that the perimeter of the heat exchanger is different on the hot and cold sides. The perimeter used for the does not matter as long as it is the same. The overall heat transfer coefficients will adjust to take into account that a different perimeter was used as the product will remain the same. The fouling resistances can be calculated for a specific heat exchanger if the average thickness and thermal conductivity of the fouling are known. The product of the average thickness and thermal conductivity will result in the fouling resistance on a specific side of the heat exchanger. = where: = average thickness of the fouling in a heat exchanger, = thermal conductivity of the fouling, . See also Convective heat transfer Heat sink Convection Churchill–Bernstein equation Heat Heat pump Heisler Chart Thermal conductivity Thermal-hydraulics Biot number Fourier number Nusselt number References External links Overall Heat Transfer Coefficients Overall Heat Transfer Coefficients Table and Equation Correlations for Convective Heat Transfer Convection Heat transfer Heat conduction