Investigating thermostat sensor offset impacts on operating performance and thermal comfort of three different HVAC systems in Wuhan, China

Abstract

For heating, ventilation and air-conditioning systems (HVACs), their operating performance depends largely on sensors and their accurate measurements. Various types of faults are inevitable to sensors amounted in HVACs during the system lifespan, which eventually makes system deviated from the normal operation. To explore sensor fault impacts on different HVACs, the thermostat offset fault was taken as an example. For the same office building in Wuhan, this study compared its influences on operational performance of three HVACs including the ground source heat pump (GSHP) system, the variable refrigerant flow (VRF) system and the chiller + boiler (CB) system. The three HVACs were simulated simultaneously by EnergyPlus for the same target building with same outdoor meteorological environment to make a relatively fair comparison. The thermostat offset fault was introduced into the three HVACs with bias amplitudes ranging from −5–5 °C at the interval of 1 °C. Further, the fault impacts were quantitatively analyzed from three aspects in terms of system energy consumption, operating performance and indoor thermal comfort. Results indicated that the thermostat offset fault with different bias amplitudes and offset directions have different impacts on the three systems. Compared with the other two systems, GSHP is less affected by the introduced thermostat offset fault.

Keywords

• Heating
• Ventilation and air-conditioning systems (HVACs)
• Sensor offset
• Energy consumption
• Building operating performance
• Thermal comfort