A solar collector provides the hot water needs of a family for a period of 8 months except for four months of winter season. The collector supplies hot water at an average temperature of 60oC and the average temperature of cold water is 20oC. An examination of water bills indicates that the family uses an average of 6 tons of hot water from the solar collector per month. A natural gas water heater supplies hot water in winter months. The cost of natural gas is $1.35/therm (1 therm = 100,000 Btu = 105,500 kJ) and the efficiency of the heater is 88 percent. Determine the annual natural gas and cost savings to this family due to solar collector.