Cooling Tower Calculator
Cooling Tower Calculator
Process Conditions
Thermal Performance
Design is Feasible
Heat Load / Duty
---
kW
Cooling Tower Tons
---
TR
Range
---
°C
Approach
---
°C
Efficiency
---
%
Water Balance
Evaporation Loss
---
m³/hr
Blowdown Reqd.
---
m³/hr
Total Makeup Water
---
m³/hr
Technical Notes
Variable Definitions
- Q: Circulation flow rate (m³/hr or gpm).
- Tin: Hot water inlet temperature to tower (°C/°F).
- Tout: Cold water outlet temperature from tower (°C/°F).
- Twb: Ambient wet-bulb temperature at tower (°C/°F).
- Range = Tin − Tout.
- Approach = Tout − Twb.
- COC: Cycles of concentration (dimensionless), must be > 1.
- E: Evaporation loss (m³/hr or gpm).
- B: Blowdown (m³/hr or gpm).
- D: Drift loss (m³/hr or gpm).
- M: Makeup water (m³/hr or gpm) = E + B + D.
Formulas / Logic Used
- Range: Range = Tin − Tout
- Approach: Approach = Tout − Twb
-
Thermal duty:
- Metric: Heat (kcal/hr) = Q(m³/hr) × 1000 × Range(°C); Duty (kW) = Heat/860
- Imperial: Heat (Btu/hr) = Q(gpm) × 500 × Range(°F)
-
Cooling tower ton (TR):
- Metric: TR = Heat(kcal/hr) / 3024
- Imperial: TR = Heat(Btu/hr) / 15000 (cooling-tower ton basis)
- Efficiency: η = Range / (Range + Approach) × 100%
-
Evaporation loss (typical estimate):
- Imperial: E(gpm) = 0.00085 × Q(gpm) × Range(°F)
- Metric (equivalent): E(m³/hr) = 0.00153 × Q(m³/hr) × Range(°C)
- Drift: D = driftRate × Q (default driftRate = 0.00005 = 0.005%)
- Blowdown: B = E / (COC − 1)
- Makeup: M = E + B + D
Assumptions / Notes
- This is a preliminary sizing / screening calculator for duty and water balance. Final cooling tower selection should be confirmed with CTI/vendor performance curves and site-specific design data.
- Wet-bulb temperature should be the design wet-bulb for the location and season (meteorological data).
- Evaporation and drift formulas are rule-of-thumb estimates; actual values depend on tower type, air flow, fill, drift eliminators, and operating conditions.
- Typical economic designs have approach ~3–5°C (≈5–9°F). Very tight approach increases tower size sharply.
Built-in Logic Checks
- Range must be > 0: Tin must be greater than Tout.
- Approach must be ≥ 0: Tout cannot be below Twb for evaporative cooling.
- COC must be > 1: otherwise blowdown formula is invalid.