1. 2,000 cfm outside air at 97F dry bulb temperature and 77F wet bulb temperature is mixed with 18,000 cfm return air at 75F and 50% relative humidity. Find the mixing air condition. Mark the states of the two airstreams and the mixing air state. Check if the three points are co-linear. (15) 2. The mixing process in problem 1 is followed by a cooling & dehumidifying process to 58F dry bulb temperature and 80% relative humidity. The condensate water leaves at 55F. Find the cooling coil load. Draw the air process lines on the same psychrometric chart for processes in problem 1 and problem 2. (15) 3. Moist air at 60F dry bulb temperature and 20% relative humidity enters a heater and humidifier at the rate of 1600 cfm. Heating of the air is followed by an adiabatic humidification. Heating coil provides heat to the moist air at heat transfer rate of 90,500 Btu/hr. For adiabatic humidification process, saturated water vapor at 212F is injected at the mass flow rate of 125 Ibmv/h. Find the condition of air leaving the humidifier. (20) 4. An evaporative cooler is able to cool air by 85 percent of the difference between the entering air dry-and wet-bulb temperatures. If inlet air is at 38°C and 25 percent relative humidity, what is the outlet condition (Td, q, and W)? How much water is evaporated if the airflow is 4700 L/s? (15)