Investigation on the performance of the chilled water system with the key sensor fault

Abstract

Sensors for the role of control ensure the HVAC system operates reliably and optimally. Among them, the readings of some sensors are the key for the whole system since they are the representation of the controlled objects, such as the chilled water outlet temperature, or the room temperature and so on. Unfortunately, sensor fault is unavoidable due to the system error. The system will be misled to the unexpected or even very severe situation by the controller which got the erroneous input. In this paper, a real building model, which was developed in the simulation environment of the EnergyPlus and its external interface, BCVTB, was employed to investigate the performance under the key sensor fault condition. The chilled water outlet temperature sensor, which is in the supply side of the chilled water loop, and the room temperature sensors, which are in the demand side, were introduced different bias fault from negative levels to the positive levels to reveal the performance changing. Results show that the variation of energy consumption with the sensor fault in the demand side is higher than that in the supply side. Some performance parameters, such as COP of the chiller, and the SCOP of the plant, are quite different, while the indoor thermal comfort is stable under the chilled water outlet temperature sensor fault but different under the fault of the room temperature sensors. This simulation model will be combined with the strategy of the sensor fault detection, diagnosis and reconstruction to accomplish the fault-tolerant control in the future.