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^2 and an overall heat transfer coefficient of 1000 W/m^2.K. Cold water (Cp= 4.178 kJ/kg.K) with mass flow rate of 5 kg/s enters the heat exchanger at 20 C. (A) Use the Effectiveness-_NTU method, determine the heat transfer rate for the heat exchanger. (B) Determine the outlet temperatures of the cold and hot fluids. (C) After a period of operation, the overall heat transfer coefficient is reduced to 500 W/m^2.K. determine the fouling factor that caused the reduction in the overall heat transfer coefficient.

Hot oil, which enter a cross-flow heat exchanger at 200 C and leave at 100 C, are used to heat water at a flow rate of 1.5 kg/s from 30 to 120 C. The overall heat transfer coefficient based on the water-side surface area is U = 220 W/m2 . K. Determine : a) the required water surface area Ac using the NTU method(let effectiveness €=0.65). b) Ac when we change the water outlet temperature to 130Cc) discuss the effect of changing the water outlet temperature to Ac? d)draw the temperature profile along the heat exchanger

! 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 *

DU - Moodle English (en) A counter-flow double pipe heat exchanger shown in the figure below is to heat water from 20°C to 100°C at the rate of 1.2kg/s. The heating is to be accomplished by geothermal water available at 160°C at a mass flow rate of 2kg/s. the inner tube is thin-walled and has a diameter of 1.5 cm. If the overall heat transfer coefficient of the heat exchanger is 640W/m². °C. The specific heat capacities of the water and geothermal are 4.18 KJ/Kg. °C and 4.13 KU/Kg."C respectively. Determine heat transfer in the hot water. on Hot geothermal water 160°C 2 kg/s Cold water 20°C 100 °C 1.2 kg/s D = 1.5 cm Select one: О а. 40.128KW O b. 40128KW O c. 4.0128KW O d. 401.28KW