air conditioning - wikipedia, the free encyclopedia

8/16/2019 Air Conditioning - Wikipedia, The Free Encyclopedia

1/20

12/1/2014 Air conditioning - Wikipedia, the free encyclopedia

http://en.wikipedia.org/wiki/Air_conditioning

Air conditioning units outside a building

Window unit inside a room

Air conditioningFrom Wikipedia, the f ree encyclopedia

"Air conditioning is a process of controlling thetemperature of air being supplied to a particular spacethrough using the process of Ventillation, Fan, cooler and humidification." The device or apparatus used to

bring out this purpose is termed as Air-Conditioner. Airconditioning (often referred to as A/C , AC or aircon) isthe process of altering the properties of air (primarilytemperature and humidity) to more comfortableconditions, typically with the aim of distri buting theconditioned air to an occu pied space to improve thermalcomfort and indoor air quality.

Contents1 Overview

2 Histor y

2.1 Development of mechanical cooling

2.2 Electromechanical cooling

2.3 Refrigerant development

3 Operating principles

3.1 Refrigeration cycle3.1.1 Heat pump

3.2 Evaporative cooling

3.3 Free cooling

4 Humidity control

4.1 Dehumidification and cooling

4.2 Dehumidification only

5 Energy transfer

5.1 Seasonal energy efficiency ratio

6 Installation types

6.1 Window unit and packaged terminal

6.2 Split systems

6.2.1 Mini-split (ductless) system

6.2.2 Central (ducted) air

conditioning

http://en.wikipedia.org/wiki/Thermal_comforthttp://en.wikipedia.org/wiki/Temperaturehttp://en.wikipedia.org/wiki/Humidityhttp://en.wikipedia.org/wiki/Airhttp://en.wikipedia.org/wiki/Temperaturehttp://en.wikipedia.org/wiki/File:Panasonic_aircon_CW-A56S2.jpghttp://en.wikipedia.org/wiki/Humidityhttp://en.wikipedia.org/wiki/File:2008-07-11_Air_conditioners_at_UNC-CH.jpghttp://en.wikipedia.org/wiki/Thermal_comforthttp://en.wikipedia.org/wiki/Indoor_air_quality


2/20


http://en.wikipedia.org/wiki/Air_conditioning 2

6.3 Portable units

6.3.1 Portable split system

6.3.2 Portable hose system

6.3.3 Portable evaporative system

7 Uses

7.1 Comfort applications

7.1.1 Domestic use

7.2 Process applications

8 Health issues

9 Environmental impact

9.1 Power consumption

9.2 Refrigerants

10 See also

11 References

12 External links

Overview

In common use, an air conditioner is a device that lowers the air temperature. The cooling is typicallyachieved through a refrigeration cycle, but sometimes evaporation or free cooling is used. Air conditioning

systems can also be made based on desiccants.[1]

In the most general sense, air conditioning can refer to any form of technology that modifies the conditionof air (heating, cooling, (de-)humidification, cleaning, ventilation, or air movement). However, inconstruction, such a complete system of heating, ventilation, and air conditioning is referred to as HVAC

(as opposed to AC ).[2]

History

The basic concept behind air conditioning is said to have been applied in ancient Egypt, where reeds werehung in windows and were moistened with trickling water. The evaporation of water cooled the air blowinthrough the window. This process also made the air more humid, which can be beneficial in a dry desertclimate. In Ancient Rome, water from aqueducts was circulated through the walls of certain houses to coolthem. Other techniques in medieval Persia involved the use of cisterns and wind towers to cool buildings

during the hot season.[3]

Modern air conditioning emerged from advances in chemistry during the 19th century, and the first large-scale electrical air conditioning was invented and used in 1902 by American inventor Willis Carrier. Theintroduction of residential air conditioning in the 1920s helped enable the great migration to the Sun Belt inthe United States.

http://en.wikipedia.org/wiki/Ancient_Romehttp://en.wikipedia.org/wiki/Cisternhttp://en.wikipedia.org/wiki/Cooling_(disambiguation)http://en.wikipedia.org/wiki/Willis_Carrierhttp://en.wikipedia.org/wiki/Wind_towerhttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Evaporative_coolerhttp://en.wikipedia.org/wiki/Ventilation_(architecture)http://en.wikipedia.org/wiki/HVAChttp://en.wikipedia.org/wiki/Free_coolinghttp://en.wikipedia.org/wiki/Aqueduct_(watercourse)http://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Refrigeration_cyclehttp://en.wikipedia.org/wiki/Sun_Belthttp://en.wikipedia.org/wiki/Constructionhttp://en.wikipedia.org/wiki/Chemistryhttp://en.wikipedia.org/wiki/Persia


3/20



Three-quarters scale model of

Gorrie's ice machine John Gorrie

State Museum, Florida

Development of mechanical cooling

The 2nd-century Chinese inventor Ding Huan (fl 180) of the HanDynasty invented a rotary fan for air conditioning, with seven

wheels 3 m (9.8 ft) in diameter and manually powered.[4] In 747,Emperor Xuanzong (r. 712–762) of the Tang Dynasty (618–907)had the Cool Hall ( Liang Tian) built in the imperial palace, which

the Tang Yulin describes as having water-powered fan wheels for air conditioning as well as rising jet streams of water from fountains.During the subsequent Song Dynasty (960–1279), written sourcesmentioned the air conditioning rotary fan as even more widely

used.[5]

In the 17th century, Cornelis Drebbel demonstrated "TurningSummer into Winter" for James I of England by adding salt to

water.[6]

In 1758, Benjamin Franklin and John Hadley, a chemistry professor at Cambridge University, conducted an experiment to explore the principle of evaporation as a means to rapidly cool an object.Franklin and Hadley confirmed that evaporation of highly volatileliquids (such as alcohol and ether) could be used to drive down thetemperature of an object past the freezing point of water. Theyconducted their experiment with the bulb of a mercury thermometer as their object and with a bellows usedto speed-up the evaporation. They lowered the temperature of the thermometer bulb down to −14 °C (7 °F)while the ambient temperature was 18 °C (64 °F). Franklin noted that, soon after they passed the freezing

point of water 0 °C (32 °F), a thin film of ice formed on the surface of the thermometer's bulb and that the

ice mass was about a quarter-inch thick when they stopped the experiment upon reaching −14 °C (7 °F).Franklin concluded: "From this experiment one may see the possibility of freezing a man to death on a

warm summer's day"[7]

In 1820, English scientist and inventor Michael Faraday discovered that compressing and liquefyingammonia could chill air when the liquefied ammonia was allowed to evaporate. In 1842, Florida physicianJohn Gorrie used compressor technology to create ice, which he used to cool air for his patients in his

hospital in Apalachicola, Florida.[8] He hoped to eventually use his ice-making machine to regulate the

temperature of buildings. He even envisioned centralized air conditioning that could cool entire cities.[9]

Though his prototype leaked and performed irregularly, Gorrie was granted a patent in 1851 for his ice-

making machine.[10] His hopes for its success vanished soon afterwards when his chief financial backer died; Gorrie did not get the money he needed to develop the machine. According to his biographer, VivianM. Sherlock, he blamed the "Ice King", Frederic Tudor, for his failure, suspecting that Tudor had launcheda smear campaign against his invention. Dr. Gorrie died impoverished in 1855, and the idea of air conditioning went away for 50 years.

Since prehistoric times, snow and ice were used for cooling. The business of harvesting ice during winter

and storing for use in summer became popular towards the late 19th century.[11] This practice was replaced by mechanical ice-making machines.

http://en.wikipedia.org/wiki/Fan_(mechanical)http://en.wikipedia.org/wiki/Benjamin_Franklinhttp://en.wikipedia.org/wiki/Frederic_Tudorhttp://en.wikipedia.org/wiki/Inventorhttp://en.wikipedia.org/wiki/John_Gorrie_State_Museumhttp://en.wikipedia.org/wiki/Tang_Dynastyhttp://en.wikipedia.org/wiki/John_Hadley_(chemist)http://en.wikipedia.org/wiki/Floridahttp://en.wikipedia.org/wiki/Cambridge_Universityhttp://en.wikipedia.org/wiki/Smear_campaignhttp://en.wikipedia.org/wiki/Cornelis_Drebbelhttp://en.wikipedia.org/wiki/File:Gorriemuseumapalachicola_ice_mchn1.jpghttp://en.wikipedia.org/wiki/Song_Dynastyhttp://en.wikipedia.org/wiki/James_I_of_Englandhttp://en.wikipedia.org/wiki/History_of_China#Ancient_Chinahttp://en.wikipedia.org/wiki/Hydraulicshttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Michael_Faradayhttp://en.wikipedia.org/wiki/Apalachicola,_Floridahttp://en.wikipedia.org/wiki/Floruithttp://en.wikipedia.org/wiki/John_Gorriehttp://en.wikipedia.org/wiki/Han_Dynastyhttp://en.wikipedia.org/wiki/Emperor_Xuanzong_of_Tanghttp://en.wikipedia.org/wiki/United_Kingdom_of_Great_Britain_and_Ireland


4/20



Willis Carrier

James Harrison's first mechanical ice-making machine began operation in 1851 on the banks of the BarwoRiver at Rocky Point in Geelong (Australia). His first commercial ice-making machine followed in 1854,and his patent for an ether vapor compression refrigeration system was granted in 1855. This novel systemused a compressor to force the refrigeration gas to pass through a condenser, where it cooled down andliquefied. The liquefied gas then circulated through the refrigeration coils and vaporised again, coolingdown the surrounding system. The machine employed a 5 m (16 ft.) flywheel and produced 3,000kilograms (6,600 lb) of ice per day.

Though Harrison had commercial success establishing a second ice company back in Sydney in 1860, helater entered the debate over how to compete against the American advantage of unrefrigerated beef sales tthe United Kingdom. He wrote: "Fresh meat frozen and packed as if for a voyage, so that the refrigerating

process may be continued for any required period", and in 1873 prepared the sailing ship Norfolk for anexperimental beef shipment to the United Kingdom. His choice of a cold room system instead of installinga refrigeration system upon the ship itself proved disastrous when the ice was consumed faster than

expected.[12]

Electromechanical cooling

In 1902, the first modern electrical air conditioning unit was invented byWillis Carrier in Buffalo, New York. After graduating from CornellUniversity, Carrier found a job at the Buffalo Forge Company. While there,he began experimenting with air conditioning as a way to solve anapplication problem for the Sackett-Wilhelms Lithographing and PublishingCompany in Brooklyn, New York. The first air conditioner, designed and

built in Buffalo by Carrier, began working on 17 July 1902.

Designed to improve manufacturing process control in a printing plant,Carrier's invention controlled not only temperature but also humidity.

Carrier used his knowledge of the heating of objects with steam andreversed the process. Instead of sending air through hot coils, he sent itthrough cold coils (filled with cold water). The air was cooled, and therebythe amount of moisture in the air could be controlled, which in turn madethe humidity in the room controllable. The controlled temperature andhumidity helped maintain consistent paper dimensions and ink alignment.Later, Carrier's technology was applied to increase productivity in the workplace, and The Carrier Air Conditioning Company of America was formed to meet rising demand. Over time, air conditioning came t

be used to improve comfort in homes and automobiles as well. Residential sales expanded dramatically inthe 1950s.

In 1906, Stuart W. Cramer of Charlotte, North Carolina was exploring ways to add moisture to the air in hitextile mill. Cramer coined the term "air conditioning", using it in a patent claim he filed that year as ananalogue to "water conditioning", then a well-known process for making textiles easier to process. Hecombined moisture with ventilation to "condition" and change the air in the factories, controlling thehumidity so necessary in textile plants. Willis Carrier adopted the term and incorporated it into the name ohis company.

http://en.wikipedia.org/wiki/Stuart_W._Cramerhttp://en.wikipedia.org/wiki/Cornell_Universityhttp://en.wikipedia.org/wiki/Charlotte,_North_Carolinahttp://en.wikipedia.org/wiki/Buffalo_Forge_Companyhttp://en.wikipedia.org/wiki/Carrier_Corporationhttp://en.wikipedia.org/wiki/Temperaturehttp://en.wikipedia.org/wiki/File:Willis_Carrier_1915.jpghttp://en.wikipedia.org/wiki/Willis_Carrierhttp://en.wikipedia.org/wiki/Buffalo,_New_Yorkhttp://en.wikipedia.org/wiki/Automobilehttp://en.wikipedia.org/wiki/Humidityhttp://en.wikipedia.org/wiki/Printinghttp://en.wikipedia.org/wiki/Inventionhttp://en.wikipedia.org/wiki/Willis_Carrierhttp://en.wikipedia.org/wiki/James_Harrison_(engineer)http://en.wikipedia.org/wiki/Brooklyn,_New_York


5/20



A modern R-134a hermetic

refrigeration compressor

Shortly thereafter, the first private home to have air conditioning was built in Chapel Hill, North Carolina 1933. Realizing that air conditioning would one day be a standard feature of private homes, particularly inregions with warmer climate, David St. Pierre DuBose (1898-1994) designed a network of ductwork andvents for his home Meadowmont , all disguised behind intricate and attractive Georgian-style openmoldings. This building is believed to be one of the first private homes in the United States equipped for

central air conditioning.[13]

In 1945, Robert Sherman of Lynn, Massachusetts invented a portable, in-window air conditioner thatcooled, heated, humidified, dehumidified, and filtered the air. The idea was subsequently stolen by a largemanufacturer. Sherman did not have the resources to fight the big corporation in court and thus never

received any money or recognition. He died in 1962.[14]

Refrigerant development

The first air conditioners and refrigerators employed toxic or flammable gases, such as ammonia, methyl chloride, or propane,that could result in fatal accidents when they leaked. Thomas

Midgley, Jr. created the first non-flammable, non-toxicchlorofluorocarbon gas, Freon, in 1928. The name is a trademark name owned by DuPont for any Chlorofluorocarbon (CFC),Hydrochlorofluorocarbon (HCFC), or Hydrofluorocarbon (HFC)refrigerant. The refrigerant names include a number indicating themolecular composition (e.g. R-11, R-12, R-22, R-134A). The blendmost used in direct-expansion home and building comfort cooling isan HCFC known as R-22.

R-12 was the most common blend used in automobiles in the USuntil 1994, when most designs changed to R-134A due to the ozone-depleting potential of R-12. R-11 and R-12 are no longer manufactured in the US for this type of application, so the only source for air-conditioning repair purposes is the cleaned and purified gas recoverefrom other air conditioner systems. Several non-ozone-depleting refrigerants have been developed asalternatives, including R-410A. It was first commercially used by Carrier Corp. under the brand name

Puron.

Modern refrigerants have been developed to be more environmentally safe than many of the earlychlorofluorocarbon-based refrigerants used in the early- and mid-twentieth century. These include asHCFCs (R-22, used in most U.S. homes even before 2011) and HFCs (R-134a, used in most cars) havereplaced most CFC use. HCFCs, in turn, are supposed to have been in the process of being phased out

under the Montreal Protocol and replaced by hydrofluorocarbons (HFCs) such as R-410A, which lack chlorine. HFCs, however, contribute to climate change problems. Moreover, policy and political influence

by corporate executives resisted change.[15][16] In fact, since corporate executives insisted that noalternatives to HFCs existed, the non-governmental organization (NGO) Greenpeace solicited a Europeanlaboratory to research an alternative ozone- and climate-safe refrigerant in 1992, gained patent rights to a

hydrocarbon mix of isopentane and isobutane, but then left the technology as open access.[17][18] Their activist marketing first in Germany led to companies like Whirlpool, Bosch, and later LG and others toincorporate the technology throughout Europe, then Asia, although the corporate executives resisted inLatin America, so that it arrived in Argentina produced by a domestic firm in 2003, and then finally with

http://en.wikipedia.org/wiki/Chlorodifluoromethanehttp://en.wikipedia.org/wiki/Lynn,_Massachusettshttp://en.wikipedia.org/wiki/Chlorofluorocarbonhttp://en.wikipedia.org/wiki/Refrigeranthttp://en.wikipedia.org/wiki/Montreal_Protocolhttp://en.wikipedia.org/wiki/Methyl_chloridehttp://en.wikipedia.org/wiki/DuPonthttp://en.wikipedia.org/wiki/Thomas_Midgley,_Jr.http://en.wikipedia.org/wiki/Chlorodifluoromethanehttp://en.wikipedia.org/wiki/Freonhttp://en.wikipedia.org/wiki/R-410Ahttp://en.wikipedia.org/wiki/Dichlorodifluoromethanehttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/R-134ahttp://en.wikipedia.org/wiki/R-134ahttp://en.wikipedia.org/wiki/1,1,1,2-Tetrafluoroethanehttp://en.wikipedia.org/wiki/Central_air_conditioninghttp://en.wikipedia.org/wiki/Hydrofluorocarbonhttp://en.wikipedia.org/wiki/HCFChttp://en.wikipedia.org/wiki/R-410Ahttp://en.wikipedia.org/wiki/HCFChttp://en.wikipedia.org/wiki/Chlorofluorocarbonhttp://en.wikipedia.org/wiki/Propanehttp://en.wikipedia.org/wiki/Hydrofluorocarbonhttp://en.wikipedia.org/wiki/Refrigeratorhttp://en.wikipedia.org/wiki/Gas_compressorhttp://en.wikipedia.org/wiki/File:Embraco_compressor.jpghttp://en.wikipedia.org/wiki/Trademark


6/20



A simple stylized diagram of the

refrigeration cycle: 1) condensing

coil, 2) expansion valve,

3) evaporator coil, 4) compressor

Capillary expansion valve connection

to evaporator inlet. Notice frost

formation

giant Bosch's production in Brazil by 2004.[19][20] In 1995, Germany made CFC refrigerators illegal.[21] DuPont and other companies blocked the refrigerant in the U.S. with the U.S. E.P.A., disparaging the approac

as "that German technology."[20][22] Nevertheless, in 2004, Greenpeace worked with multinationalcorporations like Coca-Cola and Unilever, and later Pepsico and others, to create a corporate coalition

called Refrigerants Naturally!.[21][23][24] Then, four years later, Ben & Jerry's of Unilever and General

Electric began to take steps to support production and use in the U.S. [25][26] Only in 2011 did the E.P.A.

finally decide in favor of the ozone- and climate-safe refrigerant for U.S. manufacture.[17][27][28]

Operating principles

Refrigeration cycle

In the refrigeration cycle, heat is transported from a colder locationto a hotter area. As heat would naturally flow in the oppositedirection, work is required to achieve this. A refrigerator is anexample of such a system, as it transports the heat out of the interior

and into its environment (i.e. the room). The refrigerant is used asthe medium which absorbs and removes heat from the space to becooled and subsequently rejects that heat elsewhere.

Circulating refrigerant vapor enters the compressor and iscompressed to a higher pressure, resulting in a higher temperature aswell. The hot, compressed refrigerant vapor is now at a temperatureand pressure at which it can be condensed and is routed through acondenser. Here it is cooled by air flowing across the condenser coils and condensed into a liquid. Thus, the circulating refrigerant

rejects heat from the system and the heat is carried away by the air.

The condensed and pressurized liquid refrigerant is next routedthrough an expansion valve where it undergoes an abrupt reductionin pressure. That pressure reduction results in flash evaporation of a

part of the liquid refrigerant, lowering its temperature. The coldrefrigerant is then routed through the evaporator. A fan blows thewarm air (which is to be cooled) across the evaporator, causing theliquid part of the cold refrigerant mixture to evaporate as well,further lowering the temperature. The warm air is therefore cooled.

To complete the refrigeration cycle, the refrigerant vapor is routed back into the compressor.

By placing the condenser inside a compartment, and the evaporator in the ambient environment (such as outside), or by merely runningan air conditioner's refrigerant in the opposite direction, the overalleffect is the opposite, and the compartment is heated instead of cooled. See also heat pump.

The engineering of physical and thermodynamic properties of gas–vapor mixtures is called psychrometrics

http://en.wikipedia.org/wiki/Psychrometricshttp://en.wikipedia.org/wiki/Thermal_expansion_valvehttp://en.wikipedia.org/wiki/Gas_compressorhttp://en.wikipedia.org/wiki/Heat_pumphttp://en.wikipedia.org/wiki/Frosthttp://en.wikipedia.org/wiki/Evaporator_coilhttp://en.wikipedia.org/wiki/Condensationhttp://en.wikipedia.org/wiki/Refrigeranthttp://en.wikipedia.org/wiki/Thermal_expansion_valvehttp://en.wikipedia.org/wiki/Condensing_coilhttp://en.wikipedia.org/wiki/File:Capilliary_metering_device.jpghttp://en.wikipedia.org/wiki/Flash_evaporationhttp://en.wikipedia.org/wiki/File:Heatpump.svghttp://en.wikipedia.org/wiki/Refrigeration_cyclehttp://en.wikipedia.org/wiki/Evaporator_coilhttp://en.wikipedia.org/wiki/Refrigeratorhttp://en.wikipedia.org/wiki/Gas_compressorhttp://en.wikipedia.org/wiki/Condenser_(heat_transfer)


7/20



Heat pump

Heat pump is a term for a type of air conditioner in which the refrigeration cycle can be reversed, producinheating instead of cooling in the indoor environment. They are also commonly referred to, and marketed aa "reverse cycle air conditioner". Using an air conditioner in this way to produce heat is significantly moreenergy efficient than electric resistance heating. Some homeowners elect to have a heat pump systeminstalled, which is simply a central air conditioner with heat pump functionality (the refrigeration cycle can

be reversed in cold weather). When the heat pump is in heating mode, the indoor evaporator coil switchesroles and becomes the condenser coil, producing heat. The outdoor condenser unit also switches roles toserve as the evaporator, and discharges cold air (colder than the ambient outdoor air).

Heat pumps are more popular in milder winter climates where the temperature is frequently in the range of40–55 °F (4–13 °C), because heat pumps become inefficient in more extreme cold. This is due to the

problem of ice forming on the outdoor unit's heat exchanger coil, which blocks air flow over the coil. Tocompensate for this, the heat pump system must temporarily switch back into the regular air conditioningmode to switch the outdoor evaporator coil back to being the condenser coil, so that it can heat up anddefrost. A heat pump system will therefore have a form of electric resistance heating in the indoor air paththat is activated only in this mode in order to compensate for the temporary indoor air cooling, which woul

otherwise be uncomfortable in the winter. The icing problem becomes much more severe with lower outdoor temperatures, so heat pumps are commonly installed in tandem with a more conventional form of heating, such as a natural gas or oil furnace, which is used instead of the heat pump during harsher winter temperatures. In this case, the heat pump is used efficiently during the milder temperatures, and the systemis switched to the conventional heat source when the outdoor temperature is lower.it also works on the basiof carnot cycle

Absorption heat pumps are actually a kind of air-source heat pump, but they do not depend on electricity to power them. Instead, gas, solar power, or heated water is used as a main power source. Additionally,refrigerant is not used at all in the process. An absorption pump absorbs ammonia into water. Next, the

water and ammonia mixture is depressurized to induce boiling, and the ammonia is boiled off, resulting incooling.[29]

Some more expensive window air conditioning units have a true heat pump function. However, a windowunit that has a "heat" selection is not necessarily a heat pump because some units use only electricresistance heat when heating is desired. A unit that has true heat pump functionality will be indicated itsspecifications by the term "heat pump".

Evaporative cooling

In very dry climates, evaporative coolers, sometimes referred to as swamp coolers or desert coolers, are popular for improving coolness during hot weather. An evaporative cooler is a device that draws outside athrough a wet pad, such as a large sponge soaked with water. The sensible heat of the incoming air, asmeasured by a dry bulb thermometer, is reduced. The total heat (sensible heat plus latent heat) of theentering air is unchanged. Some of the sensible heat of the entering air is converted to latent heat by theevaporation of water in the wet cooler pads. If the entering air is dry enough, the results can be quitecooling. Evaporative coolers tend to feel as if they are not working during times of high humidity, whenthere is not much dry air with which the coolers can work to make the air as cool as possible for dwellingoccupants. Unlike other types of air conditioners, evaporative coolers rely on the outside air to be channelethrough cooler pads that cool the air before it reaches the inside of a house through its air duct system; this

http://en.wikipedia.org/wiki/Sensible_heathttp://en.wikipedia.org/wiki/Refrigeration_cyclehttp://en.wikipedia.org/wiki/Furnacehttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/Heating_oilhttp://en.wikipedia.org/wiki/Dry-bulb_temperaturehttp://en.wikipedia.org/wiki/Sponge_(tool)http://en.wikipedia.org/wiki/Total_heathttp://en.wikipedia.org/wiki/Central_air_conditionerhttp://en.wikipedia.org/wiki/Electric_resistance_heating


8/20



An evaporative cooler

cooled outside air must be allowed to push the warmer air within the house out through an exhaust opening

such as an open door or window.[30] These coolers cost less and are mechanically simple to understand andmaintain.

An early type of cooler, using ice for a further effect, was patented by John Gorrie of Apalachicola, Floridain 1842. He used the device to cool the patients in his malaria hospital.

Free cooling

Air conditioning can also be provided by a process calledfree cooling which uses pumps to circulate a coolant(typically water or a glycol mix) from a cold source, whichin turn acts as a heat sink for the energy that is removedfrom the cooled space. Common storage media are deepaquifers or a natural underground rock mass accessed via acluster of small-diameter boreholes, equipped with heatexchanger. Some systems with small storage capacity arehybrid systems, using free cooling early in the coolingseason, and later employing a heat pump to chill thecirculation coming from the storage. The heat pump is added

because the temperature of the storage gradually increasesduring the cooling season, thereby declining itseffectiveness.

Free cooling systems can have very high efficiencies, and are sometimes combined with seasonal thermalenergy storage (STES) so the cold of winter can be used for summer air conditioning. Free cooling and

hybrid systems are mature technology.[31]

Humidity control

Since humans perspire to provide natural cooling by the evaporation of perspiration from the skin, drier air(up to a point) improves the comfort provided. The comfort air conditioner is designed to create a 40% to60% relative humidity in the occupied space.

Dehumidification and cooling

Refrigeration air conditioning equipment usually reduces the absolute humidity of the air processed by the

system. The relatively cold (below the dewpoint) evaporator coil condenses water vapor from the processeair, much like an ice-cold drink will condense water on the outside of a glass. Therefore, water vapor isremoved from the cooled air and the relative humidity in the room is lowered. The water is usually sent to drain or may simply drip onto the ground outdoors. The heat is rejected by the condenser which is locatedoutside of room to be cooled.

Dehumidification only

http://en.wikipedia.org/wiki/Evaporationhttp://en.wikipedia.org/wiki/Perspirationhttp://en.wikipedia.org/wiki/Mature_technologyhttp://en.wikipedia.org/wiki/Apalachicola,_Floridahttp://en.wikipedia.org/wiki/File:Evaporative_cooler,_CO,_IMG_5681.JPGhttp://en.wikipedia.org/wiki/John_Gorriehttp://en.wikipedia.org/wiki/Hospitalhttp://en.wikipedia.org/wiki/Free_coolinghttp://en.wikipedia.org/wiki/Patenthttp://en.wikipedia.org/wiki/Heat_sinkhttp://en.wikipedia.org/wiki/Dewpointhttp://en.wikipedia.org/wiki/Humidityhttp://en.wikipedia.org/wiki/Icehttp://en.wikipedia.org/wiki/Seasonal_thermal_energy_storagehttp://en.wikipedia.org/wiki/Malaria


9/20



Typical portable dehumidifier

An air conditioner that is used only for dehumidifying is called a dehumidifier. It also uses a refrigerationcycle, but differs from a "regular" air conditioner in that both theevaporator and the condenser are placed in the same air path. A"regular" air conditioner transfers heat energy out of the room

because its condenser coil is outside. However, since all componentsof the dehumidifier are in the same room, no heat energy isremoved. Instead, the electric power consumed by the dehumidifier remains in the room as heat, so the room is actually heated , just as

by an electric heater that draws the same amount of power. Inaddition, if the condensed water has been removed from the room,the amount of heat needed to boil that water has been added to theroom (the "latent heat of vaporization"). The dehumidification

process is the inverse of adding water to the room with anevaporative cooler, and instead releases heat.

Inside the unit, the air passes over the evaporator coil first and iscooled and dehumidified. The now dehumidified, cold air then

passes over the condenser coil where it is warmed up again. Then

the air is released back into the room. The unit produces warm,dehumidified air and can usually be placed freely in theenvironment (room) that is to be conditioned.

Dehumidifiers are commonly used in cold, damp climates to prevent mold growth indoors, especially in basements. They are also used to protect sensitive equipment from the adverse effects of excessivehumidity in tropical countries.

Energy transfer

In a thermodynamically closed system, any power dissipated into the system that is being maintained at aset temperature (which is a standard mode of operation for modern air conditioners) requires that the rate oenergy removal by the air conditioner increase. This increase has the effect that, for each unit of energyinput into the system (say to power a light bulb in the closed system), the air conditioner removes that

energy.[32] In order to do so, the air conditioner must increase its power consumption by the inverse of its"efficiency" (coefficient of performance) times the amount of power dissipated into the system. As anexample, assume that inside the closed system a 100 W heating element is activated, and the air conditionehas an coefficient of performance of 200%. The air conditioner's power consumption will increase by 50 Wto compensate for this, thus making the 100 W heating element cost a total of 150 W of power.

It is typical for air conditioners to operate at "efficiencies" of significantly greater than 100%. [33] Howeverit may be noted that the input electrical energy is of higher thermodynamic quality (lower entropy) than theoutput thermal energy (heat energy).

Air conditioner equipment power in the U.S. is often described in terms of "tons of refrigeration". A ton ofrefrigeration is approximately equal to the cooling power of one short ton (2000 pounds or 907 kilograms)

of ice melting in a 24-hour period. The value is defined as 12,000 BTU per hour, or 3517 watts. [34]

Residential central air systems are usually from 1 to 5 tons (3 to 20 kilowatts (kW)) in capacity.

http://en.wikipedia.org/wiki/Electric_heaterhttp://en.wikipedia.org/wiki/Dehumidifierhttp://en.wikipedia.org/wiki/Heating_elementhttp://en.wikipedia.org/wiki/Refrigeration_cyclehttp://en.wikipedia.org/wiki/BTUhttp://en.wikipedia.org/wiki/File:Maytag_dehumidifier1.jpghttp://en.wikipedia.org/wiki/Closed_systemhttp://en.wikipedia.org/wiki/Evaporative_coolerhttp://en.wikipedia.org/wiki/Entropyhttp://en.wikipedia.org/wiki/Ton_of_refrigerationhttp://en.wikipedia.org/wiki/Short_tonhttp://en.wikipedia.org/wiki/Watthttp://en.wikipedia.org/wiki/Enthalpy_of_vaporizationhttp://en.wikipedia.org/wiki/Coefficient_of_performancehttp://en.wikipedia.org/wiki/Mold


10/20



Seasonal energy efficiency ratio

For residential homes, some countries set minimum requirements for energy efficiency. In the UnitedStates, the efficiency of air conditioners is often (but not always) rated by the seasonal energy efficiencyratio (SEER). The higher the SEER rating, the more energy efficient is the air conditioner. The SEER ratinis the BTU of cooling output during its normal annual usage divided by the total electric energy input in

watt hours (W·h) during the same period.[35]

SEER = BTU ÷ (W·h)

this can also be rewritten as:

SEER = (BTU / h) ÷ W, where "W" is the average electrical power in Watts, and (BTU/h) is the

rated cooling power.

For example, a 5000 BTU/h air-conditioning unit, with a SEER of 10, would consume 5000/10 = 500 Watof power on average.

The electrical energy consumed per year can be calculated as the average power multiplied by the annualoperating time:

500 W × 1000 h = 500,000 W·h = 500 kWh

Assuming 1000 hours of operation during a typical cooling season (i.e., 8 hours per day for 125 days per ear).

Another method that yields the same result, is to calculate the total annual cooling output:

5000 BTU/h × 1000 h = 5,000,000 BTU

Then, for a SEER of 10, the annual electrical energy usage would be:

5,000,000 BTU ÷ 10 = 500,000 W·h = 500 kWh

SEER is related to the coefficient of performance (COP) commonly used in thermodynamics and also to thEnergy Efficiency Ratio (EER). The EER is the efficiency rating for the equipment at a particular pair of external and internal temperatures, while SEER is calculated over a whole range of external temperatures

(i.e., the temperature distribution for the geographical location of the SEER test). SEER is unusual in that iis composed of an Imperial unit divided by an SI unit. The COP is a ratio with the same metric units of energy (joules) in both the numerator and denominator. They cancel out, leaving a dimensionless quantity.Formulas for the approximate conversion between SEER and EER or COP are available from the Pacific

Gas and Electric Company:[36]

(1) SEER = EER ÷ 0.9

(2) SEER = COP × 3.792

(3) EER = COP × 3.413

http://en.wikipedia.org/wiki/Kilowatt_hourhttp://en.wikipedia.org/wiki/Energy_Efficiency_Ratiohttp://en.wikipedia.org/wiki/Joulehttp://en.wikipedia.org/wiki/Fraction_(mathematics)http://en.wikipedia.org/wiki/Imperial_unitshttp://en.wikipedia.org/wiki/Thermodynamicshttp://en.wikipedia.org/wiki/SI_unithttp://en.wikipedia.org/wiki/KWhhttp://en.wikipedia.org/wiki/Dimensionless_quantityhttp://en.wikipedia.org/wiki/Pacific_Gas_and_Electric_Companyhttp://en.wikipedia.org/wiki/Coefficient_of_performancehttp://en.wikipedia.org/wiki/Fraction_(mathematics)


11/20



Air conditioning window unit

Parts of a windows unit

From equation (2) above, a SEER of 13 is equivalent to a COP of 3.43, which means that 3.43 units of heaenergy are pumped per unit of work energy.

The United States now requires that residential systems manufactured in 2006 have a minimum SEER

rating of 13 (although window-box systems are exempt from this law, so their SEER is still around 10). [37

Installation types

Window unit and packaged terminal

Window unit air conditioners are installed in an open window. Theinterior air is cooled as a fan blows it over the evaporator. On theexterior the heat drawn from the interior is dissipated into theenvironment as a second fan blows outside air over the condenser. Alarge house or building may have several such units, permitting each

room to be cooled separately.[38]

PTAC systems are also known as wall-split air conditioning systemsor ductless systems.[39] These PTAC systems which are frequentlyused in hotels have two separate units (terminal packages), theevaporative unit on the interior and the condensing unit on theexterior, with an opening passing through the wall and connectingthem. This minimizes the interior system footprint and allows eachroom to be adjusted independently. PTAC systems may be adaptedto provide heating in cold weather, either directly by using anelectric strip, gas, or other heater, or by reversing the refrigerantflow to heat the interior and draw heat from the exterior air,

converting the air conditioner into a heat pump. While room air conditioning provides maximum flexibility, when used to cool manyrooms at a time it is generally more expensive than central air conditioning.

The first practical through-the-wall air conditioning unit was

invented by engineers at Chrysler Motors and offered for sale starting in 1935.[40]

Split systems

Split-system air conditioners come in two forms: mini-split and central systems. In both types, the inside-environment (evaporative) heat exchanger is separated by some distance from the outside-environment(condensing unit) heat exchanger.

Mini-split (ductless) system

A mini-split system typically supplies chilled air to a single or a few rooms of a building.[41] Mini-split

systems typically produce 9,000–36,000 Btu (9,500–38,000 kJ) per hour of cooling.[42]

http://en.wikipedia.org/wiki/File:Condicionadordear.jpghttp://en.wikipedia.org/wiki/File:Air_conditioning_unit-en.svghttp://en.wikipedia.org/wiki/Packaged_terminal_air_conditionerhttp://en.wikipedia.org/wiki/Heat_exchangerhttp://en.wikipedia.org/wiki/Chrysler_Motors


12/20



Outside part of a ductless split-type

air conditioner

Indoor part of a ductless split-type air

conditioner

Advantages of the ductless system include smaller size and flexibility for zoning or heating and coolingindividual rooms. The inside wall space required is significantly reduced. Also, the compressor and heatexchanger can be located further away from the inside space, rather than merely on the other side of thesame unit as in a PTAC or window air conditioner. Flexible exterior hoses lead from the outside unit to the interior one(s); these areoften enclosed with metal to look like common drainpipes from theroof. In addition, ductless systems offer higher efficiency (up to 27.1SEER on some systems).

The primary disadvantage of ductless air conditioners is their cost.Such systems cost about $1,500 to $2,000 per ton (12,000 Btu per hour) of cooling capacity. This is about 30% more than centralsystems (not including ductwork) and may cost more than twice as

much as window units of similar capacity."[43]

An additional possible disadvantage that may increase net cost isthat ductless systems may sometimes not be eligible for energyefficiency rebates offered by many electric utility companies as part

of an incentive program to reduce summer cooling load on theelectrical grid.[44]

Central (ducted) air conditioning

Central (ducted) air conditioning offers whole-house or large-commercial-space cooling, and often offers moderate multi-zonetemperature control capability by the addition of air-louver-control

boxes.

In central air conditioning, the inside heat-exchanger is typically placed inside the central furnace/AC unitof the forced air heating system which is then used in the summer to distribute chilled air throughout aresidence or commercial building.

Portable units

A portable air conditioner can be easily transported inside a home or office. They are currently availablewith capacities of about 5,000–60,000 BTU/h (1,800–18,000 W output) and with or without electric-resistance heaters. Portable air conditioners are either evaporative or refrigerative.

The compressor-based refrigerant systems are air-cooled, meaning they use air to exchange heat, in thesame way as a car or typical household air conditioner does. Such a system dehumidifies the air as it coolsit. It collects water condensed from the cooled air and produces hot air which must be vented outside thecooled area; doing so transfers heat from the air in the cooled area to the outside air.

Portable split system

A portable split system has an indoor unit on wheels connected to an outdoor unit via flexible pipes, similato a permanently fixed installed unit.

http://en.wikipedia.org/wiki/Energy_rebate_programhttp://en.wikipedia.org/wiki/Central_heatinghttp://en.wikipedia.org/wiki/BTUhttp://en.wikipedia.org/wiki/File:Splitklimaanlage_IMGP9925_unbranded.jpghttp://en.wikipedia.org/wiki/Forced-airhttp://en.wikipedia.org/wiki/File:Galanz_Air_Conditioner_2.jpghttp://en.wikipedia.org/wiki/Duct_(HVAC)http://en.wikipedia.org/wiki/Electrical_gridhttp://en.wikipedia.org/wiki/Electric_utility


13/20



Portable hose system

Hose systems, which can be monoblock or air-to-air , are vented to the outside via air ducts. The monobloctype collects the water in a bucket or tray and stops when full. The air-to-air type re-evaporates the water and discharges it through the ducted hose and can run continuously.

A single-hose unit uses air from within the room to cool its condenser, and then vents it outside. This air isreplaced by hot air from outside or other rooms (due to the negative pressure inside the room), thus

reducing the unit's effectiveness.[45]

Modern units might have a coefficient of performance of approximately 3 (i.e., 1 kW of electricity will produce 3 kW of cooling). A dual-hose unit draws air to cool its condenser from outside instead of frominside the room, and thus is more effective than most single-hose units.

Portable evaporative system

Evaporative coolers, sometimes called "swamp coolers", do not have a compressor or condenser. Liquidwater is evaporated on the cooling fins, releasing the vapor into the cooled area. Evaporating water absorbsa significant amount of heat, the latent heat of vaporisation, cooling the air. Humans and animals use thesame mechanism to cool themselves by sweating.

Evaporative coolers have the advantage of needing no hoses to vent heat outside the cooled area, makingthem truly portable. They are also very cheap to install and use less energy than refrigerative air conditioners.

Uses

Air-conditioning engineers broadly divide air conditioning applications into comfort and processapplications.

Comfort applications

Comfort applications aim to provide a building indoor environment that remains relatively constant despitechanges in external weather conditions or in internal heat loads.

Air conditioning makes deep plan buildings feasible, for otherwise they would have to be built narrower orwith light wells so that inner spaces received sufficient outdoor air via natural ventilation. Air conditioning

also allows buildings to be taller, since wind speed increases significantly with altitude making naturalventilation impractical for very tall buildings. Comfort applications are quite different for various buildingtypes and may be categorized as:

Commercial buildings, which are built for commerce, including offices, malls, shopping centers,

restaurants, etc.

High-rise residential buildings, such as tall dormitories and apartment blocks

Industrial spaces where thermal comfort of workers is desired

Institutional buildings, which includes government buildings, hospitals, schools, etc.

http://en.wikipedia.org/wiki/Enthalpy_of_vaporizationhttp://en.wikipedia.org/wiki/Coefficient_of_performancehttp://en.wikipedia.org/wiki/Evaporative_coolerhttp://en.wikipedia.org/wiki/Building_sciencehttp://en.wikipedia.org/wiki/Wind_gradienthttp://en.wikipedia.org/wiki/Light_wellhttp://en.wikipedia.org/wiki/Duct_(HVAC)http://en.wikipedia.org/wiki/Natural_ventilationhttp://en.wikipedia.org/wiki/Deep_planhttp://en.wikipedia.org/wiki/Perspiration


14/20



Low-rise residential buildings, including single-family houses, duplexes, and small apartment

buildings

Sports stadiums, such as the University of Phoenix Stadium[46] and in Qatar for the 2022 FIFA Worl

Cup.[47]

The structural impact of an air conditioning unit will depend on the type and size of the unit.[48]

In addition to buildings, air conditioning can be used for many types of transportation, includingautomobiles, buses and other land vehicles, trains, ships, aircraft, and spacecraft.

Domestic use

Air conditioning is common in the US, with 88% of new single-family homes constructed in 2011 includin

air conditioning, ranging from 99% in the South to 62% in the West. [49] In Europe, home air conditioning generally less common. Southern European countries such as Greece have seen a wide proliferation of

home air-conditioning units in recent years.[50] In another southern European country, Malta, it is estimate

that around 55% of households have an air conditioner installed.[51] In India AC sales have dropped by 40%

due to higher costs and stricter energy efficiency regulations.[52]

Process applications

Process applications aim to provide a suitable environment for a process being carried out, regardless of internal heat and humidity loads and external weather conditions. It is the needs of the process thatdetermine conditions, not human preference. Process applications include these:

Chemical and biological laboratoriesCleanrooms for the production of integrated circuits, pharmaceuticals, and the like, in which very

high levels of air cleanliness and control of temperature and humidity are required for the success of

the process.

Environmental control of data centers

Facilities for breeding laboratory animals. Since many animals normally reproduce only in spring,

holding them in rooms in which conditions mirror those of spring all year can cause them to

reproduce year-round.

Food cooking and processing areas

Hospital operating theatres, in which air is filtered to high levels to reduce infection risk and the

humidity controlled to limit patient dehydration. Although temperatures are often in the comfort

range, some specialist procedures, such as open heart surgery, require low temperatures (about 18 °C

64 °F) and others, such as neonatal, relatively high temperatures (about 28 °C, 82 °F).

Industrial environments

Mining

http://en.wikipedia.org/wiki/Data_centershttp://en.wikipedia.org/wiki/Operating_theatrehttp://en.wikipedia.org/wiki/Cardiac_surgeryhttp://en.wikipedia.org/wiki/Single-family_homeshttp://en.wikipedia.org/wiki/Maltahttp://en.wikipedia.org/wiki/Spring_(season)http://en.wikipedia.org/wiki/Biologyhttp://en.wikipedia.org/wiki/Neonatalhttp://en.wikipedia.org/wiki/Data_center_environmental_controlhttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/Industrial_ecologyhttp://en.wikipedia.org/wiki/Greecehttp://en.wikipedia.org/wiki/Food_processinghttp://en.wikipedia.org/wiki/Laboratory_animalhttp://en.wikipedia.org/wiki/Southern_Europehttp://en.wikipedia.org/wiki/University_of_Phoenix_Stadiumhttp://en.wikipedia.org/wiki/Qatar_2022_FIFA_World_Cup_bidhttp://en.wikipedia.org/wiki/Cleanroomhttp://en.wikipedia.org/wiki/Laboratoryhttp://en.wikipedia.org/wiki/Pharmaceuticalshttp://en.wikipedia.org/wiki/Western_United_Stateshttp://en.wikipedia.org/wiki/Cookinghttp://en.wikipedia.org/wiki/Mininghttp://en.wikipedia.org/wiki/Southern_United_Stateshttp://en.wikipedia.org/wiki/Infectionhttp://en.wikipedia.org/wiki/Chemistry


15/20



Nuclear power facilities

Physical testing facilities

Plants and farm growing areas

Textile manufacturing

In both comfort and process applications, the objective may be to not only control temperature, but alsohumidity, air quality, and air movement from space to space.

Health issues

Air-conditioning systems can promote the growth and spread of microorganisms,[53] such as Legionellaneumophila, the infectious agent responsible for Legionnaires' disease, or thermophilic actinomycetes;

however, this is only prevalent in poorly maintained water cooling towers. As long as the cooling tower iskept clean (usually by means of a chlorine treatment), these health hazards can be avoided.

Conversely, air conditioning (including filtration, humidification, cooling and disinfection) can be used to

provide a clean, safe, hypoallergenic atmosphere in hospital operating rooms and other environments wheran appropriate atmosphere is critical to patient safety and well-being. Excessive air conditioning can have

negative effect on skin, drying it out,[54] and can also cause dehydration.[55]

Environmental impact

Power consumption

Innovation in air conditioning technologies continues, with much recent emphasis placed on energy

efficiency. Production of the electricity used to operate air conditioners has an environmental impact,including the release of greenhouse gasses.

Cylinder unloaders are a method of load control used mainly in commercial air conditioning systems. On asemi-hermetic (or open) compressor, the heads can be fitted with unloaders which remove a portion of theload from the compressor so that it can run better when full cooling is not needed. Unloaders can beelectrical or mechanical.

In an automobile, the A/C system will use around 4 horsepower (3 kW) of the engine's power, thus

increasing fuel consumption of the vehicle.[56]

Refrigerants

Most refrigerants used for air conditioning contribute to global warming, and many also deplete the ozone

layer.[57] CFCs, HCFCs, and HFCs are potent greenhouse gases when leaked to the atmosphere.

The use of Chlorofluorocarbon (CFC) as a refrigerant was once common, being used in the refrigerants R-11 and R-12 and R 134 (sold under the brand name Freon-12). Freon refrigerants were commonly usedduring the 20th century in air conditioners due to their superior stability and safety properties. However,

these chlorine-bearing refrigerants reach the upper atmosphere when they escape.[58] Once the refrigerant

http://en.wikipedia.org/wiki/Trichlorofluoromethanehttp://en.wikipedia.org/wiki/Legionella_pneumophilahttp://en.wikipedia.org/wiki/Ozone_depletionhttp://en.wikipedia.org/wiki/Hydrofluorocarbonhttp://en.wikipedia.org/wiki/Hermetic_sealhttp://en.wikipedia.org/wiki/Hydrochlorofluorocarbonhttp://en.wikipedia.org/wiki/Actinomyceteshttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Dichlorodifluoromethanehttp://en.wikipedia.org/wiki/Horsepowerhttp://en.wikipedia.org/wiki/Chlorofluorocarbonhttp://en.wikipedia.org/wiki/Legionellosishttp://en.wikipedia.org/wiki/Greenhouse_gaseshttp://en.wikipedia.org/wiki/Hypoallergenichttp://en.wikipedia.org/wiki/Chlorofluorocarbonhttp://en.wikipedia.org/wiki/Power_(physics)http://en.wikipedia.org/wiki/Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Textile_manufacturinghttp://en.wikipedia.org/wiki/Dehydrationhttp://en.wikipedia.org/wiki/Freonhttp://en.wikipedia.org/wiki/Humidityhttp://en.wikipedia.org/wiki/Nuclear_power


16/20



reaches the stratosphere, UV radiation from the Sun homolytically cleaves the chlorine-carbon bond,ielding a chlorine radical. These chlorine atoms catalyze the breakdown of ozone into diatomic oxygen,

depleting the ozone layer that shields the Earth's surface from strong UV radiation. Each chlorine radicalremains active as a catalyst unless it binds with another chlorine radical, forming a stable molecule and

breaking the chain reaction.

Prior to 1994, most automotive air conditioning systems used R-12 as a refrigerant. It was replaced with R134a refrigerant, which has a lower ozone depletion potential. Old R-12 systems can be retrofitted to R-

134a by a complete flush and filter/dryer replacement to remove the mineral oil, which is not compatiblewith R-134a.

R-22 (also known as HCFC-22) has a global warming potential about 1,800 times higher than CO2.[59] It

was to be phased out for use in new equipment by 2010, and is to be completely discontinued by 2020.Although those gasses can be recycled when air conditioning units are disposed of, uncontrolled dumpingand leaking can accidentally release those gas directly in the atmosphere.

In most countries the manufacture and use of CFCs has been banned or severely restricted due to concerns

about ozone depletion (see also Montreal Protocol).

[60]

In light of these environmental concerns, beginningon November 14, 1994, the U.S. Environmental Protection Agency has restricted the sale, possession and

use of refrigerant to only licensed technicians, per Rules 608 and 609 of the EPA rules and regulations. [61]

As an alternative to conventional refrigerants, natural gases, such as CO2 (R-744), have been proposed.[62]

R-744 is being adopted as a refrigerant in Europe and Japan. It is an effective refrigerant with a globalwarming potential of 1, but it must use higher compression to produce an equivalent cooling effect.

In fact, in 1992, a non-governmental organization was spurred by corporate executive policies andrequested that a European lab find a substitute. The result quickly led to two alternative mixes, one of

propane (R290) and isobutane (R60Oa), and one of pure isobutane.[18][21] Corporate executives resistedchange in Europe only until 1993, but in the U.S. until 2011, despite some supportive steps in 2004 and

2008 (see Refrigerant Development above).[28][63]

See also

Cassette air conditioner

Crankcase heater

Energy labelHydronics

Ground-coupled heat exchanger

Ice storage air conditioning

Inverter (air conditioning)

List of home appliances

Louver

Ozone Depletion

http://en.wikipedia.org/wiki/R-744http://en.wikipedia.org/wiki/Crankcase_heaterhttp://en.wikipedia.org/wiki/Chlorodifluoromethanehttp://en.wikipedia.org/wiki/Diatomichttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Montreal_Protocolhttp://en.wikipedia.org/wiki/Moleculehttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Chain_reactionhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/R-134ahttp://en.wikipedia.org/wiki/Federal_government_of_the_United_Stateshttp://en.wikipedia.org/wiki/Inverter_(air_conditioning)http://en.wikipedia.org/wiki/Radical_(chemistry)http://en.wikipedia.org/wiki/Global_warming_potentialhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Catalysthttp://en.wikipedia.org/wiki/European_Union_energy_label#Air_conditionershttp://en.wikipedia.org/wiki/Homolysis_(chemistry)http://en.wikipedia.org/wiki/Ozone_layerhttp://en.wikipedia.org/wiki/Hydronicshttp://en.wikipedia.org/wiki/Louverhttp://en.wiktionary.org/wiki/cassette_air_conditionerhttp://en.wikipedia.org/wiki/Ice_storage_air_conditioninghttp://en.wikipedia.org/wiki/Ground-coupled_heat_exchangerhttp://en.wikipedia.org/wiki/Chemical_bondhttp://en.wikipedia.org/wiki/Ultraviolethttp://en.wikipedia.org/wiki/Seasonal_thermal_energy_storagehttp://en.wikipedia.org/wiki/Ozone_Depletionhttp://en.wikipedia.org/wiki/Stratospherehttp://en.wikipedia.org/wiki/List_of_home_applianceshttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Global_warming_potentialhttp://en.wikipedia.org/wiki/Ozone_depletion_potential


17/20

12/1/2014 Air conditioning - Wi kipedia, the free encyclopedia


References

easona erma energy s orage

Seawater air conditioning

1. ^ Daou, K; Wang, Xia (2005). "Desiccant cooling air conditioning: a review"

(http://www.sciencedirect.com/science/article/pii/S1364032104001200). Renewable and Sustainable Energy

Reviews 10 (2): 55–77.

2. ^ McDowall, Robert (2006). Fundamentals of HVAC Systems. Elsevier. p. 3. ISBN 9780080552330.

3. ^ Bahadori MN (February 1978). "Passive Cooling Systems in Iranian Architecture". Scientific American 238

(2): 144–154. doi:10.1038/scientificamerican0278-144 (http://dx.doi.org/10.1038%2Fscientificamerican0278-

144).

4. ^ Needham, Joseph (1991). Science and Civilisation in China, Volume 4: Physics and Physical Technology, Pa

2, Mechanical Engineering . Cambridge University Press. pp. 99, 151, 233. ISBN 978-0-521-05803-2.

5. ^ Needham, Joseph (1991). Science and Civilisation in China, Volume 4: Physics and Physical Technology, Pa

2, Mechanical Engineering . Cambridge University Press. pp. 134, 151. ISBN 978-0-521-05803-2.

6. ^ Laszlo, Pierre (June 2001). Salt: Grain of Life (http://books.google.com/?

id=DhhN_FthpYMC&pg=PA117&dq=Cornelius+Drebbel+%22air+conditioning%22). ISBN 978-0-231-12198-

7. ^ Franklin, Benjamin (June 17, 1758). "Letter to John Lining"

(http://www.waughfamily.ca/Montgomery/benfranklin1758.htm). Retrieved 6 August 2014.

8. ^ History of Air Conditioning (http://bergenrefrigeration.wordpress.com/2014/08/30/history-of-air-conditioning

9. ^ The History of Air Conditioning (http://furnace-repair-edmonton.ca/history-air-conditioning/) Furnace Repair

Edmonton, 2014

10. ^ Patent 8080 (http://www.google.com/patents/US8080) at Google Patents11. ^ Nagengast, Bernard (February 1999). "A History of Comfort Cooling Using Ice"

(http://www.ashrae.org/File%20Library/docLib/Public/200362710047_326.pdf). ASHRAE Journal : 49. Retrieve

July 2013.

12. ^ "Famous Geelong people - James Harrison" (http://www.geelong.ws/Famous-Geelong-People/James-

Harrison.html). Retrieved 6 August 2014.

13. ^ "Early University Benefactors" (http://www.rizzoconferencecenter.com/PDFs/History-of-Meadowmont.pdf).

Rizzoconferencecenter.com. Retrieved 2012-11-08.

14. ^ http://navlog.org/patent_1.html

15. ^ Mate, John “Making a Difference: A Case Study of the Greenpeace Ozone Campaign” RECIEL 10:2 2001.16. ^ Benedick, Richard Elliot Ozone Diplomacy Cambridge, MA: Harvard University 1991.

17. ^ a b http://www.greenpeace.org/international/en/news/Blogs/makingwaves/happy-birthday-

greenfreeze/blog/44473/

18. ^ a b http://ozone.unep.org/Events/4C1_PublicInfo_Awards97.shtml

19. ^ in Spanish: http://ilustrados.com/tema/3015/Historia-Greenfreeze.html

20. ^ a b in Portuguese: http://www.greenpeace.org/brasil/pt/Noticias/discurso-de-frank-guggenheim-n/

21. ^ a b c http://www.ecomall.com/greenshopping/greenfreeze.htm

^ - - - - -

https://www.greenpeace.de/themen/klimawandel/klimaschutz/der-greenfreeze-endlich-den-usa-angekommenhttp://dx.doi.org/10.1038%2Fscientificamerican0278-144http://navlog.org/patent_1.htmlhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://www.ecomall.com/greenshopping/greenfreeze.htmhttp://furnace-repair-edmonton.ca/history-air-conditioning/http://ilustrados.com/tema/3015/Historia-Greenfreeze.htmlhttp://en.wikipedia.org/wiki/Special:BookSources/9780080552330http://www.rizzoconferencecenter.com/PDFs/History-of-Meadowmont.pdfhttp://www.google.com/patents/US8080http://en.wikipedia.org/wiki/Special:BookSources/978-0-231-12198-9http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/978-0-521-05803-2http://www.sciencedirect.com/science/article/pii/S1364032104001200http://en.wikipedia.org/wiki/Digital_object_identifierhttp://books.google.com/?id=DhhN_FthpYMC&pg=PA117&dq=Cornelius+Drebbel+%22air+conditioning%22http://www.geelong.ws/Famous-Geelong-People/James-Harrison.htmlhttp://ozone.unep.org/Events/4C1_PublicInfo_Awards97.shtmlhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/978-0-521-05803-2http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://www.waughfamily.ca/Montgomery/benfranklin1758.htmhttps://www.greenpeace.de/themen/klimawandel/klimaschutz/der-greenfreeze-endlich-den-usa-angekommenhttp://bergenrefrigeration.wordpress.com/2014/08/30/history-of-air-conditioning/http://www.ashrae.org/File%20Library/docLib/Public/200362710047_326.pdfhttp://en.wikipedia.org/wiki/Seasonal_thermal_energy_storagehttp://www.greenpeace.org/international/en/news/Blogs/makingwaves/happy-birthday-greenfreeze/blog/44473/http://en.wikipedia.org/wiki/Seawater_air_conditioninghttp://www.greenpeace.org/brasil/pt/Noticias/discurso-de-frank-guggenheim-n/


18/20

12/1/2014 Air conditioning - Wi kipedia, the free encyclopedia


. . .

angekommen

23. ^ http://www.refrigerantsnaturally.com/about-us/history-and-achievements.htm

24. ^ http://phx.corporate-ir.net/phoenix.zhtml?c=78265&p=irol-newsArticle&ID=1270984&highlight=

25. ^ http://www.nbcnewyork.com/news/green/Climate-Friendly_Greenfreezers_Come_to_the_United_States.html

26. ^ http://www.genewscenter.com/content/detail.aspx?releaseid=4303&newsareaid=2&menusearchcategoryid=

27. ^ http://www.greenpeace.org/usa/en/campaigns/global-warming-and-energy/green-solutions/greenfreeze/

28. ^a

b

see “Final Rule 17 (Dec. 20, 2011)” http://www.epa.gov/ozone/snap/chron.html29. ^ "Common Heat Pumps" (http://www.thomasnet.com/articles/pumps-valves-accessories/heat-pumps-common)

Thomasnet.com. Retrieved 2010-08-09.

30. ^ Shane Smith (2000). Greenhouse gardener's companion: growing food and flowers in your greenhouse or

sunspace (http://books.google.com/?id=Onv60-c6iEIC&pg=PA62&dq=evaporative-

cooler+exhaust+open+door+window&q=evaporative-cooler%20exhaust%20open%20door%20window) (2nd ed.

Fulcrum Publishing. p. 62. ISBN 978-1-55591-450-9.

31. ^ Snijders A. (2008). ATES Technology Development and Major Applications in Europe

(http://trca.on.ca/dotAsset/16551.pdf). Conservation for the Living Community Workshop (Toronto and Region

Conservation Authority).

32. ^ Jan F. Kreider. Handbook of heating, ventilation, and air conditioning . CRC press. ISBN 0-8493-9584-4.

33. ^ Winnick, J (1996). Chemical engineering thermodynamics. John Wiley and Sons. ISBN 0-471-05590-5.

34. ^ "NIST Guide to the SI" (http://physics.nist.gov/Pubs/SP811/appenB9.html). National Institute of Standards an

Technology. Archived

(http://web.archive.org/web/20070528005956/http://physics.nist.gov/Pubs/SP811/appenB9.html) from the origin

on 28 May 2007. Retrieved 2007-05-18.

35. ^ "Energy Glossary – S" (http://www.eia.gov/tools/glossary/index.cfm?id=S). Energy Glossary. Energy

Information Administration. Retrieved 2006-07-02.

36. ^ SEER conversion formulas from Pacific Gas and Electric

(http://web.archive.org/web/20071202130510/http://www.pge.com/docs/pdfs/biz/rebates/spc_contracts/2004_ma

uals_forms/spc_cooling_units.pdf). Web.archive.org (2007-12-02). Retrieved on 2012-01-09.

37. ^ "SEER" (http://www.energy.gov/news/3097.htm). United States Department of Energy. 2006-01-23. Retrieve

2006-07-02.

38. ^ Laboratory Performance Testing of Residential Window Air Conditioners (http://purl.fdlp.gov/GPO/gpo4161

National Renewable Energy Laboratory

39. ^ "Air Conditioning Explained" (http://benignblog.com/2012/01/how-air-conditioner-works-simple-

diagrammatic-explanation.html).40. ^ Hearst Magazines (June 1935). Popular Mechanics (http://books.google.com/books?

id=uN4DAAAAMBAJ&pg=PA885). Hearst Magazines. pp. 885–. ISSN 0032-4558

(https://www.worldcat.org/issn/0032-4558). Retrieved 9 January 2012.

41. ^ Mitsubishi Contractors Guide (http://www.mitsubishipro.com/media/382145/m-series_revised_july13.pdf) p.

42. ^ Mini-Split Systems

(http://www.goodmanmfg.com/ResidentialProducts/MiniSplitSystems/tabid/2072/Default.aspx)

43. ^ "Ductless Mini-Split Air Conditioners" (http://energy.gov/energysaver/articles/ductless-mini-split-air-

conditioners). US Department of Energy. 2012-08-09. Retrieved 2013-06-14.

http://www.xcelenergy.com/staticfiles/xe/Marketing/CO-Res-HE-Cooling-Info-Sheet.http://www.worldcat.org/issn/0032-4558http://www.nbcnewyork.com/news/green/Climate-Friendly_Greenfreezers_Come_to_the_United_States.htmlhttp://www.greenpeace.org/usa/en/campaigns/global-warming-and-energy/green-solutions/greenfreeze/http://web.archive.org/web/20071202130510/http://www.pge.com/docs/pdfs/biz/rebates/spc_contracts/2004_manuals_forms/spc_cooling_units.pdfhttp://trca.on.ca/dotAsset/16551.pdfhttp://en.wikipedia.org/wiki/Energy_Information_Administrationhttp://www.thomasnet.com/articles/pumps-valves-accessories/heat-pumps-commonhttp://www.xcelenergy.com/staticfiles/xe/Marketing/CO-Res-HE-Cooling-Info-Sheet.http://en.wikipedia.org/wiki/Special:BookSources/0-8493-9584-4http://phx.corporate-ir.net/phoenix.zhtml?c=78265&p=irol-newsArticle&ID=1270984&highlight=http://web.archive.org/web/20070528005956/http://physics.nist.gov/Pubs/SP811/appenB9.htmlhttp://energy.gov/energysaver/articles/ductless-mini-split-air-conditionershttp://books.google.com/?id=Onv60-c6iEIC&pg=PA62&dq=evaporative-cooler+exhaust+open+door+window&q=evaporative-cooler%20exhaust%20open%20door%20windowhttp://en.wikipedia.org/wiki/National_Institute_of_Standards_and_Technologyhttp://www.epa.gov/ozone/snap/chron.htmlhttp://www.eia.gov/tools/glossary/index.cfm?id=Shttp://www.mitsubishipro.com/media/382145/m-series_revised_july13.pdfhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://www.genewscenter.com/content/detail.aspx?releaseid=4303&newsareaid=2&menusearchcategoryid=http://en.wikipedia.org/wiki/International_Standard_Serial_Numberhttp://www.energy.gov/news/3097.htmhttp://benignblog.com/2012/01/how-air-conditioner-works-simple-diagrammatic-explanation.htmlhttp://books.google.com/books?id=uN4DAAAAMBAJ&pg=PA885http://en.wikipedia.org/wiki/Special:BookSources/0-471-05590-5http://physics.nist.gov/Pubs/SP811/appenB9.htmlhttp://en.wikipedia.org/wiki/Special:BookSources/978-1-55591-450-9http://en.wikipedia.org/wiki/National_Renewable_Energy_Laboratoryhttps://www.greenpeace.de/themen/klimawandel/klimaschutz/der-greenfreeze-endlich-den-usa-angekommenhttp://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://www.goodmanmfg.com/ResidentialProducts/MiniSplitSystems/tabid/2072/Default.aspxhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://purl.fdlp.gov/GPO/gpo41611http://www.refrigerantsnaturally.com/about-us/history-and-achievements.htm


19/20



44. ^ "2013 High Efficiency Cooling Rebate" (http://www.xcelenergy.com/staticfiles/xe/Marketing/CO-Res-HE-

Cooling-Info-Sheet.). Xcel Energy. Retrieved 2013-06-19.

45. ^ What is the difference between a single hose design and a dual hose design?

(http://www.experts123.com/q/what-is-the-difference-between-a-single-hose-design-and-a-dual-hose-

design.html). Experts123.com. Retrieved on 2012-01-09.

46. ^ "Qatar promises air-conditioned World Cup" (http://edition.cnn.com/2010/SPORT/12/03/qatar.world.cup/).

CNN . 2010-12-03.

47. ^ "BBC World Service - News - Qatar 2022: How to build comfortable stadiums in a hot climate"

(http://www.bbc.co.uk/worldservice/news/2010/12/101203_qatar_wt_sl.shtml). Bbc.co.uk. 2010-12-03. Retrieve

2012-11-08.

48. ^ Oakland Air Conditioning. "Structural Impact of Air Conditioning Installation"

(http://www.oaklandgroup.com/articles/index.php/air-conditioning/structural-impact-air-conditioning-

installation.html). Retrieved 2012-01-23.

49. ^ Characteristics of New Housing (http://www.census.gov/construction/chars/highlights.html)

50. ^ " "Χρυσές" δουλειές για τις εταιρείες κλιματιστικών έφερε το κύμα καύσωνα"

(http://news.in.gr/greece/article/?aid=819799&lngDtrID=244) (in Greek). Athens: Lambrakis Press. 2007-07-25

Retrieved 2008-06-30.

51. ^ "STĦARRIĠ DWAR ID-DĦUL U L-INFIQ TAL-FAMILJA 2008 /HOUSEHOLD BUDGETARY SURVEY

2008" (http://www.nso.gov.mt/docs/HBS2008.pdf). National Statistics Office, Maltz . Retrieved 2011-07-14.

52. ^ "High prices see air-conditioners' sales plunging 40% this summer"

(http://timesofindia.indiatimes.com/business/india-business/High-prices-see-air-conditioners-sales-plunging-40-

this-summer/articleshow/13659722.cms). Timesofindia.indiatimes.com. Retrieved 30 May 2012.

53. ^ "Negative Health Effects of Central AC"

(http://web.archive.org/web/20130128044033/http://www.livestrong.com/article/160205-negative-health-effects-

of-central-air-conditioning/). livestrong.com. Archived from the original(http://www.livestrong.com/article/160205-negative-health-effects-of-central-air-conditioning/) on 28 Jan 2013.

Retrieved 21 February 2013.

54. ^ "What your skin is telling you | Mail Online" (http://www.dailymail.co.uk/health/article-56595/What-skin-

telling-you.html). Dailymail.co.uk. 2001-06-28. Retrieved 2012-11-08.

55. ^ "Is your office killing you? | Mail Online" (http://www.dailymail.co.uk/health/article-443493/Is-office-killing-

you.html). Dailymail.co.uk. 2007-03-20. Retrieved 2012-11-08.

56. ^ "Impact of Vehicle Air-Conditioning on Fuel Economy" (http://www.nrel.gov/docs/fy00osti/28960.pdf).

National Renewable Energy Laboratory. Retrieved 6 February 2012.

57. ^ "Refrigerant Management Program Refrigerants Regulated"(http://www.arb.ca.gov/cc/reftrack/reftrackrefrigerants.htm). Californial Environmental Protection Agency.

Retrieved 22 April 2014.

58. ^ Chemicals in the environment: Freon 113 (http://www.epa.gov/chemfact/f_freon.txt). Retrieved on 2012-01-09

59. ^ "Chapter.2_FINAL.indd" (http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf) (PDF).

Retrieved 2010-08-09.

60. ^ CFC worldwide ban (http://www.sciencedaily.com/releases/2003/07/030730080139.htm). Sciencedaily.com

(2003-07-30). Retrieved on 2012-01-09.

61. ^ EPA Rules & Regulations restricting refrigerant (http://www.epa.gov/ozone/title6/608/608fact.html). Epa.gov

http://www.xcelenergy.com/staticfiles/xe/Marketing/CO-Res-HE-Cooling-Info-Sheet.http://www.bbc.co.uk/worldservice/news/2010/12/101203_qatar_wt_sl.shtmlhttp://www.census.gov/construction/chars/highlights.htmlhttp://www.epa.gov/ozone/title6/608/608fact.htmlhttp://www.dailymail.co.uk/health/article-56595/What-skin-telling-you.htmlhttp://www.epa.gov/chemfact/f_freon.txthttp://www.nso.gov.mt/docs/HBS2008.pdfhttp://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdfhttp://www.nrel.gov/docs/fy00osti/28960.pdfhttp://www.arb.ca.gov/cc/reftrack/reftrackrefrigerants.htmhttp://timesofindia.indiatimes.com/business/india-business/High-prices-see-air-conditioners-sales-plunging-40-this-summer/articleshow/13659722.cmshttp://news.in.gr/greece/article/?aid=819799&lngDtrID=244http://www.livestrong.com/article/160205-negative-health-effects-of-central-air-conditioning/http://www.oaklandgroup.com/articles/index.php/air-conditioning/structural-impact-air-conditioning-installation.htmlhttp://en.wikipedia.org/wiki/Athenshttp://web.archive.org/web/20130128044033/http://www.livestrong.com/article/160205-negative-health-effects-of-central-air-conditioning/http://www.sciencedaily.com/releases/2003/07/030730080139.htmhttp://en.wikipedia.org/wiki/Lambrakis_Presshttp://en.wikipedia.org/wiki/Greek_languagehttp://www.experts123.com/q/what-is-the-difference-between-a-single-hose-design-and-a-dual-hose-design.htmlhttp://edition.cnn.com/2010/SPORT/12/03/qatar.world.cup/http://www.dailymail.co.uk/health/article-443493/Is-office-killing-you.html


20/20


External links

Media related to Air conditioners at Wikimedia Commons

Retrieved from "http://en.wikipedia.org/w/index.php?title=Air_conditioning&oldid=635763319"

Categories: 1902 introductions Automation Cooling technology

Heating, ventilating, and air conditioning Home appliances Gas technologies

This page was last modified on 28 November 2014 at 12:06.Text is available under the Creative Commons Attribution-ShareAlike License; additional terms mayapply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is aregistered trademark of the Wikimedia Foundation, Inc., a non-profit organization.

Retrieved on 2012-01-09.

62. ^ "The current status in Air Conditioning – papers & presentations"

(http://www.r744.com/knowledge/papers_result_free.php?

page_no=0&txt_key_free=air%20conditioning&sortby=year%20DESC). R744.com. Retrieved 2010-08-09.

63. ^ http://www.greenpeace.org/usa/en/news-and-blogs/campaign-blog/greenfreeze-f-gas-victory-greener-

refrigerato/blog/38405/
http://en.wikipedia.org/w/index.php?title=Air_conditioning&oldid=635763319http://en.wikipedia.org/wiki/Category:1902_introductionshttp://en.wikipedia.org/wiki/Category:Gas_technologieshttp://www.r744.com/knowledge/papers_result_free.php?page_no=0&txt_key_free=air%20conditioning&sortby=year%20DESChttp://commons.wikimedia.org/wiki/Category:Air_conditionershttp://www.wikimediafoundation.org/http://en.wikipedia.org/wiki/Category:Heating,_ventilating,_and_air_conditioninghttp://wikimediafoundation.org/wiki/Terms_of_Usehttp://www.greenpeace.org/usa/en/news-and-blogs/campaign-blog/greenfreeze-f-gas-victory-greener-refrigerato/blog/38405/http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_Licensehttp://wikimediafoundation.org/wiki/Privacy_policyhttp://en.wikipedia.org/wiki/Category:Cooling_technologyhttp://en.wikipedia.org/wiki/Help:Categoryhttp://en.wikipedia.org/wiki/Category:Home_applianceshttp://en.wikipedia.org/wiki/Category:Automation

air conditioning - wikipedia, the free encyclopedia

Documents