In a dairy plant, milk at 4 degreesC is pasteurized continuously at 72 degreesC 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 18degreesC before it is finally refrigerated back to 4 degreesC. To save energy and money, the plant installs a re generator that has an effectiveness of 82 percent. If the cost of natural gas is $1.04/therm (1 therm = 105,500 kJ), determine how much more energy and money the re generator will save this company per year and the annual reduction in entropy generation. 

Solution