Answer:No, Lake source cooling is not economically advantageous.
Explanation:
The cost of the lake source cooling is S30 greater than the cost of the refrigerator.
Though the lakes source option will bring additional income of S2400 for ten years this will only reduce it's cost to S2900 and this is still higher than the total cost of the refrigerator option of S2,120.
The straight line depreciation option on both options will not change this decision since it will have the same effect on both options.