It has been suggested that Portable air conditioner be merged into this article or section. (Discuss)

The external section of a typical single-room air conditioning unit. For ease of installation, these are frequently placed in a window. This one was installed through a hole cut in the wall.

The internal section of the same unit. The front panel swings down to reveal the controls.

Note: in the broadest sense, "air conditioning" can refer to any form of "heating, ventilation, and air-conditioning." This article is specifically about the use of refrigeration for this purpose.

The first album of the pop group Curved Air was called Airconditioning

An air conditioner is an appliance, system, or mechanism designed to extract heat from an area using a refrigeration cycle. In construction, a complete system of heating, ventilation, and air conditioning is referred to as HVAC. Image File history File links Please see the file description page for further information. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Image File history File links Download high resolution version (1419x1347, 157 KB) Summary Created by myself on November 1, 2005. ... Image File history File links Download high resolution version (1419x1347, 157 KB) Summary Created by myself on November 1, 2005. ... Image File history File linksMetadata Download high resolution version (1773x1341, 198 KB) Summary Created by myself on November 17, 2005. ... Image File history File linksMetadata Download high resolution version (1773x1341, 198 KB) Summary Created by myself on November 17, 2005. ... HVAC (pronounced either H-V-A-C or, occasionally, H-VAK) is an initialism/acronym that stands for heating, ventilating and air-conditioning. This is sometimes referred to as climate control. ... It has been suggested that Refrigerator be merged into this article or section. ... Curved Air is a progressive rock group formed in 1970. ... 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 problem, such as prosthetic and orthotic appliances. ... Look up system in Wiktionary, the free dictionary. ... Mechanism is the following: In general, a mechanism is part of a chain of causes leading to some object or process. ... HVAC (pronounced either H-V-A-C or, occasionally, H-VAK) is an initialism/acronym that stands for heating, ventilating and air-conditioning. This is sometimes referred to as climate control. ...

History

The 19th century British scientist and inventor Michael Faraday discovered that compressing and liquefying ammonia could chill air when the liquefied ammonia was allowed to evaporate. The physicist Albert Einstein is probably historys most widely recognized scientist. ... An inventor is a person who creates new inventions, typically technical devices such as mechanical, electrical or software devices or methods. ... Michael Faraday from a photograph by John Watkins, British Library [1] Michael Faraday, FRS (September 22, 1791 – August 25, 1867) was a British chemist and physicist (he considered himself a natural philosopher) who contributed significantly to the fields of electromagnetism and electrochemistry. ...

In 1842, Florida physician Dr. John Gorrie used compressor technology to create ice, which he used to cool air for his patients.[1] 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.[2] 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 has launched a smear campaign against his invention. After Gorrie's death in 1855 the idea of air conditioning faded away for some years. 1842 was a common year starting on Saturday (see link for calendar). ... Official language(s) English Capital Tallahassee Largest city Jacksonville Area  Ranked 22nd  - Total 65,794 sq mi (170,451 km²)  - Width 162 miles (260 km)  - Length 497 miles (800 km)  - % water 17. ... 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. ... The acronym ICE can refer to: InterCity Express, a German high-speed train InterCity Express (CityTrain), an interurban train used by QR CityTrain in South East Queensland, Australia Internal combustion engine, a fuel engine In-circuit emulator, a computer hardware device In case of emergency, emergency number in mobile phones... 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. ... 1855 was a common year starting on Monday (see link for calendar). ...

Early commercial applications of air conditioning were to 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 in to meet the rising demand. Over time air conditioning came to be used to improve comfort in homes and automobiles. Residential sales expanded dramatically in the 1950s. 1902 (MCMII) was a common year starting on Wednesday (see link for calendar). ... An invention is an object, process, or technique which displays an element of novelty. ... This article or section should be merged with Willis Carrier Willis Haviland Carrier (1876 - 1950). ... Temperature is also the name of a song by Sean Paul. ... Humidity is the concentration of water vapor in the air. ... The Carrier Corporation is the air conditioning manufacturing division of United Technologies. ... This article or section does not cite its references or sources. ...

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 work. 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. 1906 (MCMVI) was a common year starting on Monday (see link for calendar). ... Flag Nickname: The Queen City, The Hornets Nest Location Location in Mecklenburg County in the state of North Carolina Coordinates , Government Country State Counties United States North Carolina Mecklenburg County, North Carolina Mayor Pat McCrory, (R) Geographical characteristics Area     City 280. ...

The first air conditioners and refrigerators employed toxic gases like ammonia and methyl chloride, 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 trade name of Dupont for any CFC, HCFC, or 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 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-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 ozone-friendly refrigerants have been developed as alternatives, including R-410A, known by the brand name "Puron". It has been suggested that this article or section be merged into refrigeration. ... Ammonia is a compound of nitrogen and hydrogen with the formula NH3. ... Chloromethane or Methyl chloride is a chemical compound once widely used as a refrigerant. ... Thomas Midgley, Jr. ... Freon is a trade name for a group of chlorofluorocarbons used primarily as a refrigerant. ... 1928 (MCMXXVIII) was a leap year starting on Sunday (link will take you to calendar). ... The ozone layer, or ozonosphere layer (rarely used term), is that part of the Earths atmosphere which contains relatively high concentrations of ozone (O3). ... Possible meanings: Certified Financial Consultant Chelsea Football Club Child and Family Canada Chlorofluorocarbon Combined Federal Campaign haloalkane This page concerning a three-letter acronym or abbreviation is a disambiguation page—a list of articles associated with the same title. ... 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. ... R-410A is an azeotropic mixture of difluoromethane and pentafluoroethane which is used as a refrigerant in air conditioning applications. ...

Air conditioning applications

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

Comfort applications aim to provide an indoor environment that remains relatively constant in a range preferred by humans despite changes in external weather conditions or in internal heat loads. Some have claimed that comfort air conditioning increases worker productivity but this claim is disputed, one counter argument being that apparent increases in productivity can be explained as resulting from workers perceiving that their employer shows an interest in their welfare. (See Hawthorne effect). What is certain is that 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 fresh air. Air conditioning also allows building to be taller since wind speed increases significantly with altitude making natural ventilation impractical for very tall buildings. Comfort applications for various buiding types is quite different and may be categorized as: To meet Wikipedias quality standards, this article or section may require cleanup. ... 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. ... A wind gradient describes the change in velocity and/or direction of the wind in a certain direction. ... Return inlet (left)Supply outlet (right). ...

• Residential Buildings including single family houses and hi-rise buildings.
• Institutional Buildings includes Hi-Rise offices, large complex buildings, hospitals, and so on
• Commercial Buildings which are built for profit and commerce, including malls, shopping centers, apartment housings, etc.

Process applications aim to provide a suitable environment for a process being carried out, regardless of internal heat 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:

• Hospital operating Suites 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).

• Cleanrooms 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.

• 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.

• Data Processing Centers
• Textile Factories
• Physical Testing Facilities
• Plants and Farm Growing Areas
• Nuclear Facilities
• Mines
• Industrial Envirinments
• Food Cooking and Processing Areas

In both comfort and process applications not only is the objective to control temperature (although in some comfort applications this is all that is controlled) but other factors including humidity, air movement and air quality. 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. ... NASAs Glenn Research Center cleanroom. ... 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. ...

Air Conditioning System Basics and Theories

Refrigeration cycle

A diagram of the refrigeration cycle: 1) condensing coil, 2) expansion valve, 3) evaporator coil, 4) compressor.

In the refrigeration cycle, a heat pump transfers heat from a lower temperature heat source into a higher temperature heat sink. Heat would naturally flow in the opposite direction. This is the most common type of air conditioning. A refrigerator works in much the same way, as it pumps the heat out of the interior into the room in which it stands. Image File history File links Heatpump. ... Image File history File links Heatpump. ... 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. ... A diagram of a phase change heat pump: 1) condenser coil, 2) expansion valve, 3) evaporator coil, 4) compressor. ...

This cycle takes advantage of the universal gas law PV = nRT, where P is pressure, V is volume, R is the universal gas constant, T is temperature, and n is the number of moles of gas (1 mole = 6.022×10²³ molecules). The ideal gas law, or universal gas equation, is an equation of state of an ideal gas. ... Molar gas constant (also known as universal gas constant, usually denoted by symbol R) is the constant occurring in the universal gas equation, i. ...

The most common refrigeration cycle uses an electric motor to drive a compressor. In an automobile the compressor is driven by a pulley on the engine's crankshaft, with both using electric motors for air circulation. Since evaporation occurs when heat is absorbed, and condensation occurs when heat is released, air conditioners are designed to use a compressor to cause pressure changes between two compartments, and actively pump a refrigerant around. A refrigerant is pumped into the cooled compartment (the evaporator coil), where the low pressure and load temperature cause the refrigerant to evaporate into a vapor, taking heat with it. In the other compartment (the condenser), the refrigerant vapour is compressed and forced through another heat exchange coil, condensing into a liquid, rejecting the heat previously absorbed from the cooled space. A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. ... Pulleys on a ship. ... Crankshaft, pistons, and flywheel Continental engine marine crankshafts, 1942 For the comic strip about an old, curmudgeonly bus driver, see Crankshaft (comic strip). ... Water vapor condensing over a cup of hot tea Evaporation is one of the two forms of vaporization. ... In physics, heat is defined as energy in transit. ... Condensation is the change in matter1 of a substance to a denser phase, such as a puppy gas (or vapor) to a liquid. ...

Humidity

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. Humidity is the concentration of water vapor in the air. ... 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. ... Water vapor condensing over a cup of hot tea Evaporation is one of the two forms of vaporization. ...

Some air conditioning units dry the air without cooling it. They work like a normal air conditioner, except that a heat exchanger is placed between the intake and exhaust. In combination with convection fans they achieve a similar level of comfort as an air cooler in humid tropical climates, but only consume about 1/3 of the electricity. They are also preferred by those who find the draft created by air coolers discomforting. A heat exchanger is a device built for efficient heat transfer from one fluid to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are directly contacted. ... Non-electric fan Household Electric Fan Fans have had several purposes, the most common being to move air for creature comfort or for ventilation and to move air or gas from one location to another for industrial purposes. ... Swamp coolers (also called evaporative coolers or Air coolers) are air conditioners used to cool buildings in dry climates. ...

Refrigerants

"Freon" is a trade name for a family of haloalkane refrigerants manufactured by DuPont and other companies. These refrigerants were commonly used due to their superior stability and safety properties. Unfortunately, evidence has accumulated that these chlorine bearing refrigerants reach the upper atmosphere when they escape. The chemistry is poorly understood but general consensus seems to be that CFCs break up in the stratosphere due to UV-radiation, releasing their chlorine atoms. These chlorine atoms act as catalysts in the breakdown of ozone, which does severe damage to the ozone layer that shields the Earth's surface from the strong UV radiation. The chlorine will remain active as a catalyst until and unless it binds with another particle forming a stable molecule. CFC refrigerants in common but receding usage include R-11 and R-12. Newer and more environmentally-safe refrigerants include HCFCs (R-22, used in most homes today) and HFCs (R-134a, used in most cars) have replaced most CFC use. HCFCs in turn are being phased out under the Montreal Protocol and replaced by hydrofluorocarbons (HFCs), such as R-410A, which lack chlorine. The haloalkanes (also known as halogenoalkanes) are a group of chemical compounds, consisting of alkanes, such as methane or ethane, with one or more halogens linked, such as chlorine or fluorine, making them a type of organic halide. ... The haloalkanes (also known as halogenoalkanes) are a group of chemical compounds, consisting of alkanes, such as methane or ethane, with one or more halogens linked, such as chlorine or fluorine, making them a type of organic halide. ... Refrigeration (from the Latin frigus, frost) is generally the cooling of a body by the transfer of a portion of its heat away from it. ... This article is about the DuPont company. ... Atmosphere diagram showing stratosphere The stratosphere is a layer of Earths atmosphere that is stratified in temperature, with warmer layers higher up and cooler layers farther down. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... In chemistry, a catalyst (Greek: καταλύτης, catalytēs) is a substance that decreases the activation energy of a chemical reaction (see also catalysis) without itself being changed at the end of the chemical reaction. ... The ozone layer, or ozonosphere layer (rarely used term), is that part of the Earths atmosphere which contains relatively high concentrations of ozone (O3). ... The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of a number of substances believed to be responsible for ozone depletion. ...

Air conditioning system equipment

Evaporation coolers

Main article: Swamp cooler

The aforementioned Persian cooling systems were evaporation coolers. In very dry climates, so-called "swamp coolers" are popular for improving comfort during hot weather. The evaporative cooler is a device that draws outside air through a wet pad. The sensible heat of the incoming air, as measured by a dry bulb thermometer, is reduced. The total heat (sensible heat plus latent heat) of the entering air is unchanged. Some of the sensible heat of the entering air is converted to latent heat by the evaporation of water in the wet cooler pads. If the entering air is dry enough, the results can be quite comfortable. These coolers cost less and are mechanically simple to understand and maintain. Swamp coolers (also called evaporative coolers or Air coolers) are air conditioners used to cool buildings in dry climates. ... Swamp coolers (also called evaporative coolers or Air coolers) are air conditioners used to cool buildings in dry climates. ... Weather is an all-encompassing term used to describe all of the many and varied phenomena that can occur in the atmosphere of a planet. ... Sensible heat is heat that is transported by a body that has a temperature higher than its surroundings. ... The dry-bulb temperature is the temperature of air measured by a thermometer freely exposed to the air but shielded from radiation and moisture. ... Sensible heat is heat that is transported by a body that has a temperature higher than its surroundings. ... Latent heat describes the amount of energy in the form of heat that is required for a material to undergo a change of phase (also known as change of state). Two latent heats are typically described. ...

An early type of cooler, using ice for a further effect, was patented by John Gorrie of Apalachicola, FL in 1842, who used the device to cool the patients of his malaria hospital. 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. ... The mouth of the Apalachicola River, looking towards the Bay. ... Malaria (Medieval Italian: mala aria — bad air) and formerly called ague or marsh fever in English, is an infectious disease which causes about 350–500 million infections in humans and approximately 1. ...

There is a process called absorptive refrigeration which uses heat to produce cooling. In one instance, a three-stage absorptive cooler first dehumidifies the air with a spray of salt-water or brine. The brine osmotically absorbs water vapor from the air. The second stage sprays water in the air, cooling the air by evaporation. Finally, to control the humidity, the air passes through another brine spray. The brine is reconcentrated by distillation. The system is used in some hospitals because, with filtering, a sufficiently hot regenerative distillation removes airborne organisms. Absorptive refrigeration utilizes a source of heat to provide the energy needed to drive the cooling process. ... Absorptive refrigeration utilizes a source of heat to provide the energy needed to drive the cooling process. ... Brine is water saturated or nearly saturated with salt. ... Osmosis is the diffusion of a liquid (most often assumed to be water, but it can be any liquid solvent) through a partially-permeable membrane from a region of low solvent potential to a region of high solvent potential. ...

Absorptive chillers

Some buildings use gas turbines to generate electricity. The exhausts of these are hot enough to drive an absorptive chiller that produces cold water. The cold water is then run through radiators in air ducts for hydronic cooling. The dual use of the energy, both to generate electricity and cooling, makes this technology attractive when regional utility and fuel prices are right. Producing heat, power, and cooling in one system is known as trigeneration. This article needs to be wikified. ... Trigeneration implies the simultaneous production of mechanical power (electricity), heat and cooling from a single fuel. ...

Portable air conditioners

A portable air conditioner or portable A/C is an air conditioner on wheels, that can be easily transported inside the house or office. They are currently commercially produced and sold in the U.S. with capacities of 6000 to 14000 BTU/h (1800 to 4100 watts output), with and without heaters, by companies like EdgeStar, DeLonghi, Sunpentown, Fujitronic and others.

Portable A/C comes in two forms, split and monoblock (has one or two 4” or 6” air ducts which are vented to outside). The single duct monoblock unit is often ineffective because air is pumped out of the room, this air is then replaced by hot air from outside reducing efficiency, simply attach a box to the back of the unit where the air is drawn over the condenser and buy some additional ducting and you have converted your unit to twin pipe, this will be able to build up a much greater temperature difference than a single pipe unit. Cooling power figures should be regarded suspiciously; it is best to look at the input power and the heat transfer figures. For example, a 1350W unit will generally give a 3 kW heat transfer. Twin pipe mode will reduce the initial efficiency (see Carnot cycle, efficiency = T_L/(T_H-T_L)) as T_H has increased (assuming outdoors is hotter than indoors) but the obvious benefit of greater temperature difference will mean the unit doesn’t need to run continually so efficiency will increase. Avoid units using R-22 as it is ozone depleting and the less efficient ones using R407c. Best choice would be a unit using R-410a gas, also known as Puron that is ozone-friendly and allows a higher efficiency. A heat engine is an engine that uses heat to produce mechanical work by carrying a working substance through a cyclic process. ... For other uses, see Ozone (disambiguation). ... R-410A is an azeotropic mixture of difluoromethane and pentafluoroethane which is used as a refrigerant in air conditioning applications. ... R-410A is an azeotropic mixture of difluoromethane and pentafluoroethane which is used as a refrigerant in air conditioning applications. ...

When selecting a new portable air conditioner it is very impotant to select one with the proper cooling capacity for the room you are trying to cool. Use this simple air conditioner sizing calculator to help with your window air conditioner or portable air conditioner selection.

Central air conditioning

Central air conditioning, commonly referred to as central air (US) or air-con (UK), is an air conditioning system which uses ducts to distribute cooled and/or dehumidified air to more than one room, or uses pipes to distribute chilled water to heat exchangers in more than one room, and which is not plugged into a standard electrical outlet. CEE 7/7 plug and socket Domestic AC power plugs and sockets allow a connection between the mains (domestic, usually single-phase, AC electrical power) and the appliances commonly used in homes. ...

With a typical split system, the condenser and compressor are located in an outdoor unit; the evaporator is mounted in the air handling unit (which is often a forced air furnace). With a package system, all components are located in a single outdoor unit that may be located on the ground or roof. The term condenser has the following meanings: In electronics, it is another (old-fashioned) word for capacitor. ... A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. ... Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state. ...

Central air conditioning performs like a regular air conditioner but has several added benefits: Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ...

• When the air handling unit turns on, room air is drawn in from various parts of the house through return-air ducts. This air is pulled through a filter where airborne particles such as dust and lint are removed. Sophisticated filters may remove microscopic pollutants as well. The filtered air is routed to air supply ductwork that carries it back to rooms. Whenever the air conditioner is running, this cycle repeats continually.

• Because the central air conditioning unit is located outside the home, it offers a lower level of noise indoors than a free-standing air conditioning unit.

The term filter may refer to: A device to separate mixtures. ... In physics, a particle is an object, or body, with only a few degrees-of-freedom, including position, and perhaps orientation in space. ... Pollutants are substances which directly or indirectly damage us or the environment. ...

Absorption and solar air conditioning

Thermostats

Thermostats control the operation of HVAC systems, turning on the heating or cooling systems to bring the building to the set temperature. Typically the heating and cooling systems have separate control systems (even though they may share a thermostat) so that the temperature is only controlled "one-way". That is, in winter, a building that is too hot will not be cooled by the thermostat. Thermostats may also be incorporated into facility energy management systems in which the power utility customer may control the overall energy expenditure. In addition, a growing number of power utilities have made available a device which, when professionally installed, will control or limit the power to an HVAC system during peak use times in order to avoid necessitating the use of rolling blackouts. The customer is given a credit of some sort in exchange. Bi-metallic thermostat for buildings A thermostat is a device for maintaining the temperature of a system within a range by controlling, either directly or indirectly, the flow of heat energy into or out of the system. ... Bi-metallic thermostat for buildings A thermostat is a device for maintaining the temperature of a system within a range by controlling, either directly or indirectly, the flow of heat energy into or out of the system. ... A public utility is a company that maintains the infrastructure for a public service. ... Rolling blackout refers to an intentionally-engineered electrical power outage, caused by insufficient available resources to meet prevailing demand for electricity. ...

Equipment Capacity

Air conditioner equipment power in the U.S. is often described in terms of "tons of refrigeration". A "ton of refrigeration" is defined as the cooling power of one short ton (2000 pounds or 907 kilograms) of ice melting in a 24-hour period. This is equal to 12,000 BTU per hour, or 3517 watts (http://physics.nist.gov/Pubs/SP811/appenB9.html). Residential "central air" systems are usually from 1 to 5 tons (3 to 20 kW) in capacity. 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... The short ton is a unit of mass equal to 907. ... The pound is the name of a number of units of mass, all in the range of 300 to 600 grams. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... The acronym ICE can refer to: InterCity Express, a German high-speed train InterCity Express (CityTrain), an interurban train used by QR CityTrain in South East Queensland, Australia Internal combustion engine, a fuel engine In-circuit emulator, a computer hardware device In case of emergency, emergency number in mobile phones... The British thermal unit (BTU) is a non-metric unit of energy, used in the United States and, to a certain extent, the UK. The SI unit is the joule (J), which is used by most other countries. ... The hour (symbol: h) is a unit of time. ... The watt (symbol: W) is the SI derived unit of power. ... Central air conditioning, commonly referred to as central air, is an air conditioning system which uses ducts to distribute cooled and/or dehumidified air to more than one room, or uses pipes to distribute chilled water to heat exchangers in more than one room, and which is not plugged into...

The use of electric/compressive air conditioning puts a major demand on the nation's electrical power grid in warm weather, when most units are operating under heavy load. In the aftermath of the 2003 North America blackout locals were asked to keep their air conditioning off. During peak demand, additional power plants must often be brought online, usually natural gas fired plants because of their rapid startup. A 1995 study of various utility studies of residential air conditioning concluded that the average air conditioner wasted 40% of the input energy. This energy is lost in the form of heat, which must be pumped out. There is a huge opportunity to reduce the need for new power plants and to conserve energy. Description of an electrical power grid Electrical power is generated in many locations and created by various technologies in the form of alternating current. ... The 2003 North America blackout was a massive power outage that occurred throughout parts of the northeastern United States and eastern Canada on Thursday, August 14, 2003. ... A power station (also power plant) is a facility for the generation of electric power. ... Many stoves use natural gas. ... 1995 (MCMXCV) was a common year starting on Sunday of the Gregorian calendar. ...

In an automobile the A/C system will use around 5 hp (4 kW) of the engine's power. The horsepower (hp) is the name of several non-metric units of power. ... In physics, power (symbol: P) is the amount of work done per unit of time. ...

The Association of Home Appliance Manufacturers (AHAM) offers a worksheet that can help you estimate how powerful an air conditioner you need. The worksheet guides you through the measurements needed to calculate the size of the air conditioner, and then it automatically calculates the final answer for you. The Association of Home Appliance Manufacturers or AHAM represents the manufacturers of household appliances and products/services associated with household appliances sold in the United States. ... The Ahoms ruled parts of present-day Assam (in India) for nearly 600 years: from 1228 to 1826. ...

Seasonal Energy Efficiency Rating (SEER)

For residential homes, some countries set minimum requirements for energy efficiency. The efficiency of air conditioners are often (but not always) rated by the Seasonal Energy Efficiency Ratio (SEER). The higher the SEER rating, the more energy efficient is the air conditioner. The SEER rating is 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. ^[1] Seasonal Energy Efficiency Ratio (SEER) is a measurement of efficiency for cooling devices such as heat pumps and air conditioners. ... The British thermal unit (BTU) is a non-metric unit of energy, used in the United States and, to a certain extent, the UK. The SI unit is the joule (J), which is used by most other countries. ... The watt (symbol: W) is the SI derived unit of power. ...

SEER = BTU ÷ W·h

For example, a 5000 Btu/h air-conditioning unit, with a SEER of 10, operating for a total of 1000 hours during an annual cooling season (i.e., 8 hours per day for 125 days) would provide an annual total cooling output of:

1000 Btu/h × 5000 h = 5,000,000 Btu

which, for a SEER of 10, would be an annual electrical energy usage of:

5,000,000 Btu ÷ 10 = 500,000 W·h

and that is equivalent to an average power usage during the cooling season of:

500,000 W·h ÷ 1000 h = 500 W

SEER is related to the coefficient of performance (COP) commonly used in thermodynamics and also to the Energy 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). The COP is different in that it is a unitless parameter. Formulas for the approximate conversion between SEER and EER or COP are available from the Pacific Gas and Electric company in California:^[2] 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. ... ‹ The template below has been proposed for deletion. ...

(1)     SEER = EER ÷ 0.9

(2)     SEER = COP x 3.792

(3)     EER = COP x 3.413

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

Today, it is rare to see systems rated below SEER 9 in the United States, since older units are being replaced with higher efficiency units. The United States now requires that residental 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).^[3] Substantial energy savings can be obtained from more efficient systems. For example by upgrading from SEER 9 to SEER 13, the power consumption is reduced by 30% (equal to 1 - 9/13). It is claimed that this can result in an energy savings valued at up to $US 300 per year (depending on the usage rate and the cost of electricity). In many cases, the lifetime energy savings is likely to surpass the higher initial cost of a high-efficiency unit.

As an example, the annual cost of electric power consumed by a 72,000 BTU/h air conditioning unit operating for 1000 hours per year with a SEER rating of 10 and a power cost of $0.08 per kilowatt-hour (kW·h) may be calculated as follows: The British thermal unit (BTU) is a non-metric unit of energy, used in the United States and, to a certain extent, the UK. The SI unit is the joule (J), which is used by most other countries. ...

unit size, BTU/h × hours per year, h × power cost, $/kW·h ÷ (SEER, BTU/W·h × 1000 W/kW)

(72,000 BTU/h) × (1000 h) × ($0.08/kW·h) ÷ [(10 BTU/W·h) × (1000 W/kW)] = $576.00 annual cost

Air conditioner sizes are often given as "tons" of cooling. Multiplying the tons of cooling by 12,000 converts it to BTU/h. The word ton or tonne is derived from the Old English tunne, and ultimately from the Old French tonne, and referred originally to a large cask with a capacity of 252 wine gallons, which holds approximately 2100 pounds of water. ...

A common misconception is that the SEER rating system also applies to heating systems. However, SEER ratings only apply to air conditioning.

Air conditioners (for cooling) and heat pumps (for heating) both work similarly in that heat is transferred or "pumped" from a cooler "heat-source" to a warmer "heat-sink". Air conditioners and heat pumps usually operate most effectively at temperatures around 50 to 55 degrees Fahrenheit. Typically when the heat source temperature falls below 40 degrees Fahrenheit, the system begins to reach a point called the "balance point", where the system is not able to "pull" any more heat out of the heat-source (this point varies from heat pump to heat pump). Similarly, when the heat-sink temperature rises to about 120 degrees Fahrenheit, the system will operate less effectively, and will not be able to "push" out any more heat. Ground-source (geothermal) heat pumps don't have this problem of reaching a "balance point" because they use the ground as a heat source/heat sink and the ground's thermal inertia prevents it from becoming too cold or too warm when moving heat from or to it. The ground's temperature does not vary nearly as much over a year as the air above it does. A diagram of a phase change heat pump: 1) condenser coil, 2) expansion valve, 3) evaporator coil, 4) compressor. ... A large copper heatsink. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ...

Insulation

Insulation reduces the required power of the air conditioning system. Thick walls, reflective roofing material, curtains and trees next to building also cut down on system and energy requirements. Insulation must not be confused with insolation (the latter word has an o where the former has a u). Insulation is any material used to reduce or “slow down” or “resist” the flow of energy. ...

Home air conditioning systems around the world

Domestic air conditioning is most prevalent and ubiquitous in developed Asian nations such as Japan, South Korea, Singapore and Hong Kong, especially in the latter two due to most of the population living in small high-rise flats. In this area, with soaring summer temperatures and a high standard of living, air conditioning is considered a necessity and not a luxury. Japanese-made domestic air conditioners are usually window or split types, the latter being more modern and expensive. It is also increasing in popularity with the rising standard of living in tropical Asian nations such as India, Malaysia and the Philippines. An apartment estate in Singapore, which makes up the majority of public housing in Singapore. ...

In the United States, home air conditioning is more prevalent in the South and on the East Coast, in most parts of which it has reached the ubiquity it enjoys in East Asia. Central air systems are most common in the United States, and are virtually standard in all new dwellings in most states.

In Europe, home air conditioning is less common in part due to higher energy costs. The lack of air conditioning in homes, in residential care homes and in medical facilities was identified as a contributing factor to the estimated 35,000 deaths left in the wake of the 2003 heat wave. World map showing Europe Political map Europe is one of the seven continents of Earth which, in this case, is more a cultural and political distinction than a physiographic one, leading to various perspectives about Europes borders. ... The summer of 2003 was one of the hottest ever in Europe; this led to a health crisis in certain countries as well as considerable impact on crops. ...

Health implications

Air conditioning has no greater influence on health than heating—that is to say, very little—although poorly maintained air-conditioning systems (especially large, centralized systems) can occasionally promote the growth and spread of microorganisms, such as Legionella pneumophila, the infectious agent responsible for Legionnaire's disease, or thermophilic actinomycetes.^[4] 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.^[5] Legionellosis is an infection caused by species of the bacterium Legionella, most notably . ... Legionellosis is an infection caused by species of the bacterium Legionella, most notably . ... Actinomycetales, commonly referred to as Actinomycetes, is an order of bacteria in the class Actinobacteria. ... Look up hypoallergenic in Wiktionary, the free dictionary. ... An allergy can refer to several kinds of immune reactions including Type I hypersensitivity in which a persons body is hypersensitised and develops IgE type antibodies to typical proteins. ...

Although many people superstitiously believe that air conditioning is unconditionally dangerous for one's health, especially in areas where air conditioning is not common, this belief is unsupported by fact; properly maintained air-conditioning systems do not cause or promote illness. As with heating systems, the advantages of air conditioning generally far outweigh the disadvantages.

References

1. ^ Definition of SEER (scroll down to "Seasonal energy efficiency ratio")
2. ^ SEER conversion formulas from Pacific Gas and Electric
3. ^ Minimum SEER ratings required in the US
4. ^ Sick building syndrome
5. ^ Home Control of Asthma & Allergies

See also

• Air filter
• Energy
• Energy conservation
• Heat pump
• Heating
• HVAC
• Hydronics
• Noise mitigation
• Renewable energy
• Refrigeration
• Trigeneration

It has been suggested that this article or section be merged with air cleaner. ... For the physical concepts, see conservation of energy and energy efficiency. ... A diagram of a phase change heat pump: 1) condenser coil, 2) expansion valve, 3) evaporator coil, 4) compressor. ... Heating may refer to: Heating, ventilation and air-conditioning. ... HVAC (pronounced either H-V-A-C or, occasionally, H-VAK) is an initialism/acronym that stands for heating, ventilating and air-conditioning. This is sometimes referred to as climate control. ... Name for heating and cooling systems using water as the circulated heat exchange medium. ... Roadway noise is the most pervasive form of environmental noise Noise mitigation is a set of strategies to reduce unwanted environmental sound. ... Renewable energy (sources) or RES capture their energy from existing flows of energy, from on-going natural processes, such as sunshine, wind, flowing water (hydropower), biological processes such as anaerobic digestion, and geothermal heat flow. ... It has been suggested that Refrigerator be merged into this article or section. ... Trigeneration implies the simultaneous production of mechanical power (electricity), heat and cooling from a single fuel. ...

External links

• Design failings of monoblock portable A/C

Servicing Information

• Directory of Air Conditioning Manufacturers

Energy Efficiency

• Consumer Guide to Home Energy Savings - Central Air Conditioners from the American Council for an Energy Efficient Economy (ACEEE)
• Energy Efficiency Program Database from the ACEEE
• Space heating and cooling from the U.S. Department of Energy's Energy Efficiency and Renewable Energy
• UK Enhanced Capital Allowance Scheme (ECA), a UK Government scheme to provide tax rebates for companies who use products which are ECA approved.
• International Energy Agency - Energy Conservation In Buildings And Community Systems
• AHAM website on Room-air Conditioners
• Top-Rated Energy-Efficient Central Air Conditioners
• Energy Star Central Air Conditioners
• How to lower the energy usage of central air conditioningen:Air conditioning