Ductwork System Calculation Input Data Sheet

System/Zone Name: XYZ system Project: UVW-123456Designed by: Designer Date: 10/20/2009

Roughness e = 0.0003 [ - ]Air Density rho = 0.0763 [lbm/ft3] Specific Volume = 13.106

dp/100= 0.09 [inwc/100-ft] (Target pressure drop per 100')Kinevisc = 0.000163

Supply Air (SA) = 1,575 [CFM]Outdoor Air (OA) = 250 [CFM]

No. SA Segments = 6No. RA Segments = 6 Instruction:

Total Duct Segments = 12 1) 3) Run Macro 1: "fraction factor" in

fixture libraryfixture type, C, and dp input by user 4)

code Fixtures Fixture C dp [inwc] 1 fan out 0.72 2 el 0.113 tee thru 0.044 tee branch 0.85 fan in 0.3 OA SA6 diffuser 0.047 ret grille 0.03 RA

Duct Segment Input - For round ducts, input duct height as zero (0)Duct Seg. Air Flow Duct Height Duct Length fixture C or dp

No. cfm in ft code a code b code c code d1 1,575 14.0 20.0 1 2 32 1,185 12.0 15.0 33 985 12.0 22.0 3 24 535 10.0 8.0 4 25 385 10.0 12.0 36 85 0.0 20.0 4 67 72 0.0 20.0 7 3 28 324 10.0 12.0 39 450 10.0 8.0 4

10 829 12.0 22.0 3 211 997 12.0 15.0 312 1,325 14.0 20.0 5 3 213 14 1516

To run this program, fill in the input below, then go to sheet 1 and run the macro "friction factor". A further explanation of how this spreadsheet works is given on sheet 1. For guidance in selecting values for the input, consult the ASHRAE Handbook, Fundamentals, "Duct Design". This is Chapter 21 in the 2009 Handbook, but the chapter may be different in other editions. Data generated by sheets 1 and 2 will automatically be entered in the "Report" sheet.

Input blue cells in Input Tab,

Sheet 1 Tab,Print out Report in Report tab.

AHU

17181920212223242526272829303132

Duct System Pressure Drop Calculation Result System - Zone XYZ system

Project Number UVW-123456

Designer Designer

Date 10/20/2009

System/Zone Name: XYZ system Designed by: Designer Date: 10/20/2009

duct airflow height width dia velocity Re l'nth duct dp dp/100' vel. dp fix'tr dp tot. dp

leg Q H W D V Re L dP_duct dp/100' dP_v dP-fx dP_tot

No. [cfm] [in] [in] [in] [fpm] [ - ] [ft] [in. w.g.] [iw/100'] [in. w.g.] [in. w.g.] [in. w.g.]1 1,575 14 17 17 1,018 146,745 20.0 0.017 0.084 0.07 0.06 0.072 1,185 12 16 15 952 123,097 15.0 0.013 0.085 0.06 0.00 0.023 985 12 14 14 901 109,185 22.0 0.018 0.083 0.05 0.01 0.034 535 10 10 11 821 76,809 8.0 0.008 0.096 0.04 0.04 0.055 385 10 8 10 741 61,894 12.0 0.011 0.091 0.03 0.00 0.016 85 0 0.01 6 433 22,234 20.0 0.013 0.063 0.01 0.05 0.067 72 0 0.01 6 367 18,833 20.0 0.009 0.047 0.01 0.03 0.048 324 10 7 9 716 55,818 12.0 0.011 0.093 0.03 0.00 0.019 450 10 9 10 768 68,124 8.0 0.007 0.090 0.04 0.03 0.04

10 829 12 12 13 883 99,182 22.0 0.019 0.088 0.05 0.01 0.0311 997 12 14 14 912 110,515 15.0 0.013 0.085 0.05 0.00 0.0112 1,325 14 15 16 968 131,290 20.0 0.017 0.083 0.06 0.03 0.04

0.155 0.26 0.41

DUCT SIZE CALCULATION SPREADSHEET Run macro "friction factor"Project UVW-123456 system-zone XYZ system fixture library

<-- input data from Input tab fixture type, C, and dp input by userformulas: code Fixtures Fixture C dp [inwc]

Reynolds Number Re = 8.56*D*V fixed parameters (user input) 1 fan out 0.72 0D=(1.3(a*b)^.625)/(a+b)^.25 Roughness e = 0.0003 [ - ] 2 el 0.11 0V=Q/((Pi*D^2/4)/144) Air Density rho = 0.0763 [lbm/ft3] 3 tee thru 0.04 0

Target dp/100' = 0.090 [inwc/100-ft] 4 tee branch 0.8 0Colbrook 1/f^.5 = -2*log(12*e/3.7/D+2.51/Re/f^.5) kinevisc = 0.000163 5 fan in 0.3 0

dp = (12*f*L*rho*(V/1097)^2)/D Zone air flow = 1575 [CFM] 6 diffuser 0 0.04Zone outdoor air = 250 [CFM] 7 ret grille 0 0.03

Fixture Loss vdp = rho*(V/1097)^2 specific volume = 13.106fixdp = vdp*C or fixdp = dp from fixture library

All data below calculated by macro except fixture codes, which are input by the userbranch count max = 12 This macro will clear the contents of all calculated cells. The fixture loss input cells, N32 - Q100 will not be cleared

duct leg airflow Q height a width b dia D V Re L duct dp dp/100' vdp fixdp systotdp fixture C or dpcfm in in in fpm ft iw iw/100' iw iw iw coda codb codc codd

1 1575 14 17.0 16.8 1018 146745 20 0.017 0.084 0.066 0.057 0.074 1 2 3 02 1185 12 16.0 15.1 952 123097 15 0.013 0.085 0.057 0.002 0.015 3 0 0 03 985 12 14.0 14.2 901 109185 22 0.018 0.083 0.051 0.008 0.026 3 2 0 04 535 10 10.0 10.9 821 76809 8 0.008 0.096 0.043 0.039 0.047 4 2 0 05 385 10 8.0 9.8 741 61894 12 0.011 0.091 0.035 0.001 0.012 3 0 0 06 85 0 0.0 6.0 433 22234 20 0.013 0.063 0.012 0.050 0.062 4 6 0 07 72 0 0.0 6.0 367 18833 20 0.009 0.047 0.009 0.031 0.041 7 3 2 08 324 10 7.0 9.1 716 55818 12 0.011 0.093 0.032 0.001 0.012 3 0 0 09 450 10 9.0 10.4 768 68124 8 0.007 0.090 0.037 0.030 0.037 4 0 0 0

10 829 12 12.0 13.1 883 99182 22 0.019 0.088 0.049 0.007 0.027 3 2 0 011 997 12 14.0 14.2 912 110515 15 0.013 0.085 0.053 0.002 0.015 3 0 0 012 1325 14 15.0 15.8 968 131290 20 0.017 0.083 0.059 0.027 0.043 5 3 2 0

0 0 00.155 0.256 0.411 0 0 0

0 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 0 0 0

After the input sheet is completed, the size of each duct segment that will give the exact desired pressure loss per 100 feet of duct length. If a height is imput, the exact width corresponding to the height and hydraulic diameter is also given. There is no need for the user to reference sheet two except to verify results. For convenience, the branch flow rates are also shown on sheet 2.

In the real world, there are no decimal fractions in duct diameters or the width of rectanglular ducts. Also, the objective is to calculate the external static pressure for a fan or air handler. Therefore, the user must run the macro "friction factor" on sheet 1. This macro rounds the diameter of round ducts, or the width of rectanglular ducts to the nearest inch. If the duct is rectangular, the macro recalculates the hydraulic diamter to correspond to the new width. Velocity (V) and pressure loss per 100' (dp/100') is then recalculated for the new hydraulic or integer duct diameter (dia D). Duct friction loss for each segment is calculated and totaled (duct dp). Fixture loss (fixdp), based on loss coefficients or pressure losses from ASHRAE data and manufacturer's performance data, is calculated based on the fixtures input from the sheet Input. Finally, the external static pressure (systotdp) is calculated and totaled.

0 0 0 00 0 0 0

ProjectSystem-Zone green cell: input data from Input sheetcalculation date shaded cell: calculated by UDF or formula

Duct Size and Rectangular/round duct conversion

supply air flow = 1575.0 cfm dp100 = 0.090 return segments: outdoor air flow = 250.0 oacfm e = 0.0003

return air flow = 1325.0 rcfm rho = 0.0763 spvol= 13.106kinevisc = 0.000163

subcountmax = 6 supply duct segments return segments =D=(1.3(a*b)^.625)/(a+b)^.25 Curve fit of dia for dp100=.095 (first guess): D=alog(.38352*log(cfm) + .00864)

airflow height dia width dp100 branch sbrcount Lcfm in in in iw/100' cfm ft

1,575.0 14.0 #VALUE! #VALUE! #VALUE! 1.0 20.01,185.0 12.0 #VALUE! #VALUE! #VALUE! 390.0 2.0 15.0985.0 12.0 #VALUE! #VALUE! #VALUE! 200.0 3.0 22.0535.0 10.0 #VALUE! #VALUE! #VALUE! 450.0 4.0 8.0385.0 10.0 #VALUE! #VALUE! #VALUE! 150.0 5.0 12.085.0 0.0 #VALUE! 0.0 #VALUE! 300.0 6.0 20.072.0 0.0 #VALUE! 0.0 #VALUE! 0.0 7.0 20.0

324.0 10.0 #VALUE! #VALUE! #VALUE! 0.0 8.0 12.0450.0 10.0 #VALUE! #VALUE! #VALUE! 0.0 9.0 8.0829.0 12.0 #VALUE! #VALUE! #VALUE! 0.0 10.0 22.0997.0 12.0 #VALUE! #VALUE! #VALUE! 0.0 11.0 15.0

1,325.0 14.0 #VALUE! #VALUE! #VALUE! 0.0 12.0 20.00.0 0.0 0.0 13.0 0.0 0.0 0.0 14.0 0.0 0.0 0.0 15.0 0.00.0 0.0 0.0 16.0 0.00.0 0.0 0.0 17.0 0.00.0 0.0 0.0 18.0 0.00.0 0.0 0.0 19.0 0.00.0 0.0 0.0 20.0 0.00.0 0.0 0.0 21.0 0.00.0 0.0 0.0 22.0 0.00.0 0.0 0.0 23.0 0.00.0 0.0 0.0 24.0 0.00.0 0.0 0.0 25.0 0.00.0 0.0 0.0 26.0 0.00.0 0.0 0.0 27.0 0.00.0 0.0 0.0 28.0 0.00.0 0.0 0.0 29.0 0.00.0 0.0 0.0 30.0 0.00.0 0.0 0.0 31.0 0.00.0 0.0 0.0 32.0 0.0

return segments: 0 means returns correspond to supply segments> 0 means returns are entered by user

return segments = 6D=alog(.38352*log(cfm) + .00864)

module 1 friction factor macromodule 111 fcalc UDFmodule 12 AirCap UDFmodule 21 Air Dia UDFmodule 31 Wcalc UDFmodule 51 AirPd UDF