A thin-walled double-pipe, counter-flow heat exchanger is to be used to cool oil (cp = 0.525 Btu/lbm·°F) from 300°F to 105°F at a rate of 5 lbm/s by water (cp = 1.0 Btu/lbm·°F) that enters at 70°F at a rate of 3 lbm/s. The diameter of the tube is 5 in and its length is 200 ft. Determine the overall heat transfer coefficient of this heat exchanger using (a) the LMTD method and (b) the «-NTU method.

With reference to the schematic below, a thin-walled double-pipe counter-flow heat exchanger is to be used to cool a hot fluid (cp=2200 J/kg.°C) from 150°C to 50°C at a rate of 2 kg/s by water (cp = 4180 J/kg°C) that enters at 22°C at a rate of 1.5 kg/s. The diameter of the tube is 2.5 cm, and its length is 6 m. Determine the overall heat transfer coefficient, U of this heat exchanger. Hot fluid 150°C Cold water 22°C 150°C Assumptions: 1.Steady operating conditions exist. 2 The heat exchanger is well-insulated so that heat loss to the surroundings is negligible.

A thin-walled double-pipe counter-flow heat exchanger is to be used to cool oil (Cpo= 2200 J/kg.K) from 150°C to 40°C at a rate of 2 kg/s by water (Cpw= 4180 J/kg.K) that enters at 22°C at a rate of 1.5Kg/s. If the diameter of the tube is 2.5 cm, and its length is 6 m, determine * The rate of heat transfer in the heat exchanger * The outlet temperature of the cold fluid * The Log Mean Temperature Difference (LMTD) * The overall heat transfer coefficient

A long, thin-walled double-pipe heat exchanger with tube and shell diameters of 0.01 m and 0.025 m, respectively, is used to condense refrigerant-134a with water at 20°C. The refrigerant flows through the tube, with a convection heat transfer coefficient of hi= 4100 W/m² °C. Water flows through the shell at a rate of 0.3 kg/s. The thermal resistance of the inner tube is negligible since the tube material is highly conductive and its thickness is negligible. Both the water and refrigerant-134a flows are fully developed. Properties of the water and refrigerant-134a are constant. Water properties: p = 998 kg/m³, v=u/p-1.004x 10-6 m²/s, k = 0.598 W/m. °C, Pr = 7.01 Cold water D Do