I've done the question would like for clarification on my answersSolar heated hot air (Cp= 1010 J/kg.quot;C) is used to heat water (Cp= 4180 J/kg'quot;C) in a double pipe counter flow heat exchanger. Air enters the heat exchanger at 90quot;C at a rate of 0.3 kg/s, while water enters at 22quot;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.'C. The length of the tube is 12 m and the internal diameter of the tube is 1.2 cm. Determine a) the effectiveness of heat exchangerNTU = 0.11944Area = 0.45239 m^2c = 0.72488; where c,max = 418 W/'C c,min = 303 W/'Ceffectiveness = 0.1083 lt;------ final answerb) the outlet temperatures of the water and the airQ actual = 2231.4 WTc,out = 27.34 C and Th,out = 82.64 C lt;----- final answerare the answers correct?
I keep a programme developed by engineering students under my supervision, years ago. Feeding the information provided by you, I present the the whole result after running the programme. Your calculations are OK. Number of Transfer Unit (NTU) = 0.1194429 Heat Exchange Rate (Q) = 2230.982 W Hot Fluid Temperature At Inlet T(h,i) = 90 Centigrade Cold Fluid Temperature At Inlet T(c,i) = 22 Centigrade Hot Fluid Temperature At Outlet T(h,o) = 82.63702 Centigrade Cold Fluid Temperature At Outlet T(c,o) = 27.33728 Centigrade Cold Fluid Mass Flow Rate = 0.1 kg/s Hot Fluid Mass Flow Rate = 0.3 kg/s Overall Coefficient of Heat Transfer (U) = 80 W/Sq.m.K Area of Heat Transfer (A) = 0.45239 Sq.m.
