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Encyclopedia > HVAC
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"
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 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 top of rockwool.
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 top of rockwool.

HVAC (pronounced either "H-V-A-C" or, occasionally, "H-VAK") is an initialism/acronym that stands for "heating, ventilation, and air conditioning". HVAC is sometimes referred to as "climate control" and is particularly important in the design of medium to large industrial and office buildings such as sky scrapers and in marine environments such as aquariums, where humidity and temperature must all be closely regulated whilst maintaining safe and healthy conditions within. In certain regions (e.g., UK) the term "Building Services" is also used, but may also include plumbing and electrical systems. Refrigeration is sometimes added to the field's abbreviation as HVAC&R or HVACR, or ventilation is dropped as HACR (such as the designation of HACR-rated circuit breakers). International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... City lights viewed in a motion blurred exposure. ... Image File history File links Central_ventilation_tube2. ... Image File history File links Central_ventilation_tube2. ... A round duct connecting to a typical diffuser Ducts are used in heating, ventilation, and air conditioning (HVAC) to carry air - these include conditioned, fresh, stale, foul (toilet extract), and contaminated air (flue exhaust, fume extraction) - from place to place. ... Image File history File links Size of this preview: 800 × 581 pixelsFull resolution (4875 × 3540 pixel, file size: 1. ... Image File history File links Size of this preview: 800 × 581 pixelsFull resolution (4875 × 3540 pixel, file size: 1. ... International time/temperature curves used to run commercial furnaces for testing the Fire-resistance rating of passive fire protection systems, such as firestops, fire doors, wall and floor assemblies, etc. ... Sheets of stainless steel cover the Chrysler Building Thin sheets of gold leaf Sheet metal is simply metal formed into thin and flat pieces. ... For other uses, see Copper (disambiguation). ... PIPE can refer to PIPE (explosive) PIPE Networks Private Investment in Public Equity (PIPE) Physical Interface for PCI Express (PIPE) For other meanings, see also pipe. ... Perimeter slab edge building joint with incomplete firestop, between concrete floor and precast concrete facade. ... This article is about the construction material. ... Firestop after fire exposure during fire test in Tulsa, Oklahoma. ... Caulking - Wikipedia /**/ @import /w/skins-1. ... Mineral wool, means fibres made from minerals or metal oxides, be they synthetic or natural. ... Acronyms and initialisms are abbreviations formed from the initial letter or letters of words, such as NATO and XHTML, and are pronounced in a way that is distinct from the full pronunciation of what the letters stand for. ... It has been suggested that this article or section be merged with Backronym and Apronym (Discuss) Acronyms and initialisms are abbreviations, such as NATO, laser, and ABC, written as the initial letter or letters of words, and pronounced on the basis of this abbreviated written form. ... HVAC may also stand for High-voltage alternating current HVAC is an initialism that stands for heating, ventilation and air-conditioning. This is sometimes referred to as climate control. ... Return inlet (left)Supply outlet (right). ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... Taipei 101, the worlds tallest skyscraper by roof height on high rise. ... “Aquaria” redirects here. ... Sick building syndrome (SBS) is a combination of ailments (a syndrome) associated with an individuals place of work; typically, but not always, an office building (though there have also been instances of SBS in residential buildings). ... 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. ...


Heating, ventilation, and air conditioning is based on the basic principles of thermodynamics, fluid mechanics, and heat transfer, and to inventions and discoveries made by Michael Faraday, Willis Carrier, Reuben Trane, James Joule, William Rankine, Sadi Carnot, and many others. The invention of the components of HVAC systems goes hand-in-hand with the industrial revolution, and new methods of modernization, higher efficiency, and system control are constantly introduced by companies and inventors all over the world. 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. ... Fluid mechanics is the subdiscipline of continuum mechanics that studies fluids, that is, liquids and gases. ... In thermal physics, heat transfer is the passage of thermal energy from a hot to a cold body. ... 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 significantly to the fields of electromagnetism and electrochemistry. ... Willis Haviland Carrier (November 26, 1876 – October 7, 1950) was an engineer and inventor, and is known as the man who invented modern air conditioning. ... Reuben N. Trane (September 13, 1886 in La Crosse, Wisconsin - September 5, 1954 in La Crosse) founded Trane, the heating and air conditioning company, with his father James Trane. ... James Prescott Joule (December 24, 1818–October 11, 1889) was an English physicist, born in Salford, near Manchester. ... William John Macquorn Rankine (July 2, 1820 - December 24, 1872) was a Scottish engineer and physicist. ... Sadi Carnot in the dress uniform of a student of the École polytechnique Nicolas Léonard Sadi Carnot (June 1, 1796 - August 24, 1832) was a French physicist and military engineer who gave the first successful theoretical account of heat engines, now known as the Carnot cycle, thereby laying the...


The three functions of heating, ventilation, and air-conditioning are closely interrelated. All seek to provide thermal comfort, acceptable indoor air quality, and reasonable installation, operation, and maintenance costs. HVAC systems can provide ventilation, reduce air infiltration, and maintain pressure relationships between spaces. How air is delivered to, and removed from spaces is known as room air distribution.[1] Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ... Indoor Air Quality (IAQ) deals with the content of interior air that could affect health and comfort of building occupants. ... Return inlet (left)Supply outlet (right). ... Infiltration is the unintentional or accidential introduction of outside air into a building, typically through cracks in the building envelope and through use of doors for passage. ... Characterizing how air is introduced to, flows through, and is removed from spaces is called room air distribution. ...


In modern buildings the design, installation, and control systems of these functions are integrated into one or more HVAC systems. For very small buildings, contractors normally "size" and select HVAC systems and equipment. For larger buildings where required by law, "building services" designers and engineers, such as mechanical, architectural, or building services engineers analyze, design, and specify the HVAC systems, and specialty mechanical contractors build and commission them. In all buildings, building permits for, and code-compliance inspections of the installations are the norm. A control system is a device or set of devices that manage the behavior of other devices. ... Engineering is the application of scientific and technical knowledge to solve human problems. ... Mechanical Engineering is an engineering discipline that involves the application of principles of physics for analysis, design, manufacturing, and maintenance of mechanical systems. ... An architectural engineer applies the skills of many engineering disciplines to the design, construction, operation, maintenance, and renovation of buildings while paying attention to their impacts on the surrounding environment. ... // Building engineering: a discipline for the modern era Building engineering, commonly known in the US as architectural engineering, is an emerging engineering discipline that concerns with the planning, design, construction, operation, renovation, and maintenance of buildings, as well as with their impacts on the surrounding environment. ...


The HVAC industry is a worldwide enterprise, with career opportunities including operation and maintenance, system design and construction, equipment manufacturing and sales, and in education and research. The HVAC industry had been historically regulated by the manufacturers of HVAC equipment, but Regulating and Standards industries such as ASHRAE, SMACNA, ACCA, and AMCA, have been established to support the industry and encourage high standards and achievement. Most recently, the ICC has been established to create international standards that many countries, including the US, Canada, the UK, Australia and many others have been adopting. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) is an international voluntary organization for people involved in heating, ventilation, air conditioning, or refrigeration (HVAC&R). ... The Sheet Metal and Air Conditioning Contractors National Association (SMACNA; pronounced Smack-Nah) is an international association of union HVAC contractors. ... The Air Conditioning Contractors of America (ACCA) is the largest HVAC contractor organization in the USA. Its headquarters is at 2800 Shirlington Road, Suite 300 • Arlington, VA 22206. ... The Air Movement and Control Association International, Inc. ...

Contents

Heating

Heating systems may be classified as central or local. Central heating is often used in cold climates to heat private houses and public buildings. Such a system contains a boiler, furnace, or heat pump to heat water, steam, or air, all in a central location such as a furnace room in a home or a mechanical room in a large building. The system also contains piping or ductwork to distribute the heated fluid, and radiators to transfer this heat to the air. The term radiator in this context is misleading since most heat transfer from the heat exchanger is by convection, not radiation. The radiators may be mounted on walls or buried in the floor to give under-floor heat. For the Grand Central Records albums, see Central Heating (Grand Central album) and Central Heating 2. ... For the Grand Central Records albums, see Central Heating (Grand Central album) and Central Heating 2. ... A boiler is a closed vessel in which water or other fluid is heated under pressure. ... A furnace is a device for heating air or any other fluid. ... A diagram of a simple heat pumps vapor-compression refrigeration cycle: 1) condenser, 2) expansion valve, 3) evaporator, 4) compressor. ... Furnace room A Furnace room is a room for locating the furnace and auxillary equipment. ... Mechanical room in a large office building. ... Radiators and convectors are types of heat exchangers designed to transfer thermal energy from one medium to another for the purpose of cooling and heating. ... Convection in the most general terms refers to the internal movement of currents within fluids (i. ... “Radiant heat” redirects here. ...


In boiler fed or radiant heating systems, all but the simplest systems have a pump to circulate the water and ensure an equal supply of heat to all the radiators. The heated water can also be fed through another heat exchanger inside a storage cylinder to provide hot running water.


Forced air systems send heated air through ductwork. During warm weather the same ductwork can be reused for air conditioning. The forced air can also be filtered or put through air cleaners. Most ducts cannot fit a human being (as they do in many films) since this would require a greater duct-structural integrity and create a potential security liability. A round duct connecting to a typical diffuser Ducts are used in heating, ventilation, and air conditioning (HVAC) to carry air - these include conditioned, fresh, stale, foul (toilet extract), and contaminated air (flue exhaust, fume extraction) - from place to place. ...


Heating can also be provided from electric, or resistance heating using a filament that glows hot when you cause electricity to pass through it. This type of heat can be found in electric baseboard heaters, portable electric heaters, and as backup or supplemental heating for heat pump (or reverse heating) system.


The heating elements (radiators or vents) should be located in the coldest part of the room and typically next to the windows to minimize condensation. Popular retail devices that direct vents away from windows to prevent "wasted" heat defeat this design parameter. Drafts contribute more to the subjective feeling of coldness than actual room temperature. Therefore, rather than improving the heating of a room/building, it is often more important to control the air leaks.[citation needed]


The invention of central heating is often credited to the ancient Romans, who installed a system of air ducts called "hypocaust" in the walls and floors of public baths and private villas. The ducts were fed with hot air from a central fire. Generally, these heated by radiation; a better physiologic approach to heating than conventional forced air convective heating.[citation needed] For other uses, see Roman Empire (disambiguation). ... Ruins of the hypocaust under the floor of a Roman villa. ...


Ventilation

An air handling unit is used for the heating and cooling of air in a central location (click on image for legend).
An air handling unit is used for the heating and cooling of air in a central location (click on image for legend).

Ventilation is the process of "changing" or replacing of air in any space to remove moisture, odors, smoke, heat, dust and airborne bacteria. Ventilation includes both the exchange of air to the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/forced and natural types.[2] Ventilation is used to remove unpleasant smells and excessive moisture, introduce outside air, and to keep interior building air circulating, to prevent stagnation of the interior air. Image File history File linksMetadata Size of this preview: 800 × 532 pixel Image in higher resolution (1109 × 738 pixel, file size: 245 KB, MIME type: image/jpeg) Typical AHU components: 1 - Supply duct 2 - Fan compartment 3 - Vibration isolators 4 - Heating and/or cooling coil 5 - Filter compartment 6 - Return... Image File history File linksMetadata Size of this preview: 800 × 532 pixel Image in higher resolution (1109 × 738 pixel, file size: 245 KB, MIME type: image/jpeg) Typical AHU components: 1 - Supply duct 2 - Fan compartment 3 - Vibration isolators 4 - Heating and/or cooling coil 5 - Filter compartment 6 - Return... An air handling unit; air flow is from the right to left in this case. ... Return inlet (left)Supply outlet (right). ... Indoor Air Quality (IAQ) deals with the content of interior air that could affect health and comfort of building occupants. ...


Mechanical or forced ventilation

"Mechanical" or "forced" ventilation is used to control indoor air quality. Excess humidity, odors, and contaminants can often be controlled via dilution or replacement with outside air. But in humid climates, much energy is required to remove excess moisture from ventilation air. Indoor Air Quality (IAQ) deals with the content of interior air that could affect health and comfort of building occupants. ... Humidity is the amount of water vapor in air. ...


Kitchens and bathrooms typically have mechanical exhaust to control odors and sometimes humidity. Factors in the design of such systems include the flow rate (which is a function of the fan speed and exhaust vent size) and noise level. If the ducting for the fans traverse unheated space (e.g., an attic), the ducting should be insulated as well to prevent condensation on the ducting. Direct drive fans are available for many applications, and can reduce maintenance needs.


Heat recovery ventilation systems employ heat exchangers to recover some heat from exhausted air, to preheat the incoming outside air. Heat recovery ventilation is a ventilation system that employs a heat exchanger between the inbound and outbound air flow to save on energy required for heating (or cooling) the room. ...


Ceiling fans and table/floor fans are very effective in circulating air within a room. Counterintuitively, because hot air rises, ceiling fans may be used to keep a room warmer. Ceiling fans do not provide 'ventilation', however. Household Electric Fan A mechanical fan is a device used to produce an airflow for the purpose of creature comfort, ventilation, exhaust, or any other gaseous transport. ...


Natural ventilation

Natural ventilation is the ventilation of a building with outside air without the use of a fan or other mechanical system. It can be achieved with operable windows when the spaces to ventilate are small and the architecture permits. In more complex systems warm air in the building can be allowed to rise and flow out upper openings to the outside (stack effect) thus forcing cool outside air to be drawn into the building naturally through openings in the lower areas. These systems use very little energy but care must be taken to ensure the occupants' comfort. In warm or humid months, in many climates, maintaining thermal comfort via solely natural ventilation may not be possible so conventional air conditioning systems are used as backups. Air-side economizers perform the same function as natural ventilation, but use mechanical systems' fans, ducts, dampers, and control systems to introduce and distribute cool outdoor air when appropriate. Natural ventilation is the process of supplying and removing air through an indoor space by natural means. ... Stack effect is the ventilation in buildings and chimneys that results from thermal differences between indoor and outside temperature. ... Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... It has been suggested that this article or section be merged with Economiser. ...


Air-conditioning

Air Conditioning and refrigeration are provided through the removal of heat. The definition of cold is the absence of heat and all air conditioning systems work on this basic principle. Heat can be removed through the process of radiation, convection, and conduction using mediums such as water, air, ice, and special refrigerants sometimes referred to as freon, a member of the CFC family. In order to remove heat from something, you simply need to provide a medium that is colder -- this is how all air conditioning and refrigeration systems work. Radiation as used in physics, is energy in the form of waves or moving subatomic particles. ... Convection in the most general terms refers to the internal movement of currents within fluids (i. ... Heat conduction or thermal conduction is the spontaneous transfer of thermal energy through matter, from a region of higher temperature to a region of lower temperature, and hence acts to even out temperature differences. ... Freon is a trade name for a group of chlorofluorocarbons used primarily as a refrigerant. ... 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. ...


An air conditioning system, or a standalone air conditioner, provides cooling, ventilation, and humidity control for all or part of a house or building. The freon or other refrigerant provides cooling through a process called the refrigeration cycle. The refrigeration cycle consists of four essential elements to create a cooling effect. A compressor provides compression for the system. This compression causes the cooling vapor to heat up. The compressed vapor is then cooled by heat exchange with the outside air, so that the vapor condenses to a fluid, in the condenser. The fluid is then pumped to the inside of the building, where it enters an evaporator. In this evaporator, small spray nozzles spray the cooling fluid into a chamber, where the pressure drops and the fluid evaporates. Since the evaporation absorbs heat form the surroundings, the surroundings cool off, and thus the evaporator absorbs or adds heat to the system. The vapor is then returned to the compressor.A metering device acts as a restriction in the system at the evaporator to ensure that the heat being absorbed by the system is absorbed at the proper rate. Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... 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. ... Look up condenser in Wiktionary, the free dictionary. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...


Central, 'all-air' air conditioning systems are often installed in modern residences, offices, and public buildings, but are difficult to retrofit (install in a building that was not designed to receive it) because of the bulky air ducts required. A duct system must be carefully maintained to prevent the growth of pathogenic bacteria in the ducts. An alternative to large ducts to carry the needed air to heat or cool an area is the use of remote fan coils or split systems. These systems, although most often seen in residential applications, are gaining popularity in small commercial buildings. The remote coil is connected to a remote condenser unit using piping instead of ducts. A pathogen or infectious agent is a biological agent that causes disease or illness to its host. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ...


Dehumidification in an air conditioning system is provided by the evaporator. Since the evaporator operates at a temperature below dew point, moisture is collected at the evaporator. This moisture is collected at the bottom of the evaporator in a condensate pan and removed by piping it to a central drain or onto the ground outside. A dehumidifier is an air-conditioner-like device that controls the humidity of a room or building. They are often employed in basements which have a higher relative humidity because of their lower temperature (and propensity for damp floors and walls). In food retailing establishments, large open chiller cabinets are highly effective at dehumidifying the internal air. Conversely, a humidifier increases the humidity of a building. Dew on a spider web 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 water vapor to condense into water, called dew. ... A dehumidifier is a household appliance that reduces the level of humidity in the air. ... This does not adequately cite its references or sources. ... A humidifier is a household appliance that increases humidity (moisture) in a single room or in the entire home. ...


Air-conditioned buildings often have sealed windows, because open windows would disrupt the attempts of the HVAC system to maintain constant indoor air conditions.


HVAC energy efficiency and noise

Heating energy

Water heating is more efficient for heating buildings and was the standard many years ago. Today forced air systems can double for air conditioning and are more popular. The most efficient central heating method is geothermal heating. Geothermal heating is a method of heating and cooling a building. ...


Energy efficiency can be improved even more in central heating systems by introducing zoned heating. This allows a more granular application of heat, similar to non-central heating systems. Zones are controlled by multiple thermostats. In water heating systems the thermostats control zone valves, and in forced air systems they control zone dampers inside the vents which selectively block the flow of air. A thermostat is a device for maintaining the temperature of a system within a range by controlling the flow of heat energy into or out of the system. ... A zone valve is a specific type of valve used to control the flow of water or steam in a hydronic heating or cooling system. ... A zone damper is a specific type of damper used to control the flow of air in an HVAC heating or cooling system. ...


Air conditioning energy

The performance of vapor compression refrigeration cycles is limited by thermodynamics. These AC and heat pump devices move heat rather than convert it from one form to another, so thermal efficiencies do not appropriately describe the performance of these devices. The Coefficient-of-Performance (COP) measures performance, but this dimensionless measure has not been adopted, but rather the Energy Efficiency Ratio (EER). To more accurately describe the performance of air conditioning equipment over a typical cooling season a modified version of the EER is used, and is the Seasonal Energy Efficiency Ratio (SEER). The SEER article describes it further, and presents some economic comparisons using this useful performance measure. 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. ... A diagram of a simple heat pumps vapor-compression refrigeration cycle: 1) condenser, 2) expansion valve, 3) evaporator, 4) compressor. ... The thermal efficiency () is a dimensionless performance measure of a thermal device such as an internal combustion engine, a boiler, or a furnace, for example. ... Seer has several possible meanings: A fortune teller or prophet The fictional character on the television series Charmed The Seasonal energy efficiency ratio standard for air conditioning appliances This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...


HVAC Systems Design and Safety

Heating, ventilating and air-conditioning (HVAC) systems can play several roles to reduce the environmental impact of buildings. The primary function of HVAC systems is to provide healthy and comfortable interior conditions for occupants. Well-designed, efficient systems do this with minimal non-renewable energy and air and water pollutant emissions. Cooling equipment that avoids chlorofluorocarbons and hydrochlorofluorocarbons (CFCs and HCFCs) eliminates a major cause of damage to the ozone layer.[citation needed] For other uses, see CFC (disambiguation). ... This article should be merged with Freon, Halon, CFC, and Hydrochlorofluorocarbon and added to Alkyl halide Hydrochlorofluorocarbons (HCFCs) is one of a class of fluorocarbon compounds that are used primarily as chlorofluorocarbon (CFC) substitutes. ... The ozone layer is a layer in Earths atmosphere which contains relatively high concentrations of ozone (O3). ...


However, even the best HVAC equipment and systems cannot compensate for a building design with inherently high cooling and heating needs.[citation needed] The greatest opportunities to conserve non-renewable energy are through architectural design that controls solar gain, while taking advantage of passive heating, daylighting, natural ventilation and cooling opportunities. The critical factors in mechanical systems' energy consumption - and capital cost - are reducing the cooling and heating loads they must handle.


Major terms

  • Air Change per Hour (ACH): Number of fresh air changes per hour particularly for each service.
  • Air handler, or air handling unit (AHU): Central unit consisting of a blower, heating and cooling elements, filter racks or chamber, dampers, humidifier, and other central equipment in direct contact with the airflow. This does not include the ductwork through the building.
  • British thermal unit (BTU): Any of several units of energy (heat) in the HVAC industry, each slightly more than 1 kJ. One BTU is the energy required to raise one pound of water one degree Fahrenheit, but the many different types of BTU are based on different interpretations of this “definition”. The power of HVAC systems (the rate of cooling and dehumidifying or heating) is sometimes expressed in BTU/hour instead of simply watts.
  • Chiller: A device that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. This cooled liquid flows through pipes in a building and passes through coils in air handlers, fan-coil units, or other systems, cooling and usually dehumidifying the air in the building. Chillers are of two types; air-cooled or water-cooled. Air-cooled chillers are usually outside and consist of condenser coils cooled by fan-driven air. Water-cooled chillers are usually inside a building, and heat from these chillers is carried by recirculating water to outdoor cooling towers.
  • Controller: A device that controls the operation of part or all of a system. It may simply turn a device on and off, or it may more subtly modulate burners, compressors, pumps, valves, fans, dampers, and the like. Most controllers are automatic but have user input such as temperature set points, e.g. a thermostat. Controls may be analog, or digital, or pneumatic, or a combination of these.
  • Fan-coil unit (FCU): A small terminal unit that is often composed of only a blower and a heating and/or cooling coil (heat exchanger), as is often used in hotels, condominiums, or apartments.
  • Condenser: A component in the basic refrigeration cycle that ejects or removes heat from the system. The condenser is the hot side of an air conditioner or heat pump. Condensers are heat exchangers, and can transfer heat to air or to an intermediate fluid (such as water or an aqueous solution of ethylene glycol) to carry heat to a distant sink, such as ground (earth sink), a body of water, or air (as with cooling towers).
  • Constant air volume (CAV): Actually means "constant air flow rate" or "constant air volume per time", not "constant air volume". This is applied to all-air or air-water HVAC systems that have variable supply-air temperature but constant flow rate of air. Most residential forced-air systems are small CAV systems with on/off control.
  • Damper: Equipment in duct to control air flow in duct.
  • Evaporator: A component in the basic refrigeration cycle that absorbs or adds heat to the system. Evaporators can be used to absorb heat from air (by reducing temperature and by removing water) or from a liquid. The evaporator is the cold side of an air conditioner or heat pump.
  • Furnace: A component of an HVAC system that adds heat to air or an intermediate fluid by burning fuel (natural gas, oil, propane, butane, or other flammable substances) in a heat exchanger.
  • Fresh air intake (FAI): A vent from outside a building. Outside air can be used to replace air in the building that has been exhausted by the system, or to provide fresh air for combustion of fuel.
  • Grilles: Equipment in duct to control air flow in duct.
  • Heat load, heat loss, or heat gain: Terms for the amount of heating (heat loss) or cooling (heat gain) needed to maintain desired temperatures and humidities in controlled air. Regardless of how well-insulated and sealed a building is, buildings gain heat from warm air or sunlight or lose heat to cold air and by radiation. Engineers use a heat load calculation to determine the HVAC needs of the space being cooled or heated.
  • Louvres: Blades to control air flow amount in ducts.
  • Makeup air unit (MAU): An air handler that conditions 100% outside air. MAUs are typically used in industrial or commercial settings, or in once- through (blower sections that only blow air one-way into the building), low flow (air handling systems that blow air at a low flow rate), or primary-secondary (air handling sytems that have an air handler or rooftop unit connected to an add-on makeup unit or hood) commercial HVAC systems.
  • Roof-top unit (RTU): An air-handling unit, defined as either "recirculating" or "once-through" design, made specifically for outdoor installation. They most often include, internally, their own heating and cooling devices. RTUs are very common in some regions, particularly in single-story commercial buildings.
  • Variable air volume (VAV) system: An all-air or air-water HVAC system that has a stable supply-air temperature, but the flow rate of air varies to meet the thermal load. Compared to CAV systems, these systems waste less energy through unnecessarily-high fan speeds. Most new commercial buildings have VAV systems.
  • Thermal zone: A single or group of neighboring indoor spaces that the HVAC designer expects will have similar thermal loads. Building codes may require zoning to save energy in commercial buildings. Zones are defined in the building to reduce the number of HVAC subsystems, and thus initial cost. For example, for perimeter offices, rather than one zone for each office, all offices facing west can be combined into one zone. Small residences typically have only one conditioned thermal zone, plus unconditioned spaces such as unconditioned garages, attics, and crawlspaces, and unconditioned basements.

An air handling unit; air flow is from the right to left in this case. ... The British thermal unit (BTU or Btu) is a unit of energy used in the Power, Steam Generation and Heating and Air Conditioning industry globally. ... A kilojoule (abbreviation: kJ) is a unit of energy equal to 1000 joules. ... For other uses, see Fahrenheit (disambiguation). ... For other uses, see Watt (disambiguation). ... York International water-cooled chiller. ... 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. ... An analog or analogue signal is any time continuous signal where some time varying feature of the signal is a representation of some other time varying quantity. ... A digital system is one that uses discrete values (often electrical voltages), especially those representable as binary numbers, or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (ie, as in an analog system). ... Pneumatics, from the Greek πνευματικός (pneumatikos, coming from the wind) is the use of pressurized air in science and technology. ... Look up condenser 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. ... Constant Air Volume (CAV) is a type of heating, ventilating, and air-conditioning (HVAC) system. ... In a duct or chimney, a damper is a valve or plate that stops or regulates the flow of air. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... A furnace is a device for heating air or any other fluid. ... A variable air volume (VAV) device is a computer-controlled zone damper used in HVAC systems to vary the flow of air through ductwork. ...

Other HVAC equipment

Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... 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. ... An air handling unit; air flow is from the right to left in this case. ... A boiler is a closed vessel in which water or other fluid is heated under pressure. ... Image 1: Natural draft wet cooling towers at Didcot Power Station, UK Cooling towers are evaporative coolers used for cooling water or other working medium to near the ambient wet-bulb air temperature. ... A zone damper is a specific type of damper used to control the flow of air in an HVAC heating or cooling system. ... A diffuser is the mechanical device that is designed to control the characteristics of a fluid at the entrance to a thermodynamic open system. ... A round duct connecting to a typical diffuser Ducts are used in heating, ventilation, and air conditioning (HVAC) to carry air - these include conditioned, fresh, stale, foul (toilet extract), and contaminated air (flue exhaust, fume extraction) - from place to place. ... It has been suggested that this article or section be merged with Economiser. ... Evaporative coolers (also called air coolers or desert coolers) are cooling devices which uses simple evaporation of water in air. ... Household Electric Fan A mechanical fan is a device used to produce an airflow for the purpose of creature comfort, ventilation, exhaust, or any other gaseous transport. ... 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. ... 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. ... A humidifier is a household appliance that increases humidity (moisture) in a single room or in the entire home. ... A dehumidifier is a household appliance that reduces the level of humidity in the air. ... A HVAC control system is a computerized system for climate control in buildings. ... Piping is used to convey fluids (usually liquids and gases but sometimes loose solids) from one location to another. ... This article is about a mechanical device. ... These water valves are operated by handles. ... Small Variable Frequency Drive (VFD) A Variable Frequency Drive (sometimes abbreviated VFD) is system for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor. ...

HVAC industry and standards

In America

USA

Main article: American Society of Heating, Refrigerating and Air-Conditioning Engineers
(ASHRAE)

The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) is an international voluntary organization for people involved in heating, ventilation, air conditioning, or refrigeration (HVAC&R). ...

In Europe

In the United Kingdom

The Chartered Institute of Building Services Engineers is a body that covers the essential services that allow buildings to operate. It includes the electrotechnical, heating, ventilating, air conditioning, refrigeration and plumbing industries. To train as a building services engineer, the academic requirement is GCSEs (A-C) / Standard Grades (1-3) in Maths and Science, which are important in measurements, planning and theory. Employers will often want a degree in a branch of engineering, such as building environment engineering, electrical engineering or mechanical engineering. The Chartered Institute of Building Services Engineers (CIBSE) represents building services engineers and their various specialities. ... Services are: plural of service Tertiary sector of industry IRC services Web services the name of a first-class cricket team in India This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... HVAC may also stand for High-voltage alternating current HVAC is an initialism that stands for heating, ventilation and air-conditioning. This is sometimes referred to as climate control. ... Ventilation is movement of air, and can be used in the following contexts: ventilation (architecture) ventilation (firefighting) ventilation (physiology) This is a disambiguation page: a list of articles associated with the same title. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... 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. ... A plumber wrench for working on pipes and fittings A complex arrangement of rigid steel piping, stop valves regulate flow to various parts of the building. ... For other uses, see Train (disambiguation). ... Plato is credited with the inception of academia: the body of knowledge, its development and transmission across generations. ... A B.A. issued as a certificate A degree is any of a wide range of status levels conferred by institutions of higher education, such as universities, normally as the result of successfully completing a program of study. ... Engineering is the applied science of acquiring and applying knowledge to design, analysis, and/or construction of works for practical purposes. ...


Within the construction sector, it is the job of the building services engineer to design, install and maintain the essential services such as gas, electricity, water, heating and lighting, as well as many others. These all help to make buildings comfortable and healthy places to live and work in. Building Services is part of a sector that has over 51,000 businesses and employs over 500,000 people. This sector has an annual turnover of £19.3 billion which represents 2%-3% of the GDP. This article does not cite any references or sources. ... All Saints Chapel in the Cathedral Basilica of St. ... Installation can be used to refer to Installation (computer programs) of an operating system or program. ... For other uses, see Electricity (disambiguation). ... Not to be confused with lightning. ... This article does not cite any references or sources. ...


The most recognized standards for HVAC design is based on ASHRAE data. ASHRAE is the American Society of Heating, Refrigerating and Air-Conditioning Engineers. The ASHRAE Handbook's most general volume, of four, is Fundamentals; it includes heating and cooling calculations. Each volume of the ASHRAE Handbook is updated every four years. The design professional must consult ASHRAE data for the standards of design and care as the typical building codes provides little to no information on HVAC design practices; such codes, such as the UMC and IMC, do include much details on installation requirements, however. Other useful reference materials include items from SMACNA, ACCA, and technical trade journals. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) is an international voluntary organization for people involved in heating, ventilation, air conditioning, or refrigeration (HVAC&R). ... The Sheet Metal and Air Conditioning Contractors National Association (SMACNA; pronounced Smack-Nah) is an international association of union HVAC contractors. ... The Association of Chartered Certified Accountants (ACCA) is a British chartered accountancy body with a global presence that offers the Chartered Certified Accountant (Designatory letters ACCA or FCCA) qualification worldwide. ...


See also

It has been suggested that this article or section be merged with Absorptive refrigeration The absorption refrigerator is a refrigerator that utilizes a heat source to provide the energy needed to drive the cooling system rather than being dependent on electricity to run a compressor. ... The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) is an international voluntary organization for people involved in heating, ventilation, air conditioning, or refrigeration (HVAC&R). ... An architectural engineer applies the skills of many engineering disciplines to the design, construction, operation, maintenance, and renovation of buildings while paying attention to their impacts on the surrounding environment. ... An example of baseboards A baseboard or skirting board or skirting is a wooden board, normally three inches to 11 inches (75–300 mm) high, covering the lowest part of an interior wall. ... // Building engineering: a discipline for the modern era Building engineering, commonly known in the US as architectural engineering, is an emerging engineering discipline that concerns with the planning, design, construction, operation, renovation, and maintenance of buildings, as well as with their impacts on the surrounding environment. ... This article does not cite any references or sources. ... Building indoor environment covers the environmental aspects in the design, analysis, and operation of energy-efficient, healthy, and comfortable buildings. ... For the Grand Central Records albums, see Central Heating (Grand Central album) and Central Heating 2. ... The Chartered Institute of Building Services Engineers (CIBSE) represents building services engineers and their various specialities. ... BACnet is a Data Communications Protocol for Building Automation and Control Networks. ... Famous Supply is a family-owned wholesale distributor of HVAC, Plumbing, Industrial/PVF, and Building Products primarily to contractors in the commercial, residential, industrial and institutional markets. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... LonWorks is a networking platform specifically created to address the unique performance, reliability, installation, and maintenance needs of control applications. ... Mechanical Engineering is an engineering discipline that involves the application of principles of physics for analysis, design, manufacturing, and maintenance of mechanical systems. ... 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. ... Solar power describes a number of methods of harnessing energy from the light of the sun. ... Pressurisation ductwork is a fire protection system subject to stringent bounding. ... Smoke Exhaust Ductwork is typically protected via passive fire protection means, subject to fire testing and stringent bounding, and is used to remove smoke from buildings, ships or offshore structures to enable emergency evacuation as well as improved firefighting. ... Underfloor heating is a unique traditional form of central heating gaining newfound popularity. ...

References

  1. ^ Designer's Guide to Ceiling-Based Air Diffusion, Rock and Zhu, ASHRAE, Inc., Atlanta, GA, USA, 2002
  2. ^ Ventilation and Infiltration chapter, Fundamentals volume of the ASHRAE Handbook, ASHRAE, Inc., Atlanta, GA, 2005
  • Modern Refrigeration and Air Conditioning (August 2003) by Althouse, Turnquist, and Bracciano, Goodheart-Wilcox Publisher; 18th edition
  • International Mechanical Code (March 6, 2006) by the International Code Council, Thomson Delmar Learning; 1 edition

The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) is an international voluntary organization for people involved in heating, ventilation, air conditioning, or refrigeration (HVAC&R). ...

External links

Wikibooks
Wikibooks has a book on the topic of
How to reduce home energy usage#Residential ventilation issues
Wikimedia Commons has media related to:
Climate Control
  • HVAC VIET NAM
  • Complete HVAC Visual Training
  • The UK Selfbuild FAQ
  • The effects of displacement ventilation
  • Natural Ventilation - by Andy Walker of the National Renewable Energy Laboratory
  • IEA Energy Conservation in Buildings and Community Systems Programme.
  • BTU Calculator A worksheet by the Association of Home Appliance Manufacturers to help you estimate how much cooling capacity you need.
  • HVAC Formulas - Common HVAC industry formula resource
  • ASHRAE - The American Society of Heating, Refrigerating and Air-Conditioning Engineers
  • High Performance HVAC - Comprehensive articles about HVAC, HVAC applications, and saving energy with HVAC systems

  Results from FactBites:
 
HVAC - Wikipedia, the free encyclopedia (4282 words)
HVAC (pronounced either "H-V-A-C" or, occasionally, "H-VAK") is an initialism/acronym that stands for "heating, ventilation and air-conditioning".
These three functions are closely interrelated, as they control the temperature and humidity of the air within a building in addition to providing for smoke control, maintaining pressure relationships between spaces, and providing fresh air for occupants.
Thermostats control the operation of HVAC systems, turning on the heating or cooling systems to bring the building to the set temperature.
Category:HVAC - Wikipedia, the free encyclopedia (83 words)
HVAC stands for "Heating, Ventilation and Air Conditioning"
The main article for this category is HVAC.
There are 3 subcategories shown below (more may be shown on subsequent pages).
  More results at FactBites »

 
 

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