| Fitting | Equivalent length (m) per 100 mm pipe dia | |---------|-------------------------------------------| | 90° elbow | 0.3 – 0.6 | | Tee (straight) | 0.6 – 1.2 | | Tee (branch) | 1.5 – 2.4 | | Gate valve (open) | 0.15 – 0.3 | | Globe valve (open) | 6 – 10 | | Swing check valve | 2 – 4 | | Strainer | 3 – 6 | Darcy-Weisbach (more accurate):
h_f = f × (L_eq / D) × (v² / (2g))
Common equivalent lengths (for water, schedule 40 steel pipe): chilled water pump head calculation excel sheet
L_eq = L_pipe + Σ (N_fitting × L_fitting_eq) | Fitting | Equivalent length (m) per 100
In Excel, convert all to consistent units. Worksheet: Pump Head Calculator | A | B | C | D | |---|---|---| | Input Data | | Value | Unit | | Flow rate (Q) | | 100 | m³/hr | | Pipe length (straight) | | 150 | m | | Pipe inner diameter | | 150 | mm | | Pipe roughness (ε) | | 0.15 | mm | | No. of 90° elbows | | 12 | | | No. of gate valves | | 4 | | | No. of strainers | | 1 | | | Chiller drop | | 60 | kPa | | Coil drop | | 30 | kPa | | Control valve drop | | 10 | kPa | | Elevation difference (if open system) | | 0 | m | of gate valves | | 4 | | | No
1. Objective To provide a structured, reusable Excel-based method for calculating the total dynamic head (TDH) of a chilled water pump in a closed-loop HVAC system. Accurate head calculation ensures proper pump selection, energy efficiency, and system reliability. 2. Key Parameters for Pump Head Calculation In a closed chilled water system, the total head (in meters or feet) is the sum of: