A flat plate solar collector, 6 ft by 12 ft, is mounted on the roof of a house. The outer surface of the collector is at 110oF and its emissivity is 0.9. The outside air is at 70oF and the sky has an effective temperature for radiation of 45oF. The collector transfers heat by natural convection to the air with a heat transfer coefficient of 3.2 Btu/h.ft2.oF and also transfers heat by radiation to the sky. Calculate the total heat loss from the solar collector.