Method
Basic cooling-tower heat rejection from water mass flow, specific heat and range.
Equations
R = thw − tcw
Q = ṁ · cp · R
Symbols and units
| Symbol | Quantity | Unit |
|---|---|---|
| Inputs | ||
| ṁ | Water mass flow | kg/s |
| cp | Water specific heat | kJ/kg·K |
| thw | Hot-water temperature | °C |
| tcw | Cold-water temperature | °C |
| Results | ||
| R | Range | K |
| Q | Heat rejection | kW |
Assumptions and limits
- Approach, evaporation, drift, blowdown and cycles of concentration are excluded.
Worked example
The input values are the calculator's own verification test, run through the calculator. They show the working; they are not design values.
Inputs
| ṁ | Water mass flow | 2 kg/s |
| cp | Water specific heat | 4 kJ/kg·K |
| thw | Hot-water temperature | 40 °C |
| tcw | Cold-water temperature | 30 °C |
Results
| R | Range | 10 K |
| Q | Heat rejection | 80 kW |
A preliminary check for engineer review, not an engineering approval. The project calculation to the applicable codes, authority requirements and specification governs.