Health monitoring methodology based on exergetic analysis for building mechanical systems

Exergetic analysis is not often performed in the context of retrocommissioning (RCX); this research provides insight into the benefits of incorporating this approach. Data collected from a previously developed RCX test for an air handling unit (AHU) on a college campus are used in an advanced thermodynamic analysis. The operating data is analyzed using the first and second laws and retrofit design solutions are recommended for improved system performance; the second law analysis is particularly helpful because it requires few additional calculations or data collections. The thermodynamic methodology is extended to a building's cooling plant, which uses a vapor compression refrigeration cycle (VCRC) chiller. Existing chiller data collected for the design of automated fault detection and diagnosis methodology is used. As with the AHU analysis, the second law analysis locates irreversibilities that would not be determined from a first law analysis alone. Plant data representing both normal and faulty operation is used to develop a chiller model for assessing performance and health monitoring. Data is analyzed to determine the viability of health monitoring by performing an exergy analysis on existing data. Conclusions are drawn about the usefulness of exergetic analysis for improving system operations of energy intensive building mechanical systems.