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. Its purpose, in the home or in the car, is to provide comfort during either hot or cold weather. 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). ... A mechanism is some technical aspect of a larger process or mechanical device, a part or combination of parts designed to perform a particular function. ... Ventilation good and very bad Ventilation is air circulation of air, typically between a room, a tunnel, etc. ... 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...

History

Main article: Air conditioning#History

Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ...

Air conditioning applications

Main article: Air conditioning#Air conditioning applications

Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ...

Air conditioning system basics and theories

Refrigeration cycle

A simple stylized 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 heat pump is a machine or device that moves heat from one location (the source) to another location (the sink), using work. ...

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 belt over a pulley, the belt being driven by the engine's crankshaft (similar to the driving of the pulleys for the alternator, power steering, etc.). Whether in a car or the house, both use electric fan 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 condense and pump a refrigerant around. A refrigerant is pumped into the cooled compartment (the evaporator coil), where the low pressure and low temperature cause the refrigerant to evaporate into a vapor, taking heat with it. In the other compartment (the condenser), the refrigerant vapor 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. ... For the band, see Pulley (band). ... Crankshaft (red), pistons (gray) in their cylinders (blue), and flywheel (black) Continental engine marine crankshafts, 1942 Components of a typical, four stroke cycle, DOHC piston engine. ... Vaporization redirects here. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... For other uses, see Condensation (disambiguation). ...

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. 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. ...

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 uncomfortable. 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. ... For other uses, see Fan. ... Swamp coolers (also called evaporative coolers or Air coolers) are air conditioners used to cool buildings in dry climates. ...

Refrigerants

Main article: 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. 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. ... Tetrafluoroethane (a haloalkane) is a clear liquid which boils well below room temperature (as seen here) and can be extracted from common canned air canisters by simply inverting them during use. ... Tetrafluoroethane (a haloalkane) is a clear liquid which boils well below room temperature (as seen here) and can be extracted from common canned air canisters by simply inverting them during use. ... 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 E.I. du Pont de Nemours and Company. ... This article is about the stratosphere layer; for the hotel in Las Vegas, Nevada, see Stratosphere Las Vegas. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... It has been suggested that this article or section be merged into Catalysis. ... The ozone layer is a layer in Earths atmosphere which contains relatively high concentrations of ozone (O3). ... Hydrochlorofluorocarbons (HCFCs) is one of a class of fluorocarbon compounds that are used primarily as chlorofluorocarbon (CFC) substitutes. ... Cl | F--C--F | H Chlorodifluoromethane or difluoromonochloromethane is a hydrochlorofluorocarbon (HCFC) with chemical formula CHClF2 and CAS number 75-45-6. ... HFC may stand for: Hydrofluorocarbon Hybrid Fibre Coaxial Highly Flamible Cow Cow is a communist from Romania who cant tell the difference between a pound and a euro. ... 1,1,1,2-Tetrafluoroethane, also called simply tetrafluoroethane or R-134a, is a refrigerant that has zero ozone depletion potential and thermodynamic properties similar to R-12. ... The largest Antarctic ozone hole recorded as of September 2006 For other similarly-named agreements, see Montreal Convention (disambiguation). ... R-410A is an azeotropic mixture of difluoromethane and pentafluoroethane which is used as a refrigerant in air conditioning applications. ... General Name, symbol, number chlorine, Cl, 17 Chemical series nonmetals Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ...

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.

A modern Americool window air-conditioner internal section

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. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Types of air conditioner equipment

Window and through-wall units

Many traditional air conditioners in homes or other buildings are single rectangular units used to cool an apartment, a house or part of it, or part of a building. For an example, see the photos to the right. Hotels frequently use PTAC systems, which combine heating into the same unit. Air conditioner units need to have access to the space they are cooling (the inside) and a heat sink; normally outside air is used to cool the condenser section. For this reason, single unit air conditioners are placed in windows or through openings in a wall made for the air conditioner; the latter type includes portable air conditioners.^[1] This article is about the structure. ...

Window and through-wall units have vents on both the inside and outside, so inside air to be cooled can be blown in and out by a fan in the unit, and outside air can also be blown in and out by another fan to act as the heat sink. The controls are on the inside.

A large house or building may have several such units. Should virtually every room be cooled with its own air conditioning unit, most of the day, it would be less expensive to use central air conditioning, though that may not be physically possible.

Evaporative coolers

Main article: Evaporative cooler

In very dry climates, evaporative coolers (or "swamp coolers") are popular for improving comfort during hot weather. This type of cooler is the dominant cooler used in Iran which has the largest number of units of any country in the world, hence some referring to them as Persian coolers^[2]. An evaporative cooler is a device that draws outside air through a wet pad, such as a large sponge soaked with water. 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. Evaporative coolers (also called air, swamp, or desert coolers) devices which use simple evaporation of water in air. ... For other uses, see Weather (disambiguation). ... Motto: Esteqlāl, āzādÄ«, jomhÅ«rÄ«-ye eslāmÄ« 1 Independence, freedom, Islamic Republic Anthem: SorÅ«d-e MellÄ«-e Īrān Â² Capital (and largest city) Tehran Official languages Persian, Constitutional status for regional languages such as Azeri and Kurdish [1] Demonym Iranian Government Islamic Republic  -  Supreme Leader  -  President... Sensible heat is heat energy that is transported by a body that has a temperature higher than its surroundings via conduction, convection, or both. ... 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 energy that is transported by a body that has a temperature higher than its surroundings via conduction, convection, or both. ... In thermochemistry, latent heat is the amount of energy in the form of heat released or absorbed by a substance during a change of phase (i. ...

An early type of cooler, using ice for a further effect, was patented by John Gorrie of Apalachicola, Florida in 1842. He used the device to cool the patients in 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 is a vector-borne infectious disease caused by protozoan parasites. ...

There is a related, more complex 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. ... For the sports equipment manufacturer, see Brine, Corp. ... Osmosis is the spontaneous net movement of water across a semipermeable membrane from a region of low solute concentration to a solution with a high solute concentration, down a solute concentration gradient. ...

Absorptive chillers

Main article: Absorptive chiller

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. ... This article needs to be wikified. ... Trigeneration implies the simultaneous production of mechanical power (often converted to electricity), heat and cooling from a single heat source such as solar energy or fuel. ...

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. Look up condenser in Wiktionary, the free dictionary. ... A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...

Central air conditioning performs like a regular air conditioner but has several added benefits:

• When the air handling unit turns on, room air is drawn in from various parts of the building 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.

An air filter is a device which cleans dirty air. ... Look up dust in Wiktionary, the free dictionary. ... Pollutants are substances which directly or indirectly damage us or the environment. ...

Thermostats

Main article: Thermostat

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, so it is often to the advantage of the consumer to buy the most efficient thermostat possible. Bi-metallic thermostat for buildings A thermostat is a device for regulating the temperature of a system so that the systems temperature is maintained near a desired setpoint temperature. ... Bi-metallic thermostat for buildings A thermostat is a device for regulating the temperature of a system so that the systems temperature is maintained near a desired setpoint temperature. ... Bi-metallic thermostat for buildings A thermostat is a device for regulating the temperature of a system so that the systems temperature is maintained near a desired setpoint temperature. ... 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. For other uses of terms redirecting here, see US (disambiguation), USA (disambiguation), and United States (disambiguation) Motto In God We Trust(since 1956) (From Many, One; Latin, traditional) Anthem The Star-Spangled Banner Capital Washington, D.C. Largest city New York City National language English (de facto)1 Demonym American... The short ton is a unit of mass equal to 907. ... Look up pound in Wiktionary, the free dictionary. ... Kg redirects here. ... This article is about water ice. ... 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. ... For other uses, see Watt (disambiguation). ... 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. ... For other uses, see Natural gas (disambiguation). ... Year 1995 (MCMXCV) was a common year starting on Sunday. ...

In an automobile the A/C system will use around 5 hp (4 kW) of the engine's power. This article is about a unit of measurement. ... In physics, power (symbol: P) is the rate at which work is performed or energy is transmitted, or the amount of energy required or expended for a given unit of time. ...

Seasonal Energy Efficiency Rating (SEER)

Main article: Seasonal Energy Efficiency Rating

For residential homes, some countries set minimum requirements for energy efficiency. In the United States, the efficiency of air conditioners is 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. ^[3] 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. ... For other uses, see Watt (disambiguation). ...

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:

5000 BTU/h × 1000 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). SEER is unusual in that it is composed of an Imperial unit divided by a metric unit. The COP is a ratio with the same metric units of energy (joules) in both the numerator and denominator. They cancel out leaving a dimensionless quantity. Formulas for the approximate conversion between SEER and EER or COP are available from the Pacific Gas and Electric company in California:^[4] 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. ... Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dynamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... The efficiency of air conditioners are often (but not always) rated by the Seasonal Energy Efficiency Ratio (SEER). ... The Imperial units are an irregularly standardized system of units that have been used in the United Kingdom and its former colonies, including the Commonwealth countries. ... The International System of Units (symbol: SI) (for the French phrase Système International dUnités) is the most widely used system of units. ... In the physical sciences, a dimensionless number (or more precisely, a number with the dimensions of 1) is a quantity which describes a certain physical system and which is a pure number without any physical units; it does not change if one alters ones system of units of measurement...

(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 residential systems manufactured in 2006 have a minimum SEER rating of 13 (although window-box systems are exempt from this law, so their SEER is still around 10).^[5] 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 are 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. Look up ton in Wiktionary, the free dictionary. ...

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 °F (10−13 °C). A 'balance point' is reached when the heat source temperature falls below about 40 °F (4 °C), and the system is not able to pull any more heat from the heat-source. (This point varies from heat pump to heat pump). Similarly, when the heat-sink temperature rises to about 120 °F (49 °C), the system will operate less effectively, and will not be able to 'push' out any more heat. Ground-source (geothermal) heat pumps do not 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 heat pump is a machine or device that moves heat from one location (the source) to another location (the sink), using work. ... This article is about the substance or device. ... For other uses, see Fahrenheit (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ...

Insulation

Insulation reduces the required power of the air conditioning system. Thick walls, reflective roofing material, curtains, and trees next to buildings also cut down on system and energy requirements. Wikimedia Commons has media related to: Thermal insulation Thermal insulation on the Huygens probe Rockwool Insulation, 1600 dpi scan against the grain Rockwool Insulation, 1600 dpi scan with the grain The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and...

Home air conditioning systems around the world

Domestic air conditioning is most prevalent and ubiquitous in developed Asian nations such as Japan, Taiwan, 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 Thailand, India, Malaysia and the Philippines. In Indonesia, an air-conditioning set is a must in every home due to the high temperature.^{[citation needed]} This article is about the structure. ...

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 generally less common in part due to higher energy costs and more moderate summer temperatures. Some European countries like Switzerland even forbid installation without permission, motivating that these devices use lots of energy and are environmentally unfriendly. Southern European countries, such as Greece, on the other hand, have seen a wide proliferation of home air-conditioning units in the past few years[1]. 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. For other uses, see Europe (disambiguation). ... 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.^[6] 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.^[7] 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 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. ... 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. ...

Properly maintained air-conditioning systems do not directly cause or promote illness, despite superstitions that air-conditioning is unconditionally dangerous to one's health. However, they may indirectly lead to air pollution if the electricity required to power them is produced from fossil fuels. Air pollution is the modification of the natural characteristics of the atmosphere by a chemical, particulate matter, or biological agent. ... Fossil fuels or mineral fuels are fossil source fuels, that is, hydrocarbons found within the top layer of the earth’s crust. ...

References

1. ^ Melonyce McAfee, "Coolin' the Gang: Which portable air conditioner works best?", Salon magazine, August 7, 2007
2. ^ History of Air Conditioning Source: Jones Jr., Malcolm. "Air Conditioning". Newsweek. Winter 1997 v130 n24-A p42(2). Retrieved 1 January 2007.
3. ^ Definition of SEER (scroll down to "Seasonal energy efficiency ratio")
4. ^ SEER conversion formulas from Pacific Gas and Electric
5. ^ Minimum SEER ratings required in the US
6. ^ Sick building syndrome
7. ^ Home Control of Asthma & Allergies

is the 1st day of the year in the Gregorian calendar. ...

See also

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

Air filter in an Opel Astra car, top side=clean side Air filter in an Opel Astra car, bottom side=dust side Automotive air filter clogged with dust and debris. ... A dehumidifier is a household appliance that reduces the level of humidity in the air. ... For the physical concepts, see conservation of energy and energy efficiency. ... A heat pump is a machine or device that moves heat from one location (the source) to another location (the sink), using work. ... Heating may refer to: Heating, ventilation and air-conditioning. ... 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... Hydronics is the name for the use of water as the heat-transfer medium in heating and cooling systems. ... Noise mitigation is a set of strategies to reduce unwanted environmental sound. ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... 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. ... Trigeneration implies the simultaneous production of mechanical power (often converted to electricity), heat and cooling from a single heat source such as solar energy or fuel. ... A whole house fan is a type of fan installed in a house that is designed to pull cool air into the house. ...

External links

• How Air Conditioners Work.

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
• Top-Rated Energy-Efficient Central Air Conditioners