Multi-Circuit Refrigerant System Utilizing Pulse Width Modulation Techniques

Abstract

A multi-circuit refrigerant system incorporates at least one component provided with a pulse width modulation control. This component can be controlled to adjust the capacity provided by the circuit incorporating the component. In this manner, the pulse width modulation component can be controlled to exactly tailor the capacity of that circuit to provide a total desired combined cooling capacity of the multiple circuits within the multi-circuit system configurations. In one embodiment, only one circuit in a multi-circuit refrigerant system incorporates a pulse width modulation controlled component. In another embodiment, a plurality of circuits are provided with pulse width modulation controlled components.

1 . A refrigerant system comprising:
 a plurality of circuits, with each of said circuits including a compressor, a condenser, an expansion device, and an evaporator; and   at least one of said circuits having at least one component provided with a pulse width modulation control.   
   
   
       2 . The refrigerant system as set forth in  claim 1 , wherein at least one of said plurality of circuits does not include a component with a pulse width modulation control. 
   
   
       3 . The refrigerant system as set forth in  claim 2 , wherein said at least one component is a suction modulation valve. 
   
   
       4 . The refrigerant system as set forth in  claim 1 , wherein at least two circuits each have a component with a pulse width modulation control. 
   
   
       5 . The refrigerant system as set forth in  claim 1 , wherein said at least one component is a suction modulation valve. 
   
   
       6 . The refrigerant system as set forth in  claim 1 , wherein said control of said at least one component is controlled to change the capacity of said compressor. 
   
   
       7 . The refrigerant system as set forth in  claim 6 , wherein said control allows two scroll members to move into and away from contact with each other to adjust capacity. 
   
   
       8 . The refrigerant system as set forth in  claim 1 , wherein at least one of said compressors is selected from the group comprising a screw compressor, a scroll compressor, a reciprocating compressor and a rotary compressor. 
   
   
       9 . The refrigerant system as set forth in  claim 1 , wherein said system is utilized as part of one of a commercial air conditioning or heat pump system, a rooftop system, a commercial chiller system, a residential air conditioning or heat pump system, a supermarket refrigeration system, a container refrigeration system and a truck-trailer refrigeration system. 
   
   
       10 . A method of operating a multi-circuit refrigerant system comprising the steps of:
 1) providing a plurality of circuits, with each of said circuits including a compressor, a condenser, an expansion device, and an evaporator; and   2) operating at least one component in at least one of said circuits with a pulse width modulation control.   
   
   
       11 . The method as set forth in  claim 10 , wherein at least one of said compressors is selected from the group comprising a screw compressor, a scroll compressor, a reciprocating compressor and a rotary compressor. 
   
   
       12 . The method as set forth in  claim 10 , wherein said system is utilized as part of one of a commercial air conditioning or heat pump system, a rooftop system, a commercial chiller system, a residential air conditioning or heat pump system, a supermarket refrigeration system, a container refrigeration system and a truck-trailer refrigeration system. 
   
   
       13 . The method as set forth in  claim 10 , wherein at least one of said plurality of circuits does not include a component with a pulse width modulation control. 
   
   
       14 . The method as set forth in  claim 13 , wherein said at least one component is a suction modulation valve. 
   
   
       15 . The method as set forth in  claim 10 , wherein at least two circuits each have a component operational with a pulse width modulation control. 
   
   
       16 . The method as set forth in  claim 10 , wherein said at least one component is a suction modulation valve. 
   
   
       17 . The method as set forth in  claim 10 , wherein said control changes the capacity of said compressor. 
   
   
       18 . The method as set forth in  claim 17 , wherein the pulse width modulation allows two scroll members to move into and away from contact with each other to adjust capacity. 
   
   
       19 . The refrigerant system as set forth in  claim 1 , wherein each of said plurality of circuits has its own dedicated compressor, condenser, expansion device, and evaporator. 
   
   
       20 . The method as set forth in  claim 11 , wherein each of said plurality of circuits is provided with its own compressor, condenser, expansion device and evaporator.