A residential district is to be heated by geothermal water in winter. On an average winter day, geothermal water enters the main heat exchanger network of the district at 90oC at arate of 70 kg/s and leaves the heat exchangers at 50oC. How much revenue will be generated if total winter period can be taken to be equivalent to 2500 hours of these average conditions and geothermal heat is sold at a price of $1.20/105 kJ.