For a production of 7000 liter of hot water at 75 °C per hour, a boiler fired with natural gas (Calorific value of 42 MJ/kg) and shell and tube heat exchanger is used. The cold water inters the heat exchanger at 8 °C and pressure of 300 kPa as shown in Figure Q4. Bolier 80°C 60°C 75°C 8°C Figure Q4 The circulation water inters the boiler at 60 °C and leaves at 80 °C and inters the shell side of the heat exchanger with a heat convection coefficient of 4000 W/m² °C. The hot water tubes is thin with internal diameters of 16 mm and there are 10 tubes. a) Calculate the transferred heat flow b) Calculate the amount of natural gas required in kg/hour assuming that the boiler ef- ficiency is 90% and all the heat transferred from the circulation water is gained by the tubes hot water. c) Calculate the internal heat convection coefficient, for the hot water tubes d) Calculate the overall heat transfer coefficient e) Calculate the tubes service area required for the heat exchanger

For a production of 7000 liter of hot water at 75 °C per hour, a boiler fired with natural gas (Calorific value of 42 MJ/kg) and shell and tube heat exchanger is used. The cold water inters the heat exchanger at 8 °C and pressure of 300 kPa as shown in Figure Q4. Bolier 80°C 60°C 75°C 8°C Figure Q4 The circulation water inters the boiler at 60 °C and leaves at 80 °C and inters the shell side of the heat exchanger with a heat convection coefficient of 4000 W/m² °C. The hot water tubes is thin with internal diameters of 16 mm and there are 10 tubes. a) Calculate the transferred heat flow b) Calculate the amount of natural gas required in kg/hour assuming that the boiler ef- ficiency is 90% and all the heat transferred from the circulation water is gained by the tubes hot water. c) Calculate the internal heat convection coefficient, for the hot water tubes d) Calculate the overall heat transfer coefficient e) Calculate the tubes service area required for the heat exchanger

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter10: Heat Exchangers

Section: Chapter Questions

Problem 10.17P

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