Fault diagnosis and energy consumption analysis for variable air volume air conditioning system: a case study

Several common faults and their causes in variable air volume (VAV) air conditioning system are presented, and the principle of fault diagnosis of air conditioning system is briefly described. The VAV air conditioning system was modeled in TRNSYS, and five typical faults of the cooling mode were simulated. The comparative analysis of the respective under normal operation and fault operation had been made, and the impact of each fault on the energy consumption was also analyzed. The actual operating characteristics of air conditioning system was then evaluated. Further, some parameters under fault operations were compared with those under the normal operation, from which the changing characteristics of parameters could be discovered, and the characteristics can be used to diagnose faults. The simulation results demonstrate that fault can affect the energy consumption of VAV air conditioning system, and the impact of each fault is different. In addition, monitoring the change of energy consumption and operation parameters is helpful in fault diagnosis, and the effective fault diagnosis has great significance to energy-saving of the air conditioning system.