Examination of the building recommissioning process inside variable air volume (VAV) systems with direct digital control (DDC)

This thesis has fulfilled a need within the building sciences (and HVAC community) for research concerning recommissioning of Variable-Air-Volume (VAV) systems equipped with Direct-Digital-Control (DDC). The results can be subdivided into two sections: the critical aspects (and longevity) involved with recommissioning, and the response of VAV airflow sensors. Field-testing indicated that the calibration of VAV airflow sensors within the DDC system was the most critical aspect of recommissioning. The longevity of recommissioning was determined to be greater than 21 months and unique analysis tools were developed to assist in the recommissioning procedure. Laboratory experiments were completed to determine a relative ranking of "poor" upstream duct conditions that are responsible for lowering the amplification and precision of VAV airflow sensors.