A metrological analysis of a (Direct Digital Control) DDC-based air conditioning system

Although (Direct Digital Control) DDC-based air conditioning systems can po tentially carry out efficiency checks, the instrumentation installed in the se systems is not always suitable for making reliable plant status estimati ons. In order to verify the metrological performances of these systems and to define how reliable measurements can be made the authors set up a small- sized HVAC (Heating Ventilating and Air Conditioning) system provided with standard HVAC type sensors. The measurement instrumentation was verified by means of calibration and field tests, and the operating conditions in whic h it is possible to estimate in a sufficiently reliable manner the performa nces of each system component using the same instrumentation were determine d experimentally. This analysis has shown that the normally used sensors ar e often highly dependent on operating and installation conditions and, cons equently, the efficiency estimation of each component is very unreliable us ing uncalibrated sensors. (C) 1999 Elsevier Science S.A. All rights reserve d.