Air movement and thermal comfort - eScholarship

and Airmovement thermalcomfort on information ThenewASHRAE Standard provides comfort indoor air velocities occupant appropriate for By Marc E. Fountain and Mward A. Arens, Ph.D. MemberASHRAE Associate MemberASHRAE heat of Many, notmost, if commercial trolsthe release metabolic by design innovations, buildings. ecent HVAC primarily by skin the of builtsince middle this regulating temperaturg concerns buildings conservation energy and at skin supply sweadng to use systems varying blood dataon century air distribution and newlaboratory heated and/or cooled to occu- theskinsurface. air have brought substantial deliver drafrs heat at Convective transfer ihe skin lEvels to of attention theissue acceptable ol piedspaces. with surface and temperature local Accordingly', ASHRAEand other varies in air movement officeenvironments. Exten- across skinsurface the have and air motion sunduds desirable organizations produced mayprovide Air movement have shor.r'n that studies for this but also guidelines distributing air.Included sivelaboratory conditions, it may cooling u,alm in vote such documents specifics as: thermalsensation (an important are cool in these the increase riskof unacceptably thermal comfort) is percentage method measuring for of of may Detectable movement be volume airperunittime, air drafts. in related skintemperature cool to of perceived the occupants provid- outdoor andtype location duct closely ail and as by conditions. warmand In andcomfonable to ing freshness pleasantness the outlets. and warm-humid moisture the on conditions, In general, design recommendations as be air, breathing ya it mayalso perceived effect thermal on sensa- cfm have favored specifying deiivered per skinhasa strong annoying. after mechan- than tion,particularly sweating foot space a air has Clearlll specific speed many square of occupied rather triggered. have been airvelocity achieving for thermal isms possible physiological subjective con- specifying and Howwer, desired the end-product froma pleasant comfon. These sequences. range is to sense of sense coolness anunpleasant of oi HVACsystems not cfmper square About theauthon interior air move- or dnft, depending theair emperaturg foot,a cooledbuilding on and it health humidit v, cloth- mentperse; is thecomfort, radiant ternpeftlturg mean at MarcE. Founsinisa PhDcandidate the of (UCB). occupants. ing, metabolic and air movement satisfaction building rate Uniwnity of Califomia-Berkelry preference theoccupant. from Beyond special such laborato cases as his Hereteived BA in physics UCB. of member Fountain a corrsponding is of rooms, in ASH- riesandclean efforts HVACare the Since turnof thecentury, and ASHRAE 1.1(Ph.vsiology Human TC directed producing at thermal have primarily comfon rerarchers RAEandthermal active ther- and been in and that acceptable Environment) has worked define to levels air movement comfort airquality are of since induding malcomfon research 1986 possible for breathing. focus this isthe The anicle of thatareaccepuble thewidest to t s c o n t r i b u t i o n o e S H R A ER e s e a r c h (created group indiriduals b1' within evolving influence theairmovement of oi an Projects RP{62andRP-702 system) thermal on comfort. and architectural serting, to incorporate an HVAC in A. Edu'ard Arensis a professor the Air velocity oneof sixmainvaria- is these results anindoor into elvironmental at Depanment fuchitecture theUniver- of The bles affeaing human thermal comfort. standard. and physical variables sityof California-Berkeley direoor three Thisanicleoutlines current the state otherfiveinclude Design of the Centerfor Environmental mean temperature to (airtemperature radiant Referenceis made also of thisdiscussion. his Raearch. received PhDin archi- He humidity) tr+o and behavionlly investigating effectof air andrelatirre the research fromthe University tectural science of (metabolic and variables rate and movement thermal on comfort the regulated Edinburgh hisundergraduate and and insulation). dwelopment air velocity of limitsin the clothing manen from degrees lhleUniversiry sys- In humans, thermoregulatory the comfort latesr ASHRAE thermal standard. Sundards is serving the SPC-i5-92R on temisresponsible maintaining heu the for hoia Committee, isa conespmding and Whyisair velocity important? a of balance thebodyusing core ol setpoint member TC2.1anda past+hairman of of (37 C) withintheconstrainu the of to design TC 25 (Air FlowAroundBuildines). HVACengineers systems 98.6 F given This con- move and air energy ventilating through sixvariables above system H 1 . 1 R I E J o u n a l A u g u s rI 9 9 3