RE: NANFA-- RE: now airlifts; splitting hairs

Nick Zarlinga (njz_at_clevelandmetroparks.com)
Thu, 10 Jul 2003 16:26:33 -0400

I need a little more than just your past experience to prove your efficiency
threory. The debate doesn't revolve around sucking water, the debate is all
about how energy is converted to ultimately move water. As we know,
electricity is used to move an impeller which has to move a very dense
medium. An air pump uses the electricity to compress air (which in itself
has varying degrees but for hobbyist sake, we are not creating a very high
psi) and force it into the dense watery medium ( and this depends on the
depth that it is injected but again, we are talking normal home tanks). The
electricity is not being used to move the water at all in this case. The
"negative space" in the airlift is being filled by the water which in turn
causes the water movement. I have to beleive that compressing air (in the
manner that our average air pumps do) is much "easier" to do than making
water move, simply because of the density of air vs water. I do not have
numbers to spout off but Spotte covers all of this in his books and even
allows you to figure out how much water your airlift can move. The next
step would be to figure out how much energy the air pump uses vs the
powerhead of simliar flow. As Todd said, we are not talking about velocity,
but water movement. Air lifts are horrible for a pressure situation. Now
again, we are talking about the most efficiently designed air lifts which
most of us do not have in our aquariums, so this debate may be moot with
regards to the efficiency question, however there are many other reasons why
air lifts are better than pumps for basic aspects of circulation.

Other benefits: one pump to run several aquariums without cross
contaminating, doesn't add heat to the tank, doesn't crowd out your
electrical outlets; insert others here.

But as we all know, go with what works for you.

Nick Zarlinga
Aquarium Biologist
Cleveland Metroparks Zoo
216.661.6500 ext 4485

-----Original Message-----
From: owner-nanfa_at_aquaria.net On Behalf
Of Moontanman_at_aol.com
Sent: Wednesday, July 09, 2003 9:00 PM
To: nanfa_at_aquaria.net
Subject: Re: NANFA-- RE: now airlifts; splitting hairs

In a message dated 7/9/03 5:57:23 PM Eastern Daylight Time,
njz_at_clevelandmetroparks.com writes:

>
> prove it
>
Powerheads are more direct, making pressurized air uses more energy than any
other type of power. One of those things I learned while working for DuPont.
Air power is more versatile to use than direct power but more expensive in
energy used to make than any other energy source. Powerheads turn
electricity
directly into suction but air pumps must use electricity to make pressurized
air
then the air is used to make suction, Just not as efficient but pressurized
air
is more convenient. Which is more important?

Moon

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