US 11,913,690 B2
Refrigeration system with efficient expansion device control, liquid refrigerant return, oil return, and evaporator defrost
Senthilkumar Kandappa Goundar Shanmugam, Covington, GA (US); and Manu Mital, Covington, GA (US)
Assigned to Hill Phoenix, Inc., Conyers, GA (US)
Filed by Hill Phoenix, Inc., Conyers, GA (US)
Filed on Nov. 21, 2022, as Appl. No. 17/991,196.
Application 17/991,196 is a division of application No. 16/871,153, filed on May 11, 2020, granted, now 11,536,498.
Prior Publication US 2023/0112193 A1, Apr. 13, 2023
Int. Cl. F25B 49/02 (2006.01); F25B 41/31 (2021.01); F25B 47/02 (2006.01); F25B 39/02 (2006.01); F25B 43/02 (2006.01)
CPC F25B 41/31 (2021.01) [F25B 39/028 (2013.01); F25B 43/02 (2013.01); F25B 47/02 (2013.01); F25B 49/02 (2013.01); F25B 2400/23 (2013.01); F25B 2600/05 (2013.01); F25B 2600/2513 (2013.01); F25B 2700/03 (2013.01); F25B 2700/04 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A refrigeration system comprising:
a compressor configured to circulate a refrigerant within the refrigeration system;
an evaporator configured to transfer heat into the refrigerant within the evaporator to provide cooling for a temperature-controlled space;
a liquid/vapor separator configured to separate the refrigerant into vapor refrigerant and liquid refrigerant, the liquid/vapor separator comprising:
an inlet fluidly coupled to an outlet of the evaporator and configured to receive the refrigerant from the evaporator;
a vapor refrigerant outlet fluidly coupled to the compressor and configured to discharge the vapor refrigerant to the compressor; and
a liquid refrigerant outlet fluidly coupled to the evaporator and configured to return the liquid refrigerant to the evaporator;
a liquid level sensor configured to measure a level of liquid accumulated within the liquid/vapor separator;
an oil level sensor configured to measure a level of oil accumulated within the liquid/vapor separator;
a controller configured to initiate a liquid refrigerant return process in response to at least one of i) the level of liquid accumulated within the liquid/vapor separator exceeding a threshold value or ii) a calculated value based on the level of liquid accumulated within the liquid/vapor separator exceeding the threshold value, the level of liquid comprising a total level of oil and the liquid refrigerant accumulated within the liquid/vapor separator, the controller configured to:
determine a level of liquid refrigerant accumulated within the liquid/vapor separator by subtracting the level of oil from the total level of oil and liquid refrigerant; and
initiate the liquid refrigerant return process in response to the level of liquid refrigerant accumulated within the liquid/vapor separator exceeding the threshold value.