A counter-flow heat exchanger has a heat transfer area of 15 m² and an overall heat transfer coefficient of 500 W/(m²·K). The hot fluid cools from 80 to 40 °C and the cold fluid heats from 20 to 40 °C. Find the heat transfer rate Q̇.
Hot oil (0.5 kg/s, cp = 2.3 kJ/(kg·K)) cools from 120 to 55 °C in a counter-flow exchanger. It heats 3 kg/s of water (cp = 4.18 kJ/(kg·K)) that enters at 10 °C. No heat is lost to the surroundings. Find the water outlet temperature Tc,out.
In a condenser, steam condenses at a constant 110 °C on the outside of the tubes. Cooling water (2 kg/s, cp = 4.18 kJ/(kg·K)) flows through the tubes and heats from 25 to 50 °C. The overall heat transfer coefficient is 3000 W/(m²·K). Find the heat transfer area A needed.
A parallel-flow heat exchanger transfers 490 kW. Its heat transfer area is 3 m². The hot fluid cools from 125 to 105 °C and the cold fluid heats from 15 to 80 °C. Find the overall heat transfer coefficient U.
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 140 to 70 °C. Water (0.2 kg/s, cp = 4.18 kJ/(kg·K)) in the annulus enters at 25 °C. The inner tube has a diameter of 32 mm, and U = 400 W/(m²·K) is based on this diameter. Find the tube length L needed.
In a parallel-flow double-pipe heat exchanger, hot oil (0.3 kg/s, cp = 2.3 kJ/(kg·K)) flows in the inner tube and cools from 130 to 60 °C. Water (1 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 = 250 W/(m²·K) is based on this diameter. Find the tube length L needed.
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