Operative temperature: Difference between revisions

▲'''Operative temperature''' (<math>t_o</math>), also known as ''Dry resultant temperature'', or ''Resultant temperature'', is defined as a uniform temperature of a imaginary black enclosure in which an occupant would exchange the same amount of heat by [[radiation]] plus [[convection]] as in the actual nonuniform environment.<ref name="7726_1998">{{Cite journal | author = International Standard Organization | year = 1998 | title = ISO 7726:1998 Ergonomics of the thermal environment -- Instruments for measuring physical quantities}}</ref><ref name="7730_2005">{{Cite journal | author = International Standard Organization | year = 2005 | title = ISO 7730:2005 Ergonomics of the thermal environment -- Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria}}</ref><ref name="55_2013">{{Cite journal | author = ASHRAE Standard 55 | year = 2013 | title = Thermal Environmental Conditions for Human Occupancy }}</ref><ref>ASHRAE Terminology, ASHRAE Handbook CD, 1999-2002</ref> Some references also use the terms 'equivalent temperature" or 'effective temperature' to describe combined effects of convective and radiant heat transfer.<ref>Nilsson, H.O., Comfort Climate Evaluation with Thermal Manikin Methods and Computer Simulation Models, National Institute for Working Life, 2004, pg. 37</ref> In design, operative temperature can be defined as the average of the [[Mean radiant temperature|mean radiant]] and [[Dry-bulb temperature|ambient air temperatures]], weighted by their respective [[heat transfer coefficient]]s.<ref>Thermal Comfort, ASHRAE Handbook, Fundamentals, Ch. 9, pg.3, 2009</ref> The instrument used for assessing environmental thermal comfort in terms of operative temperature is called a eupatheoscope and was invented by A. F. Dufton in 1929.<ref>Glossary of Meteorology, American Meteorological Society, < http://amsglossary.allenpress.com/glossary/browse?s=e&p=42>, accessed Sept 2010</ref> Mathematically, operative temperature can be shown as;