Whisk together the sugar, cream, milk, cocoa, cinnamon, salt, and orange zest in a medium size saucepan. Bring to a boil and then reduce to a simmer while stirring occasionally for 2 minutes. Add the chocolate chips and continue stirring while the chocolate melts. Remove from the heat and stir in the orange juice and vanilla extract. Let cool and then chill in the refrigerator for at least 4 hours. Pour the chilled mixture into your ice cream machine and process according to the manufacturer's directions. Enjoy!