Capacity modulated compressor

Abstract

A heat pump system may include first and second heat exchangers, a compressor, and a fluid conduit. The compressor may include a capacity modulation system providing first, second, and third capacities of the compressor. The second capacity may be less than the first capacity and greater than the third capacity. The fluid conduit may provide fluid communication between the first and second heat exchangers and the compressor. The fluid conduit may define a first flow path from the compressor to the first heat exchanger and from the first heat exchanger to the second heat exchanger during a cooling mode and a second flow path from the compressor to the second heat exchanger and from the second heat exchanger to the first heat exchanger during a heating mode. The compressor may operate at the first capacity during the heating mode and at the second capacity during the cooling mode.

1 . A compressor comprising:
 a shell;   a compression mechanism contained within said shell and including first and second scroll members supported for relative orbital displacement therebetween, said first and second scroll members each including an end plate having spiral wraps extending therefrom, said spiral wraps of said first and second scroll members meshingly engaged with one another and forming a plurality of pockets;   a first passage disposed in said first scroll member and extending from an exterior portion of said first scroll member into a first of said pockets;   a second passage disposed in said first scroll member and extending into a second of said pockets disposed radially inwardly relative to said first pocket; and   a valve assembly operable to selectively open and close said first and second passages to provide a first operating capacity wherein both of said first and second passages are closed, a second operating capacity wherein said first passage is open and said second passage is closed, and a third operating capacity wherein said second passage is open, said compressor disposed in a heat pump system wherein said first operating capacity corresponds to a heating mode of the heat pump system and said third operating capacity corresponds to a cooling mode of the heat pump system.   
   
   
       2 . The compressor of  claim 1 , wherein said compression mechanism operates at a cooling mode system rated capacity when operated at said second operating capacity. 
   
   
       3 . The compressor of  claim 2 , wherein said second operating capacity is less than said first operating capacity and greater than said third operating capacity. 
   
   
       4 . The compressor of  claim 3 , wherein said first operating capacity is ten to thirty-five percent greater than said second operating capacity. 
   
   
       5 . The compressor of  claim 3 , wherein said third operating capacity is ten to thirty-five percent less than said second operating capacity. 
   
   
       6 . The compressor of  claim 1 , further comprising third and fourth passages disposed in said first scroll member, said third passage extending from an exterior portion of said first scroll member into a third of said pockets and said fourth passage extending from an exterior portion of said first scroll member into a fourth of said pockets, said fourth pocket being disposed radially inwardly relative to said first and third pockets. 
   
   
       7 . The compressor of  claim 6 , wherein said first operating capacity includes closing said first, second, third, and fourth passages. 
   
   
       8 . The compressor of  claim 6 , wherein said second operating capacity includes closing said second and fourth passages and opening said first and third passages. 
   
   
       9 . The compressor of  claim 6 , wherein said third operating capacity includes opening said second and fourth passages. 
   
   
       10 . The compressor of  claim 9 , wherein said third operating capacity includes opening said first and third passages. 
   
   
       11 . The compressor of  claim 1 , wherein said first scroll member is a non-orbiting scroll member. 
   
   
       12 . The compressor of  claim 1 , wherein said third operating capacity includes opening said first passage. 
   
   
       13 . The compressor of  claim 1 , wherein said valve assembly includes a modulation ring disposed around an exterior sidewall of said first scroll member and displaceable between first, second, and third positions corresponding to said first, second, and third operating capacities to selectively open said first and second passages. 
   
   
       14 . The compressor of  claim 13 , wherein said valve assembly includes a solenoid to displace said modulation ring between said first, second, and third positions. 
   
   
       15 . A heat pump system comprising:
 a first heat exchanger;   a second heat exchanger;   a compressor including a capacity modulation system providing first, second, and third operating capacities of said compressor, said second operating capacity being less than said first operating capacity and greater than said third operating capacity; and   a fluid conduit providing fluid communication between said first heat exchanger, said second heat exchanger, and said compressor, said fluid conduit defining a first flow path from said compressor to said first heat exchanger and from said first heat exchanger to said second heat exchanger when operating in a cooling mode and a second flow path from said compressor to said second heat exchanger and from said second heat exchanger to said first heat exchanger when operating in a heating mode, said compressor operating at said first operating capacity during said heating mode and operating at said second operating capacity during said cooling mode.   
   
   
       16 . The heat pump system of  claim 15 , wherein said compressor includes a system rated capacity for said cooling mode corresponding to said second operating capacity. 
   
   
       17 . The heat pump system of  claim 15 , wherein said first operating capacity is ten to thirty-five percent greater than said second operating capacity. 
   
   
       18 . The heat pump system of  claim 15 , wherein said third operating capacity is ten to thirty-five percent less than said second operating capacity. 
   
   
       19 . The heat pump system of  claim 15 , wherein said compressor is a scroll compressor. 
   
   
       20 . A method comprising:
 sealing a first leak path in communication with a first of pockets formed by meshingly engaged wraps of first and second scroll members of a scroll compressor operating at a first pressure and sealing a second leak path in communication with a second of the pockets formed by the meshingly engaged wraps of the first and second scroll members of the scroll compressor operating at a second pressure greater than the first pressure to operate the compressor at a first operating capacity during a heating mode of a heat pump system;   opening the first leak path and closing the second leak path to operate the compressor at a second operating capacity that is reduced from the first operating capacity during a cooling mode of the heat pump system; and   opening the second leak path to operate the compressor at a third operating capacity that is reduced from the second operating capacity during the cooling mode.   
   
   
       21 . The method of  claim 20 , wherein said operating the compressor at the first operating capacity includes operating the compressor at a capacity that is at least ten percent greater than the second operating capacity. 
   
   
       22 . The method of  claim 20 , wherein said operating the compressor at the third operating capacity includes operating the compressor at a capacity that is at least ten percent less than the second operating capacity. 
   
   
       23 . The method of  claim 20 , wherein a seasonal energy efficiency ratio (SEER) rating is increased relative to operation at the second operating capacity during the cooling mode through operation of the compressor at the third operating capacity. 
   
   
       24 . The method of  claim 20 , wherein a heating seasonal performance factor (HSPF) rating is increased relative to operation at the second operating capacity during the heating mode through operation of the compressor at the first operating capacity. 
   
   
       25 . The method of  claim 20 , wherein the second operating capacity is a system rated capacity of the cooling mode. 
   
   
       26 . The method of  claim 20 , further comprising opening the first leak path to operate the compressor at the third operating capacity.