1. Common Active Noise Cancellation Applications
Noise Cancellation in Automobiles
Noise Cancelling Headphones

2. What about HVAC applications?
Can Active Noise Cancellation techniques be applied to HVAC applications?
Noise can come from multiple locations

3. ANC Concepts Feed-forward ANC Feed-back ANC Hybrid ANC
Through research - can determine which concept is the most effective & easiest to develop for this application
Hybrid ANC
Feed-back ANC with residual error microphone

4. Applications – where & why is this needed?
Hotel ‘Ptech’ units
Classroom units
Exterior equipment
Building retrofit - more efficient equipment into existing space
Hotel unit – I never get a good night sleep because I am either disrupted by Ptech noise or if I turn unit off – I am too hot/cold. Anniversary trip when hallway ahu had radiated noise through the wall & we couldn’t sleep + elevator noise.
Classroom – Lakin project w/ UVs in each room. We maintained acceptable ASHRAE noise criteria but students sitting close to the unit still experience a disturbingly high level of noise (effects learning & requires teachers to speak louder for those students)
Exterior – anyone ever experienced a noisy air conditioner?
Mechanical / boier rooms – equipment designers are getting much better at reducing noise but often these rooms are so loud you can’t even hold a conversation
Retrofits – often updating to more modern HVAC systems requires obtaining equipment that doesn’t fit neatly into existing building architecture, so noise generating equipment often needs to be installed near occupied areas & higher occupant noise levels are experienced at the benefit of energy savings.
Mechanical / Boiler Rooms

5. Goals
min. 10dB noise reduction from 20 Hz to 20 kHz
easy to set up / calibrate (if necessary)
‘Function over Form’ Prototype - no size restriction
Battery powered or 120 VAC powered