Abstract

Ongoing commissioning of commercial and institutional buildings relies on the available trend data from a building automation systems (BAS) to be able to monitor the buildings energy performance using developed tools. However, it is often that the BAS has no information of the chilled and condenser water flow rates that pass through the evaporator and condenser, respectively, of a chiller.
This thesis proposes a virtual flow meter (VFM) to estimate the chilled and condenser water mass flow rates. The virtual flow meter uses a thermodynamic analysis of a chiller under six different scenarios of available sensors from a BAS with some manufacturer data to fill the gaps left by the missing sensors.
This thesis presents the use of the VFM in three case studies to estimate the chilled and condenser water mass flow rates. The evaluation of the accuracy of the VFM model is performed using an uncertainty analysis, statistical indices (CV-RMSE, NMBE) and a paired difference statistical hypothesis test to provide insight into the limits of CV-RMSE and NMBE that determine an acceptable model. Then, the estimates from the VFM are used to estimate the virtual coefficient of performance of the chiller and the cooling plant for use with developed ongoing commissioning methods of cooling plants.
This thesis presents the development of a graphical user interface for the VFM model and the sensitivity of the virtual flow meter to it inputs is discussed to aid the user in achieving accurate results.