n an air-conditioning unit 3.5 m3/s of air at 32 C dry-bulb temperature, 50 percent relative humidity, and standard atmospheric pressure enters the unit. The leaving condition of the air is 18 C dry-bulb temperature and 90 percent relative humdity. Using properties from the psychrometric chart, (a) calculate the refrigerating capacity in kilowatts and (b) determine the rate of water removal from the air

Air enters a cooling coil at the rate of 5000 cfm (2.4 m3/s) at 80 F (27 C). db, 68 F (20 C) wb and sea-level pressure. The air leaves the coil at 55 F (13 C) db, 54 F (12 C) wb. (a) Determine the SHF and the apparatus dew point. (b) Compute the total and sensible heat transfer rates from the air.

Dry air inlet temperature 23.9 (t1) Wet air inlet temperature 20.5 (t2) Dry air outlet temperature 24.3 (13) Wet air outlet temperature 23.1 (14) Inlet (A) Outlet (B) Set 2 Set 1 T [°C] Inlet (A) Outlet (B) (b) By using the psychrometric chart, fill up the table below for mass balance. Set 1 v[m/kg dry w[kg/kg dry air] Inlet (A) Outlet (B) 0.0183 0.017 [kg/kg dry air] 61 Set 2 T [°C] 68 24.2 20.8 25.4 24.5 aur] 0.86 v[m³/kg dry air m (c) By using the psychrometric chart, fill up the table below for energy balance. het [kJ/kg dry air] het [kJ/kg dry air [kg dry air/s] 0.0586 m [kg dry air/s] 6

14-121 A laboratory has a volume of 700 m' and must have one complete air change per minute when being used. Outside atmospheric air at 100 kPa, 30°C dry bulb, and 60 percent rela- tive humidity is ducted into the laboratory air-conditioning equipment and conditioned to 20°C dry bulb and 12°C wet bulb, the required state for air supplied to the laboratory. (a) Sketch the system hardware and the psychrometric diagram for the process. (b) What outside atmospheric air mass flow rate is required for the air change, in kg/h? (c) Determine the mass flow rate of water condensed from the atmospheric air, in kg/min. (d) The cooling fluid in the air-conditioning system is chilled water, which has a 15°C temperature rise during the heat exchange process. Determine the chilled water mass flow rate, in kg/min.