The formula to calculate Log Mean Temperature Difference is:
\[ \text{LMTD} = \frac{(\text{Tho} - \text{Tci}) - (\text{Thi} - \text{Tco})}{\ln \left( \frac{\text{Tho} - \text{Tci}}{\text{Thi} - \text{Tco}} \right)} \]
The Log Mean Temperature Difference (LMTD) is a logarithmic average of the temperature difference between the hot and cold streams at each end of the exchanger. Outlet Temperature of Hot Fluid is the temperature at which the hot fluid exits the heat exchanger. Inlet Temperature of Cold Fluid is the temperature at which the cold fluid enters the heat exchanger. Inlet Temperature of Hot Fluid is the temperature at which the hot fluid enters the heat exchanger. Outlet Temperature of Cold Fluid is the temperature at which the cold fluid exits the heat exchanger.
Let's assume the following values:
Using the formula:
\[ \text{LMTD} = \frac{(20 - 5) - (35 - 10)}{\ln \left( \frac{20 - 5}{35 - 10} \right)} \approx 19.5761518897122 \, \text{Kelvin} \]
The Log Mean Temperature Difference is approximately 19.5761518897122 Kelvin.
| Outlet Temperature of Hot Fluid (Kelvin) | Log Mean Temperature Difference (Kelvin) |
|---|---|
| 15 | 16.370350019059373 |
| 16 | 17.052779100191401 |
| 17 | 17.711915488248533 |
| 18 | 18.350687115616378 |
| 19 | 18.971454153426620 |
| 20 | 19.576151889712175 |
| 21 | 20.166390529760477 |
| 22 | 20.743526783203219 |
| 23 | 21.308716401967331 |
| 24 | 21.862953513612382 |
| 25 | 22.407100588622754 |