Thermal resistance due to fouling deposits (general)
Description
Often during their use, heat exchangers collect a layer of fouling on the surface which, in addition to potentially contaminating a stream, reduces the effectiveness of heat exchangers. In a fouled heat exchanger the buildup on the walls creates an additional layer of materials that heat must flow through. Due to this new layer, there is additional resistance within the heat exchanger and thus the overall heat transfer coefficient of the exchanger is reduced. The relationship shown here is used to solve for the heat transfer resistance with the additional fouling resistance.
Related formulasVariables
| Uf | overall heat transfer coefficient for a fouled heat exchanger (W/m2*K) |
| P | perimeter of the heat exchanger (m) |
| U | overall heat transfer coefficient for an unfouled heat exchanger (W/m2*K) |
| RfH | fouling resistance on the hot side of the heat exchanger (m2*K/W) |
| PH | perimeter of the hot side of the heat exchanger (m) |
| RfC | fouling resistance on the cold side of the heat exchanger (m2*K/W) |
| PC | perimeter of the cold side of the heat exchanger (m) |