Chiller system with serial flow evaporators

Abstract

A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system includes a first refrigerant circuit having a first evaporator configured to place a first refrigerant in a heat exchange relationship with a conditioning fluid, where the first evaporator includes a first set of first tubes and a second set of first tubes configured to direct the conditioning fluid through the first evaporator. The HVAC&R system also includes a second refrigerant circuit having a second evaporator configured to place a second refrigerant in a heat exchange relationship with the conditioning fluid, where the second evaporator includes a first set of second tubes and a second set of second tubes configured to direct the conditioning fluid through the second evaporator. The HVAC&R system further includes a conditioning fluid circuit configured to circulate the conditioning fluid serially through the first set of first tubes, the second set of first tubes, the first set of second tubes, and the second set of second tubes.

1 . A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system, comprising:
 a first refrigerant circuit comprising a first evaporator configured to place a first refrigerant in a heat exchange relationship with a conditioning fluid, wherein the first evaporator comprises a first set of first tubes and a second set of first tubes configured to direct the conditioning fluid through the first evaporator;   a second refrigerant circuit comprising a second evaporator configured to place a second refrigerant in a heat exchange relationship with the conditioning fluid, wherein the second evaporator comprises a first set of second tubes and a second set of second tubes configured to direct the conditioning fluid through the second evaporator; and   a conditioning fluid circuit configured to circulate the conditioning fluid serially through the first set of first tubes, the second set of first tubes, the first set of second tubes, and the second set of second tubes.   
     
     
         2 . The HVAC&R system of  claim 1 , wherein the first set of first tubes defines a lower pass of the first evaporator, and the second set of first tubes defines an upper pass of the first evaporator. 
     
     
         3 . The HVAC&R system of  claim 2 , wherein the first evaporator comprises a water box configured to receive the conditioning fluid from the first set of first tubes, reverse a flow direction of the conditioning fluid through the first evaporator, and direct the conditioning fluid into the second set of first tubes. 
     
     
         4 . The HVAC&R system of  claim 2 , wherein the first set of second tubes defines a lower pass of the second evaporator, and the second set of second tubes defines an upper pass of the second evaporator. 
     
     
         5 . The HVAC&R system of  claim 4 , wherein the conditioning fluid circuit comprises a conduit extending from an outlet of the second evaporator to an inlet of the first evaporator, the outlet of the second evaporator is configured to direct the conditioning fluid from the second set of second tubes toward the conduit, and the inlet of the first evaporator is configured to direct the conditioning fluid from the conduit toward the first set of first tubes. 
     
     
         6 . The HVAC&R system of  claim 1 , wherein the first evaporator comprises an outlet, the second evaporator comprises an inlet, the outlet is configured to direct the conditioning fluid toward a cooling load, and the inlet is configured to receive the conditioning fluid from the cooling load. 
     
     
         7 . The HVAC&R system of  claim 1 , wherein the first evaporator and the second evaporator are arranged in an end-to-end configuration relative to one another. 
     
     
         8 . The HVAC&R system of  claim 1 , wherein the first evaporator and the second evaporator are arranged in a side-by-side configuration relative to one another. 
     
     
         9 . The HVAC&R system of  claim 1 , comprising a chiller having the first refrigerant circuit and the second refrigerant circuit, wherein the first refrigerant circuit comprises a first condenser configured to place the first refrigerant in a heat exchange relationship with ambient air, and the second refrigerant circuit comprises a second condenser configured to place the second refrigerant in a heat exchange relationship with ambient air. 
     
     
         10 . A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system, comprising:
 a first evaporator comprising a first lower tube bundle and a first upper tube bundle, wherein the first lower tube bundle and the first upper tube bundle are each configured to place a conditioning fluid in a heat exchange relationship with a first refrigerant;   a second evaporator comprising a second lower tube bundle and a second upper tube bundle, wherein the second lower tube bundle and the second upper tube bundle are each configured to place the conditioning fluid in a heat exchange relationship with a second refrigerant;   a conduit fluidly extending between the first evaporator and the second evaporator and fluidly coupling the first lower tube bundle and the second upper tube bundle; and   a conditioning fluid circuit configured to circulate the conditioning fluid serially through the second lower tube bundle, the second upper tube bundle, the conduit, the first lower tube bundle, and the first upper tube bundle.   
     
     
         11 . The HVAC&R system of  claim 10 , wherein the conditioning fluid circuit is configured to direct the conditioning fluid from a cooling load to the second lower tube bundle and from the first upper tube bundle to the cooling load. 
     
     
         12 . The HVAC&R system of  claim 10 , wherein the first lower tube bundle defines a first pass of the first evaporator, and the first upper tube bundle defines a second pass of the first evaporator. 
     
     
         13 . The HVAC&R system of  claim 12 , wherein the second lower tube bundle defines a first pass of the second evaporator, and the second upper tube bundle defines a second pass of the second evaporator. 
     
     
         14 . The HVAC&R system of  claim 10 , comprising:
 a first refrigerant circuit comprising the first evaporator, a first compressor, and a first condenser, wherein the first condenser is configured to place the first refrigerant in a heat exchange relationship with ambient air; and   a second refrigerant circuit comprising the second evaporator, a second compressor, and a second condenser, wherein the second condenser is configured to place the second refrigerant in a heat exchange relationship with ambient air,   wherein the first refrigerant circuit and the second refrigerant circuit are fluidly separate from one another.   
     
     
         15 . A chiller system, comprising:
 a first refrigerant circuit comprising a first evaporator configured to place a first refrigerant in a heat exchange relationship with a conditioning fluid, wherein the first evaporator comprises a first plurality of first tubes and a second plurality of first tubes configured to direct the conditioning fluid through the first evaporator, wherein the first plurality of first tubes defines a lower pass of the first evaporator, and the second plurality of first tubes defines an upper pass of the first evaporator;   a second refrigerant circuit comprising a second evaporator configured to place a second refrigerant in a heat exchange relationship with the conditioning fluid, wherein the second evaporator comprises a first plurality of second tubes and a second plurality of second tubes configured to direct the conditioning fluid through the second evaporator, wherein the first plurality of second tubes defines a lower pass of the second evaporator, and the second plurality of second tubes defines an upper pass of the second evaporator; and   a conduit extending between and fluidly coupling the second plurality of second tubes and the first plurality of first tubes.   
     
     
         16 . The chiller system of  claim 15 , wherein the first evaporator, the second evaporator, and the conduit are configured to direct the conditioning fluid serially through the second plurality of second tubes, the first plurality of second tubes, the conduit, the first plurality of first tubes, and the second plurality of first tubes. 
     
     
         17 . The chiller system of  claim 15 , wherein the first refrigerant circuit comprises a first air-cooled condenser, the second refrigerant circuit comprises a second air-cooled condenser, and the first refrigerant circuit and the second refrigerant circuit are fluidly separate from one another. 
     
     
         18 . The chiller system of  claim 15 , wherein the first evaporator and the second evaporator are positioned in an end-to-end arrangement relative to one another. 
     
     
         19 . The chiller system of  claim 15 , wherein the first evaporator and the second evaporator are positioned in a side-by-side arrangement relative to one another. 
     
     
         20 . The chiller system of  claim 15 , comprising a controller configured to regulate operation of the first refrigerant circuit and the second refrigerant circuit independently of one another based on feedback received from one or more sensors of the chiller system.