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 SWAMP
COOLER BLEED-OFF
Evaporative or "swamp" coolers use fans to move hot,
dry air through wetted pads and into homes. An efficient swamp
cooler operating in low humidity can cool air by 20 to 25OF
(11 to 13OC). As
water evaporates from the pads, dissolved salts and minerals
are left behind. This concentration eventually causes scale
to precipitate out on the pads, making them hard and non-absorbent.
To prevent this, concentrated salts are
removed from swamp coolers via some sort of "bleed-off"
mechanism. In some cases, a continual stream of water is removed;
in other cases, a manual valve is opened occasionally to drain
water out of the cooler. Newer models have timers which dump
the contents of the water pan after a set number of hours
of operation.
This bleed-off water can be put to
some uses, despite its elevated salinity and hardness. The
water can either be diverted directly to salt-tolerant species
such as turf, or stored for later use. If stored, the water
can be diluted with tap water or rainwater, thereby reducing
its salinity.
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