Evaporation from a Water Surface

Calculator for water evaporation from open surfaces like pools and tanks. Computes evaporated water amount and required heat supply based on water temperature, air conditions, and surface parameters.

Evaporation from a Water Surface Calculator

Calculate the amount of evaporated water and required heat supply from an open water surface based on:

Evaporation Formula:

gh = Θ × A × (xs - x)
- gh = amount of evaporated water per hour (kg/h)
- Θ = (25 + 19v) = evaporation coefficient (kg/m²h)
- A = water surface area (m²)
- xs = maximum humidity ratio of saturated air at water temperature (kg/kg)
- x = humidity ratio of air (kg/kg)

Heat Supply Formula:

q = hwe × gs
- q = heat supplied (kW)
- hwe = evaporation heat of water (kJ/kg)
- gs = evaporated water per second (kg/s)

Calculator

Inputs

Water Temperature (°C)

Air Velocity Above Water Surface (m/s)

Water Surface Area (m²)

Maximum Saturation Humidity Ratio (xs) (kg/kg)

Air Humidity Ratio (x) (kg/kg)

Evaporation Heat of Water (kJ/kg)

Results

Evaporation Coefficient (Θ)-- kg/m²h

Humidity Ratio Difference (xs - x)-- kg/kg

Evaporated Water per Hour (gh)-- kg/h

Evaporated Water per Second (gs)-- kg/s

Required Heat Supply (q)-- kW

Required Heat Supply-- Btu/h