Becasue of solar loads along with internal loads, many large buildings require cooling even if the outdoor temperature is lower than the indoor. Rather than running HVAC equipment for the purposes of cooling, it may be more economical to mix cooler outdoor air with the warmer indoor air. Assume a situation where 15,000 cfm of room air at 70F and 50% relative humitidy is taken from a building and circulated through a ducting system. Then 80% of this air (12,000 cfm) is mized with 3000 cfm of outdoor air at 60F and 35% relatve humidity (It should be noted that 3000cfm of the 15,000 cfm circulated air will then be discharged outdoors)

(a) What is the final temperature and relative humidity of the mixed air being discharged back to the room? (meaning, after the 3,000 cfm outdoor air combines with the 12,000 cfm indoor air)

(b) What is the cooling load (Btu/min) achieved by the use of outside air provided?

(c) If an air conditioner system with COP of 4 had been used to supply the cooling load (rather than using outdoor air) then what would be the daily cost of operating the A/C at $0.12 per kW*hr?