Abstract

An air conditioning system economizer, investigated in this thesis, consisted of three dampers, an outdoor air, a recirculation, and a discharge damper. The purpose of an economizer is to control the ratio of the outdoor air flow rate to the recirculation air flow rate. The dampers were opposed blade type and had equal sizes. They were coupled through a control system. Two control strategies were investigated. In the first strategy, the three economizer dampers were coupled so that the outdoor air and discharge damper open as the recirculation damper closes. In a second strategy, the discharge damper was always open during operation and the outdoor air and recirculation dampers were coupled so that the outdoor air damper opens as the recirculation damper closes. The two coupled dampers control strategy will require slightly less power than three coupled damper strategy. The study showed that the linearization of throat area versus control signal is the most important factor for reducing power, whether the three coupled it is or two coupled dampers control strategy is used. linearization provides good control of the air flow rates, from 0% to 95%. (Abstract shortened by UMI.)