PRELIMINARY ASSESSMENT OF IMPACT OF TYPICAL FAULTS ON ENERGY PERFORMANCE OF AIR-HANDLING UNITS BY MEANS OF A DYNAMIC SIMULATION MODEL: A CASE STUDY

A widespread adoption of predictive maintenance procedures using automated Fault Detection and Diagnostics (FDD) methods could be used to reduce the energy waste of poorly maintained and/or improperly controlled Air-Handling Units (AHUs). A detailed dynamic simulation model of the AHU (nominal cooling/heating capacity of 5.0 kW) serving the SENS-i Lab of the Department of Architecture and Industrial Design of the University of Campania Luigi Vanvitelli (Italy) has been developed, calibrated and validated based on several experimental tests by means of the dynamic simulation software TRNSYS. In this paper, the model has been used to analyze the performance of the AHU while serving a typical Italian building office. In greater detail, the simulations have been carried out with and without the occurrence of typical faults of AHUs, such as the positive and negative offsets of both room temperature sensor and relative humidity sensor. The results allowed to investigate the dynamic variations of key-parameters associated to fault operation, identify simplified rules for detection of any non-optimal states of HVAC and implementation of effective FDD procedures, evaluate the impact of faults on thermo-hygrometric comfort conditions and electric energy consumption, assess the potential energy and economic benefits of automated FDD methods.