Heating, ventilation, and air conditioning
"Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers).[3][4][5] Basing HVAC on a larger network helps provide an economy of scale that is often not possible for individual buildings, for utilizing renewable energy sources such as solar heat,[6][7][8] winter's cold,[9][10] the cooling potential in some places of lakes or seawater for free cooling, and the enabling function of seasonal thermal energy storage.HVAC is based on inventions and discoveries made by Nikolay Lvov, Michael Faraday, Rolla C. Carpenter, Willis Carrier, Edwin Ruud, Reuben Trane, James Joule, William Rankine, Sadi Carnot, Alice Parker and many others.[11] Multiple inventions within this time frame preceded the beginnings of the first comfort air conditioning system, which was designed in 1902 by Alfred Wolff (Cooper, 2003) for the New York Stock Exchange, while Willis Carrier equipped the Sacketts-Wilhems Printing Company with the process AC unit the same year.Incomplete combustion occurs when there is insufficient oxygen; the inputs are fuels containing various contaminants and the outputs are harmful byproducts, most dangerously carbon monoxide, which is a tasteless and odorless gas with serious adverse health effects.[17] Ventilation is the process of changing or replacing air in any space to control the temperature or remove any combination of moisture, odors, smoke, heat, dust, airborne bacteria, or carbon dioxide, and to replenish oxygen.It plays a critical role in maintaining a healthy indoor environment by preventing the buildup of harmful pollutants and ensuring the circulation of fresh air.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.By strategically placing openings, such as windows or vents, on opposing walls, air is channeled through the space to enhance cooling and ventilation.[23] Natural ventilation [24] is a key factor in reducing the spread of airborne illnesses such as tuberculosis, the common cold, influenza, meningitis or COVID-19.Opening doors and windows are good ways to maximize natural ventilation, which would make the risk of airborne contagion much lower than with costly and maintenance-requiring mechanical systems.In settings where respiratory isolation is difficult and climate permits, windows and doors should be opened to reduce the risk of airborne contagion.[30] UVC or Ultraviolet Germicidal Irradiation is a function used in modern air conditioners which reduces airborne viruses, bacteria, and fungi, through the use of a built-in LED UV light that emits a gentle glow across the evaporator.As the cross-flow fan circulates the room air, any viruses are guided through the sterilization module’s irradiation range, rendering them instantly inactive.Free cooling systems can have very high efficiencies, and are sometimes combined with seasonal thermal energy storage so that the cold of winter can be used for summer air conditioning.Common storage mediums are deep aquifers or a natural underground rock mass accessed via a cluster of small-diameter, heat-exchanger-equipped boreholes.Outside of North America, packaged systems are only used in limited applications involving large indoor space such as stadiums, theatres or exhibition halls.In food retailing establishments, large open chiller cabinets are highly effective at dehumidifying the internal air.Additionally, very dirty or plugged filters can cause overheating during a heating cycle, which can result in damage to the system or even fire.Utilizing this large source of relatively moderate temperature earth, a heating or cooling system's capacity can often be significantly reduced.Traditional air conditioners run using alternating current, and hence, any direct-current solar power needs to be inverted to be compatible with these units.For example, the fan blades used to move the air are usually stamped from sheet metal, an economical method of manufacture, but as a result they are not aerodynamically efficient.The HVAC industry was historically regulated by the manufacturers of HVAC equipment, but regulating and standards organizations such as HARDI (Heating, Air-conditioning and Refrigeration Distributors International), ASHRAE, SMACNA, ACCA (Air Conditioning Contractors of America), Uniform Mechanical Code, International Mechanical Code, and AMCA have been established to support the industry and encourage high standards and achievement.However, before taking up the heat load calculation, it is necessary to find fresh air requirements for each area in detail, as pressurization is an important consideration.[45] The building environmental design standard aims to:[45] In the United States, federal licensure is generally handled by EPA certified (for installation and service of HVAC devices).ASHRAE regularly organizes two annual technical committees and publishes recognized standards for HVAC design, which are updated every four years.[56] Another popular society is AHRI, which provides regular information on new refrigeration technology, and publishes relevant standards and codes.To train as a building services engineer, the academic requirements are GCSEs (A-C) / Standard Grades (1-3) in Maths and Science, which are important in measurements, planning and theory.[citation needed] CIBSE publishes several guides to HVAC design relevant to the UK market, and also the Republic of Ireland, Australia, New Zealand and Hong Kong.The Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE) was established to promote the HVAC industry in India.
Ventilation ductdiffuserdamperthermostatfiltersinterlockcapacitortemperaturehumiditythermal comfortindoor air qualitymechanical engineeringthermodynamicsfluid mechanicsheat transferRefrigerationcircuit breakersskyscrapershealthy buildingventilationnaturalroom air distributionHVAC control systemcontrol systemsbuilding servicesNORAD'sdistrict heatingdistrict coolingrenewable energylakes or seawaterfree coolingseasonal thermal energy storageNikolay LvovMichael FaradayRolla C. CarpenterWillis CarrierEdwin RuudReuben TraneJames JouleWilliam RankineSadi CarnotAlice ParkerIndustrial RevolutionHeater (disambiguation)Central heatingboilerfurnaceheat pumpfurnace roommechanical roomconvectionradiationSpace heaterselectricityNichromeportable heatersradiatorshydronicsUnderfloor air distributioncarbon monoxidenitrogen oxidesformaldehydevolatile organic compoundsVentilation (architecture)Duct (flow)ventilation systemspollutionfiltrationair handlerDirect driveceiling fansPassive ventilationdowndraught'plenum' principletrickle ventsASHRAEbuilding envelopepenetrationscross ventilationstack effectAir conditioningair changes per hourwind tunnelUltraviolet Germicidal Irradiationvirusesbacteriaconductionrefrigerantsrefrigeration cycleHeat pump and refrigeration cyclecondensing coilexpansion valveevaporating coilcompressorreversing valveheat sinkenthalpysplit systemsdew pointdehumidifierrelative humidityHumidifierenergy efficiencyforced airzone valveszone dampersForecastingGeothermal heat pumpDeath ValleySolar air conditioningEnergy recoveryheat recovery ventilationenergy recovery ventilationheat exchangersenthalpy wheelssensiblelatent heatthermal efficienciesCoefficient of performanceDemand controlled ventilationaffinity lawsAir filterAir handling unitSMACNAUniform Mechanical CodeInternational Mechanical Code