CH-12-018 -- Modeling the Performance of ECM and SCR Parallel Fan-Powered Terminal Units in Single-Duct VAV Systems PDF

Single duct variable air volume systems often use series and parallel fan powered terminal units to control the air flow in conditioned spaces. A laboratory verified model of single duct variable air volume systems was developed that used series and parallel fan terminal units where the fan speeds were controlled by either silicon controlled rectifiers or electronically commutated motors.

The single duct variable air volume simulation results showed that there was no significant difference between the annual energy used by parallel systems with silicon controlled rectifier controlled motors when they were compared to parallel systems that used electronically commutated motors. The study included the simulation of the operation of the same facility at five weather locations around the United States.