Flowrate determination system and method for a flow control valve

A method of monitoring flow of a fluid through a valve in a heating, ventilation, or air conditioning (HVAC) system, the method comprising:

• placing a flow control device within a fluid flow path, the flow control device comprising:
• a pressure-regulating valve comprising an inlet path and an outlet path,
• a moveable fluid barrier configured to adjust a size of an opening of the pressure-regulating valve,
• a control valve comprising a valve member and a valve stem coupled to the valve member;
• receiving pressure measurements from a first sensor for the pressure-regulating valve, based on linear displacement of the moveable fluid barrier;
• receiving position measurements from a second sensor, the position measurements based on linear and angular displacement of the valve stem;
• determining a flowrate based at least on measurements from the first sensor and measurements from the second sensor;
• determining an amount of energy provided by a heat exchanger;
• determining an error indicating that the flowrate is outside of an acceptable threshold;
• and
• initiating corrective action within the HVAC system to correct the error, wherein initiating corrective action comprises at least adjusting the valve stem based on the amount of energy and a factor related to the flowrate.

A flow control device for controlling flow in a heating, ventilation, or air conditioning (HVAC) system, the flow control device comprising:

• a pressure-regulating valve comprising an inlet path and an outlet path;
• a moveable fluid barrier configured to adjust a size of an opening of the pressure-regulating valve;
• a control valve comprising a valve member and a valve stem coupled to the valve member;
• a first sensor configured to obtain pressure measurements within the pressure-regulating valve based on linear displacement of the moveable fluid barrier;
• a second sensor configured to obtain linear and angular displacement measurements of the valve stem;
• a third sensor located proximate to an inlet of a heat exchanger upstream of the flow control device;
• a fourth sensor located proximate to an outlet of the heat exchanger;
• and
• a controller comprising a processing circuit configured to:
• determine a temperature differential of the heat exchanger based on measurements from the third sensor and the fourth sensor;
• determine a flowrate based at least on measurements from the first sensor and measurements from the second sensor;
• calculate energy throughput of the flow control device based on the temperature differential and the flowrate;
• and
• adjust the valve stem based on the energy throughput and a factor related to the flowrate.