Whether or Not To Install Evaporative Cooling
if your cooler is not performing well)
Refrigerated Air Conditioning??
common question asked by many is
"should I install an Evaporative Cooler or
Refrgerated Air Conditioning?"
note: The correct terminology is "Evaporative
Cooler" and NOT "Swamp Cooler")
you live in a coastal or tropical region, you
probably never hear the expanation below because
"evap cooling" is not very efficient
when your ambient air is full of humidity.
(except for use in greenhouses
where high humidity is healthy for the plants)
If your wet bulb temperature is around 60%
and higher, then refrigerated cooling is the correct
In lower wet bulb regions a properly sized evaporative
cooler can be a very cost- effective and comfortable
the evaporative cooler is the key
A good "rule
of thumb" is to have 1 air
change every 3 minutes in northern states,
1 air change every 2 minutes in the mid
section and 1 air change every 1-2 minutes
in the southern states.
The Rule of Thumb
formula for sizing your cooler is very simple;
the length by the width by the height
of the area to be cooled to get the cubic footage
for the area. Then divide by your air change factor
minutes. The example below reflects a "2"
minute air change.
home that is 30' wide, 40' long and 8' ceiling
has a total of 9600 cubic feet of area to
be cooled. 30 x 40 x 8 = 9600
the factor two (for an air change every
divide 9600 by two to give you the CFM required,
in this case 4800 CFM. 9600 / 2 = 4800
this case you would want to use a 4800 CFM
(Note: It never hurts to go one size
up. You might consider a 5500 CFM cooler
The cooler can be run on low speed, then
cranked up to High on severe days.
Another important factor is "Exhaust
Air'. A good cooler design is to exhaust slightly
more air than your cooler is supplying, this can
be done with windows or doors being open slightly
or a sized exhaust fan inter-locked with the cooler.
enough air exhausted is important so that there
is negative air pressure in the conditioned space,
positive air will cut down your blowers capacity.
A big advantage to evap coolers is that the capacity
can be changed easily by adjustable pulleys to
increase or de-crease air flow. If you open your
front door and the pressure slams it shut then,
you need more exhaust openings, such as a window
or another door.
air exhuasted also reduces the humidity build
air conditioning cools no matter what the humidity
is and usually increases your home value (as
well as your electric bill) more than an evap
cooler, but with a well designed evapaporative
cooling system installed, cost is less to install
and hardly noticeable on your utility bill.
A few notes for evaporative cooler maintenance:
more frequent aspen cooler pads are changed the
better - don't try to get 2-3 years out of pads.
Twice a season is best (although seldom done).
Be sure to change aspen pads at the beginning
of each season when starting up your cooler.
exception to this is using a cooler with a celdek
type pad, such as our UltraCool)
The pads can easily be used for five years or
more, when the cooler is properly installed with
a bleed off system.
properly installed bleed off system can prolong
the life of your pads and greatly reduce the corrosion
affects on your cooler. Below are two types that
can be used.
the motor and bearings - Most evaporative cooler
motors do have oil ports. Use SAE #20 non-detergent
Do not use motor oil. It has detergent content.
This will reduce the life of your bearings.
for proper belt tension, and amp draw. (Overloading
the amp draw will burn the motor out)
(just a few tips - there are many more things
to check out)
This should be done by a
with larger cooler
or dirty filters
with new pads
pads or lack of water while cooler is operating
water distributing system for possible obstruction
in tubing. Check pump operation.
air discharge openings or inadequate exhaust
from area being cooled, causing humidity
building up and discomfort
coolers must have large enough
Ductwork sized for refrigeration simply
will not let the higher cfm from a cooler
sure there is adequate provision for exhausting
air from area being cooled.
(See also item above re: inadequate exhaust)
some areas, there may be a few days during
the summer when the relative humidity is
high, resulting in poor cooling. (60% or
higher) These are limitations of an evaporative
cooler under conditions of high wet bulb
motor for correct direction.
and reinstall blower wheel to turn in correct
running too slow
motor amps. If below name plate amperage,
readjust variable pitch motor pulley to
increase blower speed. Do not increase amperage
above motor rating. This will burn the motor