this is about ventilation

... Assignment 2 Calculate the PMV for a group of persons in a room with temperature and relative humidity at 24 C and 60%. The pressure is 1 atm. The wall temperature is 27 C. The air velocity is 0.2 m/s. The persons are seated in office reading with 1.0 clo. The Stefan-Boltzmann constant is 5.67 *10-8 W/mK4. The emittance for the cloth is 0.8, and the emittance for the walls is 0.7. CO2 tracer gas decay method is employed to measure the ventilation rate in a naturally ventilated room. The outdoor CO2 level is a constant at 506.7 ppm. The indoor outdoor CO2 level as a function of time is listed below. The volume of the room is 180 m. The air density is 1.225 kg/m (1) Derive the indoor outdoor CO2 level as a function of time, outdoor CO2 level, ventilation rate, air density, and room volume based on mass balance. (2) Calculate the ventilation rate in m3/h. Indoor CO2 (ppm) 990 994 989 Time (h) 0.00 0.02 0.03 0.05 0.07 0.08 0.10 0.12 0.13 0.15 0.17 0.18 0.20 0.22 0.23 0.25 0.27 0.28 0.30 0.32 0.33 0.35 986 981 975 971 958 952 950 936 938 933 932 931 918 909 903 904 901 897 875 876 0.37 0.38 0.40 0.42 0.43 0.45 0.47 0.48 0.50 872 872 870 868 862 864 858 859 di Cort-Gult)) m = - Lort Widely used measurement method CO2 mass balance Cont () Pa ear (Cart - Cists) / - m Cat - City v. dcint) m dt d Chart - Cin(t)) Cont - Cinct) dy in .dt Solve the equation Par t V Cin(t) = [ (in (0) - Cout) e ] t Cont - dx dX Example: 1600 1400 o Measurement -Exponential regression y = a expex + b 1200 Cin(t)=1131.exp(-0.0041 t)+300 CCO,,out = 300 ppm 1000 800 CO2 Concentration (ppm) 600 im la v 0 Cin(t) = 0,004) 5) 400 200