FE 356 PROBLEM SET NO 2
Macroscopic Energy Balances
An electrical coil is used to heat 80 L of oil in a closed vessel. The oil is initially at 25C. The coil delivers a power as a function of time; 0.0520tQe power in kW. At time zero, 2L/min of oil at 15c enters the vesselwhile the same amount discharges from it. At the same time 30 kj/min of heat is lost from the system. Given; 800 3 kg/m, Cp=2.5 kj/kgC. Determine;
a) the temperature of oil as a function of time,
b) the time required fort he temperature of oil t oto 80C
c) the maximum temperature.
Example: Air humidity 1H exit air leaves the drier with humidity 2H of time. enters into a drier containing a wet solid with a% moisture