Consider a shell in tube heat exchanger for cooling oil using cold water. Oil fl
ID: 1849601 • Letter: C
Question
Consider a shell in tube heat exchanger for cooling oil using cold water. Oil flows through the inner tube at the rate of 0.65 kg/s while water flows through the annulus at the rate of 0.55 kg/s. The oil is to be cooled from 75?C to 50?C. The temperature of the entering water is 28?C. Oil and later may be treated as pure substances with constant specific heat capacities of 1.65 kJ/kg-K and 4.2 kJ/kg-K, respectively. Calculate the water temperature (K) at the exit, (a) if there is no heat loss from the heat exchanger to the surroundings, and (b) if heat is lost to the surroundings at a rate of 6 kW.Explanation / Answer
oil flow =0.65 water flow =0.55 the oil to be cooled by 75 -50 = 25 degrees the temp of water entering =28 C Sw=4.2 So =1.65 hence lets assuming the steady state the heat lost by the oil = heat gained by the water 1.65*25=4.2*(T-28) hence T=37.82 C A> ans is 37.82 C if the heat is lost to surroundings at 6KW 1.65*25-6=4.2(T-28) here T=36.39 C B>ans is 36.39 C cheers :)