Evaporation Load Calculator
Calculate heat loss and cooling requirements quickly. Estimate energy loss due to evaporation for pools, cooling towers, and industrial systems.
Heat Loss Estimator
How to Use an Evaporation Load Calculator
Follow these simple steps to use an evaporation load calculator effectively:
- 1Enter the surface area of the liquid (in m² or ft²). This defines the exposed area where evaporation occurs.
- 2Input the temperature of the liquid (°C or °F). Higher temperatures increase evaporation rates.
- 3Enter the ambient air temperature and humidity. These factors directly affect evaporation speed.
- 4Provide air velocity over the surface (m/s or ft/s). Faster air increases evaporation.
- 5Click "Calculate" to get the evaporation load. The result shows heat loss in kW, BTU/hr, or kcal/hr.
Tip: Always use consistent units for accurate results.
How to Calculate Evaporation Load
Evaporation load represents the heat required to evaporate water from a surface. This process removes energy from the liquid, resulting in a cooling effect.
Basic Formula
The evaporation load is calculated by multiplying the mass of evaporated water by the latent heat of vaporization:
Where:
- m = mass of evaporated water (kg/s)
- h_fg = latent heat of vaporization (typically 2260 kJ/kg for water)
Step-by-Step Example
Suppose you have the following conditions:
- Surface area = 10 m²
- Evaporation rate = 0.2 kg/m²·hr
- Latent heat = 2260 kJ/kg
Step 1: Calculate total evaporation rate (mass per hour)
m = 10 × 0.2 = 2 kg/hr
Step 2: Convert to kg/s
m = 2 / 3600 = 0.00056 kg/s
Step 3: Calculate evaporation load
Q = 0.00056 × 2260 = 1.27 kW
Final Answer: Evaporation Load = 1.27 kW
Evaporation Load Conversion Chart
Use this chart to convert results into your required unit instantly:
| Evaporation Load | kW | BTU/hr | kcal/hr |
|---|---|---|---|
| 1 kW | 1 | 3412 | 860 |
| 2 kW | 2 | 6824 | 1720 |
| 5 kW | 5 | 17060 | 4300 |
| 10 kW | 10 | 34120 | 8600 |
| 20 kW | 20 | 68240 | 17200 |
Quick Tip: 1 kW is approximately 3412 BTU/hr or 860 kcal/hr.
Frequently Asked Questions (FAQs)
An evaporation load refers to the amount of heat energy required to evaporate water from surfaces, such as indoor swimming pools, industrial tanks, or cooling towers. HVAC systems must account for this latent heat load to properly manage indoor humidity levels and prevent excessive condensation.
Calculating an evaporation load involves the water surface area, water temperature, ambient air temperature, and the velocity of air moving over the surface. These variables determine the rate at which water turns into vapor, which dictates the system's required dehumidification capacity.
For indoor swimming pools, the evaporation load is immense. If the HVAC system cannot handle the massive amount of water vapor released, the facility will suffer from oppressive humidity, uncomfortable conditions, and severe structural damage due to constant and corrosive condensation.
Air velocity plays a huge role in evaporation rates. Faster-moving air sweeps away the saturated air directly above the water's surface, replacing it with drier air and accelerating evaporation. This increased rate significantly adds to the latent load on the facility's HVAC dehumidification system.
Yes, water temperature drastically changes the evaporation load. Warmer water has a higher vapor pressure, causing it to evaporate much more rapidly than cooler water. This is why heated pools and spas generate significantly more humidity and require larger, specialized dehumidification systems.
