A shell-and-tube heat exchanger with 1-shell pass and 20–tube passes is used to heat glycerin in the shell, with hot water in the tubes. The tubes are thin-walled and have a diameter of 4 cm and length of 2 m per pass. The water enters the tubes at 1000C at a rate of 0.5 kg/s and leaves at 550C. The glycerin enters the shell at 150C and leaves at 550C. Determine the mass flow rate of the glycerin and the overall heat transfer coefficient of the heat exchanger.

5-84 Air (Cp=1.005 kJ/kg°C) is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. Air enters the heat exchanger at 95 kPa and 20°Ct at rate of 0.6 m³/s. The combustion gases (Cp=1.10 kJ/kg°C) that enter at 160°C at a rate of 0.95 kg/s and leave at 95°C. Determine the rate of heat transfer to the air and its outlet temperature. Air 95 kPa 20°C 0.6 m³/s Exhaust gases 0.95 kg/s 95°C

Cold water (cp = 4180 J/kg×K) leading to a shower enters a thin-walled double-pipe counterflow heat exchanger at 15°C at a rate of 0.25 kg/s and is heated to 45°C by hot water (cp = 4190 J/kg×K) that enters at 100°C at a rate of 3 kg/s. If the overall heat transfer coefficient is 950 W/m2×K, determine the rate of heat transfer and the heat surface area of the heat exchanger using the effectiveness–NTU method.

A long counter-flow heat exchanger cools water from 40°C to 10°C by passing the water via the inner tube through an enclosure of cold fluid. The water is flowing through a 3-cm diameter tube at a rate of 0.27 kg/s. The cold fluid enters the enclosure at −10°C and has a convection coefficient of 1200 W/m².K. The mass flow rate of the cold fluid and its specific heat are 1.2 kg/s and 1340 J/kg-K, respectively. (a) Assuming the flow is fully developed, find out the convection coefficient of the water flow. (b) What is the length of the heat exchanger? 1554 W/m²K 2 21.9m Water Cold Fluid