling fluid circuit, and an evaporator assembly ( 40 ) including the first evaporator ( 140 ) and the second evaporator ( 240 ) interconnected in a series fluid circuit with a waterbox ( 50 ) disposed intermediate the first evaporator ( 140 ) and the second evaporator ( 240 ). The evaporator assembly ( 40 ) has a chilled fluid inlet ( 45 ) and a chilled fluid outlet ( 43 ) that are disposed at opposite longitudinal ends of the evaporator assembly ( 40 ). Each of the first and second evaporators ( 140, 240 ) embodies a multiple pass circuit fluid-to-refrigerant heat exchanger.

1 . A dual refrigerant circuit chiller comprising:
 a first refrigerant circuit including a first condenser and a first evaporator;   a second refrigerant circuit including a second condenser and a second evaporator,   a condenser assembly including the first condenser and the second condenser interconnected in a series cooling fluid circuit, the condenser assembly having a cooling fluid inlet in fluid communication with the second condenser and a cooling fluid outlet in fluid communication with the first condenser; and   an evaporator assembly including the first evaporator and the second evaporator interconnected in a series fluid circuit and a waterbox disposed intermediate the first evaporator and the second evaporator, the evaporator assembly having a circuit fluid inlet in fluid communication with the first evaporator and a circuit fluid outlet in fluid communication with the second evaporator, the first evaporator having a multiple pass circuit fluid-to-refrigerant heat exchanger having an outlet in fluid communication with the waterbox and an inlet in fluid communication with the circuit fluid inlet of the evaporator assembly, the second evaporator having a multiple pass circuit fluid-to-refrigerant heat exchanger having an inlet in fluid communication with the waterbox and an outlet in fluid communication with the circuit fluid outlet of the evaporator assembly, the circuit fluid inlet and the circuit fluid outlet disposed at opposite longitudinal ends of the evaporator assembly.   
     
     
         2 . The dual refrigerant circuit chiller as recited in  claim 1  wherein the circuit fluid-to-refrigerant heat exchanger of the first evaporator and the circuit fluid-to-refrigerant heat exchanger of the second evaporator each comprise a three pass tube bundle heat exchanger. 
     
     
         3 . The dual refrigerant circuit chiller as recited in  claim 1  wherein the cooling fluid is cooling water and the circuit fluid is chiller water. 
     
     
         4 . The dual refrigerant circuit chiller as recited in  claim 1  wherein the condenser assembly includes a waterbox disposed intermediate the first condenser and the second condenser, a multiple pass cooling fluid-to-refrigerant heat exchanger in the second condenser having an outlet in fluid communication with the waterbox and an inlet in fluid communication with the cooling fluid inlet of the condenser assembly, and a multiple pass cooling fluid-to-refrigerant heat exchanger in the first condenser having an inlet in fluid communication with the waterbox and an outlet in fluid communication with the cooling fluid outlet of the condenser assembly, the cooling fluid inlet and the cooling fluid outlet disposed at opposite longitudinal ends of the condenser assembly. 
     
     
         5 . The dual refrigerant circuit chiller as recited in  claim 1  wherein the evaporator assembly further includes a first bypass conduit having an inlet in fluid communication with the circuit fluid inlet of the evaporator assembly and an outlet in fluid communication with a first chamber of the waterbox, and wherein the multiple pass circuit fluid-to-refrigerant heat exchanger of the first evaporator has an inlet in fluid communication with the first chamber of the waterbox and an outlet in fluid communication with a second chamber of the waterbox. 
     
     
         6 . The dual refrigerant circuit chiller as recited in  claim 5  wherein the evaporator assembly further includes a second bypass conduit having an outlet in fluid communication with the circuit fluid outlet of the evaporator assembly and an inlet in fluid communication with a third chamber of the waterbox, and wherein the multiple pass circuit fluid-to-refrigerant heat exchanger of the second evaporator has an inlet in fluid communication with the second chamber of the waterbox and an outlet in fluid communication with a third chamber of the waterbox. 
     
     
         7 . A dual refrigerant circuit chiller comprising:
 a first refrigerant circuit including a first condenser and a first evaporator;   a second refrigerant circuit including a second condenser and a second evaporator,   a condenser assembly including the first condenser and the second condenser interconnected in a series cooling fluid circuit, the condenser assembly having a cooling fluid inlet in fluid communication with the second condenser and a cooling fluid outlet in fluid communication with the first condenser; and   an evaporator assembly including the first evaporator and the second evaporator interconnected in a series fluid circuit and a waterbox disposed intermediate the first evaporator and the second evaporator, the waterbox having a first chamber, a second chamber and a third chamber, the evaporator assembly having:   a circuit fluid inlet and the circuit fluid outlet disposed at opposite longitudinal ends of the evaporator assembly;   a first bypass conduit having an inlet in fluid communication with the circuit fluid inlet of the evaporator assembly and an outlet in fluid communication with the first chamber of the waterbox;   a first multiple pass circuit fluid-to-refrigerant heat exchanger disposed in the first evaporator having an inlet in fluid communication with the first chamber of the waterbox and an outlet in fluid communication with the second chamber of the waterbox;   a second bypass conduit having an outlet in fluid communication with the circuit fluid outlet of the evaporator assembly and an inlet in fluid communication with the third chamber of the waterbox;   a second multiple pass circuit fluid-to-refrigerant heat exchanger of the second evaporator has an inlet in fluid communication with the second chamber of the waterbox and an outlet in fluid communication with the third chamber of the waterbox.   
     
     
         8 . The dual refrigerant circuit chiller as recited in  claim 7  wherein the circuit fluid-to-refrigerant heat exchanger of the first evaporator and the circuit fluid-to-refrigerant heat exchanger of the second evaporator each comprise a two pass tube bundle heat exchanger. 
     
     
         9 . The dual refrigerant circuit chiller as recited in  claim 7  wherein the cooling fluid is cooling water and the circuit fluid is water. 
     
     
         10 . The dual refrigerant circuit chiller as recited in  claim 7  wherein the cooling fluid is cooling water and the circuit fluid is brine. 
     
     
         11 . The dual refrigerant circuit chiller as recited in  claim 7  wherein the condenser assembly includes a waterbox disposed intermediate the first condenser and the second condenser, a multiple pass cooling fluid-to-refrigerant heat exchanger in the second condenser having an outlet in fluid communication with the waterbox and an inlet in fluid communication with the cooling fluid inlet of the condenser assembly, and a multiple pass cooling fluid-to-refrigerant heat exchanger in the first condenser having an inlet in fluid communication with the waterbox and an outlet in fluid communication with the cooling fluid outlet of the condenser assembly, the cooling fluid inlet and the cooling fluid outlet disposed at opposite longitudinal ends of the condenser assembly. 
     
     
         12 . The dual refrigerant circuit chiller as recited in  claim 7  wherein the cooling fluid is cooling water and the circuit fluid is brine. 
     
     
         13 . The dual refrigerant circuit chiller as recited in  claim 1  wherein the intermediate waterbox is sectioned into a first chamber, a second chamber, and a third chamber. 
     
     
         14 . The dual refrigerant circuit chiller as recited in  claim 1  wherein the second chamber of the intermediate waterbox provides a generally vertical flow passage through the waterbox. 
     
     
         15 . The dual refrigerant circuit chiller as recited in  claim 7  wherein the first bypass conduit extends externally of the evaporator assembly at a first end of the evaporator assembly for connection to a fluid line for receiving circuit fluid and the second bypass conduit extends externally of the evaporator assembly at a second end of the evaporator assembly for connection to a fluid line for discharging circuit fluid. 
     
     
         16 . The dual refrigerant circuit chiller as recited in  claim 7  wherein the condenser assembly includes:
 a waterbox disposed intermediate the first condenser and the second condenser, the waterbox having a first chamber, a second chamber, and a third chamber; 
 a first bypass conduit having an inlet in fluid communication with the cooling fluid inlet of the condenser assembly and an outlet in fluid communication with the first chamber of the waterbox; 
 a first multiple pass cooling fluid-to-refrigerant heat exchanger disposed in the second condenser having an inlet in fluid communication with the first chamber of the waterbox and an outlet in fluid communication with the second chamber of the waterbox; 
 a second bypass conduit having an outlet in fluid communication with the cooling fluid outlet of the condenser assembly and an inlet in fluid communication with the third chamber of the waterbox; 
 a second multiple pass cooling fluid-to-refrigerant heat exchanger disposed in the first condenser having an inlet in fluid communication with the second chamber of the waterbox and an outlet in fluid communication with the third chamber of the waterbox. 
 
     
     
         17 . The dual refrigerant circuit chiller as recited in  claim 16  wherein the first bypass conduit extends externally of the condenser assembly at a first end of the condenser assembly for receiving cooling fluid and the second bypass conduit extends externally of the condenser assembly at a second end of the condenser assembly for discharging cooling fluid.