Detailed multi-node model of human physiology to predict dynamic thermal comfort responses Dusan FIALA, PhD University of Stuttgart Germany dfiala@ibbte.uni-stuttgart.de
Contents Model Systems Validation examples Physiological modelling of thermal comfort
Model of human thermoregulation: Passive System
Model of human thermoregulation: Active System
- Active System: System coefficients.5 5 - - [g min K ] b sw,sk - coefficient..5..5. - -8-6 -4-4 T sk,m,t [K] Regression bsw,sk coefficient b - sh,sk [W K ] -5 - -5 - -5-4 - - -8-6 -4 - T sk,m,t [K] Regression b sh,sk coefficient bdl,sk [W K ²] 4 3 - -8-6 -4-4 T sk,m,t [K] Regression b dl,sk coefficient bdl,hy [W K ²] 8 7 6 5 4 3 - coefficient bcs,sk [K ] - -4-6 -8 - - [g min K ] b sw,hy coefficient 4 8 6 4 -.5.5.5 T hy,t [K] Regression b dl,hy - - -8-6 -4 - T sk,m,t [K] Regression b cs,sk - -.5.5.5 T hy,t [K] Regression b sw,hy
evap. heat loss [W] Transient conditions mean skin temp. [ C] 37 35 33 3 5 5 5 8 C Ta=Tw=48 C 8 C 3 6 9 5 8 4 time [min] 37 rectal temperature [ C] rectal temp. [ C] evaporation [W] 37.5 37..5 5 5 Ta=43 C Ta=7 C Ta=43 C 3 3 8 5 mean skin temp. [ C] metabolism [W] experiment simulation Ta=Tw, va<.m/s, rh=3%, Icl=.clo, act=met, n=3 3 6 9 5 8 4 time [min] experiment simulation Stolwijk model Ta=Tw, va=.m/s, rh=3%, Icl=.clo, act=met, n=3
Validation: Principal human thermal behaviour metabolism [W] mean skin temp. [ C] 3 3 8 6 4 3 37 rectal tem mp. [ C] evaporation [W/m²] mean skin temp. [ C] 3 3 8 4 8 6 4 37 rectal T [ C] 5 5 7 ambient temperature [ C] experiment: mean ± SD simulation t=6min, Tw=Ta, va=.3m/s, rh=5%, act=.8met, Icl=.clo, n=44 4 8 3 4 44 48 ambient temperature [ C] experiment : mean ± SD simulation t=6min, Tw=Ta, va=.m/s, rh=3%, Icl=.clo, act=met, n=3
Radiant Temperature Asymmetry 4 Temperature e [ C] 35 3 5 Neck Pos Forehead Foot instep Leg LowPost Mean Skin Temp Rectal Temp Mean Rad Temp Air Temp Sim. 5 5 5 Radiant temperature asymmetry [K]
Field measurements Hiking : Boundary conditions Air temperature Wind speed..4. air temperature [ C] 8. 6. 4.. Simulation air speed [m/s]...8..6 3 6 9 5 8 3 6 9 5 8 Solar Radiation Activity / Metabolic rate 9 7 Solar Radiation [W/m] 8 7 6 5 4 3 Qmet [W] 6 5 4 3 Simulation 3 6 9 5 8 3 6 9 5 8
Field measurements Hiking : Body temperatures 4 Mean skin temperature 4 Body core temperature 39 Tskm [ o C] 3 3 Sim. Sim. 3 Trectal [ o C] 37 Sim. Sim. 3 8 6 35 3 6 9 5 8 3 6 9 5 8 Skin temperature: Chest Skin temperature: Back 4 4 Tsk, chest [ o C] 3 3 Tsk, back [ o C] 3 Sim. Sim. 3 8 3 6 8 3 6 9 5 8 3 6 9 5 8
Field measurements Hiking : Skin temperatures Tsk, arm [ o C] 4 3 3 8 6 4 Skin temperature: Upper arm 3 6 9 5 8 Sim. Sim. 3 Tsk, forearm [ o C] 4 3 3 8 6 4 Skin temperature: Lower arm 3 6 9 5 8 Sim. Sim. 3 Tsk, leg [ o C] 4 3 3 8 6 4 Skin temperature: Upper Leg 3 6 9 5 8 Sim. Sim. 3 Tsk, calf [ o C] 4 3 3 8 6 4 Skin temperature: Lower leg 3 6 9 5 8 Sim. Sim. 3
Field measurements Hiking (Test VI). Air temperature 35 Solar Radiation air temperature [ C]. 8. 6. 4... -. 3 6 9 5 8 Solar Radiation [W/m] 3 5 5 5 3 6 9 5 8 Skin temperature: Chest Mean skin temperature 4 4 Tsk, chest [ o C] 3 3 Sim. Sim. 3 Tskm [ o C] 3 3 Sim. Sim. 3 8 8 6 3 6 9 5 8 6 3 6 9 5 8
Thermal Comfort: modelling approaches Existing models Nevins et al.: Fanger Model (iso773): TS = f (T o,rh) TS = f ( Q), i.e.heat flux Gagge Model: TS = f (T a,p a ) f (wsk) Nishi et al Model: TS = f (Tsk) Aser & Hsu Model: Question: TS = f (KS) } What physiological parameters do actually govern the human Thermal Sensation? Physilogical approach
Simulation and analysis of TC experiments Thermal Sensation 3 - - -3 TSV = f (Sw) TSV = f (Qsk) 3 - - -3 Thermal Sensation - - 3 4 5 6 msw [g/min] - 4 6 8 Qsk - Qsk, [W] Thermal Sensation 3 - - -3 TSV = f (Thy) TS = f (Tsk) 3 - - -3 Thermal Sensation -.6 -.4 -...4-5 -4-3 - - 3 Thy - Thy, [K] Tsk,m - Tsk,m, [K]
Effect of body core temperature (exercising subjects) φ = gsk x ghy 6.5 5 4. [ ] [ ] gsk 3 ghy.5. - -8-6 -4 - -.5..5..5. Tsk,m - Tsk,m, [K] Thy - Thy, [K]
Dynamic components of Thermal Sensation Therma al Sensation - - Dynamic Thermal Senstation (DTS) Ta=8 C Ta=8 C Ta=8 C (8.4 F) (64.4 F) (8.4 F) f + ( ) dt sk,m f ( ) dt - dt sk,m dt -3 3 6 9 5 8 4 time [min] experiment static TS dynamic TS (DTS)
Validation examples: Ramps Therm mal Sensation [ ] 3 - - -3 3 3 9 8 7 6 5 3 6 9 5 8 4 Air tem mperature Ta [ C] time [min] experiment DTS (Ta) Tw=Ta va=.m/s Tdew= C Icl=.5clo act=.met n=
Validation examples: Step changes in Ta Therm mal Sensation [ ] 3 - - -3 3 6 9 5 8 time [min] exp.: To = 7/ C (sw/n) exp.: To = /7 C (N/s C) DTS: To = 7/ C DTS: To = /7 C
Validation examples: Transient exercise Therma al Sensation 3 - - 3 level [met] activity experiment simulation (activity) -3 5 3 45 6 75 9 5 time [min] Ta =Tw = C va =.m/s rh = 5% Icl=.clo n =
Validation examples: Periodic changes Therm mal Sensation [ ] 3 - - -3 5 3 45 6 75 9 5 time [min] exp.: males exp.: female DTS (Ta) 3 8 6 4 Air tem mperature Ta [ C] Tw=Ta va=.5m/s rh=5% Icl=.7clo n=
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