Systems and methods for control of superheat from a subcooler

A method of operating a heating, ventilation, air conditioning, and refrigeration (HVACR) circuit, comprising:

• providing a first working fluid flow through a suction line heat exchanger, wherein the first working fluid flow is a working fluid flow from a first heat exchanger to a suction of a compressor;
• providing a second working fluid flow through the suction line heat exchanger, separate from the first working fluid flow, wherein the second working fluid flow is a working fluid flow from a second heat exchanger to an expander, and the first working fluid flow and the second working fluid flow exchange heat in the suction line heat exchanger;
• receiving a first temperature of the first working fluid flow at a position directly upstream of the suction line heat exchanger;
• receiving a second temperature of the first working fluid flow at a position directly downstream of the suction line heat exchanger;
• determining a superheat generation based on the first temperature and the second temperature;
• controlling a quantity of flow of the second working fluid flow through the suction line heat exchanger based on the superheat generation and a threshold superheat value.