1. An oil heater heats 100 kg per minute of oil from 30°C to 100°C in a counter-flow heat exchanger. The average specific heat of the oil is 2.5 kJ/kg- C. Exhaust gases used for heating enter the heater with an average specific heat of 1 kJ/kg-°C, a mass flow rate of 200 kg/min and an initial temperature of 200°C. The overall heat transfer coefficient is 80 W/m² - C. Determine the heating surface area in m².

1. An oil heater heats 100 kg per minute of oil from 30°C to 100°C in a counter-flow heat exchanger. The average specific heat of the oil is 2.5 kJ/kg- C. Exhaust gases used for heating enter the heater with an average specific heat of 1 kJ/kg-°C, a mass flow rate of 200 kg/min and an initial temperature of 200°C. The overall heat transfer coefficient is 80 W/m² - C. Determine the heating surface area in m².

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

! Required information Consider a water-to-water counterflow heat exchanger with these specifications. Hot water enters at 70°C while cold water enters at 20°C. The exit temperature of the hot water is 15°C greater than that of the cold water, and the mass flow rate of the hot water is 50 percent greater than that of the cold water. The product of heat transfer surface area and the overall heat transfer coefficient is 2200 W/K. Take the specific heat of both cold and hot water to be cp= 4180 J/kg.°C. NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Cold water 20°C Hot water 40 °C Th, in Determine the effectiveness of the heat exchanger. The effectiveness of the heat exchanger is 0.72 *
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.
In a processing plant, waste heat is to be recovered from a hot oil stream into a cold water stream using a parallel-flow heat exchanger with 0.75 effectiveness. The hot oil enters the heat exchanger at 285 °C with a mass flow rate of 25.0 kg/min while the cold water flows into the heat exchanger at 35 °C with a mass flow rate of 48 kg/min. The specific heat capacities of the oil and the water are 2.2 kJ/kg.K and 4.2 kl/kg.K, respectively. The convective heat transfer coefficient on the oil side of the heat exchanger is 58 W/m?.K and that on the water side is 102 w/m².K. Neglect any thermal resistance at the heat transfer wall separating the oil and water streams in the heat exchanger. (a) Calculate the outlet temperatures of the oil and cold water streams in the heat exchanger. (b) Find the number of transfer units (N) of the heat exchanger. (c) Determine the heat transfer area required for the heat exchanger. It is given that for a parallel flow heat exchanger, the effectiveness (e)…
A well-insulated heat exchanger is to heat water (cp = 4.18 kJ/kg-°C) from 25°C to 60°C at a rate of 0.5kg/s. %3D The heating is to be accomplished by geothermal water (cp = 4.31 kJ/kg-°C) available at 140°C at a mass flow rate of %3D 0.5 kg/s. What is the temperature of exit Brine. Water 25°C Brine 140°C 60°C
A steam power plant is equipped with a condenser that removes 300 MW of heat from steam condensing at 30°C. The tubes of the heat exchanger have an internal diameter of 2 cm, and the overall heat transfer coefficient is 3500 W/m² °C. The cooling is provided by cooling water from a surrounding river, which enters the tubes at 18°C and leaves at 26°C. Determine the heat transfer surface area in m². (A) 19, 600 B 20, 600 11, 770 D) 18, 600
An economizer in a boiler has a flow of water inside the pipes and hot gases on the outside flowing across the pipes. The flow rate of gases is 2,000 tons/hr and the gases are cooled from 390°C to 200°C. The specific heat of the gas is 1005 J/kg K. Water is heated (under pressure) from 100°C to 220°C. Assuming an overall heat transfer coefficient of 35 W/m^2K, determine the area required. Assume that the airflow is mixed.
A fruit juice is being heated in an indirect heat exchanger using steam as a heating medium. The product fl ows through the heat exchanger at a rate of 1500 kg/h and the inlet temperature is 20C. Determine the quantity of steam required to heat the product to 100C when only latent heat of vaporization (2200 kJ/kg) is used for heating. The specifi c heat of the product is 4 kJ/(kg C).
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 heat exchanger is to heat water (cp = 4.18 kJ/kg·oC) from 25oC to 60oC at a rate of 0.2 kg/s. The heating is to be accomplished by geothermal water (cp = 4.31 kJ/kg·oC) available at 159oC at a mass flow rate of 0.3 kg/s. Find the exit temperature of geothermal water.
A single-pass, cross-flow heat exchanger uses hot exhaust gases (mixed) to heat water (unmixed) from 30°C to 80°C at a rate of 5.25 kg/s. The exhaust gases enter and exit the exchanger at 225°C and 100°C, respectively. What is the mass flow rate of the hot gases (kg/s) ? Water : c = 4184 J/kg K, Hot gases 1019 J/kg K :c = Select one: %3D
Q.2. Air enters a steady-flow heat exchanger with a mass flow rate of 2 kg/s as shown in Figure. Determine (a) the rate of heat transfer to the air in the heat exchanger, (b) the power output from the turbine assuming no heat loss, and (c) the velocity at exit from the nozzle. (Cp atr = 1.005 kJ/kg. K) T=600 C T- 12 C V=3 m/s Air Нeat v-3 m/s Exchanger Turbine T= 200 C V - 25 m/s T= 160 C Nozzle
Hot water (Cp= 4.188 kJ/kg.K) with mass flow rate of 2.5 kg/s at 100 C enters a thin-walled concentric tube counterflow heat exchanger with a surface area of 23 m, and an overall heat transfer coefficient of 1000 W/m^2K. Cold water (Cp= 4.178 kJ/kg.K) with mass flow rate of 5 kg/s enters the heat exchanger at 20 C. After a period of operation, the overall heat transfer coefficient is reduced to 500 W/m^2K determine the fouling factor that caused the reduction in the overall heat transfer coefficient.