|
Everyone has experienced natural evaporative cooling, although few
are aware of it. When a person steps, dripping wet, from the shower
or swimming pool, evaporative cooling makes him or her feel cold, even
though the air may be warm. At the lakeside or seashore, it is evaporation
from the water surface that makes the breeze refreshingly cool.
In a forest or green field, the air is freshened and cooled by evaporation
of moisture from plant and tree leaves. The human body itself is
cooled primarily by the evaporation of perspiration.
Evaporative cooling is undoubtedly man's oldest method of finding comfort in hot climates. Ancient records reveal that wetted grass mats and porous jars were used to cool air or water by the evaporative process.
Whenever water is evaporated (i.e., is converted into water vapor), heat is absorbed. Wet the back of your hand; then blow on it. The skin surface is immediately cooled. You have just demonstrated the basic principle of evaporative cooling.
The primary cooler components-evaporative media, blower and electric motor-are housed in a sturdy cabinet of stainless steel, with provisions for efficient water distribution to the media and a discharge outlet for the cooled air. The evaporative cooler is an essentially simple and trouble-free mechanism. However, the efficiency, dependability and performance of the cooler depend on hundreds of details of design and workmanship.
Some of the design factors involved in the production of each FreeCool ™ System which will give many years of customer satisfaction are: the amount of media area; the type and density of the media; the type of media holders; the design of the blower and its housing; the desired air velocity; design of the water distribution system; selection of appropriate materials, such as steels and coppers; finishing of the exposed metal parts to protect them from corrosion; design of water recirculating pumps, and selection of electric motors with the proper characteristics.
Of equal importance are effective testing procedures and manufacturing know-how. Frees, Inc. has sharpened its engineering and manufacturing skills across more than three decades of leadership in the air cooling and heating fields. Every FreeCool ™ evaporative cooler has been designed for the utmost efficiency in performance and is constructed to the highest standards of quality.
Why Evaporative Air Cooling Creates Comfort
- Lowers actual temperature. Properly installed, the cooler provides a continuous flow of cool air that lowers actual room air temperature.
- Lowers effective temperature. Rapid motion of the cool air increases skin surface evaporation. This results in body heat loss and lowers effective temperature (temperature people actually feel) an additional three to five degrees.
- Reduces radiated heat. The constant flow of cool air absorbs heat from all exposed surfaces and results in a reduction of the heat radiated to the human body.
- Provides 100 percent fresh, revitalizing air.
- Filters air. Removes dust, pollen and foreign matter.
Advantages of Evaporative Air Cooling
- Low initial cost of equipment.
- Simple, low-cost installation.
- Low cost of operation and maintenance.
- Maximum comfort when it's needed. The hotter the day, the greater the cooling.
- 100 percent fresh, cooled, filtered air. Air is never recirculated.
- Fresh-air ventilation, without cooling, at any time-just turn off the water
Cooling for Industrial Hot Spots
The cooling of people in industrial activity may take the form of general space cooling, or spot cooling of individuals. The occupant density and the nature of the structure determine the approach to be taken. Where worker density is high and structures have low ceiling heights, general space cooling is recommended. Where the worker density is low and building volume large, spot cooling of the individual is more practical. The field of application is much broader in this use than for residence cooling. A list of potential applications would include relief cooling of individuals in various metal working operations, such as forge shops and foundries, the rubber industry around tire molds and mills, laundry and dry cleaning establishments, the textile industry, and other industrial operations in which heat gain from the process is a major heat source.
For spot evaporative cooling of workers, the volume of air per worker will vary from 500 CFM to 2000 CFM depending on the intensity of the heat source. The natural air path should be directed toward the worker's Waistline from a point at about shoulder level. The air velocity around the Worker should range from 400 to 1000 FPM depending on the need. The air outlet should be from two to five feet from the worker and should be provided with means for deflecting the air both vertically and horizontally. This permits the worker to adjust the airflow to suit his needs.
Normally, the evaporative cooler should be located so it takes in only outside air. However, there may be instances, as in large manufacturing plants with high ceilings, where this is not practical. In such cases it is usually satisfactory to place the cooler inside the building near the point of application - if provision is made, by means of monitor tops or other construction, for the exhaust of large quantities of air, and if the air volume supplied by the coolers is small in comparison to the volume being exhausted.
Cooling for Industrial Processes
Many types of industrial processes can benefit from the application of evaporative cooling.
Process applications where evaporative cooling has been found to provide satisfactory results include:
- Cooling of parts leaving paint or enameling ovens, cooling bread from large ovens, etc. This application can speed up production considerably and reduce the space need for storage while parts or products are cooling.
- Cooling of refrigeration condensers and compressor rooms. In areas of high dry bulb temperature, the use of evaporatively cooled air can significantly reduce head pressure on compressors.
- Cooling of molded plastic parts leaving the molding press. This application can eliminate the need for cooling frames or forms and shorten the interval before packaging the parts.
- Cooling of large industrial motors, permitting a significant increase in power output.
- Cooling of hosiery and textile mills. Evaporative cooling helps prevent the dangerous buildup of static electrical charges in such mills.
- Cooling of produce barns, providing conditions that are more comfortable for employees as well as better conditions for the produce on the tables. Such buildings require large volumes of air to overcome the losses through open doors or sidewalls, making evaporative cooling the only practical way to provide comfort.
In the above applications, the evaporative cooler not only supplies cooled air but also supplies air free of dust and other particulate.
|
