Lecture Objectives Finish thermal comfort Velocity Temperature Concentration Discuss different issues about CFD AIRPAK
Thermal comfort Temperature and relative humidity
Thermal comfort Velocity Can create draft Draft is related to air temperature, air velocity, and turbulence intensity.
Thermal comfort Mean radiant temperature potential problems Asymmetry Warm ceiling (----) Cool wall (---) Cool ceiling (--) Warm wall (-)
Prediction of thermal comfort Predicted Mean Vote (PMV) + 3 hot + 2 warm + 1 slightly warm PMV = 0 neutral -1 slightly cool -2 cool -3 cold PMV = [0.303 exp ( -0.036 M ) + 0.028 ] L L - Thermal load on the body L = Internal heat production – heat loss to the actual environment L = M - W - [( Csk + Rsk + Esk ) + ( Cres + Eres )] Predicted Percentage Dissatisfied (PPD) PPD = 100 - 95 exp [ - (0.03353 PMV4 + 0.2179 PMV2)] Empirical correlations Ole Fanger Further Details: ANSI/ASHRAE standard 55, ISO standard 7730
CFD AIRPAK
Issues to discus Boundary conditions Mesh Convergence (monitoring points) Grid sensitivity analysis Result presentations ……