125 TIE Theory of Indoor Environment THERMAL COMFORT

Transcription

1 ČVUT v Praze Fakula savební Kaedra echnických zařízení budov 125 TIE Theory of Indoor Environmen THERMAL COMFORT Zuzana Veverková

2 THERMAL COMFORT OVERALL COMFORT 8

3 Measuremens of facors for evaluaion of hermal comfor Air emperaure a [ C] Thermomeers, emperaure sensors,... Wihou he influence of radiaion Proeced from radian hea source Necessaryo esablishoperaiveemperaure o Vericalemperauregradien beweenheadand ankles Humidiy Relaive humidiy hygromeer Dry bulb and we bulb emperaure psychromeers Dew poin ofdry air -Dew poin emperaure sensors

4 Measuremens of facors for evaluaion of hermal comfor Dry bulb emperaure Fan We bulb emperaure Evaporaion of waer from he sock lowers he emperaure Air We sock hewebulb ermomeer usually shows a lower emperaure hanhaof hedry bulb ermomeer 10

5 Measuremens of facors for evaluaion of hermal comfor Resulan Temperaure g [ C] - globe emperaure is measured wih a globe hermomeer i includes he effec of air velociy and radian hea source. Measuring heigh = head heigh measuring range from -50 o C copper sphere 150 mm in diameer wih a cenrally placed P100-sensor Temperaure a [ C] and humidiy RH [%] Combined sensor emperaure-humidiy range: -Temperaure -20 o + 60 C - Humidiy 5 o 98% RH

6 Measuremens of facors for evaluaion of hermal comfor Surface emperaure p [ C] Conac sensors -direc hea ransfer beween he surface and he sensor no suiable for maerials wih low hermal conduciviy Uneven surfaces! INFRASENSOR-conacless emperaure measuremen, he influence of surface emissiviy maerial Influence on he mean radian emperaure r and operaive emperaure o.

7 Measuremens of facors for evaluaion of hermal comfor Air velociy v a [m/s] Thermoanemomeric omnidirecional probe (range 0.01 o 1 m/s) Vaneanemomeer sensor (range 0.4 o 20 m / s) Human percepion of air velociy: 0 m/s unpleasan, suffy air 0,1-0,3 m/s mosly pleasan bu dependen on emperaure and clohing Above 0,3 m/s according o emperaure hp:// 14

8 Measuremens of facors for evaluaion of hermal comfor Wha /Why?.Where?.. How long?... Highs: HighofheHeadofsiingperson (1,1 m), ev. sandingperson(1,7 m) ankles(0,1 m) Places/poins

9 Measuremens of facors for evaluaion of hermal comfor Daa logger for recording he measured values Seing a ime sep of soring daa Recording o inernal or exernal memory

10 Thermal comfor assessmen Operaive Temperaure 0 [ C] is defined as a uniform emperaure of a radianly black enclosure in which an occupan would exchange he same amoun of hea by RADIATION plus CONVECTIONas in he acual nonuniformenvironmen. Ican be defined as he average of he meanradian andambien air emperaures, weighed by heir respecive hea ransfer coefficiens. Calculaed value o = a + 2 r Validforlowair velociy(up o 0,2 m/s) and smalldifferenciesbeween a and r (up o 4 C), g o = h c h a c + + h h r r op = operaive emperaure a = air emperaure r = mean radian emperaure (MRT) h c = convecive hea ransfer coefficien h r = mean radiaive hea ransfer coefficien r

11 Mean Radian Temperaure MRT (also effecive emperaure of he surrounding surfaces, medium emperaure of radiaion) is defined as he uniform emperaure of an imaginary enclosure in which he radian hea ransfer from he human body is equal o he radian hea ransfer in he acual non-uniform enclosure = ϕ ϕ 4.T T 4 r r1 1 rn n 273 where r = mean radian emperaure Ti = emperaure of he surrounding surface i, i=1,2,...,n φ rn = shape facor which indicaes he fracion of oal radian energy leaving he clohing surface 0 and arriving direcly on surface i, i=1,2,...n ϕ 12 18

12 Mean Radian Temperaure r = TA T A T N A N / ( A where r = mean radian emperaure [ C] T i = emperaure of he surrounding surface i, i=1,2,...,n A i = surface area of he surrounding surface i, i=1,2,...,n [m 2 ] 1 + A A N ) OperaiveTemperaure o = + a r 2 differenciesbeween a and r (up o 4 C) o r r r operaiveemperaure [ C] air emperaure [ C] meanradian emperaure [ C] resulan -globe emperaure [ C] 19 0 g Valid for low air velociy (up o 0,2 m/s) and small

13 SUMMER WINTER I cl Facors of Human - Clohing Daily common clohing 0,3 panies, T-shir, ligh socks, sandals 0,45 briefs, panies, sockings, ligh dresses wih sleeves, sandals 0,5 pans, shirs wih shor sleeves, ligh rousers, ligh socks, shoes 0,6 pans, shirs, ligh pans, socks, shoes 0,7 underwear, shirs, pans, socks, shoes (panies, peicoa, sockings, dresses, shoes) Uni 1 clo=0,155m 2.K/W clo < 0,5 EN ISO ,6-1,2 >3,5 (c) prof. K. Kabele 20 a kol. 2016

14 THERMAL COMFORT PMV - Prediced Mean Voe mean hermal feeling of a person PPD - Prediced Percenage of Dissaisfied Inpu parameers Relaive humidiy Air emperaure PMV PPD Air velociy Mean radian emperaure Meabolic hea Clohing insulaion (c) prof. K. Kabele a kol

15 PPD Thermal comfor- ČSN EN ISO 7730 C B A - 0,7-0,5-0,2 0,2 0,5 0,7 PMV A/B/C -Caegories of hermal environmen (EN ISO 7730) PMV (Prediced Mean Voe) mean hermal feeling of a person PPD (Prediced Percenage of Dissaisfied) (c) prof. K. Kabele a kol