Log mean temperature difference (LMTD) cannot be used, if

Related MCQs

• In a parallel flow heat exchanger, if the outlet temperature of hot and cold fluids are the same, then the log mean temperature difference (LMTD) is
• In a liquid-liquid heat exchanger, for the same process temperature, the ratio of the LMTD in parallel flow to the LMTD in counter flow is always
• Out of the following four assumptions used in the derivation of the equation for LMTD [LMTD = (∆t1 - ∆t2)/ln(∆t1/∆t2)], which one is subject to the largest deviation in practice ?
• A liquid to liquid counterflow heat exchanger is used to heat cold fluid from 50?C to 150?C. Assuming that the hot fluid enters at 250?C and leaves at 200?C, the log mean temperature difference for the heat exchanger will be closer to
• Log mean temperature difference in case of counter flow compared to parallel flow will be
• Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3 /min) of density 800 kg/m3 and specific heat of 2 kJ/kg.K enters at 20°C. The log mean temperature difference in °C is approximately
• In a 1-1 concurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is
• A wall has two layers of materials A and B; each made of a different material. Both the layers have the same thickness. The thermal conductivity of material A is twice that of B. Under the equilibrium, the temperature difference across the wall is 36°C. The temperature difference across the layer A is __________ °C.
• LMTD can't be used as such without a correction factor for the
• Harmonic mean temperature difference is given by