Cooling Tower Calculator
Cooling Tower Calculator
Process Conditions
Thermal Performance
Design is Feasible
Heat Load / Duty
---
kW
Cooling Tower Tons
---
TR
Range
---
Β°C
Approach
---
Β°C
Efficiency
---
%
Water Balance
Evaporation Loss
---
mΒ³/hr
Blowdown Reqd.
---
mΒ³/hr
Total Makeup Water
---
mΒ³/hr
Technical Notes
Variable Definitions
- Q: Circulation flow rate (mΒ³/hr or gpm).
- Tin: Hot water inlet temperature to tower (Β°C/Β°F).
- Tout: Cold water outlet temperature from tower (Β°C/Β°F).
- Twb: Ambient wet-bulb temperature at tower (Β°C/Β°F).
- Range = Tin β Tout.
- Approach = Tout β Twb.
- COC: Cycles of concentration (dimensionless), must be > 1.
- E: Evaporation loss (mΒ³/hr or gpm).
- B: Blowdown (mΒ³/hr or gpm).
- D: Drift loss (mΒ³/hr or gpm).
- M: Makeup water (mΒ³/hr or gpm) = E + B + D.
Formulas / Logic Used
- Range: Range = Tin β Tout
- Approach: Approach = Tout β Twb
-
Thermal duty:
- Metric: Heat (kcal/hr) = Q(mΒ³/hr) Γ 1000 Γ Range(Β°C); Duty (kW) = Heat/860
- Imperial: Heat (Btu/hr) = Q(gpm) Γ 500 Γ Range(Β°F)
-
Cooling tower ton (TR):
- Metric: TR = Heat(kcal/hr) / 3024
- Imperial: TR = Heat(Btu/hr) / 15000 (cooling-tower ton basis)
- Efficiency: Ξ· = Range / (Range + Approach) Γ 100%
-
Evaporation loss (typical estimate):
- Imperial: E(gpm) = 0.00085 Γ Q(gpm) Γ Range(Β°F)
- Metric (equivalent): E(mΒ³/hr) = 0.00153 Γ Q(mΒ³/hr) Γ Range(Β°C)
- Drift: D = driftRate Γ Q (default driftRate = 0.00005 = 0.005%)
- Blowdown: B = E / (COC β 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 ~3β5Β°C (β5β9Β°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 β₯ 0: Tout cannot be below Twb for evaporative cooling.
- COC must be > 1: otherwise blowdown formula is invalid.