A counter-flow heat exchanger has a heat transfer area of 8 m² and an overall heat transfer coefficient of 1500 W/(m²·K). The hot fluid cools from 110 to 45 °C and the cold fluid heats from 20 to 90 °C. Find the heat transfer rate Q̇.
In a counter-flow heat exchanger the hot fluid cools from 175 to 35 °C while the cold fluid heats from 10 to 20 °C. Find the log-mean temperature difference ΔTlm.
A shell-and-tube heat exchanger (one shell pass, two tube passes) must transfer 670 kW. The hot fluid cools from 135 to 80 °C and the cold fluid heats from 25 to 90 °C. The LMTD correction factor for this arrangement is F = 0.88, and U = 200 W/(m²·K). Find the heat transfer area A needed.
A shell-and-tube heat exchanger (one shell pass, two tube passes) must transfer 390 kW. The hot fluid cools from 130 to 110 °C and the cold fluid heats from 20 to 85 °C. The LMTD correction factor for this arrangement is F = 0.85, and U = 500 W/(m²·K). Find the heat transfer area A needed.
Hot oil (2 kg/s, cp = 2.3 kJ/(kg·K)) cools from 145 to 55 °C in a counter-flow exchanger. It heats 1.5 kg/s of water (cp = 4.18 kJ/(kg·K)) that enters at 25 °C. With U = 200 W/(m²·K), find the heat transfer area A needed.
In a counter-flow double-pipe heat exchanger, hot oil (0.5 kg/s, cp = 2.3 kJ/(kg·K)) flows in the inner tube and cools from 95 to 65 °C. Water (0.2 kg/s, cp = 4.18 kJ/(kg·K)) in the annulus enters at 15 °C. The inner tube has a diameter of 50 mm, and U = 300 W/(m²·K) is based on this diameter. Find the tube length L needed.
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