In a large saucepan, heat sugar and water over medium heat until sugar is dissolved, stirring frequently. Stir in lemon zest strips. Bring to a boil. Reduce heat; simmer, uncovered, for 5 minutes. Remove from the heat; cool slightly.
Stir in lemon juice; cover and refrigerate until chilled. Discard lemon peel. Pour mixture into a large pitcher; gradually stir in club soda.