Systems and methods for characterizing variable-air-volume (VAV) valves for use in HVAC systems

A computer readable medium having stored thereon in a non-transitory state a program code for use by a computing system, the program code causing the computing system to execute a method for characterizing a VAV valve that has a valve member that is actuatable to control an airflow through the VAV valve, comprising:

• storing a generic characterization for the VAV valve that generically characterizes a position of the valve member versus the airflow through the VAV Valve;
• receiving a measure of airflow at each of one or more positions of the valve member;
• applying a logarithmic function to the measure of airflow at each of the one or more positions of the valve member, resulting in a logarithmic expression of the measure of airflow at each of the one or more positions of the valve member;
• applying the logarithmic function to the generic characterization of the VAV valve at each of the one or more positions of the valve member, resulting in a logarithmic expression of the generic characterization of the VAV valve at each of the one or more positions of the valve member;
• comparing the logarithmic expression of the measure of airflow at each of the one or more positions of the valve member with the logarithmic expression of the generic characterization of the VAV valve at each of the one or more positions of the valve member;
• determining a custom characterization for the VAV valve based at least in part on the comparison;
• and
• downloading the custom characterization to the VAV valve for subsequent use during operation of the VAV valve, wherein during subsequent use, the VAV valve references the custom characterization to identify a commanded position of the VAV Valve that achieves a commanded airflow through the VAV valve, and controls an actuator of the VAV Valve to move the VAV Valve to the commanded position.

A system for characterizing a VAV valve that is configured to move a position of a valve member between a first open position and a second open position to control an airflow through the VAV valve, the system comprising:

• a memory for storing a generic characterization for the VAV valve that generically characterizes the position of the valve member versus the airflow through the VAV valve between the first open position and the second open position of the VAV valve;
• an airflow measuring device for measuring the airflow through the VAV valve;
• a controller operatively coupled to the memory and the airflow measuring device, the controller configured to:
• receive a measure of airflow from the airflow measuring device at each of one or more positions of the valve member;
• compare the received measure of airflow at each of the one or more positions of the valve member with the generic characterization of the VAV valve stored in the memory;
• determine a custom characterization for the VAV valve based on the comparison and the generic characterization of the VAV valve;
• and
• download the custom characterization to the VAV valve for subsequent use during operation of the VAV valve, wherein during subsequent use, the VAV valve references the custom characterization to identify a commanded position of the valve member that achieves a commanded airflow through the VAV valve, and controls an actuator of the VAV Valve to move the position of the valve member to the commanded position;
• wherein the VAV valve has an approved operational airflow range extending between a first airflow and a second airflow, and wherein at least one of the one or more positions of the valve member that the measured airflow is received corresponds to a position of the valve member that results an airflow that is above a mid-point between the first airflow and the second airflow of the approved operational airflow range, and wherein the one or more positions of the valve member at which a measure of airflow is received comprises less than four positions of the valve member.