Geothermal water (cp = 4250 J/kg·K) at 75°C is to be used to heat fresh water (cp = 4180 J/kg·K) at 17°C at a rate of 1.2 kg/s in a double-pipe counter-flow heat exchanger. The heat transfer surface area is 25 m2, the overall heat transfer coefficient is 480 W/m2·K, and the mass flow rate of geothermal water is larger than that of fresh water. If the effectiveness of the heat exchanger is desired to be 0.823, determine the mass flow rate of geothermal water and the outlet temperatures of both fluids.

Geothermal water (cp = 4250 J/kg·K) at 75°C is to be used to heat fresh water (cp = 4180 J/kg·K) at 17°C at a rate of 1.2 kg/s in a double-pipe counter-flow heat exchanger. The heat transfer surface area is 25 m2, the overall heat transfer coefficient is 480 W/m2·K, and the mass flow rate of geothermal water is larger than that of fresh water. If the effectiveness of the heat exchanger is desired to be 0.823, determine the mass flow rate of geothermal water and the outlet temperatures of both fluids.

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.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.54P

See similar textbooks

Similar questions

In a textile manufacturing plant, the waste dyeing water (cp = 4295 J/kg·K) at 75°C is to be used to preheat fresh water (cp = 4180 J/kg·K) at 15°C at the same flow rate in a double-pipe counter-flow heat exchanger. The heat transfer surface area of the heat exchanger is 1.65 m2 and the overall heat transfer coefficient is 625 W/m2·K. If the rate of heat transfer in the heat exchanger is 35 kW, determine the outlet temperature and the mass flow rate of each fluid stream.
Water (cp = 4180 J/kg·K) is to be heated by solarheated hot air (cp = 1010 J/kg·K) in a double-pipe counter- flow heat exchanger. Air enters the heat exchanger at 90°C at a rate of 0.3 kg/s, while water enters at 22°C at a rate of 0.1 kg/s. The overall heat transfer coefficient based on the inner side of the tube is given to be 80 W/m2·K. The length of the tube is 12 m and the internal diameter of the tube is 1.2 cm. Determine the outlet temperatures of the water and the air.
Hot exhaust gases of a stationary diesel engine are to be used to generate steam in an evaporator. Exhaust gases (cp = 1051 J/kg·K) enter the heat exchanger at 550°C at a rate of 0.25 kg/s while water enters as saturated liquid and evaporates at 200°C (hfg = 1941 kJ/kg). The heat transfer surface area of the heat exchanger based on water side is 0.5 m2 and overall heat transfer coefficient is 1780 W/m2·K. Determine the rate of heat transfer, the exit temperature of exhaust gases, and the rate of evaporation of water.
Ethanol is vaporized at 78°C (hfg = 846 kJ/kg) in a double-pipe parallel-flow heat exchanger at a rate of 0.03 kg/s by hot oil (cp = 2200 J/kg·K) that enters at 120°C. If the heat transfer surface area and the overall heat transfer coefficients are 6.2 m2 and 320 W/m2·K, respectively, determine the outlet temperature and the mass flow rate of oil using (a) the LMTD method and (b) the «-NTU method.
Water (cp = 4180 J/kg·K) is to be heated by solar-heated hot air (cp = 1010 J/kg·K) in a double-pipe counter-flow heat exchanger. Air enters the heat exchanger at 102°C at a rate of 0.3 kg/s, while water enters at 25°C at a rate of 0.1 kg/s. The overall heat transfer coefficient based on the inner side of the tube is given as 80 W/m2·K. The length of the tube is 12 m and the internal diameter of the tube is 1.2 cm. Determine the outlet temperature of water. (Round the answer to a single decimal place.) The outlet temperature of water is ______ °C.
Water (cp = 4180 J/kg·K) is to be heated by solar-heated hot air (cp = 1010 J/kg·K) in a double-pipe counter-flow heat exchanger. Air enters the heat exchanger at 102°C at a rate of 0.3 kg/s, while water enters at 25°C at a rate of 0.1 kg/s. The overall heat transfer coefficient based on the inner side of the tube is given as 80 W/m2·K. The length of the tube is 12 m and the internal diameter of the tube is 1.2 cm.determine the outlet temperature of water and air.The outlet temperature of water is ____ CThe outlet temperature of air is ____C
Glycerin (cp = 2400 J/kg⋅°C) at 20°C and 0.5 kg/s is to be heated by ethylene glycol (cp = 2500 J/kg⋅°C) at 100°C and the same mass flow rate in a thin-walled double-pipe parallel-flow heat exchanger. The overall heat transfer coefficient is 380 W/m2⋅°C and the heat transfer surface area is 6.5 m2. Determine the rate of heat transfer. The rate of heat transfer is _____ kW.
How does a heat exchanger work? Where and when will you use a heat exchanger?
What is application of parallel flow heat exchanger? and counter flow heat exchanger?
Consider a shell-and-tube water-to-water heat exchanger with identical mass flow rates for both the hot- and cold-water streams. Now the mass flow rate of the cold water is reduced by half. Will the effectiveness of this heat exchanger increase, decrease, or remain the same as a result of this modification? Explain. Assume the overall heat transfer coefficient and the inlet temperatures remain the same.
Water (Cp = 4180 J/kg · °C) enters the 2.5-cm internal-diameter tube of a double-pipe counter-flow heat exchanger at 17°C at a rate of 3 kg/s. Water is heated by steam condensing at 120°C (hfg = 2203 kJ/kg) in the shell. If the overall heat transfer coefficient of the heat exchanger is 900 W/m2 · °C, determine the length of the tube required in order to heat the water to 80°C using (a) the LMTD method and (b) the Effectiveness-NTU method
Air (Cp = 1005 J/kg °C) enters a cross-flow heat exchanger at 10 C at a rate of 3 kg/s, where it is heated by a hot water stream (Cp = 4190 J/kg °C) that enters the heat exchanger at 95 °C at a rate of 1 kg/s. Determine the maximum heat transfer rate and the outlet temperatures of the cold and the hot water streams for that case.