Mechanical Engineering Department
BS in Mechanical Engineering
The Cal Poly Heating Ventilation and Air Conditioning (HVAC) Department was donated a fume hood so that it could be used for educational purposes in the lab. The fume hood was not fully set up and only ran in a constant volume mode; the fan ran at full speed with no feedback to reduce air flow. A fume hood can be opened or closed using the sash; air flowing through the sash opening must always be above a certain speed. As the sash is closed the opening grows smaller and the speed of the air increases. Two additional modes of operation were designed that reduced the flow of air with the reduction of sash opening: a damper system that blocks the flow of excess air, and a variable frequency drive system that reduces the fan speed. These modes of operation are controlled with a PC with a software program called LabView. Students will be able to change the mode of operation and take data to see which mode of operation is the most energy efficient.