Field testing of advanced ventilation controls for variable air volume systems

Abstract

Results from the experimental phase of a larger research project are presented for three promising ventilation controls capable of meeting the ventilation requirements of ANSI/ASHRAE Standard 62-1989 (ASHRAE 1989) with low energy use. Each control dynamically adjusted the outdoor air (OA) requirement based upon occupancy and measured building zone loads. Credit for unvitiated air from over-ventilated spaces was also taken in each control. Controls 2 and 3 used primary airflow rate as an optimization variable to decrease the required OA flow rate, thus reducing the energy needed to condition OA. The supply air temperature in control 2 was a constant, but was an additional optimization variable in control 3. The three ventilation controls were achieved by the simulation/optimization algorithms resident in a stand-alone personal computer (PC) on site. A total of 24 days of performance data were collected. Typical day data sets for each control are presented in some detail. The objective of the experimental phase was to verify the reliability of the simulation/optimization algorithms resident in the on-site PC. That objective was met for each of the three controls since excellent agreement was found between the measured data and the control algorithm predictions.