Following calculator can be used to quickly calculate ‘Log Mean Temperature Difference’ or ‘LMTD’ for a shell & tube heat exchanger. This calculator uses the following simple formula to calculate LMTD.
ΔT1 → the temperature difference between hot and cold fluids at one end of the heat exchanger
ΔT2 → the temperature difference between hot and cold fluids at the other end of the heat exchanger.
However the LMTD is valid only for heat exchanger with one shell pass and one tube pass. For multiple number of shell and tube passes the flow pattern in a heat exchanger is neither purely co-current nor purely counter-current. Hence to account for geometric irregularity, Logarithmic Mean Temperature Difference (LMTD) has to be multiplied by a Mean Temperature Difference (MTD) correction factor to obtain the Corrected Mean Temperature Difference (Corrected MTD). Calculator presented here can be quickly used instead of MTD correction factor charts to determine the corrected MTD.