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

Question

Quizplus · Accepted Answer

The log mean temperature difference (LMTD) for a counterflow heat exchanger is calculated using the formula: LMTD = (ΔT1 - ΔT2) / ln(ΔT1/ΔT2), where ΔT1 and ΔT2 are the temperature differences at each end of the heat exchanger. For this scenario, ΔT1 = 250°C - 150°C = 100°C and ΔT2 = 200°C - 50°C = 150°C. Plugging these values into the formula gives an LMTD closer to 128°C.

A Liquid to Liquid Counterflow Heat Exchanger Is Used to Heat