Method
Leaving dry-bulb temperature from entering dry-/wet-bulb temperatures and supplied effectiveness.
Equations
t2 = tdb − ε · (tdb − twb)
Δta = t2 − twb
Symbols and units
| Symbol | Quantity | Unit |
|---|---|---|
| Inputs | ||
| tdb | Entering dry bulb | °C |
| twb | Entering wet bulb | °C |
| ε | Cooler effectiveness | 0–1 |
| Results | ||
| t2 | Leaving dry bulb | °C |
| Δta | Approach to wet bulb | K |
Assumptions and limits
- Water consumption is not calculated.
In practice
- Take the effectiveness from the cooler manufacturer for the selected media and face velocity.
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
| tdb | Entering dry bulb | 30 °C |
| twb | Entering wet bulb | 20 °C |
| ε | Cooler effectiveness | 0.5 0–1 |
Results
| t2 | Leaving dry bulb | 25 °C |
| Δta | Approach to wet bulb | 5 K |
A preliminary check for engineer review, not an engineering approval. The project calculation to the applicable codes, authority requirements and specification governs.