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| Heating, ventilation, and air conditioning | |
|---|---|
| Name | Heating, ventilation, and air conditioning |
| Caption | Commercial air handling unit and rooftop units |
| Invented | Ancient Rome to 20th century |
| Inventor | Vitruvius; Willis Carrier |
| Industry | Building services |
| Type | Building technology |
Heating, ventilation, and air conditioning
Heating, ventilation, and air conditioning is the integrated technology for controlling indoor thermal comfort and air quality in buildings and vehicles. It encompasses equipment, distribution networks, controls, and standards developed across eras from antiquity to contemporary engineering. Systems are applied in residential, commercial, industrial, and transportation contexts guided by regulatory frameworks and professional bodies.
Origins trace to Roman hypocaust systems described by Vitruvius and engineering in Ancient Rome, later evolving through innovations in Ottoman Empire bathhouse ventilation and European hearthcraft. The 19th century saw advances tied to industrial figures such as James Watt, George Stephenson, and inventors linked to steam heating in Manchester and Liverpool. Modern air conditioning emerged with inventors and corporations including Willis Carrier, Thomas Midgley Jr., Frederick W. Hyde, and firms like Westinghouse Electric Corporation, American Society of Heating, Refrigerating and Air-Conditioning Engineers, and General Electric. Breakthroughs in refrigeration involved chemists and companies such as Carl von Linde, Frigidaire, DuPont, and researchers associated with RCA and Bell Labs. Twentieth-century adoption was accelerated by infrastructure projects and policies involving New Deal, Federal Reserve-era construction, and postwar suburban growth in United States and United Kingdom metropolitan regions. Environmental and safety concerns prompted regulation tied to international agreements like the Montreal Protocol and standards from organizations such as International Organization for Standardization and national codes influenced by National Fire Protection Association.
Systems comprise heat sources and sinks produced by manufacturers like Carrier Global Corporation, Daikin Industries, Trane Technologies, Mitsubishi Electric, and Johnson Controls. Principal components include heat exchangers, compressors, condensers, evaporators, fans, pumps, ducts, filters, and controls developed by suppliers such as Honeywell International Inc., Schneider Electric, and Siemens. Common system types span forced-air furnaces, boilers, chilled water plants, heat pumps, split systems, packaged units, variable refrigerant flow systems, and centrifugal chillers used in projects by firms like Skanska, Turner Construction Company, and Skidmore, Owings & Merrill. Distribution includes ductwork, radiant floors, and hydronic piping produced to standards from American Society of Mechanical Engineers and installed in buildings by companies like Kiewit, Fluor Corporation, and Balfour Beatty. Control strategies use programmable logic controllers and building management systems from Siemens, Schneider Electric, and Honeywell integrated with sensors and actuators from vendors including Siemens Healthcare and ABB.
Thermodynamic and fluid mechanics principles underpin operation: heat transfer, conduction, convection, and phase-change processes described in texts by Lord Kelvin and Sadi Carnot inform vapor-compression cycles pioneered by Carl von Linde and work on refrigeration by James Harrison. Air movement follows principles studied by Ludwig Prandtl and Osborne Reynolds, while psychrometrics and indoor air quality metrics connect to research from Royal Society and institutions such as Massachusetts Institute of Technology and Imperial College London. Heat sources include combustion in furnaces linked historically to innovators like Abraham Darby and electrical resistance heating developed with contributions from Thomas Edison. Controls apply feedback theory formalized by Norbert Wiener and implemented in modern algorithms used in plants run by Exelon or HVAC research at National Renewable Energy Laboratory.
Design relies on load calculations, thermal modeling, and simulation tools developed by software firms and academic groups at Carnegie Mellon University, Stanford University, and Lawrence Berkeley National Laboratory. Standards and codes include those from ASHRAE, ISO, European Committee for Standardization, and national authorities such as Building Research Establishment and United States Department of Energy. Installers follow practices certified by trade organizations like Air Conditioning Contractors of America and training programs at institutions such as City & Guilds and Apprenticeship programs in Germany (Handwerkskammer). Projects coordinate with architects and engineers from firms like Foster + Partners, Gensler, and AECOM to integrate systems with structural, electrical, and plumbing works overseen in permits from municipal bodies such as New York City Department of Buildings.
Efficiency improvements are driven by refrigerant transitions after the Montreal Protocol and technology advances from companies like Daikin and Carrier. Metrics and incentive programs by ENERGY STAR, European Commission, and utilities such as Pacific Gas and Electric Company shape adoption of high-efficiency equipment and heat-recovery ventilation systems deployed in projects by Siemens and Schneider Electric. Environmental concerns connect to greenhouse gas inventories managed under frameworks like the United Nations Framework Convention on Climate Change and mitigation strategies promoted by World Green Building Council and certification systems such as LEED and BREEAM. Alternative technologies include geothermal heat pumps used in developments by Iceland Geothermal and district heating networks in cities such as Copenhagen and Reykjavík.
Routine maintenance practices derive from manuals and guidelines by manufacturers and institutions including ASHRAE, National Institute for Occupational Safety and Health, and trade associations such as Plumbing-Heating-Cooling Contractors Association. Diagnostic methods employ tools from instrumentation makers like Fluke Corporation, Testo, and Honeywell alongside procedures used in facilities managed by organizations such as University of California campuses or healthcare systems like Mayo Clinic. Fault detection leverages modern predictive maintenance and IoT analytics developed by firms like Siemens, IBM (Watson), and Microsoft for building management, while training and certification are provided by entities such as NATE (North American Technician Excellence).
Applications span residential housing stock managed under policies from Department of Housing and Urban Development, commercial towers designed by studios including Skidmore, Owings & Merrill, industrial process cooling in plants run by BASF and General Motors, and transport HVAC in fleets of Boeing, Airbus, Amtrak, and New York City Transit Authority. Standards and compliance frameworks include codes from International Code Council, safety rules from Occupational Safety and Health Administration, and performance standards from ASHRAE Standard 90.1 and ISO 5149. Academic research and professional development are supported by conferences and journals associated with ASHRAE, CIBSE, and universities such as University of Cambridge and Princeton University.
Category:Building services