1. (35 pts) Using du ma@h the equal friction method, size the supply duct of a roof top unit, shown in Figure 1. The total pressure loss in the return air duct is 45 Pa. The ducts are to be of rectangular cross section and the maximum velocity in the main run is 5.5 m/s, whereas the branch velocities must not exceed 4.5 m/s. The maximum depth before the false ceiling is 40 cm. The outlet pressure drop in Pa is shown in the Figure next to each 2. outlets) Show the location of any required dampers and determine their resi r resistances if any. Compute the total pressure loss for the system assuming the lost pressure in the filter, furnace, and evaporator is 85 Pa. 202 3. (2 pts) Determine the fan power required for a fan efficiency of 90%. You can assume that the pressure drop in the return duct is 65% that of the supply duct and the resistance of the filter and johngama@buffale Cunit together is 150 Pa. Plenum 4 m 250 L/s 12.5 Pa 120 L/s 150 L/s 22 m Each branch turns down 90 deg 20m 9 Pa Fitting F1, F2, F7 F3, F4, F5 F6 Fs F 8 m 9m Fa 10m 8m 8m 20 m 10 Pa johngama@bujalo.eduay, 2023, 4:01:53 10 Pa 14m 120 L/s Figure 1 Supply Duct Layout 13 m 4 m 8 Pa 125 L/s Details 3-5 Elbow, Without Vanes, Rectangular (Idelchik et al. 1986, Diagram 6-1) 90, Sharp Throat Radius Heel (r/W-0.5 5-27 Tee, Diverging, Rectangular Main, and Tap (45 Entry) (SMACNA 1981, Table 6-10N) hnguffalo.edu May 203 5-23 Wye, Diverging, Rectangular and Round (Idelchik et al. 1986, Diagrams 7-15 and 7-17) 3-6 Elbow, Mitered, Rectangular (Idelchik et al. 1986, Diagram 6-5) F9 ma@buffalo Ma 2-10 Exit, Discharge to Atmosphere from a 90 Elbow, Rectangular and Round (Note: Elbow Loss Included) (delchik et al. 1986, Diagram 11-14) 17 PM EDT