(e.g., "14x10 Supply Duct", "90 Degree Elbow") Quantity: Number of items. Pressure Drop (in. w.c.): Resistance value. Total Drop (in. w.c.): Quantity × Pressure Drop Example Calculation Table Drop (in. w.c.) Total (in. w.c.) Return Air Grille Return Ductwork (Equiv. Length) Filter (MERV 11) Evaporator Coil Supply Ductwork (Equiv. Length) Supply Registers Total ESP 0.87 in. w.c. 4. Steps to Use the Excel Sheet 1. Identify Target CFM
[Manual Benchmark Calc] vs [Excel Sheet Output] ➔
Since most main duct runs are rectangular, you must convert rectangular dimensions ( ) to an hydraulically equivalent round diameter ( Decap D sub e ) using the : esp calculation hvac excel sheet
[Step 1: Path Selection] ➔ [Step 2: Sectioning] ➔ [Step 3: Component Inventory] ➔ [Step 4: Data Entry] Step 1: Identify the Critical Path
Create reference tables so your main sheet can use dropdown menus. Total Drop (in
De=1.30×(a×b)0.625(a+b)0.25cap D sub e equals the fraction with numerator 1.30 cross open paren a cross b close paren to the 0.625 power and denominator open paren a plus b close paren to the 0.25 power end-fraction
If you want, I can generate a ready-to-download Excel (.xlsx) with these tabs and example formulas. unit tags (e.g.
The fan cannot overcome the actual system resistance. Airflow drops, spaces become uncomfortable, and DX coils can freeze.
Set up warning flags using conditional formatting. For example, highlight velocity cells in light red if the value exceeds 1,500 FPM for branch ducts or 2,500 FPM for main headers to keep noise within acceptable limits.
Here is how to write the actual formulas.
: Fields for project name, unit tags (e.g., AHU-01), and design airflow (CFM or Duct Friction Loss