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re: evaporative coolers question
9 jul 2001
sacquebouche wrote:
>i am trying to locate a portable evaporative cooler for upstairs...
perhaps you need a damp hat (tm), a sombrero woven from soaker hose
with a small pump that increases the water pressure whenever the rh
under the hat drops to 60% (an upper level for human comfort.) this
might also exist in backpack or cummerbund form.
this could reduce the air temp around your body from 105.9 (july max
in phoenix, with w = 0.0105) to a "60% damp bulb temp," td (r), where
100(0.6exp(17.863-9621/td)-29.921/(1+0.62198/w)) = 105.9+460-td, using
bowen's equation and a clausius-clapeyron approximation for water vapor
pressure in air, ie td = 9621/(21.96-ln(615.6-td)) = 543.9 r or 84 f,
after a few iterations.
h&r (800) 848-8001 sells $4.95 navy surplus hair element humidistats
in 1x2x5" fine brass boxes full of holes, with a 20-80% range and 3-6%
differential and an spdt 7.5 a 125 vac microswitch that can be wired to
open or close on rising humidity. their catalog number is tm89hvc5203.
their $3.75 tm89pmp5655 3-6vdc pump can deliver 8 oz per minute with
a 20' head.
humans lose 40% of their heat by convection, 40% by radiation, and
20% by evaporation. conduction seems vastly underutilized. where are
the heat sink hats and copper bead chair cushions and water-filled
air-chairs and chain mail vests worn under shirts?
nick
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