FACTOID # 3: South Carolina has the highest rate of violent crimes and aggravated assaults per capita among US states.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Air conditioning" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Air conditioning

The term air conditioning refers to the cooling and dehumidification of indoor air for thermal comfort. In a broader sense, the term can refer to any form of cooling, heating, ventilation or disinfection that modifies the condition of air.[1] An air conditioner (AC or A/C in North American English, aircon in British and Australian English) is an appliance, system, or mechanism designed to stabilise the air temperature and humidity within an area (used for cooling as well as heating depending on the air properties at a given time) , typically using a refrigeration cycle but sometimes using evaporation, most commonly for comfort cooling in buildings and motor vehicles. Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ... 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... Disinfection is the destruction of pathogenic and other kinds of microorganisms by physical or chemical means. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... The word appliance has several different areas of meaning, all usually referring to a device with a narrow function: One class of objects includes items that are custom-fitted to an individual for the purpose of correction of a physical or dental problem, such as prosthetic, orthotic appliances and dental... For other uses, see System (disambiguation). ... Look up mechanism in Wiktionary, the free dictionary. ... A refrigeration cycle describes the changes that take place to a refrigerant in absorbing heat and subsequently radiating it as it is circulated around a refrigerator. ... Evaporative coolers (also called air, swamp, or desert coolers) devices which use simple evaporation of water in air. ...


The concept of air conditioning is known to have been applied in Ancient Rome, where aqueduct water was circulated through the walls of certain houses to cool them. Similar techniques in medieval Persia involved the use of cisterns and wind towers to cool buildings during the hot season. 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 Willis Haviland Carrier. Ancient Rome was a civilization that grew from a small agricultural community founded on the Italian Peninsula circa the 9th century BC to a massive empire straddling the Mediterranean Sea. ... For other uses, see Aqueduct (disambiguation). ... The Middle Ages formed the middle period in a traditional schematic division of European history into three ages: the classical civilization of Antiquity, the Middle Ages, and modern times. ... 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). ... // Getting water out of a cistern A cistern (Middle English cisterne, from Latin cisterna, from cista, box, from Greek kistê, basket) is a receptacle for holding liquids, usually water. ... It has been suggested that this article or section be merged with windcatcher. ... For other uses, see Chemistry (disambiguation). ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... Year 1902 (MCMII) was a common year starting on Wednesday (link will display calendar) of the Gregorian calendar (or a common year starting on Tuesday [1] of the 13-day-slower Julian calendar). ... This article or section should be merged with Willis Carrier Willis Haviland Carrier (1876 - 1950). ...

Contents

History

While moving heat via machinery to provide air conditioning is a relatively modern invention, the cooling of buildings is not. The ancient Romans were known to circulate aqueduct water through the walls of certain houses to cool them. As this sort of water usage was expensive, generally only the wealthy could afford such a luxury. Ancient Rome was a civilization that grew from a small agricultural community founded on the Italian Peninsula circa the 9th century BC to a massive empire straddling the Mediterranean Sea. ... For other uses, see Aqueduct (disambiguation). ...


The 2nd century Chinese inventor Ding Huan (fl. 180) of the Han Dynasty invented a rotary fan for air conditioning, with seven wheels 3 m (10 ft) in diameter and manually powered.[2] 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.[3] During the subsequent Song Dynasty (960–1279), written sources mentioned the air conditioning rotary fan as even more widely used.[4] Han Dynasty in 87 BC Capital Changan (206 BC–9 AD) Luoyang (25 AD–220 AD) Language(s) Chinese Religion Buddhism, Taoism, Confucianism, Chinese folk religion Government Monarchy History  - Establishment 206 BC  - Battle of Gaixia; Han rule of China begins 202 BC  - Interruption of Han rule 9 - 24  - Abdication... For other uses, see Fan. ... Emperor Tang Xuanzong (唐玄宗) (September 8, 685 - May 3, 762), born Li Longji (李隆基), was the sixth emperor of the Tang dynasty of China, reigning from 712 to 756. ... For the band, see Tang Dynasty (band). ... Northern Song in 1111 AD Capital Bianjing (汴京) (960–1127) Linan (臨安) (1127–1276) Language(s) Chinese Religion Buddhism, Taoism, Confucianism Government Monarchy Emperor  - 960–976 Emperor Taizu  - 1126–1127 Emperor Qinzong  - 1127–1162 Emperor Gaozong  - 1278–1279 Emperor Bing History  - Zhao Kuangyin taking over the throne of the Later Zhou...


Medieval Persia had buildings that used cisterns and wind towers to cool buildings during the hot season: cisterns (large open pools in a central courtyards, not underground tanks) collected rain water; wind towers had windows that could catch wind and internal vanes to direct the airflow down into the building, usually over the cistern and out through a downwind cooling tower.[5] Cistern water evaporated, cooling the air in the building. Persia redirects here. ... // Getting water out of a cistern A cistern (Middle English cisterne, from Latin cisterna, from cista, box, from Greek kistê, basket) is a receptacle for holding liquids, usually water. ... It has been suggested that this article or section be merged with windcatcher. ...


Ventilators were invented in medieval Egypt and were widely used in many houses throughout Cairo during the Middle Ages. These ventillators were later described in detail by Abd al-Latif al-Baghdadi in 1200, who reported that almost every house in Cairo has a ventillator, and that they cost anywhere from 1 to 500 dinars depending on their sizes and shapes. Most ventillators in the city were oriented towards the Qibla, as was the city in general.[6] Return inlet (left)Supply outlet (right). ... During the initial Islamic invasion in 639 AD, Egypt was ruled at first by governors acting in the name of the Ummayad Caliphs in Damascus but, in 747, the Ummayads were overthrown and the power of the Arabs slowly began to weaken. ... For other uses, see Cairo (disambiguation). ... The Middle Ages formed the middle period in a traditional schematic division of European history into three ages: the classical civilization of Antiquity, the Middle Ages, and modern times, beginning with the Renaissance. ... Abdallatif, Abd-el-latif or Abd-Ul-Latif (1162-1231), a celebrated physician and traveller, and one of the most voluminous writers of the East, was born at Baghdad. ... Events University of Paris receives charter from Philip II of France The Kanem-Bornu Empire was established in northern Africa around the year 1200 Mongol victory over Northern China — 30,000,000 killed Births Al-Abhari, Persian philosopher and mathematician (died 1265) Ulrich von Liechtenstein, German nobleman and poet (died... A 25,000 Iraqi dinar note printed after the fall of Saddam Hussein. ... Facing the Qibla at a prayer in Damascus The geometrical calculation of Qibla Qibla () is an Arabic word for the direction that should be faced when a Muslim prays. ...


In 1820, British scientist and inventor Michael Faraday discovered that compressing and liquefying ammonia could chill air when the liquefied ammonia was allowed to evaporate. In 1842, Florida physician John Gorrie used compressor technology to create ice, which he used to cool air for his patients in his hospital in Apalachicola, Florida.[7] He hoped eventually to use his ice-making machine to regulate the temperature of buildings. He even envisioned centralized air conditioning that could cool entire cities.[8] Though his prototype leaked and performed irregularly, Gorrie was granted a patent in 1851 for his ice-making machine. 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 Vivian M. Sherlock, he blamed the "Ice King," Frederic Tudor, for his failure, suspecting that Tudor had launched a smear campaign against his invention. Dr. Gorrie died impoverished in 1855 and the idea of air conditioning faded away for 50 years. 1820 was a leap year starting on Saturday (see link for calendar). ... A scientist, in the broadest sense, refers to any person that engages in a systematic activity to acquire knowledge or an individual that engages in such practices and traditions that are linked to schools of thought or philosophy. ... For other uses, see Inventor (disambiguation). ... Michael Faraday, FRS (September 22, 1791 – August 25, 1867) was an English chemist and physicist (or natural philosopher, in the terminology of that time) who contributed to the fields of electromagnetism and electrochemistry. ... For other uses, see Ammonia (disambiguation). ... 1842 was a common year starting on Saturday (see link for calendar). ... This article is about the U.S. State of Florida. ... NSHC statue of John Gorrie John Gorrie, (October 3, 1802 – June 29, 1855) physician, scientist, inventor, and humanitarian, is considered the father of refrigeration and air conditioning. ... This article is about water ice. ... For the town in the Republic of Ireland, see Hospital, County Limerick. ... 1851 (MDCCCLI) was a common year starting on Wednesday (see link for calendar) of the Gregorian calendar (or a common year starting on Friday of the 12-day-slower Julian calendar). ... Frederic Tudor (September 4, 1783 - February 6, 1864) was Bostons Ice King, the founder of the Tudor Ice Company, and a merchant who made a fortune shipping ice to the Caribbean, Europe, and even as far away as India from sources of fresh water in New England. ... Political campaign Part of the Politics series Politics Portal This box:      This page is about a political tactic. ... Year 1855 (MDCCCLV) was a common year starting on Monday (link will display the full calendar) of the Gregorian Calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ...


Early commercial applications of air conditioning were manufactured to cool air for industrial processing rather than personal comfort. In 1902 the first modern electrical air conditioning was invented by Willis Haviland Carrier. Designed to improve manufacturing process control in a printing plant, his invention controlled not only temperature but also humidity. The low heat and humidity were to help 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 to be used to improve comfort in homes and automobiles. Residential sales expanded dramatically in the 1950s. Year 1902 (MCMII) was a common year starting on Wednesday (link will display calendar) of the Gregorian calendar (or a common year starting on Tuesday [1] of the 13-day-slower Julian calendar). ... For the musical form, see Invention (music). ... This article or section should be merged with Willis Carrier Willis Haviland Carrier (1876 - 1950). ... For other uses, see Temperature (disambiguation). ... The term humidity is usually taken in daily language to refer to relative humidity. ... The Carrier Corporation is the world’s largest manufacturer and distributor of heating, ventilating and air conditioning (HVAC) systems, and a global leader in the commercial refrigeration and food service equipment industry. ... Car redirects here. ...


In 1906, Stuart W. Cramer of Charlotte, North Carolina, USA, was exploring ways to add moisture to the air in his textile mill. Cramer coined the term "air conditioning," using it in a patent claim he filed that year as an analogue to "water conditioning", then a well-known process for making textiles easier to process. He combined moisture with ventilation to "condition" and change the air in the factories, controlling the humidity so necessary in textile plants. Willis Carrier adopted the term and incorporated it into the name of his company. This evaporation of water in air, to provide a cooling effect, is now known as evaporative cooling. 1906 (MCMVI) was a common year starting on Monday (see link for calendar). ... Charlotte redirects here. ... Motto: (traditional) In God We Trust (official, 1956–present) Anthem: The Star-Spangled Banner Capital Washington, D.C. Largest city New York City Official language(s) None at the federal level; English de facto Government Federal Republic  - President George W. Bush (R)  - Vice President Dick Cheney (R) Independence - Declared - Recognized... Evaporative cooling is a system in which latent heat of evaporation is used to carry heat away from an object to cool it. ...


The first air conditioners and refrigerators employed toxic or flammable gases like ammonia, methyl chloride, and propane which could result in fatal accidents when they leaked. Thomas Midgley, Jr. created the first chlorofluorocarbon gas, Freon, in 1928. The refrigerant was much safer for humans but was later found to be harmful to the atmosphere's ozone layer. Freon is a trademark name of DuPont for any Chlorofluorocarbon (CFC), Hydrogenated CFC (HCFC), or Hydrofluorocarbon (HFC) refrigerant, the name of each including a number indicating molecular composition (R-11, R-12, R-22, R-134). The blend most used in direct-expansion home and building comfort cooling is an HCFC known as R-22. It is to be phased out for use in new equipment by 2010 and completely discontinued by 2020. R-12 was the most common blend used in automobiles in the US until 1994 when most changed to R-134. R-11 and R-12 are no longer manufactured in the US, the only source for purchase being the cleaned and purified gas recovered from other air conditioner systems. Several non-ozone depleting refrigerants have been developed as alternatives, including R-410A, known by the brand name Puron. Fridge redirects here. ... For other uses, see Ammonia (disambiguation). ... Chloromethane or Methyl chloride is a chemical compound once widely used as a refrigerant. ... Propane is a three-carbon alkane, normally a gas, but compressible to a liquid that is transportable. ... Thomas Midgley, Jr. ... Freon is a trade name for a group of chlorofluorocarbons used primarily as a refrigerant. ... Year 1928 (MCMXXVIII) was a leap year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... The ozone layer is a layer in Earths atmosphere which contains relatively high concentrations of ozone (O3). ... “(TM)” redirects here. ... This article is about E.I. du Pont de Nemours and Company. ... For other uses, see CFC (disambiguation). ... Hydrochlorofluorocarbons (HCFCs) is one of a class of fluorocarbon compounds that are used primarily as chlorofluorocarbon (CFC) substitutes. ... CFC molecules CFCs (chlorofluorocarbons) are a family of artificial chemical compounds containing chlorine, fluorine and carbon. ... 2010 (MMX) will be a common year starting on Friday of the Gregorian calendar. ... 2020 (MMXX) will be a leap year starting on Wednesday of the Gregorian calendar. ... Year 1994 (MCMXCIV) The year 1994 was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by the United Nations. ... R-410A is an azeotropic mixture of difluoromethane and pentafluoroethane which is used as a refrigerant in air conditioning applications. ...


Innovation in air conditioning technologies continue, with much recent emphasis placed on energy efficiency and improving indoor air quality. As an alternative to conventional refrigerants, natural alternatives like CO2 (R-744) have been proposed.[9] Indoor Air Quality (IAQ) deals with the content of interior air that could affect health and comfort of building occupants. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...


Air conditioning applications

Air conditioning engineers broadly divide air conditioning applications into comfort and process.


Comfort applications aim to provide a building indoor environment that remains relatively constant in a range preferred by humans despite changes in external weather conditions or in internal heat loads. Building indoor environment covers the environmental aspects in the design, analysis, and operation of energy-efficient, healthy, and comfortable buildings. ... Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ...


The highest performance for tasks performed by people seated in an office is expected to occur at 72 °F (22 °C) Performance is expected to degrade about 1% for every 2 °F change in room temperature.[10] The highest performance for tasks performed while standing is expected to occur at slightly lower temperatures. The highest performance for tasks performed by larger people is expected to occur at slightly lower temperatures. The highest performance for tasks performed by smaller people is expected to occur at slightly higher temperatures. Although generally accepted, some dispute that thermal comfort enhances worker productivity, as is described in the Hawthorne effect. The Hawthorne effect refers to a phenomenon of observing workers behavior or their performance and changing it temporarily. ...


Comfort air conditioning makes deep plan buildings feasible. Without air conditioning, buildings must be built narrower or with light wells so that inner spaces receive sufficient outdoor air via natural ventilation. Air conditioning also allows buildings to be taller since wind speed increases significantly with altitude making natural ventilation impractical for very tall buildings. Comfort applications for various building types are quite different and may be categorized as A deep plan building is a building in which the horizontal distance from the external wall is many times greater than the floor to floor height. ... Natural ventilation is the process of supplying and removing air through an indoor space by natural means. ... A wind gradient describes the change in velocity and/or direction of the wind in a certain direction. ...

  • Low-Rise Residential buildings, including single family houses, duplexes, and small apartment buildings
  • High-Rise Residential buildings, such as tall dormitories and apartment blocks
  • Commercial buildings, which are built for commerce, including offices, malls, shopping centers, restaurants, etc.
  • Institutional buildings, which includes hospitals, governmental, academic, and so on.
  • Industrial spaces where thermal comfort of workers is desired.

In addition to buildings, air conditioning can be used for comfort in a wide variety of transportation including land vehicles, trains, ships, aircraft, and spacecraft. The Trikke is a Human Powered Vehicle (HPV) Automobiles are among the most commonly used engine powered vehicles. ... For other uses, see Train (disambiguation). ... For other uses, see Ship (disambiguation). ... Flying machine redirects here. ... The Space Shuttle Discovery as seen from the International Space Station. ...


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. Although often in the comfort range, it is the needs of the process that determine conditions, not human preference. Process applications include these:

  • 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).
  • Facilities for breeding laboratory animals. Since many animals normally only reproduce in spring, holding them in rooms at which conditions mirror spring all year can cause them to reproduce year round.
  • Aircraft air conditioning. Although nominally aimed at providing comfort for passengers and cooling of equipment, aircraft air conditioning presents a special process because of the low air pressure outside the aircraft.

In both comfort and process applications the objective may be to not only control temperature, but also humidity, air quality, air motion, and air movement from space to space. An operating theatre (gynecological hospital of Medical University of Silesia in Bytom) An operating theatre, operating room, or a surgery suite is a room within a hospital within which surgical operations are carried out. ... An infection is the detrimental colonization of a host organism by a foreign species. ... Cardiac surgery is surgery on the heart, typically to treat complications of ischemic heart disease (e. ... A human infant The word Infant derives from the Latin in-fans, meaning unable to speak. ... For the Cleanroom software engineering methodology, see Cleanroom Software Engineering. ... An integrated circuit (IC) is a thin chip consisting of at least two interconnected semiconductor devices, mainly transistors, as well as passive components like resistors. ... Pharmacology (in Greek: pharmacon is drug, and logos is science) is the study of how chemical substances interfere with living systems. ... The data suggest that use of laboratory animals allowed to add 28 years of life to an average human. ... Spring is one of the four temperate seasons. ... For other uses, see Data entry clerk. ... Textile manufacturing is one of the oldest of mans technologies. ... This article is about applications of nuclear fission reactors as power sources. ... For other uses, see Chemistry (disambiguation). ... For the song by Girls Aloud see Biology (song) Biology studies the variety of life (clockwise from top-left) E. coli, tree fern, gazelle, Goliath beetle Biology (from Greek: Βιολογία - βίος, bio, life; and λόγος, logos, speech lit. ... This article does not cite any references or sources. ... This article is about mineral extractions. ... Industrial ecology is the shifting of industrial process from open loop systems, in which resource and capital investments move through the system to become waste, to a closed loop system where wastes become inputs for new processes. ... Cooking is the act of preparing food. ... Food processing is the set of methods and techniques used to transform raw ingredients into food for consumption by humans or animals. ... The term humidity is usually taken in daily language to refer to relative humidity. ...


Humidity control

Refrigeration air conditioning equipment usually reduces the humidity of the air processed by the system. The relatively cold (below the dewpoint) evaporator coil condenses water vapor from the processed air, (much like an ice-cold drink will condense water on the outside of a glass), sending the water to a drain and removing water vapor from the cooled space and lowering the relative humidity. 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% to 60% relative humidity in the occupied space. In food retailing establishments large open chiller cabinets act as highly effective air dehumidifying units. The term humidity is usually taken in daily language to refer to relative humidity. ... 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. ... Vaporization redirects here. ...


A specific type of air conditioner that is used only for dehumidifying is called a dehumidifier. A dehumidifier is different from a regular air conditioner in that both the evaporator and condensor coils are placed in the same air path, and the entire unit is placed in the environment that is intended to be conditioned (in this case dehumidified), rather than requiring the condensor coil to be outdoors. Having the condensor coil in the same air path as the evaporator coil produces warm, dehumidified air. The evaporator (cold) coil is placed first in the air path, dehumidifying the air exactly as a regular air conditioner does. The air next passes over the condensor coil re-warming the now dehumidified air. Note that the terms "condensor coil" and "evaporator coil" do not refer to the behavior of water in the air as it passes over each coil; instead they refer to the phases of the refrigeration cycle. Having the condensor coil in the main air path rather than in a separate, outdoor air path (as in a regular air conditioner) results in two consequenses-- the output air is warm rather than cold, and the unit is able to be placed anywhere in the environment to be conditioned, without a need to have the condensor outdoors. A dehumidifier is a household appliance that reduces the level of humidity in the air. ... A refrigeration cycle describes the changes that take place to a refrigerant in absorbing heat and subsequently radiating it as it is circulated around a refrigerator. ...


Ironically, unlike a regular air conditioner, a dehumidifier will actually heat a room just as an electric heater that draws the same amount of electricity (watts) as the dehumidifier. A regular air conditioner transfers energy out of the room by means of the condensor coil, which is outside the room (outdoors). This is a thermodynamic system where the room serves as the system and energy is transferred out of the system. Conversely with a dehumidifier, no energy is transferred out of the thermodynamic system (room) because the air conditioning unit (dehumidifier) is entirely inside the room. Therefore all of the electricity that is consumed by the dehumidifier is energy that is input into the thermodynamic system (the room), and remains in the room (as heat). A furnace is a device for heating air or any other fluid. ... Watts may refer to: Watt, the SI derived unit of power Watts and Co. ... Thermodynamics (Greek: thermos = heat and dynamic = change) is the physics of energy, heat, work, entropy and the spontaneity of processes. ...


Dehumidifiers are commonly used in cold, damp climates to prevent mold growth indoors, especially in basements. They are also sometimes used in hot, humid climates for comfort because they reduce the humidity which causes discomfort (just as a regular air conditioner, but without cooling the room). This article is about the fungi known as molds. ...


Health implications

A poorly maintained air-conditioning system can occasionally promote the growth and spread of microorganisms, such as Legionella pneumophila, the infectious agent responsible for Legionnaires' disease, or thermophilic actinomycetes.[11] Conversely, air conditioning, including filtration, humidification, cooling, disinfection, etc., can be used to provide a clean, safe, hypoallergenic atmosphere in hospital operating rooms and other environments where an appropriate atmosphere is critical to patient safety and well-being. Air conditioning can have a positive effect on sufferers of allergies and asthma.[12] Binomial name Legionella pneumophila Brenner DJ, Steigerwalt AG, McDade JE 1979 Legionella pneumophila is a thin, pleomorphic, flagellated Gram-negative bacterium of the genus Legionella. ... Legionellosis is an infectious disease caused by bacteria belonging to the genus Legionella. ... Actinomycetales, commonly referred to as Actinomycetes, is an order of bacteria in the class Actinobacteria. ... Look up hypoallergenic in Wiktionary, the free dictionary. ... Allergy is an abnormal reaction to a substance foreign to the body that is acquired, predictable and rapid. ...


In serious heat waves, air conditioning can save the lives of the elderly. Some local authorities even set up public cooling centers for the benefit of those without air conditioning at home. For other uses, see Heat wave (disambiguation). ... A cooling center is a temporary air-conditioned public space set up by local authorities to deal with the health effects of a heat wave. ...


Poorly operating air conditioning systems can generate sound levels that contribute to hearing loss, if exposures are endured over a long term. These levels are similar to the exposure of living near a busy highway or airport for a considerable length of time. Properly functioning air conditioners are much quieter.


Energy use

It should be noted that in a thermodynamically closed system, any energy input into the system that is being maintained at a set temperature (which is a standard mode of operation for modern air conditioners) requires that the energy removal rate from the air conditioner increase . This increase has the effect that for each unit of energy input into the system (say to power a light bulb in the closed system) requires the air conditioner to remove that energy. In order to do that the air conditioner must increase its consumption by the inverse of its efficiency times the input unit of energy. As an example presume that inside the closed system a 100 watt light bulb is activated, and the air conditioner has an efficiency of 200%. The air conditioner's energy consumption will increase by 50 watts to compensate for this, thus making the 100 W light bulb utilise a total of 150 W of energy. In thermodynamics, a closed system, as contrasted with an isolated system, can exchange heat and work, but not matter, with its surroundings. ...


Note that it is typical for air conditioners to operate at "efficiencies" of significantly greater than 100%, see Coefficient of performance. The coefficient of performance, or COP (sometimes CP), of a heat pump is the ratio of the output heat to the supplied work or where Q is the useful heat supplied by the condenser and W is the work consumed by the compressor. ...


Portable air conditioners

A portable air conditioner or portable A/C is an air conditioner on wheels that can be easily transported inside a home or office. They are currently available with capacities of about 6,000 to 60,000 BTU/h (1,800 to 18,000 watts output) and with and without electric resistance heaters. Portable air conditioners come in three forms, split, hose and evaporative: Split refers to: verb split, cf. ... Plastic hoses. ... Evaporative coolers (also called air, swamp, or desert coolers) devices which use simple evaporation of water in air. ...


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


Hose systems Air-to-Air and Monoblock are vented to the outside via air ducts. A function of all cooling that use a compressor, is to create water as it cools the air. The "monoblock" version collects the water in a bucket or tray and stops when full. The Air-to-Air version, re-evaporates the water and discharges it through the ducted hose and can hence run continuously. A round galvanized steel duct connecting to a typical diffuser Fire-resistance rated mechanical shaft with HVAC sheet metal ducting and copper piping, as well as HOW (Head-Of-Wall) joint between top of concrete block wall and underside of concrete slab, firestopped with ceramic fibre-based firestop caulking on...


A single duct unit draws air out of the room to cool its condenser. This air is then replaced by hot air from outside or other rooms, thus reducing efficiency. However, modern units run on approximately 1 to 3 ratio i.e., to produce 3 kW of cooling this will use 1 kW of electricity. A dual duct unit will draw air from outside to cool its condenser instead of from inside the room, and thus is more efficient than most single duct units.


Air cooled portable air conditioners are compressor-based refrigerant system that uses air to exchange heat, similar to a car or typical household air conditioner. With this type of system the air is dehumidified as it is cooled.


Evaporative air conditioners do not have a compressor or condenser. Instead, liquid water is poured in and released as vapour. Because they do not have a condenser which needs cooling, they do not need hoses or pipes, allowing them to be truly portable.


As a rule of thumb, 400 square feet (37 m²) can be cooled per 12,000 BTU/h (3.5 kW or one ton of air conditioning) by a refrigerative air conditioner. However, other factors will affect the total heat load. Evaporative air conditioners use much less energy.


Heat pumps

See the article on heat pumps. A heat pump is a machine, which moves heat from a low temperature reservoir to a higher temperature reservoir under supply of work. ...


Heat pump is a term for a type of air conditioner in which the refrigeration cycle is able to be reversed, producing heat instead of cold in the indoor environment. Using an air conditioner in this way to produce heat is significantly more efficient than electric resistance heating. Some home-owners elect to have a heat pump system installed, which is actually simply a central air conditioner with heat pump functionality (the refrigeration cycle is reversed in the winter). When the heat pump is enabled, the indoor evaporator coil switches roles and becomes the condensor coil, producing heat. The outdoor condensor unit also switches roles to serve as the evaporator, and produces cold air (colder than the ambient outdoor air). A refrigeration cycle describes the changes that take place to a refrigerant in absorbing heat and subsequently radiating it as it is circulated around a refrigerator. ...


Heat pumps are more popular in milder winter climates where the temperature is frequently in the range of 40-55° F (4-13° C), because heat pumps become inefficient in more extreme cold. This is due to the problem of the outdoor unit's coil forming ice which blocks air flow over the coil. To compensate for this, the heat pump system must temporarily switch back into the regular air conditioning mode to switch the outdoor evaporator coil back to being the condensor coil so that it can heat up and de-ice. A heat pump system therefore will have a form of electric resistance heating in the indoor air path that is activated only in this mode in order to compensate for the temporary air conditioning, which would otherwise generate undesirable cold air in the winter. The icing problem becomes much more prevalent 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 efficiciently during the milder temperatures, and the system is switched to the conventional heat source when the outdoor temperature is lower. For other uses, see Natural gas (disambiguation). ... Heating oil, or burning oil, also known in the United States as No. ... A furnace is a device for heating air or any other fluid. ...


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


Professional bodies

American Society of Heating, Refrigerating, and Air-Conditioning Engineers

ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) is an organization devoted to the advancement of indoor-environment-control technology in the heating, ventilation, and air conditioning (HVAC) industry. ASHRAE was founded in 1894 to serve as a source of technical standards and guidelines. Since that time, it has grown into an international society that offers educational information, courses, seminars, career guidance, and publications. The organization also promotes a code of ethics for HVAC professionals and provides for liaison with the general public.


Australian Institute of Refrigeration Air Conditioning and Heating

The Australian Institute of Refrigeration Air Conditioning and Heating (AIRAH) was founded in 1920 and currently has around 10,000 members.


See also

Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... This article is about refrigerants. ... For the physical concepts, see conservation of energy and energy efficiency. ... Evaporative coolers (also called air, swamp, or desert coolers) devices which use simple evaporation of water in air. ... Evaporative cooling is a system in which latent heat of evaporation is used to carry heat away from an object to cool it. ... A heat pump is a machine or device that moves heat from one location (the source) to another location (the sink), using work. ... 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... 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. ... Characterizing how air is introduced to, flows through, and is removed from spaces is called room air distribution. ... Steam jet cooling is a method of cooling water by using a high-pressure jet of steam. ... Designers at work in 1961. ... Car redirects here. ... The body of a motor vehicle which is built around a chassis, rather than being of monocoque construction. ... Look up Chassis in Wiktionary, the free dictionary. ... Body-on-frame is an automobile construction technology. ... The bumper of a BMW M5, highlighted in red A bumper is a part of an automobile designed to allow one vehicle to impact with another and to withstand that collision without severe damage to the vehicles frame. ... A Citroën 2CV with the roof up. ... Look up Chassis in Wiktionary, the free dictionary. ... 1956 Nash four-door sedan with factory color matched Continental tire. ... Mercedes-Benz Fintail, an early example of a car with crumple zones The crumple zone on the front of these cars absorbed the impact of a head-on collision Activated rear crumple zone The crumple zone of a vehicle such as a train or an automobile is a structural feature... 1958 promotional image of the Cadillac Eldorado Brougham also illustrates its bumper/grille design, also known as Dagmar bumpers Television personality Dagmar in one of her famous low cut gowns Dagmar bumpers, also known simply as Dagmars (D-HAG-mar) is a slang term for the artillery shell shaped styling... The decklid (or deck lid) is the cover over the trunk/boot of motor vehicles that allows access to the main storage or luggage compartment. ... Choppers often have stylized fenders Fender is the US English term for the part of an automobile, motorcycle or other vehicle body that frames a wheel well. ... 1962 Cadillac Series 62 with rear wheels covered by detachable Fender Skirts 1986 Citroën CX Fender skirts are pieces of bodywork that cover the upper portions of the rear tires of an automobile. ... BMWs distinctive kidney-shaped grille on an E34 M5 Audis single frame grille, here on a second generation TT Grille is also the name of a German self-propelled artillery vehicle. ... This article is about a part of a vehicle. ... A hood scoop is an air vent on a car hood which usually sends air over an intercooler. ... Monocoque (French for single shell) is a construction technique that uses the external skin of an object to support some or most of the load on the structure. ... An SUV with four pillars A pillarless hardtop vehicle, considered to have two total pillars A stretch limo with five pillars An A pillar is a name applied by car stylists and enthusiasts to the shaft of material that supports the windshield (windscreen) on either of the windshield frame sides. ... Pontoon fenders are a type of fender for an automobile. ... On an automobile, a quarter panel is a body panel that covers the section between the door and the hood (for the front quarter panels), or the door and the trunk (for the rear quarter panels). ... A shaker scoop (sometimes, inaccurately, called a shaker hood scoop or a shaker hood) is an automobile term for an air intake scoop for combustion air that is mounted directly on top of the engines air cleaner and protrudes through a hole in the hood. ... This Ford F-150 pickup truck has two spoilers one on the roof and another on the tailgate. ... It has been suggested that this article or section be merged with Sub frame. ... 1903 Ford Model A rear-door Tonneau Tonneau is an archaic term for an open rear passenger compartment on an automobile and, by extension, a body style incorporating such a compartment. ... This 1931 Ford Model A features a separate trunk on its rear trunk rack. ... This article is about a part of a vehicle. ... A car door is generally an opening to enter to the car (or their compartments or partition), often equipped with a hinged or sliding panel which can be moved to leave the opening accessible, or to close it more or less securely. ... 1996 McLaren F1 with butterfly doors Butterfly doors, also called vertical doors or dihedral doors, are a type of door often seen on high-performance automobiles. ... A De Lorean DMC-12 with its doors open A Bricklin SV-1 with its doors open The term gull-wing door is used to describe automobile doors which are hinged at the roof. ... Scissor doors, also called Jackknife doors, are automobile doors that rotate up and forward on a hinge near the front of the door. ... Rear suicide door on a 1967 Ford Thunderbird Front suicide door on a Fiat Multipla 600 Lloyd LT 600 van with front suicide door Suicide doors are automobile doors that are hinged on the trailing edge; the edge closer to the rear of the vehicle. ... Power windows or electric windows are automobile windows which can be raised and lowered by depressing a button or switch, as opposed to using a hand-turned crank handle. ... The greenhouse (or glasshouse) of a car comprises the windscreen, rear and side windows, the more or less vertical pillars separating them (designated A-pillar, B-pillar and so on, starting from the cars front), and the cars roof. ... Open sunroof in a Peugeot 206. ... Sun visor inside a 1993 Jeep Grand Cherokee. ... Panoramic (wrap-around) windshield on a 1959 Edsel Corsair. ... windscreen wiper on a parked car. ... Windshield washer fluid being poured into a vehicle Windshield washer fluid is a fluid for motor vehicles that is used in cleaning the windshield while the vehicle is being driven. ... Curb feeler mounted behind the front wheel of a 1950s Rambler American. ... Bumper stickers are often used on commercial vehicles so that employers can receive feedback about the driving habits of their employees A bumper sticker is an adhesive label or sticker with a message, intended to be attached to the bumper of an automobile and to be read by the occupants... A hood ornament is the name given to a specially crafted model of something which symbolises a car company like a badge. ... Japan Black is the name of a lacquer used extensively in the production of automobiles in the early 20th century in the United States. ... A monsoonshield is mounted above the doors of some automobiles, to protect the inside of the car from rain or other precipitation in case of slightly opened windows. ... A 2002 Ford Explorer Sport Trac with black nerf bars A nerf bar is a tubular device fitted to the side of a Pickup truck or a Sport utility vehicle to act as a step to ease entry and exit from the vehicle. ... Firestone tire This article is about pneumatic tires. ... The various pieces of a tow hitch (also known as a tow bar) are as follows (as seen on cars and non-industrial trucks). ... A Truck Accessory is an aftermarket part that is used to enhance the style or function of the original OEM pickup truck. ... Exterior equipment of a vehicle consist of the automotive lighting, distance sensor, vanity plates, vehicle registration plate, windscreen wiper and windshield washer fluid. ... Blinker redirects here. ... Daytime Running Lamps (DRL, also Daylight Running Lamps, Daytime Running Lights) are lighting devices on the front of roadgoing motor vehicles, automatically switched on when the vehicle is moving forward, and intended to increase the conspicuity of the vehicle during daylight conditions. ... This article does not cite any references or sources. ... 1937 Cord 812 with hidden headlights Promotional art for the 1942 DeSoto, the first mass produced American car with hidden headlights 1967 Ford Thunderbird with hidden headlights Pop-up headlights on a 1973 SAAB Sonett III. Hidden headlamps are an automotive styling feature that conceals an automobiles headlights when... 15 kW Xenon short-arc lamp used in IMAX projectors High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium (Son), low-pressure sodium (Sox) and less common, xenon short-arc lamps. ... Retroreflectors are clearly visible in a pair of bicycle shoes. ... A burnt-out sealed beam, broken open to show internals. ... Trafficators are the internally lit semaphores springing out from the door pillars on some older (pre 1950s) motor vehicles to signal left and right turns. ... A vehicle registration plate is a metal or plastic plate attached to a motor vehicle or trailer for official identification purposes. ... A vanity plate (US), prestige plate, private number plate, personalised registration (UK) or personalised plate (Australia and New Zealand) is a special type of vehicle registration plate on an automobile or other vehicle. ... Parktronic, also called Acoustic Parking System (APS), is a parking-assistence system installed on some Audi vehicles. ... Motor vehicle theft is a crime of theft. ... Automobile interior equipment generally includes passive safety, dashboard, shifter for selecting gear ratios and ancillary. ... Vehicle instrument is an instrument that measures some parameters in the vehicle, often found on its control panel or dashboard. ... A backup camera is a special type of video camera that is produced specifically for the purpose of being attached to the rear of a vehicle to aid in backing up. ... Boost gauge on a Ford Focus RS (left) A boost gauge is a pressure gauge that indicates manifold air pressure or turbocharger or supercharger boost pressure in an internal combustion engine. ... A buzzer or beeper is a signaling device, usually electronic, typically used in automobiles, household appliances such as a microwave oven, or game shows. ... Carputer is a term sometimes used to refer to a computer installed in a car. ... A fuel gauge (or gas gauge) is an instrument used to indicate the level of fuel contained in a tank. ... GPS redirects here. ... A taxi in Kyoto, equipped with GPS navigation system An automotive navigation system is a satellite navigation system designed for use in automobiles. ... This article does not cite any references or sources. ... An idiot light is a method of displaying information about a system (e. ... A Malfunction Indicator Lamp, this one labeled Service Engine Soon. A Malfunction Indicator Lamp (MIL) is an indicator of the internal status of a car engine. ... Night-vision is seeing in the dark. ... A modern non-digital odometer A Smiths speedometer from the 1920s showing odometer and trip meter An odometer is a device used for indicating distance traveled by an automobile or other vehicle. ... An early radar detector A radar detector, sometimes called a fuzz buster, is an electronic device used by motorists to determine if their speed is being monitored by a radar unit. ... Speedometer gauge on a car, showing the speed of the vehicle in miles and kilometres per hour on the out– and inside respectively. ... Tachometer showing engine RPM (revolutions per minute), and a redline from 6000 and 7000 RPM. A tachometer is an instrument that measures the speed of rotation of a shaft or disk, as in a motor or other machine. ... A trip computer is an onboard computer device fitted to cars which can generally record distance travelled, average speed, average fuel consumption, and display real time fuel consumption information. ... Invented by Frank Bowden, a bowden cable is a type of flexible cable used to transmit mechanical force or energy by the movement of an inner cable (most commonly of steel or stainless steel) relative to a hollow outer cable housing. ... Cruise control (sometimes known as speed control or Autocruise) is a system to automatically control the speed of an automobile. ... Electronic throttle control (ETC) is an automobile technology which severs the direct link between the accelerator pedal and the throttle. ... A gear stick (also gearstick, gear lever and gear shifter) is the lever used to change gear in a vehicle, such as an automobile, with manual transmission or automatic transmission. ... In cars, the hand brake (also known as the emergency brake, e-brake, park brake, or parking brake) is a supplementary system that can be used if the vehicles primary brake system (usually hydraulic brakes) has a failure. ... Manettino dials are part of modern super cars (like the new Ferrari 599 GTB and Ferrari Enzo). ... A modern road cars steering wheel Steering wheels from different periods A steering wheel is a type of steering control used in most modern land vehicles, including all mass-production automobiles. ... In an engine, the throttle is the mechanism by which the engines power is increased or decreased. ... Motor vehicle theft is a crime of theft. ... Power door locks (aka electric door locks or central locking) allow the driver or front passenger to simultaneously lock or unlock all the doors of an automobile or truck, by pressing a button or flipping a switch. ... A car alarm is an electronic device installed in a vehicle in an attempt to discourage theft. ... An immobiliser or immobilizer is an electronic device fitted to an automobile which prevents the engine from running unless the correct key (or other token) is present. ... For the English band, see Klaxons. ... Automatic vehicle location or AVL is a means for determining the geographic location of a vehicle and transmitting this information to a point where it can be used. ... VIN etching is a countermeasure to motor vehicle theft. ... Passive safety redirects here. ... A car seat usually refers to a small seat secured to the seat of an automobile equipped with safety harnesses to hold children in the event of a crash. ... For the Mozilla crash reporting software previously called Airbag, see Breakpad. ... The armrest in the backseat of a Lincoln Town Car, featuring cupholders. ... Automatic seat belt in a Chevrolet Corsica Automatic seat belts are seat belts that automatically close over riders in a car. ... The traditional seat installed in American automobiles was the bench seat. ... A bucket seat is an upholstered seat in a car, truck, or motorboat that seats one person. ... This article or section does not cite its references or sources. ... This 1931 Ford Model A sport roadster features a rumble seat A rumble seat, dicky seat, dickie seat or dickey seat is an upholstered exterior seat which hinges or otherwise opens out from the rear deck of a pre-World War II automobile, and seats one or more passengers. ... This article is about the safety device. ... Automobile accessory power can be produced by several different means. ... It has been suggested that In car entertainment be merged into this article or section. ... ... The center console (British English: centre console) in an automobile refers to the control-bearing surfaces in the center of the front of the vehicles interior. ... A dashboard from a 1940s car The dashboard of a modern car, a Bentley Continental GT A Hayabusas dash A modern Formula 1 car has all its gauges mounted on the steering wheel A dashboard or dash board in an automobile is a panel located under the windscreen and... A flat tire means the motorist must use the spare tire In a motor vehicle, a flat tire occurs when a tire becomes deflated and the metal of the wheel comes in contact with the ground below (or ground level). ... The glovebox of a Cadillac Eldorado Brougham For the sealed container for handling hazardous materials, see glovebox. ... Typical Motorola plug found on consumer auto accessory antenna coaxial cables A common coaxial cable connector used primarily in the automotive industry for connecting the coaxial feedline from the antenna to the radio receiver. ... Electric window controls between the front seats, including lockout switch (2005 Saab 9-5). ... The rear-view mirror of a Mazda 626. ...

References

  1. ^ ASHRAE Terminology of HVAC&R, ASHRAE, Inc., Atlanta, 1991,
  2. ^ Needham, Joseph (1986). Science and Civilization: Volume 4, Physics and Physical Technology, Part 2, Mechanical Engineering. Taipei: Caves Books Ltd. Pages 99, 151, 233.
  3. ^ Needham, Joseph (1986). Science and Civilization: Volume 4, Physics and Physical Technology, Part 2, Mechanical Engineering. Taipei: Caves Books Ltd. Pages 134 & 151.
  4. ^ Needham, Joseph (1986). Science and Civilization: Volume 4, Physics and Physical Technology, Part 2, Mechanical Engineering. Taipei: Caves Books Ltd. Page 151.
  5. ^ Ancient air conditioning, The World, January 11, 2007 [1]
  6. ^ David A. King (1984). "Architecture and Astronomy: The Ventilators of Medieval Cairo and Their Secrets", Journal of the American Oriental Society 104 (1), p. 97-133.
  7. ^ History of Air Conditioning Source: Jones Jr., Malcolm. "Air Conditioning". Newsweek. Winter 1997 v130 n24-A p42(2). Retrieved 1 January 2007.
  8. ^ The History of Air Conditioning Lou Kren, Properties Magazine Inc. Retrieved 1 January 2007.
  9. ^ The current status in Air Conditioning - papers & presentations
  10. ^ EVALUATION OF COST EFFECTIVENESS OF INDOOR CLIMATE Retrieved 1 January 2007.
  11. ^ Sick building syndrome
  12. ^ Home Control of Asthma & Allergies
is the 1st day of the year in the Gregorian calendar. ... is the 1st day of the year in the Gregorian calendar. ... is the 1st day of the year in the Gregorian calendar. ...

  Results from FactBites:
 
Air Conditioning & Refrigeration (469 words)
Whether at work or relaxing at home, air conditioning can make a big difference to your environment: getting the best out of the working day and enjoying to the full your home environment.
And many more homeowners now consider air conditioning as important as their home heating system.
Split air conditioning systems are particularly beneficial as the condenser (housing the motor, etc) is installed outside the building, ensuring quiet operation inside.
Air Conditioning (1218 words)
Air conditioning is the process by which air is cooled and dehumidified.
The air surrounding the glass becomes cooler when it encounters the cold glass, and the water vapor the air is carrying condenses into water.
The best thing about air conditioning is that all you have to do is press a button to make it work.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m