A district cooling facility has the following load profile. Load (Tons) 10000 7500 The utility company charges SR 0.50/kWh from 12:00 to 18:00, and SR 0.1/kWh for all other times. The facility uses air-cooled chillers whose consumption varies with weather conditions as follows: 5000 1.2 kW/ton from midnight unt before 8:00 1.4 kW/ton from 8:00 until before 12:00 1.6 kW/ton from 12:00 until before 18:00 1.2 kW/ton from 18:00 to midnight The operation and maintenance cost of the plant is SR 2,000,000 per year. The facility owner would like to reduce electricity consumption, so the following options are considered: Option A: Use a load shifting strategy between 12:00 and 18:00 to avoid paying the high tariff. The existing air-cooled chillers will continue to be used. 2500 0 AL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Time of Day Option B: Similar to Option A, but the air-cooled chillers are replaced with water-cooled chillers that consume 0.8 kW/ton (constant throughout the 24 hours). Option C: Continue operation without any changes Option A requires a capital cost of SR 15,000,000 for the thermal energy storage tank, and the operation and maintenance cost will become SR 2,500,000 per year Option B requires a capital cost of SR 45,000,000 for the water-cooled chillers and thermal energy storage tank, and the operation and maintenance cost will become SR 4,000,000 per year Assume that the planning period is 25 years and the discount rate is 8%. a. Calculate the annual cost, in Saudi Riyals, for the original case (Option C). Include both electricity and operation and maintenance cost. [4 points] b. At what capacity (in tons) will the chillers operate when the load shifting strategy is implemented? [3 points] c. Calculate the annual savings (in Saudi Riyals) after implementing Option A. [5 points] d. Calculate the annual savings (in Saudi Riyals) after implementing Option B. [5 points] e. Draw the cash flow diagrams for Option A and Option B. [4 points] f. Calculate the net present value for Option A and Option B. [4 points] g. Which of the three options would you recommend? Justify your answer. [3 points]