The operation of the VFDs on the heating and cooling systems is based on flow through the control valves. Costa knew from experience that Belimo's characterized control valves (CCVs) were extremely accurate and they, along with direct connected actuators and a DDC system, would enable the university to continuously monitor every valve in the building and adjust pump flow rates based on valve position. Minimum required flow rate is attained when all zones are satisfied and no control valve is more than 90% open. Costa Engineers was determined to make every horsepower count.
This accuracy, said Tony Costa, is a function of two characteristics, both of which result in a linear heat output. First, actuators for the CCVs are direct-coupled, eliminating typical mechanical linkage, which may, over time, impede the repeatability of the valve.