Anyone have experience or input on the indirect evaporative coolers as a cooling alternative?
http://www.nbnnews.com/NBN/issues/2007-08-13/Research/index.html
Indirect, or two-stage evaporative coolers do not add humidity to
the air, but they cost more than direct coolers and operate less
efficiently.
Two-stage evaporative coolers combine indirect with direct
evaporative cooling by passing air inside a heat exchanger that is
cooled by evaporation on the outside. In the second stage, the
pre-cooled air passes through a water-soaked pad and picks up humidity
as it cools.
Because the air supply to the second stage evaporator is pre-cooled,
less humidity is added to the air, whose affinity for moisture is
directly related to temperature. The result, according to the
manufacturer, is cool air with a relative humidity between 50% and 70%,
depending on the regional climate. A traditional system would produce
about 80% relative humidity.
Among the attributes of evaporative coolers cited by PATH:
- Direct coolers cost about $700 to $1,000 installed, compared to
several thousand dollars for conventional air conditioning and
ductwork. In addition, their operating costs are about one-third those
of conventional air conditioning — including the cost of water,
depending on electric and water costs. Indirect evaporative coolers are
much costlier.
- Evaporative coolers use about one-fourth the electricity of conventional air conditioners.
- Evaporative coolers can improve a home’s indoor air quality by
drawing a large supply of fresh outdoor air through the home. However,
they consume between 3.5 and 10.5 gallons of water per hour of
operation.