In: Mechanical Engineering
Question-4 (40%)
A 75-hp (shaft output) motor that has an efficiency of 91.0 percent is worn out and is to be replaced by a high efficiency motor that has an efficiency of 95.4 percent. The motor operates 4368 hours a year at a load factor of 0.75. Taking the cost of electricity to be $0.12/kWh, determine:
a) the amount of energy (kWh/year) and money ($/year) saved as a result of installing the high-efficiency motor instead of the standard motor. (20 points)
b) the simple payback period (in months) if the purchase prices of the standard and high-efficiency motors are $5449 and $5520, respectively. (10 points)
c) If the life of the motor is 2 years, is it cost effective to buy 91.0% efficiency motor or 95.4% efficiency motor? Explain. (10 points)