Flash tank design and control for heat pumps

Abstract

A flash tank for a heat pump operable in a heating mode and a cooling mode includes a shell having a middle portion disposed between a top portion and a bottom portion, with the top portion, bottom portion, and middle portion cooperating to define an inner volume of the shell. A first port is in fluid communication with the inner volume and functions as an inlet in the heating mode and as an outlet in the cooling mode. A second port is in fluid communication with the inner volume and functions as an inlet in the cooling mode and as an outlet in the heating mode. Flow control devices and check valves are fluidly coupled to control the tank as a flash tank in heating mode and as a receiver in cooling mode.

1 . A flash tank comprising: 
 a shell having a middle portion disposed between a top portion and a bottom portion, said top portion, bottom portion, and middle portion cooperating to define an inner volume;    a first port in fluid communication with said inner volume and operable as an inlet in the heating mode and as an outlet in the cooling mode; and    a second port in fluid communication with said inner volume and operable as an inlet in the cooling mode and as an outlet in the heating mode.    
   
   
       2 . The flash tank of  claim 1 , wherein the shell includes a height to diameter aspect ratio of approximately four to six.  
   
   
       3 . The flash tank of  claim 1 , wherein said first port is formed through said middle portion of said shell.  
   
   
       4 - 5 . (canceled)  
   
   
       6 . The flash tank of  claim 1 , wherein said first port is formed tangentially to an inner surface of said shell.  
   
   
       7 . The flash tank of  claim 1 , wherein said first port includes a first portion formed perpendicular to said shell and a second portion formed substantially parallel to said shell such that said first portion and said second portion cooperate to define a substantially L-shape.  
   
   
       8 . (canceled)  
   
   
       9 . The flash tank of  claim 1 , further comprising internal baffles disposed within said shell.  
   
   
       10 - 13 . (canceled)  
   
   
       14 . The flash tank of  claim 1 , wherein said second port is disposed in said bottom portion of said shell.  
   
   
       15 . The flash tank of  claim 1 , further comprising a disk disposed within said shell to separate a liquid portion of the shell from a vapor portion of the shell.  
   
   
       16 - 21 . (canceled)  
   
   
       22 . The flash tank of  claim 1 , further comprising a recirculation tube formed through said middle portion of said shell to remove liquid from said shell when said liquid reaches a predetermined level within said shell.  
   
   
       23 . (canceled)  
   
   
       24 . The flash tank of  claim 1 , further comprising a sight glass formed through said shell for viewing a pre-determined fluid level within said shell.  
   
   
       25 . The flash tank of  claim 1 , further comprising a liquid level sensor for determining a fluid lever within said shell.  
   
   
       26 . A heat pump system operable in a heating mode and a cooling mode comprising: 
 a first heat exchanger;    a second heat exchanger in fluid communication with said first heat exchanger;    a compressor in fluid communication with each of said first and second heat exchangers; and    a tank in fluid communication with each of said first and second heat exchangers and said compressor, said tank including: 
 a shell having a middle portion disposed between a top portion and a bottom portion, said top portion, bottom portion, and middle portion cooperating to define an inner volume;  
 a first port receiving fluid from said first heat exchanger and in fluid communication with said inner volume, said first port operable as an inlet in the heating mode and as an outlet in the cooling mode; and  
 a second port receiving fluid from said second heat exchanger and in fluid communication with said inner volume, said second port operable as an inlet in the cooling mode and as an outlet in the heating mode.  
   
   
   
       27 . The heat pump system of  claim 26 , further comprising a first control device disposed between said first port and said first heat exchanger.  
   
   
       28 . The heat pump system of  claim 27 , wherein said first control device is one of a thermal expansion valve, an electronic expansion valve, a fixed orifice, or a single, bi-directional electronic expansion valve.  
   
   
       29 - 31 . (canceled)  
   
   
       32 . The heat pump system of  claim 27 , further comprising a check valve disposed between said first port and said first heat exchanger and operable to allow fluid to bypass said first control device in said cooling mode and direct said fluid into said first control device in said heating mode.  
   
   
       33 . The heat pump system of  claim 27 , further comprising a second control device disposed between said first port and said first heat exchanger.  
   
   
       34 . The heat pump system of  claim 33 , wherein said first and second control devices are selected from the group comprising: a thermal expansion valve, an electronic expansion valve, a fixed orifice, or a single, bi-directional electronic expansion valve.  
   
   
       35 - 36 . (canceled)  
   
   
       37 . The heat pump system of  claim 33 , further comprising a check valve disposed between said first port and said first heat exchanger and operable to allow fluid to bypass said second control device in said heating mode and direct said fluid into said second control device in said cooling mode.  
   
   
       38 . The heat pump system of  claim 27 , further comprising a third control device disposed between said second port and said second heat exchanger.  
   
   
       39 . The heat pump system of  claim 38 , wherein said first and third control devices are selected from the group comprising: a thermal expansion valve, an electronic expansion valve, a fixed orifice, or a single, bi-directional electronic expansion valve.  
   
   
       40 - 41 . (canceled)  
   
   
       42 . The heat pump system of  claim 38 , further comprising a check valve disposed between said second port and said second heat exchanger and operable to allow fluid to bypass said third control device in said cooling mode and direct said fluid into said third control device in said heating mode.  
   
   
       43 . The heat pump system of  claim 26 , further comprising an injection line extending from said tank to said compressor.  
   
   
       44 . The heat pump system of  claim 43 , further comprising a fourth control device disposed on said injection line to control fluid from said tank to said compressor.  
   
   
       45 . (canceled)  
   
   
       46 . The heat pump system of  claim 44 , wherein said fourth control device is a solenoid valve.  
   
   
       47 . The heat pump of  claim 44 , wherein said fourth control device is controlled based on at least one of outdoor ambient temperature, compressor discharge temperature, indoor heat exchanger fan speed, thermostat stage demand, and a reversing valve signal.  
   
   
       48 - 55 . (canceled)  
   
   
       56 . The heat pump system of  claim 38 , further comprising a fifth control device disposed between said second port and said second heat exchanger.  
   
   
       57 . The heat pump system of  claim 56 , wherein said first third, and fifth control devices are selected from the group comprising: a thermal expansion valve, an electronic expansion valve, a fixed orifice, or a single, bi-directional electronic expansion valve.  
   
   
       58 - 59 . (canceled)  
   
   
       60 . The heat pump system of  claim 56 , further comprising a check valve disposed between said second port and said second heat exchanger and operable to allow fluid to bypass said fifth control device in said heating mode and direct said fluid into said fifth control device in said cooling mode.  
   
   
       61 - 92 . (canceled)  
   
   
       93 . The heat pump system of  claim 56 , further comprising a second control device disposed between said first port and said first heat exchanger.  
   
   
       94 . The heat pump system of  claim 93 , wherein said first, second, third, and fifth control devices are selected from the group comprising: a thermal expansion valve, an electronic expansion valve, a fixed orifice, or a single, bi-directional electronic expansion valve.