Controller and method for managing a flow unit

A method of a controller for managing a flow unit, the method comprising:

• calibrating the controller of the flow unit comprising:
• establishing a calibration pressure drop at full open based on a measured pressure drop across a flow control element of the flow unit at a maximum open position, wherein the flow control element includes a variable position damper or valve in a flow path of an HVAC system;
• and
• determining a plurality of calibration values for relative pressure drops based on the calibration pressure drop at full open and a plurality of calibration measured pressure drops corresponding to a plurality of different calibration positions of the flow control element;
• and
• operating the controller of the flow unit, subsequent to calibrating the controller, comprising:
• detecting an operation measured pressure drop of the flow unit and an operation position of the flow control element;
• determining a dynamic nominal based on the operation measured pressure drop and a particular calibration value of the plurality of calibration values corresponding to the operation position of the flow control element;
• determining an operation relative flow based on a current measured flow and the dynamic nominal;
• determining a relative flow setpoint based on a current flow setpoint and the dynamic nominal;
• and
• controlling the operation position of the flow control element based the operation relative flow and relative flow setpoint by sending control signals to an actuator that physically adjusts the flow control element to regulate flow through the HVAC system.

A non-transitory computer readable medium including executable instructions which, when executed, causes at least one processor to manage a flow unit by:

• calibrating a controller of the flow unit comprising:
• establishing a calibration pressure drop at full open based on a measured pressure drop across a flow control element of the flow unit at a maximum open position, wherein the flow control element includes a variable position damper or valve in a flow path of an HVAC system;
• and
• determining a plurality of calibration values for relative pressure drops based on the calibration pressure drop at full open and a plurality of calibration measured pressure drops corresponding to a plurality of different calibration positions of the flow control element;
• and
• operating the controller of the flow unit, subsequent to calibrating the controller, comprising:
• detecting an operation measured pressure drop of the flow unit and an operation position of the flow control element;
• determining a dynamic nominal based on the operation measured pressure drop and a particular calibration value of the plurality of calibration values corresponding to the operation position of the flow control element;
• determining an operation relative flow based on a current measured flow and the dynamic nominal;
• determining a relative flow setpoint based on a current flow setpoint and the dynamic nominal;
• and
• controlling the operation position of the flow control element based the operation relative flow and relative flow setpoint by sending control signals to an actuator that physically adjusts the flow control element to regulate flow through the HVAC system.