Perform the calculations requested that pertain to an air distribution system for a single family residence with a floor area of about 2,000 to 3,000 sq. ft. with an airflow of 1000cfm through the ducting, fan and HXs.
1a. Based on an air velocity of 15 ft/s, calculate the size of a square duct. Repeat for a rectangular duct with an aspect ratio of 2.0 ( width divided by height ). Also calculate the hydraulic diameter for both.
1b. Assume a friction factor of 0.015 and calculate the pressure drop ( inches of water and psi ) for 200 ft of ducting ( which could also include equivalent lengths in the case of minor losses being added in ). Calculate the ideal power for a fan to deliver this flow and for a real fan with an efficiency of 60%. Repeat these calculations for 600 ft of ducting
1c. Calculate a friction factor for both the square and rectangular duct and compare to the above.
1d. For a 3 ton A/C , what is the temperature drop through the evaporator?