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re: (almost) free air conditioning.
20 jul 2001
dave gower wrote:
>...i have a two-speed commercial grade fan which can pull 1100 cfm...
>efficiency? wow. it draws 4 amps, or 440 watts. i measured the temperature
>of the incoming and outgoing air. the temp rise was 4 degrees c. at 1100 cfm
>if my math is correct that's 85000 btu/hr.
one cfm of airflow with a 1 f temp diff moves about 1 btu/h, so it sounds
like you are moving 4x1.8x1100 = 7920 btu/h of heat with 440x3.41 = 1500
btu/h of electricity, for a 7920/1500 = 5.3 cop, more than a typical ac
with a cop of 3...
grainger sells 86 w 48" ceiling fans that move 21k btu/h...
nick
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