On the outside cover of the PuriFresh ERV, two of the four openings have stale air leaving the unit and the other two have fresh air entering. Since the openings are closely spaced, why doesnt the stale air leaving get sucked back in and contaminate the fresh air entering?
The Bernoulli effect keeps stale air from leaving the stream close to the unit and contaminating the fresh air entering. When a jet of air leaves a port, close to the port, the Bernoulli effect causes air around the jet to enter the jet. It is only further out that the jet breaks up causing the air in the jet to disperse and enter the surrounding air.
