Sizing Instructions - AdobeAir ArticCircle ED143 Specifications

Sizing Instructions

For Commercial/Industrial Environments
The four steps (using ASHRAE 5% design standards for climatic
conditions) to determine the correct CFM requirements are
1. Determine the temperature of cooler discharge (Cd)
Cd = WB + .2 (DB - WB), where WB = ambient wet bulb temperature
in F and DB = ambient dry bulb temperature in F
2. Determine the design sensible heat load (SHL) in (BTU/h) (Note A)
3. Compute needed CFM from the formula
CFM = SHL 1.08 t
Where CFM = Cubic feet per minute of cooler discharge,
SHL = British Thermal Units per hour, sensible load.
and t = Difference between temperature of air leaving the conditioned
environment and entering the conditioned environment (cooler
discharge) or temperature rise (See Note B)
4. From the Air Delivery sections in the charts select the equipment
that will deliver the required CFM at the expected system static
pressure.
Note A: Sensible load only of conditioned environment
Note B: t is a designer-specified number. Average room temperature
will be approximately midpoint between two values expressed.
Alternative Sizing Method
If heat load is undetermined this method may be used, it assumes
commercial/light industrial environment with normal heat loads.
Unusual heat loads may increase these requirements, and should
be calculated by the other method.
1. Determine Cd as in (1) of other method
2. Determine the volume of the area to be cooled
In work spaces with high ceilings consider only the worker environment
– normally up to 8 or 10 feet above the floor. If large volumes of space
are occupied by machinery or stored goods these volumes need not be
included.
3. Determine required CFM
Multiply the volume in cubic feet (from step 2) by the appropriate factor
depending on Cd:
Factor
if Cd F less than 69.7
69.7 -72 .25
72 -73.6 .32
73.6 -75
75 -76.3
76.3 -77.5
Over 77.5 1.0+
4. From the air delivery sections of the charts, select the equipment
that will deliver the required CFM at the expected system static
pressure.
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Motor Sheave Selection
1. Determine the external static pressure
of the air delivery system.
2. Determine the motor (H.P., Voltage and Phase) required to deliver
the design airflow.
3. Determine the shaft size for the motor selected.
Refer to the Electrical Specifications chart on page 7.
4. Determine the RPM that will deliver the required airflow (CFM) at
the static pressure of the system.
Refer to the Certified Air Delivery CFM chart for the chosen cooler,
find the selected motor HP.
5. Determine the sheave, and the number of turns open, that is
closest to the desired RPM.
Refer to the Sheave Selection charts on page 6. Find the selected motor
HP, shaft size, and desired RPM (See Steps 2-4 above). You might need
to look at more than one sheave before finding the correct RPM.
6. Specify the sheave and sheave setting
(turns open) for the installer.
Ordering
When ordering your cooler, you should know this information.
System design static pressure.
Desired air volume at system design.
Electrical power supply available.
Stability of structure to support operating weight of unit.
Complete systems consist of the following components, and are
sold separately for application versatility.
Cabinet
Motor
Motor sheave
Pulley-belt kit
Pump
NOTE: Motor starters, internal wiring and over-current protection are not supplied.
KoolKalk...
Computer Aided Sizing
The sizing method described in this brochure can be used for general
sizing of direct evaporative coolers.
For more accurate sizing we recommend the use of KoolKalk... an IBM
compatible computer program designed specifically for AdobeAir
Evaporative Coolers. Contact your local AdobeAir representative for
more information.
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