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re: fan air, don't pump water heat exchanger
25 oct 2000
toby wrote:
>if you want to make a water to air heat exchanger by coiling 100' of
>1/2 dia. irrigation tubing into a 55gal drum, what is the air speed in
>the tube when an $11, 12v, 2.3w, 32 cfm@0"h20pressure and 0cfm@3.4"h20,
>computer fan blows air through it?
i doubt that little fan can lift 3.4" of h20 at 0 cfm, in light of similar
rotron and grainger fans pooping out at 0.15" and 0.5". before you believe
it will (or worse, post your beliefs as factual), you might a) recheck the
numbers with the original source, b) get a copy of the fan curve (pressure
vs airflow), and c) buy one and mount it on the side of a sealed cardboard
box with a ruler and a u-tube manometer made from some 1/4" plastic tubing
taped to the outside.
>the air speed is not found by this equation: v = cfm /a
>i.e. velocity = cubic feet per minute / tube cross-sectional area
hogwash.
>may jesus bless,
may he give you a clue :-)
nick
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