VA-89-13-1 -- Observed Performance of VAV Hood Controls PDF

A series of performance tests were developed estabfish a performance record for VAV fume hood controls installed at a major research university over fouryears. The tests were conducted in operating facilities and quantify the control system’s response time, stability, and ability to control face velocity at various sash positions. Room pressurization was also observed. Thirty-six hoods, fitted with a variety of types and manufactures of developed a progressive VAV ventilation standard for VAV controls, were tested. Seven of these were found to be operating as constant-volume hoods and minor deficiencies were found in six others. For operating systems, average response time was 13 seconds in hoods with through-the-wall sensors and 4 seconds in systems using sash position sensors. A program is described that operators of research facilities can use to periodically performance, monitor user-controlled parameters such as hood diversity, and compile results in a data base. Industry needs for VAVlab systems are discussed.