A 12-ft^3 rigid tank contains refrigerant-134a at 40 psia and 55 percent quality. Heat is transferred now to the refrigerant from a source at 120 °F until the pressure rises to 60 psia. Assuming the surroundings to be at 75 °F, determine the a) amount of heat transfer between the source and the refrigerant and b) exergy destroyed during this process.