It has been suggested that evaporative cooling be merged into this article or section. (Discuss)

Evaporative coolers (also called air, swamp, or desert coolers) devices which use simple evaporation of water in air. They differ from refrigeration or absorption air conditioning, which use the vapor-compression or absorption refrigeration cycles. In the United States, small-scale evaporative coolers are called swamp coolers by some users due to the humid air conditions produced. The name sump cooler is also used. Air washers and wet cooling towers utilize the same principles as evaporative coolers, but are optimized for purposes other than air cooling. Image File history File links Mergefrom. ... Evaporative cooling is a system in which latent heat of evaporation is used to carry heat away from an object to cool it. ... Vaporization redirects here. ... Refrigeration is the process of removing heat from an enclosed space, or from a substance, and rejecting it elsewhere for the primary purpose of lowering the temperature of the enclosed space or substance and then maintaining that lower temperature. ... Absorptive refrigeration utilizes a source of heat to provide the energy needed to drive the cooling process. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... Vapor-compression refrigeration[1][2] is one of the many refrigeration methods available for use. ...

Evaporative cooling is especially well suited for climates where the air is hot and humidity is low. For example, in the United States, the western/mountain states are good locations, with swamp coolers very prevalent in cities like Denver, Salt Lake City, Albuquerque, El Paso and Phoenix, where sufficient water is available. Evaporative air conditioning is also popular and well suited to the southern (temperate) part of Australia. In dry climates, the installation and operating cost of an evaporative cooler can be much lower than refrigerative air conditioning, often by 80% or so. But evaporative cooling and vapor-compression air conditioning are sometimes used in combination to yield optimal performance. Some evaporative coolers may also serve as humidifiers in the heating season. Evaporative cooling is a system in which latent heat of evaporation is used to carry heat away from an object to cool it. ... The term humidity is usually taken in daily language to refer to relative humidity. ... This article refers to the state capital of Colorado. ... The Salt Lake Temple of The Church of Jesus Christ of Latter-day Saints is Salt Lake Citys top tourist draw. ... This article is about the largest city of New Mexico. ... This article needs cleanup. ... Nickname: Location in Maricopa County and the state of Arizona Coordinates: , Country State County Maricopa Incorporated February 25, 1881 Government  - Type Council-Manager  - Mayor Phil Gordon (D) Area  - City  515. ... A humidifier is a household appliance that increases humidity (moisture) in a single room or in the entire home. ...

In moderate humidity locations there are many cost-effective uses for evaporative cooling, in addition to their widespread use in dry climates. For example, industrial plants, commercial kitchens, laundries, dry cleaners, greenhouses, spot cooling (loading docks, warehouses, factories, construction sites, athletic events, workshops, garages, and kennels) and confinement farming (poultry ranches, hog, and dairy) all often employ evaporative cooling. In highly humid climates, evaporative cooling may have little thermal comfort benefit beyond the increased ventilation and air movement it provides. Large institutions that require a constant flow of clean linen will often employ the services of an industrial laundry. ... This article or section is in need of attention from an expert on the subject. ... The Royal Greenhouses of Laeken. ... Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ... Ventilation good and very bad Ventilation is air circulation of air, typically between a room, a tunnel, etc. ...

History

Civilizations throughout the ages have found ingenious ways to combat the heat in their region. An earlier form of air cooling, the windcatcher (Bâd gir), was invented in Persia (Iran) thousands of years ago in the form of wind shafts on the roof, which caught the wind and passed it through water and blew the cooled air into the building.^[1] Nowadays Iranians have changed the windcatcher into an evaporative cooler (Coolere Âbi) and use it widely. There are 9,000,000 evaporative coolers in central Iran, and in just the first two months of year 1385 in the (Persian/Iranian calender) (April–May 2006) 130,000 evaporative coolers were sold in Iran. A windcatcher (Badgir; بادگیر) is a traditional Persian architectural device used for many centuries to create natural ventilation in buildings. ... For other uses of this term see: Persia (disambiguation) The Persian Empire is the name used to refer to a number of historic dynasties that have ruled the country of Persia (Iran). ... A windcatcher (Badgir; بادگیر) is a traditional Persian architectural device used for many centuries to create natural ventilation in buildings. ... The Iranian calendar (Persian: ), also known as Persian calendar or (mistakenly) the Jalāli Calendar is an astronomical solar calendar currently used in Iran and Afghanistan as the main official calendar. ...

Evaporative cooler designs

Direct Evaporative Cooling (open circuit) is used to lower the temperature of air by using latent heat of evaporation, changing water to vapor. In this process, the energy in the air does not change. Warm dry air is changed to cool moist air. Heat in the air is used to evaporate water.

Indirect Evaporative Cooling (closed circuit) is similar to direct evaporative cooling, but uses some type of heat exchanger. The cooled moist air never comes in direct contact with the conditioned environment. A heat exchanger is a device built for efficient heat transfer from one fluid to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are directly contacted. ...

Two-stage Evaporative Cooling, or Indirect-Direct. Traditional evaporative coolers use only a fraction of the energy of vapor-compression or absorption air conditioning systems. Unfortunately, except for in very dry climates, they may increase humidity to a level that makes occupants uncomfortable. Two-stage evaporative coolers do not produce humidity levels as high as that produced by traditional single-stage evaporative coolers.

In the first stage of a two-stage cooler, warm air is pre-cooled indirectly without adding humidity (by passing inside a heat exchanger that is cooled by evaporation on the outside). In the direct stage, the precooled 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 (because cooler air can’t hold as much moisture as warmer air). The result, according to manufacturers, is cool air with a relative humidity between 50 and 70 percent, depending on the climate, compared to a traditional system that produces about 80 percent relative humidity air.

Typical

Evaporative cooler illustration

Typically, residential and industrial evaporative coolers use direct evaporation and can be described as an enclosed metal or plastic box with vented sides containing a centrifugal fan or 'blower', electric motor with pulleys (known as 'sheaves' in HVAC]), and a water pump to wet the evaporative cooling pads. The units can be mounted on the roof (down draft, or downflow), or exterior walls or windows (side draft, or horizontal flow) of buildings. To cool, the fan draws ambient air through vents on the unit's sides and through the damp pads. Heat in the air evaporates water from the pads which are constantly re-dampened to continue the cooling process. Thus cooled, moist air is then delivered to the building via a vent in the roof or wall. Download high resolution version (879x620, 105 KB)Swamp cooler illustration, made by User:Buster2058. ... Download high resolution version (879x620, 105 KB)Swamp cooler illustration, made by User:Buster2058. ... Figure 1: Components of a centrifugal fan A centrifugal fan is a mechanical device for moving air or other gases. ... HVAC may also stand for High-voltage alternating current HVAC systems use ventilation air ducts installed throughout a building that supply conditioned air to a room through rectangular or round outlet vents, called diffusers; and ducts that remove air from return-air grilles Fire-resistance rated mechanical shaft with HVAC...

Because the cooling air originates outside the building, one or more large vents must exist to allow air to move from inside to outside. Air should only be allowed to pass once through the system, or the cooling effect will decrease. This is due to the air reaching the saturation point. Often 15 or so air changes per hour (ACHs) occur in spaces served by evaporative coolers. The term humidity is usually taken in daily language to refer to relative humidity. ...

Cooler pads

Traditionally, evaporative cooler pads consist of excelsior (wood wool) (aspen wood fiber) inside a containment net, but more modern materials, such as some plastics and melamin paper, are entering use as cooler-pad media. Wood absorbs some of the water, which allows the wood fibers to cool passing air to a lower temperature than some synthetic materials. The thickness of the padding media plays a large part in cooling efficiency, allowing longer air contact. For example, an eight-inch-thick pad with its increased surface area will be more efficient than a one-inch pad. U.S. Patent 6,183,579 on a method of making cooling pads of excelsior, and illustrating such a pad Excelsior is a wood product made of aspen fibers, used in packaging, cushioning, stuffing of stuffed animals, and for the cooling pads in home evaporative cooling systems known as swamp... For other uses, see Aspen (disambiguation). ... For other uses, see Wood (disambiguation). ... Fiber or fibre[1] is a class o f materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread. ... Melamin resin or melamine formaldehyde (also incorrectly, melamine) is a plastic material made from melamine and formaldehyde by polymerization. ...

Evaporative (wet) cooling towers

Didcot Power Station Cooling towers

Main article: Cooling tower

Cooling towers are structures for cooling water or other working media to near-ambient wet bulb temperature. Wet cooling towers operate on the evaporative cooling principle, but are optimized to cool the water rather than the air. Cooling towers can often be found on large buildings or on industrial sites. They reject heat to the environment from chillers, industrial processes, or the Rankine power cycle, for example. Image File history File links Size of this preview: 800 × 485 pixelsFull resolution (893 × 541 pixel, file size: 103 KB, MIME type: image/jpeg)The cooling towers of Didcot Power Station taken from a train just outside of Didcot Parkway Station. ... Image File history File links Size of this preview: 800 × 485 pixelsFull resolution (893 × 541 pixel, file size: 103 KB, MIME type: image/jpeg)The cooling towers of Didcot Power Station taken from a train just outside of Didcot Parkway Station. ... Image 1: Natural draft wet cooling hyperboloid towers at Didcot Power Station, UK Image 2: A mechanical induced draft cooling tower In rare cases, a plants cooling towers have even been painted to improve public perception as with the Cruas Nuclear Power Plant. ... Image 1: Natural draft wet cooling hyperboloid towers at Didcot Power Station, UK Image 2: A mechanical induced draft cooling tower In rare cases, a plants cooling towers have even been painted to improve public perception as with the Cruas Nuclear Power Plant. ... The Rankine cycle is a thermodynamic cycle. ...

Misting systems

Photo of Misting fan.

Misting systems work by forcing water via a high pressure pump and tubing through a brass and stainless steel mist nozzle that has an orifice of about 5 micrometres, thereby producing a micro-fine mist. The water droplets that create the mist are so small that they instantly flash evaporate. Flash evaporation can reduce the surrounding air temperature by as much as 35°F (20°C) in just seconds [1]. For patio systems, it is ideal to mount the mist line approximately 8 to 10 feet above the ground for optimum cooling. Misting is used for many different applications including orchids, pets, livestock, kennels, insect control, odor control, zoos, veterinary clinics, produce cooling, greenhouses, etc. Image File history File links MistingFan. ... Image File history File links MistingFan. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... The flash (or partial) evaporation is one of the simplest unit operations. ...

Misting fans

A misting fan is similar to a humidifier. A fan blows a fine mist of water into the air. If the air is not too humid, the water evaporates, absorbing heat from the air, allowing the misting fan to work as an air conditioner. A misting fan may be used outdoors, especially in a dry climate. A humidifier is a household appliance that increases humidity (moisture) in a single room or in the entire home. ...

Performance

Understanding evaporative cooling performance requires an understanding of psychrometrics. Evaporative cooling performance is dynamic due to changes in external temperature and humidity level. Under typical operating conditions, an evaporative cooler will nearly always deliver air cooler than 27°Celsius (80°Fahrenheit). A typical residential 'swamp cooler' in good working order should cool air to within 3°C–4°C (6°F–8°F) of the wet-bulb temperature. For the parapsychology phenomenon of distance knowledge, see psychometry. ... For other uses, see Celsius (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ... Wet-bulb temperature ...

In practice, it may be difficult to predict swamp cooler performance from standard weather report information, because weather reports usually contain the dewpoint and relative humidity, but not the wet bulb temperature. However, you may use either of two methods to estimate performance: The dew point or dewpoint of a given parcel of air is the temperature to which the parcel must be cooled, at constant barometric pressure, for the water vapor component to condense into water, called dew. ... A hygrometer used to measure the humidity of air. ...

• Use a Psychrometric chart to calculate wet bulb temperature, and then add 6°F–8°F as described above.
• Use a rule of thumb which estimates that the wet bulb temperature is approximately equal to the ambient temperature, minus two thirds of the difference between the ambient temperature and the dewpoint. As before, add 6°F–8°F as described above.

Some rough examples clarify this relationship. A rule of thumb is an easily learned and easily applied procedure for approximately calculating or recalling some value, or for making some determination. ...

• At 32°C (90°F) and 15% relative humidity, air may be cooled to nearly 16°C (60°F). The dew point for these conditions is 2°C (~36°F).
• At 32°C (90°F) and 50% relative humidity, air may be cooled to about 24°C (75°F). The dew point for these conditions is 20°C (~68°F).
• At 40°C (105°F) and 15% relative humidity, air may be cooled to nearly 21°C (70°F). The dew point for these conditions is 8°C (~47°F).

Because evaporative coolers perform best in dry conditions, they are widely used and most effective in arid, desert regions such as the southwestern USA and northern Mexico. This article is about arid terrain. ... The Southwest region of the United States is drier than the adjoining Midwest in weather; the population is less dense and, with strong Spanish-American and Native American components, more ethnically varied than neighboring areas. ...

(Cooling examples extracted from the June 25, 2000 University of Idaho publication, "Homewise"). is the 176th day of the year (177th in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday. ...

Comparison to phase-change air conditioning

Advantages

Less expensive to install

• Estimated cost for installation is 1/8 to 1/2 that of refrigerated air conditioning

Less expensive to operate

• Estimated cost of operation is 1/4 that of refrigerated air.
• Power consumption is limited to the fan and water pump vs. compressors, pumps, and blowers.

Ventilation air A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. ... A pump is a mechanical device used to move liquids or gases. ... For other uses, see Fan. ...

• The constant and high volumetric flow rate of air through the building reduces the age-of-air in the building dramatically.

Disadvantages

Performance

• High temperature, high humidity outside conditions decrease the cooling capability of the evaporative cooler.
• No dehumidification. Traditional air conditioners remove moisture from the air, which is usually a design requirement except in very dry locations. Evaporative cooling adds moisture, which, in dry climates, may improve thermal comfort.

Comfort A dehumidifier is a household appliance that reduces the level of humidity in the air. ... Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ...

• The air supplied by the evaporative cooler is typically 80–90% relative humidity.
• Very humid air reduces the evaporation rate of moisture from the skin, nose, lungs, and eyes.
• High humidity in air accelerates corrosion. This can considerably shorten the life of electronic and other equipment.
• High humidity in air may cause condensation. This can be a problem for some situations (e.g., electrical equipment, computers, paper/books, old wood).

Water For the hazard, see corrosive. ... For other uses, see Condensation (disambiguation). ...

• Evaporative coolers require a constant supply of water to wet the pads.
• Water high in mineral content will leave mineral deposits on the pads and interior of the cooler. Water softeners, bleed-off, and refill systems may reduce this problem.
• The water supply line needs protection against freeze bursting during off-season, winter temperatures. The cooler itself needs to be drained too, as well as cleaned periodically and the pads replaced.

Miscellaneous For other uses, see Mineral (disambiguation). ... A water softener reduces calcium or magnesium concentration in hard water. ...

• Pollen, odors, and other outdoor contaminants may be blown into the building unless sufficient filtering is in place.
• The vents that allow air to exit the building may pose a physical security risk.
• Asthma patients may need to avoid evaporatively cooled environments.

SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomoea purpurea), prairie hollyhock (Sidalcea malviflora), oriental lily (Lilium auratum), evening primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... Physical security describes measures that prevent or deter attackers from accessing a facility, resource, or information stored on physical media. ...

Health Concerns

Evaporative coolers, like all equipment, require maintenance. Legionnaire's Disease, caused by the bacterium Legionella pneumophila and related bacteria ... "may be found in purpose built water systems such as cooling towers, evaporative condensers..." ^[2] As such, it is critical that evaporative coolers be properly installed and adequately maintained according to their manufacturers' recommendations. Legionellosis is an infectious disease caused by bacteria belonging to the genus Legionella. ... Species Legionella adelaidensis Legionella anisa Legionella beliardensis Legionella birminghamensis Legionella bozemanii Legionella brunensis Legionella busanensis Legionella cherrii Legionella cincinnatiensis Legionella donaldsonii Legionella drancourtii Legionella drozanskii Legionella erythra Legionella fairfieldensis Legionella fallonii Legionella feeleii Legionella geestiana Legionella gratiana Legionella gresilensis Legionella hackeliae Legionella israelensis Legionella jamestowniensis Legionella jordanis Legionella lansingensis Legionella... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ...

See also

• Air conditioning
• Cooling tower
• Cooling tower system
• Pot-in-pot refrigerator
• Psychrometrics
• Dew point
• Evaporation
• Humidity
• HVAC
• Architectural engineering
• Building engineering

Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... Image 1: Natural draft wet cooling hyperboloid towers at Didcot Power Station, UK Image 2: A mechanical induced draft cooling tower In rare cases, a plants cooling towers have even been painted to improve public perception as with the Cruas Nuclear Power Plant. ... The primary use of large, industrial wet cooling towers is to lower the temperature of the cooling water used in power plants, petroleum refineries, petrochemical plants, natural gas processing plants and other industrial facilities. ... The pot-in-pot refrigerator, also known as a Zeer pot is a way of keeping food cool without electricity. ... For the parapsychology phenomenon of distance knowledge, see psychometry. ... The dew point (or dewpoint) is the temperature which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water. ... Vaporization redirects here. ... The term humidity is usually taken in daily language to refer to relative humidity. ... HVAC may also stand for High-voltage alternating current HVAC systems use ventilation air ducts installed throughout a building that supply conditioned air to a room through rectangular or round outlet vents, called diffusers; and ducts that remove air from return-air grilles Fire-resistance rated mechanical shaft with HVAC... An architectural engineer applies the skills of many engineering disciplines to the design, construction, operation, maintenance, and renovation of buildings while paying attention to their impacts on the surrounding environment. ... // Building engineering: a discipline for the modern era Building engineering, commonly known in the US as architectural engineering, is an emerging engineering discipline that concerns with the planning, design, construction, operation, renovation, and maintenance of buildings, as well as with their impacts on the surrounding environment. ...

References

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 195th day of the year (196th in leap years) in the Gregorian calendar. ...

External links

• Holladay, April (2001). A swamp cooler cools air by evaporation. WonderQuest Weekly Q&A science column. USAToday.com. Retrieved on 2006-07-14.
• Mithra, S. (2006). What is a Swamp Cooler?. clear answers for common questions. Wisegeek.com. Retrieved on 2006-07-14.
• PATH Tech Inventory: Two Stage Evaporative Cooler
• PATH Tech Inventory: Evaporative Cooler