In the ASHRAE fitting database, there are negative duct fitting coefficients. I assume this means that that particular fitting will produce a pressure regain. However, I am unsure that it would be a static regain because:(adsbygoogle = window.adsbygoogle || []).push({});

the formula is P(total)=C*P(velocity), and P(total) only can only drop as it travels thru a duct (downstream of the fan). Is this a contradition?

So I am confused of what the negative means because of this contradiction. Anybody know?

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# Negative duct fitting coeffecient

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