For the system described in Problem 13.35, what total pressure for the system is required to maintain 1000 ft 3 /min when the filter is dirty? Problem 13.35 The 2 ft × 2 ft galvanized steel duct shown...

For the system described in Problem 13.35, what total pressure for the system is required to maintain 1000 ft³/min when the filter is dirty?

Problem 13.35

The 2 ft × 2 ft galvanized steel duct shown in Figure P13.5 carries 1000 ft³/min of air at 70°F when the filter is new. The filter pressure drop is 0.25 in. H₂O when new and should be changed when it is 0.75 in. H₂O. What is the volume flowrate when the filter is changed?