Design settings
Detailed method
One row per pipe run, fitting, valve or piece of equipment along the index circuit, from the pump discharge round to the pump suction. Pipe rows: pick the size and enter flow and length. Fittings take the row's size and flow; quantity goes in Length / Qty. Equipment: enter the pressure drop from the data sheet.
Quick method
Each column is one pipe section of the index circuit. Pick the size, enter flow and length, then how many of each fitting and valve are in that section.
Equipment
Chiller, coils, control and balancing valves on the index circuit. Enter the pressure drop from the manufacturer data sheet; the typical value is used until you do.
Design basis
Methods behind every number on this page. The same text is printed in the PDF report.
Water and pipe friction
Water properties at the mean CHW temperature (default 5.5 / 14.4 °C): density by the Thiesen equation, viscosity by the Vogel equation.
Velocity from the actual internal diameter of the chosen pipe (default steel Schedule 40). Darcy–Weisbach ΔP/L = (f/D)·ρV²/2 with the Colebrook friction factor, Re = ρVD/μ.
ASHRAE limits (Fundamentals, Pipe Sizing): velocity ≤ 1.2 m/s for 2 in (DN50) and smaller; friction ≤ 400 Pa/m above.
Fittings and valves
Equivalent length (default): Carrier System Design Manual, Part 3 – Piping Design, Table 10 (valves), Table 11 (fittings) and Table 12 (sudden enlargement / contraction, at the smaller size). ΔP = Le × friction rate of the row's pipe.
K-factor: ASHRAE pipe fitting tables (Hydraulic Institute data), screwed up to 2 in, flanged / welded above. ΔP = K·ρV²/2. Items missing from one table use the other, converted with K = f·Le/D; the row says so.
Equipment and total
Chiller evaporator, coils, control valves, balancing valves and heat exchangers from manufacturer data (typical values shown until entered).
Pump head = (pipe + fittings + equipment) × (1 + safety factor). Closed loop: static height is not added. Head in m = ΔP ÷ (ρ·g). Shaft power = Q × ΔP ÷ η.