Total heat rejection capacity in refrigeration tons (1 ton = 12,000 BTU/hr). If omitted, heat_rejection_kw must be provided instead.

Total heat rejection capacity in kilowatts (1 ton = 3.517 kW). If omitted, heat_rejection_tons must be provided instead.

Cooling tower configuration. 'induced_draft_counterflow' is most common for large HVAC/datacenter applications. Affects fan power, drift rate, and performance characteristics. If omitted, defaults to 'induced_draft_counterflow'.

Design outdoor wet-bulb temperature in degrees Fahrenheit. Use ASHRAE 0.4% or 1% design condition for your location. Typical US range: 72-80 F. If omitted, defaults to 78 F.

Temperature difference between the cold water leaving the tower and the design wet-bulb temperature, in degrees F. Lower approach requires a larger/costlier tower. Typical: 5-10 F. If omitted, defaults to 7 F.

Temperature difference between the hot water entering and cold water leaving the tower, in degrees F. Standard condenser water delta-T is 10 F for HVAC systems. Typical: 10 F for HVAC, 15-25 F for industrial, 10 F at 3 GPM/ton. If omitted, defaults to 10 F.

Condenser water flow rate in gallons per minute. Typical: 3 GPM/ton. If omitted, calculated from heat rejection and range using Q = 500 * GPM * delta-T.

Number of cooling tower cells. If provided, uses this cell count instead of calculating from heat load and table data. If omitted, calculated from heat load and nominal tons per cell from the tower performance table.

Ratio of dissolved solids in blowdown water to makeup water. Higher CoC reduces makeup water but requires better water treatment. Typical: 3-7 for open recirculating systems. If omitted, defaults to 5.0.