Premier Cooling Media is a generic term for high efficiency fluted evaporative cooling media. This media is manufactured by several manufacturers in the United States, China, India and Mexico among others. The most common configuration of this type media is a 45 /15 degree transverse flute arrangement for typical evaporative cooling applications.
This media is a cellulose material impregnated with insoluble anti-rot salts and rigidifying saturants. The media incorporates an internal geometry of transverse 45 degree and 15 degree alternating flutes. The 45 degree flute carries the water to the face (intake) side of the media while the 15 degree flute is aligned with the direction of air flow.
This flute arrangement is self-cleaning and increases cooling efficiency by causing air turbulence while air is traveling through the media. This media provides approximately 123 square feet of evaporative surface area per cubic foot of media. Efficiency of this media is about 90% at 400 to 500 feet per minute face velocity in 12" depth. Life expectancy is dependent upon many factors but is usually 3 to 5 years when properly maintained and water pH is between 6 and 8.
Cooling efficiency is based on "saturation efficiency" (ability to transfer water vapor into the air stream). The two major factors to be considered in determining the efficiency of the media are media thickness and air flow face velocity . The following table defines the saturation efficiency by media thickness and face velocity. Efficiency & Pressure Drop Data is based on typical performance information as published by certain manufacturers for their 45/15 rigid cooling media and is approximate.
| Face Velocity | Percent Media Efficiency at Media Depth: | Static Pressure Drop at Media Depth: | ||||||||||
| 4" | 6" | 8" | 12" | 16" | 24" | 4" | 6" | 8" | 12" | 16" | 24" | |
| 200 FPM | 71% | 86% | 91% | 96% | 99% | 99% | 0.02" | 0.03" | 0.04" | 0.06" | 0.08" | 0.09" |
| 300 FPM | 67% | 81% | 88% | 94% | 98% | 99% | 0.03" | 0.05" | 0.07" | 0.10" | 0.13" | 0.19" |
| 400 FPM | 62% | 77% | 84% | 92% | 96% | 99% | 0.05" | 0.09" | 0.11" | 0.18" | 0.25" | 0.31" |
| 500 FPM | 59% | 72% | 82% | 89% | 94% | 99% | 0.09" | 0.12" | 0.17" | 0.26" | 0.36" | 0.50" |
| 600 FPM | 57% | 70% | 80% | 88% | 92% | 99% | 0.12" | 0.18" | 0.22" | 0.36" | ||
Note: Face velocities higher than 600 FPM are not recommended. Contact Premier Industries, Inc., for information regarding methods available to handle higher velocities. Example: At air velocity of 500 FPM and media thickness of 12", the saturation efficiency will be 90%. Recommended design velocity is 500 - 550 feet per minute. This is the best trade-off between performance and cost.
Percent efficiency defined:
It is necessary to know the dry bulb temperature and wet bulb temperature entering the media to be able to apply the percent efficiency. The difference between the dry bulb and wet bulb is know as the "wet bulb depression". The wet bulb is the lowest point the dry bulb temperature can be dropped across the media. The percent of the wet bulb depression will equal predicted discharge temperature. I.E. at 100 degree dry bulb and 70 degree wet bulb, the wet bulb depression is 30 degrees (f). To determine expected dry bulb temperature drop across the media, multiply 30 (wet bulb depression) X .90 (90%). Temperature drop across the media is 27 degrees (f). To determine expected dry bulb discharge temperature, subtract the temperature drop from the entering dry bulb temperature. I.E. 100 - 27 = 73 degree (f) discharge temperature. Refer to "Formulas" section for this and additional information.
The following formulas are provided primarily to determine evaporation rate of water from the media into the air stream. The evaporation rate is necessary to calculate water usage, bleed-off rate and total flow rate of water over the media. The evaporation rate changes with the climate and air flow changes. If desired, the setting of water flow over the media and bleed-off rates can be adjusted based on the evaporation rate.
Media efficiency: The first step to determine other data is to establish the actual media efficiency. Efficiency = (T1 - T2) / (T1 - Tw) X 100 Where T1 = entering dry bulb temperature, T2 = leaving dry bulb temperature and Tw = entering wet bulb temperature.
Discharge Temperature: To determine predicted discharge temperature use the following formula. (% efficiency X (Dry Bulb - Wet Bulb)) = Discharge Temperature.
Air Velocity: in feet per minute (FPM) Feet per minute (FPM) = Cubic feet per minute (CFM) / Square feet of face area (open to air flow).
Water evaporation rate: in gallons of water per hour (GPH). = (CFM x (entering Dry Bulb - leaving Dry Bulb)) / 8700
Bleed-off rate = Evaporation rate x .20 (20%) (approx) = bleed-off rate. Note: divide by 60 for gallons per minute.
Water flow rate: in gallons of water per hour (GPH). Evaporation rate + bleed-off rate X 3 = water flow rate in GPH. Note: divide by 60 for gallons per minute.
The media must be installed in a proper orientation to the air flow. The 45 degree flute must be aligned upwards in the direction of the air flow (intake side of the flute must be lower than the discharge side) and the 15 degree flute must be aligned downwards with the air flow (intake side of the flute must be higher than the discharge side). If the media is aligned improperly, the water will flow to the discharge side of the media and can be easily entrained in the air flow.
The media is available in depths up to 24" as required. Premier maintains large inventories of this media in 24" depths and will cut to size and ship next day in the great majority of cases. Height (length) is restricted to 72" standard, however Premier can supply up to 78" lengths. Standard width is 12", however Premier can cut to smaller width if desired. Media is usually shipped in individual "sticks" (pieces) to include sufficient number to provide the total width of the unit into which the media is to be installed.
Refer to our home page for additional sections of technical data such as installation, removal and replacement, cooling season start up, winter shut down, water chemistry and others.
