A 60 HP standard ac motor is operated for 85% time in a year at 75% load with efficiency and power factor as 82% and 0.8, respectively. Standard ac motor is replaced by an energy efficient motor of same capacity. At 75% load, the efficiency and power factor of energy efficient motor are 88% and 0.9, respectively. Costs of standard ac motor and energy efficient motor are Rs. 1,10,000/- and Rs. 1,50,000/-, respectively. Taking energy consumption charge as Rs. 4/- per unit and kVA demand charge as Rs. 300/- per kVA per month, calculate the following:
(i). Annual energy saving,
(ii). Annual saving,
(iii). Payback period.