Condensation of Steam
Steam is frequently used as heating medium. The mean temperature difference is given here: A pure, saturated, vapour will condense at a fixed temperature, at constant pressure. For an isothermal process such as this, the simple LMTD can be used in equation 1.3; no correction factor for multiple passes is needed. The LMTD will be given by:
ΔT m = (t2 – t1) (eq. 1.34)
Where T sat = saturation temperature of the vapour,
t1 = inlet coolant temperature,
t2 = outlet coolant temperature.
When the condensation process is not exactly isothermal but the temperature change is small; such as where here is a significant change in pressure; the LMTD can still be used but the temperature correction factor will be needed for multipass condensers. The appropriate terminal temperatures should be used in the calculation.