The owners of two 1939 refrigerators have won a contest to identify the oldest refrigerators in Rhode Island. National Grid and Sears sponsored the contest to highlight energy efficiency and a program that rewards the utility’s customers for getting rid of old appliances. The contest ended in a tie after Robert Midwood of Cranston and Edward Miracle of Greenville each turned in 73-year-old General Electric units. They both won a $1,000 gift card good toward the purchase of a newer model. More than 3,400 appliances were picked up during the contest. National Grid offers customers a $50 incentive if they allow their old refrigerator or freezer to be picked up for recycling. The utility says older models consume as much as four times the energy of a newer unit.