A novel constant-air-volume range hood for high-rise residential buildings with central shaft

摘要

This study proposed a control logic for a novel constant-air-volume (CAV) range hood. The Field Oriented Control vector was used to adjust the fan speed by comparing the current exhaust volume to the desired value. Experiments were conducted to test the air volume retention ability of the developed constant-air volume range hood. Test results show that within a certain range of fan static pressure, the exhaust air volumes of the constant-air-volume range hood can remain constant. To verify the operation performance of such constant-air-volume range hood in a real central exhaust shaft, the performance curves of the fan obtained from the experiments were substituted into the our previously developed ductwork hydraulic model to calculate the distribution of the exhaust air volume under varied fan curves and shaft coincidence factors. Modeling results indicate that in a central exhaust shaft, the CAV range hood can meet user's varied exhaust demand at low coincidence factor (e.g., 0.2) but its capability to maintain constant exhaust air volume decreases when the coincidence factor of the central shaft is high (0.4 or 0.6). A staged multi-gear control method was also proposed to address the fan noise concern and static pressure limitation. The fan can automatically switch to a lower exhaust gear when it reaches the threshold of the rotating speed.(c) 2021 Elsevier B.V. All rights reserved.