Unformatted text preview: heat exchanger and (b) the rate of entropy generation in the heat exchanger.
7–118 Chickens with an average mass of 2.2 kg and average
specific heat of 3.54 kJ/kg · °C are to be cooled by chilled
water that enters a continuous-flow-type immersion chiller at
0.5°C and leaves at 2.5°C. Chickens are dropped into the
chiller at a uniform temperature of 15°C at a rate of 250 chickens per hour and are cooled to an average temperature of 3°C
before they are taken out. The chiller gains heat from the surroundings at 25°C at a rate of 150 kJ/h. Determine (a) the rate
of heat removal from the chickens, in kW, and (b) the rate of
entropy generation during this chilling process.
7–119 In a dairy plant, milk at 4°C is pasteurized continuously at 72°C at a rate of 12 L/s for 24 hours a day and
365 days a year. The milk is heated to the pasteurizing temperature by hot water heated in a natural-gas-fired boiler that has
an efficiency of 82 percent. The pasteurized milk is then cooled
by cold water at 18°C before it is finally refrigerated back to
4°C. To save energy and money, the...
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